Effects And Mechanisms Of KLF4 In The Inhibition Of Proliferation Of Colon Cancer Cells By Oxymatrine

Colon cancer is one of the most common cancer of gastrointestinal tract, has become one of the fastest rising incidence of cancer, is a serious threat to people’s lives and health. Therefore, the study of the etiology and pathogenesis of colon cancer, and to find effective drugs has become an important issue of colon cancer research. Oxymatrine(OMT, molecular formula, C15H24N2O2), one kind of alkaloid components found in the roots of Sophora flavescens have various pharmacological activities and are demonstrated to have anti-virus, anti-inflammation, anti-arrhythmia, anti-fibrosis. It is recently proved to have anti-cancer potentials, such as inhibiting cancer cell proliferation, inducing cell cycle arrest, accelerating apoptosis, restraining angiogenesis, inducing cell differentiation, inhibiting cancer metastasis and invasion. OMT treatment has been shown to inhibit the proliferation of tumor cells in various cancers, including hepatoma cancer, gastric cancer, colon cancer, breast cancer, cervical carcinom, retinoblastoma and leukemia. Some studies showed OMT can inhibit the proliferation of colon cancer cells, such as HT29, LOVO, and induce apoptosis.Krüppel-like factors(KLFs) are evolutionarily conserved zinc finger-containing transcription factors with diverse regulatory functions in cell growth, proliferation, differentiation, and embryogenesis. Krüppel-like factor 4(KLF4) is belongs to the KLFs family. In particular, KLF4 has a very close relationship with the occurrence and development of malignant tumor. Studies have shown that KLF4 is low expressed in colon cancer, gastric cancer, liver cancer, skin cancer, bladder cancer tumor, and is highly expressed in primary breast cancer, prostate cancer, oral squamous cell carcinoma cancer. Remarkably, KLF4 has been described as tumour suppressor and oncogene depending on cellular context. Therefore, KLF4 might be tumor suppressor gene or a cancer gene in different tumor cells. The present studies have demonstrated that KLF4 has the ability to inhibit cell proliferation. In RKO cells, overexpression of KLF4 induces p21 expression, and causes a block in the G1/S phase of the cell cycle. After HCT116 colon cancer cell is irradiated by γ-ray, KLF4 is required to prevent centrosome amplification, if KLF4 deletion may promote chromosomal instability.Many research results have confirmed that KLF4 in the gut epithelium is an important tumor suppressor genes, but whether KLF4 involved in OMT inhibits the action of the colon cancer cell proliferation and its molecular mechanism is unclear. This project systematically study KLF4 expression level in colon cancer and colon cancer cell lines, and discuss the effect of OMT on the proliferation of colon cancer cells and the effect of KLF4 on the mechanism, and to provide a theoretical basis for further search for a therapeutic target for colon cancer.Objective:To investigate the expression level of KLF4 in colon cancer and adjacent tissues. To investigate the effect of OMT on the expression of KLF4 in colon cancer cells. To explore the mechanism of KLF4 in OMT inhibiting the proliferation of colon cancer cell.Methods:1 Collecting 30 cases of colon cancer and adjacent non-cancerous tissue,RT-PCR and Western-blot methods were respectively used to detect the expression levels of KLF4 in colon cancer and non-canceroustissue.2 HT-29 were cultured in vitro. RT-PCR and Western blot methods were used to detect the expression of KLF4 in colon cancer cells which was treated with OMT.3 Chemical synthesis of Klf4 siRNA, by transient transfecting HT-29 cells which was treated with OMT. Finally, the expression of KLF4 was down-regulationed on HT-29 cells. MTT were used to detect the ability of HT-29 cells proliferation.Results:1 Expression of KLF4 in colon cancer and adjacent tissuesRT-PCR and Western-blot methods were respectively used to detect the expression levels of KLF4 in colon cancer and adjacent tissue. The level of mRNA KLF4 and protein in colon cancer was significantly lower than that in adjacent tissues, with significant statistically difference(P<0.05).2 The effect of OMT on the expression of KLF4 in colon cancer cellsRT-PCR and Western blot methods were used to detect the expression of KLF4 in colon cancer cells which was treated with OMT. The results showed that with the increase of the concentration of KLF4, the levels of mRNA OMT and protein were significantly increased, and the relationship was significant, with significant statistically difference(P<0.05). OMT can obviously induce the expression of KLF4 in cells.3 The effect of KLF4 on the OMT inhibits the proliferation of colon cancer cellsThe KLF4 siRNA was transfected into colon cancer cell line HT-29, down-regulated expression of KLF4, and then observe the effect of OMT on the proliferation of colon cancer cells. The results showed that after we knocked down KLF4, the inhibition of OMT on the colon cancer cell proliferation significantly was significantly decreased, with significant statistically difference(P<0.05). It turned out that KLF4 mediated the procession of OMT inhibiting colon cancer HT-29 cells proliferation.Conclusion:The expression of KLF4 protein in the colon cancer is lower than that in adjacent colon tissues. OMT promotes the expression of KLF4 in colon cancer cells. KLF4 plays an important role in OMT inhibiting the proliferation of colon cancer cells.