Mechanism of action of alpha-methylene-gamma-lactone derivatives of substituted nucleic acid bases in tumour cells.

Some alpha-methylene-gamma-lactone derivatives of substituted nucleic acid bases, which showed significant antitumour activity against experimental tumours, were tested for their possible mechanism of action. Derivatives 1, 4 and 7 strongly inhibit active transport of uridine through sarcoma-180 ascites tumour cells. Derivatives 1, 7 and 10 strongly inhibit a translation process in these cells, besides apparent inhibition in transcription. It appears that active transport and translation might be the primary steps inhibited by these drugs.