Wnt/β-catenin signaling pathway upregulates c-Myc expression to promote cell proliferation of P19 teratocarcinoma cells

Merkel Cell Polyomavirus targets SET/PP2A complex to promote cellular proliferation and migration

Merkel Cell Carcinoma (MCC) is a rare neuroendocrine skin cancer. In our previous work, we decoded genes specifically deregulated by MCPyV early genes as opposed to other polyomaviruses and established functional importance of NDRG1 in inhibiting cellular proliferation and migration in MCC. In the present work, we found the SET protein, (I2PP2A, intrinsic inhibitor of PP2A) upstream of NDRG1 which was modulated by MCPyV early genes, both in hTERT-HK-MCPyV and MCPyV-positive (+) MCC cell lines. Additionally, MCC dermal tumour nodule tissues showed strong SET expression. Inhibition of the SET-PP2A interaction in hTERT-HK-MCPyV using the small molecule inhibitor, FTY720, increased NDRG1 expression and inhibited cell cycle regulators, cyclinD1 and CDK2. SET inhibition by shRNA and FTY720 also decreased cell proliferation and colony formation in MCPyV(+) MCC cells. Overall, these results pave a path for use of drugs targeting SET protein for the treatment of MCC.

Dysregulation of deubiquitination in breast cancer

Breast cancer (BC) is a highly frequent malignant tumor that poses a serious threat to women's health and has different molecular subtypes, histological subtypes, and biological features, which act by activating oncogenic factors and suppressing cancer inhibitors. The ubiquitin-proteasome system (UPS) is the main process contributing to protein degradation, and deubiquitinases (DUBs) are reverse enzymes that counteract this process. There is growing evidence that dysregulation of DUBs is involved in the occurrence of BC. Herein, we review recent research findings in BC-associated DUBs, describe their nature, classification, and functions, and discuss the potential mechanisms of DUB-related dysregulation in BC. Furthermore, we present the successful treatment of malignant cancer with DUB inhibitors, as well as analyzing the status of targeting aberrant DUBs in BC.

Ellagic Acid and Cancer Hallmarks: Insights from Experimental Evidence

Cancer is a complex and multifaceted disease with a high global incidence and mortality rate. Although cancer therapy has evolved significantly over the years, numerous challenges persist on the path to effectively combating this multifaceted disease. Natural compounds derived from plants, fungi, or marine organisms have garnered considerable attention as potential therapeutic agents in the field of cancer research. Ellagic acid (EA), a natural polyphenolic compound found in various fruits and nuts, has emerged as a potential cancer prevention and treatment agent. This review summarizes the experimental evidence supporting the role of EA in targeting key hallmarks of cancer, including proliferation, angiogenesis, apoptosis evasion, immune evasion, inflammation, genomic instability, and more. We discuss the molecular mechanisms by which EA modulates signaling pathways and molecular targets involved in these cancer hallmarks, based on in vitro and in vivo studies. The multifaceted actions of EA make it a promising candidate for cancer prevention and therapy. Understanding its impact on cancer biology can pave the way for developing novel strategies to combat this complex disease.

The Myc Family and the Metastasis Suppressor NDRG1: Targeting Key Molecular Interactions with Innovative Therapeutics

Cancer is a leading cause of death worldwide, resulting in ∼10 million deaths in 2020. Major oncogenic effectors are the Myc proto-oncogene family, which consists of three members including c-Myc, N-Myc, and L-Myc. As a pertinent example of the role of the Myc family in tumorigenesis, amplification of MYCN in childhood neuroblastoma strongly correlates with poor patient prognosis. Complexes between Myc oncoproteins and their partners such as hypoxia-inducible factor-1α and Myc-associated protein X (MAX) result in proliferation arrest and pro-proliferative effects, respectively. Interactions with other proteins are also important for N-Myc activity. For instance, the enhancer of zest homolog 2 (EZH2) binds directly to N-Myc to stabilize it by acting as a competitor against the ubiquitin ligase, SCFFBXW7, which prevents proteasomal degradation. Heat shock protein 90 may also be involved in N-Myc stabilization since it binds to EZH2 and prevents its degradation. N-Myc downstream-regulated gene 1 (NDRG1) is downregulated by N-Myc and participates in the regulation of cellular proliferation via associating with other proteins, such as glycogen synthase kinase-3β and low-density lipoprotein receptor-related protein 6. These molecular interactions provide a better understanding of the biologic roles of N-Myc and NDRG1, which can be potentially used as therapeutic targets. In addition to directly targeting these proteins, disrupting their key interactions may also be a promising strategy for anti-cancer drug development. This review examines the interactions between the Myc proteins and other molecules, with a special focus on the relationship between N-Myc and NDRG1 and possible therapeutic interventions. SIGNIFICANCE STATEMENT: Neuroblastoma is one of the most common childhood solid tumors, with a dismal five-year survival rate. This problem makes it imperative to discover new and more effective therapeutics. The molecular interactions between major oncogenic drivers of the Myc family and other key proteins; for example, the metastasis suppressor, NDRG1, may potentially be used as targets for anti-neuroblastoma drug development. In addition to directly targeting these proteins, disrupting their key molecular interactions may also be promising for drug discovery.

The Fgf9-Nolz1-Wnt2 axis regulates morphogenesis of the lung

Morphological development of the lung requires complex signal crosstalk between the mesenchymal and epithelial progenitors. Elucidating the genetic cascades underlying signal crosstalk is essential to understanding lung morphogenesis. Here, we identified Nolz1 as a mesenchymal lineage-specific transcriptional regulator that plays a key role in lung morphogenesis. Nolz1 null mutation resulted in a severe hypoplasia phenotype, including a decreased proliferation of mesenchymal cells, aberrant differentiation of epithelial cells and defective growth of epithelial branches. Nolz1 deletion also downregulated Wnt2, Lef1, Fgf10, Gli3 and Bmp4 mRNAs. Mechanistically, Nolz1 regulates lung morphogenesis primarily through Wnt2 signaling. Loss-of-function and overexpression studies demonstrated that Nolz1 transcriptionally activated Wnt2 and downstream β-catenin signaling to control mesenchymal cell proliferation and epithelial branching. Exogenous Wnt2 could rescue defective proliferation and epithelial branching in Nolz1 knockout lungs. Finally, we identified Fgf9 as an upstream regulator of Nolz1. Collectively, Fgf9-Nolz1-Wnt2 signaling represents a novel axis in the control of lung morphogenesis. These findings are relevant to lung tumorigenesis, in which a pathological function of Nolz1 is implicated.

ALDH2 promotes cancer stemness and metastasis in colorectal cancer through activating β-catenin signaling

Colorectal cancer (CRC) is the primary cause of death from gastrointestinal cancers. Aldehyde dehydrogenase 2 (ALDH2), a crucial mitochondrial enzyme for the oxidative pathway of alcohol metabolism, plays a dual role in cancer progression. In some cancers, it is tumor suppressive; in others, it drives cancer progression. However, whether targeting ALDH2 has any therapeutic implications or prognostic value in CRC is still unclear. Here, we investigated the role of ALDH2 in CRC progression by targeting its enzymatic activity rather than gene expression. We found that inhibiting ALDH2 by CVT-10216 and daidzein significantly decrease migration and stemness properties of both DLD-1 and HCT 116 cells, whereas activating ALDH2 by Alda-1 enhances migration rate. Concomitantly, ALDH2 inhibition by both CVT-10216 and daidzein downregulates the mRNA levels of fibronectin, snail, twist, MMP7, CD44, c-Myc, SOX2, and OCT-4, which are oncogenic in the advanced stage of CRC. Furthermore, Gene Set Enrichment Analysis (GSEA) on ALDH2 co-expressed genes from The Cancer Genome Atlas (TCGA) revealed that MYC target gene sets are upregulated. We found that ALDH2 inhibition decreased the nuclear protein levels of pGSK3β serine 9 and c-Myc. This suggests that ALDH2 probably targets β-catenin signaling in CRC cells. Together, our results demonstrate the prognostic value of ALDH2 in CRC as it regulates both CRC stemness and migration. Our findings also propose that the plant-derived isoflavone daidzein could be a potential chemotherapeutic drug targeting ALDH2 in CRC.

