Sorafenib inhibits hypoxia-inducible factor-1α synthesis: implications for antiangiogenic activity in hepatocellular carcinoma

Evodiamine induces apoptosis and promotes hepatocellular carcinoma cell death induced by vorinostat via downregulating HIF-1α under hypoxia

Hypoxia promotes HCC progression and therapy resistance, and there is no systemic treatment for HCC patients after sorafenib resistance. Thus, it is urgent to develop potential therapeutic regimens for HCC patients by targeting hypoxia signaling. In this study, we showed that evodiamine might be a potential therapeutic medicine for HCC by suppressing HIF-1α. In addition, evodiamine could sensitize the anti-HCC effect of vorinostat in HCC cells under hypoxia. Furthermore, evodiamine plus vorinostat accelerated the degradation of HIF-1α in HCC cells under hypoxia. In general, evodiamine might be a potential therapeutic candidate for HCC patients, and evodiamine combining with vorinostat might be an attractive chemotherapy strategy for HCC treatment.

Downregulation of amplified in breast cancer 1 contributes to the anti-tumor effects of sorafenib on human hepatocellular carcinoma

Multi-kinase inhibitor sorafenib represents a major breakthrough in the therapy of advanced hepatocellular carcinoma (HCC). Amplified in breast cancer 1 (AIB1) is frequently overexpressed in human HCC tissues and promotes HCC progression. In this study, we investigated the effects of sorafenib on AIB1 expression and the role of AIB1 in anti-tumor effects of sorafenib. We found that sorafenib downregulated AIB1 protein expression by inhibiting AIB1 mRNA translation through simultaneously blocking eIF4E and mTOR/p70S6K/RP-S6 signaling. Knockdown of AIB1 significantly promoted sorafenib-induced cell death, whereas overexpression of AIB1 substantially diminished sorafenib-induced cell death. Downregulation of AIB1 contributed to sorafenib-induced cell death at least in part through upregulating the levels of reactive oxygen species in HCC cells. In addition, resistance to sorafenib-induced downregulation of AIB1 protein contributes to the acquired resistance of HCC cells to sorafenib-induced cell death. Collectively, our study implicates that AIB1 is a molecular target of sorafenib and downregulation of AIB1 contributes to the anti-tumor effects of sorafenib.

Downregulation and pro-apoptotic effect of hypoxia-inducible factor 2 alpha in hepatocellular carcinoma

The role of HIF-2α in hepatocellular carcinoma (HCC) is unclear. The aim of the present study was to investigate the expression pattern and role of HIF-2α in HCC patients. Immunohistochemical staining and western blotting analyses were applied to detect the protein level of HIF-2α in 206 paired HCC and peritumoral tissues. Kaplan-Meier survival and Cox proportional hazard regression analyses were performed to identify risk factors for overall survival and recurrence-free survival in these patients. The function of HIF-2α was studied in HCC cells and in vivo models. We found that the protein levels of HIF-2α in HCC tissues were lower than in peritumoral tissues, and were negatively correlated with tumor size (P < 0.05). Kaplan-Meier survival and univariate analysis revealed that HCC patients with high HIF-2α protein levels had longer overall survival (P < 0.05). Over-expression of HIF-2α induced apoptosis in HCC cells and increased the levels of pro-apoptotic proteins, Bak, ZBP-89 and PDCD4, whereas the inhibition of HIF-2α expression achieved opposite results. The findings were confirmed in a mouse HCC xenograft model. In conclusion, our study revealed that HIF-2α was decreased and played an anti-tumorigenic role in HCC.

Melatonin enhances sorafenib actions in human hepatocarcinoma cells by inhibiting mTORC1/p70S6K/HIF-1α and hypoxia-mediated mitophagy

The antiangiogenic effects of sustained sorafenib treatment in hepatocellular carcinoma (HCC) lead to the occurrence of hypoxia-mediated drug resistance resulting in low therapy efficiency and negative outcomes. Combined treatments with coadjuvant compounds to target the hypoxia-inducible factor-1α (HIF-1α) represent a promising therapeutic approach through which sorafenib efficiency may be improved. Melatonin is a well-documented oncostatic agent against different cancer types. Here, we evaluated whether melatonin could enhance sorafenib cytotoxicity and overcome the hypoxia-mediated resistance mechanisms in HCC. The pharmacological melatonin concentration (2 mM) potentiated the oncostatic effects of sorafenib (5 μM) on Hep3B cells even under hypoxia. Melatonin downregulated the HIF-1α protein synthesis through the inhibition of the mammalian target of rapamycin complex 1 (mTORC1)/ribosomal protein S6 kinase beta-1 (p70S6K)/ribosomal protein S6 (RP-S6) pathway, although the indole enhanced Akt phosphorylation by the mTORC1/C2 negative feedback. Furthermore, melatonin and sorafenib coadministration reduced the HIF-1α-mitophagy targets expression, impaired autophagosome formation and subsequent mitochondria and lysosomes colocalization. Together, our results indicate that melatonin improves the Hep3B sensitivity to sorafenib, preventing HIF-1α synthesis to block the cytoprotective mitophagy induced by the hypoxic microenvironment, an important element of the multifactorial mechanisms responsible for the chemotherapy failure.

Targeting Hypoxia-Inducible Factors for Antiangiogenic Cancer Therapy

Hypoxia (low O₂) is a pathobiological hallmark of solid cancers, resulting from the imbalance between cellular O₂ consumption and availability. Hypoxic cancer cells (CCs) stimulate blood vessel sprouting (angiogenesis), aimed at restoring O₂ delivery to the expanding tumor masses through the activation of a transcriptional program mediated by hypoxia-inducible factors (HIFs). Here, we review recent data suggesting that the efficacy of antiangiogenic (AA) therapies is limited in some circumstances by HIF-dependent compensatory responses to increased intratumoral hypoxia. In lieu of this evidence, we discuss the potential of targeting HIFs as a strategy to overcome these instances of AA therapy resistance.

New knowledge of the mechanisms of sorafenib resistance in liver cancer

Sorafenib is an oral multikinase inhibitor that suppresses tumor cell proliferation and angiogenesis and promotes tumor cell apoptosis. It was approved by the FDA for the treatment of advanced renal cell carcinoma in 2006, and as a unique target drug for advanced hepatocellular carcinoma (HCC) in 2007. Sorafenib can significantly extend the median survival time of patients but only by 3-5 months. Moreover, it is associated with serious adverse side effects, and drug resistance often develops. Therefore, it is of great importance to explore the mechanisms underlying sorafenib resistance and to develop individualized therapeutic strategies for coping with these problems. Recent studies have revealed that in addition to the primary resistance, several mechanisms are underlying the acquired resistance to sorafenib, such as crosstalk involving PI3K/Akt and JAK-STAT pathways, the activation of hypoxia-inducible pathways, and epithelial-mesenchymal transition. Here, we briefly describe the function of sorafenib, its clinical application, and the molecular mechanisms for drug resistance, especially for HCC patients.

Personalising and targeting antiangiogenic resistance: a complex and multifactorial approach

Pathological angiogenesis involves complex and dynamic interactions between tumour cells and other lineages existing in the microenvironment of the tumour. Preclinical and clinical data suggest that tumours can show dual, different adaptive responses against antiangiogenic agents: one successful adaptation is vascular normalisation, whereas the second adaptation is elicited through vascular trimming and increased hypoxia. These phenomena depend on the type of tumour and the type of agent. The classical approach for investigating acquired resistance against antiangiogenic agents is to identify compensatory signalling pathways emerging in response to VEGF blockade, which has led to the development of highly effective drugs; however, ultimately these drugs fail. Here we review how the dual stromal adaptive patterns determine the mechanisms of escape that go beyond the reprogramming of signal transduction pathways, which obliges us to investigate the tumour as an ecosystem and to develop uni- and multicompartmental models that explain drug resistance involving metabolic and immune reprogramming. We also propose a method for facilitating personalised therapeutic decisions, which uses 18F-fluoromisonidazole-positron emission tomography to monitor the dual stromal response in tumours of individual patients.

