We recently noted that low doses of sorafenib and vorinostat interact in a synergistic fashion to kill carcinoma cells by activating CD95, and this drug combination is entering phase I trials. The present studies mechanistically extended our initial observations. Low doses of sorafenib and vorinostat, but not the individual agents, caused an acidic sphingomyelinase and fumonisin B1-dependent increase in CD95 surface levels and CD95 association with caspase 8. Knock down of CD95 or FADD expression reduced sorafenib/vorinostat lethality. Signaling by CD95 caused PERK activation that was responsible for both promoting caspase 8 association with CD95 and for increased eIF2α phosphorylation; suppression of eIF2α function abolished drug combination lethality. Cell killing was paralleled by PERK- and eIF2α-dependent lowering of c-FLIP-s protein levels and over-expression of c-FLIP-s maintained cell viability. In a CD95-, FADD- and PERK-dependent fashion, sorafenib and vorinostat increased expression of ATG5 that was responsible for enhanced autophagy. Expression of PDGFRβ and FLT3 were essential for high dose single agent sorafenib treatment to promote autophagy. Suppression of PERK function reduced sorafenib and vorinostat lethality whereas suppression of ATG5 levels elevated sorafenib and vorinostat lethality. Over-expression of c-FLIP-s blocked apoptosis and enhanced drug-induced autophagy. Thus sorafenib and vorinostat promote ceramide-dependent CD95 activation followed by induction of multiple downstream survival regulatory signals: ceramide-CD95-PERK-FADD-pro-caspase 8 (death); ceramide-CD95-PERK-eIF2α -↓c-FLIP-s (death); ceramide-CD95-PERK-ATG5-autophagy (survival).
Vorinostat; Sorafenib; CD95; c-FLIP-s; PDGFRβ; FLT3; autophagy; ceramide; cell death; ASMase
The targeted therapeutics sorafenib and vorinostat interact in a synergistic fashion to kill carcinoma cells by activating CD95, and this drug combination is entering phase I evaluation. In this study we determined how CD95 is activated by treatment with this drug combination. Low doses of sorafenib and vorinostat but not the individual drugs rapidly increased ROS, Ca2+ and ceramide levels in GI tumor cells. The production of ROS was reduced in Rho zero cells. Quenching ROS blocked drug-induced CD95 surface localization and apoptosis. ROS generation, CD95 activation and cell killing was also blocked by quenching of induced Ca2+ levels or by inhibition of PP2A. Inhibition of acidic sphingomyelinase or de novo ceramide generation blocked the induction of ROS however combined inhibition of both acidic sphingomyelinase and de novo ceramide generation was required to block the induction of Ca2+. Quenching of ROS did not impact on drug-induced ceramide/dihydro-ceramide levels whereas quenching of Ca2+ reduced the ceramide increase. Sorafenib and vorinostat treatment radiosensitized liver and pancreatic cancer cells, an effect that was suppressed by quenching ROS or knock down of LASS6. Further, sorafenib and vorinostat treatment suppressed the growth of pancreatic tumors in vivo. Our findings demonstrate that induction of cytosolic Ca2+ by sorafenib and vorinostat is a primary event that elevates dihydroceramide levels, each essential steps in ROS generation that promotes CD95 activation.
Purpose and Design
Mechanism(s) by which the multi-kinase inhibitor sorafenib and the histone deacetylase inhibitor vorinostat interact to kill hepatic, renal and pancreatic adenocarcinoma cells have been defined.
Low doses of sorafenib and vorinostat interacted in vitro in a synergistic fashion to kill hepatic, renal and pancreatic adenocarcinoma cells in multiple short term viability (24–96h) and in long term colony formation assays. Cell killing was suppressed by inhibition of cathepsin proteases and caspase 8, and to a lesser extent by inhibition of caspase 9. Twenty four hours after exposure, the activities of ERK1/2, AKT and NFκB were only modestly modulated by sorafenib and vorinostat treatment. However, 24h after exposure, sorafenib and vorinostat- treated cells exhibited markedly diminished expression of c-FLIP-s, full length BID, BCL-2, BCLXL, MCL-1, XIAP, increased expression of BIM, and increased activation of BAX, BAK and BAD. Expression of eIF2α S51A blocked sorafenib and vorinostat –induced suppression of c-FLIP-s levels and over-expression of c-FLIP-s abolished lethality. Sorafenib and vorinostat treatment increased surface levels of CD95 and CD95 association with caspase 8. Knock down of CD95 or FADD expression significantly reduced sorafenib / vorinostat -mediated lethality.
