Subcellular accumulation of beta-carotene and retinoids in growth-inhibited NCI-H69 small cell lung cancer cells

Delivery of beta-carotene in tetrahydrofuran slowed the growth of NCI-H69 s mall cell lung cancer cells. Analysis of cells and cellular fractions revea led that beta-carotene-treated cells accumulated beta-carotene as well as s ome polar metabolites, primarily in the crude nuclei Cells were grown at 1 x 10(5) cells/ml and treated with 20 mu M beta-carotene. Growth monitoring up to 15 days indicated an inverse relationship between the duration of bet a-carotene treatment and the rate of cell growth. Reverse-phase high-perfor mance liquid chromatography analysis of treated cells showed the presence o f beta-carotene, retinoic acid, retinol, and retinal, with beta-carotene ac counting for the major material recovered When cellular fractions were anal yzed for beta-carotene, it was found to be located primarily in the crude n uclei. These results demonstrate that treatment of small cell lung cancer c ells with beta-carotene results ill a reduced growth of the cells. Further investigation is required to show a direct effect of beta-carotene or its i ntracellular polar metabolites on these cells. Accumulation of beta-caroten e in the nucleus suggests a need for evaluating the nuclear role for P beta -carotene.