Dataset Information

Icotinib hydrochloride enhances chemo- and radiosensitivity by inhibiting EGFR signaling and attenuating RAD51 expression and function in Hela S3 cells.

ABSTRACT: Background:Radiotherapy and cisplatin-based chemotherapy are currently considered as standard treatments employed for advanced cervical cancer (CC). However, patients with local recurrence or distant metastasis continue to have poor outcomes. EGFR overexpression correlated with chemo/radioresistance, and disease failure has been well proved in the previous studies. Hence, the aim of this study was to explore the therapeutic efficacy and underlying mechanism of the sensitization to radiation or cisplatin of icotinib hydrochloride (IH), a high-selective EGFR tyrosine kinase inhibitor (TKI), in the Hela S3 human CC cell line. Methods:Cell proliferation was measured with cell counting kit-8 (CCK-8) assay. Flow cytometry analysis was performed to examine cell cycle distribution and apoptosis. The phosphorylation of EGFR and its downstream signaling molecules were measured by Western blot analysis. ?-H2AX foci and RAD51 foci in the cellular nucleus were visualized using immunofluoresence staining. Expression levels of RAD51 in the whole cells and subceullar fractions were detected to demonstrate the impact of IH on DNA repair. Results:IH can significantly inhibit cell proliferation, redistribute cell cycle, enhance apoptosis and impair DNA damage response of Hela S3 cells following radiation or cisplatin treatment through suppressing the activation of the EGFR signaling pathway and attenuating the expression and function of homologous recombination (HR) protein RAD51. Conclusion:This study suggests that IH is a potential sensitizer in radiotherapy and cisplatin-based chemotherapy for CC and RAD51 may serve as a prognosis biomarker for this combination treatment.

SUBMITTER: Wang X

PROVIDER: S-EPMC5843137 | biostudies-literature | 2018

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Icotinib hydrochloride enhances chemo- and radiosensitivity by inhibiting EGFR signaling and attenuating RAD51 expression and function in Hela S3 cells.

Wang Xuanxuan X Gu Yanjun Y Liu Hai H Shi Liming L Sun Xiaonan X

OncoTargets and therapy 20180305

<h4>Background</h4>Radiotherapy and cisplatin-based chemotherapy are currently considered as standard treatments employed for advanced cervical cancer (CC). However, patients with local recurrence or distant metastasis continue to have poor outcomes. EGFR overexpression correlated with chemo/radioresistance, and disease failure has been well proved in the previous studies. Hence, the aim of this study was to explore the therapeutic efficacy and underlying mechanism of the sensitization to radiat ...[more]

PMID: 29551903

Similar Datasets

Project description:BackgroundRadiosensitivity is limited in cervical cancer (CC) patients due to acquired radiation resistance. In our previous studies, we found that immediate-early response 5 (IER5) is upregulated in CC cells upon radiation exposure and decreases cell survival by promoting apoptosis. The details on the transcriptional regulation of radiation-induced IER5 expression are unknown. Studies in recent years have suggested that Pol II-associated factor 1 (PAF1) is a pivotal transcription factor for certain genes "induced" during tumor progression. In this study, we investigated the role of PAF1 in regulating IER5 expression during CC radiotherapy.MethodsPAF1 expression in CC cells was measured by western blotting, immunohistochemistry, and qRT-PCR, and the localization of PAF1 and IER5 was determined by immunofluorescence. The effect of PAF1 and IER5 knockdown by siRNA in Siha and Hela cells was studied by western blotting, qRT-PCR, CCK-8 assay, and flow cytometry. The physical interaction of PAF1 with the IER5 promoter and enhancers was confirmed using chromatin immunoprecipitation and qPCR with or without enhancers knockout by CRISPR/Cas9.ResultsWe confirmed that PAF1 was highly expressed in CC cells and that relatively low expression of IER5 was observed in cells with highly expressed PAF1 in the nucleus. PAF1 knockdown in Siha and Hela cells was associated with increased expression of IER5, reduced cell viability and higher apoptosis rate in response to radiation exposure, while simultaneous PAF1 and IER5 knockdown had little effect on the proportion of apoptotic cells. We also found that PAF1 hindered the transcription of IER5 by promoting Pol II pausing at the promoter-proximal region, which was primarily due to the binding of PAF1 at the enhancers.ConclusionsPAF1 reduces CC radiosensitivity by inhibiting IER5 transcription, at least in part by regulating its enhancers. PAF1 might be a potential therapeutic target for overcoming radiation resistance in CC patients.

Dataset Information

Icotinib hydrochloride enhances chemo- and radiosensitivity by inhibiting EGFR signaling and attenuating RAD51 expression and function in Hela S3 cells.

Publications

Icotinib hydrochloride enhances chemo- and radiosensitivity by inhibiting EGFR signaling and attenuating RAD51 expression and function in Hela S3 cells.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets