Regorafenib: A Review in Hepatocellular Carcinoma

Vascular endothelial growth factor signaling in health and disease: from molecular mechanisms to therapeutic perspectives

Vascular endothelial growth factor (VEGF) signaling is a critical regulator of vasculogenesis, angiogenesis, and lymphangiogenesis, processes that are vital for the development of vascular and lymphatic systems, tissue repair, and the maintenance of homeostasis. VEGF ligands and their receptors orchestrate endothelial cell proliferation, migration, and survival, playing a pivotal role in dynamic vascular remodeling. Dysregulated VEGF signaling drives diverse pathological conditions, including tumor angiogenesis, cardiovascular diseases, and ocular disorders. Excessive VEGF activity promotes tumor growth, invasion, and metastasis, while insufficient signaling contributes to impaired wound healing and ischemic diseases. VEGF-targeted therapies, such as monoclonal antibodies and tyrosine kinase inhibitors, have revolutionized the treatment of diseases involving pathological angiogenesis, offering significant clinical benefits in oncology and ophthalmology. These therapies inhibit angiogenesis and slow disease progression, but they often face challenges such as therapeutic resistance, suboptimal efficacy, and adverse effects. To further explore these issues, this review provides a comprehensive overview of VEGF ligands and receptors, elucidating their molecular mechanisms and regulatory networks. It evaluates the latest progress in VEGF-targeted therapies and examines strategies to address current challenges, such as resistance mechanisms. Moreover, the discussion includes emerging therapeutic strategies such as innovative drug delivery systems and combination therapies, highlighting the continuous efforts to improve the effectiveness and safety of VEGF-targeted treatments. This review highlights the translational potential of recent discoveries in VEGF biology for improving patient outcomes.

Targeting Metabolism: Innovative Therapies for MASLD Unveiled

The recent introduction of the term metabolic-dysfunction-associated steatotic liver disease (MASLD) has highlighted the critical role of metabolism in the disease's pathophysiology. This innovative nomenclature signifies a shift from the previous designation of non-alcoholic fatty liver disease (NAFLD), emphasizing the condition's progressive nature. Simultaneously, MASLD has become one of the most prevalent liver diseases worldwide, highlighting the urgent need for research to elucidate its etiology and develop effective treatment strategies. This review examines and delineates the revised definition of MASLD, exploring its epidemiology and the pathological changes occurring at various stages of the disease. Additionally, it identifies metabolically relevant targets within MASLD and provides a summary of the latest metabolically targeted drugs under development, including those in clinical and some preclinical stages. The review finishes with a look ahead to the future of targeted therapy for MASLD, with the goal of summarizing and providing fresh ideas and insights.

Progress in the Application of Novel Nanomaterials in Targeted Therapy for Liver Cancer

In recent years, nanobiotechnology, widely used in hepatoma, holds great promise for improving targeted hepatocarcinoma therapy. On account of the unique properties of low toxicity, good tolerance, biocompatibility, and biodegradability of new nanomaterials, a targeted drug delivery system (TDDS) has been constructed, which can boost the therapeutic effect of hepatoma-targeted drugs, reduce drug toxicity, and minimize off target reactions by enhancing permeability retention effect (EPR) and active targeting, thus improving existing liver cancer targeted therapy strategies. Different nanoparticles have their own advantages and disadvantages. They can be loaded with multiple drugs on the same nanoparticle and can also be surface modified with each other to achieve synergistic anti-tumor effects. This essay provides a comprehensive overview of the current status of targeted therapy for hepatocarcinoma, nanoparticles' structure, advantages and disadvantages of each nanoparticle, and the application progress of nanoparticles in targeted therapy for liver cancer. We hope to provide a basis for the future clinical targeted therapy of hepatoma using nanotechnology.

Discovery of potential VEGFR-2 inhibitors from natural products by virtual screening and molecular dynamics simulation

Hepatocellular carcinoma (HCC) is the most common cancer worldwide and vascular endothelial growth factor receptor-2 (VEGFR-2) is an important target in the development of inhibitors for the treatment of liver cancer. So far, however, there are no effective drugs targeting VEGFR-2 to achieve complete treatment of liver cancer. In this study, we employed molecular docking, molecular dynamics simulations, molecular mechanics generalized Born surface area (MM-GBSA) method, quantum mechanics/molecular mechanics (QM/MM) calculations and steered molecular dynamics simulations to discover the potential inhibitors from COCONUT database targeting VEGFR-2. The molecular docking analyses of 13 743 natural compounds targeting VEGFR-2 identified 96 molecules as promising candidates. Our molecular dynamics simulations revealed that only 5 candidate-docking systems remained stable over 100 ns of production run. Then, steered molecular dynamics simulations showed that CNP0076764, CNP0028810, CNP0177683 and CNP0107283 had higher mean force values than that of sorafenib, reflecting the high potential of candidate molecules. A detailed analysis of the binding modes revealed that Leu840, Val848, Lys868, Glu885, Leu889, Val899, Val916, Leu1035, Cys1045, Asp1046 and Phe1047 play key roles in binding the inhibitors. Overall, this study shows evidence that the four natural products obtained from the COCONUT database could be further used as anti-cancer inhibitors, which provides theoretical guidance for designing new drugs.

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.

Osteosarcoma cells depend on MCL-1 for survival, and osteosarcoma metastases respond to MCL-1 antagonism plus regorafenib in vivo

Osteosarcoma is the most common form of primary bone cancer, which primarily afflicts children and adolescents. Chemotherapy, consisting of doxorubicin, cisplatin and methotrexate (MAP) increased the 5-year osteosarcoma survival rate from 20% to approximately 60% by the 1980s. However, osteosarcoma survival rates have remained stagnant for several decades. Patients whose disease fails to respond to MAP receive second-line treatments such as etoposide and, in more recent years, the kinase inhibitor regorafenib. BCL-2 and its close relatives enforce cellular survival and have been implicated in the development and progression of various cancer types. BH3-mimetics antagonize pro-survival members of the BCL-2 family to directly stimulate apoptosis. These drugs have been proven to be efficacious in other cancer types, but their use in osteosarcoma has been relatively unexplored to date. We investigated the potential efficacy of BH3-mimetics against osteosarcoma cells in vitro and examined their cooperation with regorafenib in vivo. We demonstrated that osteosarcoma cell lines could be killed through inhibition of MCL-1 combined with BCL-2 or BCL-xL antagonism. Inhibition of MCL-1 also sensitized osteosarcoma cells to killing by second-line osteosarcoma treatments, particularly regorafenib. Importantly, we found that inhibition of MCL-1 with the BH3-mimetic S63845 combined with regorafenib significantly prolonged the survival of mice bearing pulmonary osteosarcoma metastases. Together, our results highlight the importance of MCL-1 in osteosarcoma cell survival and present a potential therapeutic avenue that may improve metastatic osteosarcoma patient outcomes.

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.

The cumulative antitumor effects of regorafenib and radiotherapy in hepatocellular carcinoma

Regorafenib is a second-line standard treatment for hepatocellular carcinoma (HCC). However, the efficacy of regorafenib is often limited due to drug resistance, individual differences among patients, and irrational drug use. Radiotherapy (RT) is an important method of localized HCC treatment, and combining RT with other therapies may exert a synergetic antitumor effect. Platelet-derived growth factor receptor-like (PDGFRL) is a tumor suppressor in various solid tumors. However, the function of PDGFRL in HCC is still unknown. In this study, we explored whether regorafenib and RT exert a synergetic effect on the treatment of HCC. The antitumor effect and mechanisms of the combination of regorafenib and RT were verified in a xenograft mouse model in vivo and in HCC cells in vitro. The combination treatment significantly inhibited cell proliferation and promoted apoptosis both in vitro and in vivo. PDGFRL, a potential target of regorafenib, was increased after cumulative treatment in HCC cells, and PDGFRL suppressed HCC cell proliferation and promoted apoptosis by inhibiting STAT3 pathway activation. Furthermore, the cumulative antitumor effect was dependent on the upregulated expression of PDGFRL and inhibition of STAT3 signaling pathway activation in HCC cells. This study increased the understanding of the molecular mechanism underlying the effect of regorafenib plus RT on HCC and provided a theoretical basis for the clinical practice of HCC.

