Notch-1 induces epithelial-mesenchymal transition consistent with cancer stem cell phenotype in pancreatic cancer cells

Molecular mechanisms underlying the antimetastatic activity of bufalin

Bufalin is a monomer compound extract from Chansu, which is a traditional Chinese medicine obtained from the skin and parotid venom glands of toads, such as Bufo bufo gargarizans Cantor and Bufo melanostictus Schneider. Chansu had been used in traditional Chinese medicine for >1,000 years due to its cardiac, anti-inflammatory and anticancer properties. Previous studies identified bufalin as the main anticancer compound of Chansu, and recent evidence has corroborated its anticancer properties. Bufalin inhibits cancer cell proliferation, induces cell cycle arrest, induces cancer cell apoptosis, inhibits neovascularization, induces cell differentiation, inhibits cancer metastasis and invasion, and enhances chemotherapeutic drug sensitivity. However, the function and mechanism of bufalin in metastatic cancer cells have not yet been expounded. The aim of the present review was to discuss the recent progress and prospects of bufalin in the prevention of cancer metastasis, particularly in inhibiting epithelial-to-mesenchymal transition.

MiR-2861 Behaves as a Biomarker of Lung Cancer Stem Cells and Regulates the HDAC5-ERK System Genes

Cancer stem cells (CSCs) are responsible for cancer initiating, recurrence, and drug resistance. Discovery of novel biomarkers for CSCs is helpful for early diagnosis and prognosis. Lung cancer stem cells (LCSCs) were closely related to the occurrence and development of lung cancer. In our study, the important role of miR-2861 in maintaining the stemness of LCSCs was investigated. The LCSC differentiation model was established through introducing serum into the medium of H460 spheres. miR-2861 expression was significantly higher in LCSCs no matter compared to the differentiation cells or normal cells. HDAC5 expression was positively correlated with miR-2861 in LCSCs, and knockdown of miR-2861 decreased the expression of HDAC5, which implied that HDAC5 may be involved in the differentiation of LCSCs mediated by miR-2861. The role of HDAC5 in the regulation of LCSC differentiation was further verified by the inhibitory effect of LMK-235 on the phosphorylation of ERK1/2, which was recognized as the regulator of CSC differentiation. Our study provided a better understanding of miR-2861 and HDAC5 axis in maintaining the stemness of LCSCs and laid a foundation for molecular targeted therapy.

Effect of midkine on gemcitabine resistance in biliary tract cancer

Gemcitabine-based chemotherapy is one of the most effective and commonly used chemotherapeutic regimens for biliary tract cancer (BTC). However, development of resistance to this drug limits its efficacy. The present study aimed to explore the effects of midkine (MDK) on the resistance of BTC cells to gemcitabine. Cell viability and proliferation were measured by a Cell Counting Kit-8 assay and 5-ethynyl-2′-deoxyuridine staining, respectively. Western blot analysis was used to detect the expression of E-cadherin and vimentin. The results indicated that BTC cell lines were more resistant to gemcitabine plus MDK compared with gemcitabine alone. In terms of the underlying mechanism, MDK promoted the epithelial to mesenchymal transition (EMT) of BTC cells and the enhancing effect of MDK on gemcitabine resistance was abrogated when the EMT was blocked with small interfering (si)RNA targeting Twist. In addition, MDK promoted the expression of Notch-1, while knockdown of Notch-1 by siRNA blocked the EMT process in the BTC cell lines. Taken together, these results indicated that MDK promoted gemcitabine resistance of BTC through inducing EMT via upregulating Notch-1. It was suggested that inhibition of the EMT is a promising strategy to overcome MDK-induced drug resistance.

Targeting Pancreatic Cancer Cell Plasticity: The Latest in Therapeutics

Mortality remains alarmingly high for patients diagnosed with pancreatic ductal adenocarcinoma (PDAC), with 93% succumbing to the disease within five years. The vast majority of PDAC cases are driven by activating mutations in the proto-oncogene KRAS, which results in constitutive proliferation and survival signaling. As efforts to target RAS and its downstream effectors continue, parallel research aimed at identifying novel targets is also needed in order to improve therapeutic options and efficacy. Recent studies demonstrate that self-renewing cancer stem cells (CSCs) contribute to metastatic dissemination and therapy failure, the causes of mortality from PDAC. Here, we discuss current challenges in PDAC therapeutics, highlight the contribution of mesenchymal/CSC plasticity to PDAC pathogenesis, and propose that targeting the drivers of plasticity will prove beneficial. Increasingly, intrinsic oncogenic and extrinsic pro-growth/survival signaling emanating from the tumor microenvironment (TME) are being implicated in the de novo generation of CSC and regulation of tumor cell plasticity. An improved understanding of key regulators of PDAC plasticity is providing new potential avenues for targeting the properties associated with CSC (including enhanced invasion and migration, metastatic outgrowth, and resistance to therapy). Finally, we describe the growing field of therapeutics directed at cancer stem cells and cancer cell plasticity in order to improve the lives of patients with PDAC.

Periarteriolar Glioblastoma Stem Cell Niches Express Bone Marrow Hematopoietic Stem Cell Niche Proteins

In glioblastoma, a fraction of malignant cells consists of therapy-resistant glioblastoma stem cells (GSCs) residing in protective niches that recapitulate hematopoietic stem cell (HSC) niches in bone marrow. We have previously shown that HSC niche proteins stromal cell-derived factor-1α (SDF-1α), C-X-C chemokine receptor type 4 (CXCR4), osteopontin (OPN), and cathepsin K (CatK) are expressed in hypoxic GSC niches around arterioles in five human glioblastoma samples. In HSC niches, HSCs are retained by binding of SDF-1α and OPN to their receptors CXCR4 and CD44, respectively. Protease CatK cleaves SDF-1α to release HSCs out of niches. The aim of the present study was to reproduce the immunohistochemical localization of these GSC markers in 16 human glioblastoma samples with the addition of three novel markers. Furthermore, we assessed the type of blood vessels associated with GSC niches. In total, we found seven GSC niches containing CD133-positive and nestin-positive GSCs as a single-cell layer exclusively around the tunica adventitia of 2% of the CD31-positive and SMA-positive arterioles and not around capillaries and venules. Niches expressed SDF-1α, CXCR4, CatK, OPN, CD44, hypoxia-inducible factor-1α, and vascular endothelial growth factor. In conclusion, we show that GSC niches are present around arterioles and express bone marrow HSC niche proteins.

Crosstalk between the Notch signaling pathway and non-coding RNAs in gastrointestinal cancers

The Notch signaling pathway is one of the main signaling pathways that mediates direct contact between cells, and is essential for normal development. It regulates various cellular processes, including cell proliferation, apoptosis, migration, invasion, angiogenesis and metastasis. It additionally serves an important function in tumor progression. Non-coding RNAs mainly include small microRNAs, long non-coding RNAs and circular RNAs. At present, a large body of literature supports the biological significance of non-coding RNAs in tumor progression. It is also becoming increasingly evident that cross-talk exists between Notch signaling and non-coding RNAs. The present review summarizes the current knowledge of Notch-mediated gastrointestinal cancer cell processes, and the effect of the crosstalk between the three major types of non-coding RNAs and the Notch signaling pathway on the fate of gastrointestinal cancer cells.

