Δ8 and Δ9-tetrahydrocannabinol, (THC) inhibit uptake and incorporation of labelled precursors into DNA and RNA of cells in vitro. In the present study, we have exposed CCRF-CEM human lymphoblasts (log-phase and synchronized populations) to various drug concentrations. Perturbations in cell cycle traverse and the effect on DNA synthesis were monitored by flow-cytometry and autoradiography. Exposure of log-phase human lymphoblasts to various concentrations of Δ8 and Δ9 THC (2.5 x 10-5 to 10-8M) did not lead to the accumulation of cells in any specific part of the cycle and cells were blocked wherever they were in their cell cycle position. Similarly, higher drug concentrations (2.5 x 10-5M) did not show any cell cycle phase specificity for their cytotoxic action. Synchronized G1 and 5-phase cells exposed to various cytostatic and cytocidal concentrations of these agents for 24 hr showed no resumption of cell cycle traverse in the presence of the drug. Cell populations with 90% cells in S-phase were equally sensitive to the cytostatic and cytocidal effects of these agents as populations with 90% cells in G1. On the basis of these studies, we conclude that the cytostatic and cytotoxic effects of these agents are non-cycle phase specific.
|Original language||English (US)|
|Journal||Journal of Cell Biology|
|Issue number||2 II|
|State||Published - Jan 1 1977|
ASJC Scopus subject areas
- Cell Biology