CRISPR/Cas9-based Pten knock-out and Sleeping Beauty Transposon-mediated Nras knock-in induces hepatocellular carcinoma and hepatic lipid accumulation in mice

Oncogenic plasmid DNA and liver injury agent dictates liver cancer development in a mouse model

Primary liver cancer is an increasing problem worldwide and is associated with significant mortality. A popular method of modeling liver cancer in mice is plasmid hydrodynamic tail vein injection (HTVI). However, plasmid-HTVI models rarely recapitulate the chronic liver injury which precedes the development of most human liver cancer. We sought to investigate how liver injury using thioacetamide contributes to the pathogenesis and progression of liver cancer in two oncogenic plasmid-HTVI-induced mouse liver cancer models. Fourteen-week-old male mice received double-oncogene plasmid-HTVI (SB/AKT/c-Met and SB/AKT/NRas) and then twice-weekly intraperitoneal injections of thioacetamide for 6 weeks. Liver tissue was examined for histopathological changes, including fibrosis and steatosis. Further characterization of fibrosis and inflammation was performed with immunostaining and real-time quantitative PCR. RNA sequencing with pathway analysis was used to explore novel pathways altered in the cancer models. Hepatocellular and cholangiocellular tumors were observed in mice injected with double-oncogene plasmid-HTVI models (SB/AKT/c-Met and SB/AKT/NRas). Thioacetamide induced mild fibrosis and increased alpha smooth muscle actin-expressing cells. However, the combination of plasmids and thioacetamide did not significantly increase tumor size, but increased multiplicity of small neoplastic lesions. Cancer and/or liver injury up-regulated profibrotic and proinflammatory genes while metabolic pathway genes were mostly down-regulated. We conclude that the liver injury microenvironment can interact with liver cancer and alter its presentation. However, the effects on cancer development vary depending on the genetic drivers with differing active oncogenic pathways. Therefore, the choice of plasmid-HTVI model and injury agent may influence the extent to which injury promotes liver cancer development.

A review of the literature on the use of CRISPR/Cas9 gene therapy to treat hepatocellular carcinoma

Noncoding RNAs instruct the Cas9 nuclease to site-specifically cleave DNA in the CRISPR/Cas9 system. Despite the high incidence of hepatocellular carcinoma (HCC), the patient's outcome is poor. As a result of the emergence of therapeutic resistance in HCC patients, clinicians have faced difficulties in treating such tumor. In addition, CRISPR/Cas9 screens were used to identify genes that improve the clinical response of HCC patients. It is the objective of this article to summarize the current understanding of the use of the CRISPR/Cas9 system for the treatment of cancer, with a particular emphasis on HCC as part of the current state of knowledge. Thus, in order to locate recent developments in oncology research, we examined both the Scopus database and the PubMed database. The ability to selectively interfere with gene expression in combinatorial CRISPR/Cas9 screening can lead to the discovery of new effective HCC treatment regimens by combining clinically approved drugs. Drug resistance can be overcome with the help of the CRISPR/Cas9 system. HCC signature genes and resistance to treatment have been uncovered by genome-scale CRISPR activation screening, although this method is not without limitations. It has been extensively examined whether CRISPR can be used as a tool for disease research and gene therapy. CRISPR and its applications to tumor research, particularly in HCC, are examined in this study through a review of the literature.

USP35 promotes HCC development by stabilizing ABHD17C and activating the PI3K/AKT signaling pathway

