Induction of adipocyte formation in 10T1/2 cells by 1-methylguanine and 7-methylguanine.

1-Methylguanine and 7-methylguanine are naturally occurring modified purines derived from tRNA, found in elevated levels in the serum and urine of cancer patients. When C3H/10T1/2 clone-8 mouse cells are exposed to low levels of the methylated purines, they are induced to differentiate into adipocytes. Differentiation is induced in a dose-dependent manner and is similar in extent to that achieved by other inducing agents, such as 5-azacytidine. The methylated purines are not mutagenic, nor are they incorporated into DNA. They may exert their effect by modifying cellular regulatory processes, such as methylation of DNA. High levels of circulating methylated purines in cancer patients may play a role in tumor-host interactions.