FGF19 Protects Hepatocellular Carcinoma Cells against Endoplasmic Reticulum Stress via Activation of FGFR4-GSK3β-Nrf2 Signaling

Bromocriptine sensitivity in bromocriptine-induced drug-resistant prolactinomas is restored by inhibiting FGF19/FGFR4/PRL

PURPOSE

At present, various treatment strategies are available for pituitary adenomas, including medications, surgery and radiation. The guidelines indicate that pharmacological treatments, such as bromocriptine (BRC) and cabergoline (CAB), are important treatments for prolactinomas, but drug resistance is an urgent problem that needs to be addressed. Therefore, exploring the mechanism of drug resistance in prolactinomas is beneficial for clinical treatment.

METHODS

In our research, BRC-induced drug-resistant cells were established. Previous RNA sequencing data and an online database were used for preliminary screening of resistance-related genes. Cell survival was determined by Cell Counting Kit-8 (CCK-8) assay, colony formation assays and flow cytometry. Quantitative real-time polymerase chain reaction (qRT‒PCR), western blotting, immunohistochemistry, immunofluorescence and Co-immunoprecipitation (Co-IP) were used to assess the molecular changes and regulation. The therapeutic efficacy of BRC and FGFR4 inhibitor fisogatinib (FISO) combination was evaluated in drug-resistant cells and xenograft tumors in nude mice.

RESULTS

Consistent with the preliminary results of RNA sequencing and database screening, fibroblast growth factor 19 (FGF19) expression was elevated in drug-resistant cells and tumor samples. With FGF19 silencing, drug-resistant cells exhibited increased sensitivity to BRC and decreased intracellular phosphorylated fibroblast growth factor receptor 4 (FGFR4) levels. After confirming that FGF19 binds to FGFR4 in prolactinoma cells, we found that FGF19/FGFR4 regulated prolactin (PRL) synthesis through the ERK1/2 and JNK signaling pathways. Regarding the effect of targeting FGF19/FGFR4 on BRC efficacy, FISO and BRC synergistically inhibited the growth of tumor cells, promoted apoptosis and reduced PRL levels.

CONCLUSION

Overall, our study revealed FGF19/FGFR4 as a new mechanism involved in the drug resistance of prolactinomas, and combination therapy targeting the pathway could be helpful for the treatment of BRC-induced drug-resistant prolactinomas.

Clinical, pathological and gene expression profiling of estrogen receptor discordance in breast cancer

BACKGROUND

Breast cancer (BC) is the world's largest tumor species in which hormone receptor-positive patients have relatively good prognosis. However, majority of patients will develop late resistance, one of the important factors is due to the loss of the original estrogen receptor (ER) expression.

METHODS

We conducted this study in 115 patients with BC who experienced second biopsy at Jiangsu Province Hospital (JSPH) and divided patients into two subgroups ER + to - and ER + to + . First, clinicopathological characteristics between two groups were evaluated. Second, we explored candidate genes related to BC ER intratumor heterogeneity by applying next-generation sequencing (NGS) in 42 patients. Multi-omics integrative analysis of tumor transcriptomic, cancer-related pathway, diagnostic and prognostic value and immune profile were conducted. Besides, preliminary assay were also used to evaluate the correlation between KMT2C and ERα (ESR1) expression. The CCK-8, 5-Ethynyl-2'-deoxyuridine (EdU) assays, Transwell assays and the wound scratch tests were applied to explore the cellular interactions between KMT2C and BC.

RESULTS

We find the histological type (p = 0.008) and disease-free survival (DFS) (p = 0.004) were significantly different in two subgroups. In Cox survival analysis, metastasis (Hazard ratio (HR) > 1, p = 0.007) and neo-adjuvant (HR < 1, p < 0.001) are independent prognostic factors of DFS. Besides, by analyzing NGS results, we found four genes KMT2C, FGFR19, FGF1 and FGF4 were highly mutated genes in ER + to - subgroup. Furthermore, the gene KMT2C displayed significant diagnostic value and prognostic value in BC and pan-cancer. In addition, a positive correlation between KMT2C expression and immune infiltrating levels of T cell CD4 + , macrophage and neutrophil was found. In the end, Western blot and RT-qPCR assay were used and found KMT2C and ERα (ESR1) expressions are strongly positive correlated in mRNA and protein level. Inhibition of KMT2C significantly reduced proliferation, invasion, and migration of MCF7 cells.

CONCLUSION

People in two cohorts from JSPH presented different clinical characteristics and prognosis. The gene KMT2C may affect the progression of BC by regulating the molecular, epigenetic activity and immune infiltration. It may also serve as a novel prognostic biomarker for BC patients who underwent ER status converted from positive to negative.

Evaluation of different media compositions promoting hepatocyte differentiation in the canine liver organoid model

Organoids are 3-dimensional (3D) self-assembled structures capable of replicating the microanatomy and physiology of the epithelial components of their organ of origin. Adult stem cell (ASC) derived organoids from the liver have previously been shown to differentiate into primarily mature cholangiocytes, and their partial differentiation into functional hepatocytes can be promoted using specific media compositions. While full morphological differentiation of mature hepatocytes from ASCs has not yet been reported for any species, the functional differentiation can be approximated using various media compositions. Six differentiation media formulations from published studies on hepatic organoids were used for the differentiation protocol. Target species for these protocols were humans, mice, cats, and dogs, and encompassed various combinations and concentrations of four major hepatocyte media components: Bone morphogenetic protein 7 (BMP7), Fibroblast Growth Factor 19 (FGF19), Dexamethasone (Dex), and Gamma-Secretase Inhibitor IX (DAPT). Additionally, removing R-spondin from basic organoid media has previously been shown to drive the differentiation of ASC into mature hepatocytes. Differentiation media (N = 20) were designed to encompass combinations of the four major hepatocyte media components. The preferred differentiation of ASC-derived organoids from liver tissue into mature hepatocytes over cholangiocytes was confirmed by albumin production in the culture supernatant. Out of the twenty media compositions tested, six media resulted in the production of the highest amounts of albumin in the supernatant of the organoids. The cell lines cultured using these six media were further characterized via histological staining, transmission electron microscopy, RNA in situ hybridization, analysis of gene expression patterns, immunofluorescence, and label-free proteomics. The results indicate that preferential hepatocyte maturation from canine ADC-derived organoids from liver tissue is mainly driven by Dexamethasone and DAPT components. FGF19 did not enhance organoid differentiation but improved cell culture survival. Furthermore, we confirm that removing R-spondin from the media is crucial for establishing mature hepatic organoid cultures.

Nicotinic acetylcholine receptor CHRNA5 is overexpressed in head and neck squamous cell carcinoma patients with a recent tobacco smoking history

Tobacco smoking is a major driver of head and neck squamous cell carcinoma (HNSCC) occurrence, and previous studies have shed light on the precise molecular alterations in tobacco-related HNSCCs when compared to HNSCCs associated with other risk factors (ex: human papillomavirus/HPV status). In this study, we analyzed the gene expression differences in HNSCC cases with a recent smoking history and revealed that the nicotinic acetylcholine receptor CHRNA5 is differentially overexpressed in smoking-related HNSCCs. CHRNA5 overexpression in these HNSCCs corresponds with a worse prognosis and is inversely correlated with an immune expression signature commonly associated with better prognosis. From these results, our study highlights the potential role of the nicotine-activated CHRNA5 receptor in HNSCC progression and corresponds with other recent reports highlighting the potential role of nicotine induction in promoting cancer progression.

Fibroblast growth factor receptor-4 mediates activation of Nuclear Factor Erythroid 2-Related Factor-2 in gastric tumorigenesis

Helicobacter pylori (H. pylori) is the leading risk factor for gastric carcinogenesis. Fibroblast growth factor receptor 4 (FGFR4) is a member of transmembrane tyrosine kinase receptors that are activated in cancer. We investigated the role of FGFR4 in regulating the cellular response to H. pylori infection in gastric cancer. High levels of oxidative stress signature and FGFR4 expression were detected in gastric cancer samples. Gene set enrichment analysis (GSEA) demonstrated enrichment of NRF2 signature in samples with high FGFR4 levels. H. pylori infection induced reactive oxygen species (ROS) with a cellular response manifested by an increase in FGFR4 with accumulation and nuclear localization NRF2. Knocking down FGFR4 significantly reduced NRF2 protein and transcription activity levels, leading to higher levels of ROS and DNA damage following H. pylori infection. We confirmed the induction of FGFR4 and NRF2 levels using mouse models following infection with a mouse-adapted H. pyloristrain. Pharmacologic inhibition of FGFR4 using H3B-6527, or its knockdown, remarkably reduced the level of NRF2 with a reduction in the size and number of gastric cancer spheroids. Mechanistically, we detected binding between FGFR4 and P62 proteins, competing with NRF2-KEAP1 interaction, allowing NRF2 to escape KEAP1-dependent degradation with subsequent accumulation and translocation to the nucleus. These findings demonstrate a novel functional role of FGFR4 in cellular homeostasis via regulating the NRF2 levels in response to H. pylori infection in gastric carcinogenesis, calling for testing the therapeutic efficacy of FGFR4 inhibitors in gastric cancer models.

