RAF-targeted therapy for hepatocellular carcinoma in the regenerating liver

Protomer selectivity of type II RAF inhibitors within the RAS/RAF complex

RAF dimer inhibitors offer therapeutic potential in RAF- and RAS-driven cancers. The utility of such drugs is predicated on their capacity to occupy both RAF protomers in the RAS-RAF signaling complex. Here we describe a method to conditionally quantify drug-target occupancy at selected RAF protomers within an active RAS-RAF complex in cells. RAF target engagement can be measured in the presence or absence of any mutant KRAS allele, enabling the high-affinity state of RAF dimer inhibitors to be quantified in the cellular milieu. The intracellular protomer selectivity of clinical-stage type II RAF inhibitors revealed that ARAF protomer engagement, but not engagement of BRAF or CRAF, is commensurate with inhibition of MAPK signaling in various mutant RAS cell lines. Our results support a fundamental role for ARAF in mutant RAS signaling and reveal poor ARAF protomer vulnerability for a cohort of RAF inhibitors undergoing clinical evaluation.

Simulated model of RAPID concept: highlighting innate inflammation and liver regeneration

Background

The resection and partial liver segment II/III transplantation with delayed total hepatectomy (RAPID) concept is a novel transplantation technique for removal of non‐resectable liver tumours. The aim of this study was to establish a simulated RAPID model to explore the mechanism involved in the liver regeneration.

Methods

A RAPID model was created in rats involving cold ischaemia and reperfusion of the selected future liver remnant (FLR), portal vein ligation, followed by resection of the deportalized lobes in a second step. Histology, liver regeneration and inflammatory markers in RAPID‐treated rats were compared with those in controls that underwent 70 per cent hepatectomy with the same FLR size. The effects of interleukin (IL) 6 and macrophage polarization on hepatocyte viability were evaluated in an in vitro co‐culture system of macrophages and BRL hepatocytes.

Results

The survival rate in RAPID and control hepatectomy groups was 100 per cent. The regeneration rate was higher in the RAPID‐treated rats, with higher levels of IL‐6 and M1 macrophage polarization (P < 0·050). BRL hepatocytes co‐cultured with M1 macrophages showed a higher proliferation rate through activation of the IL‐6/signal transducer and activator of transcription 3/extracellular signal‐regulated kinase pathway. This enhancement of proliferation was inhibited by tocilizumab or gadolinium trichloride (P < 0·050).

Conclusion

The surgical model provides a simulation of RAPID that can be used to study the liver regeneration profile.

Efficacy evaluation of the combination therapy of sorafenib and transarterial chemoembolization for unresectable HCC: a systematic review and meta-analysis of comparative studies

Background

Sorafenib and transarterial chemoembolization (TACE) are the standard treatments recommended by guidelines for unresectable hepatocellular carcinoma (HCC). Although previous studies have shown the combination therapy of sorafenib and TACE to be safe, there is no consensus regarding its efficacy. This systematic review and meta-analysis, which was based on the findings of comparative clinical trials, was conducted to provide up-to-date and comprehensive information about the efficacy of combination therapy versus TACE monotherapy in unresectable HCC.

Methods

Multiple databases were systematically reviewed to screen studies through particular inclusion criteria. Hazard ratio (HR) with 95% confidence intervals (95% CIs) was collected and analyzed by Revman 5.3 in a fixed or random effects meta-analysis model. Adverse events (AEs) were also evaluated.

Results

This review ultimately included 14 comparative studies focused on combination therapy versus TACE monotherapy. Of these: 5 studies conducted TACE plus sorafenib versus TACE with placebo; 9 studies provided overall survival (OS) in combination groups which ranged from 10.3 to 29.7 months; and 10 studies provided time to progression (TTP) in combination groups which ranged from 2.6 to 10.8 months. The disease control rate (DCR) in combination groups ranged from 9.7% to 89.2% in 7 of the studies. After performing a random effects meta-analysis model, our study showed that OS (HR =0.65, 95% CI: 0.54-0.79, P<0.0001) and TTP (HR =0.72, 95% CI: 0.59-0.88, P=0.001) have been significantly improved in the combination therapy group when compared with the TACE monotherapy group. AEs mainly included hand-foot skin reaction (HFSR), fatigue and diarrhea and the majority of these were in grade 1 or grade 2.

Conclusions

Combination therapy has significant advantages over TACE monotherapy in terms of improving TTP and OS.

As Clinical Markers, Hand-Foot-Skin Reaction and Diarrhea Can Predict Better Outcomes for Hepatocellular Carcinoma Patients Receiving Transarterial Chemoembolization plus Sorafenib

BACKGROUND

Combination therapy of transarterial chemoembolization plus sorafenib (TACE-S) has been proven to be safe and effective for hepatocellular carcinoma (HCC); however, this combination therapy is associated with a high incidence of adverse events (AEs). Our study focused on the relationships between AEs and treatment outcomes and aimed to discover AE-based clinical markers that can predict the survival benefits of combination treatment.