CuET overcomes regorafenib resistance by inhibiting epithelial-mesenchymal transition through suppression of the ERK pathway in hepatocellular carcinoma

BACKGROUND AND PURPOSE

Regorafenib was approved by the US Food and Drug Administration (FDA) for hepatocellular carcinoma (HCC) patients showing progress on sorafenib treatment. However, there is an inevitably high rate of drug resistance associated with regorafenib, which reduces its effectiveness in clinical treatment. Thus, there is an urgent need to find a potential way to solve the problem of regorafenib resistance. The metabolite of disulfiram complexed with copper, the Diethyldithiocarbamate-copper complex (CuET), has been found to be an effective anticancer drug candidate. In the present study, we aimed to evaluate the effect of CuET on regorafenib resistance in HCC and uncover the associated mechanism.

EXPERIMENTAL APPROACH

Regorafenib-resistant HCC strains were constructed by applying an increasing concentration gradient. This study employed a comprehensive range of methodologies, including the cell counting kit-8 (CCK-8) assay, colony formation assay, cell cycle analysis, wound healing assay, Transwell assay, tumor xenograft model, and immunohistochemical analysis. These methods were utilized to investigate the antitumor activity of CuET, assess the combined effect of regorafenib and CuET, and elucidate the molecular mechanism underlying CuET-mediated regorafenib resistance.

KEY RESULTS

The inhibitory effect of regorafenib on cell survival, proliferation and migration was decreased in regorafenib-resistant MHCC-97H (MHCC-97H/REGO) cells compared with parental cells. CuET demonstrated significant inhibitory effects on cell survival, proliferation, and migration of various HCC cell lines. CuET restored the sensitivity of MHCC-97H/REGO HCC cells to regorafenib in vitro and in vivo. Mechanistically, CuET reverses regorafenib resistance in HCC by suppressing epithelial-mesenchymal transition (EMT) through inhibition of the ERK signaling pathway.

CONCLUSION AND IMPLICATIONS

Taken together, the results of this study demonstrated that CuET inhibited the activation of the ERK signaling pathway, leading to the suppression of the epithelial-mesenchymal transition (EMT) and subsequently reversing regorafenib resistance in HCC both in vivo and in vitro. This study provides a new idea and potential strategy to improve the treatment of regorafenib-resistant HCC.

Underlying mechanisms and management strategies for regorafenib-induced toxicity in hepatocellular carcinoma

INTRODUCTION

Hepatocellular carcinoma (HCC) accounts for 85% of liver cancer cases and is the third leading cause of cancer death. Regorafenib is a multi-target inhibitor that dramatically prolongs progression-free survival in HCC patients who have failed sorafenib therapy. However, one of the primary factors limiting regorafenib's clinical utilization is toxicity. Using Clinical Trials.gov and PubMed, we gathered clinical data on regorafenib and conducted a extensive analysis of the medication's adverse reactions and mechanisms. Next, we suggested suitable management techniques to improve regorafenib's effectiveness.

AREAS COVERED

We have reviewed the mechanisms by which regorafenib-induced toxicity occurs and general management strategies through clinical trials of regorafenib. Furthermore, by examining the literature on regorafenib and other tyrosine kinase inhibition, we summarized the mechanics of the onset of regorafenib toxicity and mechanism-based intervention strategies by reviewing the literature related to regorafenib and other tyrosine kinase inhibition.

EXPERT OPINION

One of the primary factors restricting regorafenib's clinical utilization and combination therapy is its toxicity reactions. To optimize regorafenib treatment regimens, it is especially important to further understand the specific toxicity mechanisms of regorafenib as a multi-kinase inhibitor.

Pericytes: jack-of-all-trades in cancer-related inflammation

Pericytes, recognized as mural cells, have long been described as components involved in blood vessel formation, playing a mere supporting role for endothelial cells (ECs). Emerging evidence strongly suggests their multifaceted roles in tissues and organs. Indeed, pericytes exhibit a remarkable ability to anticipate endothelial cell behavior and adapt their functions based on the specific cells they interact with. Pericytes can be activated by pro-inflammatory stimuli and crosstalk with immune cells, actively participating in their transmigration into blood vessels. Moreover, they can influence the immune response, often sustaining an immunosuppressive phenotype in most of the cancer types studied. In this review, we concentrate on the intricate crosstalk between pericytes and immune cells in cancer, highlighting the primary evidence regarding pericyte involvement in primary tumor mass dynamics, their contributions to tumor reprogramming for invasion and migration of malignant cells, and their role in the formation of pre-metastatic niches. Finally, we explored recent and emerging pharmacological approaches aimed at vascular normalization, including novel strategies to enhance the efficacy of immunotherapy through combined use with anti-angiogenic drugs.

Regorafenib plus programmed death‑1 inhibitors vs. regorafenib monotherapy in second‑line treatment for advanced hepatocellular carcinoma: A systematic review and meta‑analysis

The present study compared the efficacy and safety of regorafenib plus programmed death-1 inhibitors (R-P) with regorafenib monotherapy as second-line therapies for advanced hepatocellular carcinoma (HCC). A systematic search of relevant literature published in PubMed, Embase, Web of Science and Cochrane Library databases until October 2023 was conducted. Two authors independently performed data extraction and screening using standardized protocols. Stata/MP 17.0 was used for the meta-analysis to evaluate the impact of R-P treatment on major outcome indicators, including overall survival, progression-free survival (PFS), tumor response and adverse reactions, in patients with advanced HCC. The results indicated that five cohort studies involving 444 patients with advanced HCC were included. The results revealed that R-P treatment improved overall survival [hazard ratio (HR), 0.61; 95% confidence interval (CI) 0.48-0.77; I2=0.0%; P=0.663] and PFS (HR, 0.51; 95% CI 0.41-0.63; I2=17.5%; P=0.303). Additionally, it increased the objective response rate (risk ratio, 2.33; 95% CI, 1.49-3.64; I2=0.0%; P=0.994) and disease control rate (HR, 1.40; 95% CI, 1.20-1.63; I2=0.0%; P=0.892) compared with those of regorafenib. However, R-P treatment was associated with an increased incidence of adverse events, such as hypothyroidism, thrombocytopenia and rash, compared with that in regorafenib. In conclusion, R-P is superior to regorafenib monotherapy in terms of survival benefits and tumor response.

Hepatocellular Carcinoma: Beyond the Border of Advanced Stage Therapy

Hepatocellular carcinoma (HCC) is the deadliest emergent health issue around the globe. The stronger oncogenic effect, proteins, and weakened immune response are precisely linked with a significant prospect of developing HCC. Several conventional systemic therapies, antiangiogenic therapy, and immunotherapy techniques have significantly improved the outcomes for early-, intermediate-, and advanced-stage HCC patients, giving new hope for effective HCC management and prolonged survival rates. Innovative therapeutic approaches beyond conventional treatments have altered the landscape of managing HCC, particularly focusing on targeted therapies and immunotherapies. The advancement in HCC treatment suggested by the Food and Drug Administration is multidimensional treatment options, including multikinase inhibitors (sorafenib, lenvatinib, regorafenib, ramucirumab, and cabozantinib) and immune checkpoint inhibitors (atezolizumab, pembrolizumab, durvalumab, tremelimumab, ipilimumab, and nivolumab), in monotherapy and in combination therapy to increase life expectancy of HCC patients. This review highlights the efficacy of multikinase inhibitors and immune checkpoint inhibitors in monotherapy and combination therapy through the analysis of phase II, and III clinical trials, targeting the key molecular pathways involved in cellular signaling and immune response for the prospective treatment of advanced and unresectable HCC and discusses the upcoming combinations of immune checkpoint inhibitors-tyrosine kinase inhibitors and immune checkpoint inhibitors-vascular endothelial growth factor inhibitors. Finally, the hidden challenges with pharmacological therapy for HCC, feasible solutions for the future, and implications of possible presumptions to develop drugs for HCC treatment are reported.

