MicroR-545 enhanced radiosensitivity via suppressing Ku70 expression in Lewis lung carcinoma xenograft model

Chen Liao,Yanhu Wang,Yanhu Wang,Wei Xiao,Wei Xiao,Jiu Yang,Jiu Yang,Zhiyuan Liu,Zhiyuan Liu,Nuo Zhu,Nuo Zhu,Mei Hong,Mei Hong

doi:10.1186/s12935-015-0207-z

Chen Liao, Yanhu Wang + Show 11 more

Open Access

https://doi.org/10.1186/s12935-015-0207-z

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Abstract

ObjectiveRadiotherapy is an important therapeutic method for lung cancer. However, in clinical situations, cellular resistance to radiotherapy is a significant component of tumor treatment failure. Thus, clarification in cellular mechanism underlying radiosensitivity of cancer cell is urgently needed. In this study, we established a radiation model of Lewis lung carcinoma in C57BL/6 mice and investigated the possible signaling molecule involved in this process.MethodsC57BL/6 mice were subcutaneously transplanted with Lewis lung carcinoma cells and locally irradiated followed by measurement in tumor volume. Levels of miR-545 and Ku70 mRNA expression were determined by using Quantitative Real-Time PCR. Expression of Ku70 was determined by using western blot assay. Cell viability was analyzed by MTT assay. Cell apoptosis was examined by using TUNEL assay.ResultsIn mice bearing Lewis lung carcinoma tumor, local radiotherapy suppressed tumor growth as well as enhanced expression of miR-545 and downregulated Ku70 level. Inhibition of miR-545 expression reduced radiosensitivity of Lewis tumor. In vitro Lewis lung carcinoma cells experiment, we observed that miR-545 regulated Ku70 expression by targeting Ku70 3′UTR and this process was involved in radiotherapy. This was demonstrated by result of cell proliferation assay in which irradiation reduced apoptosis of cells was mediated by miR-545 inactivation which was reversed by Ku70 silence.ConclusionmiR-545 increased radiosensitivity of Lewis lung carcinoma via inhibiting Ku70 expression.

Highlights

Lung cancer continues to be one of the most prevalent malignancies worldwide and is the leading cause of death in both men and women
In vitro Lewis lung carcinoma cells experiment, we observed that miR-545 regulated Ku70 expression by targeting Ku70 3′UTR and this process was involved in radiotherapy
This was demonstrated by result of cell proliferation assay in which irradiation reduced apoptosis of cells was mediated by miR-545 inactivation which was reversed by Ku70 silence

Summary

Introduction

Lung cancer continues to be one of the most prevalent malignancies worldwide and is the leading cause of death in both men and women. There is around 20 % of new cancer cases worldwide were diagnosed in China each year; more people die from lung cancer than from any other kind of cancer. For conveniently be located, approximately 90 % of patients with lung cancer receive external beam radiation treatment as one component of their treatment. Accumulated evidence pointed out that combination of radiation and radiosensitivity-related. Recent studies have revealed that Ku70 may be a susceptibility factor for radiation-related cancers. Inhibition of Ku70 can increase the radiosensitivity of 786-O cells by enhancing apoptosis [3]. Antisense Ku70 using the antisense nucleic acid strategy increased radiosensitivity of human squamous cell lung carcinoma cell line [4].

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