Wnt signaling pathway pharmacogenetics in non-small cell lung cancer. Pharmacogenomics J. 2014;14:509-522. [PMID: 24980784 PMCID: PMC4237616 DOI: 10.1038/tpj.2014.21]

Long noncoding RNA H19: functions and mechanisms in regulating programmed cell death in cancer

Long noncoding RNAs (lncRNAs) are a group of noncoding RNAs with transcript lengths of >200 nucleotides. Mounting evidence suggests that lncRNAs are closely associated with tumorigenesis. LncRNA H19 (H19) was the first lncRNA to function as an oncogene in many malignant tumors. Apart from the established role of H19 in promoting cell growth, proliferation, invasion, migration, epithelial-mesenchymal transition (EMT), and metastasis, it has been recently discovered that H19 also inhibits programmed cell death (PCD) of cancer cells. In this review, we summarize the mechanisms by which H19 regulates PCD in cancer cells through various signaling pathways, molecular mechanisms, and epigenetic modifications. H19 regulates PCD through the Wnt/β-catenin pathway and the PI3K-Akt-mTOR pathway. It also acts as a competitive endogenous RNA (ceRNA) in PCD regulation. The interaction between H19 and RNA-binding proteins (RBP) regulates apoptosis in cancer. Moreover, epigenetic modifications, including DNA and RNA methylation and histone modifications, are also involved in H19-associated PCD regulation. In conclusion, we summarize the role of H19 signaling via PCD in cancer chemoresistance, highlighting the promising research significance of H19 as a therapeutic target. We hope that our study will contribute to a broader understanding of H19 in cancer development and treatment.

Unraveling the prevalence of various signalling pathways in non-small-cell lung cancer: a review

Cancer has become a huge public health issue all around the world. The focus of research is on innovative cancer therapy techniques that include the disease's unique targets. Among the cancer-related deaths that occur, lung cancer is considered to be one of the major, accounting for about 1.6 million fatalities globally in 2012, or nearly 20% of all cancer deaths. Non-small-cell lung cancer, a type of lung cancer comprises upto 84% of lung cancer cases, demonstrating the need for a more effective treatment. A novel category of cancer management, known as targeted cancer medicines, has risen to prominence in recent years. Targeted cancer treatments, like traditional chemotherapy, employ pharmacological drugs to slow cancer development, enhance cell death, and prevent it from spreading. Targeted treatments, as the name implies, work by interfering with particular proteins implicated in cancer. Numerous research conducted in the last several decades have led to the conclusion that signalling pathways are involved in the growth of lung cancer. All malignant tumours are produced, spread, invade, and behave in various abnormal ways due to abnormal pathways. Numerous significant signalling pathways, including the RTK/RAS/MAP-Kinase pathway (hence often referred to as RTK-RAS for simplicity), PI3K/Akt signalling, and others, have been discovered as commonly genetically changed. The current developments in research on various signalling pathways, as well as the underlying mechanisms of the molecules implicated in these pathways, are innovatively summarised in this review. To give a good sense of the study that has been done so far, many routes are placed together. Thus, this review includes the detailed description regarding each pathways, the mutations formed, and the present treatment strategy to overcome the resistance.

CBX4 deletion promotes tumorigenesis under KrasG12D background by inducing genomic instability

Chromobox protein homolog 4 (CBX4) is a component of the Polycomb group (PcG) multiprotein Polycomb repressive complexes 1 (PRC1), which is participated in several processes including growth, senescence, immunity, and tissue repair. CBX4 has been shown to have diverse, even opposite functions in different types of tissue and malignancy in previous studies. In this study, we found that CBX4 deletion promoted lung adenocarcinoma (LUAD) proliferation and progression in KrasG12D mutated background. In vitro, over 50% Cbx4L/L, KrasG12D mouse embryonic fibroblasts (MEFs) underwent apoptosis in the initial period after Adeno-Cre virus treatment, while a small portion of survival cells got increased proliferation and transformation abilities, which we called selected Cbx4-/-, KrasG12D cells. Karyotype analysis and RNA-seq data revealed chromosome instability and genome changes in selected Cbx4-/-, KrasG12D cells compared with KrasG12D cells. Further study showed that P15, P16 and other apoptosis-related genes were upregulated in the primary Cbx4-/-, KrasG12D cells due to chromosome instability, which led to the large population of cell apoptosis. In addition, multiple pathways including Hippo pathway and basal cell cancer-related signatures were altered in selected Cbx4-/-, KrasG12D cells, ultimately leading to cancer. We also found that low expression of CBX4 in LUAD was associated with poorer prognosis under Kras mutation background from the human clinical data. To sum up, CBX4 deletion causes genomic instability to induce tumorigenesis under KrasG12D background. Our study demonstrates that CBX4 plays an emerging role in tumorigenesis, which is of great importance in guiding the clinical treatment of lung adenocarcinoma.

