CHL1 Is Involved In Human Breast Tumor Proliferation And Migration

Aim: To investigate the expression of CHL1 in breast cancer tissue and related cells and explore the influence of CHL1 on the proliferation and invasion of breast cancer cells.Methods: 30 primary breast cancer patients who were diagnosed in Provincial Hospital Affiliated to Shandong University in 2012 were chosen. All of the patients were not accepted chemotherapy and radiotherapy before operation. The m RNA expression level of CHL1 in breast cancer tissue and cells was detected by Real-time PCR, meanwhile the protein level was detected by Western blot. The CHL1 coding sequence was amplified by polymerase chain reaction by using c DNA library derived from MCF10 A cells and the template was subclonde into vector to construct recombinant plasmids pc DNA3.1-CHL1. The recombinant plasmids pc DNA3.1-CHL1 was transfected into MDA-MB-231 cells by using Lipofectamin TM 2000, in order to make CHL1 overexpression. CHL1 expression in MCF-7 was knocked down by infected CHL1-si RNA-1 and CHL1-si RNA-1. The influence of CHL1 on cell proliferation ability was measured using MTT assay and Soft AGAR cloning formation assay, and the influence on invasion ability was by Transwell assasy. Sh RNA-CHL1-lentivirus was infected into MCF-7 cell line, to make CHL1 expression level knocked down stablely. We then injected these cells into SCID mice subcutaneously(1×107 per mouse) to evaluate the effect of altered CHL1 expression level on xenograft tumor.Result: 1. Compared with normal breast tissue, the m RNA and protein level of CHL1 was downregulated, and related to upper grade. 2. CHL1 was down-regulated in human breast cancer cells(MCF-7, MDA-MB-231,MDA-MB-435, T47D), compared with human mammary epithelial cell MCF10 A. 3. Compared with the parental and control cells, CHL1 over-expression significantly decreased MDA-MB-231 proliferation ability; CHL1 lacking significantly promote MCF-7 proliferation ability(P<0.05). 4. Compared with the parental and control cells, CHL1 over-expression significantly decreased MDA-MB-231 invasion ability; CHL1 lacking significantly promote MCF-7 invasion ability(P<0.05) 5. Compared with the parental and control cells, tumor formation and tumor growth of CHL1 deficency cells were significantly increased in SCID mice.Conclusions: The expression of CHL1 were universally low both in breast cancer tissue and breast cancer cells; CHL1 is critical in suppressing the proliferation and invasion of human breast cancer cells...