FGFR families: biological functions and therapeutic interventions in tumors

There are five fibroblast growth factor receptors (FGFRs), namely, FGFR1-FGFR5. When FGFR binds to its ligand, namely, fibroblast growth factor (FGF), it dimerizes and autophosphorylates, thereby activating several key downstream pathways that play an important role in normal physiology, such as the Ras/Raf/mitogen-activated protein kinase kinase/extracellular signal-regulated kinase, phosphoinositide 3-kinase (PI3K)/AKT, phospholipase C gamma/diacylglycerol/protein kinase c, and signal transducer and activator of transcription pathways. Furthermore, as an oncogene, FGFR genetic alterations were found in 7.1% of tumors, and these alterations include gene amplification, gene mutations, gene fusions or rearrangements. Therefore, FGFR amplification, mutations, rearrangements, or fusions are considered as potential biomarkers of FGFR therapeutic response for tyrosine kinase inhibitors (TKIs). However, it is worth noting that with increased use, resistance to TKIs inevitably develops, such as the well-known gatekeeper mutations. Thus, overcoming the development of drug resistance becomes a serious problem. This review mainly outlines the FGFR family functions, related pathways, and therapeutic agents in tumors with the aim of obtaining better outcomes for cancer patients with FGFR changes. The information provided in this review may provide additional therapeutic ideas for tumor patients with FGFR abnormalities.

SMURF1 attenuates endoplasmic reticulum stress by promoting the degradation of KEAP1 to activate NRF2 antioxidant pathway

Cancer cells consistently utilize the unfolded protein response (UPR) to encounter the abnormal endoplasmic reticulum (ER) stress induced by the accumulation of misfolded proteins. Extreme activation of the UPR could also provoke maladaptive cell death. Previous reports have shown that NRF2 antioxidant signaling is activated by UPR and serves as noncanonical pathway to defense and reduce excessive ROS levels during ER stress. However, the mechanisms of regulating NRF2 signaling upon ER stress in glioblastoma have not been fully elucidated. Here we identify that SMURF1 protects against ER stress and facilitates glioblastoma cell survival by rewiring KEAP1-NRF2 pathway. We show that ER stress induces SMURF1 degradation. Knockdown of SMURF1 upregulates IRE1 and PERK signaling in the UPR pathway and prevents ER-associated protein degradation (ERAD) activity, leading to cell apoptosis. Importantly, SMURF1 overexpression activates NRF2 signaling to reduce ROS levels and alleviate UPR-mediated cell death. Mechanistically, SMURF1 interacts with and ubiquitinates KEAP1 for its degradation (NRF2 negative regulator), resulting in NRF2 nuclear import. Moreover, SMURF1 loss reduces glioblastoma cell proliferation and growth in subcutaneously implanted nude mice xenografts. Taken together, SMURF1 rewires KEAP1-NRF2 pathway to confer resistance to ER stress inducers and protect glioblastoma cell survival. ER stress and SMURF1 modulation may provide promising therapeutic targets for the treatment of glioblastoma.

Loss of Ufl1/Ufbp1 in hepatocytes promotes liver pathological damage and carcinogenesis through activating mTOR signaling

BACKGROUND

Ufm1-specific ligase 1 (Ufl1) and Ufm1-binding protein 1 (Ufbp1), as putative targets of ubiquitin-fold modifier 1 (Ufm1), have been implicated in several pathogenesis-related signaling pathways. However, little is known about their functional roles in liver disease.

METHODS

Hepatocyte-specific Ufl1^Δ/Δhep and Ufbp1^Δ/Δhep mice were used to study their role in liver injury. Fatty liver disease and liver cancer were induced by high-fat diet (HFD) and diethylnitrosamine (DEN) administration, respectively. iTRAQ analysis was employed to screen for downstream targets affected by Ufbp1 deletion. Co-immunoprecipitation was used to determine the interactions between the Ufl1/Ufbp1 complex and the mTOR/GβL complex.

RESULTS

Ufl1^Δ/Δhep or Ufbp1^Δ/Δhep mice exhibited hepatocyte apoptosis and mild steatosis at 2 months of age and hepatocellular ballooning, extensive fibrosis, and steatohepatitis at 6-8 months of age. More than 50% of Ufl1^Δ/Δhep and Ufbp1^Δ/Δhep mice developed spontaneous hepatocellular carcinoma (HCC) by 14 months of age. Moreover, Ufl1^Δ/Δhep and Ufbp1^Δ/Δhep mice were more susceptible to HFD-induced fatty liver and DEN-induced HCC. Mechanistically, the Ufl1/Ufbp1 complex directly interacts with the mTOR/GβL complex and attenuates mTORC1 activity. Ablation of Ufl1 or Ufbp1 in hepatocytes dissociates them from the mTOR/GβL complex and activates oncogenic mTOR signaling to drive HCC development.

CONCLUSIONS

These findings reveal the potential role of Ufl1 and Ufbp1 as gatekeepers to prevent liver fibrosis and subsequent steatohepatitis and HCC development by inhibiting the mTOR pathway.

From Non-Alcoholic Fatty Liver to Hepatocellular Carcinoma: A Story of (Mal)Adapted Mitochondria

Non-alcoholic fatty liver disease (NAFLD) is a global pandemic affecting 25% of the world's population and is a serious health and economic concern worldwide. NAFLD is mainly the result of unhealthy dietary habits combined with sedentary lifestyle, although some genetic contributions to NAFLD have been documented. NAFLD is characterized by the excessive accumulation of triglycerides (TGs) in hepatocytes and encompasses a spectrum of chronic liver abnormalities, ranging from simple steatosis (NAFL) to steatohepatitis (NASH), significant liver fibrosis, cirrhosis, and hepatocellular carcinoma. Although the molecular mechanisms that cause the progression of steatosis to severe liver damage are not fully understood, metabolic-dysfunction-associated fatty liver disease is strong evidence that mitochondrial dysfunction plays a significant role in the development and progression of NAFLD. Mitochondria are highly dynamic organelles that undergo functional and structural adaptations to meet the metabolic requirements of the cell. Alterations in nutrient availability or cellular energy needs can modify mitochondria formation through biogenesis or the opposite processes of fission and fusion and fragmentation. In NAFL, simple steatosis can be seen as an adaptive response to storing lipotoxic free fatty acids (FFAs) as inert TGs due to chronic perturbation in lipid metabolism and lipotoxic insults. However, when liver hepatocytes' adaptive mechanisms are overburdened, lipotoxicity occurs, contributing to reactive oxygen species (ROS) formation, mitochondrial dysfunction, and endoplasmic reticulum (ER) stress. Impaired mitochondrial fatty acid oxidation, reduction in mitochondrial quality, and disrupted mitochondrial function are associated with a decrease in the energy levels and impaired redox balance and negatively affect mitochondria hepatocyte tolerance towards damaging hits. However, the sequence of events underlying mitochondrial failure from steatosis to hepatocarcinoma is still yet to be fully clarified. This review provides an overview of our understanding of mitochondrial adaptation in initial NAFLD stages and highlights how hepatic mitochondrial dysfunction and heterogeneity contribute to disease pathophysiology progression, from steatosis to hepatocellular carcinoma. Improving our understanding of different aspects of hepatocytes' mitochondrial physiology in the context of disease development and progression is crucial to improving diagnosis, management, and therapy of NAFLD/NASH.

Current, emerging, and potential therapies for non-alcoholic steatohepatitis

Non-alcoholic fatty liver disease (NAFLD) has been identified as the most common chronic liver disease worldwide, with a growing incidence. NAFLD is considered the hepatic manifestation of a metabolic syndrome that emerges from multiple factors (e.g., oxidative stress, metabolic disorders, endoplasmic reticulum stress, cell death, and inflammation). Non-alcoholic steatohepatitis (NASH), an advanced form of NAFLD, has been reported to be a leading cause of cirrhosis and hepatic carcinoma, and it is progressing rapidly. Since there is no approved pharmacotherapy for NASH, a considerable number of therapeutic targets have emerged with the deepening of the research on NASH pathogenesis. In this study, the therapeutic potential and properties of regulating metabolism, the gut microbiome, antioxidant, microRNA, inhibiting apoptosis, targeting ferroptosis, and stem cell-based therapy in NASH are reviewed and evaluated. Since the single-drug treatment of NASH is affected by individual heterogeneous responses and side effects, it is imperative to precisely carry out targeted therapy with low toxicity. Lastly, targeted therapeutic agent delivery based on exosomes is proposed in this study, such that drugs with different mechanisms can be incorporated to generate high-efficiency and low-toxicity individualized medicine.

FGF-23 protects cell function and viability in murine pancreatic islets challenged by glucolipotoxicity

The fibroblast growth factor FGF-23 is a member of the FGF-15/19 subfamily with hormonal functions. Besides its well-known role for bone mineralization, FGF-23 is discussed as a marker for cardiovascular disease. We investigated whether FGF-23 has any effects on the endocrine pancreas of mice by determining insulin secretion, electrical activity, intracellular Ca2+, and apoptosis. Acute application of FGF-23 (10 to 500 ng/ml, i.e., 0.4 to 20 nM) does not affect insulin release of murine islets, while prolonged exposure leads to a 21% decrease in glucose-stimulated secretion. The present study shows for the first time that FGF-23 (100 or 500 ng/ml) partially protects against impairment of insulin secretion and apoptotic cell death induced by glucolipotoxicity. The reduction of apoptosis by FGF-23 is approximately twofold higher compared to FGF-21 or FGF-15/19. In contrast to FGF-23 and FGF-21, FGF-15/19 is clearly pro-apoptotic under control conditions. The beneficial effect of FGF-23 against glucolipotoxicity involves interactions with the stimulus-secretion cascade of beta-cells. Electrical activity and the rise in the cytosolic Ca2+ concentration of islets in response to acute glucose stimulation increase after glucolipotoxic culture (48 h). Co-culture with FGF-23 further elevates the glucose-mediated effects on both parameters. Protection against apoptosis and glucolipotoxic impairment of insulin release by FGF-23 is prevented, when calcineurin is inhibited by tacrolimus or when c-Jun N-terminal kinase (JNK) is blocked by SP600125. In conclusion, our data suggest that FGF-23 can activate compensatory mechanisms to maintain beta-cell function and integrity of islets of Langerhans during excessive glucose and lipid supply.

