Three cell lines from hamster buccal pouch tumors induced by topical 7,12-dimethylbenz(a)anthracene, alone or in conjunction with herpes simplex virus inoculation

Abstract

Three squamous carcinoma cell lines HBPC-1, HBPC-2, and HBPC-3 were established from hamster buccal pouch tumors induced by topical 7,12-dimethylbenz(a)anthracene (DMBA) treatment alone, topical DMBA treatment in conjunction with type 1 herpes simplex virus (HSV-1) inoculation, and topical DMBA application in combination with type 2 HSV (HSV-2) inoculation, respectively. The cells were epithelial in morphology, had a doubling time of approximately 18 h, and required bovine serum for optimal growth. They demonstrated an in vitro anchorage-independent growth and produced squamous cell carcinomas when transplanted into normal hamster pouch submucosa. The carcinoma cell lines equally expressed cellular hst, src, abl, and raf proto-oncogenes that were not expressed in the normal hamster pouch epithelial cells. An equal amount of fos gene expression was noticed in the normal pouch epithelial cells, HBPC-1 and HBPC-3, but the HBPC-2 expressed less fos poly(A+)RNA than the other cell lines. The myc proto-oncogene was also expressed both in the normal pouch epithelial cells and in the cancer cell lines. However, the size and number of expressed myc poly(A+)RNA in the normal cells and cancer cell lines differed. Although the normal cells and HBPC-1 expressed a single myc transcript, 1.7-kilobase (kb) and 2.3-kb, respectively, both HBPC-2 and HBPC-3 expressed two myc poly(A+)RNAs, 1.7-kb and 2.3-kb.