Expression of tRF 31 in breast cancer tissues and its effect on cancer cell proliferation / 医学研究生学报

ABSTRACT

ObjectiveAt present, there are few reports on the effect of tRF 31 on breast cancer. This study aims to detect and analyze the expression level of tRF 31 in breast cancer tissues and to explore its effect on the proliferation of breast cancer cells.Methods32 tumor tissue samples and the corresponding para-cancer tissues from breast cancer patients in The Affiliated Cancer Hospital of Nanjing Medical University from November 2017 to February 2019 were collected. Six out of the thirty two samples were selected for high-throughput sequencing and at last tRF 31 (FC=6.5781, P=0.023) was selected as the research object. The expression of tRF-31 in cancer and para-cancer tissues was measured by RT-PCR. The sensitivity and specificity of tRF-31 expression in the breast cancer diagnosis were analyzed by ROC curve. Two kinds of human breast cancer cell lines (MDA-MB-231 and MCF-7) were divided into two groups control group (transfected with negative control) and tRF-31 group (transfected with tRF-31 inhibitor). The proliferation of transfected breast cancer cells was detected by CCK-8 and clonal formation assay. The expression changes of threonine kinase (AKT) and mammalian target of rapamycin (mTOR) in breast cancer cells after transfection were measured to explore the relationship between TRF-31 and AKT/mTOR signaling pathway.ResultsThe expression of tRF-31 in cancer tissues (0.103±0.207) was significantly higher than that in para-cancerous ones (0.028±0.039). ROC curve showed that the sensitivity and specificity of tRF-31 in detecting breast cancer were 90.63% and 53.13%, respectively. In MDA MB 231 cells, the expression of tRF-31 in the tRF-31 group was significantly lower than that in the control group [(0.267±0.012) vs (1±0.040), P<0.01)], and in MCF-7 cells, the expression of tRF-31 in the tRF-31 group was also significantly lower than that in the control group. In MDA-MB-231 and MCF-7 cells, the proliferation ability of the tRF-31 group was lower than that of the control group at 0h, 24h, 48h and 72h. In MDA-MB-231 cells, the clonal formation rate of tRF-31 group [(43.67±3.29)%] was significantly lower than that of the control group [(100±3.74)%] (P<0.01). In MCF-7 cells, the clonal formation rate of tRF-31 group [(49±2.94)%] was significantly lower than that of the control group [(100±4.89)%] (P<0.01). In MDA-MB-231 and MCF-7 cells, the protein levels of AKT and mTOR in tRF-31 group were significantly lower than those in the control group.ConclusiontRF-31 is highly expressed in breast cancer tissues and can promote the proliferation of breast cancer cells. This result is expected to provide a new target for the treatment of breast cancer.