Selective ablation of Notch3 in HCC enhances doxorubicin's death promoting effect by a p53 dependent mechanism

Heterogeneity of hepatocellular carcinoma that responds differently to combination therapy with TACE and Sorafenib as determined by digital spatial gene expression profiling

BACKGROUND

The combination of Sorafenib and transcatheter arterial chemoembolization (TACE) exhibits limited efficacy in the treatment of certain advanced hepatocellular carcinomas (HCC), and the molecular mechanisms underlying resistance to this combination remain unclear.

OBJECTIVE

This study aims to underscore the distinctive contribution of GeoMx DSP technology in elucidating the molecular intricacies of HCC resistance to the Sorafenib and TACE combination.

METHODS

Patients with advanced HCC during the waiting period before liver transplantation were classified into sensitive and resistant groups based on their response to Sorafenib and TACE combination therapy. Employing GeoMx DSP technology for comprehensive gene expression profiling, we identified pivotal molecular targets linked to resistance against combination therapy.

RESULTS

The investigation scrutinized intra-tumoral and inter-individual variances, unveiling a spectrum of crucial molecular targets, such as PLG, PLVAP, immunoglobulin genes, ORM1, and NR4A1, among others. Additionally, we explored signaling pathways associated with treatment responsiveness, including the PPAR signaling pathway. Notably, we emphasized the significance of the immune microenvironment characterized by heightened SPP1 expression in HCC resistance to combination therapy. In the resistant group, SPP1+ tumor-associated macrophage (TAM) infiltration was notably pronounced (p = 0.037), while T-cell depletion showed a mitigated presence (p = 0.013).

CONCLUSION

The study reveals intra- and inter-individual heterogeneity in HCC that is differentially responsive to the combination of Sorafenib and TACE, highlighting multiple key molecular targets associated with treatment resistance. The immune microenvironment is important, and in particular, SPP1+ TAM infiltration may play a key role. Meanwhile, the introduction of immunotherapy in patients resistant to combination therapy may lead to positive results.

Extracellular vesicles and cancer stem cells: a deadly duo in tumor progression

The global incidence of cancer is increasing, with estimates suggesting that there will be 26 million new cases and 17 million deaths per year by 2030. Cancer stem cells (CSCs) and extracellular vesicles (EVs) are key to the resistance and advancement of cancer. They play a crucial role in tumor dynamics and resistance to therapy. CSCs, initially discovered in acute myeloid leukemia, are well-known for their involvement in tumor initiation, progression, and relapse, mostly because of their distinct characteristics, such as resistance to drugs and the ability to self-renew. EVs, which include exosomes, microvesicles, and apoptotic bodies, play a vital role in facilitating communication between cells within the tumor microenvironment (TME). They have a significant impact on cellular behaviors and contribute to genetic and epigenetic changes. This paper analyzes the mutually beneficial association between CSCs and EVs, emphasizing their role in promoting tumor spread and developing resistance mechanisms. This review aims to investigate the interaction between these entities in order to discover new approaches for attacking the complex machinery of cancer cells. It highlights the significance of CSCs and EVs as crucial targets in the advancement of novel cancer treatments, which helps stimulate additional research, promote progress in ideas for cancer treatment, and provide renewed optimism in the effort to reduce the burden of cancer.

Emerging trends in gastrointestinal cancers: Targeting developmental pathways in carcinogenesis and tumor progression

Gastrointestinal carcinomas are a group of cancers associated with the digestive system and its accessory organs. The most prevalent cancers related to the gastrointestinal tract are colorectal, gall bladder, gastric, hepatocellular, and esophageal cancers, respectively. Molecular aberrations in different signaling pathways, such as signal transduction systems or developmental pathways are the chief triggering mechanisms in different cancers Though a massive advancement in diagnostic and therapeutic interventions results in improved survival of patients with gastrointestinal cancer; the lower malignancy stages of these carcinomas are comparatively asymptomatic. Various gastrointestinal-related cancers are detected at advanced stages, leading to deplorable prognoses and increased rates of recurrence. Recent molecular studies have elucidated the imperative roles of several signaling pathways, namely Wnt, Hedgehog, and Notch signaling pathways, play in the progression, therapeutic responsiveness, and metastasis of gastrointestinal-related cancers. This book chapter gives an interesting update on recent findings on the involvement of developmental signaling pathways their mechanistic insight in gastrointestinalcancer. Subsequently, evidences supporting the exploration of gastrointestinal cancer related molecular mechanisms have also been discussed for developing novel therapeutic strategies against these debilitating carcinomas.

Current therapeutic modalities and chemopreventive role of natural products in liver cancer: Progress and promise

Liver cancer is a severe concern for public health officials since the clinical cases are increasing each year, with an estimated 5-year survival rate of 30%–35% after diagnosis. Hepatocellular carcinoma (HCC) constitutes a significant subtype of liver cancer (approximate75%) and is considered primary liver cancer. Treatment for liver cancer mainly depends on the stage of its progression, where surgery including, hepatectomy and liver transplantation, and ablation and radiotherapy are the prime choice. For advanced liver cancer, various drugs and immunotherapy are used as first-line treatment, whereas second-line treatment includes chemotherapeutic drugs from natural and synthetic origins. Sorafenib and lenvatinib are first-line therapies, while regorafenib and ramucirumab are second-line therapy. Various metabolic and signaling pathways such as Notch, JAK/ STAT, Hippo, TGF-β, and Wnt have played a critical role during HCC progression. Dysbiosis has also been implicated in liver cancer. Drug-induced toxicity is a key obstacle in the treatment of liver cancer, necessitating the development of effective and safe medications, with natural compounds such as resveratrol, curcumin, diallyl sulfide, and others emerging as promising anticancer agents. This review highlights the current status of liver cancer research, signaling pathways, therapeutic targets, current treatment strategies and the chemopreventive role of various natural products in managing liver cancer.

Immunotherapy and the Combination with Targeted Therapies for Advanced Hepatocellular Carcinoma

One of the most important abilities of a tumor is to establish a state of immunosuppression inside the tumor microenvironment. This is made possible through numerous mechanisms of tumor immune escape that have been identified in experimental studies during the last decades. In addition, the hepatic microenvironment is commonly oriented towards a state of immune tolerance because the liver receives blood from the hepatic arteries and portal veins containing a variety of endogenous antigens. Therefore, the hepatic microenvironment establishes an autoimmune tolerance, preventing an autoimmune reaction in the liver. On this basis, hepatic tumor cells may escape the immune system, avoiding being recognized and destroyed by immune cells. Moreover, since the etiology of Hepatocellular Carcinoma (HCC) is often related to cirrhosis, and hepatitis B or C, this tumor develops in the context of chronic inflammation. Thus, the HCC microenvironment is characterized by important immune cell infiltration. Given these data and the poor prognosis of advanced HCC, different immunotherapeutic strategies have been developed and evaluated for these patients. In this review, we describe all the clinical applications of immunotherapy for advanced HCC, from the drugs that have already been approved to the ongoing clinical trials.

Targeting Notch to Maximize Chemotherapeutic Benefits: Rationale, Advanced Strategies, and Future Perspectives

Simple Summary

The Notch signaling pathway regulates cell proliferation, apoptosis, stem cell self-renewal, and differentiation in a context-dependent fashion both during embryonic development and in adult tissue homeostasis. Consistent with its pleiotropic physiological role, unproper activation of the signaling promotes or counteracts tumor pathogenesis and therapy response in distinct tissues. In the last twenty years, a wide number of studies have highlighted the anti-cancer potential of Notch-modulating agents as single treatment and in combination with the existent therapies. However, most of these strategies have failed in the clinical exploration due to dose-limiting toxicity and low efficacy, encouraging the development of novel agents and the design of more appropriate combinations between Notch signaling inhibitors and chemotherapeutic drugs with improved safety and effectiveness for distinct types of cancer.

