Profile of tivantinib and its potential in the treatment of hepatocellular carcinoma: the evidence to date

Overcoming resistance to targeted therapy using MET inhibitors in solid cancers: evidence from preclinical and clinical studies

Targeted therapy is a hallmark of cancer treatment that has changed the landscape of cancer management and enabled a personalized treatment approach. Nevertheless, the development of cancer resistance is a major challenge that is currently threatening the effective utilization of targeted therapies. The hepatocyte growth factor receptor, MET, is a receptor tyrosine kinase known for its oncogenic activity and tumorigenic potential. MET is a well-known driver of cancer resistance. A growing body of evidence revealed a major role of MET in mediating acquired resistance to several classes of targeted therapies. Deregulations of MET commonly associated with the development of cancer resistance include gene amplification, overexpression, autocrine activation, and crosstalk with other signaling pathways. Small-molecule tyrosine kinase inhibitors of MET are currently approved for the treatment of different solid cancers. This review summarizes the current evidence regarding MET-mediated cancer resistance toward targeted therapies. The molecular mechanisms associated with resistance are described along with findings from preclinical and clinical studies on using MET inhibitors to restore the anticancer activity of targeted therapies for the treatment of solid tumors.

Hepatocellular carcinoma (HCC): the most promising therapeutic targets in the preclinical arena based on tumor biology characteristics

INTRODUCTION

: Hepatocellular carcinoma (HCC) is a malignant liver tumor characterized by high molecular heterogeneity, which has hampered the development of effective targeted therapies severely. Recent experimental data have unraveled novel promising targets for HCC treatment.

AREAS COVERED

: Eligible articles were retrieved from PubMed and Web of Science databases up to July 2021. This review summarizes the established targeted therapies for advanced HCC, focusing on the strategies to overcome drug resistance and the search for combinational treatments. In addition, conventional biomarkers holding the promises for HCC treatments and novel therapeutic targets from the research field are discussed.

EXPERT OPINION

: HCC is a molecularly complex disease, with several and distinct pathways playing critical roles in different tumor subtypes. Experimental models recapitulating the features of each tumor subset would be highly beneficial to design novel and more effective therapies against this disease. Furthermore, a deeper understanding of combinatorial drug synergism and the role of the tumor microenvironment in HCC will lead to improved therapeutic outcomes.

Research Progresses of Targeted Therapy and Immunotherapy for Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is one of the most common malignant tumors worldwide, with nearly one million new cases and deaths every year. Owing to the complex pathogenesis, hidden early symptoms, rapidly developing processes, and poor prognosis, the morbidity and mortality of HCC are increasing yearly. With the progress being made in modern medicine, the treatment of HCC is no longer limited to traditional methods. Targeted therapy and immunotherapy have emerged to treat advanced and metastatic HCC in recent years. Since Sorafenib is the first molecular targeting drug against angiogenesis, targeted drugs for HCC are continually emerging. Moreover, immunotherapy plays a vital role in clinical trials. In particular, the application of immune checkpoint inhibitors, which have received increasing attention in the field of cancer treatment, is a possible research path. Interestingly, these two therapies generally complement each other at some stages of HCC, bringing new hope for patients with advanced HCC. In this paper, we discuss the research progress of targeted therapy and immunotherapy for HCC in recent years, which will provide a reference for the further development of drugs for HCC.

Targeting hepatocyte growth factor/c-mesenchymal-epithelial transition factor axis in hepatocellular carcinoma: Rationale and therapeutic strategies

Hepatocellular carcinoma (HCC) is a leading cause of cancer mortality worldwide. The outcome of current standard treatments, as well as targeted therapies in advanced stages, are still unsatisfactory. Attention has been drawn to novel strategies for better treatment efficacy. Hepatocyte growth factor/c-mesenchymal-epithelial transition factor (HGF/c-Met) axis has been known as an essential element in the regulation of liver diseases and as an oncogenic factor in HCC. In this review, we collected the evidence of HGF/c-Met as a tumor progression and prognostic marker, discussed the anti-c-Met therapy in vitro, summarized the outcome of c-Met inhibitors in clinical trials, and identified potential impetus for future anti-c-Met treatments. We also analyzed the inconsistency of HGF/c-Met from various publications and offered reasonable explanations based on the current understanding in this area. In conclusion, HGF/c-Met plays a crucial role in the progression and growth of HCC, and the strategies to inhibit this pathway may facilitate the development of new and effective treatments for HCC patients.

