Targeting Notch signaling for cancer therapeutic intervention

Signaling pathways in colorectal cancer implications for the target therapies

Colorectal carcinoma (CRC) stands as a pressing global health issue, marked by the unbridled proliferation of immature cells influenced by multifaceted internal and external factors. Numerous studies have explored the intricate mechanisms of tumorigenesis in CRC, with a primary emphasis on signaling pathways, particularly those associated with growth factors and chemokines. However, the sheer diversity of molecular targets introduces complexity into the selection of targeted therapies, posing a significant challenge in achieving treatment precision. The quest for an effective CRC treatment is further complicated by the absence of pathological insights into the mutations or alterations occurring in tumor cells. This study reveals the transfer of signaling from the cell membrane to the nucleus, unveiling recent advancements in this crucial cellular process. By shedding light on this novel dimension, the research enhances our understanding of the molecular intricacies underlying CRC, providing a potential avenue for breakthroughs in targeted therapeutic strategies. In addition, the study comprehensively outlines the potential immune responses incited by the aberrant activation of signaling pathways, with a specific focus on immune cells, cytokines, and their collective impact on the dynamic landscape of drug development. This research not only contributes significantly to advancing CRC treatment and molecular medicine but also lays the groundwork for future breakthroughs and clinical trials, fostering optimism for improved outcomes and refined approaches in combating colorectal carcinoma.

Insights into Melanoma Fibroblast Populations and Therapeutic Strategy Perspectives: Friends or Foes?

Cutaneous melanoma (CM) is an aggressive and highly metastatic solid tumor associated with drug resistance. Before 2011, despite therapies based on cytokines or molecules inhibiting DNA synthesis, metastatic melanoma led to patient death within 18 months from diagnosis. However, recent studies on bidirectional interactions between melanoma cells and tumor microenvironment (TME) have had a significant impact on the development of new therapeutic strategies represented by targeted therapy and immunotherapy. In particular, the heterogeneous stromal fibroblast populations, including fibroblasts, fibroblast aggregates, myofibroblasts, and melanoma associated fibroblasts (MAFs), represent the most abundant cell population of TME and regulate cancer growth differently. Therefore, in this perspective article, we have highlighted the different impacts of fibroblast populations on cancer development and growth. In particular, we focused on the role of MAFs in sustaining melanoma cell survival, proliferation, migration and invasion, drug resistance, and immunoregulation. The important role of constitutively activated MAFs in promoting CM growth and immunoediting makes this cell type a promising target for cancer therapy.

Analyzing the Interaction of RBPJ with Mitotic Chromatin and Its Impact on Transcription Reactivation upon Mitotic Exit

The sequence-specific transcription factor RBPJ, also known as CSL (CBF1, Su(H), Lag1), is an evolutionarily conserved protein that mediates Notch signaling to guide cell fates. When cells enter mitosis, DNA is condensed and most transcription factors dissociate from chromatin; however, a few, select transcription factors, termed bookmarking factors, remain associated. These mitotic chromatin-bound factors are believed to play important roles in maintaining cell fates through cell division. RBPJ is one such factor that remains mitotic chromatin associated and therefore could function as a bookmarking factor. Here, we describe how to obtain highly purified mitotic cells from the mouse embryonal carcinoma cell line F9, perform chromatin immunoprecipitation with mitotic cells, and measure the first run of RNA synthesis upon mitotic exit. These methods serve as basis to understand the roles of mitotic bookmarking by RBPJ in propagating Notch signals through cell division.

The Role of Notch Signaling Pathway in Non-Alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver disease worldwide, and progressive NAFLD can develop into non-alcoholic steatohepatitis (NASH), liver cirrhosis, or hepatocellular carcinoma (HCC). NAFLD is a kind of metabolic disordered disease, which is commonly associated with lipid metabolism, insulin resistance, oxidative stress, inflammation, and fibrogenesis, as well as autophagy. Growing studies have shown Notch signaling pathway plays a pivotal role in the regulation of NAFLD progression. Here, we review the profile of the Notch signaling pathway, new evidence of Notch signaling involvement in NAFLD, and describe the potential of Notch as a biomarker and therapeutic target for NAFLD treatment.

Elucidated tumorigenic role of MAML1 and TWIST1 in gastric cancer is associated with Helicobacter pylori infection

BACKGROUND

Epithelial-mesenchymal transition (EMT) has a fundamental role in tumor initiation, progression, and metastasis. Helicobacter pylori (HP) induces EMT and thus causes gastric cancer (GC) by deregulating multiple signaling pathways involved in EMT. TWIST1 and MAML1 have been confirmed to be critical inducers of EMT via diverse signaling pathways such as Notch signaling. This study aimed to investigate for the first time possible associations between TWIST1/MAML1 mRNA expression levels, HP infection, and clinicopathological characteristics in GC patients.

METHOD

TWIST1 and MAML1 mRNA expression levels were evaluated in tumoral and adjacent normal tissues in 73 GC patients using the quantitative reverse transcription PCR (RT-qPCR) method. PCR technique was also applied to examine the infection with HP in GC samples.

