ESTABLISHMENT AND CHARACTERIZATION OF A NEW HPV-NEGATIVE SQUAMOUS-CELL CARCINOMA CELL-LINE (YUMOTO) FROM THE HUMAN UTERINE CERVIX

A new cell line, Yumoto, derived from a squamous cell carcinoma of the uterine cervix, was established from serially transplanted tumor tiss ues in nude mice. Monolayer cultured cells were polygonal and formed p avement-like sheet. They showed a piling-up tendency and were devoid o f contact inhibition. Electron micrographs demonstrated the presence o f microvilli on the cell surface, abundant tonofilaments in the cytopl asm, and the connection with desmosomes. These electron micrographical characteristics of Yumoto cells were consistent with those of squamou s cell origin. Yumoto cells were highly tumorigenic in BALB/c nude mic e and produced a well-differentiated squamous cell carcinoma of kerati nizing type which closely resembled to the original tumor tissues in n ude mice. The presence of HPV DNA was examined using polymerase chain reaction and Southern blot analysis, but no known types of HPV DNA cou ld be detected. Exons 2 through 11 of the p53 gene were analyzed by di rect DNA sequencing, revealing a homozygous mutation at codon 281 in e xon 8, GAC to CAC (Asp-->His). Furthermore, physical p53-gene deletion was demonstrated by dual-color fluorescence in situ hybridization. Th is cell line is useful for studying the carcinogenesis of cervical car cinoma and for investigating the biological characteristics of a HPV-n egative and mutated p53 squamous cell carcinoma of the uterine cervix. (C) 1998 Academic Press.