转移相关1基因对胃癌细胞生物学行为的影响

Effects of MTA1 on biological behaviors of gastric cancer cells

目的研究肿瘤转移相关1（MTA1）基因对胃癌细胞迁移、侵袭、生长等多种生物学特性的影响。方法利用pSilencer3.1－MTA1－siRNA载体构建稳定敲降MTA1的人胃癌BGC－823细胞，通过Boyden实验、划痕愈合实验、克隆形成实验和四甲基偶氮唑蓝（MTT）法检测敲降MTA1基因对BGC－823细胞多种生物学行为的影响。同时，利用pcDNA3－MTA1质粒过表达MTA1基因进行反向验证。在裸鼠皮下分别注射pSilencer3.1－MTA1－siRNA转染细胞、pcDNA3－MTA1转染细胞和对照细胞，检测MTA1基因对胃癌BGC823细胞体内成瘤能力的影响。采用逆转录聚合酶链反应（RT－PCR）测定pSilencer3.1－MTA1－siRNA转染组、pcDNA3－MTA1转染组和对照组细胞中integrinβ1、cyclinD1和尿激酶受体（uPAR）等转移相关基因的表达，观察其与MTA1表达的相关性。结果成功构建了稳定敲降及过表达MTA1的BGC－823细胞。Boyden实验和划痕愈合实验结果显示，与对照组细胞比较，pSilencer3.1－MTA1－siRNA转染组发生迁移和侵袭的细胞数明显减少[分别为（25±2）和（12±1）个]，pcDNA3－MTA1转染组发生迁移和侵袭的细胞数则明显增多[分别为（218±2）和（269±3）个]，差异均有统计学意义（均P〈0.01）。MTT法和克隆形成实验结果表明，pcDNA3－MTA1转染组细胞生长加快，克隆形成能力增强，pSilencer3.1－MTA1－siRNA转染组细胞与之相反。皮下成瘤实验显示，pSilencer3.1－MTA1－siRNA转染组肿瘤体积和重量分别为（711.32±284.30）mm3和（0.87±0.24）g，明显小于对照组[（1 482.41±511.90）mm3和（1.39±0.30）g]，而pcDNA3－MTA1转染组肿瘤体积和肿瘤重量分别为（3 158.73±1 823.22）mm3和（2.23±0.51）g，明显大于对照组，差异均有统计学意义（均P〈0.05）。RT－PCR检测结果显示，与对照组细胞比较，pSilencer3.1－MTA1－siRNA转染组细胞cyclinD1、integrinβ1和uPAR mRNA表达下调，而pcDNA3－MTA1转染组细胞cyclinD1、integrinβ1和uPAR mRNA表达上调。结论敲降MTA1可削弱人胃癌BGC－823细胞的增殖、侵袭及迁移能力，而MTA1的过表达不仅能够增强BGC－823细胞的上述能力，还明显促进BGC－823细胞的体内成瘤能力，并诱发恶性胃癌表型。MTA1可能通过调控其他转移相关基因进而调控肿瘤细胞的多种生物学行为。

ObjectiveTo study the effects of metastasis associated 1 （MTA1） on biological characteristics such as migration, invasion and proliferation of gastric cancer （GC） cells.MethodspSilencer3.1-MTA1-siRNA vector was used to establish human gastric cancer BGC-823 cell lines with constitutive MTA1-knockdown. Boyden, wound healing, clony forming assay and 3-（4, 5-dimethyl-2-thiazolyl）-2, 5-diphenyl-2H tetrazolium bromide （MTT） assay were performed to identify the effects of MTA1-deficiency on the biological behaviors of BGC-823 cells in vitro. Simultaneously, MTA1 overexpressed BGC-823 cell line was established by pcDNA3-MTA1 plasmid transfection for reverse verification. In addition, the role of MTA1 in the tumorigenicity of gastric cancer BGC823 cells in vivo was examined by subcutaneous injection of BGC-823 cells expressing different MTA1 levels into nude mice. Reverse transcription-polymerase chain reaction （RT-PCR） and western blot were used to detect the expression levels of integrin β1, cyclin D1 and uPAR in pSilencer3.1-MTA1-siRNA, pcDNA3-MTA1 transfected cells and control cells.ResultsMTA1 knocked down or upregulated BGC-823 cell lines were successfully generated by transfecting pSilencer3.1-MTA1-siRNA or pcDNA3-MTA1 vector with lipofectamine 2000, respectively. The Boyden and wound healing experiments showed metastasis and invasion ability in MTA1 knocked down cells （25±2, 12±1） were significantly decreased when compared with those of control （78±2, 50±2） and MTA1-overexpressed groups （218±2, 269±3; P〈0.05）. The results of MTT assay and colony forming assay were significantly decreased when compared with those of showed that MTA1 overexpressed cells grew more rapidly and formed more colonies in vitro and induced worse malignant tumors in vivo, while MTA1 knocked down cells presented the reversed phenotype[control group （1 482.41±511.90） mm3, （1.39±0.29）g; MTA1 overexpressed group [（3 158.73±1 823.22） mm3, （2.23±0.51）g; MTA1-downregulated group （711.32±284.30）mm3, （0.87±0.21） g ; P〈0.05）]. In addition, RT-PCR result showed that the expression level of MTA1 was positively correlated with the known metastasis-related genes （integrinβ1, cyclinD1, uPAR）.ConclusionsMTA1 promotes the invasion, migration and proliferation of human gastric cancer BGC-823 cells. On the contrary, down-regulation of MTA1 significantly inhibits tumorigenicity of BGC-823 cells and induces favorable phenotypes. MTA1 may promote the malignant phenotype of BGC-23 cells via regulating the expressions of integrinβ1, cyclinD1 and uPAR.