Hypoxia inducible factors in liver disease and hepatocellular carcinoma: current understanding and future directions

SerpinB3: A Multifaceted Player in Health and Disease-Review and Future Perspectives

SerpinB3, a member of the serine-protease inhibitor family, has emerged as a crucial player in various physiological and pathological processes. Initially identified as an oncogenic factor in squamous cell carcinomas, SerpinB3's intricate involvement extends from fibrosis progression and cancer to cell protection in acute oxidative stress conditions. This review explores the multifaceted roles of SerpinB3, focusing on its implications in fibrosis, metabolic syndrome, carcinogenesis and immune system impairment. Furthermore, its involvement in tissue protection from oxidative stress and wound healing underscores its potential as diagnostic and therapeutic tool. Recent studies have described the therapeutic potential of targeting SerpinB3 through its upstream regulators, offering novel strategies for cancer treatment development. Overall, this review underscores the importance of further research to fully elucidate the mechanisms of action of SerpinB3 and to exploit its therapeutic potential across various medical conditions.

Harnessing CD8+ T cell dynamics in hepatitis B virus-associated liver diseases: Insights, therapies and future directions

Hepatitis B virus (HBV) infection playsa significant role in the etiology and progression of liver-relatedpathologies, encompassing chronic hepatitis, fibrosis, cirrhosis, and eventual hepatocellularcarcinoma (HCC). Notably, HBV infection stands as the primary etiologicalfactor driving the development of HCC. Given the significant contribution ofHBV infection to liver diseases, a comprehensive understanding of immunedynamics in the liver microenvironment, spanning chronic HBV infection,fibrosis, cirrhosis, and HCC, is essential. In this review, we focused on thefunctional alterations of CD8+ T cells within the pathogenic livermicroenvironment from HBV infection to HCC. We thoroughly reviewed the roles ofhypoxia, acidic pH, metabolic reprogramming, amino acid deficiency, inhibitory checkpointmolecules, immunosuppressive cytokines, and the gut-liver communication in shapingthe dysfunction of CD8+ T cells in the liver microenvironment. Thesefactors significantly impact the clinical prognosis. Furthermore, we comprehensivelyreviewed CD8+ T cell-based therapy strategies for liver diseases,encompassing HBV infection, fibrosis, cirrhosis, and HCC. Strategies includeimmune checkpoint blockades, metabolic T-cell targeting therapy, therapeuticT-cell vaccination, and adoptive transfer of genetically engineered CD8+ T cells, along with the combined usage of programmed cell death protein-1/programmeddeath ligand-1 (PD-1/PD-L1) inhibitors with mitochondria-targeted antioxidants.Given that targeting CD8+ T cells at various stages of hepatitis Bvirus-induced hepatocellular carcinoma (HBV + HCC) shows promise, we reviewedthe ongoing need for research to elucidate the complex interplay between CD8+ T cells and the liver microenvironment in the progression of HBV infection toHCC. We also discussed personalized treatment regimens, combining therapeuticstrategies and harnessing gut microbiota modulation, which holds potential forenhanced clinical benefits. In conclusion, this review delves into the immunedynamics of CD8+ T cells, microenvironment changes, and therapeuticstrategies within the liver during chronic HBV infection, HCC progression, andrelated liver diseases.

Chip collection of hepatocellular carcinoma based on O2 heterogeneity from patient tissue

Hepatocellular carcinoma frequently recurs after surgery, necessitating personalized clinical approaches based on tumor avatar models. However, location-dependent oxygen concentrations resulting from the dual hepatic vascular supply drive the inherent heterogeneity of the tumor microenvironment, which presents challenges in developing an avatar model. In this study, tissue samples from 12 patients with hepatocellular carcinoma are cultured directly on a chip and separated based on preference of oxygen concentration. Establishing a dual gradient system with drug perfusion perpendicular to the oxygen gradient enables the simultaneous separation of cells and evaluation of drug responsiveness. The results are further cross-validated by implanting the chips into mice at various oxygen levels using a patient-derived xenograft model. Hepatocellular carcinoma cells exposed to hypoxia exhibit invasive and recurrent characteristics that mirror clinical outcomes. This chip provides valuable insights into treatment prognosis by identifying the dominant hepatocellular carcinoma type in each patient, potentially guiding personalized therapeutic interventions.

HIV coinfection exacerbates HBV-induced liver fibrogenesis through a HIF-1α- and TGF-β1-dependent pathway

BACKGROUND & AIMS

Persons with chronic HBV infection coinfected with HIV experience accelerated progression of liver fibrosis compared to those with HBV monoinfection. We aimed to determine whether HIV and its proteins promote HBV-induced liver fibrosis in HIV/HBV-coinfected cell culture models through HIF-1α and TGF-β1 signaling.

METHODS

The HBV-positive supernatant, purified HBV viral particles, HIV-positive supernatant, or HIV viral particles were directly incubated with cell lines or primary hepatocytes, hepatic stellate cells, and macrophages in mono or 3D spheroid coculture models. Cells were incubated with recombinant cytokines and HIV proteins including gp120. HBV sub-genomic constructs were transfected into NTCP-HepG2 cells. We also evaluated the effects of inhibitor of HIF-1α and HIV gp120 in a HBV carrier mouse model that was generated via hydrodynamic injection of the pAAV/HBV1.2 plasmid into the tail vein of wild-type C57BL/6 mice.

RESULTS

We found that HIV and HIV gp120, through engagement with CCR5 and CXCR4 coreceptors, activate AKT and ERK signaling and subsequently upregulate hypoxia-inducible factor-1α (HIF-1α) to increase HBV-induced transforming growth factor-β1 (TGF-β1) and profibrogenic gene expression in hepatocytes and hepatic stellate cells. HIV gp120 exacerbates HBV X protein-mediated HIF-1α expression and liver fibrogenesis, which can be alleviated by inhibiting HIF-1α. Conversely, TGF-β1 upregulates HIF-1α expression and HBV-induced liver fibrogenesis through the SMAD signaling pathway. HIF-1α small-interfering RNA transfection or the HIF-1α inhibitor (acriflavine) blocked HIV-, HBV-, and TGF-β1-induced fibrogenesis.

CONCLUSIONS

Our findings suggest that HIV coinfection exacerbates HBV-induced liver fibrogenesis through enhancement of the positive feedback between HIF-1α and TGF-β1 via CCR5/CXCR4. HIF-1α represents a novel target for antifibrotic therapeutic development in HBV/HIV coinfection.

IMPACT AND IMPLICATIONS

HIV coinfection accelerates the progression of liver fibrosis compared to HBV monoinfection, even among patients with successful suppression of viral load, and there is no sufficient treatment for this disease process. In this study, we found that HIV viral particles and specifically HIV gp120 promote HBV-induced hepatic fibrogenesis via enhancement of the positive feedback between HIF-1α and TGF-β1, which can be ameliorated by inhibition of HIF-1α. These findings suggest that targeting the HIF-1α pathway can reduce liver fibrogenesis in patients with HIV and HBV coinfection.

The Role of Hypoxia-Inducible Factor 1 Alpha in Acute-on-Chronic Liver Failure

Acute-on-chronic liver failure (ACLF) is associated with increased mortality. Specific therapy options are limited. Hypoxia-inducible factor 1 alpha (HIF-1α) has been linked to the pathogenesis of chronic liver disease (CLD), but the role of HIF-1α in ACLF is poorly understood. In the current study, different etiologies of CLD and precipitating events triggering ACLF were used in four rodent models. HIF-1α expression and the intracellular pathway of HIF-1α induction were investigated using real-time quantitative PCR. The results were verified by Western blotting and immunohistochemistry for extrahepatic HIF-1α expression using transcriptome analysis. Exploratory immunohistochemical staining was performed to assess HIF-1α in human liver tissue. Intrahepatic HIF-1α expression was significantly increased in all animals with ACLF, regardless of the underlying etiology of CLD or the precipitating event. The induction of HIF-1α was accompanied by the increased mRNA expression of NFkB1 and STAT3 and resulted in a marked elevation of mRNA levels of its downstream genes. Extrahepatic HIF-1α expression was not elevated. In human liver tissue samples, HIF-1α expression was elevated in CLD and ACLF. Increased intrahepatic HIF-1α expression seems to play an important role in the pathogenesis of ACLF, and future studies are pending to investigate the role of therapeutic HIF inhibitors in ACLF.

