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Ahmed AA, Farooqi MS, Habeebu SS, Gonzalez E, Flatt TG, Wilson AL, Barr FG. NanoString Digital Molecular Profiling of Protein and microRNA in Rhabdomyosarcoma. Cancers (Basel) 2022; 14:cancers14030522. [PMID: 35158790 PMCID: PMC8833805 DOI: 10.3390/cancers14030522] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Revised: 01/16/2022] [Accepted: 01/18/2022] [Indexed: 12/13/2022] Open
Abstract
Simple Summary NanoString digital profiling methods are novel techniques to identify biologic markers from human formalin-fixed, paraffin-embedded cancer tissue. We have applied NanoString Digital spatial profiling and microRNA profiling methods in non-alveolar rhabdomyosarcoma, a common soft tissue tumor in young adults and children with variable prognosis. Our results have highlighted aberrant miRNA expression and over-expression of several members of PI3-AKT, MAPK and apoptosis signaling pathways in fusion-negative rhabdomyosarcoma, particularly in tumors with unfavorable prognosis. INPP4B, an entry molecule in the PI3/AKT pathway, was significantly over-expressed in tumors with poor prognosis, confirmed by traditional immunohistochemistry. Several microRNAs had increased expression in association with poor patient prognosis. These results highlight the utility of NanoString digital profiling as a screening method to identify prognostic biomarkers of interest in rhabdomyosarcoma from formalin-fixed paraffin-embedded tissue. Abstract Purpose: Rhabdomyosarcoma (RMS) exhibits a complex prognostic algorithm based on histologic, biologic and clinical parameters. The embryonal (ERMS) and spindle cell-sclerosing RMS (SRMS) histologic subtypes warrant further studies due to their heterogenous genetic background and variable clinical behavior. NanoString digital profiling methods have been previously highlighted as robust novel methods to detect protein and microRNA expression in several cancers but not in RMS. Methods/Patients: To identify prognostic biomarkers, we categorized 12 ERMS and SRMS tumor cases into adverse (n = 5) or favorable (n = 7) prognosis groups and analyzed their signaling pathways and microRNA profiles. The digital spatial profiling of protein and microRNA analysis was performed on formalin-fixed, paraffin-embedded (FFPE) tumor tissue using NanoString technology. Results: The detectable expression of several component members of the PI3K/AKT, MAPK and apoptosis signaling pathways was highlighted in RMS, including INPP4B, Pan-AKT, MET, Pan-RAS, EGFR, phospho-p90 RSK, p44/42 ERK1/2, BAD, BCL-XL, cleaved caspase-9, NF1, PARP and p53. Compared to cases with favorable prognosis, the adverse-prognosis tumor samples had significantly increased expression of INPP4B, which was confirmed with traditional immunohistochemistry. The analysis of microRNA profiles revealed that, out of 798 microRNAs assessed, 228 were overexpressed and 134 downregulated in the adverse prognosis group. Significant over-expression of oncogenic/tumor suppressor miR-3144-3p, miR-612, miR-302d-3p, miR-421, miR-548ar-5p and miR-548y (p < 0.05) was noted in the adverse prognosis group. Conclusion: This study highlights the utility of NanoString digital profiling methods in RMS, where it can detect distinct molecular signatures with the expression of signaling pathways and microRNAs from FFPE tumor tissue that may help identify prognostic biomarkers of interest. The overexpression of INPP4B and miR-3144-3p, miR-612, miR-302d-3p, miR-421, miR-548y and miR-548ar-5p may be associated with worse overall survival in ERMS and SRMS.
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Affiliation(s)
- Atif A. Ahmed
- Department of Pathology and Laboratory Medicine, Children’s Mercy Hospital, Kansas City, MO 64108, USA
- Department of Pathology and Laboratory Medicine, Children’s Mercy Hospital/University of Missouri, Kansas City, MO 64108, USA; (M.S.F.); (S.S.H.)
