The Effect And Mechanism Of MCL1 On Biological Behavior Of High Grade Serous Ovarian Carcinoma

Background:Ovarian cancer is the highest mortality rate of female reproductive system tumors.High grade serous Ovarian cancer is the common subtype of high invasive ovarian cancer,and the majority of patients have been diagnosed with advanced stage, the tumor has been widely transferred. The current surgical treatment and chemotherapy can reduce the tumor load to a certain extent, but have no significant effect on the long-term survival rate of patients. Therefore, it is very important to explore the occurrence and development of ovarian cancer.Myeloid cell leukemia-1 (MCL1) has the BCL2 homologous regions, and its function is similar to those of BCL2 protein, which can inhibit cell apoptosis. MCL1,as regulatory gene of apoptosis, when it expresses imbalance can promote the tumor formation, proliferation, and promoting the resistance of tumor cells to drug induced apoptosis.Epithelial-mesenchymal transitions (EMT), it is the process that the epithelial cells are transformed into mesenchymal cells, which can obtain the phenotype of mesenchymal cells. And this process requires a variety of biochemical changes, is the process of epithelial cells into mesenchymal cells.EMT is not only involved in embryonic development, tissue remodeling and wound healing process, but also is important to the development and metastasis of tumor. Cell surface adhesion molecules in the process of EMT decreased, cell adhesion ability decreased, invasion and migration ability increased, and promote the metastasis of cancer cells. During the process of EMT, cells lose epithelial adhesion molecules (such as E-cadherin)and acquire mesenchymal markers(such as N-cadherin), with increased migration and invasion. In vitro and in vivo studies have shown that EMT play a role in epithelial tumor invasion and dissemination process, is key molecular events in the invasion of tumor cells of epithelial origin, play an important pathogenic role in the process of development and metastasis of malignant tumor.So far,there is no evidence to show that MCL1 can affect the invasion and migration of ovarian cancer cells. In this study, the biological role and mechanism of MCL1 gene in ovarian cancer were studied, and the effect of MCL1 on invasion and migration of ovarian cancer cells and its mechanism were also explored.Methods:(1)Use immunohistochemical staining method to detect the expressions of MCL1 protein in 63 cases of ovarian cancer tissues, and analyze the correlation expressions of MCL1 protein with prognosis.(2) Western blot to examine the expression of MCL1 in HGSOC and normal fallopian tube tissue.(3) Establish stable over and short espression ovarian cancer cell line by virus. (MCL1-OVE-A2780 and MCL1-OVE-SKOV3 and control,; shMCL1 A2780 and shMCLl-HEY and control)(4) Use the stable expression ovarian cancer cell line to experiment the change of proliferation,drug sensitivity(CDDP)and invasion and migration ability.(5)Western blot:use the stable expression ovarian cancer cell line as the foundation,to test the influences of markers of EMT at protein levels.(6) Intraperitoneal injection cancer cell lines to observe the difference of tumorigenesis and metastasis in vivo nude mice between overexpression MCLland control group.Results:(1) High expression of MCL1 is associated with poor prognosis in HGSOC (P=0.0089). And the expression level of MCL1 was significantly correlated with the level of CA125 and lymph node metastasis (P=0.032, P=0.041).(2) Compared with normal fallopian tubes, the expression of MCL1 was significantly higher in HGSOC, and the expression of MCL1 in different ovarian cancer cell lines was generally higher than that in the normal fallopian tube.(3) The successful construction of stable interference and over expression of ovarian cancer cell lines and through the cell experiments confirmed that MCL1 enhanced the proliferation ability of ovarian cancer cells and reduce the sensitivity to chemotherapeutic drugs and promote the invasion and metastasis of ovarian cancer cells.(4) MCL1 promote epithelial mesenchymal transition of ovarian cancer cells, and manipulation of MCL1 modulates E-cadherin and N-cadherin expression and influences other markers of EMT at protein levels.(5) Intraperitoneal injection experiment showed:compared with the control group, the expression of MCL1 ovarian cancer cell line was significantly increased in the number of peritoneal metastasis, metastatic tumor volume.Conclusion:(1) MCL1 was highly expressed in HGSOC, and its high expression was closely related to the poor prognosis of ovarian cancer.(2) High expression of MCL1 is related to the malignant biological behavior of ovarian cancer, which can enhance the ability of ovarian cancer cell proliferation, decrease the sensitivity to chemotherapeutic drugs, and enhance the ability of invasion and metastasis of ovarian cancer.(3) One of the mechanisms of MCL1 in the invasion and metastasis of ovarian cancer is EMT.