A Small Molecule Inhibitor of the β-Catenin-TCF4 Interaction Suppresses Colorectal Cancer Growth In Vitro and In Vivo

Induction of zinc conjugated with Doxorubicin for the prevention of aggregating β-catenin in the Wnt signaling pathway investigated through computational approaches

Canonical Wnt signaling plays a key role in tumor cell proliferation which correlates with the accumulation of β-catenin resulting inactivation of the network of targets such as GSK3β, Axin, CK1. Uncontrolled expression of β-catenin leads to different types of cancers and other diseases such as sarcoma and mesenchymal tumor formation. However, β-catenin is an attractive target for cervical cancer. In the present study, the compounds such as Doxorubicin and Zinc conjugated with Doxorubicin were screened against β-catenin using Molecular Docking, Molecular Dynamics Simulation, MM/GBSA, and DFT approaches to explore their insights. The study further demonstrated that the binding energy of Zn conjugated with Doxorubicin has shown -7.2 kcal/mol and Doxorubicin registers -5.9 kcal/mol against β-catenin. The disruption between the β-catenin/Tcf-4 complex was observed through the Zinc-Doxorubicin complex, both the proteins are separated about 12 Å. The Zn-Doxorubicin was stabilized with the hydrophobic residues such as Val349 of β-catenin and Phe21 of Tcf-4. The DFT analysis using the B3LYP/6-31g(d,p) method explores that Zn-doxorubicin in complex with the binding site residues has shown the HOMO-LUMO gap of 2.55 eV. The binding free energy calculations exhibit the Zn conjugated Doxorubicin favors in the study by showing ~ 3 kcal/mol difference with Doxorubicin. The Zn-conjugated Doxorubicin will be discussed in the context of cervical cancer with the hope of improving drug efficacy and reducing toxicities for the betterment of the patient's quality of life.

Fusobacterium nucleatum modulates the Wnt/β-catenin pathway in colorectal cancer development

The Wnt/β-catenin signalling pathway normally maintains cellular and tissue homeostasis by regulating cellular differentiation and survival in a controlled manner. An aberrantly regulated Wnt/β-catenin signalling pathway can transform into an oncogenic pathway, which is associated with Colorectal cancer (CRC) as well as other cancers. CRC is one of the most frequently occurring gastrointestinal cancers worldwide. In CRC tissues, deregulation of Wnt/β-catenin pathway is observed, which indicates that this oncogenic pathway directly promotes CRC malignancy, cell migration, angiogenesis, chemoresistance, as well as shorter lifespan of a patient. Growing evidence suggests that human commensal microbes have a strong association with carcinogenesis, particularly the prevalence and high enrichment of Fusobacterium nucleatum in CRC progression. The Wnt/β-catenin pathway is one of the targeted pathways by F. nucleatum in CRC, where Fusobacterium adhesin attaches to E-cadherin to initiate infection. Also, Wnt/β-catenin pathway can be a potential target for the treatment of both CRC and F. nucleatum-positive CRC. Here, we discuss the underlying mechanisms of F. nucleatum-positive CRC development through modulation of Wnt/β-catenin signalling and its possibility for the application in targeted therapy of F. nucleatum-positive CRC.

Organoid modeling reveals the tumorigenic potential of the alveolar progenitor cell state

Cancers display cellular, genetic and epigenetic heterogeneity, complicating disease modeling. Multiple cell states defined by gene expression have been described in lung adenocarcinoma (LUAD). However, the functional contributions of cell state and the regulatory programs that control chromatin and gene expression in the early stages of tumor initiation are not well understood. Using single-cell RNA and ATAC sequencing in Kras/p53-driven tumor organoids, we identified two major cellular states: one more closely resembling alveolar type 2 (AT2) cells (SPC-high), and the other with epithelial-mesenchymal-transition (EMT)-associated gene expression (Hmga2-high). Each state exhibited distinct transcription factor networks, with SPC-high cells associated with TFs regulating AT2 fate and Hmga2-high cells enriched in Wnt- and NFκB-related TFs. CD44 was identified as a marker for the Hmga2-high state, enabling functional comparison of the two populations. Organoid assays and orthotopic transplantation revealed that SPC-high, CD44-negative cells exhibited higher tumorigenic potential within the lung microenvironment. These findings highlight the utility of organoids in understanding chromatin regulation in early tumorigenesis and identifying novel early-stage therapeutic targets in Kras-driven LUAD.

Advances in the development of Wnt/β-catenin signaling inhibitors

The Wnt/β-catenin signaling pathway plays a critical role in various biological processes, including cell proliferation, differentiation, and tissue homeostasis. Aberrant activation of this pathway is strongly associated with the development of various cancers, including colorectal, pancreatic, and gastric cancers, making it a promising therapeutic target. In recent years, inhibitors targeting different components of the Wnt/β-catenin pathway, including small molecules, peptides, and nucleic acid-based therapies, have been developed to suppress cancer cell growth. These inhibitors work by disrupting key interactions within the pathway, thereby preventing tumor progression. Antibody-based therapies have also emerged as potential strategies to block ligand-receptor interactions within this pathway. Despite these advancements, challenges such as the complexity of the pathway and toxicity concerns remain. Innovative approaches, including allosteric inhibitors, proteolysis-targeting chimeras (PROTACs), and peptide-based inhibitors, offer new opportunities to address these challenges. This review provides an overview of the latest progress in the development of Wnt/β-catenin pathway inhibitors and explores future directions in cancer therapy.

A novel drug prejudice scaffold-imidazopyridine-conjugate can promote cell death in a colorectal cancer model by binding to β-catenin and suppressing the Wnt signaling pathway

INTRODUCTION

Globally, colorectal cancer (CRC) is the third most common type of cancer, and its treatment frequently includes the utilization of drugs based on antibodies and small molecules. The development of CRC has been linked to various signaling pathways, with the Wnt/β-catenin pathway identified as a key target for intervention.

OBJECTIVES

We have explored the impact of imidazopyridine-tethered chalcone-C (CHL-C) in CRC models.

METHODS

To determine the influence of CHL-C on apoptosis and autophagy, Western blot analysis, annexin V assay, cell cycle analysis, acridine orange staining, and immunocytochemistry were performed. Next, the activation of the Wnt/β-catenin signaling pathway and the anti-cancer effects of CHL-C in vivo were examined in an orthotopic HCT-116 mouse model.

RESULTS

We describe the synthesis and biological assessment of the CHL series as inhibitors of the viability of HCT-116, SW480, HT-29, HCT-15, and SNU-C2A CRC cell lines. Further biological evaluations showed that CHL-C induced apoptosis and autophagy in down-regulated β-catenin, Wnt3a, FZD-1, Axin-1, and p-GSK-3β (Ser9), and up-regulated p-GSK3β (Tyr216) and β-TrCP. In-depth analysis using structure-based bioinformatics showed that CHL-C strongly binds to β-catenin, with a binding affinity comparable to that of ICG-001, a well-known β-catenin inhibitor. Additionally, our in vivo research showed that CHL-C markedly inhibited tumor growth and triggered the activation of both apoptosis and autophagy in tumor tissues.

CONCLUSION

CHL-C is capable of inducing apoptosis and autophagy by influencing the Wnt/β-catenin signaling pathway.

