MicroRNAs (miRNAs) are small non-coding RNA molecules with 21 to 24 nucleotides in length, which can regulate post-transcriptional gene expression by interacting with the 3' untranslated regions of the target mRNAs. MiRNAs are widely expressed in eukaryotic cells and involved in a variety of biological processes, such as in the development, differentiation, proliferation, and apop-tosis of cells. They also play essential roles in cell cycle regulation, migration, and tumor development. MicroRNA expression varies in different human tumors and is considered a powerful potential biological indicator in the development, diagnosis, treatment, and progno-sis of cancers. Breast cancer is one of the most common malignancies, and miRNA expression has been found to be differentially ex-pressed in various types of breast cancer. The expression and function of some miRNAs involved in breast cancer development, metasta-sis, and treatments are briefly summarized in this review.

Objective:To investigate the effect of 5F on proliferation and apoptosis of human pancreatic cancer.Methods:The pcDNA3.1-PUMAAS and pcDNA3.1 were transfected into AsPC-1 cells by Lipofectamine 2000 methods,stable transfected clony was chosen through G418.AsPC-1 cells were divided into three groups:transfected pcDNA3.1-PUMAAS,transfected pcDNA3.1 and control group without transfection AsPC-1 cells.Three groups was treated with serial concentrations(8.875,37.5,142?mol/L,respectively)of 5F 10?L.MTT assay was used to observe the inhibitory actions of 5F on AsPC-1 cells.The apoptotic rate of the cells was detected by flow cytometry.And the apoptosis was assessed by Hoechst 33258 dye staining and TUNEL staining.The expression of PUMA protein was detected by Western blotting and RT-PCR.Results:The inhibitory action on cell growth was seen in AsPC-1 control cells and pcDNA3.1-cells dealing with 5F.It could also promote the occurrence of apoptosis.5F inhibited the proliferation of AsPC-1 cells in a concentration-dependent manner.The apoptosis induced by 5F was accompanied with the up-regulation of PUMA.In cells treated with 5F,the apoptosis rate decreased greatly and proliferation rate increased compared with the AsPC-1 control cells and pcDNA3.1-cells dealing with 5F.The expression of PUMA was decreased greatly comparing with pcDNA3.1-cells treated with 5F,Conclusion:5F can depress the proliferation of AsPC-1 cell in vitro,mainly through the induction of apoptosis,and it was a potential agent for pancreatic cancer chemotherapy,the mechanism was probably related to its effect on the regulation of PUMA expression.