摘要:
环境污染物增加癌症死亡率的潜在机理研究尚需开展。选择与癌症致死显著相关的林丹作为目标物质,将黑腹果蝇作为受试生物进行暴露,对1 000 μg·L-1和对照组的果蝇样本进行实时聚合酶链式反应(RT-PCR),检测发现参与调控癌症细胞迁移的丝裂原活化蛋白激酶(MAPK)信号通路中的MEKK和p38α、未折叠蛋白反应(UPR)中的ATF4、Ire1、PERK和XBP1等基因的表达量呈现显著下调(P<0.05)。通过肿瘤迁移品系果蝇统计林丹暴露下肿瘤细胞迁移率,结果显示肿瘤细胞迁移率随林丹浓度升高而增加,1 000 μg·L-1林丹暴露组与对照组的果蝇肿瘤细胞迁移率分别为69.2%和45.9%,具有显著性差异(P<0.05)。进一步的RNA测序结果表明,高浓度暴露组与对照组之间存在380个基因具有显著性差异(P<0.05),其中含169个上调基因和211个下调基因。差异基因主要涉及水解酶催化活性(42个基因)、神经系统(20)、对化学刺激的感知(6)和线粒体(5)。差异基因的富集分析表明林丹的暴露主要改变蛋白水解过程(83个基因)、胞外区域(84)和催化活性(311),其对应的平均富集因子分别为1.59、1.52和1.24(P<0.001)。差异基因的表达解释了林丹的暴露不仅致使线粒体功能障碍,而且影响蛋白水解酶活性,加速胞外基质降解,为肿瘤细胞迁移供能并提供微环境。
Abstract:
It remained wide open on the mechanisms underlying the connection between pollutant exposure and cancer mortality. The target chemical in the present study was lindane whose exposure correlated with cancer mortality. Drosophila melanogaster were exposed to different concentrations of lindane. RT-PCR were carried out on the samples which were exposed to 1 000 μg·L-1 lindane and the control, to measure the expression of target genes in MAPK and UPR pathways. A visible Drosophila stain was used to calculate the tumor cell migration rate. Then, the potential mechanism was explored through RNA sequencing. The RT-PCR results showed that tumor migration-related genes in pathways of mitogen-activated protein kinases (MAPK) (e.g., MEKK and p38α) and unfolded protein response (UPR) (e.g., ATF4, Ire1, PERK and XBP1) were down-regulated significantly (P<0.05). Results of tumor cell migration rate showed that lindane enhanced the tumor cell migration compared with the control. The tumor cell migration rates at 1 000 μg·L-1 and the control were 69.2% and 45.9%, respectively (P<0.05), showing a concentration-dependence. Furtherly, the RNA-sequencing results showed that 380 genes had significant differences (P<0.05), containing 169 up-regulated and 211 down-regulated genes. These genes mainly involved in catalytic activity of hydrolase (42 genes) and biological processes of neurological system (20), sensory perception of chemical stimulus (6) and mitochondrion (5). Differential gene enrichment analysis declared that most involved genes were in the processes of proteolysis (83), extracellular region (84) and catalytic activity (311) with the mean enrichment factor of 1.59, 1.52, 1.24, respectively (P<0.001). The expression of differential genes mainly involved mitochondrial dysfunction and proteinase activity for degrading extracellular matrix, the activities of which provides energy for the observed tumor cell migration.
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