The effect of aspirin on circulating tumor cells in metastatic colorectal and breast cancer patients: a phase II trial study

PURPOSE

Aspirin could reduce the risk of cancer metastasis. Circulating tumor cells (CTCs) are a key factor of cancer metastasis, but no evidence has revealed how aspirin affects CTCs and its epithelial-mesenchymal transition (EMT). Here, we conducted a clinical trial to investigate how aspirin affects CTCs in metastatic colorectal cancer (MCC) and breast cancer patients (MBC).

METHODS

The trial is retrospective registered at clinicaltrials.gov (NCT02602938). The eligible patients are given 100 mg aspirin q.d. for 8 weeks, and CTCs are evaluated at baseline, 4 and 8 weeks for absolute number, phenotype (epithelial type, E+, mesenchymal type, M+, and biophenotypic type, B+), and vimentin expression.

RESULTS

Data on 21 MCC and 19 MBC patients are analyzed, and it revealed that the CTC numbers decreased with aspirin treatment in MCC (p < 0.001) but not MBC (p = 0.0532); besides, ratio of E+ CTCs increased (p = 0.037) and M+ CTCs decreased at 2 months in MCC (p = 0.013), but neither the ratio of E+ or M+ CTCs changes significantly in MBC; vimentin expression of M+ CTCs is higher than E+ and B+ CTCs either in MBC or MCC patients at baseline (p < 0.01); and aspirin suppresses the vimentin expression in M+ (p = 0.002)and B+ (p = 0.006) CTCs of MCC and M+ CTCs of MBC (p = 0.004); besides it find vimentin expression in B+ (p = 0.004) or M+ (p < 0.001), CTCs are markedly decreased in patients with total CTC numbers declined.

CONCLUSION

Aspirin could decrease CTCs numbers and block EMT transition in MCC patients and part of MBC patients.

Genistein induces apoptosis of colon cancer cells by reversal of epithelial-to-mesenchymal via a Notch1/NF-κB/slug/E-cadherin pathway

Background

Genistein has been known to inhibit proliferation and induce apoptosis in several kinds of cancer cells. While knowledge of genistein in regulating epithelial mesenchymal transition (EMT) of colon cancer cells is unknown.

Methods

To investigate the effects and mechanisms of genistein on EMT of colon cancer cells, HT-29 cells were used and treated by genistein and TNF-α in this paper. EMT was determined by cell invasion assays using a transwell chamber and the expression changes of EMT-related markers were confirmed by RT–PCR, Western blotting, and immunofluorescence staining.

Results

Genistein inhibited cell migration at 200 μmol/L. Genistein reversed the EMT of colon cancer cells by upregulation of E-cadherin and downregulation of N-cadherin, accompanied by the suppression of EMT related makers, such as Snail2/slug, ZEB1, ZEB2, FOXC1, FOXC2 and TWIST1. Moreover, genistein can inhibit the expression of notch-1, p-NF-κB and NF-κB, while promote the expression of Bax/Bcl-2 and caspase-3 in HT-29 cells.

Conclusion

The present study demonstrated that genistein suppressed the migration of colon cancer cells by reversal the EMT via suppressing the Notch1/NF-κB/slug/E-cadherin pathway. Genistein may be developed as a potential antimetastasis agent to colon cancer.

Interplay between Notch1 and Notch3 promotes EMT and tumor initiation in squamous cell carcinoma

Notch1 transactivates Notch3 to drive terminal differentiation in stratified squamous epithelia. Notch1 and other Notch receptor paralogs cooperate to act as a tumor suppressor in squamous cell carcinomas (SCCs). However, Notch1 can be stochastically activated to promote carcinogenesis in murine models of SCC. Activated form of Notch1 promotes xenograft tumor growth when expressed ectopically. Here, we demonstrate that Notch1 activation and epithelial–mesenchymal transition (EMT) are coupled to promote SCC tumor initiation in concert with transforming growth factor (TGF)-β present in the tumor microenvironment. We find that TGFβ activates the transcription factor ZEB1 to repress Notch3, thereby limiting terminal differentiation. Concurrently, TGFβ drives Notch1-mediated EMT to generate tumor initiating cells characterized by high CD44 expression. Moreover, Notch1 is activated in a small subset of SCC cells at the invasive tumor front and predicts for poor prognosis of esophageal SCC, shedding light upon the tumor promoting oncogenic aspect of Notch1 in SCC.

Notch receptors can exert different roles in cancer. In this manuscript, the authors reveal that Notch1 activation and EMT promote tumor initiation and cancer cell heterogeneity in squamous cell carcinoma, while the repression of Notch3 by ZEB1 limits Notch1-induced differentiation, permitting Notch1-mediated EMT.

Arsenic trioxide inhibits cell growth and motility via up-regulation of let-7a in breast cancer cells

Arsenic trioxide (ATO) has been reported to exert its anti-cancer activities in human cancers. However, the molecular mechanism of ATO-triggered anti-tumor activity has not been fully elucidated. Recently, multiple studies demonstrated that ATO could regulate miRNAs in human cancers. Therefore, in this study, we investigated whether ATO regulated let-7a in breast cancer cells. We found that ATO upregulated let-7a level in breast cancer cells. We also found that up-regulation of let-7a inhibited cell growth and induced apoptosis and retarded cell migration and invasion. We also observed that up-regulation of let-7a enhanced cell growth inhibition and invasion suppression induced by ATO treatment. Our findings suggest that ATO suppressed cell growth, stimulated apoptosis, and retarded cell invasion partly via upregulation of let-7a in breast cancer cells. Our study provides a new anti-tumor mechanism of ATO treatment in breast cancer.

Notch Inhibitors from Calotropis gigantea That Induce Neuronal Differentiation of Neural Stem Cells

Neurodegenerative diseases such as Alzheimer's disease and Parkinson's disease occur due to loss of the structure and function of neurons. For the potential treatment of neurodegenerative diseases, accelerators of neuronal differentiation of neural stem cells (NSCs) have been focused on and a cell-based assay system for measuring Notch signaling pathway activity was constructed. Using this assay system, eight compounds isolated from Calotropis gigantea were identified as inhibitors of the Notch signaling pathway. Hes1 and Hes5 are target genes of the Notch signaling pathway, and compound 1, called uscharin, decreased the protein levels of Hes1 and Hes5 in assay cells and MEB5 cells (mouse NSCs). Furthermore, uscharin (1) enhanced the differentiation of MEB5 cells into neurons. The mechanism of uscharin (1) for the Notch signaling inhibitory activity would be acceleration of the degradation of the Notch intracellular domain (NICD) in the MEB5 cells.