These data demonstrate that combined exposure of epithelial tumor cell types to sorafenib and vorinostat diminishes expression of multiple anti-apoptotic proteins, promotes activation of the CD95 extrinsic apoptotic and the lysosomal protease pathways, and that suppression of c-FLIP-s expression represents a critical event in transduction of the pro-apoptotic signals from CD95 to promote mitochondrial dysfunction and death.
Vorinostat; Sorafenib; CD95; c-FLIP-s; caspase 8; cathepsin; cell death
Sorafenib, a multi-tyrosine kinase inhibitor, kills more effectively the non-metastatic prostate cancer cell line 22Rv1 than the highly metastatic prostate cancer cell line PC3. In 22Rv1 cells, constitutively active STAT3 and ERK are targeted by sorafenib, contrasting with PC3 cells, in which these kinases are not active. Notably, overexpression of a constitutively active MEK construct in 22Rv1 cells stimulates the sustained phosphorylation of Bad and protects from sorafenib-induced cell death. In PC3 cells, Src and AKT are constitutively activated and targeted by sorafenib, leading to an increase in Bim protein levels. Overexpression of constitutively active AKT or knockdown of Bim protects PC3 cells from sorafenib-induced killing. In both PC3 and 22Rv1 cells, Mcl-1 depletion is required for the induction of cell death by sorafenib as transient overexpression of Mcl-1 is protective. Interestingly, co-culturing of primary cancer-associated fibroblasts (CAFs) with 22Rv1 or PC3 cells protected the cancer cells from sorafenib-induced cell death, and this protection was largely overcome by co-administration of the Bcl-2 antagonist, ABT737. In summary, the differential tyrosine kinase profile of prostate cancer cells defines the cytotoxic efficacy of sorafenib and this profile is modulated by CAFs to promote resistance. The combination of sorafenib with Bcl-2 antagonists, such as ABT737, may constitute a promising therapeutic strategy against prostate cancer.
prostate cancer; tyrosine kinase inhibitor; sorafenib; apoptosis; autophagy; ABT737
Pemetrexed (ALIMTA) is a folate anti-metabolite that has been approved for the treatment of non-small cell lung cancer, and has been shown to stimulate autophagy. In the present study, we sought to further understand the role of autophagy in the response to pemetrexed and to test if combination therapy could enhance the level of toxicity through altered autophagy in tumor cells. The multikinase inhibitor sorafenib (NEXAVAR), used in the treatment of renal and hepatocellular carcinoma, suppresses tumor angiogenesis and promotes autophagy in tumor cells. We found that sorafenib interacted in a greater than additive fashion with pemetrexed to increase autophagy and to kill a diverse array of tumor cell types. Tumor cell types that displayed high levels of cell killing after combination treatment showed elevated levels of AKT, p70 S6K and/or phosphorylated mTOR, in addition to class III RTKs such as PDGFRβ and VEGFR1, known in vivo targets of sorafenib. In xenograft and in syngeneic animal models of mammary carcinoma and glioblastoma, the combination of sorafenib and pemetrexed suppressed tumor growth without deleterious effects on normal tissues or animal body mass. Taken together, the data suggest that premexetred and sorafenib act synergistically to enhance tumor killing via the promotion of a toxic form of autophagy that leads to activation of the intrinsic apoptosis pathway, and predict that combination treatment represents a future therapeutic option in the treatment of solid tumors.
pemetrexed; sorafenib; autophagy; apoptosis; PDGFR; ZMP; AMP; thymidylate synthase
Pemetrexed (ALIMTA) is a folate anti-metabolite that has been approved for the treatment of non-small cell lung cancer, and has been shown to stimulate autophagy. In the present study, we sought to further understand the role of autophagy in the response to pemetrexed and to test if combination therapy could enhance the level of toxicity through altered autophagy in tumor cells. The multi-kinase inhibitor sorafenib (NEXAVAR), used in the treatment of renal and hepatocellular carcinoma, suppresses tumor angiogenesis and promotes autophagy in tumor cells. We found that sorafenib interacted in a greater than additive fashion with pemetrexed to increase autophagy and to kill a diverse array of tumor cell types. Tumor cell types that displayed high levels of cell killing after combination treatment showed elevated levels of AKT, p70 S6K and/or phosphorylated mTOR, in addition to Class III RTKs such as PDGFRβ and VEGFR1, known in vivo targets of sorafenib. In xenograft and in syngeneic animal models of mammary carcinoma and glioblastoma, the combination of sorafenib and pemetrexed suppressed tumor growth without deleterious effects on normal tissues or animal body mass. Taken together, the data suggest that premexetred and sorafenib act synergistically to enhance tumor killing via the promotion of a toxic form of autophagy that leads to activation of the intrinsic apoptosis pathway, and predict that combination treatment represents a future therapeutic option in the treatment of solid tumors.
