Mechanisms of resistance to sorafenib and the corresponding strategies in hepatocellular carcinoma

Synergistic Activity of N-hydroxy-7-(2-naphthylthio) Heptanomide and Sorafenib Against Cancer Stem Cells, Anaplastic Thyroid Cancer

Anaplastic thyroid carcinoma (ATC) although rare is the most deadly form of thyroid cancer. The fatality rate for ATC is high-pitched, the survival rate at 1 year after diagnosis is <20%. Control of ATC is severely hard and widespread with unpredictability. We Previous proved that histone gene reviser and epigenetic changes role significant parts in papillary and anaplastic thyroid cancer tumorigenesis. Herein, the goal of this study was to investigate the anti-tumor activities of a HDAC inhibitor, HNHA alone and in combination with sorafenib in ATC cells in vitro and in vivo and to explore its effects on apoptotic cell death pathways. Three ATC cell lines were exposed to sorafenib in the presence or absence of HNHA, and cell viability was determined by MTT assay. Effects of combined treatment on cell cycle and intracellular signaling pathways were assessed by flow cytometry and western blot analysis. The ATC cell lines xenograft model was used to examine the anti-tumor activity in vivo. Our data showed that HNHA and sorafenib synergistically decreased cell viability in ATC cells, and also significantly increased apoptotic cell death in these cells, as proved by the cleavage of caspase-3 and DNA fragmentation. HNHA and sorafenib combination was reduced anti-apoptotic factor in ATC. Thus, combination therapy with HNHA and sorafenib significantly decreased vessel density, and most significantly reduced tumor volume and increased survival in ATC xenografts.

These results propose that HNHA in combination with sorafenib has significant anti-cancer activity in preclinical models, potentially suggesting a new clinical approach for patients of advanced thyroid cancer type.

Targeting of growth factors in the treatment of hepatocellular carcinoma: The potentials of polysaccharides

Hepatocellular carcinoma (HCC) has become a leading cause of cancer-associated mortality worldwide and is thus of great concern. Although various chemotherapeutic drugs are currently used for the treatment of HCC, severe side effects associated with these treatments have prompted interest in novel therapies, including the use of certain biological macromolecules such as polysaccharides. Several studies have shown that polysaccharides have anticancer and antiproliferative effects on HCC. Vascular endothelial growth factor, transforming growth factor β, epidermal growth factor and fibroblast growth factor may be effective targets for polysaccharides and may modulate tumor growth and immunity through increasing the expression levels of cytokines. The present review focuses on the ways in which growth factors contribute to the development of HCC, and on the anti-growth factor activities of natural and synthetic polysaccharides, as well as their effect on proinflammatory cytokines.

Focal Adhesion Kinase: Insight into Molecular Roles and Functions in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is the third leading cause of cancer-related death worldwide. Due to the high incidence of post-operative recurrence after current treatments, the identification of new and more effective drugs is required. In previous years, new targetable genes/pathways involved in HCC pathogenesis have been discovered through the help of high-throughput sequencing technologies. Mutations in TP53 and β-catenin genes are the most frequent aberrations in HCC. However, approaches able to reverse the effect of these mutations might be unpredictable. In fact, if the reactivation of proteins, such as p53 in tumours, holds great promise as anticancer therapy, there are studies arguing that chronic activation of these types of molecules may be deleterious. Thus, recently the efforts on potential targets have focused on actionable mutations, such as those occurring in the gene encoding for focal adhesion kinase (FAK). This tyrosine kinase, localized to cellular focal contacts, is over-expressed in a variety of human tumours, including HCC. Moreover, several lines of evidence demonstrated that FAK depletion or inhibition impair in vitro and in vivo HCC growth and metastasis. Here, we provide an overview of FAK expression and activity in the context of tumour biology, discussing the current evidence of its connection with HCC development and progression.

Autophagy orchestrates adaptive responses to targeted therapy in endometrial cancer

Targeted therapies in endometrial cancer (EC) using kinase inhibitors rarely result in complete tumor remission and are frequently challenged by the appearance of refractory cell clones, eventually resulting in disease relapse. Dissecting adaptive mechanisms is of vital importance to circumvent clinical drug resistance and improve the efficacy of targeted agents in EC. Sorafenib is an FDA-approved multitarget tyrosine and serine/threonine kinase inhibitor currently used to treat hepatocellular carcinoma, advanced renal carcinoma and radioactive iodine-resistant thyroid carcinoma. Unfortunately, sorafenib showed very modest effects in a multi-institutional phase II trial in advanced uterine carcinoma patients. Here, by leveraging RNA-sequencing data from the Cancer Cell Line Encyclopedia and cell survival studies from compound-based high-throughput screenings we have identified the lysosomal pathway as a potential compartment involved in the resistance to sorafenib. By performing additional functional biology studies we have demonstrated that this resistance could be related to macroautophagy/autophagy. Specifically, our results indicate that sorafenib triggers a mechanistic MAPK/JNK-dependent early protective autophagic response in EC cells, providing an adaptive response to therapeutic stress. By generating in vivo subcutaneous EC cell line tumors, lung metastatic assays and primary EC orthoxenografts experiments, we demonstrate that targeting autophagy enhances sorafenib cytotoxicity and suppresses tumor growth and pulmonary metastasis progression. In conclusion, sorafenib induces the activation of a protective autophagic response in EC cells. These results provide insights into the unopposed resistance of advanced EC to sorafenib and highlight a new strategy for therapeutic intervention in recurrent EC.

Melatonin enhances the anti-tumor effect of sorafenib via AKT/p27-mediated cell cycle arrest in hepatocarcinoma cell lines

Proposed model elucidating the role of MT in regulating the proliferation of hepatocellular carcinoma (HCC) cells treated with sorafenib.

Long non-coding RNA TUC338 is functionally involved in sorafenib-sensitized hepatocarcinoma cells by targeting RASAL1

Development of novel targeted therapy holds promise for conquering chemotherapy resistance, one of major hurdles in current liver cancer treatment. We found that long non-coding RNA TUC338 is involved in the development of hepatocellular carcinoma (HCC) and sorafenib resistance. HCC cell lines were transfected with siTUC338, then cell proliferation and invasion ability were investigated by MTT and Transwell assay. Sorafenib resistance HepG2 cells were generated to test the role of TUC338 in sorafenib sensitivity. Intratumoral delivering of siTUC338 was used to analyze the sorafenib treatment response in HepG2/Sor xenografts in vivo. Higher levels of TUC338 were found both in HCC tissues and cell lines, knockdown of TUC338 was accompanied with increased expression of RASAL1 in HCC cell line with increased proliferation and invasion ability, knockdown of TUC338 could activate the RASAL1 pathway and inhibit tumor growth genes by directly targeting RASAL1 3'-UTR. Furthermore, knockdown of TUC338 in HepG2 sorafenib sensitized its reaction to the treatment of sorafenib, which was accompanied by increased expression RASAL1; intratumoral delivering of siTUC338 could also restore sorafenib treatment response in HepG2/Sor xenografts in vivo. These findings provide direct evidence that the TUC338/RASAL1 axis might play an essential role in sorafenib-resistance of liver cancer cells, suggesting the signaling cohort could serve as a novel therapeutic target for the treatment of chemotherapy resistant liver cancer.

