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Török E, Tuinte WE, Campiglio M. Identifying the STAC3/Ca V1.1 interactions responsible for Ca V1.1 expression in skeletal muscle. Biophys J 2023; 122:376a. [PMID: 36783909 DOI: 10.1016/j.bpj.2022.11.2067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023] Open
Affiliation(s)
- Eniko Török
- Institute of Physiology, Medical University Innsbruck, Innsbruck, Austria
| | - Wietske E Tuinte
- Institute of Physiology, Medical University Innsbruck, Innsbruck, Austria
| | - Marta Campiglio
- Institute of Physiology, Medical University Innsbruck, Innsbruck, Austria
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Tuinte WE, Tuluc P, Campiglio M. STAC proteins inhibit the voltage dependent inactivation of l-type calcium channels. Biophys J 2023; 122:104a. [PMID: 36782450 DOI: 10.1016/j.bpj.2022.11.750] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023] Open
Affiliation(s)
- Wietske E Tuinte
- Institute of Physiology, Medical University Innsbruck, Innsbruck, Austria
| | - Petronel Tuluc
- Department of Pharmacology and Toxicology, Innsbruck University, Innsbruck, Austria
| | - Marta Campiglio
- Institute of Physiology, Medical University Innsbruck, Innsbruck, Austria
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Heiss MC, Fernandez-Quintero ML, Pelizzari S, El Ghaleb Y, Campiglio M, Tuluc P, Liedl KR, Flucher BE. Ionic interactions between gating charges and countercharges in voltage-sensing domain I independently regulate kinetics and voltage-dependence of Ca v1.1 gating. Biophys J 2023; 122:106a-107a. [PMID: 36782457 DOI: 10.1016/j.bpj.2022.11.759] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023] Open
Affiliation(s)
- Martin C Heiss
- Institute of Physiology, Medical University of Innsbruck, Innsbruck, Austria
| | | | - Simone Pelizzari
- Institute of Physiology, Medical University of Innsbruck, Innsbruck, Austria
| | - Yousra El Ghaleb
- Institute of Physiology, Medical University of Innsbruck, Innsbruck, Austria
| | - Marta Campiglio
- Institute of Physiology, Medical University of Innsbruck, Innsbruck, Austria
| | - Petronel Tuluc
- Department of Pharmacology and Toxicology, University of Innsbruck, Innsbruck, Austria
| | - Klaus R Liedl
- Institute of General, Inorganic and Theoretical Chemistry, University of Innsbruck, Innsbruck, Austria
| | - Bernhard E Flucher
- Institute of Physiology, Medical University of Innsbruck, Innsbruck, Austria
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El Ghaleb Y, Fernandez-Quintero ML, Campiglio M, Liedl KR, Plomp AS, Bakker DP, Motazacker MM, Kortüm F, Höing AS, Kutsche K, Flucher BE. Two newly identified CACNA1I variants linked to neurodevelopmental disorder and epilepsy differentially affect Ca v3.3 gating properties. Biophys J 2023; 122:107a. [PMID: 36782461 DOI: 10.1016/j.bpj.2022.11.763] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023] Open
Affiliation(s)
- Yousra El Ghaleb
- Institute of Physiology, Medical University of Innsbruck, Innsbruck, Austria
| | | | - Marta Campiglio
- Institute of Physiology, Medical University of Innsbruck, Innsbruck, Austria
| | - Klaus R Liedl
- Department of General, Inorganic and Theoretical Chemistry, University of Innsbruck, Innsbruck, Austria
| | - Astrid S Plomp
- Department of Human Genetics, University of Amsterdam, Amsterdam, Netherlands
| | - Dewi P Bakker
- Department of Pediatric Neurology, University of Amsterdam, Amsterdam, Netherlands
| | - Mahdi M Motazacker
- Department of Human Genetics, University of Amsterdam, Amsterdam, Netherlands
| | - Fanny Kortüm
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Anne-Sophie Höing
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Kerstin Kutsche
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Bernhard E Flucher
- Institute of Physiology, Medical University of Innsbruck, Innsbruck, Austria
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Campiglio M, Dyrda A, Tuinte WE, Török E. Ca V1.1 Calcium Channel Signaling Complexes in Excitation-Contraction Coupling: Insights from Channelopathies. Handb Exp Pharmacol 2023; 279:3-39. [PMID: 36592225 DOI: 10.1007/164_2022_627] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
In skeletal muscle, excitation-contraction (EC) coupling relies on the mechanical coupling between two ion channels: the L-type voltage-gated calcium channel (CaV1.1), located in the sarcolemma and functioning as the voltage sensor of EC coupling, and the ryanodine receptor 1 (RyR1), located on the sarcoplasmic reticulum serving as the calcium release channel. To this day, the molecular mechanism by which these two ion channels are linked remains elusive. However, recently, skeletal muscle EC coupling could be reconstituted in heterologous cells, revealing that only four proteins are essential for this process: CaV1.1, RyR1, and the cytosolic proteins CaVβ1a and STAC3. Due to the crucial role of these proteins in skeletal muscle EC coupling, any mutation that affects any one of these proteins can have devastating consequences, resulting in congenital myopathies and other pathologies.Here, we summarize the current knowledge concerning these four essential proteins and discuss the pathophysiology of the CaV1.1, RyR1, and STAC3-related skeletal muscle diseases with an emphasis on the molecular mechanisms. Being part of the same signalosome, mutations in different proteins often result in congenital myopathies with similar symptoms or even in the same disease.
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Affiliation(s)
- Marta Campiglio
- Institute of Physiology, Medical University Innsbruck, Innsbruck, Austria.
| | - Agnieszka Dyrda
- Institute of Physiology, Medical University Innsbruck, Innsbruck, Austria
| | - Wietske E Tuinte
- Institute of Physiology, Medical University Innsbruck, Innsbruck, Austria
| | - Enikő Török
- Institute of Physiology, Medical University Innsbruck, Innsbruck, Austria
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Tuinte WE, Török E, Mahlknecht I, Tuluc P, Flucher BE, Campiglio M. STAC3 determines the slow activation kinetics of Ca V 1.1 currents and inhibits its voltage-dependent inactivation. J Cell Physiol 2022; 237:4197-4214. [PMID: 36161458 DOI: 10.1002/jcp.30870] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Accepted: 08/23/2022] [Indexed: 11/06/2022]
Abstract
The skeletal muscle CaV 1.1 channel functions as the voltage-sensor of excitation-contraction (EC) coupling. Recently, the adaptor protein STAC3 was found to be essential for both CaV 1.1 functional expression and EC coupling. Interestingly, STAC proteins were also reported to inhibit calcium-dependent inactivation (CDI) of L-type calcium channels (LTCC), an important negative feedback mechanism in calcium signaling. The same could not be demonstrated for CaV 1.1, as STAC3 is required for its functional expression. However, upon strong membrane depolarization, CaV 1.1 conducts calcium currents characterized by very slow kinetics of activation and inactivation. Therefore, we hypothesized that the negligible inactivation observed in CaV 1.1 currents reflects the inhibitory effect of STAC3. Here, we inserted a triple mutation in the linker region of STAC3 (ETLAAA), as the analogous mutation abolished the inhibitory effect of STAC2 on CDI of CaV 1.3 currents. When coexpressed in CaV 1.1/STAC3 double knockout myotubes, the mutant STAC3-ETLAAA failed to colocalize with CaV 1.1 in the sarcoplasmic reticulum/membrane junctions. However, combined patch-clamp and calcium recording experiments revealed that STAC3-ETLAAA supports CaV 1.1 functional expression and EC coupling, although at a reduced extent compared to wild-type STAC3. Importantly, STAC3-ETLAAA coexpression dramatically accelerated the kinetics of activation and inactivation of CaV 1.1 currents, suggesting that STAC3 determines the slow CaV 1.1 currents kinetics. To examine if STAC3 specifically inhibits the CDI of CaV 1.1 currents, we performed patch-clamp recordings using calcium and barium as charge carriers in HEK cells. While CaV 1.1 displayed negligible CDI with STAC3, this did not increase in the presence of STAC3-ETLAAA. On the contrary, our data demonstrate that STAC3 specifically inhibits the voltage-dependent inactivation (VDI) of CaV 1.1 currents. Altogether, these results designate STAC3 as a crucial determinant for the slow activation kinetics of CaV 1.1 currents and implicate STAC proteins as modulators of both components of inactivation of LTCC.
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Affiliation(s)
- Wietske E Tuinte
- Institute of Physiology, Medical University Innsbruck, Innsbruck, Austria
| | - Enikő Török
- Institute of Physiology, Medical University Innsbruck, Innsbruck, Austria
| | - Irene Mahlknecht
- Institute of Physiology, Medical University Innsbruck, Innsbruck, Austria
| | - Petronel Tuluc
- Department of Pharmacology and Toxicology, Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innsbruck, Austria
| | - Bernhard E Flucher
- Institute of Physiology, Medical University Innsbruck, Innsbruck, Austria
| | - Marta Campiglio
- Institute of Physiology, Medical University Innsbruck, Innsbruck, Austria
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El Ghaleb Y, Ortner NJ, Posch W, Fernández-Quintero ML, Tuinte WE, Monteleone S, Draheim HJ, Liedl KR, Wilflingseder D, Striessnig J, Tuluc P, Flucher BE, Campiglio M. Calcium current modulation by the γ1 subunit depends on alternative splicing of CaV1.1. J Gen Physiol 2022; 154:e202113028. [PMID: 35349630 PMCID: PMC9037348 DOI: 10.1085/jgp.202113028] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Accepted: 03/08/2022] [Indexed: 01/01/2023] Open
Abstract
The skeletal muscle voltage-gated calcium channel (CaV1.1) primarily functions as a voltage sensor for excitation-contraction coupling. Conversely, its ion-conducting function is modulated by multiple mechanisms within the pore-forming α1S subunit and the auxiliary α2δ-1 and γ1 subunits. In particular, developmentally regulated alternative splicing of exon 29, which inserts 19 amino acids in the extracellular IVS3-S4 loop of CaV1.1a, greatly reduces the current density and shifts the voltage dependence of activation to positive potentials outside the physiological range. We generated new HEK293 cell lines stably expressing α2δ-1, β3, and STAC3. When the adult (CaV1.1a) and embryonic (CaV1.1e) splice variants were expressed in these cells, the difference in the voltage dependence of activation observed in muscle cells was reproduced, but not the reduced current density of CaV1.1a. Only when we further coexpressed the γ1 subunit was the current density of CaV1.1a, but not that of CaV1.1e, reduced by >50%. In addition, γ1 caused a shift of the voltage dependence of inactivation to negative voltages in both variants. Thus, the current-reducing effect of γ1, unlike its effect on inactivation, is specifically dependent on the inclusion of exon 29 in CaV1.1a. Molecular structure modeling revealed several direct ionic interactions between residues in the IVS3-S4 loop and the γ1 subunit. However, substitution of these residues by alanine, individually or in combination, did not abolish the γ1-dependent reduction of current density, suggesting that structural rearrangements in CaV1.1a induced by inclusion of exon 29 may allosterically empower the γ1 subunit to exert its inhibitory action on CaV1.1 calcium currents.