The Role of MET Inhibitor Therapies in the Treatment of Advanced Non-Small Cell Lung Cancer

Introduction: Non-small cell lung cancer (NSCLC) is the second most common cancer globally. The mesenchymal-epithelial transition (MET) proto-oncogene can be targeted in NSCLC patients. Methods: We performed a literature search on PubMed in December 2019 for studies on MET inhibitors and NSCLC. Phase II and III clinical trials published in English between 2014 and 2019 were selected. Results: Data on MET inhibitors (tivantinib, cabozantinib, and crizotinib) and anti-MET antibodies (emibetuzumab and onartuzumab) are reported in the text. Conclusion: Emibetuzumab could be used for NSCLC cases with high MET expression. Further, studies on onartuzumab failed to prove its efficacy, while the results of tivantinib trials were clinically but not statistically significant. Additionally, cabozantinib was effective, but adverse reactions were common, and crizotinib was generally well-tolerated.

Pharmacogenetics of the systemic treatment in advanced hepatocellular carcinoma

Hepatocellular carcinoma (HCC) accounts for the majority of primary liver cancers. To date, most patients with HCC are diagnosed at an advanced tumor stage, excluding them from potentially curative therapies (i.e., resection, liver transplantation, percutaneous ablation). Treatments with palliative intent include chemoembolization and systemic therapy. Among systemic treatments, the small-molecule multikinase inhibitor sorafenib has been the only systemic treatment available for advanced HCC over 10 years. More recently, other small-molecule multikinase inhibitors (e.g., regorafenib, lenvatinib, cabozantinib) have been approved for HCC treatment. The promising immune checkpoint inhibitors (e.g., nivolumab, pembrolizumab) are still under investigation in Europe while in the US nivolumab has already been approved by FDA in sorafenib refractory or resistant patients. Other molecules, such as the selective CDK4/6inhibitors (e.g., palbociclib, ribociclib), are in earlier stages of clinical development, and the c-MET inhibitor tivantinib did not show positive results in a phase III study. However, even if the introduction of targeted agents has led to great advances in patient response and survival with an acceptable toxicity profile, a remarkable inter-individual heterogeneity in therapy outcome persists and constitutes a significant problem in disease management. Thus, the identification of biomarkers that predict which patients will benefit from a specific intervention could significantly affect decision-making and therapy planning. Germ-line variants have been suggested to play an important role in determining outcomes of HCC systemic therapy in terms of both toxicity and treatment efficacy. Particularly, a number of studies have focused on the role of genetic polymorphisms impacting the drug metabolic pathway and membrane translocation as well as the drug mechanism of action as predictive/prognostic markers of HCC treatment. The aim of this review is to summarize and critically discuss the pharmacogenetic literature evidences, with particular attention to sorafenib and regorafenib, which have been used longer than the others in HCC treatment.

The Novel Oncolytic Compound LTX-401 Induces Antitumor Immune Responses in Experimental Hepatocellular Carcinoma

LTX-401 is a novel oncolytic compound designed for the local treatment of solid tumors. In the present study, we have examined the applicability and efficacy of LTX-401 in a rat model JM1 hepatocellular carcinoma, with particular interest in its ability to induce antitumor immunity. LTX-401 induces necrotic cell death followed by the release of immunogenic cell death mediators such as high-mobility group box 1 protein, ATP, and cytochrome c. When injected into subcutaneous and orthotopic JM1 tumors, LTX-401 treatment resulted in a strong antitumoral effect followed by complete tumor regression in the majority of animals. Additionally, LTX-401 could affect the growth of distal tumor deposits simulating metastases, hence indicating immune-mediated abscopal responses. Furthermore, LTX-401 treatment induced tumor-specific immune responses as seen by protection against tumor rechallenge and increased production of interferon-gamma (IFN-γ) by splenic cells in response to stimulation with tumor cells. Taken together, our data demonstrate that the oncolytic compound LTX-401 provides local tumor control followed by protective immune responses and may be exploited as a novel immunotherapeutic agent in hepatocellular carcinoma.