When Just One Phosphate Is One Too Many: The Multifaceted Interplay between Myc and Kinases

Myc transcription factors are key regulators of many cellular processes, with Myc target genes crucially implicated in the management of cell proliferation and stem pluripotency, energy metabolism, protein synthesis, angiogenesis, DNA damage response, and apoptosis. Given the wide involvement of Myc in cellular dynamics, it is not surprising that its overexpression is frequently associated with cancer. Noteworthy, in cancer cells where high Myc levels are maintained, the overexpression of Myc-associated kinases is often observed and required to foster tumour cells' proliferation. A mutual interplay exists between Myc and kinases: the latter, which are Myc transcriptional targets, phosphorylate Myc, allowing its transcriptional activity, highlighting a clear regulatory loop. At the protein level, Myc activity and turnover is also tightly regulated by kinases, with a finely tuned balance between translation and rapid protein degradation. In this perspective, we focus on the cross-regulation of Myc and its associated protein kinases underlying similar and redundant mechanisms of regulation at different levels, from transcriptional to post-translational events. Furthermore, a review of the indirect effects of known kinase inhibitors on Myc provides an opportunity to identify alternative and combined therapeutic approaches for cancer treatment.

Role of the Paf1 complex in the maintenance of stem cell pluripotency and development

Cell identity is determined by the transcriptional regulation of a cell-type-specific gene group. The Paf1 complex (Paf1C), an RNA polymerase II-associating factor, is an important transcriptional regulator that not only participates in transcription elongation and termination but also affects transcription-coupled histone modifications and chromatin organisation. Recent studies have shown that Paf1C is involved in the expression of genes required for self-renewal and pluripotency in stem cells and tumorigenesis. In this review, we focused on the role of Paf1C as a critical transcriptional regulator in cell fate decisions. Paf1C affects the pluripotency of stem cells by regulating the expression of core transcription factors such as Oct4 and Nanog. In addition, Paf1C directly binds to the promoters or distant elements of target genes, thereby maintaining the pluripotency in embryonic stem cells derived from an early stage of the mammalian embryo. Paf1C is upregulated in cancer stem cells, as compared with that in cancer cells, suggesting that Paf1C may be a target for cancer therapy. Interestingly, Paf1C is involved in multiple developmental stages in Drosophila, zebrafish, mice and even humans, thereby displaying a trend for the correlation between Paf1C and cell fate. Thus, we propose that Paf1C is a critical contributor to cell differentiation, cell specification and its characteristics and could be employed as a therapeutic target in developmental diseases.

Actions of WNT family member 5A to regulate characteristics of development of the bovine preimplantation embryo†

WNT signaling is important for regulation of embryonic development. The most abundant WNT gene expressed in the bovine endometrium during the preimplantation period is WNT5A. One objective was to determine whether WNT5A regulates competence of the bovine preimplantation embryo to become a blastocyst and alters the number of cells in the inner cell mass and trophectoderm. A second objective was to delineate features of the cell-signaling mechanisms involved in WNT5A actions. WNT5A caused a concentration-dependent increase in the proportion of embryos developing to the blastocyst stage and in the number of inner cell mass cells in the resultant blastocysts. A concentration of 200 ng/mL was most effective, and a higher concentration of 400 ng/mL was not stimulatory. Bovine serum albumin in culture reduced the magnitude of effects of WNT5A on development to the blastocyst stage. WNT5A affected expression of 173 genes at the morula stage; all were upregulated by WNT5A. Many of the upregulated genes were associated with cell signaling. Actions of WNT5A on development to the blastocyst stage were suppressed by a Rho-associated coiled-coil kinase (ROCK) signaling inhibitor, suggesting that WNT5A acts through Ras homology gene family member A (RhoA)/ROCK signaling. Other experiments indicated that actions of WNT5A are independent of the canonical β-catenin signaling pathway and RAC1/c-Jun N-terminal kinase (JNK) signaling. This is the first report outlining the actions of WNT5A to alter the development of the mammalian embryo. These findings provide insights into how embryokines regulate maternal-embryonic communication.

Isolation, Maintenance and Expansion of Adult Hematopoietic Stem/Progenitor Cells and Leukemic Stem Cells

Simple Summary

Transplantation of adult hematopoietic stem cells is an important therapeutic tool to help patients suffering from diverse hematological disorders. All types of blood cells can develop from a single hematopoietic stem cell underlining their enormous potential. Intense efforts are ongoing to generate “engraftable” human hematopoietic stem cells to treat hematopoietic diseases and to understand the molecular machinery driving them. Leukemic stem cells represent a low frequency subpopulation of leukemia cells that possess stem cell properties. They can instigate, maintain, and serially propagate leukemia in vivo, while they retain the capacity to differentiate into committed progenitors. Leukemic stem cells are unaffected by many therapeutic strategies and represent the major cause of relapse. We here describe all methods to maintain and expand murine and human hematopoietic cells in culture and describe their specific advantages. These methods are also employed to understand the biology of leukemic stem cells and to identify novel therapeutic strategies.

Abstract

Hematopoietic stem cells (HSCs) are rare, self-renewing cells that perch on top of the hematopoietic tree. The HSCs ensure the constant supply of mature blood cells in a tightly regulated process producing peripheral blood cells. Intense efforts are ongoing to optimize HSC engraftment as therapeutic strategy to treat patients suffering from hematopoietic diseases. Preclinical research paves the way by developing methods to maintain, manipulate and expand HSCs ex vivo to understand their regulation and molecular make-up. The generation of a sufficient number of transplantable HSCs is the Holy Grail for clinical therapy. Leukemia stem cells (LSCs) are characterized by their acquired stem cell characteristics and are responsible for disease initiation, progression, and relapse. We summarize efforts, that have been undertaken to increase the number of long-term (LT)-HSCs and to prevent differentiation towards committed progenitors in ex vivo culture. We provide an overview and compare methods currently available to isolate, maintain and enrich HSC subsets, progenitors and LSCs and discuss their individual advantages and drawbacks.

WSB1 regulates c-Myc expression through β-catenin signaling and forms a feedforward circuit

The dysregulation of transcription factors is widely associated with tumorigenesis. As the most well-defined transcription factor in multiple types of cancer, c-Myc can transform cells by transactivating various downstream genes. Given that there is no effective way to directly inhibit c-Myc, c-Myc targeting strategies hold great potential for cancer therapy. In this study, we found that WSB1, which has a highly positive correlation with c-Myc in 10 cancer cell lines and clinical samples, is a direct target gene of c-Myc, and can positively regulate c-Myc expression, which forms a feedforward circuit promoting cancer development. RNA sequencing results from Bel-7402 cells confirmed that WSB1 promoted c-Myc expression through the β-catenin pathway. Mechanistically, WSB1 affected β-catenin destruction complex-PPP2CA assembly and E3 ubiquitin ligase adaptor β-TRCP recruitment, which inhibited the ubiquitination of β-catenin and transactivated c-Myc. Of interest, the effect of WSB1 on c-Myc was independent of its E3 ligase activity. Moreover, overexpressing WSB1 in the Bel-7402 xenograft model could further strengthen the tumor-driven effect of c-Myc overexpression. Thus, our findings revealed a novel mechanism involved in tumorigenesis in which the WSB1/c-Myc feedforward circuit played an essential role, highlighting a potential c-Myc intervention strategy in cancer treatment.

Combinatorial therapy using RNAi and curcumin nano-architectures regresses tumors in breast and colon cancer models

Cancer is a debilitating disease and one of the leading causes of death in the world. In spite of the current clinical management being dependent on applying robust pathological variables and well-defined therapeutic strategies, there is an imminent need for novel and targeted therapies with least side effects. RNA interference (RNAi) has gained attention due to its precise potential for targeting multiple genes involved in cancer progression. Nanoparticles with their enhanced permeability and retention (EPR) effect have been found to overcome the limitations of RNAi-based therapies. With their high transportation capacity, nanocarriers can target RNAi molecules to tumor tissues and protect them from enzymatic degradation. Accumulating evidence has shown that tyrosine kinase Ephb4 is overexpressed in various cancers. Therefore, we report here the development and pre-clinical validation of curcumin-chitosan-loaded: eudragit-coated nanocomposites conjugated with Ephb4 shRNA as a feasible bio-drug to suppress breast and colon cancers. The proposed bio-drug is non-toxic and bio-compatible with a higher uptake efficiency and through our experimental results we have demonstrated the effective site-specific delivery of this biodrug and the successfull silencing of their respective target genes in vivo in autochthonous knockout models of breast and colon cancer. While mammary tumors showed a considerable decrease in size, oral administration of the biodrug conjugate to Apc knockout colon models prolonged the animal survival period by six months. Hence, this study has provided empirical proof that the combinatorial approach involving RNA interference and nanotechnology is a promising alliance for next-generation cancer therapeutics.