Precision targeting in hepatocellular carcinoma: Exploring ligand-receptor mediated nanotherapy

Hepatocellular carcinoma (HCC) is the most common primary liver cancer and poses a major challenge to global health due to its high morbidity and mortality. Conventional chemotherapy is usually targeted to patients with intermediate to advanced stages, but it is often ineffective and suffers from problems such as multidrug resistance, rapid drug clearance, nonspecific targeting, high side effects, and low drug accumulation in tumor cells. In response to these limitations, recent advances in nanoparticle-mediated targeted drug delivery technologies have emerged as breakthrough approaches for the treatment of HCC. This review focuses on recent advances in nanoparticle-based targeted drug delivery systems, with special attention to various receptors overexpressed on HCC cells. These receptors are key to enhancing the specificity and efficacy of nanoparticle delivery and represent a new paradigm for actively targeting and combating HCC. We comprehensively summarize the current understanding of these receptors, their role in nanoparticle targeting, and the impact of such targeted therapies on HCC. By gaining a deeper understanding of the receptor-mediated mechanisms of these innovative therapies, more effective and precise treatment of HCC can be achieved.

Pyrrolo[2,3-D]Pyrimidines as EGFR and VEGFR Kinase Inhibitors: A Comprehensive SAR Review

Tyrosine kinases are implicated in a wide array of cellular physiological processes, including cell signaling. The discovery of the BCR-ABL tyrosine kinase inhibitor imatinib and its FDA approval in 2001 paved the way for the development of small molecule chemical entities of diverse structural backgrounds as tyrosine kinase inhibitors for the treatment of various ailments. Two of the most prominent tyrosine kinases as drug targets are the epidermal growth factor receptor (EGFR) and the vascular endothelial growth factor receptor (VEGFR), as evidenced by the clinical success of their many inhibitors in the drug market. Among several other physiological roles, EGFR regulates epithelial tissue development and homeostasis, while VEGFR regulates tumor-induced angiogenesis. The pyrrolo[2,3-d]pyrimidine nucleus represents a deaza-isostere of adenine, the nitrogenous base of ATP. The recent introduction of many pyrrolo[2,3-d]pyrimidines to the drug market as tyrosine kinase inhibitors makes them a hot topic in the medicinal chemistry research area at the present time. This review article comprehensively sheds light on the structure-activity relationship (SAR) of pyrrolo[2,3-d]pyrimidines as EGFR and VEGFR tyrosine kinase inhibitors, aiming to provide help medicinal chemists in the design of future pyrrolopyrimidine kinase inhibitors.

A feedback loop of PPP and PI3K/AKT signal pathway drives regorafenib-resistance in HCC

BACKGROUND

Hepatocellular carcinoma (HCC) is a principal type of liver cancer with high incidence and mortality rates. Regorafenib is a novel oral multikinase inhibitor for second-line therapy for advanced HCC. However, resistance to regorafenib is gradually becoming a dilemma for HCC and the mechanism remains unclear. In this study, we aimed to reveal the metabolic profiles of regorafenib-resistant cells and the key role and mechanism of the most relevant metabolic pathway in regorafenib resistance.

METHODS

Metabolomics was performed to detect the metabolic alteration between drug-sensitive and regorafenib-resistant cells. Colony formation assay, CCK-8 assay and flow cytometry were applied to observe cell colony formation, cell proliferation and apoptosis, respectively. The protein and mRNA levels were detected by western blot and RT-qPCR. Cell lines of Glucose-6-phosphate dehydrogenase(G6PD) knockdown in regorafenib-resistant cells or G6PD overexpression in HCC cell lines were stably established by lentivirus infection technique. G6PD activity, NADPH level, NADPH/NADP+ ratio, the ratio of ROS positive cells, GSH level, and GSH/GSSG ratio were detected to evaluate the anti-oxidative stress ability of cells. Phosphorylation levels of NADK were evaluated by immunoprecipitation.

RESULTS

Metabonomics analysis revealed that pentose phosphate pathway (PPP) was the most relevant metabolic pathway in regorafenib resistance in HCC. Compared with drug-sensitive cells, G6PD enzyme activity, NADPH level and NADPH/NADP+ ratio were increased in regorafenib-resistant cells, but the ratio of ROS positive cells and the apoptosis rate under the conditions of oxidative stress were decreased. Furthermore, G6PD suppression using shRNA or an inhibitor, sensitized regorafenib-resistant cells to regorafenib. In contrast, G6PD overexpression blunted the effects of regorafenib to drug-sensitive cells. Mechanistically, G6PD, the rate-limiting enzyme of PPP, regulated the PI3K/AKT activation. Furthermore, PI3K/AKT inhibition decreased G6PD protein expression, G6PD enzymatic activity and the capacity of PPP to anti-oxidative stress possibly by inhibited the expression and phosphorylation of NADK.

CONCLUSION

Taken together, a feedback loop of PPP and PI3K/AKT signal pathway drives regorafenib-resistance in HCC and targeting the feedback loop could be a promising approach to overcome drug resistance.

The Complexity of the Tumor Microenvironment in Hepatocellular Carcinoma and Emerging Therapeutic Developments

This review explores various aspects of the HCC TME, including both cellular and non-cellular components, to elucidate their roles in tumor development and progression. Specifically, it highlights the significance of cancer-associated fibroblasts (CAFs) and their contributions to tumor progression, angiogenesis, immune suppression, and therapeutic resistance. Moreover, this review emphasizes the role of immune cells, such as tumor-associated macrophages (TAMs), myeloid-derived suppressor cells (MDSCs), and regulatory T-cells (Tregs), in shaping the immunosuppressive microenvironment that promotes tumor growth and immune evasion. Furthermore, we also focused only on the non-cellular components of the HCC TME, including the extracellular matrix (ECM) and the role of hypoxia-induced angiogenesis. Alterations in the composition of ECM and stiffness have been implicated in tumor invasion and metastasis, while hypoxia-driven angiogenesis promotes tumor growth and metastatic spread. The molecular mechanisms underlying these processes, including the activation of hypoxia-inducible factors (HIFs) and vascular endothelial growth factor (VEGF) signaling, are also discussed. In addition to elucidating the complex TME of HCC, this review focuses on emerging therapeutic strategies that target the TME. It highlights the potential of second-line treatments, such as regorafenib, cabozantinib, and ramucirumab, in improving overall survival for advanced HCC patients who have progressed on or were intolerant to first-line therapy. Furthermore, this review explores the implications of the Barcelona Clinic Liver Cancer (BCLC) staging and classification system in guiding HCC management decisions. The BCLC system, which incorporates tumor stage, liver function, and performance status, provides a framework for treatment stratification and prognosis prediction in HCC patients. The insights gained from this review contribute to the development of novel therapeutic interventions and personalized treatment approaches for HCC patients, ultimately improving clinical outcomes in this challenging disease.

β-HB treatment reverses sorafenib resistance by shifting glycolysis-lactate metabolism in HCC

Hepatocellular carcinoma (HCC) is the most common primary malignant tumor. Although sorafenib and regorafenib have been approved for first-line and second-line treatment, respectively, of patients with advanced HCC, long-term treatment often results in acquired resistance. Given that glycolysis-mediated lactate production can contribute to drug resistance and impair HCC treatment efficacy, we investigated the effects of ketone body treatment on the metabolic shift in sorafenib-resistant HCC cells. We discovered differential expression of 3-hydroxymethyl glutaryl-CoA synthase 2 (HMGCS2) and the ketone body D-β-hydroxybutyrate (β-HB) in four sorafenib-resistant HCC cell lines. In sorafenib-resistant HCC cells, lower HMGCS2 and β-HB levels were correlated with more glycolytic alterations and higher lactate production. β-HB treatment enhanced pyruvate dehydrogenase (PDH) expression and decreased lactate dehydrogenase (LDHA) expression and lactate production in sorafenib-resistant HCC cells. Additionally, β-HB combined with sorafenib or regorafenib promoted the antiproliferative and antimigratory abilities of sorafenib-resistant HCC cells by inhibiting the B-raf/mitogen-activated protein kinase pathway and mesenchymal N-cadherin-vimentin axis. Although the in vivo β-HB administration did not affect tumor growth, the expression of proliferative and glycolytic proteins was inhibited in subcutaneous sorafenib-resistant tumors. In conclusion, exogenous β-HB treatment can reduce lactate production and reverse sorafenib resistance by inducing a glycolytic shift; it can also synergize with regorafenib for treating sorafenib-resistant HCC.