MicroRNAs as possible indicators of drug sensitivity in breast cancer cell lines

MicroRNAs (miRNAs) regulate gene expression post-transcriptionally. In this way they might influence whether a cell is sensitive or resistant to a certain drug. So far, only a limited number of relatively small scale studies comprising few cell lines and/or drugs have been performed. To obtain a broader view on miRNAs and their association with drug response, we investigated the expression levels of 411 miRNAs in relation to drug sensitivity in 36 breast cancer cell lines. For this purpose IC₅₀ values of a drug screen involving 34 drugs were associated with miRNA expression data of the same breast cancer cell lines. Since molecular subtype of the breast cancer cell lines is considered a confounding factor in drug association studies, multivariate analysis taking subtype into account was performed on significant miRNA-drug associations which retained 13 associations. These associations consisted of 11 different miRNAs and eight different drugs (among which Paclitaxel, Docetaxel and Veliparib). The taxanes, Paclitaxel and Docetaxel, were the only drugs having miRNAs in common: hsa-miR-187-5p and hsa-miR-106a-3p indicative of drug resistance while Paclitaxel sensitivity alone associated with hsa-miR-556-5p. Tivantinib was associated with hsa-let-7d-5p and hsa-miR-18a-5p for sensitivity and hsa-miR-637 for resistance. Drug sensitivity was associated with hsa-let-7a-5p for Bortezomib, hsa-miR-135a-3p for JNJ-707 and hsa-miR-185-3p for Panobinostat. Drug resistance was associated with hsa-miR-182-5p for Veliparib and hsa-miR-629-5p for Tipifarnib. Pathway analysis for significant miRNAs was performed to reveal biological roles, aiding to find a potential mechanistic link for the observed associations with drug response. By doing so hsa-miR-187-5p was linked to the cell cycle G2-M checkpoint in line with this checkpoint being the target of taxanes. In conclusion, our study shows that miRNAs could potentially serve as biomarkers for intrinsic drug resistance and that pathway analyses can provide additional information in this context.

ARQ-197 enhances the antitumor effect of sorafenib in hepatocellular carcinoma cells via decelerating its intracellular clearance

Background

Hepatocellular carcinoma (HCC) is one of the heaviest malignant burdens in China. Molecular targeting agent, sorafenib, is the main therapeutic option for antitumor therapy of advanced HCC, but it is currently too expensive for the public and its therapeutic effect does not satisfy initial expectation. Therefore, it is important to develop more effective molecular targeted therapeutic strategies for advanced HCC.

Materials and methods

The antitumor effects of sorafenib or ARQ-197, an antagonist of c-MET (tyrosine-protein kinase Met or hepatocyte growth factor receptor), were examined by MTT or in murine tumor model. The effect of ARQ-197 on epithelial-mesenchymal transition (EMT) or multidrug resistance (MDR) was examined by quantitative real-time PCR for the expression of related genes. The clearance of sorafenib in HCC cells was detected by liquid chromatography-mass spectrometry/mass spectrometry.

Results

ARQ-197 treatment enhanced the sensitivity of HCC cells to sorafenib. Mechanistic studies indicated that ARQ-197 inhibited the expression of EMT- and MDR-related genes. Moreover, ARQ-197 treatment decelerated the clearance of sorafenib in cultured HCC cells and subcutaneous HCC tumors in nude mice.

Conclusion

In the present work, our data suggested that ARQ-197 decelerated the clearance of sorafenib in HCC cells and enhanced the antitumor effect of sorafenib.

Low expression of miR-199 in hepatocellular carcinoma contributes to tumor cell hyper-proliferation by negatively suppressing XBP1

Hepatocellular carcinoma (HCC) is the third leading cause of cancer-related mortality worldwide, and microRNAs (miRs) are considered to serve important functions in the pathogenesis of HCC by regulating the expression of specific target genes. The present study was conducted to investigate the role of miR-199 and its putative target X-box binding protein 1 (XBP1) in HCC, as well as of the downstream gene cyclin D. The expression levels of miR-199, XBP1 and cyclin D were detected in clinical HCC specimens. The effect of miR-199 on the regulation of HCC cell proliferation and its underlying mechanism were examined in Hep3B2.1–7 cells, through expression assays and measurement of cell proliferation (via Cell Counting Kit-8, and 5-ethynyl-2′-deoxyuridine and DAPI double-staining assays) coupled with gain- and lose- of function experiments. The expression of XBP1 and cyclin D was significantly increased in HCC tissues when compared with adjacent non-HCC tissues, while the expression of miR-199 was decreased. Exogenous miR-199 significantly suppressed the expression of XBP1 and cyclin D in Hep3B2.1–7 cells. However, the expression of XBP1 and cyclin D significantly increased on treatment with miR-199 inhibitor. Consistently, Hep3B2.1–7 cells co-transfected with a wild type reporter plasmid [XBP1-3′untranslated region (UTR)-WT] and exogenous miR-199 exhibited lower relative luciferase enzyme activity than cells co-transfected with negative control miRNA and XBP1-3′UTR-WT, while cells co-transfected with mutated plasmid (XBP1-3′UTR-MU) and miR-199 exhibited no change. It was further observed that knockdown of XBP1 by small interfering RNA significantly decreased the expression of cyclin D in Hep3B2.1–7 cells. Additionally, exogenous miR-199 decreased the proliferation of Hep3B2.1–7 cells, which was contrary to the effect of miR-199 inhibitor. In conclusion, it was demonstrated that miR-199 negatively regulated the expression of XBP1 by directly binding to its 3′UTR and that XBP1 impacted cyclin D expression, which was associated with the cell cycle regulation in Hep3B2.1–7 cells. These findings suggested that a miR-199/XBP1/cyclin D axis may serve an important role in the pathogenesis of HCC.