FGF19 promotes cell autophagy and cisplatin chemoresistance by activating MAPK signaling in ovarian cancer

Background

Chemotherapy is one of the primary treatments for ovarian cancer patients. Autophagy has been linked to chemotherapy resistance in tumor cells. Recent studies have suggested that fibroblast growth factor 19 (FGF19) may be involved in the onset and progression of malignancies. However, the relationship between FGF19 and autophagy in ovarian cancer is still unknown.

Methods

Next-generation sequencing (NGS) was conducted to analyze gene mutation profiles of 62 cases of high grade serous ovarian cancer (HGSOC). Fluorescence in situ hybridization (FISH) was performed to validate the amplification of FGF19 in HGSOC tissues. Quantitative PCR (qPCR) and immunohistochemistry (IHC) were used to analyze the difference of FGF19 in mRNA and protein expression. Meanwhile, bioinformatics techniques were used to analyze the expression profiles of FGF19 and the correlation with prognosis. Besides, immunofluorescence, transmission electron microscopy and Cell Counting Kit 8 (CCK-8) were used to investigate the potential mechanisms.

Results

In this study, we found that FGF19 promotes cisplatin resistance in ovarian cancer cells by inducing autophagy. NGS analysis of 62 HGSOC cases identified a significantly amplified gene, FGF19. In addition, the expression level of FGF19 in ovarian cancer samples was higher than that in normal samples. FISH results showed a positive correlation between amplification and expression of FGF19. Knockdown of FGF19 inhibited the cell autophagy through decrease in the expression of LC3 and Beclin 1, and increase in the expression of SQSTM1/p62. Furthermore, we observed that p38 MAPK phosphorylation was down-regulated after FGF19 knockdown. IFN-γ, a potential p38 MAPK activator, counteracted the inhibition of cell autophagy and the anti-proliferation effect of cisplatin induced by FGF19 knockdown in ovarian cancer cells.

Conclusion

FGF19 increases autophagy and chemoresistance in ovarian cancer by activating the p38 MAPK pathway. These results could point to FGF19 being a potential therapeutic target for ovarian cancer.

Role of Nrf2 signaling in development of hepatocyte-like cells

Generation of hepatocytes from human adipose-derived mesenchymal stem cells (hADSCs) could be a promising alternative source of human hepatocytes. However, mechanisms to differentiate hepatocytes from hADSCs are not fully elucidated. We have previously demonstrated that our three-step differentiation protocol with glycogen synthase kinase (GSK) 3 inhibitor was effective to improve hepatocyte functions. In this study, we investigated the activation of the nuclear factor erythroid-2 related factor 2 (Nrf2) on hADSCs undergoing differentiation to HLC (hepatocyte-like cells). Our three-step differentiation protocol was applied for 21 days (Step 1:day 1-6, Step2:day 6-11, Step3:day 11-21). Our results show that significant nuclear translocation of Nrf2 occurred from day 11 until the end of HLC differentiation. Nuclear translocation of Nrf2 and CYP3A4 activity in the GSK3 inhibitor-treated group was obviously higher than that in Activin A-treated groups at day 11. The maturation of HLCs was delayed in Nrf2-siRNA group compared to control group. Furthermore, CYP3A4 activity in Nrf2-siRNA group was decreased at the almost same level in Activin A-treated group. Nrf2 translocation might enhance the function of HLC and be a target for developing highly functional HLC. J. Med. Invest. 70 : 343-349, August, 2023.

FGF15 promotes hepatic NPC1L1 degradation in lithogenic diet-fed mice

BACKGROUND

Cholesterol gallstone disease (CGD) is accompanied by biliary cholesterol supersaturation. Hepatic Niemann-Pick C1-like 1 (NPC1L1), which is present in humans but not in wild-type (WT) mice, promotes hepatocyte cholesterol uptake and decreases biliary cholesterol supersaturation. In contrast, intestinal NPC1L1 promotes intestinal cholesterol absorption, increasing biliary cholesterol supersaturation. Ezetimibe (EZE) can inhibit both hepatic and intestinal NPC1L1. However, whether hepatic NPC1L1 can affect CGD progress remains unknown.

METHODS

Mice expressing hepatic NPC1L1 (NPC1L1^hepatic-OE mice) were generated using Adeno-associated viruses (AAV) gene delivery. The protein level and function of hepatic NPC1L1 were examined under chow diet, high fat-cholesterol diet (HFCD), and lithogenic diet (LD) feeding. Gallstone formation rates were examined with or without EZE treatment. Fibroblast growth factor 15 (FGF15) treatment and inhibition of fibroblast growth factor receptor 4 (FGFR4) were applied to verify the mechanism of hepatic NPC1L1 degradation.

RESULTS

The HFCD-fed NPC1L1^hepatic-OE mice retained the biliary cholesterol desaturation function of hepatic NPC1L1, whereas EZE treatment decreased biliary cholesterol saturation and did not cause CGD. The ubiquitination and degradation of hepatic NPC1L1 were discovered in LD-fed NPC1L1^hepatic-OE mice. Treatment of FGF15 during HFCD feeding and inhibition of FGFR4 during LD feeding could affect the protein level and function of hepatic NPC1L1.

CONCLUSIONS

LD induces the ubiquitination and degradation of hepatic NPC1L1 via the FGF15-FGFR4 pathway. EZE may act as an effective preventative agent for CGD.

The role of fibroblast growth factor 19 in the pathogenesis of nonalcoholic fatty liver disease

INTRODUCTION

Nonalcoholic fatty liver disease (NAFLD) has emerged as the predominant cause of chronic liver injury worldwide. Bile acids and their receptors are profoundly implicated in the pathogenesis of NAFLD and its progression to nonalcoholic steatohepatitis and cirrhosis.

AREAS COVERED

We conducted extensive literature search using PubMed database, and we summarized the relevant literature. We provided an overview of the fibroblast growth factor 19 (FGF-19)-farnesoid X receptor (FXR) axis and summarized the latest findings derived from animal and human studies concerning the impact of FGF-19 on NAFLD.

EXPERT OPINION

FGF-19, a nutritionally regulated endocrine post-prandial hormone, governs bile acid metabolism, lipid oxidation, lipogenesis, and energy homeostasis. As no approved medication for NAFLD exists, FGF-19 seems to be a propitious therapeutic opportunity for NAFLD, since its administration was associated with ameliorated results in hepatic steatosis, liver inflammation and fibrosis. Furthermore, promising results have been derived from clinical trials concerning the beneficial efficacy of FGF-19 on histological findings and laboratory parameters of NAFLD. However, we should bear in mind the pleiotropic effects of FGF-19 on various metabolically active tissues along with its potential tumorigenic reservoir. Further clinical research is required to determine the clinical application of FGF-19-based therapies on NAFLD.

Physiological and pathophysiological role of endocrine fibroblast growth factors

The endocrine subfamily of fibroblast growth factors (FGF) includes three factors: FGF19, FGF21, FGF23. They act on distal tissues through FGF receptors (FGFRs). The FGFR activation requires two cofactors: α- and β-Klotho, which are structurally related single-pass transmembrane proteins. The endocrine FGFs regulate various metabolic processes involved in the regulation of glucose and lipid metabolism as well as bile acid circulation, vitamin D modulation, and phosphate homeostasis. The FGF-FGFR dysregulation is widely implicated in the pathogenesis of various disorders. Significant alterations in plasma FGF concentration are associated with the most prevalent chronic diseases, including dyslipidemia, type 2 diabetes, cardiovascular diseases, obesity, non-alcoholic fatty liver disease, diseases of the biliary tract, chronic kidney disease, inflammatory bowel disease, osteomalacia, various malignancies, and depression. Therefore, the endocrine FGFs may serve as disease predictors or biomarkers, as well as potential therapeutic targets. Currently, numerous analogues and inhibitors of endocrine FGFs are under development for treatment of various disorders, and recently, a human monoclonal antibody against FGF23 has been approved for treatment of X-linked hypophosphatemia. The aim of this review is to summarize the current data on physiological and pathophysiological actions of the endocrine FGF subfamily and recent research concerning the therapeutic potential of the endocrine FGF pathways.

DCZ0415, a small-molecule inhibitor targeting TRIP13, inhibits EMT and metastasis via inactivation of the FGFR4/STAT3 axis and the Wnt/β-catenin pathway in colorectal cancer

Thyroid receptor-interacting protein 13 (TRIP13), a protein of the AAA-ATPase family, is upregulated in various human cancers, including colorectal cancer (CRC). This study focused on the inhibition of TRIP13-induced CRC progression and signalling by DCZ0415, a small molecule targeting TRIP13. It demonstrated potent antitumour activity in TRIP13-deregulated cancer cell lines, regardless of their p53, KRAS, BRAF, epidermal growth factor receptor or microsatellite instability status. The treatment of CRC cells with DCZ0415 resulted in decreased cell proliferation, induced cell cycle arrest in the G2-M phase and increased apoptosis. DCZ0415 diminished xenograft tumour growth and metastasis of CRC in immunocompromised mice. DCZ0415 reduced expression of fibroblast growth factor receptor 4 (FGFR4), signal transducer and activator of transcription 3 (STAT3), and proteins associated with the epithelial-mesenchymal transition and nuclear factor kappa B (NF-κB) pathways in cells and xenografts exhibiting high expression of TRIP13. Additionally, DCZ0415 decreased cyclin D1, β-catenin and T-cell factor 1, leading to the inactivation of the Wnt/β-catenin pathway. In a syngeneic CRC model, DCZ0415 treatment induced an immune response by decreasing PD1 and CTLA4 levels and increasing granzyme B, perforin and interferon gamma. In sum, DCZ04145 inhibits the TRIP13-FGFR4-STAT3 axis, inactivates NF-κB and Wnt/β-catenin signalling, activates antitumour immune response and reduces the progression and metastasis of CRC. This study provides a rationale to evaluate DCZ0415 clinically for the treatment of a subset of CRCs that exhibit dysregulated TRIP13 and FGFR4.

