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.     

非编码RNA在索拉非尼治疗肝细胞癌耐药中的作用机制

索拉非尼作为晚期肝细胞癌的一线治疗药物,能够有效改善肝癌患者预后。但索拉非尼耐药已经成为影响肝细胞癌治疗效果的主要障碍。近年来研究发现,非编码RNA在肝细胞癌索拉非尼耐药中起着关键作用。总结了非编码RNA通过诱导肝癌细胞自噬、促进肝癌干细胞增殖、促进肝癌细胞上皮-间质转化过程、抑制肝癌细胞凋亡以及调节肝癌组织微环境来调节肝癌细胞对索拉非尼的敏感性。指出了非编码RNA调控肝细胞癌索拉非尼耐药的分子机制在克服耐药方面的潜在临床意义。     

Sorafenib enhances proteasome inhibitor-induced cell death via inactivation of Akt and stress-activated protein kinases

Background

Advanced hepatocellular carcinoma (HCC) responds poorly to conventional systemic therapies. Therefore, new effective therapy strategies are urgently needed. Molecular targeted therapies have entered the field of anti-neoplastic treatment and are being used on their own and in combination with other drugs. Sorafenib inhibits proliferation and angiogenesis of HCC by suppressing the Raf serine/threonine kinases and the receptor tyrosine kinases. The proteasome inhibitor bortezomib has shown activity in a variety of solid tumors, including HCC. However, the precise anti-proliferative mechanisms of these agents remain unclear.

Methods

We treated human hepatoma cell lines (Huh7 and Hep3B) and immortalized human hepatocyte (OUMS29) with sorafenib and/or proteasome inhibitors, including epoxomicin and acetyl-leucyl-leucyl-norleucinal. Cytotoxic effects were examined by morphometric analyses of apoptosis and necrosis. Apoptosis was also evaluated by Western blotting of keratin18, PARP and caspase3. The activity of Akt and stress-activated protein kinases was examined by Western blotting.

Results

Both sorafenib and proteasome inhibitors induced apoptosis in Huh7 and OUMS29. However, sorafenib attenuated proteasome inhibitor-induced apoptosis. Sorafenib induced necrosis, especially in combination with proteasome inhibitors. Sorafenib induced down-regulation of Akt synergistically in combination with proteasome inhibitors in Huh7. Sorafenib inhibited both the JNK and p38 pathways in a time- and dose-dependent manner. In addition, sorafenib also inhibited proteasome inhibitor-mediated JNK and p38 activation in both Huh7 and OUMS29.

Conclusions

Sorafenib enhances the anti-proliferative effect of proteasome inhibitors in part by inactivating the Akt signaling pathway and modulating stress-activated protein kinases. The combination of these agents could be an ideal molecular targeted therapy for HCC.     

Management of advanced hepatocellular carcinoma in the era of targeted therapy

Systemic chemotherapy has had a disappointing track record in the management of advanced hepatocellular carcinoma (HCC). Single‐agent doxorubicin produces a response rate of 10–15%, but without any survival benefit, and combination chemotherapy has also yielded unimpressive results. With recent advances in the knowledge of hepato‐carcinogenesis, there has been encouraging development in the systemic therapy of advanced HCC patients, and particularly in the targeted therapy of advanced HCC. Among the newly identified targets, exciting results have been shown in targeting the anti‐angiogenic pathway and the Raf/mitogen‐activated protein kinase pathways. Bevacizumab, both as a single agent and in combination with other agents, has shown initial encouraging activity in treating advanced HCC. More recently, single‐agent sorafenib, a putative multitargeted kinase inhibitor, has shown to prolong the overall survival of patients with advanced HCC in the pivotal phase III Sorafenib HCC Assessment Randomized Protocol (SHARP) and Oriental study. Currently, sorafenib is the only approved targeted therapy for patients with advanced HCC. In addition, however, promising early results have been reported for other molecular‐targeted drugs including erlotinib and sunitinib. Future progress seems likely to depend on using controlled clinical trials to optimize synergistic combination treatments.     

