Treating hepatocellular carcinoma progression following first-line sorafenib: therapeutic options and clinical observations

DNMT and EZH2 inhibitors synergize to activate therapeutic targets in hepatocellular carcinoma

The development of more effective targeted therapies for hepatocellular carcinoma (HCC) patients due to its aggressiveness is urgently needed. DNA methyltransferase inhibitors (DNMTis) represented the first clinical breakthrough to target aberrant cancer epigenomes. However, their clinical efficacies are still limited, in part due to an "epigenetic switch" in which a large group of genes that are demethylated by DNMTi treatment remain silenced by polycomb repressive complex 2 (PRC2) occupancy. EZH2 is the member of PRC2 that catalyzes the placement of H3K27me3 marks. EZH2 overexpression is correlated with poor HCC patient survival. We tested the combination of a DNMTi (5-aza-2'-deoxycytidine, DAC) and the EZH2 inhibitor (EZH2i) GSK126 in human HCC cell lines on drug sensitivity, DNA methylation, nucleosome accessibility, and gene expression profiles. Compared with single agent treatments, all HCC cell lines studied showed increased sensitivity after receiving both drugs concomitant with prolonged anti-proliferative changes and sustained reactivation of nascently-silenced genes. The increased number of up-regulated genes after combination treatment correlated with prolonged anti-proliferation effects and increased nucleosome accessibility. Combination treatments also activate demethylated promoters that are repressed by PRC2 occupancy. Furthermore, 13-31% of genes down-regulated by DNA methylation in primary HCC tumors were reactivated through this combination treatment scheme in vitro. Finally, the combination treatment also exacerbates anti-tumor immune responses, while most of these genes were downregulated in over 50% of primary HCC tumors. We have linked the anti-tumor effects of DAC and GSK126 combination treatments to detailed epigenetic alterations in HCC cells, identified potential therapeutic targets and provided a rationale for treatment efficacy for HCC patients.

PDE4D binds and interacts with YAP to cooperatively promote HCC progression

The role of cAMP in the development of hepatocellular carcinoma (HCC) is controversial and the biological function of cAMP-hydrolysing enzyme phosphodiesterase 4D (PDE4D) in HCC remains unclear. In this study, we observed markedly higher PDE4D expression in HCC patients with poor survival. PDE4D bound to yes-associated protein (YAP), and PDE4D expression positively correlated with YAP expression in HCC. Overexpression of PDE4D increased YAP dephosphorylation and activity and promoted HCC cell growth in vitro and in vivo, which was attenuated by the YAP inhibitor verteporfin. In contrast, silencing PDE4D reduced YAP expression and HCC cell growth. Notably, forced expression of YAP promoted PDE4D and YAP target gene expression and cell growth, which were abrogated by the PDE4D inhibitor roflumilast. Mechanistically, silencing of YAP caused PDE4D downregulation and HCC cell apoptosis via extracellular signal-regulated kinase (ERK) activation. Roflumilast activated cAMP-PKA signaling and induced cAMP-PKA-dependent YAP phosphorylation at serine 127, resulting in YAP degradation and suppression of HCC growth, which were reversed by the PKA inhibitor PKI. Additionally, transfection of the YAP-S127A mutant reversed roflumilast-mediated suppression of YAP and cell growth. Taken together, our findings indicate that PDE4D binds to and interacts with YAP to promote HCC progression. Targeting the PDE4D-YAP interaction with roflumilast may be an effective strategy for HCC treatment.