Roles of GSK-3 and microRNAs on epithelial mesenchymal transition and cancer stem cells

Various signaling pathways exert critical roles in the epithelial to mesenchymal transition (EMT) and cancer stem cells (CSCs). The Wnt/beta-catenin, PI3K/PTEN/Akt/mTORC, Ras/Raf/MEK/ERK, hedgehog (Hh), Notch and TP53 pathways elicit essential regulatory influences on cancer initiation, EMT and progression. A common kinase involved in all these pathways is moon-lighting kinase glycogen synthase kinase-3 (GSK-3). These pathways are also regulated by micro-RNAs (miRs). TP53 and components of these pathways can regulate the expression of miRs. Targeting members of these pathways may improve cancer therapy in those malignancies that display their abnormal regulation. This review will discuss the interactions of the multi-functional GSK-3 enzyme in the Wnt/beta-catenin, PI3K/PTEN/Akt/mTORC, Ras/Raf/MEK/ERK, Hh, Notch and TP53 pathways. The regulation of these pathways by miRs and their effects on CSC generation, EMT, invasion and metastasis will be discussed.

Terfenadine combined with epirubicin impedes the chemo-resistant human non-small cell lung cancer both in vitro and in vivo through EMT and Notch reversal

The acquired resistance of non-small cell lung cancer (NSCLC) to taxanes eventually leads to the recurrence and metastasis of tumours. Thus, the development of therapeutic strategies based on the mechanisms by which cells acquire resistance to prolong their survival rate in chemotherapy drug treatment failure patients are warranted. In this study, we found that the resistant cells acquired increased migratory and invasive capabilities, and this transformation was correlated with epithelial-mesenchymal transition (EMT) and Notch pathway deregulation in the resistant cells. Finally, we reported for the first time that terfenadine augmented the effect of epirubicin (EPI) better than Taxol and cisplatin (DDP) by inhibiting migration, invasion, and the EMT phenotype, and the combination therapy also reversed Notch signalling pathway and enhanced the accumulation of fluorescent P-gp substrate rhodamine 123 (Rh123). Similar activities of terfenadine on EPI were observed in xenografts. All of our results confirmed that terfenadine combined with EPI synergistically inhibits the growth and metastatic processes of resistant cells both in vitro and in vivo. Therefore, terfenadine or its derivatives are a promising approach for the clinical challenge of resistance in patients with advanced NSCLC.

Recent progress on the effects of microRNAs and natural products on tumor epithelial-mesenchymal transition

Epithelial–mesenchymal transition (EMT) is a biological process of phenotypic transition of epithelial cells that can promote physiological development as well as tissue healing and repair. In recent years, cancer researchers have noted that EMT is closely related to the occurrence and development of tumors. When tumor cells undergo EMT, they can develop enhanced migration and local tissue invasion abilities, which can lead to metastatic growth. Nevertheless, two researches in NATURE deny its necessity in specific tumors and that is discussed in this review. The degree of EMT and the detection of EMT-associated marker molecules can also be used to judge the risk of metastasis and to evaluate patients’ prognosis. MicroRNAs (miRNAs) are noncoding small RNAs, which can inhibit gene expression and protein translation through specific binding with the 3′ untranslated region of mRNA. In this review, we summarize the miRNAs that are reported to influence EMT through transcription factors such as ZEB, SNAIL, and TWIST, as well as some natural products that regulate EMT in tumors. Moreover, mutual inhibition occurs between some transcription factors and miRNAs, and these effects appear to occur in a complex regulatory network. Thus, understanding the role of miRNAs in EMT and tumor growth may lead to new treatments for malignancies. Natural products can also be combined with conventional chemotherapy to enhance curative effects.

Neoadjuvant treatment for borderline and resectable pancreatic ductal adenocarcinoma

Nowadays and given the improvement in response rate with the new schemes of treatment with chemotherapy, the interest in neoadjuvant treatment for pancreatic ductal adenocarcinoma, allowing the early application of systemic therapies, has also increased. However, treatment selection fundamentally depends on decisions taken by multidisciplinary committees due to the absence of randomized trials on this indication and because the available evidence is based primarily on small studies. The present manuscript tries to establish recommendations based on the available evidence and expert opinion to correctly select the indication, the type of treatment, as well as its duration and how to correctly follow-up patients during treatment with chemotherapy.

Differential expression of the Notch1 receptor, and its ligands Dll1, Dll3 and Dll4 in distinct human pituitary adenoma subtypes

Pituitary adenoma (PA) is a common type of benign tumor of the pituitary gland that is characterized by specific signs and symptoms, primarily associated with hypersecretion of pituitary glycoprotein hormones (thyroid-stimulating, growth and adrenocorticotrophic hormones, and prolactin). Surgery is the first-line treatment, although postoperative residual tissues/cells and subsequent recurrence remain notable complications. Gene therapy is an effective approach for treatment, as previous studies have demonstrated that the Notch signaling pathway participates in the pathogenesis of PA. The focus of the present study was on the associations between the expression of the Notch1 receptor and its ligands δ-like canonical Notch ligand (Dll) 1, Dll3 and Dll4 in patients with PA. Using reverse transcription-quantitative polymerase chain reaction and western blot analyses, to the best of our knowledge, this is the first study to provide a description of the differential expression of the Notch1 receptor and its ligands Dll1, Dll3, and Dll4 in various types of human PA at the mRNA and protein levels. The results of the present study demonstrated that Notch1 protein expression was positively correlated with Dll4 protein expression, but negatively correlated with Dll3 protein expression, indicating synergistic effects between the Notch1 receptor and Dll4 ligand. Furthermore, the Dll3 ligand may be an inhibitor of the Notch1 receptor, indicating an antagonistic association between Notch1 and the Dll3 ligand. These results have identified a potential target for the treatment of patients with PA.

Shifting paradigm of developing biologics for the treatment of pancreatic adenocarcinoma

Pancreatic adenocarcinoma is still widely considered as a deadly disease even though there are substantial therapeutic developments in the past decade. Using combinational chemotherapy regimens, represented by gemcitabine plus nab-paclitaxel and FOLFIRINOX, was able to improve overall survival in patients with advanced disease to a limited extent. It has been a challenge to develop targeted therapies that are focused on the neoplasm cells of pancreatic adenocarcinoma. Recently, targeting the stroma and immune compartments of pancreatic adenocarcinoma has shown promising results. The paradigm of biologics drug development therefore has been shifted by extending to these exciting areas. Although some of the preclinical and clinical researches in targeting the tumor microenvironment of pancreatic adenocarcinoma have shown promising results, others have resulted in controversial findings. Both comprehensive and in-depth researches on the basic science of the tumor microenvironment of pancreatic adenocarcinoma are thus warranted for the development of effective biologics that target the tumor microenvironment. Moreover, an ideal treatment for pancreatic adenocarcinoma shall be a combination of targeting both neoplastic cells and the tumor microenvironment.

Inflammation and Epithelial-Mesenchymal Transition in Pancreatic Ductal Adenocarcinoma: Fighting Against Multiple Opponents

Pancreatic ductal adenocarcinoma (PDAC) is the most common type of pancreatic cancer and one of the most lethal human cancers. Inflammation is a critical component in PDAC initiation and progression. Inflammation also contributes to the aggressiveness of PDAC indirectly via induction of epithelial-mesenchymal transition (EMT), altogether leading to enhanced resistance to chemotherapy and poor survival rates. This review gives an overview of the key pro-inflammatory signaling pathways involved in PDAC pathogenesis and discusses the role of inflammation in induction of EMT and development of chemoresistance in patients with PDAC.