Adiponectin promotes VEGF-A-dependent angiogenesis in human chondrosarcoma through PI3K, Akt, mTOR, and HIF-α pathway

Chondrosarcoma is a type of highly malignant tumor with a potent capacity to invade locally and cause distant metastasis. Adiponectin is a protein hormone secreted predominantly by differentiated adipocytes. On the other hand, angiogenesis is a critical step in tumor growth and metastasis. However, the relationship of adiponectin with vascular endothelial growth factor-A (VEGF-A) expression and angiogenesis in human chondrosarcoma is mostly unknown. In this study we first demonstrated that the expression of adiponectin was correlated with tumor stage of human chondrosarcoma tissues. In addition, we also found that adiponectin increased VEGF-A expression in human chondrosarcoma cells and subsequently induced migration and tube formation in human endothelial progenitor cells (EPCs). Adiponectin promoted VEGF-A expression through adiponectin receptor (AdipoR), phosphoinositide 3 kinase (PI3K), Akt, mammalian target of rapamycin (mTOR), and hypoxia-inducible factor-1α (HIF)-1α signaling cascades. Knockdown of adiponectin decreased VEGF-A expression and also abolished chondrosarcoma conditional medium-mediated tube formation in EPCs in vitro as well as angiogenesis effects in the chick chorioallantoic membrane and Matrigel plug nude mice model in vivo. Therefore, adiponectin is crucial for tumor angiogenesis and growth, which may represent a novel target for anti-angiogenic therapy in human chondrosarcoma.

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.

Hypoxia induces myeloid-derived suppressor cell recruitment to hepatocellular carcinoma through chemokine (C-C motif) ligand 26

A population of stromal cells, myeloid-derived suppressor cells (MDSCs), is present in tumors. Though studies have gradually revealed the protumorigenic functions of MDSCs, the molecular mechanisms guiding MDSC recruitment remain largely elusive. Hypoxia, O2 deprivation, is an important factor in the tumor microenvironment of solid cancers, whose growth often exceeds the growth of functional blood vessels. Here, using hepatocellular carcinoma as the cancer model, we show that hypoxia is an important driver of MDSC recruitment. We observed that MDSCs preferentially infiltrate into hypoxic regions in human hepatocellular carcinoma tissues and that hypoxia-induced MDSC infiltration is dependent on hypoxia-inducible factors. We further found that hypoxia-inducible factors activate the transcription of chemokine (C-C motif) ligand 26 in cancer cells to recruit chemokine (C-X3-C motif) receptor 1-expressing MDSCs to the primary tumor. Knockdown of chemokine (C-C motif) ligand 26 in cancer cells profoundly reduces MDSC recruitment, angiogenesis, and tumor growth. Therapeutically, blockade of chemokine (C-C motif) ligand 26 production in cancer cells by the hypoxia-inducible factor inhibitor digoxin or blockade of chemokine (C-X3-C motif) receptor 1 in MDSCs by chemokine (C-X3-C motif) receptor 1 neutralizing antibody could substantially suppress MDSC recruitment and tumor growth.

CONCLUSION

This study unprecedentedly reveals a novel molecular mechanism by which cancer cells direct MDSC homing to primary tumor and suggests that targeting MDSC recruitment represents an attractive therapeutic approach against solid cancers. (Hepatology 2016;64:797-813).

NDRG1 promotes growth of hepatocellular carcinoma cells by directly interacting with GSK-3β and Nur77 to prevent β-catenin degradation

The N-myc downstream regulated gene 1 (NDRG1) is significantly associated with advanced tumor stages and poor survival of hepatocellular carcinoma (HCC), thereby implicating it as a potential target for HCC treatment. We aim to further understand its biological roles in hepatocarcinogenesis, as a means to exploit it for therapeutic purposes. By screening using the ProtoArray® Human Protein Microarrays, we identified glycogen synthase kinase 3β (GSK-3β) and the orphan nuclear receptor (Nur77) as potential interaction partners of NDRG1. These interactions were confirmed in HCC cell lines in vitro by co-immunoprecipitation; and co-localizations of NDRG1 with GSK-3β and Nur77 were observed by immunofluorescence staining. Additionally, high levels of NDRG1 competitively bind to GSK-3β and Nur77 to allow β-catenin to escape degradation, with consequent elevated levels of downstream oncogenic genes. In vivo, we consistently observed that NDRG1 suppression in HCC xenografts decreased β-catenin levels and its downstream target Cyclin D1, with concomitant tumor growth inhibition. Clinically, the over-expression of NDRG1 in HCC patient samples is positively correlated with GSK-3β-9ser (|”‚ R | = 0.28, p = 0.01), Nur77 (|”‚ R | = 0.42, p < 0.001), and β-catenin (| R |= 0.32, p = 0.003) expressions. In conclusion, we identified GSK-3β and Nur77 as novel interaction partners of NDRG1. These protein-protein interactions regulate the turnover of β-catenin and subsequent downstream signaling mediated by β-catenin in HCC cells, and provides potential targets for future therapeutic interventions.

Therapeutic application of anti-angiogenic nanomaterials in cancers

Angiogenesis, the formation of new blood vessels from pre-existing vasculature, plays a vital role in physiological and pathological processes (embryonic development, wound healing, tumor growth and metastasis). The overall balance of angiogenesis inside the human body is maintained by pro- and anti-angiogenic signals. The processes by which drugs inhibit angiogenesis as well as tumor growth are called the anti-angiogenesis technique, a most promising cancer treatment strategy. Over the last couple of decades, scientists have been developing angiogenesis inhibitors for the treatment of cancers. However, conventional anti-angiogenic therapy has several limitations including drug resistance that can create problems for a successful therapeutic strategy. Therefore, a new comprehensive treatment strategy using antiangiogenic agents for the treatment of cancer is urgently needed. Recently researchers have been developing and designing several nanoparticles that show anti-angiogenic properties. These nanomedicines could be useful as an alternative strategy for the treatment of various cancers using anti-angiogenic therapy. In this review article, we critically focus on the potential application of anti-angiogenic nanomaterial and nanoparticle based drug/siRNA/peptide delivery systems in cancer therapeutics. We also discuss the basic and clinical perspectives of anti-angiogenesis therapy, highlighting its importance in tumor angiogenesis, current status and future prospects and challenges.

Distinguished prognosis after hepatectomy of HBV-related hepatocellular carcinoma with or without cirrhosis: a long-term follow-up analysis

BACKGROUND

Conflicting results have often been observed for the prognosis of hepatocellular carcinoma (HCC) patients, but few studies have attempted to explore the reasons for the conflicting results. We aimed to distinguish the prognosis of patients with HCC with cirrhosis (HCC-C) and that of patients with HCC without cirrhosis (HCC-NC).

METHODS

Patients with hepatitis B virus (HBV)-associated HCC treated by curative liver resection at a single institution between 1995 and 2013 were retrospectively evaluated. Kaplan-Meier and multivariate analyses were performed to identify risk factors, including tumor-related factors, hypoxia-inducible factor 1α expression, HBV X protein (HBx) expression, and HBx double mutations for overall survival and recurrence-free survival in these patients.