CRISPR-Cas9-based genome-wide screening identified novel targets for treating sorafenib-resistant hepatocellular carcinoma: a cross-talk between FGF21 and the NRF2 pathway

The treatment of hepatocellular carcinoma (HCC) has been dominated by multikinase inhibitors for more than a decade. However, drug resistance can severely restrict the efficacy of these drugs. Using CRISPR/CAS9 genome library screening, we evaluated Kelch-like ECH-associated protein 1 (KEAP1) as a key regulator of sorafenib's susceptibility in HCC. We also investigated whether KEAP1's knockdown can stabilize nuclear factor (erythroid-derived 2)-like 2 (NRF2) protein levels that led to sorafenib's resistance, including an NRF2 inhibitor that can synergize with sorafenib to abolish HCC's growth in vitro and in vivo. Furthermore, we clarified that fibroblast growth factor 21 (FGF21) is an important downstream regulator of NRF2 in HCC. Intriguingly, we observed that FGF21 bound to NRF2 through the C-terminus of FGF21, thereby stabilizing NRF2 by reducing its ubiquitination and generating a positive feedback loop in sorafenib-resistant HCC. These findings, therefore, propose that targeting FGF21 is a promising strategy to combat HCC sorafenib's resistance.

Nuclear Localization of Fibroblast Growth Factor Receptor 1 in Breast Cancer Cells Interacting with Cancer Associated Fibroblasts

Cancer-associated fibroblasts (CAFs) represent a major component of the tumor microenvironment and interplay with cancer cells by secreting cytokines, growth factors and extracellular matrix proteins. When estrogen receptor-negative breast cancer MDA-MB-231 cells were treated with the CAF-conditioned medium (CAF-CM), Akt and STAT3 involved in cell proliferation and survival were activated through phosphorylation. CAFs secrete fibroblast growth factor 2 (FGF2), thereby stimulating breast cancer cell progression. Akt activation induced by CAF-CM in MDA-MB-231 cells was abolished when FGF2-neutralizing antibody was added. Treatment of MDA-MB-231 cells directly with FGF2 enhanced the phosphorylation of Akt and the FGF receptor (FGFR) substrate, FRS2α. These events were abrogated by siRNA-mediated silencing of FGFR1. In a xenograft mouse model, co-injection of MDA-MB-231 cells with activated fibroblasts expressing FGF2 dramatically enhanced activation of Akt. Stable knockdown of FGFR1 blunted Akt phosphorylation in xenograft tumors. MDA-MB-231 cells co-cultured with CAFs or directly stimulated with FGF2 exhibited enhanced nuclear localization of FGFR1. Notably, FGF2 stimulation produced reactive oxygen species (ROS) accumulation in MDA-MB-231 cells, and FGF2-induced nuclear accumulation of FGFR1 was abrogated by the ROS scavenging agent, N-acetylcysteine.

Assessment of fibroblast growth factor 19 as a non-invasive serum marker for hepatocellular carcinoma

BACKGROUND

Fibroblast growth factor 19 (FGF-19) is one of the founding members of the endocrine FGF subfamily. Recently, it has been the subject of much interest owing to its role in various physiological processes affecting glucose and lipid metabolism and the regulation of bile acid secretion as well as cell proliferation, differentiation, and motility. Additionally, FGF-19 secretion in an autocrine style has reportedly contributed to cancer progression in various types of malignancies including hepatocellular carcinoma (HCC).

AIM

To estimate the serum FGF-19 concentrations in HCC cases and assess its diagnostic performance for the detection of HCC.

METHODS

We recruited 90 adult participants and divided them into three equal groups: Healthy controls, cirrhosis patients, and HCC patients. Serum FGF-19 concentrations were measured using the Human FGF-19 ELISA kit.

RESULTS

We detected a high statistically significant difference in serum FGF-19 levels among the three groups. The highest level was observed in the HCC group, followed by the cirrhosis and control groups (236.44 ± 40.94 vs 125.63 ± 31.54 vs 69.60 ± 20.90 pg/mL, respectively, P ≤ 0.001). FGF-19 was positively correlated with alpha fetoprotein (AFP; r = 0.383, P = 0.003) and international normalised ratio (r = 0.357, P = 0.005), while it was negatively correlated with albumin (r = -0.500, P ≤ 0.001). For the detection of HCC, receiver operating characteristic curve analysis showed that the best cut-off point of AFP was > 8.2 ng/mL with an area under the curve (AUC) of 0.78, sensitivity of 63.33%, specificity of 83.33%, positive predictive value (PPV) of 79.2%, negative predictive value (NPV) of 69.4%, and total accuracy of 78%. However, FGF-19 at a cut-off point > 180 pg/mL had an AUC of 0.98, sensitivity of 100%, specificity of 90.0%, PPV of 90.0%, NPV of 100%, and total accuracy of 98%.

CONCLUSION

FGF-19 represents a possible novel non-invasive marker for HCC. It may improve the prognosis of HCC patients due to its utility in several aspects of HCC detection and management.

GPX2 is a potential therapeutic target to induce cell apoptosis in lenvatinib against hepatocellular carcinoma

INTRODUCTION

Lenvatinib has recently become available as the first-line therapy for advanced hepatocellular carcinoma (HCC), but its molecular mechanism in HCC remains largely unknown.

OBJECTIVES

The current study aims to identify the molecular mechanisms of lenvatinib in HCC.

METHODS

Gene expression microarrays, flow cytometry, western blot, qRT-PCR, immunohistochemistry and immunofluorescence were used to study the response of HCC cells to lenvatinib. Xenograft tumor of Huh7 cells was also established to detect the effect of lenvatinib in vivo.

RESULTS

Herein, we found that lenvatinib could induce apoptosis via increasing reactive oxygen species (ROS) levels in HCC cells. Then, microarray analysis and qRT-PCR results confirmed that GPX2 was a vital target for lenvatinib against HCC. Loss and gain function of experiment showed that regulating GPX2 levels markedly affected the lenvatinib-induced ROS levels and apoptosis in HCC cells. In addition, analyses of The Cancer Genome Atlas database and the qRT-PCR results in our cohort both showed that GPX2 markedly overexpressed in tumor tissues and correlated with poor overall survival in HCC. Mechanistically, our findings further demonstrated that GPX2 was a downstream gene regulated by β-catenin, while lenvatinib could prevent nuclear translocation of β-catenin and further inhibit GPX2 expression in HCC cells. More importantly, the correlation of GPX2 expression with lenvatinib response was further analyzed in 22 HCC patients who received lenvatinib therapy, and the results showed that the objective response rate (ORR) in patients with low GPX2 expression was 44.4% (4/9), while the ORR in patients with high GPX2 levels was only 7.7% (1/13).

CONCLUSION

Our findings indicated that GPX2 plays an important role in lenvatinib-induced HCC cell apoptosis, which might serve as a biomarker for instruction of lenvatinib therapy in HCC patients.

Knockdown of AKR1C3 Promoted Sorafenib Sensitivity Through Inhibiting the Phosphorylation of AKT in Hepatocellular Carcinoma

Background

Sorafenib, which can induce ferroptosis, is a multikinase inhibitor for enhancing survival in advanced hepatocellular carcinoma (HCC). However, a considerable challenge for the treatment of HCC is sorafenib resistance. Therefore, targeting the relationship between sorafenib resistance and ferroptosis genes may provide a novel approach for the treatment of HCC.

Materials and Methods

We analyzed the gene expression and clinicopathological factors from The Cancer Genome Atlas Liver Hepatocellular Carcinoma (TCGA-LIHC), International Cancer Genome Consortium (ICGC), and Gene Expression Omnibus (GEO) databases (GSE109211/GSE62813). The statistical analysis was conducted in R. Cell proliferation was assayed by MTT, cell colony-forming assay, and wound healing assay. Immunofluorescence assay and Western blot were used to evaluate the expression of AKT.

Results

Many ferroptosis-related genes were upregulated in the sorafenib-resistant group. Aldo-keto reductase 1C3 (AKR1C3) was highly expressed in sorafenib-resistant patients, and the high expression of AKR1C3 was associated with the poor prognosis of patients from the TCGA and ICGC databases. MTT and colony-forming assays showing AKR1C3 overexpression enhanced the proliferation of HCC cells and acute sorafenib resistance. Knockdown of AKR1C3 inhibited the proliferation of HCC cells and increased the drug sensitivity of sorafenib. Immunofluorescence assay and Western blot proved that AKR1C3 promoted the phosphorylation of AKT.

Conclusion

AKR1C3 can induce sorafenib resistance through promoting the phosphorylation of AKT in HCC. AKR1C3 inhibitors may be used in conjunction with sorafenib to become a better therapeutic target for HCC.

