Characterization of cultured cells derived from Mongolian gerbil's (Meriones unguiculatus) ascitic malignant melanoma.

Abstract

A cell line was established from a Mongolian gerbil's (Meriones unguiculatus) homotransplantable malignant melanoma. Ascitic tumor cells detected in a gerbil when transplanted intraperitoneally were adapted to culture. In primary culture, cells were divided into 2 types, multipolar and polygonal cells. Cell masses which adhered to polygonal cells were observed after the 6th passage. The adhering cells were removed and transferred into another flasks. The cells showed multipolar and possessed projections. Then after, the cells increased in number vigorously and formed acinous structures. At early passages, abundant melanin granules in some of the cells were demonstrated by light and electron microscopical observations. Most of the cells were positive by DOPA reaction. Melanin pigments were gradually decreased through the 20th to 30th passage and most of cells became amelanotic. The doubling time of the cell line was 32 hr. Chromosome number of the cell line ranged from 68 to 82. Whitish tumors were produced in the abdominal cavity within 30 days when intraperitoneally inoculated the cells to gerbils. This cell line, designated as MGM-A, has been subcultured for more than 100 passages during 2 years.