scholarly journals Antitumor Effect of Lenvatinib Combined with Alisertib in Hepatocellular Carcinoma by Targeting the DNA Damage Pathway

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Jianwen Hao ◽  
Qizhen Peng ◽  
Keruo Wang ◽  
Ge Yu ◽  
Yi Pan ◽  
...  
Keyword(s):  
Hepatocellular Carcinoma ◽  
Dna Damage ◽  
Anticancer Agents ◽  
Immunohistochemical Staining ◽  
Antitumor Effect ◽  
Combined Treatment ◽  
Single Agent ◽  
Xenograft Model ◽  
Cell Counting ◽  
Inhibition Of Proliferation

Background and Aim. Although a strong antitumor effect of lenvatinib has been noted for patients with unresectable hepatocellular carcinoma (HCC), its efficacy requires improvement. It is imperative to seek therapeutic strategies that combine Lenvatinib with other anticancer agents. In this study, we investigated the anticancer effect of combining lenvatinib with alisertib, aurora A kinase (AURKA) target drug, against HCC in vitro and in vivo. Methods. Immunohistochemical staining, sequencing, and genetic analysis of liver cancer tissues were performed. The antitumor efficacy of single-agent or combination treatment was measured by cell counting kit-8 assay and colony formation assays. Their antiproliferative and apoptosis activity is evaluated by cell cycle analyses and wound healing assays. The DNA-related proteins were also measured by Western blotting and immunohistochemical staining. The HepG2 xenograft model was used to detect the effects of lenvatinib-alisertib on the antitumor activity. Results. AURKA was found to be upregulated in HCC tissues (77.3%, 17/22). Combined alisertib and lenvatinib treatment significantly enhanced the inhibition of proliferation and migration in HepG2 and Hep3B cell lines compared to single-agent treatments (all P s < 0.01 ). Alisertib alone or in combination with lenvatinib demonstrated a significant increase in the percentage of super-G2 cells (lenvatinib 1 μM vs. lenvatinib 1 μM + alisertib 0.1 μM 8.84 ± 0.84 vs. 34.0 ± 1.54 , P < 0.001 ). Discontinuous spindles and missegregated chromosomes in HCC cells treated with alisertib in combination with lenvatinib were observed. We further revealed that combined treatment inhibited the expression of DNA damage pathway proteins compared to those of single-agent treatments. In nude mice, combined administration of alisertib combined with lenvatinib significantly enhanced the suppression of tumor growth and induced apoptosis (all P s < 0.01 ). Conclusions. Our findings provide evidence for the possible use of alisertib in combination with lenvatinib in the treatment of HCC for better therapeutic outcomes.

scholarly journals Silencing VEGF enhances the radiosensitivity of the radioresistant human nasopharyngeal carcinoma cell line CNE-2R by inhibiting autophagy through the activation of mTOR pathway

2020 ◽  
Author(s):  
Li Chen ◽  
Guoxiang Lin ◽  
Kaihua Chen ◽  
Fangzhu Wan ◽  
Yongchu Sun ◽  
...  
Keyword(s):  
Dna Damage ◽  
Nasopharyngeal Carcinoma ◽  
Cell Line ◽  
Western Blotting ◽  
Xenograft Model ◽  
Mtor Pathway ◽  
Angiogenic Factor ◽  
Cell Counting

Abstract Background: Vascular endothelial growth factor (VEGF) is an important pro-angiogenic factor. VEGF was reported to promote the occurrence of autophagy, which enhanced to the radioresistance of tumors. The purpose of our study was to investigate the influence of VEGF silencing on the radiosensitivity of nasopharyngeal carcinoma radioresistant cell line CNE-2R and the underlying mechanisms.Methods: The radiosensitivity of CNE-2R cells after silencing VEGF was detected by cell counting kit 8 (CCK-8) and clonogenic assay, cell cycle and apoptosis was subjected to flow cytometry. DNA damage and autophagy were observed by immunofluorescence and western blotting. The interaction between VEGF and mTOR was confirmed by western blotting and co-immunoprecipitation analysis. In vivo, the effect of VEGF on radiosensitivity of NPC cells was investigated through xenograft model, furthermore, immunohistochemistry and TUNEL assay were used to further verify the relationship between autophagy and radiosensitivity in NPC after VEGF depletion.Results: Downregulation of VEGF significantly inhibited cell proliferation and induced apoptosis of CNE-2R cells after radiotherapy in vitro and in vivo. In addition, VEGF knockdown not only decreased autophagy level, but also delayed the DNA damage repair in CNE-2R cells after irradiation. Mechanistically, silencing VEGF suppressed autophagy through the activation of mTOR pathway.Conclusion: VEGF depletion increased radiosensitivity of NPC radioresistant cell CNE-2R by suppressing autophagy via the activation of mTOR pathway.

