Notch1 is overexpressed in human intrahepatic cholangiocarcinoma and is associated with its proliferation, invasiveness and sensitivity to 5-fluorouracil in vitro

Molecular biology of cholangiocarcinoma and its implications for targeted therapy in patient management

Cholangiocarcinoma (CCA) remains a devastating malignancy and a significant challenge to treat. The majority of CCA patients are diagnosed at an advanced stage, making the disease incurable in most cases. The advent of high-throughput genetic sequencing has significantly improved our understanding of the molecular biology underpinning cancer. The identification of 'druggable' genetic aberrations and the development of novel targeted therapies against them is opening up new treatment strategies. Currently, 3 targeted therapies are approved for use in CCA; Ivosidenib in patients with IDH1 mutations and Infigratinib/Pemigatinib in those with FGFR2 fusions. As our understanding of the biology underpinning CCA continues to improve it is highly likely that additional targeted therapies will become available in the near future. This is important, as it is thought up to 40 % of CCA patients harbour a potentially actionable mutation. In this review we provide an overview of the molecular pathogenesis of CCA and highlight currently available and potential future targeted treatments.

Targeting the Ajuba/Notch axis increases the sensitivity of colon cancer cells to 5-fluorouracil

Objective

Colorectal cancer is severely challenging because of the insufficient understanding of the mechanism underlying its resistance to clinical chemotherapy. The purpose of our study is to investigate the role of the LIM protein Ajuba (JUB) in the chemoresistance of colon cancer and its potential effect on clinical treatment.

Material and Methods

The protein levels of JUB in colon cancer tissues were evaluated using Western blot analysis and immunohistochemistry assays. The correlation between JUB and the prognosis of patients with colorectal cancer was determined using Kaplan-Meier plot analysis. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assays were employed to determine the 50% inhibitory concentration of 5-fluorouracil (5-FU) and thus assess the effect of JUB on the effectiveness of 5-FU. In addition, the rate of cellular apoptosis was measured using fluorescence-activated cell sorting assays. Side population and sphere formation analyses were conducted to determine the role of JUB in promoting the stem cell-like traits of colon cancer cells. In vivo assays were performed and detect whether the downregulation of JUB induces 5-FU sensitivity. Moreover, luciferase and Western blot assays were employed to uncover the mechanism through which JUB promotes chemoresistance in colon cancer.

Results

JUB expression was upregulated in chemoresistant colon cancer (P < 0.001) and correlated with relapse-free survival (P = 0.000002). Functionally, the upregulation of JUB conferred 5-FU resistance to colon cancer cells in vitro, whereas the downregulation of JUB induced 5-FU sensitivity in colon cancer cells in vivo. The high expression of JUB promoted the tumorigenic capability of colon cancer cells. Furthermore, the increased expression of JUB activated multiple downstream genes of the Notch signaling pathway with increased expression in JUB-overexpressing cells but reduced expression in JUB-silenced cells. Importantly, the inhibition of Notch signaling using a small-molecule inhibitor significantly suppressed JUB-induced chemoresistance.

Conclusion

Results suggest that JUB plays an important role and may serve as a biomarker for the clinical treatment of patients with 5-FU-resistant colon cancer.

Notch signaling pathway in cancer: from mechanistic insights to targeted therapies

Notch signaling, renowned for its role in regulating cell fate, organ development, and tissue homeostasis across metazoans, is highly conserved throughout evolution. The Notch receptor and its ligands are transmembrane proteins containing epidermal growth factor-like repeat sequences, typically necessitating receptor-ligand interaction to initiate classical Notch signaling transduction. Accumulating evidence indicates that the Notch signaling pathway serves as both an oncogenic factor and a tumor suppressor in various cancer types. Dysregulation of this pathway promotes epithelial-mesenchymal transition and angiogenesis in malignancies, closely linked to cancer proliferation, invasion, and metastasis. Furthermore, the Notch signaling pathway contributes to maintaining stem-like properties in cancer cells, thereby enhancing cancer invasiveness. The regulatory role of the Notch signaling pathway in cancer metabolic reprogramming and the tumor microenvironment suggests its pivotal involvement in balancing oncogenic and tumor suppressive effects. Moreover, the Notch signaling pathway is implicated in conferring chemoresistance to tumor cells. Therefore, a comprehensive understanding of these biological processes is crucial for developing innovative therapeutic strategies targeting Notch signaling. This review focuses on the research progress of the Notch signaling pathway in cancers, providing in-depth insights into the potential mechanisms of Notch signaling regulation in the occurrence and progression of cancer. Additionally, the review summarizes pharmaceutical clinical trials targeting Notch signaling for cancer therapy, aiming to offer new insights into therapeutic strategies for human malignancies.

Sensitization of cholangiocarcinoma cells to chemotherapy through BCRP inhibition with β-caryophyllene oxide

Cholangiocarcinomas (CCAs) are cancers originated in the biliary tree, which are characterized by their high mortality and marked chemoresistance, partly due to the activity of ATP-binding cassette (ABC) export pumps, whose inhibition has been proposed as a strategy for enhancing the response to chemotherapy. We have previously shown that β-caryophyllene oxide (CRYO) acts as a chemosensitizer in hepatocellular carcinoma by inhibiting ABCB1, MRP1, and MRP2. Here, we have evaluated the usefulness of CRYO in inhibiting BCRP and improving the response of CCA to antitumor drugs. The TCGA-CHOL cohort (n = 36) was used for in silico analysis. BCRP expression (mRNA and protein) was assayed in samples from intrahepatic (iCCA) and extrahepatic (eCCA) tumors (n = 50) and CCA-derived cells (EGI-1 and TFK-1). In these cells, BCRP-dependent mitoxantrone transport was determined by flow cytometry. At non-toxic concentrations, CRYO inhibited BCRP function, which enhanced the cytostatic effect of drugs used in the treatment of CCA. The BCRP ability to confer resistance to a panel of antitumor drugs was determined in Chinese hamster ovary (CHO) cells with stable BCRP expression. At non-toxic concentrations, CRYO markedly reduced BCRP-induced resistance to known substrate drugs (mitoxantrone and SN-38) and cisplatin, gemcitabine, sorafenib, and 5-FU but not oxaliplatin. Neither CRYO nor cisplatin alone significantly affected the growth of BCRP-expressing tumors subcutaneously implanted in immunodeficient mice. In contrast, intratumor drug content was enhanced when administered together, and tumor growth was inhibited. In sum, the combined treatment of drugs exported by BCRP with CRYO can improve the response to chemotherapy in CCA patients.

