Epigenetic Interventions Increase the Radiation Sensitivity of Cancer Cells

Title:Epigenetic Interventions Increase the Radiation Sensitivity of Cancer Cells

Volume: 20 Issue: 11

Author(s): Juan Ren, Yongli Chu, Hongbing Ma, Yuelang Zhang, Xiaozhi Zhang, Dongli Zhao, Zongfang Li, Jiansheng Wang, Yan-e Gao, Lisha Xiao, Rui Liu, Jiansheng Qian, Yan Liu, Hongxia Wei and Shiwen Jiang

Affiliation:

Keywords: Demethylating agents, histone deacetylase inhibitors, anticancer drugs, radiotherapy, radiosensitization, epigenetic.

Abstract: Epigenetic changes including DNA methylation, histone modifications, chromatin remodeling and microRNAs play critical roles in tumorigenesis and tumor development. Reversal of epigenetic changes sensitizes some tumor cells to radiation.

DNMT-I enhances the response of tumor cells to radiotherapy. AZA demethylated promoters of genes related to ionizing radiation response, such as p16 and hMLH1. The genes expression of the p53, RASSF1, and DAPK gene families was increased by 5-aza-CdR, which induces G2-M phase arrest and increased apoptosis.

HDAC-I has both anti-tumor activity and radiation sensitization activity. HDAC-I disrupts both DNA damage sensing and repair processes: HDAC-I disrupts the association between HDAC enzyme and DNA sensor proteins 53BP1 and ATM. HDAC-I changes the acetylation status of both proteins involved in homologous recombination (HR) repair pathway which include BRCA1, Rad51, and Rad50, and proteins involved in non-homologous end joining (NHEJ) repair pathway which include Ku70, and DNA-PK. HDACs are also implicated as essential components in the DNA repair process itself. Besides the radiosensitizing mechanism of intervention of DNA repair, other possible mechanisms including cell cycle redistribution, acetylation of Hsp90, increased apoptosis, and decreased survival signals are also suggested.

Some miRNAs also regulate the radiosensitivity of tumor cells. Inhibition of miR-34 expression or function, downregulation of miR-155, upregulation of miR-18a, Overexpression let-7g or knocking down LIN28B, and ectopically overexpressed miR-10 in cells with low endogenous miR-101 level increase the response of cells to irradiation. For radiation-resistant cancer cells, miR-7 sensitizes the radiation for cells which activated EGFR-PI3K-AKT signaling pathway;

Cite this article as:

Ren Juan, Chu Yongli, Ma Hongbing, Zhang Yuelang, Zhang Xiaozhi, Zhao Dongli, Li Zongfang, Wang Jiansheng, Gao Yan-e, Xiao Lisha, Liu Rui, Qian Jiansheng, Liu Yan, Wei Hongxia and Jiang Shiwen, Epigenetic Interventions Increase the Radiation Sensitivity of Cancer Cells, Current Pharmaceutical Design 2014; 20 (11) . https://dx.doi.org/10.2174/13816128113199990529

DOI https://dx.doi.org/10.2174/13816128113199990529	Print ISSN 1381-6128
Publisher Name Bentham Science Publisher	Online ISSN 1873-4286