Multiparametric flow cytometry of human squamous cell carcinoma lines from the head and neck

Squamous cell carcinomas of the head and neck consist of heterogeneous cell populations. The purpose of the present study was to investigate whether established cell lines from human head and neck cancers under chemotherapy behaved similarly to tumors in patients during in vivo treatment. This is of interest in terms of improvements of chemotherapeutic protocols and understanding of the mechanisms of cytotoxic drug resistance. Permanent squamous carcinoma cell lines of the larynx (HLaC 78, 79), parotid gland (HPaC 79), tongue (SCC-15, SCC-25), hypopharynx (FaDu), and tumor lines with different histology and origin, as mucoepidermoid cancer cells of the submandibular gland (A 253), Epstein-Barr virus-infected human B cells (BC-1) and mouse fibroblasts (3T3) were incubated with chemotherapeutic drugs for 1 to 4 days at 37 degrees C. Despite the microscopic similarities to patient carcinomas, cancer cell lines of the head and neck showed different susceptibilities to cell kill mediated by chemotherapeutic drugs, as compared to in vivo therapeutic results with patients. The nonsquamous carcinoma lines demonstrated high chemosensitive responses after incubation with daunorubicin, cyclophosphamide, dactinomycin, vincristine, and aclarubicin. Surprisingly, only low cell killing rates in squamous carcinoma cell lines were observed after incubation with chemotherapeutic agents such as cis-platinum, 5-fluorouracil, methotrexate, or bleomycin, which are most commonly used for head and neck cancers. The results show that cytotoxic drug action on in vitro cultured squamous carcinoma cell lines of the head and neck is not representative for the in vivo responses of patient tumors. The cell lines are, however, of potential value for evaluation of cell biochemical changes associated with cytotoxic drug resistance.