Involvement of NF-κB/PI3K/AKT signaling pathway in the protective effect of prunetin against a diethylnitrosamine induced hepatocellular carcinogenesis in rats

Prunetin (PRU) is an O-methylated flavonoid that is present in various natural plants and a primary significant compound found in isoflavone. Liver cancer creates major carcinogenic death despite recently advanced therapies. Hepatocellular carcinoma (HCC) treatment and prognosis are better in people with secure liver function. In the present study, we evaluated the action of PRU on diethylnitrosamine (DEN) alone HCC in a rat model through inflammation-mediated cell proliferative phosphoinositide 3-kinase/protein kinase B (PI3K/AKT) pathway analysis. Male Wistar rats were divided into four groups of six rats each. Group I, normal rats; Group II, DEN alone; Group III, DEN + PRU, and Group IV, PRU-alone. All groups of rats carried out hepatic cancer development by hypothesis antioxidant, biochemical, cell proliferative, apoptosis, cytokines protein, and gene expression status profiles. In tumor incidence DEN + PRU, 100% delayed the tumor growth disappearance of the lesion,  and reversal of normal liver architecture was observed. Liver marker enzymes levels decreased when antioxidant levels (superoxidase dismutase, catalase, glutathione peroxidase, and glutathione reductase) were in Group III. Proinflammatory markers nuclear factor-κB, interleukin (IL)-6, IL-1β, and tumor necrosis factor α, were elevated in the rat's serum in Group III. Cell proliferative markers proliferating cell nuclear antigen and Cyclin-D1 protein expressions were downregulated; in contrast, Bcl-2, Bax, caspase-3, and caspase-9 gene expressions were upregulated and then it followed that protein expression of PI3K/AKT was downregulated in PRU-treated groups. PRU assisted reversal of liver damage, antioxidant enzyme restoration cytokine balance, protein, and gene expression to control levels. Taken together, PRU improves functions of the liver, and as such prevents HCC. PRU can be used together with chemopreventives for HCC.

MCCC2 promotes HCC development by supporting leucine oncogenic function

Background

The role of methylcrotonoyl-CoA carboxylase 2 (MCCC2) in the development of tumors is well-established, and the involvement of leucine in the liver is well-known. However, the role of MCCC2 and the correlation between MCCC2 and leucine in the progression of hepatocellular carcinoma (HCC) have not yet been reported.

Methods

In this study, the Gepia database was used to evaluate the prognostic value of MCCC2 in HCC. The expression and localization of MCCC2 in HCC cells were determined by western blot and immunofluorescence assays. Flow cytometry and CCK-8 and transwell assays were carried out to explore the effect of MCCC2 on cell proliferation, migration, and invasion. In addition, mass spectrometry analysis was used to predict the potential cell function of MCCC2 in HCC.

Results

We found that the expression of MCCC2 increased in HCC tissues and that high expression of MCCC2 could predict poor outcomes in HCC patients. Knockdown expression of MCCC2 in HCC cells could reduce cell proliferation, migration, and invasion ability in vitro and could inhibit HCC cell proliferation in vivo. Interestingly, we found that HCC cells transfected with MCCC2-sgRNA failed to respond to leucine deprivation. Meanwhile, leucine deprivation inhibited cell proliferation, migration, and invasion in HCC cells where MCCC2 was present rather than in cells where MCCC2 was absent. In addition, knockdown of MCCC2 significantly reduced the glycolysis markers, glucose consumption, lactate secretion, and acetyl-CoA level, which is a product of leucine metabolism. Furthermore, we found that MCCC2 promotes the activation of ERK. Profiling the MCCC2 binding proteins revealed that MCCC2-associated proteins are enriched in biological processes, such as protein metabolism, energy pathway, and metabolism in HCC cells.

Conclusions

Our findings revealed that MCCC2 plays a critical role in the development of HCC, and the leucine metabolism pathway might be a novel target in HCC treatment.