The role of Notch signaling in gastric carcinoma: molecular pathogenesis and novel therapeutic targets

Notch signaling, an evolutionarily conserved signaling cascade system, is involved in promoting the progression of different types of cancers. Within the past decades, the Notch signaling pathway has increasingly been shown to have a primary role in deciding the fate of cancer cells and cancer stem cells in the stomach. Most components of Notch signaling are strongly expressed at different levels in gastric carcinoma tissue samples and are associated with a considerable number of clinical parameters. Moreover, crosstalk signaling between the Notch pathway and the Wnt, Ras, and NF-κB pathways promotes the process of gastric carcinogenesis. Consequently, this increases proliferation and prevents apoptosis in gastric cancer cells, and it contributes to the induction of angiogenesis and accelerates the progression of the epithelial-to-mesenchymal transition. Although the Notch signaling pathway presents novel therapeutic targets for cancer therapeutic intervention, there is still a dearth of in-depth understanding of the molecular mechanisms of Notch signaling in gastric carcinoma. In this review, we summarize the landscape of the Notch signaling pathway and recent findings on Notch signaling in gastric cancer. Furthermore, advanced studies and clinical treatments targeting the Notch signaling pathway arediscussed.

Down-regulation of E-cadherin enhances prostate cancer chemoresistance via Notch signaling

Background

The chemoresistance of prostate cancer (PCa) is invariably associated with the aggressiveness and metastasis of this disease. New emerging evidence indicates that the epithelial-to-mesenchymal transition (EMT) may play pivotal roles in the development of chemoresistance and metastasis. As a hallmark of EMT, E-cadherin is suggested to be a key marker in the development of chemoresistance. However, the molecular mechanisms underlying PCa chemoresistance remain unclear. The current study aimed to explore the association between EMT and chemoresistance in PCa as well as whether changing the expression of E-cadherin would affect PCa chemoresistance.

Methods

Parental PC3 and DU145 cells and their chemoresistant PC3-TxR and DU145-TxR cells were analyzed. PC3-TxR and DU145-TxR cells were transfected with E-cadherin-expressing lentivirus to overexpress E-cadherin; PC3 and DU145 cells were transfected with small interfering RNA to silence E-cadherin. Changes of EMT phenotype-related markers and signaling pathways were assessed by Western blotting and quantitative real-time polymerase chain reaction. Tumor cell migration, invasion, and colony formation were then evaluated by wound healing, transwell, and colony formation assays, respectively. The drug sensitivity was evaluated using MTS assay.

Results

Chemoresistant PC3-TxR and DU145-TxR cells exhibited an invasive and metastatic phenotype that associated with EMT, including the down-regulation of E-cadherin and up-regulation of Vimentin, Snail, and N-cadherin, comparing with that of parental PC3 and DU145 cells. When E-cadherin was overexpressed in PC3-TxR and DU145-TxR cells, the expression of Vimentin and Claudin-1 was down-regulated, and tumor cell migration and invasion were inhibited. In particular, the sensitivity to paclitaxel was reactivated in E-cadherin-overexpressing PC3-TxR and DU145-TxR cells. When E-cadherin expression was silenced in parental PC3 and DU145 cells, the expression of Vimentin and Snail was up-regulated, and, particularly, the sensitivity to paclitaxel was decreased. Interestingly, Notch-1 expression was up-regulated in PC3-TxR and DU145-TxR cells, whereas the E-cadherin expression was down-regulated in these cells comparing with their parental cells. The use of γ-secretase inhibitor, a Notch signaling pathway inhibitor, significantly increased the sensitivity of chemoresistant cells to paclitaxel.

Conclusion

The down-regulation of E-cadherin enhances PCa chemoresistance via Notch signaling, and inhibiting the Notch signaling pathway may reverse PCa chemoresistance.

Role of Notch signaling pathway in pancreatic cancer

Pancreatic cancer (PC) is one of the highly aggressive malignancies in the United States. It has been shown that multiple signaling pathways are involved in the pathogenesis of PC, such as JNK, PI3K/AKT, Rho GTPase, Hedgehog (Hh) and Skp2. In recent years, accumulated evidence has demonstrated that Notch signaling pathway plays critical roles in the development and progression of PC. Therefore, in this review we discuss the recent literature regarding the function and regulation of Notch in the pathogenesis of PC. Moreover, we describe that Notch signaling pathway could be down-regulated by its inhibitors or natural compounds, which could be a novel approach for the treatment of PC patients.

MicroRNA-34a regulates liver regeneration and the development of liver cancer in rats by targeting Notch signaling pathway

OBJECTIVE

This study aimed to investigate the role of microRNA-34a (miR-34a) in regulating liver regeneration (LR) and the development of liver cancer in rats by targeting Notch signaling pathway.

METHODS

Thirty male Sprague-Dawley (SD) rats were randomly assigned into partial hepatectomy (PH) group and sham hepatectomy (SH) group. Hematoxylin and eosin (HE) staining was used to observe the histological change in liver tissues. Enzyme-linked immunosorbent assay (ELISA) was used to measure the serum tumor necrosis factor α (TNF-α) and interleukin-6 (IL-6) levels. Dual-luciferase reporter gene assay was performed to examine whether miR-34a targeted Notch1 gene. Human liver cancer Huh7 cells were transfected and divided into blank, negative control (NC), miR-34a mimics and miR-34a inhibitors groups. MTT and flow cytometry were used to detect cell growth, and cell cycle and apoptosis, respectively. Quantitative real-time polymerase chain reaction (qRT-PCR) was applied detect to the expressions of miR-34a and Notch receptor mRNA. Western blotting was performed to detect the protein expressions of Notch receptors, P21, Bax, Bcl-2 and Bcl-xL. Tumor xenograft in nude mice was done to observe tumor formation in different groups.

RESULTS

Compared to the SH group, miR-34a expression in liver tissues in the PH group decreased first and then increased to the normal level during LR. In early stage of LR, the expressions of Notch receptors and miR-34a were negatively correlated. Compared to the blank and NC groups, the cell growth was inhibited, cell cycle was mainly arrested in the G2/M phase and cell apoptosis rate increased in the miR-34a mimics group. Moreover, the expressions of miR-34a, P21 and Bax were up-regulated, while the expressions of Notch receptors, and Bcl-2 and Bcl-xL were down-regulated in this group. Additionally, the tumor growth in the miR-34a mimics group was reduced. The miR-34a inhibitors group showed contrary tendencies.

