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- Title
Loss of immunity-supported senescence enhances susceptibility to hepatocellular carcinogenesis and progression in Toll-like receptor 2-deficient mice.
- Authors
Lin, Heng; Yan, Jun; Wang, Ziyan; Hua, Fang; Yu, Jiaojiao; Sun, Wei; Li, Ke; Liu, Hong; Yang, Hongzhen; Lv, Qi; Xue, Jianfei; Hu, Zhuo-Wei
- Abstract
Hepatocellular carcinoma (HCC) is a complication at the endstage of chronic inflammatory liver diseases with dismal prognosis. Targeting of Toll-like receptor (TLR) 2 attenuates tumor metastases; we hypothesized that blocking TLR2 might also play a crucial role in reducing hepatocarcinogenesis. Surprisingly, we found that the genetic deletion of TLR2 increased susceptibility to diethylnitrosamine (DEN), a genotoxic carcinogen that can induce HCC. Indeed, TLR2-deficient mice showed a significant increase in carcinogenesis and progression of HCC as indicated by increases in tumor nodule size, tumor volume, and animal death. The enhanced susceptibility to DEN-induced HCC was associated with a broad-spectrum reduction in the immune response to DEN-induced liver injury. We found that TLR2 deficiency caused a decrease in the infiltration of macrophages and an attenuation of apoptosis signal regulating kinase 1 (ASK1) / p38 mitogen-activated protein kinase (p38 MAPK) / nuclear factor kappa B (NF-κB) signaling, which led to a decrease in the expression of interferon-gamma (IFN-γ), tumor necrosis factor alpha (TNF-α), interleukin (IL)-1α/β, IL-6, and Cxcl-2 as well as suppression of autophagy flux and increases in oxidative stress and p62 aggregation in liver tissue. The defects in immune networks resulted in suppressed p21- and p16/pRb-dependent senescence, which caused an increase in proliferation and a decrease in apoptotic and autophagy-associated cell death in mouse livers. Restoring cellular senescence and autophagy flux by treating TLR2-deficient mice with IFN-γ, a T helper 1 (Th1) cytokine and positive modulator of senescence and autophagy, could attenuate the carcinogenesis and progression of HCC associated with TLR2-deficient animals.
- Publication
Hepatology (Baltimore, Md.), 2013, Vol 57, Issue 1, p171
- ISSN
1527-3350
- Publication type
Journal Article
- DOI
10.1002/hep.25991