Enhancer of zeste 2 polycomb repressive complex 2 subunit promotes sorafenib resistance of hepatocellular carcinoma though insulin-like growth factor 1 receptor

Enhancer of zeste 2 polycomb repressive complex 2 subunit (EZH2) is the core component of polycomb repressive complex 2 and is overexpressed in several types of solid malignancies. It has been reported that EZH2 contributes to sorafenib resistance of hepatocellular carcinoma (HCC). However, its underlying molecular mechanisms remain unknown. In this study, we demonstrated that EZH2 induced sorafenib resistance of HCC cells in vitro. Mechanistically, EZH2 was a potent regulator of insulin-like growth factor 1 receptor (IGF1R) and EZH2-modulated IGF1R expression by directly transcriptionally repressing a set of microRNAs (miRNAs) including miR-101, miR-122, miR-125b, and miR-139. These miRNAs were required for EZH2-mediated sorafenib resistance by promoting IGF1R expression. Surprisingly, IGF1R inhibitors significantly reversed EZH2-induced sorafenib resistance. Collectively, we proposed a novel model for an EZH2 - miRNAs - IGF1R regulatory axis, which might provide insights into how EZH2 contributes to sorafenib resistance in HCC.

USP10 Promotes Proliferation of Hepatocellular Carcinoma by Deubiquitinating and Stabilizing YAP/TAZ

Yes-associated protein (YAP) and its paralog, transcriptional coactivator with PDZ-binding motif (TAZ), play pivotal roles in promoting the progression of hepatocellular carcinoma. However, the regulatory mechanism underpinning aberrant activation of YAP/TAZ in hepatocellular carcinoma remains unclear. In this study, we globally profiled the contribution of deubiquitinating enzymes (DUB) to both transcriptional activity and protein abundance of YAP/TAZ in hepatocellular carcinoma models and identified ubiquitin-specific peptidase 10 (USP10) as a potent YAP/TAZ-activating DUB. Mechanistically, USP10 directly interacted with and stabilized YAP/TAZ by reverting their proteolytic ubiquitination. Depletion of USP10 enhanced polyubiquitination of YAP/TAZ, promoted their proteasomal degradation, and ultimately arrested the proliferation of hepatocellular carcinoma in vitro and in vivo. Expression levels of USP10 positively correlated with the abundance of YAP/TAZ in hepatocellular carcinoma patient samples as well as in N-nitrosodiethylamine (DEN)-induced liver cancer mice models. Collectively, this study establishes the causal link between USP10 and hyperactivated YAP/TAZ in hepatocellular carcinoma cells and provides a rationale for potential therapeutic interventions in the treatment of patients with hepatocellular carcinoma harboring a high level of YAP/TAZ. SIGNIFICANCE: These findings identify USP10 as a DUB of YAP/TAZ and its role in hepatocellular carcinoma progression, which may serve as a potential therapeutic target for hepatocellular carcinoma treatment.

7-Methoxy-1-Tetralone Induces Apoptosis, Suppresses Cell Proliferation and Migration in Hepatocellular Carcinoma via Regulating c-Met, p-AKT, NF-κB, MMP2, and MMP9 Expression

This study aimed to determine the anti-proliferative and anti-migratory effects of 7-methoxy-1-tetralone (MT) in hepatocellular carcinoma (HCC) cells. MTT assay assessed HCC cell viability; cell apoptosis of HCC cells was determined by flow cytometry; wound healing assay evaluated HCC cell migratory ability; protein expression levels were assessed using western blot assay; the in vivo antitumor effects of MT were tested in BALB/c nude mice and the pathological changes within the tumor tissues were evaluated by immunohistochemistry. MT treatment significantly suppressed the cell proliferative and migratory potentials of HepG2 cells, and induced HepG2 cell apoptosis. The western blot assay showed that MT treatment caused a suppression on c-Met, phosphorylated AKT (p-AKT), NF-κB, matrix metallopeptidase 2 (MMP2)/MMP9 protein levels in HepG2 cells. Further in vivo animal studies deciphered that MT treatment suppressed tumor growth of HepG2 cells in the nude mice, but had no effect on the body weight and the organ index of liver and spleen. Further immunohistochemistry analysis of the dissected tumor tissues showed that MT treatment significantly suppressed the protein expression levels of NF-κB, MMP9, MMP2, and p-AKT. In summary, the present study demonstrated the anti-tumor effects of MT on the HCC, and MT suppressed HCC progression possibly via regulating proliferation- and migration-related mediators including c-Met, p-AKT, NF-κB, MMP2, and MMP9 in HepG2 cells.

