双歧杆菌LTA上调ICAM-1表达及其在LAK抗肿瘤中的作用

Upregulation of ICAM-1 expression enhances cytotoxic sensitivity of tumor cells to LAK by LTA from bifidobacterium

目的探讨双歧杆菌脂磷壁酸( lipoteichoic acid,LTA)作用于LoVo细胞后是否能增强LAK 对该细胞的识别和杀伤, 以及ICAM-1在其中的作用。方法采用MTT方 法观察了L AK对LoVo细胞的识别和杀伤作用,并用流式细胞仪和ELISA的方法检测了LoV o细胞表面ICAM-1的表达。结果50μg/ ml LTA作用3 d,LAK对LoVo细胞的粘附率由9.62%增加到24.42 % ,LoVo细胞对LAK的杀伤敏感性增加了2倍。并且使表达ICAM-1的细胞数由2 .42%增加到27.9%,LoVo细胞上ICAM-1的表达量增加10倍。结论LTA增强了LoV o细胞对LAK的杀伤敏感性,其机制可能在于LTA通过上调LoVo细胞上ICA M-1的表达,增强了效靶细胞之间的识别和结合。LTA与LAK相结合可能增强对大肠 癌的治疗效果。

Objective To investigate whet her the recognizing and cytotoxic abilities of LAK can be intensified by bifidob acterial lipoteichoic acid(LTA) and the possible role of ICAM-1 in this process. MethodsStandard MTT assay was used to evaluate the binding rate and cytotoxic capability of LAK to LoVo cells.Flow cytometric assay and ELISA were used to determine the expression of ICAM-1 on these cells.ResultsLAK cells bound much easier to LoVo cells with an increase from 9 .62% to 24.42% as well as a double increase of the anti-tumor sensitivity of Lo Vo cells to LAK after challenge with 50 μ g/ml LTA of Bifidobacterium bifidum 110 1.Compared with the control group,both the percentage of ICAM-1 positive cells and the amount of ICAM-1 expression on Lo Vo cells were greatly increased directly after the challenge of LTA.Conclusi onThe possible mechanism of the increase of a ntitumor activity lies in that Bifidobac terial LTA can intensify the binding and recognizing capability of LAK to tumor cells by promoting the expression of ICA M-1 on the surface of Lo Vo cells.The th erapeutic effect on intestinal cancer ma y be enhanced by the combined treatment of bifidobacterial LTA and LAK.