Azacitidine/Decitabine Synergism with the NEDD8-Activating Enzyme Inhibitor MLN4924 in Pre-Clinical AML Models

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 578-578 ◽  
Author(s):  
Peter G Smith ◽  
Tary Traore ◽  
Steve Grossman ◽  
Usha Narayanan ◽  
Jennifer S Carew ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Dna Damage ◽  
Cell Death ◽  
Synthetic Lethality ◽  
Single Agent ◽  
Xenograft Model ◽  
S Phase ◽  
Myelogenous Leukemia ◽  
Phase Accumulation

Abstract Abstract 578 MLN4924 is an investigational small molecule inhibitor of NEDD8-activating enzyme that has shown clinical activity in a Phase I clinical trial in Acute Myelogenous Leukemia (AML). To identify potential combination partners of MLN4924 we performed a high-throughput viability screen in AML cells with 40 approved and investigational agents. In vitro characterization of AML cell lines revealed two distinct cell cycle phenotypes suggesting alternate mechanism of action following MLN4924 inhibition of NAE. One group demonstrated moderate S-phase accumulation with greater than 4N DNA content consistent with DNA-rereplication as a result of CDT1 dysregulation. The second group demonstrated distinct and rapid accumulation of subG1 cells without S-phase accumulation or DNA re-replication suggesting induction of apoptosis and cell death. These observations led us to choose two cells lines representative of each mechanism to understand potential for synergy in AML cells. Two hypomethylating agents were included in the screen (decitabine and azacitidine) and were found to be synergistic with MLN4924 by Combination Index and Blending Synergy Analysis. These data were confirmed with a second NAE inhibitor that is structurally dissimilar to MLN4924. The combination of azacitidine and MLN4924 were shown to result in significantly increased DNA-damage and cell death compared to single agent alone as measured by Western Blotting and FACS analysis of cell cycle distributions. In vivo studies were performed in HL-60 and THP-1 xenografts using MLN4924 on a clinically relevant dosing schedule twice weekly. Single agent azacitidine at its Maximum Tolerated Dose (MTD) had minimal activity in the HL-60 model and was combined with a sub-optimal dose of MLN4924 that when combined induced complete and sustained tumor regressions. The mechanism for the apparent synthetic lethality in this in vivo model is currently under evaluation; however it is supported by a dramatic elevation in DNA damage and cleaved caspase-3 in vivo in the combination arm. A second xenograft model (THP-1) that was also insensitive to single agent azacitidine treatment underwent complete and sustained tumor regressions when combined with MLN4924. Thus MLN4924 and azacitidine can combine to produce synergistic antitumor activity in pre-clinical models of AML. Coupled with their non-overlapping clinical toxicities these data suggest the potential for future combination studies in clinical trials. Disclosures: Smith: Millennium Pharmaceuticals: Employment. Traore:Millennium Pharmaceuticals: Employment. Grossman:Millennium Pharmaceuticals: Employment. Narayanan:Millennium Pharmaceuticals: Employment. Carew:Millennium Pharmaceuticals: Research Funding. Lublinksky:Millennium Pharmaceuticals: Employment. Kuranda:Millennium Pharmaceuticals: Employment. Milhollen:Millennium Pharmaceuticals: Employment.

scholarly journals Upregulation of ERK-EGR1-heparanase axis by HDAC inhibitors provides targets for rational therapeutic intervention in synovial sarcoma

