Subcellular Accumulation of β-Carotene and Retinoids in Growth-Inhibited NCI-H69 Small Cell Lung Cancer Cells

Abstract

Delivery of β-carotene in tetrahydrofuran slowed the growth of NCI-H69 small cell lung cancer cells. Analysis of cells and cellular fractions revealed that β-carotene-treated cells accumulated β-carotene as well as some polar metabolites, primarily in the crude nuclei. Cells were grown at 1 × 105 cells/ml and treated with 20 μM β-carotene. Growth monitoring up to 15 days indicated an inverse relationship between the duration of β-carotene treatment and the rate of cell growth. Reverse-phase high-performance liquid chromatography analysis of treated cells showed the presence of β-carotene, retinoic acid, retinol, and retinal, with β-carotene accounting for the major material recovered. When cellular fractions were analyzed for β-carotene, it was found to be located primarily in the crude nuclei. These results demonstrate that treatment of small cell lung cancer cells with β-carotene results in a reduced growth of the cells. Further investigation is required to show a direct effect of β-carotene or its intracellular polar metabolites on these cells. Accumulation of β-carotene in the nucleus suggests a need for evaluating the nuclear role for β-carotene