The exopolysaccharide (EPS) of some Lactobacillus strains has been reported to exert anti-cancer activities. In this study, the effects of crude EPSs produced by four Lactobacillus plantarum strains (Lactobacillus plantarum-12, L. plantarum-14, L. plantarum-32, and L. plantarum-37) on HT-29 cell proliferation and apoptosis were studied. The results showed that the inhibition rate of the crude EPS produced by L. plantarum-12 on HT-29 cell proliferation was significantly higher than that of the EPS produced by the other three strains. L. plantarum-12 crude EPS (50, 100, 250, 500 μg/ml) exerted inhibitory effects on the expression of proliferating cell nuclear antigen (PCNA) in HT-29 cells in a positive dose-dependent manner. The reactive oxygen species (ROS) level and apoptosis rate were also increased in HT-29 cells treated with different concentrations of L. plantarum-12 crude EPS compared with control cells. Further studies found that the expression of the pro-apoptotic proteins Bax, Cyt C, caspase-3, caspase-8 and caspase-9 was upregulated and that the expression of the anti-apoptosis protein Bcl-2 was decreased in HT-29 cells treated with L. plantarum-12 crude EPS compared with control cells. The results suggested that the EPS produced by L. plantarum-12 could inhibit the proliferation of the human colon cancer cell line HT-29 through the mitochondrial pathway.

据报道，一些乳杆菌菌株的胞外多糖 (EPS)具有抗癌活性。在本研究中，研究了四种植物乳杆菌菌株（植物乳杆菌-12、植物乳杆菌-14、植物乳杆菌-32 和植物乳杆菌-37）产生的粗 EPSs对 HT-29 细胞增殖和凋亡的影响. 结果表明，植物乳杆菌-12生产的粗EPS对HT-29细胞增殖的抑制率明显高于其他3株生产的EPS。植物乳杆菌-12粗EPS(50, 100, 250, 500 μg/ml)对HT-29细胞增殖细胞核抗原(PCNA)表达呈阳性剂量依赖性抑制作用。与对照细胞相比，用不同浓度的植物乳杆菌-12 粗 EPS处理的 HT-29 细胞中的活性氧 (ROS) 水平和细胞凋亡率也增加。进一步研究发现，HT-29细胞中促凋亡蛋白Bax、Cyt C、caspase-3、caspase-8和caspase-9的表达上调，抗凋亡蛋白Bcl-2的表达降低与对照细胞相比，用植物乳杆菌-12 粗 EPS处理。结果表明，植物乳杆菌产生的 EPS-12可以通过线粒体途径抑制人结肠癌细胞株HT-29的增殖。