Overexpression of HMGA1 confers radioresistance by transactivating RAD51 in cholangiocarcinoma
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ABSTRACT:
SUBMITTER: Song J
PROVIDER: S-EPMC8556338 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:HMGA1 protein is an architectural transcription factor that has been implicated in the progression of multiple malignant tumors. However, the role of HMGA1 in the growth and metastasis of gastric cancer (GC) has not yet been elucidated. Here, we show that HMGA1 is overexpressed in GC cells and the high expression of HMGA1 was correlated with worse survival in GC patients using a bioinformatics assay. Functionally, HMGA1 affected the EdU incorporation, colony formation, migration and invasion of GC cells by exogenously increasing or decreasing the expression of HMGA1. Mechanistically, HMGA1 directly bound to the SUZ12 and CCDC43 promoter and transactivated its expression in GC cells. Inhibition of SUZ12 and CCDC43 attenuated the proliferation, migration and invasiveness of HMGA1-overexpressing GC cells in vitro. Moreover, both HMGA1 and SUZ12/CCDC43 were highly expressed in cancer cells but not in normal gastric tissues, and their expressions were positively correlated. Finally, a tail vein metastatic assay showed that HMGA1 promoted SUZ12/CCDC43-mediated GC cell metastasis in vivo. Our findings suggest that HMGA1 promotes GC growth and metastasis by transactivating SUZ12 and CCDC43 expression, highlighting HMGA1 as a potential prognostic biomarker in the treatment of GC.
| S-EPMC8266323 | biostudies-literature
Project description:Glioblastoma (GBM) is the most common type of primary tumor in central nervous system in adult with a 5-year survival rate of ≤5%. Despite of recent advances in tumor radiotherapy, the prognosis of GBM remains to be dismal due to radioresistance. In this study, we identified CD81 as a potential biomarker of GBM radioresistance with the analysis of upregulated genes in human glioma radioresistant cell lines U251R and T98G in comparison with U251 cells. In vitro and in vivo experiments demonstrated that suppressing CD81 by siRNA/shRNA enhanced radiation-induced cell killing and DNA damage of γ-H2AX formation, and delayed tumor xenograft growth of GBM. Mechanistically, we found that knockdown of CD81 significantly decreased radiation-induced expression of nuclear Rad51, a key protein involved in homologous recombination repair (HRR) of DNA, suggesting that CD81 is essential for DNA damage response. Meanwhile, when the cells were treated with B02, a Rad51 inhibitor, silencing CD81 would not sensitize GBM cells to radiation, which further illustrates that Rad51 acts as an effector protein of CD81 in tumor radioresistance. Dual immunofluorescence staining of CD81 and Rad51 illustrated that nuclear membrane CD81 contributed to the nuclear transport of Rad51 after irradiation. In conclusion, we demonstrated for the first time that CD81 not only played a vital role in DNA repair through regulating Rad51 nuclear transport, but also might serve as a potential target of GBM radiotherapy.
| S-EPMC8122253 | biostudies-literature
Project description:Myeloid cell leukemia sequence 1 (Mcl-1), an antiapoptotic member of the Bcl-2 family, is often overexpressed in tumor cells limiting the therapeutic success. Mcl-1 differs from other Bcl-2 members by its high turnover rate. Its expression level is tightly regulated by ubiquitylating and deubiquitylating enzymes. Interaction of Mcl-1 with certain Bcl-2 homology domain 3 (BH3)-only members of the Bcl-2 family can limit the access to Mcl-1 ubiquitin ligase E3 and stabilizes the antiapoptotic protein. In addition, the overexpression of the deubiquitinase ubiquitin-specific protease 9x (USP9x) can result in the accumulation of Mcl-1 by removing poly-ubiquitin chains from Mcl-1 preventing its proteasomal degradation. Analyzing radiation-induced apoptosis in Jurkat cells, we found that Mcl-1 was downregulated more efficiently in sensitive parental cells than in a resistant subclone. The decline of Mcl-1 correlated with cell death induction and clonogenic survival. Knockdown of BH3-only proteins Bim, Puma, and Noxa did not affect Mcl-1 level or radiation-induced apoptosis. However, ionizing radiation resulted in activation of USP9x and enhanced deubiquitination of Mcl-1 in the radioresistant cells preventing fast Mcl-1 degradation. USP9x knockdown enhanced radiation-induced decrease of Mcl-1 and sensitized the radioresistant cells to apoptosis induction, whereas USP9x knockdown alone did not change Mcl-1 level in unirradiated cells. Together, our results indicate that radiation-induced activation of USP9x inhibits Mcl-1 degradation and apoptosis resulting in increased radioresistance.