The Janus kinase/signal transducer and activator of transcription (JAK/STAT) pathway is one of the key signaling cascades in cholangiocarcinoma (CCA) cells, mediating their resistance to apoptosis. Our aim was to ascertain if sorafenib, a multikinase inhibitor, may also inhibit JAK/STAT signaling and, therefore, be efficacious for CCA. Sorafenib treatment of three human CCA cell lines resulted in Tyr705 phospho-STAT3 dephosphorylation. Similar results were obtained with the Raf-kinase inhibitor ZM336372, suggesting sorafenib promotes Tyr705 phospho-STAT3 dephosphorylation by inhibiting Raf-kinase activity. Sorafenib treatment enhanced an activating phosphorylation of the phosphatase SHP2. Consistent with this observation, small interfering RNA–mediated knockdown of phosphatase shatterproof 2 (SHP2) inhibited sorafenib-induced Tyr705 phospho-STAT3 dephosphorylation. Sorafenib treatment also decreased the expression of Mcl-1 messenger RNA and protein, a STAT3 transcriptional target, as well as sensitizing CCA cells to tumor necrosis factor–related apoptosis-inducing ligand (TRAIL)-mediated apoptosis. In an orthotopic, syngeneic CCA model in rats, sorafenib displayed significant tumor suppression resulting in a survival benefit for treated animals. In this in vivo model, sorafenib also decreased tumor Tyr705 STAT3 phosphorylation and increased tumor cell apoptosis.
Sorafenib accelerates STAT3 dephosphorylation by stimulating phosphatase SHP2 activity, sensitizes CCA cells to TRAIL-mediated apoptosis, and is therapeutic in a syngeneic rat, orthotopic CCA model that mimics human disease.
The present studies were designed to determine whether the multi-kinase inhibitor sorafenib (Nexavar) interacted with histone deacetylase inhibitors to kill glioblastoma and medulloblastoma cells. In a dose-dependent fashion sorafenib lethality was enhanced in multiple genetically disparate primary human glioblastoma isolates by the HDAC inhibitor sodium valproate (Depakote). Drug exposure reduced phosphorylation of p70 S6K and of mTOR. Similar data to that with valproate were also obtained using the HDAC inhibitor vorinostat (Zolinza). Sorafenib and valproate also interacted to kill medulloblastoma and PNET cell lines. Treatment with sorafenib and HDAC inhibitors radio-sensitized both GBM and medulloblastoma cell lines. Knock down of death receptor (CD95) expression protected GBM cells from the drug combination, as did overexpression of c-FLIP-s, BCL-XL and dominant negative caspase 9. Knock down of PDGFRα recapitulated the effect of sorafenib in combination with HDAC inhibitors. Collectively, our data demonstrate that the combination of sorafenib and HDAC inhibitors kills through activation of the extrinsic pathway, and could represent a useful approach to treat CNS-derived tumors.
HDAC inhibitor; Sorafenib; apoptosis; glioma
AIM: To investigate the inhibitory role and the underlying mechanisms of sorafenib on signal transducer and activator of transcription 3 (STAT3) activity in hepatocellular carcinoma (HCC).
METHODS: Human and rat HCC cell lines were treated with sorafenib. Proliferation and STAT3 dephosphorylation were assessed. Potential molecular mechanisms of STAT3 pathway inhibition by sorafenib were evaluated. In vivo antitumor action and STAT3 inhibition were investigated in an immunocompetent orthotopic rat HCC model.