The evolving roles of Wnt signaling in stem cell proliferation and differentiation, the development of human diseases, and therapeutic opportunities

The evolutionarily conserved Wnt signaling pathway plays a central role in development and adult tissue homeostasis across species. Wnt proteins are secreted, lipid-modified signaling molecules that activate the canonical (β-catenin dependent) and non-canonical (β-catenin independent) Wnt signaling pathways. Cellular behaviors such as proliferation, differentiation, maturation, and proper body-axis specification are carried out by the canonical pathway, which is the best characterized of the known Wnt signaling paths. Wnt signaling has emerged as an important factor in stem cell biology and is known to affect the self-renewal of stem cells in various tissues. This includes but is not limited to embryonic, hematopoietic, mesenchymal, gut, neural, and epidermal stem cells. Wnt signaling has also been implicated in tumor cells that exhibit stem cell-like properties. Wnt signaling is crucial for bone formation and presents a potential target for the development of therapeutics for bone disorders. Not surprisingly, aberrant Wnt signaling is also associated with a wide variety of diseases, including cancer. Mutations of Wnt pathway members in cancer can lead to unchecked cell proliferation, epithelial-mesenchymal transition, and metastasis. Altogether, advances in the understanding of dysregulated Wnt signaling in disease have paved the way for the development of novel therapeutics that target components of the Wnt pathway. Beginning with a brief overview of the mechanisms of canonical and non-canonical Wnt, this review aims to summarize the current knowledge of Wnt signaling in stem cells, aberrations to the Wnt pathway associated with diseases, and novel therapeutics targeting the Wnt pathway in preclinical and clinical studies.

β-catenin inhibitors in cancer therapeutics: intricacies and way forward

β-catenin is an evolutionary conserved, quintessential, multifaceted protein that plays vital roles in cellular homeostasis, embryonic development, organogenesis, stem cell maintenance, cell proliferation, migration, differentiation, apoptosis, and pathogenesis of various human diseases including cancer. β-catenin manifests both signaling and adhesive features. It acts as a pivotal player in intracellular signaling as a component of versatile WNT signaling cascade involved in embryonic development, homeostasis as well as in carcinogenesis. It is also involved in Ca2+ dependent cell adhesion via interaction with E-cadherin at the adherens junctions. Aberrant β-catenin expression and its nuclear accumulation promote the transcription of various oncogenes including c-Myc and cyclinD1, thereby contributing to tumor initiation, development, and progression. β-catenin's expression is closely regulated at various levels including its stability, sub-cellular localization, as well as transcriptional activity. Understanding the molecular mechanisms of regulation of β-catenin and its atypical expression will provide researchers not only the novel insights into the pathogenesis and progression of cancer but also will help in deciphering new therapeutic avenues. In the present review, we have summarized the dual functions of β-catenin, its role in signaling, associated mutations as well as its role in carcinogenesis and tumor progression of various cancers. Additionally, we have discussed the challenges associated with targeting β-catenin molecule with the presently available drugs and suggested the possible way forward in designing new therapeutic alternatives against this oncogene.

Pterostilbene-Isothiocyanate Inhibits Proliferation of Human MG-63 Osteosarcoma Cells via Abrogating β-Catenin/TCF-4 Interaction-A Mechanistic Insight

Osteosarcoma, a highly metastasizing bone neoplasm, is a leading cause of death and disability in children and adolescents worldwide. Osteosarcoma is only suboptimally responsive to surgery and radio- and chemotherapy, that too with adverse side effects. Hence, there is a necessary need for safer alternative therapeutic approaches. This study evaluated the anticancer effects of the semi-synthetic compound, pterostilbene-isothiocyanate (PTER-ITC), on human osteosarcoma MG-63 cells through cytotoxicity, wound-healing, and transwell-migration assays. Results showed that PTER-ITC specifically inhibited the survival, proliferation, and migration of osteosarcoma cells. PTER-ITC induced apoptosis in MG-63 cells by disrupting mitochondrial membrane potential, as evident from the outcomes of different cytological staining. The antimetastatic potential of PTER-ITC was evaluated through immunostaining, RT-qPCR, and immunoblotting. In silico (molecular docking and dynamic simulation) and, subsequently, biochemical [co-immunoprecipitation (Co-IP) and luciferase reporter] assays deciphered the underlying mode-of-action of this compound. PTER-ITC increased E-cadherin and reduced N-cadherin levels, thereby facilitating the reversal of epithelial-mesenchymal transition (EMT). It also modulated the expressions of proliferative cell nuclear antigen (PCNA), caspase-3, poly [ADP-ribose] polymerase (PARP-1) and matrix metalloproteinase-2/9 (MMPs-2/9) at transcriptional and translational levels. PTER-ITC interfered with the β-catenin/transcription factor-4 (TCF-4) interaction in silico by occupying the β-catenin binding site on TCF-4, confirmed by their reduced physical interactions (Co-IP assay). This inhibited transcriptional activation of TCF-4 by β-catenin (as shown by luciferase reporter assay). In conclusion, PTER-ITC exhibited potent anticancer effects in vitro against human osteosarcoma cells by abrogating the β-catenin/TCF-4 interaction. Altogether, this study suggests that PTER-ITC may be regarded as a new approach for osteosarcoma treatment.

TCOF1 promotes the colorectal cancer progression by stabilizing β-catenin

Colorectal cancer (CRC) is one of the highest mortality rates worldwide, and various studies reported to the occurrence of CRC. In particular, the Wnt/β-catenin pathway is known to be a major factor in the progression of CRC and β-catenin involved in the expression of its downstream target genes. We searched for TCOF1 through sliver staining to identify a new binding partner for β-catenin and to investigate the role of the gene involved in CRC. Treacle Ribosome Biogenesis Factor 1 (TCOF1) is a nucleolar protein that regulates the transcription of ribosomal DNA (rDNA). There are many reports of genetic studies on TCOF1 mutations and defects, but its function in CRC remains unknown. We demonstrated that TCOF1 and β-catenin expression in tissue microarray (TMA) containing 101 individual CRC and 17 adjacent normal samples. Additionally, the effects of TCOF1 knockdown or overexpression were examined proliferation, colony formation assay, western blot, and quantitative real-time PCR (qRT-PCR). TCOF1 knockdown or overexpression regulates cell proliferation about three-fold and the phosphorylation of β-catenin, cyclin D1 expression levels. Besides, we discovered the mechanism through which TCOF1 regulates the stability of β-catenin was involved in degradation through proteasome using ubiquitination assay. Finally, we confirmed the interaction of TCOF1 with the tankyrase inhibitor NVP-TNKS656, which destabilizes β-catenin through in vitro and in vivo. Collectively, this study shows that significantly correlation was observed that TCOF1 and β-catenin were risk factor for tumor progression. The stability of β-catenin via regulating TCOF1 expression could be a potential strategy for therapeutic with CRC.

Organoid modeling reveals the tumorigenic potential of the alveolar progenitor cell state

Alveolar type 2 (AT2) cells, the epithelial progenitor cells of the distal lung, are known to be the prominent cell of origin for lung adenocarcinoma. The regulatory programs that control chromatin and gene expression in AT2 cells during the early stages of tumor initiation are not well understood. Here, we dissected the response of AT2 cells to Kras activation and p53 loss (KP) using combined single cell RNA and ATAC sequencing in an established tumor organoid system. Multi-omic analysis showed that KP tumor organoid cells exhibit two major cellular states: one more closely resembling AT2 cells (SPC-high) and another with loss of AT2 identity (hereafter, Hmga2-high). These cell states are characterized by unique transcription factor (TF) networks, with SPC-high states associated with TFs known to regulate AT2 cell fate during development and homeostasis, and distinct TFs associated with the Hmga2-high state. CD44 was identified as a marker of the Hmga2-high state, and was used to separate organoid cultures for functional comparison of these two cell states. Organoid assays and orthotopic transplantation studies indicated that SPC-high cells have higher tumorigenic capacity in the lung microenvironment compared to Hmga2-high cells. These findings highlight the utility of understanding chromatin regulation in the early oncogenic versions of epithelial cells, which may reveal more effective means to intervene the progression of Kras-driven lung cancer.

Medicinal Chemistry Strategies for the Development of Inhibitors Disrupting β-Catenin's Interactions with Its Nuclear Partners

Dysregulation of the Wnt/β-catenin signaling pathway is strongly associated with various aspects of cancer, including tumor initiation, proliferation, and metastasis as well as antitumor immunity, and presents a promising opportunity for cancer therapy. Wnt/β-catenin signaling activation increases nuclear dephosphorylated β-catenin levels, resulting in β-catenin binding to TCF and additional cotranscription factors, such as BCL9, CBP, and p300. Therefore, directly disrupting β-catenin's interactions with these nuclear partners holds promise for the effective and selective suppression of the aberrant activation of Wnt/β-catenin signaling. Herein, we summarize recent advances in biochemical techniques and medicinal chemistry strategies used to identify potent peptide-based and small-molecule inhibitors that directly disrupt β-catenin's interactions with its nuclear binding partners. We discuss the challenges involved in developing drug-like inhibitors that target the interactions of β-catenin and its nuclear binding partner into therapeutic agents.