Immunotherapy, targeted therapy, and their cross talks in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a challenging malignancy with limited treatment options beyond surgery and chemotherapy. Recent advancements in targeted therapies and immunotherapy, including PD-1 and PD-L1 monoclonal antibodies, have shown promise, but their efficacy has not met expectations. Biomarker testing and personalized medicine based on genetic mutations and other biomarkers represent the future direction for HCC treatment. To address these challenges and opportunities, this comprehensive review discusses the progress made in targeted therapies and immunotherapies for HCC, focusing on dissecting the rationales, opportunities, and challenges for combining these modalities. The liver's unique physiology and the presence of fibrosis in many HCC patients pose additional challenges to drug delivery and efficacy. Ongoing efforts in biomarker development and combination therapy design, especially in the context of immunotherapies, hold promise for improving outcomes in advanced HCC. Through exploring the advancements in biomarkers and targeted therapies, this review provides insights into the challenges and opportunities in the field and proposes strategies for rational combination therapy design.

Signaling metabolite succinylacetone activates HIF-1α and promotes angiogenesis in GSTZ1-deficient hepatocellular carcinoma

Aberrant angiogenesis in hepatocellular carcinoma (HCC) is associated with tumor growth, progression, and local or distant metastasis. Hypoxia-inducible factor 1α (HIF-1α) is a transcription factor that plays a major role in regulating angiogenesis during adaptation of tumor cells to nutrient-deprived microenvironments. Genetic defects in Krebs cycle enzymes, such as succinate dehydrogenase and fumarate hydratase, result in elevation of oncometabolites succinate and fumarate, thereby increasing HIF-1α stability and activating the HIF-1α signaling pathway. However, whether other metabolites regulate HIF-1α stability remains unclear. Here, we reported that deficiency of the enzyme in phenylalanine/tyrosine catabolism, glutathione S-transferase zeta 1 (GSTZ1), led to accumulation of succinylacetone, which was structurally similar to α-ketoglutarate. Succinylacetone competed with α-ketoglutarate for prolyl hydroxylase domain 2 (PHD2) binding and inhibited PHD2 activity, preventing hydroxylation of HIF-1α, thus resulting in its stabilization and consequent expression of vascular endothelial growth factor (VEGF). Our findings suggest that GSTZ1 may serve as an important tumor suppressor owing to its ability to inhibit the HIF-1α/VEGFA axis in HCC. Moreover, we explored the therapeutic potential of HIF-1α inhibitor combined with anti-programmed cell death ligand 1 therapy to effectively prevent HCC angiogenesis and tumorigenesis in Gstz1-knockout mice, suggesting a potentially actionable strategy for HCC treatment.

Hypoxia-inducible factor affects hepatitis B virus transcripts and genome levels as well as the expression and subcellular location of the hepatitis B virus core protein

Globally, a chronic-hepatitis B virus (HBV) infection is the leading cause of hepatocellular carcinoma (HCC). The transcription factor hypoxia-inducible factor 1 (HIF1) is often elevated in HCC, including HBV-associated HCC. Previous studies have suggested that the expression of the HIF1 subunit, HIF1α, is elevated in HBV-infected hepatocytes; however, whether HIF1 activity affects the HBV lifecycle has not been fully explored. We used a liver-derived cell line and ex vivo cultured primary hepatocytes as models to determine how HIF1 affects the HBV lifecycle. We observed that HIF1 elevates HBV RNA transcript levels, core protein levels, core protein localization to the cytoplasm, and HBV genome replication. Attenuating the transcription activity of HIF1 blocked HIF1-mediated effects on the HBV lifecycle. Our studies show that HIF1 regulates various stages of the HBV lifecycle in hepatocytes and could be a therapeutic target for blocking HBV replication and the development of HBV-associated diseases.

Novel Molecular Targets for Immune Surveillance of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is a common and aggressive cancer with a high mortality rate. The incidence of HCC is increasing worldwide, and the lack of effective screening programs often results in delayed diagnosis, making it a challenging disease to manage. Immunotherapy has emerged as a promising treatment option for different kinds of cancers, with the potential to stimulate the immune system to target cancer cells. However, the current immunotherapeutic approaches for HCC have shown limited efficacy. Since HCC arises within a complex tumour microenvironment (TME) characterized by the presence of various immune and stromal cell types, the understanding of this interaction is crucial for the identification of effective therapy. In this review, we highlight recent advances in our understanding of the TME of HCC and the immune cells involved in anti-tumour responses, including the identification of new possible targets for immunotherapy. We illustrate a possible classification of HCC based on the tumour immune infiltration and give evidence about the role of SerpinB3, a serine protease inhibitor involved in the regulation of the immune response in different cancers.

Cannabis sativa demonstrates anti-hepatocellular carcinoma potentials in animal model: in silico and in vivo studies of the involvement of Akt

BACKGROUND

Targeting protein kinase B (Akt) and its downstream signaling proteins are promising options in designing novel and potent drug candidates against hepatocellular carcinoma (HCC). The present study explores the anti-HCC potentials of Cannabis sativa (C. sativa) extract via the involvement of Akt using both in silico and in vivo animal models of HCC approaches.

METHODS

Phytoconstituents of C. sativa extract obtained from Gas Chromatography Mass-spectrometry (GCSM) were docked into the catalytic domain of Akt-2. The Diethylnitrosamine (DEN) model of HCC was treated with C. sativa extract. The effects of C. sativa extract treatments on DEN model of hepatocellular carcinoma were assessed by One-way analysis of variance (ANOVA) of the treated and untreated groups RESULT: The lead phytoconstituents of C. sativa extract, Δ-9-tetrahydrocannabinol (Δ-9-THC) and cannabidiol form stable hydrophobic and hydrogen bond interactions within the catalytic domain of Akt-2. C. sativa extract (15 mg/kg and 30 mg/kg) respectively gives a 3-fold decrease in the activities of liver function enzymes when compared with the positive control (group 2). It also gives a 1.5-fold decrease in hepatic lipid peroxidation and elevates serum antioxidant enzymes' activities by 1-fold in HCC treated Wistar rats when compared with the positive control (group 2). In an animal model of hepatocellular carcinoma, C. sativa extract significantly downregulated Akt and HIF mRNAs in groups 3, 4, and 5 with 2, 1.5, 2.5-fold decrease relative to group 2. VEGF mRNA was downregulated by 1.5-fold decrease in groups 3-5 when compared to group 2. The expression of XIAP mRNA was downregulated by 1.5, 2, and 1.25-folds in groups 3, 4, and 5 respectively, in comparison with group 2. In comparison to group 2, COX-2 mRNA levels were downregulated by 1.5, 1, and 1-folds in groups 3-5. In groups 3-5, CRP mRNA was downregulated by 2-fold in comparison with group 2. In groups 3-5, p21 mRNA was upregulated by 2, 2.5, and 3-folds, respectively when compared with group 2. It upregulated p53 mRNA by 2.5, 3.5, and 2.5-folds in groups 3-5 in comparison with group 2. It downregulated AFP mRNA by 3.5, 2.5, .2.5-folds in groups 3, 4, and 5 respectively when compared with group 2. Histologic analysis showed that C. sativa extract reduced necrosis and inflammation in HCC.

CONCLUSION

C. sativa demonstrates anti-hepatocellular carcinoma potentials in an animal model of HCC and with the involvement of Akt. Its anticancer potential is mediated through antiangiogenic, proapoptotic, cycle arrest, and anti-inflammatory mechanisms. In future studies, the mechanisms of anti-HCC effects of Δ-9-tetrahydrocannabinol (Δ-9- THC) and cannabidiol via the PI3K-Akt signaling pathways should be explored.