2021 ◽  
Vol 40 (1) ◽  
Author(s):  
Cinzia Lanzi ◽  
Enrica Favini ◽  
Laura Dal Bo ◽  
Monica Tortoreto ◽  
Noemi Arrighetti ◽  
...  
Keyword(s):  
Synovial Sarcoma ◽  
Cell Response ◽  
Histone Deacetylases ◽  
Molecular Mechanisms ◽  
Combined Treatment ◽  
Single Agent ◽  
Hdac Inhibitors ◽  
Xenograft Model

Abstract Background Synovial sarcoma (SS) is an aggressive soft tissue tumor with limited therapeutic options in advanced stage. SS18-SSX fusion oncogenes, which are the hallmarks of SS, cause epigenetic rewiring involving histone deacetylases (HDACs). Promising preclinical studies supporting HDAC targeting for SS treatment were not reflected in clinical trials with HDAC inhibitor (HDACi) monotherapies. We investigated pathways implicated in SS cell response to HDACi to identify vulnerabilities exploitable in combination treatments and improve the therapeutic efficacy of HDACi-based regimens. Methods Antiproliferative and proapoptotic effects of the HDACi SAHA and FK228 were examined in SS cell lines in parallel with biochemical and molecular analyses to bring out cytoprotective pathways. Treatments combining HDACi with drugs targeting HDACi-activated prosurvival pathways were tested in functional assays in vitro and in a SS orthotopic xenograft model. Molecular mechanisms underlying synergisms were investigated in SS cells through pharmacological and gene silencing approaches and validated by qRT-PCR and Western blotting. Results SS cell response to HDACi was consistently characterized by activation of a cytoprotective and auto-sustaining axis involving ERKs, EGR1, and the β-endoglycosidase heparanase, a well recognized pleiotropic player in tumorigenesis and disease progression. HDAC inhibition was shown to upregulate heparanase by inducing expression of the positive regulator EGR1 and by hampering negative regulation by p53 through its acetylation. Interception of HDACi-induced ERK-EGR1-heparanase pathway by cell co-treatment with a MEK inhibitor (trametinib) or a heparanase inhibitor (SST0001/roneparstat) enhanced antiproliferative and pro-apoptotic effects. HDAC and heparanase inhibitors had opposite effects on histone acetylation and nuclear heparanase levels. The combination of SAHA with SST0001 prevented the upregulation of ERK-EGR1-heparanase induced by the HDACi and promoted caspase-dependent cell death. In vivo, the combined treatment with SAHA and SST0001 potentiated the antitumor efficacy against the CME-1 orthotopic SS model as compared to single agent administration. Conclusions The present study provides preclinical rationale and mechanistic insights into drug combinatory strategies based on the use of ERK pathway and heparanase inhibitors to improve the efficacy of HDACi-based antitumor therapies in SS. The involvement of classes of agents already clinically available, or under clinical evaluation, indicates the transferability potential of the proposed approaches.

scholarly journals FBXL6 governs c-MYC to promote hepatocellular carcinoma through ubiquitination and stabilization of HSP90AA1

2020 ◽  
Author(s):  
Weidong Shi ◽  
Lanyun Feng ◽  
Shu Dong ◽  
Zhouyu Ning ◽  
Yongqiang Hua ◽  
...  
Keyword(s):  
Hepatocellular Carcinoma ◽  
Liver Cancer ◽  
Mrna Expression ◽  
Biological Effects ◽  
Xenograft Model ◽  
Cell Counting ◽  
Luciferase Reporter ◽  
Liver Cancers ◽  
F Box Protein