High expression of RAB38 promotes malignant progression of pancreatic cancer

Ras-Related Protein Rab-38 (RAB38), which belongs to the RAB family, is involved in the biogenesis of lysosome-related organelles and defense against certain microbial infections. However, the clinical significance and potential function of RAB38 in pancreatic adenocarcinoma remain unclear. In the present study, an immunohistochemical assay was performed to analyze the expression of RAB38 in pancreatic adenocarcinoma tumor specimens from 82 patients, and the clinicopathological characteristics and survival rate of these patients were further examined. To validate the role of RAB38 in tumors, the effect of RAB38 on tumor cell proliferation, migration and invasion was assessed by establishing RAB38 knockdown cell lines. Reverse transcription-quantitative polymerase chain reaction and western blotting were used to examine the expression levels of proteins associated with the cancer cell behavior. In addition, the inhibitory effect of RAB38 silencing on pancreatic cancer was examined in mice. The immunohistochemistry results revealed that RAB38 was upregulated and positively correlated with the grade of progression in pancreatic adenocarcinoma patients. Further investigation indicated that RAB38 downregulation significantly suppressed the proliferation, migration and invasive capacity of pancreatic cancer cells, as well as decreased the expression levels of Ki67, proliferating cell nuclear antigen, and matrix metalloproteinases 2 and 9. RAB38 silencing also inhibited the development of pancreatic cancer in vivo. Taken together, a high level of RAB38 was significantly associated with the malignant phenotypes of pancreatic cancer, suggesting that RAB38 may serve as a novel biomarker and a potential therapeutic target for pancreatic cancer.

Integrative Epigenetic Analysis Reveals Therapeutic Targets to the DNA Methyltransferase Inhibitor Guadecitabine (SGI-110) in Hepatocellular Carcinoma

There is an urgent need to develop more effective therapies for hepatocellular carcinoma (HCC) because of its aggressiveness. Guadecitabine (SGI-110) is a second-generation DNA methyltransferase inhibitor (DNMTi), which is currently in clinical trials for HCC and shows greater stability and performance over first-generation DNMTis. In order to identify potential therapeutic targets of SGI-110 for clinical trials, HCC cell lines (SNU398, HepG2, and SNU475) were used to evaluate the effects of transient SGI-110 treatment by an integrative analysis of DNA methylation, nucleosome accessibility, gene expression profiles, and its clinical relevance by comparison to The Cancer Genome Atlas (TCGA) HCC clinical data. Each HCC cell line represents a different DNA methylation subtype of primary HCC tumors based on TCGA data. After SGI-110 treatment, all cell lines were sensitive to SGI-110 with prolonged antiproliferation effects. Expression of up-regulated genes, including tumor suppressors, was positively correlated with nucleosome accessibility and negatively correlated with gene promoter DNA methylation. Alternatively, expression of down-regulated genes, such as oncogenes, was negatively correlated with nucleosome accessibility and positively correlated with gene body DNA methylation. SGI-110 can also act as a dual inhibitor to down-regulate polycomb repressive complex 2 (PRC2) genes by demethylating their gene bodies, resulting in reactivation of PRC2 repressed genes without involvement of DNA methylation. Furthermore, it can up-regulate endogenous retroviruses to reactivate immune pathways. Finally, about 48% of frequently altered genes in primary HCC tumors can be reversed by SGI-110 treatment.

CONCLUSION

Our integrative analysis has successfully linked the antitumor effects of SGI-110 to detailed epigenetic alterations in HCC cells, identified potential therapeutic targets, and provided a rationale for combination treatments of SGI-110 with immune checkpoint therapies.