HBx sensitizes hepatocellular carcinoma cells to lapatinib by up-regulating ErbB3

Poor prognosis of hepatitis B virus (HBV)-associated hepatocellular carcinoma (HCC) involves HBV X protein (HBx)-induced tumor progression. HBx also contributes to chemo-resistance via inducing the expressions of anti-apoptosis and multiple drug resistance genes. However, the impact of HBx expression on the therapeutic efficacy of various receptor tyrosine kinase inhibitors remains unknown. In this study, our data showed that HBx overexpression did not alter the cellular sensitivity of HCC cell lines to sorafenib but unexpectedly enhanced the cell death induced by EGFR family inhibitors, including gefitinib, erlotinib, and lapatinib due to ErbB3 up-regulation. Mechanistically, HBx transcriptionally up-regulates ErbB3 expression in a NF-κB dependent manner. In addition, HBx also physically interacts with ErbB2 and ErbB3 proteins and enhances the formation of ErbB2/ErbB3 heterodimeric complex. The cell viability of HBx-overexpressing cells was decreased by silencing ErbB3 expression, further revealing the pivotal role of ErbB3 in HBx-mediated cell survival. Our data suggest that HBx shifts the oncogenic addiction of HCC cells to ErbB2/ErbB3 signaling pathway via inducing ErbB3 expression and thereby enhances their sensitivity to EGFR/ErbB2 inhibitors.

miR-181a induces sorafenib resistance of hepatocellular carcinoma cells through downregulation of RASSF1 expression

Sorafenib, a multi-kinase inhibitor, is the only standard clinical drug for patients with advanced hepatocellular carcinoma (HCC); however, development of sorafenib resistance in HCC often prevents its long-term efficacy. Therefore, novel targets and strategies are urgently needed to improve the antitumor effect of sorafenib. In the present study, we examined the novel mechanisms of sorafenib resistance of HCC cells by investigating the difference in sorafenib sensitivity between two HCC cell lines. Sorafenib induced more apoptosis of HepG2 cells compared to Hep3B cells. Sorafenib exposure to HepG2 cells but not Hep3B cells increased the expression of proapoptotic factor PUMA, and activated PARP and caspase-3. Notably, microRNA-181a (miR-181a) expression levels were lower in HepG2 cells than in Hep3B cells. Exogenous miR-181a expression in HepG2 cells reduced apoptosis, whereas inhibition of miR-181a in Hpe3B cells increased apoptosis. In addition, we demonstrated that miR-181a directly targets RASSF1, a MAPK signaling factor, and knockdown of RASSF1 increased sorafenib resistance. Taken together, these results suggest that miR-181a provokes sorafenib resistance through suppression of RASSF1. Our data provide important insight into the novel therapeutic strategy against sorafenib resistance of HCC cells by targeting of miR-181a pathway.

Sorafenib potentiates ABT-737-induced apoptosis in human oral cancer cells

OBJECTIVE

The mimetic BH3 ABT-737, a potent inhibitor of anti-apoptotic Bcl-2 family proteins, has potential as anti-cancer drug in many cancers. Recently, patients treated with ABT-737 have developed drug tolerance during cancer therapy. Therefore, we examined whether ABT-737 is effective in killing MC-3 and HSC-3 human oral cancer cells either alone or in combination with the oncogenic kinase inhibitor, sorafenib.

DESIGN

The potentiating activities of sorafenib in ABT-737-induced apoptosis were determined using trypan blue exclusion assay, DAPI staining, cell viability assay and Western blot analysis.

RESULTS

Combined use of ABT-737 and sorafenib synergistically suppressed cell viability and induced apoptosis compared with either compound individually. The combination of ABT-737 and sorafenib altered only Bax and Bak proteins and their activations, resulting in mitochondrial translocation of Bax from the cytosol. Additionally, combination treatment-mediated apoptosis may be correlated with ERK and STAT3 pathways.

CONCLUSIONS

These results suggest that sorafenib may effectively overcome ABT-737 resistance to apoptotic cell death, which can be a new potential chemotherapeutic strategy against human oral cancer.

Inhibition of acquired-resistance hepatocellular carcinoma cell growth by combining sorafenib with phosphoinositide 3-kinase and rat sarcoma inhibitor

BACKGROUND

To provide support for combined usage of phosphoinositide 3-kinase (PI3K) inhibitors or mitogen-activated protein kinase pathway inhibitors together with sorafenib in treatment of sorafenib-resistant hepatocellular carcinoma.

MATERIALS AND METHODS

The sorafenib-resistant cell lines were established to evaluate the effects of MK-2206 2HCL, a dual PI3K/mammalian target of rapamycin (mTOR) inhibitor, and PD0325901, an rat sarcoma (RAS) and/or extracellular signal-regulated kinase (ERK) inhibitor, on cell proliferation and apoptosis, as both single and combined treatments with sorafenib. In addition, multidrug resistance 1 gene expression, mutation status of key members in PI3K/mTOR, and RAS/ERK pathways and pathway activation were analyzed to identify predictors of drug response.

RESULTS

Molecular studies reveal that combining MK-2206 2HCL or PD0325901 with sorafenib not only has a synergistic effect, in suppressing PI3K/protein kinase B/mTOR and RAS/MEK/ERK signaling more effectively than either treatment alone, but also prevents the cross activation of the other pathway that occurs with single treatments in both sorafenib sensitive and resistant lines. PD0325901 exhibited a stronger synergic effect with sorafenib than MK-2206 2HCL. Sorafenib-resistant cell lines were characterized by activation of both of the two pathways, as indicated by multidrug resistance 1 gene expression profiles and pathway activity analysis.

CONCLUSIONS

Our studies have showed that both inhibitors of PI3K/mTOR and RAS/ERK signaling are potentially effective antihepatocellular carcinoma drugs especially in treating sorafenib-resistant hepatocellular carcinoma.

Inactivation of hypoxia-induced YAP by statins overcomes hypoxic resistance tosorafenib in hepatocellular carcinoma cells

Sorafenib is a multikinase inhibitor used as a first-line treatment for advanced hepatocellular carcinoma (HCC), but it has shown modest to low response rates. The characteristic tumour hypoxia of advanced HCC maybe a major factor underlying hypoxia-mediated treatment failure. Thus, it is urgent to elucidate the mechanisms of hypoxia-mediated sorafenib resistance in HCC. In this study, we found that hypoxia induced the nuclear translocation of Yes associate-Protein (YAP) and the subsequent transactivation of target genes that promote cell survival and escape apoptosis, thereby leading to sorafenib resistance. Statins, the inhibitors of hydroxymethylglutaryl-CoA reductase, could ameliorate hypoxia-induced nuclear translocation of YAP and suppress mRNA levels of YAP target genes both in vivo and in vitro. Combined treatment of statins with sorafenib greatly rescued the loss of anti-proliferative effects of sorafenib under hypoxia and improved the inhibitory effects on HepG2 xenograft tumour growth, accompanied by enhanced apoptosis as evidenced by the increased sub-G1 population and PARP cleavage. The expression levels of YAP and its target genes were highly correlated with poor prognosis and predicted a high risk of HCC patients. These findings collectively suggest that statins utilization maybe a promising new strategy to counteract hypoxia-mediated resistance to sorafenib in HCC patients.