Eastern Canadian Gastrointestinal Cancer Consensus Conference 2023

The annual Eastern Canadian Gastrointestinal Cancer Consensus Conference 2023 was held in Quebec City, Quebec 2-4 February 2023. The purpose of the conference was to develop consensus statements on emerging and evolving treatment paradigms. Participants included Canadian medical oncologists, radiation oncologists, pathologists and surgical oncologists from across Ontario, Quebec, and the Atlantic provinces. Consensus statements were developed following rapid review presentations and discussion of available literature. The recommendations proposed here represent the consensus opinions of physicians involved in the care of patients with gastrointestinal malignancies who participated in this meeting.

Research and development of N,N'-diarylureas as anti-tumor agents

Tumor neovascularization provides abundant nutrients for the occurrence and development of tumors, and is also an important factor in tumor invasion and metastasis, which has attracted extensive attention in anti-tumor therapy. Sorafenib is a clinically approved multi-targeted anti-tumor drug that targets vascular endothelial growth factor receptor (VEGFR) and inhibits the formation of tumor angiogenesis, thereby achieving the purpose of suppressing tumor growth. Since the approval of sorafenib, N,N'-diarylureas have received extensive attention as the key pharmacophore in its chemical structure. And a series of N,N'-diarylureas were designed and synthesized to screen a new generation of anti-tumor drug candidates through chemical modification and structural optimization. Moreover, the rational design of targeted drugs is beneficial to reduce toxic side effects and drug resistance and improve the curative effect. Here, this article reviews the research progress in the design, classification, structure-activity relationship (SAR) and biological activity of N,N'-diarylureas, in order to provide some prospective routes for the development of clinically effective anti-tumor drugs.

Discovery of a new potent oxindole multi-kinase inhibitor among a series of designed 3-alkenyl-oxindoles with ancillary carbonic anhydrase inhibitory activity as antiproliferative agents

An optimization strategy was adopted for designing and synthesizing new series of 2-oxindole conjugates. Selected compounds were evaluated for their antiproliferative effect in vitro against NCI-60 cell lines panel, inhibitory effect on carbonic anhydrase (CA) isoforms (hCAI, II, IX and XII), and protein kinases. Compounds 5 and 7 showed promising inhibitory effects on hCA XII, whereas compound 4d was the most potent inhibitor with low nanomolar CA inhibition against all tested isoforms. These results were rationalized by using molecular docking. Despite its lack of CA inhibitory activity, compound 15c was the most active antiproliferative candidate against most of the 60 cell lines with mean growth inhibition 61.83% and with IC₅₀ values of 4.39, 1.06, and 0.34 nM against MCT-7, DU 145, and HCT-116 cell lines, respectively. To uncover the mechanism of action behind its antiproliferative activity, compound 15c was assessed against a panel of protein kinases (RET, KIT, cMet, VEGFR1,2, FGFR1, PDFGR and BRAF) showing % inhibition of 74%, 31%, 62%, 40%, 73%, 74%, 59%, and 69%, respectively, and IC₅₀ of 1.287, 0.117 and 1.185 μM against FGFR1, VEGFR, and RET kinases, respectively. These results were also explained through molecular docking.

Conversion of primary liver cancer after targeted therapy for liver cancer combined with AFP-targeted CAR T-cell therapy: a case report

Primary liver cancer (PLC) that originates in the liver is a malignant tumor with the worst prognosis. Hepatocellular carcinoma (HCC) is the most common type of PLC. Most PLC cases are diagnosed at advanced stages mainly due to their insidious onset and rapid progression. Patients with PLC undergo surgical intervention or localized treatment, but their survival is often affected by its high relapse rate. Medical treatment is the primary option for patients with liver cancer, especially with advanced extrahepatic metastases. Molecular targeted therapy exerts an anti-tumor effect by acting on various signaling pathways involved in molecular pathogenesis; however, high drug resistance and low therapeutic responsiveness of PLC to molecular targets challenge the treatment option. In recent years, after surgical intervention, radiotherapy, chemotherapy, and/or molecular targeted therapy, autologous cell immunotherapy has been adopted for PLC. As a typical autologous cell immunotherapy, CAR T-cell therapy uses genetically modified T cells to express tumor-specific chimeric antigen receptors (CARs). Its targeting ability, persistent nature, and tumor-killing function result in a significant impact on the treatment of hematological tumors. However, no breakthrough has happened in the research specific to the curation of lung cancer, liver cancer, breast cancer, and other common solid tumors. In this context, a combination of molecular targeted therapy and CAR T-cell therapy was used to treat a patient with advanced HCC to achieve a partial remission(PR) and facilitate further liver transplantation.

Eupalinolide A induces autophagy via the ROS/ERK signaling pathway in hepatocellular carcinoma cells in vitro and in vivo

Hepatocellular carcinoma is the most common primary malignancy of the liver. The current systemic drugs used to treat hepatocellular carcinoma result in low overall survival time. It has therefore been suggested that new small‑molecule drugs should be developed for treating hepatocellular carcinoma. Eupatorium lindleyanum DC. (EL) has been used to treat numerous diseases, particularly respiratory diseases; however, to the best of our knowledge, studies have not yet fully elucidated the effect of EL on hepatocellular carcinoma. In the present study, the effect of eupalinolide A (EA), one of the extracts of EL, was evaluated on tumor growth in a xenograft model of human hepatocellular carcinoma cells, and on the proliferation and migration of hepatocellular carcinoma cell lines. Cell cycle progression and the type of cell death were then evaluated using the Cell Counting Kit 8 assay, flow cytometry, electron microscopy and western blotting. EA significantly inhibited cell proliferation and migration by arresting the cell cycle at the G1 phase and inducing autophagy in hepatocellular carcinoma cells. EA‑induced autophagy was mediated by reactive oxygen species (ROS) and ERK signaling activation. Specific inhibitors of ROS, autophagy and ERK inhibited EA‑induced cell death and migration. In conclusion, the present study revealed that EA may inhibit the proliferation and migration of hepatocellular carcinoma cells, highlighting its potential as a promising antitumor compound for treating hepatocellular carcinoma.

Urea-based anticancer agents. Exploring 100-years of research with an eye to the future

Suramin was the first urea-based drug to be approved in clinic, and in the following century a number of milestone drugs based on this scaffold were developed. Indeed, urea soon became a privileged scaffold in medicinal chemistry for its capability to establish a peculiar network of drug-target interactions, for its physicochemical properties that are useful for tuning the druggability of the new chemical entities, and for its structural and synthetic versatility that opened the door to numerous drug design possibilities. In this review, we highlight the relevance of the urea moiety in the medicinal chemistry scenario of anticancer drugs with a special focus on the kinase inhibitors for which this scaffold represented and still represents a pivotal pharmacophoric feature. A general outlook on the approved drugs, recent patents, and current research in this field is herein provided, and the role of the urea moiety in the drug discovery process is discussed form a medicinal chemistry standpoint. We believe that the present review can benefit both academia and pharmaceutical companies' medicinal chemists to prompt research towards new urea derivatives as anticancer agents.

A high throughput method for Monitoring of Sorafenib, regorafenib, cabozantinib and their metabolites with UPLC-MS/MS in rat plasma

As multi-targeted tyrosine kinase inhibitors, sorafenib, regorafenib and cabozantinib are widely used in hepatocellular carcinoma (HCC) for systemic therapies with anti-proliferative and anti-angiogenic effects. Nevertheless, adverse effects or insufficient efficacy appear frequently due to the plasma concentration with individual variability of these drugs. To ensure the curative effect and safety by therapeutic drug monitoring (TDM), this study developed a high throughput method to quantify sorafenib, regorafenib, cabozantinib and their active metabolites in plasma simultaneously. The chromatographic separation analysis achievement was performed on a Waters-ACQUITY UPLC BEH C18 column by UPLC-MS/MS system using a gradient elution of solvent A (acetonitrile) and solvent B (water with 0.1% formic acid) in 3.0 min. This method presented satisfactory results of specificity, precision (the intra-day coefficient of variation was between 2.5% and 6.6%, and the inter-day coefficient of variation was between 4.0% and 11.1%) and accuracy (within ±15% for intra-day and inter-day), as well as the stability under certain conditions, the matrix effect in plasma, and extraction recovery (75.6%–94.4%). The linearity of each analyte in the proper concentration scope indicated excellent. This study strictly complied with the performance rules of assay validation in biological medium proposed by FDA and was successfully applied to the pharmacokinetic study in rats. Thus, it would be an advantageous option to research the relationship between concentration-efficacy and concentration-toxic in HCC patients who were supposed to take these medications.

