金黄葡萄球菌肠毒素C2对小鼠移植瘤的抑制作用

Inhibitory effect of staphylococcal enterotoxin C2 on xenograft tumors in mice

目的采用小鼠移植瘤模型,对金黄葡萄球菌肠毒素C2的抗肿瘤作用进行研究,以进一步揭示超抗原在肿瘤治疗方面的意义。方法从金葡菌发酵液中提纯SEC2蛋白,并经SDS-PAGE及测序分析;构建小鼠S180肉瘤和Lewis肺癌移植瘤模型,分别腹腔注射高、中、低剂量(800、400、200 ng/kg)的SEC2,连续给药10 d,同时以环磷酰胺为阳性对照,生理盐水为阴性对照。于给药后第11天处死小鼠,将肿瘤组织分离并称重,比较SEC2对S180肉瘤及Lewis肺癌移植瘤的抑瘤效果。结果在相对分子质量约30 000处可见目的条带,与理论值相符,N-未端氨基酸测序与文献报道一致;SEC2对两种移植瘤均产生较明显抑制作用,高、中、低剂量SEC2对S180肉瘤的抑瘤率分别达到50.60%、31.81%和19.38%,对Lewis肺癌的抑瘤率分别达到55.62%、45.70%和37.78%。结论从动物水平上确认了SEC2的抑瘤效果,为进一步开展超抗原抗肿瘤研究奠定了基础。

Objective To investigate the anti-tumor effect of staphylococcal enterotoxin C2（SEC2）using mouse model of xenograft and further understand the role of superantigens in tumor therapy.Methods SEC2 protein was extracted from whole cell Staphylococcus aureus and identified by SDS-PAGE and sequencing.Mouse models of xenograft S180 sarcoma and Lewis lung cancer were established.The model mice were injected i.p.with SEC2 at high（800 ng / kg）,moderate（400 ng / kg）and low（200 ng / kg） dosages respectively for 10 d starting from day 1 after inoculation of xengraft tumor cells,using cyclophosphamide as positive control and physiological saline as negative control.The mice were killed on day 11 after injection,of which the tumor tissues were isolated and weighed to compare the inhibitory effect of SEC2 on xenograft S180 sarcoma and Lewis lung cancer were compared.Results The target band with a relative molecular mass of about 30 000 was observed,which was identical to that in theory.The amino acid sequence at N-terminus of the target band was consistent with that reported in documents.SEC2 showed significantly inhibitory effect on both the xenograft tumors,of which the inhibitory rates at high,moderate and low dosages were 50.60%,31.81% and 19.38% to S180 sarcoma,and 55.62%,45.70% and 37.78% to Lewis lung cancer,respectively.Conclusion The inhibitory effect of SEC2 on tumors was confirmed in animal models,which laid a foundation of further study on anti-tumor effect of superantigens.