CONCLUSION

Our study demonstrates that miR-34a regulated LR and the development of liver cancer by inhibiting Notch signaling pathway.

miR-21 and KLF4 jointly augment epithelial‑mesenchymal transition via the Akt/ERK1/2 pathway

miR-21 induces epithelial-mesenchymal transition (EMT) of human cholangiocarcinoma (CCA) cells. However, the mechanism by which this occurs remains unclear. In the present study, high throughput platform was employed to detect the genes that are differential expressed in QBC939 cells transfected with a hsa-miR-21 antagomir or control vectors. The EMT-related Krüppel-like factor 4 (KLF4) gene was down-regulated after miR-21 was knocked down. Overexpression of miR-21 upregulated KLF4, Akt, ERK and mesenchymal cell markers (N-cadherin and vimentin), downregulated the expression of epithelial cell marker E-cadherin and reduced cell migration and invasion. Immunohistochemistry showed that KLF4, pAkt and pERK were upregulated in tumor xenografts transfected with miR-21 mimics. Inhibitors of the PI3K-Akt and ERK1/2 pathways, LY294002 and U0126, significantly suppressed the EMT phenotype. The present data demonstrated that overexpression of miR-21, accompanied with KLF4, augmented the EMT via inactivation of Akt and ERK1/2 pathways. In conclusion, we have identified a novel mechanism that may be targeted in an attempt to relieve the malignant biological behavior of CCA cells.

PDGF-D promotes cell growth, aggressiveness, angiogenesis and EMT transformation of colorectal cancer by activation of Notch1/Twist1 pathway

Platelet-derived growth factor-D (PDGF-D) plays a crucial role in the progression of several cancers. However, its role in colorectal cancer (CRC) remains unclear. Our study showed that PDGF-D was highly expressed in CRC tissues and was positively associated with the clinicopathological features. Down-regulation of PDGF-D inhibited the tumor growth, migration and angiogenesis of SW480 cells in vitro and in vivo. Whereas up-regulation of PDGF-D promoted the malignant behaviors of HCT116 cells. Moreover, PDGF-D up-regulated the expression of Notch1 and Twist1 in CRC cells. In addition, PDGF-D expression promoted Epithelial to mesenchymal transition (EMT), which was accompanied with decreased E-cadherin and increased Vimentin expression. Consistently, PDGF-D, Notch1, and Twist1 are obviously up-regulated in transforming growth factor-beta 1 (TGF-β1) treated HCT116 cells. Since Notch1 and Twist1 play an important role in EMT and tumor progression, we examined whether there is a correlation between Notch1 and Twist1 in EMT status. Our results showed that up-regulation of Notch1 was able to rescue the effects of PDGF-D down-regulation on Twist1 expression in SW480 cells, whereas down-regulation of Notch1 reduced Twist1 expression in HCT116 cells. Furthermore, we found that Twist1 promoted EMT and aggressiveness of CRC cells. These results suggest that PDGF-D promotes tumor growth and aggressiveness of CRC, moreover, down-regulation of PDGF-D inactivates Notch1/Twist1 axis, which could reverse EMT and prevent CRC progression.

Anti-Cancer Phytometabolites Targeting Cancer Stem Cells

Medicinal plants are a plentiful source of bioactive molecules with much structural diversity. In cancer treatment, molecules obtained from plants represent an attractive alternative to other treatments because several plant-derived compounds have exhibited lower toxicity and higher selectivity against cancer cells. In this review, we focus on the possible application of bioactive molecules obtained from plants against more primitive cell populations in cancers, cancer stem cells. Cancer stem cells are present in several kinds of tumors and are responsible for recurrences and metastases. Common anti-cancer drugs exhibit lower effectiveness against cancer stem cells because of their biological features. However, recently discovered natural phytometabolites exert cytotoxic effects on this rare population of cells in cancers. Therefore, this review presents the latest research on promising compounds from plants that can act as antitumor drugs and that mainly affect stem cell populations in cancers.

microRNA regulation of human pancreatic cancer stem cells

microRNAs (miRNAs) are a group of small non-coding RNAs that function primarily in the post transcriptional regulation of gene expression in plants and animals. Deregulation of miRNA expression in cancer cells, including pancreatic cancer cells, is well documented, and the involvement of miRNAs in orchestrating tumor genesis and cancer progression has been recognized. This review focuses on recent reports demonstrating that miRNAs are involved in regulation of pancreatic cancer stem cells (CSCs). A number of miRNA species have been identified to be involved in regulating pancreatic CSCs, including miR-21, miR-34, miR-1246, miR-221, the miR-17-92 cluster, the miR-200 and let-7 families. Furthermore, the Notch-signaling pathway and epithelial-mesenchymal transition (EMT) process are associated with miRNA regulation of pancreatic CSCs. Given the significant contribution of CSCs to chemo-resistance and tumor progression, a better understanding of how miRNAs function in pancreatic CSCs could provide novel strategies for the development of therapeutics and diagnostics for this devastating disease.

Changes in mitochondrial function during EMT induced by TGFβ-1 in pancreatic cancer

Mitochondrial dysfunction is linked to cancer. Differences in the number, morphology and function of mitochondria have been observed between normal cells and cancer cells. However, changes in mitochondrial function during epithelial-mesenchymal transition (EMT) in pancreatic cancer are less known. In the present study, the cultured human pancreatic cancer cell line Panc-1 was treated with transforming growth factor (TGF)β-1. Mitochondrial functions following TGFβ-1 exposure in pancreatic cancer were investigated. It was noticed that TGFβ-1 treatment induces morphologic changes and a shift from epithelial to mesenchymal phenotype in pancreatic cancer. Furthermore, increased mitochondrial mass was detected in pancreatic cancer following TGFβ-1 treatment. Besides, the production of reactive oxygen species in TGFβ-1-treated pancreatic cancer cells significantly increased compared with the control cells. Our results indicate that the phenomenon of EMT in pancreatic cancer has an association with mitochondrial dysfunction. Mitochondrial dysfunction may be a cause of EMT in pancreatic cancer, which leads to heterogeneity in pancreatic cancer, and may be a potential therapeutic target in the future.

NOTCH receptors in gastric and other gastrointestinal cancers: oncogenes or tumor suppressors?

Gastric cancer (GC) ranks the most common cancer types and is one of the leading causes of cancer-related death. Due to delayed diagnosis and high metastatic frequency, 5-year survival rate of GC is rather low. It is a complex disease resulting from the interaction between environmental factors and host genetic alterations that deregulate multiple signaling pathways. The Notch signaling pathway, a highly conserved system in the regulation of the fate in several cell types, plays a pivotal role in cell differentiation, survival and proliferation. Notch is also one of the most commonly activated signaling pathways in tumors and its aberrant activation plays a key role in cancer advancement. Whether Notch cascade exerts oncogenic or tumor suppressive function in different cancer types depends on the cellular context. Mammals have four NOTCH receptors that modulate Notch pathway activity. In this review, we provide a comprehensive summary on the functional role of NOTCH receptors in gastric and other gastrointestinal cancers. Increasing knowledge of NOTCH receptors in gastrointestinal cancers will help us recognize the underlying mechanisms of Notch signaling and develop novel therapeutic strategies for GC.

