First-in-Human Phase I Study of Fisogatinib (BLU-554) Validates Aberrant FGF19 Signaling as a Driver Event in Hepatocellular Carcinoma

FGFR4 inhibition augments paclitaxel-induced cell death in ovarian cancer

OBJECTIVES

Epithelial ovarian cancer (EOC) is the most lethal gynecological malignancy, which has a high mortality rate due to frequent tumor recurrence. The development of drug resistance against the first-line chemotherapeutic agent, such as paclitaxel/Taxol®, represents a critical reason. The mechanisms of paclitaxel resistance remain largely unknown, and druggable drivers which can be targeted to prevent or revert paclitaxel resistance also need to be identified.

METHODS

Phos-tag-based screens in cells treated with paclitaxel were used to identify key regulators involved in paclitaxel resistance, such as fibroblast growth factor receptor 4 (FGFR4). The functional role of FGFR4 in regulating paclitaxel resistance was further identified using apoptosis assays, which included the identification of apoptotic marker levels and activities. The involvement of FGFR4 downstream signaling pathways involved in paclitaxel resistance were identified through western blotting and quantitative PCR. Their roles in regulating paclitaxel resistance were also validated using apoptosis assays. Immunofluorescent staining was performed to identify the synergy of paclitaxel and FGFR4 inhibition.

RESULTS

Functional in vitro and in vivo studies demonstrate that FGFR4 depletion suppresses ovarian cancer cell proliferation, migration, and tumor growth. Importantly, FGFR4 silencing or specific inhibition can sensitize ovarian cancer cells to paclitaxel, whereas FGFR4 overexpression confers paclitaxel resistance. Mechanistically, FGFR4 regulates paclitaxel sensitivity in EOC cells through modulating the expression of the anti-apoptotic protein B-cell lymphoma-extra large (Bcl-xL) via MEK-ERK-RSK signaling pathway. The inhibition of Bcl-xL or MEK-ERK-RSK signaling can also enhance paclitaxel-stimulated cytotoxicity.

CONCLUSION

These findings indicate that targeting FGFR4 can be a promising novel strategy to overcome paclitaxel resistance and improve the outcomes of EOC patients.

Optimization of Aminoindazole derivatives as highly selective covalent inhibitors for wild-type and mutant FGFR4

The Fibroblast growth factor receptor 4 (FGFR4) has emerged as a potential oncogenic driver in hepatocellular carcinoma (HCC), primarily due to aberrations in the FGFR4-FGF19 signaling axis. Although the FGFR4-selective inhibitors have been reported, none have received approval. Further, the clinical acquired resistance caused by FGFR4 mutations has become an unmet clinical need for cancer therapy. In this study, we designed and synthesized a series of 3-amido-1H-indazole-based FGFR4 irreversible inhibitors, targeting both wild-type FGFR4 and the gatekeeper and molecular brake mutants. The representative compound, 48c, exhibited potent inhibitory activity against FGFR4WT kinase (IC50 = 2.9 nM) and picomolar activity against FGFR4WT, FGFR4V550L, and FGFR4V550M-driven Ba/F3 cell lines (IC50 < 0.1, 0.3, and 0.3 nM, respectively). 48c exhibited high selectivity across a panel of 66 kinases harboring a cysteine at the hinge region, highlighting its potential as a promising therapeutic candidate for overcoming resistance in FGFR4-associated tumors.

The evolving landscape of biomarkers for systemic therapy in advanced hepatocellular carcinoma

Hepatocellular carcinoma (HCC) remains one of the most prevalent and deadliest cancers. With the approval of multiple first- and second-line agents, especially the combination therapies based on immune checkpoint inhibitor (ICI) regimens, the landscape of systemic therapy for advanced HCC (aHCC) is more diverse than ever before. The efficacy of current systemic therapies shows great heterogeneity in patients with aHCC, thereby identifying biomarkers for response prediction and patient stratification has become an urgent need. The main biomarkers for systemic therapy in hepatocellular carcinoma are derived from peripheral blood, tissues, and imaging. Currently, the understanding of the clinical response to systemic therapy indicates unequivocally that a single biomarker cannot be used to identify patients who are likely to benefit from these treatments. In this review, we provide an integrated landscape of the recent development in molecular targeted therapies and ICIs-based therapies, especially focusing on the role of clinically applicable predictive biomarkers. Additionally, we further highlight the latest advancements in biomarker-driven therapies, including targeted treatments, adoptive cell therapies, and bispecific antibodies.

FGFR as a Predictive Marker for Targeted Therapy in Gastrointestinal Malignancies: A Systematic Review

BACKGROUND

Gastrointestinal (GI) cancers constitute approximately 25% of cancers worldwide. The fibroblast growth factor receptor (FGFR) family is a promising target for immunotherapy aiming  to enhance survival rates. FGFR alterations are associated with GI carcinomas. Their predictive value in different malignancies remains a focus area. While FGFR inhibitors have been approved for cholangiocarcinoma (CC) therapy, uncertainties remain regarding other GI cancers.

METHODS

A systematic review was conducted using the following databases: CINAHL, Embase, Medline, Cochrane Library, PubMed, and Web of Science. The search terms included "FGFR" and each of the GI malignancies. A total of 18 studies were included in this review.

RESULTS

The efficacy of FGFR-targeted therapy is evident. Strong evidence supports the use of FGFR inhibitors in CC, gastro-oesophageal cancer (GC/OC), and hepatocellular cancer, while there is limited evidence for pancreatic cancer (PC) and colorectal cancer (CRC). Alteration forms like FGFR2 fusion or rearrangement are associated with CC, while FGFR2 amplification and FGFR2b overexpression are associated with GC/OC. The administration of multi-kinase inhibitors without prior genomic testing, makes distinct study outcomes not solely attributable to the FGFR blockade.

CONCLUSION

FGFRs have a predictive value for GI cancers. Certain FGFR alterations are predictable for specific GI cancers. The most established FGFR-targeted therapy is for CC. It is essential to expand the FGFR research field for PC and CRC. Consistent molecular diagnostics in clinical trials are vital to comprehend the patient population with the highest efficacy.

Integrative Multi-Omics Approaches Reveal Selectivity Profiles and Molecular Mechanisms of FIIN-2, a Covalent FGFR Inhibitor

Fibroblast growth factor receptor (FGFR) inhibitors are emerged as an important class of targeted therapies in oncology, targeting key pathways associated with tumor growth, angiogenesis, and resistance to conventional treatments. FIIN-2, the first irreversible covalent pan-FGFR inhibitor, has shown promise in overcoming resistance due to gatekeeper mutations; however, its selectivity and molecular mechanisms in tumors remain poorly understood. In this study, an FIIN-2 chemical probe is designed and synthesized to identify both established and novel targets in hepatocellular carcinoma (HCC) via chemoproteomic profiling. An integrative multi-omics approach, including chemoproteomic, phosphoproteomic, transcriptomic, and proteomic analyses, is utilized to elucidate the full spectrum of target proteins, signaling pathways, and downstream effectors regulated by FIIN-2 in HCC. Notably, adenosine monophosphate-activated protein kinase α1 (AMPKα1) is identified as a novel target of FIIN-2, with Cys185 identified as its covalent binding site. These findings reveal that FIIN-2 can induce autophagy by directly binding to and activating AMPKα1, influencing its anti-tumor activity in HCC cells. Overall, this study greatly advances the understanding of FIIN-2's on- and off-target effects, offering a comprehensive view of its molecular mechanisms in cancer cells. The integrative multi-omics approach provides a valuable framework for the development and optimization of covalent kinase inhibitors.

