Downregulation of SSR2 Enhances Hepatocellular Carcinoma Cisplatin Sensitivity via the Hippo Pathway.

Chemotherapy resistance is an obstacle to promoting the survival of patients with hepatocellular carcinoma (HCC). Thus, finding promising therapeutic targets to enhance HCC chemotherapy is necessary. Signal sequence receptor subunit (SSR2) expression analysis was performed using quantitative real time polymerase chain reaction (qPCR) and Western blotting assays. Colony formation, apoptosis, anchorage-independent growth assay, and in vivo animal models were used to investigate the effect of SSR2 expression on the resistance of HCC cells to Cisplatin (DDP). Western blotting and luciferase reporter gene techniques were used to explore the molecular mechanism of SSR2 on the resistance of HCC cells to DDP. We found that the SSR2 is upregulated in HCC and associated with poor survival. Further analysis showed that the downregulation of SSR2 increased the sensitivity of HCC to DDP. Mechanically, SSR2 inhibited the Yes-associated protein (YAP) phosphorylation and promoted the transcription of Hippo signaling downstream genes. Finally, the Hippo pathway inhibitor can suppress colony formation and tumorigenesis arising from SSR2 upregulation. Our study shows that SSR2 is important in HCC progression via the Hippo pathway. Thus, targeting the SSR2/Hippo axis might be a potential strategy for overcoming HCC resistance to DDP.

Ye R ，Yin L ，Ge Y ，Zhu X ，Xiao Y ，Fang C ，Liu Q ，Zhang H ，Li H ，Xie B ... -  《-》

c-Src promotes the growth and tumorigenesis of hepatocellular carcinoma via the Hippo signaling pathway.

We investigated the association between c-Src and the progression of hepatocellular carcinoma (HCC) and its underlying mechanisms. The relationship between c-Src expression and the occurrence and development of HCC was explored using GEPIA and further confirmed by western blotting analysis and real-time quantitative PCR. CCK-8, flow cytometry, Transwell, and wound-healing assays were conducted to analyze the effects of c-Src on the growth, cell cycle, apoptosis, migration, and infiltration of HCC cells. Mouse models of transplanted xenogeneic human tumors were constructed to explore the effects of c-Src on HCC tumor growth. Compared with that in adjacent normal liver tissues, the expression level of c-Src in HCC tissues was significantly increased and was negatively correlated with patient survival. These findings are consistent with those in the GEPIA database. Downregulation of c-Src expression can inhibit the growth, infiltration, and migration of HCC cells. c-Src impeded the translocation of YAP from the nucleus to the cytoplasm and promoted Yes-associated protein transcriptional activity. In vivo experiments showed that c-Src inhibition suppressed tumor growth in mice. We found that c-Src can promote the growth and tumorigenesis of HCC cells by activating the Hippo signaling pathway.

Yang J ，Zhang X ，Liu L ，Yang X ，Qian Q ，Du B ... -  《-》

Evodiamine inhibits proliferation and promotes apoptosis of hepatocellular carcinoma cells via the Hippo-Yes-Associated Protein signaling pathway.

Dysfunction of the Hippo-Yes-Associated Protein (YAP) signaling pathway is known to be associated with hepatocellular carcinoma (HCC). Evodiamine (Evo), a plant-derived bioactive alkaloid, exerts inhibitory effects on cancer. However, the precise influence of Evo on HCC and its potential effects on Hippo-YAP signaling have yet to be ascertained. Here, the effects of Evo on cell proliferation and apoptosis were evaluated using HCC cell lines (HepG2 and Bel-7402) and nude mice with xenograft tumors. We further investigated whether Evo exerts anti-HCC activity through effects on Hippo-YAP signaling in vitro with the aid of XMU-MP-1, an inhibitor of the key component of this pathway, mammalian sterile 20-like kinase 1/2. Cell proliferation and apoptosis were assessed using 5-ethynyl-2'-deoxyuridine staining, colony formation, flow cytometry, hematoxylin-eosin and dUTP nick-end labeling experiments. Bioinformatics and real-time quantitative polymerase chain reaction (RT-qPCR) arrays were performed to determine the associations among Evo, HCC progression and the Hippo-YAP pathway. The expression patterns of components of Hippo-YAP signaling and apoptotic genes were further examined via RT-qPCR and immunoblotting. Evo inhibited proliferation and promoted apoptosis of HCC cell lines in vitro, and attenuated xenograft tumor formation in nude mice in vivo. Mechanistically, Evo treatment stimulated the Hippo-YAP signaling pathway. In vitro, the effects of Evo on HCC cell proliferation and apoptosis were alleviated by XMU-MP-1. Our collective results revealed that the anti-HCC effects of Evo were correlated with the Hippo-YAP signaling pathway.

Zhao S ，Xu K ，Jiang R ，Li DY ，Guo XX ，Zhou P ，Tang JF ，Li LS ，Zeng D ，Hu L ，Ran JH ，Li J ，Chen DL ... -  《-》

Epigenetic regulation of DNA repair gene program by Hippo/YAP1-TET1 axis mediates sorafenib resistance in HCC.

Hepatocellular carcinoma (HCC) is a malignancy that occurs worldwide and is generally associated with poor prognosis. The development of resistance to targeted therapies such as sorafenib is a major challenge in clinical cancer treatment. In the present study, Ten-eleven translocation protein 1 (TET1) was found to be highly expressed in sorafenib-resistant HCC cells and knockdown of TET1 can substantially improve the therapeutic effect of sorafenib on HCC, indicating the potential important roles of TET1 in sorafenib resistance in HCC. Mechanistic studies determined that TET1 and Yes-associated protein 1 (YAP1) synergistically regulate the promoter methylation and gene expression of DNA repair-related genes in sorafenib-resistant HCC cells. RNA sequencing indicated the activation of DNA damage repair signaling was extensively suppressed by the TET1 inhibitor Bobcat339. We also identified TET1 as a direct transcriptional target of YAP1 by promoter analysis and chromatin-immunoprecipitation assays in sorafenib-resistant HCC cells. Furthermore, we showed that Bobcat339 can overcome sorafenib resistance and synergized with sorafenib to induce tumor eradication in HCC cells and mouse models. Finally, immunostaining showed a positive correlation between TET1 and YAP1 in clinical samples. Our findings have identified a previously unrecognized molecular pathway underlying HCC sorafenib resistance, thus revealing a promising strategy for cancer therapy.

Mo C ，You W ，Rao Y ，Lin Z ，Wang S ，He T ，Shen H ，Li X ，Zhang R ，Li B ... -  《-》

Long non-coding RNA LOC107985656 represses the proliferation of hepatocellular carcinoma cells through activation of the tumor-suppressive Hippo pathway.

Zeng Y ，Xu Q ，Xu N 《-》