Molecular Profiling of Circulating Tumour Cells Identifies Notch1 as a Principal Regulator in Advanced Non-Small Cell Lung Cancer

Knowledge on the molecular mechanisms underlying metastasis colonization in Non-Small Cell Lung Cancer (NSCLC) remains incomplete. A complete overview integrating driver mutations, primary tumour heterogeneity and overt metastasis lacks the dynamic contribution of disseminating metastatic cells due to the inaccessibility to the molecular profiling of Circulating Tumour Cells (CTCs). By combining immunoisolation and whole genome amplification, we performed a global gene expression analysis of EpCAM positive CTCs from advanced NSCLC patients. We identified an EpCAM+ CTC-specific expression profile in NSCLC patients mostly associated with cellular movement, cell adhesion and cell-to-cell signalling mediated by PI3K/AKT, ERK1/2 and NF-kB pathways. NOTCH1 emerged as a driver connecting active signalling pathways, with a reduced number of related candidate genes (NOTCH1, PTP4A3, LGALS3 and ITGB3) being further validated by RT-qPCR on an independent cohort of NSCLC patients. In addition, these markers demonstrated high prognostic value for Progression-Free Survival (PFS). In conclusion, molecular characterization of EpCAM+ CTCs from advanced NSCLC patients provided with highly specific biomarkers with potential applicability as a “liquid biopsy” for monitoring of NSCLC patients and confirmed NOTCH1 as a potential therapeutic target to block lung cancer dissemination.

Notch3 inhibits epithelial-mesenchymal transition by activating Kibra-mediated Hippo/YAP signaling in breast cancer epithelial cells

Invasion, metastasis and chemoresistance are leading causes of death in breast cancer patients. A vital change of epithelial cells, epithelial-mesenchymal transition (EMT), is involved in these processes. Unfortunately, the molecular mechanisms controlling EMT remain to be elucidated. Our previous studies have shown that ectopic N3ICD expression inhibits EMT in MDA-MB-231, a triple-negative breast cancer (TNBC) epithelial cell line. To decipher the mechanism, we performed in-depth studies. Specifically, we found that overexpressing N3ICD transcriptionally upregulated the expression of Kibra, an upstream member of the Hippo pathway. Correspondingly, we also observed that phosphorylated Hippo pathway core kinases, including Lats1/2 and MST1/2, were increased and decreased by overexpressing and knocking down Notch3, respectively. Furthermore, we found that the oncogenic transcriptional coactivator yes-associated protein (YAP), which is negatively regulated by the Hippo pathway, was inhibited by overexpressing N3ICD in breast cancer epithelial cells. The ability of Kibra to inhibit EMT has been previously reported. We thus speculated that Notch3 inhibition of EMT is mediated by upregulated Kibra. To verify this hypothesis, a rescue experiment was performed. Evidently, the ability of Notch3 to inhibit EMT can be countered by knocking down Kibra expression. These data suggest that Notch3 inhibits EMT by activating the Hippo/YAP pathway by upregulating Kibra in breast cancer epithelial cells, and Kibra may be a downstream effector of Notch3. These findings deepen our understanding of EMT in both development and disease, and will undoubtedly help to provide new therapeutic strategies for interfering with cancer invasion and metastasis, especially for TNBC.

Numb/Notch signaling pathway modulation enhances human pancreatic cancer cell radiosensitivity

The present study aims to evaluate whether repression of the Numb/Notch signaling pathway affects the radiosensitivity of human pancreatic cancer cell lines. Different doses of X-rays (0, 2, 3, 4, and 5 Gy) were applied to the PANC-1, SW1990, and MIA PaCa-2 human pancreatic cancer cell lines, and the Numb/Notch pathway inhibitor DAPT was added at different doses (0, 1, 3, and 5 μmol/l). MTT assay, colony formation assay, flow cytometry, scratch assay, and Transwell experiments were performed, and qRT-PCR and Western blot were conducted for the detection of Numb expression. Tumorigenicity assay in nude mice was carried out to verify the influence of blocker of the Numb/Notch signaling pathway on the radiosensitivity of xenograft tumors. The MTT assay, colony formation assay and flow cytometry experiments revealed that proliferation decreased as radiation dose increased. The viability of PANC-1 cells at 5 Gy, SW 1990 cells at 4 Gy and 5 Gy, and MIA PaCa-2 cells at 2-5 Gy was significantly lower than that of non-irradiated cells (all P < 0.05). The migration and invasion assays indicated that the PANC-1 cell line was least radiosensitive, while the MIA PaCa-2 cell line was the most radiosensitive. Numb expression significantly increased with increasing radiation dose, whereas the expression of Hes1, Notch1, and Hes5 significantly decreased compared to non-irradiated cells (P < 0.05). Compared to untreated control cells, DAPT dose dependently increased Numb expression and inhibited Notch1, Hes1, and Hes5 expressions at 2 Gy (P < 0.05). Subcutaneous tumorigenicity assay in nude mice demonstrated that DAPT increased the radiosensitivity of PANC-1, SW 1990, and MIA PaCa-2 cells. These findings suggest that Numb/Notch signaling in pancreatic cancer cells is associated with X-ray radiation and that inhibition of the Numb/Notch signaling pathway can enhance radiosensitivity, suggesting that inhibition of the Numb/Notch signaling pathway may serve as a potential target for clinical improvement of the radiosensitivity of pancreatic cancer.

Cellular Prion Protein Mediates Pancreatic Cancer Cell Survival and Invasion through Association with and Enhanced Signaling of Notch1

Up-regulation of human prion protein (PrP) in patients with pancreatic ductal adenocarcinoma (PDAC) is associated with a poor prognosis. However, the underlying molecular mechanism of PrP-mediated tumorigenesis is not completely understood. In this study, we found that PDAC cell lines can be divided into either PrP high expresser or PrP low expresser. In addition to filamin A (FLNA), PrP interacts with Notch1, forming a PrP/FLNA/Notch1 complex. Silencing PrP in high-expresser cells decreases Notch1 expression and Notch1 signaling. These cells exhibited decreased proliferation, xenograft growth, and tumor invasion but show increased tumor apoptosis. These phenotypes were rescued by ectopically expressed and activated Notch1. By contrast, overexpression of PrP in low expressers increases Notch1 expression and signaling, enhances proliferation, and increases tumor invasion and xenograft growth that can be blocked by a Notch inhibitor. Our data further suggest that PrP increases Notch1 stability likely through suppression of Notch proteosome degradation. Additionally, we found that targeting PrP combined with anti-Notch is much more effective than singularly targeted therapy in retarding PDAC growth. Finally, we show that coexpression of PrP and Notch1 confers an even poorer prognosis than PrP expression alone. Taken together, our results have unraveled a novel molecular pathway driven by interactions between PrP and Notch1 in the progression of PDAC, supporting a critical tumor-promoting role of Notch1 in PrP-expressing PDAC tumors.

