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Kulka LAM, Fangmann PV, Panfilova D, Olzscha H. Impact of HDAC Inhibitors on Protein Quality Control Systems: Consequences for Precision Medicine in Malignant Disease. Front Cell Dev Biol 2020; 8:425. [PMID: 32582706 PMCID: PMC7291789 DOI: 10.3389/fcell.2020.00425] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2020] [Accepted: 05/07/2020] [Indexed: 12/21/2022] Open
Abstract
Lysine acetylation is one of the major posttranslational modifications (PTM) in human cells and thus needs to be tightly regulated by the writers of this process, the histone acetyl transferases (HAT), and the erasers, the histone deacetylases (HDAC). Acetylation plays a crucial role in cell signaling, cell cycle control and in epigenetic regulation of gene expression. Bromodomain (BRD)-containing proteins are readers of the acetylation mark, enabling them to transduce the modification signal. HDAC inhibitors (HDACi) have been proven to be efficient in hematologic malignancies with four of them being approved by the FDA. However, the mechanisms by which HDACi exert their cytotoxicity are only partly resolved. It is likely that HDACi alter the acetylation pattern of cytoplasmic proteins, contributing to their anti-cancer potential. Recently, it has been demonstrated that various protein quality control (PQC) systems are involved in recognizing the altered acetylation pattern upon HDACi treatment. In particular, molecular chaperones, the ubiquitin proteasome system (UPS) and autophagy are able to sense the structurally changed proteins, providing additional targets. Recent clinical studies of novel HDACi have proven that proteins of the UPS may serve as biomarkers for stratifying patient groups under HDACi regimes. In addition, members of the PQC systems have been shown to modify the epigenetic readout of HDACi treated cells and alter proteostasis in the nucleus, thus contributing to changing gene expression profiles. Bromodomain (BRD)-containing proteins seem to play a potent role in transducing the signaling process initiating apoptosis, and many clinical trials are under way to test BRD inhibitors. Finally, it has been demonstrated that HDACi treatment leads to protein misfolding and aggregation, which may explain the effect of panobinostat, the latest FDA approved HDACi, in combination with the proteasome inhibitor bortezomib in multiple myeloma. Therefore, proteins of these PQC systems provide valuable targets for precision medicine in cancer. In this review, we give an overview of the impact of HDACi treatment on PQC systems and their implications for malignant disease. We exemplify the development of novel HDACi and how affected proteins belonging to PQC can be used to determine molecular signatures and utilized in precision medicine.
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Affiliation(s)
- Linda Anna Michelle Kulka
- Medical Faculty, Institute of Physiological Chemistry, Martin-Luther-University Halle-Wittenberg, Halle (Saale), Germany
| | - Pia-Victoria Fangmann
- Medical Faculty, Institute of Physiological Chemistry, Martin-Luther-University Halle-Wittenberg, Halle (Saale), Germany
| | - Diana Panfilova
- Medical Faculty, Institute of Physiological Chemistry, Martin-Luther-University Halle-Wittenberg, Halle (Saale), Germany
| | - Heidi Olzscha
- Medical Faculty, Institute of Physiological Chemistry, Martin-Luther-University Halle-Wittenberg, Halle (Saale), Germany
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2
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Jafari A, Rezaei-Tavirani M, Farhadihosseinabadi B, Taranejoo S, Zali H. HSP90 and Co-chaperones: Impact on Tumor Progression and Prospects for Molecular-Targeted Cancer Therapy. Cancer Invest 2020; 38:310-328. [PMID: 32274949 DOI: 10.1080/07357907.2020.1752227] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Heat shock protein 90 (HSP90), a highly and unique chaperone, presents as a double-edged sword. It plays an essential role in many physiological and pathological processes, including tumor development. The current review highlights a recent understanding of the roles of HSP90 in molecular mechanisms underlying cancer survival and progression. HSP90 and its client proteins through the regulation of oncoproteins including signaling proteins, receptors, and transcriptional factors involved in tumorigenesis. It also has potential clinical application as diagnostic and prognostic biomarkers for assessing cancer progression. In this way, using HSP90 to develop new anticancer therapeutic agents including HSP90 inhibitors, anti-HSP90 antibody, and HSP90-based vaccines has been promising.