Tspan15-ADAM10 signalling enhances cancer stem cell-like properties and induces chemoresistance via Notch1 activation in ICC

BACKGROUND & AIMS

Notch1 activation promotes ICC progression and is associated with chemoresistance; however, therapies directly targeting Notch1 showed severe adverse effects. Notch1 activation is mediated by ADAM10, a molecular scissor that separates the target protein from its substrates in the cell membrane. Tspan15 regulates ADAM10 function, but the role of Tspan15 in ICC progression is unclear.

METHODS

Tspan15, ADAM10, and Notch1 expression and activation in fresh surgical specimens from 80 ICC patients and ICC cells were evaluated by immunohistochemistry, RT-PCR, western blotting, and flow cytometry.

RESULTS

Tspan15 expression was increased in ICC compared with adjacent liver tissue, and high Tspan15 expression was an independent factor for poor prognosis. In ICC with high Tspan15 expression, vascular invasion, lymph node metastasis, and haematogenous recurrence were increased. Tspan15 was co-expressed with ADAM10 in ICC, and associated with the expression of stemness and EMT markers. In ICC cells, Tspan15 induced ADAM10 activation by mediating the translocation of activated m-ADAM10 from the cytoplasm to the surface of the cell membrane, which further activated Notch1 by separating the intracellular domain of Notch1 from its extracellular domain, leading to enhancement of CSC-like properties and EMT. This signalling was associated with enhanced chemoresistance against gemcitabine and cisplatin. Inhibition of Tspan15 or ADAM10 is a promising therapeutic strategy in ICC, as Tspan15 or ADAM10 knockdown or treatment with ADAM10 inhibitor reduced chemoresistance and invasiveness by suppressing Notch1-mediated CSC-like properties and EMT.

CONCLUSIONS

Tspan15-ADAM10-Notch1 signalling is associated with aggressive tumour progression and poor prognosis in ICC.

NOTCH signalling - a core regulator of bile duct disease?

The Notch signalling pathway is an evolutionarily conserved mechanism of cell-cell communication that mediates cellular proliferation, fate determination and maintenance of stem/progenitor cell populations across tissues. Although it was originally identified as a critical regulator of embryonic liver development, NOTCH signalling activation has been associated with the pathogenesis of a number of paediatric and adult liver diseases. It remains unclear, however, what role NOTCH actually plays in these pathophysiological processes and whether NOTCH activity represents the reactivation of a conserved developmental programme that is essential for adult tissue repair. In this Review, we explore the concepts that NOTCH signalling reactivation in the biliary epithelium is a reiterative and essential response to bile duct damage and that, in disease contexts in which biliary epithelial cells need to be regenerated, NOTCH signalling supports ductular regrowth. Furthermore, we evaluate the recent literature on NOTCH signalling as a critical factor in progenitor-mediated hepatocyte regeneration, which indicates that the mitogenic role for NOTCH signalling in biliary epithelial cell proliferation has also been co-opted to support other forms of epithelial regeneration in the adult liver.

Implication of Ferroptosis in Cholangiocarcinoma: A Potential Future Target?

Cholangiocarcinoma (CCA), the second most common liver neoplasm, has a poor overall 5-year survival rate of less than 10%. A deeper understanding of the molecular pathogenesis contributing to CCA progression is essential for developing better therapeutic approaches to manage this disease. Ferroptosis, an oxidative iron-dependent form of regulated cell death, has been reported to be involved in tumorigenesis and progression. In particular, ferroptosis and inflammation, which are common issues in cholangiocarcinogenesis and CCA development, might be in concert with disease progression. Notably, the key feature of cancer cells is "iron addiction", which is crucial for the high metabolic demand in carcinogenesis and cancer progression. Additionally, iron metabolism is of great importance in ferroptosis. Moreover, that cancer cells are vulnerable to ferroptosis might be a possible mechanism of CCA development. Although the underlying mechanism of how ferroptosis is implicated in CCA development requires further investigation, developing a new strategy combined with a pro-ferroptotic treatment would be an exciting CCA treatment approach in the future.

Expression of Chemoresistance-Associated ABC Proteins in Hepatobiliary, Pancreatic and Gastrointestinal Cancers

Simple Summary

One-third of the approximately 10 million deaths yearly caused by cancer worldwide are due to hepatobiliary, pancreatic, and gastrointestinal tumors. One primary reason for this high mortality is the lack of response of these cancers to pharmacological treatment. More than 100 genes have been identified as responsible for seven mechanisms of chemoresistance, but only a few of them play a critical role. These include ABC proteins (mainly MDR1, MRP1-6, and BCRP), whose expression pattern greatly determines the individual sensitivity of each tumor to pharmacotherapy.

Abstract

Hepatobiliary, pancreatic, and gastrointestinal cancers account for 36% of the ten million deaths caused by cancer worldwide every year. The two main reasons for this high mortality are their late diagnosis and their high refractoriness to pharmacological treatments, regardless of whether these are based on classical chemotherapeutic agents, targeted drugs, or newer immunomodulators. Mechanisms of chemoresistance (MOC) defining the multidrug resistance (MDR) phenotype of each tumor depend on the synergic function of proteins encoded by more than one hundred genes classified into seven groups (MOC1-7). Among them, the efflux of active agents from cancer cells across the plasma membrane caused by members of the superfamily of ATP-binding cassette (ABC) proteins (MOC-1b) plays a crucial role in determining tumor MDR. Although seven families of human ABC proteins are known, only a few pumps (mainly MDR1, MRP1-6, and BCRP) have been associated with reducing drug content and hence inducing chemoresistance in hepatobiliary, pancreatic, and gastrointestinal cancer cells. The present descriptive review, which compiles the updated information on the expression of these ABC proteins, will be helpful because there is still some confusion on the actual relevance of these pumps in response to pharmacological regimens currently used in treating these cancers. Moreover, we aim to define the MOC pattern on a tumor-by-tumor basis, even in a dynamic way, because it can vary during tumor progression and in response to chemotherapy. This information is indispensable for developing novel strategies for sensitization.

[The role of molecular genetic factors in the development of cholangiocellular carcinoma]

The article lists the main inducers of cholangiocarcinogenesis. The main inflammatory mediators (IL-6, nitric oxide, COX2) have been considered. Data on the study of gene mutations in cholangiocarcinomas are presented. The spectrum of genetic mutations depends on the biliary cancer origin (FGFR2 with intrahepatic cholangiocarcinoma, PRKACA, PRKACB with extrahepatic cholangiocarcinoma). Mutations in the KRAS, TP53, ARIAD1A genes are common in extrahepatic bile duct cancer. The role of epigenetic changes such as DNA hypermethylation, histone modifications, chromatin remodeling, as well as disturbances in miRNA expression is presented. A number of epigenetic features, such as the presence of a TP53 mutations with hypermethylation of p14ARF, DAPK, and/or ASC, correlate with a more aggressive course of the disease. The role of the SOX17 gene in the development of drug resistance is highlighted. The study of the molecular genetic features of extrahepatic bile duct cancer can help to better understand the pathogenesis of this type of tumor, to establish new prognostic and diagnostic markers of the disease.