HBV Remodels PP2A Complexes to Rewire Kinase Signaling in Hepatocellular Carcinoma

Hepatitis B virus (HBV) infections promote liver cancer initiation by inducing inflammation and cellular stress. Despite a primarily indirect effect on oncogenesis, HBV is associated with a recurrent genomic phenotype in hepatocellular carcinoma (HCC), suggesting that it impacts the biology of established HCC. Characterization of the interaction of HBV with host proteins and the mechanistic contributions of HBV to HCC initiation and maintenance could provide insights into HCC biology and uncover therapeutic vulnerabilities. In this study, we used affinity purification mass spectrometry to comprehensively map a network of 145 physical interactions between HBV and human proteins in HCC. A subset of the host factors targeted by HBV proteins were preferentially mutated in non-HBV-associated HCC, suggesting that their interaction with HBV influences HCC biology. HBV interacted with proteins involved in mRNA splicing, mitogenic signaling, and DNA repair, with the latter set interacting with the HBV oncoprotein X (HBx). HBx remodeled the PP2A phosphatase complex by excluding striatin regulatory subunits from the PP2A holoenzyme, and the HBx effects on PP2A caused Hippo kinase activation. In parallel, HBx activated mTOR complex 2, which can prevent YAP degradation. mTOR complex 2-mediated upregulation of YAP was observed in human HCC specimens and mouse HCC models and could be targeted with mTOR kinase inhibitors. Thus, HBV interaction with host proteins rewires HCC signaling rather than directly activating mitogenic pathways, providing an alternative paradigm for the cellular effects of a tumor-promoting virus. Significance: Integrative proteomic and genomic analysis of HBV/host interactions illuminated modifiers of hepatocellular carcinoma behavior and key signaling mechanisms in advanced disease, which suggested that HBV may have therapeutically actionable effects.

Design, synthesis, and biological evaluation of Ponatinib-based N-Phenylpyrimidine-2-amine derivatives as novel fibroblast growth factor receptor 4 (FGFR4) selective inhibitors

Fibroblast growth factor receptor 4 (FGFR4) has been proven to be a promising target for FGFR-driven HCC therapy. Great efforts have been devoted to the discovery of FGFR4 inhibitors. In this article, a new class of Ponatinib-based N-phenylpyridine-2-amine derivatives was designed and synthesized as covalent and irreversible FGFR4 selective inhibitors through a rational drug design strategy. The representative compound 10f displayed significant FGFR4 inhibition and reasonable selectivity. Meanwhile, compound 10f strongly suppressed the proliferation of FGFR4 dependent HCC cells both in vitro and in vivo by inhibiting the FGFR4 signaling pathway. Moreover, the irreversible binding to Cys552 in FGFR4 of compound 10f was also characterized by LC-MS/MS. These results provide evidence of 10f as a potential lead compound targeting FGFR4 for anti-HCC agent development.

Targeting FGFR4 Abrogates HNF1A-driven Metastasis in Pancreatic Ductal Adenocarcinoma

Purpose

We previously identified an oncogenic role for the transcription factor HNF1A in pancreatic ductal adenocarcinoma (PDAC). However, the role of HNF1A in the metastatic progression of PDAC remains unknown and targeting modalities for HNF1A -dependent phenotypes have yet to be identified.

Experimental Design

Transwell chambers were used to assess the effects of HNF1A and FGFR4 modulation on the migration and invasion of ATCC and patient-derived PDAC cells in vitro . An intrasplenic injection xenograft model was used to evaluate the impact of HNF1A knockdown and overexpression on metastatic tumor burden. Single-cell RNA sequencing, tissue microarray (TMA) data, and UMAP spatial profiling were used to identify FGFR4 as an HNF1A target gene upregulated in metastatic cells. RNAi and two FGFR4 inhibiting modalities (H3B-6527 and U3- 1784) were utilized to demonstrate the efficacy of FGFR4 inhibiting agents at reducing HNF1A- driven metastasis.

Results

Knockdown of HNF1A significantly decreases and HNF1A overexpression significantly increases PDAC cell migration and invasion. In vivo studies show that HNF1A knockdown significantly abrogates metastasis, while overexpression significantly promotes metastasis. Single-cell RNAseq shows that FGFR4 is upregulated in metastatic PDAC cells and staining for HNF1A and FGFR4 in a PDAC TMA reveals significant correlation between HNF1A and FGFR4 in PDAC patients. Further, knockdown and inhibition of FGFR4 significantly decreases HNF1A- mediated cell migration and invasion, and blocks HNF1A-driven metastasis in vivo .

Conclusions

These findings demonstrate that HNF1A drives PDAC metastasis via upregulation of FGFR4, and FGFR4 inhibition is a potential mechanism to target metastasis in PDAC patients.

Translational Relevance

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal malignancies, made even more devastating when metastases overwhelm major organs. The vast majority of PDAC patients either present with metastases or will relapse with recurrent metastatic PDAC after primary tumor resection. Unfortunately, toxic and largely ineffective chemotherapies are currently the only approved treatment options for these patients and therefore there exists a critical and unmet clinical need for targeted therapies against pro-metastatic pathways in PDAC. In the current study, we identify HNF1A as an oncogenic transcription factor that drives metastasis in PDAC, and it does so through upregulation of the receptor tyrosine kinase FGFR4. Importantly, FGFR4 is a targetable vulnerability and treatment with an FGFR4 blocking antibody reduces HNF1A-driven metastasis. These findings suggest that FGFR4 inhibitors could be an efficacious treatment for PDAC patients for the prevention or delay of metastatic tumor development.

Hepatocellular carcinoma: signaling pathways and therapeutic advances

Liver cancer represents a major global health concern, with projections indicating that the number of new cases could surpass 1 million annually by 2025. Hepatocellular carcinoma (HCC) constitutes around 90% of liver cancer cases and is primarily linked to factors incluidng aflatoxin, hepatitis B (HBV) and C (HCV), and metabolic disorders. There are no obvious symptoms in the early stage of HCC, which often leads to delays in diagnosis. Therefore, HCC patients usually present with tumors in advanced and incurable stages. Several signaling pathways are dis-regulated in HCC and cause uncontrolled cell propagation, metastasis, and recurrence of HCC. Beyond the frequently altered and therapeutically targeted receptor tyrosine kinase (RTK) pathways in HCC, pathways involved in cell differentiation, telomere regulation, epigenetic modification and stress response also provide therapeutic potential. Investigating the key signaling pathways and their inhibitors is pivotal for achieving therapeutic advancements in the management of HCC. At present, the primary therapeutic approaches for advanced HCC are tyrosine kinase inhibitors (TKI), immune checkpoint inhibitors (ICI), and combination regimens. New trials are investigating combination therapies involving ICIs and TKIs or anti-VEGF (endothelial growth factor) therapies, as well as combinations of two immunotherapy regimens. The outcomes of these trials are expected to revolutionize HCC management across all stages. Here, we provide here a comprehensive review of cellular signaling pathways, their therapeutic potential, evidence derived from late-stage clinical trials in HCC and discuss the concepts underlying earlier clinical trials, biomarker identification, and the development of more effective therapeutics for HCC.

Drug-Induced Liver Injury Associated With Emerging Cancer Therapies

Targeted therapies and immunotherapies have shown great promise as best-in-class treatments for several cancers with respect to efficacy and safety. While liver test abnormalities are rather common in patients treated with kinase inhibitors or immunotherapy, events of severe hepatotoxicity in these patients are rare in comparison with those associated with chemotherapeutics. The underlying mechanisms and risk factors for severe hepatotoxicity with novel oncology therapies are not well understood, complicating the drug-induced liver injury (DILI) risk assessment in the preclinical and clinical phases of drug development. The epidemiological and clinical characteristics, as well as mechanisms of liver toxicity, are described here to the current state of knowledge. Tools to study and assess the risk of DILI during drug development are concisely summarised, focusing on caveats thereof for novel oncology treatments. Emerging tools to optimise safety assessments and gather additional mechanistic insights into DILI are introduced. Particularly in oncology, where standard liver signals during drug development are tolerated to a marginally higher degree than in other indications due to the life-saving, life-extending and quality-of-life improvements for patients with severe or advanced cancers versus previous standard-of-care therapeutics, safety assessments must be tailored to the drug and indication. Trends in patient safety-centred drug development programmes and regulatory approval processes must continually be revisited and streamlined via obtaining an overall greater understanding of DILI and the tools available to assess mechanisms of injury, frequency, severity and prognosis.