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Affiliation(s)
- Ameneh Jafari
- Student Research Committee, Shahid Beheshti University of Medical Sciences, Tehran, Iran.,Proteomics Research Center, School of Allied Medical Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Mostafa Rezaei-Tavirani
- Proteomics Research Center, School of Allied Medical Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | | | - Shahrouz Taranejoo
- Wellman Centre for Photomedicine, Harvard-MIT Division of Health Sciences and Technology (HST), Boston, MA, USA
| | - Hakimeh Zali
- Department of Tissue engineering and applied cell, School of Advanced Technologies in Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
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Functional redundancy of HSPA1, HSPA2 and other HSPA proteins in non-small cell lung carcinoma (NSCLC); an implication for NSCLC treatment. Sci Rep 2019; 9:14394. [PMID: 31591429 PMCID: PMC6779912 DOI: 10.1038/s41598-019-50840-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Accepted: 09/12/2019] [Indexed: 12/14/2022] Open
Abstract
Heat shock proteins (HSPs) are a large group of chaperones considered critical for maintaining cellular proteostasis. Their aberrant expression in tumors can modulate the course of processes defined as hallmarks of cancer. Previously, we showed that both stress-inducible HSPA1 and testis-enriched HSPA2, highly homologous members of the HSPA (HSP70) family, are often overexpressed in non-small cell lung carcinoma (NSCLC). HSPA1 is among the best characterized cancer-related chaperones, while the significance of HSPA2 for cancer remains poorly understood. Previously we found that in primary NSCLC, HSPA1 was associated with good prognosis while HSPA2 correlated with bad prognosis, suggesting possible different roles of these proteins in cancer. Therefore, in this work we investigated the impact of HSPA1 and HSPA2 on NSCLC cell phenotype. We found that neither paralog-selective nor simultaneous knockdown of HSPA1 and HSPA2 gene expression reduced growth and chemoresistance of NSCLC cells. Only blocking of HSPA proteins using pan-HSPA inhibitors, VER-155008 or JG-98, exerted potent anticancer effect on NSCLC cells, albeit the final outcome was cell type-dependent. Pan-HSPA inhibition sensitized NSCLC cells to bortezomib, but not to platinum derivates. Our result suggests the inhibitors of proteasome and HSPAs seem an effective drug combination for pre-clinical development in highly aggressive NSCLC.
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Intrinsic proteotoxic stress levels vary and act as a predictive marker for sensitivity of cancer cells to Hsp90 inhibition. PLoS One 2018; 13:e0202758. [PMID: 30138434 PMCID: PMC6107219 DOI: 10.1371/journal.pone.0202758] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Accepted: 08/08/2018] [Indexed: 12/16/2022] Open
Abstract
Response of tumours to Hsp90 inhibitors is highly variable and their clinical effects are unpredictable, emphasising the need for a predictive marker. We postulated that sensitivity to Hsp90 inhibitors is connected to basal proteotoxic stress that makes cells dependent on Hsp90. Therefore, we assessed HSF1 as a general sensor of proteotoxic stress and correlated its activity with sensitivity to three separate small molecule Hsp90 inhibitors in seven breast cancer cell lines representing each of the different cancer subtypes. Flow cytometry was used to analyse the viability of breast cancer cell lines after Hsp90 inhibition. HSF1 activity was characterised by Ser326 phosphorylation and the transactivation capacity of HSF1 was determined by qPCR analysis of the ratios of HSF1-dependent (HOP, Hsp70) and HSF1-independent (CHIP) chaperones and cochaperone mRNAs. We show that the sensitivity of breast cancer cell lines to Hsp90 inhibition is highly variable. The basal levels of phosphorylated HSF1 also vary between cell lines and the magnitude of change in HSF1 phosphorylation after Hsp90 inhibition showed a negative correlation with sensitivity to Hsp90 inhibitors. Similarly, the basal transactivation capacity of HSF1, determined by the ratio of Hsp70 or HOP mRNA to CHIP mRNA level, is directly proportional to sensitivity to Hsp90 inhibitors. Increasing basal HSF1 activity by prior heat shock sensitised cells to Hsp90 inhibition. These results demonstrate that endogenous HSF1 activity varies between individual cancer cell lines and inversely reflects their sensitivity to Hsp90 inhibitors, suggesting that basal proteotoxic stress is an important and generalised predictor of response. Mechanistically, the data indicate that high endogenous proteotoxic stress levels sensitise to Hsp90 inhibition due to the inability to respond adequately to further proteotoxic stress. HSF1 activity therefore represents a potential biomarker for therapy with Hsp90 inhibitors, which may be useful for the rational design of future clinical studies.
