Discovery of chemical probes that suppress Wnt/β-catenin signaling through high-throughput screening

Targeting the Wnt/β-catenin signal pathway for the treatment of gastrointestinal cancer: Potential for advancement

Gastrointestinal cancers (GICs) are highly prevalent cancers that threaten human health worldwide. The Wnt/β-catenin signaling pathway has been reported to play a pivotal role in the carcinogenesis of GICs. Numerous interventions targeting the Wnt/β-catenin signaling in GICs are currently being tested in clinical trials with promising results. Unfortunately, there are no clinically approved drugs that effectively target this pathway. This comprehensive review aims to evaluate the impact of clinical therapies targeting the Wnt/β-catenin signaling pathway in GICs. By integrating data from bioinformatics databases and recent literature from the past five years, we examine the heterogeneous expression and regulatory mechanisms of Wnt/β-catenin pathway genes and proteins in GICs. Specifically, we focus on expression patterns, mutation frequencies, and clinical prognoses to understand their implications for treatment strategies. Additionally, we discuss recent clinical trial efforts targeting this pathway. Understanding the inhibitors currently under clinical investigation may help optimize foundational research and clinical strategies. We hope that elucidating the current status of precision therapeutic stratification for patients targeting the Wnt/β-catenin pathway will guide future innovations in precision medicine for GICs.

Pyrogallol promotes growth arrest by activating the p53-mediated up-regulation of p21 and p62/SQSTM1-dependent degradation of β-catenin in nonsmall cell lung cancer cells

Pyrogallol (1,2,3-trihydroxybenzene), a polyphenolic natural compound, has attracted considerable attention with regard to its potential anticancer activity. However, further study is needed to elucidate the underlying mechanism related to the antiNSCLC activity of pyrogallol and provide a comprehensive theoretical basis for better clinical utilization of pyrogallol. Our current study aims to investigate the effects and potential underlying mechanisms of pyrogallol on the inhibition of NSCLC growth. Our results showed that pyrogallol treatment induced cell cycle arrest at the G2/M phase and apoptosis in two different NSCLC cell lines. Mechanistically, we found that the induction of cell cycle arrest in NSCLC cells at the G2/M phase by pyrogallol was due to the upregulation of p21 in a p53-dependent manner. And blockade of p53 and p21 effectively abolished the cell cycle arrest at the G2/M phase. Meanwhile, p53 inhibition has been found to abrogate the pyrogallol-induced apoptosis of the two NSCLC cells. Moreover, we revealed that the inhibitory effects of pyrogallol on β-catenin signaling resulted from autophagy initiation depending on p53 activation, accompanied by an increase in p62/SQSTM1 expression, thus p62 subsequently interacting with ubiquitinated β-catenin and facilitating autophagic destruction of β-catenin. Furthermore, in vivo experiments demonstrated that pyrogallol exerted growth inhibition on NSCLC with low toxicity through the same molecular mechanism as observed in vitro. Our findings could contribute to the understanding of the mechanism by which pyrogallol negatively regulates NSCLC growth, which could be effective in treating NSCLC.

Cis-regulatory control of mammalian Trps1 gene expression

TRPS1 serves as the causative gene for tricho-rhino phalangeal syndrome, known for its craniofacial and skeletal abnormalities. The Trps1 gene encodes a protein that represses Wnt signaling through strong interactions with Wnt signaling inhibitors. The identification of genomic cis-acting regulatory sequences governing Trps1 expression is crucial for understanding its role in embryogenesis. Nevertheless, to date, no investigations have been conducted concerning these aspects of Trps1. To identify deeply conserved noncoding elements (CNEs) within the Trps1 locus, we employed a comparative genomics approach, utilizing slowly evolving fish such as coelacanth and spotted gar. These analyses resulted in the identification of eight CNEs in the intronic region of the Trps1 gene. Functional characterization of these CNEs in zebrafish revealed their regulatory potential in various tissues, including pectoral fins, heart, and pharyngeal arches. RNA in-situ hybridization experiments revealed concordance between the reporter expression pattern induced by the identified set of CNEs and the spatial expression pattern of the trps1 gene in zebrafish. Comparative in vivo data from zebrafish and mice for CNE7/hs919 revealed conserved functions of these enhancers. Each of these eight CNEs was further investigated in cell line-based reporter assays, revealing their repressive potential. Taken together, in vivo and in vitro assays suggest a context-dependent dual functionality for the identified set of Trps1-associated CNE enhancers. This functionally characterized set of CNE-enhancers will contribute to a more comprehensive understanding of the developmental roles of Trps1 and can aid in the identification of noncoding DNA variants associated with human diseases.

