Hwang Eun-Sun, Bowen Phyllis E
Center for Agricultural Biomaterial, Seoul National University, San 56-1, Shillim-dong, Kwanak-gu, Seoul 151-742, Korea.
Biofactors. 2005;23(2):97-105. doi: 10.1002/biof.5520230205.
Animal and epidemiological studies point to a cancer preventive/therapeutic role for tomato products and its antioxidant, lycopene. It is hypothesized that lycopene will behave as an antioxidant at low concentrations and as a prooxidant at high concentrations in LNCaP human prostate cancer cell culture systems. We characterized the antioxidant, and prooxidant effects of a hexane extract of tomato paste (TP) and water solubilized lycopene at different concentrations using a prostate cancer cell line. Placebo (5% triglyceride, Roche Inc.) was used as a control. After 6, 24 hr and 48 hr incubation, LNCaP cells were harvested and used for each measurement. Cellular proliferation was determined using the MTT colorimetric assay. Lycopene and TP hexane extract inhibited cell growth in a dose-dependent (0.1-50 microM lycopene) manner and growth inhibition was 55% and 35% at 1 microM lycopene and TP hexane extract, respectively after 48 hr incubation. The levels of 8-hydroxydeoxyguanosine/deoxyguanosine (an oxidative DNA damage product) was significantly increased starting at 5 microM lycopene from both TP hexane extract and pure lycopene after 24 and 48 hr incubation with no protection at the lower concentrations. Malondialdehyde formation (a lipid peroxidation product measured by HPLC separation of the MDA-TBA adduct) was significantly reduced at low concentrations (0.1-1 microM) of lycopene in all treatments. Clinically relevant concentrations of lycopene and the tomato fraction containing lycopene significantly reduced LNCaP cancer cell survival which can only be partially explained by increased DNA damage at high lycopene concentrations (> 5 microM). Low concentrations of lycopene acted as a lipid antioxidant but did not protect DNA.
动物和流行病学研究表明，番茄制品及其抗氧化剂番茄红素具有防癌/抗癌作用。据推测，在LNCaP人前列腺癌细胞培养系统中，番茄红素在低浓度时表现为抗氧化剂，在高浓度时表现为促氧化剂。我们使用前列腺癌细胞系，对不同浓度的番茄酱己烷提取物（TP）和水溶性番茄红素的抗氧化和促氧化作用进行了表征。使用安慰剂（5%甘油三酯，罗氏公司）作为对照。孵育6、24小时和48小时后，收获LNCaP细胞并用于各项测量。使用MTT比色法测定细胞增殖。番茄红素和TP己烷提取物以剂量依赖性（0.1 - 50 microM番茄红素）方式抑制细胞生长，孵育48小时后，在1 microM番茄红素和TP己烷提取物时，生长抑制率分别为55%和35%。在与TP己烷提取物和纯番茄红素孵育24小时和48小时后，从5 microM番茄红素开始，8 - 羟基脱氧鸟苷/脱氧鸟苷（一种氧化性DNA损伤产物）的水平显著增加，在较低浓度下没有保护作用。在所有处理中，低浓度（0.1 - 1 microM）的番茄红素显著降低了丙二醛的形成（通过HPLC分离MDA - TBA加合物测量的脂质过氧化产物）。临床相关浓度的番茄红素和含有番茄红素的番茄组分显著降低了LNCaP癌细胞的存活率，这只能部分地由高番茄红素浓度（> 5 microM）下DNA损伤增加来解释。低浓度的番茄红素作为脂质抗氧化剂，但不能保护DNA。