RESULTS

Upregulation of TWIST1 and MAML1 expression was observed in 35 (48%) and 34 (46.6%) of 73 tumor samples, respectively. Co-overexpression of these genes was found in 26 of 73 (35.6%) tumor samples; meanwhile, there was a significant positive correlation between MAML1 and TWIST1 mRNA expression levels (P < 0.001). MAML1 overexpression exhibited meaningful associations with advanced tumor stages (P = 0.006) and nodal metastases (P ˂ 0.001). 34 of 73 (46.6%) tumors tested positive for HP, and meanwhile, MAML1 expression was positively related with T (P = 0.05) and grade (P = 0.0001) in these HP-positive samples. Increased TWIST1 expression was correlated with patient sex (P = 0.035) and advanced tumor grade (P = 0.017) in HP-infected tumors. Furthermore, TWIST1 and MAML1 expression levels were inversely linked with histologic grade in HP-negative tumor samples (P = 0.021 and P = 0.048, respectively).

CONCLUSION

We propose TWIST1 and MAML1 as potential biomarkers of advanced-stage GC that determine the characteristics and aggressiveness of the disease. Based on accumulating evidence and our findings, they can be introduced as promising therapeutic targets to modify functional abnormalities in cells that promote GC progression. Moreover, HP may enhance GC growth and metastasis by disrupting TWIS1/MAML1 expression patterns and related pathways.

Converting melanoma-associated fibroblasts into a tumor-suppressive phenotype by increasing intracellular Notch1 pathway activity

Cancer-associated fibroblasts (CAFs) play a crucial role in cancer progression, drug resistance and tumor recurrence. We have recently shown that the Notch pathway determines the tumor-regulatory role of experimentally created ‘CAFs’. Here, we examined the status of Notch signaling in human melanoma-associated fibroblasts (MAFs) versus their normal counterparts and tested whether manipulation of the Notch pathway activity in MAFs alters their tumor-regulatory function. Using tissue microarrays, we found that MAFs exhibit decreased Notch pathway activity compared with normal fibroblasts in adjacent and non-adjacent skin. Consistently, MAFs isolated from human metastatic melanoma exhibited lower Notch activity than did normal human fibroblasts, demonstrating that Notch pathway activity is low in MAFs. We then investigated the effect of increasing Notch pathway activity in MAF on melanoma growth in co-cultures and in a mouse co-graft model. We found that activation of the Notch pathway in MAFs significantly restricted melanoma cell growth in vitro and suppressed melanoma skin growth and tumor angiogenesis in vivo. Our study demonstrates that the Notch signaling is inhibited in MAFs. Increase of Notch pathway activity can confer tumor-suppressive function on MAFs. Thus, targeting melanoma by activating Notch signaling in MAF may represent a novel therapeutic approach.

More Insights on the Use of γ-Secretase Inhibitors in Cancer Treatment

The NOTCH1 gene encodes a transmembrane receptor protein with activating mutations observed in many T‐cell acute lymphoblastic leukemias (T‐ALLs) and lymphomas, as well as in other tumor types, which has led to interest in inhibiting NOTCH1 signaling as a therapeutic target in cancer. Several classes of Notch inhibitors have been developed, including monoclonal antibodies against NOTCH receptors or ligands, decoys, blocking peptides, and γ‐secretase inhibitors (GSIs). GSIs block a critical proteolytic step in NOTCH activation and are the most widely studied. Current treatments with GSIs have not successfully passed clinical trials because of side effects that limit the maximum tolerable dose. Multiple γ‐secretase–cleavage substrates may be involved in carcinogenesis, indicating that there may be other targets for GSIs. Resistance mechanisms may include PTEN inactivation, mutations involving FBXW7, or constitutive MYC expression conferring independence from NOTCH1 inactivation. Recent studies have suggested that selective targeting γ‐secretase may offer an improved efficacy and toxicity profile over the effects caused by broad‐spectrum GSIs. Understanding the mechanism of GSI‐induced cell death and the ability to accurately identify patients based on the activity of the pathway will improve the response to GSI and support further investigation of such compounds for the rational design of anti‐NOTCH1 therapies for the treatment of T‐ALL.

Implications for Practice

γ‐secretase has been proposed as a therapeutic target in numerous human conditions, including cancer. A better understanding of the structure and function of the γ‐secretase inhibitor (GSI) would help to develop safe and effective γ‐secretase–based therapies. The ability to accurately identify patients based on the activity of the pathway could improve the response to GSI therapy for the treatment of cancer. Toward these ends, this study focused on γ‐secretase inhibitors as a potential therapeutic target for the design of anti‐NOTCH1 therapies for the treatment of T‐cell acute lymphoblastic leukemias and lymphomas.

Understanding the mechanism of γ‐secretase inhibitor (GSI)–induced cell death and the ability to accurately identify patients based on the activity of the pathway could improve the response to GSI therapy for the treatment of cancer. This article focuses on γ‐secretase inhibitors as a potential therapeutic target to treat T‐cell acute lymphoblastic leukemias and lymphomas.

Notch1 signaling determines the plasticity and function of fibroblasts in diabetic wounds

Fibroblasts play a pivotal role in wound healing. However, the molecular mechanisms determining the reparative response of fibroblasts remain unknown. Here, we identify Notch1 signaling as a molecular determinant controlling the plasticity and function of fibroblasts in modulating wound healing and angiogenesis. The Notch pathway is activated in fibroblasts of diabetic wounds but not in normal skin and non-diabetic wounds. Consistently, wound healing in the FSP-1 ^+/- ;ROSA ^LSL-N1IC+/+ mouse, in which Notch1 is activated in fibroblasts, is delayed. Increased Notch1 activity in fibroblasts suppressed their growth, migration, and differentiation into myofibroblasts. Accordingly, significantly fewer myofibroblasts and less collagen were present in granulation tissues of the FSP-1 ^+/- ;ROSA ^LSL-N1IC+/+ mice, demonstrating that high Notch1 activity inhibits fibroblast differentiation. High Notch1 activity in fibroblasts diminished their role in modulating the angiogenic response. We also identified that IL-6 is a functional Notch1 target and involved in regulating angiogenesis. These findings suggest that Notch1 signaling determines the plasticity and function of fibroblasts in wound healing and angiogenesis, unveiling intracellular Notch1 signaling in fibroblasts as potential target for therapeutic intervention in diabetic wound healing.

