Gamma Radiation Induces Apoptosis by Over Expression of PERP Effector of p53-dependent Cell Death in HeLa Cells.

Walid Khalilia,Gül Özcan

doi:10.3390/iecc2021-09222

Abstract

Ionized radiation leads to a modulation of the expression of many genes. Identification of specific genes may allow the determination of pathways important in radiation responses. It was found that PERP induces apoptosis when it is overexpressed. However, the mechanism by which PERP induces apoptosis is still unknown. The objectives of this study were to determine the configuration of several genes in response to gamma radiation treatment. Novel treatment strategy to increase the cancer cell sensitivity to radiotherapy by modulation of the PERP expression could be developed for cervical cancers. Cervical cancer cells were incubated for several periods after were exposed to various doses of gamma radiation, MTT assay were used to explore propagation of HeLa cells, apoptotic Index (AI) were measured using fluorescent microscopy by estimating apoptotic morphological features. While, signalling pathway analyses were performed on up-regulated genes which evaluated using microarray technology. From the results of this study, the proliferation of HeLa cervical cancer cells exposed to gamma radiation was inhibited proportionally with dose and time after exposure. Also, apoptotic morphological features, such as shrinkage of the cell and formation of apoptotic bodies, was clearly visible under the microscope for irradiated HeLa cells. after 48 h. exposure to different doses of gamma radiation, the dose of 32 Gy was specified as an AI dose. The mRNA levels of pro-apoptotic genes such as, PERP; BAX; CASP9; TRAF3 and other factors detected by microarray after treatment with gamma radiation were up-regulated. Whereas, many anti-apoptosis factors were down-regulated. P53 pathway were significantly reinforced after pathway analysis for up- and dawn- regulated genes. For conclusion, gamma radiation induces apoptosis by over expression of PERP factor and p53-dependent cell death in cervical carcinoma HeLa cells.

Highlights

Gamma Radiation (GR), leads to a variety of cellular damages including nucleic acids and membrane hurt
The results of this study after the treatment of a cervical cancer HeLa cells with 2, 8, 16, 32 and 64 Gy of GR for a duration of 0 and 24 hours indicated that radiation inhibits HeLa cells proliferation and apoptosis was raised by time and GR dose rate
Results showed that radiation inhibits proliferation of HeLa cells proportionally with dose and time after exposure to GR. 32Gy radiation doses induced HeLa cell death by 51% at 24 hours post-irradiation time compared with control group

Summary

Introduction

GR, leads to a variety of cellular damages including nucleic acids and membrane hurt. DNA damage leads to a coordinate network of signal transduction pathways involved in cell cycle arrest, DNA repair and the activation of apoptosis processes. Apoptosis is the major mode of programmed cell death, and is characterized by a series of morphological hallmarks, including cell shrinkage, DNA condensation and fragmentation, followed by the formation of apoptotic bodies [1]. Ionized radiation leads to a modulation of the expression of many genes that control complex regulatory pathways. In replay to GR exposure, several signal transduction pathways, such as ERK1/2, JNK, p38, and ATM and transcription factors, such as AP1, NFκB, GADD153, and p53 are activated. Tumor suppressor p53 gene, which regulates apoptosis under stress conditions like hypoxia, ionized radiation and free radical formation initiate p53-mediated DNA repair and apoptosis.

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