The clinical effect and relevant mechanism of combined sorafenib and radiofrequency ablation in the treatment of early small hepatocellular carcinoma

The number of cases with hepatocellular carcinoma (HCC) are on the increase. The aim of the present study was to investigate the clinical effect and relevant mechanism of combined sorafenib and radiofrequency ablation (RFA) in the treatment of the early small HCC. A total of 120 cases of patients with small HCC that presented during the period of May 2007 to June 2010 were selected and divided into the surgery (n=60) and RF (n=60) groups according to the treatment method employed. The surgery group was treated with a laparotomy resection and the RF group was treated with combined sorafenib and RFA, and a comparative analysis was made between the two groups with regard to recurrence rates, adverse reactions, and survival rates. After treatment of 1 month, the radical effective rate of the surgery and RF groups was 100%. Contrast-enhanced ultrasound images of the patients in the RF group were taken. During the 5-year follow-up, the tumor recurrence rate in the surgery group was 18.3%, significantly lower than that in the RF group where the tumor recurrence rate was 38.3% (P<0.05). The occurrence rate of postoperative pain, fever, abdominal bleeding, infection, and other complications of patients in the surgery group was significantly higher than the complication occurrence rate (P<0.05) of the patients in the RF group. The average survival time of the patients in the surgery group was 51.2±1.5 months and the survival rates during the first, third and fifth year were 90.7, 71.5 and 56.7%, respectively. Additionally, the average survival time of the patients in the RF group was 64.6±2.4 months and the survival rates during the first, third and fifth year were 91.1, 72.8 and 57.5%, respectively. The difference between the two groups was not statistically significant. The tumor-free survival rates in the surgery group during the first, third and fifth year were 87.8, 44.3 and 33.2%, respectively, while the tumor-free survival rates in the RF group during the first, third and fifth year were 86.2, 48.3 and 34.6%, respectively, and the difference between the two groups was not statistically significant. In conclusion, the combined sorafenib and RFA method, and laparotomy resection method have their advantages in the treatment of early small HCC, and under specific medical conditions, the former can partially replace the latter and be used as a preferred treatment means in the treatment of early small HCC.

Time for paradigm change in management of hepatocellular carcinoma: is a personalized approach on the horizon?

Hepatocellular carcinoma (HCC) is the fifth most frequent cancer form but the second leading cause of all cancer-related deaths. There are several reasons for high mortality in the HCC cohort: lack of effective screening programs and consequently late diagnosis, multifactorial origin with cumulative risk factors, complex carcinogenesis, tumor heterogeneity, unpredictable impacts of individual microenvironment on tumor development and progression, and, as the consequence, frequently untargeted therapy and cancer resistance toward currently applied treatment approaches. The currently applied 'treat and wait' approach is inappropriate in the overall HCC management. Urgent need in paradigm change toward predictive, preventive and personalized medicine is discussed in this review article. Innovative strategies for an advanced predictive, preventive and personalized medicine approach in the overall HCC management benefiting the patient are presented.

Precision medicine for hepatocellular carcinoma: Perspectives and obstacles

Hepatocellular carcinoma (HCC) is one of the most common cancers in China. HCC patients have a poor prognosis due to the lack of effective drugs. The marketing of sorafenib in 2007 has terminated the history that there is no effective drug for HCC. Unfortunately, sorafenib prolongs the survival of advanced HCC patients by only 2-3 mo, and remains the unique systemic drug as no alternative effective agents have been demonstrated to be superior to sorafenib in treating HCC. Precision medicine, a novel concept and medicinal model, has recently emerged and been spreading globally, with the development of gene sequencing techniques, bioinformatics, big data and so on. Detecting, analyzing, verifying and utilizing the specific tumor biomarkers with the advanced technology have made it possible to apply "personalized and precision therapy" in the treatment of advanced HCC. In the present article we summarize the recent progress of HCC therapy under the guidance of precision medicine, and analyze the major obstacles for its clinical application, with an aim to provide some new clues for clinicians and researchers engaged in the clinical and basic research of HCC.

Transposon mutagenesis identifies genes and cellular processes driving epithelial-mesenchymal transition in hepatocellular carcinoma

Epithelial-mesenchymal transition (EMT) is thought to contribute to metastasis and chemoresistance in patients with hepatocellular carcinoma (HCC), leading to their poor prognosis. The genes driving EMT in HCC are not yet fully understood, however. Here, we show that mobilization of Sleeping Beauty (SB) transposons in immortalized mouse hepatoblasts induces mesenchymal liver tumors on transplantation to nude mice. These tumors show significant down-regulation of epithelial markers, along with up-regulation of mesenchymal markers and EMT-related transcription factors (EMT-TFs). Sequencing of transposon insertion sites from tumors identified 233 candidate cancer genes (CCGs) that were enriched for genes and cellular processes driving EMT. Subsequent trunk driver analysis identified 23 CCGs that are predicted to function early in tumorigenesis and whose mutation or alteration in patients with HCC is correlated with poor patient survival. Validation of the top trunk drivers identified in the screen, including MET (MET proto-oncogene, receptor tyrosine kinase), GRB2-associated binding protein 1 (GAB1), HECT, UBA, and WWE domain containing 1 (HUWE1), lysine-specific demethylase 6A (KDM6A), and protein-tyrosine phosphatase, nonreceptor-type 12 (PTPN12), showed that deregulation of these genes activates an EMT program in human HCC cells that enhances tumor cell migration. Finally, deregulation of these genes in human HCC was found to confer sorafenib resistance through apoptotic tolerance and reduced proliferation, consistent with recent studies showing that EMT contributes to the chemoresistance of tumor cells. Our unique cell-based transposon mutagenesis screen appears to be an excellent resource for discovering genes involved in EMT in human HCC and potentially for identifying new drug targets.

Galectin-1 induces hepatocellular carcinoma EMT and sorafenib resistance by activating FAK/PI3K/AKT signaling

Galectin-1 (Gal-1) is involved in several pathological activities associated with tumor progression and chemoresistance, however, the role and molecular mechanism of Gal-1 activity in hepatocellular carcinoma (HCC) epithelial-mesenchymal transition (EMT) and sorafenib resistance remain enigmatic. In the present study, forced Gal-1 expression promoted HCC progression and sorafenib resistance. Gal-1 elevated αvβ3-integrin expression, leading to AKT activation. Moreover, Gal-1 overexpression induced HCC cell EMT via PI3K/AKT cascade activation. Clinically, our data revealed that Gal-1 overexpression is correlated with poor HCC survival outcomes and sorafenib response. These data suggest that Gal-1 may be a potential therapeutic target for HCC and a biomarker for predicting response to sorafenib treatment.

Activation of c-Jun predicts a poor response to sorafenib in hepatocellular carcinoma: Preliminary Clinical Evidence

We determined the mitogen-activated protein kinase (MAPK) gene expression profile of acquired resistance in sorafenib-sensitive hepatocellular carcinoma (HCC) cells and aimed to identify c-Jun as an important molecule mediating the efficacy of sorafenib. Differences in gene expression of the MAPK signaling between untreated and sorafenib-treated HCC cell lines were investigated using real-time polymerase chain reaction array. Western blot and real-time PCR further evaluated the expression of c-Jun. Pathological specimens from 50 patients with advanced HCC were collected to measure p-c-Jun expression. Sorafenib-resistant HCC cells demonstrated greater levels of basal c-Jun mRNA and protein compared with sorafenib-sensitive HCC cells. Sorafenib activated p-c-Jun in a dose- and time-dependent manner in PLC/PRF/5 and MHCC97H cell lines. Decreased expression levels of 6 genes after sorafenib treatment suggested a robust inhibitory impact of sorafenib on MAPK signaling in HCC cells. c-Jun and p-c-Jun expression levels were inversely correlated with the efficacy of sorafenib; a high expression level of p-c-Jun was associated with resistance to sorafenib and poor overall survival in patients with clinical HCC. p-c-Jun may act as a biomarker for predicting responses of sorafenib treatment, thus advocating targeting of JNK/c-Jun signaling as an optimal therapeutic strategy in a subset of HCC.

Synergistic Effect and Molecular Mechanisms of Traditional Chinese Medicine on Regulating Tumor Microenvironment and Cancer Cells

The interaction of tumor cells with the microenvironment is like a relationship between the “seeds” and “soil,” which is a hotspot in recent cancer research. Targeting at tumor microenvironment as well as tumor cells has become a new strategy for cancer treatment. Conventional cancer treatments mostly focused on single targets or single mechanism (the seeds or part of the soil); few researches intervened in the whole tumor microenvironment and achieved ideal therapeutic effect as expected. Traditional Chinese medicine displays a broad range of biological effects, and increasing evidence has shown that it may relate with synergistic effect on regulating tumor microenvironment and cancer cells. Based on literature review and our previous studies, we summarize the synergistic effect and the molecular mechanisms of traditional Chinese medicine on regulating tumor microenvironment and cancer cells.

