RESUMO
Objective:To investigate the regulating molecules and acting mechanism of TAB182 in HR pathway.Methods:TAB182 in human breast cancer MCF-7 cells was knocked down by shRNA strategy, the TAB182 knockdown MCF-7 as the TAB182 knockdown group, and the MCF-7 cell using the shRNA negative control as the TAB182 negative control group. RNA sequencing and qRT-PCR were performed to screen and verify the differentially expressed genes of HR pathway related to TAB182 depression. Western blot was used to detect protein expression. Immunofluorescence staining of nuclear RAD51 and BrdU was used to check the 3′ ssDNA formation by the end resection. The cell cycle arrest and apoptosis were measured by flow cytometry. Cloning formation assay was used to evaluate the sensitivity TAB182-knockdown cells to radiation.Results:Both quantitative RNA sequencing and qRT-PCR assays showed that TAB182-knockdown significantly decreased the mRNA expression of RPA2( t=17.97, P<0.05). Compared with the TAB182 negative control group, the protein level of RPA2, the number of RAD51 foci, and the 3′ ssDNA-binding nuclear protein marker BrdU in TAB182-knockdown cells were significantly reduced. At 4, 8, and 12 h after actinomycin D treatment, the attenuation of RPA2 mRNA in the TAB182-knockdown cells was accelerated ( t=5.37, 3.79, 3.69, P<0.05). Compared with the TAB182 negative control group, the radiosensitivity and radiation-induced apoptosis in the TAB182-knockdown group were increased ( t=3.48, 11.05, P<0.05), and at 24 h after irradiation, the cell cycle block time was prolonged ( t=8.40, P<0.01). Conclusions:TAB182 plays a role in maintaining RPA2 mRNA stability, thereby promoting HR repair. TAB182 knockdown cells are highly sensitive to ionizing radiation.
RESUMO
Objective:To identify the differentially expressed snoRNAs in the carcinogenesis of cells induced by α-particles radiation and predict the targeted genes and RNA-co-expression networks.Methods:Full transcriptome expression microarray biochips were employed to screen the differentially expressed snoRNAs between human bronchial epithelial BEP2D cell line and its derivative malignantly transformed cell line BERP35T-4 established by α-particle irradiation. The expression changes of snoRNAs and their derived sdRNAs were confirmed by qRT-PCR. The functional domains, targets and co-expression networks of snoRNA were predicted by bioinformatics analysis.Results:Consistent with the result of microarray assay, the expression changes of the screened snoRNAs were confirmed by qRT-PCR. The expressions of sno116 family decreased in BERP35T-4, which was 0.105% ( t=26.60, P<0.01) of BEP2D, and they were generally down-regulated in radiation-induced carcinogenic BERP35T-4 cells and the human lung cancer cell lines A549 and H1299. It was also found that the expression level of the sdRNAs derived from sno116-14 was significantly different in the same cells. It was speculated that these less expressed sdRNAs of sno116-14 could be due to degradation as the consequence of interaction with their targets. The co-expression networks of sno116 family with other types of RNA were established, and the predicted targets of sno116-14 included ZNF280D, TFDP1, CCDC28B, RPS6KA3, CANX, RUNX1 and KALRN, which were related to the functions of cell proliferation and cytoskeletal structure. Conclusions:Some differentially expressed snoRNAs related to α-particle induced carcinogenesis have been identified. It is predicted that the target gene of sno116-14 is involved in the biological processes such as cell proliferation, cytoskeletal structure and the signaling pathways for function regulation, providing new information for the function model of C/D box snoRNAs and the mechanism of radiation carcinogenesis.
