Integrated Genomic Comparison of Mouse Models Reveals Their Clinical Resemblance to Human Liver Cancer

Integrated Exploration of Epigenetic Dysregulation Reveals a Stemness/EMT Subtype and MMP12 Linked to the Progression and Prognosis in Hepatocellular Carcinoma

Epigenetic dysregulation drives aberrant transcriptional programs playing a critical role in hepatocellular carcinoma (HCC), which may provide novel insights into the heterogeneity of HCC. This study performed an integrated exploration on the epigenetic dysregulation of miRNA and methylation. We discovered and validated three patterns endowed with gene-related transcriptional traits and clinical outcomes. Specially, a stemness/epithelial-mesenchymal transition (EMT) subtype was featured by immune exhaustion and the worst prognosis. Besides, MMP12, a characteristic gene, was highly expressed in the stemness/EMT subtype, which was verified as a pivotal regulator linked to the unfavorable prognosis and further proven to promote tumor proliferation, invasion, and metastasis in vitro experiments. Proteomic analysis by mass spectrometry sequencing also indicated that the overexpression of MMP12 was significantly associated with cell proliferation and adhesion. Taken together, this study unveils innovative insights into epigenetic dysregulation and identifies a stemness/EMT subtype-specific gene, MMP12, correlated with the progression and prognosis of HCC.

Proteomic analysis of DEN and CCl4-induced hepatocellular carcinoma mouse model

Hepatocellular carcinoma (HCC) seriously threatens human health, mostly developed from liver fibrosis or cirrhosis. Since diethylnitrosamine (DEN) and carbon tetrachloride (CCl4)-induced HCC mouse model almost recapitulates the characteristic of HCC with fibrosis and inflammation, it is taken as an essential tool to investigate the pathogenesis of HCC. However, a comprehensive understanding of the protein expression profile of this model is little. In this study, we performed proteomic analysis of this model to elucidate its proteomic characteristics. Compared with normal liver tissues, 432 differentially expressed proteins (DEPs) were identified in tumor tissues, among which 365 were up-regulated and 67 were down-regulated. Through Gene Ontology (GO) analysis, Ingenuity Pathway Analysis (IPA), protein-protein interaction networks (PPI) analysis and Gene-set enrichment analysis (GSEA) analysis of DEPs, we identified two distinguishing features of DEN and CCl4-induced HCC mouse model in protein expression, the upregulation of actin cytoskeleton and branched-chain amino acids metabolic reprogramming. In addition, matching DEPs from the mouse model to homologous proteins in the human HCC cohort revealed that the DEN and CCl4-induced HCC mouse model was relatively similar to the subtype of HCC with poor prognosis. Finally, combining clinical information from the HCC cohort, we screened seven proteins with prognostic significance, SMAD2, PTPN1, PCNA, MTHFD1L, MBOAT7, FABP5, and AGRN. Overall, we provided proteomic data of the DEN and CCl4-induced HCC mouse model and highlighted the important proteins and pathways in it, contributing to the rational application of this model in HCC research.

Relevance of Carcinogen-Induced Preclinical Cancer Models

Chemical agents can cause cancer in animals by damaging their DNA, mutating their genes, and modifying their epigenetic signatures. Carcinogen-induced preclinical cancer models are useful for understanding carcinogen-induced human cancers, as they can reproduce the diversity and complexity of tumor types, as well as the interactions with the host environment. However, these models also have some drawbacks that limit their applicability and validity. For instance, some chemicals may be more effective or toxic in animals than in humans, and the tumors may differ in their genetics and phenotypes. Some chemicals may also affect normal cells and tissues, such as by causing oxidative stress, inflammation, and cell death, which may alter the tumor behavior and response to therapy. Furthermore, some chemicals may have variable effects depending on the exposure conditions, such as dose, route, and duration, as well as the animal characteristics, such as genetics and hormones. Therefore, these models should be carefully chosen, validated, and standardized, and the results should be cautiously interpreted and compared with other models. This review covers the main features of chemically induced cancer models, such as genetic and epigenetic changes, tumor environment, angiogenesis, invasion and metastasis, and immune response. We also address the pros and cons of these models and the current and future challenges for their improvement. This review offers a comprehensive overview of the state of the art of carcinogen-induced cancer models and provides new perspectives for cancer research.

