Notch1 is an effector of Akt and hypoxia in melanoma development

Notch signaling regulates Th17 cells differentiation through PI3K/AKT/mTORC1 pathway and involves in the thyroid injury of autoimmune thyroiditis

PURPOSE

Autoimmune Thyroiditis (AIT) is the most common thyroid disease; however, there were no measures to prevent the progression of the disease. The present study attempts to identify that Notch signaling regulates the differentiation of T helper 17 (Th17) cells by activating downstream Phosphatidylinositol-3 kinase/protein kinase/mechanistic target of rapamycin complex 1 (PI3K/AKT/mTORC1) pathway participating in the thyroid injury of the experimental autoimmune thyroiditis (EAT).

METHODS

In vivo experiments, mice were randomly divided into 4 groups: a control group, an EAT group, and two groups with LY294002 treatment (pTg plus 25 mg/kg or 50 mg/kg LY294002, respectively). The degrees of thyroiditis were evaluated, and the percentage of Th17 cells, expression of interleukin-17A (IL-17A), and the main components of the Notch-PI3K signaling pathway were detected in different groups. In vitro experiments, two different dosages of LY294002 (25 and 50 μM) were used to intervene splenic mononuclear cells (SMCs) from EAT mice to further evaluate the regulatory effect of Notch-PI3K pathway on Th17 cells.

RESULTS

Our data demonstrate that the infiltration of Th17 cells and the expressions of IL-17A, Notch, hairy and split 1 (Hes1), p‑AKT (Ser473), p‑AKT (Thr308), p‑mTOR (Ser2448), S6K1, and S6K2 increased remarkably in EAT mice. After PI3K pathway was blocked, the degrees of thyroiditis were significantly alleviated, and the proportion of Th17 cells, the expression of IL-17A, and the above Notch-PI3K pathway-related molecules decreased in a dose-dependent manner. Additionally, the proportion of Th17 cells was positively correlated with the concentration of serum thyroglobulin antibody (TgAb), IL-17A, and Notch-PI3K pathway-related molecules mRNA levels.

CONCLUSIONS

Notch signal promotes the secretion of IL-17A from Th17 cells by regulating the downstream PI3K/AKT/mTORC1 pathway through Hes-Phosphatase and tensin homolog (PTEN) and participates in thyroid autoimmune damage, and the PI3K pathway inhibitor may play important effects on AIT by affecting Th17 cells differentiation.

Nano-Gels: Recent Advancement in Fabrication Methods for Mitigation of Skin Cancer

In the 21st century, melanoma and non-melanoma skin cancers have become an epidemic outbreak worldwide. Therefore, the exploration of all potential preventative and therapeutic measures based on either physical or bio-chemical mechanisms is essential via understanding precise pathophysiological pathways (Mitogen-activated protein kinase, Phosphatidylinositol 3-kinase Pathway, and Notch signaling pathway) and other aspects of such skin malignancies. Nano-gel, a three-dimensional polymeric cross-linked porous hydrogel having a diameter of 20-200 nm, possesses dual properties of both hydrogel and nanoparticle. The capacity of high drug entrapment efficiency with greater thermodynamic stability, remarkable solubilization potential, and swelling behavior of nano-gel becomes a promising candidate as a targeted drug delivery system in the treatment of skin cancer. Nano-gel can be either synthetically or architectonically modified for responding to either internal or external stimuli, including radiation, ultrasound, enzyme, magnetic, pH, temperature, and oxidation-reduction to achieve controlled release of pharmaceuticals and several bio-active molecules such as proteins, peptides, genes via amplifying drug aggregation in the active targeted tissue and reducing adverse pharmacological effects. Several drugs, such as anti-neoplastic biomolecules having short biological half-lives and prompt enzyme degradability capacity, must be appropriate for administration employing either chemically bridged or physically constructed nano-gel frameworks. The comprehensive review summarizes the advancement in the preparation and characterization methods of targeted nano-gel with enhanced pharmacological potential and preserved intracellular safety limits for the mitigation of skin malignancies with a special emphasize on skin cancer inducing pathophysiological pathways and prospective research opportunities for skin malignancy targeted nano-gels.

Sodium Nitroprusside Stimulation of Elastic Matrix Regeneration by Aneurysmal Smooth Muscle Cells

The chronic overexpression of matrix metalloproteases leading to consequent degradation and loss of the elastic matrix with the reduction in tissue elasticity is central to the pathophysiology of proteolytic disorders, such as abdominal aortic aneurysms (AAAs), which are localized rupture-prone aortic expansions. Effecting tissue repair to alleviate this condition is contingent on restoring elastic matrix homeostasis in the aortic wall. This is naturally irreversible due to the poor elastogenicity of adult and diseased vascular cells, and the impaired ability to assemble mature elastic fibers, more so in the context of phenotypic changes to medial smooth muscle cells (SMCs) owing to the loss of nitric oxide (NO) signaling in the AAA wall tissue. In this study, we report the benefits of the exposure of primary human aneurysmal SMCs (aHASMCs) to NO donor drug, sodium nitroprusside (SNP), in improving extracellular matrix homeostasis, particularly aspects of elastic fiber assembly, and inhibition of proteolytic degradation. SNP treatment (100 nM) upregulated elastic matrix regeneration at both gene (p < 0.05) and protein levels (p < 0.01) without affecting cell proliferation, improved gene, and protein expression of crosslinking enzyme, lysyl oxidase (p < 0.05), inhibited the expression of MMP2 (matrix metalloprotease 2) significantly (p < 0.05) and promoted contractile SMC phenotypes in aHASMC culture. In addition, SNP also attenuated the expression of mitogen-activated protein kinases, a significant player in AAA formation and progression. Our results indicate the promise of SNP for therapeutic augmentation of elastic matrix regeneration, with prospects for wall repair in AAAs. Impact Statement Chronic and naturally irreversible enzymatic degradation and loss of elastic fibers are centric to proteolytic disorders such as abdominal aortic aneurysms (AAAs). This is linked to poor elastogenicity of adult and diseased vascular cells, compromising their ability to assemble mature elastic fibers. Toward addressing this, we demonstrate the phenotype-modulatory properties of a nitric oxide donor drug, sodium nitroprusside on aneurysmal smooth muscle cells, and its dose-specific proelastogenic and antiproteolytic properties for restoring elastic matrix homeostasis. Combined with the development of vehicles for site-localized, controlled drug delivery, this can potentially lead to a new nonsurgical approach for AAA wall repair in the future.

Hypoxia in Skin Cancer: Molecular Basis and Clinical Implications

Skin cancer is one of the most prevalent cancers in the Caucasian population. In the United States, it is estimated that at least one in five people will develop skin cancer in their lifetime, leading to significant morbidity and a healthcare burden. Skin cancer mainly arises from cells in the epidermal layer of the skin, where oxygen is scarce. There are three main types of skin cancer: malignant melanoma, basal cell carcinoma, and squamous cell carcinoma. Accumulating evidence has revealed a critical role for hypoxia in the development and progression of these dermatologic malignancies. In this review, we discuss the role of hypoxia in treating and reconstructing skin cancers. We will summarize the molecular basis of hypoxia signaling pathways in relation to the major genetic variations of skin cancer.