S-palmitoylation is a reversible protein lipidation that controls the subcellular localization and function of targeted proteins, including oncogenes such as N-RAS. The depalmitoylation enzyme family ABHD17s can remove the S-palmitoylation from N-RAS to facilitate cancer development. We previously showed that ABHD17C has oncogenic roles in hepatocellular carcinoma (HCC) cells, and its mRNA stability is controlled by miR-145-5p. However, it is still unclear whether ABHD17C is regulated at the post-translational level. In the present study, we identified multiple ubiquitin-specific proteases (USPs) that can stabilize ABHD17C by inhibiting the ubiquitin-proteasome-mediated degradation. Among them, USP35 is the most potent stabilizer of ABHD17C. We found a positive correlation between the elevated expression levels of USP35 and ABHD17C, together with their association with increased PI3K/AKT pathway activity in HCCs. USP35 knockdown caused decreased ABHD17C protein level, impaired PI3K/AKT pathway, reduced proliferation, cell cycle arrest, increased apoptosis, and mitigated migration and invasion. USP35 can interact with and stabilize ABHD17C by inhibiting its ubiquitination. Overexpression of ABHD17C can rescue the defects caused by USP35 knockdown in HCC cells. In support of these in vitro observations, xenograft assay data also showed that USP35 deficiency repressed HCC development in vivo, characterized by reduced proliferation and disrupted PI3K/AKT signaling. Together, these findings demonstrate that USP35 may promote HCC development by stabilization of ABHD17C and activation of the PI3K/AKT pathway.

High-expressed PTPN1 promotes tumor proliferation signature in human hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a highly prevalent malignant tumor that is associated with substantial morbidity and mortality rates. Despite the progress made in diagnostic technology, the survival rate of HCC patients remains unsatisfactory due to the complex nature and extensive metastasis of the disease. Consequently, the discovery of new molecular targets is of great practical significance for the diagnosis and treatment of HCC. Protein tyrosine phosphatases (PTPs) play a crucial role in cell signal transduction by catalyzing the dephosphorylation of tyrosine residues in proteins. The present study has revealed that the upregulation of protein tyrosine phosphatase non-receptor type 1 (PTPN1) is a characteristic feature of HCC and is associated with a poor prognosis. Additionally, our investigation into the functional roles of PTPN1-regulated genes in HCC has demonstrated that alterations in PTPN1 expression disrupt normal cell cycle progression metabolism. Additionally, the capacity for proliferation and migration of HCC cells was notably diminished subsequent to PTPN1 silencing, resulting in the prevention of cell entry into the S phase from the G1 phase. Our investigation indicates that PTPN1 may facilitate the onset and progression of HCC by disrupting the cell cycle, thereby presenting a promising molecular target for the diagnosis and treatment of liver cancer.

Hydrodynamic Delivery: Characteristics, Applications, and Technological Advances

The principle of hydrodynamic delivery was initially used to develop a method for the delivery of plasmids into mouse hepatocytes through tail vein injection and has been expanded for use in the delivery of various biologically active materials to cells in various organs in a variety of animal species through systemic or local injection, resulting in significant advances in new applications and technological development. The development of regional hydrodynamic delivery directly supports successful gene delivery in large animals, including humans. This review summarizes the fundamentals of hydrodynamic delivery and the progress that has been made in its application. Recent progress in this field offers tantalizing prospects for the development of a new generation of technologies for broader application of hydrodynamic delivery.

Identification of circular RNA biomarkers for Pien Tze Huang treatment of CCl4‑induced liver fibrosis using RNA‑sequencing

Pien Tze Huang (PZH), a common hepatoprotective Traditional Chinese Medicine that has been found to be an effective treatment for carbon tetrachloride-induced hepatic damage, including liver fibrosis. Circular RNAs (circRNAs) serve a crucial role in regulating gene expression levels via circRNA/micro (mi)RNA/mRNA networks in several human diseases and biological processes. However, whether circRNAs are involved in the underlying mechanism of the therapeutic effects of PZH on liver fibrosis remains unclear. Therefore, the aim of the present study was to investigate these effects using circRNA expression profiles from PZH-treated fibrotic livers in model mice. A case-control study on >59,476 circRNAs from CCl₄-induced (control group, n=6) and PZH-treated (case group, n=6) mice was performed using circRNA sequencing in liver tissues. PZH treatment resulted in the differential expression of 91 circRNAs, including 58 upregulated and 33 downregulated circRNAs. Furthermore, the construction of competing endogenous networks also indicated that differentially expressed circRNAs acted as miRNA sponges. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis of miRNA targets demonstrated that PZH-affected circRNAs were mainly involved in biological processes such as ‘positive regulation of fibroblast proliferation’, ‘cellular response to interleukin-1’ and ‘regulation of DNA-templated transcription in response to stress’ and in a number of important pathways, such as ‘TNF signaling pathway’, ‘PI3K-Akt signaling pathway’, ‘IL-17 signaling pathway’ and ‘MAPK signaling pathway’. To further validate the bioinformatics data, reverse transcription–quantitative PCR was performed on seven miRNA targets in a human hepatic stellate LX-2 cell model. The results suggested that seven of the miRNAs exhibited regulatory patterns that were consistent with those of the transcriptome sequencing results. Kaplan-Meier survival analysis demonstrated that the expression levels of dihydrodiol dehydrogenase and solute carrier family 7, member 11 gene were significantly associated with patient survival, 269 patients with liver hepatocellular carcinoma from The Cancer Genome Atlas database. To the best of our knowledge, this was the first study to provide evidence that PZH affects circRNA expression levels, which may serve important roles in PZH-treated fibrotic liver through the regulation of functional gene expression. In conclusion, the present study provided new insights into the mechanism underlying the pathogenesis of liver fibrosis and identified potential novel, efficient, therapeutic targets against liver injury.