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.

Hepatocellular carcinoma: Where are we?

Hepatocellular carcinoma (HCC) is the second cause of death due to malignancy in the world, following lung cancer. The geographic distribution of this disease accompanies its principal risk factors: Chronic hepatitis B virus and hepatitis C virus infection, alcoholism, aflatoxin B1 intoxication, liver cirrhosis, and some genetic attributes. Recently, type II diabetes has been shown to be a risk factor for HCC together with obesity and metabolic syndrome. Although the risk factors are quite well known and it is possible to diagnose HCC when the tumor is less than 1 cm diameter, it remains elusive at the beginning and treatment is often unsuccessful. Liver transplantation is thus far considered the best treatment for HCC as it cures HCC and the underlying liver disease. Using the Milan criteria, overall survival after liver transplantation for HCC is about 70% after 5 years. Many attempts have been made to go beyond the Milan Criteria and according to recent works reasonably good results have been achieved by using a histochemical marker such as cytokeratine 19 and the so-called "up to seven criteria" to divide patients into categories according to their risk of relapse. In addition to liver transplantation other therapies have been proposed such as resection, tumor ablation by different means, embolization and chemotherapy. An important step in the treatment of advanced HCC has been the introduction of sorafenib, the first oral, systemic drug that has provided significant improvement in survival. Treatment of HCC patients must be multidisciplinary and by using the different approaches discussed in this review it is possible to offer prolonged survival and quite good and sometimes even excellent quality of life to many patients.

Activation of the p62-Keap1-NRF2 pathway protects against ferroptosis in hepatocellular carcinoma cells

Ferroptosis is a recently recognized form of regulated cell death caused by an iron-dependent accumulation of lipid reactive oxygen species. However, the molecular mechanisms regulating ferroptosis remain obscure. Here, we report that nuclear factor erythroid 2-related factor 2 (NRF2) plays a central role in protecting hepatocellular carcinoma (HCC) cells against ferroptosis. Upon exposure to ferroptosis-inducing compounds (e.g., erastin, sorafenib, and buthionine sulfoximine), p62 expression prevented NRF2 degradation and enhanced subsequent NRF2 nuclear accumulation through inactivation of Kelch-like ECH-associated protein 1. Additionally, nuclear NRF2 interacted with transcriptional coactivator small v-maf avian musculoaponeurotic fibrosarcoma oncogene homolog proteins such as MafG and then activated transcription of quinone oxidoreductase-1, heme oxygenase-1, and ferritin heavy chain-1. Knockdown of p62, quinone oxidoreductase-1, heme oxygenase-1, and ferritin heavy chain-1 by RNA interference in HCC cells promoted ferroptosis in response to erastin and sorafenib. Furthermore, genetic or pharmacologic inhibition of NRF2 expression/activity in HCC cells increased the anticancer activity of erastin and sorafenib in vitro and in tumor xenograft models.

CONCLUSION

These findings demonstrate novel molecular mechanisms and signaling pathways of ferroptosis; the status of NRF2 is a key factor that determines the therapeutic response to ferroptosis-targeted therapies in HCC cells.

Activation of the p62-Keap1-NRF2 pathway protects against ferroptosis in hepatocellular carcinoma cells

Ferroptosis is a recently recognized form of regulated cell death caused by an iron-dependent accumulation of lipid reactive oxygen species. However, the molecular mechanisms regulating ferroptosis remain obscure. Here, we report that nuclear factor erythroid 2-related factor 2 (NRF2) plays a central role in protecting hepatocellular carcinoma (HCC) cells against ferroptosis. Upon exposure to ferroptosis-inducing compounds (e.g., erastin, sorafenib, and buthionine sulfoximine), p62 expression prevented NRF2 degradation and enhanced subsequent NRF2 nuclear accumulation through inactivation of Kelch-like ECH-associated protein 1. Additionally, nuclear NRF2 interacted with transcriptional coactivator small v-maf avian musculoaponeurotic fibrosarcoma oncogene homolog proteins such as MafG and then activated transcription of quinone oxidoreductase-1, heme oxygenase-1, and ferritin heavy chain-1. Knockdown of p62, quinone oxidoreductase-1, heme oxygenase-1, and ferritin heavy chain-1 by RNA interference in HCC cells promoted ferroptosis in response to erastin and sorafenib. Furthermore, genetic or pharmacologic inhibition of NRF2 expression/activity in HCC cells increased the anticancer activity of erastin and sorafenib in vitro and in tumor xenograft models.

CONCLUSION

These findings demonstrate novel molecular mechanisms and signaling pathways of ferroptosis; the status of NRF2 is a key factor that determines the therapeutic response to ferroptosis-targeted therapies in HCC cells.

Designing a broad-spectrum integrative approach for cancer prevention and treatment

Targeted therapies and the consequent adoption of "personalized" oncology have achieved notable successes in some cancers; however, significant problems remain with this approach. Many targeted therapies are highly toxic, costs are extremely high, and most patients experience relapse after a few disease-free months. Relapses arise from genetic heterogeneity in tumors, which harbor therapy-resistant immortalized cells that have adopted alternate and compensatory pathways (i.e., pathways that are not reliant upon the same mechanisms as those which have been targeted). To address these limitations, an international task force of 180 scientists was assembled to explore the concept of a low-toxicity "broad-spectrum" therapeutic approach that could simultaneously target many key pathways and mechanisms. Using cancer hallmark phenotypes and the tumor microenvironment to account for the various aspects of relevant cancer biology, interdisciplinary teams reviewed each hallmark area and nominated a wide range of high-priority targets (74 in total) that could be modified to improve patient outcomes. For these targets, corresponding low-toxicity therapeutic approaches were then suggested, many of which were phytochemicals. Proposed actions on each target and all of the approaches were further reviewed for known effects on other hallmark areas and the tumor microenvironment. Potential contrary or procarcinogenic effects were found for 3.9% of the relationships between targets and hallmarks, and mixed evidence of complementary and contrary relationships was found for 7.1%. Approximately 67% of the relationships revealed potentially complementary effects, and the remainder had no known relationship. Among the approaches, 1.1% had contrary, 2.8% had mixed and 62.1% had complementary relationships. These results suggest that a broad-spectrum approach should be feasible from a safety standpoint. This novel approach has potential to be relatively inexpensive, it should help us address stages and types of cancer that lack conventional treatment, and it may reduce relapse risks. A proposed agenda for future research is offered.

Bufalin Reverses Resistance to Sorafenib by Inhibiting Akt Activation in Hepatocellular Carcinoma: The Role of Endoplasmic Reticulum Stress

Sorafenib is the standard first-line therapeutic treatment for patients with advanced hepatocellular carcinoma (HCC), but its use is hampered by the development of drug resistance. The activation of Akt by sorafenib is thought to be responsible for this resistance. Bufalin is the major active ingredient of the traditional Chinese medicine Chan su, which inhibits Akt activation; therefore, Chan su is currently used in the clinic to treat cancer. The present study aimed to investigate the ability of bufalin to reverse both inherent and acquired resistance to sorafenib. Bufalin synergized with sorafenib to inhibit tumor cell proliferation and induce apoptosis. This effect was at least partially due to the ability of bufalin to inhibit Akt activation by sorafenib. Moreover, the ability of bufalin to inactivate Akt depended on endoplasmic reticulum (ER) stress mediated by inositol-requiring enzyme 1 (IRE1). Silencing IRE1 with siRNA blocked the bufalin-induced Akt inactivation, but silencing eukaryotic initiation factor 2 (eIF2) or C/EBP-homologous protein (CHOP) did not have the same effect. Additionally, silencing Akt did not influence IRE1, CHOP or phosphorylated eIF2α expression. Two sorafenib-resistant HCC cell lines, which were established from human HCC HepG2 and Huh7 cells, were refractory to sorafenib-induced growth inhibition but were sensitive to bufalin. Thus, Bufalin reversed acquired resistance to sorafenib by downregulating phosphorylated Akt in an ER-stress-dependent manner via the IRE1 pathway. These findings warrant further studies to examine the utility of bufalin alone or in combination with sorafenib as a first- or second-line treatment after sorafenib failure for advanced HCC.