Y-box binding protein 1 augments sorafenib resistance via the PI3K/Akt signaling pathway in hepatocellular carcinoma

BACKGROUNDSorafenib is the first-line treatment for patients with advanced hepatocellular carcinoma (HCC). Y-box binding protein 1 (YB-1) is closely correlated with tumors and drug resistance. However, the relationship between YB-1 and sorafenib resistance and the underlying mechanism in HCC remain unknown.AIMTo explore the role and related mechanisms of YB-1 in mediating sorafenib resistance in HCC.METHODSThe protein expression levels of YB-1 were assessed in human HCC tissues and adjacent nontumor tissues. Next, we constructed YB-1 overexpression and knockdown hepatocarcinoma cell lines with lentiviruses and stimulated these cell lines with different concentrations of sorafenib. Then, we detected the proliferation and apoptosis in these cells by terminal deoxynucleotidyl transferase dUTP nick end labeling, flow cytometry and Western blotting assays. We also constructed a xenograft tumor model to explore the effect of YB-1 on the efficacy of sorafenib in vivo. Moreover, we studied and verified the specific molecular mechanism of YB-1 mediating sorafenib resistance in hepatoma cells by digital gene expression sequencing (DGE-seq).RESULTSYB-1 protein levels were found to be higher in HCC tissues than in corresponding nontumor tissues. YB-1 suppressed the effect of sorafenib on cell proliferation and apoptosis. Consistently, the efficacy of sorafenib in vivo was enhanced after YB-1 was knocked down. Furthermore, KEGG pathway enrichment analysis of DGE-seq demonstrated that the phosphoinositide-3-kinase (PI3K)/protein kinase B (Akt) signaling pathway was essential for the sorafenib resistance induced by YB-1. Subsequently, YB-1 interacted with two key proteins of the PI3K/Akt signaling pathway (Akt1 and PIK3R1) as shown by searching the BioGRID and HitPredict websites. Finally, YB-1 suppressed the inactivation of the PI3K/Akt signaling pathway induced by sorafenib, and the blockade of the PI3K/Akt signaling pathway by LY294002 mitigated YB-1-induced sorafenib resistance.CONCLUSIONOverall, we concluded that YB-1 augments sorafenib resistance through the PI3K/Akt signaling pathway in HCC and suggest that YB-1 is a key drug resistance-related gene, which is of great significance for the application of sorafenib in advanced-stage HCC.     

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.     

索拉菲尼在肝癌治疗中的不良反应

索拉菲尼可以显著改善晚期肝癌患者的预后,它主要通过拮抗血管内皮生长因子受体和血小板衍生生长因子受体抗血管源性靶点及通过抑制Raf/MEK/ERK信号传导通路直接抑制肿瘤生长而发挥抗肿瘤作用。然而,频发的索拉菲尼相关的不良反应将影响患者的生活质量。文中简述了小分子靶向药物索拉菲尼治疗肝癌的药理机制,归纳总结了索拉菲尼相关常见不良反应的发生率、特点、预防和治疗措施,并指出索拉菲尼相关的不良反应和抗肿瘤疗效相关,认为临床医生应该充分权衡索拉菲尼在治疗肝癌患者中不良反应的利与弊。     

Torin2 overcomes sorafenib resistance via suppressing mTORC2-AKT-BAD pathway in hepatocellular carcinoma cells

