Nestin positively regulates the Wnt/β-catenin pathway and the proliferation, survival and invasiveness of breast cancer stem cells

Distribution, contribution and regulation of nestin+ cells

BACKGROUND

Nestin is an intermediate filament first reported in neuroepithelial stem cells. Nestin expression could be found in a variety of tissues throughout all systems of the body, especially during tissue development and tissue regeneration processes.

AIM OF REVIEW

This review aimed to summarize and discuss current studies on the distribution, contribution and regulation of nestin+ cells in different systems of the body, to discuss the feasibility ofusing nestin as a marker of multilineage stem/progenitor cells, and better understand the potential roles of nestin+ cells in tissue development, regeneration and pathological processes.

KEY SCIENTIFIC CONCEPTS OF REVIEW

This review highlights the potential of nestin as a marker of multilineage stem/progenitor cells, and as a key factor in tissue development and tissue regeneration. The article discussed the current findings, limitations, and potential clinical implications or applications of nestin+ cells. Additionally, it included the relationship of nestin+ cells to other cell populations. We propose potential future research directions to encourage further investigation in the field.

Cancer stem cells: a target for overcoming therapeutic resistance and relapse

Cancer stem cells (CSCs) are a small subset of cells in cancers that are thought to initiate tumorous transformation and promote metastasis, recurrence, and resistance to treatment. Growing evidence has revealed the existence of CSCs in various types of cancers and suggested that CSCs differentiate into diverse lineage cells that contribute to tumor progression. We may be able to overcome the limitations of cancer treatment with a comprehensive understanding of the biological features and mechanisms underlying therapeutic resistance in CSCs. This review provides an overview of the properties, biomarkers, and mechanisms of resistance shown by CSCs. Recent findings on metabolic features, especially fatty acid metabolism and ferroptosis in CSCs, are highlighted, along with promising targeting strategies. Targeting CSCs is a potential treatment plan to conquer cancer and prevent resistance and relapse in cancer treatment.

Natural products derived from medicinal plants and microbes might act as a game-changer in breast cancer: a comprehensive review of preclinical and clinical studies

Breast cancer (BC) is the most prevalent neoplasm among women. Genetic and environmental factors lead to BC development and on this basis, several preventive - screening and therapeutic interventions have been developed. Hormones, both in the form of endogenous hormonal signaling or hormonal contraceptives, play an important role in BC pathogenesis and progression. On top of these, breast microbiota includes both species with an immunomodulatory activity enhancing the host's response against cancer cells and species producing proinflammatory cytokines associated with BC development. Identification of novel multitargeted therapeutic agents with poly-pharmacological potential is a dire need to combat advanced and metastatic BC. A growing body of research has emphasized the potential of natural compounds derived from medicinal plants and microbial species as complementary BC treatment regimens, including dietary supplements and probiotics. In particular, extracts from plants such as Artemisia monosperma Delile, Origanum dayi Post, Urtica membranacea Poir. ex Savigny, Krameria lappacea (Dombey) Burdet & B.B. Simpson and metabolites extracted from microbes such as Deinococcus radiodurans and Streptomycetes strains as well as probiotics like Bacillus coagulans and Lactobacillus brevis MK05 have exhibited antitumor effects in the form of antiproliferative and cytotoxic activity, increase in tumors' chemosensitivity, antioxidant activity and modulation of BC - associated molecular pathways. Further, bioactive compounds like 3,3'-diindolylmethane, epigallocatechin gallate, genistein, rutin, resveratrol, lycopene, sulforaphane, silibinin, rosmarinic acid, and shikonin are of special interest for the researchers and clinicians because these natural agents have multimodal action and act via multiple ways in managing the BC and most of these agents are regularly available in our food and fruit diets. Evidence from clinical trials suggests that such products had major potential in enhancing the effectiveness of conventional antitumor agents and decreasing their side effects. We here provide a comprehensive review of the therapeutic effects and mechanistic underpinnings of medicinal plants and microbial metabolites in BC management. The future perspectives on the translation of these findings to the personalized treatment of BC are provided and discussed.

Signaling pathways governing the maintenance of breast cancer stem cells and their therapeutic implications

Breast cancer stem cells (BCSCs) represent a distinct subpopulation of cells with the ability to self-renewal and differentiate into phenotypically diverse tumor cells. The involvement of CSC in treatment resistance and cancer recurrence has been well established. Numerous studies have provided compelling evidence that the self-renewal ability of cancer stem cells is tightly regulated by specific signaling pathways, which exert critical roles to maintain an undifferentiated phenotype and prevent the differentiation of CSCs. Signaling pathways such as Wnt/β-catenin, NF-κB, Notch, Hedgehog, TGF-β, and Hippo have been implicated in the promotion of self-renewal of many normal and cancer stem cells. Given the pivotal role of BCSCs in driving breast cancer aggressiveness, targeting self-renewal signaling pathways holds promise as a viable therapeutic strategy for combating this disease. In this review, we will discuss the main signaling pathways involved in the maintenance of the self-renewal ability of BCSC, while also highlighting current strategies employed to disrupt the signaling molecules associated with stemness.

Stem cell markers: A guide to neoadjuvant therapy in breast carcinomas

Aim

This study aims to investigate potential associations between the stem cell population and the degree of tumor regression in breast carcinomas treated with neoadjuvant therapy.

Settings and Design

The study included 92 patients with breast carcinoma who received neoadjuvant therapy. Tumor regression was defined based on Miller and Payne grading system. Patients with grade 1 or 2 regression on a 5-point scale were included in group 1 (n = 37), grade 3 regression in group 2 (n = 32), and grade 4 or 5 regression in group 3 (n = 23).

Materials and Methods

Immunohistochemical staining was performed on paraffin block sections of every case using CD44, CD24, CD29, CD133, ID4, and ALDH1 antibodies to detect stem cells.

Statistical Analysis Used

IBM Statistical Package for the Social Sciences (SPSS), version 23.0 (IBM Corp., Armonk, NY, USA) software was used for statistical analyses, and a P value less than 0.05 was considered statistically significant.

Results

Histologically high-grade tumors are more common in the near-complete/complete response group (P = 0.004). HER2-positive tumors were more common in the complete/near-complete response group (P = 0.054). Tumor cells positive for stem cell markers CD44 and CD24 were more common in the poor response group (P = 0.027 and P = 0.001, respectively). CD29 expression was reduced in the posttreatment residual tumor tissue in the near-complete/complete response group.

Conclusion

High CD44 and CD24 expression may be a predictor of poor response/nonresponse to neoadjuvant therapy in breast carcinomas.

Background

In recent years, stem cells have been defined as the main cell population responsible for resistance to anticancer therapies.

Transcriptional factors targeting in cancer stem cells for tumor modulation

Cancer Stem Cells (CSCs) are now considered the primary "seeds" for the onset, development, metastasis, and recurrence of tumors. Despite therapeutic breakthroughs, cancer remains the leading cause of death worldwide. This is because the tumor microenvironment contains a key population of cells known as CSCs, which promote tumor aggression. CSCs are self-renewing cells that aid tumor recurrence by promoting tumor growth and persisting in patients after many traditional cancer treatments. According to reports, numerous transcription factors (TF) play a key role in maintaining CSC pluripotency and its self-renewal property. The understanding of the functions, structures, and interactional dynamics of these transcription factors with DNA has modified the hypothesis, paving the way for novel transcription factor-targeted therapies. These TFs, which are crucial and are required by cancer cells, play a vital function in the etiology of human cancer. Such CSC TFs will help with gene expression profiling, which provides crucial data for predicting the prognosis of patients. To overcome anti-cancer medication resistance and completely eradicate cancer, a potent therapy combining TFs-based CSC targets with traditional chemotherapy may be developed. In order to develop therapies that could eliminate CSCs, we here concentrated on the effect of TFs and other components of signalling pathways on cancer stemness.