Sorafenib response in hepatocellular carcinoma: MicroRNAs as tuning forks

Hepatocellular carcinoma (HCC) is the primary liver malignancy that contributes towards the second most common cause of cancer-related mortality. The targeted chemotherapeutic agent, sorafenib, is known to show a statistically significant but limited overall survival advantage in advanced HCC. However, the individual patient response towards sorafenib varies drastically, with most experiencing stable disease and few with partial response; complete response is very rare. Progressive disease despite the treatment is also evident in many patients, indicating drug resistance. These varied responses have been linked with the modulation of several intracellular signaling pathways. Notably, the regulation of these pathways through diverse operating biomolecules, including microRNAs (miRNAs), is the focus of recent studies. MicroRNAs are tiny, non-coding RNA molecules that regulate the expression of several target genes. In addition, miRNAs are known to play a role in the progression of HCC carcinogenesis. Interestingly, miRNAs have also been identified to play differential roles in terms of sorafenib response in HCC such as biomarkers and functional modulation of cellular response to sorafenib, hence, they are also being therapeutically evaluated. This review outlines the role of reported miRNAs in different aspects of sorafenib response in HCC.

Prediction of Response to Sorafenib in Hepatocellular Carcinoma: A Putative Marker Panel by Multiple Reaction Monitoring-Mass Spectrometry (MRM-MS)

Sorafenib is the only standard treatment for unresectable hepatocellular carcinoma (HCC), but it provides modest survival benefits over placebo, necessitating predictive biomarkers of the response to sorafenib. Serum samples were obtained from 115 consecutive patients with HCC before sorafenib treatment and analyzed by multiple reaction monitoring-mass spectrometry (MRM-MS) and ELISA to quantify candidate biomarkers. We verified a triple-marker panel to be predictive of the response to sorafenib by MRM-MS, comprising CD5 antigen-like (CD5L), immunoglobulin J (IGJ), and galectin-3-binding protein (LGALS3BP), in HCC patients. This panel was a significant predictor (AUROC > 0.950) of the response to sorafenib treatment, having the best cut-off value (0.4) by multivariate analysis. In the training set, patients who exceeded this cut-off value had significantly better overall survival (median, 21.4 months) than those with lower values (median, 8.6 months; p = 0.001). Further, a value that was lower than this cutoff was an independent predictor of poor overall survival [hazard ratio (HR), 2.728; 95% confidence interval (CI), 1.312-5.672; p = 0.007] and remained an independent predictive factor of rapid progression (HR, 2.631; 95% CI, 1.448-4.780; p = 0.002). When applied to the independent validation set, levels of the cut-off value for triple-marker panel maintained their prognostic value for poor clinical outcomes. On the contrast, the triple-marker panel was not a prognostic factor for patients who were treated with transarterial chemoembolization (TACE). The discriminatory signature of a triple-marker panel provides new insights into targeted proteomic biomarkers for individualized sorafenib therapy.

The c-Met receptor: Implication for targeted therapies in colorectal cancer

c-Met (mesenchymal–epithelial transition factor) is a tyrosine kinase receptor activated by hepatocyte growth factor and regulates multiple biological processes, such as cell scattering, survival, and proliferation. Aberrant c-Met signaling has been implicated in a variety of cancer types, including colorectal cancer. c-Met is genetically altered through various mechanisms that is associated with colorectal cancer progression and metastasis. Especially, in colorectal cancer, preclinical evidence for the aberrant activation of the c-Met signaling exists. Accordingly, molecular targeting of c-Met receptor could be a promising strategy, in the treatment of colorectal cancer patients. Recently, it was also shown that crosstalk between c-Met and other cell surface receptors attributes to tumorigenesis and development of therapeutic resistance. Characterization of the molecular mechanisms through which c-Met crosstalks with other receptors in favor of tumor formation and progression remains to explore. This review will describe the mechanisms of aberrant c-Met signaling in colorectal cancer and discuss on additional roles for c-Met receptor through crosstalk with other tyrosine kinase receptors and cell surface proteins in colorectal cancer. Novel therapeutic approaches for c-Met pathway targeting will also be discussed.

