The monoclonal antibody CH12 enhances the sorafenib-mediated growth inhibition of hepatocellular carcinoma xenografts expressing epidermal growth factor receptor variant III

Ramucirumab combination with sorafenib enhances the inhibitory effect of sorafenib on HepG2 cancer cells

Sorafenib, an oral multiple kinase inhibitor, is the standardized treatment for hepatocellular carcinoma (HCC). One strategy to improve HCC therapy is to combine agents that target key signaling pathways. In this study we set out to investigate the effect of combining sorafenib with either bevacizumab (anti-VEGF), panitumumab (anti-EGFR) or ramucirumab (anti-VEGFR2) on HepG2 cancer cell line with the aim of improving efficacy and possibility of therapeutic dose reduction of sorafenib.: HepG2 cancer cell line was treated with sorafenib alone or in combination with either bevacizumab, panitumumab or ramucirumab. Cell proliferation; apoptosis and cell cycle distribution; gene expression of VEGFR2, EGFR, MMP-9 and CASPASE3; the protein levels of pVEGFR2 and pSTAT3 and the protein expression of CASPASE3, EGFR and VEGFR2 were determined. Combined treatments of sorafenib with ramucirumab or panitumumab resulted in a significant decrease in sorafenib IC₅₀. Sorafenib combination with ramucirumab or bevacizumab resulted in a significant arrest in pre-G and G0/G1 cell cycle phases, significantly induced apoptosis and increased the relative expression of CASPASE3 and decreased the anti-proliferative and angiogenesis markers´ MMP-9 and pVEGFR2 or VEGFR2 in HepG2 cells. A significant decrease in the levels of pSTAT3 was only detected in case of sorafenib-ramucirumab combination. The combined treatment of sorafenib with panitumumab induced a significant arrest in pre-G and G2/M cell cycle phases and significantly decreased the relative expression of EGFR and MMP-9. Sorafenib-ramucirumab combination showed enhanced apoptosis, inhibited proliferation and angiogenesis in HepG2 cancer cells. Our findings suggest that ramucirumab can be a useful as an adjunct therapy for improvement of sorafenib efficacy in suppression of HCC.

Morphine promotes microglial activation by upregulating the EGFR/ERK signaling pathway

Although they represent the cornerstone of analgesic therapy, opioids, such as morphine, are limited in efficacy by drug tolerance, hyperalgesia and other side effects. Activation of microglia and the consequent production of proinflammatory cytokines play a key pathogenic role in morphine tolerance, but the exact mechanisms are not well understood. This study aimed to investigate the regulatory mechanism of epidermal growth factor receptor (EGFR) on microglial activation induced by morphine in mouse microglial BV-2 cells. In this research, BV-2 cells were stimulated with morphine or pretreated with AG1478 (an inhibitor of EGFR). Expression levels of cluster of differentiation molecule 11b (CD11b), EGFR, and phospho-EGFR were detected by immunofluorescence staining. Cell signaling was assayed by Western blot. The migration ability of BV-2 cells was tested by Transwell assay. The production of interleukin-1beta (IL-1β) and tumor necrosis factor-alpha (TNF-α) in the cell supernatant was determined by ELISA. We observed that the expression of CD11b induced by morphine was increased in a dose- and time- dependent manner in BV-2 cells. Phosphorylation levels of EGFR and ERK1/2, migration of BV-2 cells, and production of IL-1β and TNFα were markedly enhanced by morphine treatment. The activation, migration, and production of proinflammatory cytokines in BV-2 cells were inhibited by blocking the EGFR signaling pathway with AG1478. The present study demonstrated that the EGFR/ERK signaling pathway may represent a novel pharmacological strategy to suppress morphine tolerance through attenuation of microglial activation.