Overcome Drug Resistance in Cholangiocarcinoma: New Insight Into Mechanisms and Refining the Preclinical Experiment Models

Cholangiocarcinoma (CCA) is an aggressive tumor characterized by a poor prognosis. Therapeutic options are limited in patients with advanced stage of CCA, as a result of the intrinsic or acquired resistance to currently available chemotherapeutic agents, and the lack of new drugs entering into clinical application. The challenge in translating basic research to the clinical setting, caused by preclinical models not being able to recapitulate the tumor characteristics of the patient, seems to be an important reason for the lack of effective and specific therapies for CCA. So, there seems to be two ways to improve patient outcomes. The first one is developing the combination therapies based on a better understanding of the mechanisms contributing to the resistance to currently available chemotherapeutic agents. The second one is developing novel preclinical experimental models that better recapitulate the genetic and histopathological features of the primary tumor, facilitating the screening of new drugs for CCA patients. In this review, we discussed the evidence implicating the mechanisms underlying treatment resistance to currently investigated drugs, and the development of preclinical experiment models for CCA.

Signaling Pathways Involved in 5-FU Drug Resistance in Cancer

Anti-metabolite drugs prevent the synthesis of essential cell growth compounds. 5-fluorouracil is used as an anti-metabolic drug in various cancers in the first stage of treatment. Unfortunately, in some cancers, 5-fluorouracil has low effectiveness because of its drug resistance. Studies have shown that drug resistance to 5-fluorouracil is due to the activation of specific signaling pathways and increased expressions of enzymes involved in drug metabolites. However, when 5-fluorouracil is used in combination with other drugs, the sensitivity of cancer cells to 5-fluorouracil increases, and the effect of drug resistance is reversed. This study discusses how the function of 5-fluorouracil in JAK/STAT, Wnt, Notch, NF-κB, and hedgehogs in some cancers.

Inflammatory pathways and cholangiocarcinoma risk mechanisms and prevention

Cholangiocarcinoma (CCA), a neoplasm burdened by a poor prognosis and currently lacking adequate therapeutic treatments, can originate at different levels of the biliary tree, in the intrahepatic, hilar, or extrahepatic area. The main risk factors for the development of CCA are the presence of chronic cholangiopathies of various etiology. To date, the most studied prodromal diseases of CCA are primary sclerosing cholangitis, Caroli's disease and fluke infestations, but other conditions, such as metabolic syndrome, nonalcoholic fatty liver disease and obesity, are emerging as associated with an increased risk of CCA development. In this review, we focused on the analysis of the pro-inflammatory mechanisms that induce the development of CCA and on the role of cells of the immune response in cholangiocarcinogenesis. In very recent times, these cellular mechanisms have been the subject of emerging studies aimed at verifying how the modulation of the inflammatory and immunological responses can have a therapeutic significance and how these can be used as therapeutic targets.

Notch signaling in the pathogenesis, progression and identification of potential targets for cholangiocarcinoma (Review)

Cholangiocarcinoma (CCA) is an aggressive type of bile duct cancer that is characterized by a high mortality rate due to its late diagnosis and ineffective treatment. The aim of the present systematic review was to analyze the association between Notch signaling and CCA in terms of its pathogenesis, progression and potential treatment targets. Relevant information was gathered from the PubMed, ScienceDirect and Scopus databases using the search terms 'cholangiocarcinoma' AND 'Notch signaling'. Of the 90 articles identified, 28 fulfilled the eligibility criteria and were included in the analysis. It was concluded that overexpression/upregulation of Notch ligands, such as Jagged1 and Notch receptors (Notch1, Notch2 and Notch3), as well as upregulation of the upstream Notch signaling pathway, promoted CCA development and progression. In addition, downregulation of Notch1 signaling through several possible interventions appears to be a promising strategy for inhibition of CCA development and progression. Therefore, the Notch signaling pathway may be considered as a potential target for CCA control.

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.

Genomic characterization of rare molecular subclasses of hepatocellular carcinoma

Primary liver cancer, consisting of both cholangiocarcinoma (CCA) and hepatocellular carcinoma (HCC), is the second leading cause of cancer deaths worldwide. Our goal is to genomically characterize rare HCC subclasses to provide insight into disease biology. Leveraging The Cancer Genome Atlas (TCGA) to perform a combined analysis of CCA (n = 36) and HCC (n = 275), we integrated multiple genomic platforms, to assess transcriptional profiles, mutational signatures, and copy number patterns to uncover underlying etiology and linage specific patterns. We identified two molecular classes distinct from prototypical HCC tumors. The first, CCA-Like, although histologically indistinguishable from HCC, had enrichment of CCA mutations (IDH1, BAP1), mutational signatures, and transcriptional patterns (SOX9, KRT19). CCA-Like, however, retained a copy number landscape similar to HCC, suggesting a hepatocellular linage. The second, Blast-Like, is enriched in TP53 mutations, HBV infection, exposure related mutational signatures and transcriptionally similar to hepatoblasts. Although these subclasses are molecularly distinct, they both have a worse progression-free survival compared to classical HCC tumors, yet are clinically treated the same. The identification of and characterization of CCA-Like and Blast-Like subclasses advance our knowledge of HCC as well as represents an urgent need for the identification of class specific biomarkers and targeted therapy.