Therapeutic Potential of the Cyclin-Dependent Kinase Inhibitor Flavopiridol on c-Myc Overexpressing Esophageal Cancer

Tumors with elevated c-Myc expression often exhibit a highly aggressive phenotype, and c-Myc amplification has been shown to be frequent in esophageal cancer. Emerging data suggests that synthetic lethal interactions between c-Myc pathway activation and small molecules inhibition involved in cell cycle signaling can be therapeutically exploited to preferentially kill tumor cells. We therefore investigated whether exploiting elevated c-Myc expression is effective in treating esophageal cancer with the CDK inhibitor flavopiridol. We found frequent overexpression of c-Myc in human esophageal cancer cell lines and tissues. c-Myc overexpression correlated with accelerated esophageal cancer subcutaneous xenograft tumor growth. Esophageal cancer cells with elevated c-Myc expression were found preferentially more sensitive to induction of apoptosis by the CDK inhibition flavopiridol compared to esophageal cancer cells with lower c-Myc expression. In addition, we observed that flavopiridol alone or in combination with the chemotherapeutic agent nanoparticle albumin-bound paclitaxel (NPT) or in combinations with the targeted agent BMS-754807 significantly inhibited esophageal cancer cell proliferation and subcutaneous xenograft tumor growth while significantly enhancing overall mice survival. These results indicate that aggressive esophageal cancer cells with elevated c-Myc expression are sensitive to the CDK inhibitor flavopiridol, and that flavopiridol alone or in combination can be a potential therapy for c-Myc overexpressing esophageal cancer.

Transcription Factor DLX5 Promotes Hair Follicle Stem Cell Differentiation by Regulating the c-MYC/microRNA-29c-3p/NSD1 Axis

Introduction

Adult stem cell function has been one of the most intensively explored areas of biological and biomedical research, with hair follicle stem cells serving as one of the best model systems. This study explored the role of the transcription factor DLX5 in regulating hair follicle stem cell (HFSC) differentiation.

Methods

HFSCs were isolated, characterized, and assessed for their expression of DLX5, c-MYC, NSD1, and miR-29c-3p using RT-qPCR, Western blot analysis, or immunofluorescence. Next, the ability of HFSCs to proliferate as well as differentiate into either sebaceous gland cells or epidermal cells was determined. The binding of DLX5 to the c-MYC promoter region, the binding of c-MYC to the miR-29c-3p promoter region, and the binding of miR-29c-3p to the 3′-UTR of NSD1 mRNA were verified by luciferase activity assay and ChIP experiments.

Results

DLX5 was highly expressed in differentiated HFSCs. DLX5 transcriptionally activated c-MYC expression to induce HFSC differentiation. c-MYC was able to bind the miR-29c-3p promoter and thus suppressed its expression. Without miR-29c-3p mediated suppression, NSD1 was then able to promote HFSC differentiation. These in vitro experiments suggested that DLX5 could promote HFSC differentiation via the regulation of the c-MYC/miR-29c-3p/NSD1 axis.

Discussion

This study demonstrates that DLX5 promotes HFSC differentiation by modulating the c-MYC/miR-29c-3p/NSD1 axis and identifies a new mechanism regulating HFSC differentiation.

A feedback circuit comprising EHD1 and 14-3-3ζ sustains β-catenin/c-Myc-mediated aerobic glycolysis and proliferation in non-small cell lung cancer

Mammalian Eps15 homology domain 1 (EHD1) participates in the development of non-small cell lung cancer (NSCLC). However, its role in mediating aerobic glycolysis remains unclear. Herein, microarray analysis revealed that EHD1 expression was significantly correlated with the glycolysis/gluconeogenesis pathway. Clinically, EHD1 expression was positively correlated with the maximum standard uptake value (SUVmax) in ¹⁸F-FDG PET/CT scans. Additionally, EHD1 knockdown inhibited aerobic glycolysis and proliferation in vitro and in vivo. Furthermore, Wnt/β-catenin signaling was identified as a critical EHD1-regulated pathway. Co-IP, native gel electrophoresis, and immunoblotting showed that EHD1 contributed to 14-3-3 dimerization via 14-3-3ζ and subsequent activation of β-catenin/c-Myc signaling. Analysis of the EHD1 regulatory region via ENCODE revealed the potential for c-Myc recruitment, leading to transcriptional activation of EHD1 and formation of an EHD1/14-3-3ζ/β-catenin/c-Myc positive feedback circuit. Notably, blocking this circuit with a Wnt/β-catenin inhibitor dramatically inhibited tumor growth in vivo. The positive correlations among EHD1, 14-3-3ζ, c-Myc, and LDHA were further confirmed in NSCLC tissues. Collectively, our study demonstrated that EHD1 activates a 14-3-3ζ/β-catenin/c-Myc regulatory circuit that synergistically promotes aerobic glycolysis and may constitute a promising therapeutic target for NSCLC.

RFX1: a promising therapeutic arsenal against cancer

Regulatory factor X1 (RFX1) is an evolutionary conserved transcriptional factor that influences a wide range of cellular processes such as cell cycle, cell proliferation, differentiation, and apoptosis, by regulating a number of target genes that are involved in such processes. On a closer look, these target genes also play a key role in tumorigenesis and associated events. Such observations paved the way for further studies evaluating the role of RFX1 in cancer. These studies were indispensable due to the failure of conventional chemotherapeutic drugs to target key cellular hallmarks such as cancer stemness, cellular plasticity, enhanced drug efflux, de-regulated DNA repair machinery, and altered pathways evading apoptosis. In this review, we compile significant evidence for the tumor-suppressive activities of RFX1 while also analyzing its oncogenic potential in some cancers. RFX1 induction decreased cellular proliferation, modulated the immune system, induced apoptosis, reduced chemoresistance, and sensitized cancer stem cells for chemotherapy. Thus, our review discusses the pleiotropic function of RFX1 in multitudinous gene regulations, decisive protein–protein interactions, and also its role in regulating key cell signaling events in cancer. Elucidation of these regulatory mechanisms can be further utilized for RFX1 targeted therapy.

MYPT1, regulated by miR-19b-3p inhibits the progression of non-small cell lung cancer via inhibiting the activation of wnt/β-catenin signaling

AIMS

Myosin phosphatase targeting protein 1 (MYPT1) was identified to function as a tumor suppressor in several kinds of cancers, but its role and the molecular mechanisms in non-small cell lung cancer (NSCLC) remain undiscovered. Herein, we aimed to reveal MYPT1 expression pattern and role in NSCLC, and investigate the underlying mechanisms.

MAIN METHODS

Sixty-eight paired NSCLC tissues and the adjacent normal tissues were included in this study. Western blotting and quantitative reverse transcription-polymerase chain (qPCR) technologies were applied for protein and RNA detection. CCK-8, colony formation, flow cytometry, wound healing, transwell chambers coated with Matrigel and in vivo experiments were applied to detect cell viability, colony formation, apoptosis, migration, invasiveness and tumorigenesis, respectively.

KEY FINDINGS

MYPT1 expressed at a lower level in NSCLC tissues as compared with the adjacent normal tissues, which predicted advanced clinic process and poor prognosis. Overexpression of MYPT1 resulted in obvious inhibitions in cell viability, colony formation, migration, invasiveness and tumorigenesis, and induced cell apoptotic rates, as well as decreased the expression levels of β-catenin and TCF4. Besides, overexpression of β-catenin weakened the above roles of MYPT1. In addition, the luciferase gene reporter assay verified that MYPT1 was a target of miR-19b-3p. Further experiments showed that miR-19b-3p promoted cell viability, invasiveness and migration and repressed cell apoptosis by targeting MYPT1.

SIGNIFICANCE

In conclusion, this study demonstrates that MYPT1, regulated by miR-19b-3p, inhibits the progression of NSCLC via inhibiting the activation of wnt/β-catenin signaling.

Tissue-specific transplantation antigen P35B functions as an oncogene and is regulated by microRNA-125a-5p in lung cancer

Tissue‑specific transplantation antigen P35B (TSTA3) expression is upregulated in esophageal squamous cell carcinoma and breast cancer, and functions as an oncogene in breast cancer. However, the roles and underlying mechanisms of TSTA3 in lung cancer have not been fully elucidated. The current study aimed to reveal the role of TSTA3 in lung cancer and explore whether TSTA3 may be modulated by microRNA (miR)‑125a‑5p to activate β‑catenin signaling. Immunohistochemical staining and western blotting were used to analyze TSTA3 expression in lung cancer tissues and cells. Cell functions were assessed via Cell Counting Kit‑8, flow cytometry, wound‑healing, Transwell and in vivo tumor formation assays. The effect of TSTA3 on the activation of β‑catenin signaling was determined using western blot and immunofluorescence analyses. The association between miR‑125a‑5p and TSTA3 was determined by western blotting and luciferase gene reporter assay. The present study revealed that, compared with normal tissues and cells, TSTA3 expression was significantly increased in lung cancer tissues and cell lines, and high TSTA3 expression predicted a poor prognosis and more malignant clinical features in patients with lung cancer. TSTA3 upregulation significantly enhanced β‑catenin expression and promoted its nuclear accumulation. In addition, TSTA3 expression was negatively regulated by miR‑125a‑5p, which was downregulated in lung cancer. Furthermore, TSTA3 overexpression markedly promoted cell proliferation, migration, invasion and tumorigenesis, and suppressed cell apoptosis. TSTA3 downregulation abolished the effects of miR‑125a‑5p downregulation on promoting lung cancer cell malignant transformation. Overall, the current study demonstrates that TSTA3 is regulated by miR‑125a‑5p and functions as an oncogene in lung cancer via promoting the activation of β‑catenin signaling.