BackgroundSorafenib is an oral multi-kinase inhibitor that was approved by the US Food and Drug Administration for the treatment of patients with advanced hepatocellular carcinoma (HCC). However, resistance to sorafenib is an urgent problem to be resolved to improve the therapeutic efficacy of sorafenib. As the activation of AKT/mTOR played a pivotal role in sorafenib resistance, we evaluated the effect of a dual mTOR complex 1/2 inhibitor Torin2 on overcoming the sorafenib resistance in HCC cells.MethodsThe sorafenib-resistant Huh7 and Hep3B cell lines were established from their parental cell lines. The synergistic effect of sorafenib and Torin2 on these cells was measured by cell viability assay and quantified using the Chou-Talalay method. Apoptosis induced by the combination of sorafenib and Torin2 and the alteration in the specific signaling pathways of interest were detected by Western blotting.ResultsSorafenib treatment inversely inhibited AKT in parental but activated AKT in sorafenib-resistant Huh7 and Hep3B HCC cells, which underscores the significance of AKT activation. Torin2 and sorafenib synergistically suppressed the viability of sorafenib-resistant cells via apoptosis induction. Torin2 successfully suppressed the sorafenib-activated mTORC2-AKT axis, leading to the dephosphorylation of Ser136 in BAD protein, and increased the expression of total BAD, which contributed to the apoptosis in sorafenib-resistant HCC cells.ConclusionsIn this study, Torin2 and sorafenib showed synergistic cytostatic capacity in sorafenib-resistant HCC cells, via the suppression of mTORC2-AKT-BAD pathway. Our results suggest a novel strategy of drug combination for overcoming sorafenib resistance in HCC.     

Increased glutathione and mitogen‐activated protein kinase phosphorylation are involved in the induction of doxorubicin resistance in hepatocellular carcinoma cells

Aim: The human hepatocellular carcinoma (HCC) cell line HepG2 can easily acquire resistance to doxorubicin. However, the mechanism of action is unclear. Methods: In the present study, we used confocal microscopy, flow cytometry and other methods to reveal the mechanisms by which HepG2 cells acquire doxorubicin resistance. Results: Our results showed that R‐HepG2 cells, a doxorubicin‐resistant sub‐line of HepG2, exhibited decreased intracellular accumulation of doxorubicin and increased expression of P‐glycoprotein (P‐gp) and multidrug resistance‐associated protein 1 when compared with HepG2 cells. R‐HepG2 cells also harbored higher levels of glutathione and increased expression of glutathione peroxidase. Furthermore, we demonstrated that the phosphorylation of mitogen‐activated protein kinases (p38 and c‐jun‐N‐terminal kinases), IkBα and CREB were increased in R‐HepG2 cells. Specific p38 inhibitor SB203580 decreased P‐gp expression. The multi‐kinase inhibitor sorafenib tosylate also significantly suppressed the phosphorylation of these proteins and inhibited the expression of P‐gp. Conclusion: These findings reveal that the drug resistance could be acquired through mitogen‐activated protein kinase‐dependent upregulation of P‐gp. This mechanism protects R‐HepG2 cells from the anticancer action of doxorubicin.     

Sorafenib in a hepatocellular carcinoma patient with end‐stage renal failure: A pharmacokinetic study

The efficacy of sorafenib against hepatocellular carcinoma (HCC) has been extensively reported. However, there is little information available about the use of sorafenib for HCC patients with end‐stage renal failure. We herein report the safe introduction of sorafenib therapy for a HCC patient on hemodialysis. A 63‐year‐old man had received multidisciplinary treatments, including transarterial chemoembolization (TACE) and radiofrequency ablation, for HCC since 1996, and had been undergoing hemodialysis since 2005. He also underwent TACE for multiple liver recurrence of HCC in 2011. Sorafenib therapy (200 mg/day) started 8 days after the TACE. The pharmacokinetic parameters of sorafenib and its active metabolite, M‐2, were within the reference levels observed in patients with normal renal function 8 and 9 days after the initiation of sorafenib. The dose of sorafenib was reduced to 200 mg every other day on day 154 due to hypertension and general fatigue. Because of the progression of disease after 5 months, sorafenib was withdrawn on day 180. He was admitted to the emergency department because of a high fever during hemodialysis on day 201, and died of septic shock induced by Staphylococcus lugdunensis on day 203. Sorafenib was well tolerated at an initial dose of 200 mg/day for a HCC patient undergoing hemodialysis, thus indicating that renal failure is not necessarily a contraindication for sorafenib therapy.     