Contradictory Relationships between Cancer and Normal Cells and Implications for Anti-cancer Therapy

Cancer treatment remains a serious problem worldwide. Analysis of the relationship between cancer cells and normal cells reveals that these two share characteristics in contradiction, thus could be analyzed by using contradictory principles. Under the theory of contradictory principles, induction of a dormant state or reversal of cancer cells is an important treatment strategy beyond traditional cytotoxic therapy. Normal cells are also the targets and under the influence of anti-cancer treatments and should be considered during therapy. Findings based on crosstalk between these two cell types may offer opportunities for the development of new biomarkers and therapies.

Regulation of cell death receptor S-nitrosylation and apoptotic signaling by Sorafenib in hepatoblastoma cells

Nitric oxide (NO) plays a relevant role during cell death regulation in tumor cells. The overexpression of nitric oxide synthase type III (NOS-3) induces oxidative and nitrosative stress, p53 and cell death receptor expression and apoptosis in hepatoblastoma cells. S-nitrosylation of cell death receptor modulates apoptosis. Sorafenib is the unique recommended molecular-targeted drug for the treatment of patients with advanced hepatocellular carcinoma. The present study was addressed to elucidate the potential role of NO during Sorafenib-induced cell death in HepG2 cells. We determined the intra- and extracellular NO concentration, cell death receptor expression and their S-nitrosylation modifications, and apoptotic signaling in Sorafenib-treated HepG2 cells. The effect of NO donors on above parameters has also been determined. Sorafenib induced apoptosis in HepG2 cells. However, low concentration of the drug (10nM) increased cell death receptor expression, as well as caspase-8 and -9 activation, but without activation of downstream apoptotic markers. In contrast, Sorafenib (10 µM) reduced upstream apoptotic parameters but increased caspase-3 activation and DNA fragmentation in HepG2 cells. The shift of cell death signaling pathway was associated with a reduction of S-nitrosylation of cell death receptors in Sorafenib-treated cells. The administration of NO donors increased S-nitrosylation of cell death receptors and overall induction of cell death markers in control and Sorafenib-treated cells. In conclusion, Sorafenib induced alteration of cell death receptor S-nitrosylation status which may have a relevant repercussion on cell death signaling in hepatoblastoma cells.

Chronic hepatitis B virus and hepatitis C virus infections and cancer: synergy between viral and host factors

Hepatitis B virus (HBV) or hepatitis C virus (HCV) infections represent major causes of chronic liver disease and hepatocellular carcinoma. Despite inducing shared pathological events leading to oncogenic transformation, these two viruses present profound differences in their molecular features, life cycle and interplay with host factors, which significantly differentiate the prognostic and therapeutic approach to the related diseases. In the present review, we report the main mechanisms involved in the multistep process leading from HCV/HBV infection and cancer development, discussing side-by-side the analogies and differences between the two viruses. Such events can be broadly categorized into (a) direct oncogenic effects, involving integration in the host genome (in the case of HBV) and chromosomal instability, interference with oncosuppressor pathways, induction of oxidative stress, promotion of angiogenesis, epithelial-mesenchymal transition, alterations in the epigenetic asset and interaction with non-coding RNAs; and (b) indirect activities mostly mediated by host events, including chronic inflammation sustained by peculiar cytokine networks (such as interleukin-6 and lymphotoxins), metabolic dysfunctions promoted by steatohepatitis, interplay with gut microbiota and fibrotic events (mainly in HCV infection). This scenario suggests that the integrated study of viral and host factors may lead to the successful development of novel biomarkers and targets for therapy.

Current systemic treatment of hepatocellular carcinoma: A review of the literature

Hepatocellular carcinoma (HCC) is the fifth most common form of human cancer worldwide and the third most common cause of cancer-related deaths. The strategies of various treatments for HCC depend on the stage of tumor, the status of patient's performance and the reserved hepatic function. The Barcelona Clinic Liver Cancer (BCLC) staging system is currently used most for patients with HCC. For example, for patients with BCLC stage 0 (very early stage) and stage A (early stage) HCC, the curable treatment modalities, including resection, transplantation and radiofrequency ablation, are taken into consideration. If the patients are in BCLC stage B (intermediate stage) and stage C (advanced stage) HCC, they may need the palliative transarterial chemoembolization and even the target medication of sorafenib. In addition, symptomatic treatment is always recommended for patients with BCLC stage D (end stage) HCC. In this review, we will attempt to summarize the historical perspective and the current developments of systemic therapies in BCLC stage B and C in HCC.

Targeting hypoxia-inducible factor-2α enhances sorafenib antitumor activity via β-catenin/C-Myc-dependent pathways in hepatocellular carcinoma

Sorafenib is a type of multikinase inhibitor that exhibits antiangiogenic and antiproliferative effects; in addition, sorafenib is a unique first-line drug recommended for the treatment of advanced hepatocellular carcinoma (HCC). However, the effectiveness of HCC treatment remains poor due to acquired drug resistance. It has been suggested that hypoxia, induced as a results of the antiangiogenic effects of sustained sorafenib treatment, may be an important factor in sorafenib resistance. The transcription factor hypoxia-inducible factor (HIF)-2α has been reported to be associated with cell proliferation under hypoxic conditions; therefore, it was hypothesized that hypoxia may enhance tumor cell proliferation via this mechanism. The present study aimed to evaluate whether the knock-down of HIF-2α was able to enhance the therapeutic efficacy of sorafenib in order to effectively treat HCC. The results demonstrated that hypoxia protected HCC cells against sorafenib; however, short hairpin RNA-HIF-2α transfection in combination with sorafenib treatment exhibited a significantly synergistic effect against HCC cell proliferation. In addition, HCC cells acquired increased β-catenin/C-Myc expression, which enhanced proliferation under hypoxic conditions; however, targeted knock-down of HIF-2α or C-Myc markedly decreased cell proliferation in HCC cells. In conclusion, the results of the present study indicated that the targeted knock-down of HIF-2α in combination with sorafenib may be a promising strategy for the treatment of HCC.

Disruption of a regulatory loop between DUSP1 and p53 contributes to hepatocellular carcinoma development and progression

BACKGROUND & AIMS

Altered expression of dual specificity phosphatase 1 (DUSP1) is common in tumors including hepatocellular carcinoma (HCC), and is predictive of tumor progression and poor prognosis. However, the tumor suppressive role of DUSP1 has yet to be clearly elucidated.

METHODS

The molecular mechanisms of tumor suppression that were investigated were induction of apoptosis, cell cycle inhibition, and regulation of p53. Additionally, the antitumor effect of DUSP1 was assessed using a mouse model. Associated signaling pathways in HCC cells and tissues were examined.