Endocrine Fibroblast Growth Factors in Relation to Stress Signaling

Fibroblast growth factors (FGFs) play important roles in various growth signaling processes, including proliferation, development, and differentiation. Endocrine FGFs, i.e., atypical FGFs, including FGF15/19, FGF21, and FGF23, function as endocrine hormones that regulate energy metabolism. Nutritional status is known to regulate the expression of endocrine FGFs through nuclear hormone receptors. The increased expression of endocrine FGFs regulates energy metabolism processes, such as fatty acid metabolism and glucose metabolism. Recently, a relationship was found between the FGF19 subfamily and stress signaling during stresses such as endoplasmic reticulum stress and oxidative stress. This review focuses on endocrine FGFs and the recent progress in FGF studies in relation to stress signaling. In addition, the relevance of the stress-FGF pathway to disease and human health is discussed.

Dark and bright side of targeting fibroblast growth factor receptor 4 in the liver

Fibroblast growth factor (FGF) receptor 4 (FGFR4) and its cognate ligand, FGF19, are implicated in a range of cellular processes, including differentiation, metabolism and proliferation. Indeed, their aberrant activation has been associated with the development of hepatic tumours. Despite great advances in early diagnosis and the development of new therapies, liver cancer is still associated with a high mortality rate, owing primarily to high molecular heterogeneity and unclear molecular targeting. The development of FGFR4 inhibitors is a promising tool in patients with concomitant supraphysiological levels of FGF19 and several clinical trials are testing these treatments for patients with advanced hepatocellular carcinoma (HCC). Conversely, using FGF19 analogues to activate FGFR4-KLOTHO β represents a novel therapeutic strategy in patients presenting with cholestatic liver disorders and non-alcoholic steatohepatitis, which could potentially prevent the development of metabolic HCC. Herein, we provide an overview of the currently available therapeutic options for targeting FGFR4 in HCC and other liver diseases, highlighting the need to carefully stratify patients and personalise therapeutic strategies.

FGF/FGFR-Dependent Molecular Mechanisms Underlying Anti-Cancer Drug Resistance

Simple Summary

Deregulation of the FGF/FGFR axis is associated with many types of cancer and contributes to the development of chemoresistance, limiting the effectiveness of current treatment strategies. There are several mechanisms involved in this phenomenon, including cross-talks with other signaling pathways, avoidance of apoptosis, stimulation of angiogenesis, and initiation of EMT. Here, we provide an overview of current research and approaches focusing on targeting components of the FGFR/FGF signaling module to overcome drug resistance during anti-cancer therapy.

Abstract

Increased expression of both FGF proteins and their receptors observed in many cancers is often associated with the development of chemoresistance, limiting the effectiveness of currently used anti-cancer therapies. Malfunctioning of the FGF/FGFR axis in cancer cells generates a number of molecular mechanisms that may affect the sensitivity of tumors to the applied drugs. Of key importance is the deregulation of cell signaling, which can lead to increased cell proliferation, survival, and motility, and ultimately to malignancy. Signaling pathways activated by FGFRs inhibit apoptosis, reducing the cytotoxic effect of some anti-cancer drugs. FGFRs-dependent signaling may also initiate angiogenesis and EMT, which facilitates metastasis and also correlates with drug resistance. Therefore, treatment strategies based on FGF/FGFR inhibition (using receptor inhibitors, ligand traps, monoclonal antibodies, or microRNAs) appear to be extremely promising. However, this approach may lead to further development of resistance through acquisition of specific mutations, metabolism switching, and molecular cross-talks. This review brings together information on the mechanisms underlying the involvement of the FGF/FGFR axis in the generation of drug resistance in cancer and highlights the need for further research to overcome this serious problem with novel therapeutic strategies.

Molecular mechanisms of hepatotoxic cholestasis by clavulanic acid: Role of NRF2 and FXR pathways

Treatment of β-lactamase positive bacterial infections with a combination of amoxicillin (AMOX) and clavulanic acid (CLAV) causes idiosyncratic drug-induced liver injury (iDILI) in a relevant number of patients, often with features of intrahepatic cholestasis. This study aims to determine serum bile acid (BA) levels in amoxicillin/clavulanate (A+C)-iDILI patients and to investigate the mechanism of cholestasis by A+C in human in vitro hepatic models. In six A+C-iDILI patients, significant elevations of serum primary conjugated BA definitely demonstrated A+C-induced cholestasis. In cultured human Upcyte hepatocytes and HepG2 cells, CLAV was more cytotoxic than AMOX, and, at subcytotoxic concentrations, it altered the expression of more than 1,300 genes. CLAV, but not AMOX, downregulated the expression of key genes for BA transport (BSEP, NTCP, OSTα and MDR2) and synthesis (CYP7A1 and CYP8B1). CLAV also caused early oxidative stress, with reduced GSH/GSSG ratio, along with induction of antioxidant nuclear factor erythroid 2-related factor 2 (NRF2) target genes. Activation of NRF2 by sulforaphane also resulted in downregulation of NTCP, OSTα, ABCG5, CYP7A1 and CYP8B1. CLAV also inhibited the BA-sensor farnesoid X receptor (FXR), in agreement with the downregulation of FXR targets BSEP, OSTα and ABCG5. We conclude that CLAV, the culprit molecule in A+C, downregulates several key biliary transporters by modulating NRF2 and FXR signaling, thus likely promoting intrahepatic cholestasis. On top of that, increased ROS production and GSH depletion may aggravate the cholestatic injury by A+C.

High concentration of serum FGF19 at ICU admission is associated with 28-day mortality in sepsis patients

BACKGROUND

Sepsis remains associated with a high mortality rate despite recent advances in treatment. Traditional biomarkers are inadequate for stratification of patients by sepsis severity. We examined use of the baseline concentration of fibroblast growth factor 19 (FGF19) in predicting 28-day mortality from sepsis.

METHODS

A total of 220 consecutive adult patients with sepsis who were admitted to our intensive care unit (ICU) during 2020 were prospectively recruited. Patients were categorized as survivors or non-survivors according to status at 28 days. Baseline concentrations of FGF19 and other parameters were measured. Receiver operating characteristic (ROC) analysis was used to determine the sensitivity, specificity, predictive value, and optimal cutoff of FGF19 in prediction of survival. Prognostic factors were identified using Cox regression analysis.

RESULTS

The serum FGF19 concentration was much higher in non-survivors than in survivors (355.0 pg/ml [range: 37.2, 2315.6] vs. 127.3 pg/ml [5.7, 944.1]; P < 0.05]. ROC analysis indicated an FGF19 concentration of 180 pg/ml was the optimal cutoff value. Multivariable Cox regression analysis showed that FGF19 concentration and the change in sequential organ failure assessment (ΔSOFA) score at baseline were independently and significantly associated with 28-day mortality. ROC analysis indicated that FGF19 had a better predictive value than PCT or CRP. Although ΔSOFA had a better predictive value than FGF19, ΔSOFA and FGF19 together had a significantly better predictive value than ΔSOFA alone.

CONCLUSION

Sepsis patients with high serum concentrations of FGF19 at ICU admission were associated with an increased risk of 28-day mortality in our ICU.

Endoplasmic reticulum stress: Multiple regulatory roles in hepatocellular carcinoma

BACKGROUND

Endoplasmic reticulum (ER) stress is a basic cellular stress response that maintains cellular protein homeostasis under endogenous or exogenous stimuli, which depends on the stimulus, its intensity, and action time. The ER produces a corresponding cascade reaction for crosstalk of adaptive and/or pro-death regulation with other organelles. Hepatocellular carcinoma(HCC) is one of the most common malignant solid tumors with an extremely poor prognosis. Viral hepatitis infection, cirrhosis, and steatohepatitis are closely related to the occurrence and development of HCC, and ER stress has gradually been shown to be a major mechanism. Moreover, an increasing need for protein and lipid products and relative deficiencies of oxygen and nutrients for rapid proliferation and endoplasmic reticulum stress are undoubtedly involved. Therefore, to fully and comprehensively understand the regulatory role of endoplasmic reticulum stress in the occurrence and progression of HCC is of vital importance to explore its pathogenesis and develop novel anti-cancer strategies.

METHODOLOGY

We searched for relevant publications in the PubMed databases using the keywords "Endoplasmic reticulum stress", "hepatocellular carcinoma" in last five years,and present an overview of the current knowledge that links ER stress and HCC, which includes carcinogenesis, progression, and anti-cancer strategies, and propose directions of future research.

RESULT

ER stress were confirmed to be multiple regulators or effectors of cancer, which also be confirmed to drive tumorigenesis and progression of HCC. Targeting ER stress signaling pathway and related molecules could play a critical role for anti-HCC and has become a research hotspot for anti-cancer in recent years.

CONCLUSION

ER stress are critical for the processes of the tumorigenesis and progression of tumors. For HCC, ER stress was associated with tumorigenesis, development, metastasis, angiogenesis and drug resistance, targeting ER stress has emerged as a potential anti-tumor strategy.

Aberrant FGFR4 signaling worsens nonalcoholic steatohepatitis in FGF21KO mice

Background: Nonalcoholic steatohepatitis (NASH) is the most severe form of non-alcoholic fatty liver disease (NAFLD) and a potential precursor of hepatocellular carcinoma (HCC). In our previous studies, we found that endocrine fibroblast growth factor 21 (FGF21) played a key role in preventing the development of NASH, however, the FGF15/19 mediated-FGFR4 signaling worsened NASH and even contributed to the NASH-HCC transition. The aim of this study is to determine whether FGF15/FGFR4 signaling could alleviate or aggravate NASH in the FGF21KO mice.

Methods: NASH models were established in FGF21KO mice fed with high fat methionine-choline deficient (HFMCD) diet to investigate FGF15/FGFR4 signaling during early stage NASH and advanced stage NASH. Human hepatocytes, HepG2 and Hep3B cells, were cultured with human enterocytes Caco-2 cells to mimic gut-liver circulation to investigate the potential mechanism of NASH development.