Notch Signaling Suppresses Melanoma Tumor Development in BRAF/Pten Mice

Both oncogenic and tumor suppressor roles have been assigned to Notch signaling in melanoma. In clinical trials, Notch inhibitors proved to be ineffective for melanoma treatment. Notch signaling has also been implicated in melanoma transdifferentiation, a prognostic feature in primary melanoma. In this study, we investigated the role of Notch signaling in melanoma tumor development and growth using the genetic model of mouse melanoma by crossing BRAFCA/+/Pten+/+/Tyr-CreER+ (B) and BRAFCA/+/Pten-/-/Tyr-CreER + (BP) mice with Notch1 or Notch2 floxed allele mice. The topical application of tamoxifen induced tumors in BP mice but not in B mice with or without the deletion of either Notch1 or Notch2. These data show that the loss of either Notch1 nor Notch2 can substitute the tumor suppressor function of Pten in BRAFV600E-induced melanomagenesis. However, in Pten-null background, the loss of either Notch1 or Notch2 appeared to accelerate BRAFV600E-induced tumor development, suggesting a tumor suppressor role for Notch1 and Notch2 in BRAFV600E/Pten-null driven melanomagenesis. Quantitative immunochemical analysis of a human cutaneous melanoma tissue microarray that consists of >100 primary tumors with complete clinical history showed a weak to moderate correlation between NOTCH protein levels and clinical and pathological parameters. Our data show that Notch signaling is involved during melanomagenesis and suggest that the identification of genes and signaling pathways downstream of Notch could help devise strategies for melanoma prevention.

MECP2 promotes the migration and invasion of gastric cancer cells by modulating the Notch1/c-Myc/mTOR signaling pathways by suppressing FBXW7 transcription

Methyl-CpG-binding protein 2 (MECP2), an epigenetic regulatory factor, promotes the carcinogenesis and progression of a number of cancers. However, its role in the migration and invasion of gastric cancer (GC), as well as the underlying molecular mechanisms, remain unclear. In this study, we found that MECP2 promoted the migration, invasion and metastasis of GC cells. Investigation of the molecular mechanism revealed that MECP2 repressed F-box and WD40 domain protein 7 (FBXW7) transcription in GC by binding to the methylated CpG sites in the FBXW7 promoter region. MECP2 expression was markedly negatively correlated with the FBXW7 level in GC tissues. FBXW7 expression was significantly downregulated in GC tissues and cell lines, and low FBXW7 expression was correlated with unfavorable clinicopathologic features. FBXW7 inhibited cell migration and invasion by regulating the Notch1/c-Myc/mTOR signaling pathways, and knockdown of FBXW7 reversed the effects of silencing MECP2. Moreover, MECP2 upregulated the Notch1/c-Myc/mTOR signaling pathways by inhibiting FBXW7 expression at the transcriptional level. This study demonstrates that MECP2 promotes the migration and invasion of GC cells by modulating the Notch1/c-Myc/mTOR signaling pathways via suppression of FBXW7 transcription. These findings suggest that MECP2 may be a novel effective therapeutic target in GC.

Curcumin Inhibits the Growth and Metastasis of Melanoma via miR-222-3p/SOX10/Notch Axis

Background

The aim of this study was to investigate the effect of curcumin on melanoma and its mechanism.

Methods

Curcumin (0, 0.125, 0.25, or 0.5 mg/ml) was utilized to treat A375 and HT144 cell lines. The MTT analysis was used to confirm the proliferation ability. Wound healing and transwell analysis showed the migration and invasion ability. Immunofluorescence assay was used to demonstrate the effect of curcumin on SOX10 expression. Multiple bioinformatic analysis to confirm the SOX10 associated miRNA. The correlation of miR-222-3p and SOX10 was detected by Luciferase reporter assays. qRT-PCR showed the miR-222-3p level. Western blot analyzed the expression of SOX10, Notch1, and HES1 in melanoma cell treated with or without miR-222-3p inhibitor.

Results

Curcumin could inhibit the proliferation, migration, and invasion of melanoma cells. Furthermore, curcumin repress the expression of SOX10, Notch1, and HES-1, and increase the expression of miR-222-3p. And the miR-222-3p could directly target to SOX10 mRNA to inhibit its expression. In addition, inhibition of miR-222-3p expression reversed the inhibitory effect of curcumin the growth of melanoma cells.

Conclusion

Curcumin enhances the miR-222-3p level to reduce SOX10 expression, and ultimately inactivates the Notch pathway in repressing melanoma proliferation, migration, and invasion.

Intrauterine growth restriction neonates present with increased angiogenesis through the Notch1 signaling pathway

Intrauterine growth restriction (IUGR) is associated with increased perinatal mortality and morbidity, and plays an important role in the development of adult cardiovascular diseases. This study brings forward a hypothesis that Human umbilical vein endothelial cells (HUVECs) from IUGR newborns present dysfunctions and varying changes of signaling pathways as compared to the Control group. Similar pathways may also be present in pulmonary or systemic vasculatures. HUVECs were derived from newborns. There were three groups according to the different fetal origins: normal newborns (Control), IUGR from poor maternal nutrition (IUGR1), and pregnancy-induced hypertension (IUGR2). We found that IUGR-derived HUVECs showed a proliferative phenotype compared to those from normal subjects. Interestingly, two types IUGR could cause varying degrees of cellular dysfunction. Meanwhile, the Notch1 signaling pathway showed enhanced activation in the two IUGR-induced HUVECs, with subsequent activation of Akt or extracellular signal regulated protein kinases1/2 (ERK1/2). Pharmacological inhibition or gene silencing of Notch1 impeded the proliferative phenotype of IUGR-induced HUVECs and reduced the activation of ERK1/2 and AKT. In summary, elevated Notch1 levels might play a crucial role in IUGR-induced HUVECs disorders through the activation of ERK1/2 and AKT. These pathways could be potential therapeutic targets for prevention of the progression of IUGR associated diseases later in life.

Signal pathways of melanoma and targeted therapy

Melanoma is the most lethal skin cancer that originates from the malignant transformation of melanocytes. Although melanoma has long been regarded as a cancerous malignancy with few therapeutic options, increased biological understanding and unprecedented innovations in therapies targeting mutated driver genes and immune checkpoints have substantially improved the prognosis of patients. However, the low response rate and inevitable occurrence of resistance to currently available targeted therapies have posed the obstacle in the path of melanoma management to obtain further amelioration. Therefore, it is necessary to understand the mechanisms underlying melanoma pathogenesis more comprehensively, which might lead to more substantial progress in therapeutic approaches and expand clinical options for melanoma therapy. In this review, we firstly make a brief introduction to melanoma epidemiology, clinical subtypes, risk factors, and current therapies. Then, the signal pathways orchestrating melanoma pathogenesis, including genetic mutations, key transcriptional regulators, epigenetic dysregulations, metabolic reprogramming, crucial metastasis-related signals, tumor-promoting inflammatory pathways, and pro-angiogenic factors, have been systemically reviewed and discussed. Subsequently, we outline current progresses in therapies targeting mutated driver genes and immune checkpoints, as well as the mechanisms underlying the treatment resistance. Finally, the prospects and challenges in the development of melanoma therapy, especially immunotherapy and related ongoing clinical trials, are summarized and discussed.

Melanoma Plasticity: Promoter of Metastasis and Resistance to Therapy

Melanoma is the deadliest form of skin cancer. Although targeted therapies and immunotherapies have revolutionized the treatment of metastatic melanoma, most patients are not cured. Therapy resistance remains a significant clinical challenge. Melanoma comprises phenotypically distinct subpopulations of cells, exhibiting distinct gene signatures leading to tumor heterogeneity and favoring therapeutic resistance. Cellular plasticity in melanoma is referred to as phenotype switching. Regardless of their genomic classification, melanomas switch from a proliferative and differentiated phenotype to an invasive, dedifferentiated and often therapy-resistant state. In this review we discuss potential mechanisms underpinning melanoma phenotype switching, how this cellular plasticity contributes to resistance to both targeted therapies and immunotherapies. Finally, we highlight novel strategies to target plasticity and their potential clinical impact in melanoma.