Evolution of systemic therapy of advanced hepatocellular carcinoma

Hepatocellular carcinoma （HCC） commonly occurs in hepatitis B endemic areas, especially in Asian countries. HCC is highly refractory to cytotoxic chemotherapy. This resistance is partly related to its tumor biology, pharmacokinetic properties, and both intrinsic and acquired drug resistance. There is no convincing evidence thus far that systemic chemotherapy improves overall survival in advanced HCC patients. Other systemic approaches, such as hormonal therapy and immunotherapy, have also disappointing results. Recently, encouraging results have been shown in using sorafenib in the treatment of advanced HCC patients. In this review, we concisely summarize the evolution of developments in the systemic therapy of advanced HCC.     

Medical treatments: in association or alone, their roles and their future perspectives

Management of hepatocellular carcinoma (HCC) is a complex issue, as it needs to take into account the liver disease, the cancer stage and the performance status of the patient. The treatment decision has to be based on robust scientific evidence and for this it is instrumental to have a proper staging system linked to the treatment indication. The BCLC proposal serves these two purposes and has been validated worldwide and endorsed by several scientific associations. The sole systemic therapy that has shown efficacy in improving the survival of HCC patients is sorafenib, an oral kinase inhibitor that blocks the Raf/MEK/ERK pathway and the receptor for VEGFR 2 and PDGFR-beta. Sorafenib has been recognized as the standard of care for patients who cannot benefit from treatments of higher priority and established efficacy, such as surgical resection, transplantation, ablation and transarterial chemoembolization. Sorafenib has changed the management of HCC, opening the path to combination therapies for patients at advanced stages and to evaluation as an adjuvant for those in earlier evolutionary stages.     

Current status and future prospects of chemotherapy for advanced hepatocellular carcinoma

Sorafenib is the only drug that demonstrates a survival benefit for advanced hepatocellular carcinoma (HCC). However, the therapeutic effect of sorafenib is limited, so development of a more effective treatment method and second-line treatments is needed. Since the advent of sorafenib, clinical studies have been conducted with a variety of drugs and treatment methods, mainly with molecular targeted therapy, but almost all trials have ended in failure. The reasons for the difficulty in the development of a novel drug or treatment method include the diversity of mechanisms in the carcinogenesis and development of HCC, as well as the presence of background liver diseases such as chronic hepatitis and cirrhosis. Trials with immune-checkpoint inhibitors, which have an entirely different anti-tumor mechanism from that of molecular targeted drugs or cytotoxic drugs, have recently begun. Based on the results to date, clinical trials are now being conducted with enriched target subjects. In the future, providing more individualized treatment approaches for patients with advanced HCC will be essential.     

Melatonin‐induced increase in sensitivity of human hepatocellular carcinoma cells to sorafenib is associated with reactive oxygen species production and mitophagy

Effects of sorafenib in hepatocellular carcinoma (HCC) are frequently transient due to tumor‐acquired resistance, a phenotype that could be targeted by other molecules to reduce this adaptive response. Because melatonin is known to exert antitumor effects in HCC cells, this study investigated whether and how melatonin reduces resistance to sorafenib. Susceptibility to sorafenib (10 nmol/L to 50 μmol/L) in the presence of melatonin (1 and 2 mmol/L) was assessed in HCC cell lines HepG2, HuH7, and Hep3B. Cell viability was reduced by sorafenib from 1 μmol/L in HepG2 or HuH7 cells, and 2.5 μmol/L in Hep3B cells. Co‐administration of melatonin and sorafenib exhibited a synergistic cytotoxic effect on HepG2 and HuH7 cells, while Hep3B cells displayed susceptibility to doses of sorafenib that had no effect when administrated alone. Co‐administration of 2.5 μmol/L sorafenib and 1 mmol/L melatonin induced apoptosis in Hep3B cells, increasing PARP hydrolysis and BAX expression. We also observed an early colocalization of mitochondria with lysosomes, correlating with the expression of mitophagy markers PINK1 and Parkin and a reduction of mitofusin‐2 and mtDNA compared with sorafenib administration alone. Moreover, increased reactive oxygen species production and mitochondrial membrane depolarization were elicited by drug combination, suggesting their contribution to mitophagy induction. Interestingly, Parkin silencing by siRNA to impair mitophagy significantly reduced cell killing, PARP cleavage, and BAX expression. These results demonstrate that the pro‐oxidant capacity of melatonin and its impact on mitochondria stability and turnover via mitophagy increase sensitivity to the cytotoxic effect of sorafenib.     