FGF-based drug discovery: advances and challenges

The fibroblast growth factor (FGF) family comprises 15 paracrine-acting and 3 endocrine-acting polypeptides, which govern a multitude of processes in human development, metabolism and tissue homeostasis. Therapeutic endocrine FGFs have recently advanced in clinical trials, with FGF19 and FGF21-based therapies on the cusp of approval for the treatment of primary sclerosing cholangitis and metabolic syndrome-associated steatohepatitis, respectively. By contrast, while paracrine FGFs were once thought to be promising drug candidates for wound healing, burns, tissue repair and ischaemic ailments based on their potent mitogenic and angiogenic properties, repeated failures in clinical trials have led to the widespread perception that the development of paracrine FGF-based drugs is not feasible. However, the observation that paracrine FGFs can exert FGF hormone-like metabolic activities has restored interest in these FGFs. The recent structural elucidation of the FGF cell surface signalling machinery and the formulation of a new threshold model for FGF signalling specificity have paved the way for therapeutically harnessing paracrine FGFs for the treatment of a range of metabolic diseases.

Structure-activity relationship studies of Imidazo[1',2':1,6]pyrido[2,3-d]pyrimidine derivatives to develop selective FGFR inhibitors as anticancer agents for FGF19-overexpressed hepatocellular carcinoma

The aberrant activation of fibroblast growth factor (FGF) and FGF receptor (FGFR)-mediated signaling pathways are associated with cancer development, including hepatocellular carcinoma (HCC). A novel series of imidazo[1',2':1,6]pyrido[2,3-d]pyrimidine, containing an acrylamide covalent warhead, were synthesized as selective FGFR 1-4 inhibitors. Compound 7n was identified as the most potent inhibitor against FGFR1, 2, and 4, with IC50 values of 8/4 nM (FGFR1/2) and 3.8 nM (FGFR4), and the covalent docking analyses suggested that 7n form a covalent adduct with cysteine residue on the hinge or p-loop of FGFR. Compound 7n exhibited a favorable pharmacokinetic profile and significant in vivo antitumor efficacy in human liver cancer xenograft mouse models (xenograft, FGF/FGFR-dependent HCC cells).

Next-Generation Immunotherapy for Hepatocellular Carcinoma: Mechanisms of Resistance and Novel Treatment Approaches

Hepatocellular carcinoma (HCC) is a leading cause of cancer-related mortality worldwide, and, with only 15-20% of HCC patients being suitable for potentially curative treatments, the vast majority of patients with HCC ultimately require systemic therapy. For decades, the choice of effective systemic therapy for HCC remained sparse. In recent years, after the combination of atezolizumab and bevacizumab demonstrated superior overall survival over the first-line standard, sorafenib, there has been a major therapeutic paradigm shift to immunotherapy-based regimens for HCC. While representing a great leap forward for the treatment of this cancer, the reality is that less than one-third of patients achieve an objective response to immune checkpoint inhibitor-based therapy, so there remains a significant clinical need for further therapeutic optimization. In this review, we provide an overview of the current landscape of immunotherapy for unresectable HCC and delve into the tumor intrinsic and extrinsic mechanisms of resistance to established immunotherapies with a focus on novel therapeutic targets with strong translational potential. Following this, we spotlight emerging immunotherapy approaches and notable clinical trials aiming to optimize immunotherapy efficacy in HCC that include novel immune checkpoint inhibitors, tumor microenvironment modulators, targeted delivery systems, and locoregional interventions.

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.

From darkness to light: Targeting CAFs as a new potential strategy for cancer treatment

Cancer-associated fibroblasts (CAFs), which are the most frequent stromal cells in the tumor microenvironment (TME), play a key role in the metastasis of tumor cells. Generally speaking, CAFs in cooperation with tumor cells can secrete various cytokines, proteins, growth factors, and metabolites to promote angiogenesis, mediate immune escape of tumor cells, enhance endothelial-to-mesenchymal transition, stimulate extracellular matrix remodeling, and preserve tumor cell stemness. These activities of CAFs provide a favorable exogenous pathway for tumor progression and metastasis, and a microenvironment that allows rapid growth of tumor cells, which always lead to poor prognosis for patients. More importantly, it seems that targeting CAFs is also a potential precision therapeutic strategy in clinical practice. Hence, this review outlines the origin of CAFs, the relationship between CAFs and cancer metastasis, and targeting CAFs as a potential strategy for cancer patients, which could give some inspirations for cancer treatment in clinic.

Fibroblast growth factor receptor four inhibitor FGF401 improves the efficacy of trastuzumab in FGFR4-overexpressing breast cancer cells

Breast cancer is the most common cancer among women. Among them, human epidermal growth factor receptor-positive (HER2+) breast cancer is more malignant. Fortunately, many anti-HER2 drugs are currently used in clinical treatments to increase patient survival. However, some HER2+ patients (~15%) still develop drug resistance after receiving trastuzumab treatment, leading to treatment failure. Using CCLE and METABRIC database analyses, we found that fibroblast growth factor receptor 4 (FGFR4) mRNA was highly detected in tumors from HER2+ breast cancer patients (p < .001) and was associated with poorer survival in breast cancer patients. Through retrospective immunohistochemical staining analysis, we detected higher expression of FGFR4 protein in breast cancer tissues collected from patients who were resistant to trastuzumab therapy compared with breast cancer patients who responded to treatment. An FGFR4 inhibitor (FGF401) effectively inhibits tumor growth in trastuzumab-insensitive patient-derived xenograft (PDX) tumor-bearing mice. For molecular mechanism studies, we demonstrated that HER2/FGFR4 protein complexes were detected on the cell membrane of the tumor tissues in these trastuzumab-insensitive PDX tumor tissues. After trastuzumab treatment in these drug-resistant breast cancer cells, FGFR4 translocates and enters the nucleus. However, trastuzumab-induced nuclear translocation of FGFR4/HER2-intracellular domain protein complex in trastuzumab-resistant cancer cells is blocked by FGF401 treatment. We believe that FGFR4 overexpression and complex formation with HER2 can serve as molecular markers to assist clinicians in identifying trastuzumab-resistant tumors. Our results suggest that FGF401 combined with trastuzumab as adjuvant therapy for patients with trastuzumab-resistant breast cancer may be a potential new treatment strategy.

Discovery of novel FGFR4 inhibitors through a build-up fragment strategy

Hepatocellular carcinoma (HCC) is a leading cause of cancer-related death. FGFR4 has been implicated in HCC progression, making it a promising therapeutic target. We introduce an approach for identifying novel FGFR4 inhibitors by sequentially adding fragments to a common warhead unit. This strategy resulted in the discovery of a potent inhibitor, 4c, with an IC50 of 33 nM and high selectivity among members of the FGFR family. Although further optimisation is required, our approach demonstrated the potential for discovering potent FGFR4 inhibitors for HCC treatment, and provides a useful method for obtaining hit compounds from small fragments.

Resistance to Tyrosine Kinase Inhibitors in Hepatocellular Carcinoma (HCC): Clinical Implications and Potential Strategies to Overcome the Resistance

Hepatocellular carcinoma (HCC) is a leading cause of cancer-related deaths worldwide, and the development of effective treatment strategies remains a significant challenge in the management of advanced HCC patients. The emergence of tyrosine kinase inhibitors (TKIs) has been a significant advancement in the treatment of HCC, as these targeted therapies have shown promise in prolonging the survival of patients with advanced disease. Although immunotherapy is currently considered as the first line of treatment for advanced HCC patients, many such patients do not meet the clinical criteria to be eligible for immunotherapy, and in many parts of the world there is still lack of accessibility to immunotherapy. As such, TKIs still serve as the first line of treatment and play a major role in the treatment repertoire for advanced HCC patients. However, the development of resistance to these agents is a major obstacle that must be overcome. In this review, we explore the underlying mechanisms of resistance to TKIs in HCC, the clinical implications of this resistance, and the potential strategies to overcome or prevent the emergence of resistance.