NOTCH signaling: Journey of an evolutionarily conserved pathway in driving tumor progression and its modulation as a therapeutic target

Notch signaling, an evolutionarily conserved signaling cascade, is critical for normal biological processes of cell differentiation, development, and homeostasis. Deregulation of the Notch signaling pathway has been associated with tumor progression. Thus, Notch presents as an interesting target for a variety of cancer subtypes and its signaling mechanisms have been actively explored from the therapeutic viewpoint. However, besides acting as an oncogene, Notch pathway can possess also tumor suppressive functions, being implicated in inhibition of cancer development. Given such interesting dual and dynamic role of Notch, in this review, we discuss how the evolutionarily conserved Notch signaling pathway drives hallmarks of tumor progression and how it could be targeted for a promising treatment and management of cancer. In addition, the up-to-date information on the inhibitors currently under clinical trials for Notch targets is presented along with how NOTCH inhibitors can be used in conjunction with established chemotherapy/radiotherapy regimes.

Aetiology and Pathogenesis of Cutaneous Melanoma: Current Concepts and Advances

Melanoma develops from malignant transformations of the pigment-producing melanocytes. If located in the basal layer of the skin epidermis, melanoma is referred to as cutaneous, which is more frequent. However, as melanocytes are be found in the eyes, ears, gastrointestinal tract, genitalia, urinary system, and meninges, cases of mucosal melanoma or other types (e.g., ocular) may occur. The incidence and morbidity of cutaneous melanoma (cM) are constantly increasing worldwide. Australia and New Zealand are world leaders in this regard with a morbidity rate of 54/100,000 and a mortality rate of 5.6/100,000 for 2015. The aim of this review is to consolidate and present the data related to the aetiology and pathogenesis of cutaneous melanoma, thus rendering them easier to understand. In this article we will discuss these problems and the possible impacts on treatment for this disease.

Plasticity of Cancer Stem Cell: Origin and Role in Disease Progression and Therapy Resistance

In embryonic development and throughout life, there are some cells can exhibit phenotypic plasticity. Phenotypic plasticity is the ability of cells to differentiate into multiple lineages. In normal development, plasticity is highly regulated whereas cancer cells re-activate this dynamic ability for their own progression. The re-activation of these mechanisms enables cancer cells to acquire a cancer stem cell (CSC) phenotype- a subpopulation of cells with increased ability to survive in a hostile environment and resist therapeutic insults. There are several contributors fuel CSC plasticity in different stages of disease progression such as a complex network of tumour stroma, epidermal microenvironment and different sub-compartments within tumour. These factors play a key role in the transformation of tumour cells from a stable condition to a progressive state. In addition, flexibility in the metabolic state of CSCs helps in disease progression. Moreover, epigenetic changes such as chromatin, DNA methylation could stimulate the phenotypic change of CSCs. Development of resistance to therapy due to highly plastic behaviour of CSCs is a major cause of treatment failure in cancers. However, recent studies explored that plasticity can also expose the weaknesses in CSCs, thereby could be utilized for future therapeutic development. Therefore, in this review, we discuss how cancer cells acquire the plasticity, especially the role of the normal developmental process, tumour microenvironment, and epigenetic changes in the development of plasticity. We further highlight the therapeutic resistance property of CSCs attributed by plasticity. Also, outline some potential therapeutic options against plasticity of CSCs. Graphical Abstract .

Human umbilical cord mesenchymal stem cells in type 2 diabetes mellitus: the emerging therapeutic approach

The umbilical cord has been proved to be an easy-access, reliable, and useful source of mesenchymal stem cells (MSC) for clinical applications due to its primitive, immunomodulatory, non-immunogenic, secretory and paracrine, migratory, proliferative, and multipotent properties. This set of characteristics has recently attracted great research interest in the fields of nanotechnology and regenerative medicine and cellular therapy. Accumulating evidence supports a pronounced therapeutic potential of MSC in many different pathologies, from hematology to immunology, wound-healing, tissue regeneration, and oncology. Diabetes mellitus, branded the epidemic of the century, is considered a chronic metabolic disorder, representing a major burden for health system sustainability and an important public health challenge to modern societies. The available treatments for type 2 diabetes mellitus (T2DM) still rely mainly on combinations of oral antidiabetic agents with lifestyle and nutritional adjustments. Despite the continuous development of novel and better hypoglycemic drugs, their efficacy is limited in the installment and progression of silent T2DM complications. T2DM comorbidities and mortality rates still make it a serious, common, costly, and long-term manageable disease. Recently, experimental models, preclinical observations, and clinical studies have provided some insights and preliminary promising results using umbilical cord MSCs to treat and manage diabetes. This review focuses on the latest research and applications of human-derived umbilical cord MSC in the treatment and management of T2DM, exploring and systematizing the key effects of both umbilical cord MSC and its factor-rich secretome accordingly with the major complications associated to T2DM.

Effects of HIF-1α on renal fibrosis in cisplatin-induced chronic kidney disease

Cisplatin (Cis) can cause chronic kidney disease (CKD) and promote renal fibrosis, but the underlying mechanism is not fully understood. Hypoxia inducible factor-1α (HIF-1α) can promote renal fibrosis in some kidney diseases, but its role in Cis-induced CKD is still unknown. Notch-1 is a recognized molecule that promotes renal fibrosis under pathological circumstances, and evidence shows that HIF-1α and Notch-1 are closely related to each other. In the present study, mice with HIF-1α gene knockout in proximal tubular cells (PTCs) (PT-HIF-1α-KO) were generated and treated with Cis to induce CKD. A human proximal tubular cell line (HK-2) and primary mouse PTCs were used for in vitro studies. The results showed that HIF-1α was increased in the kidneys of Cis-treated wild-type mice, accompanied by elevated Notch-1, Notch-1 intracellular domain (N1ICD), Hes-1 and renal fibrosis. However, these alterations were partially reversed in PT-HIF-1α-KO mice. Similar results were observed in HK-2 cells and primary mouse PTCs. In addition, treating the cells with Cis induced a marked interaction of HIF-1α and N1ICD. Further inhibiting Notch-1 significantly reduced cellular fibrogenesis but did not affect HIF-1α expression. The data suggested that HIF-1α could promote renal fibrosis in Cis-induced CKD by activating Notch-1 both transcriptionally and post-transcriptionally and that HIF-1α may serve as a potential therapeutic target for Cis-induced CKD.

Hypoxia-dependent drivers of melanoma progression

Hypoxia, a condition of low oxygen availability, is a hallmark of tumour microenvironment and promotes cancer progression and resistance to therapy. Many studies reported the essential role of hypoxia in regulating invasiveness, angiogenesis, vasculogenic mimicry and response to therapy in melanoma. Melanoma is an aggressive cancer originating from melanocytes located in the skin (cutaneous melanoma), in the uveal tract of the eye (uveal melanoma) or in mucosal membranes (mucosal melanoma). These three subtypes of melanoma represent distinct neoplasms in terms of biology, epidemiology, aetiology, molecular profile and clinical features.In this review, the latest progress in hypoxia-regulated pathways involved in the development and progression of all melanoma subtypes were discussed. We also summarized current knowledge on preclinical studies with drugs targeting Hypoxia-Inducible Factor-1, angiogenesis or vasculogenic mimicry. Finally, we described available evidence on clinical studies investigating the use of Hypoxia-Inducible Factor-1 inhibitors or antiangiogenic drugs, alone or in combination with other strategies, in metastatic and adjuvant settings of cutaneous, uveal and mucosal melanoma.Hypoxia-Inducible Factor-independent pathways have been also reported to regulate melanoma progression, but this issue is beyond the scope of this review.As evident from the numerous studies discussed in this review, the increasing knowledge of hypoxia-regulated pathways in melanoma progression and the promising results obtained from novel antiangiogenic therapies, could offer new perspectives in clinical practice in order to improve survival outcomes of melanoma patients.