Emerging Direct Targeting β-Catenin Agents

Aberrant accumulation of β-catenin in the cell nucleus as a result of deregulation of the Wnt/β-catenin pathway is found in various types of cancer. Direct β-catenin targeting agents are being researched despite obstacles; however, specific β-catenin drugs for clinical treatments have not been approved so far. We focused on direct β-catenin targeting of potential therapeutic value as anticancer agents. This review provides recent advances on small molecule β-catenin agents. Structure-activity relationships and biological activities of reported inhibitors are discussed. This work provides useful knowledge in the discovery of β-catenin agents.

Inhibition of the Wnt/b-catenin pathway using PNU-74654 reduces tumor growth in in vitro and in vivo models of colorectal cancer

BACKGROUND

Colorectal-cancer (CRC) is amongst the most lethal-cancers, mainly due to its metastatic spread and drug chemoresistance. Hence there is a need for new approaches to either increase the efficacy of current therapy or introduce new therapies that have greater efficacy. There is increasing evidence that dysregulation of WNT-signaling-pathway plays an essential role in the development and prognosis of CRC. Here we have investigated the therapeutic potential of targeting the WNT/b-catenin pathway using a novel Wnt/b-catenin inhibitor, PNU-74654, in combination with 5-FU in CRC.

METHODS

The anti-proliferative-effect of PNU-74654 was evaluated in two-/three-dimensional cell models. The activity of agents on cell growth, migration, invasion, cell cycle and apoptosis was evaluated by MTT, wound healing assay, invasion, FACS, and annexin V staining, respectively. The oxidant/antioxidant levels were also assessed by determining the level of MDA, SOD, as well as using the DCFH-DA assay. We used a xenograft model of CRC to investigate PNU-74654 activity alone and in combination with 5-FU follow by histological staining and biochemical and gene expression analyses by RT-PCR and western blot.

RESULTS

PNU-74654 inhibited cell-growth and synergistically affected the anti-tumor properties of 5-FU via modulation of Cyclin D1 and survivin. This agent inhibited the migration/invasion of colorectal cancer cells via perturbation of E-cadherin. Furthermore, PNU-74654 inhibited the tumor growth, which was more pronounced using the PNU-74654 plus 5-FU combination via induction of reactive oxygen species, down-regulation of SOD and modulation of MCP-1, P53, TNF-α.

CONCLUSIONS

Our finding demonstrated that PNU-74654 can target Wnt-pathway, interfere with cell-proliferation, induced-cell death, reduced-migration and interact with 5-FU, supporting further investigations on this therapeutic-approach for colorectal cancer.

Moonlighting at the Poles: Non-Canonical Functions of Centrosomes

Centrosomes are best known as the microtubule organizing centers (MTOCs) of eukaryotic cells. In addition to their classic role in chromosome segregation, centrosomes play diverse roles unrelated to their MTOC activity during cell proliferation and quiescence. Metazoan centrosomes and their functional doppelgängers from lower eukaryotes, the spindle pole bodies (SPBs), act as important structural platforms that orchestrate signaling events essential for cell cycle progression, cellular responses to DNA damage, sensory reception and cell homeostasis. Here, we provide a critical overview of the unconventional and often overlooked roles of centrosomes/SPBs in the life cycle of eukaryotic cells.

Targeting the interaction of β-catenin and TCF/LEF transcription factors to inhibit oncogenic Wnt signaling

The Wnt/β-catenin signaling pathway is crucially involved in embryonic development, stem cell maintenance and tissue renewal. Hyperactivation of this pathway is associated with the development and progression of various types of cancers. The transcriptional coactivator β-catenin represents a pivotal component of the pathway and its interaction with transcription factors of the TCF/LEF family is central to pathway activation. Inhibition of this crucial protein-protein interaction via direct targeting of β-catenin is considered a promising strategy for the inactivation of oncogenic Wnt signaling. This review summarizes advances in the development of Wnt antagonists that have been shown to directly bind β-catenin.

What we have learnt from Drosophila model organism: the coordination between insulin signaling pathway and tumor cells

Cancer development is related to a variety of signaling pathways which mediate various cellular processes including growth, survival, division and competition of cells, as well as cell-cell interaction. The insulin signaling pathway interacts with different pathways and plays a core role in the regulations of all these processes. In this study, we reviewed recent studies on the relationship between the insulin signaling pathway and tumors using the Drosophila melanogaster model. We found that on one hand, the insulin pathway is normally hyperactive in tumor cells, which promotes tumor growth, and on the other hand, tumor cells can suppress the growth of healthy tissues via inhibition of their insulin pathway. Moreover, systematic disruption in glucose homeostasis also facilitates cancer development by different mechanisms. The studies on how the insulin network regulates the behaviors of cancer cells may help to discover new therapeutic treatments for cancer.

The Therapeutic Role of PNU-74654 in Hepatocellular Carcinoma May Involve Suppression of NF-κB Signaling

Background and Objectives: PNU-74654, a Wnt/β-catenin inhibitor, has reported antitumor activities; however, the therapeutic potential of PNU-74654 in hepatocellular carcinoma (HCC) has not been investigated in detail. The aim of this study was to clarify the cytotoxic effects of PNU-74654 against HCC and to uncover its molecular mechanism. Materials and Methods: HepG2 and Huh7 liver cancer cell lines were selected to determine the antitumor properties of PNU-74654. Survival of the liver cancer cells in response to PNU-74654 was assessed by cell viability assays, and the apoptosis effect of PNU-74654 was analyzed by flow cytometry and visualized by Hoechst staining. An oncology array was used to explore the underlying molecular routes of PNU-74654 action in the cells. The migration properties were examined with a wound healing assay, and western blotting was conducted to evaluate protein expression. Results: Treatment with PNU-74654 decreased cell viability and inhibited cell migration. The cell cycle analysis and Hoechst staining revealed an increase in the population of cells at the sub-G1 stage and apoptotic morphological changes in the nucleus. The oncology array identified 84 oncology-related proteins and a suppressed expression of Bcl-xL and survivin. Western blotting showed that PNU-74654 could interfere with cell cycle-related proteins through the NF-κB pathway. Conclusions: PNU-74654 shows antiproliferative and antimigration effects against HepG2 and Huh7 cells, and its antitumor activity may be attributable to its interference in cell cycle regulation and the NF-κB pathway.

Biophysical Survey of Small-Molecule β-Catenin Inhibitors: A Cautionary Tale

The canonical Wingless-related integration site signaling pathway plays a critical role in human physiology, and its dysregulation can lead to an array of diseases. β-Catenin is a multifunctional protein within this pathway and an attractive yet challenging therapeutic target, most notably in oncology. This has stimulated the search for potent small-molecule inhibitors binding directly to the β-catenin surface to inhibit its protein–protein interactions and downstream signaling. Here, we provide an account of the claimed (and some putative) small-molecule ligands of β-catenin from the literature. Through in silico analysis, we show that most of these molecules contain promiscuous chemical substructures notorious for interfering with screening assays. Finally, and in line with this analysis, we demonstrate using orthogonal biophysical techniques that none of the examined small molecules bind at the surface of β-catenin. While shedding doubts on their reported mode of action, this study also reaffirms β-catenin as a prominent target in drug discovery.