METTL3 promotes the malignancy of non-small cell lung cancer by N6-methyladenosine modifying SFRP2

This study aimed to investigate the roles of METTL3, a regulator of m6A, in NSCLC. RT-qPCR was applied to determine mRNA of m6A-associated genes and SFRP2, and western blot were used for ZEB1 and MMP9 protein expression. Total m6A level was measured using methylated RNA immunoprecipitation (MeRIP) assay, and RIP was used to access m6A level of SFRP2. Cellular behaviors were detected using CCK-8 and tranwell assays. Xenograft assays were conducted to further verify the roles of METTL3 and SFRP2 in NSCLC. The expression level of METTL3 was higher in NSCLC than normal controls. However, downregulation of METTL3 restrained the proliferation, migration and invasion of NSCLC cells. Enhanced expression of METTL3 caused the inverse consequences. Moreover, SFRP2 was found to be negatively regulated by METTL3. Intriguingly, the anti-tumor functions of METTL3 knockdown in the phenotype of NSCLC cells and xenograft mice were overturned by inhibition of SFRP2. Silencing METTL3 resulted in the enhanced stability of SFRP2. Finally, downregulation of SFRP2 induced by METTL3 activated the Wnt/β-catenin signaling pathway in NSCLC. METTL3 acted as an oncogene in the pathogenesis of NSCLC via suppressing SFRP2 to activate Wnt/β-catenin signaling pathway, indicating that METTL3 might be a promising predictor in NSCLC.

Preksha Dhyāna Meditation Effect on the DNA Methylation Signature in College Students

Introduction: The stress and psychological factors affect the human transcriptomic and epigenomic landscapes. Preksha Dhyana meditation (PM) was found to be effective, in novice healthy college student meditators, at the cognitive skills and transcriptomic levels. Recently published data showed that PM induced alterations at the transcriptome level in healthy and novice college students. Methods: To decipher potential mechanisms underlying the PM effect at the cellular level, array-based methylation analyses in peripheral blood were performed at baseline and 8 weeks postintervention in 34 participants. Results: Overall, 470 CpG sites were nominally differentially methylated (p ≤ 0.05 and change magnitude from ≥3% to ≤ -3%) between baseline and 8 weeks postintervention with 180 sites hypermethylated and 290 sites hypomethylated. Pathway analysis of the genes linked to the differentially methylated sites revealed the enrichment of several molecular and cellular signaling pathways, especially metabolic and brain function signaling pathways. Conclusions: Besides its beneficial effects on cognitive skills and transcriptome alterations, the current data indicate that PM meditation also affects the DNA methylation profile of novice and healthy college students 8 weeks postintervention. Clinical Trial Registration number: NCT03779269.

Biogenesis, functions, and clinical implications of circular RNAs in non-small cell lung cancer

Lung cancer (LC) is the leading cause of cancer-related deaths worldwide, with high morbidity and mortality. Non-small cell lung cancer (NSCLC) is a major pathological type of LC and accounts for more than 80% of all cases. Circular RNAs (circRNAs) are a large class of non-coding RNAs (ncRNAs) with covalently closed-loop structures, a high abundance, and tissue-specific expression patterns. They participate in various pathophysiological processes by regulating complex gene networks involved in proliferation, apoptosis, migration, and epithelial-to-mesenchymal transition (EMT), as well as metastasis. A growing number of studies have revealed that the dysregulation of circRNAs contributes to many aspects of cancer progression, such as its occurrence, metastasis, and recurrence, suggesting their great potential as efficient and specific biomarkers in the diagnosis, prognosis, and therapeutic targeting of NSCLC. In this review, we systematically elucidate the characteristics, biogenesis, and functions of circRNAs and focus on their molecular mechanisms in NSCLC progression. Moreover, we highlight their clinical implications in NSCLC treatment.