Angiogenesis and Hepatocellular Carcinoma: From Molecular Mechanisms to Systemic Therapies

Hepatocellular carcinoma (HCC) is the most common primary liver malignancy. The hypervascular nature of the majority of HCCs and the peculiar vascular derangement occurring during liver carcinogenesis underscore the importance of angiogenesis in the development and progression of these tumors. Indeed, several angiogenic molecular pathways have been identified as deregulated in HCC. The hypervascular nature and the peculiar vascularization of HCC, as well as deregulated angiogenic pathways, represent major therapeutic targets. To a large extent, intra-arterial locoregional treatments (transarterial-(chemo)embolization) rely on tumor ischemia caused by embolization of tumor feeding arteries, even though this may represent the "primum movens" of tumor recurrence through the activation of neoangiogenesis. Considering systemic therapies, the currently available tyrosine kinase inhibitors (sorafenib, regorafenib, cabozantinib and lenvatinib) and monoclonal antibodies (ramucirumab and bevacizumab, in combination with the anti-PD-L1, atezolizumab) primarily target, among others, angiogenic pathways. Considering the importance of angiogenesis in the pathogenesis and treatment of liver cancer, in this paper, we aim to review the role of angiogenesis in HCC, addressing the molecular mechanisms, available antiangiogenic therapies and prognostic biomarkers in patients receiving these treatments.

miR-22 gene therapy treats HCC by promoting anti-tumor immunity and enhancing metabolism

MicroRNA-22 (miR-22) can be induced by beneficial metabolites that have metabolic and immune effects, including retinoic acids, bile acids, vitamin D3, and short-chain fatty acids. The tumor suppressor effects of miR-22 have been suggested, but whether miR-22 treats orthotopic hepatocellular carcinoma (HCC) is not established. The role of miR-22 in regulating tumor immunity is also poorly understood. Our data showed that miR-22 delivered by adeno-associated virus serotype 8 effectively treated HCC. Compared with FDA-approved lenvatinib, miR-22 produced better survival outcomes without noticeable toxicity. miR-22 silenced hypoxia-inducible factor 1 (HIF1α) and enhanced retinoic acid signaling in both hepatocytes and T cells. Moreover, miR-22 treatment improved metabolism and reduced inflammation. In the liver, miR-22 reduced the abundance of IL17-producing T cells and inhibited IL17 signaling by reducing the occupancy of HIF1α in the Rorc and Il17a genes. Conversely, increasing IL17 signaling ameliorated the anti-HCC effect of miR-22. Additionally, miR-22 expanded cytotoxic T cells and reduced regulatory T cells (Treg). Moreover, depleting cytotoxic T cells also abolished the anti-HCC effects of miR-22. In patients, miR-22 high HCC had upregulated metabolic pathways and reduced IL17 pro-inflammatory signaling compared with miR-22 low HCC. Together, miR-22 gene therapy can be a novel option for HCC treatment.

Impairment of aryl hydrocarbon receptor signalling promotes hepatic disorders in cancer cachexia

BACKGROUND

The aryl hydrocarbon receptor (AHR) is expressed in the intestine and liver, where it has pleiotropic functions and target genes. This study aims to explore the potential implication of AHR in cancer cachexia, an inflammatory and metabolic syndrome contributing to cancer death. Specifically, we tested the hypothesis that targeting AHR can alleviate cachectic features, particularly through the gut-liver axis.

METHODS

AHR pathways were explored in multiple tissues from four experimental mouse models of cancer cachexia (C26, BaF3, MC38 and APCMin/+ ) and from non-cachectic mice (sham-injected mice and non-cachexia-inducing [NC26] tumour-bearing mice), as well as in liver biopsies from cancer patients. Cachectic mice were treated with an AHR agonist (6-formylindolo(3,2-b)carbazole [FICZ]) or an antibody neutralizing interleukin-6 (IL-6). Key mechanisms were validated in vitro on HepG2 cells.

RESULTS

AHR activation, reflected by the expression of Cyp1a1 and Cyp1a2, two major AHR target genes, was deeply reduced in all models (C26 and BaF3, P < 0.001; MC38 and APCMin/+ , P < 0.05) independently of anorexia. This reduction occurred early in the liver (P < 0.001; before the onset of cachexia), compared to the ileum and skeletal muscle (P < 0.01; pre-cachexia stage), and was intrinsically related to cachexia (C26 vs. NC26, P < 0.001). We demonstrate a differential modulation of AHR activation in the liver (through the IL-6/hypoxia-inducing factor 1α pathway) compared to the ileum (attributed to the decreased levels of indolic AHR ligands, P < 0.001), and the muscle. In cachectic mice, FICZ treatment reduced hepatic inflammation: expression of cytokines (Ccl2, P = 0.005; Cxcl2, P = 0.018; Il1b, P = 0.088) with similar trends at the protein levels, expression of genes involved in the acute-phase response (Apcs, P = 0.040; Saa1, P = 0.002; Saa2, P = 0.039; Alb, P = 0.003), macrophage activation (Cd68, P = 0.038) and extracellular matrix remodelling (Fga, P = 0.008; Pcolce, P = 0.025; Timp1, P = 0.003). We observed a decrease in blood glucose in cachectic mice (P < 0.0001), which was also improved by FICZ treatment (P = 0.026) through hepatic transcriptional promotion of a key marker of gluconeogenesis, namely, G6pc (C26 vs. C26 + FICZ, P = 0.029). Strikingly, these benefits on glycaemic disorders occurred independently of an amelioration of the gut barrier dysfunction. In cancer patients, the hepatic expression of G6pc was correlated to Cyp1a1 (Spearman's ρ = 0.52, P = 0.089) and Cyp1a2 (Spearman's ρ = 0.67, P = 0.020).

CONCLUSIONS

With this set of studies, we demonstrate that impairment of AHR signalling contributes to hepatic inflammatory and metabolic disorders characterizing cancer cachexia, paving the way for innovative therapeutic strategies in this context.

Targeting Hypoxia-Inducible Factor-1α for the Management of Hepatocellular Carcinoma

Hypoxia-inducible factor 1 alpha (HIF-1α) is a transcription factor that regulates the cellular response to hypoxia and is upregulated in all types of solid tumor, leading to tumor angiogenesis, growth, and resistance to therapy. Hepatocellular carcinoma (HCC) is a highly vascular tumor, as well as a hypoxic tumor, due to the liver being a relatively hypoxic environment compared to other organs. Trans-arterial chemoembolization (TACE) and trans-arterial embolization (TAE) are locoregional therapies that are part of the treatment guidelines for HCC but can also exacerbate hypoxia in tumors, as seen with HIF-1α upregulation post-hepatic embolization. Hypoxia-activated prodrugs (HAPs) are a novel class of anticancer agent that are selectively activated under hypoxic conditions, potentially allowing for the targeted treatment of hypoxic HCC. Early studies targeting hypoxia show promising results; however, further research is needed to understand the effects of HAPs in combination with embolization in the treatment of HCC. This review aims to summarize current knowledge on the role of hypoxia and HIF-1α in HCC, as well as the potential of HAPs and liver-directed embolization.

Repolarization of macrophages to improve sorafenib sensitivity for combination cancer therapy

Sorafenib is the first line drug for hepatocellular carcinoma (HCC) therapy. However, HCC patients usually acquire resistance to sorafenib treatment within 6 months. Recent evidences have shown that anticancer drugs with antiangiogenesis effect (e.g., sorafenib) can aggravate the hypoxia microenvironment and promote the infiltration of more tumor-associated macrophages (TAMs) into the tumor tissues. Therefore, repolarization of TAMs phenotype could be expected to not only eliminate the influence of TAMs on sorafenib lethality to HCC cells, but also provide an additional anticancer effect to achieve combination therapy. However, immune side effects remain a great challenge due to the non-specific macrophage repolarization in normal tissues. We herein employed a tumor microenvironment (TME) pH-responsive nanoplatform to concurrently transport sorafenib and modified resiquimod (R848-C16). This nanoparticle (NP) platform is made with a TME pH-responsive methoxyl-poly(ethylene glycol)-b-poly(lactic-co-glycolic acid) copolymer. After intravenous administration, the co-delivery NPs could highly accumulate in the tumor tissues and then respond to the TME pH to detach their surface PEG chains. With this PEG detachment to enhance uptake by TAMs and HCC cells, the co-delivery NPs could combinatorially inhibit HCC tumor growth via sorafenib-mediated lethality to HCC cells and R848-mediated repolarization of TAMs into tumoricidal M1-like macrophages. STATEMENT OF SIGNIFICANCE: Anticancer drugs with antiangiogenesis effect (e.g., sorafenib) can aggravate the hypoxia microenvironment and promote the infiltration of more tumor-associated macrophages (TAMs) into the tumor tissues to restrict the anticancer effect. In this work, we designed and developed a tumor microenvironment (TME) pH-responsive nanoplatform for systemic co-delivery of sorafenib and resiquimod in hepatocellular carcinoma (HCC) therapy. These co-delivery NPs show high tumor accumulation and could respond to the TME pH to enhance uptake by TAMs and HCC cells. With the sorafenib-mediated lethality to HCC cells and R848-mediated repolarization of TAMs, the co-delivery NPs show a combinational inhibition of HCC tumor growth in both xenograft and orthotopic tumor models.

Potential Treatment Strategies for Hepatocellular Carcinoma Cell Sensitization to Sorafenib

Liver cancer is highly malignant, has a low sensitivity to chemotherapy, and is associated with poor patient prognosis. The last 3 years have seen the emergence of promising targeted therapies for the treatment of hepatocellular carcinoma (HCC). For over 10 years, before the discovery of lenvatinib, sorafenib was only first-line therapeutic agent available for the treatment of advanced HCC. However, several clinical studies have shown that a considerable proportion liver cancer patients are insensitive to sorafenib. Very few patients actually substantially benefit from treatment with sorafenib, and the overall efficacy of the drug has not been satisfactory; therefore, sorafenib has attracted considerable research attention. This study, which is based on previous studies and reports, reviews the potential mechanisms underlying sorafenib resistance and summarizes combination therapies and potential drugs that can be used to sensitize HCC cells to sorafenib.