RESULTS

The long-term prognosis of HCC-NC patients is better than that of HCC-C patients. Male sex, poor differentiation, preoperative serum alanine aminotransferase level greater than 80 IU/L, and α-fetoprotein level greater than 400 ng/mL were risk factors for overall survival among HCC-NC patients but not among HCC-C patients, and age greater than 50 years was associated with poor overall survival only in cirrhotic patients. HCC-C patients benefit more from antiviral therapy following curative hepatectomy than do HCC-NC patients. The clinical value of the biomarkers hypoxia-inducible factor 1α, HBx, and HBx double mutations for predicting HCC prognosis was significantly different between these two groups.

CONCLUSIONS

There were differences in tumor-related prognostic factors, effectiveness of the antiviral therapy after hepatectomy, and biomarkers between HCC-C and HCC-NC patients, indicating that subgroup analysis of the prognostic factors may result in better management of HCC and that HCC patients, especially those with liver cirrhosis, should be given antiviral therapy.

Modulation of Autophagy by Sorafenib: Effects on Treatment Response

The multikinase inhibitor sorafenib is, at present, the only drug approved for the treatment of hepatocellular carcinoma (HCC), one of the most lethal types of cancer worldwide. However, the increase in the number of sorafenib tumor resistant cells reduces efficiency. A better knowledge of the intracellular mechanism of the drug leading to reduced cell survival could help to improve the benefits of sorafenib therapy. Autophagy is a bulk cellular degradation process activated in a broad range of stress situations, which allows cells to degrade misfolded proteins or dysfunctional organelles. This cellular route can induce survival or death, depending on cell status and media signals. Sorafenib, alone or in combination with other drugs is able to induce autophagy, but cell response to the drug depends on the complex integrative crosstalk of different intracellular signals. In cancerous cells, autophagy can be regulated by different cellular pathways (Akt-related mammalian target of rapamycin (mTOR) inhibition, 5′ AMP-activated protein kinase (AMPK) induction, dissociation of B-cell lymphoma 2 (Bcl-2) family proteins from Beclin-1), or effects of some miRNAs. Inhibition of mTOR signaling by sorafenib and diminished interaction between Beclin-1 and myeloid cell leukemia 1 (Mcl-1) have been related to induction of autophagy in HCC. Furthermore, changes in some miRNAs, such as miR-30α, are able to modulate autophagy and modify sensitivity in sorafenib-resistant cells. However, although AMPK phosphorylation by sorafenib seems to play a role in the antiproliferative action of the drug, it does not relate with modulation of autophagy. In this review, we present an updated overview of the effects of sorafenib on autophagy and its related activation pathways, analyzing in detail the involvement of autophagy on sorafenib sensitivity and resistance.

Transarterial Chemoembolization Using Sorafenib in a Rabbit VX2 Liver Tumor Model: Pharmacokinetics and Antitumor Effect

PURPOSE

To investigate feasibility, safety, and effect of transarterial chemoembolization using sorafenib on degree of tumor necrosis in a rabbit VX2 liver tumor model.

MATERIALS AND METHODS

New Zealand White rabbits (n = 20) with a VX2 tumor were divided into two groups; one group was treated with hepatic arterial administration of 0.5 mL ethiodized oil alone (Lipiodol; Guerbet, Aulnay-sous-Bois, France) (transarterial embolization with Lipiodol [TAE-L] group), and one group was treated with 0.5 mL ethiodized oil plus 10 mg sorafenib (transarterial embolization with sorafenib [TAE-S] group). Liquid chromatography tandem mass spectrometry was used to measure sorafenib concentration in peripheral blood and tissue. Hepatic enzymes, vascular endothelial growth factor (VEGF), and hypoxia-inducible factor 1α (HIF-1α) were measured at 0, 24, and 72 hours after treatment. Histopathologic examination was performed to evaluate extent of tumor necrosis and normal parenchymal damage.

RESULTS

Serum sorafenib concentration peaked at 2 hours after treatment. The mean tissue concentration was 406.8 times greater than the serum concentration. Aspartate aminotransferase and alanine aminotransferase levels were significantly elevated in the TAE-S group at 24 hours after treatment. Serum VEGF and HIF-1α concentrations were not significantly different between the TAE-L and TAE-S groups. Hepatic parenchymal damage was more severe in the TAE-S group. Mean fraction of tumor necrosis after treatment was significantly greater in the TAE-S group.

CONCLUSIONS

Transarterial chemoembolization using sorafenib resulted in a high intrahepatic concentration of sorafenib. The degree of tumor necrosis was significantly greater in the TAE-S group compared with the TAE-L group, but more severe toxicity of normal liver tissue also occurred.

Hepatitis B virus X protein induces expression of alpha-fetoprotein and activates PI3K/mTOR signaling pathway in liver cells

The hepatitis B virus (HBV)-X protein (HBx) induces malignant transformation of liver cells, and elevated expression of alpha-fetoprotein (AFP) is a significant biomarker of hepatocarcinogenesis. However, the role of AFP in HBV-related hepatocarcinogenesis is unclear. In this study, we investigated the regulatory impact of AFP expression on HBx-mediated malignant transformation of human hepatocytes. We found that HBV induced the expression of AFP before that of oncogenes, e.g., Src, Ras and chemokine (C-X-C motif) receptor 4 (CXCR4), and AFP activated protein kinase B (AKT) and mammalian target of rapamycin (mTOR) in HBV-related HCC tissues and in human liver cells transfected with HBx. Cytoplasmic AFP interacted with and inhibited phosphatase and tensin homolog deleted on chromosome 10 (PTEN), activating the phosphatidylinositol 3-kinase (PI3K)/AKT signaling pathway and promoting mTOR-mediated stimulation of the transcription factor hypoxia inducible factor-1α (HIF-1α), and therefore led to the activation of the promoters of Src, CXCR4, and Ras genes. On the contrary, reduced expression of AFP by siRNA resulted in the repression of p-mTOR, pAKT, Src, CXCR4, and Ras in human malignant liver cells. Taken together, for the first time our study indicates that HBx-induced AFP expression critically promote malignant transformation in liver cells through the activation of PI3K/mTOR signaling.

Signal transducer and activator of transcription 3-mediated CD133 up-regulation contributes to promotion of hepatocellular carcinoma

Enhanced expression of the cancer stem cell (CSC) marker, CD133, is closely associated with a higher rate of tumor formation and poor prognosis in hepatocellular carcinoma (HCC) patients. Despite its clinical significance, the molecular mechanism underlying the deregulation of CD133 during tumor progression remains to be clarified. Here, we report on a novel mechanism by which interleukin-6/signal transducer and activator of transcription 3 (IL-6/STAT3) signaling up-regulates expression of CD133 and promotes HCC progression. STAT3 activated by IL-6 rapidly bound to CD133 promoter and increased protein levels of CD133 in HCC cells. Reversely, in hypoxic conditions, RNA interference silencing of STAT3 resulted in decrease of CD133 levels, even in the presence of IL-6, with a concomitant decrease of hypoxia-inducible factor 1 alpha (HIF-1α) expression. Active STAT3 interacted with nuclear factor kappa B (NF-κB) p65 subunit to positively regulate the transcription of HIF-1α providing a mechanistic explanation on how those three oncogenes work together to increase the activity of CD133 in a hypoxic liver microenvironment. Activation of STAT3 and its consequent induction of HIF-1α and CD133 expression were not observed in Toll-like receptor 4/IL-6 double-knockout mice. Long-term silencing of CD133 by a lentiviral-based approach inhibited cancer cell-cycle progression and suppressed in vivo tumorigenicity by down-regulating expression of cytokinesis-related genes, such as TACC1, ACF7, and CKAP5. We also found that sorafenib and STAT3 inhibitor nifuroxazide inhibit HCC xenograft formation by blocking activation of STAT3 and expression of CD133 and HIF-1α proteins.