Notch Signaling Pathway in Pancreatobiliary Tumors

Background and Objectives: The Notch signaling pathway plays an important role both in the development of the ductal systems of the pancreas and the bile ducts as well as in cancer development and progression. The aim of this study was to examine the expression of central proteins of the Notch signaling pathway in pancreatobiliary tumors and its influence on patient survival. Materials and Methods: We compared the receptors (Notch1, Notch4), activating splicing factors (ADAM17), and target genes (HES1) of the Notch pathway and progenitor cell markers with relevance for the Notch signaling pathway (CD44, MSI1) between pancreatic adenocarcinomas (PDAC, n = 14), intrahepatic cholangiocarcinoma (iCC, n = 24), and extrahepatic cholangiocarcinoma (eCC, n = 22) cholangiocarcinomas via immunohistochemistry and ImageJ software-assisted analysis. An Immunohistochemistry (IHC)-score was determined by the percentage and intensity of stained (positive) cells (scale 0–7) and normal and malignant tissue was compared. In the IHC results, patients’ (gender, age) and tumor (TNM Classification of Malignant Tumors, Union Internationale contre le Cancer (UICC) stages, grading, and lymphangitic carcinomatosa) characteristics were correlated to patient survival. Results: For eCC, the expression of CD44 (p = 0.043, IHC-score 3.94 vs. 3.54) and for iCC, the expression of CD44 (p = 0.026, IHC-score 4.04 vs. 3.48) and Notch1 (p < 0.001, IHC-score 2.87 vs. 1.78) was significantly higher in the tumor compared to non-malignant tissue. For PDAC, the expression of ADAM17 (p = 0.008, IHC-score 3.43 vs. 1.73), CD44 (p = 0.012, IHC-score 3.64 vs. 2.27), Notch1 (p = 0.012, IHC-score 2.21 vs. 0.64), and Notch4 (p = 0.008, IHC-score 2.86 vs. 0.91) was significantly higher in the tumor tissue. However, none of the analyzed Notch-signaling related components showed an association to patient survival. Conclusion: A significant overexpression of almost all studied components of the Notch signaling pathway can be found in the tumor tissue, however, without a significant influence on patient survival. Therefore, further studies are warranted to draw conclusions on Notch pathway’s relevance for patient survival.

Cholangiocarcinoma 2020: the next horizon in mechanisms and management

Cholangiocarcinoma (CCA) includes a cluster of highly heterogeneous biliary malignant tumours that can arise at any point of the biliary tree. Their incidence is increasing globally, currently accounting for ~15% of all primary liver cancers and ~3% of gastrointestinal malignancies. The silent presentation of these tumours combined with their highly aggressive nature and refractoriness to chemotherapy contribute to their alarming mortality, representing ~2% of all cancer-related deaths worldwide yearly. The current diagnosis of CCA by non-invasive approaches is not accurate enough, and histological confirmation is necessary. Furthermore, the high heterogeneity of CCAs at the genomic, epigenetic and molecular levels severely compromises the efficacy of the available therapies. In the past decade, increasing efforts have been made to understand the complexity of these tumours and to develop new diagnostic tools and therapies that might help to improve patient outcomes. In this expert Consensus Statement, which is endorsed by the European Network for the Study of Cholangiocarcinoma, we aim to summarize and critically discuss the latest advances in CCA, mostly focusing on classification, cells of origin, genetic and epigenetic abnormalities, molecular alterations, biomarker discovery and treatments. Furthermore, the horizon of CCA for the next decade from 2020 onwards is highlighted.

Allyl isothiocyanate treatment alleviates chronic obstructive pulmonary disease through the Nrf2-Notch1 signaling and upregulation of MRP1

AIMS

Chronic obstructive pulmonary disease (COPD) is a disease with high morbidity and mortality worldwide, which can cause serious social and economic burdens. Allyl isothiocyanate (AITC) is one of the most common natural isothiocyanates and has been shown to have anti-inflammatory and antioxidant biological activities. The purpose of this study was to investigate whether AITC regulated Multidrug resistance-associated protein 1 (MRP1), reactive oxide species (ROS) and reduced glutathione (GSH) levels via Nrf2 and Notch1 signaling pathways to treat COPD and whether there was an interaction between these two pathways.

MAIN METHODS

Lung function indexes and histopathological changes in mice were determined by lung function instrument and HE staining, respectively. The protein expression was analyzed using immunohistochemistry and Western blotting. The mRNA expression was measured by RT-PCR in human bronchial epithelial cell line 16HBE. The contents of ROS, GSH and GSSG were detected by kits in 16HBE cells.

KEY FINDINGS

The protein expression of Notch1, Hes1, MRP1, Nrf2, and HO-1 in lung tissues of WT mice and untransfected cells were significantly down-regulated in COPD, then significantly ameliorated in treatment groups. The protein expression of MRP1, Notch1 and Hes1 in lung tissues of Nrf2^-/- mice were markedly reduced. There was a significant reduction in expression of Nrf2, HO-1 and MRP1 in si-Notch1 transfected cells. Pretreatment with AITC markedly improved oxidative stress and GSH-redox disorder in COPD.

SIGNIFICANCE

Our study demonstrates that there is a potential interaction between Nrf2 and Notch1 signaling pathways during treatment of COPD.

Mitogen-Activated Protein Kinases (MAPKs) and Cholangiocarcinoma: The Missing Link

In recent years, the incidence of both liver and biliary tract cancer has increased. Hepatocellular carcinoma (HCC) and cholangiocarcinoma (CCA) are the two most common types of hepatic malignancies. Whereas HCC is the fifth most common malignant tumor in Western countries, the prevalence of CCA has taken an alarming increase from 0.3 to 2.1 cases per 100,000 people. The lack of specific biomarkers makes diagnosis very difficult in the early stages of this fatal cancer. Thus, the prognosis of CCA is dismal and surgery is the only effective treatment, whilst recurrence after resection is common. Even though chemotherapy and radiotherapy may prolong survival in patients with CCA, the 5-year survival rate is still very low-a significant global problem in clinical diagnosis and therapy. The mitogen-activated protein kinase (MAPK) pathway plays an important role in signal transduction by converting extracellular stimuli into a wide range of cellular responses including inflammatory response, stress response, differentiation, survival, and tumorigenesis. Dysregulation of the MAPK cascade involves key signaling components and phosphorylation events that play an important role in tumorigenesis. In this review, we discuss the pathophysiological role of MAPK, current therapeutic options, and the current situation of MAPK-targeted therapies in CCA.

Raddeanin A promotes apoptosis and ameliorates 5-fluorouracil resistance in cholangiocarcinoma cells

BACKGROUND

Bile duct cancer is characterized by fast metastasis and invasion and has been regarded as one of the most aggressive tumors due to the absence of effective diagnosis at an early stage. Therefore, it is in the urgent demand to explore novel diagnostic approaches and therapeutic strategies for bile duct cancer to improve patient survival. Raddeanin A (RA) is extracted from the anemone raddeana regel and has been demonstrated to play antitumor roles in various cancers.

AIM

To investigate the effects of RA treatment on bile duct cancer cells.

METHODS

In this study, four cholangiocarcinoma cell lines (RBE, LIPF155C, LIPF178C, and LICCF) treated with RA were used to test the cell viability. The RA-associated cell functional analysis, 5-fluorouracil (5-Fu) effectiveness as well as cell cycle- and apoptosis-related protein expression were investigated.