PLIN2 promotes HCC cells proliferation by inhibiting the degradation of HIF1α

PLIN2 has been found to be dysregulated in several human malignancies, which influences cancer progression. However, the roles of PLIN2 in regulating hepatocellular carcinoma (HCC) progression are still unclear. Here, we revealed that PLIN2 was frequently upregulated in HCC cells and tissues, and increased PLIN2 expression was associated with poor prognosis outcomes in HCC. In HCC cells, overexpressing PLIN2 promoted cell proliferation, PLIN2-deficiency inhibited cell vitality. Mechanistically, silencing of PLIN2 expression downregulated hypoxia inducible factor 1-α (HIF1α) expression and this downregulation in turn inhibited the targeting genes of HIF1α. Furthermore, we found that PLIN2 stabilized and retarded the degradation of the HIF1α through autophagy-lysosomal pathway by inhibiting AMPK/ULK1. Collectively, we clarified the carcinogenic role of PLIN2 in HCC and suggested a prognostic biomarker for diagnosis and clinical therapy in the future.

Biogenesis and Breakdown of Lipid Droplets in Pathological Conditions

Lipid droplets (LD) have long been considered as mere fat drops; however, LD have lately been revealed to be ubiquitous, dynamic and to be present in diverse organelles in which they have a wide range of key functions. Although incompletely understood, the biogenesis of eukaryotic LD initiates with the synthesis of neutral lipids (NL) by enzymes located in the endoplasmic reticulum (ER). The accumulation of NL leads to their segregation into nanometric nuclei which then grow into lenses between the ER leaflets as they are further filled with NL. The lipid composition and interfacial tensions of both ER and the lenses modulate their shape which, together with specific ER proteins, determine the proneness of LD to bud from the ER toward the cytoplasm. The most important function of LD is the buffering of energy. But far beyond this, LD are actively integrated into physiological processes, such as lipid metabolism, control of protein homeostasis, sequestration of toxic lipid metabolic intermediates, protection from stress, and proliferation of tumours. Besides, LD may serve as platforms for pathogen replication and defense. To accomplish these functions, from biogenesis to breakdown, eukaryotic LD have developed mechanisms to travel within the cytoplasm and to establish contact with other organelles. When nutrient deprivation occurs, LD undergo breakdown (lipolysis), which begins with the LD-associated members of the perilipins family PLIN2 and PLIN3 chaperone-mediated autophagy degradation (CMA), a specific type of autophagy that selectively degrades a subset of cytosolic proteins in lysosomes. Indeed, PLINs CMA degradation is a prerequisite for further true lipolysis, which occurs via cytosolic lipases or by lysosome luminal lipases when autophagosomes engulf portions of LD and target them to lysosomes. LD play a crucial role in several pathophysiological processes. Increased accumulation of LD in non-adipose cells is commonly observed in numerous infectious diseases caused by intracellular pathogens including viral, bacterial, and parasite infections, and is gradually recognized as a prominent characteristic in a variety of cancers. This review discusses current evidence related to the modulation of LD biogenesis and breakdown caused by intracellular pathogens and cancer.