METHODS

From January 2010 to June 2014, a total of 235 HCC patients treated with TACE-S were retrospectively enrolled. Major sorafenib-related AEs were prospectively recorded, and their correlations with overall survival (OS) were analysed using time-dependent covariate Cox regression analyses.

RESULTS

The majority of the patients (200, 85.1%) were male, and the median age was 51 years old. After two years of follow-up, the median OS of the study population reached 12.4 months. In all, 218 patients (92.8%) presented at least one AE, and 174 (74.0%) suffered AEs ≥2 grade. Based on time-dependent multivariate analyses, the development of hand-foot skin reaction (HFSR) ≥2 grade (HR = 0.43, 95% CI: 0.32-0.58, P < 0.001) and diarrhoea ≥1 grade (HR = 0.72, 95% CI: 0.53-0.97, P=0.029) were identified as independent predictors of prolonged OS. Moreover, patients who developed both HFSR ≥2 grade and diarrhoea ≥1 grade achieved better outcomes than those patients who developed either or neither of these AEs (HR = 1.51, 95% CI: 1.11-2.06, P=0.009).

CONCLUSIONS

The development of HFSR ≥2 grade or diarrhoea ≥1 grade during TACE-S treatment indicated prolonged OS, and these AEs should be considered important clinical markers for predicting patient prognoses.

Recognition of HER2 expression in hepatocellular carcinoma and its significance in postoperative tumor recurrence

Background

The ERBB2 oncogene hypothesis is challenged in hepatocellular carcinoma (HCC) with the conflicting evidences of human epidermal growth factor receptor 2 (HER2) overexpression. HER2 could be a new target as a treatment option for HCC as well as tumor recurrence after surgery. HER2 in HCC biology needs further explorations.

Methods

Clinical and mRNA data of HCC patients were obtained from TCGA HCC cohort, GSE89377 and GSE115018. Western Blotting and immunohistochemistry were employed to test expression of HER2, E‐cadherin, and Vimentin. In HepG2, JM1, HER2‐transfected McA cells, and TGF‐β cocultured JM1 cells, HCC biology, including cell survival, proliferation, and epithelial‐to‐mesenchymal transition (EMT) phenotypes were evaluated.

Results

ERBB2 mRNA amplification was found in HCC datasets, and its expression was downregulated in high grade HCC with a worse overall survival. HER2 overexpression was identified in H4IIE, HepG2, JM1 cells, and 82% (14/17) HCC samples, and tumor stage was correlated with expression of HER2, E‐cadherin, and Vimentin (P < 0.05). Trastuzumab with the high concentrations suppressed proliferation of HER2‐positive hepatoma cells (P < 0.05); in the coculture model to induce EMT of JM1 cells, HER2 expression increased with downregulated E‐cadherin and upregulated Vimentin. Trastuzumab intravenous injection inhibited in vivo tumor size and metastases (P < 0.05). Signal analysis revealed that HER2 functioned through upregulation of β‐catenin and inhibition of SMAD3.

Conclusion

HER2 expression pattern is linked with tumor stage and overall survival; the transforming function of HER2 is found more relevant through β‐catenin and SMAD3. HER2‐targeted treatment is recommended to suppress the HER2‐mediated tumor growth during postoperative liver regeneration.

Liver regeneration microenvironment in liver cancer: Research progress and prospect

The proposal of the new concept of liver regeneration microenvironment in liver cancer (LC) contributes to the overall understanding of how LC microenvironment influences the occurrence and development of LC through liver regeneration microenvironment, inflammatory microenvironment, immune microenvironment, and angiogenesis microenvironment, and helps explore more comprehensive and effective preventive and therapeutic measures for LC to improve the capability of LC prevention and cure. On the basis of eliminating hepatocellular carcinoma cells or tissues, the maintenance of normal liver regeneration and improvement of liver regeneration microenvironment in LC is an important strategy for LC prevention and treatment. Improving liver regeneration microenvironment to prevent or reverse the occurrence, development, and metastasis of LC should be an important research direction of LC prevention and treatment research. In recent years, traditional Chinese medicine research and application have made some progress in improving liver regeneration microenvironment to prevent or reverse the occurrence, development, recurrence, and metastasis of LC. However, it remains to be solved on how to accurately reveal the comprehensive network mechanism and how to provide advanced evidence-based medical evidence, which needs further extensive research.

