CXC chemokine receptor 4 regulates breast cancer cell cycle through S phase kinase associated protein 2 / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To investigate the effect of CXC chemokine receptor 4 (CXCR4) on cell cycle of breast cancer and its molecular mechanisms.</p><p><b>METHODS</b>The expression of CXCR4 and S phase kinase associated protein 2 (Skp2) was detected by real-time fluorescence quantitative PCR (fqRT-PCR) and Western blot in breast cancer cells. The expression of signal proteins and the downstream genes of Skp2 was detected by Western blot. The effect of CXCR4, PI3K/Akt pathway inhibitor LY294002 and ERK pathway inhibitor U0126 on cell cycle of breast cancer was detected by propidium iodide staining.</p><p><b>RESULTS</b>Skp2 was significantly down-regulated in CXCR4-downregulated cells and up-regulated in CXCR4-upregulated cells. CXCR4 also regulated the expression of Skp2 and other downstream genes by signaling protein. The proportion of cells in G/Gphase increased and that in S phase declined in CXCR4-downregulated cell, and the effect was more significant when combined with the use of LY294002 or U0126.</p><p><b>CONCLUSIONS</b>CXCR4 can affect cell cycle and inhibit the proliferation of breast cancer cells by regulating Skp2 gene expression through PI3K/Akt and ERK signaling pathway.</p>

Effects of lncRNA RP11-770J1.3 and TMEM25 expression on paclitaxel resistance in human breast cancer cells / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To investigate the effects of long non-coding RNA(lncRNA) RP11-770J1.3 and transmembrane protein 25 (TMEM25) on paclitaxel resistance in human breast cancer MCF-7/PR cell line.</p><p><b>METHODS</b>The expression of lncRNA RP11-770J1.3 and TMEM25 in human breast cancer MCF-7(paclitaxel sensitive) and MCF-7/PR(paclitaxel resistant) cells were detected by quantitative RT-PCR. The synthetic interfering fragments of lncRNA RP11-770J1.3 and TMEM25 were transfected into MCF-7/PR cells. Sulforhodamine B assay was used to detect the sensitivity of MCF-7/PR cells to paclitaxel after interference of lncRNA RP11-770J1.3 and TMEM25. The expression of multidrug-resistance genes and proteins were detected by qRT-PCR and Western blot, respectively.</p><p><b>RESULTS</b>lncRNA RP11-770J1.3 and TMEM25 were highly expressed in MCF-7/PR cells, and were significantly down-regulated after transfection of synthetic interfering fragments. Down-regulation of lncRNA RP11-770J1.3 and TMEM25 enhanced the sensitivity of MCF-7/PR cells to paclitaxel, and inhibited the expression of MRP, BCRP and MDR1/P-gp (all<0.05). Such effects were more significant when lncRNA RP11-770J1.3 and TMEM25 were both down-regulated (all<0.05).</p><p><b>CONCLUSIONS</b>lncRNA RP11-770J1.3 and TMEM25 are highly expressed in MCF-7/PR cells, and the down-regulation of lncRNA RP11-770J1.3 and TMEM25 can enhance paclitaxel sensitivity in MCF-7/PR cells.</p>

Study of the RNA interference silencing of survivin gene and chemosensitivity to docetaxel in MCF-7 cells / 中国药理学通报

Aim Through interfering the expression of survivin with short hairpin RNA(shRNA) technology,to investigate the effect of downregulation of survivin on cell apoptosis and chemosensitivity to docetaxel in breast cancer MCF-7 cells.Methods(1) Using MCF-7 cells as a model system,three groups were set up transfected with lipofectamine,RNAi control plasmid and survivin RNAi plasmid,respectively.The expression of survivin in MCF-7 cells was measured at transcriptional and translational level by using RT-PCR and Western blot methods.(2) The effect on the cell cycle and apoptosis was analyzed with flow cytometry.(3) The viability of cells applied with different doses of ducetaxel was determined by using the method of 3-[4,5-Dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide reduction(MTT method).Results(1) RT-PCR and Western blot demonstrated that survivin expression was significantly decreased by transfection with RNAi targeting plasmid;the expression proportion was reduced by nearly 75.4% and 79.8%(P