MiR-421 promotes lipid metabolism by targeting PTEN via activating PI3K/AKT/mTOR pathway in non-small cell lung cancer

Aims: We aim to investigate the effects of miR-421 on lipid metabolism in non-small cell lung cancer (NSCLC). Methods: The miR-421 expression and PTEN mRNA level in tumor tissues, adjacent normal tissues, human lung epithelial cells and NSCLC cell lines were detected with reverse transcription quantitative real-time PCR. Results: MiR-421 was increased, and PTEN was reduced remarkably in tumor tissues and NSCLC cell lines. Down-regulated miR-421 suppressed lipid accumulation, cell proliferation, migration and invasion, whereas overexpression of miR-421 had the opposite effects. MiR-421 directly targeted PTEN and negatively regulated PTEN expression. MiR-421 activated PI3K/AKT/mTOR pathway through regulating PTEN. Conclusion: MiR-421 promotes lipid metabolism through targeting PTEN via PI3K/AKT/mTOR pathway activation in NSCLC, indicating that miR-421 can be a latent therapeutic target for NSCLC.

Insertion Specificity of the hATx-6 Transposase of Hydra magnipapillata

Transposable elements (TE) are mobile genetic elements, present in all domains of life. They commonly encode a single transposase enzyme, that performs the excision and reintegration reactions, and these enzymes have been used in mutagenesis and creation of next-generation sequencing libraries. All transposases have some bias in the DNA sequence they bind to when reintegrating the TE DNA. We sought to identify a transposase that showed minimal sequence bias and could be produced recombinantly, using information from the literature and a novel bioinformatic analysis, resulting in the selection of the hATx-6 transposase from Hydra vulgaris (aka Hydra magnipapillata) for further study. This transposase was tested and shown to be active both in vitro and in vivo, and we were able to demonstrate very low sequence bias in its integration preference. This transposase could be an excellent candidate for use in biotechnology, such as the creation of next-generation sequencing libraries.

The power and the promise of CRISPR/Cas9 genome editing for clinical application with gene therapy

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Due to its high accuracy and efficiency, CRISPR/Cas9 techniques may provide a great chance to treat some gene-related diseases.

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Researchers used the CRISPR/Cas9 technique to cure or alleviate cancers through different approaches, such as gene therapy and immune therapy.

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The treatment of ocular diseases by Cas9 has entered into clinical phases.

Background

Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) is derived from the bacterial innate immune system and engineered as a robust gene-editing tool. Due to the higher specificity and efficiency of CRISPR/Cas9, it has been widely applied to many genetic and non-genetic disease, including cancers, genetic hemolytic diseases, acquired immunodeficiency syndrome, cardiovascular diseases, ocular diseases, and neurodegenerative diseases, and some X-linked diseases. Furthermore, in terms of the therapeutic strategy of cancers, many researchers used the CRISPR/Cas9 technique to cure or alleviate cancers through different approaches, such as gene therapy and immune therapy.

Aim of Review

Here, we conclude the recent application and clinical trials of CRISPR/Cas9 in non-cancerous diseases and cancers and pointed out some of the problems to be solved.

Key Scientific Concepts of Review

CRISPR/Cas9, derived from the microbial innate immune system, is developed as a robust gene-editing tool and has been applied widely. Due to its high accuracy and efficiency, CRISPR/Cas9 techniques may provide a great chance to treat some gene-related diseases by disrupting, inserting, correcting, replacing, or blocking genes for clinical application with gene therapy.