The albumin-bilirubin grade improves hepatic reserve estimation post-sorafenib failure: implications for drug development

BACKGROUND

Drug development in hepatocellular carcinoma (HCC) is limited by disease heterogeneity, with hepatic reserve being a major source of variation in survival outcomes. The albumin-bilirubin (ALBI) grade is a validated index of liver function in patients with HCC.

AIM

To test the accuracy of the ALBI grade in predicting post-sorafenib overall survival (PSOS) in patients who permanently discontinued treatment.

METHODS

From a prospectively maintained international database of 447 consecutive referrals, we derived 386 eligible patients treated with sorafenib within Barcelona Clinic Liver Cancer C stage (62%), 75% of whom were of Child class A at initiation. Clinical variables at sorafenib discontinuation were analysed for their impact on post-sorafenib overall survival using uni- and multivariable analyses.

RESULTS

Median post-sorafenib overall survival of the 386 eligible patients was 3.4 months and median sorafenib duration was 2.9 months, with commonest causes of cessation being disease progression (68%) and toxicity (24%). At discontinuation, 92 patients (24%) progressed to terminal stage, due to worsening Child class to C in 40 (10%). Median post-sorafenib overall survival in patients eligible for second-line therapies (n = 294) was 17.5, 7.5 and 1.9 months according respectively to ALBI grade 1, 2 and 3 (P < 0.001).

CONCLUSIONS

The ALBI grade at sorafenib discontinuation identifies a subset of patients with prolonged stability of hepatic reserve and superior survival. This may allow improved patient selection for second-line therapies in advanced HCC.

The dual targeting of insulin and insulin-like growth factor 1 receptor enhances the mTOR inhibitor-mediated antitumor efficacy in hepatocellular carcinoma

Deregulation of mTOR and IGF pathways is frequent in hepatocellular carcinoma (HCC), thus mTOR and IGF1R represent suitable therapeutic targets in HCC. The aim of this study was to evaluate the effects of mTOR inhibitors (mTORi) and OSI-906, blocker of IGF1R/IR, on HCC cell proliferation, viability, migration and invasion, and alpha-fetoprotein (α-FP) secretion. In HepG2 and HuH-7 we evaluated, the expression of mTOR and IGF pathway components; the effects of Sirolimus, Everolimus, Temsirolimus and OSI-906 on cell proliferation; the effects of Sirolimus, OSI-906, and their combination, on cell secretion, proliferation, viability, cell cycle, apoptosis, invasion and migration. Moreover, intracellular mechanisms underlying these cell functions were evaluated in both cell lines. Our results show that HepG2 and HuH-7 present with the same mRNA expression profile with high levels of IGF2. OSI-906 inhibited cell proliferation at high concentration, while mTORi suppressed cell proliferation in a dose-time dependent manner in both cell lines. The co-treatment showed an additive inhibitory effect on cell proliferation and viability. This effect was not related to induction of apoptosis, but to G0/G1 phase block. Moreover, the co-treatment prevented the Sirolimus-induced AKT activation as escape mechanism. Both agents demonstrated to be differently effective in inhibiting α-FP secretion. Sirolimus, OSI-906, and their combination, blocked cell migration and invasion in HuH-7. These findings indicate that, co-targeting of IGF1R/IR and mTOR pathways could be a novel therapeutic approach in the management of HCC, in order to maximize antitumoral effect and to prevent the early development of resistance mechanisms.

In Vitro and In Vivo Anticancer Activity of Gimatecan against Hepatocellular Carcinoma

