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The hepatic stellate cells (HSCs) activation by myofibroblastic differentiation is critical for liver fibrosis. Crosstalk between stromal cells and tumor cells in the microenvironment alters the properties and facilitates the growth and metastasis of tumor cells. How mechanical stimuli originally stiffness of extracellular matrix (ECM) contribute to tumor development remains poorly understood. Here, we demonstrated that stiffness contributes to mechanosignal transduction in HSCs, which promotes hepatocellular carcinoma (HCC) cells growth and metastasis through secretion of FGF2. On stiffness matrix, HSCs activation was confirmed by immunofluorescence (IF) and Western blot (WB) for α-smooth muscle actin (SMA). Increasing matrix stiffness promoted HSCs activation by CD36-AKT-E2F3 mechanosignaling through shRNA-mediated E2F3 knockdown, AKT inhibitors, and CD36 shRNA. Moreover, ChIP-qPCR. Confirmed that E2F3 combined the promoter of FGF2, and stiffness promoted FGF2 expression. On a stiff matrix, HCC cells cultured with conditioned media (CM) from HSCs increased HCC cells growth and metastasis by binding FGFR1 to activate PI3K/AKT and MEK/ERK signaling pathways. Moreover, conditional E2F3 knockout mice were subjected to CCl4 treatment to assess the role of E2F3 in HSC activation. Additionally, the DEN-induced HCC model was also used to evaluate the role of E2F3 in liver fibrosis and HCC growth. In conclusion, we demonstrated that stiffness-induced HSC activation by E2F3 dependent. Stiffness activated CD36-AKT-E2F3 signaling and targeted FGF2 transcription, subsequently, activated HCC growth and metastasis by FGFR1-mediated PI3K/AKT and MEK/ERK signaling.

Previous evidences reveal that long non-coding RNA (lncRNA) down syndrome critical region 8 (DSCR8) involves in the progression of multiple cancers. However, the exact expression, function, and mechanism of DSCR8 in hepatocellular carcinoma (HCC) remain uncovered. In this study, real-time PCR in HCC tissues and cell lines indicated that DSCR8 expression was upregulated, while miR-485-5p was downregulated. MTT assay, plate clone formation, Edu assay, flow cytometry, and in vivo experiments indicated that DSCR8 promoted HCC cell proliferation and cycle, whereas accelerated cell apoptosis. Luciferase reporter gene assay, RIP assay, and rescue experiments demonstrated that DSCR8 functioned as a competing endogenous RNA (ceRNA) by sponging miR-485-5p in HCC cells. Furthermore, gain- and loss-of-function studies showed that miR-485-5p activated Wnt/β-catenin signal pathway by targeting Frizzled-7 (FZD7). Moreover, DSCR8 activated Wnt/β-catenin signal pathway to promote HCC progression by DSCR8/miR-485-5p/FZD7 axis. Statistical analysis revealed that DSCR8 and miR-485-5p were closely related to some malignant clinicopathological features and 5-year survival rates of HCC patients. Taken together, the present study reports for the first time that DSCR8 activates Wnt/β-catenin signal pathway to promote HCC progression by DSCR8/miR-485-5p/FZD7 axis. The findings provide promising and valuable strategies for targeted therapy of HCC.

Aberrant autophagic processes have been found to have fundamental roles in the pathogenesis of different kinds of tumors, including hepatocellular carcinoma (HCC). P300/CBP-associated factor (PCAF), a histone acetyltransferase (HAT), performs its function by acetylating both histone and non-histone proteins. Our previous studies showed that PCAF was downregulated in HCC tissues and its high expression was significantly associated with patient survival after surgery, serving as a prognostic marker. In this study we found that overexpression of PCAF induced autophagy of HCC cells and its knockdown depressed autophagy. As type II programmed cell death, autophagy induced by PCAF-elicited cell death in HCC cells. In vivo experiments confirmed that PCAF-induced autophagy inhibited tumor growth. Subsequent in vitro experiments showed that PCAF promoted autophagy by inhibiting Akt/mTOR signaling pathway. Our findings show that PCAF is a novel modulator of autophagy in HCC, and can serve as an attractive therapeutic strategy of HCC treatment.