- Correspondence: ; Tel.: +1-816-234-3000
| | - Midhat S. Farooqi
- Department of Pathology and Laboratory Medicine, Children’s Mercy Hospital/University of Missouri, Kansas City, MO 64108, USA; (M.S.F.); (S.S.H.)
| | - Sultan S. Habeebu
- Department of Pathology and Laboratory Medicine, Children’s Mercy Hospital/University of Missouri, Kansas City, MO 64108, USA; (M.S.F.); (S.S.H.)
| | - Elizabeth Gonzalez
- Department of Pediatric Hematology-Oncology, Children’s Mercy Hospital/University of Missouri, Kansas City, MO 64108, USA; (E.G.); (T.G.F.)
| | - Terrie G. Flatt
- Department of Pediatric Hematology-Oncology, Children’s Mercy Hospital/University of Missouri, Kansas City, MO 64108, USA; (E.G.); (T.G.F.)
| | | | - Frederic G. Barr
- Laboratory of Pathology, National Cancer Institute, Bethesda, MD 20892, USA;
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Mennuni M, Filograna R, Felser A, Bonekamp NA, Giavalisco P, Lytovchenko O, Larsson N. Metabolic resistance to the inhibition of mitochondrial transcription revealed by CRISPR-Cas9 screen. EMBO Rep 2022; 23:e53054. [PMID: 34779571 PMCID: PMC8728608 DOI: 10.15252/embr.202153054] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Revised: 10/12/2021] [Accepted: 10/19/2021] [Indexed: 12/20/2022] Open
Abstract
Cancer cells depend on mitochondria to sustain their increased metabolic need and mitochondria therefore constitute possible targets for cancer treatment. We recently developed small-molecule inhibitors of mitochondrial transcription (IMTs) that selectively impair mitochondrial gene expression. IMTs have potent antitumor properties in vitro and in vivo, without affecting normal tissues. Because therapy-induced resistance is a major constraint to successful cancer therapy, we investigated mechanisms conferring resistance to IMTs. We employed a CRISPR-Cas9 (clustered regularly interspaced short palindromic repeats)-(CRISP-associated protein 9) whole-genome screen to determine pathways conferring resistance to acute IMT1 treatment. Loss of genes belonging to von Hippel-Lindau (VHL) and mammalian target of rapamycin complex 1 (mTORC1) pathways caused resistance to acute IMT1 treatment and the relevance of these pathways was confirmed by chemical modulation. We also generated cells resistant to chronic IMT treatment to understand responses to persistent mitochondrial gene expression impairment. We report that IMT1-acquired resistance occurs through a compensatory increase of mitochondrial DNA (mtDNA) expression and cellular metabolites. We found that mitochondrial transcription factor A (TFAM) downregulation and inhibition of mitochondrial translation impaired survival of resistant cells. The identified susceptibility and resistance mechanisms to IMTs may be relevant for different types of mitochondria-targeted therapies.
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Affiliation(s)
- Mara Mennuni
- Department of Medical Biochemistry and BiophysicsKarolinska InstitutetStockholmSweden
| | - Roberta Filograna
- Department of Medical Biochemistry and BiophysicsKarolinska InstitutetStockholmSweden
| | - Andrea Felser
- Department of Medical Biochemistry and BiophysicsKarolinska InstitutetStockholmSweden
- University Institute of Clinical ChemistryBern University HospitalBernSwitzerland
| | - Nina A Bonekamp
- Mitochondrial Biology GroupMax Planck Institute for Biology of AgeingCologneGermany
- Department of NeuroanatomyMannheim Center for Translational Neuroscience (MCTN)Medical Faculty MannheimHeidelberg UniversityMannheimGermany
| | - Patrick Giavalisco
- Metabolomics Core FacilityMax Planck Institute for Biology of AgeingCologneGermany
| | - Oleksandr Lytovchenko
- Department of Medical Biochemistry and BiophysicsKarolinska InstitutetStockholmSweden
| | - Nils‐Göran Larsson
- Department of Medical Biochemistry and BiophysicsKarolinska InstitutetStockholmSweden
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Deng L, Jiang L, Lin X, Tseng KF, Lu Z, Wang X. Luteolin, a novel p90 ribosomal S6 kinase inhibitor, suppresses proliferation and migration in leukemia cells. Oncol Lett 2017; 13:1370-1378. [PMID: 28454264 DOI: 10.3892/ol.2017.5597] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Accepted: 11/01/2016] [Indexed: 01/06/2023] Open
Abstract
Ribosomal S6 kinases (RSKs) are directly regulated by extracellular signal-regulated kinase (ERK) signaling and are implicated in cell growth, survival, motility and senescence. The present study observed that RSK1 was overexpressed in primary untreated leukemia patient bone marrow samples compared with the expression at the complete remission stage, using reverse transcription-quantitative polymerase chain reaction (RT-qPCR). In addition, a high RSK1 expression (relative expression ≥10) was associated with a significantly shorter overall survival (P=0.038) compared with that in patients with low RSK1 expression (relative expression <10). The current study also investigated the effect of luteolin, a novel p90 ribosomal S6 kinase (RSK) inhibitor extracted from Reseda odorata L., which shows strong biochemical functions including anti-allergy, anti-inflammation and anti-cancer functions, in MOLM-13 and Kasumi-1 leukemic cells. The cell viability, apoptosis and migration ability analysis were assessed by performing a cell counting kit-8 assay, Annexin V-FITC/PI double staining and migration filter assay, respectively. The results indicated that luteolin inhibited the growth of the leukemic cell lines through induction of apoptosis, while the migration ability was also suppressed. Overexpression of RSK1 by plasmid transfection was found to decrease the luteolin-induced apoptosis and migration capabilities. By contrast, knockdown of the RSK1 expression by small interfering RNA appeared to induce the same effect as luteolin on MOLM-13 and Kasumi-1 leukemic cells. In conclusion, these results suggest that luteolin inhibits leukemic cell proliferation and induces apoptosis by inhibition of the RSK1 pathways.
