Rab25 is a newly discovered member of the Rab11 subfamily of the Rab protein family. The purpose of this study was to investigate the proliferation of derivatives of the human breast cancer cell line MCF-7 with different levels of expression of the Rab25 gene and their tumorigenicity in nude mice. The effect of different expression levels of the Rab25 gene on various biological activities of the human breast cancer cells was also investigated. Cells in the logarithmic phase of growth were

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... ted and subcutaneously implanted into nude mice to evaluate tumor induction. The mRNA expression of Rab25 in tumors in nude mice was evaluated using quantitative RT-PCR. The results showed that stable expression of the Rab25 gene after transfection significantly increased the proliferation activity of MCF-7 breast cancer cells. The tumorigenicity in nude mice was also increased. In addition, interference with the expression of the Rab25 gene significantly inhibited the proliferation of MCF-7 breast cancer cells and attenuated their tumorigenicity in nude mice. Finally, Rab25 was discovered to be an oncogene. A high level of expression could directly increase the proliferation and invasion abilities of breast cancer cells and their tumori-genicity in nude mice. The RNA interference technology is expected to provide new approaches for tumor targeted gene therapy of breast cancer.