CONCLUSION

IL-6/STAT3 signaling induces expression of CD133 through functional cooperation with NF-κB and HIF-1α during liver carcinogenesis. Targeting STAT3-mediated CD133 up-regulation may represent a novel, effective treatment by eradicating the liver tumor microenvironment.

Molecular Profiling-Selected Therapy for Treatment of Advanced Pancreaticobiliary Cancer: A Retrospective Multicenter Study

This multicenter cohort study assessed the impact of molecular profiling (MP) on advanced pancreaticobiliary cancer (PBC). The study included 30 patients treated with MP-guided therapy after failing ≥ 1 therapy for advanced PBC. Treatment was considered as having benefit for the patient if the ratio between the longest progression-free survival (PFS) on MP-guided therapy and the PFS on the last therapy before MP was ≥ 1.3. The null hypothesis was that ≤ 15% of patients gain such benefit. Overall, ≥ 1 actionable (i.e., predictive of response to specific therapies) biomarker was identified/patient. Immunohistochemistry (the most commonly used method for guiding treatment decisions) identified 1-6 (median: 4) actionable biomarkers per patient. After MP, patients received 1-4 (median: 1) regimens/patient (most commonly, FOLFIRI/XELIRI). In a decision-impact analysis, of the 27 patients for whom treatment decisions before MP were available, 74.1% experienced a treatment decision change in the first line after MP. Twenty-four patients were evaluable for clinical outcome analysis; in 37.5%, the PFS ratio was ≥ 1.3. In one-sided exact binomial test versus the null hypothesis, P = 0.0015; therefore, the null hypothesis was rejected. In conclusion, our analysis demonstrated the feasibility, clinical decision impact, and potential clinical benefits of MP-guided therapy in advanced PBC.

Gene Expression Signatures Predictive of Bevacizumab/Erlotinib Therapeutic Benefit in Advanced Nonsquamous Non-Small Cell Lung Cancer Patients (SAKK 19/05 trial)

PURPOSE

We aimed to identify gene expression signatures associated with angiogenesis and hypoxia pathways with predictive value for treatment response to bevacizumab/erlotinib (BE) of nonsquamous advanced non-small cell lung cancer (NSCLC) patients.

EXPERIMENTAL DESIGN

Whole-genome gene expression profiling was performed on 42 biopsy samples (from SAKK 19/05 trial) using Affymetrix exon arrays, and associations with the following endpoints: time-to-progression (TTP) under therapy, tumor-shrinkage (TS), and overall survival (OS) were investigated. Next, we performed gene set enrichment analyses using genes associated with the angiogenic process and hypoxia response to evaluate their predictive value for patients' outcome.

RESULTS

Our analysis revealed that both the angiogenic and hypoxia response signatures were enriched within the genes predictive of BE response, TS, and OS. Higher gene expression levels (GEL) of the 10-gene angiogenesis-associated signature and lower levels of the 10-gene hypoxia response signature predicted improved TTP under BE, 7.1 months versus 2.1 months for low versus high-risk patients (P = 0.005), and median TTP 6.9 months versus 2.9 months (P = 0.016), respectively. The hypoxia response signature associated with higher TS at 12 weeks and improved OS (17.8 months vs. 9.9 months for low vs. high-risk patients, P = 0.001).

CONCLUSIONS

We were able to identify gene expression signatures derived from the angiogenesis and hypoxia response pathways with predictive value for clinical outcome in advanced nonsquamous NSCLC patients. This could lead to the identification of clinically relevant biomarkers, which will allow for selecting the subset of patients who benefit from the treatment and predict drug response.

Pre-clinical activity of PR-104 as monotherapy and in combination with sorafenib in hepatocellular carcinoma

PR-104 is a clinical stage bioreductive prodrug that is converted in vivo to its cognate alcohol, PR-104A. This dinitrobenzamide mustard is reduced to activated DNA cross-linking metabolites (hydroxylamine PR-104H and amine PR-104M) under hypoxia by one-electron reductases and independently of hypoxia by the 2-electron reductase aldo-keto reductase 1C3 (AKR1C3). High expression of AKR1C3, along with extensive hypoxia, suggested the potential of PR-104 for treatment of hepatocellular carcinoma (HCC). However, a phase IB trial with sorafenib demonstrated significant toxicity that was ascribed in part to reduced PR-104A clearance, likely reflecting compromised glucuronidation in patients with advanced HCC. Here, we evaluate the activity of PR-104 in HCC xenografts (HepG2, PLC/PRF/5, SNU-398, Hep3B) in mice, which do not significantly glucuronidate PR-104A. Cell line differences in sensitivity to PR-104A in vitro under aerobic conditions could be accounted for by differences in both expression of AKR1C3 (high in HepG2 and PLC/PRF/5) and sensitivity to the major active metabolite PR-104H, to which PLC/PRF/5 was relatively resistant, while hypoxic selectivity of PR-104A cytotoxicity and reductive metabolism was greatest in the low-AKR1C3 SNU-398 and Hep3B lines. Expression of AKR1C3 in HepG2 and PLC/PRF/5 xenografts was in the range seen in 21 human HCC specimens. PR-104 monotherapy elicited significant reductions in growth of Hep3B and HepG2 xenografts, and the combination with sorafenib was significantly active in all 4 xenograft models. The results suggest that better-tolerated analogs of PR-104, without a glucuronidation liability, may have the potential to exploit AKR1C3 and/or hypoxia in HCC in humans.

MiR-338-3p inhibits hepatocarcinoma cells and sensitizes these cells to sorafenib by targeting hypoxia-induced factor 1α

Hypoxia is a common feature of solid tumors and an important contributor to anti-tumor drug resistance. Hypoxia inducible factor-1 (HIF-1) is one of the key mediators of the hypoxia signaling pathway, and was recently proven to be required for sorafenib resistance in hepatocarcinoma (HCC). MicroRNAs have emerged as important posttranslational regulators in HCC. It was reported that miR-338-3p levels are associated with clinical aggressiveness of HCC. However, the roles of miR-338-3p in HCC disease and resistance to its therapeutic drugs are unknown. In this study, we found that miR-338-3p was frequently down-regulated in 14 HCC clinical samples and five cell lines. Overexpression of miR-338-3p inhibited HIF-1α 3'-UTR luciferase activity and HIF-1α protein levels in HepG2, SMMC-7721, and Huh7 cells. miR-338-3p significantly reduced cell viability and induced cell apoptosis of HCC cells. Additionally, HIF-1α overexpression rescued and HIF-1α knock-down abrogated the anti-HCC activity of miR-338-3p. Furthermore, miR-338-3p sensitized HCC cells to sorafenib in vitro and in a HCC subcutaneous nude mice tumor model by inhibiting HIF-1α. Collectively, miR-338-3p inhibits HCC tumor growth and sensitizes HCC cells to sorafenib by down-regulating HIF-1α. Our data indicate that miR-338-3p could be a potential candidate for HCC therapeutics.

