CD66 and CD49f expressing cells are associated with distinct neoplastic phenotypes and progression in human cervical cancer.

BACKGROUND: In this study, building on our recent work identifying a subset of CD66+ve cells with distinctive tumourigenic properties in human cervical cancers, we examine patterns of expression and function of these cells; to generate insights into the process of metastasis. METHODS: Our broad approach in this study has been to compare the expression and function of two subsets marked by CD66 and CD49f. We use a combination of histopathology, immunostaining and flow cytometry, functional analysis of an established cervical cancer cell line and a retrospective analysis of a cohort of cervical cancer. RESULTS: We noted CD66 expression associated with clusters of cells which are spindle shaped, SMA+ve, podoplanin+ve, phalloidin high, fibronectin high, plakoglobin low, ki67-ve and CK10+ve at the migratory phase along with features of partial EMT. Further, TGFß1 a well known regulator of EMT, positively correlated with CD66 expression. The additional CD49f+ve subset at the leading invading front of migration was SMA-ve, phalloidin low, fibronectin low, plakoglobin high, Ki67+ve and CK14+ve. These data are consistent with a role for CD66 cells in metastatic invasion with a collective cell migration process co-opting the CD49f subset. Our retrospective analysis of a cohort is consistent with a role for CD66 in metastasis. However, the broad analysis of CD66, CD49f and TGFß1 expression with patterns of overall survival points to a possible protective effect particularly for local recurrences. Hence, future studies focussing on potential heterogeneity within the CD66 subset along with the possible role of isoforms and intra-cellular roles would be essential.

CD66+ cells in cervical precancers are partially differentiated progenitors with neoplastic traits.

Cervical cancers, a malignancy associated with oncogenic papilloma viruses, remain a major disease burden in the absence of effective implementation of preventive strategies. CD66(+) cells have previously been identified as a tumor-propagating subset in cervical cancers. We investigated the existence, differentiation state, and neoplastic potential of CD66(+) cells in a precancer cell line harboring HPV31b episomes. The gene expression profile of CD66(high) cells overlaps with differentiated keratinocytes, neoplastic mesenchymal transition, cells of the squamocolumnar junction, and cervical cancer cell line-derived spheroids. There is elevated expression of DNMT1, Notch1, and the viral gene product E1⁁E4 in CD66(high) cells. Thus, CD66(high) cells, in the absence of differentiating signals, express higher levels of key regulators of keratinocytes stemness, differentiation, and the viral life cycle, respectively. We also find a striking association of neoplastic traits, including migration, invasion, and colony formation, in soft agar with CD66(high) cells. These properties and a distinct G2-M-enriched cell-cycle profile are conserved in cells from cervical cancers. Principally, using a precancerous cell line, we propose that CD66(high) cells have an intermediate differentiation state, with a cellular milieu connected with both viral replication and neoplastic potential, and validate some key features in precancer lesions. Such pathophysiologically relevant systems for defining cellular changes in the early phases of the disease process provide both mechanistic insight and potential therapeutic strategies. Collectively, our data provide a rationale for exploring novel therapeutic targets in CD66(+) subsets during cancer progression.