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Affiliation(s)
- Lan Deng
- Department of Hematology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, Guangdong 510120, P.R. China.,Department of Hematology, Zhujiang Hospital, Southern Medical University, Guangzhou, Guangdong 501282, P.R. China
| | - Ling Jiang
- Department of Hematology, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong 510515, P.R. China
| | - Xianghua Lin
- Department of Hematology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, Guangdong 510120, P.R. China
| | - Kuo-Fu Tseng
- Department of Biophysics, Oregon State University, Corvallis, OR 97330, USA
| | - Zhigang Lu
- Department of Hematology, Zhujiang Hospital, Southern Medical University, Guangzhou, Guangdong 501282, P.R. China
| | - Xiuju Wang
- Department of Hematology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, Guangdong 510120, P.R. China
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Beauvais DM, Jung O, Yang Y, Sanderson RD, Rapraeger AC. Syndecan-1 (CD138) Suppresses Apoptosis in Multiple Myeloma by Activating IGF1 Receptor: Prevention by SynstatinIGF1R Inhibits Tumor Growth. Cancer Res 2016; 76:4981-93. [PMID: 27364558 DOI: 10.1158/0008-5472.can-16-0232] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Accepted: 06/09/2016] [Indexed: 01/20/2023]
Abstract
Syndecan-1 (Sdc1/CD138) expression is linked to disease severity in multiple myeloma, although the causal basis for this link remains unclear. Here we report that capture of the IGF1 receptor (IGF1R) by Sdc1 suppresses ASK1-dependent apoptosis in multiple myeloma cells. Sdc1 binds two different fractions of IGF1R, one that is constitutively active and a second that is activated by IGF1 ligand. Notably, IGF1R kinase activity in both fractions is blocked by synstatinIGF1R (SSTNIGF1R), a peptide that inhibits IGF1R capture by Sdc1, as well as by a truncated peptide (SSTNIGF1R-T) that appears to be specific for multiple myeloma cells. Mechanistically, we show that ASK1 is bound to active IGF1R and inhibited by Tyr and Ser83/Ser966 phosphorylation. When IGF1R engagement with Sdc1 is blocked by SSTNIGF1R, ASK1 becomes activated, and initiates JNK- and caspase-3-mediated apoptosis. In pharmacologic tests, we find SSTNIGF1R is highly stable in human plasma and displays a half-life of 27 hours in mice, wherein it significantly reduces both the size and neovascularization of CAG myeloma tumor xenografts. Taken together, our results offer a preclinical proof of concept and mechanistic rationale for the exploration of SSTNIGF1R as an experimental therapeutic to dually attack multiple myeloma tumor cell survival and tumor angiogenesis. Cancer Res; 76(17); 4981-93. ©2016 AACR.
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Affiliation(s)
- DeannaLee M Beauvais
- Department of Human Oncology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin
| | - Oisun Jung
- Department of Human Oncology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin. The Graduate Program in Molecular and Cellular Pharmacology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin
| | - Yang Yang
- Department of Pathology and the University of Alabama at Birmingham Comprehensive Cancer Center, University of Alabama at Birmingham, Birmingham, Alabama
| | - Ralph D Sanderson
- Department of Pathology and the University of Alabama at Birmingham Comprehensive Cancer Center, University of Alabama at Birmingham, Birmingham, Alabama
| | - Alan C Rapraeger
- Department of Human Oncology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin. The Graduate Program in Molecular and Cellular Pharmacology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin. The University of Wisconsin Carbone Cancer Center, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin.
