Persistent infection with high-risk human papillomavirus (HPV) is a major risk factor for cervical cancer. Greater than 90% of these cancers originate in the cervical transformation zone (TZ), a narrow region of metaplastic squamous epithelium that develops at the squamocolumnar junction between the ectocervix and endocervix. It is unclear why the TZ has high susceptibility to malignant transformation and few studies have specifically examined cells from this region. We hypothesized that cells cultured from TZ are more susceptible to cellular immortalization, an alteration that contributes to malignant development. We cultured primary epithelial cells from each region of human cervix (ectocervix, endocervix and TZ) and measured susceptibility to immortalization after transfection with the complete HPV-16 genome or infection of HPV16 E6/E7 retroviruses. Cells cultured from each cervical region expressed keratin markers (keratin 14 and 18) that confirmed their region of origin. In contrast to our prediction, cells from TZ were equally susceptible to immortalization as cells from ectocervix or endocervix. Thus, increased susceptibility of the TZ to cervical carcinogenesis is not due to increased frequency of immortalization by HPV-16. We developed a series of HPV16-immortalized cell lines from ectocervix, endocervix and TZ that will enable comparisons of how these cells respond to factors that promote cervical carcinogenesis.

Persistent infection of high-risk human papillomavirus (HPV) is a major risk factor for cervical cancer. Greater than 90% of these cancers originate in the cervical transformation zone (CTZ), a narrow band of squamous metaplastic epithelium between ectocervix and endocervix. It is unclear why the CTZ has high susceptibility to malignant transformation and few studies have specifically examined cells from this region. We hypothesized cells cultured from human CTZ are uniquely susceptible to cellular immortalization and dysplastic differentiation, two alterations that contribute to malignant development. Primary epithelial cells were cultured from each region of human cervix (ectocervix, endocervix and CTZ) and characterized for expression of differentiation markers to assess their origin. We examined susceptibility of cells from each region to immortalization after transfection with the complete HPV-16 genome or infection of HPV-16 E6/E7 retroviruses. In addition, we evaluated the extent of dysplastic epithelial differentiation in organotypic cultures of HPV16-immortalized cell lines derived from each region of cervix. Our results showed that cells from the CTZ express specific keratin markers (keratin 14 and 18) that confirm their origin. Primary cell cultures from CTZ and ectocervix are more susceptible to immortalization by the HPV16 complete genome or E6/E7 retroviruses. In contrast, preliminary results indicate that HPV-immortalized CTZ and endocervical cells are more susceptible to dysplastic differentiation when maintained in organotypic culture. Our results may help to identify important signal pathways or biomarkers that are unique to cells from CTZ and that can be targeted for improved screening, prevention or therapy. Citation Format: Han Deng, Eric Hillpot, Philomina Yeboah, Sumona Mondal, Craig D. Woodworth. Susceptibility of cells from cervical transformation zone to HPV-16 induced immortalization and dysplastic differentiation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 5752. doi:10.1158/1538-7445.AM2017-5752