Abstract BACKGROUND: Heat shot protein 90 (HSP90) AA1 functions as an onco-protein to regulate the assembly, manipulation, folding and degradation of its client proteins, including c-MYC. However, the mechanisms underlying the regulation of HSP90AA1 are poorly understood.METHODS: Transcriptome RNA-sequencing data of Liver hepatocellular carcinoma (LIHC) samples were used to detect the mRNA expression of FBXL6. Immunoprecipitation/Mass Spectrum (IP/MS) method was used to identify the interacting proteins of FBXL6. The co-immunoprecipitation assay was used to determine the interaction between FBXL6 and HSP90AA1. The in vivo ubiquitination assay was performed to determine the regulation of HSP90AA1 by FBXL6. Luciferase reporter and chromatin immunoprecipitation assays were used to determine the transcriptional regulation of FBXL6 by c-MYC. Cell counting and colony formation assays were implemented to detect the biological effects of FBXL6 on the growth of HCC cells in vitro. The effect of FBXL6 on HCC tumor growth in vivo was studied in a tumor xenograft model in mice. RESULTS: Here, we identified the orphan F-box protein FBXL6, a substrate recognition subunit of an SCF (Skp1-Cul1-F-box protein) complex, as the ubiquitin ligase for HSP90AA1. FBXL6 promoted K63-dependent ubiquitination of HSP90AA1 to stabilize it. Through analysis of TCGA dataset, we found that FBXL6 was significantly increased in liver cancer tissues and positively correlated with c-MYC pathway. FBXL6 accumulation in liver cancers causes the stabilization and activation of c-MYC by preventing HSP90AA1 degradation. Activated c-MYC, which in turn directly bound to the promoter region of FBXL6 to induce its mRNA expression.CONCLUSION: Collectively, our data revealed an unknown FBXL6-HSP90AA1-c-MYC axis which might contribute to the oncogenesis of liver cancer, and we propose that inhibition of FBXL6 might represent an effective therapeutic strategy for liver cancer treatment.

scholarly journals FBXL6 governs c-MYC to promote hepatocellular carcinoma through ubiquitination and stabilization of HSP90AA1

2020 ◽  
Author(s):  
Weidong Shi ◽  
Lanyun Feng ◽  
Shu Dong ◽  
Zhouyu Ning ◽  
Yongqiang Hua ◽  
...  
Keyword(s):  
Hepatocellular Carcinoma ◽  
Liver Cancer ◽  
Mrna Expression ◽  
Biological Effects ◽  
Xenograft Model ◽  
Cell Counting ◽  
Luciferase Reporter ◽  
Liver Cancers ◽  
F Box Protein

Abstract BackgroundHeat shot protein 90 (HSP90) AA1 functions as an onco-protein to regulate the assembly, manipulation, folding and degradation of its client proteins, including c-MYC. However, the mechanisms underlying the regulation of HSP90AA1 are poorly understood.MethodsTranscriptome RNA-sequencing data of Liver hepatocellular carcinoma (LIHC) samples were used to detect the mRNA expression of FBXL6. Immunoprecipitation/Mass Spectrum (IP/MS) method was used to identify the interacting proteins of FBXL6. The co-immunoprecipitation assay was used to determine the interaction between FBXL6 and HSP90AA1. The in vivo ubiquitination assay was performed to determine the regulation of HSP90AA1 by FBXL6. Luciferase reporter and chromatin immunoprecipitation assays were used to determine the transcriptional regulation of FBXL6 by c-MYC. Cell counting and colony formation assays were implemented to detect the biological effects of FBXL6 on the growth of HCC cells in vitro. The effect of FBXL6 on HCC tumor growth in vivo was studied in a tumor xenograft model in mice. ResultsHere, we identified the orphan F-box protein FBXL6, a substrate recognition subunit of an SCF (Skp1-Cul1-F-box protein) complex, as the ubiquitin ligase for HSP90AA1. FBXL6 promoted K63-dependent ubiquitination of HSP90AA1 to stabilize it. Through analysis of multiple public liver cancer GEO data, we found that FBXL6 was significantly increased in liver cancer tissues and positively correlated with c-MYC pathway. FBXL6 accumulation in liver cancers causes the stabilization and activation of c-MYC by preventing HSP90AA1 degradation. Activated c-MYC, which in turn directly binds to the promoter region of FBXL6 to induce its mRNA expression.ConclusionCollectively, our data revealed an unknown axis of FBXL6-HSP90AA1-c-MYC which might contribute to the oncogenesis of liver cancer, and we propose that inhibition of FBXL6 might represent an effective therapeutic strategy for liver cancer treatment.

scholarly journals Modulation of SIRT3 expression through CDK4/6 enhances the anti-cancer effect of sorafenib in hepatocellular carcinoma cells