A primer on the pleiotropic endocrine fibroblast growth factor FGF19/FGF15

Fibroblast Growth Factor 19 (FGF19) is a member of the Fibroblast Growth Factor (FGF) family, known for its role in various cellular processes including embryonic development and metabolic regulation. FGF19 functions as an endocrine factor, influencing energy balance, bile acid synthesis, glucose and lipid metabolism, as well as cell proliferation. FGF19 has a conserved structure typical of FGFs but exhibits unique features. Unlike most FGFs, which act locally, FGF19 travels through the bloodstream to distant targets including the liver. Its interaction with the β-Klotho (KLB) co-receptor and FGF Receptor 4 (FGFR4) in hepatocytes or FGFR1c in extrahepatic tissues initiates signaling cascades crucial for its biological functions. Although the mouse ortholog, FGF15, diverges significantly from human FGF19 in protein sequence and receptor binding, studies of FGF15-deficient mice have led to a better understanding of the proteins' role in bile acid regulation, metabolism, and embryonic development. Overexpression studies in transgenic mice have further revealed roles in not only ameliorating metabolic diseases but also in promoting hepatocyte proliferation and tumorigenesis. This review summarizes the gene and protein structure of FGF19/15, its expression patterns, phenotypes in mutant models, and implication in human diseases, providing insights into potential therapeutic strategies targeting the FGF19 signaling pathway.

Promise and challenges of traditional Chinese medicine, specifically Calculus bovis, in liver cancer treatment

Liver cancer, one of the most common malignancies worldwide, ranks sixth in incidence and third in mortality. Liver cancer treatment options are diverse, including surgical resection, liver transplantation, percutaneous ablation, transarterial chemoembolization, radiotherapy, chemotherapy, targeted therapy, immunotherapy, and traditional Chinese medicine (TCM). A multidisciplinary team (MDT) is essential to customize treatment plans based on tumor staging, liver function, and performance status (PS), ensuring individualized patient care. Treatment decisions require a MDT to tailor strategies based on tumor staging, liver function, and PS, ensuring personalized care. The approval of new first-line and second-line drugs and the establishment of standard treatments based on immune checkpoint inhibitors have significantly expanded treatment options for advanced liver cancer, improving overall prognosis. However, many patients do not respond effectively to these treatments and ultimately succumb to the disease. Modern oncology treatments, while extending patient survival, often come with severe side effects, resistance, and damage to the body, negatively impacting quality of life. Huang et al's study published at World Journal of Gastroenterology rigorously validates the anticancer properties of Calculus bovis, enhancing our understanding of TCM and contributing to new liver cancer treatment strategies. For over 5000 years, TCM has been used in East Asian countries like China to treat various diseases, including liver conditions. Analysis of real-world clinical data suggests that for patients with advanced-stage tumors lacking effective treatments, integrated TCM therapies could provide significant breakthroughs.

Small-molecule-based targeted therapy in liver cancer

Liver cancer is one of the most prevalent malignant tumors worldwide. According to the Barcelona Clinic Liver Cancer staging criteria, clinical guidelines provide tutorials to clinical management of liver cancer at their individual stages. However, most patients diagnosed with liver cancer are at advanced stage; therefore, many researchers conduct investigations on targeted therapy, aiming to improve the overall survival of these patients. To date, small-molecule-based targeted therapies are highly recommended (first line: sorafenib and lenvatinib; second line: regorafenib and cabozantinib) by current the clinical guidelines of the American Society of Clinical Oncology, European Society for Medical Oncology, and National Comprehensive Cancer Network. Herein, we summarize the small-molecule-based targeted therapies in liver cancer, including the approved and preclinical therapies as well as the therapies under clinical trials, and introduce their history of discovery, clinical trials, indications, and molecular mechanisms. For drug resistance, the revealed mechanisms of action and the combination therapies are also discussed. In fact, the known small-molecule-based therapies still have limited clinical benefits to liver cancer patients. Therefore, we analyze the current status and give our ideas for the urgent issues and future directions in this field, suggesting clues for novel techniques in liver cancer treatment.

Fibroblast growth factor receptor 4 deficiency in macrophages aggravates experimental colitis by promoting M1-polarization

OBJECTIVE AND DESIGN

Compelling evidence indicates that dysregulated macrophages may play a key role in driving inflammation in inflammatory bowel disease (IBD). Fibroblast growth factor (FGF)-19, which is secreted by ileal enterocytes in response to bile acids, has been found to be significantly lower in IBD patients compared to healthy individuals, and is negatively correlated with the severity of diarrhea. This study aims to explore the potential impact of FGF19 signaling on macrophage polarization and its involvement in the pathogenesis of IBD.

METHODS

The dextran sulfate sodium (DSS)-induced mouse colitis model was utilized to replicate the pathology of human IBD. Mice were created with a conditional knockout of FGFR4 (a specific receptor of FGF19) in myeloid cells, as well as mice that overexpressing FGF19 specifically in the liver. The severity of colitis was measured using the disease activity index (DAI) and histopathological staining. Various techniques such as Western Blotting, quantitative PCR, flow cytometry, and ELISA were employed to assess polarization and the expression of inflammatory genes.

RESULTS

Myeloid-specific FGFR4 deficiency exacerbated colitis in the DSS mouse model. Deletion or inhibition of FGFR4 in bone marrow-derived macrophages (BMDMs) skewed macrophages towards M1 polarization. Analysis of transcriptome sequencing data revealed that FGFR4 deletion in macrophages significantly increased the activity of the complement pathway, leading to an enhanced inflammatory response triggered by LPS. Mechanistically, FGFR4-knockout in macrophages promoted complement activation and inflammatory response by upregulating the nuclear factor-κB (NF-κB)-pentraxin3 (PTX3) pathway. Additionally, FGF19 suppressed these pathways and reduced inflammatory response by activating FGFR4 in inflammatory macrophages. Liver-specific overexpression of FGF19 also mitigated inflammatory responses induced by DSS in vivo.

CONCLUSION

Our study highlights the significance of FGF19-FGFR4 signaling in macrophage polarization and the pathogenesis of IBD, offering a potential new therapeutic target for IBD.

Recent developments in molecular targeted therapies for hepatocellular carcinoma in the genomic era

INTRODUCTION

Primary liver cancer is a major health problem being the sixth most frequent cancer in the world and the third cause of cancer-related death in the world. The most common histological type of liver cancer is hepatocellular carcinoma (HCC, 75-80%).

AREAS COVERED

Based on primary literature, this review provides an updated analysis of studies of genetic characterization of HCC at the level of gene mutation profiling, copy number alterations, and gene expression, with the definition of molecular subgroups and the identification of some molecular biomarkers and therapeutic targets. Recent therapeutic developments are also highlighted.

EXPERT OPINION

Deepening the understanding of the molecular complexity of HCC is progressively paving the way for the development of more personalized treatment approaches. Two important strategies involve the definition and validation of molecularly defined therapeutic targets in a subset of HCC patients and the identification of suitable biomarkers for approved systematic therapies (multikinase inhibitors and immunotherapies). The extensive molecular characterization of patients at the genomic and transcriptomic levels and the inclusion of detailed and relevant translational studies in clinical trials will represent a fundamental tool for improving the benefit of systemic therapies in HCC.

Targeted therapies in hepatocellular carcinoma: past, present, and future

Targeted therapies are the mainstay of systemic therapies for patients with advanced, unresectable, or metastatic hepatocellular carcinoma. Several therapeutic targets, such as c-Met, TGF-β, and FGFR, have been evaluated in the past, though results from these clinical studies failed to show clinical benefit. However, these remain important targets for the future with novel targeted agents and strategies. The Wnt/β-catenin signaling pathway, c-Myc oncogene, GPC3, PPT1 are exciting novel targets, among others, currently undergoing evaluation. Through this review, we aim to provide an overview of previously evaluated and potentially novel therapeutic targets and explore their continued relevance in ongoing and future studies for HCC.

Lenvatinib in hepatocellular carcinoma: Resistance mechanisms and strategies for improved efficacy

Hepatocellular carcinoma (HCC), one of the most prevalent and destructive causes of cancer-related deaths worldwide, approximately 70% of patients with HCC exhibit advanced disease at diagnosis, limiting the potential for radical treatment. For such patients, lenvatinib, a long-awaited alternative to sorafenib for first-line targeted therapy, has become a key treatment. Unfortunately, despite some progress, the prognosis for advanced HCC remains poor because of drug resistance development. However, the molecular mechanisms underlying lenvatinib resistance and ways to relief drug resistance in HCC are largely unknown and lack of systematic summary; thus, this review not only aims to explore factors contributing to lenvatinib resistance in HCC, but more importantly, summary potential methods to conquer or mitigate the resistance. The results suggest that abnormal activation of pathways, drug transport, epigenetics, tumour microenvironment, cancer stem cells, regulated cell death, epithelial-mesenchymal transition, and other mechanisms are involved in the development of lenvatinib resistance in HCC and subsequent HCC progression. To improve the therapeutic outcomes of lenvatinib, inhibiting acquired resistance, combined therapies, and nano-delivery carriers may be possible approaches.