2-Methoxyestradiol synergizes with sorafenib to suppress hepatocellular carcinoma by simultaneously dysregulating hypoxia-inducible factor-1 and -2

Sorafenib is the approved systemic drug of choice for advanced hepatocellular carcinoma (HCC), but has demonstrated limited benefits because of drug resistance. 2-Methoxyestradiol (2ME2) has been shown to be a promising anticancer drug against various types of cancers and acts by dysregulating hypoxia-inducible factor (HIF)-1. Hypoxic cancer cells are extremely resistant to therapies since they elicit strong survival ability due to the cellular adaptive response to hypoxia, which is controlled by HIF-1 and HIF-2. The present study has demonstrated that sorafenib downregulated the expression of HIF-1α, making the hypoxic response switch from HIF-1α- to HIF-2α-dependent pathways, resulting in upregulation of HIF-2α, which contributes to the insensitivity of hypoxic HCC cells to sorafenib. HIF-2α played a dominant role in regulating VEGF, thus sorafenib in turn increased the expression of VEGF (a downstream molecule of both HIF-1 and HIF-2) and cyclin D1 (a downstream molecule of HIF-2), but reduced the expression of LDHA (a downstream molecule of HIF-1), in hypoxic HCC cells. 2ME2 significantly reduced the expression of both HIF-1α and HIF-2α, and their downstream molecules, VEGF, LDHA and cyclin D1, rendering hypoxic HCC cells to increased sensitivity to 2ME2. 2ME2 also inhibited the nuclear translocation of HIF-1α and HIF-2α proteins, but had no effect on their mRNA expression. 2M2 synergized with sorafenib to suppress the proliferation and induction of apoptosis of HCC cells in vitro and in vivo, and inhibited tumoral angiogenesis. These results indicate that 2ME2 given in combination with sorafenib acts synergistically for treating HCC.

Brain-derived neurotrophic factor increases vascular endothelial growth factor expression and enhances angiogenesis in human chondrosarcoma cells

Chondrosarcomas are a type of primary malignant bone cancer, with a potent capacity for local invasion and distant metastasis. Brain-derived neurotrophic factor (BDNF) is commonly upregulated during neurogenesis. The aim of the present study was to examine the mechanism involved in BDNF-mediated vascular endothelial growth factor (VEGF) expression and angiogenesis in human chondrosarcoma cells. Here, we knocked down BDNF expression in chondrosarcoma cells and assessed their capacity to control VEGF expression and angiogenesis in vitro and in vivo. We found knockdown of BDNF decreased VEGF expression and abolished chondrosarcoma conditional medium-mediated angiogenesis in vitro as well as angiogenesis effects in vivo in the chick chorioallantoic membrane and Matrigel plug nude mouse models. In addition, in the xenograft tumor angiogenesis model, the knockdown of BDNF significantly reduced tumor growth and tumor-associated angiogenesis. BDNF increased VEGF expression and angiogenesis through the TrkB receptor, PLCγ, PKCα, and the HIF-1α signaling pathway. Finally, we analyzed samples from chondrosarcoma patients by immunohistochemical staining. The expression of BDNF and VEGF protein in 56 chondrosarcoma patients was significantly higher than in normal cartilage. In addition, the high level of BDNF expression correlated strongly with VEGF expression and tumor stage. Taken together, our results indicate that BDNF increases VEGF expression and enhances angiogenesis through a signal transduction pathway that involves the TrkB receptor, PLCγ, PKCα, and the HIF-1α. Therefore, BDNF may represent a novel target for anti-angiogenic therapy for human chondrosarcoma.

The role of hypoxia inducible factor-1 in hepatocellular carcinoma

Hypoxia is a common feature of many solid tumors, including hepatocellular carcinoma (HCC). Hypoxia can promote tumor progression and induce radiation and chemotherapy resistance. As one of the major mediators of hypoxic response, hypoxia inducible factor-1 (HIF-1) has been shown to activate hypoxia-responsive genes, which are involved in multiple aspects of tumorigenesis and cancer progression, including proliferation, metabolism, angiogenesis, invasion, metastasis and therapy resistance. It has been demonstrated that a high level of HIF-1 in the HCC microenvironment leads to enhanced proliferation and survival of HCC cells. Accordingly, overexpression, of HIF-1 is associated with poor prognosis in HCC. In this review, we described the mechanism by which HIF-1 is regulated and how HIF-1 mediates the biological effects of hypoxia in tissues. We also summarized the latest findings concerning the role of HIF-1 in the development of HCC, which could shed light on new therapeutic approaches for the treatment of HCC.

Nintedanib (BIBF-1120) inhibits hepatocellular carcinoma growth independent of angiokinase activity

BACKGROUND & AIMS

Nintedanib, a triple angiokinase inhibitor, is currently being evaluated against advanced HCC in phase I/II clinical trials. Here, we report the underlying molecular mechanism by which nintedanib (BIBF-1120) induces an anti-HCC effect.

METHODS

To further elucidate whether the effect of nintedanib on SHP-1 is dependent on its angiokinase inhibition activity, we developed a novel kinase-independent derivative of nintedanib, ΔN. HCC cell lines were treated with nintedanib or its derivative (ΔN) and apoptosis, signal transduction, and phosphatase activity were analyzed. Purified SHP-1 proteins or HCC cells expressing deletion N-SH2 domain or D61A point mutants were used to investigate the potential effect of nintedanib on SHP-1. In vivo efficacy was determined in nude mice with HCC subcutaneous xenografts (n⩾8 mice).

RESULTS

Nintedanib induced anti-proliferation in HCC cell lines by targeting STAT3. Ectopic STAT3 abolished nintedanib-mediated apoptosis in HCC cells. Nintedanib further activated SHP-1 in purified SHP-1 proteins suggesting that nintedanib directly affects SHP-1 for STAT3 inhibition. HCC cells or recombinant SHP-1 proteins expressing deletion of N-SH2 domain or D61A mutants restored the activity of nintedanib suggesting that the auto-inhibition structure of SHP-1 was relieved by nintedanib. Although ΔN only retained the backbone of nintedanib without kinase activity, ΔN still induced substantial anti-HCC activity in vitro and in vivo by targeting STAT3.

CONCLUSIONS

Nintedanib induced significant anti-HCC activity independent of angiokinase inhibition activity in a preclinical HCC model by relieving autoinhibition of SHP-1. Our findings provide new mechanistic insight into the inhibition of HCC growth by nintedanib.

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.

Sorafenib in advanced hepatocellular carcinoma: current status and future perspectives

The approval of sorafenib, a multikinase inhibitor targeting primarily Raf kinase and the vascular endothelial growth factor receptor, in 2007 for treating advanced hepatocellular carcinoma (HCC) has generated considerable enthusiasm in drug development for this difficult-to-treat disease. However, because several randomized Phase III studies testing new multikinase inhibitors failed, sorafenib remains the standard of first-line systemic therapy for patients with advanced HCC. Field practice studies worldwide have suggested that in daily practice, physicians are adopting either a preemptive dose modification or a ramp-up strategy to improve the compliance of their patients. In addition, accumulating data have suggested that patients with Child-Pugh class B liver function can tolerate sorafenib as well as patients with Child-Pugh class A liver function, although the actual benefit of sorafenib in patients with Child-Pugh class B liver function has yet to be confirmed. Whether sorafenib can be used as an adjunctive therapy to improve the outcomes of intermediate-stage HCC patients treated with transcatheter arterial chemoembolization or early-stage HCC patients after curative therapies is being investigated in several ongoing randomized Phase III studies. An increasing number of studies have reported that sorafenib exerts "off-target" effects, including the modulation of signaling pathways other than Raf/MEK/ERK pathway, nonapoptotic cell death mechanisms, and even immune modulation. Finally, although sorafenib in combination with chemotherapy or other targeted therapies has the potential to improve therapeutic efficacy in treating HCC, it also increases toxicity. Additional clinical studies are warranted to determine useful sorafenib-based combinations for the treatment of advanced HCC.