Phosphatase and tensin homolog (PTEN) suppresses triacylglycerol accumulation and monounsaturated fatty acid synthesis in goat mammary epithelial cells

Phosphatase and tensin homolog (PTEN) is a well-known tumor suppressor in nonruminants and regulates various cellular processes including growth through dephosphorylation of phosphoinositide substrates. Although studies with bovine mammary tissue suggested a role for PTEN during lactation, its potential role in lipid metabolism remains unknown. Objectives of the present study were to determine PTEN abundance in goat mammary tissue at 2 stages of lactation (n = 6 Xinong Saanen dairy goats per stage), and to use gene-silencing and adenoviral transfections in vitro with isolated goat mammary epithelial cells (GMEC) to evaluate the role of PTEN abundance of lipid metabolism-related genes. Abundance of PTEN decreased by 51.5% at peak lactation compared with the dry period. The PTEN was overexpressed in isolated GMEC through adenoviral transfection using an adenovirus system with Ad-GFP (recombinant adenovirus of green fluorescent protein) as control, and silenced via targeted small interfering RNA (siRNA) transfection with a scrambled small interfering RNA as a negative control. Cell culture was performed for 48 h before RNA extraction, triacylglycerol (TAG) analysis, and fatty acid analysis. Overexpression of PTEN downregulated abundance of acetyl-coenzyme A carboxylase α (ACACA), fatty acid synthase (FASN), sterol regulatory element binding transcription factor1 (SREBF1), stearoyl-coenzyme A desaturase 1 (SCD1), diacylglycerol acytransferase 1 (DGAT1), 1-acylglycerol-3-phosphate O-acyltransferase 6 (AGPAT6) coupled with an increase in patatin-like-phospholipase domain containing 2 (PNPLA2), hormone-sensitive lipase (LIPE), and carnitine palmitoyltransferase 1 β (CPT1B). Furthermore, overexpressing PTEN in vitro resulted in a significant decrease in TAG concentration and concentration of C16:1. In contrast, interference of PTEN led to an opposite effect on lipid metabolism in GMEC. These changes suggested a shift from lipogenesis and esterification to lipolysis and fatty acid oxidation. Collectively, PTEN seems to play a role in monounsaturated fatty acids synthesis and lipid accumulation in GMEC.

Lipid droplet and its implication in cancer progression

Lipid droplets (LDs) are a kind of organelle that is commonly found in eukaryotic cells to store lipids, which encompass a hydrophobic core composed of a single layer of phospholipids and neutral lipids (mainly including triacylglycerol (TAG) and cholesterol ester (CE)) as well as a small amount of proteins. LD accumulation is gradually recognized as a prominent characteristic in a variety of cancers and attracts increasing attention on this field. In this article, we not only summarize the composition, synthesis and decomposition of LD, but also highlight its role in carcinogenesis and malignant development of cancers.

Identification and analysis of circRNA-miRNA-mRNA regulatory network in hepatocellular carcinoma

This study was to identify important circRNA-miRNA-mRNA (ceRNAs) regulatory mechanisms in hepatocellular carcinoma (HCC). The circRNA dataset GSE97332 and miRNA dataset GSE57555 were used for analyses. Functional enrichment analysis for miRNA and target gene was conducted using cluster Profiler. Survival analysis was conducted through R package Survival. The ceRNAs and drug-gene interaction networks were constructed. The ceRNAs network contained five miRNAs including hsa-miR-25-3p, hsa-miR-3692-5p, hsa-miR-4270, hsa-miR-331-3p, and hsa-miR-125a-3p. Among the network, hsa-miR-25-3p targeted the most genes, hsa-miR-3692-5p and hsa-miR-4270 were targeted by more circRNAs than other miRNAs, hsa-circ-0034326 and hsa-circ-0011950 interacted with three miRNAs. Furthermore, target genes, including NRAS, ITGA5, SLC7A1, SEC14L2, SLC12A5, and SMAD2 were obtained in drug-gene interaction network. Survival analysis showed NRAS, ITGA5, SLC7A1, SEC14L2, SLC12A5, and SMAD2 were significantly associated with prognosis of HCC. NRAS, ITGA5, and SMAD2 were significantly enriched in proteoglycans in cancer. Moreover, hsa-circ-0034326 and hsa-circ-0011950 might function as ceRNAs to play key roles in HCC. Furthermore, miR-25-3p, miR-3692-5p, and miR-4270 might be significant for HCC development. NRAS, ITGA5, SEC14L2, SLC12A5, and SMAD2 might be prognostic factors for HCC patients via proteoglycans in cancer pathway. Taken together, the findings will provide novel insight into pathogenesis, selection of therapeutic targets and prognostic factors for HCC.

