Akt inhibitor augments anti-proliferative efficacy of a dual mTORC1/2 inhibitor by FOXO3a activation in p53 mutated hepatocarcinoma cells

Abstract

Hepatocellular carcinoma (HCC) is one of the most common malignancy-related deaths. p53 mutation in HCC associates with worse clinicopathologic features including therapeutic limitation. A combination of targeted therapy may have some advantages. Akt/mTOR signaling contributes to the regulation of cell proliferation and cell death. Akt inhibitor (AZD5363) and mTORC1/2 dual inhibitor (AZD8055) are in a clinical trial for HCC and other cancers. In this study, we examined whether these inhibitors successfully induce antiproliferative activity in p53 mutant HCC cells, and the underlying mechanisms. We observed that a combination of AZD5363 and AZD8055 treatment synergizes antiproliferative activity on p53 mutated or wild-type HCC cell lines and induces apoptotic cell death. Mechanistic insights indicate that a combination of AZD5363 and AZD8055 activated FOXO3a to induce Bim-associated apoptosis in p53 mutated HCC cells, whereas cells retaining functional p53 enhanced Bax. siRNA-mediated knock-down of Bim or Bax prevented apoptosis in inhibitor-treated cells. We further observed a combination of treatment inhibits phosphorylation of FOXO3a and protects FOXO3a from MDM2 mediated degradation by preventing the phosphorylation of Akt and SGK1. FOXO3a accumulates in the nucleus under these conditions and induces Bim transcription in p53 mutant HCC cells. Combination treatment in the HCC cells expressing wild-type p53 causes interference of FOXO3a function for direct interaction with functional p53 and unable to induce Bim-associated cell death. On the other hand, Bim-associated cell death occurs in p53 mutant cells due to uninterrupted FOXO3a function. Overall, our findings suggested that a combined regimen of dual mTORC1/2 and Akt inhibitors may be an effective therapeutic strategy for HCC patients harboring p53 mutation.

Crebanine induces ROS-dependent apoptosis in human hepatocellular carcinoma cells via the AKT/FoxO3a signaling pathway

“…It has been shown to perform a different function in cell proliferation, differentiation, metabolism, and invasion and apoptosis ( Liang et al, 2020 ; Habrowska-Górczyńska et al, 2021 ). The PI3K/Akt pathway is regulated by upstream targets such as PTEN and it influences the expression of downstream targets such as GSK3-β, FoxO3a, β-catenin, p21, p27, and Mdm2 ( Fresno et al, 2004 ; Nogueira et al, 2008 ; Patra et al, 2021 ). Among them, FoxO3a is a member of the Forkhead box O family of transcription factors, which is often stimulated by PI3K/Akt signaling.…”

Luteolin inhibits triple-negative breast cancer by inducing apoptosis and autophagy through SGK1-FOXO3a-BNIP3 signaling

“…We further confirmed luteolin significantly suppressed Bcl-2 and increased Bax, indicating that BNIP3 can bind to Bcl-2 and form heterodimers to activate pro-apoptotic proteins, Bax, eventually resulting in apoptosis. In addition, some studies suggest that FOXO3a can activate apoptotic pathways by directly binding to the promoter region of the Bim gene to induce its expression ( Patra et al, 2021 ). In line with past studies, we also verified that luteolin could affect the Bim expression.…”

HRK inhibits colorectal cancer cells proliferation by suppressing the PI3K/AKT/mTOR pathway

“…Furthermore, overexpression of anti-apoptotic Bcl-2 family proteins can largely enhancement tumor development induced by oncogenes, although excessive expression of anti-apoptotic Bcl-2 family proteins alone may not lead to tumor development comparable to that of oncogenes themselves ( 31 ). Both growth factor secretion including FOXOs ( 46 , 47 ) and E2F1 ( 48 ) and the presence of other apoptotic stimuli can induce transcription of proteins containing only BH3 structures. In contrast, the activity of some transcription factors can be inhibited by AKT ( 47 ).…”

“…Both growth factor secretion including FOXOs ( 46 , 47 ) and E2F1 ( 48 ) and the presence of other apoptotic stimuli can induce transcription of proteins containing only BH3 structures. In contrast, the activity of some transcription factors can be inhibited by AKT ( 47 ). Thus, increased AKT activation may reduce HRK transcription.…”