Objective: Gimatecan is a new camptothecin (CPT) analogue that inhibits tumor growth by targeting DNA topoisomerase I (TOP I) and introducing strong and persistent DNA cleavage. Anti-tumor activity has been demonstrated with a wide range of solid tumors in previous preclinical and clinical studies. Here, we investigated for the first time the effects of gimatecan on the proliferation of hepatocellular carcinoma (HCC) cells both in vitro and in vivo. Methods: Anticancer efficacy of gimatecan were evaluated in a panel of HCC cell lines and corresponding mouse xenograft models. Inhibition of cell proliferation was measured by CellTiter-Glo cell viability assay. In vivo, gimatecan and control preparations were orally administered every four days, for a total of four times. Tumor volume and body weights of the mice were measured twice weekly. Results: In vitro cytotoxicity evaluation showed that gimatecan inhibited the proliferation of a large panel of HCC cell lines in a dose dependent manner, with IC50 values ranging between 12.1~1085.0 nM. In vivo evaluation in mouse xenograft models showed significant antitumor effects of gimatecan at 0.8mg/kg and 0.4mg/kg as compared to the control group. Conclusion: This study suggested that gimatecan may have the potential to be used as a chemotherapeutic agent for the treatment of HCC.

Hepatocellular Carcinoma Treatment With Sorafenib: Real-Life Evaluation of Prognostic Factors and a Practical Clue for Patient Management

Introduction

Sorafenib chemotherapy is the first-line therapy for patients with hepatocellular carcinoma (HCC) in an advanced stage. The aim of this study was to evaluate prognostic factors of survival in HCC patients treated with sorafenib, in real-life clinical practice.

Material and methods

Retrospective study of HCC patients who initiated treatment with sorafenib, following assessment and indication from the multidisciplinary group.

Results

There were included 36 patients, mostly male (89%) and with a mean age of 65 years. The main etiologies were chronic hepatitis C (44%) and alcoholic liver disease (36%). Twenty patients (56%) were classified as Child–Pugh A and 16 patients (44%) as Child–Pugh B. Half of the patients group were staged as BCLC C and the remaining as BCLC B. Significant adverse events were observed in 15 patients (42%) and were associated with longer survival (21.5 vs. 3.2 months, p < 0.001). The most frequent adverse events were diarrhea and palmar-plantar syndrome. Median survival was 17.3 months for Child–Pugh A versus 3.2 months for Child–Pugh B patients (p = 0.001). Within Child–Pugh A, median OS was 21.5 months for BCLC B patients and 15.7 months for BCLC C patients (p = 0.001).

Discussion and conclusions

The main prognostic factors beyond Child–Pugh class and BCLC stage included the occurrence of significant adverse events. Being related to increased time of exposure to the drug, it points out the need of dose reducing instead of discontinuation whenever significant adverse events occur.

Manipulating Angiogenesis by Targeting Endothelial Metabolism: Hitting the Engine Rather than the Drivers-A New Perspective?

Excessive angiogenesis (i.e., the formation of new blood vessels) contributes to different pathologies, among them cancer and ocular disorders. Conversely, dysfunction of endothelial cells (ECs) contributes to cardiovascular complications, as is the case in diabetes. Inhibition of pathologic angiogenesis in blinding eye disease and cancer by targeting growth factors such as vascular endothelial growth factor has become an accepted therapeutic strategy. However, recent studies also unveiled the emerging importance of EC metabolism in controlling angiogenesis. In this overview, we will discuss recent insights in the metabolic regulation of angiogenesis, focusing on the best-characterized metabolic pathways, and highlight deregulation of EC metabolism in cancer and diabetes. We will give an outlook on how targeting EC metabolism can be used for blocking pathologic angiogenesis and for normalizing EC dysfunction.

Elevated hepatocyte growth factor expression as an autocrine c-Met activation mechanism in acquired resistance to sorafenib in hepatocellular carcinoma cells

