DNA-Protein Crosslinks Formation by Benzo[a]pyrene and the Metabolites in BALB/3T3 cells

Hong, Yun Chul; Lee, Hun Jae

Abstract

Carcinogenic materials used in. occupational setting are thought to induce cancer by acting on DNA. BenzoCa)pyrene and the metabolites activated by the rat microsomal fraction were treated to the BALB/3T3 cells to see the formation of DNA-Protein Crosslinks (DPCs) and the repair. We measured the DPCs by the K-SDS assay according to Costa. The results are as follows: 1) The cytotoxicity results showed that viable cells were decreased by the increase of the dose of benzo[a]pyrene and microsomal activated metabolites and the metabolites treated cells showed more cytotoxicity. 2) The amounts of protein-crosslinked DNA in control cells are 690 ng/ml. The amounts were increased to 920 ng/ml in benzoCa)pyrene 0.1 microgram/ml treated cells, 720 ng/ml in benzo[a]pyrene 1 microgram/ml treated cells, 1,243 ng/ml in benzo[a]pyrene 10 microgram/ml, treated cells. The DPCs were measured higher in the metabolites treated cells than the benzo[a]pyrene treated cells 3) The DPCs were highest in the benzo[a]pyrene 10 microgram/ml + microsomal fraction treated cells among all treated cells. The DPCs were measured in those cells at 12 hour, 24 hour, 48 hour and 72 hour later to monitor the change of the amount of DPCs to see the repair of DPCs. The result showed that the amount of crosslinked DNA were decreased by the time. But considering the cell proliferation, the DPCs amount were not changed much and the repair did not seem to occur well.