Effect of circTHBS1 on Malignant Biological Behaviors of Breast Cancer Cells by Regulating miR-135a-5p/RAB1A Axis
ZHANG Hongxu1, LIU Haiwang2, WANG Minghui1, LIU Hancheng1, ZHAO Heyu1, MA Lihui1*
This study aims to investigate the effect of circTHBS1 (circular RNA thrombospondin-1) on the ma lignant biological behaviors of BC (breast cancer) cells by regulating the miR-135a-5p (microRNA-135a-5p)/RAB1A (Rab family protein 1A) axis. qRT-PCR (real-time fluorescence polymerase chain reaction) was used to detect the expression of circTHBS1, miR-135a-5p, and RAB1A mRNA in BC cell lines, and the optimal cell line was screened for subsequent experiments. MCF-7 cells were grouped into Control group, sh-NC group, sh-THBS1 group, sh-THBS1+inhibitor NC group, and sh-THBS1+miR-135a-5p inhibitor group. qRT-PCR was used to detect transfection efficiency. Dual lucifer ase reporter gene method was used to confirm the interaction between circTHBS1 and miR-135a-5p, miR-135a-5p and RAB1A. Western blot assay was used to detect the expression of RAB1A in MCF-7 cells. Plate cloning method was used to detect the proliferation of MCF-7 cells. Flow cytometry was used to detect the apoptosis of MCF-7 cells. Scratch as say was used to detect the migration of MCF-7 cells. Transwell method was used to detect the invasion of MCF-7 cells. The nude mouse transplantation tumor experiment was used to detect the effect of circTHBS1 on the growth of BC cells in tumor tissue. The dual luciferase reporter gene assay found a targeted relationship between circTHBS1 and miR-135a 5p, RAB1A and miR-135a-5p. Compared with normal breast epithelial cells MCF-10A, the expression of circTHBS1 and RAB1A obviously increased in BC cell lines, while the expression of miR-135a-5p obviously decreased (P<0.05). Knock ing down the expression of circTHBS1 was able to inhibit the proliferation, migration, and invasion of MCF-7 cells, and induce MCF-7 cell apoptosis (P<0.05). Inhibiting the expression of miR-135a-5p was able to reverse the inhibitory effect of knocking down circTHBS1 expression on the proliferation, migration, and invasion of MCF-7 cells, and inhibit MCF-7 cell apoptosis (P<0.05). Through nude mouse transplantation experiments, it was found that knocking down the expression of circTHBS1 resulted in a decrease in the mass and volume of BC tumor tissue in nude mice, and a decrease in RAB1A expression and an increase in miR-135a-5p expression (P<0.05). circTHBS1 is highly expressed in BC cells. Knocking down circTHBS1 can inhibit the malignant biological behaviors of BC cells by regulating the miR-135a-5p/RAB1A axis.
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