RESULTS: Sorafenib decreased STAT3 phosphorylation at the tyrosine and serine residues (Y705 and S727), but did not affect Janus kinase 2 (JAK2) and phospha-tase shatterproof 2 (SHP2), which is associated with growth inhibition in HCC cells. Dephosphorylation of S727 was associated with attenuated extracellular signal-regulated kinase (ERK) phosphorylation, similar to the effects of a mitogen-activated protein kinase (MEK) inhibitor U0126, suggesting that sorafenib induced S727 dephosphorylation by inhibiting MEK/ERK signaling. Meanwhile, sorafenib could also inhibit Akt phosphorylation, and both the phosphatidylinositol-3-kinase (PI3K) inhibitor LY294002 and Akt knockdown resulted in Y705 dephosphorylation, indicating that Y705 dephosphorylation by sorafenib was mediated by inhibiting the PI3K/Akt pathway. Finally, in the rat HCC model, sorafenib significantly inhibited STAT3 activity, reducing tumor growth and metastasis.
CONCLUSION: Sorafenib inhibits growth and metastasis of HCC in part by blocking the MEK/ERK/STAT3 and PI3K/Akt/STAT3 signaling pathways, but independent of JAK2 and SHP2 activation.
Hepatocellular carcinoma; Sorafenib; Signal transducer and activator of transcription 3; Extracellular signal regulated kinase; Akt
The objective of this study was to investigate whether the therapeutic activity of sorafenib could be enhanced by combining with OGX-011, an antisense oligodeoxynucleotide (ODN) targeting clusterin, in renal cell carcinoma (RCC).
We investigated the effects of combined treatment with OGX-011 and sorafenib on a human RCC ACHN model both in vitro and in vivo.
Although clusterin expression was increased by sorafenib, additional treatment of ACHN with OGX-011 significantly blocked the upregulation of clusterin induced by sorafenib. Despite the lack of a significant effect on the growth of ACHN, OGX-011 synergistically enhanced the sensitivity to sorafenib, reducing the IC50 by >50%. Apoptotic changes were intensively detected in ACHN after combined treatment with OGX-011 and a sublethal dose of sorafenib, but not either agent alone. Furthermore, this combined treatment resulted in the marked downregulation of phosphorylated Akt and p44/42 mitogen-activated protein kinase in ACHN compared with treatment with either agent alone. In vivo systemic administration of OGX-011 plus sorafenib significantly decreased the ACHN tumour volume compared with control ODN plus sorafenib.
Combined use with OGX-011 may be useful in enhancing the cytotoxic effect of sorafenib on RCC by inducing apoptosis and inactivating major signal transduction pathways.
renal cell carcinoma; sorafenib; clusterin; OGX-011
We investigated the molecular mechanisms underlying the effect of sorafenib and SC-59, a novel sorafenib derivative, on hepatocellular carcinoma (HCC). Sorafenib activated autophagy in a dose- and time-dependent manner in the HCC cell lines PLC5, Sk-Hep1, HepG2 and Hep3B. Sorafenib downregulated phospho-STAT3 (P-STAT3) and subsequently reduced the expression of myeloid cell leukemia-1 (Mcl-1). Inhibition of Mcl-1 by sorafenib resulted in disruption of the Beclin 1-Mcl-1 complex; however, sorafenib did not affect the amount of Beclin 1, suggesting that sorafenib treatment released Beclin 1 from binding with Mcl-1. Silencing of SHP-1 by small interference RNA (siRNA) reduced the effect of sorafenib on P-STAT3 and autophagy. Ectopic expression of Mcl-1 abolished the effect of sorafenib on autophagy. Knockdown of Beclin 1 by siRNA protected the cells from sorafenib-induced autophagy. Moreover, SC-59, a sorafenib derivative, had a more potent effect on cancer cell viability than sorafenib. SC-59 downregulated P-STAT3 and induced autophagy in all tested HCC cell lines. Furthermore, our in vivo
data showed that both sorafenib and SC-59 inhibited tumor growth, downregulated P-STAT3, enhanced the activity of SHP-1 and induced autophagy in PLC5 tumors, suggesting that sorafenib and SC-59 activate autophagy in HCC. In conclusion, sorafenib and SC-59 induce autophagy in HCC through a SHP-1-STAT3-Mcl-1-Beclin 1 pathway.