Cancer Stem Cells: Biology and Therapeutic Implications

It is well recognized that most cancers derive and progress from transformation and clonal expansion of a single cell that possesses stem cell properties, i.e., self-renewal and multilineage differentiation capacities. Such cancer stem cells (CSCs) are usually present at very low frequencies and possess properties that make them key players in tumor development. Indeed, besides having the ability to initiate tumor growth, CSCs drive tumor progression and metastatic dissemination, are resistant to most cancer drugs, and are responsible for cancer relapse. All of these features make CSCs attractive targets for the development of more effective oncologic treatments. In the present review article, we have summarized recent advances in the biology of CSCs, including their identification through their immunophenotype, and their physiology, both in vivo and in vitro. We have also analyzed some molecular markers that might become targets for developing new therapies aiming at hampering CSCs regeneration and cancer relapse.

Cytoskeletal and Cytoskeleton-Associated Proteins: Key Regulators of Cancer Stem Cell Properties

Cancer stem cells (CSCs) are a subpopulation of cancer cells possessing stemness characteristics that are closely associated with tumor proliferation, recurrence and resistance to therapy. Recent studies have shown that different cytoskeletal components and remodeling processes have a profound impact on the behavior of CSCs. In this review, we outline the different cytoskeletal components regulating the properties of CSCs and discuss current and ongoing therapeutic strategies targeting the cytoskeleton. Given the many challenges currently faced in targeted cancer therapy, a deeper comprehension of the molecular events involved in the interaction of the cytoskeleton and CSCs will help us identify more effective therapeutic strategies to eliminate CSCs and ultimately improve patient survival.

Targeting ligand-dependent wnt pathway dysregulation in gastrointestinal cancers through porcupine inhibition

Gastrointestinal cancers are responsible for more cancer deaths than any other system of the body. This review summarises how Wnt pathway dysregulation contributes to the development of the most common gastrointestinal cancers, with a particular focus on the nature and frequency of upstream pathway aberrations. Tumors with upstream aberrations maintain a dependency on the presence of functional Wnt ligand, and are predicted to be tractable to inhibitors of Porcupine, an enzyme that plays a key role in Wnt secretion. We summarise available pre-clinical efficacy data from Porcupine inhibitors in vitro and in vivo, as well as potential toxicities and the data from early phase clinical trials. We appraise the rationale for biomarker-defined targeted approaches, as well as outlining future opportunities for combination with other therapeutics.

In silico analyses of Wnt1 nsSNPs reveal structurally destabilizing variants, altered interactions with Frizzled receptors and its deregulation in tumorigenesis

Wnt1 is the first mammalian Wnt gene, which is discovered as proto-oncogene and in human the gene is located on the chromosome 12q13. Mutations in Wnt1 are reported to be associated with various cancers and other human diseases. The structural and functional consequences of most of the non-synonymous SNPs (nsSNPs), present in the human Wnt1 gene, are not known. In the present work, extensive bioinformatics analyses are used to screen 292 nsSNPs of Wnt1 for predicting pathogenic and harmless polymorphisms. We have identified 10 highly deleterious nsSNPs among which 7 are located within the highly conserved areas. These 10 nsSNPs are also predicted to affect the post-translational modifications of Wnt1. Further, structure based stability analyses of these 10 highly deleterious nsSNPs revealed 8 variants as highly destabilizing. These 8 highly destabilizing variants were shown to have high BC score and high RMSIP score from normal mode analyses. Based on the deformation energies, obtained from the normal mode analyses, variants like G169A, G169S, G331R and G331S were found to be unstable. Molecular Dynamics (MD) simulations revealed structural stability and fluctuation of WT Wnt1 and its prioritized variants. RMSD remained fluctuating mostly between 4 and 5 Å and occasionally between 3.5 and 5.5 Å ranges. RMSF in the CTD region (residues 330–360) of the binding pocket were lower compared to that of WT. Studying the impacts of nsSNPs on the binding interface of Wnt1 and seven Frizzled receptors have predicted substitutions which can stabilize or destabilize the binding interface. We have found that Wnt1 and FZD8-CRD is the best docked complex in our study. MD simulation based analyses of wild type Wnt1-FZD8-CRD complex and the 8 prioritized variants revealed that RMSF was higher in the unstructured regions and RMSD remained fluctuating in the region of 5 Å ± 1 Å. We have also observed differential Wnt1 gene expression pattern in normal, tumor and metastatic conditions across different tissues. Wnt1 gene expression was significantly higher in metastatic tissues of lungs, colon and skin; and was significantly lower in metastatic tissues of breast, esophagus and kidney. We have also found that Wnt1 deregulation is associated with survival outcome in patients with gastric and breast cancer. Furthermore, these computationally screened highly deleterious nsSNPs of Wnt1 can be analyzed in population based genetic studies and may help understand the Wnt1 associated diseases.

Biomechanics of cancer stem cells

Cancer stem cells (CSCs) have been believed to be one driving force for tumor progression and drug resistance. Despite the significance of biochemical signaling in malignancy, highly malignant tumor cells or CSCs exhibit lower cellular stiffness than weakly malignant cells or non-CSCs, which are softer than their healthy counterparts, suggesting the inverse correlation between cell stiffness and malignancy. Recent years have witnessed the rapid accumulation of evidence illustrating the reciprocity between cell cytoskeleton/mechanics and CSC functions and the potential of cellular stiffness for specific targeting of CSCs. However, a systematic understanding of tumor cell mechanics and their role in CSCs and tumor progression is still lacking. The present review summarizes the recent progress in the alterations of tumor cell cytoskeleton and stiffness at different stages of tumor progression and recapitulates the relationship between cellular stiffness and CSC functions. The altered cell mechanics may mediate the mechanoadaptive responses that possibly empower CSCs to survive and thrive during metastasis. Furthermore, we highlight the possible impact of tumor cell mechanics on CSC malignancy, which may potentiate low cell stiffness as a mechanical marker for CSC targeting.

Breast Cancer Stem Cells: Signaling Pathways, Cellular Interactions, and Therapeutic Implications

Breast cancer stem cells (BCSCs) constitute a small population of cells within breast cancer and are characterized by their ability to self-renew, differentiate, and recapitulate the heterogeneity of the tumor. Clinically, BCSCs have been correlated with cancer progression, metastasis, relapse, and drug resistance. The tumorigenic roles of BCSCs have been extensively reviewed and will not be the major focus of the current review. Here, we aim to highlight how the crucial intrinsic signaling pathways regulate the fate of BCSCs, including the Wnt, Notch, Hedgehog, and NF-κB signaling pathways, as well as how different cell populations crosstalk with BCSCs within the TME, including adipocytes, endothelial cells, fibroblasts, and immune cells. Based on the molecular and cellular activities of BCSCs, we will also summarize the targeting strategies for BCSCs and related clinical trials. This review will highlight that BCSC development in breast cancer is impacted by both BCSC endogenous signaling and external factors in the TME, which provides an insight into how to establish a comprehensively therapeutic strategy to target BCSCs for breast cancer treatments.

Binding blockade between TLN1 and integrin β1 represses triple-negative breast cancer

Background:

Integrin family are known as key gears in focal adhesion for triple-negative breast cancer (TNBC) metastasis. However, the integrin independent factor TLN1 remains vague in TNBC.

Methods:

Bioinformatics analysis was performed based on TCGA database and Shengjing Hospital cohort. Western blot and RT-PCR were used to detect the expression of TLN1 and integrin pathway in cells. A small-molecule C67399 was screened for blocking TLN1 and integrin β1 through a novel computational screening approach by targeting the protein-protein binding interface. Drug pharmacodynamics were determined through xenograft assay.

Results:

Upregulation of TLN1 in TNBC samples correlates with metastasis and worse prognosis. Silencing TLN1 in TNBC cells significantly attenuated the migration of tumour cells through interfering the dynamic formation of focal adhesion with integrin β1, thus regulating FAK-AKT signal pathway and epithelial-mesenchymal transformation. Targeting the binding between TLN1 and integrin β1 by C67399 could repress metastasis of TNBC.

Conclusions:

TLN1 overexpression contributes to TNBC metastasis and C67399 targeting TLN1 may hold promise for TNBC treatment.

Funding:

This study was supported by grants from the National Natural Science Foundation of China (No. 81872159, 81902607, 81874301), Liaoning Colleges Innovative Talent Support Program (Name: Cancer Stem Cell Origin and Biological Behaviour), Outstanding Scientific Fund of Shengjing Hospital (201803), and Outstanding Young Scholars of Liaoning Province (2019-YQ-10).