Abstract

Notch signaling guides cell fate decisions by affecting proliferation, apoptosis, stem cell self-renewal, and differentiation depending on cell and tissue context. Given its multifaceted function during tissue development, both overactivation and loss of Notch signaling have been linked to tumorigenesis in ways that are either oncogenic or oncosuppressive, but always context-dependent. Notch signaling is critical for several mechanisms of chemoresistance including cancer stem cell maintenance, epithelial-mesenchymal transition, tumor-stroma interaction, and malignant neovascularization that makes its targeting an appealing strategy against tumor growth and recurrence. During the last decades, numerous Notch-interfering agents have been developed, and the abundant preclinical evidence has been transformed in orphan drug approval for few rare diseases. However, the majority of Notch-dependent malignancies remain untargeted, even if the application of Notch inhibitors alone or in combination with common chemotherapeutic drugs is being evaluated in clinical trials. The modest clinical success of current Notch-targeting strategies is mostly due to their limited efficacy and severe on-target toxicity in Notch-controlled healthy tissues. Here, we review the available preclinical and clinical evidence on combinatorial treatment between different Notch signaling inhibitors and existent chemotherapeutic drugs, providing a comprehensive picture of molecular mechanisms explaining the potential or lacking success of these combinations.

Hepatic Cancer Stem Cells: Molecular Mechanisms, Therapeutic Implications, and Circulating Biomarkers

Hepatocellular carcinoma (HCC) is one of the deadliest cancers. HCC is associated with multiple risk factors and is characterized by a marked tumor heterogeneity that makes its molecular classification difficult to apply in the clinics. The lack of circulating biomarkers for the diagnosis, prognosis, and prediction of response to treatments further undermines the possibility of developing personalized therapies. Accumulating evidence affirms the involvement of cancer stem cells (CSCs) in tumor heterogeneity, recurrence, and drug resistance. Owing to the contribution of CSCs to treatment failure, there is an urgent need to develop novel therapeutic strategies targeting, not only the tumor bulk, but also the CSC subpopulation. Clarification of the molecular mechanisms influencing CSC properties, and the identification of their functional roles in tumor progression, may facilitate the discovery of novel CSC-based therapeutic targets to be used alone, or in combination with current anticancer agents, for the treatment of HCC. Here, we review the driving forces behind the regulation of liver CSCs and their therapeutic implications. Additionally, we provide data on their possible exploitation as prognostic and predictive biomarkers in patients with HCC.

The Role of Notch3 Signaling in Cancer Stemness and Chemoresistance: Molecular Mechanisms and Targeting Strategies

Aberrant Notch signaling profoundly affects cancer progression. Especially the Notch3 receptor was found to be dysregulated in cancer, where its expression is correlated with worse clinicopathological features and poor prognosis. The activation of Notch3 signaling is closely related to the activation of cancer stem cells (CSCs), a small subpopulation in cancer that is responsible for cancer progression. In addition, Notch3 signaling also contributes to tumor chemoresistance against several drugs, including doxorubicin, platinum, taxane, epidermal growth factor receptor (EGFR)–tyrosine kinase inhibitors (TKIs) and gemcitabine, through complex mechanisms. In this review, we mainly focus on discussing the molecular mechanisms by which Notch3 modulates cancer stemness and chemoresistance, as well as other cancer behaviors including metastasis and angiogenesis. What’s more, we propose potential treatment strategies to block Notch3 signaling, such as non-coding RNAs, antibodies and antibody-drug conjugates, providing a comprehensive reference for research on precise targeted cancer therapy.

Tspan5 promotes epithelial-mesenchymal transition and tumour metastasis of hepatocellular carcinoma by activating Notch signalling

Hepatocellular carcinoma (HCC) is one of the most lethal cancers worldwide due to a high rate of tumour metastasis and disease recurrence. In physiological conditions, tetraspanins interact with specific partner proteins in tetraspanin-enriched microdomains and regulate their subcellular localization and function. However, the function of Tspan5 in pathological processes, particularly in cancer biology and its clinical significance, are still unclear. Here, we describe that a high expression of Tspan5 is significantly associated with some clinicopathological features including invasive length, vascular invasion, clinical stage and poor overall survival of HCC patients. Alterations of Tspan5 expression by lentivirus transductions in HCC cells demonstrated that Tspan5 promotes wound healing and cell migration in vitro and tumour metastasis of HCC cells in vivo. Mechanistic studies revealed that Tspan5 promoted cell migration and tumour metastasis by increasing the enzymatic maturation of ADAM10 and activating Notch signalling via the increase of the cleavage of the Notch1 receptor catalysed by the γ-secretase complex. Activation of Notch signalling by Tspan5 was shown further to enhance the epithelial-mesenchymal transition (EMT) and actin skeleton rearrangement of tumour cells. In clinical HCC samples, Tspan5 expression is strongly correlated with many key molecules acting in Notch signalling and EMT, highlighting the role of Tspan5 in the regulation of Notch signalling, EMT and tumour metastasis of HCC. Our findings provide new insights into the mechanism of tumour metastasis and disease progression of HCC and may facilitate the development of novel clinical intervention strategies against HCC.

Synthesis of sophocarpine triflorohydrazone and its proliferation inhibition and apoptosis induction activity in myeloma cells through Notch3-p53 signaling activation

Multiple myeloma is indicated by the presence of excessive monoclonal plasma cells in bone marrow, which result in the formation of osteolytic lesions. The present study investigated SCA as anti-proliferative agent for myeloma cells and explored the mechanism associated. Effect of SCA on viabilities of KRASA12 and AMO-1 cells was evaluated by MTT assay and apoptotic ratio using flow cytometry. Protein expression was investigated by western blotting and expression of genes related to Notch3-p53 signaling axis using RT-PCR assay. Increase in SCA concentration caused a significant (P < .01) reduction in KRASA12 and AMO-1 cell viability. The KRASA12 and AMO-1 cell viabilities were reduced to 29% and 21%, respectively on treatment with 21 μM doses of SCA. SCA treatment of KRASA12 and AMO-1 cells significantly (P < .05) increased apoptosis compared with untreated cells. The Bcl-2 (26 kDa) protein expression was reduced whereas the Bax (21 kDa) and cleaved caspase-3 levels elevated in SCA treated KRASA12 and AMO-1 cells. Treatment with SCA significantly promoted Hes1, p53 (53 kDa) and Hey1 mRNA expression in KRASA12 and AMO-1 cells. Treatment of KRASA12 and AMO-1 cells with SCA led to a marked reduction in Notch3 protein expression. SCA inhibits KRASA12 and AMO-1 myeloma cell proliferation by promoting pro-apoptotic proteins. Moreover, SCA treatment suppressed Hes1 and Hey1 mRNA expression and targeted Notch3 expression. Therefore, SCA may be studied further for development of treatment for myeloma.

Notch Signaling Regulation in HCC: From Hepatitis Virus to Non-Coding RNAs

The Notch family includes evolutionary conserved genes that encode for single-pass transmembrane receptors involved in stem cell maintenance, development and cell fate determination of many cell lineages. Upon activation by different ligands, and depending on the cell type, Notch signaling plays pleomorphic roles in hepatocellular carcinoma (HCC) affecting neoplastic growth, invasion capability and stem like properties. A specific knowledge of the deregulated expression of each Notch receptor and ligand, coupled with resultant phenotypic changes, is still lacking in HCC. Therefore, while interfering with Notch signaling might represent a promising therapeutic approach, the complexity of Notch/ligands interactions and the variable consequences of their modulations raises concerns when performed in undefined molecular background. The gamma-secretase inhibitors (GSIs), representing the most utilized approach for Notch inhibition in clinical trials, are characterized by important adverse effects due to the non-specific nature of GSIs themselves and to the lack of molecular criteria guiding patient selection. In this review, we briefly summarize the mechanisms involved in Notch pathway activation in HCC supporting the development of alternatives to the γ-secretase pan-inhibitor for HCC therapy.