Molecular implications of HOX genes targeting multiple signaling pathways in cancer

Homeobox (HOX) genes encode highly conserved homeotic transcription factors that play a crucial role in organogenesis and tissue homeostasis. Their deregulation impacts the function of several regulatory molecules contributing to tumor initiation and progression. A functional bridge exists between altered gene expression of individual HOX genes and tumorigenesis. This review focuses on how deregulation in the HOX-associated signaling pathways contributes to the metastatic progression in cancer. We discuss their functional significance, clinical implications and ascertain their role as a diagnostic and prognostic biomarker in the various cancer types. Besides, the mechanism of understanding the theoretical underpinning that affects HOX-mediated therapy resistance in cancers has been outlined. The knowledge gained shall pave the way for newer insights into the treatment of cancer.

Drug discovery efforts toward inhibitors of canonical Wnt/β-catenin signaling pathway in the treatment of cancer: A composition-of-matter review (2010-2020)

The Wnt/β-catenin pathway has a crucial role in the proliferation and differentiation of normal cells as well as the self-renewal and pluripotency of stem cells, including cancer stem cells (CSCs). Targeting this pathway with small-molecule chemotherapeutics, discovered via conventional efforts, has proved difficult. Recently, computer-aided drug discovery efforts have produced promising chemotherapeutics. A concerted effort to develop inhibitors of this pathway through more efficient and cost-effective drug discovery methods could lead to a significant increase in clinically relevant therapeutics. Herein, patents from 2010 to 2020 are reviewed to identify those that have disclosed composition of matter for small-molecule inhibitors of the Wnt/ β-catenin pathway for cancer. We believe that such efforts will provide insights for future therapeutic candidate discovery and development in this field.

Natural products targeting cancer cell dependency

Precision cancer medicine is a tailored treatment approach for individual cancer patients with different genomic characteristics. Mutated or hyperactive oncogenes have served as main drug targets in current precision cancer medicine, while defective or inactivated tumor suppressors in general have not been considered as druggable targets. Synthetic lethality is one of very few approaches that enable to target defective tumor suppressors with pharmacological agents. Synthetic lethality exploits cancer cell dependency on a protein or pathway, which arises when the function of a tumor suppressor is defective. This approach has been proven to be effective in clinical settings since the successful clinical introduction of BRCA-PARP synthetic lethality for the treatment of breast and ovarian cancer with defective BRCA. Subsequently, large-scale screenings with RNAi, CRISPR/Cas9-sgRNAs, and chemical libraries have been applied to identify synthetic lethal partners of tumor suppressors. Natural products are an important source for the discovery of pharmacologically active small molecules. However, little effort has been made in the discovery of synthetic lethal small molecules from natural products. This review introduces recent advances in the discovery of natural products targeting cancer cell dependency and discusses potentials of natural products in the precision cancer medicine.

C644-0303, a small-molecule inhibitor of the Wnt/β-catenin pathway, suppresses colorectal cancer growth

The Wnt/β‐catenin signaling pathway plays an important role in tissue homeostasis, and its malignant activation is closely related to the occurrence and development of many cancers, especially colorectal cancer with adenomatous polyposis coli (APC) and CTNNB1 mutations. By applying a TCF/lymphoid‐enhancing factor (LEF) luciferase reporter system, the high‐throughput screening of 18 840 small‐molecule compounds was performed. A novel scaffold compound, C644‐0303, was identified as a Wnt/β‐catenin signaling inhibitor and exhibited antitumor efficacy. It inhibited both constitutive and ligand activated Wnt signals and its downstream gene expression. Functional studies showed that C644‐0303 causes cell cycle arrest, induces apoptosis, and inhibits cancer cell migration. Moreover, transcription factor array indicated that C644‐0303 could suppress various tumor‐promoting transcription factor activities in addition to Wnt/β‐catenin. Finally, C644‐0303 suppressed tumor spheroidization in a 3‐dimensional cell culture model and inhibited xenograft tumor growth in mice. In conclusion, we report a novel structural small molecular inhibitor targeting the Wnt/β‐catenin signaling pathway that has therapeutic potential for colorectal cancer treatment.

Morphological neurite changes induced by porcupine inhibition are rescued by Wnt ligands

Background

Wnt signaling plays key roles in cellular and physiological processes, including cell proliferation, differentiation and migration during development and tissue homeostasis in adults. This pathway can be defined as Wnt/β-catenin-dependent or β-catenin-independent or “non-canonical”, both signaling are involved in neurite and synapse development/maintenance. Porcupine (PORCN), an acylase that o-acylates Wnt ligands, a major modification in secretion and interaction with its receptors. We use Wnt-C59, a specific PORCN inhibitor, to block the secretion of endogenous Wnts in embryonic hippocampal neurons (DIV 4). Under these conditions, the activity of exogenous Wnt ligands on the complexity of the dendritic tree and axonal polarity were evaluated

Methods

Cultured primary embryonic hippocampal neurons obtained from Sprague–Dawley rat fetuses (E18), were cultured until day in vitro (DIV) 4 (according to Banker´s protocol) and treated with Wnt-C59 for 24 h, Wnt ligands were added to the cultures on DIV 3 for 24 h. Dendritic arbors and neurites were analysis by fluorescence microscopy. Transfection with Lipofectamine 2000 on DIV 2 of plasmid expressing eGFP and KIF5-Cherry was carried out to evaluate neuronal polarity. Immunostaining was performed with MAP1B and Tau protein. Immunoblot analysis was carried out with Wnt3a, β-catenin and GSK-3β (p-Ser9). Quantitative analysis of dendrite morphology was carried out with ImageJ (NIH) software with Neuron J Plugin.

Results

We report, here, that Wnt-C59 treatment changed the morphology of the dendritic arbors and neurites of embryonic hippocampal neurons, with decreases β-catenin and Wnt3a and an apparent increase in GSK-3β (p-Ser9) levels. No effect was observed on axonal polarity. In sister cultures, addition of exogenous Wnt3a, 5a and 7a ligands rescued the changes in neuronal morphology. Wnt3a restored the length of neurites to near that of the control, but Wnt7a increased the neurite length beyond that of the control. Wnt5a also restored the length of neurites relative to Wnt concentrations.

Conclusions

Results indicated that Wnt ligands, added exogenously, restored dendritic arbor complexity in embryonic hippocampal neurons, previously treated with a high affinity specific Porcupine inhibitor. We proposed that PORCN is an emerging molecular target of interest in the search for preclinical options to study and treat Wnt-related diseases.

The Small Molecule BC-2059 Inhibits Wingless/Integrated (Wnt)-Dependent Gene Transcription in Cancer through Disruption of the Transducin β-Like 1-β-Catenin Protein Complex

The central role of β-catenin in the Wnt pathway makes it an attractive therapeutic target for cancers driven by aberrant Wnt signaling. We recently developed a small-molecule inhibitor, BC-2059, that promotes apoptosis by disrupting the β-catenin/transducin β-like 1 (TBL1) complex through an unknown mechanism of action. In this study, we show that BC-2059 directly interacts with high affinity for TBL1 when in complex with β-catenin. We identified two amino acids in a hydrophobic pocket of TBL1 that are required for binding with β-catenin, and computational modeling predicted that BC-2059 interacts at the same hydrophobic pocket. Although this pocket in TBL1 is involved in binding with NCoR/SMRT complex members G Protein Pathway Suppressor 2 (GSP2) and SMRT and p65 NFκB subunit, BC-2059 failed to disrupt the interaction of TBL1 with either NCoR/SMRT or NFκB. Together, our results show that BC-2059 selectively targets TBL1/β-catenin protein complex, suggesting BC-2059 as a therapeutic for tumors with deregulated Wnt signaling pathway. SIGNIFICANCE STATEMENT: This study reports the mechanism of action of a novel Wnt pathway inhibitor, characterizing the selective disruption of the transducin β-like 1/β-catenin protein complex. As Wnt signaling is dysregulated across cancer types, this study suggests BC-2059 has the potential to benefit patients with tumors reliant on this pathway.