Hepatocellular carcinoma (HCC) is the most common type of primary liver cancer and the third leading cause of cancer‐related deaths worldwide. Limitations in HCC treatment result due to poor prognosis and resistance against traditional radiotherapy and chemotherapies. The multikinase inhibitor sorafenib is the only FDA approved drug available for advanced HCC patients, and development of second‐line treatment options for patients who cannot tolerate or develop resistance to sorafenib is an urgent medical need. In this study, we established sorafenib‐resistant cells from Huh7 and Mahlavu cell lines by long‐term sorafenib exposure. Sorafenib‐resistant HCC cells acquired spindle‐shape morphology, upregulated mesenchymal markers, and showed significant increase in both migration and invasion abilities compared to their parental counterparts. Moreover, after long‐term sorafenib treatment, HCC cells showed induction of hepatocyte growth factor (HGF) synthesis and secretion along with increased levels of c‐Met kinase and its active phosphorylated form, indicating autocrine activation of HGF/c‐Met signaling. Importantly, the combined treatment of the resistant cells with c‐Met kinase inhibitor SU11274 and HGF neutralizing antibody significantly reversed the increased invasion ability of the cells. The combined treatment also significantly augmented sorafenib‐induced apoptosis, suggesting restoration of sorafenib sensitivity. These results describe, for the first time, compensatory upregulation of HGF synthesis leading to autocrine activation of HGF/c‐Met signaling as a novel cellular strategy in the acquisition of sorafenib resistance. Therefore, we suggest that combinatorial therapeutic strategies with HGF and c‐Met inhibitors comprise promising candidates for overcoming sorafenib resistance.

Targeting c-Met in Cancer by MicroRNAs: Potential Therapeutic Applications in Hepatocellular Carcinoma

Preclinical Research Cancer is one of the world's deadliest diseases, with very low survival rates and increased occurrence in the future. Successfully developed target-based therapies have significantly changed cancer treatment. However, primary and/or acquired resistance in the tumor is a major challenge in current therapies and novel combinational therapies are required. RNA interference-mediated gene inactivation, alone or in combination with other current therapies, provides novel promising therapeutics that can improve cure rate and overcome resistance mechanisms to conventional therapeutics. Hepatocyte Growth Factor/c-Met signaling is one of the most frequently dysregulated pathways in human cancers and abnormal c-Met activation is correlated with poor clinical outcomes and drug resistance in hepatocellular carcinoma (HCC). In recent years, a growing number of studies have identified several inhibitors and microRNAs (miRNAs), specifically targeting c-Met in various cancers, including HCC. In this review, we discuss current knowledge regarding miRNAs, focusing on their involvement in cancer and their potential as research tools and therapeutics. Then, we focus on the potential use of c-Met targeting miRNAs for suppressing aberrant c-Met signaling in HCC treatment.

Refining sorafenib therapy: lessons from clinical practice

Understanding the best use of sorafenib is essential in order to maximize clinical benefit in hepatocellular carcinoma. Based on Phase III and noninterventional study data, as well as our extensive experience, we discuss dose modification in order to manage adverse events, disease response evaluation and how to maximize treatment benefit. Sorafenib should be initiated at the approved dose (400 mg twice daily) and reduced/interrupted as appropriate in order to manage adverse events. Dose modification should be considered before discontinuation. Appropriate tumor response assessment is critical. Focusing on radiologic response may result in premature sorafenib discontinuation; symptomatic progression should also be considered. If second-line therapies or trials are unavailable, continuing sorafenib beyond radiologic progression may provide a clinical benefit. Our recommendations enable the maximization of treatment duration, and hence clinical benefit, for patients.

HCC therapies--lessons learned

The antiangiogenic multikinase inhibitor sorafenib was the first systemic agent to demonstrate a significant improvement in the overall survival of patients with advanced hepatocellular carcinoma (HCC), thereby introducing molecularly-targeted therapy in a therapeutic field of unmet needs. However, survival benefits for patients on sorafenib treatment are modest in clinical practice and advancing the field is far more challenging than initially anticipated. Molecular and clinical heterogeneity diminishes signals of potential activity in unselected populations, and underlying liver cirrhosis seals the fate of many novel targeted agents by causing relevant toxicity and mortality. The failure of subsequent randomized controlled phase III trials underscores the urgent need to identify the driver targets and to develop matched active agents with manageable toxicities in specific phase I studies in patients with cirrhosis. Refinement of phase II-III trial designs with a biomarker-enriched patient-selection process and stratification according to prognostic baseline factors is indispensable to prevent another 5-year vain endeavour in systemic therapy of HCC.