Interleukin-17 activates and synergizes with the notch signaling pathway in the progression of pancreatic ductal adenocarcinoma

Interleukin (IL)-17 is a prominent cytokine that promotes pancreatic intraepithelial neoplasia (PanIN) and pancreatic ductal adenocarcinoma (PDAC) and is associated with the oncogenic pathways in tumor progression. However, the mechanism and therapeutic value of the IL-17 axis remain unclear. In this study, we verified the activation of the IL-17 and Notch pathways in PanIN/PDAC via complementary approaches and validated their pro-tumor effects on tumor progression. Additionally, we found a positive correlation between IL-17 and Notch; the IL-17 axis can upregulate Notch activity via the canonical NF-κB pathway in vitro, thus synergistically promoting PanIN/PDAC. Furthermore, we observed that the co-inhibition of IL-17 and the Notch pathway can enhance the therapeutic effect by restricting tumor growth in vivo. Our study highlights the synergistic effect of the IL-17 axis and Notch pathway in promoting PanIN/PDAC and further suggests that IL-17-Notch co-inhibition is a novel therapeutic strategy with superior potential in treating PDAC.

The early antitumor immune response is necessary for tumor growth: Re-visiting Prehn's hypothesis in the human melanoma system

Early events responsible of tumor growth in patients with a normal immune system are poorly understood. Here, we discuss, in the context of human melanoma, the Prehn hypothesis according to which a weak antitumor immune response may be required for tumor growth before weakly or non-immunogenic tumor cell subpopulations are selected by the immune system.

Hypoxia in Solid Tumors: How Low Oxygenation Impacts the "Six Rs" of Radiotherapy

Radiotherapy is an important component of cancer treatment, with approximately 50% of all cancer patients receiving radiation therapy during their course of illness. Nevertheless, solid tumors frequently exhibit hypoxic areas, which can hinder therapies efficacy, especially radiotherapy one. Indeed, hypoxia impacts the six parameters governing the radiotherapy response, called the « six Rs of radiation biology » (for Radiosensitivity, Repair, Repopulation, Redistribution, Reoxygenation, and Reactivation of anti-tumor immune response), by inducing pleiotropic cellular adaptions, such as cell metabolism rewiring, epigenetic landscape remodeling, and cell death weakening, with significant clinical repercussions. In this review, according to the six Rs, we detail how hypoxia, and associated mechanisms and pathways, impact the radiotherapy response of solid tumors and the resulting clinical implications. We finally illustrate it in hypoxic endocrine cancers through a focus on anaplastic thyroid carcinomas.

Identification and quantification of notch receptors in human cutaneous melanoma using molecular biology techniques: literature review

Background

The Notch signaling pathway and its modulators are directly related to growth, verticalization and metastasis in melanoma, being a possible therapeutic target for the treatment of this type of cancer. There are several methods of molecular biology to identify and quantify Notch receptors and it is essential to study them for understanding the different results, advantages and disadvantages of each.

Main body

The present study brings a bibliographic review on the molecular biology methods used in the identification and quantification of these molecules, aiming to facilitate research involving Notch receptors in human melanoma. We identified as main methods of molecular biology Western Blotting, Quantitative real-time polymerase chain reaction and DNA microarrays. A brief description of these methodologies is made and the advantages and disadvantages of each are discussed. Results concerning the function of this pathway are also discussed.

Short conclusion

It is known that the activation of Notch receptors is tumorigenic in most cases, however, depending on the microenvironment, it can provide tumor suppression. The adequate choice and use of the methodology for identification and quantification of Notch receptors is essential for the progress of knowledge of this important signaling pathway, which, certainly, will allow advances in the treatment of cutaneous melanoma.

Long-Term Inhibition of Notch in A-375 Melanoma Cells Enhances Tumor Growth Through the Enhancement of AXIN1, CSNK2A3, and CEBPA2 as Intermediate Genes in Wnt and Notch Pathways

Notch suppression by gamma-secretase inhibitors is a valid approach against melanoma. However, most of studies have evaluated the short-term effect of DAPT on tumor cells or even cancer stem cells. In the present study, we surveyed the short-term and long-term effects of DAPT on the stem cell properties of A375 and NA8 as melanoma cell lines. The effects of DAPT were tested both in vitro and in vivo using xenograft models. In A375 with B-raf mutation, DAPT decreased the level of NOTCH1, NOTH2, and HES1 as downstream genes of the Notch pathway. This was accompanied by enhanced apoptosis after 24 h treatment, arrest in the G₂₋M phase, and impaired ability of colony and melanosphere formation at the short term. Moreover, tumor growth also reduced during 13 days of treatment. However, long-term treatment of DAPT promoted tumor growth in the xenograft model and enhanced the number and size of colonies and spheroids in vitro. The gene expression studies confirmed the up-regulation of Wnt and Notch downstream genes as well as AXIN1, CSNK2A3, and CEBPA2 following the removal of Notch inhibitor in vitro and in the xenograft model. Moreover, the Gompertz-based mathematical model determined a new drug resistance term in the present study. Our data supported that the long-term and not short-term inhibition of Notch by DAPT may enhance tumor growth and motility through up-regulation of AXIN1, CSNK2A3, and CEBPA2 genes in B-raf mutated A375 cells.

Human peroxidasin 1 promotes angiogenesis through ERK1/2, Akt, and FAK pathways

Aims

The term angiogenesis refers to sprouting of new blood vessels from pre-existing ones. The angiogenic process involves cell migration and tubulogenesis requiring interaction between endothelial cells and the extracellular matrix. Human peroxidasin 1 (hsPxd01) is a multidomain heme peroxidase found embedded in the basement membranes. As it promotes the stabilization of extracellular matrix, we investigated its possible role in angiogenesis both in vitro and in vivo.

Methods and results

We analysed the effects of peroxidasin 1 gene silencing and supplementation by recombinant hsPxd01 in TeloHAEC endothelial cells on cell migration, tubulogenesis in matrigel, and intracellular signal transduction as assessed by kinase phosphorylation and expression of pro-angiogenic genes as measured by qRT-PCR. We further evaluated the angiogenic potential of recombinant peroxidasin in a chicken chorioallantoic membrane model. RNA silencing of endogenous hsPxd01 significantly reduced tube formation and cell migration, whereas supplementation by the recombinant peroxidase promoted tube formation in vitro and stimulated vascularization in vivo through its catalytic activity. Moreover, recombinant hsPxd01 promoted phosphorylation of Extracellular signal-Regulated Kinases (ERK1/2), Protein kinase B (Akt), and Focal Adhesion Kinase (FAK), and induced the expression of pro-angiogenic downstream genes: Platelet Derived Growth Factor Subunit B (PDGFB), endothelial-derived Heparin Binding EGF-like growth factor (HB-EGF), CXCL-1, Hairy-Related Transcription Factor 1 (HEY-1), DNA-binding protein inhibitor (ID-2), Snail Family Zinc Finger 1 (SNAI-1), as well as endogenous hsPxd01. However, peroxidasin silencing significantly reduced Akt and FAK phosphorylation but induced ERK1/2 activation after supplementation by recombinant hsPxd01. While hsPxd01 silencing significantly reduced expression of HEY-1, ID-2, and PDGFB, it did not affect expression of SNAI-1, HB-EGF, and CXCL-1 after supplementation by recombinant hsPxd01.

