SEPT6 drives hepatocellular carcinoma cell proliferation, migration and invasion via the Hippo/YAP signaling pathway

The MexTAg collaborative cross: host genetics affects asbestos related disease latency, but has little influence once tumours develop

Objectives: This study combines two innovative mouse models in a major gene discovery project to assess the influence of host genetics on asbestos related disease (ARD). Conventional genetics studies provided evidence that some susceptibility to mesothelioma is genetic. However, the identification of host modifier genes, the roles they may play, and whether they contribute to disease susceptibility remain unknown. Here we report a study designed to rapidly identify genes associated with mesothelioma susceptibility by combining the Collaborative Cross (CC) resource with the well-characterised MexTAg mesothelioma mouse model. Methods: The CC is a powerful mouse resource that harnesses over 90% of common genetic variation in the mouse species, allowing rapid identification of genes mediating complex traits. MexTAg mice rapidly, uniformly, and predictably develop mesothelioma, but only after asbestos exposure. To assess the influence of host genetics on ARD, we crossed 72 genetically distinct CC mouse strains with MexTAg mice and exposed the resulting CC-MexTAg (CCMT) progeny to asbestos and monitored them for traits including overall survival, the time to ARD onset (latency), the time between ARD onset and euthanasia (disease progression) and ascites volume. We identified phenotype-specific modifier genes associated with these traits and we validated the role of human orthologues in asbestos-induced carcinogenesis using human mesothelioma datasets. Results: We generated 72 genetically distinct CCMT strains and exposed their progeny (2,562 in total) to asbestos. Reflecting the genetic diversity of the CC, there was considerable variation in overall survival and disease latency. Surprisingly, however, there was no variation in disease progression, demonstrating that host genetic factors do have a significant influence during disease latency but have a limited role once disease is established. Quantitative trait loci (QTL) affecting ARD survival/latency were identified on chromosomes 6, 12 and X. Of the 97-protein coding candidate modifier genes that spanned these QTL, eight genes (CPED1, ORS1, NDUFA1, HS1BP3, IL13RA1, LSM8, TES and TSPAN12) were found to significantly affect outcome in both CCMT and human mesothelioma datasets. Conclusion: Host genetic factors affect susceptibility to development of asbestos associated disease. However, following mesothelioma establishment, genetic variation in molecular or immunological mechanisms did not affect disease progression. Identification of multiple candidate modifier genes and their human homologues with known associations in other advanced stage or metastatic cancers highlights the complexity of ARD and may provide a pathway to identify novel therapeutic targets.

Co-existence of KMT2A::SEPTIN6 fusion and DIS3 variant in a pediatric case with acute myeloid leukemia: a case report and literature review

The lysine(K)-specific methyltransferase 2A gene (KMT2A), previously known as mixed lineage leukemia (MLL), frequently rearranged in acute leukemia, belongs to one of the most promiscuous genes and has been found fused to more than 80 different partners. KMT2A::SEPTIN6 fusion is a relatively uncommon rearrangement observed in pediatric acute myeloid leukemia (AML) patients, some of which may harbor other mutations. We herein report a case of AML-M4-infant with KMT2A::SEPTIN6 fusion and DIS3 variant. The 8-month-old girl presented with leukocytosis, anemia and thrombocytopenia. A bone marrow smear disclosed that 64% of the total nucleated cells were blasts. Karyotype analysis showed 46,X,t(X;11)(q24;q23)[10]/46,XX[10]. Fluorescence in situ hybridization analysis suggested a possible break in the KMT2A gene. After whole transcriptome sequencing, Exon 9 of KMT2A was fused in-frame with Exon 2 of SEPTIN6. This is a typical type of chromosomal rearrangement leading to the KMT2A::SEPTIN6 fusion. Meanwhile, DIS3 variant [c.2065C>T, p.R689X, variant allele frequency (VAF): 39.8%] was identified. KMT2A::SEPTIN6 fusion has been associated with the pathogenesis of AML, whereas DIS3 variants are relatively rare genetic events in pediatric AML. Regrettably, the relatives disagreed with the combination chemotherapy, and the patient eventually died of progressive disease. In conclusion, our findings provide a foundation for a better understanding of the genotypic profile of KMT2A::SEPTIN6 associated AML, and the co-existence of KMT2A::SEPTIN6 and DIS3 variant might contribute to the disease progression and transformation of AML.