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Affiliation(s)
- Yousra El Ghaleb
- Institute of Physiology, Department of Physiology and Medical Physics, Medical University Innsbruck, Innsbruck, Austria
| | - Nadine J. Ortner
- Department of Pharmacology and Toxicology, Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innsbruck, Austria
| | - Wilfried Posch
- Institute of Hygiene and Medical Microbiology, Medical University of Innsbruck, Innsbruck, Austria
| | | | - Wietske E. Tuinte
- Institute of Physiology, Department of Physiology and Medical Physics, Medical University Innsbruck, Innsbruck, Austria
| | - Stefania Monteleone
- Institute of General, Inorganic and Theoretical Chemistry, University of Innsbruck, Innsbruck, Austria
| | - Henning J. Draheim
- Boehringer Ingelheim Pharma GmbH & Co KG, CNS Research, Biberach an der Riss, Germany
| | - Klaus R. Liedl
- Institute of General, Inorganic and Theoretical Chemistry, University of Innsbruck, Innsbruck, Austria
| | - Doris Wilflingseder
- Institute of Hygiene and Medical Microbiology, Medical University of Innsbruck, Innsbruck, Austria
| | - Jörg Striessnig
- Department of Pharmacology and Toxicology, Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innsbruck, Austria
| | - Petronel Tuluc
- Department of Pharmacology and Toxicology, Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innsbruck, Austria
| | - Bernhard E. Flucher
- Institute of Physiology, Department of Physiology and Medical Physics, Medical University Innsbruck, Innsbruck, Austria
| | - Marta Campiglio
- Institute of Physiology, Department of Physiology and Medical Physics, Medical University Innsbruck, Innsbruck, Austria
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Ablinger C, Eibl C, Geisler SM, Campiglio M, Stephens GJ, Missler M, Obermair GJ. α 2δ-4 and Cachd1 Proteins Are Regulators of Presynaptic Functions. Int J Mol Sci 2022; 23:9885. [PMID: 36077281 PMCID: PMC9456004 DOI: 10.3390/ijms23179885] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 08/15/2022] [Accepted: 08/24/2022] [Indexed: 11/17/2022] Open
Abstract
The α2δ auxiliary subunits of voltage-gated calcium channels (VGCC) were traditionally regarded as modulators of biophysical channel properties. In recent years, channel-independent functions of these subunits, such as involvement in synapse formation, have been identified. In the central nervous system, α2δ isoforms 1, 2, and 3 are strongly expressed, regulating glutamatergic synapse formation by a presynaptic mechanism. Although the α2δ-4 isoform is predominantly found in the retina with very little expression in the brain, it was recently linked to brain functions. In contrast, Cachd1, a novel α2δ-like protein, shows strong expression in brain, but its function in neurons is not yet known. Therefore, we aimed to investigate the presynaptic functions of α2δ-4 and Cachd1 by expressing individual proteins in cultured hippocampal neurons. Both α2δ-4 and Cachd1 are expressed in the presynaptic membrane and could rescue a severe synaptic defect present in triple knockout/knockdown neurons that lacked the α2δ-1-3 isoforms (α2δ TKO/KD). This observation suggests that presynaptic localization and the regulation of synapse formation in glutamatergic neurons is a general feature of α2δ proteins. In contrast to this redundant presynaptic function, α2δ-4 and Cachd1 differentially regulate the abundance of presynaptic calcium channels and the amplitude of presynaptic calcium transients. These functional differences may be caused by subtle isoform-specific differences in α1-α2δ protein-protein interactions, as revealed by structural homology modelling. Taken together, our study identifies both α2δ-4 and Cachd1 as presynaptic regulators of synapse formation, differentiation, and calcium channel functions that can at least partially compensate for the loss of α2δ-1-3. Moreover, we show that regulating glutamatergic synapse formation and differentiation is a critical and surprisingly redundant function of α2δ and Cachd1.
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Affiliation(s)
- Cornelia Ablinger
- Institute of Physiology, Medical University Innsbruck, 6020 Innsbruck, Austria
| | - Clarissa Eibl
- Division Physiology, Department of Pharmacology, Physiology and Microbiology, Karl Landsteiner University of Health Sciences, 3500 Krems, Austria
| | - Stefanie M. Geisler
- Department Pharmacology and Toxicology, University of Innsbruck, 6020 Innsbruck, Austria
| | - Marta Campiglio
- Institute of Physiology, Medical University Innsbruck, 6020 Innsbruck, Austria
| | - Gary J. Stephens
- Reading School of Pharmacy, University of Reading, Reading RG6 6UB, UK
| | - Markus Missler
- Institute of Anatomy and Molecular Neurobiology, Westfälische Wilhelms-University, 48149 Münster, Germany
| | - Gerald J. Obermair
- Institute of Physiology, Medical University Innsbruck, 6020 Innsbruck, Austria
- Division Physiology, Department of Pharmacology, Physiology and Microbiology, Karl Landsteiner University of Health Sciences, 3500 Krems, Austria
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Yang ZF, Panwar P, McFarlane CR, Tuinte WE, Campiglio M, Van Petegem F. Structures of the junctophilin/voltage-gated calcium channel interface reveal hot spot for cardiomyopathy mutations. Proc Natl Acad Sci U S A 2022; 119:e2120416119. [PMID: 35238659 PMCID: PMC8916002 DOI: 10.1073/pnas.2120416119] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Accepted: 01/31/2022] [Indexed: 01/19/2023] Open
Abstract
SignificanceIon channels have evolved the ability to communicate with one another, either through protein-protein interactions, or indirectly via intermediate diffusible messenger molecules. In special cases, the channels are part of different membranes. In muscle tissue, the T-tubule membrane is in proximity to the sarcoplasmic reticulum, allowing communication between L-type calcium channels and ryanodine receptors. This process is critical for excitation-contraction coupling and requires auxiliary proteins like junctophilin (JPH). JPHs are targets for disease-associated mutations, most notably hypertrophic cardiomyopathy mutations in the JPH2 isoform. Here we provide high-resolution snapshots of JPH, both alone and in complex with a calcium channel peptide, and show how this interaction is targeted by cardiomyopathy mutations.
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Affiliation(s)
- Zheng Fang Yang
- Department of Biochemistry and Molecular Biology, The Life Sciences Institute, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Pankaj Panwar
- Department of Biochemistry and Molecular Biology, The Life Sciences Institute, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Ciaran R. McFarlane
- Department of Biochemistry and Molecular Biology, The Life Sciences Institute, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Wietske E. Tuinte
- Institute of Physiology, Medical University of Innsbruck, Innsbruck, 6020 Austria
| | - Marta Campiglio
- Institute of Physiology, Medical University of Innsbruck, Innsbruck, 6020 Austria
| | - Filip Van Petegem
- Department of Biochemistry and Molecular Biology, The Life Sciences Institute, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
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Tuinte WE, Tuluc P, Flucher BE, Campiglio M. STAC proteins inhibit calcium and voltage dependent inactivation of L-type calcium channels. Biophys J 2022. [DOI: 10.1016/j.bpj.2021.11.2220] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022] Open
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11
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El Ghaleb Y, Ortner NJ, Posch W, Fernandez-Quintero ML, Tuinte WE, Monteleone S, Draheim HJ, Liedl KR, Wilflingseder D, Striessnig J, Tuluc P, Flucher BE, Campiglio M. Calcium current modulation by the γ1 subunit depends on alternative splicing of Cav1.1. Biophys J 2022. [DOI: 10.1016/j.bpj.2021.11.2257] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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12
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Fang Yang Z, Panwar P, McFarlane C, Campiglio M, Tuinte WE, Van Petegem F. Crystallographic insights into cardiomyopathy mutations and voltage-gated calcium channel targeting by junctophilins. Biophys J 2022. [DOI: 10.1016/j.bpj.2021.11.2590] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
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El Ghaleb Y, Fernández-Quintero ML, Monteleone S, Tuluc P, Campiglio M, Liedl KR, Flucher BE. Ion-pair interactions between voltage-sensing domain IV and pore domain I regulate Ca V1.1 gating. Biophys J 2021; 120:4429-4441. [PMID: 34506774 PMCID: PMC8553663 DOI: 10.1016/j.bpj.2021.09.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Revised: 07/29/2021] [Accepted: 09/02/2021] [Indexed: 11/21/2022] Open
Abstract
The voltage-gated calcium channel CaV1.1 belongs to the family of pseudo-heterotetrameric cation channels, which are built of four structurally and functionally distinct voltage-sensing domains (VSDs) arranged around a common channel pore. Upon depolarization, positive gating charges in the S4 helices of each VSD are moved across the membrane electric field, thus generating the conformational change that prompts channel opening. This sliding helix mechanism is aided by the transient formation of ion-pair interactions with countercharges located in the S2 and S3 helices within the VSDs. Recently, we identified a domain-specific ion-pair partner of R1 and R2 in VSD IV of CaV1.1 that stabilizes the activated state of this VSD and regulates the voltage dependence of current activation in a splicing-dependent manner. Structure modeling of the entire CaV1.1 in a membrane environment now revealed the participation in this process of an additional putative ion-pair partner (E216) located outside VSD IV, in the pore domain of the first repeat (IS5). This interdomain interaction is specific for CaV1.1 and CaV1.2 L-type calcium channels. Moreover, in CaV1.1 it is sensitive to insertion of the 19 amino acid peptide encoded by exon 29. Whole-cell patch-clamp recordings in dysgenic myotubes reconstituted with wild-type or E216 mutants of GFP-CaV1.1e (lacking exon 29) showed that charge neutralization (E216Q) or removal of the side chain (E216A) significantly shifted the voltage dependence of activation (V1/2) to more positive potentials, suggesting that E216 stabilizes the activated state. Insertion of exon 29 in the GFP-CaV1.1a splice variant strongly reduced the ionic interactions with R1 and R2 and caused a substantial right shift of V1/2, whereas no further shift of V1/2 was observed on substitution of E216 with A or Q. Together with our previous findings, these results demonstrate that inter- and intradomain ion-pair interactions cooperate in the molecular mechanism regulating VSD function and channel gating in CaV1.1.
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Affiliation(s)
- Yousra El Ghaleb
- Department of Physiology and Medical Physics, Institute of Physiology, Medical University Innsbruck, Innsbruck, Austria
| | - Monica L Fernández-Quintero
- Department of Physiology and Medical Physics, Institute of Physiology, Medical University Innsbruck, Innsbruck, Austria; Department of General, Inorganic and Theoretical Chemistry, and Center for Molecular Biosciences Innsbruck
| | - Stefania Monteleone
- Department of General, Inorganic and Theoretical Chemistry, and Center for Molecular Biosciences Innsbruck; Evotec (UK) Ltd., Abingdon, Oxfordshire, United Kingdom
| | - Petronel Tuluc
- Department of Pharmacology and Toxicology, Institute of Pharmacy and Center for Molecular Biosciences, University of Innsbruck, Innsbruck, Austria
| | - Marta Campiglio
- Department of Physiology and Medical Physics, Institute of Physiology, Medical University Innsbruck, Innsbruck, Austria
| | - Klaus R Liedl
- Department of General, Inorganic and Theoretical Chemistry, and Center for Molecular Biosciences Innsbruck
| | - Bernhard E Flucher
- Department of Physiology and Medical Physics, Institute of Physiology, Medical University Innsbruck, Innsbruck, Austria.
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14
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El Ghaleb Y, Schneeberger PE, Fernández-Quintero ML, Geisler SM, Pelizzari S, Polstra AM, van Hagen JM, Denecke J, Campiglio M, Liedl KR, Stevens CA, Person RE, Rentas S, Marsh ED, Conlin LK, Tuluc P, Kutsche K, Flucher BE. CACNA1I gain-of-function mutations differentially affect channel gating and cause neurodevelopmental disorders. Brain 2021; 144:2092-2106. [PMID: 33704440 PMCID: PMC8422349 DOI: 10.1093/brain/awab101] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 01/05/2021] [Accepted: 01/06/2021] [Indexed: 12/11/2022] Open
Abstract
T-type calcium channels (Cav3.1 to Cav3.3) regulate low-threshold calcium spikes, burst firing and rhythmic oscillations of neurons and are involved in sensory processing, sleep, and hormone and neurotransmitter release. Here, we examined four heterozygous missense variants in CACNA1I, encoding the Cav3.3 channel, in patients with variable neurodevelopmental phenotypes. The p.(Ile860Met) variant, affecting a residue in the putative channel gate at the cytoplasmic end of the IIS6 segment, was identified in three family members with variable cognitive impairment. The de novo p.(Ile860Asn) variant, changing the same amino acid residue, was detected in a patient with severe developmental delay and seizures. In two additional individuals with global developmental delay, hypotonia, and epilepsy, the variants p.(Ile1306Thr) and p.(Met1425Ile), substituting residues at the cytoplasmic ends of IIIS5 and IIIS6, respectively, were found. Because structure modelling indicated that the amino acid substitutions differentially affect the mobility of the channel gate, we analysed possible effects on Cav3.3 channel function using patch-clamp analysis in HEK293T cells. The mutations resulted in slowed kinetics of current activation, inactivation, and deactivation, and in hyperpolarizing shifts of the voltage-dependence of activation and inactivation, with Cav3.3-I860N showing the strongest and Cav3.3-I860M the weakest effect. Structure modelling suggests that by introducing stabilizing hydrogen bonds the mutations slow the kinetics of the channel gate and cause the gain-of-function effect in Cav3.3 channels. The gating defects left-shifted and increased the window currents, resulting in increased calcium influx during repetitive action potentials and even at resting membrane potentials. Thus, calcium toxicity in neurons expressing the Cav3.3 variants is one likely cause of the neurodevelopmental phenotype. Computer modelling of thalamic reticular nuclei neurons indicated that the altered gating properties of the Cav3.3 disease variants lower the threshold and increase the duration and frequency of action potential firing. Expressing the Cav3.3-I860N/M mutants in mouse chromaffin cells shifted the mode of firing from low-threshold spikes and rebound burst firing with wild-type Cav3.3 to slow oscillations with Cav3.3-I860N and an intermediate firing mode with Cav3.3-I860M, respectively. Such neuronal hyper-excitability could explain seizures in the patient with the p.(Ile860Asn) mutation. Thus, our study implicates CACNA1I gain-of-function mutations in neurodevelopmental disorders, with a phenotypic spectrum ranging from borderline intellectual functioning to a severe neurodevelopmental disorder with epilepsy.
