{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,1]],"date-time":"2026-06-01T14:56:00Z","timestamp":1780325760964,"version":"3.54.1"},"reference-count":44,"publisher":"Public Library of Science (PLoS)","issue":"2","license":[{"start":{"date-parts":[[2023,2,10]],"date-time":"2023-02-10T00:00:00Z","timestamp":1675987200000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Japan Agency for Medical Research","award":["22jk0210009"],"award-info":[{"award-number":["22jk0210009"]}]},{"DOI":"10.13039\/501100004071","name":"Khon Kaen University","doi-asserted-by":"publisher","award":["620008002"],"award-info":[{"award-number":["620008002"]}],"id":[{"id":"10.13039\/501100004071","id-type":"DOI","asserted-by":"publisher"}]},{"name":"The Program Management Unit for Human Resources & Institutional Development, Research and Innovation","award":["B05F630053"],"award-info":[{"award-number":["B05F630053"]}]},{"name":"The Post-Doctoral Training Program from Khon Kaen University, Thailand","award":["PD2562-12"],"award-info":[{"award-number":["PD2562-12"]}]},{"name":"Research and Graduate Studies, Khon Kaen University","award":["RP65-8-001"],"award-info":[{"award-number":["RP65-8-001"]}]}],"content-domain":{"domain":["www.plosone.org"],"crossmark-restriction":false},"short-container-title":["PLoS ONE"],"abstract":"<jats:p>Deregulated expression of viral <jats:italic>E6<\/jats:italic> and <jats:italic>E7<\/jats:italic> genes often caused by viral genome integration of high-risk human papillomaviruses (HR-HPVs) into host DNA and additional host genetic alterations are thought to be required for the development of cervical cancer. However, approximately 15% of invasive cervical cancer specimens contain only episomal HPV genomes. In this study, we investigated the tumorigenic potential of human cervical keratinocytes harboring only the episomal form of HPV16 (HCK1T\/16epi). We found that the HPV16 episomal form is sufficient for promoting cell proliferation and colony formation of parental HCK1T cells. Ectopic expression of host oncogenes, <jats:italic>MYC<\/jats:italic> and <jats:italic>PIK3CA<\/jats:italic><jats:sup><jats:italic>E545K<\/jats:italic><\/jats:sup>, enhanced clonogenic growth of both early- and late-passage HCK1T\/16epi cells, but conferred tumor-initiating ability only to late-passage HCK1T\/16epi cells. Interestingly, the expression levels of E6 and E7 were rather lower in late-passage than in early-passage cells. Moreover, additional introduction of a constitutively active <jats:italic>MEK1<\/jats:italic> (<jats:italic>MEK1DD)<\/jats:italic> and\/or <jats:italic>KRAS<\/jats:italic><jats:sup><jats:italic>G12V<\/jats:italic><\/jats:sup> into HCK1T\/16epi cells resulted in generation of highly potent tumor-initiating cells. Thus an <jats:italic>in vitro<\/jats:italic> model for progression of cervical neoplasia with episomal HPV16 was established. In the model, constitutively active mutation of PIK3CA, <jats:italic>PIK3CA<\/jats:italic><jats:sup><jats:italic>E545K<\/jats:italic><\/jats:sup>, and overexpression of <jats:italic>MYC<\/jats:italic>, in the cells with episomal HPV16 genome were not sufficient, but an additional event such as activation of the RAS-MEK pathway was required for progression to tumorigenicity.<\/jats:p>","DOI":"10.1371\/journal.pone.0281069","type":"journal-article","created":{"date-parts":[[2023,2,10]],"date-time":"2023-02-10T19:06:01Z","timestamp":1676055961000},"page":"e0281069","update-policy":"https:\/\/doi.org\/10.1371\/journal.pone.corrections_policy","source":"Crossref","is-referenced-by-count":5,"title":["An in vitro carcinogenesis model for cervical cancer harboring episomal form of 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