CircRNA-001241 mediates sorafenib resistance of hepatocellular carcinoma cells by sponging miR-21-5p and regulating TIMP3 expression

Hepatocellular carcinoma (HCC) is one of the major malignancies worldwide and its incidence is on the rise, closely related to advanced liver disease. Sorafenib chemotherapy is one of the main treatment options for patients with advanced HCC. Despite several reports on HCC multidrug resistance, the underlying regulatory mechanisms are still unclear. In this study, we found circ-001241 was significantly upregulated in HCC tissues and cells. Knockdown of circ-001241 markedly inhibited HCC cell proliferation and decreased sorafenib-resistance. More importantly, circRNA acts as a ceRNA to suppress the expression and activity of miR-21-5p, leading to the increase in TIMP3 expression. In addition, circRNA-001241 facilitated HCC sorafenib-resistance by regulating the miR-21-5p/TIMP3 axis. Taken together, our study elucidated the oncogenic role of circ-001241 in mediating sorafenib resistance in HCC, providing insights and opportunities to overcome sorafenib resistance in patients with advanced hepatocellular carcinoma.     

Sorafenib decreases proliferation and induces apoptosis of prostate cancer cells by inhibition of the androgen receptor and Akt signaling pathways

Antihormonal and chemotherapy are standard treatments for nonorgan-confined prostate cancer. The effectivity of these therapies is limited and the development of alternative approaches is necessary. In the present study, we report on the use of the multikinase inhibitor sorafenib in a panel of prostate cancer cell lines and their derivatives which mimic endocrine and chemotherapy resistance. (3)H-thymidine incorporation assays revealed that sorafenib causes a dose-dependent inhibition of proliferation of all cell lines associated with downregulation of cyclin-dependent kinase 2 and cyclin D1 expression. Apoptosis was induced at 2 μM of sorafenib in androgen-sensitive cells, whereas a higher dose of the drug was needed in castration-resistant cell lines. Sorafenib stimulated apoptosis in prostate cancer cell lines through downregulation of myeloid cell leukemia-1 (MCL-1) expression and Akt phosphorylation. Although concentrations of sorafenib required for the antitumor effect in therapy-resistant sublines were higher than those needed in parental cells, the drug showed efficacy in cells which became resistant to bicalutamide and docetaxel respectively. Most interestingly, we show that sorafenib has an inhibitory effect on androgen receptor (AR) and prostate-specific antigen expression. In cells in which AR expression was downregulated by short interfering RNA, the treatment with sorafenib increased apoptosis in an additive manner. In summary, the results of the present study indicate that there is a potential to use sorafenib in prostate cancers as an adjuvant therapy option to current androgen ablation treatments, but also in progressed prostate cancers that become unresponsive to standard therapies.     