Targeting B4GALT7 suppresses the proliferation, migration and invasion of hepatocellular carcinoma through the Cdc2/CyclinB1 and miR-338-3p/MMP2 pathway

Background

As a three-dimensional network involving glycosaminoglycans (GAGs), proteoglycans (PGs) and other glycoproteins, the role of extracellular matrix (ECM) in tumorigenesis is well revealed. Abnormal glycosylation in liver cancer is correlated with tumorigenesis and chemoresistance. However, the role of galactosyltransferase in HCC (hepatocellular carcinoma) is largely unknown.

Methods

Here, the oncogenic functions of B4GALT7 (beta-1,4-galactosyltransferase 7) were identified in HCC by a panel of in vitro experiments, including MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide), colony formation, transwell and flow cytometry assay. The expression of B4GALT7 in HCC cell lines and tissues were examined by qPCR (real-time quantitative polymerase chain reaction) and western blot assay. The binding between B4GALT7 and miR-338-3p was examined by dual-luciferase reporter assay.

Results

B4GALT7 encodes galactosyltransferase I and it is highly expressed in HCC cells and human HCC tissues compared with para-tumor specimens. MiR-338-3p was identified to bind the 3' UTR (untranslated region) of B4GALT7. Highly expressed miR-338-3p suppressed HCC cell invasive abilities and rescued the tumor-promoting effect of B4GALT7 in HCC. ShRNA (short hairpin RNA) mediated B4GALT7 suppression reduced HCC cell invasive abilities, and inhibited the expression of MMP-2 and Erk signaling.

Conclusion

These findings identified B4GALT7 as a potential prognostic biomarker and therapeutic target for HCC.

Migration of Myogenic Cells Is Highly Influenced by Cytoskeletal Septin7

Septin7 as a unique member of the GTP binding protein family, is widely expressed in the eukaryotic cells and considered to be essential in the formation of hetero-oligomeric septin complexes. As a cytoskeletal component, Septin7 is involved in many important cellular processes. However, its contribution in striated muscle physiology is poorly described. In skeletal muscle, a highly orchestrated process of migration is crucial in the development of functional fibers and in regeneration. Here, we describe the pronounced appearance of Septin7 filaments and a continuous change of Septin7 protein architecture during the migration of myogenic cells. In Septin7 knockdown C2C12 cultures, the basic parameters of migration are significantly different, and the intracellular calcium concentration change in migrating cells are lower compared to that of scrambled cultures. Using a plant cytokinin, forchlorfenuron, to dampen septin dynamics, the altered behavior of the migrating cells is described, where Septin7-depleted cells are more resistant to the treatment. These results indicate the functional relevance of Septin7 in the migration of myoblasts, implying its contribution to muscle myogenesis and regeneration.

Septin11 promotes hepatocellular carcinoma cell motility by activating RhoA to regulate cytoskeleton and cell adhesion

Septins as GTPases in the cytoskeleton, are linked to a broad spectrum of cellular functions, including cell migration and the progression of hepatocellular carcinoma (HCC). However, roles of SEPT11, the new member of septin, have been hardly understood in HCC. In the study, the clinical significance and biological function of SEPT11 in HCC was explored. SEPT11 was screened out by combining ATAC-seq with mRNA-seq. Role of SEPT11 in HCC was further investigated by using overexpression, shRNA and CRISPR/Cas9-mediated SEPT11-knockout cells or in vivo models. We found RNA-seq and ATAC-seq highlights LncRNA AY927503 (AY) induced SEPT11 transcription, resulting in Rho GTPase activation and cytoskeleton actin aggregation. The GTP-binding protein SEPT11 is thus considered, as a downstream factor of AY, highly expressed in various tumors, including HCC, and associated with poor prognosis of the patients. In vitro, SEPT11 overexpression promotes the migration and invasion of HCC cells, while SEPT11-knockout inhibits migration and invasion. In vivo, SEPT11-overexpressed HCC cells show high metastasis incidents but don't significantly affect proliferation. Meanwhile, we found SEPT11 targets RhoA, thereby regulating cytoskeleton rearrangement and abnormal cell adhesion through ROCK1/cofilin and FAK/paxillin signaling pathways, promoting invasion and migration of HCC. Further, we found SEPT11 facilitates the binding of GEF-H1 to RhoA, which enhances the activity of RhoA. Overall, our study confirmed function of SEPT11 in promoting metastasis in HCC, and preliminarily explored its related molecular mechanism. SEPT11 acts as an oncogene in HCC, also draws further interest regarding its clinical application as a potential therapeutic target.