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Affiliation(s)
- Yousra El Ghaleb
- Institute of Physiology, Medical University Innsbruck, Innsbruck 6020, Austria
| | - Pauline E Schneeberger
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Hamburg 20251, Germany
| | - Monica L Fernández-Quintero
- Institute of Physiology, Medical University Innsbruck, Innsbruck 6020, Austria
- Institute of Theoretical Chemistry, University of Innsbruck, Innsbruck 6020, Austria
| | - Stefanie M Geisler
- Department of Pharmacology, University of Innsbruck, Innsbruck 6020, Austria
| | - Simone Pelizzari
- Institute of Physiology, Medical University Innsbruck, Innsbruck 6020, Austria
| | - Abeltje M Polstra
- Department of Clinical Genetics, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam, 1012 WX, The Netherlands
| | - Johanna M van Hagen
- Department of Clinical Genetics, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam, 1012 WX, The Netherlands
| | - Jonas Denecke
- Department of Pediatrics, University Medical Center Hamburg-Eppendorf, Hamburg 20251, Germany
| | - Marta Campiglio
- Institute of Physiology, Medical University Innsbruck, Innsbruck 6020, Austria
| | - Klaus R Liedl
- Institute of Theoretical Chemistry, University of Innsbruck, Innsbruck 6020, Austria
| | - Cathy A Stevens
- Department of Pediatrics, University of Tennessee College of Medicine, Chattanooga, TN 37403, USA
| | | | - Stefan Rentas
- Division of Genomic Diagnostics, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Eric D Marsh
- Division of Neurology, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Laura K Conlin
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Petronel Tuluc
- Department of Pharmacology, University of Innsbruck, Innsbruck 6020, Austria
| | - Kerstin Kutsche
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Hamburg 20251, Germany
| | - Bernhard E Flucher
- Institute of Physiology, Medical University Innsbruck, Innsbruck 6020, Austria
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15
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Schöpf CL, Ablinger C, Geisler SM, Stanika RI, Campiglio M, Kaufmann WA, Nimmervoll B, Schlick B, Brockhaus J, Missler M, Shigemoto R, Obermair GJ. Presynaptic α 2δ subunits are key organizers of glutamatergic synapses. Proc Natl Acad Sci U S A 2021; 118:e1920827118. [PMID: 33782113 PMCID: PMC8040823 DOI: 10.1073/pnas.1920827118] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
In nerve cells the genes encoding for α2δ subunits of voltage-gated calcium channels have been linked to synaptic functions and neurological disease. Here we show that α2δ subunits are essential for the formation and organization of glutamatergic synapses. Using a cellular α2δ subunit triple-knockout/knockdown model, we demonstrate a failure in presynaptic differentiation evidenced by defective presynaptic calcium channel clustering and calcium influx, smaller presynaptic active zones, and a strongly reduced accumulation of presynaptic vesicle-associated proteins (synapsin and vGLUT). The presynaptic defect is associated with the downscaling of postsynaptic AMPA receptors and the postsynaptic density. The role of α2δ isoforms as synaptic organizers is highly redundant, as each individual α2δ isoform can rescue presynaptic calcium channel trafficking and expression of synaptic proteins. Moreover, α2δ-2 and α2δ-3 with mutated metal ion-dependent adhesion sites can fully rescue presynaptic synapsin expression but only partially calcium channel trafficking, suggesting that the regulatory role of α2δ subunits is independent from its role as a calcium channel subunit. Our findings influence the current view on excitatory synapse formation. First, our study suggests that postsynaptic differentiation is secondary to presynaptic differentiation. Second, the dependence of presynaptic differentiation on α2δ implicates α2δ subunits as potential nucleation points for the organization of synapses. Finally, our results suggest that α2δ subunits act as transsynaptic organizers of glutamatergic synapses, thereby aligning the synaptic active zone with the postsynaptic density.
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Affiliation(s)
- Clemens L Schöpf
- Institute of Physiology, Medical University of Innsbruck, A-6020 Innsbruck, Austria
| | - Cornelia Ablinger
- Institute of Physiology, Medical University of Innsbruck, A-6020 Innsbruck, Austria
| | - Stefanie M Geisler
- Institute of Physiology, Medical University of Innsbruck, A-6020 Innsbruck, Austria
- Department of Pharmacology and Toxicology, University of Innsbruck, A-6020 Innsbruck, Austria
| | - Ruslan I Stanika
- Division of Physiology, Karl Landsteiner University of Health Sciences, A-3500 Krems, Austria
| | - Marta Campiglio
- Institute of Physiology, Medical University of Innsbruck, A-6020 Innsbruck, Austria
| | - Walter A Kaufmann
- Institute of Science and Technology Austria, A-3400 Klosterneuburg, Austria
| | - Benedikt Nimmervoll
- Institute of Physiology, Medical University of Innsbruck, A-6020 Innsbruck, Austria
| | - Bettina Schlick
- Institute of Physiology, Medical University of Innsbruck, A-6020 Innsbruck, Austria
| | - Johannes Brockhaus
- Institute of Anatomy and Molecular Neurobiology, Westfälische Wilhelms University, 48149 Münster, Germany
| | - Markus Missler
- Institute of Anatomy and Molecular Neurobiology, Westfälische Wilhelms University, 48149 Münster, Germany
| | - Ryuichi Shigemoto
- Institute of Science and Technology Austria, A-3400 Klosterneuburg, Austria
| | - Gerald J Obermair
- Institute of Physiology, Medical University of Innsbruck, A-6020 Innsbruck, Austria;
- Division of Physiology, Karl Landsteiner University of Health Sciences, A-3500 Krems, Austria
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16
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Fernández-Quintero ML, El Ghaleb Y, Tuluc P, Campiglio M, Liedl KR, Flucher BE. Structural determinants of voltage-gating properties in calcium channels. eLife 2021; 10:e64087. [PMID: 33783354 PMCID: PMC8099428 DOI: 10.7554/elife.64087] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Accepted: 03/29/2021] [Indexed: 12/20/2022] Open
Abstract
Voltage-gated calcium channels control key functions of excitable cells, like synaptic transmission in neurons and the contraction of heart and skeletal muscles. To accomplish such diverse functions, different calcium channels activate at different voltages and with distinct kinetics. To identify the molecular mechanisms governing specific voltage sensing properties, we combined structure modeling, mutagenesis, and electrophysiology to analyze the structures, free energy, and transition kinetics of the activated and resting states of two functionally distinct voltage sensing domains (VSDs) of the eukaryotic calcium channel CaV1.1. Both VSDs displayed the typical features of the sliding helix model; however, they greatly differed in ion-pair formation of the outer gating charges. Specifically, stabilization of the activated state enhanced the voltage dependence of activation, while stabilization of resting states slowed the kinetics. This mechanism provides a mechanistic model explaining how specific ion-pair formation in separate VSDs can realize the characteristic gating properties of voltage-gated cation channels.
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Affiliation(s)
- Monica L Fernández-Quintero
- Department of Physiology and Medical Physics, Medical University InnsbruckInnsbruckAustria
- Department of General, Inorganic and Theoretical Chemistry, University of InnsbruckInnsbruckAustria
| | - Yousra El Ghaleb
- Department of Physiology and Medical Physics, Medical University InnsbruckInnsbruckAustria
| | - Petronel Tuluc
- Department of Pharmacology and Toxicology, Institute of Pharmacy and Center for Molecular Biosciences, University of InnsbruckInnsbruckAustria
| | - Marta Campiglio
- Department of Physiology and Medical Physics, Medical University InnsbruckInnsbruckAustria
| | - Klaus R Liedl
- Department of General, Inorganic and Theoretical Chemistry, University of InnsbruckInnsbruckAustria
| | - Bernhard E Flucher
- Department of Physiology and Medical Physics, Medical University InnsbruckInnsbruckAustria
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17
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Rufenach B, Christy D, Flucher BE, Bui JM, Gsponer J, Campiglio M, Van Petegem F. Multiple Sequence Variants in STAC3 Affect Interactions with CaV1.1 and Excitation-Contraction Coupling. Structure 2020; 28:922-932.e5. [DOI: 10.1016/j.str.2020.05.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Revised: 04/03/2020] [Accepted: 05/11/2020] [Indexed: 10/24/2022]
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18
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Coste de Bagneaux P, von Elsner L, Bierhals T, Campiglio M, Johannsen J, Obermair GJ, Hempel M, Flucher BE, Kutsche K. A homozygous missense variant in CACNB4 encoding the auxiliary calcium channel beta4 subunit causes a severe neurodevelopmental disorder and impairs channel and non-channel functions. PLoS Genet 2020; 16:e1008625. [PMID: 32176688 PMCID: PMC7176149 DOI: 10.1371/journal.pgen.1008625] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Revised: 04/22/2020] [Accepted: 01/23/2020] [Indexed: 12/27/2022] Open
Abstract
P/Q-type channels are the principal presynaptic calcium channels in brain functioning in neurotransmitter release. They are composed of the pore-forming CaV2.1 α1 subunit and the auxiliary α2δ-2 and β4 subunits. β4 is encoded by CACNB4, and its multiple splice variants serve isoform-specific functions as channel subunits and transcriptional regulators in the nucleus. In two siblings with intellectual disability, psychomotor retardation, blindness, epilepsy, movement disorder and cerebellar atrophy we identified rare homozygous variants in the genes LTBP1, EMILIN1, CACNB4, MINAR1, DHX38 and MYO15 by whole-exome sequencing. In silico tools, animal model, clinical, and genetic data suggest the p.(Leu126Pro) CACNB4 variant to be likely pathogenic. To investigate the functional consequences of the CACNB4 variant, we introduced the corresponding mutation L125P into rat β4b cDNA. Heterologously expressed wild-type β4b associated with GFP-CaV1.2 and accumulated in presynaptic boutons of cultured hippocampal neurons. In contrast, the β4b-L125P mutant failed to incorporate into calcium channel complexes and to cluster presynaptically. When co-expressed with CaV2.1 in tsA201 cells, β4b and β4b-L125P augmented the calcium current amplitudes, however, β4b-L125P failed to stably complex with α1 subunits. These results indicate that p.Leu125Pro disrupts the stable association of β4b with native calcium channel complexes, whereas membrane incorporation, modulation of current density and activation properties of heterologously expressed channels remained intact. Wildtype β4b was specifically targeted to the nuclei of quiescent excitatory cells. Importantly, the p.Leu125Pro mutation abolished nuclear targeting of β4b in cultured myotubes and hippocampal neurons. While binding of β4b to the known interaction partner PPP2R5D (B56δ) was not affected by the mutation, complex formation between β4b-L125P and the neuronal TRAF2 and NCK interacting kinase (TNIK) seemed to be disturbed. In summary, our data suggest that the homozygous CACNB4 p.(Leu126Pro) variant underlies the severe neurological phenotype in the two siblings, most likely by impairing both channel and non-channel functions of β4b.