Inflammatory processes involved in NASH-related hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the fourth leading cause of cancer-related death worldwide. In the recent years nonalcoholic fatty liver disease (NAFLD) is becoming a growing cause of HCCs and the incidence of NAFLD-related HCCs is expected to further dramatically increase by the next decade. Chronic inflammation is regarded as the driving force of NAFLD progression and a key factor in hepatic carcinogenesis. Hepatic inflammation in NAFLD results from the persistent stimulation of innate immunity in response to hepatocellular injury and gut dysbiosis as well as by the activation of adaptive immunity. However, the relative roles of innate and adaptive immunity in the processes leading to HCC are still incompletely characterized. This is due to the complex interplay between different liver cell populations, which is also strongly influenced by gut-derived bacterial products, metabolic/nutritional signals. Furthermore, carcinogenic mechanisms in NAFLD/NASH appear to involve the activation of signals mediated by hypoxia inducible factors. This review discusses recent data regarding the contribution of different inflammatory cells to NAFLD-related HCC and their possible impact on patient response to current treatments.

Hypoxia-induced circADAMTS6 in a TDP43-dependent manner accelerates glioblastoma progression via ANXA2/ NF-κB pathway

Circular RNAs (circRNAs) play important roles in the malignant progression of tumours. Herein, we identified an unreported circRNA (hsa-circ-0072688, also named circADAMTS6) that is specifically upregulated in the hypoxic microenvironment of glioblastoma and closely correlated with poor prognosis of gliblastoma patients. We found that circADAMTS6 promotes the malignant progression of glioblastoma by promoting cell proliferation and inhibiting apoptosis. Mechanistically, the hypoxic tumour microenvironment upregulates circADAMTS6 expression through transcription factor activator protein 1 (AP-1) and RNA-binding protein TAR DNA-binding protein 43 (TDP43). Moreover, circADAMTS6 accelerates glioblastoma progression by recruiting and stabilising annexin A2 (ANXA2) in a proteasomes-dependent manner. Furthermore, we found T-5224 (AP-1 inhibitor) treatment induces downregulation of circADAMTS6 and then inhibits tumour growth. In conclusion, our findings highlight the important role of the circADAMTS6/ANXA2 axis based on hypoxic microenvironment in glioblastoma progression, as well as its regulation in NF-κB pathway. Targeting circADAMTS6 is thus expected to become a novel therapeutic strategy for glioblastoma.

Overactivated NRF2 induces pseudohypoxia in hepatocellular carcinoma by stabilizing HIF-1α

Hypoxia-inducible factor-1α (HIF-1α) is highly expressed/activated in most hypoxic tumors including hepatocellular carcinoma (HCC). Another key transcription factor, nuclear factor erythroid 2-related factor 2 (NRF2), is also constitutively overactivated in HCC. In an attempt to determine whether HIF-1α and NRF2 could play complementary roles in HCC growth and progression, we investigated the crosstalk between these two transcription factors and underlying molecular mechanisms in cultured HCC cells and experimentally induced hepatocarcinogenesis as well as clinical settings. While silencing of HIF-1α in HepG2 human hepatoma cells did not alter the protein expression of NRF2, NRF2 knockdown markedly reduced the nuclear accumulation of HIF-1α without influencing its mRNA expression. In diethylnitrosamine-induced hepatocarcinogenesis in wild type mice, there was elevated NRF2 expression with concomitant upregulation of HIF-1α. However, this was abolished in Nrf2 knockout mice. NRF2 and HIF-1α co-localized and physically interacted with each other as assessed by in situ proximity ligation and immunoprecipitation assays. In addition, the interaction between NRF2 and HIF-1α as well as their overexpression was found in tumor specimens obtained from HCC patients. In normoxia, HIF-1α undergoes hydroxylation by a specific HIF-prolyl hydroxylase domain protein (PHD), which facilitates ubiquitination and proteasomal degradation of HIF-1α. NRF2 contributes to pseudohypoxia, by directly binding to the oxygen-dependent degradation (ODD) domain of HIF-1α, which hampers the PHD2-mediated hydroxylation, concomitant recruitment of von-Hippel-Lindau and ubiquitination of HIF-1α.

Hypoxia-induced factor and its role in liver fibrosis

Liver fibrosis develops as a result of severe liver damage and is considered a major clinical concern throughout the world. Many factors are crucial for liver fibrosis progression. While advancements have been made to understand this disease, no effective pharmacological drug and treatment strategies have been established that can effectively prevent liver fibrosis or even could halt the fibrotic process. Most of those advances in curing liver fibrosis have been aimed towards mitigating the causes of fibrosis, including the development of potent antivirals to inhibit the hepatitis virus. It is not practicable for many individuals; however, a liver transplant becomes the only suitable alternative. A liver transplant is an expensive procedure. Thus, there is a significant need to identify potential targets of liver fibrosis and the development of such agents that can effectively treat or reverse liver fibrosis by targeting them. Researchers have identified hypoxia-inducible factors (HIFs) in the last 16 years as important transcription factors driving several facets of liver fibrosis, making them possible therapeutic targets. The latest knowledge on HIFs and their possible role in liver fibrosis, along with the cell-specific activities of such transcription factors that how they play role in liver fibrosis progression, is discussed in this review.

The role of tumor microenvironment reprogramming in primary liver cancer chemotherapy resistance

Primary liver cancer (PLC), including hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma (ICC), and other rare tumours, is the second leading cause of cancer-related mortality. It has been a major contributor to the cancer burden worldwide. Of all primary liver cancer, HCC is the most common type. Over the past few decades, chemotherapy, immunotherapy and other therapies have been identified as applicable to the treatment of HCC. However, evidence suggests that chemotherapy resistance is associated with higher mortality rates in liver cancer. The tumour microenvironment (TME), which includes molecular, cellular, extracellular matrix(ECM), and vascular signalling pathways, is a complex ecosystem. It is now increasingly recognized that the tumour microenvironment plays a pivotal role in PLC prognosis, progression and treatment response. Cancer cells reprogram the tumour microenvironment to develop resistance to chemotherapy drugs distinct from normal differentiated tissues. Chemotherapy resistance mechanisms are reshaped during TME reprogramming. For this reason, TME reprogramming can provide a powerful tool to understand better both cancer-fate processes and regenerative, with the potential to develop a new treatment. This review discusses the recent progress of tumour drug resistance, particularly tumour microenvironment reprogramming in tumour chemotherapy resistance, and focuses on its potential application prospects.

Rhizophora mucronata Lam. (Mangrove) Bark Extract Reduces Ethanol-Induced Liver Cell Death and Oxidative Stress in Swiss Albino Mice: In Vivo and In Silico Studies

The bark extract of Rhizophora mucronata (BERM) was recently reported for its prominent in vitro protective effects against liver cell line toxicity caused by various toxicants, including ethanol. Here, we aimed to verify the in vivo hepatoprotective effects of BERM against ethanol intoxication with the prediction of potential targets employing in silico studies. An oral administration of different concentrations (100, 200 and 400 mg/kg body weight) of BERM before high-dose ethanol via intraperitoneal injection was performed in mice. On day 7, liver sections were dissected for histopathological examination. The ethanol intoxication caused liver injury and large areas of necrosis. The pre-BERM administration decreased the ethanol-induced liver damage marker tumor necrosis factor-alpha (TNF-α) expression, reduced hepatotoxicity revealed by nuclear deoxyribonucleic acid (DNA) fragmentation and decreased oxidative stress indicated by malondialdehyde and glutathione contents. Our in silico studies have identified BERM-derived metabolites exhibiting the highest predicted antioxidant and free radical scavenger activities. Molecular docking studies showed that most of the metabolites were predicted to be enzyme inhibitors such as carbonic anhydrase inhibitors, which were reported to stimulate the antioxidant defense system. The metabolites predominantly presented acceptable pharmacokinetics and safety profiles, suggesting them as promising new antioxidant agents. Altogether, the BERM extract exerts antioxidative activities and shows promising hepatoprotective effects against ethanol intoxication. Identification of related bioactive compounds will be of interest for future use at physiological concentrations in ethanol-intoxicated individuals.