SC-59; sorafenib; STAT3; HCC
The manuscripts by Park et al.1 and Zhang et al.2 were initially planned as studies to understand the regulation of cell survival in transformed cells treated with sorafenib and vorinostat, and in primary hepatocytes treated with a bile acid+MEK1/2 inhibitor. In both cell systems we discovered that the toxicity of sorafenib and vorinostat or bile acid+MEK1/2 inhibitor exposure depended on the generation of ceramide and the ligand-independent activation of the CD95 death receptor, with subsequent activation of pro-caspase 8. We noted, however, in these systems that, in parallel with death receptor–induced activation of the extrinsic pathway, CD95 signaling also promoted increased phosphorylation of PKR-like endoplasmic reticulum kinase (PERK) and eIF2α, increased expression of ATG5, and increased processing of LC3 and vesicularization of a GFP-LC3 construct. The knockdown of ATG5 expression blocked GFP-LC3 vesicularization and enhanced cell killing. Thus ceramide-CD95 signaling promoted cell death via activation of pro-caspase 8 and cell survival via autophagy. PERK was shown to signal in a switch-hitting fashion; PERK promoted CD95-DISC formation and an eIF2α-dependent reduction in c-FLIP-s levels that were essential for cell killing to proceed, but in parallel it also promoted autophagy that was protective. The death receptor-induced apoptosis and autophagy occur proximal to the receptor rather than the mitochondrion, and the relative flow of death receptor signaling into either pathway may determine cell fate. Finally, death receptor induced apoptosis and autophagy could be potential targets for therapeutic intervention.
Vorinostat; Sorafenib; bile acid; CD95; autophagy; ceramide; cell death; ASMase
The growth of many soft tissue sarcomas is dependent on aberrant growth factor signaling, which promotes their proliferation and motility. With this in mind, we evaluated the effect of sorafenib, a receptor tyrosine kinase inhibitor, on cell growth and apoptosis in sarcoma cell lines of various histological subtypes. We found that sorafenib effectively inhibited cell proliferation in rhabdomyosarcoma, synovial sarcoma and Ewing’s sarcoma with IC50 values <5 μM. Sorafenib effectively induced growth arrest in rhabdomyosarcoma cells, which was concurrent with inhibition of Akt and Erk signaling. Studies of ligand-induced phosphorylation of Erk and Akt in rhabdomyosarcoma cells showed that insulin-like growth factor-1 is a potent activator, which can be blocked by treatment with sorafenib. In vivo sorafenib treatment of rhabdomyosarcoma xenografts had a significant inhibitory effect on tumor growth, which was associated with inhibited vascularization and enhanced necrosis in the adjacent tumor stroma. Our results demonstrate that in vitro and in vivo growth of rhabdomyosarcoma can be suppressed by treatment with sorafenib, and suggests the possibilities of using sorafenib as a potential adjuvant therapy for the treatment of rhabdomyosarcoma.
soft tissue sarcoma; kinase inhibitors; targeted therapy; vascularization
The present studies sought to further understand how the anti-folate pemetrexed and the multi-kinase inhibitor sorafenib interact to kill tumor cells. Sorafenib activated SRC, and via SRC the drug combination activated ERK1/2. Expression of dominant negative SRC or dominant negative MEK1 abolished drug-induced ERK1/2 activation, together with drug-induced autophagy, acidic lysosome formation, and tumor cell killing. Protein phosphatase 2A is an important regulator of the ERK1/2 pathway. Fulvestrant resistant MCF7 cells expressed higher levels of the PP2A inhibitor SET/I2PP2A, had lower endogenous PP2A activity, and had elevated basal ERK1/2 activity compared with their estrogen dependent counterparts. Overexpression of I2PP2A blocked drug-induced activation of ERK1/2 and tumor cell killing. PP2A can be directly activated by ceramide and SET/I2PP2A can be inhibited by ceramide. Inhibition of the de novo ceramide synthase pathway blocked drug-induced ceramide generation, PP2A activation and tumor cell killing. Collectively these findings demonstrate that ERK1/2 plays an essential role downstream of SRC in pemetrexed and sorafenib lethality and that PP2A plays an important role in regulating this process.
ERK; I2PP2A; PP2A; SRC; autophagy; ceramide; pemetrexed; sorafenib
Despite conventional treatment strategies glioblastoma, the most common malignant primary brain has a bad prognosis with median survival times of 12-15 month. In this study, the efficacy of sorafenib (Nexavar, BAY43-9006), a multikinase inhibitor, on glioblastoma cells was evaluated both in vitro and in vivo. Treatment of established or patient-derived glioblastoma cells with low concentrations of sorafenib caused a dramatic dose dependent inhibition of proliferation (IC50, 1.5 uM) and induction of apoptosis and autophagy. Sorafenib inhibited phosphorylation of signal transducer and activator of transcription 3 (Stat3) and expression of cyclins, D and E. In contrast, AKT was not modulated by sorafenib. Most important, systemic delivery of Sorafenib was well tolerated, and significantly suppressed intracranial glioma growth via inhibition of cell proliferation, induction of apoptosis and autophagy, and reduction of angiogenesis. Furthermore, intracranial growth inhibition by sorafenib was accompanied by a significant reduction in ph-Stat3 (Tyr 705) levels. In summary, sorafenib has potent anti-glioma activity in vitro and in vivo.