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Tengku Din TADAA, Seeni A, Khairi WNM, Shamsuddin S, Jaafar H. Effects of rapamycin on cell apoptosis in MCF-7 human breast cancer cells. Asian Pac J Cancer Prev 2015; 15:10659-63. [PMID: 25605156 DOI: 10.7314/apjcp.2014.15.24.10659] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Rapamycin is an effective anti-angiogenic drug. However, the mode of its action remains unclear. Therefore, in this study, we aimed to elucidate the antitumor mechanism of rapamycin, hypothetically via apoptotic promotion, using MCF-7 breast cancer cells. MATERIALS AND METHODS MCF-7 cells were plated at a density of 15105 cells/well in 6-well plates. After 24h, cells were treated with a series of concentrations of rapamycin while only adding DMEM medium with PEG for the control regiment and grown at 37oC, 5% CO2 and 95% air for 72h. Trypan blue was used to determine the cell viability and proliferation. Untreated and rapamycin-treated MCF-7 cells were also examined for morphological changes with an inverted-phase contrast microscope. Alteration in cell morphology was ascertained, along with a stage in the cell cycle and proliferation. In addition, cytotoxicity testing was performed using normal mouse breast mammary pads. RESULTS Our results clearly showed that rapamycin exhibited inhibitory activity on MCF-7 cell lines. The IC50 value of rapamycin on the MCF-7 cells was determined as 0.4μg/ml (p<0.05). Direct observation by inverted microscopy demonstrated that the MCF-7 cells treated with rapamycin showed characteristic features of apoptosis including cell shrinkage, vascularization and autophagy. Cells underwent early apoptosis up to 24% after 72h. Analysis of the cell cycle showed an increase in the G0G1 phase cell population and a corresponding decrease in the S and G2M phase populations, from 81.5% to 91.3% and 17.3% to 7.9%, respectively. CONCLUSIONS This study demonstrated that rapamycin may potentially act as an anti-cancer agent via the inhibition of growth with some morphological changes of the MCF-7 cancer cells, arrest cell cycle progression at G0/G1 phase and induction of apoptosis in late stage of apoptosis. Further studies are needed to further characterize the mode of action of rapamycin as an anti-cancer agent.
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da Costa MR, Pizzatti L, Lindoso RS, Sant'Anna JF, DuRocher B, Abdelhay E, Vieyra A. Mechanisms of kidney repair by human mesenchymal stromal cells after ischemia: a comprehensive view using label-free MS(E). Proteomics 2014; 14:1480-93. [PMID: 24723500 DOI: 10.1002/pmic.201300084] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2013] [Revised: 02/24/2014] [Accepted: 03/27/2014] [Indexed: 01/08/2023]
Abstract
Acute kidney injury (AKI) is one of the more frequent and lethal pathological conditions seen in intensive care units. Currently available treatments are not totally effective but stem cell-based therapies are emerging as promising alternatives, especially the use of mesenchymal stromal cells (MSC), although the signaling pathways involved in their beneficial actions are not fully understood. The objective of this study was to identify signaling networks and key proteins involved in the repair of ischemia by MSC. Using an in vitro model of AKI to investigate paracrine interactions and label-free high definition 2D-NanoESI-MS(E) , differentially expressed proteins were identified in a human renal proximal tubule cell lineage (HK-2) exposed to human MSC (hMSC) after an ischemic insult. In silico analysis showed that hMSC stimulated antiapoptotic activity, normal ROS handling, energy production, cytoskeleton organization, protein synthesis, and cell proliferation. The proteomic data were validated by parallel experiments demonstrating reduced apoptosis in HK-2 cells and recovery of intracellular ATP levels. qRT-PCR for proteins implicated in the above processes revealed that hMSC exerted their effects by stimulating translation, not transcription. Western blotting of proteins associated with ROS and energy metabolism confirmed their higher abundance in HK-2 cells exposed to hMSC.