Delivery Approaches for Therapeutic Genome Editing and Challenges

Impressive therapeutic advances have been possible through the advent of zinc-finger nucleases and transcription activator-like effector nucleases. However, discovery of the more efficient and highly tailorable clustered regularly interspaced short palindromic repeats (CRISPR) and associated proteins (Cas9) has provided unprecedented gene-editing capabilities for treatment of various inherited and acquired diseases. Despite recent clinical trials, a major barrier for therapeutic gene editing is the absence of safe and effective methods for local and systemic delivery of gene-editing reagents. In this review, we elaborate on the challenges and provide practical considerations for improving gene editing. Specifically, we highlight issues associated with delivery of gene-editing tools into clinically relevant cells.

CRISPR/Cas gene therapy

Clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated enzyme (Cas) is a naturally occurring genome editing tool adopted from the prokaryotic adaptive immune defense system. Currently, CRISPR/Cas9-based genome editing has been becoming one of the most promising tools for treating human genetic diseases, including cardiovascular diseases, neuro-disorders, and cancers. As the quick modification of the CRISPR/Cas9 system, including delivery system, CRISPR/Cas9-based gene therapy has been extensively studied in preclinic and clinic treatments. CRISPR/Cas genome editing is also a robust tool to create animal genetic models for studying and treating human genetic disorders, particularly diseases associated with point mutations. However, significant challenges also remain before CRISPR/Cas technology can be routinely employed in the clinic for treating different genetic diseases, which include toxicity and immune response of treated cells to CRISPR/Cas component, highly throughput delivery method, and potential off-target impact. The off-target effect is one of the major concerns for CRISPR/Cas9 gene therapy, more research should be focused on limiting this impact by designing high specific gRNAs and using high specificity of Cas enzymes. Modifying the CRISPR/Cas9 delivery method not only targets a specific tissue/cell but also potentially limits the off-target impact.

Knockdown of phosphatase and tensin homolog (PTEN) inhibits fatty acid oxidation and reduces very low density lipoprotein assembly and secretion in calf hepatocytes

Dairy cows with fatty liver exhibit hepatic lipid accumulation and disturbances in fatty acid oxidation and lipid transport. Phosphatase and tensin homolog (PTEN), a lipid phosphatase, regulates intrahepatic fatty acid oxidation and lipid transport in mice. Whether PTEN play a role in fatty acid oxidation and very low density lipoprotein (VLDL) assembly in calf hepatocytes are unknown. Hepatocytes isolated from 3 healthy female Holstein calves (1 d old, 30-40 kg) were infected with empty adenovirus with green fluorescent protein for 48 h (Ad-GFP group) or infected with PTEN knockdown adenovirus for 48 h (Ad-shPTEN group), or cultured in RPMI-1640 without Ad-shPTEN or Ad-GFP (control group). Compared with the Ad-GFP group, PTEN knockdown decreased mRNA and protein abundance and the activity of fatty acid oxidation-related molecules, including acyl-coA synthetase long-chain 1, carnitine palmitoyltransferase 1, carnitine palmitoyltransferase 2, and 3-hydroxy acyl-coA dehydrogenase. Furthermore, PTEN knockdown decreased mRNA and protein abundance of VLDL assembly-related molecules, including apolipoprotein B100, apolipoprotein E, microsomal triglyceride transfer protein, and low density lipoprotein receptor. Importantly, PTEN knockdown promoted triglyceride accumulation in hepatocytes and reduced the VLDL content in culture medium. A subsequent study was conducted on the following 4 groups: cells infected with Ad-GFP for 48 h and then treated with 2% BSA for another 24 h (Ad-GFP + BSA); cells infected with Ad-GFP for 48 h and then treated with 1.2 mM free fatty acids (FFA) and 2% BSA for another 24 h (Ad-GFP + 1.2 mM FFA); cells infected with Ad-shPTEN for 48 h and then treated with 2% BSA for another 24 h (Ad-shPTEN + BSA); cells infected with Ad-shPTEN for 48 h and then treated with 1.2 mM FFA and 2% BSA for another 24 h (Ad-shPTEN + 1.2 mM FFA). Compared with Ad-GFP + BSA, the abundances of PTEN and of fatty acid oxidation- and VLDL assembly-related proteins were lower in the Ad-GFP + 1.2 mM FFA group. Importantly, PTEN knockdown heightened the increase in triglyceride accumulation of hepatocytes and the decrease in VLDL content in culture medium induced by FFA. Overall, these in vitro data indicate that FFA inhibits PTEN expression, leading to triglyceride accumulation and the inhibition of VLDL assembly in calf hepatocytes. These findings suggest that PTEN may be a potential therapeutic target for FFA-induced hepatic steatosis in dairy cows.