Sinensetin suppresses breast cancer cell progression via Wnt/β-catenin pathway inhibition

Background

Although there are many treatments for breast cancer, such as surgery, radiotherapy, chemotherapy, estrogen receptor antagonists, immune checkpoint inhibitors and so on. However, safer and more effective therapeutic drugs for breast cancer are needed. Sinensetin, a safer therapeutic drugs, come from citrus species and medicinal plants used in traditional medicine, while its role and underlying mechanism in breast cancer remain unclear. Our study aimed to investigate the role and mechanism of sinensetin in breast cancer.

Methods

Cell Counting Kit-8 (CCK-8) was used to determine the safe concentration of sinensetin in MCF-10A, MCF7 and MDA-MB-231 cells; 120 μM sinensetin was used in subsequent experiments. Real time polymerase chain reaction (RT-PCR), Western blotting, Terminal Deoxynucleotidyl Transferase mediated dUTP Nick-End Labeling (TUNEL) apoptosis assay, Transwell invasion assay and Clone formation assay were used in this study to determine cell viability, mRNA expression, protein levels, apoptosis, proliferation, invasion and so on.

Results

Herein, our results showed that 120 μM sinensetin suppressed the cell viability and promoted apoptosis of MCF7 and MDA-MB-231 cells. Treatment with 120 µM sinensetin for 24 h showed no significant toxicity to normal mammary cells; 120 μM sinensetin decreased cell proliferation, invasion, and epithelial-mesenchymal transition (EMT), and downregulated β-catenin, lymphatic enhancing factor 1 (LEF1), T-cell factor (TCF) 1/TCF7, and TCF3/TCF7L1 expression in MCF7 and MDA-MB-231 cells. The Wnt agonist SKL2001 reversed the inhibitory effect of sinensetin on cell survival, metastasis, and EMT. Sinensetin-induced downregulation of β-catenin, LEF1, and TCF1/TCF7 expression were upregulated by SKL2001 in MCF7 and MDA-MB-231 cells.

Conclusions

In summary, sinensetin suppressed the metastasis of breast cancer cell via inhibition of Wnt/β-catenin pathway and there were no adverse effects on normal breast cells. Our study confirmed the role of sinensetin in breast cancer cells and provided a better understanding of the underlying mechanism.

Discovery of tetrazolo-pyridazine-based small molecules as inhibitors of MACC1-driven cancer metastasis

Metastasis is directly linked to poor prognosis of cancer patients and warrants search for effective anti-metastatic drugs. MACC1 is a causal key molecule for metastasis. High MACC1 expression is prognostic for metastasis and poor survival. Here, we developed novel small molecule inhibitors targeting MACC1 expression to impede metastasis formation. We performed a human MACC1 promoter-driven luciferase reporter-based high-throughput screen (HTS; 118.500 compound library) to identify MACC1 transcriptional inhibitors. HTS revealed 1,2,3,4-tetrazolo[1,5-b]pyridazine-based compounds as efficient transcriptional inhibitors of MACC1 expression, able to decrease MACC1-induced cancer cell motility in vitro. Structure-activity relationships identified the essential inhibitory core structure. Best candidates were evaluated for metastasis inhibition in xenografted mouse models demonstrating metastasis restriction. ADMET showed high drug-likeness of these new candidates for cancer therapy. The NFκB pathway was identified as one mode of action targeted by these compounds. Taken together, 1,2,3,4-tetrazolo[1,5-b]pyridazine-based compounds are effective MACC1 inhibitors and pose promising candidates for anti-metastatic therapies particularly for patients with MACC1-overexpressing cancers, that are at high risk to develop metastases. Although further preclinical and clinical development is necessary, these compounds represent important building blocks for an individualized anti-metastatic therapy for solid cancers.

