Normal and malignant epithelial cells with stem-like properties have an extended G2 cell cycle phase that is associated with apoptotic resistance

摘要: Background: Subsets of cells with stem-like properties have been previously isolated from human epithelial cancers and their resistance to apoptosis-inducing stimuli has related carcinoma recurrence treatment failure. The aim this study was investigate the mechanisms agents in both normal malignant epithelia. Methods: Cells fresh head neck carcinomas (n = 11), cell lines derived neck, prostate breast 7), oral mucosa 5), were exposed various (UV, Tumour Necrosis Factor, Cisplatin, Etoposide, Neocarzinostatin). Flow cytometry for CD44 epithelial-specific antigen (ESA) expression, colony morphology, tumour sphere formation rapid adherence assays used identify subset properties. Apoptosis, cycle expression checkpoint proteins assessed (Western Blot, qPCR). role G2-checkpoint regulators Chk1 Chk2 investigated by use debromohymenialdisine (DBH) siRNA. Results: In cancer biopsies a CD44high showed increased clonogenicity, significantly lower rate apoptosis, higher proportion G2-phase cycle. An inverse correlation between percentage apoptosis found. Pulse-chase iododeoxyuridine (IdU) demonstrated that high spent longer time G2, even un-treated controls. These expressed levels G2 proteins, release BDH or siRNA apoptosis. Low passage cultures keratinocytes also found contain showing similar pattern G2-block associated apoptotic resistance. Conclusions: data indicate show greater extended phase, property is not consequence neoplastic transformation. Targeting releases these makes them more prone implying an opportunity improved therapeutic approaches.