Inducing vascular normalization: A promising strategy for immunotherapy

In solid tumors, the vasculature is highly abnormal in structure and function, resulting in the formation of an immunosuppressive tumor microenvironment by limiting immune cells infiltration into tumors. Vascular normalization is receiving much attention as an alternative strategy to anti-angiogenic therapy, and its potential therapeutic targets include signaling pathways, angiogenesis-related genes, and metabolic pathways. Endothelial cells play an important role in the formation of blood vessel structure and function, and their metabolic processes drive blood vessel sprouting in parallel with the control of genetic signals in cancer. The feedback loop between vascular normalization and immunotherapy has been discussed extensively in many reviews. In this review, we summarize the impact of aberrant tumor vascular structure and function on drug delivery, metastasis, and anti-tumor immune responses. In addition, we present evidences for the mutual regulation of immune vasculature. Based on the importance of endothelial metabolism in controlling angiogenesis, we elucidate the crosstalk between endothelial cells and immune cells from the perspective of metabolic pathways and propose that targeting abnormal endothelial metabolism to achieve vascular normalization can be an alternative strategy for cancer treatment, which provides a new theoretical basis for future research on the combination of vascular normalization and immunotherapy.

Two important factors affecting the prognosis of patients treated with sorafenib followed by regorafenib for advanced hepatocellular carcinoma

Objective

To investigate the effects of hand–foot syndrome (HFS) and fatigue on disease progression and survival in patients treated with sorafenib followed by regorafenib for advanced hepatocellular carcinoma.

Methods

A retrospective analysis of patients with advanced hepatocellular carcinoma treated with sorafenib in our hospital from 1 October 2018 to 31 October 2021 was performed, and clinical and pathological data and follow-up results were obtained. Patients were divided into groups according to the severity of HFS and fatigue. Survival analysis among the groups was performed using the Kaplan–Meier method, continuous variables were analyzed using the t-test, and factors associated with survival were evaluated using multivariate Cox regression analysis.

Results

The study included 150 men and 23 women with a mean age of 60.77 years (range: 40–85 years). The median overall survival (OS), progression-free survival (PFS), and time to tumor progression (TTP) increased with increasing severity of HFS. Conversely, the median OS, PFS, and TTP decreased with increasing severity of fatigue

Conclusion

HFS and fatigue were independent risk factors affecting TTP, PFS, and OS among patients treated with sorafenib followed by regorafenib for advanced hepatocellular carcinoma.

FOXM1-CD44 Signaling Is Critical for the Acquisition of Regorafenib Resistance in Human Liver Cancer Cells

Regorafenib is a multikinase inhibitor that was approved by the US Food and Drug administration in 2017. Cancer stem cells (CSCs) are a small subset of cancer-initiating cells that are thought to contribute to therapeutic resistance. The forkhead box protein M1 (FOXM1) plays an important role in the regulation of the stemness of CSCs and mediates resistance to chemotherapy. However, the relationship between FOXM1 and regorafenib resistance in liver cancer cells remains unknown. We found that regorafenib-resistant HepG2 clones overexpressed FOXM1 and various markers of CSCs. Patients with hepatocellular carcinoma also exhibited an upregulation of FOXM1 and resistance to regorafenib, which were correlated with a poor survival rate. We identified a close relationship between FOXM1 expression and regorafenib resistance, which was correlated with the survival of patients with hepatocellular carcinoma. Thus, a strategy that antagonizes FOXM1–CD44 signaling would enhance the therapeutic efficacy of regorafenib in these patients.

Mechanisms of resistance to tyrosine kinase inhibitors in liver cancer stem cells and potential therapeutic approaches

The administration of tyrosine kinase inhibitors (TKIs) for the treatment of advanced-stage patients is common in hepatocellular carcinoma (HCC). However, therapy resistance is often encountered, and its emergence eventually curtails long-term clinical benefits. Cancer stem cells (CSCs) are essential drivers of tumor recurrence and therapy resistance; thus, the elucidation of key hallmarks of resistance mechanisms of liver CSC-driven HCC may help improve patient outcomes and reduce relapse. The present review provides a comprehensive summary of the intrinsic and extrinsic mechanisms of TKI resistance in liver CSCs, which mediate treatment failure, and discusses potential strategies to overcome TKI resistance from a preclinical perspective.

Real-Life Experience of Regorafenib in Patients With Advanced Hepatocellular Carcinoma

Background: The RESORCE trial reported that regorafenib was effective as the second-line treatment for patients with hepatocellular carcinoma (HCC) after progression on sorafenib. Real-world data are needed to assess clinical outcomes and adverse events in the setting of daily practice.

Objective: We aimed to evaluate the efficacy and safety of regorafenib after disease progression with sorafenib in Chinese patients with advanced HCC.

Patients and Methods: A total of 41 patients with advanced HCC who did not respond to sorafenib and followed a regorafenib regimen were enrolled in this retrospective study. Overall survival (OS), progression-free survival (PFS), radiological responses, and adverse events (AEs) were evaluated. Survival curves were compared by using the log-rank test and constructed with the Kaplan–Meier method.

Results: The median PFS with regorafenib was 6.6 months (range: 5.0–8.2 months), and the median OS with regorafenib was not reached. The 1-year OS rate of regorafenib was 66.4%. The median OS of sequential sorafenib to regorafenib treatment was 35.3 months [95% confidence interval (CI), 24.3–46.3], and the 2-year OS rate of sequential sorafenib to regorafenib treatment was 74.4%. The most common AEs of regorafenib treatment were elevated aspartate aminotransferase [17/41 patients (41.5%)], elevated alanine aminotransferase [16/41 patients (39%)] and hand-foot syndrome [14/41 patients (34.1%)].

Conclusion: Regorafenib appears to be safe and clinically effective in patients with advanced HCC who progressed on first-line sorafenib.

Efficacy and safety of sequential therapy with sorafenib and regorafenib for advanced hepatocellular carcinoma: a two-center study in China

BACKGROUND

Regorafenib is a standard 2nd-line treatment for patients with advanced hepatocellular carcinoma (HCC), but the efficacy and safety of sequential therapy with sorafenib and regorafenib among advanced HCC patients in China is not clear.

METHODS

This was a retrospective, two-center, cohort study of advanced HCC patients who received sequential therapy of sorafenib and regorafenib from October 2018 to April 2020 at 2 Chinese institutions. The patients were converted directly to regorafenib after failing to respond to sorafenib monotherapy. The patients underwent evaluations every 4-6 weeks to determine the efficacy and safety of the treatment according to physiological, laboratory, and radiological results. A radiological evaluation using computed tomography or magnetic resonance imaging scans was conducted. The outcomes included overall survival (OS) and progression-free survival (PFS).

RESULTS

A total of 43 patients received regorafenib as a 2nd-line treatment after sorafenib progression. Of these patients, 26 (60.5%) and 17 (39.5%) were diagnosed with Barcelona Clinic Liver Cancer (BCLC) stages B and C, respectively. The median PFS was 11.0 [95% confidence interval (CI): 5.8-16.2] months, and the median OS was 17.0 (95% CI: 12.8-21.2) months. Conversely, the most common toxicities were hand-foot skin reaction (48.8%), diarrhea (32.6%), and hypertension (14%). The most common grade 3-4 toxicities were hypoalbuminemia (4.7%), anemia (4.7%), and thrombocytopenia (4.7%). Alpha-fetoprotein (AFP) ≥400, alanine transaminase (ALT) ≥60 IU/L, and aspartate aminotransferase (AST) ≥60 IU/L before 2nd-line treatment were associated with PFS in the univariable analyses. The Cox proportional-hazards regression analysis showed that AFP [hazard ratio (HR) =0.225; 95% CI: 0.073-0.688; P=0.009], ALT (HR =0.195; 95% CI: 0.051-0.741; P=0.016), AST (HR =0.209; 95% CI: 0.063-0.697; P=0.011), and presence of extrahepatic metastasis (HR =0.074; 95% CI: 0.009-0.608; P=0.015) before 2nd-line treatment were independently associated with PFS.