MUC1 is a potential target to overcome trastuzumab resistance in breast cancer therapy

Although resistance is its major obstacle in cancer therapy, trastuzumab is the most successful agent in treating epidermal growth factor receptor 2 positive (HER2 +) breast cancer (BC). Some patients show resistance to trastuzumab, and scientists want to circumvent this problem. This review elaborately discusses possible resistance mechanisms to trastuzumab and introduces mucin 1 (MUC1) as a potential target efficient for overcoming such resistance. MUC1 belongs to the mucin family, playing the oncogenic/mitogenic roles in cancer cells and interacting with several other oncogenic receptors and pathways, such as HER2, β-catenin, NF-κB, and estrogen receptor (ERα). Besides, it has been established that MUC1- Cytoplasmic Domain (MUC1-CD) accelerates the development of resistance to trastuzumab and that silencing MUC1-C proto-oncogene is associated with increased sensitivity of HER2⁺ cells to trastuzumab-induced growth inhibitors. We mention why targeting MUC1 can be useful in overcoming trastuzumab resistance in cancer therapy.

Inhibition of β-catenin dependent WNT signalling upregulates the transcriptional repressor NR0B1 and downregulates markers of an A9 phenotype in human embryonic stem cell-derived dopaminergic neurons: Implications for Parkinson's disease

In this study we investigate how β-catenin-dependent WNT signalling impacts midbrain dopaminergic neuron (mDA) specification. mDA cultures at day 65 of differentiation responded to 25 days of the tankyrase inhibitor XAV969 (XAV, 100nM) with reduced expression of markers of an A9 mDA phenotype (KCNJ6, ALDH1A1 and TH) but increased expression of the transcriptional repressors NR0B1 and NR0B2. Overexpression of NR0B1 and or NR0B2 promoted a loss of A9 dopaminergic neuron phenotype markers (KCNJ6, ALDH1A1 and TH). Overexpression of NR0B1, but not NR0B2 promoted a reduction in expression of the β-catenin-dependent WNT signalling pathway activator RSPO2. Analysis of Parkinson’s disease (PD) transcriptomic databases shows a profound PD-associated elevation of NR0B1 as well as reduced transcript for RSPO2. We conclude that reduced β-catenin-dependent WNT signalling impacts dopaminergic neuron identity, in vitro, through increased expression of the transcriptional repressor, NR0B1. We also speculate that dopaminergic neuron regulatory mechanisms may be perturbed in PD and that this may have an impact upon both existing nigral neurons and also neural progenitors transplanted as PD therapy.

Nestin-Expressing Cells in the Lung: The Bad and the Good Parts

Nestin is a member of the intermediate filament family, which is expressed in a variety of stem or progenitor cells as well as in several types of malignancies. Nestin might be involved in tissue homeostasis or repair, but its expression has also been associated with processes that lead to a poor prognosis in various types of cancer. In this article, we review the literature related to the effect of nestin expression in the lung. According to most of the reports in the literature, nestin expression in lung cancer leads to an aggressive phenotype and resistance to chemotherapy as well as radiation treatments due to the upregulation of phenomena such as cell proliferation, angiogenesis, and metastasis. Furthermore, nestin may be involved in the pathogenesis of some non-cancer-related lung diseases. On the other hand, evidence also indicates that nestin-positive cells may have a role in lung homeostasis and be capable of generating various types of lung tissues. More research is necessary to establish the true value of nestin expression as a prognostic factor and therapeutic target in lung cancer in addition to its usefulness in therapeutic approaches for pulmonary diseases.

Cancer chemoprevention through Frizzled receptors and EMT

Frizzled (FZD) transmembrane receptors are well known for their role in β-catenin signaling and development and now understanding of their role in the context of cancer is growing. FZDs are often associated with the process of epithelial to mesenchymal transition (EMT) through β-catenin, but some also influence EMT through non-canonical pathways. With ten different FZDs, there is a wide range of activity from oncogenic to tumor suppressive depending on the tissue context. Alterations in FZD signaling can occur during development of premalignant lesions, supporting their potential as targets of chemoprevention agents. Agonizing or antagonizing FZD activity may affect EMT, which is a key process in lesion progression often targeted by chemoprevention agents. Recent studies identified a specific FZD as important for activity of an EMT inhibiting chemopreventive agent and other studies have highlighted the previously unrecognized potential for targeting small molecules to FZD receptors. This work demonstrates the value of investigating FZDs in chemoprevention and here we provide a review of FZDs in cancer EMT and their potential as chemoprevention targets.

The multidimensional role of the Wnt/β-catenin signaling pathway in human malignancies

Several signaling pathways have been identified as important for developmental processes. One of such important cascades is the Wnt/β-catenin signaling pathway, which can regulate various physiological processes such as embryonic development, tissue homeostasis, and tissue regeneration; while its dysregulation is implicated in several pathological conditions especially cancers. Interestingly, deregulation of the Wnt/β-catenin pathway has been reported to be closely associated with initiation, progression, metastasis, maintenance of cancer stem cells, and drug resistance in human malignancies. Moreover, several genetic and experimental models support the inhibition of the Wnt/β-catenin pathway to answer the key issues related to cancer development. The present review focuses on different regulators of Wnt pathway and how distinct mutations, deletion, and amplification in these regulators could possibly play an essential role in the development of several cancers such as colorectal, melanoma, breast, lung, and leukemia. Additionally, we also provide insights on diverse classes of inhibitors of the Wnt/β-catenin pathway, which are currently in preclinical and clinical trial against different cancers.

Signaling pathways governing breast cancer stem cells behavior

Breast cancer is the second common cancer and the leading cause of malignancy among females overall. Breast cancer stem cells (BCSCs) are a small population of breast cancer cells that play a critical role in the metastasis of breast cancer to other organs in the body. BCSCs have both self-renewal and differentiation capacities, which are thought to contribute to the aggressiveness of metastatic lesions. Therefore, targeting BCSCs can be a suitable approach for the treatment and metastasis of breast cancer. Growing evidence has indicated that the Wnt, NFκB, Notch, BMP2, STAT3, and hedgehog (Hh) signaling pathways govern epithelial-to-mesenchymal transition (EMT) activation, growth, and tumorigenesis of BCSCs in the primary regions. miRNAs as the central regulatory molecules also play critical roles in BCSC self-renewal, metastasis, and drug resistance. Hence, targeting these pathways might be a novel therapeutic approach for breast cancer diagnosis and therapy. This review discusses known signaling mechanisms involved in the stimulation or prevention of BCSC self-renewal, metastasis, and tumorigenesis.

LncRNAs and microRNAs as Essential Regulators of Stemness in Breast Cancer Stem Cells

Breast cancer is an aggressive disease with a high incidence in women worldwide. Two decades ago, a controversial hypothesis was proposed that cancer arises from a subpopulation of “tumor initiating cells” or “cancer stem cells-like” (CSC). Today, CSC are defined as small subset of somatic cancer cells within a tumor with self-renewal properties driven by the aberrant expression of genes involved in the maintenance of a stemness-like phenotype. The understanding of the underlying cellular and molecular mechanisms involved in the maintenance of CSC subpopulation are fundamental in the development and persistence of breast cancer. Nowadays, the hypothesis suggests that genetic and epigenetic alterations give rise to breast cancer stem cells (bCSC), which are responsible for self-renewal, tumor growth, chemoresistance, poor prognosis and low survival in patients. However, the prominence of bCSC, as well as the molecular mechanisms that regulates and promotes the malignant phenotypes, are still poorly understood. The role of non-coding RNAs (ncRNAs), such as long non-coding RNAs (lncRNAs) and microRNAs (miRNAs) acting as oncogenes or tumor suppressor genes has been recently highlighted by a plethora of studies in breast cancer. These ncRNAs positively or negatively impact on different signaling pathways that govern the cancer hallmarks associated with bCSC, making them attractive targets for therapy. In this review, we present a current summary of the studies on the pivotal roles of lncRNAs and microRNAs in the regulation of genes associated to stemness of bCSC.