Molecular mechanisms of astragaloside‑IV in cancer therapy (Review)

Radix Astragali (RA) is widely used in traditional Chinese medicine (TCM), and astragaloside IV (AS-IV) is the most critical component of RA. Previous studies have demonstrated that AS-IV exerts effects on the myocardium, nervous system and endocrine system, among others. In the present review article, data from studies conducted over the past 20 years were collated, which have evaluated the effects of AS-IV on tumors. The mechanisms of action of AS-IV on malignant cells both in vivo and in vitro were summarized and it was demonstrated that AS-IV plays a vital role, particularly in inhibiting tumor growth and metastasis, promoting the apoptosis of tumor cells, enhancing immune function and preventing drug resistance. Moreover, AS-IV controls several epithelial-mesenchymal transformation (EMT)-related and autophagy-related pathways, such as the phosphoinositide-3-kinase (PI3K)/protein kinase B (AKT), Wnt/β-catenin, mitogen-activated protein kinase (MAPK)/extracellular regulated protein kinase (ERK) and transforming growth factor-β (TGF-β)/SMAD signaling pathways, which are commonly affected in the majority of tumors. The present review provides new perspectives on the functions of AS-IV and its role as an adjuvant treatment in cancer chemotherapy.

Novel molecular targets in hepatocellular carcinoma

Globally, hepatocellular carcinoma (HCC) is a leading cause of cancer and cancer-related deaths. The therapeutic efficacy of locoregional and systemic treatment in patients with advanced HCC remains low, which results in a poor prognosis. The development of sorafenib for the treatment of HCC has resulted in a new era of molecular targeted therapy for this disease. However, the median overall survival was reported to be barely higher in the sorafenib treatment group than in the control group. Hence, in this review we describe the importance of developing more effective targeted therapies for the management of advanced HCC. Recent investigations of molecular signaling pathways in several cancers have provided some insights into developing molecular therapies that target critical members of these signaling pathways. Proteins involved in the Hedgehog and Notch signaling pathways, Polo-like kinase 1, arginine, histone deacetylases and Glypican-3 can be potential targets in the treatment of HCC. Monotherapy has limited therapeutic efficacy due to the development of inhibitory feedback mechanisms and induction of chemoresistance. Thus, emphasis is now on the development of personalized and combination molecular targeted therapies that can serve as ideal therapeutic strategies for improved management of HCC.

Mechanisms of cancer stem cell therapy

Cancer stem cells (CSCs) are responsible for carcinogenesis and tumorigenesis and are involved in drug and radiation resistance, metastasis, tumor relapse and initiation. Remarkably, they have other abilities such as inheritance of self-renewal and de-differentiation. Hence, targeting CSCs is considered a potential anti-cancer therapeutic strategy. Recent advances in the identification of biomarkers to recognize CSCs and the development of new techniques to evaluate tumorigenic and carcinogenic roles of CSCs are instrumental to this approach. Elucidation of signaling pathways that regulate CSCs colony progression and drug resistance are critical in establishing effective targeted therapies. CSCs play a central key role in immunomodulation, immune evasion and effector immunity, which alters immune system balancing. These include mTOR, SHH, NOTCH and Wnt/β-catering in cancer progression. In this review article, we discuss the importance of these CSCs pathways in cancer therapy.

Genetic polymorphisms and transcription profiles associated with intracranial aneurysm: a key role for NOTCH3

Intracranial aneurysm (IA) incidence is about 1~2%. However, the specific mechanisms of IA onset and development need further study. Our objective was to discover novel IA-related genes to determine possible etiologies further. We performed next-generation sequencing on nineteen Chinese patients with familial IA and one patient with sporadic IA. We obtained mRNA expression data of 129 samples from Gene Expression Omnibus (GEO) and made statistical computing to discover differentially expressed genes (DEGs). The screened IA-related gene NOTCH3 was determined by bioinformatic data mining. We verified the IA-related indicators of NOTCH3. Association was found between IA and the NOTCH3 SNPs rs779314594, rs200504060 and rs2285981. Levels of NOTCH3 mRNA were lower in IA tissue than in control tissue, but higher in peripheral blood neutrophils from IA patients than in neutrophils from controls. Levels of NOTCH3 protein were lower in IA tissue than in cerebral artery tissue. NOTCH3 also decreased the expression of angiogenesis factors in human umbilical vein endothelial cells. Variation in NOTCH3 and alteration of its expression in cerebral artery or neutrophils may contribute to IA. Our findings also describe a bioinformatic-experimental approach that may prove useful for probing the pathophysiology of other complex diseases.

Top Notch Targeting Strategies in Cancer: A Detailed Overview of Recent Insights and Current Perspectives

Evolutionarily conserved Notch plays a critical role in embryonic development and cellular self-renewal. It has both tumour suppressor and oncogenic activity, the latter of which is widely described. Notch-activating mutations are associated with haematological malignancies and several solid tumours including breast, lung and adenoid cystic carcinoma. Moreover, upregulation of Notch receptors and ligands and aberrant Notch signalling is frequently observed in cancer. It is involved in cancer hallmarks including proliferation, survival, migration, angiogenesis, cancer stem cell renewal, metastasis and drug resistance. It is a key component of cell-to-cell interactions between cancer cells and cells of the tumour microenvironment, such as endothelial cells, immune cells and fibroblasts. Notch displays diverse crosstalk with many other oncogenic signalling pathways, and may drive acquired resistance to targeted therapies as well as resistance to standard chemo/radiation therapy. The past 10 years have seen the emergence of different classes of drugs therapeutically targeting Notch including receptor/ligand antibodies, gamma secretase inhibitors (GSI) and most recently, the development of Notch transcription complex inhibitors. It is an exciting time for Notch research with over 70 cancer clinical trials registered and the first-ever Phase III trial of a Notch GSI, nirogacestat, currently at the recruitment stage.

NOTCH3 T6746C and TP53 P72R Polymorphisms Are Associated with the Susceptibility to Diffuse Cutaneous Systemic Sclerosis

Introduction. NOTCH pathway and TP53 protein are involved in the development of fibrosis and autoimmune disorders, respectively. The aim of this study was to evaluate the role of single nucleotide polymorphisms (SNPs) of NOTCH3 and TP53 genes and serum anti-TP53 antibodies with the susceptibility, clinical subset of systemic sclerosis (SSc), and clinical profile of SSc patient, particularly with lung involvement and disease activity. Objects and Methods. 124 white Polish SSc patients (101 with limited cutaneous SSc-lcSSc, and 23 with diffuse cutaneous SSc-dcSSc) and 100 healthy individuals were included in the study. Patients were assessed for the presence of autoantibodies and interstitial lung disease. Two SNPs at position 6746 of NOTCH3 and TP53 genes and serum anti-TP53 antibodies with the susceptibility, clinical subset of systemic sclerosis (SSc), and clinical profile of SSc patient, particularly with lung involvement and disease activity.