Evaluation of the impact of transient interruption of antiangiogenic treatment using ultrasound-based techniques in a murine model of hepatocellular carcinoma

Background

Development of escape pathways from antiangiogenic treatments was reported to be associated with enhanced tumor aggressiveness and rebound effect was suggested after treatment stop. Aim of the study was to evaluate tumor response simulating different conditions of administration of antiangiogenic treatment (transient or definitive treatment stop) in a mouse model of hepatocellular carcinoma.

Methods

Subcutaneous tumors were created by inoculating 5×10⁶ Huh7 cells into the right flank of 14 nude mice. When tumor size reached 5–10 mm, mice were divided in 3 groups: group 1 was treated with placebo, group 2 was treated with sorafenib (62 mg/kg via gavage) but temporarily suspended from day +5 to +9, whereas in group 3 sorafenib was definitively stopped at day +5. At day +13 all mice were sacrificed, collecting masses for Western-Blot analyses. Volume was calculated with B-mode ultrasonography at day 0, +5, +9, +11 and +13. VEGFR2-targeted contrast-enhanced ultrasound using BR55 (Bracco Imaging) was performed at day +5 and +13 and elastonosography (Esaote) at day +9 and +11 to assess tumor stiffness.

Results

Median growth percentage delta at day +13 versus day 0 was 197% (115–329) in group 1, 81% (48–144) in group 2 and 111% (27–167) in group 3. Median growth delta at day +13 with respect to day +5 was 79% (48–127), 37% (−14128) and 81% (15–87) in groups 1, 2 and 3, respectively. Quantification of targeted-CEUS at day +13 showed higher values in group 3 (509 Arbitrary Units AI, range 293–652) than group 1 (275 AI, range 191–494) and group 2 (181 AI, range 63–318) (p = 0.033). Western-Blot analysis demonstrated higher VEGFR2 expression in group 3 with respect to group 1 and 2.

Conclusions

A transient interruption of antiangiogenic treatment does not impede restoration of tumor response, while a definitive interruption tends to stimulate a rebound of angiogenesis to higher level than without treatment.

Celastrol inhibits the HIF-1α pathway by inhibition of mTOR/p70S6K/eIF4E and ERK1/2 phosphorylation in human hepatoma cells

Hypoxia-inducible factor-1 (HIF-1) is the central mediator of cellular responses to low oxygen and vital to many aspects of cancer biology. In a search for HIF-1 inhibitors, we identified celastrol as an inhibitor of HIF-1 activation from Tripterygium wilfordii. In the present study, we demonstrated the effect of celastrol on HIF-1 activation. Celastrol showed a potent inhibitory activity against HIF-1 activation induced by hypoxia in various human cancer cell lines. This compound markedly decreased the hypoxia-induced accumulation of HIF-1α protein dose-dependently, whereas it did not affect the expressions of HIF-1β and topoisomerase-I (topo‑I). Furthermore, celastrol prevented hypoxia-induced expression of HIF-1 target genes for vascular endothelial growth factor (VEGF) and erythropoietin (EPO). Further analysis revealed that celastrol inhibited HIF-1α protein synthesis, without affecting the expression level of HIF-1α mRNA or degradation of HIF-1α protein. Markedly, we found that suppression of HIF-1α accumulation by celastrol correlated with strong dephosphorylation of mammalian target of rapamycin (mTOR) and its effectors, ribosomal protein S6 kinase (p70S6K) and eukaryotic initiation factor 4E (eIF4E) and extracellular signal-regulated kinase (ERK), pathways known to regulate HIF-1α expression at the translational level. In vivo studies further confirmed the inhibitory effect of celastrol on the expression of HIF-1α proteins, leading to a decreased growth of Hep3B cells in a xenograft tumor model. Our data suggested that celastrol is an effective inhibitor of HIF-1 and provide new perspectives into the mechanism of its anticancer activity.

Molecular responses to hypoxia-inducible factor 1α and beyond

Cellular response to changes in oxygen tension during normal development or pathologic processes is, in part, regulated by hypoxia-inducible factor (HIF), an oxygen-sensitive transcription factor. HIF activity is primarily controlled through post-translational modifications and stabilization of HIF-1α and HIF-2α proteins and is regulated by a number of cellular pathways involving both oxygen-dependent and -independent mechanisms. Stabilization of HIF-1α activates transcription of genes that participate in key pathways in carcinogenesis, such as angiogenesis, dedifferentiation, and invasion. Since its discovery more than two decades ago, HIF-1α has become a hot topic in molecular research and has been implicated not only in disease pathology but also in prognosis. In this review, we will focus on recent insights into HIF-1α regulation, function, and gene expression. We will also discuss emerging data on the involvement of HIF in cancer prognosis and therapeutic interventions.

Upregulation of HIF-2α induced by sorafenib contributes to the resistance by activating the TGF-α/EGFR pathway in hepatocellular carcinoma cells

Sorafenib, the first-line systemic drug for advanced hepatocellular carcinoma (HCC), has demonstrated limited benefits with very low response rates. Thus it is essential to investigate the underlying mechanisms for the resistance to sorafenib and seek potential strategy to enhance its efficacy. Hypoxic cells inside solid tumors are extremely resistant to therapies as their survival ability is increased due to the cellular adaptive response to hypoxia, which is controlled by hypoxia-inducible factor (HIF)-1 and HIF-2. Sorafenib inhibits HIF-1α synthesis, making the hypoxic response switch from HIF-1α- to HIF-2α-dependent pathways and providing a mechanism for more aggressive growth of tumors. The present study has demonstrated that upregulation of HIF-2α induced by sorafenib contributes to the resistance of hypoxic HCC cells by activating the transforming growth factor (TGF)-α/epidermal growth factor receptor (EGFR) pathway. Blocking the TGF-α/EGFR pathway by gefitinib, a specific EGFR inhibitor, reduced the activation of STAT (signal transducer and activator of transcription) 3, AKT and ERK (extracellular signal-regulated kinase), and synergized with sorafenib to inhibit proliferation and induce apoptosis of hypoxic HCC cells. Transfection of HIF-2α siRNA into HCC cells downregulated the expression of VEGF (vascular endothelial growth factor), cyclin D1, HIF-2α and TGF-α, and inhibited the activation of EGFR. HIF-2α siRNA inhibited the proliferation and promoted the apoptosis of HCC cells in vitro, and synergized with sorafenib to suppress the growth of HCC tumors in vivo. The results indicate that targeting HIF-2α-mediated activation of the TGF-α/EGFR pathway warrants further investigation as a potential strategy to enhance the efficacy of sorafenib for treating HCC.

ROS-mediated JNK/p38-MAPK activation regulates Bax translocation in Sorafenib-induced apoptosis of EBV-transformed B cells

Sorafenib (SRF) is a multi-kinase inhibitor that has been shown to have antitumor activity against several types of cancers, but the effect of SRF on EBV-transformed B cells is unknown. We report that SRF can induce the apoptosis of EBV-transformed B cells through JNK/p38-MAPK activation. SRF triggered the generation of reactive oxygen species (ROS), translocation of Bax into the mitochondria, disruption of mitochondrial membrane potential, activation of caspase-9, caspase-3 and PARP, and subsequent apoptosis. Moreover, we found that SRF exposure activated the phosphorylation of JNK and p38-MAPK and suppressed the phosphorylation of PI3K-p85 and Akt. N-acetyl-l-cysteine (NAC) inhibited the activation of JNK and p38-MAPK. SP600125 and SB203580 blocked apoptosis and mitochondrial membrane disruption but did not affect ROS production after SRF treatment. These findings provide novel insights into the molecular mechanisms driving SRF-mediated cell death and suggest that SRF could be a potential therapeutic drug for the treatment of EBV-related malignant diseases.