Glioma; Sorafenib; Stat3; apoptosis; autophagy
Purpose. It has been reported that Th2 cytokines downregulate antitumor immunity, while activation of type T cells promotes antitumor immunity. The aim of this paper was to evaluate host immunity in liver cirrhosis (LC) patients with advanced hepatocellular carcinoma (aHCC) receiving sorafenib therapy. Methods. Forty-five adult Japanese LC patients received sorafenib for aHCC between 2009 and 2011 at our hospital. Sorafenib was administered at a dose of 200–800 mg/day for 4 weeks. Blood samples were collected before and after treatment. Results. Eleven patients were treated with sorafenib at 200 mg/day (200 group), 27 patients received sorafenib at 400 mg/day (400 group), and 7 patients were given sorafenib at 800 mg/day (800 group). There was no significant change in the percentage of Th1 cells after treatment in any group. However, the percentages of Th2 cells and regulatory T cells were significantly decreased after treatment in the 400 group and 800 group compared with before treatment, although there was no significant change after treatment in the 200 group. Conclusions. These results indicate that treatment with sorafenib might induce Th1 dominance and prevent the escape of tumor cells from the host immune system in LC patients with aHCC.
Sorafenib is an oral multitargeted tyrosine and serine/threonine kinase inhibitor
approved for the treatment of advanced renal cell and hepatocellular carcinoma.
An understanding of its dose–toxicity relationship has paved the way for
trials seeking to enhance its clinical activity through the exploration of
alternative dosing strategies. In this article, we review the
dose–toxicity relationship of sorafenib observed during its phase I and
early phase II testing, explore its toxicity profile at the recommended dose and
schedule, discuss the evidence for dose escalation to higher levels, and examine
the preliminary evidence for clinical activity of this strategy. Owing to a
temporal relationship between toxicity and dose, it may be possible in select
patients to escalate sorafenib to doses beyond those currently employed.
However, because of the potential for increased toxicity, sorafenib dose
escalation should currently be performed only in the context of a clinical
dose–response relationship; drug; maximum tolerated dose; toxicity; sorafenib
Aberrant Ras/Raf/MAPK and PI3K/AKT/mTOR signaling pathways are found in hepatocellular carcinoma (HCC). This study reports how sorafenib (a multi-kinase inhibitor) and PI-103 (a dual PI3K/mTOR inhibitor) alone and in combination inhibit the proliferation of the HCC cell line, Huh7.
Materials and Methods
Huh7 proliferation was assayed by 3H-thymidine incorporation and by MTT assay. Western blot was used to detect phosphorylation of the key enzymes in the Ras/Raf and PI3K pathways.
Sorafenib and PI-103, as single agents, inhibited Huh7 proliferation and epidermal growth factor (EGF)-stimulated Huh7 proliferation in a dose-dependent fashion; the combination of sorafenib and PI-103 produced synergistic effects. EGF increased phosphorylation of MEK and ERK, key Ras/Raf downstream signaling proteins; this activation was inhibited by sorafenib. However, sorafenib, as a single agent, increased AKT (Ser473) and mTOR phosphorylation. EGF-stimulated activation of PI3K/AKT/mTOR pathway components was inhibited by PI-103. PI-103 is a potent inhibitor of AKT (Ser473) phosphorylation; in contrast, rapamycin stimulated AKT(Ser473) phosphorylation. It was found that PI-103, as a single agent, stimulated MEK and ERK phosphorylation. However, the combination of sorafenib and PI-103 caused inhibition of all the tested kinases in the Ras/Raf and PI3K pathways.
The combination of sorafenib and PI-103 can significantly inhibit EGF-stimulated Huh7 proliferation by blocking both Ras/Raf/MAPK and PI3K/AKT/mTOR pathways.
Epidermal growth factor; PI-103; rapamycin; mTOR complex 1; mTOR complex 2; negative feedback loop
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.