Discovery of 1-Benzoyl 4-Phenoxypiperidines as Small-Molecule Inhibitors of the β-Catenin/B-Cell Lymphoma 9 Protein-Protein Interaction

Structure-based design and optimization were performed to develop small-molecule β-catenin/B-cell lymphoma 9 (BCL9) inhibitors and improve their inhibitory activities. Compound ZL3138 with a novel 1-benzoyl 4-phenoxypiperidine scaffold was discovered to disrupt the β-catenin/BCL9 protein-protein interaction (PPI) with a K_i of 0.96 μM in AlphaScreen competitive inhibition assays and displayed good selectivity for β-catenin/BCL9 over β-catenin/E-cadherin PPIs. The binding mode of new inhibitors was characterized by structure-activity relationship and site-directed mutagenesis studies. Protein pull-down assays indicate that this series of compounds directly binds with β-catenin. Cellular target engagement and co-immunoprecipitation experiments demonstrate that ZL3138 binds with β-catenin and disrupts the β-catenin/BCL9 interaction without affecting the β-catenin/E-cadherin interaction in living cells. Further cell-based studies show that ZL3138 selectively suppresses transactivation of Wnt/β-catenin signaling, regulates transcription and expression of Wnt target genes, and inhibits the growth of Wnt/β-catenin-dependent cancer cells.

γ-Oryzanol Improves Exercise Endurance and Muscle Strength by Upregulating PPARδ and ERRγ Activity in Aged Mice

SCOPE

γ-Oryzanol, a well-known antioxidant, has been used by body builders and athletes to boost strength and increase muscle gain, without major side effects. However, the effect of γ-Oryzanol on sarcopenia and the underlying molecular mechanism is poorly understood.

RESULTS

Aged mice fed with the γ-Oryzanol diet do not show significant changes in muscle weight, but show increased running endurance as well as improved grip strength. The expression and activity of PPARδ and ERRγ are increased in skeletal muscle of γ-Oryzanol supplemented mice. γ-Oryzanol upregulates oxidative muscle fibers by MEF2 transcription factor, and PGC-1α and ERRα expressions. Fatty acid oxidation related genes and mitochondria biogenesis are upregulated by γ-Oryzanol. In addition, γ-Oryzanol inhibits TGF-β-Smad-NADPH oxidase 4 pathway and inflammatory cytokines such as TNF-α, IL-1β, IL-6, and p65 NF-κB subunit, which cause skeletal muscle weakness. Collectively, γ-Oryzanol attenuates muscle weakness pathway and increases oxidative capacity by increasing PPARδ and ERRγ activity, which contributes to enhance strength and improve oxidative capacity in muscles, consequently enhancing exercise capacity in aged mice. Particularly, γ-Oryzanol directly binds to PPARδ.

CONCLUSIONS

These are the first findings showing that γ-Oryzanol enhances skeletal muscle function in aged mice by regulating PPARδ and ERRγ activity without muscle gain.

miR-20a/TCF4 axis-mediated inhibition of hepatocytes proliferation impairs liver regeneration in mice PHx model by regulating CDC2 and CDC6

MicroRNAs have emerged as essential regulators in the biological process of liver regeneration by modulating the post‐transcriptional expression of the target genes. In the present study, we found miR‐20a expression is decreased remarkably in three rodent liver regeneration models using miRNA PCR array and Venn diagram analysis. Inhibition of miR‐20a expression enhanced hepatocytes proliferation in vivo and in vitro. In contrast, overexpression of miR‐20a reduces hepatocytes proliferation and subsequently impaired liver regeneration in the mouse PHx model. Moreover, we have identified TCF4 as a target gene of miR‐20a using the PCR Array and luciferase assay. Next, mice with TCF4 deficiency were used to establish the PHx model and subjected to the examination of liver regeneration capacity. We found TCF4‐deficient mice exhibited impaired liver regeneration compared with control. Given that TCF4 acts as a transcription factor, we sort to elucidate the downstream genes involved in liver regeneration. Promoter analysis and Chip assay confirmed that TCF4 enhances CDC2 and CDC6 expression through binding to the promoter region and leads to the proliferation and cell cycle progression in hepatocytes. In conclusion, this study provides evidence that the miR20a‐TCF4‐CDC2/6 axis plays an essential role during liver regeneration.

ACBP suppresses the proliferation, migration, and invasion of colorectal cancer via targeting Wnt/beta-catenin signaling pathway

Anticancer bioactive peptide (ACBP), a novel bioactive peptide isolated from spleens of goats immunized with tumor extracts in our lab, can inhibit the proliferation of CRC in vitro and vivo. However, it remains unclear how the proliferation of CRC is inhibited by ACBP at the molecular level. Here, we provide evidences showing that ACBP significantly inhibits the expression of Wnt/β-catenin related genes (cyclin D1, met and c-myc) through pharmacotranscriptomic and qRT-PCR analysis in CRCs. Active β-catenin, a key protein within Wnt pathway, was compromised remarkably by ACBP in three CRCs, including HCT116, RKO and HT29. Thus nuclear accumulation of active β-catenin was retarded and finally lead to the decreased expression of oncogenes cyclin D1, met, and c-myc. In addition, we proved that active β-catenin reduction was mainly due to the inhibition of phospho-LRP6 and stimulation of phospho-β-catenin by ACBP. Based on the detection of Met and C-Myc in CRC tumor tissue without prior radiotherapy or chemotherapy, our results demonstrated that ACBP can act as a promising anticancer agent for CRC by targeting Wnt/β-catenin pathway, especially active β-catenin.

Direct targeting of β-catenin in the Wnt signaling pathway: Current progress and perspectives

Aberrant activation of the Wnt/β-catenin signaling circuit is associated with cancer recurrence and relapse, cancer invasion and metastasis, and cancer immune evasion. Direct targeting of β-catenin, the central hub in this signaling pathway, is a promising strategy to suppress the hyperactive β-catenin signaling but has proven to be highly challenging. Substantial efforts have been made to discover compounds that bind with β-catenin, block β-catenin-mediated protein-protein interactions, and suppress β-catenin signaling. Herein, we characterize potential small-molecule binding sites in β-catenin, summarize bioactive small molecules that directly target β-catenin, and review structure-based inhibitor optimization, structure-activity relationship, and biological activities of reported inhibitors. This knowledge will benefit future inhibitor development and β-catenin-related drug discovery.

A perspective on medicinal chemistry approaches towards adenomatous polyposis coli and Wnt signal based colorectal cancer inhibitors

Colorectal cancer (CRC) is one of the major causes of carcinogenic mortality in numbers only after lung and breast cancers. The mutations in adenomatous polyposis coli (APC) gene leads to formation of colorectal polyps in the colonic region and which develop as a malignant tumour upon coalition with patient related risk factors. The protein-protein interaction (PPI) of APC with Asef (A Rac specific guanine nucleotide exchange factor) overwhelms the patient's conditions by rapidly spreading in the entire colorectal region. Most mutations in APC gene occur in mutated cluster region (MCR), where it specifically binds with the cytosolic β-catenin to regulate the Wnt signalling pathway required for CRC cell adhesion, invasion, progression, differentiation and stemness in initial cell cycle phages. The current broad spectrum perspective is attempted to elaborate the sources of identification, development of selective APC inhibitors by targeting emopamil-binding protein (EBP) & dehydrocholesterol reductase-7 & 24 (DHCR-7 & 24); APC-Asef, β-catenin/APC, Wnt/β-catenin, β-catenin/TCF4 PPI inhibitors with other vital Wnt signal cellular proteins and APC/Pol-β interface of colorectal cancer. In this context, this perspective would serve as a platform for design of new medicinal agents by targeting cellular essential components which could accelerate anti-colorectal potential candidates.

Identification of afzelin potential targets in inhibiting triple-negative breast cancer cell migration using reverse docking

BACKGROUND

Triple-negative breast cancer (TNBC) tends to be aggressive and metastatic, characteristics attributable to its cellular migration capabilities. Afzelin is a chemical compound with anti-metastatic potentials. This study aimed to predict proteins involved in TNBC cell migration which could be inhibited by afzelin.