Discovery of 2,6-Naphthyridine Analogues as Selective FGFR4 Inhibitors for Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is the most common type of liver cancer and is responsible for 90% of cases. Approximately 30% of patients diagnosed with HCC are identified as displaying an aberrant expression of fibroblast growth factor 19 (FGF19)-fibroblast growth factor receptor 4 (FGFR4) as an oncogenic-driver pathway. Therefore, the control of the FGF19-FGFR4 signaling pathway with selective FGFR4 inhibitors can be a promising therapy for the treatment of HCC. We herein disclose the design and synthesis of novel FGFR4 inhibitors containing a 2,6-naphthyridine scaffold. Compound 11 displayed a nanomolar potency against Huh7 cell lines and high selectivity over FGFR1-3 that were comparable to that of fisogatinib (8) as a reference standard. Additionally, compound 11 demonstrated remarkable antitumor efficacy in the Huh7 and Hep3B HCC xenograft mouse model. Moreover, bioluminescence imaging experiments with the orthotopic mouse model support that compound 11 can be considered a promising candidate for treating HCC.

Discovery of N-(4-((6-(3,5- Dimethoxyphenyl)-9H-purine derivatives as irreversible covalent FGFR inhibitors

Fibroblast growth factor receptor (FGFR) is an attractive target for cancer therapy, but existing FGFR inhibitors appear to hardly meet the demand for clinical application. Herein, a number of irreversible covalent FGFR inhibitors were designed and synthesized by selecting several five- and six-membered azaheterocycles as parent scaffold with different substituents to take over the hydrophobic region in the active pocket of FGFR proteins. Among the resulting target compounds, III-30 showed the most potent effect on enzyme activity inhibition and anti-proliferative activity against the tested cancer cell lines. Significantly, III-30 could inhibit the enzyme activity by achieving irreversible covalent binding with FGFR1 and FGFR4 proteins. It could also regulate FGFR-mediated signaling pathway and mitochondrial apoptotic pathway to promote cancer cell apoptosis and inhibit cancer cell invasion and metastasis. Moreover, III-30 had a good metabolic stability and showed relatively potent anti-tumor activity in the MDA-MB-231 xenograft tumor mice model.

Blocking of FGFR4 signaling by F30 inhibits hepatocellular carcinoma cell proliferation through HMOX1-dependent ferroptosis pathway

Excessive activation of FGF19/fibroblast growth factor receptor 4 (FGFR4) signaling is associated with poor survival of patients with hepatocellular carcinoma (HCC). FGFR4 inhibitors show promise for HCC treatment. F30, an indazole derivative designed through computer-aided drug design targeting FGFR4, demonstrated anti-HCC activity as described in our previous studies. However, the precise molecular mechanisms underlying F30's anticancer effects remain largely unexplored. We report here that F30 could effectively induce ferroptosis in HCC cells. The concentrations of cellular ferrous iron, the peroxidation of cell membranes and the homeostasis of reduced glutathione (GSH)/oxidized glutathione disulfide (GSSG) were dysregulated by F30, thereby affecting cellular redox status. Induction of ferroptosis in HCC by F30 was inhibited by specific ferroptosis inhibitor ferrostatin-1. F30 upregulates various ferroptosis-related genes, including the heme oxygenase enzymes 1 (HMOX1), a key mediator of redox regulation. Surprisingly, F30-induced ferroptosis in HCC is dependent on HMOX1. The dysregulation of cellular ferrous iron concentrations and cell membrane peroxidation was rescued when knocking down HMOX1 with specific small interfering RNA. These findings shed light on the molecular mechanisms underlying FGFR4-targeting F30's anti-HCC effects and suggest that FGFR4 inactivation could be beneficial for HCC treatment involving ferroptosis.

Therapeutic targeting of PLK1 in TERT promoter-mutant hepatocellular carcinoma

BACKGROUND

Hotspot mutations in the promoter of telomerase reverse transcriptase (TERT) gene are the most common genetic variants in hepatocellular carcinoma (HCC) and associated with poor prognosis of the disease. However, no drug was currently approved for treating TERT promoter mutation positive HCC patients. Here, we aim to explore the potential therapeutic strategy for targeting TERT promoter mutation in HCC.

METHODS

The Liver Cancer Model Repository database was used for screening potential drugs to selectively suppress the growth of TERT promoter mutant HCC cells. RNA-seq, CRISPR-Cas9 technology and siRNA transfection were performed for mechanistic studies. Cell counting kit-8 (CCK8) assay and the xenograft tumour models were used for cell growth detection in vitro and in vivo, respectively. Cell apoptosis and cell cycle arrest were analysed by Annexin V-FITC staining and/or propidium iodide staining.

RESULTS

PLK1 inhibitors were remarkably more sensitive to HCC cells harbouring TERT promoter mutation than wild-type cells in vitro and in vivo, which were diminished after TERT promoter mutation was edited to the wild-type nucleotide. Comparing the HCC cells with wild-type promoter of TERT, PLK1 inhibitors specifically downregulated Smad3 to regulate TERT for inducing apoptosis and G2/M arrest in TERT mutant HCC cells. Moreover, knockout of Smad3 counteracted the effects of PLK1 inhibitors in TERT mutant HCC cells. Finally, a cooperative effect of PLK1 and Smad3 inhibition was observed in TERT mutant cells.

CONCLUSIONS

PLK1 inhibition selectively suppressed the growth of TERT mutant HCC cells through Smad3, thus contributed to discover a novel therapeutic strategy to treat HCC patients harbouring TERT promoter mutations.

KEY POINTS

TERT promoter mutation confers sensitivity to PLK1 inhibitors in HCC. The selective growth inhibition of TERT mutant HCC cells induced by PLK1 inhibitor was mediated by Smad3. Combined inhibition of PLK1 and Smad3 showed a cooperative anti-tumor effect in TERT mutant HCC cells.

Development of Highly Potent and Selective Covalent FGFR4 Inhibitors Based on SNAr Electrophiles

Fibroblast growth factor receptor 4 (FGFR4) is thought to be a driver in several cancer types, most notably in hepatocellular carcinoma. One way to achieve high potency and isoform selectivity for FGFR4 is covalently targeting a rare cysteine (C552) in the hinge region of its kinase domain that is not present in other FGFR family members (FGFR1-3). Typically, this cysteine is addressed via classical acrylamide electrophiles. We demonstrate that noncanonical covalent "warheads" based on nucleophilic aromatic substitution (SNAr) chemistry can be employed in a rational manner to generate highly potent and (isoform-)selective FGFR4 inhibitors with a low intrinsic reactivity. Key compounds showed low to subnanomolar potency, efficient covalent inactivation kinetics, and excellent selectivity against the other FGFRs, the kinases with an equivalent cysteine, and a representative subset of the kinome. Moreover, these compounds achieved nanomolar potencies in cellular assays and demonstrated good microsomal stability, highlighting the potential of SNAr-based approaches in covalent inhibitor design.

FGFR-targeted therapeutics: clinical activity, mechanisms of resistance and new directions

Fibroblast growth factor (FGF) signalling via FGF receptors (FGFR1-4) orchestrates fetal development and contributes to tissue and whole-body homeostasis, but can also promote tumorigenesis. Various agents, including pan-FGFR inhibitors (erdafitinib and futibatinib), FGFR1/2/3 inhibitors (infigratinib and pemigatinib), as well as a range of more-specific agents, have been developed and several have entered clinical use. Erdafitinib is approved for patients with urothelial carcinoma harbouring FGFR2/3 alterations, and futibatinib and pemigatinib are approved for patients with cholangiocarcinoma harbouring FGFR2 fusions and/or rearrangements. Clinical benefit from these agents is in part limited by hyperphosphataemia owing to off-target inhibition of FGFR1 as well as the emergence of resistance mutations in FGFR genes, activation of bypass signalling pathways, concurrent TP53 alterations and possibly epithelial-mesenchymal transition-related isoform switching. The next generation of small-molecule inhibitors, such as lirafugratinib and LOXO-435, and the FGFR2-specific antibody bemarituzumab are expected to have a reduced risk of hyperphosphataemia and the ability to overcome certain resistance mutations. In this Review, we describe the development and current clinical role of FGFR inhibitors and provide perspective on future research directions including expansion of the therapeutic indications for use of FGFR inhibitors, combination of these agents with immune-checkpoint inhibitors and the application of novel technologies, such as artificial intelligence.