Roles of HIF-1 in hepatocellular carcinoma

Hypoxia inducible factor-1 (HIF-1) is a key regulator of the cellular response to hypoxia. Since cell growth is out of control in hepatocellular carcinoma (HCC), HIF-1 activity is significantly enhanced in HCC to help cells adapt to the hypoxic microenvironment. HIF-1 plays a critical role in the occurrence and development of HCC through activating the target genes that participate in the regulation of cell proliferation and apoptosis, energy metabolism, angiogenesis, invasion and metastasis, resistance to chemotherapy and radiotherapy. Given the specific expression and regulation of HIF-1 in HCC growth, HIF-1 may become a new target for drug therapy and gene therapy, which provides a new avenue for neoadjuvant therapy of HCC in the future.

Yttrium-90 Radioembolization in Patients with Hepatocellular Carcinoma Who have Previously Received Sorafenib

Purpose: Yttrium-90 radioembolization (RE) is a locoregional therapy option for hepatocellular carcinoma (HCC). Sorafenib is a multikinase inhibitor used in HCC that can potentially affect the efficacy of RE by altering tumor vascularity or suppressing post-irradiation angiogenesis. The safety and efficacy of sorafenib followed by RE has not been previously reported.

Materials and Methods: Patients with HCC who received RE after sorafenib were included in this retrospective review. Overall survival, toxicity, and maximal radiographic response and necrosis criteria were examined.

Results: Ten patients (15 RE administrations) fit the inclusion criteria. All were Barcelona Clinic Liver Cancer (BCLC) stage C. Median follow-up was 16.5 weeks. Median overall survival and radiographic progression-free survival were 30 and 28 weeks, respectively. Significant differences in overall survival were seen based on Child-Pugh class (p = 0.002) and radiographic response (p = 0.009). Three patients had partial response, six had stable disease, and one had progressive disease. Grade 1 or 2 acute fatigue, anorexia, and abdominal pain were common. Three patients had Grade 3 ascites in the setting of disease progression. Two patients had Grade 3 biochemical toxicity. One patient was sufficiently downstaged following RE and sorafenib to receive a partial hepatectomy.

Conclusion: Yttrium-90 RE in patients with HCC who have received sorafenib demonstrate acceptable toxicity and rates of radiographic response. However, the overall survival is lower than that reported in the literature on RE alone or sorafenib alone. This may be due in part to more patients in this study having advanced disease compared to these other study populations. Larger prospective studies are needed to determine whether the combination of RE and sorafenib is superior to either therapy alone.

HBx mutants differentially affect the activation of hypoxia-inducible factor-1α in hepatocellular carcinoma

BACKGROUND

Mutations in HBx gene are frequently found in HBV-associated hepatocellular carcinoma (HCC). Activation of hypoxia-inducible factor-1α (HIF-1α) contributes to HCC development and progression. Wild-type HBx has been demonstrated to activate HIF-1α, but the effect of HBx mutations on HIF-1α has not been elucidated.

METHODS

HBx mutations were identified by gene sequencing in 101 HCC tissues. Representative HBx mutants were cloned and transfected into HCC cells. Expression and activation of HIF-1α were analysed by western blot and luciferase assays, respectively. The relationship between HBx mutants and HIF-1α expression in HCC tissues was also evaluated.

RESULTS

The dual mutations K130M/V131I enhanced the functionality of HBx as they upregulated the expression and transcriptional activity of HIF-1α. The C-terminal truncations and deletion mutations, however, weakened the ability of HBx to upregulate HIF-1α. Meanwhile, the C-terminus was further found to be essential for the stability and transactivation of HBx. In the HCC tissues, there was a positive association between the HBx mutants and HIF-1α expression.

CONCLUSION

Different mutations of HBx exert differentiated effects on the functionality of HIF-1α, however, the overall activity of HBx mutants appears to increase the expression and transcriptional activity of HIF-1α.

The impact of hypoxia in hepatocellular carcinoma metastasis

Hypoxia is a common phenomenon in hepatocellular carcinoma (HCC). Hypoxia stabilizes transcription factor, hypoxia-inducible factor (HIF), to activate gene transcription. Expression of HIF is closely associated with metastasis and poor prognosis in HCC. HIF mediates expression of genes that are involved in every step of HCC metastasis including epithelial-mesenchymal transition, invasion of the extracellular matrix, intravasation, extravasation, and secondary growth of the metastases. Because HIF is the central regulator of HCC metastasis, HIF inhibitors are attractive tools when used alone or as combined treatment to curb HCC metastasis. This review will summarize the current findings on the impact of hypoxia/HIF in HCC, with a particular focus on cancer metastasis.

Advanced unresectable hepatocellular carcinoma: new biologics as fresh ammunition or clues to disease understanding?

PURPOSE OF REVIEW

Hepatocellular carcinoma (HCC) is a prevalent malignancy associated with a guarded prognosis. At present, sorafenib is the only approved systemic therapy for patients with advanced disease. The effect of sorafenib on overall survival is modest and limited in time by the occurrence of drug resistance.

RECENT FINDINGS

Together with the increasing knowledge of molecular pathways involved in HCC, targeted molecules have been developed and tested in first and second line following sorafenib. These include antiangiogenic drugs, as well as biologicals inhibiting cell proliferation and survival. Recent phase III trials investigated sunitinib, linifanib, brivanib and erlotinib, but none of them were found superior to sorafenib. New findings in mechanisms of drug resistance create opportunities in the treatment of sorafenib-refractory disease, with cMET inhibition as the most promising approach. This article reviews the pathways involved in HCC and their targets as well as potential strategies for drug development in the future.

SUMMARY

Advanced HCC has been the subject of intensive clinical research following the success of sorafenib. Despite many failures, some agents show promising results in phase II trials. Targeting new pathways, using multidrug regimens and tailoring treatment guided by predictive markers should allow new successes.

Transarterial embolization with sorafenib in animal livers: a pharmacokinetics study

PURPOSE

To assess the safety and feasibility of the targeted delivery of the antiangiogenic drug sorafenib to the liver using transarterial chemoembolization methodology as a novel approach to hepatocellular carcinoma (HCC) therapy.

MATERIALS AND METHODS

Seven healthy New Zealand white rabbits were used in the study. After placement of a catheter in the common hepatic artery, six rabbits were treated with chemoembolization of sorafenib in iodized oil (Lipiodol) (sorafenib dose 0.1 mg/kg), and one rabbit received Lipiodol only. Liquid chromatography tandem mass spectrometry was used to measure the concentration of sorafenib in the peripheral blood and liver tissue 24 hours and 72 hours after treatment. Histochemical staining of the liver sections and biochemical measurements were performed.

RESULTS

The administration of sorafenib in Lipiodol emulsions by transarterial chemoembolization resulted in sorafenib concentrations of 794 ng/g ± 240 and 64 ng/g ± 15 in the liver tissue 24 hours and 72 hours after treatment. The average liver-to-serum ratios 24 hours and 72 hours after treatment were approximately 14 and 22. The histochemical staining of the liver tissue sections and aspartate aminotransferase, alanine aminotransferase, γ-glutamyltransferase and total bilirubin concentrations indicated no significant liver damage.