Overexpression of HGF/MET axis along with p53 inhibition induces de novo glioma formation in mice

Background

Aberrant MET receptor tyrosine kinase (RTK) activation leads to invasive tumor growth in different types of cancer. Overexpression of MET and its ligand hepatocyte growth factor (HGF) occurs more frequently in glioblastoma (GBM) than in low-grade gliomas. Although we have shown previously that HGF-autocrine activation predicts sensitivity to MET tyrosine kinase inhibitors (TKIs) in GBM, whether it initiates tumorigenesis remains elusive.

Methods

Using a well-established Sleeping Beauty (SB) transposon strategy, we injected human HGF and MET cDNA together with a short hairpin siRNA against Trp53 (SB-hHgf.Met.ShP53) into the lateral ventricle of neonatal mice to induce spontaneous glioma initiation and characterized the tumors with H&E and immunohistochemistry analysis. Glioma sphere cells also were isolated for measuring the sensitivity to specific MET TKIs.

Results

Mixed injection of SB-hHgf.Met.ShP53 plasmids induced de novo glioma formation with invasive tumor growth accompanied by HGF and MET overexpression. While glioma stem cells (GSCs) are considered as the tumor-initiating cells in GBM, both SB-hHgf.Met.ShP53 tumor sections and glioma spheres harvested from these tumors expressed GSC markers nestin, GFAP, and Sox 2. Moreover, specific MET TKIs significantly inhibited tumor spheres' proliferation and MET/MAPK/AKT signaling.

Conclusions

Overexpression of the HGF/MET axis along with p53 attenuation may transform neural stem cells into GSCs, resulting in GBM formation in mice. These tumors are primarily driven by the MET RTK pathway activation and are sensitive to MET TKIs. The SB-hHgf.Met.ShP53 spontaneous mouse glioma model provides a useful tool for studying GBM tumor biology and MET-targeting therapeutics.

Diet induces hepatocyte protection in fatty liver disease via modulation of PTEN signaling

Fatty liver disease (FLD) is characterized by accumulation of excess fat in the liver. The underlying molecular mechanism associated with the progression of the disease has been in elusive. Hepatocellular demise due to increased oxidative stress resulting in an inflammatory response may be a key feature in FLD. Recent advances in molecular biology have led to an improved understanding of the molecular pathogenesis, suggesting a critical association between the PI3K/AKT/PTEN signaling pathway and FLD. In particular, PTEN has been associated with regulating the pathogenesis of hepatocyte degeneration. Given the function of mitochondria in reactive oxygen species (ROS) generation and the initiation of oxidative stress, the mitochondrial antioxidant network is of interest. It is vital to balance the activity of intracellular key molecules to maintain a healthy liver. Consequently, onset of FLD may be delayed using dietary protective agents that alter PTEN signaling and reduce ROS levels. The advancement of research on dietary regulation with a focus on modulatory roles in ROS generation and PTEN associated signaling is summarized in the current study, supporting further preventive and therapeutic exploration.