Fluid shear stress promotes embryonic stem cell pluripotency via interplay between β-catenin and vinculin in bioreactor culture

The expansion of pluripotent stem cells (PSCs) as aggregates in stirred suspension bioreactors is garnering attention as an alternative to adherent culture. However, the hydrodynamic environment in the bioreactor can modulate PSC behavior, pluripotency and differentiation potential in ways that need to be well understood. In this study, we investigated how murine embryonic stem cells (mESCs) sense fluid shear stress and modulate a noncanonical Wnt signaling response to promote pluripotency. mESCs showed higher expression of pluripotency marker genes, Oct4, Sox2, and Nanog in the absence of leukemia inhibitory factor (LIF) in stirred suspension bioreactors compared to adherent culture, a phenomenon we have termed mechanopluripotency. In bioreactor culture, fluid shear promoted the nuclear translocation of the less well-known pluripotency regulator β-catenin and concomitant increase of c-Myc expression, an upstream regulator of Oct4, Sox2, and Nanog. We also observed similar β-catenin nuclear translocation in LIF-free mESCs cultured on E-cadherin substrate under defined fluid shear stress conditions in flow chamber plates. mESCs showed lower shear-induced expression of pluripotency marker genes when β-catenin was inhibited, suggesting that β-catenin signaling is crucial to mESC mechanopluripotency. Key to this process is vinculin, which is known to rearrange and associate more strongly with adherens junctions in response to fluid shear. When the vinculin gene is disrupted, we observe that nuclear β-catenin translocation and mechanopluripotency are abrogated. Our results indicate that mechanotransduction through the adherens junction complex is important for mESC pluripotency maintenance.

Piperine and Celecoxib synergistically inhibit colon cancer cell proliferation via modulating Wnt/β-catenin signaling pathway

BACKGROUND

Celecoxib (CXB), a selective COX-2 inhibitor NSAID, has exhibited prominent anti-proliferative potential against numerous cancers. However, its low bioavailability and long term exposure related cardiovascular side effects, limit its clinical application. In order to overcome these limitations, natural bioactive compounds with lower toxicity profile are used in combination with therapeutic drugs. Therfore, in this study Piperine (PIP), a natural chemo-preventive agent possessing drug bioavailability enhancing properties, was considered to be used in combination with low doses of CXB.

PURPOSE

We hypothesized that the combination of PIP with CXB will have a synergistic anti-proliferative effect on colon cancer cells.

STUDY DESIGN

The potency of PIP and CXB alone and in combination was evaluated in HT-29 human colon adenocarcinoma cells and mechanism of growth inhibition was investigated by analyzing the players in apoptotic and Wnt/β-catenin signaling pathways.

METHODS

The effect of PIP on the oral bioavailability of CXB in mice was investigated using HPLC analysis. The study investigated the synergistic anti-proliferative effect of CXB and PIP on HT-29 cells and IEC-6 non-tumorigenic rat intestinal epithelial cells by SRB cell viability assay. Further, the cellular and molecular mechanism(s) involved in the anti-proliferative combinatorial effect was extensively explored in HT-29 cells by flow cytometry and western blotting. The in vivo efficacy of this combination was studied in CT26.WT tumor syngeneic Balb/c mice model.

RESULTS

PIP as a bioenhancer increased the oral bioavailability of CXB (129%). The IC50 of CXB and PIP were evaluated to select doses for combination treatment of HT-29 cells. The drug combinations having combination index (CI) less than 1 were screened using CompuSyn software. These combinations were significantly cytotoxic to HT-29 cells but IEC-6 were least effected. Further, the mechanism behind CXB and PIP mediated cell death was explored. The co-treatment led to reactive oxygen species generation, mitochondrial dysfunction, caspase activation and enhanced apoptosis in HT-29 cells. Additionally, the combination treatment synergistically modulated Wnt/β-catenin pathway, downregulated the stemness markers and boosted therapeutic response in CT26 syngeneic Balb/c mice.

CONCLUSION

The outcomes of the study suggests that combining CXB and PIP offers a novel approach for the treatment of colon cancer.

Secreted phosphoprotein-1 accelerates the progression of human colorectal cancer through activating β-catenin signaling

Colorectal cancer (CRC) is a common malignant tumor of the digestive tract and one of the leading causes of cancer-associated mortality. Secreted phosphoprotein-1 (SPP-1) is overexpressed in CRC and promotes cancer progression, but the underlying mechanisms underlying SPP-1 function remain unclear. The present study aimed to explore the effects of Wnt/β-catenin signaling in SPP-1-induced CRC progression. The expression patterns of SPP-1 in CRC tissues were examined using reverse transcription-quantitative (RT-q)PCR, western blotting and immunohistochemistry. SPP-1 expression in cells was assessed using RT-qPCR and western blotting. Cell-Counting Kit-8, flow cytometry and tumor-burdened mice experiments were used to determine cell proliferation, apoptosis and in vivo tumor formation abilities. The results showed that SPP-1 expression was markedly elevated in CRC tissues and cells compared with that in normal colorectal tissues and cells. High expression of SPP-1 was associated with advanced clinical process and low overall survival rate in patients with CRC. Besides, SPP-1 could interact with β-catenin and positively regulated β-catenin protein expression, and enhanced its nuclear accumulation. Moreover, SPP-1-upregulation significantly enhanced cell proliferation and in vivo tumor formation ability, and reduced apoptosis, whereas these effects were all abolished when β-catenin was silenced. Overall, the present study revealed that SPP-1 promoted the progression of CRC in a β-catenin-dependent manner.

Neural signaling modulates metabolism of gastric cancer

Tumors comprise cancer cells and the associated stromal and immune/inflammatory cells, i.e., tumor microenvironment (TME). Here, we identify a metabolic signature of human and mouse model of gastric cancer and show that vagotomy in the mouse model reverses the metabolic reprogramming, reflected by metabolic switch from glutaminolysis to OXPHOS/glycolysis and normalization of the energy metabolism in cancer cells and TME. We next identify and validate SNAP25, mTOR, PDP1/α-KGDH, and glutaminolysis as drug targets and accordingly propose a therapeutic strategy to target the nerve-cancer metabolism. We demonstrate the efficacy of nerve-cancer metabolism therapy by intratumoral injection of BoNT-A (SNAP25 inhibitor) with systemic administration of RAD001 and CPI-613 but not cytotoxic drugs on overall survival in mice and show the feasibility in patients. These findings point to the importance of neural signaling in modulating the tumor metabolism and provide a rational basis for clinical translation of the potential strategy for gastric cancer.

•

Metabolic reprogramming in gastric cancer cells and tumor microenvironment

•

SNAP25, mTOR, PDP1/α-KGDH, and glutaminolysis as potential drug targets

•

Combination of botulinum toxin type A, RAD001, and CPI-613 as a potential treatment

Leishmania regulates host macrophage miRNAs expression by engaging transcription factor c-Myc

Parasites of Leishmania genus have developed sophisticated strategies allowing them to deactivate their host macrophage to promote their survival. It has become clear that miRNAs play important roles in shaping innate and adaptive immune responses toward pathogens. It is not surprising that several pathogens including Leishmania have evolved the ability to regulate host macrophage miRNA expression in order to manipulate host cell phenotypes to their advantage. However, very little is known about the mechanisms used by intracellular pathogens to drive changes in host cell miRNA abundance. In this review, Leishmania exploitation of macrophage transcription factor c-Myc as a critical proxy virulence factor to regulate abundance of macrophage miRNAs influencing macrophage physiology to promote its survival will be discussed.