2020 ◽  
Author(s):  
HanHee Jo ◽  
Yusun Park ◽  
Taehun Kim ◽  
Jisu Kim ◽  
JongSook Lee ◽  
...  
Keyword(s):  
Hepatocellular Carcinoma ◽  
Cell Lines ◽  
Combined Treatment ◽  
Xenograft Model ◽  
Cancer Tissue ◽  
Sorafenib Treatment ◽  
Tumor Types ◽  
Related Proteins ◽  
Sirt3 Expression ◽  
Hcc Cells

Abstract Background : Hepatocellular carcinoma (HCC) is the leading cause of cancer-related deaths worldwide. The only drug currently approved for clinical use in the treatment of advanced HCC is sorafenib. However, many patients with HCC show reduced sensitivity to sorafenib during treatment. SIRT3, a member of the mammalian sirtuin family, is a tumor suppressor in certain tumor types. However, only few studies have investigated the effects of SIRT3 on tumor prognosis and sorafenib sensitivity in patients with HCC. Here, we aimed to investigate the correlation between SIRT3 expression and glucose metabolism and proliferation in HCC and discover effective compounds that increase endogenous SIRT3 modulation effect of sorafenib. Methods: To determine the correlation between SIRT3 and glucose related proteins, immunostaining was performed with liver cancer tissue using various antibodies. To investigate whether the expression of SIRT3 in HCC is related to the resistance to sorafenib, we treated sorafenib after the modulation of SIRT3 levels in HCC cell lines (overexpression in Huh7, knockdown in HepG2). We also employed PD0332991 to modulate the SIRT3 expression in HCC cell and conducted functional assays. Results: SIRT3 expression was downregulated in high glycolytic and proliferative HCC cells of human patients, xenograft model and HCC cell lines. Moreover, SIRT3 expression was downregulated after sorafenib treatment, resulting in reduced drug sensitivity in HCC cell lines. To enhance the anti-tumor effect of sorafenib, we employed PD0332991 (CDK4/6-Rb inhibitor) based on the correlation between SIRT3 and phosphorylated retinoblastoma protein in HCC. Notably, combined treatment with sorafenib and PD0332991 showed an enhancement of the anti-tumor effect in HCC cells. Conclusions: Our data suggest that the modulation of SIRT3 by CDK4/6 inhibition might be useful for HCC therapy together with sorafenib, which, unfortunately, has limited efficacy and whose use is often associated with drug resistance.

scholarly journals Modulation of SIRT3 expression through CDK4/6 enhances the anti-cancer effect of sorafenib in hepatocellular carcinoma cells

2020 ◽  
Author(s):  
HanHee Jo ◽  
Kyung Sik Kim ◽  
Taehun Kim ◽  
Yusun Park ◽  
Jisu Kim ◽  
...  
Keyword(s):  
Hepatocellular Carcinoma ◽  
Cell Lines ◽  
Combined Treatment ◽  
Xenograft Model ◽  
Cancer Tissue ◽  
Sorafenib Treatment ◽  
Anti Cancer ◽  
Tumor Types ◽  
Related Proteins ◽  
Sirt3 Expression