Racial disparity in colorectal cancer: Gut microbiome and cancer stem cells

Over the past two decades there has been remarkable progress in cancer diagnosis, treatment and screening. The basic mechanisms leading to pathogenesis of various types of cancers are also understood better and some patients, if diagnosed at a particular stage go on to lead a normal pre-diagnosis life. Despite these achievements, racial disparity in some cancers remains a mystery. The higher incidence, aggressiveness and mortality of breast, prostate and colorectal cancers (CRCs) in African-Americans as compared to Caucasian-Americans are now well documented. The polyp-carcinoma sequence in CRC and easy access to colonic epithelia or colonic epithelial cells through colonoscopy/colonic effluent provides the opportunity to study colonic stem cells early in course of natural history of the disease. With the advent of metagenomic sequencing, uncultivable organisms can now be identified in stool and their numbers correlated with the effects on colonic epithelia. It would be expected that these techniques would revolutionize our understanding of the racial disparity in CRC and pave a way for the same in other cancers as well. Unfortunately, this has not happened. Our understanding of the underlying factors responsible in African-Americans for higher incidence and mortality from colorectal carcinoma remains minimal. In this review, we aim to summarize the available data on role of microbiome and cancer stem cells in racial disparity in CRC. This will provide a platform for further research on this topic.

Cellular Prion Protein Mediates Pancreatic Cancer Cell Survival and Invasion through Association with and Enhanced Signaling of Notch1

Up-regulation of human prion protein (PrP) in patients with pancreatic ductal adenocarcinoma (PDAC) is associated with a poor prognosis. However, the underlying molecular mechanism of PrP-mediated tumorigenesis is not completely understood. In this study, we found that PDAC cell lines can be divided into either PrP high expresser or PrP low expresser. In addition to filamin A (FLNA), PrP interacts with Notch1, forming a PrP/FLNA/Notch1 complex. Silencing PrP in high-expresser cells decreases Notch1 expression and Notch1 signaling. These cells exhibited decreased proliferation, xenograft growth, and tumor invasion but show increased tumor apoptosis. These phenotypes were rescued by ectopically expressed and activated Notch1. By contrast, overexpression of PrP in low expressers increases Notch1 expression and signaling, enhances proliferation, and increases tumor invasion and xenograft growth that can be blocked by a Notch inhibitor. Our data further suggest that PrP increases Notch1 stability likely through suppression of Notch proteosome degradation. Additionally, we found that targeting PrP combined with anti-Notch is much more effective than singularly targeted therapy in retarding PDAC growth. Finally, we show that coexpression of PrP and Notch1 confers an even poorer prognosis than PrP expression alone. Taken together, our results have unraveled a novel molecular pathway driven by interactions between PrP and Notch1 in the progression of PDAC, supporting a critical tumor-promoting role of Notch1 in PrP-expressing PDAC tumors.

The Role of Notch1 Signaling in Anaplastic Thyroid Carcinoma

PURPOSE

The Notch signaling pathway is widely expressed in normal, reactive, and neoplastic tissues; however, its role in thyroid tissues has not been fully elucidated. Therefore, this study was conducted to characterize the expression of the Notch signaling pathway in papillary thyroid cancer (PTC) cells and anaplastic thyroid cancer (ATC) cells.

MATERIALS AND METHODS

Expression of activated Notch1 in ATC and PTC paraffin-embedded tissues was determined by immunohistochemistry. The small interfering RNA techniquewas employed to knock down Notch1 expression in ATC and PTC cell lines.

RESULTS

The expression of activated Notch1 was higher in ATC cases than in PTC cases. Inhibition of Notch1 significantly reduced proliferation and migration of ATC cells, but not PTC cells. In addition, inhibition of Notch1 in ATC cells significantly reduced the expression of key markers of epithelial-mesenchymal transition and cancer stem cells. Conversely, changes in the expression of these proteins were not observed in PTC cells.

CONCLUSION

The results of this study suggest that Notch1 expression plays different roles in tumor progression in ATC and PTC cells. We also found that Notch1 expression was significantly related to the highly invasive or proliferative activity of ATC cells.

Pancreatic cancer stem cell markers and exosomes - the incentive push

Pancreatic cancer (PaCa) has the highest death rate and incidence is increasing. Poor prognosis is due to late diagnosis and early metastatic spread, which is ascribed to a minor population of so called cancer stem cells (CSC) within the mass of the primary tumor. CSC are defined by biological features, which they share with adult stem cells like longevity, rare cell division, the capacity for self renewal, differentiation, drug resistance and the requirement for a niche. CSC can also be identified by sets of markers, which for pancreatic CSC (Pa-CSC) include CD44v6, c-Met, Tspan8, alpha6beta4, CXCR4, CD133, EpCAM and claudin7. The functional relevance of CSC markers is still disputed. We hypothesize that Pa-CSC markers play a decisive role in tumor progression. This is fostered by the location in glycolipid-enriched membrane domains, which function as signaling platform and support connectivity of the individual Pa-CSC markers. Outside-in signaling supports apoptosis resistance, stem cell gene expression and tumor suppressor gene repression as well as miRNA transcription and silencing. Pa-CSC markers also contribute to motility and invasiveness. By ligand binding host cells are triggered towards creating a milieu supporting Pa-CSC maintenance. Furthermore, CSC markers contribute to the generation, loading and delivery of exosomes, whereby CSC gain the capacity for a cell-cell contact independent crosstalk with the host and neighboring non-CSC. This allows Pa-CSC exosomes (TEX) to reprogram neighboring non-CSC towards epithelial mesenchymal transition and to stimulate host cells towards preparing a niche for metastasizing tumor cells. Finally, TEX communicate with the matrix to support tumor cell motility, invasion and homing. We will discuss the possibility that CSC markers are the initial trigger for these processes and what is the special contribution of CSC-TEX.

Cancer of the Pancreas: Molecular Pathways and Current Advancement in Treatment

Pancreatic cancer is one of the most lethal cancers among all malignances, with a median overall survival of <1 year and a 5-year survival of ~5%. The dismal survival rate and prognosis are likely due to lack of early diagnosis, fulminant disease course, high metastasis rate, and disappointing treatment outcome. Pancreatic cancers harbor a variety of genetic alternations that render it difficult to treat even with targeted therapy. Recent studies revealed that pancreatic cancers are highly enriched with a cancer stem cell (CSC) population, which is resistant to chemotherapeutic drugs, and therefore escapes chemotherapy and promotes tumor recurrence. Cancer cell epithelial to mesenchymal transition (EMT) is highly associated with metastasis, generation of CSCs, and treatment resistance in pancreatic cancer. Reviewed here are the molecular biology of pancreatic cancer, the major signaling pathways regulating pancreatic cancer EMT and CSCs, and the advancement in current clinical and experimental treatments for pancreatic cancer.

3,6-dihydroxyflavone suppresses the epithelial-mesenchymal transition in breast cancer cells by inhibiting the Notch signaling pathway

The epithelial to mesenchymal transition (EMT) is a critical developmental program in cancer stem cell (CSC) maintenance and in cancer metastasis. Here, our study found that 3,6-DHF could effectively inhibit EMT in BC cells in vitro and in vivo. 3,6-DHF effectively inhibits the formation and proliferation of BCSCs, and consequently reduces the tumor-initiating capacity of tumor cells in NOD/SCID mice. Optical in vivo imaging of cancer metastasis showed that 3,6-DHF administration suppresses the lung metastasis of BC cells in vivo. Further studies indicated that 3,6-DHF down-regulates Notch1, NICD, Hes-1 and c-Myc, consequently decreasing the formation of the functional transcriptional unit of NICD-CSL-MAML, causing Notch signaling inactivation in BC cells. Over-expression of Notch1 or inhibition of miR-34a significantly reduced the inhibitory effects of 3,6-DHF on EMT, CSCs, as well as cells migration and invasion in BC cells. These data indicated that 3,6-DHF effectively inhibits EMT and CSCs, as well as cells migration and invasion in BC cells, in which miR-34a-mediated Notch1 down-regulation plays a crucial role.