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Affiliation(s)
| | - Leonie von Elsner
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Tatjana Bierhals
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Marta Campiglio
- Department of Physiology and Medical Physics, Medical University Innsbruck, Innsbruck, Austria
| | - Jessika Johannsen
- Childrens Hospital, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Gerald J. Obermair
- Department of Physiology and Medical Physics, Medical University Innsbruck, Innsbruck, Austria
- Division Physiology, Karl Landsteiner University of Health Sciences, Krems, Austria
| | - Maja Hempel
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Bernhard E. Flucher
- Department of Physiology and Medical Physics, Medical University Innsbruck, Innsbruck, Austria
| | - Kerstin Kutsche
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
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19
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El Ghaleb Y, Campiglio M, Flucher BE. Correcting the R165K substitution in the first voltage-sensor of Ca V1.1 right-shifts the voltage-dependence of skeletal muscle calcium channel activation. Channels (Austin) 2019; 13:62-71. [PMID: 30638110 PMCID: PMC6380215 DOI: 10.1080/19336950.2019.1568825] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Revised: 01/08/2019] [Accepted: 01/08/2019] [Indexed: 11/18/2022] Open
Abstract
The voltage-gated calcium channel CaV1.1a primarily functions as voltage-sensor in skeletal muscle excitation-contraction (EC) coupling. In embryonic muscle the splice variant CaV1.1e, which lacks exon 29, additionally function as a genuine L-type calcium channel. Because previous work in most laboratories used a CaV1.1 expression plasmid containing a single amino acid substitution (R165K) of a critical gating charge in the first voltage-sensing domain (VSD), we corrected this substitution and analyzed its effects on the gating properties of the L-type calcium currents in dysgenic myotubes. Reverting K165 to R right-shifted the voltage-dependence of activation by ~12 mV in both CaV1.1 splice variants without changing their current amplitudes or kinetics. This demonstrates the exquisite sensitivity of the voltage-sensor function to changes in the specific amino acid side chains independent of their charge. Our results further indicate the cooperativity of VSDs I and IV in determining the voltage-sensitivity of CaV1.1 channel gating.
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Affiliation(s)
- Yousra El Ghaleb
- Department of Physiology and Medical Physics, Medical University Innsbruck, Innsbruck, Austria
| | - Marta Campiglio
- Department of Physiology and Medical Physics, Medical University Innsbruck, Innsbruck, Austria
| | - Bernhard E. Flucher
- Department of Physiology and Medical Physics, Medical University Innsbruck, Innsbruck, Austria
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20
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Costé de Bagneaux P, Campiglio M, Benedetti B, Tuluc P, Flucher BE. Role of putative voltage-sensor countercharge D4 in regulating gating properties of Ca V1.2 and Ca V1.3 calcium channels. Channels (Austin) 2019; 12:249-261. [PMID: 30001160 PMCID: PMC6161609 DOI: 10.1080/19336950.2018.1482183] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Voltage-dependent calcium channels (CaV) activate over a wide range of membrane potentials, and the voltage-dependence of activation of specific channel isoforms is exquisitely tuned to their diverse functions in excitable cells. Alternative splicing further adds to the stunning diversity of gating properties. For example, developmentally regulated insertion of an alternatively spliced exon 29 in the fourth voltage-sensing domain (VSD IV) of CaV1.1 right-shifts voltage-dependence of activation by 30 mV and decreases the current amplitude several-fold. Previously we demonstrated that this regulation of gating properties depends on interactions between positive gating charges (R1, R2) and a negative countercharge (D4) in VSD IV of CaV1.1. Here we investigated whether this molecular mechanism plays a similar role in the VSD IV of CaV1.3 and in VSDs II and IV of CaV1.2 by introducing charge-neutralizing mutations (D4N or E4Q) in the corresponding positions of CaV1.3 and in two splice variants of CaV1.2. In both channels the D4N (VSD IV) mutation resulted in a ̴5 mV right-shift of the voltage-dependence of activation and in a reduction of current density to about half of that in controls. However in CaV1.2 the effects were independent of alternative splicing, indicating that the two modulatory processes operate by distinct mechanisms. Together with our previous findings these results suggest that molecular interactions engaging D4 in VSD IV contribute to voltage-sensing in all examined CaV1 channels, however its striking role in regulating the gating properties by alternative splicing appears to be a unique property of the skeletal muscle CaV1.1 channel.
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Affiliation(s)
- Pierre Costé de Bagneaux
- a Department of Physiology and Medical Physics , Medical University of Innsbruck , Innsbruck , Austria
| | - Marta Campiglio
- a Department of Physiology and Medical Physics , Medical University of Innsbruck , Innsbruck , Austria
| | - Bruno Benedetti
- b Institute of Experimental Neuroregeneration Spinal Cord Injury and Tissue Regeneration Center Salzburg (SCI-TReCS) , Paracelsus Medical University , Salzburg , Austria
| | - Petronel Tuluc
- c Department of Pharmacology and Toxicology , University of Innsbruck , Innsbruck , Austria
| | - Bernhard E Flucher
- a Department of Physiology and Medical Physics , Medical University of Innsbruck , Innsbruck , Austria
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21
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Flucher BE, Campiglio M. STAC proteins: The missing link in skeletal muscle EC coupling and new regulators of calcium channel function. Biochim Biophys Acta Mol Cell Res 2019; 1866:1101-1110. [PMID: 30543836 DOI: 10.1016/j.bbamcr.2018.12.004] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Revised: 12/04/2018] [Accepted: 12/05/2018] [Indexed: 01/19/2023]
Abstract
Excitation-contraction coupling is the signaling process by which action potentials control calcium release and consequently the force of muscle contraction. Until recently, three triad proteins were known to be essential for skeletal muscle EC coupling: the voltage-gated calcium channel CaV1.1 acting as voltage sensor, the SR calcium release channel RyR1 representing the only relevant calcium source, and the auxiliary CaV β1a subunit. Whether CaV1.1 and RyR1 are directly coupled or whether their interaction is mediated by another triad protein is still unknown. The recent identification of the adaptor protein STAC3 as fourth essential component of skeletal muscle EC coupling prompted vigorous research to reveal its role in this signaling process. Accumulating evidence supports its possible involvement in linking CaV1.1 and RyR1 in skeletal muscle EC coupling, but also indicates a second, much broader role of STAC proteins in the regulation of calcium/calmodulin-dependent feedback regulation of L-type calcium channels.
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Affiliation(s)
- Bernhard E Flucher
- Department of Physiology and Medical Physics, Medical University Innsbruck, Schöpfstraße 41, A6020 Innsbruck, Austria.
| | - Marta Campiglio
- Department of Physiology and Medical Physics, Medical University Innsbruck, Schöpfstraße 41, A6020 Innsbruck, Austria
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22
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Geisler S, Schöpf CL, Stanika R, Kalb M, Campiglio M, Repetto D, Traxler L, Missler M, Obermair GJ. Presynaptic α 2δ-2 Calcium Channel Subunits Regulate Postsynaptic GABA A Receptor Abundance and Axonal Wiring. J Neurosci 2019; 39:2581-2605. [PMID: 30683685 PMCID: PMC6445987 DOI: 10.1523/jneurosci.2234-18.2019] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Revised: 01/03/2019] [Accepted: 01/08/2019] [Indexed: 01/26/2023] Open
Abstract
Presynaptic α2δ subunits of voltage-gated calcium channels regulate channel abundance and are involved in glutamatergic synapse formation. However, little is known about the specific functions of the individual α2δ isoforms and their role in GABAergic synapses. Using primary neuronal cultures of embryonic mice of both sexes, we here report that presynaptic overexpression of α2δ-2 in GABAergic synapses strongly increases clustering of postsynaptic GABAARs. Strikingly, presynaptic α2δ-2 exerts the same effect in glutamatergic synapses, leading to a mismatched localization of GABAARs. This mismatching is caused by an aberrant wiring of glutamatergic presynaptic boutons with GABAergic postsynaptic positions. The trans-synaptic effect of α2δ-2 is independent of the prototypical cell-adhesion molecules α-neurexins (α-Nrxns); however, α-Nrxns together with α2δ-2 can modulate postsynaptic GABAAR abundance. Finally, exclusion of the alternatively spliced exon 23 of α2δ-2 is essential for the trans-synaptic mechanism. The novel function of α2δ-2 identified here may explain how abnormal α2δ subunit expression can cause excitatory-inhibitory imbalance often associated with neuropsychiatric disorders.SIGNIFICANCE STATEMENT Voltage-gated calcium channels regulate important neuronal functions such as synaptic transmission. α2δ subunits modulate calcium channels and are emerging as regulators of brain connectivity. However, little is known about how individual α2δ subunits contribute to synapse specificity. Here, we show that presynaptic expression of a single α2δ variant can modulate synaptic connectivity and the localization of inhibitory postsynaptic receptors. Our findings provide basic insights into the development of specific synaptic connections between nerve cells and contribute to our understanding of normal nerve cell functions. Furthermore, the identified mechanism may explain how an altered expression of calcium channel subunits can result in aberrant neuronal wiring often associated with neuropsychiatric disorders such as autism or schizophrenia.
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Affiliation(s)
- Stefanie Geisler
- Division of Physiology, Medical University Innsbruck, 6020 Innsbruck, Austria, and
| | - Clemens L Schöpf
- Division of Physiology, Medical University Innsbruck, 6020 Innsbruck, Austria, and
| | - Ruslan Stanika
- Division of Physiology, Medical University Innsbruck, 6020 Innsbruck, Austria, and
| | - Marcus Kalb
- Division of Physiology, Medical University Innsbruck, 6020 Innsbruck, Austria, and
| | - Marta Campiglio
- Division of Physiology, Medical University Innsbruck, 6020 Innsbruck, Austria, and
| | - Daniele Repetto
- Institute of Anatomy and Molecular Neurobiology, Westfälische Wilhelms-University, 48149 Münster, Germany
| | - Larissa Traxler
- Division of Physiology, Medical University Innsbruck, 6020 Innsbruck, Austria, and
| | - Markus Missler
- Institute of Anatomy and Molecular Neurobiology, Westfälische Wilhelms-University, 48149 Münster, Germany
| | - Gerald J Obermair
- Division of Physiology, Medical University Innsbruck, 6020 Innsbruck, Austria, and
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23
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Campiglio M, Kaplan MM, Flucher BE. STAC3 incorporation into skeletal muscle triads occurs independent of the dihydropyridine receptor. J Cell Physiol 2018; 233:9045-9051. [PMID: 30071129 PMCID: PMC6334165 DOI: 10.1002/jcp.26767] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Accepted: 04/27/2018] [Indexed: 01/02/2023]
Abstract
Excitation‐contraction (EC) coupling in skeletal muscles operates through a physical interaction between the dihydropyridine receptor (DHPR), acting as a voltage sensor, and the ryanodine receptor (RyR1), acting as a calcium release channel. Recently, the adaptor protein SH3 and cysteine‐rich containing protein 3 (STAC3) has been identified as a myopathy disease gene and as an additional essential EC coupling component. STAC3 interacts with DHPR sequences including the critical EC coupling domain and has been proposed to function in linking the DHPR and RyR1. However, we and others demonstrated that incorporation of recombinant STAC3 into skeletal muscle triads critically depends only on the DHPR but not the RyR1. On the contrary, here, we provide evidence that endogenous STAC3 incorporates into triads in the absence of the DHPR in myotubes and muscle fibers of dysgenic mice. This finding demonstrates that STAC3 interacts with additional triad proteins and is consistent with its proposed role in directly or indirectly linking the DHPR with the RyR1.