Chronic intermittent hypoxia promotes early intrahepatic endothelial impairment in rats with nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is a progressive disease that ranges from simple steatosis to cirrhosis. Obstructive sleep apnea syndrome (OSAS) and chronic intermittent hypoxia (CIH) are implicated in the pathogenesis of NAFLD. However, the overlapping consequences of CIH on liver sinusoidal endothelial function over time in NAFLD are largely unknown. We explored endothelial dysfunction in a rat model of NAFLD with a high-fat diet exposed to CIH [12 h/day, every 30 s to fractional concentration of oxygen ([Formula: see text] 8%-10%]. The livers were isolated and perfused, and the endothelial function was determined by testing the vasodilation of the liver circulation to increased concentrations of acetylcholine and von Willebrand factor (vWF) and intercellular adhesion molecule 1 (ICAM-1) expression. Phosphorylated endothelial nitric oxide synthase (p-eNOS), cGMP, and oxidative stress were assessed to determine nitric oxide bioavailability. Inflammation and fibrosis were evaluated by transaminases, myeloperoxidase activity, hydroxyproline, and histological evaluation. Hypoxia-inducible factors (HIFs) were studied as a marker of hypoxia and after a second insult with acetaminophen. CIH exposure provoked typical systemic features of OSAS and provoked a decreased response in vasodilation to acetylcholine. This was associated with increased oxidative stress and reduced p-eNOS and cGMP. The microcirculation impairment due to CIH preceded significant hepatic inflammation and fibrotic changes, despite the presence of HIF expression. In conclusion, CIH exacerbates endothelial dysfunction in NAFLD rats associated with increased oxidative stress and reduced nitric oxide bioavailability. This occurs before inflammation and fibrosis establish. Our results suggest that with CIH endothelial dysfunction should be considered an early target.NEW & NOTEWORTHY We believe the findings are of relevance because we demonstrate that chronic intermittent hypoxia further augments impaired hepatic endothelial dysfunction in nonalcoholic fatty liver disease rats. Because obstructive sleep apnea syndrome is associated with systemic endothelial dysfunction in cardiovascular disorders, and chronic intermittent hypoxia is an independent and reversible risk factor for hypertension and coronary artery disease, we hypothesized that this entity may be of potential relevance in the pathophysiology of nonalcoholic fatty liver disease.

HIF-2α regulates proliferation, invasion, and metastasis of hepatocellular carcinoma cells via VEGF/Notch1 signaling axis after insufficient radiofrequency ablation

Background and Aims

Although insufficient radiofrequency ablation (RFA) promotes the recurrence and metastasis of liver cancer, the underlying mechanism remains unclear. This study aimed to investigate the role and mechanism of HIF-2α in hepatocellular carcinoma cells (HCCs) after Insufficient RFA.

Methods

We established a model of insufficient RFA in MHCC97H hepatoma cells and screened for stable sublines. We inhibited HIF-2α expression in the Insufficient RFA group using PT2385 and assessed the resulting changes in proliferation and biological function of HCCs. Cell viability and proliferation were detected by the MTT method, and scratch and Transwell chamber invasion tests detected migration and invasion abilities of HCCs. The mRNA and protein expression levels of VEGF, HIF-2α, and Notch1 were detected using qPCR, immunofluorescence, and western blotting.

Results

Compared with normal HCCs without RFA treatment, insufficient RFA enhanced the proliferation and invasion abilities of hepatocellular carcinoma subline MHCC97H (P < 0.001), as well as their migration ability (P = 0.046). The HIF-2α-specific inhibitor PT2385 downregulated the migration (P = 0.009) and invasion (P < 0.001) of MHCC97H cells but did not affect cell proliferation (P > 0.05). Insufficient ablation increased the mRNA and protein expression of VEGF, HIF-2α, and Notch1 in HCCs, whereas inhibition of HIF-2α reversed these changes.

Conclusions

Insufficient RFA increases the proliferation, migration, and invasion of HCCs via the HIF-2α/VEGF/Notch1 signaling axis; HIF-2α is a potential target for novel treatments of HCC after insufficient RFA.

Comparative transcriptome analysis reveals physiological responses in liver tissues of Epinephelus coioides under acute hypoxia stress

Hypoxia is a common stressor for aquatic animals, including Epinephelus coioides, with a considerable impact on sustainable aquaculture. E. coioides is a widely consumed fish in China owing to its high nutritious value and taste. However, water hypoxia caused by high density culture process has become a great threat to E. coioides culture, and its response to hypoxia stress has not been discussed before. Therefore, the aim of this study was to examine the response of E. coioides to acute hypoxia using transcriptomic techniques. To this end, RNA sequencing was performed on the liver tissues of fish exposed to normoxic and hypoxic conditions for 1 h. The results presented 503 differentially expressed genes (DEGs) in the liver tissue of fish exposed to hypoxic condition compared with those in the normoxic group. Enrichment analysis using the Gene Ontology database showed that the DEGs were mainly enriched for functions related to cell apoptosis signaling pathways, insulin resistance, antioxidant enzymes, and glycolysis/gluconeogenesis signaling pathways. KEGG enrichment analysis showed that HIF-1, PI3K-AKT, IL-17, NF-kappa B, and MAPK signaling pathways were significantly enriched by the DEGs. The DEGs were mainly involved in immune response, inflammatory response, cell apoptosis regulation, energy metabolism, and substance metabolism. Additionally, the hypoxia response in E. coioides was mainly regulated via the PI3K-AKT-HIF-1 signaling axis. Overall, the findings of this study contribute to the understanding of hypoxia stress response in E. coioides, and provides target genes for breeding hypoxia-tolerant Epinephelus spp.

Dissecting a hypoxia-related angiogenic gene signature for predicting prognosis and immune status in hepatocellular carcinoma

Background

Hypoxia and angiogenesis, as prominent characteristics of malignant tumors, are implicated in the progression of hepatocellular carcinoma (HCC). However, the role of hypoxia in the angiogenesis of liver cancer is unclear. Therefore, we explored the regulatory mechanisms of hypoxia-related angiogenic genes (HRAGs) and the relationship between these genes and the prognosis of HCC.

Methods

The transcriptomic and clinical data of HCC samples were downloaded from public datasets, followed by identification of hypoxia- and angiogenesis-related genes in the database. A gene signature model was constructed based on univariate and multivariate Cox regression analyses, and validated in independent cohorts. Kaplan-Meier survival and time-dependent receiver operating characteristic (ROC) curves were generated to evaluate the model’s predictive capability. Gene set enrichment analysis (GSEA) was performed to explore signaling pathways regulated by the gene signature. Furthermore, the relationships among gene signature, immune status, and response to anti-angiogenesis agents and immune checkpoint blockade (ICB) were analyzed.

Results

The prognostic model was based on three HRAGs (ANGPT2, SERPINE1 and SPP1). The model accurately predicted that low-risk patients would have longer overall survival than high-risk patients, consistent with findings in other cohorts. GSEA indicated that high-risk group membership was significantly associated with hypoxia, angiogenesis, the epithelial-mesenchymal transition, and activity in immune-related pathways. The high-risk group also had more immunosuppressive cells and higher expression of immune checkpoints such as PD-1 and PD-L1. Conversely, the low-risk group had a better response to anti-angiogenesis and ICB therapy.

Conclusions

The gene signature based on HRAGs was predictive of prognosis and provided an immunological perspective that will facilitate the development of personalized therapies.

Hypoxic Hepatocellular Carcinoma Cells Acquire Arsenic Trioxide Resistance by Upregulating HIF-1α Expression

BACKGROUND

Although arsenic trioxide (ATO) is used in the treatment of advanced hepatocellular carcinoma (HCC) in clinical trials, it is not satisfactory in terms of improving HCC patients' overall survival. Intratumoral hypoxia and overexpression of hypoxia-inducible factor-1α (HIF-1α) may result in ATO resistance and tumor progression.

AIMS

We investigated the mechanisms involving HIF-1α expression and acquired ATO chemoresistance in HCC cells and mice.

METHODS

The therapeutic effects of ATO in normoxic and hypoxic HCC cells were assessed using cell viability and apoptosis assays in vitro and a xenograft model in vivo. mRNA and protein expression of HIF-1α, P-glycoprotein, and VEGF were measured by qRT-PCR and western blotting. HIF-1α inhibition was performed to investigate the mechanism of ATO resistance. VEGF secretion was tested using ELISA and tube formation assays.

