微管-微丝系统的改变对培养的MGc 80-3人胃癌细胞粘液分泌的影响

EFFECT OF THE CHANGES IN MICROTUBULAR-MICROFILAMENTOUS SYSTEM ON THE MUCUS SECRETION OF CULTURED MGc80-3 HUMAN STOMACH CANCER CELLS

本工作用PAS反应显示粘液蛋白的方法对细胞内微管微丝变化时人胃腺癌MGc 80-3细胞粘液分泌活动进行了研究。秋水仙酰胺、低温(2~4℃)及细胞松弛素B(CB)处理后,细胞内微管微丝解聚,粘液分泌活动受到抑制,当细胞从低温回置37℃温育,微管重新组装后,粘液分泌又得到恢复。Taxol短时间处理对MGc 80-3细胞粘液分泌有促进作用、但长时间处理后,由于细胞内微管的高度浓集化,从而破坏了细胞内微管网络结构(CMTC),使粘液分泌活动停止,说明人胃腺癌MGc80-3细胞的粘液分泌活动依赖于细胞内CMTC和微丝的存在。毛果芸香碱能直接刺激培养的MGc 80-3细胞的粘液分泌,提示人胃腺癌MGc 80-3细胞膜也可能存在类胆碱能受体。硫杂脯氨酸对人胃腺癌MGc 80-3细胞的增殖具有抑制作用,但对其粘液分泌具有强烈的刺激作用,这种刺激作用可通过加速粘液的排放而实现。毛果芸香碱和硫杂脯氨酸对MGc 80-3细胞粘液分泌的刺激作用也依赖于细胞内微管微丝的存在,一旦微管微丝解聚,其刺激粘液分泌的作用便消失。db-cAMP对MGc 80-3细胞的粘液分泌也有促进作用。CB单独处理或CB与秋水仙酰胺同时处理,都能抑制MGc 80-3细胞的粘液分泌,但CB单独处理后,分泌颗粒多聚集于细胞边缘,而CB与秋水仙酰胺同时处理后,分泌颗粒则散在分布于胞质中,提示在MGc 80-3细胞内微丝对粘液的排放,而微管对分泌颗粒的输送起主要作用。

MGc80-3 human stomach cancer cell line,which secreted mucus,was used to study the effect of the changes in microtubular-microfilamentous system on cell secretion.The mucus was identified by PAS staining method.We have found that the mucus secretion was inhibited in cultured MGc80-3 cells after treatment with 0.1μg/ml colcemid for 4 hrs or with cold(2-4℃)for 2 hrs.The mucus secretion of these cells was recovered after remove from cold.to 37°C for 6 hrs.Taxol can stabilize labile microtubule.We also found that the mucus secretion was enhanced in these cells after treatment.with 10^(-5)M taxol for 2 hrs.However,the mucus secretion was evidently inhibited after treating the cells'with 10^(-5)M taxol for 24 hrs.Taxol can counteract on the depolymerization of microtubules by the colcemid treatment.The resuls of our experiment show that the mucus secretion of these cells was not influenced if they were treated with 10^(-5)M taxol and 0.1μg/ml colcemid for 2 hrs.either simultaneously or in accession.The secretory activity of these cells was evidently inhibited after treatment with 4μg/ml cytochalasin B for 6 hrs.Our results indicate that the mucus secretion of MGc80-3 human stomach cancer cells closely depended on the presence of both microtubules and microfilaments.We also found that the mucus secretion of MGc80-3 cells was enhanced by treatment with lμg/ml pilocarpine for 6 hrs.The proliferation of MGc80-3 cell population was inhibited by thiazolidine-4 carboxylic acid.However,the secretory activity of these cells was evidently enhanced after treatment with 0.1μg/ml thiazolidine-4 carboxylic acid for 10 hrs.The stimulating effect of pilocarpine and thiazolidine-4 carboxylic acid disappeared after the microtubules and microfilaments were disassembled by treatment with colcemid and cytochalasin B.In addition,our experiments also show that the mucus secretion of these cells was increased after treatment with ImM db-cAMP.These findings convincingly support the assumption that motile events placed under the control of the microtubular-microfilamentous system are intimately involved in the mucus secretion of MGc80-3 human stomach cancer cells.