title: Detecting and targeting mesenchymal-like subpopulations within squamous cell carcinomas.
abstract: Curative eradication of all cells within carcinomas is seldom achievable with chemotherapy alone. This limitation may be partially attributable to tumor cell subpopulations with intrinsic resistance to current drugs. Within squamous cell carcinoma (SCC) cell lines, we previously characterized a subpopulation of mesenchymal-like cells displaying phenotypic plasticity and increased resistance to both cytotoxic and targeted agents. These mesenchymal-like (Ecad-lo) cells are separable from epithelial-like (Ecad-hi) cells based on loss of surface E-cadherin and expression of vimentin. Despite their long-term plasticity, both Ecad-lo and Ecad-hi subsets in short-term culture maintained nearly uniform phenotypes after purification. This stability allowed testing of segregated subpopulations for relative sensitivity to the cytotoxic agent cisplatin in comparison to salinomycin, a compound with reported activity against CD44(+)CD24(-) stem-like cells in breast carcinomas. Salinomycin showed comparable efficacy against both Ecad-hi and Ecad-lo cells in contrast to cisplatin, which selectively depleted Ecad-hi cells. An in vivo correlate of these mesenchymal-like Ecad-lo cells was identified by immunohistochemical detection of vimentin-positive malignant subsets across a part of direct tumor xenografts (DTXs) of advanced stage SCC patient samples. Cisplatin treatment of mice with established DTXs caused enrichment of vimentin-positive malignant cells in residual tumors, but salinomycin depleted the same subpopulation. These results demonstrate that mesenchymal-like SCC cells, which resist current chemotherapies, respond to a treatment strategy developed against a stem-like subset in breast carcinoma. Further, they provide evidence of mesenchymal-like subsets being well-represented across advanced stage SCCs, suggesting that intrinsic drug resistance in this subpopulation has high clinical relevance.
authors.affiliation: Department of Otorhinolaryngology–Head and Neck Surgery, University of Pennsylvania, Philadelphia, PA, USA. devraj.basu@uphs.upenn.edu
authors.forename: Devraj
authors.initials: D
authors.lastname: Basu
authors.forename: Kathleen T
authors.initials: KT
authors.lastname: Montone
authors.forename: Li-Ping
authors.initials: LP
authors.lastname: Wang
authors.forename: Phyllis A
authors.initials: PA
authors.lastname: Gimotty
authors.forename: Rachel
authors.initials: R
authors.lastname: Hammond
authors.forename: J Alan
authors.initials: JA
authors.lastname: Diehl
authors.forename: Anil K
authors.initials: AK
authors.lastname: Rustgi
authors.forename: John T
authors.initials: JT
authors.lastname: Lee
authors.forename: Kati
authors.initials: K
authors.lastname: Rasanen
authors.forename: Gregory S
authors.initials: GS
authors.lastname: Weinstein
authors.forename: Meenhard
authors.initials: M
authors.lastname: Herlyn
mesh_terms: D000818:Animals; D001943:Breast Neoplasms / Q000188:drug therapy; D002294:Carcinoma, Squamous Cell / Q000188:drug therapy / Q000473:pathology*; D018929:Cell Culture Techniques; D045744:Cell Line, Tumor; D002945:Cisplatin / Q000494:pharmacology; D019008:Drug Resistance, Neoplasm / Q000187:drug effects*; D006801:Humans; D059630:Mesenchymal Stem Cells / Q000187:drug effects / Q000473:pathology*; D051379:Mice; D011714:Pyrans / Q000494:pharmacology; D014183:Transplantation, Heterologous; D000095662:Polyether Polyketides
chemical_list: D002945:Cisplatin; D011714:Pyrans; C010327:salinomycin; D000095662:Polyether Polyketides