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Affiliation(s)
- Milene R da Costa
- Carlos Chagas Filho Institute of Biophysics, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil; National Institute of Science and Technology for Structural Biology and Bioimaging, Rio de Janeiro, Brazil
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Kang JH, Toita R, Kim CW, Katayama Y. Protein kinase C (PKC) isozyme-specific substrates and their design. Biotechnol Adv 2012; 30:1662-72. [DOI: 10.1016/j.biotechadv.2012.07.004] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2012] [Revised: 07/17/2012] [Accepted: 07/18/2012] [Indexed: 11/30/2022]
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Gill J, Ahluwalia MK, Geller D, Gorlick R. New targets and approaches in osteosarcoma. Pharmacol Ther 2012; 137:89-99. [PMID: 22983152 DOI: 10.1016/j.pharmthera.2012.09.003] [Citation(s) in RCA: 205] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2012] [Accepted: 08/29/2012] [Indexed: 02/07/2023]
Abstract
Osteosarcoma is the most common primary tumor of bone. Approximately 2/3 of patients who present with localized osteosarcoma can be expected to be cured of their disease with surgery and routine chemotherapy. Only 1/3 of patients with metastases detectable at presentation will be cured. These survival trends have stagnated over the past 20 years using conventional chemotherapy. New agents need to be rationally investigated to strive for improvement in the survival of patients diagnosed with osteosarcoma. This manuscript will review the rationale for conventional chemotherapy used in the treatment of osteosarcoma, as well as agents in varying stages of development that may have promise for treatment in the future.
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Affiliation(s)
- Jonathan Gill
- Department of Pediatrics, Montefiore Medical Center and The Children's Hospital at Montefiore, Bronx, NY, United States
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Kikuchi K, Soundararajan A, Zarzabal LA, Weems CR, Nelon LD, Hampton ST, Michalek JE, Rubin BP, Fields AP, Keller C. Protein kinase C iota as a therapeutic target in alveolar rhabdomyosarcoma. Oncogene 2012; 32:286-95. [PMID: 22349825 PMCID: PMC3360112 DOI: 10.1038/onc.2012.46] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Alveolar rhabdomyosarcoma is an aggressive pediatric cancer exhibiting skeletal muscle differentiation. New therapeutic targets are required to improve the dismal prognosis for invasive or metastatic alveolar rhabdomyosarcoma. Protein kinase C iota (PKCι) has been shown to play an important role in tumorigenesis of many cancers but little is known about its role in rhabdomyosarcoma. Our gene expression studies in human tumor samples revealed overexpression of PRKCI. We confirmed overexpression of PKCι at the mRNA and protein level using our conditional mouse model that authentically recapitulates the progression of rhabdomyosarcoma in humans. Inhibition of Prkci by RNA interference resulted in a dramatic decrease in anchorage-independent colony formation. Interestingly, treatment of primary cell cultures using aurothiomalate (ATM), which is a gold-containing classical anti-rheumatic agent and a PKCι-specific inhibitor, resulted in decreased interaction between PKCι and Par6, decreased Rac1 activity and reduced cell viability at clinically relevant concentrations. Moreover, co-treatment with ATM and vincristine, a microtubule inhibitor currently used in rhabdomyosarcoma treatment regimens, resulted in a combination index (C. I.) of 0.470–0.793 through cooperative accumulation of non-proliferative multinuclear cells in the G2/M phase, indicating that these two drugs synergize. For in vivo tumor growth inhibition studies, ATM demonstrated a trend towards enhanced vincristine sensitivity. Overall, these results suggest that PKCι is functionally important in alveolar rhabdomyosarcoma anchorage-independent growth and tumor cell proliferation and that combination therapy with ATM and microtubule inhibitors holds promise for the treatment of alveolar rhabdomyosarcoma.