Abstract Background : : Hepatocellular carcinoma (HCC) is the leading cause of cancer-related deaths worldwide. The only drug currently approved for clinical use in the treatment of advanced HCC is sorafenib. However, many patients with HCC show reduced sensitivity to sorafenib during treatment. SIRT3, a member of the mammalian sirtuin family, is a tumor suppressor in certain tumor types. To date, a few studies have investigated the effects of SIRT3 on tumor prognosis and sorafenib sensitivity in patients with HCC. Thus, this study aimed to investigate the correlation between SIRT3 expression and glucose metabolism and proliferation in HCC and to discover effective compounds that increase endogenous SIRT3 modulation effect of sorafenib. Methods: To determine the correlation between SIRT3 and glucose related proteins, immunostaining was performed with liver cancer tissue using various antibodies. To investigate whether the expression of SIRT3 in HCC is related to the resistance to sorafenib, we treated sorafenib after the modulation of SIRT3 levels in HCC cell lines (overexpression in Huh7, knockdown in HepG2). We also employed PD0332991 to modulate the SIRT3 expression in HCC cell and conducted functional assays. Results: SIRT3 expression is downregulated in high glycolytic and proliferative HCC of human patients, xenograft model and HCC cell lines. We also demonstrated that SIRT3 expression was downregulated after sorafenib treatment, resulting in reduced drug sensitivity in HCC cell lines. To enhance the anti-tumor effect of sorafenib, we employed PD0332991 (CDK4/6-Rb inhibitor) based on the correlation between SIRT3 and phospho-Rb in HCC. In addition, combined treatment with sorafenib and PD0332991 showed a synergic anti-tumor effect in HCC cells. Conclusions: Taken together, our data suggest that the modulation of SIRT3 by CDK4/6 inhibition might be used for HCC therapy together with sorafenib, which, unfortunately, has limited efficacy and whose use is often associated with drug resistance.

scholarly journals Co-inhibition of HDAC and MLL-menin interaction targets MLL-rearranged acute myeloid leukemia cells via disruption of DNA damage checkpoint and DNA repair

2019 ◽  
Vol 11 (1) ◽  
Author(s):  
Jing Ye ◽  
Jie Zha ◽  
Yuanfei Shi ◽  
Yin Li ◽  
Delin Yuan ◽  
...  
Keyword(s):  
Dna Damage ◽  
Dna Repair ◽  
Acute Myeloid Leukemia ◽  
Myeloid Leukemia ◽  
Clinical Investigation ◽  
Combined Treatment ◽  
Single Agent ◽  
Ros Generation ◽  
Dna Damage Checkpoint ◽  
Acute Myeloid

Abstract While the aberrant translocation of the mixed-lineage leukemia (MLL) gene drives pathogenesis of acute myeloid leukemia (AML), it represents an independent predictor for poor prognosis of adult AML patients. Thus, small molecule inhibitors targeting menin-MLL fusion protein interaction have been emerging for the treatment of MLL-rearranged AML. As both inhibitors of histone deacetylase (HDAC) and menin-MLL interaction target the transcription-regulatory machinery involving epigenetic regulation of chromatin remodeling that governs the expression of genes involved in tumorigenesis, we hypothesized that these two classes of agents might interact to kill MLL-rearranged (MLL-r) AML cells. Here, we report that the combination treatment with subtoxic doses of the HDAC inhibitor chidamide and the menin-MLL interaction inhibitor MI-3 displayed a highly synergistic anti-tumor activity against human MLL-r AML cells in vitro and in vivo, but not those without this genetic aberration. Mechanistically, co-exposure to chidamide and MI-3 led to robust apoptosis in MLL-r AML cells, in association with loss of mitochondrial membrane potential and a sharp increase in ROS generation. Combined treatment also disrupted DNA damage checkpoint at the level of CHK1 and CHK2 kinases, rather than their upstream kinases (ATR and ATM), as well as DNA repair likely via homologous recombination (HR), but not non-homologous end joining (NHEJ). Genome-wide RNAseq revealed gene expression alterations involving several potential signaling pathways (e.g., cell cycle, DNA repair, MAPK, NF-κB) that might account for or contribute to the mechanisms of action underlying anti-leukemia activity of chidamide and MI-3 as a single agent and particularly in combination in MLL-r AML. Collectively, these findings provide a preclinical basis for further clinical investigation of this novel targeted strategy combining HDAC and Menin-MLL interaction inhibitors to improve therapeutic outcomes in a subset of patients with poor-prognostic MLL-r leukemia.

scholarly journals VEGF knockdown enhances radiosensitivity of nasopharyngeal carcinoma by inhibiting autophagy through the activation of mTOR pathway

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Li Chen ◽  
Guoxiang Lin ◽  
Kaihua Chen ◽  
Fangzhu Wan ◽  
Renba Liang ◽  
...  
Keyword(s):  
Dna Damage ◽  
Nasopharyngeal Carcinoma ◽  
Western Blotting ◽  
Dna Damage Repair ◽  
Xenograft Model ◽  
Mtor Pathway ◽  
Angiogenic Factor ◽  
Cell Counting ◽  
Damage Repair