METHODS

The protein database was constructed from the Kyoto Encyclopedia of Genes and Genomes pathways collection which related to cell motility, then screened for druggability using SuperTarget and Therapeutic Target Database. The involvement of druggable proteins in the TNBC metastasis process was investigated through existing publications in The National Center for Biotechnology Information PubMed database. Inhibitory potential of afzelin toward target proteins was compared to the proteins' known-inhibitor, using the reverse docking method.

RESULTS

Ten proteins identified as potential targets of afzelin, with the top 3 being ERK2, KRas, and FAK, respectively. Afzelin's 3-O-rhamnoside group played a dominant role in forming hydrogen bonds with the target proteins. Further analysis with STRING suggested that afzelin might be able to inhibit chemotaxis and haptotaxis of TNBC cells.

CONCLUSIONS

Afzelin was predicted to inhibit TNBC cell motility, by targeting ERK2, KRas, and FAK activation.

Transcriptional Regulation of Wnt/β-Catenin Pathway in Colorectal Cancer

The Wnt/β-catenin signaling pathway exerts integral roles in embryogenesis and adult homeostasis. Aberrant activation of the pathway is implicated in growth-associated diseases and cancers, especially as a key driver in the initiation and progression of colorectal cancer (CRC). Loss or inactivation of Adenomatous polyposis coli (APC) results in constitutive activation of Wnt/β-catenin signaling, which is considered as an initiating event in the development of CRC. Increased Wnt/β-catenin signaling is observed in virtually all CRC patients, underscoring the importance of this pathway for therapeutic intervention. Prior studies have deciphered the regulatory networks required for the cytoplasmic stabilisation or degradation of the Wnt pathway effector, β-catenin. However, the mechanism whereby nuclear β-catenin drives or inhibits expression of Wnt target genes is more diverse and less well characterised. Here, we describe a brief synopsis of the core canonical Wnt pathway components, set the spotlight on nuclear mediators and highlight the emerging role of chromatin regulators as modulators of β-catenin-dependent transcription activity and oncogenic output.

The Canonical Wnt Signaling (Wnt/β-Catenin Pathway): A Potential Target for Cancer Prevention and Therapy

Precise regulation of signal transduction pathways is crucial for normal animal development and for maintaining cellular and tissue homeostasis in adults. The Wnt/Frizzled-mediated signaling includes canonical and non-canonical signal transduction pathways. Upregulation or downregulation of the canonical Wnt signaling (or the Wnt/β-Catenin signal transduction) leads to a variety of human diseases, including cancers, neurodegenerative disorders, skin and bone diseases, and heart deficiencies. Therefore, Wnt/β-Catenin signal transduction is a potential clinical target for the treatment of not only human cancers but also some other human chronic diseases. Here, some recent results including those from my laboratory highlighting the role of Wnt/β-Catenin signal transduction in human cancers will be reviewed. After a brief overview on canonical Wnt signaling and introducing some critical β-Catenin/T-cell factor-target genes, the interaction of canonical Wnt signaling with some common human cancers will be discussed. In the end, the different segments of the aforesaid signaling pathway, which have been considered as targets for clinical purposes, will be scrutinized.

β-Catenin: oncogenic role and therapeutic target in cervical cancer

Cervical cancer is a common and fatal malignancy of the female reproductive system. Human papillomavirus (HPV) is the primary causal agent for cervical cancer, but HPV infection alone is insufficient to cause the disease. Actually, most HPV infections are sub-clinical and cleared spontaneously by the host immune system; very few persist and eventually develop into cervical cancer. Therefore, other host or environmental alterations could also contribute to the malignant phenotype. One of the candidate co-factors is the β-catenin protein, a pivotal component of the Wnt/β-catenin signaling pathway. β-Catenin mainly implicates two major cellular activities: cell–cell adhesion and signal transduction. Recent studies have indicated that an imbalance in the structural and signaling properties of β-catenin leads to various cancers, such as cervical cancer. In this review, we will systematically summarize the role of β-catenin in cervical cancer and provide new insights into therapeutic strategies.

Lactobacillus reuteri Promotes Intestinal Development and Regulates Mucosal Immune Function in Newborn Piglets

Intestinal microbiota is necessary for the guarantee of intestinal mucosal barrier. However, the detailed effect of probiotics on porcine intestinal development, especially in the early life, is still unclear. In this study, we treated 3-day-old newborn piglets with Lactobacillus reuteri (L. reuteri) D8 and observed its beneficial effect on piglets. The body weights, villus height, and crypt depth of jejunum were all significantly increased after L. reuteri treatment in piglets. L. reuteri also significantly increased the proliferation index of PCNA⁺ cells in the crypt, as well as c-Myc and Tcf4 expressions. Furthermore, L. reuteri also enhanced intestinal mucosal barrier with the increase of goblet cells and antimicrobial peptides (AMPs) expressions of Muc2, Lyz1, and pBD1. The well development of Peyer's patches and increased number of CD3⁺ T cells, combined with increased expression of IL-4 and IFN-γ, also demonstrated the immune stimulation effect of L. reuteri D8. This study demonstrated that L. reuteri promotes the development of intestine mucosal system and maintains intestinal mucosal barrier in newborn piglets.

An engineered antibody fragment targeting mutant β-catenin via major histocompatibility complex I neoantigen presentation

Mutations in CTNNB1, the gene encoding β-catenin, are common in colon and liver cancers, the most frequent mutation affecting Ser-45 in β-catenin. Peptides derived from WT β-catenin have previously been shown to be presented on the cell surface as part of major histocompatibility complex (MHC) class I, suggesting an opportunity for targeting this common driver gene mutation with antibody-based therapies. Here, crystal structures of both the WT and S45F mutant peptide bound to HLA-A*03:01 at 2.20 and 2.45 Å resolutions, respectively, confirmed the accessibility of the phenylalanine residue for antibody recognition. Phage display was then used to identify single-chain variable fragment clones that selectively bind the S45F mutant peptide presented in HLA-A*03:01 and have minimal WT or other off-target binding. Following the initial characterization of five clones, we selected a single clone, E10, for further investigation. We developed a computational model of the binding of E10 to the mutant peptide-bound HLA-A3, incorporating data from affinity maturation as initial validation. In the future, our model may be used to design clones with maintained specificity and higher affinity. Such derivatives could be adapted into either cell-based (CAR-T) or protein-based (bispecific T-cell engagers) therapies to target cancer cells harboring the S45F mutation in CTNNB1.

Effects of Laminaria Japonica Polysaccharides on the Survival of Non-Small-Cell Lung Cancer A549 Cells

Objective. To investigate the effect of Laminaria japonica polysaccharides (LJP) on the survival of non-small-cell lung cancer (NSCLC) A549 cells and its mechanism. Methods. In vitro: the cells were randomly divided into control group, LJP (5 mg/ml) group, LJP (10 mg/ml) group, and LJP (20 mg/ml) group. After corresponding treatment, the survival rate and the expression of proteins related to proliferation, apoptosis, epithelial-mesenchymal transition (EMT), and signaling pathway were detected by CCK8 assay and Western blot, respectively. In vivo: a xenograft model was established to detect the tumor volume and mass and the expression of the above pathway proteins. Results. Compared with the control group, LJP decreased the survival rate of A549 cells (P<0.05), inhibited the protein expression of Ki67 and PCNA (P<0.05), downregulated the expression of Bcl-2 while upregulated the expression of Bax, cl-caspase-3, and cl-caspase-9 (P<0.05), upregulated the expression of E-cadherin, downregulated the expression of vascular endothelial growth factor (VEGF) and N-cadherin (P<0.05), and downregulated β-catenin, transcription factor-4 (TCF4), and c-Myc protein expression levels (P<0.05). In vivo: LJP decreased the volume and mass of the xenograft tumors and downregulated β-catenin, TCF4, and c-Myc protein expression levels compared with the control group (P<0.05). Conclusion. LJP can inhibit the survival of non-small-cell lung cancer A549 cells in vitro, and its mechanism is related to the inhibition of activation of β-catenin/TCF4 pathway activation.

circGSK3β promotes metastasis in esophageal squamous cell carcinoma by augmenting β-catenin signaling

Background

Circular RNAs (circRNAs), a novel class of noncoding RNAs, have recently drawn much attention in the pathogenesis of human cancers. However, the role of circRNAs in esophageal squamous cell carcinoma (ESCC) remains unclear. In this study, we aimed to identify novel circRNAs that regulate ESCC progression and explored their regulatory mechanisms and clinical significance in ESCC.