CONCLUSIONS

The sequential therapy of sorafenib and regorafenib is well-tolerated and effective in advanced HCC patients after sorafenib progression based on our two-center real-world data. Patients with good liver function reserve and a high level of AFP before 2nd-line treatment may benefit from sequential treatment. These results still need further validation.

Chimeric HDAC and the cytoskeleton inhibitor broxbam as a novel therapeutic strategy for liver cancer

Broxbam, also known as N-hydroxy-4-{1-methoxy-4-[4′-(3′-bromo-4′,5′-dimethoxyphenyl)-oxazol-5′-yl]-2-phenoxy} butanamide, is a novel chimeric inhibitor that contains two distinct pharmacophores in its molecular structure. It has been previously demonstrated to inhibit the activity of histone deacetylases (HDAC) and tubulin polymerisation, two critical components required for cancer growth and survival. In the present study, the potential suitability of broxbam for the treatment of liver cancer was investigated. The effects of broxbam on cell proliferation and apoptosis, in addition to the under-lying molecular mechanism of action, were first investigated in primary liver cancer cell lines Huh7, HepG2, TFK1 and EGI1. Real-time proliferation measurements made using the iCEL-Ligence system and viable cell number counting following crystal violet staining) revealed that broxbam time- and dose-dependently reduced the proliferation of liver cancer cell lines with IC₅₀ values <1 µM. In addition, a significant inhibition of the growth of hepatoblastoma microtumours on the chorioallantoic membranes (CAM) of fertilised chicken eggs by broxbam was observed according to results from the CAM assay, suggesting antineoplastic potency in vivo. Broxbam also exerted apoptotic effects through p53- and mitochondria-driven caspase-3 activation in Huh7 and HepG2 cells according to data from western blotting (p53 and phosphorylated p53), mitochondrial membrane potential measurements (JC-1 assay) and fluorometric capsase-3 measurements. Notably, no contribution of unspecific cytotoxic effects mediated by broxbam were observed from LDH-release measurements. HDAC1, -2, -4 and -6 expression was measured by western blotting and the HDAC inhibitory potency of broxbam was next evaluated using subtype-specific HDAC enzymatic assays, which revealed a largely pan-HDAC inhibitory activity with the most potent inhibition observed on HDAC6. Silencing HDAC6 expression in Huh7 cells led to a drop in the expression of the proliferation markers Ki-67 and E2F3, suggesting that HDAC6 inhibition by broxbam may serve a predomi-nant role in their antiproliferative effects on liver cancer cells. Immunofluorescence staining of cytoskeletal proteins (α-tubulin & actin) of broxbam-treated HepG2 cells revealed a pronounced inhibition of tubulin polymerisation, which was accompanied by reduced cell migration as determined by wound healing scratch assays. Finally, data from zebrafish angiogenesis assays revealed marked antiangiogenic effects of broxbam in vivo, as shown by the suppression of subintestinal vein growth in zebrafish embryos. To conclude, the pleiotropic anticancer activities of this novel chimeric HDAC- and tubulin inhibitor broxbam suggest that this compound is a promising candidate for liver cancer treatment, which warrants further pre-clinical and clinical evaluation.

Tumor Microenvironment of Hepatocellular Carcinoma: Challenges and Opportunities for New Treatment Options

The prevalence of liver cancer is constantly rising, with increasing incidence and mortality in Europe and the USA in recent decades. Among the different subtypes of liver cancers, hepatocellular carcinoma (HCC) is the most commonly diagnosed liver cancer. Besides advances in diagnosis and promising results of pre-clinical studies, HCC remains a highly lethal disease. In many cases, HCC is an effect of chronic liver inflammation, which leads to the formation of a complex tumor microenvironment (TME) composed of immune and stromal cells. The TME of HCC patients is a challenge for therapies, as it is involved in metastasis and the development of resistance. However, given that the TME is an intricate system of immune and stromal cells interacting with cancer cells, new immune-based therapies are being developed to target the TME of HCC. Therefore, understanding the complexity of the TME in HCC will provide new possibilities to design novel and more effective immunotherapeutics and combinatorial therapies to overcome resistance to treatment. In this review, we describe the role of inflammation during the development and progression of HCC by focusing on TME. We also describe the most recent therapeutic advances for HCC and possible combinatorial treatment options.

RAB27A-dependent release of exosomes by liver cancer stem cells induces Nanog expression in their differentiated progenies and confers regorafenib resistance

BACKGROUND AND AIM

Regorafenib is a potent multikinase inhibitor for the second-line targeted therapy against hepatocellular carcinoma (HCC); however, drug resistance is emerging in clinical settings. Although cancer stem cells (CSCs) are considered as key determinate of drug sensitivity, it remains unclear how CSCs may communicate with the differentiated counterparts (non-CSC) to dictate therapeutic efficacy. Therefore, we sought to investigate the regorafenib resistance mechanism of CSCs in HCC.

METHODS

We used sphere formation and soft agar colony formation assays to evaluate the stemness capacity of cancer cells. Cell viability assay was performed to detect the sensitivity of cancer cells to regorafenib. Real-time quantitative polymerase chain reaction and western blot were used to analyze gene expression. Mouse xenograft tumor model was performed to assess Regorafenib sensitivity in vivo.

RESULTS

Exosomes are highly enriched in CSC supernatant compared with that of non-CSC, and RAB27A mediates exosome secretion from CSCs to maintain stem-like phenotype and regorafenib insensitivity. Moreover, exosomes released by CSCs upregulate the expression of Nanog in non-CSC, while depleting Nanog sensitizes non-CSC to regorafenib in the presence of CSC exosomes. Consistently, analysis of TCGA datasets reveals that RAB27A expression tightly correlates with Nanog in HCC tissues. More importantly, depletion of RAB27A downregulates Nanog expression and sensitizes cancer cells to regorafenib in nude mice.

CONCLUSIONS

Our findings suggest that CSCs release exosomes in a RAB27A-dependent manner to induce Nanog expression and regorafenib resistance in differentiated cells, targeting this exosome signaling between distinct cellular subsets may be a potential therapeutic strategy for HCC patients.

Catalpol synergistically potentiates the anti-tumour effects of regorafenib against hepatocellular carcinoma via dual inhibition of PI3K/Akt/mTOR/NF-κB and VEGF/VEGFR2 signaling pathways

BACKGROUND

Hepatocellular carcinoma (HCC) is the most common primary liver cancer characterized by dysregulation of several crucial cellular signaling pathways such as PI3K/p-Akt/mTOR/NF-κB and VEGF/VEGFR2 pathways. Novel therapies targeting these pathways have been discovered such as regorafenib which is small molecular multi-kinase inhibitor mainly targets VEGF/VEGFR2. Catalpol is an iridoid glycoside richly found in rehmannia glutinosa which is a fundamental herb used extensively in traditional Chinese medicine. It is evidenced that catalpol has many pharmacological effects on nervous and cardiovascular systems, in addition to exhibiting hypoglycemic, anti-inflammatory, anti-proliferative and anti-tumour activities. However, its effect on HCC isn't clear enough. So, this study aimed to investigate the anti-tumour effects of catalpol either alone or in combination with regorafenib on HCC.

METHODS AND RESULTS

In vitro experiments were performed using HepG2 and HUH-7 hepatocellular carcinoma cell lines. MTT assays evaluated anti-proliferative effects of catalpol and/or regorafenib. Combination index was calculated via compusyn software to detect synergism. Tumour biomarkers were measured using ELISA technique. Results showed that catalpol has anti-tumour effects against HCC via targeting PI3K/p-Akt/mTOR/NF-κB and VEGF/VEGFR2 pathways. In addition, results revealed that our novel combination of catalpol and regorafenib showed potent synergistic anti-tumour effect via suppressing both of PI3K/p-Akt/mTOR/NF-κB and VEGF/VEGFR2 signaling pathways and their downstreams.