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5
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Park S, Park JA, Yoo H, Park HB, Lee Y. Proteasome inhibitor-induced cleavage of HSP90 is mediated by ROS generation and caspase 10-activation in human leukemic cells. Redox Biol 2017; 13:470-476. [PMID: 28715732 PMCID: PMC5512190 DOI: 10.1016/j.redox.2017.07.010] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2017] [Revised: 07/07/2017] [Accepted: 07/11/2017] [Indexed: 12/26/2022] Open
Abstract
Heat shock protein 90 (HSP90) is a molecular chaperone that supports the stability of client proteins. The proteasome is one of the targets for cancer therapy, and studies are underway to use proteasome inhibitors as anti-cancer drugs. In this study, we found that HSP90 was cleaved to a 55 kDa protein after treatment with proteasome inhibitors including MG132 in leukemia cells but was not cleaved in other tissue-derived cells. HSP90 has two major isoforms (HSP90α and HSP90β), and both were cleaved by MG132 treatment. MG132 treatment also induced a decrease in HSP90 client proteins. MG132 treatment generated ROS, and the cleavage of HSP90 was blocked by a ROS scavenger, N-acetylcysteine (NAC). MG132 activated several caspases, and the activation was reduced by pretreatment with NAC. Based on an inhibitor study, the cleavage of HSP90 induced by MG132 was dependent on caspase 10 activation. Furthermore, active recombinant caspase 10 induced HSP90 cleavage in vitro. MG132 upregulated VDUP-1 expression and reduced the GSH levels implying that the regulation of redox-related proteins is involved. Taken all together, our results suggest that the cleavage of HSP90 by MG132 treatment is mediated by ROS generation and caspase 10 activation. HSP90 cleavage may provide an additional mechanism involved in the anti-cancer effects of proteasome inhibitors. Proteasome inhibitors induce cleavage of HSP90. MG132 induces ROS generation via VDUP-1 upregulation and GSH downregulation. ROS-mediated active caspase 10 cleaves HSP90.
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Affiliation(s)
- Sangkyu Park
- Department of Biochemistry, College of Natural Sciences, Chungbuk National University, Cheongju, Chungbuk 28644, Republic of Korea
| | - Jeong-A Park
- Department of Biochemistry, College of Natural Sciences, Chungbuk National University, Cheongju, Chungbuk 28644, Republic of Korea
| | - Hwanmin Yoo
- Department of Biochemistry, College of Natural Sciences, Chungbuk National University, Cheongju, Chungbuk 28644, Republic of Korea
| | - Han-Bum Park
- Department of Biochemistry, College of Natural Sciences, Chungbuk National University, Cheongju, Chungbuk 28644, Republic of Korea
| | - Younghee Lee
- Department of Biochemistry, College of Natural Sciences, Chungbuk National University, Cheongju, Chungbuk 28644, Republic of Korea.