RESULTS

Compared to normoxic cells, hypoxic HCC cells were more resistant to ATO, with higher IC₅₀ values and less apoptosis, and upregulated HIF-1α protein expression, accompanied with the enhancement of P-glycoprotein and VEGF synthesis after ATO treatment. VEGF secretion was elevated in the supernatant of ATO-treated HCC cells, and this change can potentiate angiogenesis in vitro. HIF-1α inhibition attenuated ATO resistance and angiogenesis and promoted the anticancer effects of ATO both in vitro and in vivo by downregulating therapy-induced P-glycoprotein and VEGF overexpression.

CONCLUSIONS

Hypoxic HCC cells acquire ATO resistance by upregulating HIF-1α levels; thus, combining ATO with a HIF-1α-targeting agent may lead to enhanced antitumor effects in HCC.

Ephrin-A3/EphA2 axis regulates cellular metabolic plasticity to enhance cancer stemness in hypoxic hepatocellular carcinoma

BACKGROUND & AIMS

The highly proliferative nature of hepatocellular carcinoma (HCC) frequently results in a hypoxic intratumoural microenvironment, which creates a therapeutic challenge owing to a lack of mechanistic understanding of the phenomenon. We aimed to identify critical drivers of HCC development and progression in the hypoxic microenvironment.

METHODS

We performed integrative analysis of multiple transcriptomic and genomic profiles specific for HCC and hypoxia and identified the Ephrin-A3/Eph receptor A2 (EphA2) axis as a clinically relevant and hypoxia-inducible signalling axis in HCC. The functional significance and mechanistic consequences of the Ephrin-A3/EphA2 axis were examined in EFNA3- and EPHA2- knockdown/overexpressing HCC cells. The potential downstream pathways were investigated by transcriptome sequencing, quantitative reverse-transcription PCR, western blotting analysis and metabolomics.

RESULTS

EFNA3 was frequently upregulated in HCC and its overexpression was associated with more aggressive tumour behaviours. HIF-1α directly and positively regulated EFNA3 expression under hypoxia. EFNA3 functionally contributed to self-renewal, proliferation and migration in HCC cells. EphA2 was identified as a key functional downstream mediator of EFNA3. Functional characterisation of the Ephrin-A3/EphA2 forward-signalling axis demonstrated a promotion of self-renewal ability and tumour initiation. Mechanistically, the Ephrin-A3/EphA2 axis promoted the maturation of SREBP1 and expression of its transcriptional target, ACLY, was significantly associated with the expression of EFNA3 and hypoxia markers in clinical cohorts. The metabolic signature of EPHA2 and ACLY stable knockdown HCC cells demonstrated significant overlap in fatty acid, cholesterol and tricarboxylic acid cycle metabolite profiles. ACLY was confirmed to mediate the self-renewal function of the Ephrin-A3/EphA2 axis.

CONCLUSIONS

Our findings revealed the novel role of the Ephrin-A3/EphA2 axis as a hypoxia-sensitive modulator of HCC cell metabolism and a key contributor to HCC initiation and progression.

LAY SUMMARY

Hepatocellular carcinoma (HCC) is a fast-growing tumour; hence, areas of the tumour often have insufficient vasculature and become hypoxic. The presence of hypoxia within tumours has been shown to negatively impact on the survival of patients with tumours, including HCC. Herein, we identified the Ephrin-A3/EphA2 axis as a key functional driver of tumour initiation and progression in response to hypoxia. Additionally, we showed that SREBP1-ACLY-mediated metabolic rewiring was an important downstream effector that induced cancer stemness in response to Ephrin-A3/EphA2 forward-signalling.

Regulatory T cells and their associated factors in hepatocellular carcinoma development and therapy

Liver cancer is the third leading cause of cancer-related death worldwide with primary type hepatocellular carcinoma (HCC). Factors, including carcinogens, infection of hepatitis viruses, alcohol abuse, and non-alcoholic fatty liver disease (NAFLD), can induce HCC initiation and promote HCC progression. The prevalence of NAFLD accompanying the increased incidence of obesity and type 2 diabetes becomes the most increasing factor causing HCC worldwide. However, the benefit of current therapeutic options is still limited. Intrahepatic immunity plays critically important roles in HCC initiation, development, and progression. Regulatory T cells (Tregs) and their associated factors such as metabolites and secreting cytokines mediate the immune tolerance of the tumor microenvironment in HCC. Therefore, targeting Tregs and blocking their mediated factors may prevent HCC progression. This review summarizes the functions of Tregs in HCC-inducing factors including alcoholic and NAFLD, liver fibrosis, cirrhosis, and viral infections. Overall, a better understanding of the role of Tregs in the development and progression of HCC provides treatment strategies for liver cancer treatment.

Prospective Analysis of Proteins Carried in Extracellular Vesicles with Clinical Outcome in Hepatocellular Carcinoma

Background: Extracellular vehicles (EVs) contain different proteins that relay information between tumor cells, thus promoting tumorigenesis. Therefore, EVs can serve as an ideal marker for tumor pathogenesis and clinical application. Objective: Here, we characterised EV-specific proteins in hepatocellular carcinoma (HCC) samples and established their potential protein-protein interaction (PPI) networks. Materials and Methods: We used multi-dimensional bioinformatics methods to mine a network module to use as a prognostic signature and validated the model's prediction using additional datasets. The relationship between the prognostic model and tumor immune cells or the tumor microenvironment status was also examined. Results: 1134 proteins from 316 HCC samples were mapped to the exoRBase database. HCC-specific EVs specifically expressed a total of 437 proteins. The PPI network revealed 321 proteins and 938 interaction pathways, which were mined to identify a three network module (3NM) with significant prognostic prediction ability. Validation of the 3NM in two more datasets demonstrated that the model outperformed the other signatures in prognostic prediction ability. Functional analysis revealed that the network proteins were involved in various tumor-related pathways. Additionally, these findings demonstrated a favorable association between the 3NM signature and macrophages, dendritic, and mast cells. Besides, the 3NM revealed the tumor microenvironment status, including hypoxia and inflammation. Conclusion: These findings demonstrate that the 3NM signature reliably predicts HCC pathogenesis. Therefore, the model may be used as an effective prognostic biomarker in managing patients with HCC.

AKR1C1 promotes non-small cell lung cancer proliferation via crosstalk between HIF-1α and metabolic reprogramming

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AKR1C1 accelerates the proliferation of NSCLC cells.

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AKR1C1 remodels metabolism in NSCLC cells.

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HIF-1α may play a vital role in AKR1C1-mediated metabolic reprogramming.

Non-small cell lung cancer (NSCLC) ranks first among cancer death worldwide. Despite efficacy and safety priority, targeted therapy only benefits ∼30% patients, leading to the unchanged survival rates for whole NSCLC patients. Metabolic reprogramming occurs to offer energy and intermediates for fuelling cancer cells proliferation. Thus, mechanistic insights into metabolic reprogramming may shed light upon NSCLC proliferation and find new proper targets for NSCLC treatment. Herein, we used loss- and gain-of-function experiments to uncover that highly expressed aldo-keto reductase family1 member C1 (AKR1C1) accelerated NSCLC cells proliferation via metabolic reprogramming. Further molecular profiling analyses demonstrated that AKR1C1 augmented the expression of hypoxia-inducible factor 1-alpha (HIF-1α), which could drive tumour metabolic reprogramming. What's more, AKR1C1 significantly correlated with HIF-1α signaling, which predicted poor prognosis for NSCLC patients. Collectively, our data display that AKR1C1 reprograms tumour metabolism to promote NSCLC cells proliferation by activating HIF-1α. These newly acquired data not only establish the specific role for AKR1C1 in metabolic reprogramming, but also hint to the possibility that AKR1C1 may be a new therapeutic target for NSCLC treatment.

Modelling liver cancer microenvironment using a novel 3D culture system

The tumor microenvironment and its contribution to tumorigenesis has been a focal highlight in recent years. A two-way communication between the tumor and the surrounding microenvironment sustains and contributes to the growth and metastasis of tumors. Progression and metastasis of hepatocellular carcinoma (HCC) have been reported to be exceedingly influenced by diverse microenvironmental cues. In this study, we present a 3D-culture model of liver cancer to better mimic in vivo tumor settings. By creating novel 3D co-culture model that combines free-floating and scaffold-based 3D-culture techniques of liver cancer cells and fibroblasts, we aimed to establish a simple albeit reproducible ex vivo cancer microenvironment model that captures tumor-stroma interactions. The model presented herein exhibited unique gene expression and protein expression profiles when compared to 2D and 3D mono-cultures of liver cancer cells. Our results showed that in vivo like conditions cannot be mimicked by simply growing cancer cells as spheroids, but by co-culturing them with 3D fibroblast with which they were able to crosstalk. This was evident by the upregulation of several pathways involved in HCC, and the increase in secreted factors by co-cultured cancer cells, many of which are also involved in tumor-stroma interactions. Compared to the conventional 2D culture, the proposed model exhibits an increase in the expression of genes associated with development, progression, and poor prognosis of HCC. Our results correlated with an aggressive outcome that better mirrors in vivo HCC, and therefore, a more reliable platform for molecular understanding of HCC.