Results

The genotypic frequencies of the NOTCH3 and p=0.03; χ ² = 4.63). There was no significant difference between SSc patients and the control population in allele frequencies of both SNPs. The CT + CC genotypes of NOTCH3 and p=0.03; p=0.03; p=0.03; TP53 genes and serum anti-TP53 antibodies with the susceptibility, clinical subset of systemic sclerosis (SSc), and clinical profile of SSc patient, particularly with lung involvement and disease activity. p=0.03.

Conclusion

The CT + CC genotypes of NOTCH3 gene and PR + RR genotypes of the TP53 gene increased the risk of dcSSc development. Moreover, genotypes of CT + CC were associated with the active form of SSc suggesting the role of the NOTCH pathway in the pathogenesis of this disease.NOTCH3 and TP53 genes and serum anti-TP53 antibodies with the susceptibility, clinical subset of systemic sclerosis (SSc), and clinical profile of SSc patient, particularly with lung involvement and disease activity.

Physcion Synergistically Enhances the Cytotoxicity of Sorafenib in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is a common human malignancy. Physcion is a naturally occurring anthraquinone derivative found in plant and marine sources. Our previous studies have indicated that physcion could suppress tumor growth and induce apoptosis in HCC. This study was aimed to investigate the effect of a combination of physcion and sorafenib on HCC. Our findings indicated that physcion could significantly augment the antiproliferative and proapoptotic activities of sorafenib in vitro and in vivo. Mechanistically, the synergistic effect correlates with physcion-induced suppression of Notch3/AKT signaling. This preclinical evidence highlights the potential application of physcion in the treatment of HCC. Anat Rec, 302:2171-2177, 2019. © 2019 American Association for Anatomy.

The Carcinogenic Role of the Notch Signaling Pathway in the Development of Hepatocellular Carcinoma

The Notch signaling pathway, known to be a highly conserved signaling pathway in embryonic development and adult tissue homeostasis, participates in cell fate decisions that include cellular differentiation, cell survival and cell death. However, other studies have shown that aberrant in Notch signaling is pro-tumorigenic, particularly in hepatocellular carcinoma (HCC). HCC is one of the most common malignant tumors in the world and has a high mortality rate. Growing evidence supports that Notch signaling plays a critical role in the development of HCC by regulating the tumor microenvironment, tumorigenesis, progression, angiogenesis, invasion and metastasis. Accordingly, overexpression of Notch is closely associated with poor prognosis in HCC. In this review, we focus on the pro-tumorigenic role of Notch signaling in HCC, summarize the current knowledge of Notch signaling and its role in HCC development, and outline the therapeutic potential of targeting Notch signaling in HCC.

Brivanib in combination with Notch3 silencing shows potent activity in tumour models

BACKGROUND

Sorafenib is the first targeted agent proven to improve survival of patients with advanced hepatocellular carcinoma (HCC) and it has been used in first line treatments with heterogeneous response across patients. Most of the promising agents evaluated in first-line or second-line phase III trials for HCC failed to improve patient survival. The absence of molecular characterisation, including the identification of pathways driving resistance might be responsible for these disappointing results.

METHODS

2D DIGE and MS analyses were used to reveal proteomic signatures resulting from Notch3 inhibition in HepG2 cells, combined with brivanib treatment. The therapeutic potential of Notch3 inhibition combined with brivanib treatment was also demonstrated in a rat model of HCC and in cell lines derived from different human cancers.

RESULTS

Using a proteomic approach, we have shown that Notch3 is strongly involved in brivanib resistance through a p53-dependent regulation of enzymes of the tricarboxylic acid (TCA), both in vitro and in vivo.

CONCLUSION

We have demonstrated that regulation of the TCA cycle is a common mechanism in different human cancers, suggesting that Notch3 inhibitors combined with brivanib treatment may represent a strong formulation for the treatment of HCC as well as Notch3-driven cancers.

Apoptosis of mouse myeloma cells induced by curcumin via the Notch3-p53 signaling axis

Resistance to apoptosis is a characteristic of cancer. Curcumin has become a potential anticancer drug for its pro-apoptotic effects, but the underlying mechanisms remain unclear. Furthermore, the Notch3-p53 signaling axis serves an important role in cell fate. The present study was designed to investigate the antitumor effect of curcumin by the Notch3-p53 axis in mouse myeloma P3X63Ag8 cells. The effects of curcumin on the viability of P3X63Ag8 cells were evaluated using an MTT assay. Quantitative expression of the Notch3-p53 signaling axis-associated genes was measured by reverse transcription-quantitative polymerase chain reaction, and western blot analysis was used to investigate the expression of proteins. Additionally, flow cytometry was used to measure the ratio of apoptosis. The results demonstrated that curcumin could significantly inhibit cell viability. No significant pro-apoptotic effect was observed when the concentration of curcumin was <30 µM. At 30 µM, curcumin-treated cells exhibited an apoptotic phenomenon, and the ratio of late apoptosis increased with the concentration of curcumin, and reached 28.4 and 51.8% in the medium- and high-dose groups, respectively. Curcumin inhibited the expression of Notch3, while the middle- and high-dose groups promoted p53. The expression of Notch3-responsive genes Hes family BHLH transcription factor 1 and Hes-related family transcription factor with YRPW motif 1 were notably promoted. Curcumin treatment significantly downregulated B-cell lymphoma-2 (Bcl-2) at the mRNA and protein levels, but upregulated Bcl-2-associated X. These data indicated that curcumin exhibited antitumor effects in mouse myeloma cells with induction of apoptosis by affecting the Notch3-p53 signaling axis.

Evaluation of the role of Notch1 expression in hepatic carcinogenesis with clinico-pathological correlation

The role of Notch pathway in hepatocarcinogenesis is unclear with conflicting results reported from different researchers. This study aimed to investigate the exact role of Notch1 in hepatocarcinogenesis and its influence on survival and to determine the possibility of it being a target therapy. Differential immunohistochemical expression of Notch1 in 100 cases of hepatocellular carcinoma (HCC) and adjacent non-neoplastic liver tissue was performed. The results showed that expression of Notch1 was significantly higher in the non-neoplastic hepatic tissues than in HCC tissues (p < 0.001), but there was no significant difference in Notch1 expression between cirrhotic and non-cirrhotic liver tissue (p = 0.197). Notch1 expression was higher in low grade than in high grade HCC (p = 0.036). Notch1 expression showed reverse correlation with mitotic count (p = 0.008), and necrosis (p = 0.005). The disease free survival was shorter in patients displaying low levels of Notch1 expression (p = 0.045). The overall survival showed no significant difference between high and low levels of Notch1 expression; however, it was somewhat longer in patients with high Notch1 expression (p = 0.220). In conclusion, the tumour suppressor role of Notch1 was supported and the use of Notch1 agonists may have a role in improving the prognosis of HCC.

The Role of Notch3 in Cancer

The Notch family is a highly conserved gene group that regulates cell-cell interaction, embryogenesis, and tissue commitment. This review article focuses on the third Notch family subtype, Notch3. Regulation via Notch3 signaling was first implicated in vasculogenesis. However, more recent findings suggest that Notch3 signaling may play an important role in oncogenesis, tumor maintenance, and resistance to chemotherapy. Its role is mainly oncogenic, although in some cancers it appears to be tumor suppressive. Despite the wealth of published literature, it remains relatively underexplored and requires further research to shed more light on its role in cancer development, determine its tissue-specific function, and elaborate novel treatment strategies. Herein we summarize the role of Notch3 in cancer, possible mechanisms of its action, and current cancer treatment strategies targeting Notch3 signaling.

IMPLICATIONS FOR PRACTICE

The Notch family is a highly conserved gene group that regulates cell-cell interaction, embryogenesis, and tissue commitment. This review summarizes the existing data on the third subtype of the Notch family, Notch3. The role of Notch3 in different types of cancers is discussed, as well as implications of its modification and new strategies to affect Notch3 signaling activity.

