Effects Of IL-8 Gene On The Growth Of Human Cervical Cancer Transplanted In Nude Mice And Its Possible Mechanisms

Objective: Carcinoma of the uterine cervix is the second commonest female cancer worldwide, The Prevalence lies in first Place in our country (China) [1].The areas of its high occurance are all connected with each other and people who develop it are at a much younger age than before[2]. It become one of the main disease which severely threaten health of women in our country. The genesis and development of uterine cervix cancer is a procedure that become from quantitative change to qualitative alteration and from anamorphosis to mutation. Local infiltration and lymph node metastasis not only influence operation effect but also direct to the prognosis. Lymph node metastasis is the main route of metastasis of uterine cervix cancer,and takes place early. It has been reported that the five-year survival rate of the patients who had no lymph node metastases was 82.2% and the patients who had lymph node metastasis was 50.8%[3].Although the study in the treatment of UCC has continued hundred of years, the result is very striking, five-year survival rate of early UCC have not reach 90%-100%. In recent years, with cell engineering and generic engineering technology development, tumor immunotherapy has been rapidly developed. Cytokine gene therapy become a hot research.IL-8 is the first chemotatic factor that discovered by Yoshimur[4] in 1987. IL-8 promote the hyperplasia and immigration of tumour cell[5].Along with the investigation in mechanism of IL-8 and acceptors deeply, hinted that IL-8 play an important role in the development of tumer. IL-8 receptors exist in many types of cells,even including some of the cells which did not express IL-8. They mainly include two types: IL-8RA and IL-8RB. PCNA(Proliferating cell Nuclear Antigen) is one of the best known endogenous proliferation markers. PCNA expression appeared to more directly correlate with the presence of proliferating cells. The abnormal expression of PCNA may be involved in the pathogenesis and development of cervical cancer. In recent years, nude mice model transplanted with human cancer has become the main tool of the study of the biological characteristics of cancer and screening of anti-cancer drugs. To get IL-8 transplanted cervical cancer, we establish animal model of transplantated tumor; Expression of IL-8RA and IL-8RB in the cervical tumor tissue of the three groups, was detected by using semiquantitative RT-PCR; The expression of PCNA was examined by S-P immunohistochemical method . In order to provide a new index of diagnosis and treatment and prognosis judgment of cervical cancer, we study the effects of exogenous IL-8 expression on the growth of human cervical cancer transplanted in nude mice and its possible mechanisms.Methods:1 Specimens : Stable expression of IL-8 in cervical cancer cell lines Hela/hIL-8 cell,Hela/pcDNA3.1(+) cell and Hela cell are given by Animal Experimental Center of Hebei Medical University. Laboratory animal: SPF (specific pathogen free) level feamale nude mouse, 4-6weeks, 16-18g weight, purchased from Animal Center of Beijing union.2 Establish animal model of transplantated tumor. Female nude mouse are divided into Hela/hIL-8 group, Hela/pcDNA3.1(+)group and Hela group, and injected diffrent cell suspension 0.2ml(total cellular score is 5×106) into the back of mouse.3 Observe the time of the tumour appears and the growth of tumour, measure tumor size weekly, kill the mice and get tumour after 9 weeks. The volume of tumour in each group was compared in different time.4 Semi-quantitative RT-PCR: The present study was performed to detect the expression of IL-8RA and IL-8RB in the cervical tumor tissue of the three groups,then analyzed the results.5 Immunohistochemistry was performed by using the S-P method. We sued anti-PCNA(1:100 dilution) to detect the expression of PCNA protein in samples, then analyzed the results. 6 HE staining : We used HE staining to detect the incidence of lung metastasis in Hela/hIL-8 group,Hela/pcDNA3.1(+)group and Hela group.Result:1 Establish animal model of transplantation tumor successfully by Hela/hIL-8 cells,Hela/pcDNA3.1(+) cells and Hela cells.2 The effects of exogenous IL-8 expression on the growth of human cervical cancer transplanted in nude mice: Compared with other groups, tumour volume of IL-8 group is much larger than Hela/pcDNA3.1(+)group and Hela group. It have statistical significance(P<0.05). Days of tumour growth of Hela group, empty plasmid group and IL-8 group is 19.70±1.25, 19.90±1.28, 16.00±1.53. Rate of tumor growth is 100%. Tumor volume of Hela/hIL-8 group is much bigger than Hela/pcDNA3.1(+)group and Hela group in 7, 8, 9 week . It have statistical significance(P<0.05). There have no difference in other times.3 Semi-quantitative RT-PCR: In the present study, we examined the expression of IL-8RAmRNA and IL-8RBmRNA in the Hela/hIL-8 group, Hela/pcDNA3.1(+)group and Hela group. No significant difference was found (P>0.05 ).4 The immunohistochemical result of PCNA. The PCNA in Hela/hIL-8 group was much higher than other two groups. Light absorption value of PCNA of Hela group, empty plasmid group and IL-8 group are 0.0794±0.0098, 0.0812±0.0100, 0.1072±0.0049. There was statistical significance(P<0.05).5 Cancer cells couldn't found in lung in each group.Conclusion:1 Nude mice model transplanted with human cancer could simulate the state of cervical cancer in the body .2 Hela/hIL-8 cells can explicitly promote the proliferation of cervical tumor.3 IL-8 promote the proliferation of cervical cancer cells through the way of enhancing the express of PCNA.4 IL-8 promote the growth of cervical cancer may through the way of binding with IL-8 receptor A and B, but it can not let IL-8 receptors express more.5 PCNA may be used as tumor marker in the diagnosis, treatment and prognostic evaluation.6 IL-8 gene is expected to become targets of gene therapy for cervical cancer.