High-Throughput Single-Cell Derived Sphere Formation for Cancer Stem-Like Cell Identification and Analysis

Considerable evidence suggests that many malignancies are driven by a cellular compartment that displays stem cell properties. Cancer stem-like cells (CSCs) can be identified by expression of cell surface markers or enzymatic activity, but these methods are limited by phenotypic heterogeneity and plasticity of CSCs. An alternative phenotypic methodology based on in-vitro sphere formation has been developed, but it is typically labor-intensive and low-throughput. In this work, we present a 1,024-microchamber microfluidic platform for single-cell derived sphere formation. Utilizing a hydrodynamic capturing scheme, more than 70% of the microchambers capture only one cell, allowing for monitoring of sphere formation from heterogeneous cancer cell populations for identification of CSCs. Single-cell derived spheres can be retrieved and dissociated for single-cell analysis using a custom 96-gene panel to probe heterogeneity within the clonal CSC spheres. This microfluidic platform provides reliable and high-throughput sphere formation for CSC identification and downstream clonal analysis.

Roles of Dietary Phytoestrogens on the Regulation of Epithelial-Mesenchymal Transition in Diverse Cancer Metastasis

Epithelial-mesenchymal transition (EMT) plays a key role in tumor progression. The cells undergoing EMT upregulate the expression of cell motility-related proteins and show enhanced migration and invasion. The hallmarks of EMT in cancer cells include changed cell morphology and increased metastatic capabilities in cell migration and invasion. Therefore, prevention of EMT is an important tool for the inhibition of tumor metastasis. A novel preventive therapy is needed, such as treatment of natural dietary substances that are nontoxic to normal human cells, but effective in inhibiting cancer cells. Phytoestrogens, such as genistein, resveratrol, kaempferol and 3,3′-diindolylmethane (DIM), can be raised as possible candidates. They are plant-derived dietary estrogens, which are found in tea, vegetables and fruits, and are known to have various biological efficacies, including chemopreventive activity against cancers. Specifically, these phytoestrogens may induce not only anti-proliferation, apoptosis and cell cycle arrest, but also anti-metastasis by inhibiting the EMT process in various cancer cells. There have been several signaling pathways found to be associated with the induction of the EMT process in cancer cells. Phytoestrogens were demonstrated to have chemopreventive effects on cancer metastasis by inhibiting EMT-associated pathways, such as Notch-1 and TGF-beta signaling. As a result, phytoestrogens can inhibit or reverse the EMT process by upregulating the expression of epithelial phenotypes, including E-cadherin, and downregulating the expression of mesenchymal phenotypes, including N-cadherin, Snail, Slug, and vimentin. In this review, we focused on the important roles of phytoestrogens in inhibiting EMT in many types of cancer and suggested phytoestrogens as prominent alternative compounds to chemotherapy.

Metastasis: new functional implications of platelets and megakaryocytes

Platelets are essential components of hemostasis. Due to a plethora of factors released on activation, platelet functions are also connected to tumor growth, notably by acting on angiogenesis. It is now well recognized that major roles of platelets in the poor outcome of cancer patients occurs during hematogenous dissemination of cancer cells. In this review, we describe recent insights into the molecular mechanisms supporting the prometastatic activity of platelets. Platelets have been shown to promote survival of circulating tumor cells (CTCs) in the bloodstream by conferring resistance to the shear stress and attack from natural killer cells. Recently, platelets were found to promote and/or maintain the state of epithelial to mesenchymal transition on CTCs through platelet secretion of transforming growth factor β in response to CTC activation. At a later stage in the metastatic process, platelets promote extravasation and establishment of metastatic cells in distant organs as observed in bone. This particular environment is also the site of hematopoiesis, megakaryocytopoiesis, and platelet production. Increasing the number of megakaryocytes (MKs) in the bone marrow results in a high bone mass phenotype and inhibits skeletal metastasis formation of prostate cancer cells. As a result of their specific location in vascular niches in the bone marrow, MK activity might contribute to the "seed and soil" suitability between CTCs and bone. In conclusion, recent findings have made a great advance in our knowledge on how platelets contribute to the metastatic dissemination of cancer cells and that may support the development of new antimetastasis therapies.

NOTCH1 inhibition enhances the efficacy of conventional chemotherapeutic agents by targeting head neck cancer stem cell

Cancer stem cells (CSCs) are considered responsible for tumor initiation and chemoresistance. This study was aimed to investigate the possibility of targeting head neck squamous cell carcinoma (HNSCC) by NOTCH1 pathway inhibition and explore the synergistic effect of combining NOTCH inhibition with conventional chemotherapy. NOTCH1/HES1 elevation was found in human HNSCC, especially in tissue post chemotherapy and lymph node metastasis, which is correlated with CSCs markers. NOTCH1 inhibitor DAPT (GSI-IX) significantly reduces CSCs population and tumor self-renewal ability in vitro and in vivo. Flow cytometry analysis showed that NOTCH1 inhibition reduces CSCs frequency either alone or in combination with chemotherapeutic agents, namely, cisplatin, docetaxel, and 5-fluorouracil. The combined strategy of NOTCH1 blockade and chemotherapy synergistically attenuated chemotherapy-enriched CSC population, promising a potential therapeutic exploitation in future clinical trial.

miR-200c: a versatile watchdog in cancer progression, EMT, and drug resistance

MicroRNAs (miRNAs) are 20-22-nucleotide small endogenous non-coding RNAs which regulate gene expression at post-transcriptional level. In the last two decades, identification of almost 2600 miRNAs in human and their potential to be modulated opened a new avenue to target almost all hallmarks of cancer. miRNAs have been classified as tumor suppressors or oncogenes depending on the phenotype they induce, the targets they modulate, and the tissue where they function. miR-200c, an illustrious tumor suppressor, is one of the highly studied miRNAs in terms of development, stemness, proliferation, epithelial-mesenchymal transition (EMT), therapy resistance, and metastasis. In this review, we first focus on the regulation of miR-200c expression and its role in regulating EMT in a ZEB1/E-cadherin axis-dependent and ZEB1/E-cadherin axis-independent manner. We then describe the role of miR-200c in therapy resistance in terms of multidrug resistance, chemoresistance, targeted therapy resistance, and radiotherapy resistance in various cancer types. We highlight the importance of miR-200c at the intersection of EMT and chemoresistance. Furthermore, we show how miR-200c coordinates several important signaling cascades such as TGF-β signaling, PI3K/Akt signaling, Notch signaling, VEGF signaling, and NF-κB signaling. Finally, we discuss miR-200c as a potential prognostic/diagnostic biomarker in several diseases, but mainly focusing on cancer and its potential application in future therapeutics.