| S-EPMC3479835 | biostudies-other
Project description:Malignant gliomas represent one group of tumors that poorly respond to ionizing radiation (IR) alone or combined with chemotherapeutic agents because of the intrinsic or acquired resistance. In this study, TIP-1 was identified as one novel protein that confers resistance of glioma cells to IR.Meta-analysis indicated that high TIP-1 expression levels correlate with the poor prognosis of human malignant gliomas after radiotherapy. Studies with established human glioma cell lines demonstrated that TIP-1 depletion with specific shRNAs sensitized the cells to IR, whereas an ectopic expression of TIP-1 protected the glioma cells from the IR-induced DNA damage and cell death. Biochemical studies indicated that TIP-1 protein promoted p53 ubiquitination and resulted in a reduced p53 protein level. Furthermore, p53 and its ubiquitination are required for the TIP-1 regulated cellular response to IR. A yeast two-hybrid screening identified that TIP-1, through its single PDZ domain, binds to the carboxyl terminus of LZAP that has been studied as one tumor suppressor functioning through ARF binding and p53 activation. It was revealed that the presence of TIP-1 enhances the protein association between LZAP and ARF and modulates the functionality of ARF/HDM2 toward multi-ubiquitination of p53, while depleting TIP-1 rescued p53 from polyubiquitination and degradation in the irradiated glioma cells. Studies with a mouse xenograft model indicated that depleting TIP-1 within D54 cells improved the tumor growth control with IR.This study provided the first evidence showing that TIP-1 modulates p53 protein stability and is involved in the radioresistance of malignant gliomas, suggesting that antagonizing TIP-1 might be one novel approach to sensitize malignant gliomas to radiotherapy.
| S-EPMC3444456 | biostudies-other
Project description:Glioblastoma multiforme (GBM) continues to be the most frequently diagnosed and lethal primary brain tumor. Adjuvant chemo-radiotherapy remains the standard of care following surgical resection. In this study, using reverse phase protein arrays (RPPAs), we assessed the biological effects of radiation on signaling pathways to identify potential radiosensitizing molecular targets. We identified subsets of proteins with clearly concordant/discordant behavior between irradiated and non-irradiated GBM cells in vitro and in vivo. Moreover, we observed high expression of Forkhead box protein M1 (FOXM1) in irradiated GBM cells both in vitro and in vivo. Recent evidence of FOXM1 as a master regulator of metastasis and its important role in maintaining neural, progenitor, and GBM stem cells, intrigued us to validate it as a radiosensitizing target. Here we show that FOXM1 inhibition radiosensitizes GBM cells by abrogating genes associated with cell cycle progression and DNA repair, suggesting its role in cellular response to radiation. Further, we demonstrate that radiation induced stimulation of FOXM1 expression is dependent on STAT3 activation. Co-immunoprecipitation and co-localization assays revealed physical interaction of FOXM1 with phosphorylated STAT3 under radiation treatment. In conclusion, we hypothesize that FOXM1 regulates radioresistance via STAT3 in GBM cells. We also, show GBM patients with high FOXM1 expression have poor prognosis. Collectively our observations might open novel opportunities for targeting FOXM1 for effective GBM therapy.
| S-EPMC5340228 | biostudies-literature
Project description:Radiotherapy has been widely used for the clinical management of esophageal squamous cell carcinoma. However, radioresistance remains a serious concern that prevents the efficacy of esophageal squamous cell carcinoma (ESCC) radiotherapy. REV7, the structural subunit of eukaryotic DNA polymerase ζ, has multiple functions in bypassing DNA damage and modulating mitotic arrest in human cell lines. However, the expression and molecular function of REV7 in ESCC progression remains unclear. In this study, we first examined the expression of REV7 in clinical ESCC samples, and we found higher expression of REV7 in ESCC tissues compared to matched adjacent or normal tissues. Knockdown of REV7 resulted in decreased colony formation and increased apoptosis in irradiated Eca-109 and TE-1 cells coupled with decreased tumor weight in a xenograft nude mouse model postirradiation. Conversely, overexpression of REV7 resulted in radioresistance in vitro and in vivo. Moreover, silencing of REV7 induced increased reactive oxygen species levels postirradiation. Proteomic analysis of REV7-interacting proteins revealed that REV7 interacted with peroxiredoxin 2 (PRDX2), a well-known antioxidant protein. Existence of REV7-PRDX2 complex and its augmentation postirradiation were further validated by immunoprecipitation and immunofluorescence assays. REV7 knockdown significantly disrupted the presence of nuclear PRDX2 postirradiation, which resulted in oxidative stress. REV7-PRDX2 complex also assembled onto DNA double-strand breaks, whereas REV7 knockdown evidently increased double-strand breaks that were unmerged by PRDX2. Taken together, the present study sheds light on REV7-modulated radiosensitivity through interacting with PRDX2, which provides a novel target for ESCC radiotherapy.