Nestin Promotes Peritoneal Fibrosis by Protecting HIF1-α From Proteasomal Degradation

Background

Peritoneal dialysis (PD) is a treatment for end stage renal disease patients, but it can also cause peritoneal fibrosis. Nestin is known as a neural stem cell marker and it has many functions. The hypoxia induced factor (HIF) signaling pathway can be activated under hypoxia conditions, leading to the overexpression of some angiogenesis related genes. The aim of our study is to demonstrate Nestin’s role in the development of peritoneal fibrosis (PF), and to provide a new target (Nestin) to treat PF.

Methods

PD mice models were constructed by an intraperitoneal administration of PDS at 10 ml/100g/d for 4 weeks. Nestin-positive cells were isolated from peritonea of Nestin-GFP mice by flow cytometry. The relationship of Nestin and HIF1-α-VEGFA pathway was detected by Nestin knockdown, Co-immunoprecipitation and immunofluorescence. Also, proteasomal activity was demonstrated by CHX and MG132 application, followed by Western blotting and Co-immunoprecipitation.

Results

In our experiments, we found that Nestin expression resulted in PF. Also, HIF1-α/VEGFA pathway was activated in PF. Nestin knockdown reduced the level of HIF1-α. Nestin directly bound to HIF1-α and protected HIF1-α from proteasomal degradation. Overexpression of HIF1-α reverts the fibrosis levels in Nestin-knockdown cells. In brief, Nestin inhibited the degradation of HIF1-α by mitigating its ubiquitination level, leading to the activation of HIF1-α signaling pathway, and eventually promoted PF.

Conclusion

We found a novel mechanism of PF that Nestin promotes by protecting HIF1-α from proteasomal degradation. Taken together, our key findings highlight a novel mechanism by which the silencing of Nestin hinders HIF1- α -induced PF.

Targeting the Wnt/β-catenin signaling pathway in cancer

The aberrant Wnt/β-catenin signaling pathway facilitates cancer stem cell renewal, cell proliferation and differentiation, thus exerting crucial roles in tumorigenesis and therapy response. Accumulated investigations highlight the therapeutic potential of agents targeting Wnt/β-catenin signaling in cancer. Wnt ligand/ receptor interface, β-catenin destruction complex and TCF/β-catenin transcription complex are key components of the cascade and have been targeted with interventions in preclinical and clinical evaluations. This scoping review aims at outlining the latest progress on the current approaches and perspectives of Wnt/β-catenin signaling pathway targeted therapy in various cancer types. Better understanding of the updates on the inhibitors, antagonists and activators of Wnt/β-catenin pathway rationalizes innovative strategies for personalized cancer treatment. Further investigations are warranted to confirm precise and secure targeted agents and achieve optimal use with clinical benefits in malignant diseases.

Wnt signaling in breast cancer: biological mechanisms, challenges and opportunities

Wnt signaling is a highly conserved signaling pathway that plays a critical role in controlling embryonic and organ development, as well as cancer progression. Genome-wide sequencing and gene expression profile analyses have demonstrated that Wnt signaling is involved mainly in the processes of breast cancer proliferation and metastasis. The most recent studies have indicated that Wnt signaling is also crucial in breast cancer immune microenvironment regulation, stemness maintenance, therapeutic resistance, phenotype shaping, etc. Wnt/β-Catenin, Wnt-planar cell polarity (PCP), and Wnt-Ca2+ signaling are three well-established Wnt signaling pathways that share overlapping components and play different roles in breast cancer progression. In this review, we summarize the main findings concerning the relationship between Wnt signaling and breast cancer and provide an overview of existing mechanisms, challenges, and potential opportunities for advancing the therapy and diagnosis of breast cancer.

Cytoskeletal Remodeling in Cancer

Simple Summary

Cell migration is an essential process from embryogenesis to cell death. This is tightly regulated by numerous proteins that help in proper functioning of the cell. In diseases like cancer, this process is deregulated and helps in the dissemination of tumor cells from the primary site to secondary sites initiating the process of metastasis. For metastasis to be efficient, cytoskeletal components like actin, myosin, and intermediate filaments and their associated proteins should co-ordinate in an orderly fashion leading to the formation of many cellular protrusions-like lamellipodia and filopodia and invadopodia. Knowledge of this process is the key to control metastasis of cancer cells that leads to death in 90% of the patients. The focus of this review is giving an overall understanding of these process, concentrating on the changes in protein association and regulation and how the tumor cells use it to their advantage. Since the expression of cytoskeletal proteins can be directly related to the degree of malignancy, knowledge about these proteins will provide powerful tools to improve both cancer prognosis and treatment.

Abstract

Successful metastasis depends on cell invasion, migration, host immune escape, extravasation, and angiogenesis. The process of cell invasion and migration relies on the dynamic changes taking place in the cytoskeletal components; actin, tubulin and intermediate filaments. This is possible due to the plasticity of the cytoskeleton and coordinated action of all the three, is crucial for the process of metastasis from the primary site. Changes in cellular architecture by internal clues will affect the cell functions leading to the formation of different protrusions like lamellipodia, filopodia, and invadopodia that help in cell migration eventually leading to metastasis, which is life threatening than the formation of neoplasms. Understanding the signaling mechanisms involved, will give a better insight of the changes during metastasis, which will eventually help targeting proteins for treatment resulting in reduced mortality and longer survival.

Icariin-induced inhibition of SIRT6/NF-κB triggers redox mediated apoptosis and enhances anti-tumor immunity in triple-negative breast cancer

Abnormal activation of the nuclear factor‐kappa B (NF‐κB) signaling pathway is closely implicated in triple‐negative breast cancer growth, metastasis, and tumor immune escape. In this study, the anti‐cancer effects of icariin, a natural flavonol glycoside, toward breast cancer cells and the underlying mechanisms were investigated. This investigation showed that icariin selectively inhibited proliferation and triggered apoptosis in breast cancer cells in a concentration‐ and time‐dependent manner, but exhibited little cytotoxicity in normal breast cells. Moreover, icariin induced cell apoptosis via a mitochondria‐mediated pathway, as indicated by the upregulated ratio of Bax/Bcl‐2 and reactive oxygen species induction. Importantly, icariin impaired the activation of the NF‐κB/EMT pathway, as evidenced by upregulation of SIRT6, resulting in inhibition of migration and invasion of breast cancer cells. Additionally, oss‐128167, an inhibitor of SIRT6, dramatically attenuated anti‐migration and anti‐invasion effects of icariin. Transcriptomic analysis verified that impairment of NF‐κB led to the selective function of icariin in breast cancer cells. Notably, icariin exhibited a significant tumor growth inhibition and anti‐pulmonary metastasis effect in a tumor mouse model of MDA‐MB‐231 and 4T1 cells by regulating the tumor immunosuppressive microenvironment. Together, these results showed that icariin could effectively trigger apoptosis and inhibit the migration of breast cancer cells via the SIRT6/NF‐κB signaling pathway, suggesting that icariin might serve as a potential candidate drug for the treatment of breast cancer.

Nestin represents a potential marker of pulmonary vascular remodeling in pulmonary arterial hypertension associated with congenital heart disease

OBJECTIVE

Reportedly, nestin was re-expressed in proliferative synthetic-type pulmonary artery smooth muscle cells (PASMCs) and obligatory for PASMC proliferation in pulmonary arterial hypertension (PAH). Accordingly, nestin is increased in pulmonary vascular lesions of congenital heart disease (CHD)-associated PAH patients. We tested the hypothesis whether nestin was re-expressed in proliferative synthetic-type PASMCs and associated with pulmonary vascular remodeling in CHD-PAH.

MATERIALS AND METHODS

Nestin expression was tested using lung tissues from CHD-PAH patients and monocrotaline (MCT) plus aortocaval (AV) shunt-induced PAH rats, human PASMCs (HPASMCs), and pulmonary artery endothelial cells (PAECs) and PASMCs from MCT-AV-induced PAH rats. The role and possible mechanism of nestin on HPASMC proliferation, apoptosis, cell cycle and migration were investigated by assays of CCK-8, EdU, TUNEL, flow cytometry, transwell chamber and immunoblotting assays.