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A molecular hypothesis to explain direct and inverse co-morbidities between Alzheimer's Disease, Glioblastoma and Lung cancer. Sci Rep 2017; 7:4474. [PMID: 28667284 PMCID: PMC5493619 DOI: 10.1038/s41598-017-04400-6] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Accepted: 05/25/2017] [Indexed: 11/27/2022] Open
Abstract
Epidemiological studies indicate that patients suffering from Alzheimer’s disease have a lower risk of developing lung cancer, and suggest a higher risk of developing glioblastoma. Here we explore the molecular scenarios that might underlie direct and inverse co-morbidities between these diseases. Transcriptomic meta-analyses reveal significant numbers of genes with inverse patterns of expression in Alzheimer’s disease and lung cancer, and with similar patterns of expression in Alzheimer’s disease and glioblastoma. These observations support the existence of molecular substrates that could at least partially account for these direct and inverse co-morbidity relationships. A functional analysis of the sets of deregulated genes points to the immune system, up-regulated in both Alzheimer’s disease and glioblastoma, as a potential link between these two diseases. Mitochondrial metabolism is regulated oppositely in Alzheimer’s disease and lung cancer, indicating that it may be involved in the inverse co-morbidity between these diseases. Finally, oxidative phosphorylation is a good candidate to play a dual role by decreasing or increasing the risk of lung cancer and glioblastoma in Alzheimer’s disease.
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Graner AN, Hellwinkel JE, Lencioni AM, Madsen HJ, Harland TA, Marchando P, Nguyen GJ, Wang M, Russell LM, Bemis LT, Anchordoquy TJ, Graner MW. HSP90 inhibitors in the context of heat shock and the unfolded protein response: effects on a primary canine pulmonary adenocarcinoma cell line. Int J Hyperthermia 2016; 33:303-317. [PMID: 27829290 DOI: 10.1080/02656736.2016.1256503] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND Agents targeting HSP90 and GRP94 are seldom tested in stressed contexts such as heat shock (HS) or the unfolded protein response (UPR). Tumor stress often activates HSPs and the UPR as pro-survival mechanisms. This begs the question of stress effects on chemotherapeutic efficacy, particularly with drugs targeting chaperones such as HSP90 or GRP94. We tested the utility of several HSP90 inhibitors, including PU-H71 (targeting GRP94), on a primary canine lung cancer line under HS/UPR stress compared to control conditions. METHODS We cultured canine bronchoalveolar adenocarcinoma cells that showed high endogenous HSP90 and GRP94 expression; these levels substantially increased upon HS or UPR induction. We treated cells with HSP90 inhibitors 17-DMAG, 17-AAG or PU-H71 under standard conditions, HS or UPR. Cell viability/survival was assayed. Antibody arrays measured intracellular signalling and apoptosis profiles. RESULTS HS and UPR had varying effects on cells treated with different HSP90 inhibitors; in particular, HS and UPR promoted resistance to inhibitors in short-term assays, but combinations of UPR stress and PU-H571 showed potent cytotoxic activity in longer-term assays. Array data indicated altered signalling pathways, with apoptotic and pro-survival implications. UPR induction + dual targeting of HSP90 and GRP94 swayed the balance toward apoptosis. CONCLUSION Cellular stresses, endemic to tumors, or interventionally inducible, can deflect or enhance chemo-efficacy, particularly with chaperone-targeting drugs. Stress is likely not held accountable when testing new pharmacologics or assessing currently-used drugs. A better understanding of stress impacts on drug activities should be critical in improving therapeutic targeting and in discerning mechanisms of drug resistance.
