Relative uptake of tomato carotenoids by in vitro intestinal and prostate cancer cells

Authors: MORAN, NANCY - Children'S Nutrition Research Center (CNRC); ALEXANDER, BRIANNA - Children'S Nutrition Research Center (CNRC); GARG, SHIVI - Children'S Nutrition Research Center (CNRC); MARCHANT, NATHAN - Baylor College Of Medicine; HASON, NOOR - Children'S Nutrition Research Center (CNRC)

Submitted to: Journal of Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/4/2024
Publication Date: 10/10/2024
Citation: Moran, N.E., Alexander, B., Garg, S., Marchant, N., Hason, N.A. 2024. Relative uptake of tomato carotenoids by in vitro intestinal and prostate cancer cells. Journal of Nutrition. 154(12):3639-3651. https://doi.org/10.1016/j.tjnut.2024.10.012.
DOI: https://doi.org/10.1016/j.tjnut.2024.10.012

Interpretive Summary: Carotenoids are biologically active components, called phytochemicals, found primarily in fruits and vegetables. Consuming a carotenoid-rich diet is associated with a reduced risk of chronic diseases including cancers, notably prostate cancer, cardiovascular disease, cognitive decline, and macular degeneration. There are different specific carotenoids found in foods, some carotenoids seem to be better absorbed and accumulated in body tissues than others. However, the specific reasons for that finding are unclear. This study quantified the degree to which 3 major tomato carotenoids, lycopene, phytoene, and beta-carotene, are absorbed by intestinal cells, are stable in serum, are taken up by prostate cancer and non-cancer cells, and and disappear from prostate cells. All three carotenoids were taken up by and cleared from prostate cells at a similar rate, while the intestinal cells absorbed the greatest portion of phytoene, followed by beta-carotene and lycopene. Phytoene was also the most stable carotenoid. The greater stability of phytoene and intestinal uptake of phytoene may provide an explanation as to why phytoene, despite being less abundant in tomato foods than lycopene, is accumulated to a greater degree in human prostate tissue. This study generally highlights the importance of bioavailability and phytochemical stability in dictating tissue biodistribution and accumulation.

Technical Abstract: The purpose of this study was to determine if differences in stability, cellular uptake, and clearance of phytoene compared with lycopene or ß-carotene by prostate and intestinal cells may explain differences in observed tissue carotenoid profiles. Gene and protein expression for carotenoid metabolism in prostate cell lines were analyzed by qRT-PCR and Western blot, respectively. Uptake, efflux, and clearance of phytoene, lycopene, or B-carotene by prostate cell [LNCaP (Lymph Node Carcinoma of the Prostate cell line), RWPE-1 (a human prostate epithelial cell line), and PC-3 (a prostate cancer cell line)] and absorptive enterocyte (Caco-2) cultures were compared. The effect of scavenger receptor class B member 1 (SCARB1) inhibition on carotenoid uptake by LNCaP, RWPE-1, and Caco-2 cells was tested. SCARB1 was expressed across prostate cell lines. Lycopene, phytoene, and ß-carotene uptakes were similar in LNCaP and PC-3 cells, whereas RWPE-1 cells absorbed a smaller portion of the phytoene dose than lycopene or ß-carotene doses. The clearance rates of carotenoids from LNCaP cells did not differ. Intestinal cell uptake of phytoene was greatest, followed by B-carotene and lycopene. SCARBI inhibitor treatment did not significantly reduce the uptake or efflux of carotenoids by LNCaP or Caco-2 cells at the dose concentration provided. Overall, this study suggests that greater bioavailability at the point of the intestine and greater stability of phytoene are determinants of the relative enrichment of phytoene in prostate tissue.