Aberrant Expression of β-Catenin Correlates with Infiltrating Immune Cells and Prognosis in NSCLC

Aims: β-catenin is a critical regulating factor of the Wnt pathway, which is closely linked to tumorigenesis, tumor growth, metastasis, and tumor immunity. Our study focused on exploring the relationship between β-catenin and clinicopathological features, prognosis, as well as infiltrating immune cells and immune scores, so as to illustrate its clinical significance in NSCLC. Materials and Methods: The β-catenin mRNA (CTNNB1) and protein expression data were downloaded from the UALCAN and the UCSC Xena website, respectively. All tumor-immune infiltrating cells' data were downloaded from the TIMER platform and immune scores were downloaded from ESTIMATE website. The expression of β-catenin protein in our cohort was measured by immunohistochemistry. Results: β-catenin mRNA level was higher in lung adenocarcinoma (LUAD) compared to normal tissues (p < 0.001) and was related to overall survival (OS) (p < 0.001) and post-progression survival (PPS) (both p = 0.049) in LUAD. Aberrant β-catenin protein expression was higher in male and lung squamous cell carcinoma (LUSC) patients (both p = 0.001). Also, it was considered to be a prognosis factor independently (p = 0.034). In addition, β-catenin protein was negatively correlated with CD8⁺T cells (r = -0.128, p = 0.008), neutrophils (r = -0.198, p < 0.001), immune score (r = -0.109, p = 0.024), stromal score (r = -0.097, p = 0.045), and ESTIMATE score (r = -0.113, p = 0.020). Conclusions: Aberrant β-catenin protein expression was evidently higher in NSCLC and might serve as a biomarker for poor prognosis. Most importantly, β-catenin protein might play an important part in tumor immunity and the tumor microenvironment by inhibiting the infiltration of CD8+ T cells and neutrophils.

Case Report: Targeted Therapy for Metastatic Solid Pseudopapillary Neoplasm of the Pancreas With CTNNB1 and PTEN Mutations

Background

Solid pseudopapillary neoplasm (SPN) of the pancreas shows an indolent clinical behavior in cases undergoing surgical resection. The efficacy of combination therapy in the metastatic extrapancreatic SPN treatment remains largely unknown and a clinical challenge.

Case Presentation

We report a case of a metastatic pancreatic SPN in a 45-year-old woman who presented with an aggressive peritoneal dissemination and hepatic metastases and still showed an indolent clinical course with combination therapy with repeated surgery and targeted therapy. Although the follow-up effect remains to be seen, this is the first report of practical experience of the targeted agents sunitinib and everolimus in metastatic SPN tumors based on the mutation status of PTEN (c.379G>A; p.G127R) and CTNNB1 (c.98C>G; p.S33C). To our knowledge, the PTEN variant identified in this case has not been previously reported in SPN.

Conclusion

Evidence on variant genetics indicates that future molecular studies may not only help to explain the mechanism of SPN occurrence and development but are also more likely to direct to future precision treatments.

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.

Involvement and Targeted Intervention of Mortalin-Regulated Proteome Phosphorylated-Modification in Hepatocellular Carcinoma

OBJECTIVES

To reveal the mechanisms of the effects of mortalin in hepatocellular carcinoma (HCC) and to identify potential novel chemical inhibitors of mortalin.

MATERIALS AND METHODS

For the experiments, three HCC cell lines (HepG2 cells, Hep3B cells, and sorafenib-resistant HuH7 cells) and xenografted nude mice were used. For the clinical analysis, cohorts of 126 patients with HCC and 34 patients with advanced recurrent HCC receiving sorafenib therapy were examined.

RESULTS

Mortalin regulated the phosphorylation-modification of cancer-associated proteins and also regulated angiogenesis-related secretome to cause angiogenesis and sorafenib resistance in HCC cells. Two molecular mechanisms were identified. In one, via phosphatidylinositol 3-kinase (PI3K)/Akt signaling, mortalin regulated nuclear factor (NF)-κB and then activated vascular endothelial growth factor (VEGF)/vascular endothelial growth factor receptor (VEGFR)2 and granulocyte-macrophage colony-stimulating factor (GM-CSF), leading to neovascularization. In the other, mortalin regulated PI3K/Akt/β-catenin and then regulated Bcl-XL and Bcl-2, leading to the antiapoptosis effect of HCC. Treatment of the sorafenib-resistant xenografts with sorafenib in combination with mortalin knockdown facilitated the sorafenib-mediated inhibition of tumor growth and angiogenesis and increased apoptosis. Mortalin was a potential risk factor for HCC, predicting poor prognosis and sorafenib resistance. Finally, we showed that caffeic acid (C9H8O4) could bind to and induce the ubiquitination-mediated degradation of mortalin, which in turn blocked the abovementioned signaling pathways, leading to the inhibition of angiogenesis and the reversal of sorafenib resistance.