RESULTS

RA reduced cell viability in a dose-dependent pattern in four cell lines, and the migration and colony formation abilities were also impaired by RA in RBE and LIPF155C cell lines. RA sensitized cell lines to 5-Fu treatment and enhanced the effects of 5-Fu in cholangiocarcinoma. Also, RA decreased protein expression of Wee1, while the combinational effect of RA and 5-Fu decreased protein expressions of cyclooxygenase-2, B cell lymphoma 2, and Wee1 but increased protein levels of Bax, cyclin D1, and cyclin E.

CONCLUSION

Taken together, the results suggest that RA acts as an anti-cancer agent and enhancer of 5-Fu in bile duct cancer cells via regulating multiple cell cycle and apoptosis-related proteins. This finding provides novel clues to exploring a novel antitumor drug for bile duct cancer.

Molecular Pathogenesis of Cholangiocarcinoma

BACKGROUND

Cholangiocarcinomas are a heterogeneous group of malignancies arising from a number of cells of origin along the biliary tree. Although most cases in Western countries are sporadic, large population-based studies have identified a number of risk factors. This review summarises the evidence behind reported risk factors and current understanding of the molecular pathogenesis of cholangiocarcinoma, with a focus on inflammation and cholestasis as the driving forces in cholangiocarcinoma development.

RISK FACTORS FOR CHOLANGIOCARCINOGENESIS

Cholestatic liver diseases (e.g. primary sclerosing cholangitis and fibropolycystic liver diseases), liver cirrhosis, and biliary stone disease all increase the risk of cholangiocarcinoma. Certain bacterial, viral or parasitic infections such as hepatitis B and C and liver flukes also increase cholangiocarcinoma risk. Other risk factors include inflammatory disorders (such as inflammatory bowel disease and chronic pancreatitis), toxins (e.g. alcohol and tobacco), metabolic conditions (diabetes, obesity and non-alcoholic fatty liver disease) and a number of genetic disorders.

MOLECULAR PATHOGENESIS OF CHOLANGIOCARCINOMA

Regardless of aetiology, most risk factors cause chronic inflammation or cholestasis. Chronic inflammation leads to increased exposure of cholangiocytes to the inflammatory mediators interleukin-6, Tumour Necrosis Factor-ɑ, Cyclo-oxygenase-2 and Wnt, resulting in progressive mutations in tumour suppressor genes, proto-oncogenes and DNA mismatch-repair genes. Accumulating bile acids from cholestasis lead to reduced pH, increased apoptosis and activation of ERK1/2, Akt and NF-κB pathways that encourage cell proliferation, migration and survival. Other mediators upregulated in cholangiocarcinoma include Transforming Growth Factor-β, Vascular Endothelial Growth Factor, Hepatocyte Growth Factor and several microRNAs. Increased expression of the cell surface receptor c-Met, the glucose transporter GLUT-1 and the sodium iodide symporter lead to tumour growth, angiogenesis and cell migration. Stromal changes are also observed, resulting in alterations to the extracellular matrix composition and recruitment of fibroblasts and macrophages that create a microenvironment promoting cell survival, invasion and metastasis.

CONCLUSION

Regardless of aetiology, most risk factors for cholangiocarcinoma cause chronic inflammation and/or cholestasis, leading to the activation of common intracellular pathways that result in reactive cell proliferation, genetic/epigenetic mutations and cholangiocarcinogenesis. An understanding of the molecular pathogenesis of cholangiocarcinoma is vital when developing new diagnostic biomarkers and targeted therapies for this disease.

Notch2 controls hepatocyte-derived cholangiocarcinoma formation in mice

Liver cancer comprises a group of malignant tumors, among which hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma (ICC) are the most common. ICC is especially pernicious and associated with poor clinical outcome. Studies have shown that a subset of human ICCs may originate from mature hepatocytes. However, the mechanisms driving the trans-differentiation of hepatocytes into malignant cholangiocytes remain poorly defined. We adopted lineage tracing techniques and an established murine hepatocyte-derived ICC model by hydrodynamic injection of activated forms of AKT (myr-AKT) and Yap (YapS127A) proto-oncogenes. Wild-type, Notch1 flox/flox , and Notch2 flox/flox mice were used to investigate the role of canonical Notch signaling and Notch receptors in AKT/Yap-driven ICC formation. Human ICC and HCC cell lines were transfected with siRNA against Notch2 to determine whether Notch2 regulates biliary marker expression in liver tumor cells. We found that AKT/Yap-induced ICC formation is hepatocyte derived and this process is strictly dependent on the canonical Notch signaling pathway in vivo. Deletion of Notch2 in AKT/Yap-induced tumors switched the phenotype from ICC to hepatocellular adenoma-like lesions, while inactivation of Notch1 in hepatocytes did not result in significant histomorphological changes. Finally, in vitro studies revealed that Notch2 silencing in ICC and HCC cell lines down-regulates the expression of Sox9 and EpCAM biliary markers. Notch2 is the major determinant of hepatocyte-derived ICC formation in mice.

Molecular Mechanisms Driving Cholangiocarcinoma Invasiveness: An Overview

The acquisition of invasive functions by tumor cells is a first and crucial step toward the development of metastasis, which nowadays represents the main cause of cancer-related death. Cholangiocarcinoma (CCA), a primary liver cancer originating from the biliary epithelium, typically develops intrahepatic or lymph node metastases at early stages, thus preventing the majority of patients from undergoing curative treatments, consistent with their very poor prognosis. As in most carcinomas, CCA cells gradually adopt a motile, mesenchymal-like phenotype, enabling them to cross the basement membrane, detach from the primary tumor, and invade the surrounding stroma. Unfortunately, little is known about the molecular mechanisms that synergistically orchestrate this proinvasive phenotypic switch. Autocrine and paracrine signals (cyto/chemokines, growth factors, and morphogens) permeating the tumor microenvironment undoubtedly play a prominent role in this context. Moreover, a number of recently identified signaling systems are currently drawing attention as putative mechanistic determinants of CCA cell invasion. They encompass transcription factors, protein kinases and phosphatases, ubiquitin ligases, adaptor proteins, and miRNAs, whose aberrant expression may result from either stochastic mutations or the abnormal activation of upstream pro-oncogenic pathways. Herein we sought to summarize the most relevant molecules in this field and to discuss their mechanism of action and potential prognostic relevance in CCA. Hopefully, a deeper knowledge of the molecular determinants of CCA invasiveness will help to identify clinically useful biomarkers and novel druggable targets, with the ultimate goal to develop innovative approaches to the management of this devastating malignancy.