α-Mangostin-encapsulated PLGA nanoparticles inhibit colorectal cancer growth by inhibiting Notch pathway

Colorectal cancer (CRC) is the fourth leading cause of cancer‐related mortality. Recent studies have stated that Notch signalling is highly activated in cancer stem cells (CSCs) and plays an important role in the development and progression of CRC. Like normal colorectal epithelium, CRCs are organized hierarchically and include populations of CSCs. In order to enhance the biological activity of α‐mangostin, we formulated α‐mangostin‐encapsulated PLGA nanoparticles (Mang‐NPs) and examined the molecular mechanisms by which Mang‐NPs inhibit CRC cell viability, colony formation, epithelial‐mesenchymal transition (EMT) and induce apoptosis. Mang‐NPs inhibited cell viability, colony formation and induced apoptosis. Mang‐NPs also inhibited EMT by up‐regulating E‐cadherin and inhibiting N‐cadherin and transcription factors Snail, Slug and Zeb1. As dysregulated signalling through the Notch receptors promotes oncogenesis, we measured the effects of Mang‐NPs on Notch pathway. Mang‐NPs inhibited Notch signalling by suppressing the expression of Notch receptors (Notch1 and Notch2), their ligands (Jagged 1 and DLL4), γ‐secretase complex protein (Nicastrin) and downstream target (Hes‐1). Notch receptor signalling regulates cell fate determination in stem cell population. Finally, Mang‐NPs inhibited the self‐renewal capacity of CSCs, stem cell markers (CD133, CD44, Musashi and LGR5) and pluripotency maintaining factors (Oct4, Sox‐2, KLF‐4, c‐Myc and Nanog). Overall, our data suggest that Mang‐NPs can inhibit CRC growth, EMT and CSCs’ population by suppressing Notch pathway and its target. Therefore, Mang‐NPs can be used for the treatment and prevention of CRC.

Regulation of GDNF expression in Sertoli cells

Sertoli cells regulate male germ cell proliferation and differentiation and are a critical component of the spermatogonial stem cell (SSC) niche, where homeostasis is maintained by the interplay of several signaling pathways and growth factors. These factors are secreted by Sertoli cells located within the seminiferous epithelium, and by interstitial cells residing between the seminiferous tubules. Sertoli cells and peritubular myoid cells produce glial cell line-derived neurotrophic factor (GDNF), which binds to the RET/GFRA1 receptor complex at the surface of undifferentiated spermatogonia. GDNF is known for its ability to drive SSC self-renewal and proliferation of their direct cell progeny. Even though the effects of GDNF are well studied, our understanding of the regulation its expression is still limited. The purpose of this review is to discuss how GDNF expression in Sertoli cells is modulated within the niche, and how these mechanisms impact germ cell homeostasis.

A Novel Flow Cytometric Assay to Identify Inhibitors of RBPJ-DNA Interactions

Notch signaling is often involved in cancer cell initiation and proliferation. Aberrant Notch activation underlies more than 50% of T-cell acute lymphoblastic leukemia (T-ALL); accordingly, chemicals disrupting Notch signaling are of potential to treat Notch-dependent cancer. Here, we developed a flow cytometry-based high-throughput assay to identify compounds that disrupt the interactions of DNA and RBPJ, the major downstream effector of Notch signaling. From 1492 compounds, we identified 18 compounds that disrupt RBPJ-DNA interactions in a dose-dependent manner. Cell-based assays further revealed that auranofin downregulates Notch-dependent transcription and decreases RBPJ-chromatin interactions in cells. Most strikingly, T-ALL cells that depend on Notch signaling for proliferation are more sensitive to auranofin treatment, supporting the notion that auranofin downregulates Notch signaling by disrupting RBPJ-DNA interaction. These results validate the feasibility of our assay scheme to screen for additional Notch inhibitors and provide a rationale to further test the use of auranofin in treating Notch-dependent cancer.

Therapeutic Targeting of the Notch Pathway in Glioblastoma Multiforme

BACKGROUND

Glioblastoma (GBM) is the most common and deadly form of brain tumor. After standard treatment of resection, radiotherapy, and chemotherapy, the 5-year survival is <5%. In recent years, research has uncovered several potential targets within the Notch signaling pathway, which may lead to improved patient outcomes.

METHODS

A literature search was performed for articles containing the terms "Glioblastoma" and "Receptors, Notch" between 2003 and July 2015. Of the 62 articles retrieved, 46 met our criteria and were included in our review. Nine articles were identified from other sources and were subsequently included, leaving 55 articles reviewed.

RESULTS

Of the 55 articles reviewed, 47 used established human GBM cell lines. Seventeen articles used human GBM surgical samples. Forty-five of 48 articles that assessed Notch activity showed increased expression in GBM cell lines. Targeting the Notch pathway was carried out through Notch knockdown and overexpression and targeting δ-like ligand, Jagged, γ-secretase, ADAM10, ADAM17, and Mastermindlike protein 1. Arsenic trioxide, microRNAs, and several other compounds were shown to have an effect on the Notch pathway in GBM. Notch activity in GBM was also shown to be associated with hypoxia and certain cancer-related molecular pathways such as PI3K/AKT/mTOR and ERK/MAPK. Most articles concluded that Notch activity amplifies malignant characteristics in GBM and targeting this pathway can bring about amelioration of these effects.