CRISPR/Cas9-based application for cancer therapy: Challenges and solutions for non-viral delivery

CRISPR/Cas9 genome editing is a promising therapeutic technique, which makes precise and rapid gene editing technology possible on account of its high sensitivity and efficiency. CRISPR/Cas9 system has been proved to able to effectively disrupt and modify genes, which shows great potential for cancer treatment. Current researches proves that virus vectors are capable of effectively delivering the CRISPR/Cas9 system, but immunogenicity and carcinogenicity caused by virus transmission still trigger serious consequences. Therefore, the greatest challenge of CRISPR/Cas9 for cancer therapy lies on how to deliver it to the target tumor site safely and effectively. Non-viral delivery systems with specific targeting, high loading capacity, and low immune toxicity are more suitable than viral vectors, which limited by uncontrollable side effects. Their medical advances and applications have been widely concerned. Herein, we present the molecule mechanism and different construction strategies of CRISPR/Cas9 system for editing genes at the beginning of this research. Subsequently, several common CRISPR/Cas9 non-viral deliveries for cancer treatment are introduced. Lastly, based on the main factors limiting the delivery efficiency of non-viral vectors proposed in the existing researches and literature, we summarize and discuss the main methods to solve these limitations in the existing tumor treatment system, aiming to introduce further optimization and innovation of the CRISPR/Cas9 non-viral delivery system suitable for cancer treatment.

Nuclear Expression of Pygo2 Correlates with Poorly Differentiated State Involving c-Myc, PCNA and Bcl9 in Myanmar Hepatocellular Carcinoma

In Myanmar, hepatocellular carcinoma (HCC) is commonly seen in young adult and associated with poor prognosis, while the molecular mechanisms that characterize HCC in Myanmar are unknown. As co-activation of Wnt/β-catenin signaling and c-Myc (Myc) are reported to associate with malignancy of HCC, we immunohistochemically investigated the expression of Pygo2 and Bcl9, the co-activators of the Wnt/β-catenin signaling, Myc and PCNA in 60 cases of Myanmar HCC. Pygo2 expression was confirmed by in situ hybridization. The signal intensity was measured by image analyzer and then statistically analyzed. As a result, the expression of Pygo2 was significantly higher in HCC compared to normal liver tissue and the nuclear signal was the most intense in poorly differentiated HCC. Cytoplasmic Bcl9 was expressed in the normal liver tissue but decreased in HCC with the progression of histopathological grade. Myc was significantly higher in poorly differentiated HCC, whereas PCNA labeling index increased with the progression of histopathological grade. Nuclear Pygo2 showed strong correlation with nuclear Myc (P < 0.01) and PCNA (P < 0.001), and inversely correlated with cytoplasmic Bcl9 (P < 0.01). Our results suggested Wnt/β-catenin and Myc signaling is commonly activated in Myanmar HCC and that the correlative upregulation of nuclear Pygo2 and Myc characterizes the malignant features of HCC in Myanmar.

In Vivo and In Vitro Models of Hepatocellular Carcinoma: Current Strategies for Translational Modeling

Hepatocellular carcinoma (HCC) is the sixth most common cancer worldwide and the third leading cause of cancer-related death globally. HCC is a complex multistep disease and usually emerges in the setting of chronic liver diseases. The molecular pathogenesis of HCC varies according to the etiology, mainly caused by chronic hepatitis B and C virus infections, chronic alcohol consumption, aflatoxin-contaminated food, and non-alcoholic fatty liver disease associated with metabolic syndrome or diabetes mellitus. The establishment of HCC models has become essential for both basic and translational research to improve our understanding of the pathophysiology and unravel new molecular drivers of this disease. The ideal model should recapitulate key events observed during hepatocarcinogenesis and HCC progression in view of establishing effective diagnostic and therapeutic strategies to be translated into clinical practice. Despite considerable efforts currently devoted to liver cancer research, only a few anti-HCC drugs are available, and patient prognosis and survival are still poor. The present paper provides a state-of-the-art overview of in vivo and in vitro models used for translational modeling of HCC with a specific focus on their key molecular hallmarks.