Desmoplastic Tumor Microenvironment and Immunotherapy in Cholangiocarcinoma

Cholangiocarcinoma (CCA) is a dismal disease which often is diagnosed at a late stage where the tumor is locally advanced, metastatic, and, as a result, is associated with low resectability. The heterogeneity of this cancer type is a major reason why the majority of patients fail to respond to therapy, and surgery remains their only curative option. Among patients who undergo surgical intervention, such tumors typically recur in 50% of cases within 1year. Thus, CCA is among the most aggressive and chemoresistant malignancies. CCA is characterized by marked tumor reactive stroma, a fibrogenic connective tissue which surrounds and infiltrates the tumor epithelium. This desmoplastic environment presents a clinical challenge, limiting drug delivery and supporting the growth of the tumor mass. In this review we attempt to highlight key pathways involved in cell to cell communication between the tumor epithelium and stroma, the immune components, and opportunities for novel strategies to improve patient outcome.

The landscape of targeted therapies for cholangiocarcinoma: current status and emerging targets

Cholangiocarcinoma (CCA) is a relatively rare malignancy that arises from the epithelial cells of the intrahepatic, perihilar and distal biliary tree. Intrahepatic CCA (ICC) represents the second most common primary liver cancer, after hepatocellular cancer. Two-thirds of the patients with ICC present with locally advanced or metastatic disease. Despite standard treatment with gemcitabine and cisplatin, prognosis remains dismal with a median survival of less than one year. Several biological plausibilities can account for its poor clinical outcomes. First, despite the advent of next generation and whole exome sequencing, no oncogenic addiction loops have been validated as clinically actionable targets. Second, the anatomical, pathological and molecular heterogeneity, and rarity of CCA confer an ongoing challenge of instituting adequately powered clinical trials. Last, most of the studies were not biomarker-driven, which may undermine the potential benefit of targeted therapy in distinct subpopulations carrying the unique molecular signature. Recent whole genome sequencing efforts have identified known mutations in genes such as epidermal growth factor receptor (EGFR), Kirsten rat sarcoma viral oncogene homolog (KRAS), v-raf murine sarcoma viral oncogene homolog (BRAF) and tumor protein p53 (TP53), novel mutations in isocitrate dehydrogenase (IDH), BRCA1-Associated Protein 1 (BAP1) and AT-rich interactive domain-containing protein 1A (ARID1A), and novel fusions such as fibroblast growth factor receptor 2 (FGFR2) and ROS proto-oncogene 1 (ROS1). In this review, we will discuss the evolving genetic landscape of CCA, with an in depth focus on novel fusions (e.g. FGFR2 and ROS1) and somatic mutations (e.g. IDH1/2), which are promising actionable molecular targets.

Notch1 ablation radiosensitizes glioblastoma cells

Broad specific Notch1 inhibitors suppress glioblastoma multiforme (GBM) growth but have significant gastrointestinal toxicities. Here, we examined Notch1 expression in GBM tissue specimens and its correlation with the overall survival (OS) of GBM patients. Furthermore, using the CRISPR/Cas9 system, we investigated the effects of Notch1 downregulation on clonogenic growth and angiogenesis of GBM cells and xenografts. Immunohistochemistry showed positive Notch1 expression in 71% (49/69) of GBM tissues. Our multivariate Cox regression analysis further revealed that Notch1 expression was an independent adverse prognostic factor for OS. Notch1 downregulation suppressed the growth of GBM cells U87MG and U251. The mean duration to reach 6 x the starting volume was 18.3 days for xenografts with Notch1 downregulation and 13.4 days for the control xenografts. Immunofluorescent staining further disclosed that Notch1 downregulation markedly increased the number of γH2AX foci and radiosensitized GBM cells. Notch1 downregulation also impaired angiogenesis and attenuated VEGF and hypoxic response to irradiation in xenografts. In conclusion, Notch1 ablation inhibited GBM cell proliferation and neovascularization and radiosensitized GBM cells and xenografts, suggesting a pivotal role of Notch1 in tumor growth, angiogenesis, and radioresistance in GBM.

Epithelial-mesenchymal transition in cholangiocarcinoma: From clinical evidence to regulatory networks

Cholangiocarcinoma (CCA) is an aggressive tumor with a poor prognosis due to its late clinical presentation and the lack of effective non-surgical therapies. Unfortunately, most of the patients are not eligible for curative surgery owing to the presence of metastases at the time of diagnosis. Therefore, it is important to understand the steps leading to cell dissemination in patients with CCA. To metastasize from the primary site, cancer cells must acquire migratory and invasive properties by a cell plasticity-promoting phenomenon known as epithelial-mesenchymal transition (EMT). EMT is a reversible dynamic process by which epithelial cells gradually adopt structural and functional characteristics of mesenchymal cells, and has lately become a centre of attention in the field of metastatic dissemination. In the present review, we aim to provide an extensive overview of the current clinical data and the prognostic value of different EMT markers that have been analysed in CCA. We summarize all the regulatory networks implicated in EMT from the membrane receptors to the main EMT-inducing transcription factors (SNAIL, TWIST and ZEB). Furthermore, since a tumor is a complex structure not exclusively formed by tumor cells, we also address the prominent role of the main cell types of the desmoplastic stroma that characterizes CCA in the regulation of EMT. Finally, we discuss the therapeutic considerations and difficulties faced to develop an effective anti-EMT treatment due to the redundancies and bypasses among the pathways regulating EMT.

Autocrine and Paracrine Mechanisms Promoting Chemoresistance in Cholangiocarcinoma

Resistance to conventional chemotherapeutic agents, a typical feature of cholangiocarcinoma, prevents the efficacy of the therapeutic arsenal usually used to combat malignancy in humans. Mechanisms of chemoresistance by neoplastic cholangiocytes include evasion of drug-induced apoptosis mediated by autocrine and paracrine cues released in the tumor microenvironment. Here, recent evidence regarding molecular mechanisms of chemoresistance is reviewed, as well as associations between well-developed chemoresistance and activation of the cancer stem cell compartment. It is concluded that improved understanding of the complex interplay between apoptosis signaling and the promotion of cell survival represent potentially productive areas for active investigation, with the ultimate aim of encouraging future studies to unveil new, effective strategies able to overcome current limitations on treatment.