Molecular bases of the poor response of liver cancer to chemotherapy

A characteristic shared by most frequent types of primary liver cancer, i.e., hepatocellular carcinoma (HCC) and cholangiocarcinoma (CCA) in adults, and in a lesser extent hepatoblastoma (HB) mainly in children, is their high refractoriness to chemotherapy. This is the result of synergic interactions among complex and diverse mechanisms of chemoresistance (MOC) in which more than 100 genes are involved. Pharmacological treatment, although it can be initially effective, frequently stimulates the expression of MOC genes, which results in the relapse of the tumor, usually with a more aggressive and less chemosensitive phenotype. Identification of the MOC genetic signature accounting for the "resistome" present at each moment of tumor life would prevent the administration of chemotherapeutic regimens without chance of success but still with noxious side effects for the patient. Moreover, a better description of cancer cells strength is required to develop novel strategies based on pharmacological, cellular or gene therapy to overcome liver cancer chemoresistance.

MDM2-p53 Interactions in Human Hepatocellular Carcinoma: What Is the Role of Nutlins and New Therapeutic Options?

Human hepatocellular carcinoma (HCC) is the fifth most common cancer and is associated with poor prognosis worldwide. The molecular mechanisms underlying the pathogenesis of HCC have been an area of continuing interest, and recent studies using next generation sequencing (NGS) have revealed much regarding previously unsettled issues. Molecular studies using HCC samples have been mainly targeted with the aim to identify the fundamental mechanisms contributing to HCC and identify more effective treatments. In response to cellular stresses (e.g., DNA damage or oncogenes), activated p53 elicits appropriate responses that aim at DNA repair, genetic stability, cell cycle arrest, and the deletion of DNA-damaged cells. On the other hand, the murine double minute 2 (MDM2) oncogene protein is an important cellular antagonist of p53. MDM2 negatively regulates p53 activity through the induction of p53 protein degradation. However, current research has shown that the mechanisms underlying MDM2-p53 interactions are more complex than previously thought. Microarray data have added new insight into the transcription changes in HCC. Recently, Nutlin-3 has shown potency against p53-MDM2 binding and the enhancement of p53 stabilization as well as an increment of p53 cellular accumulation with potential therapeutic effects. This review outlines the molecular mechanisms involved in the p53-MDM2 pathways, the biological factors influencing these pathways, and their roles in the pathogenesis of HCC. It also discusses the action of Nutlin-3 treatment in inducing growth arrest in HCC and elaborates on future directions in research in this area. More research on the biology of p53-MDM2 interactions may offer a better understanding of these mechanisms and discover new biomarkers, sensitive prognostic indicators as well as new therapeutic interventions in HCC.

Notch3 overexpression enhances progression and chemoresistance of urothelial carcinoma

Abnormal activation of Notch signaling is involved in the etiology of various diseases, including cancer, but the association between Notch3 expression in urothelial cancer and clinical outcome remains unclear, and the molecular mechanisms underlying Notch3 signaling activation are not well defined. In this study we examined 59 urothelial cancer patients and found that Notch3 was more highly expressed in human urothelial cancer tissues than in non-tumorous bladder tissue samples, with Notch3 overexpression being associated with poor clinical outcome. Notch3 knockdown resulted in decreased proliferation of urothelial cancer cells in vitro and decreased xenograft tumor growth in vivo. In addition, Notch3 knockdown rendered urothelial cancer cells more sensitive to cisplatin. Furthermore, suberoylanilide hydroxamic acid (SAHA, a histone deacetylase [HDAC] inhibitor) induced acetylation of NOTCH3, downregulated Notch 3, prevented urothelial cancer cell proliferation, and induced cell cycle arrest. Taken together, these data suggested that Notch 3 overexpression promotes growth and chemoresistance in urothelial cancer.

Resistance a major hindrance to chemotherapy in hepatocellular carcinoma: an insight

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer mortality, accounting for almost 90% of total liver cancer burden. Surgical resection followed by adjuvant and systemic chemotherapy are the most meticulously followed treatment procedures but the complex etiology and high metastatic potential of the disease renders surgical treatment futile in majority of the cases. Another hindrance to the scenario is the acquired resistance to drugs resulting in relapse of the disease. Hence, to provide insights into development of novel therapeutic targets and diagnostic biomarkers, this review focuses on the various molecular mechanisms underlying chemoresistance in HCC. We have provided a comprehensive summary of the various strategies adopted by HCC cells, extending from apoptosis evasion, autophagy activation, drug expulsion to epigenetic transformation as modes of therapy resistance. The role of stem cells in imparting chemoresistance is also discussed. Furthermore, the review also focuses on how this knowledge might be exploited for the development of an effective, prospective therapy against HCC.

MiR-199-3p replacement affects E-cadherin expression through Notch1 targeting in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) represents the second cause of cancer-related mortality worldwide and is associated with poor prognosis, due to a high recurrence rate after curative treatments and a drug resistance phenotype. In this scenario, the identification of innovative and effective therapeutic strategies is an unmet clinical need. The safety and efficacy of microRNA (miRNA) mediated approaches in preclinical models and clinical trials have been widely described in cancer. MicroRNA-199a downregulation is a common feature of HCC where its reduced expression contributes to mTOR and c-Met pathways activation. Notch1 activation is also a common event in HCC, influencing epithelial-to-mesenchymal transition, tumor invasion and recurrence at least in part through E-cadherin regulation. Here we identified a negative correlation between miR-199a-3p and Notch1 or E-cadherin protein levels in HCC patients and demonstrated that miR-199a-3p regulates E-cadherin expression through Notch1 direct targeting in in vitro models. Moreover, we showed that a strong correlation exists between miR-199a-5p and miR-199a-3p in HCC specimens and that miR-199a-5p contributes to E-cadherin regulation as well, underlying the complex network of interaction carried out by miR-199a and its influence on tumor aggressiveness. In conclusion, our findings suggest the restoration of miR-199a-3p physiologic levels as a possible therapeutic strategy for the treatment of HCC.

Molecular and proteomic insight into Notch1 characterization in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) ranks fifth in frequency worldwide amongst all human cancers causing one million deaths annually. Despite many promising treatment options, long-term prognosis remains dismal for the majority of patients who develop recurrence or present with advanced disease. Notch signaling is an evolutionarily conserved pathway crucial for the development and homeostasis of many organs including liver. Herein we showed that aberrant Notch1 is linked to HCC development, tumor recurrence and invasion, which might be mediated, at least in part, through the Notch1-E-Cadherin pathway. Collectively, these findings suggest that targeting Notch1 has important therapeutic value in hepatocellular carcinoma. In this regard, comparative analysis of the secretome of HepG2 and HepG2 Notch1 depleted cells identified novel secreted proteins related to Notch1 expression. Soluble E-Cadherin (sE-Cad) and Thrombospondin-1 (Thbs1) were further validated in human serum as potential biomarkers to predict response to Notch1 inhibitors for a tailored individualized therapy.

The Notch3 Receptor and Its Intracellular Signaling-Dependent Oncogenic Mechanisms

During evolution, gene duplication of the Notch receptor suggests a progressive functional diversification. The Notch3 receptor displays a number of structural differences with respect to Notch1 and Notch2, most of which have been reported in the transmembrane and in the intracellular regions, mainly localized in the negative regulatory region (NRR) and trans-activation domain (TAD). Targeted deletion of Notch3 does not result in embryonic lethality, which is in line with its highly restricted tissue expression pattern. Importantly, deregulated Notch3 expression and/or activation, often results in disrupted cell differentiation and/or pathological development, most notably in oncogenesis in different cell contexts. Mechanistically this is due to Notch3-related genetic alterations or epigenetic or posttranslational control mechanisms. In this chapter we discuss the possible relationships between the structural differences and the pathological role of Notch3 in the control of mouse and human cancers. In future, targeting the unique features of Notch3-oncogenic mechanisms could be exploited to develop anticancer therapeutics.

