SCYL3, as a novel binding partner and regulator of ROCK2, promotes hepatocellular carcinoma progression

SMARCA4 (BRG1) activates ABCC3 transcription to promote hepatocellular carcinogenesis

AIMS

Hepatocellular carcinoma (HCC) is a lead cause of cancer-related deaths. In the present study we investigated the role of Brahma-related gene 1 (BRG1), a chromatin remodeling protein, in HCC the pathogenesis focusing on identifying novel transcription targets.

METHODS AND MATERIALS

Hepatocellular carcinogenesis was modeled in mice by diethylnitrosamine (DEN). Cellular transcriptome was evaluated by RNA-seq.

RESULTS

Hepatocellular carcinoma was appreciably retarded in BRG1 knockout mice compared to wild type littermates. Transcriptomic analysis identified ATP Binding Cassette Subfamily C Member 3 (ABCC3) as a novel target of BRG1. BRG1 over-expression in BRG1low HCC cells (HEP1) up-regulated whereas BRG1 depletion in BRG1high HCC cells (SNU387) down-regulated ABCC3 expression. Importantly, BRG1 was detected to directly bind to the ABCC3 promoter to activate ABCC3 transcription. BRG1 over-expression in HEP1 cells promoted proliferation and migration, both of which were abrogated by ABCC3 silencing. On the contrary, BRG1 depletion in SNU387 cells decelerated proliferation and migration, both of which were rescued by ABCC3 over-expression. Importantly, high BRG1/ABCC3 expression predicted poor prognosis in HCC patients. Mechanistically, ABCC3 regulated hepatocellular carcinogenesis possibly by influencing lysosomal homeostasis.

SIGNIFICANCE

In conclusion, our data suggest that targeting BRG1 and its downstream target ABCC3 can be considered as a reasonable approach for the intervention of hepatocellular carcinoma.

Crosstalk between endothelial progenitor cells and HCC through periostin/CCL2/CD36 supports formation of the pro-metastatic microenvironment in HCC

Metastasis causes most cancer-related deaths, and the role and mechanism of periostin (POSTN) in the metastasis of hepatocellular carcinoma (HCC) remain undiscovered. In this study, DEN and HTVi HCC models were performed in hepatic-specific Postn ablation and Postn knock-in mouse to reveal the role of POSTN in HCC metastasis. Furthermore, POSTN was positively correlated with circulating EPCs level and promoted EPC mobilization and tumour infiltration. POSTN also mediated the crosstalk between HCC and EPCs, which promoted metastasis ability and upregulated CD36 expression in HCC through indirect crosstalk. Chemokine arrays further revealed that hepatic-derived POSTN induced elevated CCL2 expression and secretion in EPCs, and CCL2 promoted prometastatic traits in HCC. Mechanistic studies showed that POSTN upregulated CCL2 expression in EPCs via the αvβ3/ILK/NF-κB pathway. CCL2 further induced CD36 expression via the CCR2/STAT3 pathway by directly binding to the promoter region of CD36. Finally, CD36 was verified to have a prometastatic role in vitro and to be correlated with POSTN expression, metastasis and recurrence in HCC in clinical samples. Our findings revealed that crosstalk between HCC and EPCs is mediated by periostin/CCL2/CD36 signalling which promotes HCC metastasis and emphasizes a potential therapeutic strategy for preventing HCC metastasis.

Identification of common factors among fibrosarcoma, rhabdomyosarcoma, and osteosarcoma by network analysis

Sarcoma cancers are uncommon malignant tumors, and there are many subgroups, including fibrosarcoma (FS), which mainly affects middle-aged and older adults in deep soft tissues. Rhabdomyosarcoma (RMS), on the other hand, is the most common soft-tissue sarcoma in children and is located in the head and neck area. Osteosarcomas (OS) is the predominant form of primary bone cancer among young adults, primarily resulting from sporadically random mutations. This frequently results in the dissemination of cancer cells to the lungs, commonly known as metastasis. Mesodermal cells are the origin of sarcoma cancers. In this study, a rather radical approach has been applied. Instead of comparing homogenous cancer types, we focus on three main subtypes of sarcoma: fibrosarcoma, rhabdomyosarcoma, and osteosarcoma, and compare their gene expression with normal cell groups to identify the differentially expressed genes (DEGs). Next, by applying protein-protein interaction (PPI) network analysis, we determine the hub genes and crucial factors, such as transcription factors (TFs), affected by these types of cancer. Our findings indicate a modification in a range of pathways associated with cell cycle, extracellular matrix, and DNA repair in these three malignancies. Results showed that fibrosarcoma (FS), rhabdomyosarcoma (RMS), and osteosarcoma (OS) had 653, 1270, and 2823 differentially expressed genes (DEGs), respectively. Interestingly, there were 24 DEGs common to all three types. Network analysis showed that the fibrosarcoma network had two sub-networks identified in FS that contributed to the catabolic process of collagen via the G-protein coupled receptor signaling pathway. The rhabdomyosarcoma network included nine sub-networks associated with cell division, extracellular matrix organization, mRNA splicing via spliceosome, and others. The osteosarcoma network has 13 sub-networks, including mRNA splicing, sister chromatid cohesion, DNA repair, etc. In conclusion, the common DEGs identified in this study have been shown to play significant and multiple roles in various other cancers based on the literature review, indicating their significance.