Results: Significant increase of FGF15 production was found in the liver of the NASH-FGF21KO mice, however the increased FGF15 protein was unable to alleviate hepatic lipid accumulation. In contrast, up-regulated FGF15/19/FGFR4 signaling was found in the FGF21KO mice with increased NASH severity, as evident by hepatocyte injury/repair, fibrosis and potential malignant events. In in vitro studies, blockage of FGFR4 by BLU9931 treatment attenuated the lipid accumulation, up-regulated cyclin D1, and epithelial-mesenchymal transition (EMT) in the hepatocytes.

Conclusion: The increased FGF15 in NASH-FGF21KO mice could not substitute for FGF21 to compensate its lipid metabolic benefits thereby to prevent NASH development. Up-regulated FGFR4 signaling in NASH-FGF21KO mice coupled to proliferation and EMT events which were widely accepted to be associated with carcinogenic transformation.

The Role of Fibroblast Growth Factor 19 in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is the fifth most common type of cancer and the third leading cause of cancer-related deaths worldwide. Liver resection or liver transplantation is the most effective therapy for HCC because drugs approved by the US Food and Drug Administration to treat patients with unresectable HCC have an unfavorable overall survival rate. Therefore, the development of biomarkers for early diagnosis and effective therapy strategies are still necessary to improve patient outcomes. Fibroblast growth factor (FGF) 19 was amplified in patients with HCC from various studies, including patients from The Cancer Genome Atlas. FGF19 plays a syngeneic function with other signaling pathways in primary liver cancer development, such as epidermal growth factor receptor, Wnt/β-catenin, the endoplasmic reticulum-related signaling pathway, STAT3/IL-6, RAS, and extracellular signal-regulated protein kinase, among others. The current review presents a comprehensive description of the FGF19 signaling pathway involved in liver cancer development. The use of big data and bioinformatic analysis can provide useful clues for further studies of the FGF19 pathway in HCC, including its application as a biomarker, targeted therapy, and combination therapy strategies.

Fibroblast Growth Factor 19: Potential modulation of hepatic metabolism for the treatment of non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is a spectrum of liver disease that is becoming more prevalent in concert with obesity and poor lifestyle habits. Although NAFLD is treatable via lifestyle modification in early stages, more advanced liver pathologies (eg non-alcoholic steatohepatitis [NASH]) are harder to reverse. There is no Food and Drug Administration approved pharmacological treatment for NAFLD, and little research has been done to identify compounds that target key NAFLD mechanisms. Bile acids and bile acid receptors have been implicated in NAFLD pathogenesis and modulating bile acids and bile acid receptors has recently been targeted as a therapeutic treatment option for NAFLD. Fibroblast growth factor 19 (FGF19), a nutritionally regulated post-prandial hormone, is a chief regulator of bile acid metabolism and an important player in lipid and carbohydrate metabolism, including key mechanisms of NAFLD pathogenesis. In this review, we discuss recent findings related to FGF19-regulated processes involved in the pathogenesis of NAFLD. We summarize known and conjectural frameworks and limitations for the clinical application of FGF19-targeted therapies as they relate to NAFLD.

Novel Regulatory Factors and Small-Molecule Inhibitors of FGFR4 in Cancer

Fibroblast growth factor receptor 4 (FGFR4) is a tyrosine kinase receptor that is a member of the fibroblast growth factor receptor family and is stimulated by highly regulated ligand binding. Excessive expression of the receptor and its ligand, especially FGF19, occurs in many types of cancer. Abnormal FGFR4 production explains these cancer formations, and therefore, this receptor has emerged as a potential target for inhibiting cancer development. This review discusses the diverse mechanisms of oncogenic activation of FGFR4 and highlights some currently available inhibitors targeting FGFR4.

FGF19/FGFR4 signaling axis confines and switches the role of melatonin in head and neck cancer metastasis

BACKGROUND

There is no consensus about the effective dosages of melatonin in cancer management, thus, it is imperative to fully understand the dose-dependent responsiveness of cancer cells to melatonin and the underlying mechanisms.

METHODS

Head and neck squamous cell carcinoma (HNSCC) cells with or without melatonin treatment were used as a research platform. Gene depletion was achieved by short hairpin RNA, small interfering RNA, and CRISPR/Cas9. Molecular changes and regulations were assessed by Western blotting, quantitative RT-PCR (qRT-PCR), immunohistochemistry, and chromatin Immunoprecipitation coupled with qPCR (ChIP-qPCR). The therapeutic efficacy of FGF19/FGFR4 inhibition in melatonin-mediated tumor growth and metastasis was evaluated in orthotopic tongue tumor mice.

RESULTS

The effect of melatonin on controlling cell motility and metastasis varies in HNSCC cells, which is dose-dependent. Mechanistically, high-dose melatonin facilitates the upregulation of FGF19 expression through activating endoplasmic stress (ER)-associated protein kinase RNA-like endoplasmic reticulum kinase (PERK)-Eukaryotic initiation factor 2 alpha (eIF2α)-activating transcription factor 4 (ATF4) pathway, which in turn promotes FGFR4-Vimentin invasive signaling and attenuates the role of melatonin in repressing metastasis. Intriguingly, following long-term exposure to high-dose melatonin, epithelial HNSCC cells revert the process towards mesenchymal transition and turn more aggressive, which is enabled by FGF19/FGFR4 upregulation and alleviated by genetic depletion of the FGF19 and FGFR4 genes or the treatment of FGFR4 inhibitor H3B-6527.

CONCLUSIONS

Our study gains novel mechanistic insights into melatonin-mediated modulation of FGF19/FGFR4 signaling in HNSCC, demonstrating that activating this molecular node confines the role of melatonin in suppressing metastasis and even triggers the switch of its function from anti-metastasis to metastasis promotion. The blockade of FGF19/FGFR4 signaling would have great potential in improving the efficacy of melatonin supplements in cancer treatment.

FGF19/SOCE/NFATc2 signaling circuit facilitates the self-renewal of liver cancer stem cells

Background & Aims: Liver cancer stem cells (LCSCs) mediate therapeutic resistance and correlate with poor outcomes in patients with hepatocellular carcinoma (HCC). Fibroblast growth factor (FGF)-19 is a crucial oncogenic driver gene in HCC and correlates with poor prognosis. However, whether FGF19 signaling regulates the self-renewal of LCSCs is unknown.

Methods: LCSCs were enriched by serum-free suspension. Self-renewal of LCSCs were characterized by sphere formation assay, clonogenicity assay, sorafenib resistance assay and tumorigenic potential assays. Ca²⁺ image was employed to determine the intracellular concentration of Ca²⁺. Gain- and loss-of function studies were applied to explore the role of FGF19 signaling in the self-renewal of LCSCs.

Results: FGF19 was up-regulated in LCSCs, and positively correlated with certain self-renewal related genes in HCC. Silencing FGF19 suppressed self-renewal of LCSCs, whereas overexpressing FGF19 facilitated CSCs-like properties via activation of FGF receptor (FGFR)-4 in none-LCSCs. Mechanistically, FGF19/FGFR4 signaling stimulated store-operated Ca²⁺ entry (SOCE) through both the PLCγ and ERK1/2 pathways. Subsequently, SOCE-calcineurin signaling promoted the activation and translocation of nuclear factors of activated T cells (NFAT)-c2, which transcriptionally activated the expression of stemness-related genes (e.g., NANOG, OCT4 and SOX2), as well as FGF19. Furthermore, blockade of FGF19/FGFR4-NFATc2 signaling observably suppressed the self-renewal of LCSCs.

Conclusions: FGF19/FGFR4 axis promotes the self-renewal of LCSCs via activating SOCE/NFATc2 pathway; in turn, NFATc2 transcriptionally activates FGF19 expression. Targeting this signaling circuit represents a potential strategy for improving the therapeutic efficacy of HCC.

Enhanced expression of FGF19 predicts poor prognosis in patients with non-small cell lung cancer

Background

Lung cancer is one of the most common cancers and a leading cause of cancer-related death worldwide. Although many treatment options exist for lung cancer, some patients still suffer postoperative recurrence, and a consequent reduction of overall survival (OS). Our study aimed to investigate the correlation of FGF19 expression with the clinicopathological features and survival outcomes of non-small cell lung cancer (NSCLC) patients.

Methods

Bioinformatics analysis was conducted using the data from The Cancer Genome Atlas (TCGA) database to distinguish between the FGF19 levels of tumor and normal tissue and to determine their correlation with the OS. A total of 187 NSCLC patients who underwent radical resection of lung cancer were enrolled, and tissues were collected to determine FGF19 expression by immunohistochemistry (IHC) assay. Clinicopathological features including the survival date were collected for detailed research.

Results

According to the analysis based on the TCGA database, we found that the NSCLC tissues exhibited enhanced FGF19 messenger RNA (mRNA) expression and that the FGF19 mRNA levels correlated with shorter OS in NSCLC patients. IHC staining indicated that 88 (47.1%) patients had high FGF19 expression and 99 (52.9%) patients had low FGF19 expression. Meanwhile, survival data showed that high FGF19 expression was correlated with reduced OS (P<0.001). Moreover, both the univariate analysis and the forward stepwise multivariate Cox regression revealed that high FGF19 expression was an independent prognostic factor for decreased OS (P=0.001).

Conclusions

The expression of FGF19 is significantly upregulated in NSCLC, and the overexpression of FGF19 is correlated with poor OS, especially in lung adenocarcinoma (LUAD) cases. FGF19 might serve as a potential biomarker for predicting poor OS in NSCLC patients.