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Affiliation(s)
- Arin N Graner
- a Department of Neurosurgery , University of Colorado Denver , Aurora , CO , USA
| | - Justin E Hellwinkel
- a Department of Neurosurgery , University of Colorado Denver , Aurora , CO , USA.,b School of Medicine , University of Colorado School of Medicine , Aurora , CO , USA
| | - Alex M Lencioni
- a Department of Neurosurgery , University of Colorado Denver , Aurora , CO , USA.,c University of Arkansas for Medical Sciences , Little Rock , AR , USA
| | - Helen J Madsen
- a Department of Neurosurgery , University of Colorado Denver , Aurora , CO , USA.,b School of Medicine , University of Colorado School of Medicine , Aurora , CO , USA
| | - Tessa A Harland
- a Department of Neurosurgery , University of Colorado Denver , Aurora , CO , USA.,b School of Medicine , University of Colorado School of Medicine , Aurora , CO , USA
| | - Paul Marchando
- d Department of Chemical and Biological Engineering , University of Colorado Boulder , Boulder , CO , USA
| | - Ger J Nguyen
- a Department of Neurosurgery , University of Colorado Denver , Aurora , CO , USA
| | - Mary Wang
- a Department of Neurosurgery , University of Colorado Denver , Aurora , CO , USA
| | - Laura M Russell
- a Department of Neurosurgery , University of Colorado Denver , Aurora , CO , USA
| | - Lynne T Bemis
- e Department of Biomedical Sciences , University of Minnesota , Duluth , MN , USA
| | - Thomas J Anchordoquy
- f Skaggs School of Pharmacy and Pharmaceutical Sciences , University of Colorado Denver , Aurora , CO , USA
| | - Michael W Graner
- a Department of Neurosurgery , University of Colorado Denver , Aurora , CO , USA
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8
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Attar-Schneider O, Drucker L, Gottfried M. Migration and epithelial-to-mesenchymal transition of lung cancer can be targeted via translation initiation factors eIF4E and eIF4GI. J Transl Med 2016; 96:1004-15. [PMID: 27501049 DOI: 10.1038/labinvest.2016.77] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Revised: 05/18/2016] [Accepted: 06/20/2016] [Indexed: 02/06/2023] Open
Abstract
Metastasis underlies cancer morbidity and accounts for disease progression and significant death rates generally and in non-small cell lung cancer (NSCLC) particularly. Therefore, it is critically important to understand the molecular events that regulate metastasis. Accumulating data portray a central role for protein synthesis, particularly translation initiation (TI) factors eIF4E and eIF4G in tumorigenesis and patients' survival. We have published that eIF4E/eIF4GI activities and consequently NSCLC cell migration are modulated by bone-marrow mesenchymal stem cell secretomes, suggesting a role for TI in metastasis. Here, we aimed to expand our understanding of the TI factors significance to NSCLC characteristics, particularly epithelial-to-mesenchymal transition (EMT) and migration, supportive of metastasis. In a model of NSCLC cell lines (H1299, H460), we inhibited eIF4E/eIF4GI's expressions (siRNA, ribavirin) and assessed NSCLC cell lines' migration (scratch), differentiation (EMT, immunoblotting), and expression of select microRNAs (qPCR). Initially, we determined an overexpression of several TI factors (eIF4E, eIF4GI, eIF4B, and DHX29) and their respective targets in NSCLC compared with normal lung samples (70-350%↑, P<0.05). Knockdown (KD) of eIF4E/eIF4GI in NSCLC cell lines (70%↓, P<0.05) also manifested in decreased target levels (ERα, SMAD5, NFkB, CyclinD1, c-MYC, and HIF1α) (20-50%↓, P<0.05). eIF4E/eIF4GI KD also attenuated cell migration (60-75%↓, P<0.05), EMT promoters (15-90%↓, P<0.05), and enhanced EMT suppressors (30-380%↑, P<0.05). The importance of eIF4E KD to NSCLC phenotype was further corroborated with its inhibitor, ribavirin. Changes in expression of essential microRNAs implicated in NSCLC cell migration concluded the study (20-100%, P<0.05). In summary, targeting eIF4E/eIF4GI reduces migration and EMT, both essential for metastasis, thereby underscoring the potential of TI targeting in NSCLC therapy, especially the already clinically employed agents (ribavirin/4EGI). Comparison of these findings with previously reported effects of eIF4E/eIF4GI KD in multiple myeloma suggests a collective role for these TI factors in cancer progression.