CONCLUSIONS

Recent literature suggests targeting the Notch pathway has great potential for future therapies for GBM.

Manipulation of Epithelial Differentiation by HPV Oncoproteins

Papillomaviruses replicate and cause disease in stratified squamous epithelia. Epithelial differentiation is essential for the progression of papillomavirus replication, but differentiation is also impaired by papillomavirus-encoded proteins. The papillomavirus E6 and E7 oncoproteins partially inhibit and/or delay epithelial differentiation and some of the mechanisms by which they do so are beginning to be defined. This review will outline the key features of the relationship between HPV infection and differentiation and will summarize the data indicating that papillomaviruses alter epithelial differentiation. It will describe what is known so far and will highlight open questions about the differentiation-inhibitory mechanisms employed by the papillomaviruses.

Treating the Intestine with Oral ApoA-I Mimetic Tg6F Reduces Tumor Burden in Mouse Models of Metastatic Lung Cancer

Having demonstrated that apolipoprotein A-I (apoA-I) mimetic peptides ameliorate cancer in mouse models, we sought to determine the mechanism for the anti-tumorigenic function of these peptides. CT-26 cells (colon cancer cells that implant and grow into tumors in the lungs) were injected into wild-type BALB/c mice. The day after injection, mice were either continued on chow or switched to chow containing 0.06% of a concentrate of transgenic tomatoes expressing the apoA-I mimetic peptide 6F (Tg6F). After four weeks, the number of lung tumors was significantly lower in Tg6F-fed mice. Gene expression array analyses of jejunum and lung identified Notch pathway genes significantly upregulated, whereas osteopontin (Spp1) was significantly downregulated by Tg6F in both jejunum and lung. In jejunum, Tg6F increased protein levels for Notch1, Notch2, Dll1, and Dll4. In lung, Tg6F increased protein levels for Notch1 and Dll4 and decreased Spp1. Tg6F reduced oxidized phospholipid levels (E06 immunoreactivity) and reduced 25-hydroxycholesterol (25-OHC) levels, which are known to inhibit Notch1 and induce Spp1, respectively. Notch pathway promotes anti-tumorigenic patrolling monocytes, while Spp1 facilitates pro-tumorigenic myeloid derived suppressor cells (MDSCs) formation. Tg6F-fed mice had higher numbers of patrolling monocytes in jejunum and in lung (p < 0.02), and lower plasma levels of Spp1 with reduced numbers of MDSCs in jejunum and in lung (p < 0.03). We conclude that Tg6F alters levels of specific oxidized lipids and 25-OHC to modulate Notch pathways and Spp1, which alter small intestine immune cells, leading to similar changes in lung that reduce tumor burden.

Notch1-WISP-1 axis determines the regulatory role of mesenchymal stem cell-derived stromal fibroblasts in melanoma metastasis

Mesenchymal stem cells-derived fibroblasts (MSC-DF) constitute a significant portion of stromal fibroblasts in the tumor microenvironment (TME) and are key modulators of tumor progression. However, the molecular mechanisms that determine their tumor-regulatory function are poorly understood. Here, we uncover the Notch1 pathway as a molecular determinant that selectively controls the regulatory role of MSC-DF in melanoma metastasis. We demonstrate that the Notch1 pathway's activity is inversely correlated with the metastasis-regulating function of fibroblasts and can determine the metastasis-promoting or -suppressing phenotype of MSC-DF. When co-grafted with melanoma cells, MSC-DFNotch1-/- selectively promote, while MSC-DFN1IC+/+ preferentially suppress melanoma metastasis, but not growth, in mouse models. Consistently, conditioned media (CM) from MSC-DFNotch1-/- and MSC-DFN1IC+/+ oppositely, yet selectively regulates migration, but not growth of melanoma cells in vitro. Additionally, when co-cultured with metastatic melanoma cells in vitro, MSC-DFNotch1-/- support, while MSC-DFN1IC+/+ inhibit melanoma cells in the formation of spheroids. These findings expand the repertoire of Notch1 signaling as a molecular switch in determining the tumor metastasis-regulating function of MSC-DF. We also identified Wnt-induced secreted protein-1 (WISP-1) as a key downstream secretory mediator of Notch1 signaling to execute the influential role of MSC-DF on melanoma metastasis. These findings reveal the Notch1-WISP-1 axis as a crucial molecular determinant in governing stromal regulation of melanoma metastasis; thus, establishing this axis as a potential therapeutic target for melanoma metastasis.

