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. ? ? ?

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
5R01CA108641-02
Application #
7224861
Study Section
Cancer Molecular Pathobiology Study Section (CAMP)
Program Officer
Blair, Donald G
Project Start
2006-04-18
Project End
2011-02-28
Budget Start
2007-03-01
Budget End
2008-02-29
Support Year
2
Fiscal Year
2007
Total Cost
$267,492
Indirect Cost
Name
Georgetown University
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
049515844
City
Washington
State
DC
Country
United States
Zip Code
20057
Adhikari, Sanjay; Chetram, Mahandranauth A; Woodrick, Jordan et al. (2015) Germ line variants of human N-methylpurine DNA glycosylase show impaired DNA repair activity and facilitate 1,N6-ethenoadenine-induced mutations. J Biol Chem 290:4966-80
Bulut, Gülay; Üren, Aykut (2015) Generation of K14-E7/?N87?cat double transgenic mice as a model of cervical cancer. Methods Mol Biol 1249:393-406
Rahim, Said; Uren, Aykut (2011) A real-time electrical impedance based technique to measure invasion of endothelial cell monolayer by cancer cells. J Vis Exp :
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Bulut, Gülay; Fallen, Shannon; Beauchamp, Elspeth M et al. (2011) Beta-catenin accelerates human papilloma virus type-16 mediated cervical carcinogenesis in transgenic mice. PLoS One 6:e27243
Adhikari, Sanjay; Uren, Aykut; Roy, Rabindra (2009) Excised damaged base determines the turnover of human N-methylpurine-DNA glycosylase. DNA Repair (Amst) 8:1201-6
Adhikari, Sanjay; Uren, Aykut; Roy, Rabindra (2008) Dipole-dipole interaction stabilizes the transition state of apurinic/apyrimidinic endonuclease--abasic site interaction. J Biol Chem 283:1334-9
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Adhikari, Sanjay; Manthena, Praveen Varma; Uren, Aykut et al. (2008) Expression, purification and characterization of codon-optimized human N-methylpurine-DNA glycosylase from Escherichia coli. Protein Expr Purif 58:257-62
Adhikari, Sanjay; Uren, Aykut; Roy, Rabindra (2007) N-terminal extension of N-methylpurine DNA glycosylase is required for turnover in hypoxanthine excision reaction. J Biol Chem 282:30078-84