Copper Isotope Evidence of Oxidative Stress-Induced Hepatic Breakdown and the Transition to Hepatocellular Carcinoma

Background and Aims

Hepatocellular carcinoma (HCC) is the third leading cause of cancer-related death worldwide, and finding a single reliable biomarker to follow liver degradation is a challenging task. To document the relationship between liver failure, hypoxia, and HCC, copper isotope variations (δ65Cu) were evaluated in the serum of HCC-negative and HCC-positive patients as a biomarker of hepatic failure.

Methods

We analyzed Cu isotope variations in serum samples from 293 patients with potentially degraded liver functions presenting hepatitis B virus, hepatitis C virus, nonalcoholic steatohepatitis, and alcohol uptake (OH) etiologies and 105 controls. Ninety-five of the patients were diagnosed with HCC.

Results

On average, the δ65Cu values of the serum of patients with F3-F4 fibrosis score or HCC-positive are low. The Cu isotope data are strikingly bimodal with well-defined δ65Cu modes which imperfectly reflect etiology. The population with normal values (ca -0.3‰) is progressively replaced by a population with atypical δ65Cu values (ca -0.8‰), which reflects the progressive degradation of hepatic functions.

Conclusion

The clear bimodality does not correspond to a progressive shift of the δ65Cu values but to a replacement of one population by another. This bimodality sheds light on the persisting difficulties epitomized by α-fetoprotein in finding high-sensitivity and high-specificity HCC biomarkers. It is interpreted as a switch in the resistance of hepatic tissues to the oxidative stress that eventually leads to HCC oncogenesis.

Advance of SOX Transcription Factors in Hepatocellular Carcinoma: From Role, Tumor Immune Relevance to Targeted Therapy

Simple Summary

Hepatocellular carcinoma (HCC) is one of the deadliest human health burdens worldwide. However, the molecular mechanism of HCC development is still not fully understood. Sex determining region Y-related high-mobility group box (SOX) transcription factors not only play pivotal roles in cell fate decisions during development but also participate in the initiation and progression of cancer. Given the significance of SOX factors in cancer and their ‘undruggable’ properties, we summarize the role and molecular mechanism of SOX family members in HCC and the regulatory effect of SOX factors in the tumor immune microenvironment (TIME) of various cancers. For the first time, we analyze the association between the levels of SOX factors and that of immune components in HCC, providing clues to the pivotal role of SOX factors in the TIME of HCC. We also discuss the opportunities and challenges of targeting SOX factors for cancer.

Abstract

Sex determining region Y (SRY)-related high-mobility group (HMG) box (SOX) factors belong to an evolutionarily conserved family of transcription factors that play essential roles in cell fate decisions involving numerous developmental processes. In recent years, the significance of SOX factors in the initiation and progression of cancers has been gradually revealed, and they act as potential therapeutic targets for cancer. However, the research involving SOX factors is still preliminary, given that their effects in some leading-edge fields such as tumor immune microenvironment (TIME) remain obscure. More importantly, as a class of ‘undruggable’ molecules, targeting SOX factors still face considerable challenges in achieving clinical translation. Here, we mainly focus on the roles and regulatory mechanisms of SOX family members in hepatocellular carcinoma (HCC), one of the fatal human health burdens worldwide. We then detail the role of SOX members in remodeling TIME and analyze the association between SOX members and immune components in HCC for the first time. In addition, we emphasize several alternative strategies involved in the translational advances of SOX members in cancer. Finally, we discuss the alternative strategies of targeting SOX family for cancer and propose the opportunities and challenges they face based on the current accumulated studies and our understanding.

Oxidative Stress in Non-Alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease (NAFLD) is a challenging disease caused by multiple factors, which may partly explain why it still remains an orphan of adequate therapies. This review highlights the interaction between oxidative stress (OS) and disturbed lipid metabolism. Several reactive oxygen species generators, including those produced in the gastrointestinal tract, contribute to the lipotoxic hepatic (and extrahepatic) damage by fatty acids and a great variety of their biologically active metabolites in a “multiple parallel-hit model”. This leads to inflammation and fibrogenesis and contributes to NAFLD progression. The alterations of the oxidant/antioxidant balance affect also metabolism-related organelles, leading to lipid peroxidation, mitochondrial dysfunction, and endoplasmic reticulum stress. This OS-induced damage is at least partially counteracted by the physiological antioxidant response. Therefore, modulation of this defense system emerges as an interesting target to prevent NAFLD development and progression. For instance, probiotics, prebiotics, diet, and fecal microbiota transplantation represent new therapeutic approaches targeting the gut microbiota dysbiosis. The OS and its counter-regulation are under the influence of individual genetic and epigenetic factors as well. In the near future, precision medicine taking into consideration genetic or environmental epigenetic risk factors, coupled with new OS biomarkers, will likely assist in noninvasive diagnosis and monitoring of NAFLD progression and in further personalizing treatments.

Function of BCLAF1 in human disease

Originally identified as a regulator of apoptosis and transcription, B-cell lymphoma-2-associated transcription factor 1 (BCLAF1) has since been shown to be associated with a multitude of biological processes, such as DNA damage response, splicing and processing of pre-mRNA, T-cell activation, lung development, muscle cell proliferation and differentiation, autophagy, ischemia-reperfusion injury, and viral infection. In recent years, an increasing amount of evidence has shown that BCLAF1 acts as either a tumor promoter or tumor suppressor in tumorigenesis depending on the cellular context and the type of cancer. Even in the same tumor type, BCLAF1 may have opposite effects. In the present review, the subcellular localization, structural features, mutations within BCLAF1 will be described, then the regulation of BCLAF1 and its downstream targets will be analyzed. Furthermore, the different roles and possible mechanisms of BCLAF1 in tumorigenesis will also be highlighted and discussed. Finally, BCLAF1 may be considered as a potential target for cancer therapy in the future.

Quercetin Liposomal Nanoformulation for Ischemia and Reperfusion Injury Treatment

Ischemia and reperfusion injury (IRI) is a common complication caused by inflammation and oxidative stress resulting from liver surgery. Current therapeutic strategies do not present the desirable efficacy, and severe side effects can occur. To overcome these drawbacks, new therapeutic alternatives are necessary. Drug delivery nanosystems have been explored due to their capacity to improve the therapeutic index of conventional drugs. Within nanocarriers, liposomes are one of the most successful, with several formulations currently in the market. As improved therapeutic outcomes have been demonstrated by using liposomes as drug carriers, this nanosystem was used to deliver quercetin, a flavonoid with anti-inflammatory and antioxidant properties, in hepatic IRI treatment. In the present work, a stable quercetin liposomal formulation was developed and characterized. Additionally, an in vitro model of ischemia and reperfusion was developed with a hypoxia chamber, where the anti-inflammatory potential of liposomal quercetin was evaluated, revealing the downregulation of pro-inflammatory markers. The anti-inflammatory effect of quercetin liposomes was also assessed in vivo in a rat model of hepatic IRI, in which a decrease in inflammation markers and enhanced recovery were observed. These results demonstrate that quercetin liposomes may provide a significant tool for addressing the current bottlenecks in hepatic IRI treatment.

Dual Lactate Clearance in the Viability Assessment of Livers Donated After Circulatory Death With Ex Situ Normothermic Machine Perfusion

Supplemental Digital Content is available in the text.

Perfusate lactate clearance (LC) is considered one of the useful indicators of liver viability assessment during normothermic machine perfusion (NMP); however, the applicable scope and potential mechanisms of LC remain poorly defined in the setting of liver donation after circulatory death.

