| OBJECTIVE: We study the relationship between PTEN and AURKA in gastric cancer,and explore the mechanism of the low expression of PTEN mediated by AURKA activation maintain the malignant phenotype in human gastric adenocarcinoma.METHODS:We collected the clinical data from the TCGA database,and analyzed the phosphatase and tensin homolog deleted on chromosome 10(PTEN)and aurora kinase A(AURKA)gene alterations by using the c Bio Portal for Cancer Genomics.We next examined expression levels of PTEN and AURKA through RT-q PCR,western blot and immunocytochemical analyses in gastric carcinoma and normal mucosa samples.Meanwhile,we transfected MGC-803 and SGC-7901 cells with PTEN si RNA or AURKA si RNA,and monitored them for proliferation and invasion by CCK-8 and Transwell.Besides,to explore whether PTEN and AURKA gene expression could predict gastric cancer patient survival,we analyzed the PTEN and AURKA gene expression in gastric cancer patients using KM Plotter.We analyzed the connection between PTEN and AURKA by using c Bio Portal,to further study the interaction mechanism of PTEN and AURKA,we analyzed the gene and protein expression of PTEN and AURKA in MGC-803 and SGC-7901 cells after transfection by si-PTEN and si-AURKA.Moreover,we found that the expression level of P-AURKA is also affected by the above gene expression level.Based on these observations,we hypothesized that P-AURKA is a downstream target of PTEN.To test this hypothesis,we employed a double variable experiment to analyze the effect of PTEN on P-AURKA expression and thus the activity of AURKA.Finally,Suppression of PTEN affected many signal pathways involved in the development of gastric cancer.RESULTS:This study reveals that PTEN(amplifications,deep deletions,truncating mutations and missense mutations)and AURKA(amplifications,and missense mutations)gene alterations.When compared with the high frequency of AURKA genetic deletions,PTEN deletions accounted for most alterations.Real-time RT-PCR,Western blot and immunocytochemistry showed that the expression of AURKA in gastric carcinoma was higher than in normal gastric mucosa,while the expression of PTEN in the normal gastric mucosa was higher than that in gastric carcinoma.Compared with control vector-transfected cells,transient transfection of si-PTEN led to a marked increase in proliferation and invasion in both gastric cancer cell lines,while AURKA knockdown resulted in decrease proliferation and invasion compared to the untreated group.KM Plotter analyses reveals that patients with high expression of PTEN were predicted to have better overall survival,and the median survival time of the PTEN high-expressing group was 123.6 months.However,gastric cancer patients with high expression of AURKA had overall poor survival when compared with patients with low expression of AURKA.The c Bio Portal analyses reveals that the expressions of PTEN was significantly negatively correlated to AURKA expression.Down-regulation of PTEN by si RNA not only increased the expression of AURKA at both m RNA and protein levels,but also increased the expression of P-AURKA.In addition,we found that down-regulation of AURKA could also affect the expression level of PTEN.Furthermore,PTEN could suppress the malignant phenotype changes of gastric adenocarcinoma cells by regulating the expression of AURKA inhibited by P-AURKA.Moreover,PTEN resulted in increased expression of some target,intracellular signaling pathway-related molecules to promote the development of gastric cancer.CONCLUTION:Our study confirmed that P-AURKA plays an important role in the development of gastric adenocarcinoma and revealed a novel functional link between PTEN,AURKA and P-AURKA activation.This study also provides a novel drug design strategy in targeting both PTEN and AURKA for more specific killing of gastric cancer cells while sparing normal cells. |
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