Over expression of miR-100 is responsible for the low expression of ATM in the human glioma cell line: M059J

• Type of Material: Article
• Authors: Wooi Loon Ng, Emory University; Dan Yan, Emory University; Xiangming Zhang, Emory University; Yin-Yuan Mo, Southern Illinois University; Ya Wang, Emory University
• Language: English
• Date: 2010-11-10
• Publisher: Elsevier
• Publication Version: Author Accepted Manuscript (After Peer Review)
• Copyright Statement: © 2010 Elsevier B.V. All rights reserved.
• License: Creative Commons Attribution-NonCommerical-NoDerivs 3.0 Unported
• Final Published Version (URL): http://dx.doi.org/10.1016/j.dnarep.2010.08.007
• Title of Journal or Parent Work: DNA Repair
• ISSN: 1568-7864
• Volume: 9
• Issue: 11
• Start Page: 1170
• End Page: 1175
• Grant/Funding Information: This work was supported by NIH grant GM80771 and Emory University School of Medicine start-up funds designated for Y.W.
• Keywords: ATM; ionizing radiation; M059J; miR-100; DNA damage
• Research Categories: Biology, Genetics; Health Sciences, Oncology

Abstract

M059J and M059K cells were isolated from different portions of the same human malignant glioma. M059J cells are more radiosensitive than M059K cells due to the absence of DNA-PKcs and low-expression of ATM. The mechanism concerning the absence of DNA-PKcs in M059J is due to the frameshift mutation in PRKDC (DNA-PKcs gene); however, the reason for the low expression of ATM in M059J cells remains unclear. We showed here that the main reason for the lower ATM level in M059J cells was not related to the transcriptional regulation or protein degradation but was related to post-transcriptional regulation. Based on database information, we found that the 3’-untranslational region (UTR) of ATM contains a miR-100-binding site. By using an RNase protection assay and qRT-PCR, we identified that miR-100 is highly-expressed in M059J cells. We further demonstrated that miR-100 bound to the 3’-UTR of ATM. Knocking-down miR-100 promotes ATM expression in M059J cells. Up-regulating miR-100 in M059K cells and other cancer cells reduces ATM expression and sensitizes these cells to ionizing radiation. These results indicate that ATM is a target of miR-100, elucidating that the low-expression of ATM in M059J cells is mainly due to the high-expression of miR-100. These results also suggest that miR-100 could be a useful tool to target ATM and sensitize tumor cells to ionizing radiation.