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Affiliation(s)
- Marta Campiglio
- Department of Physiology, Medical University, Innsbruck, Innsbruck, Austria
| | - Mehmet M Kaplan
- Department of Physiology, Medical University, Innsbruck, Innsbruck, Austria
| | - Bernhard E Flucher
- Department of Physiology, Medical University, Innsbruck, Innsbruck, Austria
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24
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Botti C, Seregni E, Ménard S, Collini P, Tagliabue E, Campiglio M, Vergani B, Ghirelli C, Aiello P, Pilotti S, Bombardieri E. Two Novel Monoclonal Antibodies against the MUC4 Tandem Repeat Reacting with an Antigen Overexpressed by Lung Cancer. Int J Biol Markers 2018; 15:312-20. [PMID: 11192827 DOI: 10.1177/172460080001500406] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
In this study we investigated the immunochemical and cytochemical reactivity of two monoclonal antibodies against the 16-amino acid tandem repeat of MUC4 to demonstrate a possible variation of the mucin core peptide expression related to lung cancer. The immunocytochemical anti-MUC4 reactivity was analyzed in four lung cancer cell lines (Calu-1, Calu-3, H460, SKMES) and in other tumor cell lines, as well as in frozen materials from 21 lung adenocarcinomas (ACs), including five bronchioloalveolar carcinomas (BACs), and 11 squamous cell lung carcinomas (SqCCs). A weak fluorescence anti-MUC4 positivity (range: 10.3–16.2) was observed only in acetone-fixed lung cancer cell lines Calu-1, Calu-3 and H460. These three lung cancer cell lines also showed a cytoplasmic immunoperoxidase reactivity. The immunostaining in lung cancer tissues showed a granular cytoplasmic reactivity: 15/21 (71%) and 17/21 (80%) ACs were positive with BC-LuC18.2 and BC-LuCF12, respectively. All BACs were positive. Moderate to strong reactivity was present in well-differentiated ACs. In the normal lung parenchyma counterparts weak reactivity was found only in bronchiolar cells. All SqCCs were negative. Anti-MUC4 reactivity was also observed in the alveolar mucus. In conclusion, our anti-MUC4 MAbs detect a secretion product present in mucus and this product is elaborated by lung cancer cells and overexpressed in well-differentiated lung ACs.
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Affiliation(s)
- C Botti
- Division of Nuclear Medicine, Istituto Nazionale per lo Studio e la Cura dei Tumori, Milan, Italy
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25
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Campiglio M, de Bagneaux PC, Ortner NJ, Tuluc P, Flucher BE. STAC Proteins Associate to the IQ Domain of CaV1.2 and Inhibit Calcium-Dependent Inactivation. Biophys J 2018. [DOI: 10.1016/j.bpj.2017.11.3446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
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26
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Costé de Bagneaux P, Benedetti B, Tuluc P, Campiglio M, Flucher B. Probing the Voltage-Sensing Mechanism of CaV1.1 Calcium Channels at Single Channel Resolution. Biophys J 2018. [DOI: 10.1016/j.bpj.2017.11.3441] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
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27
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Wong King Yuen S, Campiglio M, Tung CC, Flucher B, Van Petegem F. Structural Insights into the STAC Adaptor Protein and Voltage-Gated Calcium Channel Interaction. Biophys J 2018. [DOI: 10.1016/j.bpj.2017.11.270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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Orlandi R, Cattaneo M, Troglio F, Campiglio M, Biunno I, Ménard S. Production of a Monoclonal Antibody Directed against the Recombinant SEL1L Protein. Int J Biol Markers 2018; 17:104-11. [PMID: 12113576 DOI: 10.1177/172460080201700205] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
SEL1L, highly similar to the C. elegans sel-1 gene, is a recently cloned human gene whose function is under investigation. SEL1L is differentially expressed in tumors and normal tissues and seems to play a role in tumor growth and aggressiveness. We used the recombinant N-terminus of the SEL1L protein to immunize a Balb/c mouse and produce a monoclonal antibody. A hybridoma secreting an antibody specifically reacting on the SEL1L recombinant fragment was selected. This monoclonal antibody, named MSel1, recognizes the SEL1L protein by Western blotting, immunofluorescence and immunohistochemistry on normal and tumor cells. MSel1 is able to recognize SEL1L even on archival tumor specimens and is therefore particularly appropriate to study SEL1L involvement in tumor progression.
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Affiliation(s)
- R Orlandi
- Department of Experimental Oncology, Istituto Nazionale Tumori, Milan, Italy
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Folci A, Steinberger A, Lee B, Stanika R, Scheruebel S, Campiglio M, Ramprecht C, Pelzmann B, Hell JW, Obermair GJ, Heine M, Di Biase V. Molecular mimicking of C-terminal phosphorylation tunes the surface dynamics of Ca V1.2 calcium channels in hippocampal neurons. J Biol Chem 2017; 293:1040-1053. [PMID: 29180451 PMCID: PMC5777246 DOI: 10.1074/jbc.m117.799585] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Revised: 11/03/2017] [Indexed: 11/26/2022] Open
Abstract
L-type voltage-gated CaV1.2 calcium channels (CaV1.2) are key regulators of neuronal excitability, synaptic plasticity, and excitation-transcription coupling. Surface-exposed CaV1.2 distributes in clusters along the dendrites of hippocampal neurons. A permanent exchange between stably clustered and laterally diffusive extra-clustered channels maintains steady-state levels of CaV1.2 at dendritic signaling domains. A dynamic equilibrium between anchored and diffusive receptors is a common feature among ion channels and is crucial to modulate signaling transduction. Despite the importance of this fine regulatory system, the molecular mechanisms underlying the surface dynamics of CaV1.2 are completely unexplored. Here, we examined the dynamic states of CaV1.2 depending on phosphorylation on Ser-1700 and Ser-1928 at the channel C terminus. Phosphorylation at these sites is strongly involved in CaV1.2-mediated nuclear factor of activated T cells (NFAT) signaling, long-term potentiation, and responsiveness to adrenergic stimulation. We engineered CaV1.2 constructs mimicking phosphorylation at Ser-1700 and Ser-1928 and analyzed their behavior at the membrane by immunolabeling protocols, fluorescence recovery after photobleaching, and single particle tracking. We found that the phosphomimetic S1928E variant increases the mobility of CaV1.2 without altering the steady-state maintenance of cluster in young neurons and favors channel stabilization later in differentiation. Instead, mimicking phosphorylation at Ser-1700 promoted the diffusive state of CaV1.2 irrespective of the differentiation stage. Together, these results reveal that phosphorylation could contribute to the establishment of channel anchoring mechanisms depending on the neuronal differentiation state. Finally, our findings suggest a novel mechanism by which phosphorylation at the C terminus regulates calcium signaling by tuning the content of CaV1.2 at signaling complexes.
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Affiliation(s)
- Alessandra Folci
- From the Institute of Biophysics, Medical University of Graz, 8010 Graz, Austria
| | - Angela Steinberger
- From the Institute of Biophysics, Medical University of Graz, 8010 Graz, Austria
| | - Boram Lee
- the Department of Pharmacology, University of California, Davis, California 95616
| | - Ruslan Stanika
- the Department of Physiology and Medical Physics, Medical University of Innsbruck, 6020 Innsbruck, Austria, and
| | - Susanne Scheruebel
- From the Institute of Biophysics, Medical University of Graz, 8010 Graz, Austria
| | - Marta Campiglio
- the Department of Physiology and Medical Physics, Medical University of Innsbruck, 6020 Innsbruck, Austria, and
| | - Claudia Ramprecht
- From the Institute of Biophysics, Medical University of Graz, 8010 Graz, Austria
| | - Brigitte Pelzmann
- From the Institute of Biophysics, Medical University of Graz, 8010 Graz, Austria
| | - Johannes W Hell
- the Department of Pharmacology, University of California, Davis, California 95616
| | - Gerald J Obermair
- the Department of Physiology and Medical Physics, Medical University of Innsbruck, 6020 Innsbruck, Austria, and
| | - Martin Heine
- the Leibniz Institute for Neurobiology, 39118 Magdeburg, Germany
| | - Valentina Di Biase
- From the Institute of Biophysics, Medical University of Graz, 8010 Graz, Austria,
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Findeisen F, Campiglio M, Jo H, Abderemane-Ali F, Rumpf CH, Pope L, Rossen ND, Flucher BE, DeGrado WF, Minor DL. Stapled Voltage-Gated Calcium Channel (Ca V) α-Interaction Domain (AID) Peptides Act As Selective Protein-Protein Interaction Inhibitors of Ca V Function. ACS Chem Neurosci 2017; 8:1313-1326. [PMID: 28278376 PMCID: PMC5481814 DOI: 10.1021/acschemneuro.6b00454] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
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For many voltage-gated
ion channels (VGICs), creation of a properly functioning ion channel
requires the formation of specific protein–protein interactions
between the transmembrane pore-forming subunits and cystoplasmic accessory
subunits. Despite the importance of such protein–protein interactions
in VGIC function and assembly, their potential as sites for VGIC modulator
development has been largely overlooked. Here, we develop meta-xylyl (m-xylyl) stapled peptides that
target a prototypic VGIC high affinity protein–protein interaction,
the interaction between the voltage-gated calcium channel (CaV) pore-forming subunit α-interaction domain (AID) and
cytoplasmic β-subunit (CaVβ). We show using
circular dichroism spectroscopy, X-ray crystallography, and isothermal
titration calorimetry that the m-xylyl staples enhance
AID helix formation are structurally compatible with native-like AID:CaVβ interactions and reduce the entropic penalty associated
with AID binding to CaVβ. Importantly, electrophysiological
studies reveal that stapled AID peptides act as effective inhibitors
of the CaVα1:CaVβ interaction
that modulate CaV function in an CaVβ
isoform-selective manner. Together, our studies provide a proof-of-concept
demonstration of the use of protein–protein interaction inhibitors
to control VGIC function and point to strategies for improved AID-based
CaV modulator design.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - Daniel L. Minor
- Molecular Biophysics & Integrated Imaging Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
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Campiglio M, Flucher BE. STAC3 stably interacts through its C1 domain with Ca V1.1 in skeletal muscle triads. Sci Rep 2017; 7:41003. [PMID: 28112192 PMCID: PMC5253670 DOI: 10.1038/srep41003] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Accepted: 12/13/2016] [Indexed: 01/03/2023] Open
Abstract
The adaptor protein STAC3 is essential for skeletal muscle excitation-contraction (EC) coupling and a mutation in the STAC3 gene has been linked to a severe muscle disease, Native American myopathy (NAM). However the function of STAC3, its interaction partner, and the mode of interaction within the EC-coupling complex remained elusive. Here we demonstrate that STAC3 forms a stable interaction with the voltage-sensor of EC-coupling, CaV1.1, and that this interaction depends on a hitherto unidentified protein-protein binding pocket in the C1 domain of STAC3. While the NAM mutation does not affect the stability of the STAC3-CaV1.1 interaction, mutation of two crucial residues in the C1 binding pocket increases the turnover of STAC3 in skeletal muscle triads. Thus, the C1 domain of STAC3 is responsible for its stable incorporation into the CaV1.1 complex, whereas the SH3 domain containing the NAM mutation site may be involved in low-affinity functional interactions in EC-coupling.
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Affiliation(s)
- Marta Campiglio
- Department of Physiology and Medical Physics, Medical University of Innsbruck, 6020 Innsbruck, Austria
| | - Bernhard E Flucher
- Department of Physiology and Medical Physics, Medical University of Innsbruck, 6020 Innsbruck, Austria
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Stanika R, Campiglio M, Pinggera A, Lee A, Striessnig J, Flucher BE, Obermair GJ. Splice variants of the Ca V1.3 L-type calcium channel regulate dendritic spine morphology. Sci Rep 2016; 6:34528. [PMID: 27708393 PMCID: PMC5052568 DOI: 10.1038/srep34528] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Accepted: 09/15/2016] [Indexed: 01/13/2023] Open
Abstract
Dendritic spines are the postsynaptic compartments of glutamatergic synapses in the brain. Their number and shape are subject to change in synaptic plasticity and neurological disorders including autism spectrum disorders and Parkinson’s disease. The L-type calcium channel CaV1.3 constitutes an important calcium entry pathway implicated in the regulation of spine morphology. Here we investigated the importance of full-length CaV1.3L and two C-terminally truncated splice variants (CaV1.342A and CaV1.343S) and their modulation by densin-180 and shank1b for the morphology of dendritic spines of cultured hippocampal neurons. Live-cell immunofluorescence and super-resolution microscopy of epitope-tagged CaV1.3L revealed its localization at the base-, neck-, and head-region of dendritic spines. Expression of the short splice variants or deletion of the C-terminal PDZ-binding motif in CaV1.3L induced aberrant dendritic spine elongation. Similar morphological alterations were induced by co-expression of densin-180 or shank1b with CaV1.3L and correlated with increased CaV1.3 currents and dendritic calcium signals in transfected neurons. Together, our findings suggest a key role of CaV1.3 in regulating dendritic spine structure. Under physiological conditions it may contribute to the structural plasticity of glutamatergic synapses. Conversely, altered regulation of CaV1.3 channels may provide an important mechanism in the development of postsynaptic aberrations associated with neurodegenerative disorders.