RESULTS

Downregulation of DUSP1 expression was significantly correlated with poor differentiation (p<0.001) and advanced HCC stage (p=0.023). DUSP1 expression resulted in HCC suppression and longer survival (p=0.0002) in a xenoplant mice model. DUSP1 inhibited p38 MAPK phosphorylation and subsequently suppressed HSP27 activation, resulting in enhanced p53 phosphorylation at sites S15, S20, and S46 in HCC cells. Enhanced p53 activation induced the expression of target genes p21 and p27, which are linked to cell cycle arrest and apoptosis. Thus, DUSP1 was potentially linked to p53 activation via the p38 MAPK/HSP27 pathway. Wild-type but not mutant p53 transcriptionally upregulated DUSP1 via its DNA-binding domain. DUSP1 and p53 might collaborate to suppress tumors in hepatocarcinogenesis via a positive regulatory loop.

CONCLUSIONS

Our results revealed that disruption of a positive regulatory loop between DUSP1 and p53 promoted HCC development and progression, providing a rationale for a therapeutic agent that restores DUSP1 in HCC.

Arsenic trioxide potentiates the anti-cancer activities of sorafenib against hepatocellular carcinoma by inhibiting Akt activation

Sorafenib is the standard first-line systemic drug for advanced hepatocellular carcinoma (HCC), but it also induces the activation of Akt, which contributes to the mechanisms for the resistance to sorafenib. Arsenic trioxide (ATO) is a currently clinically used anticancer drug and displays its anticancer activities by inhibiting Akt activation. Therefore, we hypothesized that ATO may potentiate the anti-cancer activities of sorafenib against HCC. The results have demonstrated that ATO synergized with sorafenib to inhibit the proliferation and promote the apoptosis of HCC cells by diminishing the increased activation of Akt by sorafenib. ATO was shown to inhibit the expression or activation of Akt downstream factors, including glycogen synthase kinase (GSK)-3β, mammalian target of rapamycin (mTOR), ribosomal protein S6 kinase (S6K), and eukaryotic translation initiation factor 4E-binding protein 1 (4EBP1), which regulate cell apoptosis and were upregulated or activated by sorafenib. Both sorafenib and ATO downregulated the expression of cyclin D1, resulting in HCC cells arrested at G0/G1 phase. ATO downregulated the expression of Bcl-2 and Bcl-xL and upregulated the expression of Bax, indicating that ATO could induce the apoptosis of HCC cells through the intrinsic pathways; but sorafenib showed little effects on these proteins of Bcl-2 family. ATO synergized with sorafenib to suppress the growth of HCC tumors established in mice by inhibiting the proliferation and inducing the apoptosis of HCC cells in situ. These results indicate that ATO may be a potential agent that given in combination with sorafenib acts synergistically for treating HCC.

T7 peptide inhibits angiogenesis via downregulation of angiopoietin-2 and autophagy

Angiogenesis is required for the invasion, metastasis and chemoresistance of tumor cells. In addition to vascular endothelial cell growth factor (VEGF), angiopoietin-2 (Ang2) is considered to be a promising target for anti-angiogenic therapy. The T7 peptide, an active fragment of full-length tumstatin [the noncollagenous 1 domain of the type IV collagen α3 chain, α3(IV)NC1], has equivalent anti-angiogenic activity to that of full-length tumstatin. This study aimed to explore the mechanisms of the T7 peptide in the regulation of Ang2 expression in endothelial cells (ECs) as well as inhibition of angiogenesis and invasion of hepatocellular carcinoma cells. We also examined the role of autophagy in angiogenesis. Human umbilical vein endothelial cells (HUVECs) were incubated with endothelial cell medium (ECM)-2 in a hypoxia chamber to mimic hypoxic conditions. The recombinant T7 peptide inhibited the cell viability, tube formation and induced apoptosis of the HUVECs. The T7 peptide downregulated the protein expression of Ang2 by inhibiting phosphorylation of AKT under hypoxic conditions. The migration of HUVECs and invasion of HepG2 cells were inhibited by the T7 peptide via inhibition of Ang2 expression. EC autophagy was induced by the T7 peptide. Inhibition of autophagy enhanced the anti‑angiogenic activity of the T7 peptide by increasing EC apoptosis. In vivo, immunohistochemistry of VE-cadherin and CD31 showed that angiogenesis was decreased significantly by the T7 peptide in a nude mouse xenogeneic tumor model. In conclusion, the T7 peptide inhibited angiogenesis and exerted its antitumor effects by inhibition of Ang2, phosphorylation of AKT and matrix metalloproteinase-2 (MMP-2) regulated by Ang2. Furthermore, inhibition of autophagy may significantly enhance the anti-angiogenic activity of the T7 peptide.

Preclinical trials for prevention of tumor progression of hepatocellular carcinoma by LZ-8 targeting c-Met dependent and independent pathways

Hepatocellular carcinoma (HCC) is among the most lethal cancers. Mounting studies highlighted the essential role of the HGF/c-MET axis in driving HCC tumor progression. Therefore, c-Met is a potential therapeutic target for HCC. However, several concerns remain unresolved in c-Met targeting. First, the status of active c-Met in HCC must be screened to determine patients suitable for therapy. Second, resistance and side effects have been observed frequently when using conventional c-Met inhibitors. Thus, a preclinical system for screening the status of c-Met signaling and identifying efficient and safe anti-HCC agents is urgently required. In this study, immunohistochemical staining of phosphorylated c-Met (Tyr1234) on tissue sections indicated that HCCs with positive c-Met signaling accounted for approximately 46% in 26 cases. Second, many patient-derived HCC cell lines were established and characterized according to motility and c-Met signaling status. Moreover, LZ8, a medicinal peptide purified from the herb Lingzhi, featuring immunomodulatory and anticancer properties, was capable of suppressing cell migration and slightly reducing the survival rate of both c-Met positive and negative HCCs, HCC372, and HCC329, respectively. LZ8 also suppressed the intrahepatic metastasis of HCC329 in SCID mice. On the molecular level, LZ8 suppressed the expression of c-Met and phosphorylation of c-Met, ERK and AKT in HCC372, and suppressed the phosphorylation of JNK, ERK, and AKT in HCC329. According to receptor array screening, the major receptor tyrosine kinase activated in HCC329 was found to be the epidermal growth factor receptor (EGFR). Moreover, tyrosine-phosphorylated EGFR (the active EGFR) was greatly suppressed in HCC329 by LZ8 treatment. In addition, LZ8 blocked HGF-induced cell migration and c-Met-dependent signaling in HepG2. In summary, we designed a preclinical trial using LZ8 to prevent the tumor progression of patient-derived HCCs with c-Met-positive or -negative signaling.

Poly(vinyl alcohol)/gelatin Hydrogels Cultured with HepG2 Cells as a 3D Model of Hepatocellular Carcinoma: A Morphological Study

It has been demonstrated that three-dimensional (3D) cell culture models represent fundamental tools for the comprehension of cellular phenomena both for normal and cancerous tissues. Indeed, the microenvironment affects the cellular behavior as well as the response to drugs. In this study, we performed a morphological analysis on a hepatocarcinoma cell line, HepG2, grown for 24 days inside a bioartificial hydrogel composed of poly(vinyl alcohol) (PVA) and gelatin (G) to model a hepatocellular carcinoma (HCC) in 3D. Morphological features of PVA/G hydrogels were investigated, resulting to mimic the trabecular structure of liver parenchyma. A histologic analysis comparing the 3D models with HepG2 cell monolayers and tumor specimens was performed. In the 3D setting, HepG2 cells were viable and formed large cellular aggregates showing different morphotypes with zonal distribution. Furthermore, β-actin and α5β1 integrin revealed a morphotype-related expression; in particular, the frontline cells were characterized by a strong immunopositivity on a side border of their membrane, thus suggesting the formation of lamellipodia-like structures apt for migration. Based on these results, we propose PVA/G hydrogels as valuable substrates to develop a long term 3D HCC model that can be used to investigate important aspects of tumor biology related to migration phenomena.