The emerging importance role of m6A modification in liver disease

N6-methyladenosine (m6A) modification, as one of the most common types of inner RNA modification in eukaryotes, plays a multifunctional role in normal and abnormal biological processes. This type of modification is modulated by m6A writer, eraser and reader, which in turn impact various processes of RNA metabolism, such as RNA processing, translation, nuclear export, localization and decay. The current academic view holds that m6A modification exerts a crucial role in the post-transcriptional modulation of gene expression, and is involved in multiple cellular functions, developmental and disease processes. However, the potential molecular mechanism and specific role of m6A modification in the development of liver disease have not been fully elucidated. In our review, we summarized the latest research progress on m6A modification in liver disease, and explored how these novel findings reshape our knowledge of m6A modulation of RNA metabolism. In addition, we also illustrated the effect of m6A on liver development and regeneration to prompt further exploration of the mechanism and role of m6A modification in liver physiology and pathology, providing new insights and references for the search of potential therapeutic targets for liver disease.

Coordinated regulation of Cdc42ep1, actin, and septin filaments during neural crest cell migration

The septin cytoskeleton has been demonstrated to interact with other cytoskeletal components to regulate various cellular processes, including cell migration. However, the mechanisms of how septin regulates cell migration are not fully understood. In this study, we use the highly migratory neural crest cells of frog embryos to examine the role of septin filaments in cell migration. We found that septin filaments are required for the proper migration of neural crest cells by controlling both the speed and the direction of cell migration. We further determined that septin filaments regulate these features of cell migration by interacting with actin stress fibers. In neural crest cells, septin filaments co-align with actin stress fibers, and the loss of septin filaments leads to impaired stability and contractility of actin stress fibers. In addition, we showed that a partial loss of septin filaments leads to drastic changes in the orientations of newly formed actin stress fibers, suggesting that septin filaments help maintain the persistent orientation of actin stress fibers during directed cell migration. Lastly, our study revealed that these activities of septin filaments depend on Cdc42ep1, which colocalizes with septin filaments in the center of neural crest cells. Cdc42ep1 interacts with septin filaments in a reciprocal manner, with septin filaments recruiting Cdc42ep1 to the cell center and Cdc42ep1 supporting the formation of septin filaments.

Septins as membrane influencers: direct play or in association with other cytoskeleton partners

The cytoskeleton comprises three polymerizing structures that have been studied for a long time, actin microfilaments, microtubules and intermediate filaments, plus more recently investigated dynamic assemblies like septins or the endocytic-sorting complex required for transport (ESCRT) complex. These filament-forming proteins control several cell functions through crosstalks with each other and with membranes. In this review, we report recent works that address how septins bind to membranes, and influence their shaping, organization, properties and functions, either by binding to them directly or indirectly through other cytoskeleton elements.

Advances in prognostic and therapeutic targets for hepatocellular carcinoma and intrahepatic cholangiocarcinoma: The hippo signaling pathway

