Enhancement of transformation and continuous inhibition of intercellular communication by 1-oleoyl-2-acetyl glycerol in BALB/c 3T3 cells

Abstract

Tumour-promoting phorbol esters and diacylglycerols have a variety of biochemical and biological effects in common in a number of cell culture systems; thus, it has been suggested that diacylglycerols are endogenous functional analogues of phorbol esters. In order to examine more directly the possible relevance of these functional analogues in tumour promotion, we have studied the promoting effect of 1-oleoyl-2-acetyl glycerol (OAG) in the two-stage transformation model with BALB/c 3T3 cells, which is designed to simulate in vivo two-stage carcinogenesis. When BALB/c 3T3 cells were treated once with a low dose of 3-methylcholanthrene (MCA), almost no increase in cell transformation occurred. However, repeated application of OAG after MCA treatment enhanced cell transformation. OAG enhanced transformation to a lesser extent than a potent promoter of in vivo and in vitro carcinogenesis, phorbol-12,13-didecanoate. OAG also continuously inhibited junctional intercellular communication when BALB/c 3T3 cells were treated daily at confluence. These results indicate that diacylglycerols mimic phorbol esters in promoting cell transformation and that the enhancement may be related to an inhibitory effect on intercellular communication.