CONCLUSION

Catalpol and/or regorafenib markedly suppressed PI3K/p-Akt/mTOR/NF-κB and VEGF/VEGFR2 signaling pathways and consequently showed potent anti-tumour effects against HCC. Results encourage further pre-clinical and clinical studies of this novel combination as a promising targeted therapy for HCC management.

Bioequivalence and Pharmacokinetic Evaluation of Two Oral Formulations of Regorafenib: An Open-Label, Randomised, Single-Dose, Two-Period, Two-Way Crossover Clinical Trial in Healthy Chinese Volunteers Under Fasting and Fed Conditions

BACKGROUND

Regorafenib is an oral multi-kinase inhibitor approved for the treatment of solid tumours, but the pharmacokinetic profile of regorafenib in the Chinese population is unclear.

OBJECTIVE

The aim of this study was to examine the pharmacokinetics, bioequivalence, and safety of two formulations of regorafenib 40 mg in healthy Chinese volunteers under fed and fasting conditions.

METHODS

A single-centre, randomised, open-label, two-period, two-way crossover phase 1 trial was conducted by randomising a single oral dose of test (T) or reference (R, Stivarga®) regorafenib (40 mg) to healthy Chinese volunteers under both fasting and fed conditions (high-fat and high-calorie diet). Pharmacokinetic parameters were calculated using non-compartmental methods. Adverse events were recorded to assess drug safety.

RESULTS

Sixty-six participants were enrolled for both fasting and fed treatments. The 90% CIs geometric least-square means of ratioT/R for regorafenib were completely contained within the equivalence margin of 80-125% under both fasting and fed conditions. Both formulations displayed similar and generally good safety profiles.

CONCLUSION

Single oral dose of the T (40 mg) and R (40 mg) regorafenib was bioequivalent under fasting and fed conditions and had similar favourable safety profiles among healthy Chinese volunteers.

Antitumor Effects of Triterpenes in Hepatocellular Carcinoma

BACKGROUND

Triterpenes are a large group of secondary metabolites mainly produced by plants with a variety of biological activities, including potential antitumor effects. Hepatocellular carcinoma (HCC) is a very common primary liver disease spread worldwide. The treatment can consist of surgical intervention, radiotherapy, immunotherapy and chemotherapeutic drugs. These drugs mainly include tyrosine multikinase inhibitors, although their use is limited by the underlying liver disease and displays side effects. For that reason, the utility of natural compounds such as triterpenes to treat HCC is an interesting line of research. No clinical studies are reported in humans so far.

OBJECTIVE

The aim of the present work is to review the knowledge about the effects of triterpenes as a possible coadjuvant tool to treat HCC.

RESULTS

In vitro and xenograft models have pointed out the cytotoxic and anti-proliferative effects as well as improvements in tumor growth and development of many triterpenes. In addition, they have also shown to be chemosensitizing agents when co-administered with chemotherapeutic agents. The mechanisms of action are diverse and involve the participation of mitogen-activated protein kinases, including JNK, p38 MAPK and ERK, and the survival-associated PI3K / Akt signaling pathway. However, no clinical studies are still reported in humans.

CONCLUSION

Triterpenes could become a future strategy to address HCC or at least improve results when administered in combination with chemotherapeutic agents.

Real-world evidence in hepatocellular carcinoma

Real-world evidence includes all health-related information, such as electronic health records, insurance claims, pharmacy records and wearables that are obtained outside of clinical trials. These data can provide critical insights into the natural history of disease and evaluate the safety and effectiveness of treatment regimens used in clinical practice. Real-world data have been applied to varying degrees by global regulatory agencies to inform and expedite many phases of drug development and help refine the use of therapeutic regimens after marketing, especially in populations that are under-represented in registration trials. For the management of hepatocellular carcinoma, early detection provides the best chance for curative therapies, whose success has been evaluated in numerous cohorts. The availability of novel systemic therapies, including kinase inhibitors and immunotherapies, has provided new treatment options and improved survival in patients with advanced stage hepatocellular carcinoma. Real-world longitudinal observational studies can help understand the long-term safety and effectiveness of these agents.

The Relationship Between Plexin C1 Overexpression and Survival in Hepatocellular Carcinoma: a Turkish Oncology Group (TOG) Study

PURPOSE

Plexin C1 is a transmembrane receptor and plexin C1 overexpression might have role in carcinogenesis. Hepatocellular carcinoma (HCC) has poor prognosis because of its aggressive behavior and limited treatment options, especially in advanced stage. We recently documented that Plexin C1 was overexpressed in HCC. We aimed to evaluate the prognostic significance of Plexin C1 overexpression in HCC in the present study.

METHODS

Plexin C1 overexpression was evaluated immunohistochemically on paraffin-embedded blocks of the HCC patients. Plexin C1 immunohistochemical staining was scored. Plexin C1 overexpression staining intensity and prevalence were used for plexin scale staining evaluation and plexin scores were estimated according this staining scale. Plexin C1 score and its association with survival and clinicopathological features was assessed.

RESULTS

Sixty-seven HCC patients with adequate tissue for pathological evaluation were included. Median age was 63 years with male predominance (male to female ratio was 4.75 (n 57/12). Well-differentiated HCC (53.7%) patients had higher plexin C1 overexpression (p < 0.05). Median OS was 22.1 months. Patients with lower plexin C1 score (< 12) had shorter OS (17.5 vs 30.1 months, p = 0.036). Neutrophil count, GGT, and PNR (platelet/neutrophil ratio) had prognostic significance (p = 0.047, p = 0.018, and p = 0.045).

CONCLUSION

Plexin C1 overexpression is inversely correlated with grade in HCC. The patients with lower rate of Plexin C1 overexpression have worse survival outcome. It might be a prognostic factor in HCC.

Evaluation of Intra-Tumoral Vascularization in Hepatocellular Carcinomas

Intratumoral neovascularization has intricate effects on tumor growth, metastasis, and treatment. Over the last 30 years, Microvessel density (MVD) has been the standard method for laboratory and clinical evaluation of angiogenesis. Hepatocellular carcinoma (HCC) is a typical hypervascularized tumor, and the predictive value of MVD for prognosis is still controversial. According to previous viewpoints, this has been attributed to the determination of hotspot, counting methods, vascular endothelial markers, and different definitions of high and low vascular density; however, the heterogeneity of tumor angiogenesis patterns should be factored. The breakthroughs in artificial intelligence and algorithm can improve the objectivity and repeatability of MVD measurement, thus saving a lot of manpower. Presently, anti-angiogenesis therapy is the only effective systematic treatment for liver cancer, and the use of imaging technology-assisted MVD measurement is expected to be a reliable index for evaluating the curative effect. MVD in multinodular hepatocellular carcinoma represents a subject area with huge understudied potential, and exploring it might advance our understanding of tumor heterogeneity.

Role of cellular, molecular and tumor microenvironment in hepatocellular carcinoma: Possible targets and future directions in the regorafenib era

Hepatocellular carcinoma (HCC) remains as one of the major causes of cancer-related mortality, despite the recent development of new therapeutic options. Regorafenib, an oral multikinase inhibitor, is the first systemic therapy that has a survival benefit for patients with advanced HCC that have a poor response to sorafenib. Even though regorafenib has been approved by the FDA, the clinical trial for regorafenib treatment does not show significant improvement in overall survival. The impaired efficacy of regorafenib caused by various resistance mechanisms, including epithelial-mesenchymal transitions, inflammation, angiogenesis, hypoxia, oxidative stress, fibrosis and autophagy, still needs to be resolved. In this review, we provide insight on regorafenib microenvironmental, molecular and cellular mechanisms and interactions in HCC treatment. The aim of this review is to help physicians select patients that would obtain the maximal benefits from regorafenib in HCC therapy.