Conclusion

Our findings suggest a role of enzymatically active peroxidasin 1 as a pro-angiogenic peroxidase and a modulator of ERK1/2, Akt and FAK signalling.

Abnormal overexpression of G9a in melanoma cells promotes cancer progression via upregulation of the Notch1 signaling pathway

Malignant melanoma is a type of very dangerous skin cancer. Histone modifiers usually become dysregulated during the process of carcinoma development, thus there is potential for a histone modifier inhibitor as a useful drug for cancer therapy. There is a multitude of evidence regarding the role of G9a, a histone methyltransferase (HMTase), in tumorigenesis. In this study, we first showed that G9a was significantly upregulated in melanoma patients. Using the TCGA database, we found a significantly higher expression of G9a in primary melanoma samples (n = 461) compared to normal skin samples (n = 551). Next, we knocked down G9a in human M14 and A375 melanoma cell lines in vitro via small interfering RNA (siRNA). This resulted in a significant decrease in cell viability, migration and invasion, and an increase in cell apoptosis. UNC0642 is a small molecule inhibitor of G9a that demonstrates minimal cell toxicity and good in vivo pharmacokinetic characteristics. We investigated the role of UNC0642 in melanoma cells, and detected its anti-cancer effects in vitro and in vivo. Next, we treated cells with UNC0642, and observed a significant decrease in cell viability in M14 and A375 cell lines. Furthermore, treatment with UNC0642 resulted in increased apoptosis. In immunocompetent mice bearing A375 engrafts, treatment with UNC0642 inhibited tumor growth. Results of Western blot analysis revealed that administration of UNC0642 or silencing of G9a expression by siRNA reduced Notch1 expression significantly and decreased the level of Hes1 in A375. All in all, the data from our study demonstrates potential of G9a as a therapeutic target in the treatment of melanoma.

Personalized and targeted mutational analysis of multiple second primary melanomas under kinase inhibitors

BACKGROUND

Second primary melanomas (SPMs) are new developed primary melanomas occurring in a subset of patients affected by BRAF-mutated metastatic melanoma during treatment with BRAF-inhibitors. A drug-induced paradoxical activation of mitogen-activated protein kinase (MAPK) signaling pathway in BRAF-wild type/RAS-mutated cells have been proposed as a possible molecular mechanism but data on the mutational status of SPMs are lacking. In order to better understand genetic alterations affecting the biological mechanism of SPMs, we performed a personalized and targeted next-generation sequencing analysis of a patient affected by metastatic melanoma who developed multiple SPMs during treatment with encorafenib (LGX818).

METHODS

Using a cancer panel of 50 genes for solid tumors enriched with a custom panel of 10 genes specifically involved in melanoma pathogenesis, we analyzed the primary melanoma, two SPMs, one benign compound nevus and the normal DNA extracted from blood lymphocytes of the patient.

RESULTS

We identified HRAS Q61 somatic mutation in one SPM developed in a pre-existing nevus. In the primary melanoma, besides the BRAF mutation, we identified the clinically actionable IDH1 R132C somatic mutation. Both SPMs were BRAF wild type. The patient harbors the recently recognized pathogenetic germline variant KDR Q472. We observed that mutations detected in tumor samples involving genes related to melanoma pathogenesis (TP53, PIK3CA, FGFR3, ATF1, KIT, HRAS and MAP2K2) were present in heterozygosis in the germline status of the patient.

CONCLUSIONS

Our results support the paradoxical mechanism of MAPK pathway for SPMs under BRAF inhibitors. Moreover, they suggest that targeted mutational assessment based on matching somatic and germline analysis represent a promising approach to detect the neoplastic landscape of the tumor and to identify most accurate treatment in metastatic melanoma patient.

Notch1 and PI3K/Akt signaling blockers DAPT and LY294002 coordinately inhibit metastasis of gastric cancer through mutual enhancement

PURPOSE

Blockade of either Notch1 or PI3K/Akt pathway inhibits metastasis of gastric cancer. However, whether blockade of both pathways coordinately exerts such an effect remains unknown. In this study, we aimed to investigate the effects of combined treatment with Notch1 signaling blocker DAPT and PI3K/Akt signal blocker LY294002 on metastasis of gastric cancer.

METHODS

Notch intracellular domain (NICD) and phosphorylated Akt (p-Akt) levels in gastric cancer tissues and their adjacent normal tissue samples and gastric cancer SGC7901 and AGS cells and normal GES-1 cells were determined using immunohistochemistry and Western blotting. The effects of combined DAPT and LY294002 on metastasis of gastric cancer were evaluated by examining migration and invasion potential of SGC7901 cells using wound healing and transwell assays, determining changes in the levels of epithelial-mesenchymal transition biomarkers and MMP-9, Notch1, HES1, and phosphorylation of Akt in gastric cancer SGC7901 cells and/or AGS cells in vitro using Western blotting, and metastasis of gastric cancer to lungs in BALB/c nude mice after treatment.

RESULTS

NICD and p-Akt levels were significantly higher in gastric cancer tissues and SGC7901 and AGS cells than those in the normal control and GES-1 cells. Migration and invasion potential of SGC7901 cells, EMT biomarkers and MMP-9 in SGC7901 cells, and metastasis of gastric cancer to lungs in mice were coordinately inhibited by DAPT and LY294002. In addition, DAPT and LY294002 coordinately inhibited the levels of Notch1, HES1, and p-Akt in gastric cancer cells.

CONCLUSION

DAPT and LY294002 coordinately inhibited metastasis of gastric cancer through mutual enhancement.

Phenotypic Plasticity: Driver of Cancer Initiation, Progression, and Therapy Resistance

Our traditional understanding of phenotypic plasticity in adult somatic cells comprises dedifferentiation and transdifferentiation in the context of tissue regeneration or wound healing. Although dedifferentiation is central to tissue repair and stemness, this process inherently carries the risk of cancer initiation. Consequently, recent research suggests phenotypic plasticity as a new paradigm for understanding cancer initiation, progression, and resistance to therapy. Here, we discuss how cells acquire plasticity and the role of plasticity in initiating cancer, cancer progression, and metastasis and in developing therapy resistance. We also highlight the epithelial-to-mesenchymal transition (EMT) and known molecular mechanisms underlying plasticity and we consider potential therapeutic avenues.

HIF-1α, NOTCH1, ADAM12, and HB-EGF are overexpressed in mucoepidermoid carcinoma

OBJECTIVE

Intratumoral hypoxia (IH) occurs during cellular proliferation of malignant tumors. This phenomenon is characterized by a decrease in oxygen levels in the neoplastic microenvironment. Throughout this condition, the proteins HIF-1α, NOTCH1, ADAM12, and HB-EGF can be activated, triggering signaling pathways associated with tumor invasiveness through invadopodia formation. This study aimed to evaluate the immunostaining of HIF-1α, NOTCH1, ADAM12, and HBEGF in 19 cases of mucoepidermoid carcinoma (MEC) and 10 samples of salivary glands (control group).

STUDY DESIGN

The immunoperoxidase technique was employed to detect the proteins of interest. The Student t test was used to compare immunoexpression between MEC samples and the control group.

RESULTS

Protein immunostaining was statistically significantly higher in MEC samples than in the control group (P < .01), and the proteins were especially overexpressed in epidermoid cells of MEC.