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Affiliation(s)
- Oshrat Attar-Schneider
- Lung Cancer Research Laboratory, Lung Cancer Unit, Meir Medical Center, Kfar Saba, Israel.,Oncogenetic Laboratory, Meir Medical Center, Kfar Saba, Israel.,Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Liat Drucker
- Oncogenetic Laboratory, Meir Medical Center, Kfar Saba, Israel.,Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Maya Gottfried
- Lung Cancer Research Laboratory, Lung Cancer Unit, Meir Medical Center, Kfar Saba, Israel.,Oncology Department, Lung Cancer Unit, Meir Medical Center, Kfar Saba, Israel.,Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
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Secretome of human bone marrow mesenchymal stem cells: an emerging player in lung cancer progression and mechanisms of translation initiation. Tumour Biol 2015; 37:4755-65. [PMID: 26515338 DOI: 10.1007/s13277-015-4304-3] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2015] [Accepted: 10/20/2015] [Indexed: 12/25/2022] Open
Abstract
Non-small cell lung cancer (NSCLC) remains the most common cause of cancer-related death worldwide. Patients presenting with advanced-stage NSCLC have poor prognosis, while metastatic spread accounts for >70 % of patient's deaths. The major advances in the treatment of lung cancer have brought only minor improvements in survival; therefore, novel strategic treatment approaches are urgently needed. Accumulating data allocate a central role for the cancer microenvironment including mesenchymal stem cells (MSCs) in acquisition of drug resistance and disease relapse. Furthermore, studies indicate that translation initiation factors are over expressed in NSCLC and negatively impact its prognosis. Importantly, translation initiation is highly modulated by microenvironmental cues. Therefore, we decided to examine the effect of bone marrow MSCs (BM-MSCs) from normal donors on NSCLC cell lines with special emphasis on translation initiation mechanism in the crosstalk. We cultured NSCLC cell lines with BM-MSC conditioned media (i.e., secretome) and showed deleterious effects on the cells' proliferation, viability, death, and migration. We also demonstrated reduced levels of translation initiation factors implicated in cancer progression [eukaryotic translation initiation factor 4E (eIF4E) and eukaryotic translation initiation factor 4GI (eIF4GI)], their targets, and regulators. Finally, we outlined a mechanism by which BM-MSCs' secretome affected NSCLC's mitogen-activated protein kinase (MAPK) signaling pathway, downregulated the cell migration, and diminished translation initiation factors' levels. Taken together, our study demonstrates that there is direct dialogue between the BM-MSCs' secretome and NSCLC cells that manipulates translation initiation and critically affects cell fate. We suggest that therapeutic approach that will sabotage this dialogue, especially in the BM microenvironment, may diminish lung cancer metastatic spread and morbidity and improve the patient's life quality.
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Solárová Z, Mojžiš J, Solár P. Hsp90 inhibitor as a sensitizer of cancer cells to different therapies (review). Int J Oncol 2014; 46:907-26. [PMID: 25501619 DOI: 10.3892/ijo.2014.2791] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2014] [Accepted: 10/22/2014] [Indexed: 11/06/2022] Open
Abstract
Hsp90 is a molecular chaperone that maintains the structural and functional integrity of various client proteins involved in signaling and many other functions of cancer cells. The natural inhibitors, ansamycins influence the Hsp90 chaperone function by preventing its binding to client proteins and resulting in their proteasomal degradation. N- and C-terminal inhibitors of Hsp90 and their analogues are widely tested as potential anticancer agents in vitro, in vivo as well as in clinical trials. It seems that Hsp90 competitive inhibitors target different tumor types at nanomolar concentrations and might have therapeutic benefit. On the contrary, some Hsp90 inhibitors increased toxicity and resistance of cancer cells induced by heat shock response, and through the interaction of survival signals, that occured as side effects of treatments, could be very effectively limited via combination of therapies. The aim of our review was to collect the data from experimental and clinical trials where Hsp90 inhibitor was combined with other therapies in order to prevent resistance as well as to potentiate the cytotoxic and/or antiproliferative effects.
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Affiliation(s)
- Zuzana Solárová
- Department of Pharmacology, Faculty of Medicine, P.J. Šafárik University, 040 01 Košice, Slovak Republic
| | - Ján Mojžiš
- Department of Pharmacology, Faculty of Medicine, P.J. Šafárik University, 040 01 Košice, Slovak Republic
| | - Peter Solár
- Laboratory of Cell Biology, Institute of Biology and Ecology, Faculty of Science, P.J. Šafárik University, 040 01 Košice, Slovak Republic
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