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Affiliation(s)
- K Kikuchi
- Pediatric Cancer Biology Program, Papé Family Pediatric Research Institute, Department of Pediatrics, Oregon Health & Science University, Portland, OR 97239-3098, USA
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Sancho V, Berna MJ, Thill M, Jensen RT. PKCθ activation in pancreatic acinar cells by gastrointestinal hormones/neurotransmitters and growth factors is needed for stimulation of numerous important cellular signaling cascades. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2011; 1813:2145-56. [PMID: 21810446 DOI: 10.1016/j.bbamcr.2011.07.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2011] [Revised: 07/12/2011] [Accepted: 07/13/2011] [Indexed: 02/08/2023]
Abstract
The novel PKCθ isoform is highly expressed in T-cells, brain and skeletal muscle and originally thought to have a restricted distribution. It has been extensively studied in T-cells and shown to be important for apoptosis, T-cell activation and proliferation. Recent studies showed its presence in other tissues and importance in insulin signaling, lung surfactant secretion, intestinal barrier permeability, platelet and mast-cell functions. However, little information is available for PKCθ activation by gastrointestinal (GI) hormones/neurotransmitters and growth factors. In the present study we used rat pancreatic acinar cells to explore their ability to activate PKCθ and the possible interactions with important cellular mediators of their actions. Particular attention was paid to cholecystokinin (CCK), a physiological regulator of pancreatic function and important in pathological processes affecting acinar function, like pancreatitis. PKCθ-protein/mRNA was present in the pancreatic acini, and T538-PKCθ phosphorylation/activation was stimulated only by hormones/neurotransmitters activating phospholipase C. PKCθ was activated in time- and dose-related manner by CCK, mediated 30% by high-affinity CCK(A)-receptor activation. CCK stimulated PKCθ translocation from cytosol to membrane. PKCθ inhibition (by pseudostrate-inhibitor or dominant negative) inhibited CCK- and TPA-stimulation of PKD, Src, RafC, PYK2, p125(FAK) and IKKα/β, but not basal/stimulated enzyme secretion. Also CCK- and TPA-induced PKCθ activation produced an increment in PKCθ's direct association with AKT, RafA, RafC and Lyn. These results show for the first time the PKCθ presence in pancreatic acinar cells, its activation by some GI hormones/neurotransmitters and involvement in important cell signaling pathways mediating physiological responses (enzyme secretion, proliferation, apoptosis, cytokine expression, and pathological responses like pancreatitis and cancer growth).
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Affiliation(s)
- Veronica Sancho
- Digestive Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-1804, USA
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Low expression of PP2A regulatory subunit B55α is associated with T308 phosphorylation of AKT and shorter complete remission duration in acute myeloid leukemia patients. Leukemia 2011; 25:1711-7. [PMID: 21660042 PMCID: PMC3191228 DOI: 10.1038/leu.2011.146] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The regulation of Protein Kinase B (AKT) is a dynamic process that depends on the balance between phosphorylation by upstream kinases for activation and inactivation by dephosphorylation by protein phosphatases. Phosphorylated AKT is commonly found in acute myeloid leukemia (AML) and confers an unfavorable prognosis. Understanding the relative importance of upstream kinases and AKT phosphatase in the activation of AKT is relevant for the therapeutic targeting of this signaling axis in AML. The B55α subunit of Protein Phosphatase 2A (PP2A) has been implicated in AKT dephosphorylation but its role in regulating AKT in AML is unknown. We examined B55α protein expression in blast cells derived from 511 AML patients using Reverse Phase Protein Analysis (RPPA). B55α protein expression was lower in AML cells compared to normal CD34+ cells. B55α protein levels negatively correlated with T308 phosphorylation levels. Low levels of B55α were associated with shorter complete remission duration demonstrating that decreased expression is an adverse prognostic factor in AML. These findings suggest that decreased B55α expression in AML is at least partially responsible for increased AKT signaling in AML and suggests that therapeutic targeting of PP2A could counteract this.
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The Ras-ERK and PI3K-mTOR pathways: cross-talk and compensation. Trends Biochem Sci 2011; 36:320-8. [PMID: 21531565 DOI: 10.1016/j.tibs.2011.03.006] [Citation(s) in RCA: 1270] [Impact Index Per Article: 97.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2011] [Revised: 03/21/2011] [Accepted: 03/25/2011] [Indexed: 12/18/2022]
Abstract
The Ras-extracellular signal-regulated kinase (Ras-ERK) and phosphatidylinositol 3-kinase-mammalian target of rapamycin (PI3K-mTOR) signaling pathways are the chief mechanisms for controlling cell survival, differentiation, proliferation, metabolism, and motility in response to extracellular cues. Components of these pathways were among the first to be discovered when scientists began cloning proto-oncogenes and purifying cellular kinase activities in the 1980s. Ras-ERK and PI3K-mTOR were originally modeled as linear signaling conduits activated by different stimuli, yet even early experiments hinted that they might intersect to regulate each other and co-regulate downstream functions. The extent of this cross-talk and its significance in cancer therapeutics are now becoming clear.
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