Browsing by Author "Mehta, Fabiola F."
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Item Distinct functions and regulation of epithelial progesterone receptor in the mouse cervix, vagina, and uterus(Oncotarget, 3/17/2016) Mehta, Fabiola F.; Son, Jieun; Hewitt, Sylvia C.; Jang, Eunjung; Lydon, John P.; Korach, Kenneth S.; Chung, Sang-HyukWhile the function of progesterone receptor (PR) has been studied in the mouse vagina and uterus, its regulation and function in the cervix has not been described. We selectively deleted epithelial PR in the female reproductive tracts using the Cre/LoxP recombination system. We found that epithelial PR was required for induction of apoptosis and suppression of cell proliferation by progesterone (P4) in the cervical and vaginal epithelium. We also found that epithelial PR was dispensable for P4 to suppress apoptosis and proliferation in the uterine epithelium. PR is encoded by the Pgr gene, which is regulated by estrogen receptor ? (ER?) in the female reproductive tracts. Using knock?in mouse models expressing ER? mutants, we determined that the DNA?binding domain (DBD) and AF2 domain of ER? were required for upregulation of Pgr in the cervix and vagina as well as the uterine stroma. The ER? AF1 domain was required for upregulation of Pgr in the vaginal stroma and epithelium and cervical epithelium, but not in the uterine and cervical stroma. ER? DBD, AF1, and AF2 were required for suppression of Pgr in the uterine epithelium, which was mediated by stromal ER?. Epithelial ER? was responsible for upregulation of epithelial Pgr in the cervix and vagina. Our results indicate that regulation and functions of epithelial PR are different in the cervix, vagina, and uterus.Item Estradiol and tamoxifen regulate NRF-1 and mitochondrial function in mouse mammary gland and uterus(Journal of Molecular Endocrinology, 2014-5) Ivanova, Margarita M.; Radde, Brandie N.; Son, Jieun; Mehta, Fabiola F.; Chung, Sang-Hyuk; Klinge, Carolyn M.Nuclear respiratory factor-1 (NRF-1) stimulates the transcription of nuclear-encoded genes that regulate mitochondrial (mt) genome transcription and biogenesis. We reported that estradiol (E2) and 4-hydroxytamoxifen (4-OHT) stimulate NRF-1 transcription in an estrogen receptor ? (ER?)- and ER?-dependent manner in human breast cancer cells. The aim of this study was to determine whether E2 and 4-OHT increase NRF-1 in vivo. Here, we report that E2 and 4-OHT increase NRF-1 expression in mammary gland (MG) and uterus of ovariectomized C57BL/6 mice in a time-dependent manner. E2 increased NRF-1 protein in the uterus and MG; however, in MG, 4-OHT increased Nrf1 mRNA but not protein. Chromatin immunoprecipitation assays revealed increased in vivorecruitment of ER? to the Nrf1 promoter and intron 3 in MG and uterus 6 h after E2 and 4-OHT treatment, commensurate with increased NRF-1 expression. E2- and 4-OHT-induced increases in NRF-1 and its target genes Tfam, Tfb1m, and Tfb2m were coordinated in MG but not in uterus due to uterine-selective inhibition of the expression of the NRF-1 coactivators Ppargc1a and Ppargc1b by E2 and 4-OHT. E2 transiently increased NRF-1 and PGC-1? nuclear staining while reducing PGC-1? in uterus. E2, not 4-OHT, activates mt biogenesis in MG and uterus in a time-dependent manner. E2 increased mt outer membrane Tomm40 protein levels in MG and uterus whereas 4-OHT increased Tomm40 only in uterus. These data support the hypothesis of tissue-selective regulation of NRF-1 and its downstream targets by E2 and 4-OHT in vivo.Item Progesterone Signaling Inhibits Cervical Carcinogenesis in Mice(American Journal of Pathology, 9/5/2013) Yoo, Young A.; Son, Jieun; Mehta, Fabiola F.; DeMayo, Francesco J.; Lyndon, John P.; Chung, Sang-HyukHuman papillomavirus is the main cause of cervical cancer, yet other nonviral cofactors are also required for the disease. The uterine cervix is a hormone-responsive tissue, and female hormones have been implicated in cervical carcinogenesis. A transgenic mouse model expressing human papillomavirus oncogenes E6 and/or E7has proven useful to study a mechanism of hormone actions in the context of this common malignancy. Estrogen and estrogen receptor ? are required for the development of cervical cancer in this mouse model. Estrogen receptor ? is known to up-regulate expression of the progesterone receptor, which, on activation by its ligands, either promotes or inhibits carcinogenesis, depending on the tissue context. Here, we report that progesterone receptor inhibits cervical and vaginal epithelial cell proliferation in a ligand-dependent manner. We also report that synthetic progestin medroxyprogesterone acetate promotes regression of cancers and precancerous lesions in the female lower reproductive tracts (ie, cervix and vagina) in the human papillomavirus transgenic mouse model. Our results provide the first experimental evidence that supports the hypothesis that progesterone signaling is inhibitory for cervical carcinogenesis in vivo.Item Recurrence of cervical cancer and its resistance to progestin therapy in a mouse model(Oncotarget, 11/29/2016) Mehta, Fabiola F.; Baik, Seunghan; Chung, Sang-HyukStudies using K14E6/K14E7 transgenic mice expressing E6 and E7 oncoprotein of human papillomavirus type 16 (HPV16) have demonstrated that estrogen (E2) is required for the genesis and growth of cervical cancer. Our prior study using the same mouse model has showed that progestin drug medroxyprogesterone acetate (MPA) promotes regression of primary cervical cancer. In the present study, we use the same transgenic mouse model to determine whether the cancer recurs after MPA therapy. Cervical cancer recurred even if MPA treatment was continued. Unlike primary cervical cancer, the cancer recurred even in the absence of exogenous E2 when MPA treatment was ceased. Furthermore, recurrent cervical cancer did not fully regress upon MPA treatment. Our results support that MPA fails to completely eliminate primary cervical cancer cells and that remaining cancer cells grow independent of exogenous E2 and are refractory to MPA