AKT Kinase Inhibitor

AKT Kinase Inhibitor

Didymin Alleviates Hepatic Fibrosis Through Inhibiting ERK and PI3K/Akt Pathways via Regulation of Raf Kinase Inhibitor Protein.[Pubmed:27997902]

Cell Physiol Biochem. 2016;40(6):1422-1432.

BACKGROUND: Didymin has been reported to have anti-cancer potential. However, the effect of didymin on liver fibrosis remains illdefined. METHODS: Hepatic fibrosis was induced by CCl4 in rats. The effects of didymin on liver pathology and collagen accumulation were observed by hematoxylin-eosin and Masson's trichrome staining, respectively. Serum transaminases activities and collagen-related indicators levels were determined by commercially available kits. Moreover, the effects of didymin on hepatic stellate cell apoptosis and cell cycle were analyzed by flow cytometry. Mitochondrial membrane potential was detected by using rhodamine-123 dye. The expression of Raf kinase inhibitor protein (RKIP) and the phosphorylation of the ERK/MAPK and PI3K/Akt pathways were assessed by Western blot. RESULTS: Didymin significantly ameliorated chronic liver injury and collagen deposition. It strongly inhibited hepatic stellate cells proliferation, induced apoptosis and caused cell cycle arrest in G2/M phase. Moreover, didymin notably attenuated mitochondrial membrane potential, accompanied by release of cytochrome C. Didymin significantly inhibited the ERK/MAPK and PI3K/Akt pathways. The effects of didymin on the collagen accumulation in rats and on the biological behaviors of hepatic stellate cells were largely abolished by the specific RKIP inhibitor locostatin. CONCLUSION: Didymin alleviates hepatic fibrosis by inhibiting ERK/MAPK and PI3K/Akt pathways via regulation of RKIP expression.

PAK1 Is a Novel Therapeutic Target in Tyrosine Kinase Inhibitor-Resistant Lung Adenocarcinoma Activated by the PI3K/AKT Signaling Regardless of EGFR Mutation.[Pubmed:27178741]

Clin Cancer Res. 2016 Nov 1;22(21):5370-5382.

PURPOSE: EGFR mutation as a biomarker has documented that EGFR-mutant patients will derive clinical benefit from tyrosine kinase inhibitor (TKI) treatment. Unfortunately, most patients show TKI resistance and tumor recurrence after therapy. Therefore, we expected that an adjuvant biomarker other than EGFR mutation is needed for predicting TKI resistance. EXPERIMENTAL DESIGN: Molecular manipulations were performed to verify whether TKI resistance mediated by p21-activated kinase (PAK1) could be through increasing Mcl-1 protein stability via the PI3K/AKT/C/EBP-beta/miR-145 cascade. Xenograft mouse models were used to confirm the mechanistic action of PAK1 on TKI resistance. Forty-six tumor tissues from patients with lung adenocarcinoma who received TKI therapy were collected to evaluate PAK1 and E-cadherin mRNA expressions by real-time PCR. The association of PAK1 and E-cadherin mRNA expressions with tumor response to TKI treatment and outcomes was evaluated. RESULTS: We demonstrate that PAK1 confers TKI resistance in EGFR-mutant cells as well as in EGFR-wild-type cells. Mechanistically, the positive feedback loop of PAK1/PI3K/AKT/C/EBP-beta/miR-145 cascades persistently activates the PI3K/AKT signaling pathway to protect Mcl-1 degradation by Fbw7, which results, in turn, in TKI resistance and cell invasion via epithelial-to-mesenchymal transition due to a decrease in E-cadherin expression. The mechanism underlying the cell model is further confirmed in xenograft tumors. Among patients, high-PAK1 or low-E-cadherin tumors more commonly exhibited an unfavorable response to TKI and poorer outcome compared with low-PAK1 or low-E-cadherin tumors. CONCLUSIONS: The combination of TKI with AKT inhibitor might confer TKI sensitivity and in turn improve outcomes in patients with lung adenocarcinoma who harbored high PAK1 mRNA-expressing tumors. Clin Cancer Res; 22(21); 5370-82. (c)2016 AACR.

Selective elimination of neuroblastoma cells by synergistic effect of Akt kinase inhibitor and tetrathiomolybdate.[Pubmed:28244639]

J Cell Mol Med. 2017 Sep;21(9):1859-1869.

Neuroblastoma is the most common extracranial solid tumour of infancy. Pathological activation of glucose consumption, glycolysis and glycolysis-activating Akt kinase occur frequently in neuroblastoma cells, and these changes correlate with poor prognosis of patients. Therefore, several inhibitors of glucose utilization and the Akt kinase activity are in preclinical trials as potential anti-cancer drugs. However, metabolic plasticity of cancer cells might undermine efficacy of this approach. In this work, we identified oxidative phosphorylation as compensatory mechanism preserving viability of neuroblastoma cells with inhibited glucose uptake/Akt kinase. It was oxidative phosphorylation that maintained intracellular level of ATP and proliferative capacity of these cells. The oxidative phosphorylation inhibitors (rotenone, tetrathiomolybdate) synergized with inhibitor of the Akt kinase/glucose uptake in down-regulation of both viability of neuroblastoma cells and clonogenic potential of cells forming neuroblastoma spheroids. Interestingly, tetrathiomolybdate acted as highly specific inhibitor of oxygen consumption and activator of lactate production in neuroblastoma cells, but not in normal fibroblasts and neuronal cells. Moreover, the reducing effect of tetrathiomolybdate on cell viability and the level of ATP in the cells with inhibited Akt kinase/glucose uptake was also selective for neuroblastoma cells. Therefore, efficient elimination of neuroblastoma cells requires inhibition of both glucose uptake/Akt kinase and oxidative phosphorylation activities. The use of tetrathiomolybdate as a mitochondrial inhibitor contributes to selectivity of this combined treatment, preferentially targeting neuroblastoma cells.