Methods

Differentially expressed circRNAs between ESCC and paired adjacent normal tissues were identified using microarrays. The effects of a specific differentially expressed circRNA (circGSK3β) on tumor progression were explored in vitro and in vivo. Plasma samples from patients with ESCC, benign lesions and healthy controls were subjected to droplet digital PCR (ddPCR) analyses for circGSK3β, and the detection rates of plasma circGSK3β for ESCC were investigated.

Results

We demonstrated that upregulated expression of circGSK3β was positively associated with advanced clinical stage and poor outcome in patients with ESCC. We further revealed that circGSK3β promoted ESCC cell migration and invasion via direct interaction with GSK3β and inhibiting GSK3β activity, providing a novel mechanism of circRNA in cancer progression. Importantly, we identified that circGSK3β expression in plasma was a biomarker for detection of ESCC and early stage of ESCC with the area under curve (AUC) of 0.782 and 0.793, respectively.

Conclusions

CircGSK3β exerts critical roles in promoting ESCC metastasis and may serve as a novel therapeutic target for ESCC patients. The plasma level of circGSK3β have potential to serve as a novel diagnostic and prognostic biomarker for ESCC detection.

A small-molecule LF3 abrogates β-catenin/TCF4-mediated suppression of NaV1.5 expression in HL-1 cardiomyocytes

Increased nuclear β-catenin interacting with T-cell factor 4 (TCF4) affects the expression of target genes including SCN5A in ischemic heart disease, which is characterized by frequent ventricular tachycardia/fibrillation. A complex of β-catenin and TCF4 inhibits cardiac Na+ channel activity by reducing NaV1.5 expression through suppressing SCN5A promoter activity in HL-1 cardiomyocytes. LF3, a 4-thioureido-benzenesulfonamide derivative and an inhibitor of β-catenin/TCF4 interaction, has been shown to block the self-renewal capacity of cancer stem cells. We performed studies to determine if LF3 can reverse suppressive effects of β-catenin/TCF4 signaling on the expression of NaV1.5 in HL-1 cardiomyocytes. Western blotting and real-time qRT-PCR analyses showed that 10 μM LF3 significantly increased the expression of NaV1.5 but it did not alter β-catenin and TCF4 expression. Subcellular fractionation analysis demonstrated that LF3 significantly increased the levels of NaV1.5 in both membrane and cytoplasm. Whole-cell patch-clamp recordings revealed that Na+ currents were significantly increased with no changes in the steady-state parameters, activation and inactivation time constants and recovery from inactivation of Na+ channel in HL-1 cells treated with LF3. Immunoprecipitation exhibited that LF3 blocked the interaction of β-catenin and TCF4. Luciferase reporter assays performed in HEK 293 cells and HL-1 revealed that LF3 increased the SCN5A promoter activity in HL-1 cells and prevented β-catenin suppressive effect on SCN5A promoter activity in HEK 293 cells. Taken together, we conclude that LF3, an inhibitor of β-catenin/TCF4 interaction, elevates NaV1.5 expression, leading to increase Na+ channel activity in HL-1 cardiomyocytes.

Targeting transcription factor TCF4 by γ-Mangostin, a natural xanthone

Given that colon cancer is the third most common cancer in incidence and cause of death in the United States, and current treatment modalities are insufficient, there is a need to develop novel agents. Towards this, here we focus on γ-Mangostin, a bioactive compound present in the Mangosteen (Garcinia mangostana) fruit. γ-Mangostin suppressed proliferation and colony formation, and induced cell cycle arrest and apoptosis of colon cancer cell lines. Further, γ-Mangostin inhibited colonosphere formation. Molecular docking and CETSA (Cellular thermal shift assay) binding assays demonstrated that γ-Mangostin interacts with transcription factor TCF4 (T-Cell Factor 4) at the β-catenin binding domain with the binding energy of -5.5 Kcal/mol. Moreover, γ-Mangostin treatment decreased TCF4 expression and reduced TCF reporter activity. The compound also suppressed the expression of Wnt signaling target proteins cyclin D1 and c-Myc, and stem cell markers such as LGR5, DCLK1 and CD44. To determine the effect of γ-Mangostin on tumor growth in vivo, we administered nude mice harboring HCT116 tumor xenografts with 5 mg/Kg of γ-Mangostin intraperitoneally for 21 days. γ-Mangostin treatment significantly suppressed tumor growth, with notably lowered tumor volume and weight. In addition, western blot analysis revealed a significant decrease in the expression of TCF4 and its downstream targets such as cyclin D1 and c-Myc. Together, these data suggest that γ-Mangostin inhibits colon cancer growth through targeting TCF4. γ-Mangostin may be a potential therapeutic agent for colon cancer.

Nek2B activates the wnt pathway and promotes triple-negative breast cancer chemothezrapy-resistance by stabilizing β-catenin

Background

The chemotherapy-resistance of triple-negative breast cancer (TNBC) remains a major challenge. The Nek2B kinase and β-catenin serve as crucial regulators of mitotic processes. The aim of this study was to test the correlation between Nek2B and TNBC chemotherapy sensitivity, and to determine the regulation of Nek2B on β-catenin and wnt/β-catenin signal pathway.

Methods

Gene Expression Omnibus(GEO) databases were used to gather gene exprsssion data of TNBC patients who undergoing chemotherapy. The co-expression of Nek2B and β-catenin in TNBC surgical sections and cells were analysed by immunohistochemistry, Q-RT-PCR, Western-blot and immunofluorescent staining. The impact of the expression of Nek2B and β-catenin in prognosis was also assessed using the Kaplan-Meier curves. CCK8 assay was used to detect the IC50 value of TNBC cell line. The endogenous binding capacity of Nek2B and β-catenin and phosphorylation of β-catenin by Nek2B were detected using co-immunoprecipitation (CO-IP). Chromatin immune-precipitation (ChIP) analysis and Luciferase Assays were used to evaluate the binding ability of the Nek2B, β-catenin and TCF4 complex with LEF-1 promoter. Nek2B-siRNA and Nek2B plasmid were injected into nude mice, and tumorigenesis was monitored.

Results

We found that overexpression of Nek2B and β-catenin in TNBC samples, was associated with patients poor prognosis. Patients with positive Nek2B expression were less sensitive to paclitaxel-containing neoadjuvant chemotherapy. Interestingly, in a panel of established TNBC cell line, Nek2B and β-catenin were highly expressed in cells exhibiting paclitaxel resistance. Our data also suggest that β-catenin binded to and was phosphorylated by Nek2B, and was in a complex with TCF4. Nek2B mainly regulates the expression of β-catenin in TNBC nucleus. Nek2B, β-catenin and TCF4 can be binded with the WRE functional area of LEF-1 promoter. Nek2B can activite wnt signaling pathway and wnt downstream target genes. The tumors treated by Nek2B siRNA associated with paclitaxel were the smallest in nude mouse, and Nek2B can regulate the expression of β-catenin and wnt downstream target genes in vivo.

Conclusion

Our study suggested that Nek2B can bind to β-catenin and the co-expression correlated with TNBC patients poor prognosis. It appears that Nek2B and β-catenin might synergize to promote chemotherapy resistance.

Inhibition of LTA4H by bestatin in human and mouse colorectal cancer

Background

Our preclinical data showed that the leukotriene A4 hydrolase (LTA4H) pathway plays a role in colorectal cancer (CRC). High expression of LTA4H and leukotriene B4 receptor type 1 (BLT1) were also associated with CRC survival probability. Clinical samples were evaluated to determine whether LTA4H could serve as a therapeutic target and whether leukotriene B4 (LTB4) could be used as a biomarker for evaluating the efficacy of bestatin in CRC.