Role of anti-angiogenesis therapy in the management of hepatocellular carcinoma: The jury is still out

As the leading cause of disease-related deaths, cancer is a major public health threat worldwide. Surgical resection is still the first-line therapy for patients with early-stage cancers. However, postoperative relapse and metastasis remain the cause of 90% of deaths of patients with solid organ malignancies, including hepatocellular carcinoma (HCC). With the rapid development of molecular biology techniques in recent years, molecularly targeted therapies using monoclonal antibodies, small molecules, and vaccines have become a milestone in cancer therapeutic by significantly improving the survival of cancer patients, and have opened a window of hope for patients with advanced cancer. Hypervascularization is a major characteristic of HCC. It has been reported that anti-angiogenic treatments, which inhibit blood vessel formation, are highly effective for treating HCC. However, the efficacy and safety of anti-angiogenesis therapies remain controversial. Sorafenib is an oral multikinase inhibitor with anti-proliferative and anti-angiogenic effects and is the first molecular target drug approved for the treatment of advanced HCC. While sorafenib has shown promising therapeutic effects, substantial evidence of primary and acquired resistance to sorafenib has been reported. Numerous clinical trials have been conducted to evaluate a large number of molecularly targeted drugs for treating HCC, but most drugs exhibited less efficacy and/or higher toxicity compared to sorafenib. Therefore, understanding the mechanism(s) underlying sorafenib resistance of cancer cells is highlighted for efficiently treating HCC. This concise review aims to provide an overview of anti-angiogenesis therapy in the management of HCC and to discuss the common mechanisms of resistance to anti-angiogenesis therapies.

Picropodophyllin and sorafenib synergistically suppress the proliferation and motility of hepatocellular carcinoma cells

Resistance is one limitation of sorafenib in the treatment of hepatocellular carcinoma (HCC). Insulin-like growth factor-1 receptor (IGF-1R) is involved in cancer cell proliferation. To assess the potential synergistic antitumor effects of picropodophyllin (PPP), an IGF-1R inhibitor, HLF and PLC/PRL/5, HCC cells were treated with PPP alone or PPP in combination with sorafenib, a multikinase inhibitor. Normal human umbilical vein endothelial cells (HUVECs) were also used to analyze the antiangiogenic effects of the drugs. HCC cells and HUVECs were cultured on 96-well plates, and then treated with PPP, with and without the addition of sorafenib. A 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium inner salt assay and hematoxylin and eosin staining were then performed 48 h later. The HCC cells were also analyzed using scratch assays and hematoxylin and eosin staining after 48 h. The proliferation of HLF, PLC/PRF/5 and HUVEC cells was suppressed by the combination of 0.2 μM PPP and 3 μM sorafenib more effectively than by 10 μM sorafenib alone. The motility of HLF and PLC/PRF/5 cells was also suppressed to a greater extent with the combination of PPP at 0.2 μM and sorafenib at 3 μM than with sorafenib at 10 μM alone. The cells that had been treated with 0.2 μM PPP and 3 μM sorafenib also exhibited pyknotic nuclei, which is characteristic of apoptosis. In conclusion, PPP enhanced sorafenib-mediated suppression of proliferation and motility in HCC cells. Therefore, the combination of PPP and sorafenib may exert antitumor and antiangiogenic effects.

Efficacy and safety of the FOLFOX4 regimen versus doxorubicin in Chinese patients with advanced hepatocellular carcinoma: a subgroup analysis of the EACH study

BACKGROUND

The EACH study assessed the efficacy of oxaliplatin, 5-fluorouracil, and leucovorin (the FOLFOX4 regimen) compared with doxorubicin alone in terms of overall survival (OS), progression-free survival (PFS), and safety in patients with advanced hepatocellular carcinoma (HCC). We present the results of this study in Chinese patients.

METHODS

In a multicenter, open-label, randomized, phase III study (NCT00471965), 371 patients (279 patients from the People's Republic of China) were randomized 1:1 to receive either FOLFOX4 or doxorubicin until disease progression, intolerable toxicity, death, or surgical resection.

RESULTS

Baseline characteristics of the Chinese patients enrolled in the study were similar for the 2 treatment groups and in comparison with the whole EACH cohort. Median OS at the prespecified time point of treatment was 5.7 months with FOLFOX4 and 4.3 months with doxorubicin (hazard ratio [HR]: 0.74; 95% confidence interval [CI]: 0.55-0.98; p = .03). At the end of the follow-up period, median OS was 5.9 months with FOLFOX4 and 4.3 months with doxorubicin (HR: 0.75; 95% CI: 0.58-0.98; p = .03). Median PFS was 2.4 months and 1.7 months in the FOLFOX4 and doxorubicin groups, respectively (HR: 0.55; 95% CI: 0.45-0.78; p = .0002). The response rate (RR) and disease control rate (DCR) were significantly higher in the FOLFOX4 group than in the doxorubicin group (RR: 8.6% vs. 1.4%, p = .006; DCR: 47.1% vs. 26.6%, p = .0004). Hematological toxicity was more frequently reported in the FOLFOX4 group.

CONCLUSION

For Chinese HCC patients enrolled in the EACH study, FOLFOX4 significantly improved the RR and DCR and prolonged survival compared with doxorubicin. Systemic chemotherapy with oxaliplatin-based regimens may play an important role in the treatment of Chinese patients with advanced HCC.

SC-2001 overcomes STAT3-mediated sorafenib resistance through RFX-1/SHP-1 activation in hepatocellular carcinoma

Hepatocellular carcinoma is the fifth most common solid cancer worldwide. Sorafenib, a small multikinase inhibitor, is the only approved therapy for advanced HCC. The clinical benefit of sorafenib is offset by the acquisition of sorafenib resistance. Understanding of the molecular mechanism of STAT3 overexpression in sorafenib resistance is critical if the clinical benefits of this drug are to be improved. In this study, we explored our hypothesis that loss of RFX-1/SHP-1 and further increase of p-STAT3 as a result of sorafenib treatment induces sorafenib resistance as a cytoprotective response effect, thereby, limiting sorafenib sensitivity and efficiency. We found that knockdown of RFX-1 protected HCC cells against sorafenib-induced cell apoptosis and SHP-1 activity was required for the process. SC-2001, a molecule with similar structure to obatoclax, synergistically suppressed tumor growth when used in combination with sorafenib in vitro and overcame sorafenib resistance through up-regulating RFX-1 and SHP-1 resulting in tumor suppression and mediation of dephosphorylation of STAT3. In addition, sustained sorafenib treatment in HCC led to increased p-STAT3 which was a key mediator of sorafenib sensitivity. The combination of SC-2001 and sorafenib strongly inhibited tumor growth in both wild-type and sorafenib-resistant HCC cell bearing xenograft models. These results demonstrate that inactivation of RFX/SHP-1 induced by sustained sorafenib treatment confers sorafenib resistance to HCC through p-STAT3 up-regulation. These effects can be overcome by SC-2001 through RFX-1/SHP-1 dependent p-STAT3 suppression. In conclusion, the use of SC-2001 in combination with sorafenib may constitute a new strategy for HCC therapy.

Synergistic inhibitory effect of hyperbaric oxygen combined with sorafenib on hepatoma cells

OBJECTIVES

Hypoxia is a common phenomenon in solid tumors, associated with chemotherapy and radiotherapy resistance, recurrence and metastasis. Hyperbaric oxygen (HBO) therapy can increase tissue oxygen pressure and content to prevent the resistance, recurrence and metastasis of cancer. Presently, Sorafenib is a first-line drug, targeted for hepatocellular carcinoma (HCC) but effective in only a small portion of patients and can induce hypoxia. The purpose of this study is to investigate the effect of HBO in combination with sorafenib on hepatoma cells.