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Affiliation(s)
- Ruslan Stanika
- Division of Physiology, Medical University Innsbruck, 6020 Innsbruck, Austria
| | - Marta Campiglio
- Division of Physiology, Medical University Innsbruck, 6020 Innsbruck, Austria
| | - Alexandra Pinggera
- Department of Pharmacology and Toxicology, University of Innsbruck, 6020 Innsbruck, Austria
| | - Amy Lee
- Department of Molecular Physiology and Biophysics, Otolaryngology Head-Neck Surgery, and Neurology, University of Iowa, Iowa City, IA 52242, USA
| | - Jörg Striessnig
- Department of Pharmacology and Toxicology, University of Innsbruck, 6020 Innsbruck, Austria
| | - Bernhard E Flucher
- Division of Physiology, Medical University Innsbruck, 6020 Innsbruck, Austria
| | - Gerald J Obermair
- Division of Physiology, Medical University Innsbruck, 6020 Innsbruck, Austria
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33
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Rzhepetskyy Y, Lazniewska J, Proft J, Campiglio M, Flucher BE, Weiss N. A Ca v3.2/Stac1 molecular complex controls T-type channel expression at the plasma membrane. Channels (Austin) 2016; 10:346-354. [PMID: 27149520 DOI: 10.1080/19336950.2016.1186318] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Low-voltage-activated T-type calcium channels are essential contributors to neuronal physiology where they play complex yet fundamentally important roles in shaping intrinsic excitability of nerve cells and neurotransmission. Aberrant neuronal excitability caused by alteration of T-type channel expression has been linked to a number of neuronal disorders including epilepsy, sleep disturbance, autism, and painful chronic neuropathy. Hence, there is increased interest in identifying the cellular mechanisms and actors that underlie the trafficking of T-type channels in normal and pathological conditions. In the present study, we assessed the ability of Stac adaptor proteins to associate with and modulate surface expression of T-type channels. We report the existence of a Cav3.2/Stac1 molecular complex that relies on the binding of Stac1 to the amino-terminal region of the channel. This interaction potently modulates expression of the channel protein at the cell surface resulting in an increased T-type conductance. Altogether, our data establish Stac1 as an important modulator of T-type channel expression and provide new insights into the molecular mechanisms underlying the trafficking of T-type channels to the plasma membrane.
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Affiliation(s)
- Yuriy Rzhepetskyy
- a Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic , Prague , Czech Republic
| | - Joanna Lazniewska
- a Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic , Prague , Czech Republic
| | - Juliane Proft
- a Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic , Prague , Czech Republic
| | - Marta Campiglio
- b Division of Physiology, Department of Physiology and Medical Physics, Medical University Innsbruck , Innsbruck , Austria
| | - Bernhard E Flucher
- b Division of Physiology, Department of Physiology and Medical Physics, Medical University Innsbruck , Innsbruck , Austria
| | - Norbert Weiss
- a Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic , Prague , Czech Republic
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Tagliabue E, Turdo F, Bianchi F, Sandri M, Forte L, Casalini P, Gasparini P, Agresti R, Triulzi T, Sozzi G, Campiglio M. Abstract P5-07-11: CDCP1 as a new marker of aggressiveness in triple-negative breast cancers. Cancer Res 2016. [DOI: 10.1158/1538-7445.sabcs15-p5-07-11] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
Triple-negative breast cancer (TNBC) is an aggressive breast cancer subtype with high recurrences and mortality rate, for which no therapies besides chemotherapy are available to date. Lacking specific markers for an effective targeted therapy, TNBCs continue to represent the most important challenge for clinical oncologists. Here, we investigated the expression of CDCP1, a transmembrane non-catalytic receptor reportedly associated with poor prognosis in some solid tumors (e.g., lung and pancreatic cancer), and its association with tumor aggressiveness in a cohort of 115 human TNBC primary specimens obtained from women surgically treated in our Institute from the beginning of 2002 to the end of 2006 and selected based on immunohistochemical (IHC) criteria (<1% cell positivity for estrogen receptor, progesterone receptor and HER2 expression classified as 0 or 1+). CDCP1 was overexpressed in 56.5% of human primary TNBCs. FISH analysis of 75 TNBCs for which material was available delineated four different genetic categories: 1) disomic, with only two copies of CDCP1 and centromere (CDCP1<3, CEP3<3) (50/75, 67%); 2) amplified CDCP1 (CDCP1 ≥3, CEP3<3) (4/75, 5%); 3) polysomic CDCP1 (CDCP1≥3, CEP3≥3) (15/75, 20%); and 4) CDCP1 deleted of its centromere (CDCP1<3 CEP3≥3) (6/75, 8%). FISH positivity (polysomy or amplification) was significantly associated with IHC positivity (p=0.003). Permutation accuracy variable importance estimated by Random Survival Forests identified both CDCP1 protein expression and FISH positivity for CDCP1 as prognostic factors for DFS (HR=2.67, 95%CI 1.25-5.71, and HR= 2.95, 95%CI 1.33-6.53, respectively) and DDFS (HR=2.40, 95%CI 1.01-5.73, and HR= 3.40, 95%CI 1.44-8.04, respectively), together with age, lymph node involvement, tumor size, DCIS and Ki67 expression. Multivariate Cox survival analysis revealed a synergistic interaction between CDCP1 FISH/IHC status and N-status in DFS and DDFS. Indeed, while the 5-year relapse probability in N-negative patients did not differ according to CDCP1 IHC expression in tumor cells (18% and 13% in CDCP1 IHC negative and positive, respectively), the probability of developing distant metastases at 5 years of follow-up was 82% in N-positive/CDCP1 IHC-positive patients versus only 29% in N-positive/CDCP1 IHC-negative patients. Similarly, the probability of developing distant metastases at 5 years in the N-positive subgroup was 88% for CDCP1 FISH-positive versus 35% for CDCP1 FISH-negative patients, but only 16% and 14% in N-negative/CDCP1 FISH negative and positive, respectively.
Together, our results strongly suggest that CDCP1 is a marker of aggressiveness able to identify cases with poorer prognosis among N-positive TNBCs and, noticeably, overexpression of CDCP1 in human primary TNBCs can reflect a CDCP1 genetic gain.
Supported by AIRC.
Citation Format: Tagliabue E, Turdo F, Bianchi F, Sandri M, Forte L, Casalini P, Gasparini P, Agresti R, Triulzi T, Sozzi G, Campiglio M. CDCP1 as a new marker of aggressiveness in triple-negative breast cancers. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P5-07-11.
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Affiliation(s)
- E Tagliabue
- Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy; Fondazione IRCCS Istituto Nazionale dei Tumori
| | - F Turdo
- Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy; Fondazione IRCCS Istituto Nazionale dei Tumori
| | - F Bianchi
- Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy; Fondazione IRCCS Istituto Nazionale dei Tumori
| | - M Sandri
- Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy; Fondazione IRCCS Istituto Nazionale dei Tumori
| | - L Forte
- Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy; Fondazione IRCCS Istituto Nazionale dei Tumori
| | - P Casalini
- Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy; Fondazione IRCCS Istituto Nazionale dei Tumori
| | - P Gasparini
- Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy; Fondazione IRCCS Istituto Nazionale dei Tumori
| | - R Agresti
- Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy; Fondazione IRCCS Istituto Nazionale dei Tumori
| | - T Triulzi
- Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy; Fondazione IRCCS Istituto Nazionale dei Tumori
| | - G Sozzi
- Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy; Fondazione IRCCS Istituto Nazionale dei Tumori
| | - M Campiglio
- Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy; Fondazione IRCCS Istituto Nazionale dei Tumori
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Folci A, Steinberger A, Stanika R, Campiglio M, Ramprecht C, Obermair GJ, Heine M, Di Biase V. Molecular Mimicking of Phosphorylation at S1928 and S1700-T1704 Confers Modified Surface Traffic Properties to CaV1.2 Voltage Gated Calcium Channels in Cultured Hippocampal Neurons. Biophys J 2016. [DOI: 10.1016/j.bpj.2015.11.2379] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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Campiglio M, Flucher BE. The role of auxiliary subunits for the functional diversity of voltage-gated calcium channels. J Cell Physiol 2015; 230:2019-31. [PMID: 25820299 PMCID: PMC4672716 DOI: 10.1002/jcp.24998] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2015] [Accepted: 03/23/2015] [Indexed: 11/18/2022]
Abstract
Voltage-gated calcium channels (VGCCs) represent the sole mechanism to convert membrane depolarization into cellular functions like secretion, contraction, or gene regulation. VGCCs consist of a pore-forming α1 subunit and several auxiliary channel subunits. These subunits come in multiple isoforms and splice-variants giving rise to a stunning molecular diversity of possible subunit combinations. It is generally believed that specific auxiliary subunits differentially regulate the channels and thereby contribute to the great functional diversity of VGCCs. If auxiliary subunits can associate and dissociate from pre-existing channel complexes, this would allow dynamic regulation of channel properties. However, most auxiliary subunits modulate current properties very similarly, and proof that any cellular calcium channel function is indeed modulated by the physiological exchange of auxiliary subunits is still lacking. In this review we summarize available information supporting a differential modulation of calcium channel functions by exchange of auxiliary subunits, as well as experimental evidence in support of alternative functions of the auxiliary subunits. At the heart of the discussion is the concept that, in their native environment, VGCCs function in the context of macromolecular signaling complexes and that the auxiliary subunits help to orchestrate the diverse protein–protein interactions found in these calcium channel signalosomes. Thus, in addition to a putative differential modulation of current properties, differential subcellular targeting properties and differential protein–protein interactions of the auxiliary subunits may explain the need for their vast molecular diversity. J. Cell. Physiol. 999: 00–00, 2015. © 2015 The Authors. Journal of Cellular Physiology Published by Wiley Periodicals, Inc. J. Cell. Physiol. 230: 2019–2031, 2015. © 2015 Wiley Periodicals, Inc.
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Affiliation(s)
- Marta Campiglio
- Division of Physiology, Department of Physiology and Medical Physics, Medical University Innsbruck, Innsbruck, Austria
| | - Bernhard E Flucher
- Division of Physiology, Department of Physiology and Medical Physics, Medical University Innsbruck, Innsbruck, Austria
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Etemad S, Campiglio M, Obermair GJ, Flucher BE. The juvenile myoclonic epilepsy mutant of the calcium channel β(4) subunit displays normal nuclear targeting in nerve and muscle cells. Channels (Austin) 2015; 8:334-43. [PMID: 24875574 PMCID: PMC4203735 DOI: 10.4161/chan.29322] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Voltage-gated calcium channels regulate gene expression by controlling calcium entry through the plasma membrane and by direct interactions of channel fragments and auxiliary β subunits with promoters and the epigenetic machinery in the nucleus. Mutations of the calcium channel β4 subunit gene (CACNB4) cause juvenile myoclonic epilepsy in humans and ataxia and epileptic seizures in mice. Recently a model has been proposed according to which failed nuclear translocation of the truncated β4 subunit R482X mutation resulted in altered transcriptional regulation and consequently in neurological disease. Here we examined the nuclear targeting properties of the truncated β4b(1–481) subunit in tsA-201 cells, skeletal myotubes, and in hippocampal neurons. Contrary to expectation, nuclear targeting of β4b(1–481) was not reduced compared with full-length β4b in any one of the three cell systems. These findings oppose an essential role of the β4 distal C-terminus in nuclear targeting and challenge the idea that the nuclear function of calcium channel β4 subunits is critically involved in the etiology of epilepsy and ataxia in patients and mouse models with mutations in the CACNB4 gene.
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Campiglio M, Sandri M, Sasso M, Bianchi F, Balsari A, Ménard S, Tagliabue E. Prognostic role of tumor size in T1 HER2-positive breast cancers treated with adjuvant trastuzumab. Ann Oncol 2014; 25:1073-4. [PMID: 24558025 DOI: 10.1093/annonc/mdu058] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- M Campiglio
- Molecular Targeting Unit, Department of Experimental Oncology and Molecular Medicine, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan
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Triulzi T, De Cecco L, Giussani M, Canevari S, Carcangiu ML, Menard S, Campiglio M, Tagliabue E. Abstract P4-12-03: Role of primary tumor molecular characteristics in identifying relapses in HER2-positive breast carcinomas adjuvantly treated with trastuzumab. Cancer Res 2013. [DOI: 10.1158/0008-5472.sabcs13-p4-12-03] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
Trastuzumab, a recombinant humanized monoclonal antibody directed to the HER2 protein, has shown survival benefits in women with HER2-positive breast cancer, and treatment is now FDA-approved in combination with chemotherapy. Nonetheless, some patients relapse after treatment, underscoring the need to identify patients for whom chemotherapy + trastuzumab is adequate versus patients requiring additional drugs. To search for factors predictive of relapse in HER2-positive breast carcinoma patients treated adjuvantly with trastuzumab, we conducted gene expression profiling analysis in 53 cases selected among a cohort of 243 patients (32 of whom relapsed) treated in the clinic with chemotherapy + trastuzumab in our institute during 2006-2009, with median follow-up of 32 months; the 53 cases comprised 23 of the relapsed and 30 of the non-relapsed patients with similar clinico-pathological characteristics (size, lymph node involvement and estrogen receptor positivity) for whom sufficient material was available. RNA extracted from formalin-fixed, paraffin-embedded (FFPE) was profiled using HumanHT12_v4 wgDASL expression BeadChips (Illumina). A Cox's proportional hazard model was used to estimate the association between gene expression and relapse-free survival (RFS), and a multivariate permutation test was used to check the proportion of false discoveries. Analysis identified 330 probes corresponding to 308 unique genes as significantly associated to RFS (a<0.005; permutation test p<0.01), showing an enrichment for gene ontology biological processes such as cell cycle regulation of immune cell proliferation and activation, cytoskeleton organization, ER pathway and ion transport.
We also tested the feasibility of developing a predictive model including the gene expression data. Based on 10-fold cross-validation, our model was able to stratify patients into two groups (high and low risk), with a 4-year RFS probability of 14.5% in high-risk versus 87% in low-risk tumors (HR = 8.33, 95% CI = 3.53-18.18, p<0.0001). To test whether this signature identifies patients with intrinsic poor prognosis independent of trastuzumab treatment, we conducted in silico analysis on a dataset containing 144 HER2-positive breast carcinomas treated with chemotherapy alone; results revealed an inverse association between risk groups and prognosis, with an overall survival probability of 83% in our high-risk group and 63% in the low-risk group (HR = 0.60, 95% CI = 0.37-0.94, p = 0.0249).
Together, our results suggest the usefulness of molecular characteristics of primary tumors as indicators of early relapse in patients treated adjuvantly with trastuzumab and as tools to identify patients for whom additional treatments are required.
Supported by AIRC.
Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P4-12-03.
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Affiliation(s)
- T Triulzi
- Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy; Functional Genomics Core Facility, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy
| | - L De Cecco
- Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy; Functional Genomics Core Facility, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy
| | - M Giussani
- Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy; Functional Genomics Core Facility, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy
| | - S Canevari
- Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy; Functional Genomics Core Facility, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy
| | - ML Carcangiu
- Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy; Functional Genomics Core Facility, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy
| | - S Menard
- Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy; Functional Genomics Core Facility, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy
| | - M Campiglio
- Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy; Functional Genomics Core Facility, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy
| | - E Tagliabue
- Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy; Functional Genomics Core Facility, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy
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Campiglio M, Sandri M, Sasso M, Bianchi F, Turdo F, Ménard S, Tagliabue E. Abstract P4-12-06: Small HER2-positive breast carcinomas: Prognostic factors to consider in deciding on adjuvant trastuzumab treatment. Cancer Res 2013. [DOI: 10.1158/0008-5472.sabcs13-p4-12-06] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
Criteria for the decision to treat small tumors in adjuvant setting remain debatable, especially for HER2-positive tumors, since HER2 itself is associated with poor prognosis. Analysis of a large database including 503 T1 HER2-positive breast carcinomas treated with chemotherapy plus trastuzumab in Italian oncology clinics from 2006 to 2009 and, with 32 months of median follow-up and with 35 (7.0%) relapses, revealed no statistically significant differences in relapse rate among the T1a/T1micro, T1b and T1c groups, suggesting that tumor size is not associated with relapse probability in T1 HER2-positive tumors; the only clinico-pathological factors significantly associated with disease-free survival were nodal involvement (unadjusted HR = 3.4, 95%CI = 1.6-7.3, p = 0.002), loss of hormone receptor expression (HR = 3.1, 95%CI = 1.5-6.2, p = 0.002) and high tumor grade (HR = 2.9, 95%CI = 1.2-6.9, p = 0.020). Multivariate analysis indicated that patients who were both ER-negative and lymph node-positive presented the highest risk of relapse (HR = 5.5, 95%CI = 2.8-10.9, p = <0.001). These results suggest that the clinical decision for adjuvant treatment of small HER2-positive tumors should be based on nodal and hormone status, not on tumor size information. While the most recent National Comprehensive Cancer Network guidelines (version 3.2012) for systemic adjuvant treatment of small HER2-positive breast cancer only suggest considering adjuvant chemotherapy treatment including trastuzumab for T1a cases with axillary node micrometastasis and for all T1b, but require such treatment for all tumors >1 cm, our data identify T1 tumor ER-negativity/axillary lymph node-positivity as the crucial criteria for adjuvant treatment, independent of tumor size categories.
Supported by AIRC.
Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P4-12-06.
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Affiliation(s)
- M Campiglio
- Fondazione IRCCS-Istituto Nazionale dei Tumori, Milan, Italy
| | - M Sandri
- Fondazione IRCCS-Istituto Nazionale dei Tumori, Milan, Italy
| | - M Sasso
- Fondazione IRCCS-Istituto Nazionale dei Tumori, Milan, Italy
| | - F Bianchi
- Fondazione IRCCS-Istituto Nazionale dei Tumori, Milan, Italy
| | - F Turdo
- Fondazione IRCCS-Istituto Nazionale dei Tumori, Milan, Italy
| | - S Ménard
- Fondazione IRCCS-Istituto Nazionale dei Tumori, Milan, Italy
| | - E Tagliabue
- Fondazione IRCCS-Istituto Nazionale dei Tumori, Milan, Italy
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Campiglio M, Bufalino R, Sasso M, Ferri E, Casalini P, Adamo V, Fabi A, Aiello R, Riccardi F, Valle E, Scotti V, Tabaro G, Giuffrida D, Tarenzi E, Bologna A, Mustacchi G, Bianchi F, Balsari A, Ménard S, Tagliabue E. Effect of adjuvant trastuzumab treatment in conventional clinical setting: an observational retrospective multicenter Italian study. Breast Cancer Res Treat 2013; 141:101-10. [PMID: 23942848 PMCID: PMC3758836 DOI: 10.1007/s10549-013-2658-z] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2013] [Accepted: 07/30/2013] [Indexed: 01/03/2023]
Abstract
Clinical trials have shown the efficacy of trastuzumab-based adjuvant therapy in HER2-positive breast cancers, but routine clinical use awaits evaluation of compliance, safety, and effectiveness. Adjuvant trastuzumab-based therapy in routine clinical use was evaluated in the retrospective study GHEA, recording 1,002 patients treated according to the HERA protocol between March 2005 and December 2009 in 42 Italian oncology departments; 874 (87.23 %) patients completed 1-year trastuzumab treatment. In 128 patients (12.77 %), trastuzumab was withdrawn due to cardiac or non-cardiac toxicity (28 and 29 patients, respectively), disease progression (5 patients) or the clinician's decision (66 patients). In addition, 156 patients experienced minor non-cardiac toxicities; 10 and 44 patients showed CHF and decreased LVEF, respectively, at the end of treatment. Compliance and safety of adjuvant trastuzumab-based therapy in Italian hospitals were high and close to those reported in the HERA trial. With a median follow-up of 32 months, 107 breast cancer relapses were recorded (overall frequency, 10.67 %), and lymph node involvement, estrogen receptor negativity, lymphoid infiltration, and vascular invasion were identified as independent prognostic factors for tumor recurrence, indicating that relapses were associated with advanced tumor stage. Analysis of site and frequency of distant metastases showed that bone metastases were significantly more frequent during or immediately after trastuzumab (<18 months from the start of treatment) compared to recurrences in bone after the end of treatment and wash-out of the drug (>18 months from the start of treatment) (35.89 vs. 14.28 %, p = 0.0240); no significant differences were observed in recurrences in the other recorded body sites, raising the possibility that the protection exerted by trastuzumab is lower in bone metastases.
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Affiliation(s)
- M Campiglio
- Molecular Targeting Unit, Department of Experimental Oncology and Molecular Medicine, Fondazione IRCCS Istituto Nazionale dei Tumori, Via Amadeo 42, 20133 Milan, Italy.
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Campiglio M, Di Biase V, Tuluc P, Flucher BE. Stable incorporation versus dynamic exchange of β subunits in a native Ca2+ channel complex. J Cell Sci 2013; 126:2092-101. [PMID: 23447673 DOI: 10.1242/jcs.jcs124537] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Voltage-gated Ca(2+) channels are multi-subunit membrane proteins that transduce depolarization into cellular functions such as excitation-contraction coupling in muscle or neurotransmitter release in neurons. The auxiliary β subunits function in membrane targeting of the channel and modulation of its gating properties. However, whether β subunits can reversibly interact with, and thus differentially modulate, channels in the membrane is still unresolved. In the present study we applied fluorescence recovery after photobleaching (FRAP) of GFP-tagged α1 and β subunits expressed in dysgenic myotubes to study the relative dynamics of these Ca(2+) channel subunits for the first time in a native functional signaling complex. Identical fluorescence recovery rates of both subunits indicate stable interactions, distinct recovery rates indicate dynamic interactions. Whereas the skeletal muscle β1a isoform formed stable complexes with CaV1.1 and CaV1.2, the non-skeletal muscle β2a and β4b isoforms dynamically interacted with both α1 subunits. Neither replacing the I-II loop of CaV1.1 with that of CaV2.1, nor deletions in the proximal I-II loop, known to change the orientation of β relative to the α1 subunit, altered the specific dynamic properties of the β subunits. In contrast, a single residue substitution in the α interaction pocket of β1aM293A increased the FRAP rate threefold. Taken together, these findings indicate that in skeletal muscle triads the homologous β1a subunit forms a stable complex, whereas the heterologous β2a and β4b subunits form dynamic complexes with the Ca(2+) channel. The distinct binding properties are not determined by differences in the I-II loop sequences of the α1 subunits, but are intrinsic properties of the β subunit isoforms.
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Affiliation(s)
- Marta Campiglio
- Department of Physiology and Medical Physics, Medical University Innsbruck, A-6020 Innsbruck, Austria
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Campiglio M, Di Biase V, Tuluc P, Flucher BE. Dynamics of Homologous and Heterologous Calcium Channel α1 and β Subunits in the Skeletal Muscle Triad. Biophys J 2012. [DOI: 10.1016/j.bpj.2011.11.318] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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Campiglio M, Sasso M, Bianchi F, Plantamura I, Iorio M, De Cecco L, Giustarini E, Agresti R, Ghirelli C, Cremona M, Tripodo C, Tagliabue E. PD08-07: Wound-Healing Drainage Fluids Promote Triple Negative Breast Cancer Progression. Cancer Res 2011. [DOI: 10.1158/0008-5472.sabcs11-pd08-07] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
Triple negative breast cancers (TNBC) account for 15% of breast cancers. TNBCs carry a high risk of recurrence and deaths, due to the high rate of local and systemic relapse in these patients and no therapeutic options except chemotherapy are currently available. The TNBC pattern of recurrence present a distant recurrence peak at approximately 3 years and then declines rapidly thereafter, whereas in all non-TNBC types the recurrence risk seems to be constant over time. TNBC relapse risk is comparable to that of HER2−positive tumors subtype, in which growth-factors released during the healing process accelerate the early recurrences in HER2−positive patients. Thus, we speculate that also TNBC early relapse may depend on their capability to respond to wound-healing stimulation. To this aim, TNBC were treated with drainages to identify which receptors/pathways can be activated and play a driving role in TNBC progression. A pilot reverse phase protein microarray (RPMA) experiment on MDA-MB-231 TN cells drainage-fluids stimulated revealed a specific activation of PDGFR and VEGFR and their downstream pathways, whereas no significant changes were observed in other receptors, such as EGFR, IRS, Met and ERB3. The type of activated receptors suggested the involvement of endothelial receptors upon drainages stimulation and, indeed TNBC cell lines expressed endothelial molecules, such as CD34, CD31, CD146. Beside the proved role of some of these receptors in cellular proliferation, the TNBC endothelial-like phenotype prompt us to analyzed TNBC cell lines capability to form vascular-like channels when seeded on matrigel. Drainages were able to accelerate the formation of vascular channels in TNBC cell lines and, moreover to consistently increase proliferation of TNBC cells compared to non-TNBC cells. To prove whether receptors found activated by drainages play a key role in TNBC progression, we targeted PDGFR, VEGFR and other receptors possibly involved in angiogenesis and vasculogenic mimicry with sunitinib (targeting PDGFR, VEGFR, FGF and c-kit), anti-bFGF antibody (Ab)(targeting the ligand bFGF) and bevacizumab (targeting the VEGF) in TNBC cells drainage-stimulated in vitro. Sunitinib and anti-bFGF Ab halved the proliferation of TNBC cell lines and reduced of almost 60% the formation of vascular-like channels in TNBC cells, whereas bevacizumab modestly affect proliferation but not vasculogenic properties. Notably, sunitinib and anti-bFGF Ab strongly inhibited MDA-MB-231 and MDA-MB-468 xenografts tumor growth (sunitinib: 80%, and 70% Growth Index (GI), respectively; anti-bFGF Ab 70% and 60% GI, respectively) whereas bevacizumab determined no more than 30% decrease of tumor volume. Unfortunately, all these drugs did not efficiently control the development of lung metastases, that indeed significant increased compared to their control, possibly through induction of hypoxia processes. In conclusion, wound healing promotes TNBC progression by sustaining proliferation and vasculogenesis. The use of sunitinib and anti-bFGF antibody strongly inhibited tumor growth in mice models, but significantly increased lung metastases suggesting a combined use of these drugs with molecules able to interfere with hypoxia pathway.
Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr PD08-07.
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Affiliation(s)
- M Campiglio
- 1Fondazione IRCCS-Istituto Nazionale Tumori, Milan, Italy; University of Palermo, Palermo, Italy
| | - M Sasso
- 1Fondazione IRCCS-Istituto Nazionale Tumori, Milan, Italy; University of Palermo, Palermo, Italy
| | - F Bianchi
- 1Fondazione IRCCS-Istituto Nazionale Tumori, Milan, Italy; University of Palermo, Palermo, Italy
| | - I Plantamura
- 1Fondazione IRCCS-Istituto Nazionale Tumori, Milan, Italy; University of Palermo, Palermo, Italy
| | - M Iorio
- 1Fondazione IRCCS-Istituto Nazionale Tumori, Milan, Italy; University of Palermo, Palermo, Italy
| | - L De Cecco
- 1Fondazione IRCCS-Istituto Nazionale Tumori, Milan, Italy; University of Palermo, Palermo, Italy
| | - E Giustarini
- 1Fondazione IRCCS-Istituto Nazionale Tumori, Milan, Italy; University of Palermo, Palermo, Italy
| | - R Agresti
- 1Fondazione IRCCS-Istituto Nazionale Tumori, Milan, Italy; University of Palermo, Palermo, Italy
| | - C Ghirelli
- 1Fondazione IRCCS-Istituto Nazionale Tumori, Milan, Italy; University of Palermo, Palermo, Italy
| | - M Cremona
- 1Fondazione IRCCS-Istituto Nazionale Tumori, Milan, Italy; University of Palermo, Palermo, Italy
| | - C Tripodo
- 1Fondazione IRCCS-Istituto Nazionale Tumori, Milan, Italy; University of Palermo, Palermo, Italy
| | - E Tagliabue
- 1Fondazione IRCCS-Istituto Nazionale Tumori, Milan, Italy; University of Palermo, Palermo, Italy
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Adamo V, Ricciardi GRR, Adamo B, Agostara B, Caruso M, Gebbia V, Gebbia N, Lavenia G, Banna GL, Mafodda A, Rossello R, Butera A, Spada S, Borsellino N, Mangiameli A, Campiglio M, Tuccari G. Observational study to evaluate the pattern of trastuzumab (T) use and survival outcomes in HER2-positive (HER2+) early breast cancer (EBC): Regional Southern Italy experience. J Clin Oncol 2011. [DOI: 10.1200/jco.2011.29.15_suppl.e11043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Campiglio M, Tagliabue E, Balsari A, Bufalino R, Ferri E, Gianni L, Ménard S. Protection of adjuvant trastuzumab in sites of early relapses. J Clin Oncol 2011. [DOI: 10.1200/jco.2011.29.15_suppl.619] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Tagliabue E, Plantamura I, Iorio MV, Dugnani E, Tortoreto M, Ghirelli C, Barajon I, Arnaboldi F, Triulzi T, Casalini P, Agresti R, Campiglio M, Balsari A. Abstract P6-08-01: Endothelial-Like Phenotype of Triple-Negative Breast Carcinoma Cells and Implications for New Molecular Targets. Cancer Res 2010. [DOI: 10.1158/0008-5472.sabcs10-p6-08-01] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
Background. Triple Negative Breast Cancers (TNBCs) still represent a question mark in breast cancer biology and a primary issue in clinics. A promising approach for an efficient targeted treatment of TNBCs seems to be represented by antiangiogenic therapies.
Methods. Effects of different compounds on proliferation of TNBC was evaluated in vivo and in vitro respectively by xenograft tumor volume analysis and SRB assay. Vasculogenic Mimicry (VM) properties were evaluated in vitro and in vivo respectively by tube formation assay and Transmission Electron Microscopy (TEM).
Results. Treatment of triple negative (TN) MDA-MB-231 xenografts with Sunitinib induced tumor regression, versus only a slight growth inhibition in tumors derived from MCF7 luminal cell line, whereas Bevacizumab determined only a modest decrease in tumor growth in both models. Accordingly, the efficacy of Sunitinib in blocking in vitro growth of breast cancer cell lines was higher in MDA-MB-231 cells in comparison with MCF7 cells (IC50 at 72h in MDA-MB-231 was 5 uM vs 25 uM in MCF7, as evaluated by SRB), and sensitivity to Bevacizumab was comparable between the two different cell lines. Investigating the undifferentiated nature of TNBCs, we observed that these tumors present an endothelial like phenotype and behavior, as supported respectively by the expression of endothelial markers, and the formation of vascular-like channels in vitro. In fact, all six TN cell lines evaluated (MDA-MB-231, MDA-MB-157, MDA-MB-468, BT-549, BT-20 and HCC1937) were able to form vascular channels when seeded on the murine tumor-derived basement membrane (Matrigel), whereas luminal (MCF7, T47D and ZR-75-1) and HER2- positive (MDA-MB-361, BT474 and SKBr3) breast carcinoma cell lines did not exhibit vascular structures. Then, we evaluated the VM in xenograft tumors derived from MDA-MB-231, MCF7 and MDA-MB-361 using transmission electron microscopy (TEM). MDA-MB-231 xenografts displayed channel-like structures formed by tumor cells encompassing erytrocytes, whereas in MCF7 and MDA-MB-361 xenografts the endothelial lining delimiting blood vessels was clearly visible. Notably, blood vessels surrounded by tumor cells were also identified in human TN specimens processed for TEM, and these structures were significantly more frequent in TN compared to non-TN tumors. 60% reduction in TN vascular channel formation in vitro by an anti-bFGF monoclonal antibody along with no effect using anti-VEGF antibody indicated that TN breast carcinoma cells can generate vascular channels through bFGF-mediated pathway. Silencing of different receptors involved in bFGF signal (i.e. FGFR2 and PDGFR β) abrogated VM in TN cells. Finally, TNBC cells able to perform vascular-like channels were found to express significantly higher (p= 0.003) levels of FGFR related genes, described associated with basal-like BC aggressiveness, compared to all the other tested cell lines. Conclusions. Our findings point to the possibility that TNBC cells are maintained by proangiogenic signals and that increased sensitivity to Sunitinib probably relies on the specific impairment of PDGFRβ and FGFR2-mediated pathways, which might represent a possible specific therapeutic target. Partially supported by AIRC and Italian Bureau of Health.
Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P6-08-01.
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Affiliation(s)
- E Tagliabue
- Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy; University of Milan, Italy
| | - I Plantamura
- Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy; University of Milan, Italy
| | - MV Iorio
- Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy; University of Milan, Italy
| | - E Dugnani
- Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy; University of Milan, Italy
| | - M Tortoreto
- Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy; University of Milan, Italy
| | - C Ghirelli
- Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy; University of Milan, Italy
| | - I Barajon
- Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy; University of Milan, Italy
| | - F Arnaboldi
- Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy; University of Milan, Italy
| | - T Triulzi
- Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy; University of Milan, Italy
| | - P Casalini
- Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy; University of Milan, Italy
| | - R Agresti
- Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy; University of Milan, Italy
| | - M Campiglio
- Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy; University of Milan, Italy
| | - A. Balsari
- Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy; University of Milan, Italy
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Campiglio M, Tagliabue E, Balsari A, Bufalino R, Ferri E, Ménard S. Observational GHEA study: Adjuvant trastuzumab treatment of HER2-positive breast carcinomas in the Italian clinical setting compared to HERA trial. J Clin Oncol 2010. [DOI: 10.1200/jco.2010.28.15_suppl.672] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Campiglio M, Tagliabue E, Balsari A, Bufalino R, Ferri E, Menard S. Observational GHEA Study: Adjuvant-Trastuzumab-Treatment of HER2-Positive Breast Carcinoma. Cancer Res 2009. [DOI: 10.1158/0008-5472.sabcs-09-5112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
Background: GHEA (Group HErceptin in Adiuvant treatment), an Italian multicentric observational study, was designed with the aim to investigate on adjuvant trastuzumab-therapy of HER2-positive breast carcinomas in conventional clinical setting.Material and Methods: Eligible patients should have been treated with trastuzumab in adjuvant setting and were collected among 35 oncologic Italian centers.Results: The patient registered so far in the GHEA database (500 pts) had a median age of 52 years and 64% were in post-menopause at the time of trastuzumab therapy. Primary breast tumor were mainly of ductal type (93%) of high grade (59% were GIII) and small in size (58% T1, 35% T2, 4% T3 and 3% T4). 12% of the samples included in GHEA were classified as T1micro, T1a and T1b, three categories generally not included in clinical trials. ER and PgR positive tumors were 58% and 51%, respectively and more than 53% presented in situ component. Positive lymph-nodes were present in 53% of cases. 15% of the patients received neo-adjuvant therapy prior surgery and adjuvant treatment. In the neo-adjuvant therapy, 95% of patients received anthracycline–based regimens and 72% were treated with taxanes. In adjuvant setting 89% of patients received anthracycline–based regimens and only 43% were treated with taxanes. 88% of the patients completed 1-year-trastuzumab treatment. Median exposure time of the series was 26 months. To date, 6% of the patients presented distant metastasis (i.e. bones, liver, lung, SNC) and half of them progressed during trastuzumab treatment.Discussion: The purpose of the present study is to gather information from a large number of patients related to the effect of adjuvant trastuzumab treatment in conventional clinical setting, the treatment of tumor categories not included in clinical trails and the therapies used at the relapse of these patients. All together, these data are warranted to design further clinical trials to better define guide-line for trastuzumab adjuvant therapy and for the treatment of these patients at relapse.Supported by AIRC and Roche.
Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 5112.
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Affiliation(s)
- M. Campiglio
- 1Fondazione IRCCS Istituto Nazionale dei Tumori, Italy
| | - E. Tagliabue
- 1Fondazione IRCCS Istituto Nazionale dei Tumori, Italy
| | - A. Balsari
- 2Dipartimento di Morfologia Umana e Scienze Biomediche “Città Studi”, Università degli Studi di Milano, Italy
| | - R. Bufalino
- 1Fondazione IRCCS Istituto Nazionale dei Tumori, Italy
| | - E. Ferri
- 1Fondazione IRCCS Istituto Nazionale dei Tumori, Italy
| | - S. Menard
- 1Fondazione IRCCS Istituto Nazionale dei Tumori, Italy
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Bianchi F, Campiglio M, Sasso M, Ghirelli C, Tagliabue E, Cairo G, Salvatorelli E, Minotti G, Menna P, Ménard S. Increasing doxorubicin antitumor activity through COX-2 inhibition without increasing cardiotoxicity. EJC Suppl 2008. [DOI: 10.1016/s1359-6349(08)71295-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
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