CONCLUSIONS

We suggest that there is an association between the NOTCH1 signaling pathway activated by IH and the biologic behavior of MEC.

Contribution of KCTD12 to esophageal squamous cell carcinoma

Background

It has been shown that the expression of potassium channel tetramerization domain containing 12 (KCTD12) as a regulator of GABAB receptor signaling is reversely associated with gastrointestinal stromal tumors. In present study we examined the probable role of KCTD12 in regulation of several signaling pathways and chromatin remodelers in esophageal squamous cell carcinoma (ESCC).

Methods

KCTD12 ectopic expression was done in KYSE30 cell line. Comparative quantitative real time PCR was used to assess the expression of stem cell factors and several factors belonging to the WNT/NOTCH and chromatin remodeling in transfected cells in comparison with non-transfected cells.

Results

We observed that the KCTD12 significantly down regulated expression of NANOG, SOX2, SALL4, KLF4, MAML1, PYGO2, BMI1, BRG1, MSI1, MEIS1, EGFR, DIDO1, ABCC4, ABCG2, and CRIPTO1 in transfected cells in comparison with non-transfected cells. Migration assay showed a significant decrease in cell movement in ectopic expressed cells in comparison with non-transfected cells (p = 0.02). Moreover, KCTD12 significantly decreased the 5FU resistance in transfected cells (p = 0.01).

Conclusions

KCTD12 may exert its inhibitory role in ESCC through the suppression of WNT /NOTCH, stem cell factors, and chromatin remodelers and can be introduced as an efficient therapeutic marker.

ICBP90 mediates Notch signaling to facilitate human hepatocellular carcinoma growth

The Notch signaling pathway plays a key role in cell proliferation and development that is closely related to an inverted CCAAT box binding protein (ICBP90), but little is known about whether there is a correlation between Notch signaling and ICBP90. The aim of the current study was to elucidate this. MTT assay and flow cytometry were used to determine the proliferation, cell cycle and apoptosis of HepG2 or Hepa1-6 cells treated by N-[N-(3,5-difluorophenacetyl)-L-alanyl]-S-phenylglycine t-butyl ester (DAPT), a specific inhibitor of the Notch pathway. RT-PCR, Western Blot and in situ immunofluorescence staining were employed to examine expression of ICBP90 in the cells. DAPT caused inhibition of the activation of the Notch signaling pathway, followed by preventing the cells at the G0/G1 phases to enter S and G2/M phases. ICBP90 and Hes-1 proteins were highly expressed in the untreated cells. The reduced levels of Notch intracellular domain (NICD) protein were observed in the DAPT-treated cells, thereby bringing about the down-regulation of ICBP90 with the increment of the DAPT dose. Consistent with this, knockdown of the Hes-1 gene, which encodes a critical transcriptional factor in the Notch pathway, also led to the attenuation of ICBP90. On the contrary, Jagged-1, a Notch ligand, facilitated ICBP90 production. Adriamycin could result in the reduction of ICBP90, which was not accompanied with the alteration of Hes-1. ICBP90 was almost fully distributed within the nuclei, but Hes-1 was visible within both the cytoplasm and nuclei. Our novel findings strongly indicate that inactivation of the Notch signaling pathway impedes hepatocellular carcinoma progress via reduction of ICBP90.

Suppression of Notch1 and AKT mediated epithelial to mesenchymal transition by Verrucarin J in metastatic colon cancer

Epithelial to mesenchymal transition (EMT) in colorectal cancer (CRC) has been attributed to activation of AKT and Notch1 signaling pathways. As EMT corresponds to increased aggressiveness of CRC, approaches that prevent metastasis by targeting AKT/Notch1 pathways are at the forefront of current research paradigms. This study examined the anti-metastatic potential of Verrucarin J (VJ), a small molecule, in CRC cells overexpressing AKT and Notch1. VJ significantly inhibited AKT/HCT 116 cell growth by acting on the AKT/NFκB/Bcl-2 signaling axis and initiated apoptotic signaling as was evident from increased expression of pro-apoptotic markers such as cleaved PARP, cleaved caspase 3, and cleaved caspase 9. Also, VJ inhibited the cell growth in AKT/Notch1-overexpressing CRC cells and abrogated EMT. The down-regulation of AKT and Notch1 signaling was apparent in immunoblot analysis and corresponded with down-regulation of mesenchymal markers including Snail, and β-catenin. Intraperitoneal administration of VJ in control (pCMV/HCT 116) and AKT/HCT 116 mice significantly suppressed AKT-induced tumor growth in a xenograft model. In addition, down-regulation of prosurvival markers as well as AKT and Notch1 was observed in the immunohistochemical analysis of the xenografted tumors. In conclusion, our study substantiates the role of AKT and Notch1 in cell proliferation, angiogenesis, and EMT of CRC cells and demonstrates that VJ may be a viable therapeutic option to counter AKT-induced cell proliferation and tumor outgrowth in CRC.

Inhibiting Notch1 enhances immunotherapy efficacy in melanoma by preventing Notch1 dependent immune suppressive properties

We have previously shown that Notch1 plays a critical role in modulating melanoma tumor cell growth and survival. Here we show that Notch1 also contributes to an immune-suppressive tumor microenvironment (TME). Notch1 inhibition reduces immune suppressive cells (i.e. MDSCs and Tregs) while allowing the recruitment of functional CD8(+) T cells, leading to a decrease in the Tregs/CD8(+) ratio, a key parameter in assessing positive responses to immune-checkpoint inhibitors. Inhibition of Notch1 improves the antitumor activity of nivolumab and ipilimumab, particularly when given in combination. Mechanistically, tumor-associated Notch1 regulates the expression of several chemokines involved in MDSCs and Tregs recruitment. Among them, CCL5, IL6 and IL8, or MIP2 in mouse, were consistently reduced by Notch1 depletion in several human and mouse melanoma cell lines. Notch1 controls the transcription of IL8 and IL6; and the secretion of CCL5 likely by inhibiting the expression of SNAP23, a member of the SNAREs family of proteins involved in cell exocytosis. Inhibition of SNAP23 decreases CCL5 secretion similarly to Notch1 inhibition. Hence, targeting Notch1 would affect both melanoma intrinsic growth/survival properties, and provide an immune-responsive TME, thus improving immune therapy efficacy.

The multiple usages of Notch signaling in development, cell differentiation and cancer

Notch is a well-conserved signaling pathway all through evolution that is crucial to specify different cell fates. Although there is a strong context dependent component in each decision, the basic mechanisms that originate from the interplay among ligands and receptors is greatly preserved. In this review we will cover the latest findings on the different mechanisms for Notch activation and signaling. The regulation of this pathway is essential to understand development, cell differentiation and disease.

The Notch Pathway in Breast Cancer Progression

Objective

Notch signaling pathway is a vital parameter of the mammalian vascular system. In this review, the authors summarize the current knowledge about the impact of the Notch signaling pathway in breast cancer progression and the therapeutic role of Notch's inhibition.

Methods

The available literature in MEDLINE, PubMed, and Scopus, regarding the role of the Notch pathway in breast cancer progression was searched for related articles from about 1973 to 2017 including terms such as “Notch,” “Breast Cancer,” and “Angiogenesis.” Results. Notch signaling controls the differentiation of breast epithelial cells during normal development. Studies confirm that the Notch pathway has a major participation in breast cancer progression through overexpression and/or abnormal genetic type expression of the notch receptors and ligands that determine angiogenesis. The cross-talk of Notch and estrogens, the effect of Notch in breast cancer stem cells formation, and the dependable Notch overexpression during breast tumorigenesis have been studied enough and undoubtedly linked to breast cancer development. The already applied therapeutic inhibition of Notch for breast cancer can drastically change the course of the disease.