Primary liver cancer is the sixth most frequently diagnosed cancer worldwide and the third leading cause of cancer-related death. The majority of the primary liver cancer cases are hepatocellular carcinoma and intrahepatic cholangiocarcinoma. Worldwide, there is an increasing incidence of primary liver cancer cases due to multiple risk factors ranging from parasites and viruses to metabolic diseases and lifestyles. Often, patients are diagnosed at advanced stages, depriving them of surgical curability benefits. Moreover, the efficacy of the available chemotherapeutics is limited in advanced stages. Furthermore, tumor metastases and recurrence make primary liver cancer management exceptionally challenging. Thus, exploring the molecular mechanisms for the development and progression of primary liver cancer is critical in improving diagnostic, treatment, prognostication, and surveillance modalities. These mechanisms facilitate the discovery of specific targets that are critical for novel and more efficient treatments. Consequently, the Hippo signaling pathway executing a pivotal role in organogenesis, hemostasis, and regeneration of tissues, regulates liver cells proliferation, and apoptosis. Cell polarity or adhesion molecules and cellular metabolic status are some of the biological activators of the pathway. Thus, understanding the mechanisms exhibited by the Hippo pathway is critical to the development of novel targeted therapies. This study reviews the advances in identifying therapeutic targets and prognostic markers of the Hippo pathway for primary liver cancer in the past six years.

HFE promotes mitotic cell division through recruitment of cytokinetic abscission machinery in hepatocellular carcinoma

HFE (Hemochromatosis) is a conventional iron level regulator and its loss of function due to gene mutations increases the risk of cancers including hepatocellular carcinoma (HCC). Likewise, studies focusing on HFE overexpression in cancers are all limited to linking up these events as a consequence of iron level deregulation. No study has explored any iron unrelated role of HFE in cancers. Here, we first reported HFE as an oncogene in HCC and its undescribed function on promoting abscission in cytokinesis during mitotic cell division, independent of its iron-regulating ability. Clinical analyses revealed HFE upregulation in tumors linking to large tumor size and poor prognosis. Functionally and mechanistically, HFE promoted cytokinetic abscission via facilitating ESCRT abscission machinery recruitment to the abscission site through signaling a novel HFE/ALK3/Smads/LIF/Hippo/YAP/YY1/KIF13A axis. Pharmacological blockage of HFE signaling axis impeded tumor phenotypes in vitro and in vivo. Our data on HFE-driven HCC unveiled a new mechanism utilized by cancer cells to propel rapid cell division. This study also laid the groundwork for tumor intolerable therapeutics development given the high cytokinetic dependency of cancer cells and their vulnerability to cytokinetic blockage.

TiO2 Nanotubes Promote Osteogenic Differentiation Through Regulation of Yap and Piezo1

Surface modification of titanium has been a hot topic to promote bone integration between implants and bone tissue. Titanium dioxide nanotubes fabricated on the surface of titanium by anodic oxidation have been a mature scheme that has shown to promote osteogenesis in vitro. However, mechanisms behind such a phenomenon remain elusive. In this study, we verified the enhanced osteogenesis of BMSCs on nanotopographic titanium in vitro and proved its effect in vivo by constructing a bone defect model in rats. In addition, the role of the mechanosensitive molecule Yap is studied in this research by the application of the Yap inhibitor verteporfin and knockdown/overexpression of Yap in MC3T3-E1 cells. Piezo1 is a mechanosensitive ion channel discovered in recent years and found to be elemental in bone metabolism. In our study, we preliminarily figured out the regulatory relationship between Yap and Piezo1 and proved Piezo1 as a downstream effector of Yap and nanotube-stimulated osteogenesis. In conclusion, this research proved that nanotopography promoted osteogenesis by increasing nuclear localization of Yap and activating the expression of Piezo1 downstream.

Role of Hippo signaling pathway in occurrence, development, and treatment of primary hepatocellular carcinoma

The Hippo signal transduction pathway, first discovered in drosophila, is a highly conserved signaling pathway that inhibits cell growth. Its core molecules include Hpo, Sav, Wts, Mats, and downstream effector factor YAP/TAZ. Corresponding homologous analogs in humans are STE20 protein-like kinase 1/2, Salvatore family 1, large tumor suppressor gene 1/2 kinase, and MOB kinase activator 1A/1B. Inactivation of this pathway promotes the survival, proliferation, invasive migration, and metastasis of cancer cells. This process can be seen in liver cancer, lung cancer, colorectal cancer, breast cancer, pancreatic cancer, melanoma, glioma, and other cancers, which can lead to the occurrence of resistance to chemotherapy, radiotherapy, or immunotherapy. This paper aims to review the role of the Hippo signaling pathway in the occurrence, development, and treatment of liver cancer, in order to provide reference for new targeted therapies for liver cancer.