Deletion of Dlk2 increases the vulnerability to anxiety-like behaviors and impairs the anxiolytic action of alprazolam

The purpose of this study was to evaluate the role of the non-canonical DLK2 NOTCH ligand in the regulation of emotional behavior. To this aim, anxiety and depressive-like behaviors were examined in Dlk2 knock-out (Dlk2^-/-) and its corresponding wild-type (WT) mice. Furthermore, relative gene expression analyses of corticotropin releasing hormone (Crh) in the paraventricular nucleus (PVN), glucocorticoid receptor (NR3C1) and FK506 binding protein 5 (FKBP5) in the hippocampus (HIPP), and the transcription factors Hes1, Hes5 and Hey1 in the PVN, HIPP and amygdala (AMY) were carried out in Dlk2^-/- and WT mice under basal conditions and after exposure to restraint stress. The anxiolytic action of alprazolam and the relative gene expression levels of the GABA-A alpha 2 and gamma 2 receptor subunits (Gabra2 and Gabrg2) were also evaluated in the HIPP and AMY of WT and Dlk2^-/- mice. The results reveal that deletion of Dlk2 increased anxiety and depressive-like behaviors and altered the vulnerability to restraint stress on Crh gene expression in the PVN, Nr3c1 and Fkbp5 gene expression in the HIPP, and Hes1, Hes5 and Hey1 gene expression in the PVN, HIPP and AMY. Interestingly, the administration of alprazolam failed to produce an anxiolytic action in Dlk2^-/- mice. Indeed, Gabra2 and Gabrg2 gene expression levels were significantly affected under basal conditions and after stress exposure in Dlk2^-/- mice compared with WT mice. In conclusion, the results suggest that DLK2 plays an important role in the regulation of emotional behaviors and relevant targets of the stress axis, NOTCH pathway and GABAergic neurotransmission. In addition, the deletion of Dlk2 blocked the anxiolytic response to alprazolam. Future studies are needed to determine the relevance of DLK2 as a potential therapeutic target for the treatment of neuropsychiatric disorders with anxiety or depressive-like behaviors.

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.

Sialylated β1, 6 branched N-glycans modulate the adhesion, invasion and metastasis of hepatocarcinoma cells

The mouse hepatocarcinoma cell lines Hca-F and Hca-P have been derived from hepatocarcinoma in mice and metastasize only to the lymph node. Hca-F cells displayed greater lymphatic metastasis ability than Hca-P cells. When the two cell lines were compared for cell surface sialylated β1,6 branched N-glycans by flow cytometry using L-PHA and SNA, Hca-F cells were found to express significantly higher levels. To explore the effect of increased sialylated β1,6 branched N-glycans on hepatocarcinoma progression, we inhibit their expression in Hca-F cells by using swainsonine treatment and RNA interference. We found that swainsonine treatment or GnT-V-shRNA transfection significantly inhibited the formation of β1,6 branched N-glycans, and partially inhibited the expression of α2,6 sialic acids. Knockdown of sialylated β1,6 branched N-glycans significantly attenuated the invasive and metastatic capability both in vitro and in vivo. Blockade of α2,6 sialic acid expression on Hca-F cell surface by the treatment with neuraminidase caused reduction in cellular adherence to lymph node. In addition, knockdown of sialylated β1,6 branched N-glycans could decrease the expression of Notch1, NICD1, NICD2 and HES1 in Hca-F cells. Collectively, these findings suggest that increased sialylated β1,6 branched N-glycans may contribute to hepatocarcinoma progression by altering the adhesive, invasive and metastatic ability to lymph node via Notch signaling pathway.

Expression of p53, p16, cyclin D1, epidermal growth factor receptor and Notch1 in patients with temporal bone squamous cell carcinoma

BACKGROUND

The aim of this study was to investigate the expression of p53, p16, cyclin D1, epidermal growth factor receptor (EGFR) and Notch1 in temporal bone squamous cell carcinoma (TBSCC) tissue samples by immunohistochemistry (IHC), and to evaluate the association between these biomarkers and clinicopathological features.

METHODS

We performed a retrospective, single-institution review of 30 TBSCC patients treated with curative intent between April 2006 and March 2015. All tissue samples were obtained from pretreatment biopsy specimens or surgical specimens and using IHC staining.

RESULTS

Ten patients were categorized as T1, seven as T2, five as T3 and eight as T4. Nine patients had clinically positive lymph node metastasis. The positive expression of p53 and EGFR was significantly associated with T classification (P = 0.042 and P = 0.0039). EGFR expression was significantly more frequent in patients with positive lymph node metastasis compared with patients without node involvement (P = 0.017). In the analysis of the association between protein expression by IHC staining and prognosis, the positive expression of EGFR and Notch1 was significantly correlated with poor survival outcomes in TBSCC (P = 0.015 and P = 0.025) CONCLUSION: Overexpression of p53 and EGFR may be valuable biomarkers for identifying individuals at high risk of developing tumors in TBSCC. Furthermore, the positive expression of EGFR was significantly associated with poor survival outcome. Anti-EGFR therapy has potential for use as the treatment modality of choice for advanced-stage TBSCC as well as other head and neck squamous cell carcinomas.

Hairy/enhancer-of-split related with YRPW motif protein 1 promotes osteosarcoma metastasis via matrix metallopeptidase 9 expression

BACKGROUND

Activation of the Notch pathway has been reported in various types of cancers. However, the role of the hairy/enhancer-of-split related with YRPW motif protein 1 (HEY1) in osteosarcoma is unknown. We examined the function of HEY1 in osteosarcoma.

METHODS

Expression of HEY1 was studied in human osteosarcoma. The effects of HEY1 in osteosarcoma were evaluated in vitro and in a xenograft model. Moreover, we examined the function of matrix metallopeptidase 9 (MMP9) as a downstream effector of HEY1.

RESULTS

HEY1 was upregulated in human osteosarcoma. Knockdown of HEY1 inhibited the invasion of osteosarcoma cell lines. In contrast, the forced expression of HEY1 increased the invasion of mesenchymal stem cell. In addition, lung metastases were significantly inhibited by the knockdown of HEY1. We found that MMP9 was a downstream effector of HEY1 that promotes the invasion of osteosarcoma cells. Knockdown of HEY1 decreased the expression of MMP9. Addition of MMP9 rescued the invasion of osteosarcoma cells that had been rendered less invasive by knockdown of HEY1 expression.

