Anti-proliferative and anti-inflammatory activities of tomato lipophilic extracts

Dietary intake of tomatoes or tomato products has been shown to protect against a broad range of cancers and cardiovascular diseases by reducing the susceptibility of low density lipoprotein (LDL) to oxidative damage. The susceptibility of LDL to oxidative modifications is decreased by acyl-PAF, an acyl analogue of platelet-activating factor (PAF), a potent inflammatory mediator. The biosynthesis of PAF and acyl-PAF is catalysed by the acetyl-CoA acetyltransferase (AT) in the last step of the remodelling route. The PAF-dependent transacetylase (TA) contributes to the acyl-PAF biosynthesis. This enzyme shows three different catalytic activities. It can transfer the acetyl group from PAF to lysophospholipids (TAL activity), contributing to acyl-PAF biosynthesis; or it can transfer the acetyl group from PAF to sphingosine (TAS activity); or it can act as an acetylhydrolase by transforming PAF into lyso-PAF (AH activity). In the present study we investigated the anti-proliferative and anti-inflammatory activities of tomato lipophilic extracts rich in lycopene, namely HLY13, HLY14, AU Fresh 900, and San Marzano in Kaposi's sarcoma (KS) cells. The results indicate that tomato lipophilic extract (SM) modulates the PAF and acyl-PAF metabolism in VEGF-stimulated KS cells by inhibiting the AT activity and by enhancing the TAL activity. Tomato lipophilic extracts, HLY13, HLY14, All Fresh 900, and San Marzano all significantly reduced the VEGF-induced KS cell proliferation. In particular, results indicate that San Marzano extract (SM) is more active in inhibiting the VEGF-induced KS cell proliferation and that its effect is potentiated by the addition of α-tocopherol.