Jagged 1 is a major Notch ligand along cholangiocarcinoma development in mice and humans

Intrahepatic cholangiocarcinoma (ICC) is a rare yet deadly malignancy with limited treatment options. Activation of the Notch signalling cascade has been implicated in cholangiocarcinogenesis. However, while several studies focused on the Notch receptors required for ICC development, little is known about the upstream inducers responsible for their activation. Here, we show that the Jagged 1 (Jag1) ligand is almost ubiquitously upregulated in human ICC samples when compared with corresponding non-tumorous counterparts. Furthermore, we found that while overexpression of Jag1 alone does not lead to liver tumour development, overexpression of Jag1 synergizes with activated AKT signalling to promote liver carcinogenesis in AKT/Jag1 mice. Histologically, tumours consisted exclusively of ICC, with hepatocellular tumours not occurring in AKT/Jag1 mice. Furthermore, tumours from AKT/Jag1 mice exhibited extensive desmoplastic reaction, an important feature of human ICC. At the molecular level, we found that both AKT/mTOR and Notch cascades are activated in AKT/Jag1 ICC tissues, and that the Notch signalling is necessary for ICC development in AKT/Jag1 mice. In human ICC cell lines, silencing of Jag1 via specific small interfering RNA reduces proliferation and increases apoptosis. Finally, combined inhibition of AKT and Notch pathways is highly detrimental for the in vitro growth of ICC cell lines. In summary, our study demonstrates that Jag1 is an important upstream inducer of the Notch signalling in human and mouse ICC. Targeting Jag1 might represent a novel therapeutic strategy for the treatment of this deadly disease.

Hurdles in selection process of nanodelivery systems for multidrug-resistant cancer

PURPOSE

Most of the nanomedicines for treatment of multidrug-resistant cancer do not reach Phase III trials and many are terminated or withdrawn or are in an indeterminate state since long without any study results being presented. Extensive perusal of nanomedicine development research revealed that one of the critical aspects influencing clinical outcomes and which requires diligent scrutiny is selection process of nanodelivery system.

METHODS

Research papers and articles published on development of nanodelivery systems for treatment of multidrug-resistant cancer were analyzed. Observations and conclusions noted by these researchers which might shed some light on poor clinical performance of nanocarriers were collated and summarized under observation section. Further research articles were studied to find possible solutions which may be applied to these particular problems for resolving them. The inferences of these findings were composed in Result section.

RESULT

Plausible solutions for the observed obstacles were noted as examples of novel formulations that can yield the following: better in vivo imaging, precise targeting and dosing of a specific site and specific cell type in a particular cancer, modulation of tumor surroundings, intonation of systemic effects and high reproducibility.

CONCLUSION

The angle of approach to the development of best nanosystem for a specific type of tumor needs to be spun around. Some of these changes can be brought about by individual scientists, some need to be established by collated efforts of scientists globally and some await advent of better technologies. Regardless of the stratagem, it can be said decisively that the schematics of development phase need rethinking.

Astrocyte-mediated regulation of multidrug resistance p-glycoprotein in fetal and neonatal brain endothelial cells: age-dependent effects

Brain endothelial cells (BECs) form a major component of the blood-brain barrier (BBB). In late gestation, these cells express high levels of the multidrug transporter p-glycoprotein (P-gp; encoded by Abcb1), which prevents the passage of an array of endogenous factors and xenobiotics into the fetal brain. P-gp levels in the BECs increase dramatically in late gestation, coincident with astrocyte differentiation. However, the role of astrocytes in modulating P-gp in the developing BBB is unknown. We hypothesized that factors produced by astrocytes positively regulate P-gp in BECs. Astrocytes and BECs were isolated from fetal and postnatal guinea pigs. Levels of Abcb1 mRNA and P-gp were increased in BECs co-cultured with astrocytes compared to BECs in monoculture. Moreover, postnatal astrocytes enhanced P-gp function in fetal BECs but fetal astrocytes had no effect on postnatal BECs. These effects were dependent on secreted proteins with a molecular weight in the range of 3-100 kDa. LC/MS-MS revealed significant differences in proteins secreted by fetal and postnatal astrocytes. We propose that astrocytes are critical modulators of P-gp at the developing BBB. As such, aberrations in astrocyte maturation, observed in neurodevelopmental disorders, will likely decrease P-gp at the BBB. This would allow increased transfer of P-gp endogenous and exogenous substrates into the brain, many of which have neurodevelopmental consequences.

Risk and Surveillance of Cancers in Primary Biliary Tract Disease

Primary biliary diseases have been associated in several studies with various malignancies. Understanding the risk and optimizing surveillance strategy of these malignancies in this specific subset of patients are an important facet of clinical care. For instance, primary sclerosing cholangitis is associated with an increased risk for cholangiocarcinoma (which is very challenging to diagnose) and when IBD is present for colorectal cancer. On the other hand, primary biliary cirrhosis patients with cirrhosis or not responding to 12 months of ursodeoxycholic acid therapy are at increased risk of hepatocellular carcinoma. In this review we will discuss in detail the risks and optimal surveillance strategies for patients with primary biliary diseases.

Expert consensus document: Cholangiocarcinoma: current knowledge and future perspectives consensus statement from the European Network for the Study of Cholangiocarcinoma (ENS-CCA)

Cholangiocarcinoma (CCA) is a heterogeneous group of malignancies with features of biliary tract differentiation. CCA is the second most common primary liver tumour and the incidence is increasing worldwide. CCA has high mortality owing to its aggressiveness, late diagnosis and refractory nature. In May 2015, the "European Network for the Study of Cholangiocarcinoma" (ENS-CCA: www.enscca.org or www.cholangiocarcinoma.eu) was created to promote and boost international research collaboration on the study of CCA at basic, translational and clinical level. In this Consensus Statement, we aim to provide valuable information on classifications, pathological features, risk factors, cells of origin, genetic and epigenetic modifications and current therapies available for this cancer. Moreover, future directions on basic and clinical investigations and plans for the ENS-CCA are highlighted.

Current diagnosis and treatment of primary intrahepatic cholangiocarcinoma

Primary intrahepatic cholangiocarcinoma (ICC) is a rare malignancy arising from intrahepatic biliary epithelial cells and is also defined as cholangiohepatoma. It is the second most common primary liver malignancy after hepatocellular carcinoma. Epidemiologic research shows that the incidence rate of ICC has increased in recent years. Till now, surgical resection remains the only effective treatment to cure the disease, but single-center large-sample clinical trials are still limited. Early diagnosis of ICC is difficult due to the lack of specific clinical manifestations. The rate of resection is low, while the mortality is high and the prognosis is poor. With the development of medical imaging and pathological diagnosis technology, the early diagnosis and overall survival rates are increasing. Comprehensive therapy including non-surgical treatment plays a more and more important role in improving the prognosis. The aim of this study is to review the advances in the diagnosis and treatment of ICC in recent years.