Using CRISPR/Cas9 to model human liver disease

CRISPR/Cas9 gene editing has revolutionised biomedical research. The ease of design has allowed many groups to apply this technology for disease modelling in animals. While the mouse remains the most commonly used organism for embryonic editing, CRISPR is now increasingly performed with high efficiency in other species. The liver is also amenable to somatic genome editing, and some delivery methods already allow for efficient editing in the whole liver. In this review, we describe CRISPR-edited animals developed for modelling a broad range of human liver disorders, such as acquired and inherited hepatic metabolic diseases and liver cancers. CRISPR has greatly expanded the repertoire of animal models available for the study of human liver disease, advancing our understanding of their pathophysiology and providing new opportunities to develop novel therapeutic approaches.

Mito-Nuclear Communication in Hepatocellular Carcinoma Metabolic Rewiring

As the main metabolic and detoxification organ, the liver constantly adapts its activity to fulfill the energy requirements of the whole body. Despite the remarkable adaptive capacity of the liver, prolonged exposure to noxious stimuli such as alcohol, viruses and metabolic disorders results in the development of chronic liver disease that can progress to hepatocellular carcinoma (HCC), which is currently the second leading cause of cancer-related death worldwide. Metabolic rewiring is a common feature of cancers, including HCC. Altered mito-nuclear communication is emerging as a driving force in the metabolic reprogramming of cancer cells, affecting all aspects of cancer biology from neoplastic transformation to acquired drug resistance. Here, we explore relevant aspects (and discuss recent findings) of mito-nuclear crosstalk in the metabolic reprogramming of hepatocellular carcinoma.

CRISPR/Cas9: a powerful tool for identification of new targets for cancer treatment

Clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR associated nuclease 9 (Cas9), as a powerful genome-editing tool, has revolutionized genetic engineering. It is widely used to investigate the molecular basis of different cancer types. In this review, we present an overview of recent studies in which CRISPR/Cas9 has been used for the identification of potential molecular targets. Based on the collected data, we suggest here that CRISPR/Cas9 is an effective system to distinguish between mutant and wild-type alleles in cancer. We show that several new potential therapeutic targets, such as CD38, CXCR2, MASTL, and RBX2, as well as several noncoding (nc)RNAs have been identified using CRISPR/Cas9 technology. We also discuss the obstacles and challenges that we face for using CRISPR/Cas9 as a therapeutic.

Potentials of CRISPR in liver research and therapy

The CRISPR technology is rapidly transforming the field of liver research by its versatility and easy use. In vivo gene editing of hepatocytes in adult mice can be achieved using a broad toolbox for both fundamental research and development of therapeutic strategies for future clinical applications. Recent studies showed that CRISPR has a real potential to treat hereditary liver diseases as well as virally induced pathologies. This short review recapitulates very recent advancements regarding the use of CRISPR in liver research and therapy.

Podocyte-specific knockin of PTEN protects kidney from hyperglycemia

Phosphatase and tensin homolog deleted on chromosome 10 (PTEN) has proven to be downregulated in podocytes challenged with high glucose (HG), and knockout of PTEN in podocytes aggravated the progression of diabetic kidney disease (DKD). However, whether podocyte-specific knockin of PTEN protects the kidney against hyperglycemia in vivo remains unknown. The inducible podocyte-specific PTEN knockin (PPKI) mice were generated by crossing newly created transgenic loxP-stop- loxP-PTEN mice with podocin-iCreER^T2 mice. Diabetes mellitus was induced in mice by intraperitoneal injection of streptozotocin at a dose of 150 mg/kg. In vitro, small interfering RNA and adenovirus interference were used to observe the role of PTEN in HG-treated podocytes. Our data demonstrated that PTEN was markedly reduced in the podocytes of patients with DKD and focal segmental glomerulosclerosis, as well as in those of db/db mice. Interestingly, podocyte-specific knockin of PTEN significantly alleviated albuminuria, mesangial matrix expansion, effacement of podocyte foot processes, and incrassation of glomerular basement membrane in diabetic PPKI mice compared with wild-type diabetic mice, whereas no alteration was observed in the level of blood glucose. The potential renal protection of overexpressed PTEN in podocytes was partly attributed with an improvement in autophagy and motility and the inhibition of apoptosis. Our results showed that podocyte-specific knockin of PTEN protected the kidney against hyperglycemia in vivo , suggesting that targeting PTEN might be a novel and promising therapeutic strategy against DKD.