Conclusion

Current data prove that Notch pathway has a major participation and multiple roles during breast tumor progression. Inhibition of Notch receptors and ligands provides innovative therapeutic results and could become the therapy of choice in the next few years, even though further research is needed to reach safe conclusions.

The Notch Inhibitors Isolated from Nerium indicum

Notch signaling plays a crucial role in differentiation and cell maintenance, but once aberrantly activated, it contributes to cancer progression. Notch inhibitors were isolated from plant extracts and tested using an originally constructed cell-based assay system. We isolated eight compounds from Nerium indicum that showed inhibition of the Notch signaling pathway. HES1 and HES5 are target genes of the Notch signaling pathway, and oleandrin (1) decreased the protein levels of HES1 and HES5 in assay cells. Oleandrin (1) showed potent cytotoxicity against HPB-ALL cells and decreased HES1 and the Notch intracellular domain in these cells. The main mechanism of action of 1 appears to be inhibition of Notch signaling by acceleration of Notch intracellular domain degradation.

The Notch inhibitor cowanin accelerates nicastrin degradation

Aberrant activation of Notch signaling contributes to the pathogenesis of several different types of cancer, and Notch pathway inhibitors may have significant therapeutic potential. Using a unique cell-based assay system, we isolated twelve compounds, including one new natural product from Garcinia speciosa, that inhibit the Notch signaling pathway. HES1 and HES5 are target genes of the Notch cascade, and compound 2, referred to as cowanin, decreased the protein levels of HES1 and HES5 in assay cells. Furthermore, cowanin (2) showed potent cytotoxicity against human leukemic HPB-ALL cells. The Notch signaling inhibitory activity of cowanin (2) is linked to the increased degradation of nicastrin, which is one of the components of the γ-secretase complex. To the best of our knowledge, this is the first example of a compound with Notch pathway inhibitory activity mediated by nicastrin degradation.

Targeting Notch enhances the efficacy of ERK inhibitors in BRAF-V600E melanoma

The discovery of activating BRAF mutations in approximately 50% of melanomas has led to the development of MAPK pathway inhibitors, which have transformed melanoma therapy. However, not all BRAF-V600E melanomas respond to MAPK inhibition. Therefore, it is important to understand why tumors with the same oncogenic driver have variable responses to MAPK inhibitors. Here, we show that concurrent loss of PTEN and activation of the Notch pathway is associated with poor response to the ERK inhibitor SCH772984, and that co-inhibition of Notch and ERK decreased viability in BRAF-V600E melanomas. Additionally, patients with low PTEN and Notch activation had significantly shorter progression free survival when treated with BRAF inhibitors. Our studies provide a rationale to further develop combination strategies with Notch antagonists to maximize the efficacy of MAPK inhibition in melanoma. Our findings should prompt the evaluation of combinations co-targeting MAPK/ERK and Notch as a strategy to improve current therapies and warrant further evaluation of co-occurrence of aberrant PTEN and Notch activation as predictive markers of response to therapy.

JMJD3 and NF-κB-dependent activation of Notch1 gene is required for keratinocyte migration during skin wound healing

It has been shown that epigenetic regulation plays an important role in skin wound healing. We previously found that histone H3K27me3 demethylase JMJD3 regulates inflammation and cell migration in keratinocyte wound healing. In this study, we identified Notch1 as a direct target of JMJD3 and NF-κB in wounded keratinocytes using in vitro cell and in vivo animal models. We found that Notch1 is up-regulated in the wound edge and its expression is dependent on JMJD3 and NF-κB in wounded keratinocytes. We also found that Notch1 activates the expression of RhoU and PLAU gene, which are critical regulators of cell migration. Consistently, depletion or inactivation of Notch1 resulted in decreased filopodia formation, increased focal adhesion and actin stress fiber, leading to reduced keratinocyte migration and skin wound healing. Thus, our findings provide the molecular mechanism involving JMJD3/NF-κB-Notch pathway in keratinocyte wound healing.

A Notch-independent mechanism contributes to the induction of Hes1 gene expression in response to hypoxia in P19 cells

Hes1 is a Notch target gene that plays a major role during embryonic development. Previous studies have shown that HIF-1α can interact with the Notch intracellular domain and enhance Notch target gene expression. In this study, we have identified a Notch-independent mechanism that regulates the responsiveness of the Hes1 gene to hypoxia. Using P19 cells we show that silencing the Notch DNA binding partner CSL does not prevent hypoxia-dependent upregulation of Hes1 expression. In contrast to CSL, knockdown of HIF-1α or Arnt expression prevents Hes1 induction in hypoxia. Deletion analysis of the Hes1 promoter identified a minimal region near the transcription start site that is still responsive to hypoxia. In addition, we show that mutating the GA-binding protein (GABP) motif significantly reduced Hes1 promoter-responsiveness to hypoxia or to HIF-1 overexpression whereas mutation of the hypoxia-responsive element (HRE) present in this region had no effect. Chromatin immunoprecipitation assays demonstrated that HIF-1α binds to the proximal region of the Hes1 promoter in a Notch-independent manner. Using the same experimental approach, the presence of GABPα and GABPβ1 was also observed in the same region of the promoter. Loss- and gain-of-function studies demonstrated that Hes1 gene expression is upregulated by hypoxia in a GABP-dependent manner. Finally, co-immunoprecipitation assays demonstrated that HIF-1α but not HIF-2α is able to interact with either GABPα or GABPβ1. These results suggest a Notch-independent mechanism where HIF-1 and GABP contribute to the upregulation of Hes1 gene expression in response to hypoxia.

Cross-Kingdom Regulation of Putative miRNAs Derived from Happy Tree in Cancer Pathway: A Systems Biology Approach

MicroRNAs (miRNAs) are well-known key regulators of gene expression primarily at the post-transcriptional level. Plant-derived miRNAs may pass through the gastrointestinal tract, entering into the body fluid and regulate the expression of endogenous mRNAs. Camptotheca acuminata, a highly important medicinal plant known for its anti-cancer potential was selected to investigate cross-kingdom regulatory mechanism and involvement of miRNAs derived from this plant in cancer-associated pathways through in silico systems biology approach. In this study, total 33 highly stable putative novel miRNAs were predicted from the publically available 53,294 ESTs of C. acuminata, out of which 14 miRNAs were found to be regulating 152 target genes in human. Functional enrichment, gene-disease associations and network analysis of these target genes were carried out and the results revealed their association with prominent types of cancers like breast cancer, leukemia and lung cancer. Pathways like focal adhesion, regulation of lipolysis in adipocytes and mTOR signaling pathways were found significantly associated with the target genes. The regulatory network analysis showed the association of some important hub proteins like GSK3B, NUMB, PEG3, ITGA2 and DLG2 with cancer-associated pathways. Based on the analysis results, it can be suggested that the ingestion of the C. acuminata miRNAs may have a functional impact on tumorigenesis in a cross-kingdom way and may affect the physiological condition at genetic level. Thus, the predicted miRNAs seem to hold potentially significant role in cancer pathway regulation and therefore, may be further validated using in vivo experiments for a better insight into their mechanism of epigenetic action of miRNA.