Identification of Personalized Chemoresistance Genes in Subtypes of Basal-Like Breast Cancer Based on Functional Differences Using Pathway Analysis

Breast cancer is a highly heterogeneous disease that is clinically classified into several subtypes. Among these subtypes, basal-like breast cancer largely overlaps with triple-negative breast cancer (TNBC), and these two groups are generally studied together as a single entity. Differences in the molecular makeup of breast cancers can result in different treatment strategies and prognoses for patients with different breast cancer subtypes. Compared with other subtypes, basal-like and other ER+ breast cancer subtypes exhibit marked differences in etiologic factors, clinical characteristics and therapeutic potential. Anthracycline drugs are typically used as the first-line clinical treatment for basal-like breast cancer subtypes. However, certain patients develop drug resistance following chemotherapy, which can lead to disease relapse and death. Even among patients with basal-like breast cancer, there can be significant molecular differences, and it is difficult to identify specific drug resistance proteins in any given patient using conventional variance testing methods. Therefore, we designed a new method for identifying drug resistance genes. Subgroups, personalized biomarkers, and therapy targets were identified using cluster analysis of differentially expressed genes. We found that basal-like breast cancer could be further divided into at least four distinct subgroups, including two groups at risk for drug resistance and two groups characterized by sensitivity to pharmacotherapy. Based on functional differences among these subgroups, we identified nine biomarkers related to drug resistance: SYK, LCK, GAB2, PAWR, PPARG, MDFI, ZAP70, CIITA and ACTA1. Finally, based on the deviation scores of the examined pathways, 16 pathways were shown to exhibit varying degrees of abnormality in the various subgroups, indicating that patients with different subtypes of basal-like breast cancer can be characterized by differences in the functional status of these pathways. Therefore, these nine differentially expressed genes and their associated functional pathways should provide the basis for novel personalized clinical treatments of basal-like breast cancer.

Overexpression of Notch1 is associated with the progression of cervical cancer

Cervical cancer is the third most common malignancy worldwide, accounting for 250,000 mortalities annually. Notch1, an important regulator of cell-fate decisions and differentiation, has been found to be overexpressed in certain types of cancer. However, the role of Notch1 in cervical carcinogenesis remains unclear. In the present study, immunohistochemical staining and western blot analysis revealed that Notch1 expression was significantly higher in cervical cancer tissues than that in normal cervical tissues. Furthermore, statistical analysis revealed that Notch1 expression was significantly associated with tumor differentiation and tumor stage. These findings indicated that Notch1 expression was associated with the progression of cervical cancer. The western blot assay also identified a positive correlation between Notch1 and Ki67 expression in cervical cancer tissues, which suggested that Notch1 expression may be associated with the proliferation of cervical cancer. In order to further evaluate the specific role of Notch1 in cervical cancer progression, its expression in SiHa and C33A cells was knocked down using small interfering RNA. It was revealed that the knockdown of Notch1 in SiHa and C33A cells resulted in significant inhibition of cell proliferation and colony formation in vitro. These results indicated that Notch1 was able to promote cell proliferation in cervical cancer. In conclusion, the results of the present study indicated that Notch1 may function as a promoter in cervical carcinogenesis.

Curcumin-mediated regulation of Notch1/hairy and enhancer of split-1/survivin: molecular targeting in cholangiocarcinoma

BACKGROUND

Cholangiocarcinoma (CCA) is highly malignant and characterized by poor prognosis with chemotherapeutic resistance. Therefore, continued development of novel, effective approaches are needed. Notch expression is markedly upregulated in CCA, but the utility of Notch1 inhibition is not defined. Based on recent findings, we hypothesized that curcumin, a polyphenolic phytochemical, suppresses CCA growth in vitro via inhibition of Notch1 signaling.

METHODS

Established CCA cell lines CCLP-1 and SG-231 were treated with varying concentrations of curcumin (0-20 μM). Viability was assessed through 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide and clonogenic assays. Evaluation of apoptosis was determined via Western analysis for apoptotic markers and Caspase-Glo 3/7 assay. Cell lysates were further analyzed via Western blotting for Notch1/HES-1/survivin pathway expression, cell cycle progression, and survival.

RESULTS

Curcumin-treated CCA cells exhibited reduced viability compared with control treatment. Statistically significant reductions in cell viability were observed with curcumin treatment at concentrations of 7.5, 10, and 15 μM by approximately 10%, 48%, and 56% for CCLP-1 and 13%, 25%, and 50% for SG-231, respectively. On Western analysis, concentrations of ≥10 μM showed reductions in Notch1, HES-1, and survivin. Apoptosis was evidenced by an increase in expression of cleaved poly [ADP] ribose polymerase and an increase in caspase activity. Cyclin D1 (cell cycle progression) expression levels were also reduced with treatment.

CONCLUSIONS

Curcumin effectively induces CCA (CCLP-1 and SG-231) growth suppression and apoptosis at relatively low treatment concentrations when compared with the previous research. A concomitant reduction of Notch1, HES-1, and survivin expression in CCA cell lines provides novel evidence for a potential antitumorigenic mechanism-of-action. To our knowledge, this is the first report showing reduction in HES-1 expression via protein analysis after treatment with curcumin. Such findings merit further investigation of curcumin-mediated inhibition of Notch signaling in CCA either alone or in combination with chemotherapeutic agents.

Role of liver stem cells in hepatocarcinogenesis

Liver cancer is an aggressive disease with a high mortality rate. Management of liver cancer is strongly dependent on the tumor stage and underlying liver disease. Unfortunately, most cases are discovered when the cancer is already advanced, missing the opportunity for surgical resection. Thus, an improved understanding of the mechanisms responsible for liver cancer initiation and progression will facilitate the detection of more reliable tumor markers and the development of new small molecules for targeted therapy of liver cancer. Recently, there is increasing evidence for the “cancer stem cell hypothesis”, which postulates that liver cancer originates from the malignant transformation of liver stem/progenitor cells (liver cancer stem cells). This cancer stem cell model has important significance for understanding the basic biology of liver cancer and has profound importance for the development of new strategies for cancer prevention and treatment. In this review, we highlight recent advances in the role of liver stem cells in hepatocarcinogenesis. Our review of the literature shows that identification of the cellular origin and the signaling pathways involved is challenging issues in liver cancer with pivotal implications in therapeutic perspectives. Although the dedifferentiation of mature hepatocytes/cholangiocytes in hepatocarcinogenesis cannot be excluded, neoplastic transformation of a stem cell subpopulation more easily explains hepatocarcinogenesis. Elimination of liver cancer stem cells in liver cancer could result in the degeneration of downstream cells, which makes them potential targets for liver cancer therapies. Therefore, liver stem cells could represent a new target for therapeutic approaches to liver cancer in the near future.