A Possible Role of FZD10 Delivering Exosomes Derived from Colon Cancers Cell Lines in Inducing Activation of Epithelial-Mesenchymal Transition in Normal Colon Epithelial Cell Line

Exosomes belong to the family of extracellular vesicles released by every type of cell both in normal and pathological conditions. Growing interest in studies indicates that extracellular vesicles, in particular, the fraction named exosomes containing lipids, proteins and nucleic acid, represent an efficient way to transfer functional cargoes between cells, thus combining all the other cell-cell interaction mechanisms known so far. Only a few decades ago, the involvement of exosomes in the carcinogenesis in different tissues was discovered, and very recently it was also observed how they carry and modulate the presence of Wnt pathway proteins, involved in the carcinogenesis of gastrointestinal tissues, such as Frizzled 10 protein (FZD10), a membrane receptor for Wnt. Here, we report the in vitro study on the capability of tumor-derived exosomes to induce neoplastic features in normal cells. Exosomes derived from two different colon cancer cell lines, namely the non-metastatic CaCo-2 and the metastatic SW620, were found to deliver, in both cases, FZD10, thus demonstrating the ability to reprogram normal colonic epithelial cell line (HCEC-1CT). Indeed, the acquisition of specific mesenchymal characteristics, such as migration capability and expression of FZD10 and markers of mesenchymal cells, was observed. The exosomes derived from the metastatic cell line, characterized by a level of FZD10 higher than the exosomes extracted from the non-metastatic cells, were also more efficient in stimulating EMT activation. The overall results suggest that FZD10, delivered by circulating tumor-derived exosomes, can play a relevant role in promoting the CRC carcinogenesis and propagation.

MiR-26a-5p Serves as an Oncogenic MicroRNA in Non-Small Cell Lung Cancer by Targeting FAF1

Purpose

Non-small cell lung cancer (NSCLC) accounts for approximately 80–85% of all lung cancers, with the FAS-associated factor 1 (FAF1) acting as a tumor suppressor. MicroRNAs (miRNAs) can influence cancer progression by targeting oncogenes or anti-oncogenes. In this study, we aimed to reveal the influence of miR-26a-5p on the regulation of FAF1 expression and NSCLC progression, with the motivation of identifying a potential therapeutic target for NSCLC treatment.

Methods

A dual-luciferase reporter assay was used to check for the direct targeting of FAF1 by miR-26a-3p. The miR-26a-5p inhibitor or FAF1 shRNA plasmid was transfected into A549 and H1299 cells to modulate FAF1 expression. Then, the effect of miR-26a-5p/FAF1 on cellular functions was investigated. MTT assay was used to evaluate cell viability. EdU proliferation assay and cell cycle assay were performed to analyze the effect of miR-26a-5p on cell replication and cell cycle. We used annexin V-FITC and PI to stain apoptotic cells, followed by flow cytometric analysis. Transwell and wound healing assays were performed to investigate metastasis. Moreover, the effect of miR-26a-5p/FAF1 on cancer progression was examined in vivo. Lastly, the underlying mechanism was uncovered using RT-qPCR, Western blotting, and TOP/FOP flash assay.

Results

miR-26a-5p was found to directly target FAF1 and downregulate its expression. Blocking miR-26a-5p inhibited the cell growth, migration, and invasion, but promoted cell apoptosis. In addition, this inhibited the growth of tumor in mice. FAF1 knockdown reversed the functions of miR-26a-5p. Further, miR-26a-5p/FAF1 was observed to play an important role in the Wnt signaling pathway, regulating the expression of genes such as AXIN, c-Myc, and cyclin-D1.

Conclusion

Taken together, we show that miR-26a-5p functions as an oncogenic microRNA in NSCLC by targeting FAF1 and may serve as a potential target for NSCLC treatment.

Trefoil Factor Family 1 Inhibits the Development of Hepatocellular Carcinoma by Regulating β-Catenin Activation

BACKGROUND AND AIMS

Recent studies have suggested that trefoil factor family 1 (TFF1) functions as a tumor suppressor in gastric and pancreatic carcinogenesis.

APPROACH AND RESULTS

To investigate the role of TFF1 in hepatocarcinogenesis, we performed immunohistochemical staining of surgically resected human liver samples, transfected a TFF1 expression vector into hepatocellular carcinoma (HCC) cell lines, and employed a mouse model of spontaneous HCC development (albumin-cyclization recombination/Lox-Stop-Lox sequence-Kirsten rat sarcoma viral oncogene homolog^G12D [KC]); the model mouse strain was bred with a TFF1-knockout mouse strain to generate a TFF1-deficient HCC mouse model (KC/TFF1^-/- ). TFF1 expression was found in some human samples with HCC. Interestingly, TFF1-positive cancer cells showed a staining pattern contradictory to that of proliferating cell nuclear antigen, and aberrant DNA hypermethylation in TFF1 promoter lesions was detected in HCC samples, indicating the tumor-suppressive role of TFF1. In vitro, induction of TFF1 expression resulted in impaired proliferative activity and enhanced apoptosis in HCC cell lines (HuH7, HepG2, and HLE). These anticancer effects of TFF1 were accompanied by the loss of nuclear β-catenin expression, indicating inactivation of the β-catenin signaling pathway by TFF1. In vivo, TFF1 deficiency in KC mice accelerated the early development and growth of HCC, resulting in poor survival rates. In addition, immunohistochemistry revealed that the amount of nuclear-localized β-catenin was significantly higher in KC/TFF1^-/- mice than in KC mice and that human HCC tissue showed contradictory expression patterns for β-catenin and TFF1, confirming the in vitro observations.

CONCLUSIONS

TFF1 might function as a tumor suppressor that inhibits the development of HCC by regulating β-catenin activity.

Nuclear receptor CAR-mediated liver cancer and its species differences

Introduction: The nuclear receptor CAR plays an important role in the regulation of hepatic responses to xenobiotic exposure, including the induction of hepatocyte proliferation and chemical carcinogenesis. Phenobarbital, a well-known liver cancer promoter, has been found to promote hepatocyte proliferation via CAR activation. However, the molecular mechanisms by which CAR induces liver carcinogenesis remain unknown. In addition, it is believed that CAR-mediated liver carcinogenesis shows a species difference; phenobarbital treatment induces hepatocyte proliferation and liver cancer in rodents but not in humans. However, the mechanisms are also unknown.Areas covered: Several reports indicate that the key oncogenic signaling pathways Wnt/β-catenin and Hippo/YAP are involved in CAR-mediated liver carcinogenesis. We introduce current data about the possible molecular mechanisms involved in CAR-mediated liver carcinogenesis and species differences by focusing on these two signaling pathways.Expert opinion: CAR may activate both the Wnt/β-catenin and Hippo/YAP signaling pathways. The synergistic activation of both signaling pathways seems to be important for CAR-mediated liver cancer development. Low homology between the ligand binding domains of human CAR and rodent CAR might cause species differences in the interactions with proteins that control the Wnt/β-catenin and Hippo/YAP pathways as well as liver cancer induction.

Glucose restriction combined with chemotherapy decreases telomere length and cancer antigen-125 secretion in ovarian carcinoma

Although chemotherapy is the standard treatment for ovarian cancer (OC), recent studies have focused on its coupling with hypoglycemic drugs to decrease glucose availability. Similarly to cancer antigen 125 (Ca-125), telomerase, the key protein for telomere lengthening, is overexpressed in 90% of OC cases. The aim of the present study was to investigate the effect of the combination of glucose restriction and chemotherapy on telomere length and Ca-125 secretion in OC cells. SKOV-3, OVCAR-3 and Igrov-1 cells were treated with 20 µM cisplatin and 100 nM paclitaxel for 48 h in three different glucose concentrations: i) 4.5 g/l, ii) 1 g/l and iii) 0.5 g/l. The same treatment was repeated once per week for 6 consecutive weeks. The surviving cells were considered platinum-taxane escape (PTES) cells. The expression levels of telomerase and Ca-125 in treated and PTES cells were quantified by qPCR, and Ca-125 secretion by ELISA. Telomere length was evaluated by qPCR according to the Cawthon method. The modulation of Ca-125 by telomerase was assessed using inhibitors, small interfering RNA and transfection with human telomerase reverse transcriptase (hTERT) vectors. The implication of phosphatidylinositol-4,5-bisphosphate 3-kinase/protein kinase B/mechanistic target of rapamycin (PI3K/Akt/mTOR) in Ca-125 modulation was investigated using specific inhibitors. An increase in hTERT and Ca-125 expression levels (range, 1.5-3 fold) was observed in short-term treated cells. However, an opposite effect was detected in PTES cells, where the rate of decrease in the expression levels of hTERT and Ca-125 reached 60% after treatment in 0.5 g/l glucose. Moreover, telomere length was decreased by 30% in cells treated with 0.5 g/l glucose. Inhibition of hTERT expression significantly decreased Ca-125 secretion, suggesting a potential modulation of Ca-125 by hTERT. The inhibition of the PI3K/Akt/mTOR pathway also decreased Ca-125 secretion; however, the effect of this treatment was not enhanced when coupled with telomerase inhibitors. In conclusion, the combination of chemotherapy and glucose restriction was observed to decrease Ca-125 secretion and telomerase expression leading to shortening in telomere length. Thus, decreasing glucose availability for OC cells during treatment may lead to a better clinical outcome and potentially improve the prognosis of patients with OC.