Methods

Patients with Stage I-III CRC did or did not receive bestatin prior to surgery. Evaluable pairwise CRC patient blood samples were collected to evaluate LTB4 concentration. Tissues were processed by immunohistochemistry to detect the LTA4H pathway and Ki-67 expression. We also determined whether LTA4H or BLT1 was associated with CRC survival probability and explored the mechanism of bestatin action in CRC.

Findings

Samples from 13 CRC patients showed a significant decrease in LTB4, the LTA4H signaling pathway, and Ki-67 in the bestatin-treated group compared with the untreated group. LTA4H and BLT1 are overexpressed in CRC and associated with CRC survival probability. Bestatin effectively inhibited LTB4 and tumorigenesis in the Apc^Min/+ and CRC patient-derived xenograft mouse model.

Interpretation

These results demonstrate that LTB4 could serve as a biomarker for evaluating bestatin efficacy in CRC and the antitumor effects of bestatin through its targeting of LTA4H and support further studies focusing on LTA4H inhibition in CRC.

Optimization of Peptidomimetics as Selective Inhibitors for the β-Catenin/T-Cell Factor Protein-Protein Interaction

The β-catenin/T-cell factor (Tcf) protein-protein interaction (PPI) plays a critical role in the β-catenin signaling pathway which is hyperactivated in many cancers and fibroses. Based on compound 1, which was designed to target the Tcf4 G¹³ANDE¹⁷ binding site of β-catenin, extensive structure-activity relationship studies have been conducted. As a result, compounds 53 and 57 were found to disrupt the β-catenin/Tcf PPI with the K_i values of 0.64 and 0.44 μM, respectively, and exhibit good selectivity for β-catenin/Tcf over β-catenin/E-cadherin and β-catenin/adenomatous polyposis coli (APC) PPIs. The 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2 H-tetrazolium (MTS) cell viability assays revealed that 56, the ethyl ester of 53, was more potent than 53 in inhibiting viability of most of the Wnt/β-catenin hyperactive cancer cells. Further cell-based studies indicated that 56 disrupted the β-catenin/Tcf PPI without affecting the β-catenin/E-cadherin and β-catenin/APC PPIs, suppressed transactivation of Wnt/β-catenin signaling in dose-dependent manners, and inhibited migration and invasiveness of Wnt/β-catenin-dependent cancer cells.

TET1 suppresses colon cancer proliferation by impairing β-catenin signal pathway

The function of ten-eleven translocation methylcytosine dioxygenase 1 (TET1) in cancer is background dependent and may be involved in the initial step of active DNA demethylation, while there is little research to decipher the role of TET1 in DNA methylation-sensitive colon cancer. Downregulated TET1 expression assayed by quantitative real-time PCR (qRT-PCR) was observed in both colon cancer samples and cancer cell lines of HT29, HCT116, and SW48. Such downregulation could promote colon cancer cells proliferation as indicated by the fact that shTET1 could increase the viability of HT29 and HCT116 cells determined by the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide and cell count assay accompanied with upregulation of β-catenin (CTNNB1) and WNT luciferase activity, which was further confirmed as shTET1 could increase the tumor volume and tumor weight, and decrease the body weight in HT29 cells inoculated BALB/C nude mice. The CTNNB1 transfection could rescue the cell growth diminished by normal expression of TET1. shTET1 could promote axis inhibition protein1 (AXIN1) expression and the cell proliferation effect induced by TET1 short hairpin RNA was attenuated by co-inhibition of AXIN1. All of these indicate that TET1 can suppress colon cancer proliferation and the inhibition of the β-catenin pathway is AXIN1 dependent.

Human telomerase reverse transcriptase recruits the β-catenin/TCF-4 complex to transactivate chemokine (C-C motif) ligand 2 expression in colorectal cancer

BACKGROUND AND AIM

Various molecular mechanisms are involved in the pathogenesis of colorectal cancer (CRC), one of the leading fatal diseases. Although human telomerase reverse transcriptase (hTERT) is critical in promoting CRC development, its regulatory mechanism is still elusive. Chemokine (C-C motif) ligand 2 (CCL2) is important to CRC pathogenesis, but the upstream regulation of CCL2 requires further investigation. Therefore, we aim to investigate the crosstalk mechanism between hTERT and CCL2 and its involvement in the pathogenesis of CRC.

METHODS

The expression relationship between hTERT and CCL2 was verified in CRC and adjacent tissues by immunohistochemistry. Lentiviruses or plasmids were used to regulate hTERT and CCL2 expression. The roles of hTERT and CCL2 in cell growth and migration were studied using CCK8 and transwell assays. The interaction between hTERT and CCL2 was detected by a luciferase reporter assay, immunofluorescence and ChIP assays. The β-catenin/TCF-4 complex was confirmed by COIP.

RESULTS

Both hTERT and CCL2 expression levels were markedly increased in CRC tissues compared to the adjacent stroma. Moreover, myeloid-derived suppressor cells (MDSCs) were found in tumor areas with higher expression levels of hTERT and CCL2. hTERT promoted HCT116 cell migration and invasion by increasing CCL2 expression. Mechanistically, ectopic hTERT facilitated the nuclear translocation of canonical β-catenin and the formation of a complex with downstream effector TCF-4, which eventually activated the CCL2 promoter.

CONCLUSIONS

hTERT may promote CRC by recruiting β-catenin/TCF-4 complex to transactivate CCL2 expression, which is a novel crosstalk mechanism likely involved in the pathogenesis of CRC.

Therapeutic potential of targeting the Wnt/β-catenin signaling pathway in colorectal cancer

Aberrant Wnt/β-catenin signaling has often been reported in different cancers, particularly colorectal cancer (CRC), and this signaling cascade is central to carcinogenesis. Approximately 80% of CRC cases harbor mutations in the adenomatous polyposis coli gene, and half of the remaining cases feature mutations in the β-catenin gene that affect the Wnt/β-catenin signaling pathway. Unsurprisingly, the Wnt/β-catenin signaling pathway has potential value as a therapeutic target in the treatment of CRC. Several inhibitors of the Wnt/β-catenin signaling pathway have been developed for CRC treatment, but so far no molecular therapeutic targeting this pathway has been incorporated into oncological practice. In this review, we discuss the role of Wnt/β-catenin signaling in CRC and its potential as a target of innovative therapeutic approaches for CRC.

Potential signaling pathways as therapeutic targets for overcoming chemoresistance in mucinous ovarian cancer

Cases of mucinous ovarian cancer are predominantly resistant to chemotherapies. The present review summarizes current knowledge of the therapeutic potential of targeting the Wingless (WNT) pathway, with particular emphasis on preclinical and clinical studies, for improving the chemoresistance and treatment of mucinous ovarian cancer. A review was conducted of English language literature published between January 2000 and October 2017 that concerned potential signaling pathways associated with the chemoresistance of mucinous ovarian cancer. The literature indicated that aberrant activation of growth factor and WNT signaling pathways is specifically observed in mucinous ovarian cancer. An evolutionarily conserved signaling cascade system including epidermal growth factor/RAS/RAF/mitogen-activated protein kinase kinase/extracellular signal-regulated protein kinase, phosphoinositide 3-kinase/Akt and WNT signaling regulates a variety of cellular functions; their crosstalk mutually enhances signaling activity and induces chemoresistance. Novel antagonists, modulators and inhibitors have been developed for targeting the components of the WNT signaling pathway, namely Frizzled, low-density lipoprotein receptor-related protein 5/6, Dishevelled, casein kinase 1, AXIN, glycogen synthase kinase 3β and β-catenin. Targeted inhibition of WNT signaling represents a rational and promising novel approach to overcome chemoresistance, and several WNT inhibitors are being evaluated in preclinical studies. In conclusion, the WNT receptors and their downstream components may serve as novel therapeutic targets for overcoming chemoresistance in mucinous ovarian cancer.