RESULTS

Nestin was solely expressed in proliferative synthetic-type PASMCs, but rarely detected in PAECs. Nestin was barely detected in normal pulmonary arterioles and occlusive pulmonary vascular lesions. Its expression was robustly increased in developing pulmonary vasculature, but returned to normal levels at the late stage of pulmonary vascular remodeling in lung tissues from CHD-PAH patients and MCT-AV-induced PAH rats. Besides, nestin peaks were consistent with the histological features in lung tissues of MCT-AV-induced PAH rats. Moreover, nestin overexpression effectively promoted HPASMC phenotypic transformation, proliferation, apoptosis resistance and migration via enhancing Wnt/β-catenin activation.

CONCLUSIONS

These data indicated that nestin was re-expressed in proliferative synthetic-type PASMCs and might represent a potential marker of pulmonary vascular remodeling in CHD-PAH.

Circ-GLI1 promotes metastasis in melanoma through interacting with p70S6K2 to activate Hedgehog/GLI1 and Wnt/β-catenin pathways and upregulate Cyr61

Circular RNAs (circRNAs) are emerging regulators in the development of human cancers. However, the role of circRNAs in melanoma is poorly understood. Microarray analysis and qRT-PCR was applied to screen out circRNAs that were differentially expressed in melanoma cells compared to normal cells. Currently, we first proved that inhibition of CYR61, an angiogenesis factor with controversial functions in melanoma, restrained cell migration, invasion and angiogenesis in melanoma. Thereafter, a novel circRNA hsa_circ_0027247 derived from GLI1 (circ-GLI1) was identified to positively modulate CYR61 expression in melanoma cell lines. Besides, silencing circ-GLI1 hindered melanoma cell metastasis as well. Interestingly, we unveiled that circ-GLI1 enhanced CYR61 transcription by an indirect manner. Meanwhile, circ-GLI1 activated Hedgehog/GLI1 and Wnt/β-catenin pathways by affecting the degradation of GLI1 and β-catenin. Moreover, we found that circ-GLI1 interacted with p70S6K2 to induce GSK3β phosphorylation at Ser9, and therefore blocked the binding of GSK3β with GLI1 and β-catenin so as to elevate their protein expression. Of note, CYR61 was transcriptionally activated by MYC, a well-recognized downstream target of both GLI1 and β-catenin. In conclusion, circ-GLI1 exacerbates the metastasis and angiogenesis of melanoma by upregulating Cyr61 via p70S6K2-dependent activation of Hedgehog/GLI1 and Wnt/β-catenin pathways.

Clinicopathological and prognostic significance of nestin expression in patients with breast cancer: a systematic review and meta-analysis

Background

Nestin has been revealed to promote tumorigenesis, progression, metastasis, and angiogenesis of breast cancer. Although the prognostic and clinicopathological impact of nestin expression on breast cancer patients has been assessed in several independent studies, their results remained conflicting. Therefore, we performed this meta-analysis to elucidate the prognostic and clinicopathological association of nestin expression with breast cancer.

Methods

A comprehensive literature search was performed in the electronic databases PubMed, EMBASE, Web of Science, the Cochrane Library, China National Knowledge Infrastructure (CNKI), and the Wangfang Data. The statistical analysis was conducted using Stata 15.0 and Review Manager 5.3.

Results

A total of 15 studies with 6066 breast cancer patients were included in this meta-analysis. Pooled results indicated that positive expression of nestin was significantly associated with reduced breast cancer-specific survival (BCSS, univariate analysis, HR = 2.11, 95% CI [1.79, 2.49], P < 0.00001; multivariate analysis, HR = 1.30, 95% CI [1.06, 1.60], P = 0.01), worse overall survival (OS, univariate analysis, HR = 1.88, 95% CI [1.31, 2.71], P = 0.0007; multivariate analysis, HR = 1.89, 95% CI [1.34, 2.67], P = 0.0003) and poorer recurrence-free survival (univariate analysis, HR = 2.60, 95% CI [1.52, 4.46], P = 0.0005), but not with distant metastasis-free survival in univariate analysis (P > 0.05). In addition, increased nestin expression was correlated with younger age, higher tumor grade, larger tumor size, positive blood vessel invasion and high vascular proliferation index, but not with lymph node metastasis or lymph vessel invasion. Nestin was preferentially expressed in invasive ductal carcinoma, triple-negative breast cancer and basal-like subtypes. Nestin expression was inversely associated with the expression of ER and PR, but not with HER-2. Conversely, nestin expression was positively correlated with the expression of basal-like markers CK5, P-cadherin and EGFR. Moreover, nestin expression was strongly associated with the presence of five basal-like profiles (BLP1-5).

Conclusions

This meta-analysis revealed the prognostic value and clinicopathological significance of nestin expression in breast cancer. Nestin is an independent prognostic factor for worse BCSS and OS of breast cancer patients. Nestin is also a valuable biomarker for unfavorable clinicopathological features and tumor angiogenesis of breast cancer. Therefore, nestin is a promising therapeutic target for malignant breast cancer, especially for TNBC and basal-like phenotype.

Hinokiflavone induces apoptosis and inhibits migration of breast cancer cells via EMT signalling pathway

Hinokiflavone is a natural product, isolated from Selaginella P. Beauv, Juniperus phoenicea and Rhus succedanea. Even though hinokiflavone was reported to possess cytotoxicity to many cancer cells, and has potential in cancer treatment, the anti‐proliferation and anti‐metastasis efficacy of hinokiflavone on human breast cancer cells has not a further research. In this study, we investigated the anti‐cancer activity of hinokiflavone in human breast cancer cells in vitro and in vivo. Hinokiflavone exhibited a time‐ and dose‐dependent manner apoptosis induction by upregulating expression of Bax and downregulating Bcl‐2 in breast cancer cells. Furthermore, hinokiflavone significantly inhibited the migration and invasion of breast cancer cells by impairing the process of epithelial‐to‐mesenchymal transition. In addition, the tumour growth was distinctly inhibited by treatment of hinokiflavone in a xenograft tumour mouse model of MDA‐MB‐231 cells. Immunohistochemical analysis of tumour sections showed that MMP‐2⁺ cells and Ki‐67⁺ cells were remarkably decreased in tumour tissues of mice after treatment of hinokiflavone, indicating that hinokiflavone inhibits not only proliferation but also metastasis of breast cancer cells. Our study suggested that hinokiflavone can be a potential drug to breast cancer.

Significance of the study

Hinokiflavone significantly inhibited proliferation and induced apoptosis in breast cancer cells. In addition, hinokiflavone remarkably inhibited migration and invasion of breast cancer cells via EMT signalling pathway. It is worth noting that hinokiflavone possesses anti‐tumour effect in tumour mouse xenograft model of breast cancer. Overall, our results indicated that hinokiflavone may be a potential anticancer drug for breast cancer treatment.

Self-Renewal Signalling Pathway Inhibitors: Perspectives on Therapeutic Approaches for Cancer Stem Cells

The poor survival and prognosis of individuals with cancer are often attributed to tumour relapse and metastasis, which may be due to the presence of cancer stem cells (CSCs). CSCs have the characteristics of self-renewal, differentiation potential, high carcinogenicity, and drug resistance. In addition, CSCs exhibit many characteristics similar to those of embryonic or tissue stem cells while displaying persistent abnormal activation of self-renewal pathways associated with development and tissue homeostasis, including the Wnt, Notch, Hedgehog (Hh), TGF-β, JAK/STAT3, and NF-κB pathways. Therefore, we can eliminate CSCs by targeting these self-renewal pathways to constrain stem cell replication, survival and differentiation. At the same time, we cannot neglect the ping-pong effect of the tumour microenvironment, which releases cytokines and promotes self-renewal pathways in CSCs. Recently, meaningful progress has been made in the study of inhibitors of self-renewal pathways in tumours. This review primarily summarizes several representative and novel agents targeting these self-renewal signalling pathways and the tumour microenvironment and that represent a promising strategy for treating refractory and recurrent cancer.