Activation of the spinal EGFR signaling pathway in a rat model of cancer-induced bone pain with morphine tolerance

Cancer-induced bone pain (CIBP) is considered to be one of the most difficult pain conditions to treat. Morphine, an analgesic drug, is widely used in clinical practice, and long-term use of morphine can lead to drug tolerance. Recent reports have suggested that inhibitors of epidermal growth factor receptor (EGFR) may have analgesic effects in cancer patients suffering from pain. Therefore, we sought to determine whether EGFR signaling was involved in morphine tolerance (MT) in a rat model of cancer-induced bone pain. In this study, Walker 256 mammary gland carcinoma cells were inoculated into the tibias of rats to provoke cancer-induced bone pain. Then, morphine was intrathecally administered twice daily for seven consecutive days to induce drug tolerance. We observed sustained increased in the protein levels of EGFR, p-EGFR, ERK1/2, and p-ERK1/2 during the development of morphine tolerance in rats with cancer-induced bone pain by western blotting. The EGFR level was significantly increased in the MT and CIBP + MT groups, and EGFR was colocalized with markers of microglia and neurons in the spinal cords of rats. Inhibition of EGFR by a small molecule inhibitor markedly attenuated the degree of morphine tolerance and decreased the number of microglia, and the protein levels of EGFR, p-EGFR, ERK1/2, and p-ERK1/2 were also reduced. In summary, our results suggest that the activation of the EGFR signaling pathway in spinal microglia plays an important modulatory role in the development of morphine tolerance and that inhibition of EGFR may provide a new therapeutic option for cancer-induced bone pain.

miRNA-574-3p inhibits metastasis and chemoresistance of epithelial ovarian cancer (EOC) by negatively regulating epidermal growth factor receptor (EGFR)

BACKGROUND

This current study explored the role of miRNA-574-3p and the related molecular mechanisms in epithelial ovarian cancer (EOC).

METHODS

Tissues of ovarian cancer patients were applied to explore the correlation between miRNA-574-3p and EOC. The role of miRNA-574-3p in migration, invasion and chemoresistance of EOC cells was evaluated by overexpression and suppression of miRNA-574-3p in SKOV3 and CAOV3 cells. For the sake of exploring how miRNA-574-3p regulated tumor migration, invasion and chemoresistance of EOC cells, we detected several related molecular expressions and activities of signaling pathways.

RESULTS

Overexpression of epidermal growth factor receptor (EGFR) was correlated with downregulation of miR-574-3p in EOC tissues. Overexpression of miRNA-574-3p in EOC cells led to inhibition of cell migration as well as invasion, and it significantly promoted the sensitivities of EOC cells to paclitaxel and cisplatin. Molecular experiments showed miR-574-3p inhibited activation of AKT, FAK and c-Src, as well as MMP-9 expression via targeting EGFR.

CONCLUSION

Taken together, these data demonstrated that miRNA-574-3p inhibits both tumor metastasis and chemoresistance in EOC via targeting EGFR. Thus, targeting miRNA-574-3p may become a potential molecular method for EOC.

Combined Antitumor Effects of Sorafenib and GPC3-CAR T Cells in Mouse Models of Hepatocellular Carcinoma

Our previous study indicated that GPC3-targeted chimeric antigen receptor (CAR) T cell therapy has a high safety profile in patients with hepatocellular carcinoma (HCC). However, the response rate requires further improvement. Here, we analyzed the combined effect of GPC3-CAR T cells and sorafenib in both immunocompetent and immunodeficient mouse models of hepatocellular carcinoma. In immunocompetent mouse model, mouse CAR (mCAR) T cells induced regression of small tumors (approximately 130 mm³ tumor volume) but had no effect on large, established tumors (approximately 400 mm³ tumor volume). Sorafenib, at a subpharmacologic but not a pharmacologic dose, augmented the antitumor effects of mCAR T cells, in part by promoting IL12 secretion in tumor-associated macrophages (TAMs) and cancer cell apoptosis. In an immunodeficient mouse model, both subpharmacologic and pharmacologic doses of sorafenib had limited impacts on the function of human CAR (huCAR) T cells in vitro and showed synergistic effects with huCAR T cells in vivo, which can at least partially be ascribed to the upregulated tumor cell apoptosis induced by the combined treatment. Thus, this study applied two of the most commonly used mouse models for CAR T cell research and demonstrated the clinical potential of combining sorafenib with GPC3-targeted CAR T cells against HCC.