Resistance a major hindrance to chemotherapy in hepatocellular carcinoma: an insight

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer mortality, accounting for almost 90% of total liver cancer burden. Surgical resection followed by adjuvant and systemic chemotherapy are the most meticulously followed treatment procedures but the complex etiology and high metastatic potential of the disease renders surgical treatment futile in majority of the cases. Another hindrance to the scenario is the acquired resistance to drugs resulting in relapse of the disease. Hence, to provide insights into development of novel therapeutic targets and diagnostic biomarkers, this review focuses on the various molecular mechanisms underlying chemoresistance in HCC. We have provided a comprehensive summary of the various strategies adopted by HCC cells, extending from apoptosis evasion, autophagy activation, drug expulsion to epigenetic transformation as modes of therapy resistance. The role of stem cells in imparting chemoresistance is also discussed. Furthermore, the review also focuses on how this knowledge might be exploited for the development of an effective, prospective therapy against HCC.

The efficacy and safety of tivantinib in the treatment of solid tumors: a systematic review and meta-analysis

BACKGROUND

Tivantinib was designed to kill cancers by targeting the mesenchymal-epithelial transition (MET) protein. Although numerous tivantinib clinical trials are ongoing, tivantinib's efficacy and safety are still not clear. This meta-analysis was done to evaluate tivantinib's efficacy and safety in solid tumor treatment.

MATERIALS AND METHODS

PUBMED, EMBASE, and other databases were searched for eligible tivantinib clinical trials. The hazard ratio (HR) and 95% confidence interval (CI) of progression-free and overall survival (PFS and OS, respectively) were pooled and analyzed to evaluate tivantinib's efficacy. Data concerning adverse events (Grade ≥ 3) were pooled to calculate relative risks (RRs) with 95% CI for tivantinib-treated compared with control arms.

FINDINGS

Patients (1824) from six randomized control trials (RCTs) were enrolled. Compared with controls, tivantinib produced a significant improvement in PFS (HR, 0.73; 95% CI 0.65-0.83) but not in OS. In the non-small-cell lung cancer (NSCLC) subgroup, tivantinib combined with erlotinib prolonged patients' PFS when compared with controls (HR, 0.75; 95% CI, 0.65-0.86). In the white population, tivantinib also significantly improve PFS between treatment and control arms (HR, 0.75; 95% CI, 0.65-0.87). Tivantinib significantly improved OS in patients with high levels of MET expression. Tivantinib was shown to increase the risk of anemia and neutropenia.

INTERPRETATION

Tivantinib was better in prolonging PFS (not OS) in patients with solid tumors. High MET expression cancers may benefit from tivantinib. Tivantinib appeared to be well-tolerated by patients.

Targeted therapy and personalized medicine in hepatocellular carcinoma: drug resistance, mechanisms, and treatment strategies

Hepatocellular carcinoma (HCC) is characterized by a growing number of new cases diagnosed each year that is nearly equal to the number of deaths from this cancer. In a majority of the cases, HCC is associated with the underlying chronic liver disease, and it is diagnosed in advanced stage of disease when curative treatment options are not applicable. Sorafenib is a treatment of choice for patients with performance status 1 or 2 and/or macrovascular invasion or extrahepatic spread, and regorafenib is the only systemic treatment found to provide survival benefit in HCC patients progressing on sorafenib treatment. Other drugs tested in different trials failed to demonstrate any benefit. Disappointing results of numerous trials testing the efficacy of various drugs indicate that HCC has low sensitivity to chemotherapy that is in great part caused by multidrug resistance. Immunotherapy for HCC is a new challenging treatment option and involves immune checkpoint inhibitors/antibody-based therapy and peptide-based vaccines. Another challenging approach is microRNA-based therapy that involves two strategies. The first aims to inhibit oncogenic miRNAs by using miRNA antagonists and the second strategy is miRNA replacement, which involves the reintroduction of a tumor-suppressor miRNA mimetic to restore a loss of function.

Precision medicine for hepatocellular carcinoma: driver mutations and targeted therapy

Hepatocellular carcinoma (HCC) is the third most frequent cause of tumor-related mortality and there are an estimated approximately 850,000 new cases annually. Most HCC patients are diagnosed at middle or advanced stage, losing the opportunity of surgery. The development of HCC is promoted by accumulated diverse genetic mutations, which confer selective growth advantages to tumor cells and are called "driver mutations". The discovery of driver mutations provides a novel precision medicine strategy for late stage HCC, called targeted therapy. In this review, we summarized currently discovered driver mutations and corresponding signaling pathways, made an overview of identification methods of driver mutations and genes, and classified targeted drugs for HCC. The knowledge of mutational landscape deepen our understanding of carcinogenesis and promise future precision medicine for HCC patients.