Effects of delta-9-tetrahydrocannabinol on cultured HeLa cell growth and development

Monolayer cultures of HeLa cells were used to monitor the effects of non-lethal concentrations of delta-9-tetrahydrocannabinol (delta-9-THC) on the pool sizes of the acid-soluble and acid-insoluble DNA moieties and cytoplasmic RNA pool sizes. The DNA fractions were separated using acid precipitation and low speed centrifugation, while the RNA was examined through the use of sucrose gradients and high speed ultracentrifugation. The ratio of acid-insoluble to acid-soluble DNA per cell in untreated HeLa cells is 16:1, which did not change appreciably following delta-9-THC treatment. However, cell division was retarded as much as 25% in the 24 hours treatment period indicating that nucleic acid synthesis, while not inhibited, is depressed by delta-9-THC. This is not related to cell death as indicated by cell viability (> 95%). At both 1.0 x 10(-5)M and 3.2 x 10(-7)M, delta-9-THC caused a marked change in the free ribosomal RNA (an increase with 3.2 x 10(-7)M and a decrease with the 10(-5)M), total ribosomal RNA (a decrease with both observed delta-9-THC concentrations) and non-sedimental RNA (an increase with both observed delta-9-THC concentrations).