Growth suppression of colorectal cancer expressing S492R EGFR by monoclonal antibody CH12

Colorectal cancer (CRC) is a common malignant tumor in the digestive tract, and 30%-85% of CRCs express epidermal growth factor receptors (EGFRs). Recently, treatments using cetuximab, also named C225, an anti-EGFR monoclonal antibody, for CRC have been demonstrated to cause an S492R mutation in EGFR. However, little is known about the biological function of S492R EGFR. Therefore, we attempted to elucidate its biological function in CRC cells and explore new treatment strategies for this mutant form. Our study indicated that EGFR and S492R EGFR accelerate the growth of CRC cells in vitro and in vivo and monoclonal antibody CH12, which specifically recognizes an EGFR tumor-specific epitope, can bind efficiently to S492R EGFR. Furthermore, mAb CH12 showed significantly stronger growth suppression activities and induced a more potent antibody-dependent cellular cytotoxicity effect on CRC cells bearing S492R EGFR than mAb C225. mAb CH12 obviously suppressed the growth of CRC xenografts with S492R EGFR mutations in vivo. Thus, mAb CH12 may be a promising therapeutic agent in treating patients with CRC bearing an S492R EGFR mutation.

Synergistic effect of ursodeoxycholic acid on the antitumor activity of sorafenib in hepatocellular carcinoma cells via modulation of STAT3 and ERK

Sorafenib has been approved for the treatment of advanced stage hepatocellular carcinoma but has limited efficacy. Ursodeoxycholic acid exerts cytoprotective activities in hepatocytes and is believed to suppress tumorigenesis through cell cycle arrest and induction of apoptosis. The present study examined whether co-treatment with ursodeoxycholic acid has a synergistic effect on the antitumor activity of sorafenib in hepatocellular carcinoma cells. Notably, co-treatment with both agents more effectively inhibited cell proliferation than sorafenib or ursodeoxycholic acid alone. Furthermore, co-treatment inhibited the phosphorylation of signal transducer and activator of transcription 3 (STAT3) and activated extracellular signal-regulated kinase (ERK), a mitogen-activated protein kinase, accompanied by excessive intracellular reactive oxygen species generation in hepatocellular carcinoma cells. Thus, chemotherapy with sorafenib and ursodeoxycholic combination may be efficacious in hepatocellular carcinoma by inhibiting cell proliferation and inducing apoptosis through reactive oxygen species-dependent activation of ERK and dephosphorylation of STAT3. The present findings may represent a promising therapeutic strategy for patients with advanced hepatocellular carcinoma.

Sorafenib and gadolinium co-loaded liposomes for drug delivery and MRI-guided HCC treatment

To improve the poor water solubility of sorafenib and to monitor its distribution and the early feedback effects on its in vivo treatment efficacy in a precise manner, sorafenib (SF) and gadolinium (Gd) co-loaded liposomes (SF/Gd-liposomes) were prepared. The simultaneous imaging and therapy efficacies of the SF/Gd-liposomes were tested. The solubility of SF in SF/Gd-liposomes was significantly increased from 0.21 μg/mL to 250 μg/mL. The imaging capability of SF/Gd-liposomes were tested by in-vitro and the in-vivo imaging ability tests and the results confirmed that SF/Gd-liposomes could be served as an effective contrast agent. The design of SF/Gd-liposomes allowed the MRI-guided in vivo visualization of the delivery and biodistribution of liposome. In the in vivo antitumor studies, SF/Gd-liposomes had better antitumor effects in H22 tumor-bearing mice than SF solution (oral or i.v. administration) (P<0.05). These findings indicated that the SF/Gd-liposomes could be used as the promising nano-carriers for the MRI-guided in vivo visualization of the delivery and HCC treatment.