Lanatoside C Induces G2/M Cell Cycle Arrest and Suppresses Cancer Cell Growth by Attenuating MAPK, Wnt, JAK-STAT, and PI3K/AKT/mTOR Signaling Pathways

Cardiac glycosides (CGs) are a diverse family of naturally derived compounds having a steroid and glycone moiety in their structures. CG molecules inhibit the α-subunit of ubiquitous transmembrane protein Na⁺/K⁺-ATPase and are clinically approved for the treatment of cardiovascular diseases. Recently, the CGs were found to exhibit selective cytotoxic effects against cancer cells, raising interest in their use as anti-cancer molecules. In this current study, we explored the underlying mechanism responsible for the anti-cancer activity of Lanatoside C against breast (MCF-7), lung (A549), and liver (HepG2) cancer cell lines. Using Real-time PCR, western blot, and immunofluorescence studies, we observed that (i) Lanatoside C inhibited cell proliferation and induced apoptosis in cell-specific and dose-dependent manner only in cancer cell lines; (ii) Lanatoside C exerts its anti-cancer activity by arresting the G2/M phase of cell cycle by blocking MAPK/Wnt/PAM signaling pathways; (iii) it induces apoptosis by inducing DNA damage and inhibiting PI3K/AKT/mTOR signaling pathways; and finally, (iv) molecular docking analysis shows significant evidence on the binding sites of Lanatoside C with various key signaling proteins ranging from cell survival to cell death. Our studies provide a novel molecular insight of anti-cancer activities of Lanatoside C in human cancer cells.

LGR5 and Downstream Intracellular Signaling Proteins Play Critical Roles in the Cell Proliferation of Neuroblastoma, Meningioma and Pituitary Adenoma

Leucine-rich repeat-containing G-protein coupled receptor 5 (LGR5) has been reported to play critical roles in the proliferation of various cancer cells. However, the roles of LGR5 in brain tumors and the specific intracellular signaling proteins directly associated with it remain unknown. Expression of LGR5 was first measured in normal brain tissue, meningioma, and pituitary adenoma of humans. To identify the downstream signaling pathways of LGR5, siRNA-mediated knockdown of LGR5 was performed in SH-SY5Y neuroblastoma cells followed by proteomics analysis with 2-dimensional polyacrylamide gel electrophoresis (2D-PAGE). In addition, the expression of LGR5-associated proteins was evaluated in LGR5-inhibited neuroblastoma cells and in human normal brain, meningioma, and pituitary adenoma tissue. Proteomics analysis showed 12 protein spots were significantly different in expression level (more than two-fold change) and subsequently identified by peptide mass fingerprinting. A protein association network was constructed from the 12 identified proteins altered by LGR5 knockdown. Direct and indirect interactions were identified among the 12 proteins. HSP 90-beta was one of the proteins whose expression was altered by LGR5 knockdown. Likewise, we observed decreased expression of proteins in the hnRNP subfamily following LGR5 knockdown. In addition, we have for the first time identified significantly higher hnRNP family expression in meningioma and pituitary adenoma compared to normal brain tissue. Taken together, LGR5 and its downstream signaling play critical roles in neuroblastoma and brain tumors such as meningioma and pituitary adenoma.

A GLIS3-CD133-WNT-signaling axis regulates the self-renewal of adult murine pancreatic progenitor-like cells in colonies and organoids

The existence and regenerative potential of resident stem and progenitor cells in the adult pancreas are controversial topics. A question that has been only minimally addressed is the capacity of a progenitor cell to self-renew, a key attribute that defines stem cells. Previously, our laboratory has identified putative stem and progenitor cells from the adult murine pancreas. Using an ex vivo colony/organoid culture system, we demonstrated that these stem/progenitor-like cells have self-renewal and multilineage differentiation potential. We have named these cells pancreatic colony-forming units (PCFUs) because they can give rise to three-dimensional colonies. However, the molecular mechanisms by which PCFUs self-renew have remained largely unknown. Here, we tested the hypothesis that PCFU self-renewal requires GLIS family zinc finger 3 (GLIS3), a zinc-finger transcription factor important in pancreas development. Pancreata from 2- to 4-month-old mice were dissociated, sorted for CD133^highCD71^low ductal cells, known to be enriched for PCFUs, and virally transduced with shRNAs to knock down GLIS3 and other proteins. We then plated these cells into our colony assays and analyzed the resulting colonies for protein and gene expression. Our results revealed a previously unknown GLIS3-to-CD133-to-WNT signaling axis in which GLIS3 and CD133 act as factors necessary for maintaining WNT receptors and signaling molecules in colonies, allowing responses to WNT ligands. Additionally, we found that CD133, but not GLIS3 or WNT, is required for phosphoinositide 3-kinase (PI3K)/AKT Ser/Thr kinase (AKT)-mediated PCFU survival. Collectively, our results uncover a molecular pathway that maintains self-renewal of adult murine PCFUs.

Burkitt-like lymphoma in a pediatric patient with familial adenomatous polyposis

Familial adenomatous polyposis (FAP) is an autosomal dominant condition that predisposes to multiple malignancies, most commonly colorectal carcinoma, but has rarely been associated with lymphoma. We discuss one patient found to have Burkitt-like Lymphoma (BLL) with 11q aberration in the setting of previously undiagnosed FAP. We review the literature of FAP and associated malignancies and the provisional WHO classification of Burkitt-like lymphoma with 11q aberration. Both FAP and Burkitt-like lymphoma with 11q aberration involve perturbation of the MYC network and this may provide insight into a connection between these two diagnoses. However, further study is needed to elucidate if there is an increased risk of BLL and other subtypes of lymphoma among patients with FAP in order to provide optimal counseling and surveillance for patients with FAP.

Chronic iron exposure and c-Myc/H-ras-mediated transformation in fallopian tube cells alter the expression of EVI1, amplified at 3q26.2 in ovarian cancer

Mechanisms underlying the pathogenesis of high-grade serous epithelial ovarian cancers (HGSOC) are not yet well defined although key precursor cells have been identified (including fimbriated fallopian tube epithelium, FTSECs). Since iron is elevated in endometriotic cysts and the pelvic cavity, it is suggested that this source of redox-active iron may contribute to ovarian cancer pathogenesis. Specifically, sources of nontransferrin-bound iron (NTBI) within the pelvic cavity could arise from ovulation, retrograde menstruation, follicular fluid, or iron overload conditions (i.e., hemochromatosis). Herein, we investigated the cellular response of p53-inactivated and telomerase-expressing (immortalized) FTSECs (Pax8⁺/FoxJ1⁻) to NTBI (presented as ferric ammonium citrate (FAC), supplemented in media for >2 months) in order to assess its ability to promote the transition to a tumor-like phenotype; this cellular response was compared with immortalized FTSECs transformed with H-Ras^V12A and c-Myc^T58A. Both approaches resulted in increased cell numbers and expression of the oncogenic transcriptional regulator, ecotropic virus integration site 1 (EVI1, a gene most frequently amplified at 3q26.2 in HGSOC, represented by multiple variants), along with other oncogenic gene products. In contrast to the transformed cells, FAC-exposed FTSECs elicited elevated migratory capacity (and epithelial–mesenchymal transition mRNA profile) along with increased expression of DNA damage response proteins (i.e., FANCD2) and hTERT mRNA relative to controls. Interestingly, in FAC-exposed FTSECs, EVI1 siRNA attenuated hTERT mRNA expression, whereas siRNAs targeting β-catenin and BMI1 (both elevated with chronic iron exposure) reduced Myc and Cyclin D1 proteins. Collectively, our novel findings provide strong foundational evidence for potential iron-induced initiation events, including EVI1 alterations, in the pathogenesis of HGSOC, warranting further in depth investigations. Thus, these findings will substantially advance our understanding of the contribution of iron enriched within the pelvic cavity, which may identify patients at risk of developing this deadly disease.