Abstract Vascular endothelial growth factor (VEGF) is an important pro-angiogenic factor. VEGF was reported to promote the occurrence of autophagy, which enhanced the radioresistance of tumors. The purpose of this study was to investigate the influence of VEGF silencing on the radiosensitivity of nasopharyngeal carcinoma (NPC) cells and the underlying mechanisms. The radiosensitivity of NPC cells after VEGF silencing was detected by cell counting kit 8 (CCK-8) and clonogenic assay, while cell cycle and apoptosis were detected by flow cytometry. The processes of DNA damage, repair and autophagy were examined by immunofluorescence and western blotting. The interaction between VEGF and mTOR was confirmed by western blotting and co-immunoprecipitation studies. The effect of VEGF on radiosensitivity of NPC cells was investigated in vivo using a xenograft model. Furthermore, immunohistochemistry and TUNEL assays were used to verify the relationship between autophagy and radiosensitivity in NPC after VEGF depletion. Downregulation of VEGF significantly inhibited cell proliferation and induced apoptosis of NPC cells after radiotherapy in vitro and in vivo. In addition, VEGF knockdown not only decreased autophagy level, but also delayed the DNA damage repair in NPC cells after irradiation. Mechanistically, silencing VEGF suppressed autophagy through activation of the mTOR pathway. VEGF depletion increased radiosensitivity of NPC cells by suppressing autophagy via activation of the mTOR pathway.

scholarly journals CMTM6 Promotes Migration, Invasion, and EMT by Interacting with and Stabilizing Vimentin in Hepatocellular Carcinoma Cells

2021 ◽  
Author(s):  
Xiaoting Huang ◽  
Leyang Xiang ◽  
Baiyao Wang ◽  
Jijie Hu ◽  
Chunshan Liu ◽  
...  
Keyword(s):  
Hepatocellular Carcinoma ◽  
Colony Formation ◽  
Transmembrane Domain ◽  
Xenograft Model ◽  
Cell Counting ◽  
Migration And Invasion ◽  
Tissue Samples ◽  
Mesenchymal Transition ◽  
Potential Biomarker ◽  
Mouse Xenograft Model

Abstract BackgroundCKLF like MARVEL transmembrane domain containing 6 (CMTM6) has been associated with the development in many kinds of cancers. However, the roles of CMTM6 in hepatocellular carcinoma (HCC) are largely unknown. Thus, the present study aimed to investigate the function of CMTM6 in HCC.MethodsWe analysed CMTM6 levels and functions using human HCC cell lines, paired HCC and adjacent non-tumorous tissues, and a tissue microarray. CMTM6 expression was silenced using short hairpin RNAs and its was overexpressed from a lentivirus vector. CMTM6 mRNA and protein levels were determined using quantitative real-time reverse transcription PCR and western blotting, respectively. Proliferation, colony formation, migration, and invasion were assessed using a Cell counting kit-8, colony formation, wound-healing, and Matrigel invasion assays, respectively. Immunohistochemistry was used to score the expression of CMTM6 in tissue samples. The localization and binding partners of CMTM6 were investigated using immunofluorescence and coimmunoprecipitation experiments, respectively. A mouse xenograft model was used for in vivo studies.ResultsCompared with that in adjacent, non-cancerous tissue, Here, CMTM6 levels were increased in HCC tissue samples. Silencing of CMTM6 suppressed the proliferation, migration, and invasion of HCC cells. Conversely, CMTM6 overexpression enhanced HCC cell invasion, migration, and proliferation. Mechanistically, CMTM6 physically interacts with and stabilizes vimentin, thus inducing epithelial–mesenchymal transition (EMT), which promotes proliferation, migration and invasion. Importantly, in HCC tissues, CMTM6 expression correlated positively with vimentin levels. Poor prognosis of HCC was associated significantly with higher CMTM6 expression. ConclusionsCMTM6 has an important function in HCC proliferation, migration, and invasion, via its interaction with and stabilization of vimentin. CMTM6 might represent a potential biomarker and therapeutic target to treat HCC.

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