Liver regeneration microenvironment of hepatocellular carcinoma for prevention and therapy

Research on liver cancer prevention and treatment has mainly focused on the liver cancer cells themselves. Currently, liver cancers are no longer viewed as only collections of genetically altered cells but as aberrant organs with a plastic stroma, matrix, and vasculature. Improving the microenvironment of the liver to promote liver regeneration and repair by affecting immune function, inflammation and vasculature can regulate the dynamic imbalance between normal liver regeneration and repair and abnormal liver regeneration, thus improving the microenvironment of liver regeneration for the prevention and treatment of liver cancer. This review addresses the basic theory of the liver regeneration microenvironment, including the latest findings on immunity, inflammation and vasculature. Attention is given to the potential design of molecular targets in the microenvironment of hepatocellular carcinoma (HCC). In an effort to improve the liver regeneration microenvironment of HCC, researchers have extensively utilized the enhancement of immunity, anti-inflammation and the vasculature niche, which are discussed in detail in this review. In addition, the authors summarize the latest pro-fibrotic transition characteristics of the vascular niche and review potential cell therapies for liver disease.

Microenvironment of liver regeneration in liver cancer

The occurrence and development of liver cancer are essentially the most serious outcomes of uncontrolled liver regeneration. The progression of liver cancer is inevitably related to the abnormal microenvironment of liver regeneration. The deterioration observed in the microenvironment of liver regeneration is a necessary condition for the occurrence, development and metastasis of cancer. Therefore, the use of a technique to prevent and treat liver cancer via changes in the microenvironment of liver regeneration is a novel strategy. This strategy would be an effective way to delay, prevent or even reverse cancer occurrence, development and metastasis through an improvement in the liver regeneration microenvironment along with the integrated regulation of multiple components, targets, levels, channels and time sequences. In addition, the treatment of "tonifying Shen (Kidney) to regulate liver regeneration and repair by affecting stem cells and their microenvironment" can regulate "the dynamic imbalance between the normal liver regeneration and the abnormal liver regeneration"; this would improve the microenvironment of liver regeneration, which is also a mechanism by which liver cancer may be prevented or treated.

Microcirculation of liver cancer, microenvironment of liver regeneration, and the strategy of Chinese medicine

Microcirculation of liver cancer is the micro-vascular system which comes from the tissue of liver cancer. It can offer the nutritional requirement for accelerating the cancer cell proliferation and metastasis. The intrinsic mechanism of angiogenesis is the key link in the formation of liver cancer microcirculation system. Liver regeneration microenvironment also plays an important role in the construction of liver cancer microcirculation, through the improvement of liver regeneration microenvironment affecting tumor microcirculation is the new strategy of prevention and treatment of liver cancer. In recent years, it is found that many kinds of Chinese medicine can inhibit angiogenesis, decrease the microvessel density, and delay or prevent the development of liver cancer.

Regulation of liver regeneration: Research progress and prospect

This paper aims to review the progress and problems in research of liver regeneration regulation in recent years and to explore the solutions to these problems by performing a systematic literature review combined with the author's work. In recent years, great progress has been made in preventing and treating liver diseases by regulating liver regeneration, for example, the coordination of promotion and inhibition, the reverse inhibition and positive induction, slight adjustment and preconditioning, and overall dynamic control. Current key scientific problems in this field include distinguishing between abnormal and normal liver regeneration, mechanisms underlying their mutual transformation, objective criteria for clinical application, and quantitative indicators for judging the efficacy. The regulation of liver regeneration for preventing and treating liver diseases has become a hot research topic, and the clinical translation and application of studies remain to be promoted on the basis of further in-depth research.

The effect of hepatic progenitor cells on experimental hepatocellular carcinoma in the regenerating liver

OBJECTIVE

Liver regeneration following hepatectomy can stimulate the growth of hepatocellular carcinoma (HCC), and major hepatectomy can be associated with activation of hepatic progenitor cells (HPCs). The aim of this study was to evaluate how HPCs influence the malignant potential of tumor cells in vitro and HCC tumor growth after surgery in a rodent model.

MATERIAL AND METHODS

Hepatoma cells (JM1) were cultured with conditioned medium (CM) from syngeneic HPCs (WB-F344). Growth rate, resistance to Adriamycin, and expression patterns for invasiveness and stemness were compared with naïve JM1. Microscopic HCC tumors from naïve JM1 or JM1 cultured with CM were inoculated in Fischer 344 rats undergoing 70% hepatectomy with or without simultaneous infusion of WB-F344. Tumor growth and invasiveness-related factors were compared. Buffalo rats were induced with Morris hepatoma cells. Liver tissue from both in vivo models was examined with regard to activation of cells with progenitor-like phenotype.

RESULTS

Co-culture with CM resulted in an increased resistance to Adriamycin and enhanced expressions of α-FP, MMP9, ABCG2, CD133, and SOX2, as well as the activation of ERK, AKT, WNT, and TGF-β1 pathways. Tumor size and metastases were significantly higher in groups with co-cultured cells or HPCs infusion. After 70% hepatectomy and tumor implantation, cells positive for α-FP, CK19, and CD133 were found, thus suggesting a progenitor-like phenotype in the setting of epithelial-mesenchymal transition.

CONCLUSION

HPCs have a marked effect on HCC cells in vitro and appear to stimulate the growth and malignant potential of experimental HCC tumors.