The natural compound fucoidan from New Zealand Undaria pinnatifida synergizes with the ERBB inhibitor lapatinib enhancing melanoma growth inhibition

Melanoma remains one of the most aggressive and therapy-resistant cancers. Finding new treatments to improve patient outcomes is an ongoing effort. We previously demonstrated that melanoma relies on the activation of ERBB signaling, specifically of the ERBB3/ERBB2 cascade. Here we show that melanoma tumor growth is inhibited by 60% over controls when treated with lapatinib, a clinically approved inhibitor of ERBB2/EGFR. Importantly, tumor growth is further inhibited to 85% when the natural compound fucoidan from New Zealand U. pinnatifida is integrated into the treatment regimen. Fucoidan not only enhances tumor growth inhibition, it counteracts the morbidity associated with prolonged lapatinib treatment. Fucoidan doubles the cell killing capacity of lapatinib. These effects are associated with a further decrease in AKT and NFκB signaling, two key pathways involved in melanoma cell survival. Importantly, the enhancing cell killing effects of fucoidan can be recapitulated by inhibiting ERBB3 by either a specific shRNA or a novel, selective ERBB3 neutralizing antibody, reiterating the key roles played by this receptor in melanoma. We therefore propose the use of lapatinib or specific ERBB inhibitors, in combination with fucoidan as a new treatment of melanoma that potentiates the effects of the inhibitors while protecting from their potential side effects.

Inflammation and Notch signaling: a crosstalk with opposite effects on tumorigenesis

The Notch cascade is a fundamental and highly conserved pathway able to control cell-fate. The Notch pathway arises from the interaction of one of the Notch receptors (Notch1–4) with different types of ligands; in particular, the Notch pathway can be activated canonically (through the ligands Jagged1, Jagged2, DLL1, DLL3 or DLL4) or non-canonically (through various molecules shared by other pathways). In the context of tumor biology, the deregulation of Notch signaling is found to be crucial, but it is still not clear if the activation of this pathway exerts a tumor-promoting or a tumor suppressing function in different cancer settings. Untill now, it is well known that the inflammatory compartment is critically involved in tumor progression; however, inflammation, which occurs as a physiological response to damage, can also drive protective processes toward carcinogenesis. Therefore, the role of inflammation in cancer is still controversial and needs to be further clarified. Interestingly, recent literature reports that some of the signaling molecules modulated by the cells of the immune system also belong to or interact with the canonical and non-canonical Notch pathways, delineating a possible link between Notch activation and inflammatory environment. In this review we analyze the hypothesis that specific inflammatory conditions can control the activation of the Notch pathway in terms of biological effect, partially explaining the dichotomy of both phenomena. For this purpose, we detail the molecular links reported in the literature connecting inflammation and Notch signaling in different types of tumor, with a particular focus on colorectal carcinogenesis, which represents a perfect example of context-dependent interaction between malignant transformation and immune response.

Downregulation of Bmi-1 suppresses epithelial‑mesenchymal transition in melanoma

Epithelial-mesenchymal transition (EMT) contributes to the invasion and metastasis of numerous malignant cancers, including melanoma. A significant higher expression of B-lymphoma Moloney murine leukemia virus insertion region-1 (Bmi-1) has been reported in cell lines from metastatic melanoma compared to cell lines from primary melanoma. There are studies that show that knockdown of Bmi-1 could induce E-cadherin expression in melanoma cells. However, the role of Bmi-1 in mediating EMT-like changes in melanoma has not yet been fully studied. In the present study, knockdown of Bmi-1 by shRNA transduction decreased the invasion properties of the cultured human melanoma cells A375 by a Matrigel invasion assay, along with alterations in EMT-related markers E-cadherin, α-catenin, vimentin and N-cadherin. The aforementioned altered expression of EMT markers was verified in BALB/c-nude mouse xenografts. Furthermore, to explore the underlying regulatory mechanism of EMT, we detected the significant downregulation of p-Akt/p‑NF-κB/MMP-2 and the upregulation of PTEN in Bmi-1-silenced A375 cells. The present study demonstrated that knockdown of Bmi-1 significantly inhibited the aggressive behavior of melanoma by reversing EMT-like changes via the PTEN/p-Akt/p‑NF-κB/MMP-2 pathway.

A comprehensive transcriptomic analysis of differentiating embryonic stem cells in response to the overexpression of Mesogenin 1

The mutation of somitogenesis protein Mesogenin 1 (Msgn1) has been widely used to study the direct link between somitogenesis and the development of an embryo. Several studies have used gene expression profiling of somitogenesis to identify the key genes in the process, but few have focused on the pathways involved and the coexpression patterns of associated pathways. Here we employed time-course microarray datasets of differentiating embryonic stem cells by overexpressing the transcription factor Msgn1 from the public database library of Gene Expression Omnibus (GEO). Then we applied gene set enrichment analysis (GSEA) to the datasets and performed candidate transcription factors selection. As a result, several significantly regulated pathways and transcription factors (TFs), as well as some of the specific signaling pathways, were identified during somitogenesis under Msgn1 overexpression, most of which had not been reported previously. Finally, significant core genes such as Hes1 and Notch1 as well as some of the TFs such as PPARs and FOXs were identified to construct coexpression networks of related pathways, the expression patterns of which had been validated by our following quantitative real-time PCR (qRT-PCR). The results of our study may help us better understand the molecular mechanisms of somitogenesis in mice at the genome-wide level.

The Role of Hypoxia and Cancer Stem Cells in Renal Cell Carcinoma Pathogenesis

The cancer stem cell (CSC) model has recently been approached also in renal cell carcinoma (RCC). A few populations of putative renal tumor-initiating cells (TICs) were identified, but they are indifferently understood; however, the first and most thoroughly investigated are CD105-positive CSCs. The article presents a detailed comparison of all renal CSC-like populations identified by now as well as their presumable origin. Hypoxic activation of hypoxia-inducible factors (HIFs) contributes to tumor aggressiveness by multiple molecular pathways, including the governance of immature stem cell-like phenotype and related epithelial-to-mesenchymal transition (EMT)/de-differentiation, and, as a result, poor prognosis. Due to intrinsic von Hippel-Lindau protein (pVHL) loss of function, clear-cell RCC (ccRCC) develops unique pathological intra-cellular pseudo-hypoxic phenotype with a constant HIF activation, regardless of oxygen level. Despite satisfactory evidence concerning pseudo-hypoxia importance in RCC biology, its influence on putative renal CSC-like largely remains unknown. Thus, the article discusses a current knowledge of HIF-1α/2α signaling pathways in the promotion of undifferentiated tumor phenotype in general, including some experimental findings specific for pseudo-hypoxic ccRCC, mostly dependent from HIF-2α oncogenic functions. Existing gaps in understanding both putative renal CSCs and their potential connection with hypoxia need to be filled in order to propose breakthrough strategies for RCC treatment.

Notch signalling pathway as an oncogenic factor involved in cancer development

Notch signalling is an evolutionarily conserved signalling pathway, which plays a significant role in a wide array of cellular processes including proliferation, differentiation, and apoptosis. Nevertheless, it must be noted that Notch is a binary cell fate determinant, and its overexpression has been described as oncogenic in a broad range of human malignancies. This finding led to interest in therapeutically targeting this pathway especially by the use of GSIs, which block the cleavage of Notch at the cell membrane and inhibit release of the transcriptionally active NotchIC subunit. Preclinical cancer models have clearly demonstrated that GSIs suppress the growth of such malignancies as pancreatic, breast, and lung cancer; however, GSI treatment in vivo is associated with side effects, especially those within the gastrointestinal tract. Although intensive studies are associated with the role of γ-secretase in pathological states, it should be pointed out that this complex impacts on proteolytic cleavages of around 55 membrane proteins. Therefore, it is clear that GSIs are highly non-specific and additional drugs must be designed, which will more specifically target components of the Notch signalling.