Cervical carcinoma, the second-leading cause of cancer deaths in women worldwide, is associated with human papilloma virus (HPV). Although HPV infection is widespread in the teenaged population, most case of cervical carcinoma occur 20-30 years after initial exposure. Therefore, it is likely that HPV provides an initiation step or """"""""first hit"""""""" in cervical carcinoma development. HPV-infected individuals are at high risk for developing cervical carcinoma; however, the molecular mechanisms that lead to the progression of cervical cancer have not been established. This proposal will identify a potential subsequent hit that leads to cervical carcinoma. We have detected increased cytoplasmic and nuclear 6-catenin levels in cervical carcinoma patient samples, yet mutations in the 6-catenin gene are rare in these tumors. Because 6-catenin accumulation is an indicator of activated Wnt pathway, we will study the Wnt signaling as a tumor promoting pathway. Our experimental model of cervical carcinoma uses HPV-immortalized primary human keratinocytes. In an in vitro experimental model, malignant transformation of HPV-immortalized keratinocytes can be achieved by transfecting them with SV-40 small-t antigen (smt). Our published preliminary data indicate that malignant transformation of HPV-infected primary human keratinocytes by smt involves activation of the Wnt pathway. We present preliminary data that Wnt pathway activation by Wnts and their down stream signaling components also transform HPV-immortalized keratinocytes. However, activation of the Wnt pathway in the absence of HPV infection is not sufficient to induce malignant transformation. Therefore, we hypothesize that Wnt signaling contributes to the pathogenesis of cervical cancer and causes progression to achieve malignant transformation. The following specific aims will be used to test our hypothesis;
Specific Aim 1 will determine the in vivo effect of 6-catenin stabilization in HPV-infected cervical epithelium using transgenic mouse models.
Specific Aim 2 will determine the mechanism of Wnt pathway activation in human tumor specimens of cervical cancer. Results of specific aim 1 will provide us with a clinically relevant mouse cervical carcinoma model for chemoprevention and chemotherapy. Results of specific aim 2 will lead to a better understanding of the molecular pathobiology of cervical cancer. This knowledge will allow us to identify woman at high-risk, who are more likely to progress to malignant cervical carcinoma. Results of this study can validate molecular targets in cervical carcinoma, which can be used for designing novel preventive and therapeutic strategies. ? ? ?
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