Sorafenib is an orally available kinase inhibitor with activity at Raf, PDGFβ and VEGF receptors that is licensed for the treatment of advanced renal cell carcinoma (RCC) and hepatocellular carcinoma (HCC). Current evidence-based post-nephrectomy management of individuals with localized RCC consists of surveillance-based follow up. The SORCE trial is designed to investigate whether treatment with adjuvant sorafenib can reduce recurrence rates in this cohort.
Here we report an idiosyncratic reaction to sorafenib resulting in fatal hepatotoxicity and associated renal failure in a 62 year-old man treated with sorafenib within the SORCE trial.
This is the first reported case of sorafenib exposure associated fatal toxicity in the adjuvant setting and highlights the unpredictable adverse effects of novel adjuvant therapies.
Sorafenib; Hepatotoxicity; Adjuvant; SORCE; RCC; DILI
The use of sorafenib in combination with selected chemotherapies in patients with advanced breast cancer is examined and the incidence, prevention, and management of hand–foot skin reaction are considered.
Current combination therapies for advanced breast cancer provide a modest survival benefit but with greater toxicity than with monotherapies. New combinations are needed that improve the efficacy of current treatments and have acceptable tolerability profiles. Recent clinical trials have assessed the efficacy and safety of the multikinase inhibitor sorafenib in combination with common treatments for advanced breast cancer. Sorafenib has both antiangiogenic and antiproliferative activities and is indicated for patients with unresectable hepatocellular and advanced renal cell carcinoma. Generally, sorafenib is associated with manageable, non–life-threatening adverse events. One of the more common adverse events seen with sorafenib is hand–foot skin reaction, a dermatologic toxicity usually localized to the pressure points of the palms and soles. Although hand–foot skin reaction is reversible and not life threatening, it can have a significant impact on a patient's quality of life and may necessitate dose modification. Moreover, sorafenib is being evaluated in combination with breast cancer treatments that are associated with a similar dermatologic toxicity (e.g., capecitabine-induced hand–foot syndrome). This review looks at the use of sorafenib in combination with selected chemotherapies in patients with advanced breast cancer and considers the incidence, prevention, and management of hand–foot skin reaction.
Breast cancer; Hand–foot skin reaction; Hand–foot syndrome; Sorafenib; Capecitabine; Paclitaxel
Glioblastoma is the most common type of primary brain tumor and is rapidly progressive with few treatment options. Here, we report that sorafenib (≤ 10 μM) inhibited cell proliferation and induced apoptosis in two established cell lines (U87, U251) and two primary cultures (PBT015, PBT022) from human glioblastomas. Effects of sorafenib on these tumor cells were associated with inhibiting phosphorylated STAT3 (Tyr705). Expression of a constitutively activated STAT3 mutant partially blocked the effects of sorafenib, consistent with a role for STAT3 inhibition in the response to sorafenib. Phosphorylated JAK1 was inhibited in U87 and U251 cells, while phosphorylated JAK2 was inhibited in primary cultures. Sodium vanadate, a general inhibitor of protein tyrosine phosphatases, blocked the inhibition of phosphorylation of STAT3 (Tyr705) induced by sorafenib. These data indicate that the inhibition of STAT3 activity by sorafenib involves both inhibition of upstream kinases (JAK1 and JAK2) of STAT3 and increased phosphatase activity. Phosphorylation of AKT was also reduced by sorafenib. In contrast, MAPK were not consistently inhibited by sorafenib in these cells. Two key cyclins (D and E) and the anti-apoptotic protein Mcl-1 were down-regulated by sorafenib in both cell lines and primary cultures. Our data suggest that inhibition of STAT3 signaling by sorafenib contributes to growth arrest and induction of apoptosis in glioblastoma cells. These findings provide a rationale for potential treatment of malignant gliomas with sorafenib.
Sorafenib; glioblastoma; STAT3; apoptosis; proliferation
Sorafenib, a multi-tyrosine kinase inhibitor, is a standard treatment for advanced hepatocellular carcinoma (HCC). The present study was undertaken to determine whether the growth and metastasis of HCC were influenced in mice receiving sorafenib prior to implantation with tumors, and to investigate the in-vivo and in-vitro effect of sorafenib on natural killer (NK) cells. In sorafenib-pretreated BALB/c nu/nu mice and C57BL/6 mice, tumor growth was accelerated, mouse survival was decreased, and lung metastasis was increased. However, the depletion of NK1.1+ cells in C57BL/6 mice eliminated sorafenib-mediated pro-metastatic effects. Sorafenib significantly reduced the number of NK cells and inhibited reactivity of NK cells against tumor cells, in both tumor-bearing and tumor-free C57BL/6 mice. Sorafenib down-regulated the stimulatory receptor CD69 in NK cells of tumor-bearing mice, but not in tumor-free mice, and inhibited proliferation of NK92-MI cells, which is associated with the blocking of the PI3K/AKT pathway, and inhibited cytotoxicity of NK cells in response to tumor targets, which was due to impaired ERK phosphorylation. These results suggest immunotherapeutic approaches activating NK cells may enhance the therapeutic efficacy of sorafenib in HCC patients.