Leucine zipper and ICAT domain containing (LZIC) protein regulates cell cycle transitions in response to ionizing radiation

Common hallmarks of cancer include the dysregulation of cell cycle progression and the acquisition of genome instability. In tumors, G1 cell cycle checkpoint induction is often lost. This increases the reliance on a functional G2/M checkpoint to prevent progression through mitosis with damaged DNA, avoiding the introduction of potentially aberrant genetic alterations. Treatment of tumors with ionizing radiation (IR) utilizes this dependence on the G2/M checkpoint. Therefore, identification of factors which regulate this process could yield important biomarkers for refining this widely used cancer therapy. Leucine zipper and ICAT domain containing (LZIC) downregulation has been associated with the development of IR-induced tumors. However, despite LZIC being highly conserved, it has no known molecular function. We demonstrate that LZIC knockout (KO) cell lines show a dysregulated G2/M cell cycle checkpoint following IR treatment. In addition, we show that LZIC deficient cells competently activate the G1 and early G2/M checkpoint but fail to maintain the late G2/M checkpoint after IR exposure. Specifically, this defect was found to occur downstream of PIKK signaling. The LZIC KO cells demonstrated severe aneuploidy indicative of genomic instability. In addition, analysis of data from cancer patient databases uncovered a strong correlation between LZIC expression and poor prognosis in several cancers. Our findings suggest that LZIC is functionally involved in cellular response to IR, and its expression level could serve as a biomarker for patient stratification in clinical cancer practice.

Wnt/β-Catenin Signaling Pathway-Related Proteins (DKK-3, β-Catenin, and c-MYC) Are Involved in Prognosis of Nasopharyngeal Carcinoma

The Wnt/β-catenin signaling pathway is one of the highly conserved signaling pathway widely reported to play essential roles in the development of various tumors and human cancers, thus serving as a potential target for anticancer therapy. However, the specific effects of the related proteins in the Wnt/β-catenin signaling pathway in nasopharyngeal carcinoma (NPC) still remain elusive. Thus, this study was performed to uncover the correlation between the Wnt/β-catenin signaling pathway-related proteins and the clinical characteristics and prognosis of NPC. NPC tissues were revealed to present high expression of β-catenin and v-myc myelocytomatosis viral oncogene homolog (c-MYC) but low expression of Dickkopf-3 (DKK-3). Immunohistochemical staining revealed that DKK-3 was positively linked to but β-catenin and c-MYC were negatively linked to differentiation, tumor-node-metastasis (TNM) stage and lymph node metastasis of patients with NPC. In addition, c-MYC was identified to be positively correlated to DKK-3 in NPC tissues. The positive expression of β-catenin and c-MYC had negative relations with and that of DKK-3 had positive relations with survival rate of patients with NPC, which was analyzed by Kaplan-Meier method. Moreover, it was shown that later TNM stage and positive expression of β-catenin were risk factors for NPC-related death. These findings provide evidence that the proteins related to the Wnt/β-catenin signaling pathway (DKK-3, β-catenin, and c-MYC) participate in the development of NPC and positive expression of DKK-3 and negative expression of β-catenin, and c-MYC can serve as essential prognostic biomarkers, shedding new light on the prognosis and treatment of NPC.

Wnt Signaling Pathway Linked to Intestinal Regeneration via Evolutionary Patterns and Gene Expression in the Sea Cucumber Apostichopus japonicus

Many echinoderms are regenerative species that exhibit exceptional regenerative capacity, and sea cucumber is a representative organism that could regenerate the whole intestine after evisceration. There are many signaling pathways participate in the regeneration process, but it is not clear which is essential for the intestinal regeneration. In this study, we performed genome-wide comprehensive analyses on these regeneration-related signaling pathways, and found the Wnt signaling pathway was one of the most conservative pathways among regenerative species. Additionally, among these signaling pathways, we found that the Wnt signaling pathway was the only one under positive selection in regenerative echinoderms, and the only one enriched by differentially expressed genes during the intestinal regeneration. Thus, it suggests both coding sequence and gene expression of the Wnt signaling pathway have been shaped by natural selection to provide the genetic architecture for intestinal regeneration. Wnt7, Fz7, and Dvl are the three positively selected genes and also happen to be three upstream genes in the Wnt signaling pathway. They are all significantly upregulated at the early stages of regeneration, which may contribute significantly to the early activation of Wnt signaling and the initiation of intestinal regeneration. Expression knockdown of Wnt7 and Dvl by RNA interference significantly inhibit intestinal extension, implying that they are essential for intestinal regeneration. As an important regeneration-related gene, the downstream gene c-Myc is also conserved and highly expressed during the whole regeneration stages, which may make the Wnt/c-Myc signaling to be an important way to promote intestinal regeneration. Therefore, it is reasonable to conclude that the Wnt signaling pathway is the chosen one to play an important role in intestinal regeneration of sea cucumbers, or even in the regeneration of other echinoderms.

Translocations involving ETS family proteins in human cancer

The ETS transcription factors regulate expression of genes involved in normal cell development, proliferation, differentiation, angiogenesis, and apoptosis, consisting of 28 family members in humans. Dysregulation of these transcription factors facilitates cell proliferation in cancers, and several members participate in invasion and metastasis by activating certain gene transcriptions. ETS1 and ETS2 are the founding members of the ETS family and regulate transcription by binding to ETS sequences. Three chimeric genes involving ETS genes have been identified in human cancers, which are EWS-FLI1 in Ewing's sarcoma, TMPRSS2-ERG in prostate cancer, and ETV6-RUNX1 in acute lymphocytic leukemia. Although these fusion transcripts definitely contribute to the pathogenesis of the disease, the impact of these fusion transcripts on patients' prognosis is highly controversial. In the present review, the roles of ETS protein translocations in human carcinogenesis are discussed.

Characterization of canonical Wnt signalling changes after induced disruption of Müller cell in murine retina

Müller cells are the primary glia in the retina, playing a critical role in retinal homeostasis and retinal pathology. This study evaluated the canonical Wnt signalling pathway and its downstream effects on retinal degeneration in a transgenic mouse model of inducible Müller cell disruption. Increased expression of the LacZ reporter gene in the retina suggested Wnt signalling had been activated after induced Müller cell disruption. Activation was validated by observing nuclear translocation of β-Catenin. The mRNA expression of 80 Wnt related genes were assessed using real-time PCR. The Wnt signalling inhibitors Dkk1, Dkk3 and sFRP3 were significantly downregulated. Furthermore, the ubiquitin-mediated β-Catenin proteolysis genes β-TrCP and SHFM3, were also significantly downregulated. The downstream target genes of the Wnt signalling, including Fra1, CyclinD2 and C-Myc were upregulated. The changes of these genes at the protein level were validated by Western blot. Their distributions in the retina were evaluated by immunofluorescent staining. Our findings indicate that Müller cells are involved in retinal Wnt signalling. Activation of Wnt signalling and its downstream target genes may play important roles in photoreceptor degeneration and neovascularization occurring in the retina after induced disruption of Müller cells.

USP20 positively regulates tumorigenesis and chemoresistance through β-catenin stabilization

β-catenin is a major transcriptional activator of the canonical Wnt/β-catenin signaling pathway. It is important for a series of biological processes including tissue homeostasis, and embryonic development and is involved in various human diseases. Elevated oncogenic activity of β-catenin is frequently observed in cancers, which contributes to survival, metastasis and chemo-resistance of cancer cells. However, the mechanism of β-catenin overexpression in cancers is not well defined. Here we demonstrate that the deubiquitination enzyme USP20 is a new regulator of the Wnt/β-catenin signaling pathway. Mechanistically, USP20 regulates the deubiquitination of β-catenin to control its stability, thereby inducing proliferation, invasion and migration of cancer cells. High expression of USP20 correlates with increased β-catenin protein level in multiple cancer cell lines and patient samples. Moreover, knockdown of USP20 increases β-catenin polyubiquitination, which enhances β-catenin turnover and cell sensitivity to chemotherapy. Collectively, our results establish the USP20-β-catenin axis as a critical regulatory mechanism of canonical Wnt/β-catenin signaling pathway with an important role in tumorigenesis and chemo response in human cancers.

Nonhistone targets of KAT2A and KAT2B implicated in cancer biology 1

Lysine acetylation is a critical post-translation modification that can impact a protein's localization, stability, and function. Originally thought to only occur on histones, we now know thousands of nonhistone proteins are also acetylated. In conjunction with many other proteins, lysine acetyltransferases (KATs) are incorporated into large protein complexes that carry out these modifications. In this review we focus on the contribution of two KATs, KAT2A and KAT2B, and their potential roles in the development and progression of cancer. Systems biology demands that we take a broad look at protein function rather than focusing on individual pathways or targets. As such, in this review we examine KAT2A/2B-directed nonhistone protein acetylations in cancer in the context of the 10 "Hallmarks of Cancer", as defined by Hanahan and Weinberg. By focusing on specific examples of KAT2A/2B-directed acetylations with well-defined mechanisms or strong links to a cancer phenotype, we aim to reinforce the complex role that these enzymes play in cancer biology.