Autophagy: A Potential Therapeutic Target of Polyphenols in Hepatocellular Carcinoma

Autophagy is a conserved biological phenomenon that maintains cellular homeostasis through the clearing of damaged cellular components under cellular stress and offers the cell building blocks for cellular survival. Aberrations in autophagy subsidize to various human pathologies, such as dementia, cardiovascular diseases, leishmaniosis, influenza, hepatic diseases, and cancer, including hepatocellular carcinoma (HCC). HCC is the fifth common mortal type of liver cancer globally, with an inhomogeneous topographical distribution and highest incidence tripled in men than women. Existing treatment procedures with liver cancer patients result in variable success rates and poor prognosis due to their drug resistance and toxicity. One of the pathophysiological mechanisms that are targeted during the development of anti-liver cancer drugs is autophagy. Generally, overactivated autophagy may lead to a non-apoptotic form of programmed cell death (PCD) or autophagic cell death or type II PCD. Emerging evidence suggests that manipulation of autophagy could induce type II PCD in cancer cells, acting as a potential tumor suppressor. Hence, altering autophagic signaling offers new hope for the development of novel drugs for the therapy of resistant cancer cells. Natural polyphenolic compounds, including flavonoids and non-flavonoids, execute their anticarcinogenic mechanism through upregulating tumor suppressors and autophagy by modulating canonical (Beclin-1-dependent) and non-canonical (Beclin-1-independent) signaling pathways. Additionally, there is evidence signifying that plant polyphenols target angiogenesis and metastasis in HCC via interference with multiple intracellular signals and decrease the risk against HCC. The current review offers a comprehensive understanding of how natural polyphenolic compounds exhibit their anti-HCC effects through regulation of autophagy, the non-apoptotic mode of cell death.

Current discovery strategies for hepatocellular carcinoma therapeutics

Introduction: The global incidence of hepatocellular carcinoma (HCC) is not expected to decline significantly over the next 30 years. And although the latest gene sequencing studies have established its genetic map, the potentially targetable drivers of HCC are, so far, difficult to identify. To date, only seven drugs have been approved by the FDA for unresectable HCC treatment; thus, effective therapeutic breakthroughs are still needed urgently.Areas covered: In this review, the authors discuss both genetic and epigenetic alterations in HCC and introduce the current progress with some of the representative molecular targeting inhibitors, listing some of the approved drugs for the targets of HCC. The structure-activity relationship of molecules (e.g. thalidomide, bortezomil) used for HCC is also discussed.Expert opinion: Effective therapeutic targets and effective drugs for HCC treatment are an urgent unmet need. Better understanding and characterization of genetic and epigenetic alterations, which are important to hepatocarcinogenesis, may help to understand the molecular pathogenesis of HCC, as well as provide novel therapeutic lead compounds for HCC treatment.

CRISPR/Cas9 genome-wide screening identifies KEAP1 as a sorafenib, lenvatinib, and regorafenib sensitivity gene in hepatocellular carcinoma

Sorafenib is the first-line drug used for patients with advanced hepatocellular carcinoma (HCC). However, acquired sorafenib resistance in cancer patients limits its efficacy. Here, we performed the first genome-wide CRISPR/Cas9-based screening on sorafenib-treated HCC cells to identify essential genes for non-mutational mechanisms related to acquired sorafenib resistance and/or sensitivity in HCC cells. KEAP1 was identified as the top candidate gene by Model-based Analysis of Genome-wide CRISPR/Cas9 Knockout (MAGeCK). KEAP1 disrupted HCC cells were less sensitive than wild-type cells in short- and long-term sorafenib treatments. Compared to wild-type cells, KEAP1-disrupted cells showed lower basal and sorafenib-induced reactive oxygen species (ROS) levels and were more resistant to oxidative stress-induced cell death. The absence of KEAP1 led to increased activity of Nrf2, a key transcription factor controlling antioxidant responses, as further evidenced by increased expression of Nrf2-controlled genes including NQO1, GPX2 and TXNRD1, which were positively associated with chemoresistance. In addition, KEAP1 disruption counteracted the reduction of cell viability and the elevation of ROS caused by lenvatinib, a drug that recently showed clinical efficacy as a first-line treatment for unresectable HCC. Finally, Keap1 disruption also increased the resistance of cells to regorafenib, a recently approved drug to treat HCC as a second line therapy. Taken together, our data indicate that deregulation of the KEAP1/Nrf2 pathway following KEAP1 inactivation contributes to sorafenib, lenvatinib, and regorafenib resistance in human HCC cells through up-regulation of Nrf2 downstream genes and decreased ROS levels.

Rotundic Acid Induces DNA Damage and Cell Death in Hepatocellular Carcinoma Through AKT/mTOR and MAPK Pathways

Hepatocellular carcinoma (HCC) is the fourth largest cause of cancer-related deaths worldwide with limited therapeutic interventions. Renewed interest in natural products as drug leads has resulted in a paradigm shift toward the rapid screening of medicinal plants for the discovery of new chemical entities. Rotundic acid (RA), a plant-derived triterpenoid, has been anecdotally reported to possess anti-inflammatory and cardio-protective abilities. The present study highlights the anti-cancer efficacy of RA on HCC in vitro and in vivo. The inhibitory effects of RA on HCC cell viability was determined by MTT. Soft agar colony formation and clonogenic assays also showed that RA inhibited HCC cell proliferation. Flow cytometry, confocal, and western blot results further indicated that RA induced cell cycle arrest, DNA damage, and apoptosis by modulating the AKT/mTOR and MAPK pathways. Besides the suppression of migration and invasion, tube formation and VEGF-ELISA revealed the anti-angiogenic abilities of RA on HCC. Moreover, RA also inhibited tumor growth in a HepG2 xenograft mouse model. To our best knowledge, this is the first extensive study of the anticancer activity of RA on HCC. The results demonstrate that RA could be a potential drug candidate for HCC treatment.

Interaction Between Sex and Organic Anion-Transporting Polypeptide 1b2 on the Pharmacokinetics of Regorafenib and Its Metabolites Regorafenib-N-Oxide and Regorafenib-Glucuronide in Mice

Regorafenib, a multikinase inhibitor used in the treatment of various solid tumors, undergoes extensive uridine 5′‐diphosphate glucuronosyltransferase (Ugt)1a9‐mediated glucuronidation to form regorafenib‐N‐β‐glucuronide (M7; RG), but the contribution of hepatic uptake transporters, such as organic anion‐transporting polypeptide (Oatp)1b2, to the pharmacokinetics of regorafenib remains poorly understood. Using NONMEM‐based, population‐based, parent‐metabolite modeling, we found that Oatp1b2 and sex strongly impact the systemic exposure to RG in mice receiving oral regorafenib. Metabolic studies revealed that the liver microsomal expression of cytochrome P450 (Cyp)3a11 is twofold lower in female mice, whereas Ugt1a9 levels and function are not sex dependent. This finding is consistent with the metabolism of regorafenib occurring via two competing pathways, and the lack of Oatp1b2 results in decreased clearance of RG. The described model provides mechanistic insights into the in vivo disposition of regorafenib.

Liver-targeted liposomes for codelivery of curcumin and combretastatin A4 phosphate: preparation, characterization, and antitumor effects

Background

Recent efforts have been focused on combining two or more therapeutic approaches with different mechanisms to enhance antitumor therapy. Moreover, nanosize drug-delivery systems for codelivering two drugs with proapoptotic and antiangiogenic activities have exhibited great potential in efficient treatment of cancers.

Methods

Glycyrrhetinic acid (GA)–modified liposomes (GA LPs) for liver-targeted codelivery of curcumin (Cur) and combretastatin A4 phosphate (CA4P) were prepared and characterized. In vitro cellular uptake, cytotoxicity, cell migration, in vivo biodistribution, antitumor activity, and histopathological studies were performed.

Results

Compared with unmodified LPs (Cur-CA4P LPs), Cur-CA4P/GA LPs were taken up effectively by human hepatocellular carcinoma cells (BEL-7402) and showed higher cytotoxicity than free drugs. In vivo real-time near-infrared fluorescence–imaging results indicated that GA-targeted LPs increased accumulation in the tumor region. Moreover, Cur-CA4P/GA LPs showed stronger inhibition of tumor proliferation than Cur, Cur + CA4P, and Cur-CA4P LPs in vivo antitumor studies, which was also verified by H&E staining.

Conclusion

GA-modified LPs can serve as a promising nanocarrier for liver-targeted co-delivery of antitumor drugs against hepatocellular carcinoma.