ABSTRACT
Objective:To investigate the effect of miR-26b on the invasion and migration of lung cancer cell and to explore its mechanism.Methods:qPCR was used to detect the expression of miR-26b in lung cancer.Luciferase reporter gene was used to detect interaction between miR-26b and hENT1.Transwell assay was used to detect invasion ability after treatment of miR-26b mimics.Scratch assay was used to detect migration ability after treatment of miR-26b mimics.The expressions of hENT1,ROCK-I and RhoA were detected by Western blot.The changes of cytoskeleton after miR-26b mimics treatment with phalloidin were observed.The effect of miR-26b mimics on the tumor size and volume of lung cancer was determined by subcutaneous tumor formation in nude mice.Results:MiR-26b expression was significantly reduced in lung cancer.With the progress of lung cancer,the expression of miR-26b was reduced.With the progress in differentiation of lung cancer,the expression of miR-26b was decreased.Decrease of miR-26b was associated with lung cancer lymph node metastasis.HENT1 was the direct target of miR-26b;miR-26b regulated the invasion and migration ability of human lung carcinoma A549 cells.MiR-26b regulated the expression of hENT1,ROCK-1 and RhoA.After the treatment with miR-26b mimics,the F-actin staining was significantly reduced,whereas the formation of wrinkles and the formation of pseudopodia were significantly reduced.Subcutaneous tumor formation in nude mice showed that miR-26b mimics treatment significantly reduced the tumor size and mass.Conclusion:MiR-26b plays a role in tumor suppression in lung cancer.miR-26b can regulate the invasion and migration ability of lung carcinoma A549 cells by targeting hENT1 depending on the RhoA/ROCK-1 pathway.
ABSTRACT
Pituitary tumor-transforming gene-1 (PTTG1) is a proto-oncogene that promotes tumorigenesis and metastasis in numerous cell types and is overexpressed in a variety of human tumors. We have demonstrated that PTTG1 expression was up-regulated in both human prostate cancer specimens and prostate cancer cell lines. For a more direct assessment of the function of PTTG1 in prostate tumorigenesis, RNAi-mediated knockdown was used to selectively decrease PTTG1 expression in PC3 human prostate tumor cells. After three weeks of selection, colonies stably transfected with PTTG1-targeted RNAi (the knockdown PC3 cell line) or empty vector (the control PC3 cell line) were selected and expanded to investigate the role of PTTG1 expression in PC3 cell growth and invasion. Cell proliferation rate was significantly slower (28%) in the PTTG1 knockdown line after 6 days of growth as indicated by an MTT cell viability assay (P < 0.05). Similarly, a soft agar colony formation assay revealed significantly fewer (66.7%) PTTG1 knockdown PC3 cell colonies than control colonies after three weeks of growth. In addition, PTTG1 knockdown resulted in cell cycle arrest at G1 as indicated by fluorescence-activated cell sorting. The PTTG1 knockdown PC3 cell line also exhibited significantly reduced migration through Matrigel in a transwell assay of invasive potential, and down-regulation of PTTG1 could lead to increased sensitivity of these prostate cancer cells to a commonly used anticancer drug, taxol. Thus, PTTG1 expression is crucial for PC3 cell proliferation and invasion, and could be a promising new target for prostate cancer therapy.