Transcriptomic analysis links hepatocellular carcinoma (HCC) in HZE ion irradiated mice to a human HCC subtype with favorable outcomes

High-charge, high-energy ion particle (HZE) radiations are extraterrestrial in origin and characterized by high linear energy transfer (high-LET), which causes more severe cell damage than low-LET radiations like γ-rays or photons. High-LET radiation poses potential cancer risks for astronauts on deep space missions, but the studies of its carcinogenic effects have relied heavily on animal models. It remains uncertain whether such data are applicable to human disease. Here, we used genomics approaches to directly compare high-LET radiation-induced, low-LET radiation-induced and spontaneous hepatocellular carcinoma (HCC) in mice with a human HCC cohort from The Cancer Genome Atlas (TCGA). We identified common molecular pathways between mouse and human HCC and discovered a subset of orthologous genes (mR-HCC) that associated high-LET radiation-induced mouse HCC with a subgroup (mrHCC2) of the TCGA cohort. The mrHCC2 TCGA cohort was more enriched with tumor-suppressing immune cells and showed a better prognostic outcome than other patient subgroups.

The tumor suppressor role of salvador family WW domain-containing protein 1 (SAV1): one of the key pieces of the tumor puzzle

PURPOSE

In the complex tumor scenario, understanding the function of proteins with protumor or antitumor roles is essential to support advances in the cancer clinical area. Among them, the salvador family WW domain-containing protein 1 (SAV1) is highlighted. This protein plays a fundamental role in the tumor suppressor face of the Hippo pathway, which are responsible for controlling cell proliferation, organ size, development and tissue homeostasis. However, the functional dysregulation of this pathway may contribute to tumorigenesis and tumor progression. As SAV1 is a tumor suppressor scaffold protein, we explored the functions performed by SAV1 with its partners, the regulation of its expression, and its antitumor role in various types of cancer.

METHODS

We selected and analyzed 80 original articles and reviews from Pubmed that focuses on the study of SAV1 in cancer.

RESULTS

SAV1 interacts with several proteins, has different functions and acts as tumor suppressor by other mechanisms besides Hippo pathway. SAV1 expression regulation seems to occur by microRNAs and rarely by mutation or promoter methylation. It is downregulated in different types of cancer, which leads to cancer promotion and progression and is associated with poor prognosis. In vivo models have shown that the loss of SAV1 contributes to tumorigenesis.

CONCLUSION

SAV1 plays a relevant role as tumor suppressor in several types of cancer, highlighting SAV1 and the Hippo pathway's importance to cancer. Thus, encouraging further studies to include the SAV1 as a molecular key piece in cancer biology and in clinical approaches to cancer.

Cooperation Between MYC and β-Catenin in Liver Tumorigenesis Requires Yap/Taz

BACKGROUND AND AIMS

Activation of MYC and catenin beta-1 (CTNNB1, encoding β-catenin) can co-occur in liver cancer, but how these oncogenes cooperate in tumorigenesis remains unclear.