CONCLUSIONS

Transarterial chemoembolization with sorafenib in Lipiodol is an effective methodology for the localized delivery of this drug to the liver and has possible practical implications in therapeutic interventions for the treatment of hepatocellular carcinoma.

A negative feedback of the HIF-1α pathway via interferon-stimulated gene 15 and ISGylation

PURPOSE

The IFN-stimulated gene 15 (ISG15)- and ubiquitin-conjugation pathways play roles in mediating hypoxic and inflammatory responses. To identify interaction(s) between these two tumor microenvironments, we investigated the effect of ISG15 on the activity of the master hypoxic transcription factor HIF-1α.

EXPERIMENTAL DESIGN

IFN and desferoxamine treatments were used to induce the expression of ISGs and HIF-1α, respectively. Interactions between HIF-1α and the ISG15 and ISGylation system were studied using knockdown of mRNA expression, immunoblotting, coimmunoprecipitation, and pull-down analyses. Effects of the ISG15 and ISGylation system on the HIF-1α-directed processes were examined using reporter, reverse transcription polymerase chain reaction (RT-PCR), and tumorigenic growth assays.

RESULTS

We found that the level of the free form of HIF-1α is differentially regulated by IFN treatment, and that the free ISG15 level is lower under hypoxia. Mechanism-directed studies have shown that HIF-1α not only interacts physically with ISG15, but is also ISGylated in multiple domains. ISG15 expression disrupts the functional dimerization of HIF-1α and -1β. Subsequently, expression of the ISG15 and/or ISGylation system attenuates HIF-1α-mediated gene expression and tumorigenic growth.

CONCLUSION

In summary, our results revealed cross-talk between inflammatory and hypoxic pathways through the ISGylation of HIF-1α. On the basis of these results, we propose a novel negative feedback loop for the HIF-1α-mediated pathway involving the regulation of HIF-1α via IFN-induced ISGylation.

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

Sorafenib, the unique drug as first-line treatment for advanced hepatocellular carcinoma (HCC), has opened a window of hope after searching for effective agents to combat HCC for decades. However, the overall outcomes are far from satisfactory. One of the explanations is the genetic heterogeneity of HCC, which has led to identifying predictive biomarkers for primary resistance to sorafenib, and then applying the concept of personalized medicine, or seeking therapeutic strategies such as combining sorafenib with other anticancer agents. Some of the combinations have demonstrated a better effectiveness than sorafenib alone, with good tolerance. The acquired resistance to sorafenib has also drawn attention. As a multikinase inhibitor, sorafenib targets several cellular signaling pathways but simultaneously or sequentially the addiction switches and compensatory pathways are activated. Several mechanisms are involved in the acquired resistance to sorafenib, such as crosstalks involving PI3K/Akt and JAK-STAT pathways, hypoxia-inducible pathways, epithelial-mesenchymal transition, etc. Based on the investigated mechanisms, some other molecular targeted drugs have been applied as second-line treatment for treat HCC after the failure of sorafenib therapy and more are under evaluation in clinical trials. However, the exact mechanisms accounting for sorafenib resistance remains unclear. Further investigation on the crosstalk and relationship of associated pathways will better our understanding of the mechanisms and help to find effective strategies for overcoming sorafenib resistance in HCC.

Relationship between vascular endothelial growth factors and liver diseases

Vascular endothelial growth factors play an important role in the processes of cell differentiation and maturation. As a kind of multi-functional factor, they are closely related to the occurrence and progression of liver diseases. They can not only promote postoperative liver regeneration but also repress the propagation of chronic hepatitis B and liver cirrhosis. In addition, they have a role in cancer diagnosis and treatment and graft rejection in liver transplantation. In this paper, we will give a brief introduction of vascular growth factors and their role in liver regeneration, cirrhosis, liver cancer and liver transplantation.

Menadione and ethacrynic acid inhibit the hypoxia-inducible factor (HIF) pathway by disrupting HIF-1α interaction with p300

Hypoxia is a general characteristic of most solid malignancies and intimately related to neoplastic diseases and cancer progression. Homeostatic response to hypoxia is primarily mediated by hypoxia inducible factor (HIF)-1α that elicits transcriptional activity through recruitment of the CREB binding protein (CBP)/p300 coactivator. Targeted blockade of HIF-1α binding to CBP/p300 would thus constitute a novel approach for cancer treatment by suppressing tumor angiogenesis and metastasis. Here, we identified inhibitors against the interaction between HIF-1α and p300 by a fluorescence polarization-based assay employing a fluorescently-labeled peptide containing the C-terminal activation domain of HIF-1α. Two small molecule inhibitors, menadione (MD) and ethacrynic acid (EA), were found to decrease expression of luciferase under the control of hypoxia-responsive elements in hypoxic cells as well as to efficiently block the interaction between the full-length HIF-1α and p300. While these compounds did not alter the expression level of HIF-1α, they down-regulated expression of a HIF-1α target vascular endothelial growth factor (VEGF) gene. Considering hypoxia-induced VEGF expression leading to highly aggressive tumor growth, MD and EA may provide new scaffolds for development of tumor therapeutic reagents as well as tools for a better understanding of HIF-1α-mediated hypoxic regulation.

Sorafenib inhibits lymphoma xenografts by targeting MAPK/ERK and AKT pathways in tumor and vascular cells

The anti-lymphoma activity and mechanism(s) of action of the multikinase inhibitor sorafenib were investigated using a panel of lymphoma cell lines, including SU-DHL-4V, Granta-519, HD-MyZ, and KMS-11 cell lines. In vitro, sorafenib significantly decreased cell proliferation and phosphorylation levels of MAPK and PI3K/Akt pathways while increased apoptotic cell death. In vivo, sorafenib treatment resulted in a cytostatic rather than cytotoxic effect on tumor cell growth associated with a limited inhibition of tumor volumes. However, sorafenib induced an average 50% reduction of tumor vessel density and a 2-fold increase of necrotic areas. Upon sorafenib treatment, endothelial and tumor cells from SU-DHL-4V, Granta-519, and KMS-11 nodules showed a potent inhibition of either phospho-ERK or phospho-AKT, whereas a concomitant inhibition of phospho-ERK and phospho-AKT was only observed in HD-MyZ nodules. In conclusion, sorafenib affects the growth of lymphoid cell lines by triggering antiangiogenic mechanism(s) and directly targeting tumor cells.

Recent progress in understanding the effect of interventional therapy for hepatic carcinoma on immune function

Liver cancer is a common highly malignant tumor in China, with a high rate of recurrence and metastasis. The body's immune function is closely related with the occurrence and development of liver cancer, and low immunological function is an important reason why hepatic carcinoma is hard to cure and tend to recur and metastasize. At present, surgery-based comprehensive therapy plays a dominant role in the treatment of hepatic carcinoma; however, the majority of patients had lost their opportunities for surgical treatment when a definitive diagnosis was established. Interventional therapy is regarded as the first choice of nonsurgical treatment for hepatic carcinoma. Interventional therapy can not only result in coagulative tumor necrosis but also promote apoptosis of tumor cells. The body's immune function can be enhanced to improve the anti-tumor ability by interventional therapy, especially the cellular immune function. As a result, the metastasis and recurrence of hepatic carcinoma may be inhibited. The purpose of this article is to review the progress in understanding the effect of interventional therapy for hepatic carcinoma on immune function.