| S-EPMC6398896 | biostudies-other
Project description:Background: Metastasis is the major reason for the high mortality of colorectal cancer (CRC). However, the molecular mechanism underlying CRC metastasis remains unclear. Here, we report a novel role of homeobox B5 (HOXB5), a member of the HOX family, in promoting CRC metastasis. Method: The expression of HOXB5 and its target genes were examined by immunohistochemistry in human CRC. Chromatin immunoprecipitation and luciferase reporter assays were performed to measure the transcriptional regulation of target genes by HOXB5. The metastatic capacities of CRC cells were evaluated by in vivo lung and liver metastatic models. Results: The elevated expression of HOXB5 was positively correlated with distant metastasis, higher AJCC stage, and poor prognosis in CRC patients. HOXB5 expression was an independent and significant risk factor for the recurrence and survival in CRC patients. Overexpression of HOXB5 promoted CRC metastasis by transactivating metastatic related genes, C-X-C motif chemokine receptor 4 (CXCR4) and integrin subunit beta 3 (ITGB3). C-X-C motif chemokine ligand 12 (CXCL12), which is the ligand of CXCR4, upregulated HOXB5 expression through the extracellular regulated protein kinase (ERK)/ETS proto-oncogene 1, transcription factor (ETS1) pathway. The knockdown of HOXB5 decreased CXCL12-enhanced CRC metastasis. Furthermore, AMD3100, a specific CXCR4 inhibitor, significantly suppressed HOXB5-mediated CRC metastasis. HOXB5 expression was positively correlated with CXCR4 and ITGB3 expression in human CRC tissues, and patients with positive co-expression of HOXB5/CXCR4, or HOXB5/ITGB3 exhibited the worst prognosis. Conclusion: Our study implicates HOXB5 as a prognostic biomarker in CRC, and defines a CXCL12-HOXB5-CXCR4 positive feedback loop that plays an important role in promoting CRC metastasis.
| S-EPMC7806482 | biostudies-literature
Project description:Outcome for children with high-risk neuroblastoma (NB) remains suboptimal. Recurrence and metastasis caused by chemo-resistance is an underlying mechanism contributing to the poor prognosis. Aberrant expression of Rad51 is implicated in both radio- and chemo-sensitivity in many human malignancies. However, its clinical significance and relationship with chemo-sensitivity in NB remain undefined. In this study, Rad51 expression was first evaluated in 70 surgically resected NB specimens by immunochemistry using tissue microarray and the correlation with clinic-pathologic features including survival was assessed. We then conducted microarray-based search with the Tumor Neuroblastoma public datasets to validate the immunochemistry results. Furthermore, the role of Rad51 in drug sensitivity was studied by using short hairpin RNA in the human NB SK-N-BE(2) and SH-SY5Y cells with treatment of doxorubicin. Our findings demonstrated for the first time that Rad51 is a prognostic marker in NB and down-regulation of Rad51 can lead to chemo-sensitizing effect in human NB cells.
| S-EPMC6789219 | biostudies-literature
Project description:Cholangiocarcinoma (CHOL) is a malignancy arising from either the intrahepatic or the extrahepatic bile ducts which carries a severe prognosis. HMGA1 is a transcription factor which has a high expression level in many types of cancer. In this study, we find HMGA1 overexpression in CHOL. In order to investigate the regulatory mechanism of HMGA1 in CHOL, we performed RNA-seq in HUCCT1 cells with HMGA1 knock down compared with control in three repeat.
2021-11-03 | GSE163759 | GEO
Project description:A long noncoding RNA (lncRNA), nuclear enriched abundant transcript 1 (NEAT1) variant 1 (NEAT1v1), is involved in the maintenance of cancer stem cells (CSCs) in hepatocellular carcinoma (HCC). CSCs are suggested to play important roles in therapeutic resistance. Therefore, we investigated whether NEAT1v1 is involved in the sensitivity to radiation therapy in HCC. Gene knockdown was performed using short hairpin RNAs, and NEAT1v1-overexpressing HCC cell lines were generated by stable transfection with a NEAT1v1-expressing plasmid DNA. Cells were irradiated using an X-ray generator. We found that NEAT1 knockdown enhanced the radiosensitivity of HCC cell lines and concomitantly inhibited autophagy. NEAT1v1 overexpression enhanced autophagy in the irradiated cells and conferred radioresistance. Gamma-aminobutyric acid receptor-associated protein (GABARAP) expression was downregulated by NEAT1 knockdown, whereas it was upregulated in NEAT1v1-overexpressing cells. Moreover, GABARAP was required for NEAT1v1-induced autophagy and radioresistance as its knockdown significantly inhibited autophagy and sensitized the cells to radiation. Since GABARAP is a crucial protein for the autophagosome-lysosome fusion, our results suggest that NEAT1v1 confers radioresistance to HCC by promoting autophagy through GABARAP.
| S-EPMC8775719 | biostudies-literature