APPROACH AND RESULTS

We generated a mouse model allowing conditional activation of MYC and WNT/β-catenin signaling (through either β-catenin activation or loss of APC - adenomatous polyposis coli) upon expression of CRE recombinase in the liver and monitored their effects on hepatocyte proliferation, apoptosis, gene expression profiles, and tumorigenesis. Activation of WNT/β-catenin signaling strongly accelerated MYC-driven carcinogenesis in the liver. Both pathways also cooperated in promoting cellular transformation in vitro, demonstrating their cell-autonomous action. Short-term induction of MYC and β-catenin in hepatocytes, followed by RNA-sequencing profiling, allowed the identification of a "Myc/β-catenin signature," composed of a discrete set of Myc-activated genes whose expression increased in the presence of active β-catenin. Notably, this signature enriched for targets of Yes-associated protein (Yap) and transcriptional coactivator with PDZ-binding motif (Taz), two transcriptional coactivators known to be activated by WNT/β-catenin signaling and to cooperate with MYC in mitogenic activation and liver transformation. Consistent with these regulatory connections, Yap/Taz accumulated upon Myc/β-catenin activation and were required not only for the ensuing proliferative response, but also for tumor cell growth and survival. Finally, the Myc/β-catenin signature was enriched in a subset of human hepatocellular carcinomas characterized by comparatively poor prognosis.

CONCLUSIONS

Myc and β-catenin show a strong cooperative action in liver carcinogenesis, with Yap and Taz serving as mediators of this effect. These findings warrant efforts toward therapeutic targeting of Yap/Taz in aggressive liver tumors marked by elevated Myc/β-catenin activity.

Correction of the tumor suppressor Salvador homolog-1 deficiency in tumors by lycorine as a new strategy in lung cancer therapy

Salvador homolog-1 (SAV1) is a tumor suppressor required for activation of the tumor-suppressive Hippo pathway and inhibition of tumorigenesis. SAV1 is defective in several cancer types. SAV1 deficiency in cells promotes tumorigenesis and cancer metastasis, and is closely associated with poor prognosis for cancer patients. However, investigation of therapeutic strategies to target SAV1 deficiency in cancer is lacking. Here we found that the small molecule lycorine notably increased SAV1 levels in lung cancer cells by inhibiting SAV1 degradation via a ubiquitin-lysosome system, and inducing phosphorylation and activation of the SAV1-interacting protein mammalian Ste20-like 1 (MST1). MST1 activation then caused phosphorylation, ubiquitination, and degradation of the oncogenic Yes-associated protein (YAP), therefore inhibiting YAP-activated transcription of oncogenic genes and tumorigenic AKT and NF-κB signal pathways. Strikingly, treating tumor-bearing xenograft mice with lycorine increased SAV1 levels, and strongly inhibited tumor growth, vasculogenic mimicry, and metastasis. This work indicates that correcting SAV1 deficiency in lung cancer cells is a new strategy for cancer therapy. Our findings provide a new platform for developing novel cancer therapeutics.

Genomic Perspective on Mouse Liver Cancer Models

Selecting the most appropriate mouse model that best recapitulates human hepatocellular carcinoma (HCC) allows translation of preclinical mouse studies into clinical studies. In the era of cancer genomics, comprehensive and integrative analysis of the human HCC genome has allowed categorization of HCC according to molecular subtypes. Despite the variety of mouse models that are available for preclinical research, there is a lack of evidence for mouse models that closely resemble human HCC. Therefore, it is necessary to identify the accurate mouse models that represent human HCC based on molecular subtype as well as histologic aggressiveness. In this review, we summarize the mouse models integrated with human HCC genomic data to provide information regarding the models that recapitulates the distinct aspect of HCC biology and prognosis based on molecular subtypes.

Hepatocellular carcinoma: Therapeutic advances in signaling, epigenetic and immune targets

Hepatocellular carcinoma (HCC) remains a global medical burden with rising incidence due to chronic viral hepatitis and non-alcoholic fatty liver diseases. Treatment of advanced disease stages is still unsatisfying. Besides first and second generation tyrosine kinase inhibitors, immune checkpoint inhibitors have become central for the treatment of HCC. New modalities like epigenetic therapy using histone deacetylase inhibitors (HDACi) and cell therapy approaches with chimeric antigen receptor T cells (CAR-T cells) are currently under investigation in clinical trials. Development of such novel drugs is closely linked to the availability and improvement of novel preclinical and animal models and the identification of predictive biomarkers. The current status of treatment options for advanced HCC, emerging novel therapeutic approaches and different preclinical models for HCC drug discovery and development are reviewed here.