Activated Notch signaling augments cell growth in hepatocellular carcinoma via up-regulating the nuclear receptor NR4A2

Hepatocellular carcinoma (HCC) is one of the most malignant cancers. Conventional therapies are limited due to the human liver being such a unique organ and easily showing side-effects. The unclear molecular mechanisms are tough challenges for scientists searching for new and effective anti-HCC targeting drugs. We identified that the nuclear receptor NR4A2 is a novel oncogene in HCC progression. In this study, we show that NR4A2 and the notch recceptor Notch1 were expressed highly in primary HCC tissues and immortal HCC cells by using qPCR, western blot and immuno-histochemistry assays. Both genes were observed to stimulate HCC cell proliferation, anti-apoptosis and cell cycle arrest by using cell proliferation assays and FACS assays. We also observed that the four notch receptor subtypes (Notch1-4) displayed different effects on HCC cell growth. The over-expression of Notch1 by transiently transfecting the intracellular domain of Notch1 (ICN1, Notch1 active form) increased the expression of NR4A2, with the knockdown of Notch1 decreasing NR4A2. This indicates that NR4A2 is one of the Notch-mediated downstream genes. Moreover, both NR4A2 and Notch1 suppressed the expression of tumor suppressors p21 and p63. These findings support that Notch1/NR4A2 co-regulate HCC cell functions by playing oncogenic roles and regulating the associated downstream signaling pathways. Novel Notch1/NR4A2-mediated oncogenic signaling may provide us a great opportunity for anti-HCC drug development.

Pivotal roles of glycogen synthase-3 in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most common cancers in the world, and represents the second most frequently cancer and third most common cause of death from cancer worldwide. At advanced stage, HCC is a highly aggressive tumor with a poor prognosis and with very limited response to common therapies. Therefore, there is still the need for new effective and well-tolerated therapeutic strategies. Molecular-targeted therapies hold promise for HCC treatment. One promising molecular target is the multifunctional serine/threonine kinase glycogen synthase kinase 3 (GSK-3). The roles of GSK-3β in HCC remain controversial, several studies suggested a possible role of GSK-3β as a tumor suppressor gene in HCC, whereas, other studies indicate that GSK-3β is a potential therapeutic target for this neoplasia. In this review, we will focus on the different roles that GSK-3 plays in HCC and its interaction with signaling pathways implicated in the pathogenesis of HCC, such as Insulin-like Growth Factor (IGF), Notch, Wnt/β-catenin, Hedgehog (HH), and TGF-β pathways. In addition, the pivotal roles of GSK3 in epithelial-mesenchymal transition (EMT), invasion and metastasis will be also discussed.

Vidatox 30 CH has tumor activating effect in hepatocellular carcinoma

Complementary and alternative medicine (CAM) is the term used to describe many kinds of products, practices, and systems that are not part of conventional medicine. Cancer patients usually do everything they can to combat the disease, manage its symptoms, and cope with the side effects of treatment. Unfortunately, patients who use CAM underestimate the risk of interaction with cancer therapy or worse they omit conventional therapy thus reducing the possibility of cancer remission. Herein we analyzed the effects of Vidatox 30 CH (venom extracted from the Junceus Rhopalurus scorpion) on hepatocellular carcinoma (HCC), the second leading cause of cancer-related deaths. We found out that Vidatox increases HCC proliferation and invasion whereas it does not seem to interact with sorafenib, the orally active multikinase inhibitor approved for the treatment of advanced hepatocellular carcinoma. Our results suggest that the concentration of Vidatox used in the present study has not anti-neoplastic effects and care must be taken in hiring Vidatox in patients with HCC.

Targeting Notch3 in Hepatocellular Carcinoma: Molecular Mechanisms and Therapeutic Perspectives

The Notch signaling pathway is a very conserved system that controls embryonic cell fate decisions and the maintenance of adult stem cells through cell to cell communication. Accumulating evidence support the relevance of Notch signaling in different human diseases and it is one of the most commonly activated signaling pathways in cancer. This review focuses mainly on the role of Notch3 signaling in hepatocellular carcinoma and its potential therapeutic applications against this malignancy. In this regard, the crosstalk between Notch and p53 may play an important role.

Understanding the role of PIN1 in hepatocellular carcinoma

PIN1 is a peptidyl-prolyl cis/trans isomerase that binds and catalyses isomerization of the specific motif comprising a phosphorylated serine or threonine residue preceding a proline (pSer/Thr-Pro) in proteins. PIN1 can therefore induce conformational and functional changes of its interacting proteins that are regulated by proline-directed serine/threonine phosphorylation. Through this phosphorylation-dependent prolyl isomerization, PIN1 fine-tunes the functions of key phosphoproteins (e.g., cyclin D1, survivin, β-catenin and x-protein of hepatitis B virus) that are involved in the regulation of cell cycle progression, apoptosis, proliferation and oncogenic transformation. PIN1 has been found to be over-expressed in many cancers, including human hepatocellular carcinoma (HCC). It has been shown previously that overexpression of PIN1 contributes to the development of HCC in-vitro and in xenograft mouse model. In this review, we first discussed the aberrant transcription factor expression, miRNAs dysregulation, PIN1 gene promoter polymorphisms and phosphorylation of PIN1 as potential mechanisms underlying PIN1 overexpression in cancers. Furthermore, we also examined the role of PIN1 in HCC tumourigenesis by reviewing the interactions between PIN1 and various cellular and viral proteins that are involved in β-catenin, NOTCH, and PI3K/Akt/mTOR pathways, apoptosis, angiogenesis and epithelial-mesenchymal transition. Finally, the potential of PIN1 inhibitors as an anti-cancer therapy was explored and discussed.

Diosmetin triggers cell apoptosis by activation of the p53/Bcl-2 pathway and inactivation of the Notch3/NF-κB pathway in HepG2 cells

Diosmetin (DIOS), a flavonoid compound, is abundant in Citrus limon. Emerging studies have shown that DIOS is an effective compound implicated in multiple types of cancer. However, whether DIOS serves a role in hepatocellular carcinoma (HCC) is still obscure. HepG2 cells were used in the present study, and it was observed that DIOS exhibited antitumor activity against liver cancer cells. Western blotting was performed to evaluate cell apoptosis and survival-associated proteins, and the results demonstrated that DIOS treatment resulted in the activation of the p53-dependent apoptosis pathway. Our results revealed that DIOS caused inhibition of the nuclear factor (NF)-κB signaling pathway and downregulation of Notch3 receptor. Furthermore, by using small hairpin RNA-Notch3, it was confirmed that DIOS inhibited the NF-κB signaling pathway by inactivation of Notch3. In conclusion, the present results demonstrated that DIOS triggered cell apoptosis by activation of the p53 signaling pathway and inhibited the NF-κB cell survival pathway by downregulation of Notch3 receptor expression. DIOS is a potential agent for prevention of HCC.