EGFR Signaling in Liver Diseases

The epidermal growth factor receptor (EGFR) is a transmembrane receptor tyrosine kinase that is activated by several ligands leading to the activation of diverse signaling pathways controlling mainly proliferation, differentiation, and survival. The EGFR signaling axis has been shown to play a key role during liver regeneration following acute and chronic liver damage, as well as in cirrhosis and hepatocellular carcinoma (HCC) highlighting the importance of the EGFR in the development of liver diseases. Despite the frequent overexpression of EGFR in human HCC, clinical studies with EGFR inhibitors have so far shown only modest results. Interestingly, a recent study has shown that in human HCC and in mouse HCC models the EGFR is upregulated in liver macrophages where it plays a tumor-promoting function. Thus, the role of EGFR in liver diseases appears to be more complex than what anticipated. Further studies are needed to improve the molecular understanding of the cell-specific signaling pathways that control disease development and progression to be able to develop better therapies targeting major components of the EGFR signaling network in selected cell types. In this review, we compiled the current knowledge of EGFR signaling in different models of liver damage and diseases, mainly derived from the analysis of HCC cell lines and genetically engineered mouse models (GEMMs).

Cancer subclonal genetic architecture as a key to personalized medicine

The future of personalized oncological therapy will likely rely on evidence-based medicine to integrate all of the available evidence to delineate the most efficacious treatment option for the patient. To undertake evidence-based medicine through use of targeted therapy regimens, identification of the specific underlying causative mutation(s) driving growth and progression of a patient's tumor is imperative. Although molecular subtyping is important for planning and treatment, intraclonal genetic diversity has been recently highlighted as having significant implications for biopsy-based prognosis. Overall, delineation of the clonal architecture of a patient's cancer and how this will impact on the selection of the most efficacious therapy remain a topic of intense interest.

Sorafenib in liver function impaired advanced hepatocellular carcinoma

OBJECTIVE

To explore the efficacy and safty of sorafenib in Child-Pugh class B to class C hepatocellular carcinoma (HCC).

METHODS

In this three-center open-label study from November 2011 to May 2013, we randomly assigned 189 patients with advanced Child-Pugh class B or C HCC patients into two groups, one group with 95 patient to receive sorafenib (400 mg a time, twice a day) and the other group with 94 patients to receive best supportive care. The primary end points were progression-free survival and overall survival.

RESULTS

The median progression-free survival was 2.2 months and 1.9 months in the sorafenib group and best supportive care group respectively (Hazard ratio in the sorafenib group, 0.55; 95% confidence interval, 0.40-0.75; P=0.002). The median overall survival was 4.0 months and 3.5 months in the sorafenib group and best supportive care group respectively (Hazard ratio in the sorafenib group, 0.48; 95% confidence interval, 0.35-0.68; P<0.001). The main adverse effect of sorafenib was rash and acne of the skin (in 51.7% patients). The incidences of severe rash, diarrhea, and dry skin were 5.6%, 5.6%, and 2.2% in the sorafenib group. One patient reached partial response in the sorafenib group.

CONCLUSIONS

Sorafenib is safe in patients with liver function impaired advanced HCC. It is effective in terms of progression-free survival and overall survival compared with best supportive care. Liver functions are the important predictive factors.

An EpCAM/CD3 bispecific antibody efficiently eliminates hepatocellular carcinoma cells with limited galectin-1 expression

There have been several studies suggesting that cancer stem cells (CSCs) contribute to the high rates of recurrence and resistance to therapies observed in hepatocellular carcinoma (HCC). Epithelial cell adhesion molecule (EpCAM) has been demonstrated to be a biomarker of CSCs and a potential therapeutic target in HCC. Here, we prepared two anti-EpCAM monoclonal antibodies (1H8 and 2F2) and an anti-EpCAM bispecific T cell engager (BiTE) 1H8/CD3, which was derived from 1H8, and used them to treat HCC in vitro and in vivo. The results demonstrated that all of the developed anti-EpCAM antibodies specifically bound to EpCAM. Neither anti-EpCAM monoclonal antibody had obvious anti-HCC activities in vitro or in vivo. However, anti-EpCAM BiTE 1H8/CD3 induced strong peripheral blood mononuclear cell-dependent cellular cytotoxicity in Huh-7 and Hep3B cells but not EpCAM-negative SK-Hep-1 cells. Notably, 1H8/CD3 completely inhibited the growth of Huh-7 and Hep3B xenografts in vivo. Treatment of the Huh-7 HCC xenografts with 1H8/CD3 significantly suppressed tumor proliferation and reduced the expression of most CSC biomarkers. Intriguingly, galectin-1 (Gal-1) overexpression inhibited 1H8/CD3-induced lymphocytotoxicity in HCCs while knockdown of Gal-1 increased the lymphocytotoxicity. Collectively, these results indicate that anti-EpCAM BiTE 1H8/CD3 is a promising therapeutic agent for HCC treatment. Gal-1 may contribute to the resistance of HCC cells to 1H8/CD3-induced lysis.

