Lymphocytes have demonstrated complex molecular responses to induced stress by ionizing radiation. Many of these reactions are mediated through modifications in gene expressions, including the genes involved in apoptosis. The primary aim of this study was to assess the effects of low doses of ionizing radiation on the apoptotic genes, expression levels. The secondary goal was to estimate the time-effect on the modified gene expression caused by low doses of ionizing radiation. Mononuclear cells in culture were exposed to various dose values ranged from 20 to 100 mGy by gamma rays from a Cobalt-60 source. Samples were taken for gene expression analysis at hours 4, 24, 48, 72, and 168 following to exposure. Expression level of two apoptotic genes; BAX (pro-apoptotic) and Bcl-2 (anti-apoptotic) were examined by relative quantitative real-time polymerase chain reaction (PCR), at different time intervals. Radio-sensitivity of peripheral blood mononucleated cells (PBMCs) was measured by the Bcl-2/BAX ratio (as a predictive marker for radio-sensitivity). The non-parametric two independent samples Mann–Whitney U-test were performed to compare means of gene expression. The results of this study revealed that low doses of gamma radiation can induce early down-regulation of the BAX gene of freshly isolated human PBMCs; however, these changes were restored to near normal levels after 168 hours. In most cases, expression of the Bcl-2 anti-apoptotic gene was up-regulated. Four hours following to exposure to low doses of gamma radiation, apoptotic gene expression is modified, this is manifested as adaptive response. Modification of these gene expressions seems to be a principle pathway in the early radioresistance response. In our study, we found that these changes were temporary and faded completely within a week.
Introduction: Breast cancer is a leading cause of cancer-related deaths
in females[1], and circular RNAs (circRNAs) have emerged as a novel
class of noncoding RNAs that play regulatory roles in angiogenesis and
cancer progression. The study of the expression patterns and functional
roles of circRNAs in breast cancer has become an area of growing
interest. The aim of this study was to investigate the relationship
between hsa-circ-00001724 gene expression and breast cancer. method:
Circular RNAs were extracted from tissue samples and cDNAs were
synthesized, followed by RT-PCR of the glyceraldehyde-3-phosphate
dehydrogenase gene as an internal control to ensure the quality of the
synthesized cDNA samples. Negative controls were used in RT-PCR and
qRT-PCR to exclude contamination with genomic DNA and PCR materials, and
a positive control test was also performed. The most appropriate primer
sequences were selected using OligoAnalyzer software and the NCBI
website, and real-time PCR using SYBR Green was used to examine
expression changes. The CT number was determined from the data obtained,
and the resulting graphs were examined in terms of dimer formation. The
Ct values of normal and tumor samples of the CIRC gene were also
subjected to a parametric Kolmogorov-Smirnov test. Results: Real-time
PCR reaction results revealed that the hsa-circ-00001724 gene had lower
expression in cancer tumor samples than in non-tumor samples.
Conclusion: Based on these results, it is hypothesized that
hsa-circ-00001724 may serve as a potential biomarker for breast cancer
diagnosis and prognosis, and may also be a potential target for
therapeutic purposes.
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