Doxorubicin induces apoptosis by targeting Madcam1 and AKT and inhibiting protein translation initiation in hepatocellular carcinoma cells

Doxorubicin (Doxo) is one of the most widely used chemotherapeutic drugs for patients with hepatocellular carcinoma (HCC). Doxo is a DNA intercalating drug that inhibits topoisomerase II. Thereby Doxo has the ability to block DNA replication and induce apoptosis. However, the other targets and mechanisms through which Doxo induces apoptosis to treat HCC still remain unknown. Here, we identified Mucosal vascular addressin cell adhesion molecule 1 (Madcam1) as a potential Doxo target because Madcam1 overexpression suppressed, while Madcam1 depletion stimulated Doxo-induced apoptosis. Furthermore, we first revealed that Doxo can induce apoptosis by blocking protein translation initiation. In contrast, Madcam1 activated protein translation through an opposite mechanism. We also found de-phosphorylation of AKT may be an important pro-apoptotic event that is triggered by Doxo-induced Madcam1 down-regulation. Finally, we revealed that Madcam1 promoted increased AKT phosphorylation, which is essential for maintaining the sensitivity of HCC cells to Doxo treatment. Taken together, we uncovered a potential mechanism for Doxo-induced apoptosis in HCC treatment through targeting Madcam1 and AKT and blocking protein translation initiation.

Notch2 is a crucial regulator of self-renewal and tumorigenicity in human hepatocellular carcinoma cells

The Notch pathway plays an important role in both stem cell biology and cancer. Notch2 was reported to be upregulated in human hepatocellular carcinoma (HCC) tissues. However, the biological function of Notch2 in human HCC cells has not yet been documented. The aim of this study was to investigate its possible function on the progression of human HCC cells. The expression of Notch2 was detected in four human HCC cell lines by western blotting. Next, Notch2 was knocked down by small interference RNA (siRNA) in human HCC cells. The role of Notch2 in human HCC cells was investigated by cell proliferation assay, colony formation assay, chemoresistance and xenograft formation assay. In the present study, western blotting revealed that the expression of Notch2 was upregulated in human HCC cell lines. Genetic depletion of Notch2 in HCC cells not only resulted in significantly inhibited proliferation, cell cycle progression and colony formation ability but also increased its sensitivity to 5-fluorouracil (5-FU) compared with controls. In addition, upregulation of Notch2 was discovered in CD90 positive HCC cells, CD90 is a marker of hepatic stem cells. Most importantly, knockdown of Notch2 in HCC cells impaired the tumor formation in vivo. Taken together, our findings indicate that Notch2 may confer stemness properties in HCC; downregulation of Notch2 inhibited the proliferation and tumor formation of HCC cells and increase their sensitivity to 5-FU, suggesting Notch2 as a potential therapeutic target for HCC.

Epithelial-mesenchymal transition and related signaling pathways in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most common forms of liver cancer and the third leading cause of cancer-related mortality in the world. Although numerous therapeutic strategies have been employed to treat this fatal disease, the prognosis of HCC patients remains dismal with a low 5-year survival rate of approximately 30%. Postoperative recurrence and metastasis of HCC are the leading cause of poor prognosis. Metastasis has been thought to rely on non-motile epithelial tumor cells acquiring characteristics of mesenchymal cells, which are more migratory. This change is known as the epithelial-to-mesenchymal transition (EMT). EMT has been considered one of the main reasons for the invasion and metastasis of HCC. Notably, increasing evidence indicates that several signaling pathways participate in the regulation of EMT in HCC. In the current review, we will discuss the current progress in research of EMT and its related signaling pathways in HCC.

Actin-like 6A predicts poor prognosis of hepatocellular carcinoma and promotes metastasis and epithelial-mesenchymal transition

Hepatocellular carcinoma (HCC) is one of the most lethal cancers worldwide because of metastasis. Epithelial-mesenchymal transition (EMT) is widely considered to be crucial to the invasion-metastasis cascade during cancer progression. Actin-like 6A (ACTL6A) is initially verified important for cell proliferation, differentiation, and migration. In this study, we find that ACTL6A plays an essential role in metastasis and EMT of HCC. ACTL6A expression is up-regulated in HCC cells and tissues. A high level of ACTL6A in HCCs is correlated with aggressive clinicopathological features and is an independent poor prognostic factor for overall and disease-free survival of HCC patients. Ectopic expression of ACTL6A markedly promotes HCC cells migration, invasion, as well as EMT in vitro and promotes tumor growth and metastasis in the mouse xenograft model. Opposite results are observed when ACTL6A is knocked down. Mechanistically, ACTL6A promotes metastasis and EMT through activating Notch signaling. ACTL6A knockdown has the equal blockage effect as the Notch signaling inhibitor, N-[N-(3,5-difluorophenacetyl)-L-alanyl]-S-phenylglycine t-butylester, in HCC cells. Further studies indicate that ACTL6A might manipulate SRY (sex determining region Y)-box 2 (SOX2) expression and then activate Notch1 signaling.

CONCLUSIONS

ACTL6A promotes metastasis and EMT by SOX2/Notch1 signaling, indicating a prognostic biomarker candidate and a potential therapeutic target for HCC.

Interferon-α2b gene-modified human bone marrow mesenchymal stem cells inhibit hepatocellular carcinoma by reducing the Notch1 levels

AIMS

Hepatocellular carcinoma (HCC) is the most common liver cancer worldwide. IFN-α has been used in clinics as a potential therapeutic strategy to treat HCC. In spite of the therapeutic effects, IFN-α caused many side effects due to its short half-life and high dose. Here, we aim to detect the anti-tumor effect of a novel gene delivery system - IFN-α2b gene-modified human bone marrow mesenchymal stem cells (BMSCs) in HCC.

MAIN METHODS

Two HCC cell lines, HepG2 and Huh7 were used in the current study. The secretion of IFN-α2b in the BMSC cultured conditioned media (CM) was measured by ELISA. The cell cycle was determined by flow cytometry. The Xenografted NOD/SCID mouse tumor model was generated by subcutaneous inoculation with HepG2 cells.

KEY FINDINGS

We found that the IFN-α2b-modified BMSC (BMSC/IFN-α2b) could express IFN-α2b stably. The CM from BMSC/IFN-α2b inhibited the proliferation of HCC cells with a much lower growth rate compared with BMSC/vector-CM or DMEM culture group. We further demonstrated that the population of G2/M phase was higher in BMSC/IFN-α2b-CM treated cells than the other two groups. In addition, BMSC/IFN-α2b could significantly inhibit tumor growth in NOD/SCID mice. Moreover, we found that BMSC/IFN-α2b-CM could significantly decrease the mRNA and protein levels of Notch signaling molecules of HCC in vitro and in vivo.

SIGNIFICANCE

Our data demonstrated that BMSC/IFN-α2b could significantly inhibit HCC cell growth through negatively regulating the Notch signaling, which suggested that IFN-α2b-modified BMSC may be used as an effective therapeutic strategy for hepatomas.

Suppression of p53 by Notch3 is mediated by Cyclin G1 and sustained by MDM2 and miR-221 axis in hepatocellular carcinoma

To successfully target Notch receptors as part of a multidrug anticancer strategy, it will be essential to fully characterize the factors that are modulated by Notch signaling. We recently reported that Notch3 silencing in HCC results in p53 up-regulation in vitro and, therefore, we focused on the mechanisms that associate Notch3 to p53 protein expression. We explored the regulation of p53 by Notch3 signalling in three HCC cell lines HepG2, SNU398 and Hep3B.We found that Notch3 regulates p53 at post-transcriptional level controlling both Cyclin G1 expression and the feed-forward circuit involving p53, miR-221 and MDM2. Moreover, our results were validated in human HCCs and in a rat model of HCC treated with Notch3 siRNAs. Our findings are becoming an exciting area for further in-depth research toward targeted inactivation of Notch3 receptor as a novel therapeutic approach for increasing the drug-sensitivity, and thereby improving the treatment outcome of patients affected by HCC. Indeed, we proved that Notch3 silencing strongly increases the effects of Nutilin-3.With regard to therapeutic implications, Notch3-specific drugs could represent a valuable strategy to limit Notch signaling in the context of hepatocellular carcinoma over-expressing this receptor.