CONCLUSIONS

Our findings suggested that HEY1 augmented the metastasis of osteosarcoma via upregulation of MMP9 expression. Therefore, inhibition of HEY1 may be a novel therapeutic strategy for preventing osteosarcoma metastasis.

A phase II study of single-agent RO4929097, a gamma-secretase inhibitor of Notch signaling, in patients with recurrent platinum-resistant epithelial ovarian cancer: A study of the Princess Margaret, Chicago and California phase II consortia

PURPOSE

A phase II study was performed to evaluate the efficacy and safety of single-agent RO4929097 (a gamma-secretase inhibitor) in patients with recurrent platinum-resistant ovarian cancer.

EXPERIMENTAL DESIGN

Women with progressive platinum-resistant ovarian cancer treated with ≤2 chemotherapy regimens for recurrent disease were enrolled in this trial. Patients received oral RO4929097 at 20 mg once daily, 3 days on/4 days off each week in a three week cycle. The primary endpoint was progression-free survival (PFS) rate at the end of 4 cycles. Secondary objectives included assessment of the safety of RO4929097 and exploration of molecular correlates of outcome in archival tumor tissue and serum.

RESULTS

Of 45 patients enrolled, 40 were evaluable for response. Thirty-seven (82%) patients had high-grade ovarian cancer. No objective responses were observed. Fifteen patients (33%) had stable disease as their best response, with a median duration of 3.1 months. The median PFS for the whole group was 1.3 months (1.2-2.5). Treatment was generally well tolerated with 10% of patients discontinuing treatment due to an adverse event. In high grade serous ovarian cancer patients, the median PFS trended higher when the expression of intracellular Notch (NICD) protein by immunohistochemistry was high versus low (3.3 versus 1.3 months, p=0.09). No clear relationship between circulating angiogenic factors and PFS was found despite a suggestion of an improved outcome with higher baseline VEGFA levels.

CONCLUSIONS

RO4929097 has insufficient activity as a single-agent in platinum-resistant ovarian cancer to warrant further study as monotherapy. Future studies are needed to explore the potential for cohort enrichment using NICD expression.

Monoclonal antibodies against human cancer stem cells

Cancer stem cells (CSCs) are a subpopulation of tumor cells that display self-renewal and tumor initiation capacity and the ability to give rise to the heterogenous lineages of cancer cells that comprise the tumor. CSCs exhibit intrinsic mechanisms of resistance to modern cancer therapeutics, allowing them to survive current cancer therapies and to initiate tumor recurrence and metastasis. Various cell surface and transmembrane proteins expressed by CSCs, including CD44, CD47, CD123, EpCAM (CD326), CD133, IGF receptor I, and proteins of the Notch and Wnt signaling pathways have been identified. Recently, monoclonal antibodies and antibody constructs raised against these CSC proteins have shown efficacy against CSCs in human cancer xenograft mice, and some of them have demonstrated antitumor activity in clinical studies. Since current cancer therapies fail to eliminate CSCs, leading to cancer recurrence and progression, selective targeting of CSCs with monoclonal antibodies and antibody constructs may represent a novel therapeutic strategy against cancer.

Genome-wide microarray expression and genomic alterations by array-CGH analysis in neuroblastoma stem-like cells

Neuroblastoma has a very diverse clinical behaviour: from spontaneous regression to a very aggressive malignant progression and resistance to chemotherapy. This heterogeneous clinical behaviour might be due to the existence of Cancer Stem Cells (CSC), a subpopulation within the tumor with stem-like cell properties: a significant proliferation capacity, a unique self-renewal capacity, and therefore, a higher ability to form new tumors. We enriched the CSC-like cell population content of two commercial neuroblastoma cell lines by the use of conditioned cell culture media for neurospheres, and compared genomic gains and losses and genome expression by array-CGH and microarray analysis, respectively (in CSC-like versus standard tumor cells culture). Despite the array-CGH did not show significant differences between standard and CSC-like in both analyzed cell lines, the microarray expression analysis highlighted some of the most relevant biological processes and molecular functions that might be responsible for the CSC-like phenotype. Some signalling pathways detected seem to be involved in self-renewal of normal tissues (Wnt, Notch, Hh and TGF-β) and contribute to CSC phenotype. We focused on the aberrant activation of TGF-β and Hh signalling pathways, confirming the inhibition of repressors of TGF-β pathway, as SMAD6 and SMAD7 by RT-qPCR. The analysis of the Sonic Hedgehog pathway showed overexpression of PTCH1, GLI1 and SMO. We found overexpression of CD133 and CD15 in SIMA neurospheres, confirming that this cell line was particularly enriched in stem-like cells. This work shows a cross-talk among different pathways in neuroblastoma and its importance in CSC-like cells.

Canonical Notch signalling is inactive in urothelial carcinoma

BACKGROUND

Notch signalling regulates cell fate in most tissues, promoting precursor cell proliferation in some, but differentiation in others. Accordingly, downregulation or overactivity variously contributes to cancer development. So far, little is known about Notch pathway activity and function in the normal urothelium and in urothelial carcinoma (UC). We have therefore investigated expression of Notch pathway components in UC tissues and cell lines and studied the function of one receptor, NOTCH1, in detail.