FGF19-Based Mini Probe Targeting FGFR4 for Diagnosis and Surgical Navigation of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is a frequent malignancy that has a high death rate and a high rate of recurrence following surgery, owing to insufficient surgical resection. Furthermore, HCC is prone to peritoneal metastasis (HCC-PM), resulting in a significant number of tiny cancer lesions, making surgical removal more challenging. As a potential imaging target, FGFR4 is highly expressed in tumors, especially in HCC, but is less expressed in the normal liver. In this study, we used computational simulation approaches to develop peptide I0 derived from FGF19, a particular ligand of FGFR4, and labeled it with the NIRF dye, MPA, for HCC detection. In surgical navigation, the TBR was 9.31 ± 1.36 and 8.57 ± 1.15 in HepG2 in situ tumor and HCC-PM models, respectively, indicating considerable tumor uptake. As a result, peptide I0 is an excellent clinical diagnostic reagent for HCC, as well as a tool for surgically resecting HCC peritoneal metastases.

Targeting the FGF19-FGFR4 pathway for cholestatic, metabolic, and cancerous diseases

Human fibroblast growth factor 19 (FGF19, or FGF15 in rodents) plays a central role in controlling bile acid (BA) synthesis through a negative feedback mechanism. This process involves a postprandial crosstalk between the BA-activated ileal farnesoid X receptor and the hepatic Klotho beta (KLB) coreceptor complexed with fibrobalst growth factor receptor 4 (FGFR4) kinase. Additionally, FGF19 regulates glucose, lipid, and energy metabolism by coordinating responses from functional KLB and FGFR1-3 receptor complexes on the periphery. Pharmacologically, native FGF19 or its analogs decrease elevated BA levels, fat content, and collateral tissue damage. This makes them effective in treating both cholestatic diseases such as primary biliary or sclerosing cholangitis (PBC or PSC) and metabolic abnormalities such as nonalcoholic steatohepatitis (NASH). However, chronic administration of FGF19 drives oncogenesis in mice by activating the FGFR4-dependent mitogenic or hepatic regenerative pathway, which could be a concern in humans. Agents that block FGF19 or FGFR4 signaling have shown great potency in preventing FGF19-responsive hepatocellular carcinoma (HCC) development in animal models. Recent phase 1/2 clinical trials have demonstrated promising results for several FGF19-based agents in selectively treating patients with PBC, PSC, NASH, or HCC. This review aims to provide an update on the clinical development of both analogs and antagonists targeting the FGF19-FGFR4 signaling pathway for patients with cholestatic, metabolic, and cancer diseases. We will also analyze potential safety and mechanistic concerns that should guide future research and advanced trials.

Discovery of 6-Formylpyridyl Urea Derivatives as Potent Reversible-Covalent Fibroblast Growth Factor Receptor 4 Inhibitors with Improved Anti-Hepatocellular Carcinoma Activity

Fibroblast growth factor receptor 4 (FGFR4) has been considered as a potential anticancer target due to FGF19/FGFR4 mediated aberrant signaling in hepatocellular carcinoma (HCC). Several FGFR4 inhibitors have been reported, but none have gained approval. Herein, a series of 5-formyl-pyrrolo[3,2-b]pyridine-3-carboxamides and a series of 6-formylpyridyl ureas were characterized as selective reversible-covalent FGFR4 inhibitors. The representative 6-formylpyridyl urea 8z exhibited excellent potency against FGFR4WT, FGFR4V550L, and FGFR4V550M with IC50 values of 16.3, 12.6, and 57.3 nM, respectively. It also potently suppressed proliferation of Ba/F3 cells driven by FGFR4WT, FGFR4V550L, and FGFR4V550M, and FGFR4-dependent Hep3B and Huh7 HCC cells, with IC50 values of 1.2, 13.5, 64.5, 15.0, and 20.4 nM, respectively. Furthermore, 8z displayed desirable microsomal stability and significant in vivo efficacy in the Huh7 HCC cancer xenograft model in nude mice. The study provides a promising new lead for anticancer drug discovery directed toward overcoming FGFR4 gatekeeper mutation mediated resistance in HCC patients.

Precision treatment in advanced hepatocellular carcinoma

The past decade has witnessed significant advances in the systemic treatment of advanced hepatocellular carcinoma (HCC). Nevertheless, the newly developed treatment strategies have not achieved universal success and HCC patients frequently exhibit therapeutic resistance to these therapies. Precision treatment represents a paradigm shift in cancer treatment in recent years. This approach utilizes the unique molecular characteristics of individual patient to personalize treatment modalities, aiming to maximize therapeutic efficacy while minimizing side effects. Although precision treatment has shown significant success in multiple cancer types, its application in HCC remains in its infancy. In this review, we discuss key aspects of precision treatment in HCC, including therapeutic biomarkers, molecular classifications, and the heterogeneity of the tumor microenvironment. We also propose future directions, ranging from revolutionizing current treatment methodologies to personalizing therapy through functional assays, which will accelerate the next phase of advancements in this area.

Emerging therapies targeting growth factors in hepatocellular carcinoma

INTRODUCTION

Hepatocellular carcinoma (HCC) is a primary liver cancer that commonly arises in the background of chronic liver inflammation and/or cirrhosis. Chronic liver inflammation results in the production of different growth factors, remodeling of the microenvironment architecture into fibrosis, and eventually carcinogenesis. Overexpression of some growth factors has been associated with worse prognosis in patients with HCC. Targeted therapies against growth factors may disrupt cell signaling and the mechanisms that allow for cell survival (e.g. angiogenesis, proliferation, metastases).

AREAS COVERED

We herein review potential growth factor targets of HCC and the limited research that exists regarding targeted therapy of these ligands and their receptors. We performed an extensive literature search to investigate preclinical studies, clinical research, and clinical trials.

EXPERT OPINION

Systemic therapy for patients with HCC is continuing to evolve. Anti-angiogenic therapy holds the most promise among targeted therapy for growth factors among patients with HCC. Improving our understanding of growth factors in HCC will hopefully lead to the development of new targeted therapies and strategies for combination therapies with immune checkpoint inhibitors.

Pharmacological modulation of cholesterol 7α-hydroxylase (CYP7A1) as a therapeutic strategy for hypercholesterolemia

Despite the availability of many therapeutic options, the prevalence of hypercholesterolemia remains high. There exists a significant unmet medical need for novel drugs and/or treatment combinations to effectively combat hypercholesterolemia while minimizing adverse reactions. The modulation of cholesterol 7α-hydroxylase (CYP7A1) expression via perturbation of the farnesoid X receptor (FXR) - dependent pathways, primarily FXR/small heterodimer partner (SHP) and FXR/ fibroblast growth factor (FGF)-19/ fibroblast growth factor receptor (FGFR)-4 pathways, presents as a potential option to lower cholesterol levels. This paper provides a comprehensive review of the important role that CYP7A1 plays in cholesterol homeostasis and how its expression can be exploited to assert differential control of bile acid synthesis and cholesterol metabolism. Additionally, the paper also summarizes the current therapeutic options for hypercholesterolemia, and positions modulators of CYP7A1 expression, namely FGFR4 inhibitors and FXR antagonists, as emerging and distinct pharmacological agents to complement and diversify the treatment regime. Their mechanistic and clinical considerations are also extensively described to interrogate the benefits and risks associated with using FXR-mediating agents, either singularly or in combination with recognised agents such as statins to target hypercholesterolemia.