The Role of FGF19 and MALRD1 in Enterohepatic Bile Acid Signaling

Bile acids are the catabolic end products of cholesterol metabolism that are best known for their role in the digestion of lipids. In the last two decades, extensive investigation has shown bile acids to be important signaling molecules in metabolic processes throughout the body. Bile acids are ligands that can bind to several receptors, including the nuclear receptor farnesoid X receptor (FXR) in ileal enterocytes. FXR activation induces the expression of fibroblast growth factor (FGF) 15/19, a hormone that can modulate bile acid levels, repress gluconeogenesis and lipogenesis, and promote glycogen synthesis. Recent studies have described a novel intestinal protein, MAM and LDL Receptor Class A Domain containing 1 (MALRD1) that positively affects FGF15/19 levels. This signaling pathway presents an exciting target for treating metabolic disease and bile acid-related disorders.

Small hepatitis B virus surface antigen promotes malignant progression of hepatocellular carcinoma via endoplasmic reticulum stress-induced FGF19/JAK2/STAT3 signaling

Chronic hepatitis B virus (HBV) infection is one of the major global health problems. Although the small protein of hepatitis B virus surface antigen (HBsAg), SHBs, is the most abundant HBV viral protein, its pathogenic role and molecular mechanism in malignant progression of HBV-related hepatocellular carcinoma (HCC) remain largely unknown. Here we reported that SHBs expression induced epithelial-mesenchymal transition (EMT) process in HCC cells and significantly increased their migratory and invasive ability as well as metastatic potential. Mechanistically, SHBs expression in HCC cells induced endoplasmic reticulum (ER) stress that activated the activating transcription factor 4 (ATF4) to increase the expression and secretion of fibroblast growth factor 19 (FGF19). The autocrine released FGF19 in turn activated JAK2/STAT3 signaling for induction of EMT process in HCC. Notably, SHBs was positively correlated with the expression of mesenchymal markers, the phosphorylation status of JAK2 and STAT3 as well as FGF19 levels in human HCC samples. HCC patients with SHBs positive had a more advanced clinical stage and worse prognosis. These results suggest an important role of SHBs in the metastasis and progression of HCC and may highlight a potential target for preventive and therapeutic intervention of HBV-related HCC and its malignant progression.

Nuclear Factor Erythroid 2-Related Factor 2 in Regulating Cancer Metabolism

Significance: Nuclear factor erythroid 2 (NFE2)-related factor 2 (NFE2L2, or NRF2) is a transcription factor predominantly affecting the expression of antioxidant genes. NRF2 plays a significant role in the control of redox balance, which is crucial in cancer cells. NRF2 activation regulates numerous cancer hallmarks, including metabolism, cancer stem cell characteristics, tumor aggressiveness, invasion, and metastasis formation. We review the molecular characteristics of the NRF2 pathway and discuss its interactions with the cancer hallmarks previously listed. Recent Advances: The noncanonical activation of NRF2 was recently discovered, and members of this pathway are involved in carcinogenesis. Further, cancer-related changes (e.g., metabolic flexibility) that support cancer progression were found to be redox- and NRF2 dependent. Critical Issues: NRF2 undergoes Janus-faced behavior in cancers. The pro- or antineoplastic effects of NRF2 are context dependent and essentially based on the specific molecular characteristics of the cancer in question. Therefore, systematic investigation of NRF2 signaling is necessary to clarify its role in cancer etiology. The biggest challenge in the NRF2 field is to determine which cancers can be targeted for better clinical outcomes. Further, large-scale genomic and transcriptomic studies are missing to correlate the clinical outcome with the activity of the NRF2 system. Future Directions: To exploit NRF2 in a clinical setting in the future, the druggable members of the NRF2 pathway should be identified. In addition, it will be important to study how the modulation of the NRF2 system interferes with cytostatic drugs and their combinations.

FGF/FGFR signaling in health and disease

Growing evidences suggest that the fibroblast growth factor/FGF receptor (FGF/FGFR) signaling has crucial roles in a multitude of processes during embryonic development and adult homeostasis by regulating cellular lineage commitment, differentiation, proliferation, and apoptosis of various types of cells. In this review, we provide a comprehensive overview of the current understanding of FGF signaling and its roles in organ development, injury repair, and the pathophysiology of spectrum of diseases, which is a consequence of FGF signaling dysregulation, including cancers and chronic kidney disease (CKD). In this context, the agonists and antagonists for FGF-FGFRs might have therapeutic benefits in multiple systems.

CPI-613 rewires lipid metabolism to enhance pancreatic cancer apoptosis via the AMPK-ACC signaling

BACKGROUND

Pancreatic cancer remains one of the most rapidly progressive and deadly malignancies worldwide. Current treatment regimens only result in small improvements in overall survival for patients with this cancer type. CPI-613 (Devimistat), a novel lipoate analog inhibiting mitochondrial metabolism, shows the new hope for pancreatic cancer treatment as an efficient and well-tolerated therapeutic option treated alone or in combination with chemotherapy.

METHODS

Pancreatic cancer cells growing in planar 2D cultures and 3D scaffold were used as research platforms. Cell viability was measured by MTT and alamarBlue, and apoptosis was assessed by JC-1 staining and flow cytometry with Annexin V-FITC/PI staining. The mechanism behind CPI-613 action was analyzed by western blot, transmission electron microscopy, and lipolysis assay kits, in the presence or absence of additional signaling pathway inhibitors or gene modifications.

RESULTS

CPI-613 exhibits anticancer activity in pancreatic cancer cells by triggering ROS-associated apoptosis, which is accompanied by increased autophagy and repressed lipid metabolism through activating the AMPK signaling. Intriguingly, ACC, the key enzyme modulating lipid metabolism, is identified as a vital target of CPI-613, which is inactivated in an AMPK-dependent manner and influences apoptotic process upon CPI-613. Blockade or enhancement of autophagic process does not increase or blunt apoptosis to CPI-613, but inhibition of the AMPK-ACC signaling significantly attenuates apoptosis induced by CPI-613, suggesting CPI-613-mediated lipid metabolism reduction contributes to its cytotoxicity in pancreatic cancer cells.

CONCLUSIONS

These findings explore the critical role of lipid metabolism in apoptosis, providing new insights into the AMPK-ACC signaling axis in crosstalk between lipid metabolism and apoptosis in CPI-613 treatment.

TRAF6 Activates Fibroblasts to Cancer-Associated Fibroblasts through FGF19 in Tumor Microenvironment to Benefit the Malignant Phenotype of Melanoma Cells

Cancer-associated fibroblasts (CAFs) are an important component of the tumor microenvironment and mediate tumor progression in various cancers. A previous study demonstrated that TRAF6 promotes the malignant phenotype of melanoma cells. However, the role of TRAF6 in melanoma CAFs remains unclear. In this study, we found that TRAF6 was significantly upregulated in CAFs adjacent to melanoma cells. Functional assays showed that TRAF6 promoted fibroblast proliferation and migration as well as MMP and α-SMA expression. Moreover, the expression of TRAF6 in fibroblasts promoted the malignant phenotype of melanoma cells in vitro and in vivo. Meanwhile, the intervention of TRAF6 expression in melanoma cells affected the activation of CAFs. We found that FGF19 was a key cytokine regulated by TRAF6 through NF-κB1 using luciferase assay and chromatin immunoprecipitation in melanoma cells. Because plasma FGF19 levels are elevated in patients with melanoma, it may significantly induce fibroblast activation in vitro and in vivo. Taken together, our results support that TRAF6 is a key molecule that mediates the interaction between melanoma cells and stromal fibroblasts, suggesting that TRAF6 is a potentially promising target in melanoma therapy.

Enhanced autocrine FGF19/FGFR4 signaling drives the progression of lung squamous cell carcinoma, which responds to mTOR inhibitor AZD2104

Lung cancer occurrence and associated mortality ranks top in all countries. Despite the rapid development of targeted and immune therapies, many patients experience relapse within a few years. It is urgent to uncover the mechanisms that drive lung cancer progression and identify novel molecular targets. Our group has previously identified FGF19 as a prognostic marker and potential driver gene of lung squamous cell carcinomas (LSQ) in Chinese smoking patients. However, the underlying mechanism of how FGF19 promotes the progression of LSQ remains unclear. In this study, we characterized and confirmed that FGF19 serves as an oncogenic driver in LSQ development and progression, and reported that the amplification and high expression of FGF19 in LSQ was significantly associated with poor overall and progression-free survival. A higher serum level of FGF19 was found in lung cancer patients, which could also serve as a novel diagnostic index to screen lung cancer. Overproduction of FGF19 in LSQ cells markedly promoted cell growth, progression and metastasis, while downregulating FGF19 effectively inhibited LSQ progression in vitro and in vivo. Moreover, downregulating the receptor FGFR4 was also effective to suppress the growth and migration of LSQ cells. Since FGF19 could be induced by smoking or endoplasmic reticulum stress, to tackle the more malignant FGF19-overproducing LSQ, we reported for the first time that inhibiting mTOR pathway by using AZD2014 was effective and feasible. These findings have offered a new strategy by using anti-FGF19/FGFR4 therapy or mTOR-based therapy in FGF19-driven LSQ.