METHODS

Hepatoma cell lines (BEL-7402 and SK-Hep1) were treated with HBO at 2 atmosphere absolute pressure for 80 min per day or combined with sorafenib or cisplatin. At different time points, cells were tested for cell growth, colony formation, apoptosis, cell cycle and migration. Finally, miRNA from the hepatoma cells was detected by microRNA array and validated by qRT-PCR.

RESULTS

Although HBO, sorafenib or cisplatin alone could inhibit growth of hepatoma cells, HBO combined with sorafenib or cisplatin resulted in much greater synergistic growth inhibition (cell proliferation and colony formation) in hepatoma cells. Similarly, the synergistic effect of HBO and sorafenib on induction of apoptosis was also observed in hepatoma cells. HBO induced G1 arrest in SK-Hep1 not in BEL-7402 cells, but enhanced cell cycle arrest induced by sorafenib in BEL-7402 treated cells. However, HBO had no obvious effect on the migration of hepatoma cells, and microRNA array analysis showed that hepatoma cells with HBO treatment had significantly different microRNA expression profiles from those with blank control.

CONCLUSIONS

We show for the first time that HBO combined with sorafenib results in synergistic growth inhibition and apoptosis in hepatoma cells, suggesting a potential application of HBO combined with sorafenib in HCC patients. Additionally, we also show that HBO significantly altered microRNA expression in hepatoma cells.

Expression and function analysis of mitotic checkpoint genes identifies TTK as a potential therapeutic target for human hepatocellular carcinoma

The mitotic spindle checkpoint (SAC) genes have been considered targets of anticancer therapies. Here, we sought to identify the attractive mitotic spindle checkpoint genes appropriate for human hepatocellular carcinoma (HCC) therapies. Through expression profile analysis of 137 selected mitotic spindle checkpoint genes in the publicly available microarray datasets, we showed that 13 genes were dramatically up-regulated in HCC tissues compared to normal livers and adjacent non-tumor tissues. A role of the 13 genes in proliferation was evaluated by knocking them down via small interfering RNA (siRNA) in HCC cells. As a result, several mitotic spindle checkpoint genes were required for maintaining the proliferation of HCC cells, demonstrated by cell viability assay and soft agar colony formation assay. Then we established sorafenib-resistant sublines of HCC cell lines Huh7 and HepG2. Intriguingly, increased TTK expression was significantly associated with acquired sorafenib-resistance in Huh7, HepG2 cells. More importantly, TTK was observably up-regulated in 46 (86.8%) of 53 HCC specimens. A series of in vitro and in vivo functional experiment assays showed that TTK overexpression promoted cell proliferation, anchor-dependent colony formation and resistance to sorafenib of HCC cells; TTK knockdown restrained cell growth, soft agar colony formation and resistance to sorafenib of HCC cells. Collectively, TTK plays an important role in proliferation and sorafenib resistance and could act as a potential therapeutic target for human hepatocellular carcinoma.

Transferrin targeted core-shell nanomedicine for combinatorial delivery of doxorubicin and sorafenib against hepatocellular carcinoma

Combinatorial drug delivery is an attractive, but challenging requirement of next generation cancer nanomedicines. Here, we report a transferrin-targeted core-shell nanomedicine formed by encapsulating two clinically used single-agent drugs, doxorubicin and sorafenib against liver cancer. Doxorubicin was loaded in poly(vinyl alcohol) nano-core and sorafenib in albumin nano-shell, both formed by a sequential freeze-thaw/coacervation method. While sorafenib from the nano-shell inhibited aberrant oncogenic signaling involved in cell proliferation, doxorubicin from the nano-core evoked DNA intercalation thereby killing >75% of cancer cells. Upon targeting using transferrin ligands, the nanoparticles showed enhanced cellular uptake and synergistic cytotoxicity in ~92% of cells, particularly in iron-deficient microenvironment. Studies using 3D spheroids of liver tumor indicated efficient penetration of targeted core-shell nanoparticles throughout the tissue causing uniform cell killing. Thus, we show that rationally designed core-shell nanoparticles can effectively combine clinically relevant single-agent drugs for exerting synergistic activity against liver cancer.

FROM THE CLINICAL EDITOR

Transferrin-targeted core-shell nanomedicine encapsulating doxorubicin and sorafenib was studied as a drug delivery system against hepatocellular carcinoma, resulting in enhanced and synergistic therapeutic effects, paving the way towards potential future clinical applications of similar techniques.

Inhibition of Akt reverses the acquired resistance to sorafenib by switching protective autophagy to autophagic cell death in hepatocellular carcinoma

Sorafenib is the standard first-line systemic drug for advanced hepatocellular carcinoma (HCC), but the acquired resistance to sorafenib results in limited benefits. Activation of Akt is thought to be responsible for mediating the acquired resistance to sorafenib. The present study aims to examine the underlying mechanism and seek potential strategies to reverse this resistance. Two sorafenib-resistant HCC cell lines, which had been established from human HCC HepG2 and Huh7 cells, were refractory to sorafenib-induced growth inhibition and apoptosis in vitro and in vivo. Sustained exposure to sorafenib activated Akt via the feedback loop of mTOR but independent of protein phosphatase 2A in HCC cells. Autophagy participated in the resistance to sorafenib as inhibition of autophagy reduced the sensitivity of sorafenib-resistant HCC cells to sorafenib, whereas activation of autophagy by rapamycin had the opposite effect. However, rapamycin did not show a synergistic effect with sorafenib to inhibit cell proliferation, while it also activated Akt via a feedback mechanism in sorafenib-resistant HCC cells. Inhibition of Akt reversed the acquired resistance to sorafenib by switching autophagy from a cytoprotective role to a death-promoting mechanism in the sorafenib-resistant HCC cells. Akt inhibition by GDC0068 synergized with sorafenib to suppress the growth of sorafenib-resistant HCC tumors that possessed the sorafenib-resistant feature in vivo. The results have provided evidence for clinical investigation of GDC0068, a novel ATP-competitive pan-Akt inhibitor, as the second-line treatment after the failure of sorafenib-medicated molecular targeted therapy for advanced HCC.

A preclinical evaluation of a novel multikinase inhibitor, SKLB-329, as a therapeutic agent against hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a serious life-threatening malignant disease of liver. Molecular targeted therapies are considered a promising strategy for the treatment of HCC. Sorafenib is the first, and so far the only targeted drug approved by the US Food and Drug Administration (FDA) for clinical therapy of HCC. Despite being effective in some HCC patients, some demerits of sorafenib in the treatment of HCC, such as modest survival benefits, and drug resistance, have also been reported, which highlights the unmet medical need among patients with HCC. Here, we report a novel multikinase inhibitor discovered by us, SKLB-329, which potently inhibits angiogenesis-related kinases including VEGFR1/2/3, and FGFR2, and the Src kinase. SKLB-329 significantly inhibited endothelial cell growth, migration, invasion and tube formation. It showed potent anti-angiogenic activity in a transgenic zebrafish model. Moreover, SKLB-329 could efficiently restrain the proliferation of HCC cells through down-regulation of Src-mediated FAK and Stat3 activity. In vivo, oral administration of SKLB-329 considerably suppressed the tumor growth in HCC xenograft models (HepG2 and SMMC7721) in a dose-dependent manner. In all of the in vitro and in vivo assays of this investigation, sorafenib was used as a positive control, and in most assays SKLB-329 exhibited a higher potency compared with the positive control. In addition, SKLB-329 also bears favorable pharmacokinetic properties. Collectively, the results of preclinical studies presented here demonstrate that SKLB-329 is a promising drug candidate for HCC treatment.