ORAOV1, CCND1, and MIR548K Are the Driver Oncogenes of the 11q13 Amplicon in Squamous Cell Carcinoma

11q13 amplification is a frequent event in human cancer and in particular in squamous cell carcinomas (SCC). Despite almost invariably spanning 10 genes, it is unclear which genetic components of the amplicon are the key driver events in SCC. A combination of computational, in vitro, ex vivo, and in vivo models leveraging efficient primary human keratinocyte genome editing by Cas9-RNP electroporation, identified ORAOV1, CCND1, and MIR548K as the critical drivers of the amplicon in head and neck SCC. CCND1 amplification drives the cell cycle in a CDK4/6/RB1-independent fashion and may confer a novel dependency on RRM2. MIR548K contributes to epithelial-mesenchymal transition. Finally, we identify ORAOV1 as an oncogene that acts likely via its ability to modulate reactive oxygen species. Thus, the 11q13 amplicon drives SCC through at least three independent genetic elements and suggests therapeutic targets for this morbid and lethal disease.

IMPLICATIONS

This work demonstrates novel mechanisms and ways to target these mechanisms underlying the most common amplification in squamous cell carcinoma, one of the most prevalent and deadly forms of human cancer.

FGF19 and its analog Aldafermin cooperate with MYC to induce aggressive hepatocarcinogenesis

FGF19 hormone has pleiotropic metabolic functions, including the modulation of insulin sensitivity, glucose/lipid metabolism and energy homeostasis. On top of its physiological metabolic role, FGF19 has been identified as a potentially targetable oncogenic driver, notably in hepatocellular carcinoma (HCC). Nevertheless, FGF19 remained an attractive candidate for treatment of metabolic disease, prompting the development of analogs uncoupling its metabolic and tumor-promoting activities. Using pre-clinical mice models of somatic mutation driven HCC, we assessed the oncogenicity of FGF19 in combination with frequent HCC tumorigenic alterations: p53 inactivation, CTNNB1 mutation, CCND1 or MYC overexpression. Our data revealed a strong oncogenic cooperation between FGF19 and MYC. Most importantly, we show that this oncogenic synergy is conserved with a FGF19-analog Aldafermin (NGM282), designed to solely mimic the hormone's metabolic functions. In particular, even a short systemic treatment with recombinant proteins triggered rapid appearance of proliferative foci of MYC-expressing hepatocytes. The fact that FGF19 analog Aldafermin is not fully devoid of the hormone's oncogenic properties raises concerns in the context of its potential use for patients with damaged, mutation-prone liver.

Activity of Tepotinib in Hepatocellular Carcinoma With High-Level MET Amplification: Preclinical and Clinical Evidence

PURPOSE

MET amplification (METamp) has been reported in 1%-5% of patients with hepatocellular carcinoma (HCC) and may be sensitive to MET inhibition. Tepotinib, a selective MET inhibitor, has shown promising activity in HCC with MET overexpression. We investigated the preclinical and clinical activity of tepotinib in HCC with METamp (MET gene copy number [GCN] ≥5), including high-level METamp (MET GCN ≥10).

METHODS

Preclinical antitumor activity of tepotinib 100 mg/kg (orally, days 1-5, every 7 days, 3-5 weeks; 3-12 replicates) was evaluated according to METamp status, as determined using the nCounter platform (NanoString), in 37 HCC patient-derived xenografts (PDXs) in immunodeficient mice. Clinical outcomes were evaluated in patients with METamp by fluorescence in situ hybridization who received tepotinib 500 mg (450 mg active moiety) in two phase Ib/II trials in HCC with MET overexpression.

RESULTS

Across the PDX models, tepotinib induced complete or near-complete tumor regression in the only two models with high-level METamp. Median tumor volume reductions were 100% and 99.8% in models with MET GCN 47.1 and 44.0, respectively. Across the two clinical trials, 15/121 patients had METamp. Disease control was achieved by 11/15 patients with METamp (complete response [CR], n = 1; partial response [PR], n = 4; stable disease [SD], n = 6) and 4/4 with high-level METamp (CR, n = 1; PR, n = 2; SD, n = 1). All three patients with high-level METamp and objective response received treatment for >1 year, including one patient who received first-line tepotinib for >6 years.

CONCLUSION

High-level METamp may be an oncogenic driver in HCC that is sensitive to MET inhibitors such as tepotinib.

Recent Progress in Systemic Therapy for Advanced Hepatocellular Carcinoma

Patients with advanced hepatocellular carcinoma (HCC) have several systemic treatment options. There are many known risk factors for HCC, and although some, such as hepatitis C, are now treatable, others are not. For example, metabolic dysfunction-related chronic liver disease is increasing in incidence and has no specific treatment. Underlying liver disease, drug resistance, and an increasing number of treatment options without specific biomarkers are all challenges in selecting the best treatment for each patient. Conventional chemotherapy is almost never used for advanced-stage disease, which instead is treated with immunotherapy, tyrosine kinase inhibitors, and VEGF inhibitors. Immune checkpoint inhibitors targeting various receptors have been or are currently undergoing clinical evaluation. Ongoing trials with three-drug regimens may be the future of advanced-stage HCC treatment. Other immune-modulatory approaches of chimeric antigen receptor-modified T cells, bispecific antibodies, cytokine-induced killer cells, natural killer cells, and vaccines are in early-stage clinical trials. Targeted therapies remain limited for HCC but represent an area of potential growth. As we shift away from first-line sorafenib for advanced HCC, clinical trial control arms should comprise a standard treatment other than sorafenib, one that is a better comparator for advancing therapies.

Molecular Targeting of the Fibroblast Growth Factor Receptor Pathway across Various Cancers

Fibroblast growth factor receptors (FGFRs) are a family of receptor tyrosine kinases that are involved in the regulation of cell proliferation, survival, and development. FGFR alterations including amplifications, fusions, rearrangements, and mutations can result in the downstream activation of tyrosine kinases, leading to tumor development. Targeting these FGFR alterations has shown to be effective in treating cholangiocarcinoma, urothelial carcinoma, and myeloid/lymphoid neoplasms, and there are currently four FGFR inhibitors approved by the Food and Drug Administration (FDA). There have been developments in multiple agents targeting the FGFR pathway, including selective FGFR inhibitors, ligand traps, monoclonal antibodies, and antibody-drug conjugates. However, most of these agents have variable and low responses, with some intolerable toxicities and acquired resistances. This review will summarize previous clinical experiences and current developments in agents targeting the FGFR pathway, and will also discuss future directions for FGFR-targeting agents.

Insight into the design of FGFR4 selective inhibitors in cancer therapy: Prospects and challenges

Recently, FGFR4 has become a hot target for the treatment of cancer owing to its important role in cellular physiological processes. FGFR4 has been validated to be closely related to the occurrence of cancers, such as hepatocellular carcinoma, rhabdomyosarcoma, breast cancer and colorectal cancer. Hence, the development of FGFR4 small-molecule inhibitors is essential to further understanding the functions of FGFR4 in cancer and the treatment of FGFR4-dependent diseases. Given the particular structures of FGFR1-4, the development of FGFR4 selective inhibitors presents significant challenges. The non-conserved Cys552 in the hinge region of the FGFR4 complex becomes the key to the selectivity of FGFR4 and FGFR1/2/3 inhibitors. In this review, we systematically introduce the close relationship between FGFR4 and cancer, and conduct an in-depth analysis of the developing methodology, binding mechanism, kinase selectivity, pharmacokinetic characteristics of FGFR4 selectivity inhibitors, and their application in clinical research.

Predictability of human exposure by human-CYP3A4-transgenic mouse models: A meta-analysis

First-in-human dose predictions are primarily based on no-observed-adverse-effect levels in animal studies. Predictions from these animal models are only as effective as their ability to predict human results. To narrow the gap between human and animals, researchers have, among other things, focused on the replacement of animal cytochrome P450 (CYP) enzymes with their human counterparts (called humanization), especially in mice. Whereas research in humanized mice is extensive, the emphasis has been particularly on qualitative rather than quantitative predictions. Because the CYP3A4 enzyme is most involved in the metabolism of clinically used drugs, most benefit was expected from CYP3A4 models. There are several applications of these mouse models regarding in vivo CYP3A4 functionality, one of which might be their capacity to help improve first-in-human (FIH) dose predictions for CYP3A4-metabolized drugs. To evaluate whether human-CYP3A4-transgenic mouse models are better predictors of human exposure compared to the wild-type mouse model, we performed a meta-analysis comparing both mouse models in their ability to accurately predict human exposure of small-molecule drugs metabolized by CYP3A4. Results showed that, in general, the human-CYP3A4-transgenic mouse model had similar accuracy in the prediction of human exposure compared to the wild-type mouse model, suggesting that there is limited added value in humanization of the mouse Cyp3a enzymes if the primary aim is to acquire more accurate FIH dose predictions. Despite the results of this meta-analysis, corrections for interspecies differences through extension of human-CYP3A4-transgenic mouse models with pharmacokinetic modeling approaches seems a promising contribution to more accurate quantitative predictions of human pharmacokinetics.