Let-7b contributes to hepatocellular cancer progression through Wnt/β-catenin signaling

Elevated evidences show that microRNAs (miRNAs) play vital roles in tumor progression regulation. However, the functional role of let-7b in hepatocellular carcinoma (HCC) is still largely unknown. In this study, we try to investigate the biological activity of let-7b in human HCC cells and try to find the potential regulatory signaling pathway. Our results indicate that let- 7b was remarkably down-regulated in human HCC tissues by qRT-PCR. In addition, let-7b overexpression decreased the expression of β-catenin and c-Myc, while upregulated E-cadherin expression in HCC cells which was verified by quantitative real-time PCR (qRT-PCR) and western blotting. Furthermore, Wnt/β-catenin was involved in let-7b biological activity which was revealed by luciferase assay. Moreover, Wnt/β-catenin signaling inhibitor blocks HCC cell proliferation which is as the same pattern as let-7b overexpression inhibits in HCC cells proliferation. In conclusion, down-regulated let-7b promotes HCC cell proliferation through Wnt/β-catenin signaling in HCC cells. These results suggested that appropriate manipulation of let-7b might be a new treatment of human HCC in the future.

The GSK3 kinase inhibitor lithium produces unexpected hyperphosphorylation of β-catenin, a GSK3 substrate, in human glioblastoma cells

Lithium salt is a classic glycogen synthase kinase 3 (GSK3) inhibitor. Beryllium is a structurally related inhibitor that is more potent but relatively uncharacterized. This study examined the effects of these inhibitors on the phosphorylation of endogenous GSK3 substrates. In NIH-3T3 cells, both salts caused a decrease in phosphorylated glycogen synthase, as expected. GSK3 inhibitors produce enhanced phosphorylation of Ser9 of GSK3β via a positive feedback mechanism, and both salts elicited this enhancement. Another GSK3 substrate is β-catenin, which has a central role in Wnt signaling. In A172 human glioblastoma cells, lithium treatment caused a surprising increase in phospho-Ser33/Ser37-β-catenin, which was quantified using an antibody-coupled capillary electrophoresis method. The β-catenin hyperphosphorylation was unaffected by p53 RNAi knockdown, indicating that p53 is not involved in the mechanism of this response. Lithium caused a decrease in the abundance of axin, a component of the β-catenin destruction complex that has a role in coordinating β-catenin ubiquitination and protein turnover. The axin and phospho-β-catenin results were reproduced in U251 and U87MG glioblastoma cell lines. These observations run contrary to the conventional view of the canonical Wnt signaling pathway, in which a GSK3 inhibitor would be expected to decrease, not increase, phospho-β-catenin levels.

This article has an associated First Person interview with the first author of the paper.

Summary: GSK3 inhibitors have potential use against Alzheimer's disease and other conditions. In this study, a classic inhibitor produced unexpected molecular effects on key components of the Wnt signaling pathway.

E-Cadherin/β-Catenin Complex: A Target for Anticancer and Antimetastasis Plants/Plant-derived Compounds

Plants reputed to have cancer-inhibiting potential and putative active components derived from those plants have emerged as an exciting new field in cancer study. Some of these compounds have cancer-inhibiting potential in different clinical staging levels, especially metastasis. A few of them which stabilize cell-cell adhesions are controversial topics. This review article introduces some effective herbal compounds that target E-cadherin/β-catenin protein complex. In this article, at first, we briefly review the structure and function of E-cadherin and β-catenin proteins, Wnt signaling pathway, and its target genes. Then, effective compounds of the Teucrium persicum, Teucrium polium, Allium sativum (garlic), Glycine max (soy), and Brassica oleracea (broccoli) plants, which influence stability and cellular localization of E-cadherin/β-catenin complex, were studied. Based on literature review, there are some compounds in these plants, including genistein of soy, sulforaphane of broccoli, organosulfur compounds of garlic, and the total extract of Teucrium genus that change the expression of variety of Wnt target genes such as MMPs, E-cadherin, p21, p53, c-myc, and cyclin D1. So they may induce cell-cycle arrest, apoptosis and/or inhibition of Epithelial-Mesenchymal Transition (EMT) and metastasis.

A New View of Pathway-Driven Drug Resistance in Tumor Proliferation

Defeating drug resistance in tumor cell proliferation is challenging. We propose that signaling in cell proliferation takes place via two core pathways, each embodying multiple alternative pathways. We consider drug resistance through an alternative proliferation pathway - within the same or within the other core pathway. Most drug combinations target only one core pathway; blocking both can restrain proliferation. We define core pathways as independent and acting similarly in cell-cycle control, which can explain why their products (e.g., ERK and YAP1) can substitute for each other in resistance. Core pathways can forecast possible resistance because acquired resistance frequently occurs through alternative proliferation pathways. This concept may help to predict the efficacy of drug combinations. The selection of distinct combinations for specific mutated pathways would be guided by clinical diagnosis.

Identification of FERM domain-containing protein 5 as a novel target of β-catenin/TCF7L2 complex

Deregulation of the canonical Wnt signaling pathway plays an important role in human tumorigenesis through the accumulation of β‐catenin and subsequent transactivation of TCF7L2. Although some of the consequences associated with the accumulated β‐catenin have been clarified, the comprehensive effect of activated β‐catenin/TCF7L2 transcriptional complex on tumorigenesis remains to be elucidated. To understand the precise molecular mechanisms underlying colorectal cancer, we searched for genes regulated by the complex in colorectal tumors. We performed expression profile analysis of HCT116 and SW480 colon cancer cells treated with β‐catenin siRNAs, and ChIP‐sequencing using anti‐TCF7L2 antibody. Combination of these data with public microarray data of LS174 cells with a dominant‐negative form of TCF7L2 identified a total of 11 candidate genes. In this paper, we focused on FERM domain‐containing protein 5 (FRMD5), and confirmed that it is regulated by both β‐catenin and TCF7L2. An additional reporter assay disclosed that a region in intron1 transcriptionally regulated the expression of FRMD5. ChIP assay also corroborated that TCF7L2 associates with this region. These data suggested that FRMD5 is a novel direct target of the β‐catenin/TCF7L2 complex.

Chemical inhibition reveals differential requirements of signaling pathways in krasV12- and Myc-induced liver tumors in transgenic zebrafish

Previously we have generated inducible liver tumor models by transgenic expression of an oncogene and robust tumorigenesis can be rapidly induced by activation of the oncogene in both juvenile and adult fish. In the present study, we aimed at chemical intervention of tumorigenesis for understanding molecular pathways of tumorigenesis and for potential development of a chemical screening tool for anti-cancer drug discovery. Thus, we evaluated the roles of several major signaling pathways in krasV12- or Myc-induced liver tumors by using several small molecule inhibitors: SU5402 and SU6668 for VEGF/FGF signaling; IWR1 and cardionogen 1 for Wnt signaling; and cyclopamine and Gant61 for Hedgehog signaling. Inhibition of VEGF/FGF signaling was found to deter both Myc- and krasV12-induced liver tumorigenesis while suppression of Wnt signaling relaxed only Myc- but not krasV12-induced liver tumorigenesis. Inhibiting Hedgehog signaling did not suppress either krasV12 or Myc-induced tumors. The suppression of liver tumorigenesis was accompanied with a decrease of cell proliferation, increase of apoptosis, distorted liver histology. Collectively, our observations suggested the requirement of VEGF/FGF signaling but not the hedgehog signaling in liver tumorigenesis in both transgenic fry. However, Wnt signaling appeared to be required for liver tumorigenesis only in Myc but not krasV12 transgenic zebrafish.

Mechanisms Regulating Stemness and Differentiation in Embryonal Carcinoma Cells

Just over ten years have passed since the seminal Takahashi-Yamanaka paper, and while most attention nowadays is on induced, embryonic, and cancer stem cells, much of the pioneering work arose from studies with embryonal carcinoma cells (ECCs) derived from teratocarcinomas. This original work was broad in scope, but eventually led the way for us to focus on the components involved in the gene regulation of stemness and differentiation. As the name implies, ECCs are malignant in nature, yet maintain the ability to differentiate into the 3 germ layers and extraembryonic tissues, as well as behave normally when reintroduced into a healthy blastocyst. Retinoic acid signaling has been thoroughly interrogated in ECCs, especially in the F9 and P19 murine cell models, and while we have touched on this aspect, this review purposely highlights how some key transcription factors regulate pluripotency and cell stemness prior to this signaling. Another major focus is on the epigenetic regulation of ECCs and stem cells, and, towards that end, this review closes on what we see as a new frontier in combating aging and human disease, namely, how cellular metabolism shapes the epigenetic landscape and hence the pluripotency of all stem cells.