Galectin-1 overexpression promotes progression and chemoresistance to cisplatin in epithelial ovarian cancer

This study was performed to investigate the role of galectin-1 (Gal-1) in epithelial ovarian cancer (EOC) progression and chemoresistance. Tissue samples from patients with EOC were used to examine the correlation between Gal-1 expression and clinical stage of EOC. The role of Gal-1 in EOC progression and chemoresistance was evaluated in vitro by siRNA-mediated knockdown of Gal-1 or lentivirus-mediated overexpression of Gal-1 in EOC cell lines. To elucidate the molecular mechanisms underlying Gal-1-mediated tumor progression and chemoresistance, the expression and activities of some signaling molecules associated with Gal-1 were analyzed. We found overexpression of Gal-1 in advanced stages of EOC. Knockdown of endogenous Gal-1 in EOC cells resulted in the reduction in cell growth, migration, and invasion in vitro, which may be caused by Gal-1's interaction with H-Ras and activation of the Raf/extracellular signal-regulated kinase (ERK) pathway. Additionally, matrix metalloproteinase-9 (MMP-9) and c-Jun were downregulated in Gal-1-knockdown cells. Notably, Gal-1 overexpression could significantly decrease the sensitivities of EOC cells to cisplatin, which might be ascribed to Gal-1-induced activation of the H-Ras/Raf/ERK pathway and upregulation of p21 and Bcl-2. Taken together, the results suggest that Gal-1 contributes to both tumorigenesis and cisplatin resistance in EOC. Thus, Gal-1 is a potential therapeutic target for EOC.

The EGFR signalling system in the liver: from hepatoprotection to hepatocarcinogenesis

The liver displays an outstanding wound healing and regenerative capacity unmatched by any other organ. This reparative response is governed by a complex network of inflammatory mediators, growth factors and metabolites that are set in motion in response to hepatocellular injury. However, when liver injury is chronic, these regenerative mechanisms become dysregulated, facilitating the accumulation of genetic alterations leading to unrestrained cell proliferation and the development of hepatocellular carcinoma (HCC). The epidermal growth factor receptor (EGFR or ErbB1) signaling system has been identified as a key player in all stages of the liver response to injury, from early inflammation and hepatocellular proliferation to fibrogenesis and neoplastic transformation. The EGFR system engages in extensive crosstalk with other signaling pathways, acting as a true signaling hub for other growth factors, cytokines and inflammatory mediators. Here, we briefly review essential aspects of the biology of the EGFR, the other ErbB receptors, and their ligands in liver injury, regeneration and HCC development. Some aspects of the preclinical and clinical experience with EGFR therapeutic targeting in HCC are also discussed.

EGFRvIII mediates hepatocellular carcinoma cell invasion by promoting S100 calcium binding protein A11 expression

Epidermal growth factor receptor (EGFR) is frequently aberrantly expressed in cancer, and abnormal signalling downstream of this receptor contributes to tumour growth. EGFR variant III (EGFRvIII) is the most commonly altered form of EGFR and contains a truncated ligand-binding domain. Aberrant signalling downstream of this receptor contributes to tumour invasion. We previously reported that EGFRvIII can promote hepatocellular carcinoma (HCC) invasion. However, little is known concerning the mechanisms underlying EGFRvIII-mediated increases in cell motility and invasion in HCC. In this study, we observed that S100A11 was significantly upregulated in Huh-7 cells that overexpressed EGFRvIII. Moreover, S100A11 expression was elevated in HCC tissue samples (68.6%; 35/51), and this elevation was correlated with EGFRvIII expression (p = 0.0020; n = 20). Furthermore, the overexpression of S100A11 can promote HCC cell invasiveness, whereas siRNA against S100A11 can suppress the invasiveness of HCC cells stably transfected with EGFRvIII. Additionally, STAT3 inhibitors can block S100A11 expression and S100A11 promoter activity in HCC cells with stable overexpression of EGFRvIII. Furthermore, mutation in STATx binding sites could abolish the S1000A11 promoter activity stimulation by EGFRvIII. Taken together, the results demonstrate that the EGFRvIII-STAT3 pathway promotes cell migration and invasion by upregulating S100A11.

