PTEN/PI3K突变对肺癌细胞基因表达谱的影响

Effect of PTEN/PI3K mutations on gene expression profiling of lung cancer cells

目的:探讨第10号染色体同源丢失性磷酸酶-张力蛋白(phosphatase and tensin homolog deleted on chromosome ten,PTEN)和磷脂酰肌醇-3激酶(phosphoinositide3-kinase,PI3K)基因突变对肺癌细胞基因表达谱的影响。方法:采用蛋白质印迹法检测19株非小细胞肺癌细胞中PTEN表达情况,测序验证PTEN基因是否发生突变,检测该突变对于PTEN下游分子AKT和mTOR通路产生的影响。利用基因集富集分析(gene set enrichment analysis,GSEA)方法对19株肺癌细胞的基因表达谱数据进行PTEN/PI3K突变的功能分析。结果:19株非小细胞肺癌细胞中有5株PTEN蛋白表达缺失,通过测序发现这5株均存在PTEN突变;文献检索另有2株存在PIK3CA突变。PTEN突变后其下游分子AKT和mTOR通路处于持续活化状态。借助GSEA法对肺癌细胞基因表达谱数据进行分析,发现PTEN(或PI3K)突变对肺癌细胞的线粒体-能量代谢的基因集产生了重要影响。结论:PTEN/PI3K突变对其下游分子AKT和mTOR通路产生明显影响,对肺癌细胞基因表达谱的影响主要体现在线粒体-能量代谢方面的基因集。这一发现提示,有必要重视线粒体-能量代谢在肺癌发生中的作用。

Objective： To investigate the effect of PTEN （phosphatase and tensin homolog deleted on chromosome ten）/PI3K （phosphoinositide 3-kinase） mutation on gene expression profiling of lung cancer cell lines. Methods： PTEN protein expression levels were analyzed by Western blotting, and the PTEN gene mutation was confirmed by sequencing in 19 NSCLC （non-small cell lung cancer） cell lines. The effect of PTEN gene mutation on the downstream AKT and mTOR pathways was also examined by Western blotting. GSEA （Gene set enrichment analysis） was employed to investigate the difference of gene expression profiling induced by PTEN/PI3K mutation in 19 NSCLC cell lines. Results： In this study, 19 NSCLC cell lines had been screened, and 5 cell lines had no PTEN protein expression and harbored PTEN mutation. Other 2 cell lines had PIK3CA mutation, which was found by database retrieval. The mutation of PTEN gene had a significant impact on the continuous activation of its downstream molecules AKT and mTOR pathways. GSEA was used to compare the gene expression profiling characters between the CON （without PTEN or PIK3CA mutation） and the MUT （with PTEN or PIK3CA mutation） groups of NSCLC cell lines. It was surprising that the most enriched gene set affected by PTEN/PI3K dysfunction was the mitochondrial-metabolism gene set. Conclusion： Mutation of PTEN/PI3K may affect its downstream molecules AKT and mTOR pathways as well as the lung cancer cells＇ gene expression profiling, especially for the mitochondrial-metabolism gene set. This finding implies the importance of mitochondrial-metabolism regulation in lung cancer development.