The Histone Deacetylase Inhibitor Vaproic Acid Induces Cell Growth Arrest in Hepatocellular Carcinoma Cells via Suppressing Notch Signaling

Hepatocellular carcinoma (HCC) is a type of malignant cancer. Notch signaling is aberrantly expressed in HCC tissues with more evidence showing that this signaling plays a critical role in HCCs. In the present study, we investigate the effects of the anti-convulsant drug valproic acid (VPA) in HCC cells and its involvement in modulating Notch signaling. We found that VPA, acting as a histone deacetylase (HDAC) inhibitor, induced a decrease in HDAC4 and an increase in acetylated histone 4 (AcH4) and suppressed HCC cell growth. VPA also induced down-regulation of Notch signaling via suppressing the expression of Notch1 and its target gene HES1, with an increase of tumor suppressor p21 and p63. Furthermore, Notch1 activation via overexpressing Notch1 active form ICN1 induced HCC cell proliferation and anti-apoptosis, indicating Notch signaling played an oncogenic role in HCC cells. Meanwhile, VPA could reverse Notch1-induced increase of cell proliferation. Interestingly, VPA was also observed to stimulate the expression of G protein-coupled somatostatin receptor type 2 (SSTR2) that has been used in receptor-targeting therapies. This discovery supports a combination therapy of VPA with the SSTR2-targeting agents. Our in vitro assay did show that the combination of VPA and the peptide-drug conjugate camptothecin-somatostatin (CPT-SST) displayed more potent anti-proliferative effects on HCC cells than did each alone. VPA may be a potential drug candidate in the development of anti-HCC drugs via targeting Notch signaling, especially in combination with receptor-targeting cytotoxic agents.

Molecular signalling in hepatocellular carcinoma: Role of and crosstalk among WNT/ß-catenin, Sonic Hedgehog, Notch and Dickkopf-1

Hepatocellular carcinoma is the sixth most common cancer worldwide. In the majority of cases, there is evidence of existing chronic liver disease from a variety of causes including viral hepatitis B and C, alcoholic liver disease and nonalcoholic steatohepatitis. Identification of the signalling pathways used by hepatocellular carcinoma cells to proliferate, invade or metastasize is of paramount importance in the discovery and implementation of successfully targeted therapies. Activation of Wnt/β-catenin, Notch and Hedgehog pathways play a critical role in regulating liver cell proliferation during development and in controlling crucial functions of the adult liver in the initiation and progression of human cancers. β-catenin was identified as a protein interacting with the cell adhesion molecule E-cadherin at the cell-cell junction, and has been shown to be one of the most important mediators of the Wnt signalling pathway in tumourigenesis. Investigations into the role of Dikkopf-1 in hepatocellular carcinoma have demonstrated controversial results, with a decreased expression of Dickkopf-1 and soluble frizzled-related protein in various cancers on one hand, and as a possible negative prognostic indicator of hepatocellular carcinoma on the other. In the present review, the authors focus on the Wnt⁄β-catenin, Notch and Sonic Hedgehog pathways, and their interaction with Dikkopf-1 in hepatocellular carcinoma.

RBP-J-interacting and tubulin-associated protein induces apoptosis and cell cycle arrest in human hepatocellular carcinoma by activating the p53-Fbxw7 pathway

Aberrant Notch signaling is observed in human hepatocellular carcinoma (HCC) and has been associated with the modulation of cell growth. However, the role of Notch signaling in HCC and its underlying mechanism remain elusive. RBP-J-interacting and tubulin-associated (RITA) mediates the nuclear export of RBP-J to tubulin fibers and downregulates Notch-mediated transcription. In this study, we found that RITA overexpression increased protein expression of p53 and Fbxw7 and downregulated the expression of cyclin D1, cyclin E, CDK2, Hes-1 and NF-κB p65. These changes led to growth inhibition and induced G0/G1 cell cycle arrest and apoptosis in SMMC7721 and HepG2 cells. Our findings indicate that RITA exerts tumor-suppressive effects in hepatocarcinogenesis through induction of G0/G1 cell cycle arrest and apoptosis and suggest a therapeutic application of RITA in HCC.

Notch3 inhibition enhances sorafenib cytotoxic efficacy by promoting GSK3b phosphorylation and p21 down-regulation in hepatocellular carcinoma

Sorafenib (Nexavar), a multiple kinase inhibitor, is the only clinically approved drug for patients with advanced HCC. However, its therapeutic success is limited by the emergence of drug resistance. Here we found that p21 and pGSK3β^Ser9 are major players in the resistance to sorafenib. We recently reported that aberrant Notch3 expression in HCC contributes to doxorubicin resistance in vitro and, therefore, we focused on the mechanisms that associate Notch3 to acquired drug resistance. In this study we first found that Notch3 inhibition significantly increased the apoptosis inducing effect of sorafenib in HCC cells via specific down-regulation of p21 and up-regulation of pGSK3β^Ser9. Using a mouse xenograft model we further found that Notch3 depletion combined with 21 days of sorafenib treatment exerts a substantial antitumor effect in vivo. Interestingly, we showed that, upon exposure to sorafenib treatment, Notch3 depleted xenografts maintain lower levels of p21 and higher levels of pGSK3β^Ser9 than control xenografts. Thus, this study demonstrated that inhibition of Notch3 signaling prevents HCC-mediate drug resistance and sensitizes HCC cells to sorafenib. Finally, we validated our in vitro and in vivo results in primary human HCCs showing that Notch3 protein expression positively correlated with p21 protein expression and negatively correlated with pGSK3β^Ser9 expression. In conclusion, the results presented in this study demonstrated that Notch3 silencing enhances the effect of sorafenib by overcoming drug resistance. Notch3 inhibition in combination with sorafenib can be a promising strategy for treatment of HCC.

Notch1 promotes hepatitis B virus X protein-induced hepatocarcinogenesis via Wnt/β-catenin pathway

Hepatitis B virus X protein (HBx) is implicated in the pathogenesis of hepatocellular carcinoma (HCC) via a network of signaling pathways. Notch pathway is a major member of the network. Notch signaling may generate opposing effect in different steps of carcinogenesis, depending on the tumor cell type and the status of other signaling pathways, such as Wnt signaling pathway. Our previous studies have shown that activated Notch1 signaling is required for HBx to promote proliferation and survival of human hepatic cell line L02. However, the exact mechanisms remain vague. Here, we used L02/HBx cell lines as a cell model to study the relationship between Notch and Wnt/β-catenin pathways in promoting proliferation. We observed that activated Notch1 and Wnt/β-catenin signaling pathways and L02 cell malignant transformation were induced by HBx. Inhibition of the Notch1 pathway decreased the activation of Wnt/β-catenin pathway and cell proliferation, while inhibition of the Wnt/β-catenin pathway impaired cell proliferation, but did not significantly affect Notch1 signaling pathway in L02/HBx cells. Furthermore, inhibition of the Wnt/β-catenin pathway overcame the inhibition effect of knockdown Notch1 on proliferation and survival in L02/HBx cells. Additionally, the activity of Wnt/β-catenin signaling appears to be consistent with Fzd10 expression. Therefore, we demonstrate that Wnt signaling is downstream of the Notch pathway in regulating proliferation of L02/HBx cells, and which may be related to Fzd10 instead of Fzd7. These data suggest a new model of HBx-related HCC via cooperation between Wnt and Notch pathways.