Characterization Of The Regulatory Mechanism Of Human Papillomavirus Type16E7and The Functionality Of Missing In Metastasis Gene

Tumor progression is a multistep process consisting at least of abnormal proliferation, transformation, invasion into normal tissues and metastasis, the last of which often leads to ultimate mortality. Numerous genetic changes and a variety of positive and negative factors have been implicated in these individual steps. However, how these factors contribute to tumor progression, in particularly metastasis, remains poorly illustrated. Therefore, characterization of the functions of these factors should provide insights into the biological and mechanical basis of cancer development. This dissertation was focused on two genes that are intimately implicated in cancer progression, human papillomavirus type16E7(HPV16E7) and missing in metastasis gene (MIM or MTSS1).Cervical cancer is the second common cancer among women in the world. There is increasing evidence for the association of high-risk types of human papillomaviruses with more than90%of cervical cancers. Our previous study indicated that HPV16E7virus causes down-regulation of MHC Class I expression with an unknown mechanism. In this study, we demonstrated that HPV16E7protein is associated with the promoter of the MHC class I gene at a putative RXRP binding site (GGTCA) through reporter transcriptional and CHIP assays. Such association causes partial decrease in the activity of the HLA-A2promoter. Our data also provide evidence that HPV16E7inhibits TNF-a induced up-regulation of MHC class I transcription through a mechanism that involves impaired nuclear translocation of NF-κB. FACS assay further indicated a significant increase in the expression of MHC class I in CaSki cells treated with TSA or transfected with IKKA. This result implicates a novel mechanism for the role of HPV E7in cervical carcinogenesis, which involves its association with the MHC class I promoter and improper NF-κB nuclear translocation that leads to up-regulation of TNF-a induced MHC class I expression.Hematopoietic stem progenitor cells (HSPCs) possess the intrinsic capacity to self-renew and to reconstitute multi-lineage hematopoietic cells in lethally-irradiated humans and animals and thus have been widely used clinically to regenerate lympho-hematopoiesis after curative radio-chemotherapy for hematologic malignances and certain non-malignant disorders. Successful engraftment of HSPCs and repopulation of blood cells is dependent upon the ability of intravenously administrated stem cells to migrate (homing) into the medullary cavity of the bone marrow (BM) and to be retained in the appropriate marrow niche where they interact with one or several specialized microenvironmental cells, e.g. osteoblasts, endothelial cells, SDF-expressing reticular cells and nestin expressing mesenchymal stem cells.In this study, we prepared MIM knockout mice by utilizing an embryonic stem cell line carrying a gene trapping vector and further used FASC to track different populations of HSPC after transplantation of BM cells derived from MIM knockout mice into lethally irradiated mice. The result shows that the BM cells with depletion of MIM have acquired a significant increase in the homing ability after short-term transplantation, indicating that MIM may be suitable for using as a target to develop a new therapy to improve homing of HSPC after transplantation. We also designed two short peptides able to interfere with the function of MIM through interrupting of MIM dimerization. The results of the data indicate that the dimeric configuration is essential for MIM-mediated membrane remodeling, which may underlie a molecular mechanism for the function of MIM in the mobility of HSPC.