Relative Uptake of Tomato Carotenoids by In Vitro Intestinal and Prostate Cancer Cells

Area of Science:

• Nutritional biochemistry
• Cancer research
• Molecular biology

Background:

• Tomato consumption and carotenoids are linked to reduced prostate cancer risk.
• Prostate tissue accumulates lycopene, beta-carotene, and phytoene.
• Phytoene is relatively more abundant in prostate tissue than lycopene, but the reasons are unclear.

Purpose of the Study:

• To investigate if differences in phytoene stability, cellular uptake, and clearance compared to lycopene and beta-carotene explain prostate tissue carotenoid profiles.
• To compare carotenoid handling by prostate and intestinal cells.

Main Methods:

• Analyzed carotenoid metabolism gene/protein expression in prostate cell lines (LNCaP, RWPE-1, PC-3).
• Compared uptake, efflux, and clearance of phytoene, lycopene, and beta-carotene in prostate and Caco-2 intestinal cells.
• Assessed the impact of scavenger receptor class B member 1 (SCARB1) inhibition on carotenoid uptake.

Main Results:

• SCARB1 was expressed in prostate cells. Phytoene, lycopene, and beta-carotene uptake varied between prostate cell lines.
• Intestinal Caco-2 cells showed the highest uptake of phytoene, followed by beta-carotene and lycopene.
• SCARB1 inhibition did not significantly alter carotenoid uptake or efflux in tested cells.

Conclusions:

• Greater bioavailability in the intestine and enhanced stability contribute to phytoene's enrichment in prostate tissue.
• These factors likely explain the observed differences in tissue carotenoid profiles.