Folliculin impairs breast tumor growth by repressing TFE3-dependent induction of the Warburg effect and angiogenesis

Growing tumors exist in metabolically compromised environments that require activation of multiple pathways to scavenge nutrients to support accelerated rates of growth. The folliculin (FLCN) tumor suppressor complex (FLCN, FNIP1, FNIP2) is implicated in the regulation of energy homeostasis via 2 metabolic master kinases: AMPK and mTORC1. Loss-of-function mutations of the FLCN tumor suppressor complex have only been reported in renal tumors in patients with the rare Birt-Hogg-Dube syndrome. Here, we revealed that FLCN, FNIP1, and FNIP2 are downregulated in many human cancers, including poor-prognosis invasive basal-like breast carcinomas where AMPK and TFE3 targets are activated compared with the luminal, less aggressive subtypes. FLCN loss in luminal breast cancer promoted tumor growth through TFE3 activation and subsequent induction of several pathways, including autophagy, lysosomal biogenesis, aerobic glycolysis, and angiogenesis. Strikingly, induction of aerobic glycolysis and angiogenesis in FLCN-deficient cells was dictated by the activation of the PGC-1α/HIF-1α pathway, which we showed to be TFE3 dependent, directly linking TFE3 to Warburg metabolic reprogramming and angiogenesis. Conversely, FLCN overexpression in invasive basal-like breast cancer models attenuated TFE3 nuclear localization, TFE3-dependent transcriptional activity, and tumor growth. These findings support a general role of a deregulated FLCN/TFE3 tumor suppressor pathway in human cancers.

Bruceine D inhibits HIF-1α-mediated glucose metabolism in hepatocellular carcinoma by blocking ICAT/β-catenin interaction

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer-related deaths, characterized by highly hypoxic tumor microenvironment. Hypoxia-inducible factor-1α (HIF-1α) is a major regulator involved in cellular response to changes of oxygen levels, supporting the adaptation of tumor cells to hypoxia. Bruceine D (BD) is an isolated natural quassinoid with multiple anti-cancer effects. Here, we identified BD could significantly inhibit the HIF-1α expression and its subsequently mediated HCC cell metabolism. Using biophysical proteomics approaches, we identified inhibitor of β-catenin and T-cell factor (ICAT) as the functional target of BD. By targeting ICAT, BD disrupted the interaction of β-catenin and ICAT, and promoted β-catenin degradation, which in turn induced the decrease of HIF-1α expression. Furthermore, BD could inhibit HCC cells proliferation and tumor growth in vivo, and knockdown of ICAT substantially increased resistance to BD treatment in vitro. Our data highlight the potential of BD as a modulator of β-catenin/HIF-1α axis mediated HCC metabolism.

Hepatocyte-Specific Deletion of HIF2α Prevents NASH-Related Liver Carcinogenesis by Decreasing Cancer Cell Proliferation

BACKGROUND & AIMS

Hypoxia and hypoxia-inducible factors (HIFs) are involved in chronic liver disease progression. We previously showed that hepatocyte HIF-2α activation contributed significantly to nonalcoholic fatty liver disease progression in experimental animals and human patients. In this study, using an appropriate genetic murine model, we mechanistically investigated the involvement of hepatocyte HIF-2α in experimental nonalcoholic steatohepatitis (NASH)-related carcinogenesis.

METHODS

The role of HIF-2α was investigated by morphologic, cellular, and molecular biology approaches in the following: (1) mice carrying hepatocyte-specific deletion of HIF-2α (HIF-2α^-/- mice) undergoing a NASH-related protocol of hepatocarcinogenesis; (2) HepG2 cells stably transfected to overexpress HIF-2α; and (3) liver specimens from NASH patients with hepatocellular carcinoma.

RESULTS

Mice carrying hepatocyte-specific deletion of HIF-2α (hHIF-2α^-/-) showed a significant decrease in the volume and number of liver tumors compared with wild-type littermates. These effects did not involve HIF-1α changes and were associated with a decrease of cell proliferation markers proliferating cell nuclear antigen and Ki67. In both human and rodent nonalcoholic fatty liver disease-related tumors, HIF-2α levels were strictly associated with hepatocyte production of SerpinB3, a mediator previously shown to stimulate liver cancer cell proliferation through the Hippo/Yes-associated protein (YAP)/c-Myc pathway. Consistently, we observed positive correlations between the transcripts of HIF-2α, YAP, and c-Myc in individual hepatocellular carcinoma tumor masses, while HIF-2α deletion down-modulated c-Myc and YAP expression without affecting extracellular signal-regulated kinase 1/2, c-Jun N-terminal kinase, and AKT-dependent signaling. In vitro data confirmed that HIF-2α overexpression induced HepG2 cell proliferation through YAP-mediated mechanisms.

CONCLUSIONS

These results indicate that the activation of HIF-2α in hepatocytes has a critical role in liver carcinogenesis during NASH progression, suggesting that HIF-2α-blocking agents may serve as novel putative therapeutic tools.

Lack of MOF Decreases Susceptibility to Hypoxia and Promotes Multidrug Resistance in Hepatocellular Carcinoma via HIF-1α

Hypoxia-inducible factor-1α (HIF-1α) promotes oncogenesis in hepatocellular carcinoma and is functionally linked to cell proliferation, chemoresistance, metastasis and angiogenesis. It has been confirmed that the low expression level of Males absent on the first (MOF) in hepatocellular carcinoma leads to poor prognosis of patients. However, potential regulatory mechanisms of MOF in response to hypoxia remain elusive. Our results demonstrate that MOF expression is negatively associated with HIF-1α expression in hepatocellular carcinoma tissues and in response to chloride-mimicked hypoxia in hepatocellular carcinoma cell lines. MOF regulates HIF-1α mRNA expression and also directly binds to HIF-1α to mediate HIF-1α N-terminal lysine acetylation, ubiquitination and degradation, with downstream effects on MDR1 levels. Functional inactivation of MOF enhances HIF-1α stability and causes cell tolerance to hypoxia that is insensitive to histone deacetylase inhibitor treatment. Dysfunction of MOF in hepatocellular carcinoma cells also results in chemoresistance to trichostatin A, sorafenib and 5-fluorouracil via HIF-1α. Our results suggest that MOF regulates hypoxia tolerance and drug resistance in hepatocellular carcinoma cells by modulating both HIF-1α mRNA expression and N-terminal acetylation of HIF-1α, providing molecular insight into MOF-dependent oncogenic function of hepatocellular carcinoma cells.

A human liver cell-based system modeling a clinical prognostic liver signature for therapeutic discovery

Chronic liver disease and hepatocellular carcinoma (HCC) are life-threatening diseases with limited treatment options. The lack of clinically relevant/tractable experimental models hampers therapeutic discovery. Here, we develop a simple and robust human liver cell-based system modeling a clinical prognostic liver signature (PLS) predicting long-term liver disease progression toward HCC. Using the PLS as a readout, followed by validation in nonalcoholic steatohepatitis/fibrosis/HCC animal models and patient-derived liver spheroids, we identify nizatidine, a histamine receptor H2 (HRH2) blocker, for treatment of advanced liver disease and HCC chemoprevention. Moreover, perturbation studies combined with single cell RNA-Seq analyses of patient liver tissues uncover hepatocytes and HRH2+, CLEC5Ahigh, MARCOlow liver macrophages as potential nizatidine targets. The PLS model combined with single cell RNA-Seq of patient tissues enables discovery of urgently needed targets and therapeutics for treatment of advanced liver disease and cancer prevention.

The immunological and metabolic landscape in primary and metastatic liver cancer

The liver is the sixth most common site of primary cancer in humans, and generally arises in a background of cirrhosis and inflammation. Moreover, the liver is frequently colonized by metastases from cancers of other organs (particularly the colon) because of its anatomical location and organization, as well as its unique metabolic and immunosuppressive environment. In this Review, we discuss how the hepatic microenvironment adapts to pathologies characterized by chronic inflammation and metabolic alterations. We illustrate how these immunological or metabolic changes alter immunosurveillance and thus hinder or promote the development of primary liver cancer. In addition, we describe how inflammatory and metabolic niches affect the spreading of cancer metastases into or within the liver. Finally, we review the current therapeutic options in this context and the resulting challenges that must be surmounted.

Activation of FcRn Mediates a Primary Resistance Response to Sorafenib in Hepatocellular Carcinoma by Single-Cell RNA Sequencing

Sorafenib is the first-line therapeutic option for advanced hepatocellular carcinoma (HCC). Many patients exhibit a primary resistance (PR) response after initial treatment. In previous studies, compared to acquired resistance, the mechanism of PR is unclear. The present study aimed to evaluate the response of patient samples to sorafenib by patient-derived xenograft (PDX) models, and the differences at the transcriptome level between the sorafenib PR group and the sorafenib sensitive group were analyzed by single-cell sequencing technology. A specific cell cluster may be differentiated by the liver bud hepatic cells, and the JUN transcription factors in this cell cluster were highly activated. The albumin is secreted by other cell clusters, and the cluster stimulates the FcRn complex receptor to activate the HIF pathway and cell proliferation, resulting in a poor response to sorafenib. These findings are validated by both cell communication analysis and experiments. Thus, the current studies provided a novel approach for the treatment of sorafenib-resistant HCC.