骨骼肌源性抑瘤物的体外初步研究

Preliminary study on skeletal muscle derived tumor suppressor

目的 观察骨骼肌细胞条件培养液 (MCM)体外对肿瘤细胞增殖的影响 ,并初步分析骨骼肌源性抑瘤物的理化特性及抑瘤机理。 方法 用噻唑蓝分析法 (MTT法 )分析新生大鼠MCM对不同肿瘤细胞系的体外抑瘤作用。用超滤分离、热灭活处理、胰酶消化、凋亡分析及形态学观察分析骨骼肌源性抑瘤物的理化特性及抑瘤机理。 结果 MCM与哺乳动物源性肿瘤细胞 (小鼠骨髓瘤SP2 / 0及Wistar大鼠癌肉瘤Walker2 5 6 )、人源性白血病细胞 (人慢性粒细胞白血病K5 6 2及人急性淋巴细胞白血病HL6 0 )、实体瘤细胞 (人结肠腺癌细胞LS 174 T及人前列腺癌细胞PC3 M) ,以及不同转移潜能肺癌细胞 (人肺癌低转移株PLA80 1 C及人肺癌高转移株PLA80 1 D)共同培养后 ,肿瘤细胞的增殖显著下降 (P <0 0 1～ 0 0 5 ) ,且肿瘤细胞增殖呈不同程度MCM浓度依赖性。MCM与正常细胞 (兔关节骺板细胞RGP 2 )共同培养后 ,细胞增殖无下降。同一来源肺癌细胞 ,在MCM稀释至原液的 6 2 5 %时 ,仍见高转移株增殖显著受抑 (P <0 0 1～ 0 0 5 ) ,而在MCM稀释至原液的 2 5 %时 ,低转移株增殖即无显著受抑。MCM的抑瘤活性存在于分子量 10 0 0 0以下超滤组分 ,热灭活后活性消失 ,胰蛋白酶消化后活性仍存在。MCM不引起K5 6 2细胞凋亡 ,而导致肿瘤细胞膜变?

Objective To investigate the effect of new born rat skeletal muscle conditioned medium(MCM) on proliferation of tumor cells, and its physicochemical characteristics and mechanisms of action. Methods The effects of MCM were tested on a variety of cells by MTT assay. MCM was also tested following ultrafiltration,boiling at 100℃ and treatment with trypsin. Morphology and apoptosis of the MCM-treated cells were examined. Results Proliferation of mouse myeloma SP2/0, rat carcino-sarcoma Walker*!256, and tumor cell lines of human origin, including leukemia K562 and HL-60, colon adenocarcinoma LS-174-T, prostatic carcinoma PC3-M, and lung adenocarcinoma with low(PLA801-C) and high(PLA801-D) metastatic potential were significantly decreased when cultured with MCM(P<0.01～0.05) in a dose-dependent manner. The proliferation of normal cells(RGP-2 rabbit joint epiphysial disk cells)was not affected by MCM. Proliferation of the lung adenocarcinoma with high metastatic potential was more susceptible to the growth inhibitory effect of MCM as compared to that with low metastatic potential. On ultrafiltration, the inhibitory activity of MCM existed in the fraction with a molecular weight≤10*!000. It was trypsin resistant but thermolabile. Apoptosis was not seen but the cytoplasmic membrane of tumor cells was destroyed after cultured in MCM. Conclusion Rat skeletal muscle cells produce low molecular weight tumor suppressor(s) capable of selectively inhibiting tumor cell proliferation in vitro. Its activity is neither species- nor tumor-specific. The skeletal muscle derived tumor suppressor(s) may play a key role in the rarity of tumor metastases in skeletal muscles.