Faculty Opinions recommendation of Rpn10 promotes tumor progression by regulating hypoxia-inducible factor 1 alpha through the PTEN/Akt signaling pathway in hepatocellular carcinoma.

Mild hypoxia (5% O2) as well as FGFR1-induced activation of phosphatidylinositol-4,5-bisphosphate 3-kinase/protein kinase B (PI3K/AKT) and MAPK signaling pathways markedly support pluripotency in human pluripotent stem cells (hPSCs). This study demonstrates that the pluripotency-promoting PI3K/AKT signaling pathway is surprisingly attenuated in mild hypoxia compared to the 21% O2 environment. Hypoxia is known to be associated with lower levels of reactive oxygen species (ROS), which are recognized as intracellular second messengers capable of upregulating the PI3K/AKT signaling pathway. Our data denote that ROS downregulation results in pluripotency upregulation and PI3K/AKT attenuation in a hypoxia-inducible factor 1 (HIF-1)-dependent manner in hPSCs. Using specific MAPK inhibitors, we show that the MAPK pathway also downregulates ROS and therefore attenuates the PI3K/AKT signaling—this represents a novel interaction between these signaling pathways. This inhibition of ROS initiated by MEK1/2–ERK1/2 may serve as a negative feedback loop from the MAPK pathway toward FGFR1 and PI3K/AKT activation. We further describe the molecular mechanism resulting in PI3K/AKT upregulation in hPSCs—ROS inhibit the PI3K's primary antagonist PTEN and upregulate FGFR1 phosphorylation. These novel regulatory circuits utilizing ROS as second messengers may contribute to the development of enhanced cultivation and differentiation protocols for hPSCs. Since the PI3K/AKT pathway often undergoes an oncogenic transformation, our data could also provide new insights into the regulation of cancer stem cell signaling.

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miR-340 Inhibits the Development of Hepatocellular Carcinoma by Down-Regulating Akt Signaling Pathway

Journal of Biomaterials and Tissue Engineering ◽

10.1166/jbt.2021.2590 ◽

2021 ◽

Vol 11 (9) ◽

pp. 1785-1791

Author(s):

Tangpeng Xu ◽

Changli Ruan ◽

Xu Bin ◽

Mengxue Hu

Keyword(s):

Hepatocellular Carcinoma ◽

Cell Proliferation ◽

Signaling Pathway ◽

Akt Signaling ◽

Pathological Grade ◽

Akt Signaling Pathway ◽

Invasion And Migration ◽

Proliferation Ability ◽

And Migration ◽

Cancer Tissues

Hepatocellular carcinoma (HCC) is a serious threat to human health. miR-340 participates in HCC pathogenesis, but its specific mechanism is not completely clear. Therefore, our study assessed the mechanism by how miR-340 involves in HCC. The cancer tissues and paracancerous tissues of HCC patients were collected. miR-340 mimics/NC and Akt siRNA were transfected into HepG2 cells followed by analysis of miR-304 and EMT-related molecules expression by Real-time PCR, cell invasion and migration by Transwell assay, cell proliferation ability by CCK8 assay as well as p-Akt and p-mTOR level by Western blot. miR-340 in HCC tissues was significantly downregulated compared to adjacent tissues (P <0.001). With increased pathological grade, miR-340 expression was decreased gradually. p-Akt and p-mTOR in HCC tissues was significantly upregulated and elevated gradually with increased pathological grade. p-Akt and p-mTOR was negatively associated with miR-340 (P <0.001). After overexpression of miR-340, HepG2 cell proliferation, invasion, migration and epithelialization were significantly inhibited, and p-Akt and p-mTOR was reduced. When Akt expression was interfered with siRNA, cell proliferation and epithelialization was further inhibited. miR-340 inhibits the development of hepatocellular carcinoma through Akt signaling pathway.

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