Purified vitexin compound 1 inhibits growth and angiogenesis through activation of FOXO3a by inactivation of Akt in hepatocellular carcinoma

Vitexins, isolated from the seeds of the Chinese herb Vitex negundo, is known to exert antitumor activity in cancer xenograft models and cell lines. The aim of the current study was to examine whether the Akt/forkhead box protein O3a (FOXO3a) pathway mediates the biological effects of purified vitexin compound 1 (VB-1) in hepatocellular carcinoma (HCC) cells. The effect of VB-1 on the viability of the HCC cell lines HepG2, Hep3B, Huh-7 and the human embryonic liver cells L-02 was investigated using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Growth inhibition was assessed by clonogenic assay, and cell cycle arrest was investigated using flow cytometry. Inhibition of angiogenesis was evaluated using a matrigel in vitro HUVEC tube formation assay. The effects on the Akt/FOXO3a pathway were detected by western blotting. VB-1 suppressed the proliferation of HepG2, Hep3B, Huh-7 cells, but had little effect on L-02 cells. VB-1 inhibited anchorage-dependent and -independent HepG2 cell growth in a concentration-dependent manner by induction of cell cycle arrest at G1/G0. VB-1 also reduced the secretion of vascular endothelial growth factor (VEGF), resulting in the inhibition of endothelial tube formation. Phosphorylated Akt and its downstream effector FOXO3a were downregulated in VB-1-treated HepG2 cells. Knockdown of Akt1 by small interfering RNA (siRNA) enhanced growth inhibition, and silencing FOXO3a by siRNA attenuated this action. VB-1 inhibited growth and induced cell cycle arrest at G1/G0 by regulating the Akt/FOXO3a pathway. The findings suggested that VB-1 is a potentially promising candidate for the treatment of HCC.

Therapeutic modulators of STAT signalling for human diseases

The signal transducer and activator of transcription (STAT) proteins have important roles in biological processes. The abnormal activation of STAT signalling pathways is also implicated in many human diseases, including cancer, autoimmune diseases, rheumatoid arthritis, asthma and diabetes. Over a decade has passed since the first inhibitor of a STAT protein was reported and efforts to discover modulators of STAT signalling as therapeutics continue. This Review discusses the outcomes of the ongoing drug discovery research endeavours against STAT proteins, provides perspectives on new directions for accelerating the discovery of drug candidates, and highlights the noteworthy candidate therapeutics that have progressed to clinical trials.

Overcoming intratumor heterogeneity of polygenic cancer drug resistance with improved biomarker integration

Improvements in technology and resources are helping to advance our understanding of cancer-initiating events as well as factors involved with tumor progression, adaptation, and evasion of therapy. Tumors are well known to contain diverse cell populations and intratumor heterogeneity affords neoplasms with a diverse set of biologic characteristics that can be used to evolve and adapt. Intratumor heterogeneity has emerged as a major hindrance to improving cancer patient care. Polygenic cancer drug resistance necessitates reconsidering drug designs to include polypharmacology in pursuit of novel combinatorial agents having multitarget activity to overcome the diverse and compensatory signaling pathways in which cancer cells use to survive and evade therapy. Advances will require integration of different biomarkers such as genomics and imaging to provide for more adequate elucidation of the spatially varying location, type, and extent of diverse intratumor signaling molecules to provide for a rationale-based personalized cancer medicine strategy.