CONCLUSIONS

Mortalin, which regulates the phosphorylation of cancer-associated proteins, caused angiogenesis and sorafenib resistance, and was a competitive risk factor for HCC. Caffeic acid can therefore be considered a novel chemical inhibitor that targets the action of mortalin and a potential treatment for HCC.

Risk factors related to postoperative recurrence of dermatofibrosarcoma protuberans: A retrospective study and literature review

BACKGROUND

Dermatofibrosarcoma protuberans (DFSP) is a rare low-grade malignant soft tissue tumor characterized by rosette-like infiltrative growth. Postoperative recurrence of this tumor is very common.

AIM

To evaluate the risk factors related to recurrence after wide local excision (WLE) of DFSP and to guide clinical diagnosis and treatment.

METHODS

The medical records of 44 DFSP patients confirmed by pathology at our hospital from 2012 to 2019 were retrospectively reviewed. The relationship between clinical features, tumor characteristics, treatment, and recurrence risk were analyzed, and the possible risk factors for postoperative tumor recurrence were evaluated.

RESULTS

There were 44 patients in total, including 21 males and 23 females. The median progression free survival was 36 mo (range, 1-240 mo). Twenty patients were treated for the first time, while 24 had previous treatment experience. Forty-two cases were followed for 25.76 ± 22.0 mo, among whom four (9.52%) experienced recurrence after WLE (rate was 9.52%). The recurrence rate in the recurrent group was higher than that in the patients with primary tumor (19.05% vs 0%, P = 0.028). Eighteen cases had a history of misdiagnosis (rate was 40.91%). The recurrence rate among patients with previous experience of misdiagnosis was significantly higher than in patients without (68% vs 36.84%, P = 0.04). The tumor diameter in patients with a history of treatment was larger than in patients treated for the first time (4.75 ± 0.70 cm vs 2.25 ± 0.36 cm, P = 0.004).

CONCLUSION

To sum up, the clinical manifestations of DFSP are not specific and are easily misdiagnosed, thus commonly causing the recurrence of DFSP. After incomplete resection, the tumor may rapidly grow. Previous recurrence history may be a risk factor for postoperative recurrence, and tumor location may have an indirect effect on postoperative recurrence; however, we found no significant correlation between sex, age, course of the disease, or tumor size and postoperative recurrence.

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.

Discovery of chemical probes that suppress Wnt/β-catenin signaling through high-throughput screening

Aberrant activation of the Wnt/β‐catenin signaling pathway has been observed in a wide range of human tumors. Deregulation of the pathway is closely linked to various aspects of human carcinogenesis such as cell viability, regulation of cell cycle, epithelial‐mesenchymal transition, and maintenance of stemness. In addition, recent studies have disclosed the involvement of Wnt signaling in immune evasion of tumor cells. The accumulation of β‐catenin in the nucleus is a common feature of cancer cells carrying defects in the pathway, which leads to the continuous activation of T‐cell factor (TCF)/LEF transcription factors. Consequently, a genetic program is switched on, leading to the uncontrolled growth, prolonged survival, and acquisition of mesenchymal phenotype. As β‐catenin/TCF serves as a signaling hub for the pathway, β‐catenin/TCF‐dependent transcriptional activity is a relevant readout of the pathway. To date, a wide variety of synthetic TCF/LEF reporters has been developed, and high‐throughput screening (HTS) using these reporters has made significant contributions to the discovery of Wnt inhibitors. Indeed, HTS led to the identification of chemical probes targeting porcupine, a membrane bound O‐acyltransferase, and CREB‐binding protein, a transcriptional coactivator. This review focuses on various screening strategies for the discovery of Wnt inhibitors and their mode of action to help the creation of new concepts for assay/screening methods.