METHODS

Expression of canonical Notch pathway components were studied in UC and normal bladder tissues by immunohistochemistry and quantitative RT-PCR and in UC cell lines and normal cultured urothelial cells by qRT-PCR, immunocytochemistry and Western blotting. Pathway activity was measured by reporter gene assays. Its influence on cell proliferation was investigated by γ-secretase inhibition. Effects of NOTCH1 restoration were followed by measuring cell cycle distribution, proliferation, clonogenicity and nuclear morphology.

RESULTS

NOTCH1 and its ligand, DLL1, were expressed at plasma membranes and in the cytoplasm of cells in the upper normal urothelium layer, but became downregulated in UC tissues, especially in high-stage tumours. In addition, the proteins were often delocalized intracellularly. According differences were observed in UC cell lines compared to normal urothelial cells. Canonical Notch pathway activity in reporter assays was repressed in UC cell lines compared to normal cells and a mammary carcinoma cell line, but was induced by transfected NOTCH1. Inhibitors of Notch signalling acting at the γ-secretase step did not affect UC cell proliferation at concentrations efficacious against a cell line with known Notch activity. Surprisingly, overexpression of NOTCH1 into UC cell lines did not significantly affect short-term cell proliferation, but induced nuclear abnormalities and diminished clonogenicity.

CONCLUSION

Our data indicate that canonical Notch signalling is suppressed in urothelial carcinoma mainly through downregulation of NOTCH1. These findings can be explained by proposing that canonical Notch signalling may promote differentiation in the urothelium, like in many squamous epithelia, and its suppression may therefore be advantageous for tumour progression. As an important corollary, inhibition of canonical Notch signalling is unlikely to be efficacious and might be counter-productive in the treatment of urothelial carcinoma.

Therapeutic modulation of Notch signalling--are we there yet?

The Notch signalling pathway is evolutionarily conserved and is crucial for the development and homeostasis of most tissues. Deregulated Notch signalling leads to various diseases, such as T cell leukaemia, Alagille syndrome and a stroke and dementia syndrome known as CADASIL, and so strategies to therapeutically modulate Notch signalling are of interest. Clinical trials of Notch pathway inhibitors in patients with solid tumours have been reported, and several approaches are under preclinical evaluation. In this Review, we focus on aspects of the pathway that are amenable to therapeutic intervention, diseases that could be targeted and the various Notch pathway modulation strategies that are currently being explored.

Inhibition of the Jagged/Notch pathway inhibits retinoblastoma cell proliferation via suppressing the PI3K/Akt, Src, p38MAPK and Wnt/β‑catenin signaling pathways

The Notch signaling pathway is a highly conserved developmental pathway, which is important in the regulation of cellular proliferation, differentiation and apoptosis. The aberrant expression of the Notch pathway has been associated with carcinogenesis in various types of cancer. In order to investigate the expression profiles and biological functions of Notch receptors and ligands in retinoblastoma, the expression levels of their proteins in the human retinoblastoma cell line SO‑Rb50 using western blot analysis was assessed. The present study revealed that Notch1 and Jagged2 were highly expressed compared with human retinal pigment epithelial cells. When treated with DAPT, a specific inhibitor of Notch receptor cleavage, expression of Notch1 and Jagged2 were downregulated in a dose‑dependent manner, which was accompanied by substantial cell growth arrest, as indicated by the Cell Counting kit‑8 assay. In addition, phosphorylation of Akt, p38 mitogen‑activated protein kinase and Src, together with the expression of phosphoinositide 3‑kinase and β‑catenin, was abated in a dose‑dependent manner. However, expression of either total extracellular signal‑regulated kinase (Erk)1/2 or phospho‑Erk1/2 was not changed in SO‑Rb50 cells. These findings demonstrated that the Jagged2/Notch1 pathway can promote oncogenesis in retinoblastoma in co‑operation with multiple signaling pathways. The inhibition of the Notch signaling pathway by DAPT represents a potentially attractive strategy for the therapy of retinoblastoma.

Notch1 Overexpression Associates With Poor Prognosis in Human Laryngeal Squamous Cell Carcinoma

Objective:

This study aimed to investigate the expression of Notch1 in human laryngeal squamous cell carcinoma (LSCC) tissues and its relationship to clinicopathologic characteristics as well as their prognostic value in LSCC.

Methods:

Samples from 106 patients with LSCC were analyzed for Notch1 expression by immunohistochemical staining. The relationship between Notch1 expression and clinicopathologic parameters was subsequently analyzed. Univariate analysis and multivariate analysis of patient survival were examined using the Kaplan-Meier method and Cox proportional hazards model, respectively.

Results:

We found that Notch1 had positive expression in 71 of 106 cases of LSCC (66.98%), which was obviously higher than laryngeal normal tissues ( P < .01) and significantly correlated with the clinical stage, lymph node metastasis, and histological grade (all Ps < .05). Univariate analysis revealed that Notch1 expression tended to show an unfavorable influence on overall survival (OS) and disease-free survival (DFS) (both Ps < .01). Multivariate analysis demonstrated that Notch1 was an independent prognostic factor for patients with LSCC ( P < .05).

Conclusion:

These results reveal that Notch1 expression is a potential prognostic factor for malignant progression, metastasis, and survival of LSCC patients. Furthermore, it has been demonstrated that high expression of Notch1 was associated with unfavorable OS and DFS in LSCC patients.

