Role of Akt and SRC Pathways in Exosome-mediated Migration of Homologous Lung Adenocarninoma Cells / 中国医科大学学报

Objective To investigate the effect of Exosomes derived from lung cancer cells on the migration of secretory cells and homologous tumor cells and to explore the role of PI3K/Akt and SRC signaling pathways in this process.Methods Exosomes were isolated from the supematant post density gradient centrifugation of A549,lung cancer cells.Morphology of the Exosomes was studied using transmission electron microscopy.Protein expression was analyzed using Western blotting.Cell migration was analyzed by a transwell assay.Results The double-membrane-bound Exosomes appeared as discal-shaped structures,30-100 nm in diameter.Western blotting showed that CD9 was abundant in the Exosomes.The Exosomes promoted the migration of A549 cells and their homologous tumor cells,HCC827 in a dose-dependent manner,accompanied by the activation of Akt and SRC.Conclusion The Exosomes derived from A549 (lung cancer) cells promote the migration of the secreting cells and the homologous tumor cells.The mechanism may be correlated with the activation of Akt and SRC.

Role of Akt and SRC Pathways in Exosome?mediated Proliferation of Homologous Lung Adenocarninoma Cells / 中国医科大学学报

Objective To explore the effect of Exosomes isolated from the A549 lung cancer cells on the proliferation of these cells and their ho?mologous tumor cells,HCC827,and the role of the PI3K/Akt and SRC signaling pathways in this process. Methods Exosomes were isolated from the supernatant after density gradient centrifugation of A549 cells. The Exosomes morphology was observed by transmission electron microscopy. The expression of the Exosome?specific proteins was analyzed using Western blotting. Cell proliferation was investigated using the MTT assay. Re?sults The A549?derived Exosomes were 30?100 nm in diameter and had a bilayer membrane.Western blotting showed that CD9 was detected in these Exosomes. The isolated Exosomes promoted the proliferation of the A549 and the HCC827 cells in a dose?and time?dependent manner,ac?companied by the activation of Akt and SRC. Conclusion Exosomes isolated from A549 cells promote the proliferation of the secreting cells and the homologous tumor cells in a dose?and time?dependent manner. The mechanism may be related to the activation of Akt and SRC.

Analysis of Clinical Significance of AKT3 Expression in Gastric Cancer Utilizing TCGA Datasets / 中国医科大学学报

Objective To investigate the prognostic value of AKT3 expression in gastric cancer. Methods AKT3 expression data in The Cancer Genome Atlas(TCGA)datasets and its clinical information were downloaded. Statistically assessed was performed for relationship with clinicopatho?logical factors and prognosis. Gene set enrichment analysis(GSEA)was used to predict the gene sets modulated by AKT3. Results The expres?sion of AKT3 was associated with T stage(P=0.001),TNM stage(P=0.049)and differentiation(P<0.001).High level of AKT3 expression indi?cates poor prognosis(P=0.001). AKT3 could regulate gene sets involving cell adhesion molecule,cytoskeleton regulation,focal adhesion and TGF?βsignaling pathway. Conclusion AKT3 could be used as a potential prognostic marker and a therapeutic target in gastric cancer.

E3 ubiquitin ligase Cbl-b potentiates the apoptotic action of arsenic trioxide by inhibiting the PI3K/Akt pathway

Arsenic trioxide (ATO) is a strong inducer of apoptosis in malignant hematological cells. Inducible phosphatidyl inositol 3 kinase (PI3K)-Akt activation promotes resistance to ATO. In the present study, we evaluated whether E3 ubiquitin ligase Cbl-b, a negative regulator of PI3K activation, is involved in the action of ATO. The effect of ATO on cell viability was measured by the Trypan blue exclusion assay or by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Apoptosis was determined by flow cytometry and protein expression was assayed by Western blotting. ATO decreased the viability of HL60 cells and induced cellular apoptosis, which was accompanied by transient activation of Akt. The PI3K/Akt inhibitor, LY294002, significantly increased ATO-induced apoptosis (P < 0.05). In addition, ATO up-regulated the expression of Cbl-b proteins. Furthermore, ATO inhibited cell viability with an IC50 of 18.54 μM at 24 h in rat basophilic leukemia-2H3 cells. ATO induced cellular apoptosis with transient activation of Akt and Cbl-b was also up-regulated. Rat basophilic leukemia-2H3 cells transfected with a dominant negative (DN) Cbl-b mutation showed overexpression of Cbl-b (DN) and enhanced Akt activation. Compared with cells transfected with vector, ATO-induced apoptosis was decreased and G2/M phase cells were increased at the same concentration (P < 0.05). The PI3K/Akt inhibitor, LY294002, re-sensitized Cbl-b (DN) overexpressing cells to ATO and reversed G2/M arrest (P < 0.05). Taken together, these results suggest that Cbl-b potentiates the apoptotic action of ATO by inhibition of the PI3K/Akt pathway.