Dissecting the Role of the FGF19-FGFR4 Signaling Pathway in Cancer Development and Progression

Fibroblast growth factor (FGF) receptor 4 (FGFR4) belongs to a family of tyrosine kinase receptor. FGFR4 is highly activated in certain types of cancer and its activation is closely associated with its specific ligand, FGF19. Indeed, FGF19-FGFR4 signaling is implicated in many cellular processes including cell proliferation, migration, metabolism, and differentiation. Since active FGF19-FGFR4 signaling acts as an oncogenic pathway in certain types of cancer, the development and therapeutic evaluation of FGFR4-specific inhibitors in cancer patients is a topic of significant interest. In this review, we aim to provide an updated overview of currently-available FGFR4 inhibitors and their ongoing clinical trials, as well as upcoming potential therapeutics. Further, we examined the possibility of enhancing the therapeutic efficiency of FGFR4 inhibitors in cancer patients. We also discussed the underlying molecular mechanisms of oncogenic activation of FGFR4 by FGF19.

Serum Fibroblast Growth Factor 19 and Total Bile Acid Concentrations Are Potential Biomarkers of Hepatocellular Carcinoma in Patients with Type 2 Diabetes Mellitus

Purpose

Type 2 diabetes mellitus (T2DM) carries a high risk of hepatocellular carcinoma (HCC). Both serum fibroblast growth factor 19 (FGF19) and bile acid concentrations are associated with T2DM and HCC. We aimed at evaluating the relationships between FGF19 and bile acid concentrations and HCC in patients with T2DM.

Methods

Twenty-seven healthy volunteers (control group), 27 patients with T2DM (T2DM group), 16 patients with newly diagnosed HCC (HCC group), and 10 T2DM patients with newly diagnosed HCC (T2DM-HCC group) were studied at the Affiliated Hospital of Nantong University between June 2016 and June 2017. The serum concentrations of serum FGF19 and total bile acids (TBA) were measured in all the participants. Correlation analysis and multiple stepwise regression analysis of the FGF19 and TBA concentrations were performed in all the participants and in the four groups.

Results

The concentrations of FGF19 were 220.5 pg/ml, 185.1 pg/ml, 115.8 pg/ml, and 70.4 pg/ml in the HCC, T2DM-HCC, control, and T2DM groups, respectively (p < 0.001), and the TBA concentrations were 21.75 μmol/l, 14.25 μmol/l, 14.25 μmol/l, 14.25 μmol/l, 14.25 p < 0.001), and the TBA concentrations were 21.75 r = 0.777; p < 0.001), and the TBA concentrations were 21.75 r = 0.777; p < 0.001), and the TBA concentrations were 21.75 r = 0.777; p < 0.001), and the TBA concentrations were 21.75 r = 0.777; p < 0.001), and the TBA concentrations were 21.75 r = 0.777; p < 0.001), and the TBA concentrations were 21.75 

Conclusions

Simultaneous increase of serum FGF19 and TBA levels may be used as indicators of HCC screening at early stage in patients with T2DM.

Fibroblast growth factor signaling in non-alcoholic fatty liver disease and non-alcoholic steatohepatitis: Paving the way to hepatocellular carcinoma

Metabolic disorders are increasingly leading to non-alcoholic fatty liver disease, subsequent steatohepatitis, cirrhosis and hepatocellular carcinoma. Fibroblast growth factors and their receptors play an important role in maintaining metabolic homeostasis also in the liver and disorders in signaling have been identified to contribute to those pathophysiologic conditions leading to hepatic lipid accumulation and chronic inflammation. While specific and well tolerated inhibitors of fibroblast growth factor receptor activity are currently developed for (non-liver) cancer therapy, treatment of non-alcoholic fatty liver disease and non-alcoholic steatohepatitis is still limited. Fibroblast growth factor-mimicking or restoring approaches have recently evolved as a novel therapeutic option and the impact of such interactions with the fibroblast growth factor receptor signaling network during non-alcoholic fatty liver disease/non-alcoholic steatohepatitis development is reviewed here.

The microenvironmental and metabolic aspects of sorafenib resistance in hepatocellular carcinoma

In most cases, sorafenib-resistant HCC cells exhibit significant mesenchymal phenotype and stemness features. In this context, tumor cells might undergo cell fate transition in response to sorafenib or other targeted drugs in the presence or absence of genetic mutations. Therefore, understanding the major characteristics of drug-resistant cells state helps to discover new treatments that overcome drug resistance. To note, little is known about the metabolic or microenvironmental aspects of the certain tumor cell states beyond the genome. This review mainly focuses on the underlying mechanisms of acquired sorafenib resistance based on CSCs and EMT models, which explain tumor heterogeneity and have been considered the major cause of secondary sorafenib resistance. In particular, it discusses how the tumor microenvironment and tumor metabolism regulate cell stemness, mesenchymal state, and sorafenib resistance through epigenetic regulations, and provides reliable targets that might have synergetic effect with sorafenib.

FGF19 and FGF21 for the Treatment of NASH-Two Sides of the Same Coin? Differential and Overlapping Effects of FGF19 and FGF21 From Mice to Human

FGF19 and FGF21 analogues are currently in clinical development for the potential treatment of NASH. In Phase 2 clinical trials analogues of FGF19 and FGF21 decrease hepatic steatosis with up to 70% (MRI-PDFF) after 12 weeks and as early as 12-16 weeks of treatment an improvement in NASH resolution and fibrosis has been observed. Therefore, this class of compounds is currently of great interest in the field of NASH. FGF19 and FGF21 belong to the endocrine FGF19 subfamily and both require the co-receptor beta-klotho for binding and signalling through the FGF receptors. FGF19 is expressed in the ileal enterocytes and is released into the enterohepatic circulation in response to bile acids stimuli and in the liver FGF19 inhibits hepatic bile acids synthesis by transcriptional regulation of Cyp7A1, which is the rate limiting enzyme. FGF21 is, on the other hand, highly expressed in the liver and is released in response to high glucose, high free-fatty acids and low amino-acid supply and regulates energy, glucose and lipid homeostasis by actions in the CNS and in the adipose tissue. FGF19 and FGF21 are differentially expressed, have distinct target tissues and separate physiological functions. It is therefore of peculiar interest to understand why treatment with both FGF19 and FGF21 analogues have strong beneficial effects on NASH parameters in mice and human and whether the mode of action is overlapping This review will highlight the physiological and pharmacological effects of FGF19 and FGF21. The potential mode of action behind the anti-steatotic, anti-inflammatory and anti-fibrotic effects of FGF19 and FGF21 will be discussed. Finally, development of drugs is always a risk benefit analysis and the human relevance of adverse effects observed in pre-clinical species as well as findings in humans will be discussed. The aim is to provide a comprehensive overview of the current understanding of this drug class for the potential treatment of NASH.

Tauroursodeoxycholic acid mediates endoplasmic reticulum stress and autophagy in adrenocortical carcinoma cells

Adrenocortical carcinoma (ACC) is an invasive tumor that occurs in the endocrine system. Increasing evidence has shown that endoplasmic reticulum (ER) stress and autophagy play an important role in tumor formation. Tauroursodeoxycholic acid (TUDCA) is an ER chemical chaperone that can alleviate ER stress. In the present study, TUDCA promoted the proliferation, migration and invasion of ACC SW-13 and NCI-H295R cells. Reverse transcription-quantitative PCR and western blot analysis showed that the expression of glucose-regulated protein 78, a promoter of ER stress, was decreased. The expression levels of protein kinase R (PKR)-like ER kinase and activating transcription factor 6 were correspondingly decreased, and the downstream proteins, C/EBP homologous protein and JNK, were also decreased. The expression levels of the autophagy factor microtubule-associated protein light chain 3-II/I and the anti-apoptotic factor Bcl-2 increased following TUDCA treatment, while the expression of the pro-apoptotic factor Bax decreased. TUDCA alleviated ER stress in ACC SW-13 and NCI-H295R cells and induced autophagy, thereby inhibiting ACC cell apoptosis. ER stress- and autophagy-related signaling pathways are involved in the occurrence of ACC, which may provide potential therapeutic targets for ACC treatment.

Downregulation of microRNA-302b-3p relieves oxygen-glucose deprivation/re-oxygenation induced injury in murine hippocampal neurons through up-regulating Nrf2 signaling by targeting fibroblast growth factor 15/19

MicroRNAs have emerged as critical mediators of cerebral ischaemia/reperfusion injury. Recent studies have demonstrated that microRNA-302b-3p (miR-302b-3p) plays an important role in regulating apoptosis and oxidative stress in various cells. However, whether miR-302b-3p is involved in regulating cerebral ischaemia/reperfusion injury-induced neuronal apoptosis and oxidative stress remains unknown. In the present study, we explored the potential function and molecular mechanism of miR-302b-3p in oxygen-glucose deprivation/re-oxygenation (OGD/R)-induced neuronal injury, using an in vitro model of cerebral ischaemia/reperfusion injury. We found that miR-302b-3p expression was up-regulated by OGD/R treatment in neurons. The inhibition of miR-302b-3p improved cell viability, and reduced apoptosis and the production of reactive oxygen species, showing a protective effect against OGD/R-induced injury. Interestingly, miR-302b-3p was shown to target and modulate murine fibroblast growth factor 15 (FGF15). Moreover, our results showed that miR-302b-3p down-regulation contributed to the promotion of nuclear factor erythroid 2-related factor 2 (Nrf2)/antioxidant response element (ARE)-mediated antioxidant signaling associated with the inactivation of glycogen synthase kinase-3β. However, the knockdown of FGF15 significantly reversed the miR-302b-3p inhibition-mediated protective effect in OGD/R-treated neurons. Overall, these results demonstrated that miR-302b-3p inhibition confers a neuroprotective effect in OGD/R-treated neurons by up-regulating Nrf2/ARE antioxidant signaling via targeting FGF15, providing a novel target for neuroprotection in cerebral ischaemia/reperfusion injury.