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

The Notch signaling pathway has been reported to play crucial roles in inhibiting hepatocyte differentiation and allowing formation of intrahepatic bile ducts. However, little is known about its significance in intrahepatic cholangiocarcinoma (ICC). The aim of the present study was to investigate the effects of Notch1 expression in ICC tissues and cells. The expression of Notch1 was examined in paraffin-embedded sections of ICC (n=44) by immunohistochemistry. Notch1 was knocked down by RNA interference (RNAi) in cultured ICC cells (RBE and HCCC-9810). The proliferation, invasiveness and sensitivity to 5-fluorouracil (5-FU) were detected by Cell Counting Kit-8 (CCK-8), colony formation assays, Transwell assays and flow cytometry, respectively. The expression levels of several multidrug resistance (MDR)-related genes, MDR1-P-glycoprotein (ABCB‑1), breast cancer resistance protein (ABCG‑2) and the multidrug resistance protein isoform 1 (MRP‑1), were examined by quantitative real-time polymerase chain reaction (qRT-PCR) and western blotting. Notch1 was overexpressed in cell membranes and cytoplasm of ICC compared with the adjacent liver tissue (35/44, 79.5%) and this was more common in cases with tumor size≥5 cm (p=0.021) and HBs-Ag positive (p=0.018). By silencing Notch1, the proliferation and invasiveness of ICC cells were inhibited and the inhibition rate of 5-FU was markedly increased. In addition, IC50 values of 5-FU in RBE cells were decreased from 148.74±0.72 to 5.37±0.28 µg/ml and the corresponding values for HCCC-9810 cells were 326.92±0.87 to 42.60±0.35 µg/ml, respectively. Furthermore, Notch1 silencing clearly increased the percentage of apoptotic cells treated by 5-FU compared with the control. Notch1 knockdown led to diminished expression levels of ABCB‑1 and MRP‑1. Therefore, Notch may play important roles in the development of ICC. Silencing Notch1 can inhibit the proliferation and invasiveness of ICC cells and increase their sensitivity to 5-FU in vitro.

Integrated miRNA-mRNA analysis revealing the potential roles of miRNAs in chordomas

INTRODUCTION

Emerging evidence suggests that microRNAs (miRNAs) are crucially involved in tumorigenesis and that paired expression profiles of miRNAs and mRNAs can be used to identify functional miRNA-target relationships with high precision. However, no studies have applied integrated analysis to miRNA and mRNA profiles in chordomas. The purpose of this study was to provide insights into the pathogenesis of chordomas by using this integrated analysis method.

METHODS

Differentially expressed miRNAs and mRNAs of chordomas (n = 3) and notochord tissues (n = 3) were analyzed by using microarrays with hierarchical clustering analysis. Subsequently, the target genes of the differentially expressed miRNAs were predicted and overlapped with the differentially expressed mRNAs. Then, GO and pathway analyses were performed for the intersecting genes.

RESULTS

The microarray analysis indicated that 33 miRNAs and 2,791 mRNAs were significantly dysregulated between the two groups. Among the 2,791 mRNAs, 911 overlapped with putative miRNA target genes. A pathway analysis showed that the MAPK pathway was consistently enriched in the chordoma tissue and that miR-149-3p, miR-663a, miR-1908, miR-2861 and miR-3185 likely play important roles in the regulation of MAPK pathways. Furthermore, the Notch signaling pathway and the loss of the calcification or ossification capacity of the notochord may also be involved in chordoma pathogenesis.

CONCLUSION

This study provides an integrated dataset of the miRNA and mRNA profiles in chordomas, and the results demonstrate that not only the MAPK pathway and its related miRNAs but also the Notch pathway may be involved in chordoma development. The occurrence of chordoma may be associated with dysfunctional calcification or ossification of the notochord.

Hypoxia, notch signalling, and prostate cancer

The notch signalling pathway is involved in differentiation, proliferation, angiogenesis, vascular remodelling, and apoptosis. Deregulated expression of notch receptors, ligands, and targets is observed in many solid tumours, including prostate cancer. Hypoxia is a common feature of prostate tumours, leading to increased gene instability, reduced treatment response, and increased tumour aggressiveness. The notch signalling pathway is known to regulate vascular cell fate and is responsive to hypoxia-inducible factors. Evidence to date suggests similar, therapeutically exploitable, behaviour of notch-activated and hypoxic prostate cancer cells.

Colon cancer stem cells: Controversies and perspectives

Tumors have long been viewed as a population in which all cells have the equal propensity to form new tumors, the so called conventional stochastic model. The cutting-edge theory on tumor origin and progression, tends to consider cancer as a stem cell disease. Stem cells are actively involved in the onset and maintenance of colon cancer. This review is intended to examine the state of the art on colon cancer stem cells (CSCs), with regard to the recent achievements of basic research and to the corresponding translational consequences. Specific prominence is given to the hypothesized origin of CSCs and to the methods for their identification. The growing understanding of CSC biology is driving the optimization of novel anti-cancer targeted drugs.

Biosensors in clinical practice: focus on oncohematology

Biosensors are devices that are capable of detecting specific biological analytes and converting their presence or concentration into some electrical, thermal, optical or other signal that can be easily analysed. The first biosensor was designed by Clark and Lyons in 1962 as a means of measuring glucose. Since then, much progress has been made and the applications of biosensors are today potentially boundless. This review is limited to their clinical applications, particularly in the field of oncohematology. Biosensors have recently been developed in order to improve the diagnosis and treatment of patients affected by hematological malignancies, such as the biosensor for assessing the in vitro pre-treatment efficacy of cytarabine in acute myeloid leukemia, and the fluorescence resonance energy transfer-based biosensor for assessing the efficacy of imatinib in chronic myeloid leukemia. The review also considers the challenges and future perspectives of biosensors in clinical practice.