EGFR Inhibition Overcomes Resistance to FGFR4 Inhibition and Potentiates FGFR4 Inhibitor Therapy in Hepatocellular Carcinoma

Aberrant activation of the FGF19-FGFR4 signaling pathway plays an essential role in the tumorigenesis of hepatocellular carcinoma (HCC). As such, FGFR4 inhibition has emerged as a novel therapeutic option for the treatment of HCC and has shown preliminary efficacy in recent clinical trials for patients exhibiting aberrant FGF19 expression. Resistance to kinase inhibitors is common in oncology, presenting a major challenge in the clinical treatment process. Hence, we investigated the potential mechanisms mediating and causing resistance to FGFR4 inhibition in HCC. Upon the successful establishment of a battery of cellular models developing resistance to FGFR4 inhibitors, we have identified the activation of EGFR, MAPK, and AKT signaling as the primary mechanisms mediating the acquired resistance. Combination of inhibitors against EGFR or its downstream components restored sensitivity to FGFR4 inhibitors. In parental HCC cell lines, EGF treatment also resulted in resistance to FGFR4 inhibitors. This resistance was effectively reverted by inhibitors of the EGFR signaling pathway, suggesting that EGFR activation is a potential cause of intrinsic resistance. We further confirmed the above findings in vivo in mouse xenograft tumor models. Genomic analysis of patient samples from The Cancer Genome Atlas confirmed that a segment of patients with HCC harboring FGF19 overexpression indeed exhibited increased activation of EGFR signaling. These findings conclusively indicate that both induced and innate activation of EGFR could mediate resistance to FGFR4 inhibition, suggesting that dual blockade of EGFR and FGFR4 may be a promising future therapeutic strategy for the treatment of FGF19-FGFR4 altered HCC.

Molecular-based targeted therapies in patients with hepatocellular carcinoma and hepato-cholangiocarcinoma refractory to atezolizumab/bevacizumab

BACKGROUND & AIMS

The "French Medicine Genomic program 2025" has been designed to give patients with cancers that are refractory to systemic treatments access to off-label therapies adapted to their specific genomic profile. Herein, we reported the results of this program in patients with advanced hepatocellular carcinoma (HCC) and hepato-cholangiocarcinoma (H-CCK).

METHODS

In one center, all patients with HCC or H-CCK who progressed under atezolizumab/bevacizumab with available tumor frozen samples benefited from whole-genome/-exome and RNA sequencing. Targeted therapies were matched to genomic alterations following the recommendations of a molecular tumor board and radiological response and overall survival were assessed.

RESULTS

Among 135 patients with HCC and H-CCK treated by atezolizumab/bevacizumab, 20 patients benefited from genomic analysis after progression (16 HCC; 4 H-CCK). Nineteen patients had analyzable data, 70% were male, median age was 57 years, 65% had metastatic disease and 45% had vascular invasion. Among these 19 patients, 14 patients (76%) harbored at least one actionable genomic alteration and 9/14 received an adapted targeted therapy (45%). One patient with H-CCK showing CDK4 amplification was treated with palbociclib and achieved a partial radiological response for 16 months. Another patient with H-CCK, high HER2 overexpression and a high homologous recombination score was treated with trastuzumab/olaparib and had stable disease. One patient with an HCC and bi-allelic inactivation of TSC2 achieved a complete radiological response under everolimus. The remaining six treated patients (all HCC) had progressive disease, including three patients treated with trametinib, two with everolimus and one with olaparib.

CONCLUSION

Molecular-based guided therapy is feasible in patients with HCC/H-CCK progressing under atezolizumab/bevacizumab and may be useful in a small subset of patients.

IMPACT AND IMPLICATIONS

The use of whole-genome/-exome and RNA sequencing in clinical practice has not been reported in patients with hepatocellular carcinoma and hepato-cholangiocarcinoma. Herein, we performed a pilot study which suggested that whole-genome/-exome and RNA sequencing is feasible on tumor biopsies from patients refractory to atezolizumab/bevacizumab, with a small subset of patients exhibiting at least one actionable genomic alteration and receiving an adapted targeted therapy. This proof-of-concept study suggests that this clinical strategy could benefit a small subset of patients. Finally, validation of this approach will be required in a larger cohort of patients.

Tumor Microenvironment Composition and Related Therapy in Hepatocellular Carcinoma

Globally, primary liver cancer is the third leading cause of cancer death, and hepatocellular carcinoma (HCC) accounts for 75%-95%. The tumor microenvironment (TME), composed of the extracellular matrix, helper cells, immune cells, cytokines, chemokines, and growth factors, promotes the immune escape, invasion, and metastasis of HCC. Tumor metastasis and postoperative recurrence are the main threats to the long-term prognosis of HCC. TME-related therapies are increasingly recognized as effective treatments. Molecular-targeted therapy, immunotherapy, and their combined therapy are the main approaches. Immunotherapy, represented by immune checkpoint inhibitors (ICIs), and targeted therapy, highlighted by tyrosine kinase inhibitors (TKIs), have greatly improved the prognosis of HCC. This review focuses on the TME compositions and emerging therapeutic approaches to TME in HCC.

Design, synthesis, and biological evaluation of 1,6-naphthyridine-2-one derivatives as novel FGFR4 inhibitors for the treatment of colorectal cancer

Aberrant FGFR4 signaling has been implicated in the development of several cancers, making FGFR4 a promising target for cancer therapy. Several FGFR4-selective inhibitors have been developed, yet none of them have been approved. Herein, we report a novel series of 1,6-naphthyridine-2-one derivatives as potent and selective inhibitors targeting FGFR4 kinase. Preliminary structure-activity relationship analysis was conducted. The screening cascades revealed that 19g was the preferred compound among the prepared series. 19g demonstrated excellent kinase selectivity and substantial cytotoxic effect against all tested colorectal cancer cell lines. 19g induced significant tumor inhibition in a HCT116 xenograft mouse model without any apparent toxicity. Notably, 19g exhibited excellent potency in disrupting the phosphorylation of FGFR4 and downstream signaling proteins mediated by FGF18 and FGF19. Compound 19g might be a potential antitumor drug candidate for the treatment of colorectal cancer.

Futibatinib, an Irreversible FGFR1-4 Inhibitor for the Treatment of FGFR-Aberrant Tumors

Fibroblast growth factor receptors (FGFR) are emerging as an important therapeutic target for patients with advanced, refractory cancers. Most selective FGFR inhibitors under investigation show reversible binding, and their activity is limited by acquired drug resistance. This review summarizes the preclinical and clinical development of futibatinib, an irreversible FGFR1-4 inhibitor. Futibatinib stands out among FGFR inhibitors because of its covalent binding mechanism and low susceptibility to acquired resistance. Preclinical data indicated robust activity of futibatinib against acquired resistance mutations in the FGFR kinase domain. In early-phase studies, futibatinib showed activity in cholangiocarcinoma, and gastric, urothelial, breast, central nervous system, and head and neck cancers harboring various FGFR aberrations. Exploratory analyses indicated clinical benefit with futibatinib after prior FGFR inhibitor use. In a pivotal phase II trial, futibatinib demonstrated durable objective responses (42% objective response rate) and tolerability in previously treated patients with advanced intrahepatic cholangiocarcinoma harboring FGFR2 fusions or rearrangements. A manageable safety profile was observed across studies, and patient quality of life was maintained with futibatinib treatment in patients with cholangiocarcinoma. Hyperphosphatemia, the most common adverse event with futibatinib, was well managed and did not lead to treatment discontinuation. These data show clinically meaningful benefit with futibatinib in FGFR2-rearrangement-positive cholangiocarcinoma and provide support for further investigation of futibatinib across other indications. Future directions for this agent include elucidating mechanisms of resistance and exploration of combination therapy approaches.