Expression Of ORAOV1 In Human Colon Cancer And Its Significance

BackgroundColon cancer(CRC,colorectal cancer)is the one of the highest incidence and diagnosis rate of malignant gastrointestinal tumors occurs in people between the ages of 50-65.According to WHO statistics,the annual increase incidence of colon cancer is nearly one million patients in the global,and every year about 60 million people died of colon cancer.Global statistics indicates that: For men,incidence of colon cancer,followed by lung cancer and prostate cancer,was the third place.While for women,it is located in the second malignant tumors.Great threat of colon cancer to human health,extremely serious affects to the patient's health and quality of life.Results of epidemiological survey have found that the influence factors of colon cancer between developing countries and developed countries is not the same and of significant regional.For East Asian countries,the incidence of colon cancer is accompanied with obesity consumption of bacon,smoking and other factors.However the molecular mechanisms of the CRC has not yet been elucidated.The phenomenon of chromosome 11q13 region amplification was widely present in various types of tumor,such as hepatoma,stomach and especially colon cancer and other digestive tumors.It is closely related with tumor metastasis and prognosis.Oral cancer overexpressed sequence 1(ORAOV1,oral cancer overexpressed protein 1),also known as tumor overexpressed sequence 1(Tumor Amplified and overexpressed sequence 1),which located within chromosome 11q13.3 region,is adjacent to the Cyclin D1 gene.ORAOV1 is originally found in oral epithelial tumors,further investigations found that ORAOV1 was also highly expressed in digestive tumors such as hepatoma,gastric cancer,and pancreas cancer.Previous studies have shown that Cyclin D1 overexpression exists in colon cancer.What's more,excessive 11q13 amplification also plays a crucial part in the development of colon caner.However Cyclin D1 overexpression can not fully explain the molecular mechanisms of the development of colon cancer.Considering that the location of ORAOV1 is closely to Cyclin D1,some studies have revealed that both Cyclin D1 and ORAOV1 amplification simultaneously exists in some type of cancers,such as esophageal cancer.Therefore,we hypothesized that ORAOV1 expression may be altered in colon carcinoma,and it may participate the development or regulates the biological behavior of colon cancer cells.To verify these above assumptions,we aimed to detect ORAOV1 expression in both colon cancer tissue,and para-cancer tissue further to investigate the function of ORAOV1 in colon cancer cell proliferation.We hope our study could help to clarify the occurrence and development of colon cancer molecular mechanisms and to provide potential therapeutic targets.ObjectiveTo study whether ORAOV1 is related with colon cancer.Methods1.First we collected of colon cancer tissue and tissue adjacent to carcinoma from colon resection patients.Our study have been approved by The Third Military Medical University,Third Affiliated Hospital Ethics Committee and patients and their families.From June 2014 to June 2015,we collected colon cancer tissues in Department of general surgery Daping hospital.The collected samples were then cut into the bean size,then stored in liquid nitrogen,a small part of the tissue was used to paraffin-embedded conservation,followed by histopathological examinations to identify whether the collected tissues were colon carcinoma tissue.2.To research ORAOV1 expression in colon cancer:(1)extracted RNA from colon cancer tissue and adjacent tissues,followed by reverse transcription,then to test ORAOV1 expression on the m RNA levels;(2)extract total protein from colon carcinoma and adjacent tissues to study whether the expression of ORAOV1 was increased on the protein level.3.Utilize Lo Vo and SW480 colon cancer cell lines to study the effect of ORAOV1 in the biological behavior of colon cancer cells: Construction of p GPU6/ GFP / Neo-sh-ORAOV1 plasmid and its corresponding control plasmid,then transfected them respectively into Lo Vo and SW480 cells to conduct transient transfected cell lines;CCK8 test and flow cytometry experiments were used to detect cell proliferation and apoptosis,to make sure that cell proliferation and apoptosis is closely related with ORAOV1 genes.Results1.ORAOV1 is overexpressed in the colon caner compared with paracancerous tissue.2.The experiment of CCK8 shows that when the expression of ORAOV1 silence,the proliferation of Lo Vo and SW480 cell lines was arrested.3.The experiment of Flow cytometry detection shows that,compared to the normal colon cells,when expression of ORAOV1 was interfered,there were more sistage arrest and more apopeosis.ConclusionORAOV1,which is up-regulated in colon cancer tissue,could promote the proliferation of SW480 and Lo Vo cells,by inhibiting cell cycle arrest and apoptosis.