Belinostat suppresses cell proliferation by inactivating Wnt/β-catenin pathway and promotes apoptosis through regulating PKC pathway in breast cancer

Belinostat is a histone deacetylase inhibitor drug capable of regulating cell growth in diverse cancers. Nonetheless, little information clarified the role of Belinostat in breast cancer. Hence, the functions of Belinostat in breast cancer cells survival was disclosed in this study. Belinostat at 50 and 100 μM were applied to manage MCF-7 cells, cell viability, Ki67 positive cells, cell cycle and apoptosis were monitored via MTT, immunohistochemistry and flow cytometry. Furthermore, the apoptosis-related factors, Wnt/β-catenin pathway and PKC pathway were tested through western blot and qRT-PCR. Lastly, in vivo effect of Belinostat was determined by a murine model. The results showed that Belinostat dampened cell viability, decreased the proportion of Ki67 positive cells and arrested cells at G0/G1 phase. The decreases of Wnt/β-catenin, CCND2 and Myc were observed in MCF-7 cells after Belinostat stimulation. Additionally, Belinostat induced cell apoptosis, meanwhile dampened Bcl-2 and raised Bax and Cleaved caspase 3 in a dose and time-dependent manner. Additionally, Belinostat activated PKC pathway by upgrading PKCδ and P53 expressions. Furthermore, Belinostat restrained tumour weight and volume in vivo. In summary, this study depicted that Belinostat prohibited proliferation and evoked apoptosis via mediating Wnt/β-catenin and PKC pathways in MCF-7 cells.

TRIM11 promotes lymphomas by activating the β-catenin signaling and Axin1 ubiquitination degradation

OBJECTIVE

Lymphoma, a malignant tumor, is mainly characterized by painless lymph node enlargement and hepatosplenomegaly. At present, lymphoma is mainly treated by radiation, chemical drugs, bone marrow transplantation and surgery. However, due to the high degree of heterogeneity, lymphomas are highly different in terms of treatment intensity and prognosis. This study is designed to investigate the function of tripartite motif-containing 11 (TRIM11) in lymphomas.

METHODS

The expression of TRIM11 in lymphoma tissues and multiple lymphoma cell lines was respectively detected by microarray immunohistochemistry, real-time PCR and Western blotting. After TRIM11 knockdown, overexpression, or β-catenin inhibitor XAV939 treatment, proliferation, apoptosis and cell cycle progression, as well as expression of related-genes were detected. Next, Co-Immunoprecipitation (Co-IP) and ubiquitination detection were performed.

RESULTS

Elevated expression of tripartite motif-containing 11 (TRIM11) was observed in lymphoma tissues and multiple lymphoma cell lines (Raji, Jurkat, U937 and Hut78). Knockdown of TRIM11 in lymphoma cells significantly suppressed cell proliferation and prevented cell cycle progression from entering S or G2 phase. Concurrently, the expression of β-catenin, Cyclin D1 and c-Myc proteins in TRIM11-silenced lymphoma cells was decreased, while Axin1 was increased. In addition, TRIM11 overexpression had an opposite effect to TRIM11 knockdown, and a β-catenin inhibitor, XAV939, potently attenuated the induction of TRIM11 on lymphoma cells. Co-IP assay showed the interaction of TRIM11 and Axin1, and TRIM11 knockdown inhibited Axin1 ubiquitination degradation.

CONCLUSIONS

Together all, the results suggested that TRIM11 may be an oncogene in lymphomas, which involving the activation of the β-catenin signaling and the ubiquitination degradation of Axin1.

PPARα agonist alleviates tumor growth and chemo-resistance associated with the inhibition of glucose metabolic pathway

As a nuclear receptor, peroxisome-proliferator-activated receptor α (PPARα) plays a critical role in regulation of metabolism and cancer, while the effect of PPARα agonist on cancer cell glucose metabolism-linked tumor growth is still unclear. Here we found that PPARα agonist (Wy14,643) decreased Glut1 (Glucose transporter 1) gene and protein expressions of colorectal cancer cell lines in response to normoxia or hypoxia. Dual-luciferase analysis showed that Wy14,643 inhibited Glut1 transcription activity. Importantly, ChIP-qPCR analysis showed that Wy14,643 increased the binding of PPARα to Glut1 promoter region. Wy14,643 suppressed Glut1 transcription activity resulting in reduced influx of glucose in cancer cells in response to normoxia or hypoxia. Further analysis showed that Wy14,643-mediated inhibition of tumor growth and chemo-resistance was associated with inhibition of mTOR pathway. Taken together, PPARα agonist Wy14,643 suppressed Glut1 transcription activity, glucose uptake and mTOR pathway in colorectal cancer cells, which was involved in reduced tumor growth and chemo-resistance. These findings provided a novel therapy strategy for cancer progression.

Integrative analysis of clinical and bioinformatics databases to identify anticancer properties of digoxin

Cardiac glycosides, such as digoxin, inhibit Na⁺/K⁺-ATPases and cause secondary activation of Na⁺/Ca²⁺ exchangers. Preclinical investigations have suggested that digoxin may have anticancer properties. In order to clarify the functional mechanisms of digoxin in cancer, we performed an integrative analysis of clinical and bioinformatics databases. The US Food and Drug Administration Adverse Event Reporting System and the Japan Medical Data Center claims database were used as clinical databases to evaluate reporting odds ratios and adjusted sequence ratios, respectively. The BaseSpace Correlation Engine and Connectivity Map bioinformatics databases were used to investigate molecular pathways related to digoxin anticancer mechanisms. Clinical database analyses suggested an inverse association between digoxin and four cancers: gastric, colon, prostate and haematological malignancy. The bioinformatics database analysis suggested digoxin may exert an anticancer effect via peroxisome proliferator-activated receptor α and apoptotic caspase cascade pathways. Our integrative analysis revealed the possibility of digoxin as a drug repositioning candidate for cancers.

Expression Pattern of the Cancer Stem Cell Marker "Nestin" in Leukoplakia and Oral Squamous Cell Carcinoma

OBJECTIVE

The aim of the present study was to determine and compare the expression pattern and localization of nestin, in an attempt to explore its role in oral carcinogenesis.

METHODS

Western blot and immunohistochemistry analysis were performed to study the expression pattern of nestin in normal mucosa, leukoplakia, and oral squamous cell carcinoma samples. Nestin expression was evaluated in the keratinocytes and blood vessels of all the samples and compared with various clinico-pathological parameters.

RESULTS

Nestin expression was increased in samples of leukoplakia and oral squamous cell carcinoma when compared with normal mucosa. Among leukoplakia samples, the expression was increased in cases without dysplasia compared to cases with dysplastic features. In cases of oral squamous cell carcinoma, the expression of nestin was found to be decreased with the loss of differentiation. Neoangiogenesis status determined by nestin expression showed an increasing expression from normal mucosa through leukoplakia, to oral squamous cell carcinoma.

CONCLUSION

This study has two major findings: (1) identification of nestin as an effective indicator of neoangiogenesis, and (2) nestin may be used as a marker in predicting the early changes in oral carcinogenesis.

GSK-3 modulates SHH-driven proliferation in postnatal cerebellar neurogenesis and medulloblastoma

Cerebellar development requires regulated proliferation of cerebellar granule neuron progenitors (CGNPs). Inadequate CGNP proliferation causes cerebellar hypoplasia whereas excessive CGNP proliferation can cause medulloblastoma, the most common malignant pediatric brain tumor. Although sonic hedgehog (SHH) signaling is known to activate CGNP proliferation, the mechanisms downregulating proliferation are less defined. We investigated CGNP regulation by GSK-3, which downregulates proliferation in the forebrain, gut and breast by suppressing mitogenic WNT signaling in mouse. In striking contrast to these systems, we found that co-deleting Gsk3a and Gsk3b blocked CGNP proliferation, causing severe cerebellar hypoplasia. The GSK-3 inhibitor CHIR-98014 similarly downregulated SHH-driven proliferation. Transcriptomic analysis showed activated WNT signaling and upregulated Cdkn1a in Gsk3a/b -deleted CGNPs. Ctnnb co-deletion increased CGNP proliferation and rescued cerebellar hypoproliferation in Gsk3a/b mutants, demonstrating physiological control of CGNPs by GSK-3, mediated through WNT. SHH-driven medulloblastomas similarly required GSK-3, as co-deleting Gsk3a/b blocked tumor growth in medulloblastoma-prone SmoM2 mice. These data show that a GSK-3/WNT axis modulates the developmental proliferation of CGNPs and the pathological growth of SHH-driven medulloblastoma. The requirement for GSK-3 in SHH-driven proliferation suggests that GSK-3 may be targeted for SHH-driven medulloblastoma therapy.