Ubiquitin specific peptidase 47 contributes to liver regeneration

AIMS

Hepatocytes resume proliferation following liver injuries to compensate for the loss of liver mass. Robust liver regeneration is an intrinsic and pivotal process that facilitates restoration of liver anatomy and function. In the present study we investigated the role of ubiquitin-specific peptidase 47 (USP47) in liver regeneration.

METHODS AND MATERIALS

Proliferation of hepatocytes was evaluated by Ki67 staining in vivo and EdU incorporation in vitro. DNA-protein interaction was evaluated by chromatin immunoprecipitation (ChIP).

RESULTS

USP47 expression was up-regulated in hepatocytes isolated from mice subjected to partial hepatectomy (PHx) or exposed to HGF treatment. Ingenuity pathway analysis revealed E2F1 as a primary regulator of USP47 transcription. Reporter assay and ChIP assay confirmed that E2F1 directly bound to the USP47 promoter and activated USP47 transcription. Consistently, E2F1 knockdown abrogated USP47 induction by HGF. Compared to the wild type littermates, USP47 knockout mice displayed compromised liver regeneration following PHx. In addition, USP47 inhibition by a small-molecule compound impaired liver regeneration in mice. On the contrary, USP47 over-expression enhanced proliferation of hepatocytes in vitro and promoted liver regeneration in mice. Importantly, a positive correlation between USP47 expression and hepatocyte proliferation was identified in patients with acute liver failure (ALF).

SIGNIFICANCE

Our data suggest that USP47, transcriptionally activated by E2F1, plays an essential role in liver regeneration.

Background and roles: myosin in autoimmune diseases

The myosin superfamily is a group of molecular motors. Autoimmune diseases are characterized by dysregulation or deficiency of the immune tolerance mechanism, resulting in an immune response to the human body itself. The link between myosin and autoimmune diseases is much more complex than scientists had hoped. Myosin itself immunization can induce experimental autoimmune diseases of animals, and myosins were abnormally expressed in a number of autoimmune diseases. Additionally, myosin takes part in the pathological process of multiple sclerosis, Alzheimer's disease, Parkinson's disease, autoimmune myocarditis, myositis, hemopathy, inclusion body diseases, etc. However, research on myosin and its involvement in the occurrence and development of diseases is still in its infancy, and the underlying pathological mechanisms are not well understood. We can reasonably predict that myosin might play a role in new treatments of autoimmune diseases.

TRIB1 regulates liver regeneration by antagonizing the NRF2-mediated antioxidant response

Robust regenerative response post liver injuries facilitates the architectural and functional recovery of the liver. Intrahepatic redox homeostasis plays a key role in liver regeneration. In the present study, we investigated the contributory role of Tribbles homolog 1 (Trib1), a pseudokinase, in liver regeneration and the underlying mechanism. We report that Trib1 expression was transiently down-regulated in animal and cell models of liver regeneration. Further analysis revealed that hepatocyte growth factor (HGF) repressed Trib1 transcription by evicting liver X receptor (LXRα) from the Trib1 promoter. Knockdown of Trib1 enhanced whereas over-expression of Trib1 suppressed liver regeneration after partial hepatectomy in mice. Of interest, regulation of liver regenerative response by Trib1 coincided with alterations of intracellular ROS levels, GSH levels, and antioxidant genes. Transcriptional assays suggested that Trib1 influenced cellular redox status by attenuating nuclear factor erythroid 2-related factor 2 (Nrf2) activity. Mechanistically, Trib1 interacted with the C-terminus of Nrf2 thus masking a potential nuclear localization signal (NLS) and blocking nuclear accumulation of Nrf2. Finally, correlation between Trib1 expression, Nrf2 nuclear localization, and cell proliferation was identified in liver specimens taken from patients with acute liver failure. In conclusion, our data unveil a novel pathway that depicts Trib1 as a critical link between intracellular redox homeostasis and cell proliferation in liver regeneration.