Malignant pleural mesothelioma (MPM) is an aggressive, rapidly progressive malignancy without effective therapy. We evaluate sorafenib efficacy and impact on the cellular pro-survival machinery in vitro, efficacy of sorafenib as monotherapy and in combination with the naturally occurring death receptor agonist, TRAIL using human MPM cell lines, MSTO-211H, M30, REN, H28, H2052 and H2452. In vitro studies of the six MPM lines demonstrated single agent sensitivity to the multikinase inhibitor sorafenib and resistance to TRAIL. H28 and H2452 demonstrated augmented apoptosis with the addition of TRAIL to sorafenib in vitro. Treated cell lines demonstrated sorafenib-induced rapid dephosphorylation of AKT followed shortly by near complete dephosphorylation of the constitutively phosphorylated ERK1/2. Sorafenib therapy also decreased phosphorylation of B-Raf and mTOR in several cell lines. Within 3 h of sorafenib treatment, a number of known pro-survival molecules were dephosphorylated and/or downregulated in expression including MCL-1L, c-FLIPL, survivin and cIAP 1. These changes and eventual cell death did not elicit significant caspase-3 activation or PARP cleavage and pretreatment with the pan-caspase inhibitor, Z-VAD-FMK, did not block sorafenib efficacy but did block the effect of TRAIL monotherapy. Pre-treatment with Z-VAD-FMK did not block the synergistic effect of TRAIL and sorafenib in H28. In summary, single agent treatment with sorafenib results in widespread inhibition of the pro-survival machinery in vitro leading to cell death via a primarily caspase-independent mechanism. Combining sorafenib therapy with TRAIL, may be useful in order to provide a more efficient death signal and this synergistic effect appears to be caspase-independent. Pilot in vivo data demonstrates promising evidence of therapeutic efficacy in human tumor bearing xenograft nu/nu mice. We document single agent activity of sorafenib against MPM, unravel novel effects of sorafenib on anti-apoptotic signaling mediators, and suggest the combination of sorafenib plus TRAIL as possible therapy for clinical testing in MPM.
mesothelioma; cancer therapy; cell death; sorafenib; MCL-1; imaging; TRAIL; caspase-independent
The multi-kinase inhibitor Sorafenib, is the first oral agent to show activity against human hepatocellular carcinoma (HCC). Apoptosis has been shown to be induced in HCC by several agents, including Sorafenib, as well as by the naturally occurring K vitamins (VKs). Since few non toxic agents have activity against HCC growth, we evaluated the activity of Sorafenib and K vitamins, both independently and together on the growth in vitro and in vivo of HCC cells. We found that when VK was combined with Sorafenib, the concentration of Sorafenib required for growth inhibition was substantially reduced. Conversely, VK enhanced Sorafenib effects in several HCC cell lines on growth inhibition. Growth could be inhibited at doses of VK plus Sorafenib that were ineffective with either agent alone,using vitamins K1, K2 and K5. Combination VK1 plus Sorafenib induced apoptosis on FACS, TUNEL staining and caspase activation. Phospho-ERK levels were decreased, as was Mcl-1, an ERK target. Sorafenib alone inhibited growth of transplantable HCC in vivo. At sub-effective Sorafenib doses in vivo, addition of VK1 caused major tumor regression, with decreased phospho-ERK and Mcl-1 staining. Thus, combination VK1 plus Sorafenib strongly induced growth inhibition and apoptosis in rodent and human HCC and inhibited the RAF/MEK/ERK pathway. VK1 alone activated PKA, a mediator of inhibitory Raf phosphorylation. Thus, each agent can antagonize Raf; Sorafenib as a direct inhibitor and VK1 through inhibitory Raf phosphorylation. Since both agents are available for human use, the combination has potential for improving Sorafenib effects in HCC.
Sorafenib; Vitamin K; Apoptosis; ERK; HCC