Application of in vivo MR methods in the study of breast cancer metabolism

In the last two decades, various in vivo MR methodologies have been evaluated for their potential in the study of cancer metabolism. During malignant transformation, metabolic alterations occur, leading to morphological and functional changes. Among various MR methods, in vivo MRS has been extensively used in breast cancer to study the metabolism of cells, tissues or whole organs. It provides biochemical information at the metabolite level. Altered choline, phospholipid and energy metabolism has been documented using proton (¹ H), phosphorus (³¹ P) and carbon (¹³ C) isotopes. Increased levels of choline-containing compounds, phosphomonoesters and phosphodiesters in breast cancer, which are indicative of altered choline and phospholipid metabolism, have been reported using in vivo, in vitro and ex vivo NMR studies. These changes are reversed on successful therapy, which depends on the treatment regimen given. Monitoring the various tumor intermediary metabolic pathways using nuclear spin hyperpolarization of ¹³ C-labeled substrates by dynamic nuclear polarization has also been recently reported. Furthermore, the utility of various methods such as diffusion, dynamic contrast and perfusion MRI have also been evaluated to study breast tumor metabolism. Parameters such as tumor volume, apparent diffusion coefficient, volume transfer coefficient and extracellular volume ratio are estimated. These parameters provide information on the changes in tumor microstructure, microenvironment, abnormal vasculature, permeability and grade of the tumor. Such changes seen during cancer progression are due to alterations in the tumor metabolism, leading to changes in cell architecture. Due to architectural changes, the tissue mechanical properties are altered; this can be studied using magnetic resonance elastography, which measures the elastic properties of tissues. Moreover, these structural MRI methods can be used to investigate the effect of therapy-induced changes in tumor characteristics. This review discusses the potential of various in vivo MR methodologies in the study of breast cancer metabolism.

EMT-related protein expression in polyploid giant cancer cells and their daughter cells with different passages after triptolide treatment

Our previous work has demonstrated that paclitaxel can induce the formation of polyploid giant cancer cells (PGCCs) and inhibit tumor growth by reprogramming ovarian cancer epithelial cells to a benign fibroblastic state via epithelial-mesenchymal transition. Here, triptolide (TPL) was used to treat the breast and ovarian cancer lines. The morphologic characteristics and EMT-related protein expression were studied in different generation of cancer cells after TPL treatment. When BT-549 and HEY cells reached 80-90% confluence, TPL was added to BT-549 for 48 h and HEY for 9 h at a concentration of 40 ng/ml. Scattered PGCCs survived from TPL treatment and generated daughter cells, and then were cultured in medium without TPL for at least ten generation. Western blot analysis and immunocytochemical staining were performed to detect the expression levels and subcellular location of EMT-related proteins in control cells and different generation of TPL-induced PGCCs with daughter cells. Furthermore, wound-healing, transwell, cell counting kit-8, and MTT assay were used to compare the alternation of migration, invasion, and proliferation among control cells and different generation of TPL-induced PGCCs with daughter cells. Scattered PGCCs survived from the treatment of TPL and produced small-sized daughter cells 20-30 days after treatment. Compared to the control cells, the first generation of TPL-induced PGCCs with their daughter cells differentially expressed EMT-related proteins including fibronectin, E-cadherin, vimentin, and Twist, and had lower migration, invasion, and proliferation abilities. The abilities of migration, invasion, and proliferation of TPL-induced PGCCs with their daughter cells gradually enhanced as the passages increasing, and markedly exceeded the control cells in the tenth generation. TPL-induced PGCCs with their daughter cells gradually obtain the abilities of invasion and metastasis in vitro as the number of passage increasing, which can be used to mimick the cancer cells subjected to anti-cancer drugs in vivo and may provide some new insights to explore the mechanism of cancer invasion, metastasis and relapse after chemotherapy.

Wnt Signaling in Cancer Metabolism and Immunity

The Wingless (Wnt)/β-catenin pathway has long been associated with tumorigenesis, tumor plasticity, and tumor-initiating cells called cancer stem cells (CSCs). Wnt signaling has recently been implicated in the metabolic reprogramming of cancer cells. Aberrant Wnt signaling is considered to be a driver of metabolic alterations of glycolysis, glutaminolysis, and lipogenesis, processes essential to the survival of bulk and CSC populations. Over the past decade, the Wnt pathway has also been shown to regulate the tumor microenvironment (TME) and anti-cancer immunity. Wnt ligands released by tumor cells in the TME facilitate the immune evasion of cancer cells and hamper immunotherapy. In this review, we illustrate the role of the canonical Wnt/β-catenin pathway in cancer metabolism and immunity to explore the potential therapeutic approach of targeting Wnt signaling from a metabolic and immunological perspective.

Intermediate Filaments as Effectors of Cancer Development and Metastasis: A Focus on Keratins, Vimentin, and Nestin

Intermediate filament (IF) proteins make up the largest family of cytoskeletal proteins in metazoans, and are traditionally known for their roles in fostering structural integrity in cells and tissues. Remarkably, individual IF genes are tightly regulated in a fashion that reflects the type of tissue, its developmental and differentiation stages, and biological context. In cancer, IF proteins serve as diagnostic markers, as tumor cells partially retain their original signature expression of IF proteins. However, there are also characteristic alterations in IF gene expression and protein regulation. The use of high throughput analytics suggests that tumor-associated alterations in IF gene expression have prognostic value. Parallel research is also showing that IF proteins directly and significantly impact several key cellular properties, including proliferation, death, migration, and invasiveness, with a demonstrated impact on the development, progression, and characteristics of various tumors. In this review, we draw from recent studies focused on three IF proteins most associated with cancer (keratins, vimentin, and nestin) to highlight how several “hallmarks of cancer” described by Hanahan and Weinberg are impacted by IF proteins. The evidence already in hand establishes that IF proteins function beyond their classical roles as markers and serve as effectors of tumorigenesis.

Pro-Nifuroxazide Self-Assembly Leads to Triggerable Nanomedicine for Anti-cancer Therapy

Transcription factor STAT3 has been shown to regulate genes that are involved in stem cell self-renewal and thus represents a novel therapeutic target of great biological significance. However, many small-molecule agents with potential effects through STAT3 modulation in cancer therapy lack aqueous solubility and high off-target toxicity, hence impeding efficient bioavailability and activity. This work, for the first time, reports a prodrug-based strategy for selective and safer delivery of STAT3 inhibitors designed toward metastatic and drug-resistant breast cancer. We have synthesized a novel lipase-labile SN-2 phospholipid prodrug from a clinically investigated STAT3 inhibitor, nifuroxazide (Pro-nifuroxazide), which can be regioselectively cleaved by the membrane-abundant enzymes in cancer cells. Pro-nifuroxazide self-assembled to sub 20 nm nanoparticles (NPs), and the cytotoxic ability was screened in ER(+)-MCF-7 and ER(-)-MD-MB231 cells at 48-72 h using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetra-zolium bromide proliferation assay. Results indicated that Pro-nifuroxazide NPs are multifold more effective toward inhibiting cancer cells in a time-dependent manner compared to parent nifuroxazide. A remarkable improvement in the local concentration of drugs to as high as ∼240 fold when assembled into NPs is presumably the reason for this functional improvement. We also introduced molecular dynamics simulations to generate Pro-nifuroxazide nano-assembly, as a model assembly from triggerable anti-cancer drugs, to provide molecular insights correlating physicochemical and anti-cancer properties. In silico properties of Pro-nifuroxazide including size, chemistry of NPs and membrane interactions with individual molecules could be validated by in vitro functional activities in cells of breast cancer origin. The in vivo anti-cancer efficiencies of Pro-nifuroxazide NPs in nude mice xenografts with MCF-7 revealed remarkable growth inhibition of as high as 400%. Histopathological analysis corroborated these findings to show significantly high nuclear fragmentation and retracted cytoplasm. Immunostaining on tumor section demonstrated a significantly lower level of pSTAT-3 by Pro-nifuroxazide NP treatment, establishing the inhibition of STAT-3 phosphorylation. Our strategy for the first time proposes a translatable prodrug agent self-assembled into NPs and demonstrates remarkable enhancement in IC50, induced apoptosis, and reduced cancer cell population through STAT-3 inhibition via reduced phosphorylation.

