aphidicolin and Liver-Neoplasms

Fragile sites are classified as common or rare depending on their occurrence in the populations. While rare sites are mainly associated with inherited diseases, common sites have been involved in somatic rearrangements found in the chromosomes of cancer cells. Here we study a mouse locus containing the ionotropic glutamate receptor delta 2 (grid2) gene in which spontaneous chromosome rearrangements occur frequently, giving rise to mutant animals in inbred populations. We identify and clone common fragile sites overlapping the mouse grid2 gene and its human ortholog GRID2, lying respectively at bands 6C1 and 4q22 in a 7-Mb-long region of synteny. These results show a third example of orthologous common sites conserved at the molecular level, and reveal an unexpected link between an inherited disease and an aphidicolin-sensitive region. Recurrent deletions of subregions of band 4q22 have been previously described in human hepatocellular carcinomas. This 15-Mb-long region appears precisely centered on the site described here, which strongly suggests that it also plays a specific role in hepatic carcinogenesis.

Topics: Animals; Aphidicolin; Chromosome Aberrations; Chromosome Fragile Sites; Chromosome Mapping; Chromosomes, Human, Pair 4; Conserved Sequence; Genetic Diseases, Inborn; Humans; In Situ Hybridization, Fluorescence; Liver Neoplasms; Loss of Heterozygosity; Mice; Receptors, Glutamate

Applying Hydroxyurea, Nocodazole and Aphidicolin in succession to obtain parasynchronous growth, the progression of HTC and HeLa cells through the cell cycle has been monitored by laser flow cytometry. The experimental results show that HTC cells behave identically whether grown in monolayer or attached to dextran-based microbeads but that the chemical nature of the micro-support itself plays an important role especially on the speed with which the cells pass from mitosis into G1, polyacrylamide-based microbeads being superior in this respect.

Topics: Aphidicolin; Benzimidazoles; Carcinoma, Hepatocellular; Cell Cycle; Cell Division; Cytological Techniques; Diterpenes; Flow Cytometry; HeLa Cells; Humans; Hydroxyurea; Kinetics; Liver Neoplasms; Microspheres; Nocodazole