Epidermal growth factor receptor as a therapeutic target in glioblastoma

Glioblastoma represents one of the most challenging problems in neurooncology. Among key elements driving its behavior is the transmembrane epidermal growth factor receptor family, with the first member epidermal growth factor receptor (EGFR) centered in most studies. Engagement of the extracellular domain with a ligand activates the intracellular tyrosine kinase (TK) domain of EGFR, leading to autophosphorylation and signal transduction that controls proliferation, gene transcription, and apoptosis. Oncogenic missense mutations, deletions, and insertions in the EGFR gene are preferentially located in the extracellular domain in glioblastoma and cause constitutive activation of the receptor. The mutant EGFR may also transactivate other cell surface molecules, such as additional members of the EGFR family and the platelet-derived growth factor receptor, which ignite signaling cascades that synergize with the EGFR-initiated cascade. Because of the cell surface location and increased expression of the receptor along with its important biological function, EGFR has triggered much effort for designing targeted therapy. These approaches include TK inhibition, monoclonal antibody, vaccine, and RNA-based downregulation of the receptor. Treatment success requires that the drug penetrates the blood-brain barrier and has low systemic toxicity but high selectivity for the tumor. While the blockade of EGFR-dependent processes resulted in experimental and clinical treatment success, cells capable of using alternative signaling ultimately escape this strategy. A combination of interventions targeting tumor-specific cell surface regulators along with convergent downstream signaling pathways will likely enhance efficacy. Studies on EGFR in glioblastoma have revealed much information about the complexity of gliomagenesis and also facilitated the development of strategies for targeting drivers of tumor growth and combination therapies with increasing complexity.

Role of sorafenib in the treatment of advanced hepatocellular carcinoma: An update

Sorafenib is the first and only p.o. administrated drug currently approved to treat advanced hepatocellular carcinoma (HCC). However, concerns have been raised about sorafenib therapy, including acquired drug resistance. This review provides an overview of sorafenib in the treatment of HCC on the basis of data obtained in the laboratory and in clinical studies. Three underlying mechanisms have been found to support sorafenib therapy. First, sorafenib blocks HCC cell proliferation by inhibiting BRaf and Raf1/c-Raf serine/threonine kinase phosphorylation in the mitogen-activated protein kinase pathway. Second, sorafenib induces apoptosis by reducing elF4E phosphorylation and downregulating Mcl-1 levels in tumor cells. Third, sorafenib prevents tumor-associated angiogenesis by inactivating vascular endothelial growth factor receptors (VEGFR-2 and -3) and the platelet-derived growth factor receptor-β. Clinical trials have demonstrated the effectiveness and relative safety of sorafenib, and thus the drug is used in unresectable HCC. However, many patients may develop acquired resistance to sorafenib, so their response to sorafenib is eventually lost. Sorafenib may induce autophagy, which leads to apoptosis. However, autophagy can also cause drug resistance. Many studies have combined sorafenib with other treatments in an effort to increase its effects, reduce the necessary dose or overcome resistance. It is urgent to study the mechanisms underlying how sorafenib interacts with cellular molecules and other drugs to increase its efficacy and reduce resistance in HCC patients.

Role of sorafenib in the treatment of advanced hepatocellular carcinoma: An update

Sorafenib is the first and only p.o. administrated drug currently approved to treat advanced hepatocellular carcinoma (HCC). However, concerns have been raised about sorafenib therapy, including acquired drug resistance. This review provides an overview of sorafenib in the treatment of HCC on the basis of data obtained in the laboratory and in clinical studies. Three underlying mechanisms have been found to support sorafenib therapy. First, sorafenib blocks HCC cell proliferation by inhibiting BRaf and Raf1/c-Raf serine/threonine kinase phosphorylation in the mitogen-activated protein kinase pathway. Second, sorafenib induces apoptosis by reducing elF4E phosphorylation and downregulating Mcl-1 levels in tumor cells. Third, sorafenib prevents tumor-associated angiogenesis by inactivating vascular endothelial growth factor receptors (VEGFR-2 and -3) and the platelet-derived growth factor receptor-β. Clinical trials have demonstrated the effectiveness and relative safety of sorafenib, and thus the drug is used in unresectable HCC. However, many patients may develop acquired resistance to sorafenib, so their response to sorafenib is eventually lost. Sorafenib may induce autophagy, which leads to apoptosis. However, autophagy can also cause drug resistance. Many studies have combined sorafenib with other treatments in an effort to increase its effects, reduce the necessary dose or overcome resistance. It is urgent to study the mechanisms underlying how sorafenib interacts with cellular molecules and other drugs to increase its efficacy and reduce resistance in HCC patients.