Reversible proliferation arrest of rat 3y1 fibroblasts and selective killing of simian-virus transformed derivation of 3y1 by short-chain Fatty-acids.

We examined the effect of saturated fatty acids with carbon number from 2 to 10 on proliferation and survival of rat untransformed fibroblast 3Y1 cells and its transformed derivation induced by Simian virus 40 (SV-3Y1). Acetic acid (C2) had no effect on proliferation of these cells. Among medium-chain fatty acids (C6-C10), caproic acid (C6) showed the lowest proliferation inhibitory effect. Caprylic (C8), pelargonic (C9), and capric acid (C10) exerted killing activity to both 3Y1 cells and SV-3Y1 cells, and the toxicity increased with the elongation of their alkyl chains. The toxicity was a little greater to 3Y1 cells than to SV-3Y1 cells. In contrast, short-chain fatty acids caused reversible proliferation arrest in 3Y1 cells at 25 mM in propionic (C3), 5 mM in butyric (C4) and 10 mM in valeric (C5) acids. These short-chain fatty acids arrested 3Y1 cells not only in the GI phase but also in the G2 phase of the cell cycle. To SV-3Y1 cells, however, these short-chain fatty acids were cytotoxic. The cytotoxicity to SV-3Y1 cells was the greatest in butyric acid among short-chain fatty acid tested. These results suggest that short-chain fatty acids exert ploliferation-arresting activity against normal cells while exerting killing activity to the transformed cells.