Tumor lysis syndrome after sorafenib for hepatocellular carcinoma: a case report

We encountered a patient who developed marked renal impairment and hyperuricemia in a short period after sorafenib administration, which suggested tumor lysis syndrome (TLS). A 79-year-old woman with hepatitis C-related liver cirrhosis was found to have intermediate hepatocellular carcinoma (HCC) according to Barcelona Clinic Cancer staging classification. Pre-treatment laboratory tests showed mild renal impairment. On the 10th day of sorafenib intake, the creatinine and uric acid levels rose to 2.99 and 16.1 mg/dl, respectively, and arterial blood gas analysis showed respiratory compensated metabolic acidosis, which suggested grade I clinical TLS according to the diagnostic criteria of TLS as defined by Cairo-Bishop. TLS is a group of metabolic abnormalities that arise from the rapid breakdown of many tumor cells upon the initiation of malignant tumor chemotherapy, resulting in the release of intracellular metabolites that exceed the ability of the kidney to excrete them. TLS occurs more rarely in solid tumors, including HCC, than in hematologic malignancies. Sorafenib is administered to patients with renal impairment at recommended doses. However, the drug may cause TLS or severe renal impairment in advanced HCC patients with preexisting mild renal impairment, necessitating reduced-dose therapy and careful follow-up after the start of therapy to facilitate early diagnosis and treatment. This is a very rare complication developed in a short period treated with sorafenib as a single-agent for an advanced HCC.     

MicroRNAs contribute to ATP-binding cassette transporter-and autophagy-mediated chemoresistance in hepatocellular carcinoma

Hepatocellular carcinoma(HCC) has an elevated mortality rate, largely because of high recurrence and metastasis. Additionally, the main obstacle during treatment of HCC is that patients usually develop resistance to chemotherapy.Cancer drug resistance involves many different mechanisms, including alterations in drug metabolism and processing, impairment of the apoptotic machine, activation of cell survival signaling, decreased drug sensitivity and autophagy, among others. Nowadays, miRNAs are emerging as master regulators of normal physiology-and tumor-related gene expression. In HCC,aberrant expression of many miRNAs leads to chemoresistance. Herein, we particularly analyzed miRNA impact on HCC resistance to drug therapy. Certain miRNAs target ABC(ATP-binding cassette) transporter genes. As most of these miRNAs are downregulated in HCC, transporter levels increase and intracellular drug accumulation decrease, turning cells less sensitive to death. Others miRNAs target autophagy-related gene expression, inhibiting autophagy and acting as tumor suppressors. Nevertheless, due to its downregulation in HCC, these miRNAs do not inhibit autophagy or tumor growth and, resistance is favored.Concluding, modulation of ABC transporter and/or autophagy-related gene expression or function by miRNAs could be determinant for HCC cell survival under chemotherapeutic drug treatment. Undoubtedly, more insights on the biological processes, signaling pathways and/or molecular mechanisms regulated by miRNAs are needed. Anyway, miRNA-based therapy together with conventional chemotherapeutic drugs has a great future in cancer therapy.     

Melatonin promotes sorafenib‐induced apoptosis through synergistic activation of JNK/c‐jun pathway in human hepatocellular carcinoma

Melatonin has been shown to exert anticancer activity on hepatocellular carcinoma (HCC) through its antiproliferative and pro‐apoptotic effect in both experimental and clinical studies, and sorafenib is the only approved drug for the systemic treatment of HCC. Thus, this study was designed to investigate the combined effect of melatonin and sorafenib on proliferation, apoptosis, and its possible mechanism in human HCC. Here, we found that both melatonin and sorafenib resulted in a dose‐dependent growth inhibition of HuH‐7 cells after 48 hours treatment, and the combination of them enhanced the growth inhibition in a synergistic manner. Colony formation assay indicated that co‐treatment of HuH‐7 cells with melatonin and sorafenib significantly decreased the clonogenicity compared to the treatment with single agent. Furthermore, FACS and TUNEL assay confirmed that melatonin synergistically augmented the sorafenib‐induced apoptosis after 48 hours incubation, which was in accordance with the activation of caspase‐3 and the JNK/c‐jun pathway. Inhibition of JNK/c‐jun pathway with its inhibitor SP600125 reversed the phosphorylation of c‐jun and the activation of caspase‐3 induced by co‐treatment of HuH‐7 cells with melatonin and sorafenib in a dose‐dependent manner. Furthermore, SP600125 exhibited protective effect against apoptosis induced by the combination of melatonin and sorafenib. This study demonstrates that melatonin in combination with sorafenib synergistically inhibits proliferation and induces apoptosis in human HCC cells; therefore, supplementation of sorafenib with melatonin may serve as a potential therapeutic choice for advanced HCC.