Downregulated GBX2 gene suppresses proliferation, invasion and angiogenesis of breast cancer cells through inhibiting the Wnt/β-catenin signaling pathway

OBJECTIVE

Gastrulation brain homeobox 2 (GBX2), a gene involved in mid/hindbrain region, has been revealed as one of the oncogene associated with certain cancers, as an example being prostate cancer. However, despite years of worldwide research, the underlying mechanism of GBX2 as well as its significance in breast cancer still remains unclear. Therefore, the present study evaluates the abilities of GBX gene silencing providing for the proliferation, invasion and angiogenesis of breast cancer cells by way of the Wnt/β-catenin signaling pathway.

METHODS

We employed a microarray analysis to screen out differentially expressed genes relative to breast cancer. Moreover, we retrieved GBX2 expression in breast cancer to find out the relationship between GBX2 expression and prognosis in breast cancer. We performed RT-qPCR to screen out cell lines with high GBX2 expression. Subsequently, both RT-qPCR and western blot analysis were employed so as to measure the combination of the mRNA and protein expressions of GBX2, β-catenin, vascular endothelial growth factor (VEGF), matrix metalloproteinase (MMP)-2, and MMP-9. The effect that GBX2 gene silencing and the Wnt/β-catenin signaling pathway had on cell proliferation, invasion, angiogenesis, and tumorigenic ability were evaluated.

RESULTS

GBX2 gene was also identified having played a role in breast cancer development due to its association with the Wnt/β-catenin signaling pathway. GBX2 gene silencing was found to be an inhibitor for the mRNA and protein expressions regulating β-catenin, VEGF, MMP-2, and MMP-9. Cell proliferation, invasion, angiogenesis, as well as tumorigenic ability in breast cancer were investigated and found to have been suppressed by the GBX2 gene silencing or inactivation of the Wnt/β-catenin signaling pathway.

CONCLUSION

The study has made an attempt to provide evidence to the idea that GBX2 gene silencing has an inhibition effect on the proliferation, invasion and angiogenesis of the breast cancer cells by inhibiting the activation of the Wnt/β-catenin signaling pathway.

Endothelial cells are a source of Nestin expression in Pulmonary Arterial Hypertension

Uncontrolled proliferation of endothelial cells is essential to the pathogenesis of pulmonary arterial hypertension (PAH). Both proliferation and cytoskeleton reorganization are associated with upregulation of the intermediate filament protein Nestin. Recently, accumulation of Nestin-expressing cells was found in pulmonary vascular lesions of PAH patients. The goal of this study is to determine if Nestin expression contributes to endothelial proliferation in pulmonary arterial hypertension, using both lung tissues and endothelial cells. Here we found that endothelial cells from complex and plexiform lesions of PAH patients expressed Nestin. These Nestin+ cells further stained positive for the angiogenic factors CXC chemokine ligand 12 and Wnt1. Likewise, in the chronic hypoxia/SU5416 animal model of pulmonary hypertension, Nestin+ endothelial cells were found in occlusive pulmonary vascular lesions. In vitro, both growing rat and human lung endothelial cells expressed Nestin protein. When Nestin was overexpressed in endothelial cells (both rat and human), Nestin overexpression promoted proliferation and expression of CXC chemokine ligand 12. Nestin overexpression further increased angiogenic tube formation in vitro. Conclusions: We found increased Nestin expression from endothelial cells of occlusive lung vascular lesions in severe pulmonary hypertension. Elevated Nestin expression likely contributes to unchecked pulmonary vascular proliferation and angiogenesis, possibly via induction of CXC chemokine ligand 12. Additional studies are required to determine whether targeting Nestin would be beneficial to treat PAH.

Nestin in immature embryonic neurons affects axon growth cone morphology and Semaphorin3a sensitivity

Correct wiring in the neocortex requires that responses to an individual guidance cue vary among neurons in the same location, and within the same neuron over time. Nestin is an atypical intermediate filament expressed strongly in neural progenitors and is thus used widely as a progenitor marker. Here we show a subpopulation of embryonic cortical neurons that transiently express nestin in their axons. Nestin expression is thus not restricted to neural progenitors, but persists for 2-3 d at lower levels in newborn neurons. We found that nestin-expressing neurons have smaller growth cones, suggesting that nestin affects cytoskeletal dynamics. Nestin, unlike other intermediate filament subtypes, regulates cdk5 kinase by binding the cdk5 activator p35. Cdk5 activity is induced by the repulsive guidance cue Semaphorin3a (Sema3a), leading to axonal growth cone collapse in vitro. Therefore, we tested whether nestin-expressing neurons showed altered responses to Sema3a. We find that nestin-expressing newborn neurons are more sensitive to Sema3a in a roscovitine-sensitive manner, whereas nestin knockdown results in lowered sensitivity to Sema3a. We propose that nestin functions in immature neurons to modulate cdk5 downstream of the Sema3a response. Thus, the transient expression of nestin could allow temporal and/or spatial modulation of a neuron's response to Sema3a, particularly during early axon guidance.

Limonin attenuates the stemness of breast cancer cells via suppressing MIR216A methylation

Limonin has been shown to exert anti-inflammatory effects, however, its roles in tumor progression remain unclear. This work aims to investigate the roles and related mechanism of limonin in the stemness of breast cancer cells. Here, we found that limonin attenuated the stemness of breast cancer cells in a concentration-dependent manner, evident by the decreasing the capacity of cell spheroid formation, expression of stemness markers and ALDH1 activity, whereas had no toxicity on non-tumorigenic cells. Additionally, limonin enhanced adriamycin sensitivity of breast cancer cells and attenuated adriamycin resistance in adriamycin-resistant breast cancer cells. Mechanistically, limonin decreased MIR216A methylation level and thus increased miR-216a-3p expression. Furthermore, miR-216a-3p could directly bind to WNT3A and thus inactivated Wnt/β-catenin pathway. Therefore, our results indicate that limonin could attenuate the stemness and chemoresistance via inhibiting MIR216A methylation and subsequently suppressing Wnt/β-catenin pathway.

Angiomotin-p130 inhibits β-catenin stability by competing with Axin for binding to tankyrase in breast cancer

Growing evidence indicates that Angiomotin (Amot)-p130 and Amot-p80 have different physiological functions. We hypothesized that Amot-p130 is a tumor suppressor gene in breast cancer, in contrast with the canonical oncogenicity of Amot-p80 or total Amot. To clarify the role of Amot-p130 in breast cancer, we performed real-time quantitative PCR, western blotting, flow cytometry, microarray, immunofluorescence, immunoprecipitation, and tumor sphere-formation assays in vitro, as well as tumorigenesis and limited-dilution analysis in vivo. In this study, we showed that Amot-p130 inhibited the proliferation, migration, and invasion of breast cancer cells. Interestingly, transcriptional profiles indicated that genes differentially expressed in response to Amot-p130 knockdown were mostly related to β-catenin signaling in MCF7 cells. More importantly, most of the downstream partners of β-catenin were associated with stemness. In a further validation, Amot-p130 inhibited the cancer stem cell potential of breast cancer cells both in vitro and in vivo. Mechanistically, Amot-p130 decreased β-catenin stability by competing with Axin for binding to tankyrase, leading to a further inhibition of the WNT pathway. In conclusions, Amot-p130 functions as a tumor suppressor gene in breast cancer, disrupting β-catenin stability by competing with Axin for binding to tankyrase. Amot-p130 was identified as a potential target for WNT pathway-targeted therapies in breast cancer.