Identification of Novel Lung Cancer Driver Genes Connecting Different Omics Levels With a Heat Diffusion Algorithm

Cancer driver gene is a type of gene with abnormal alterations that initiate or promote tumorigenesis. Driver genes can be used to reveal the fundamental pathological mechanisms of tumorigenesis. These genes may have pathological changes at different omics levels. Thus, identifying cancer driver genes involving two or more omics levels is essential. In this study, a computational investigation was conducted on lung cancer driver genes. Four omics levels, namely, epigenomics, genomics, transcriptomics, and post-transcriptomics, were involved. From the driver genes at each level, the Laplacian heat diffusion algorithm was executed on a protein–protein interaction network for discovering latent driver genes at this level. A following screen procedure was performed to extract essential driver genes, which contained three tests: permutation, association, and function tests, which can exclude false-positive genes and screen essential ones. Finally, the intersection operation was performed to obtain novel driver genes involving two omic levels. The analyses on obtained genes indicated that they were associated with fundamental pathological mechanisms of lung cancer at two corresponding omics levels.

Dextran sulfate inhibits cell proliferation and induces apoptosis by regulating EZH2 in gastric carcinoma

BACKGROUND

Gastric cancer (GC) is one of the most common gastrointestinal malignancies. According to reports, the enhancer of zeste homolog 2 (EZH2) exhibits carcinogenic function in a variety of cancers. Therefore, EZH2 may be a potential therapeutic target for the treatment of human cancer. Macromolecular dextran sulfate (DS) has been displayed to play a critical role in tumor inhibition. However, the molecular mechanism by which DS mediates this effect is unclear.

OBJECTIVES

In this study, we explored the effects of DS on the proliferation and apoptosis of gastric cancer and the related mechanisms. Cell proliferation and counting assays, as well as cell colony formation assays, revealed that DS inhibited the proliferation and tumorigenesis of GC cells. Additionally, flow cytometry analysis displayed that DS blocked the cell cycle of GC cells in the G1/S phase and promoted their apoptosis.

METHODS

Bioinformatics analyses, enzyme-linked immunosorbent assays, immunohistochemistry, and other methods were applied to measure the expression of EZH2 in human GC cells and tissues.

RESULTS AND DISCUSSION

Further studies have shown that DS treatment can reduce the expression of proliferating cell nuclear antigen (PCNA) and increase the level of the ratio of Bax: Bcl-2 protein in GC cells. In addition, DS reduced EZH2 levels and increased CXXC finger protein 4 levels both in vitro and in vivo. In addition, down-regulation of EZH2 with EZH2 inhibitors reversed the inhibitory effect of DS on gastric cancer cells.

CONCLUSION

Collectively, our work demonstrates that DS suppresses proliferation and promotes apoptosis of GC cells by regulating EZH2. Our study suggests that DS is a promising therapeutic compound for the treatment of GC.

Apatinib suppresses lung cancer stem-like cells by complex interplay between β-catenin signaling and mitochondrial ROS accumulation

The abnormal activation of Wnt/β-catenin signaling plays a critical role in the development of lung cancer, which is also important in the generation and maintenance of lung cancer stem cell (CSC). CSCs have unique capabilities to resist anticancer therapy, seed recurrent tumors, and disseminate to and colonize distant tissues. Apatinib, a small-molecule VEGFR2-tyrosine kinase inhibitor, shows highly efficient antitumor activity in heavily treated, chemoresistant, and metastatic lung cancer. We speculated that inhibition of Wnt/β-catenin signaling and targeting lung CSCs could be one of the anti-tumor mechanisms of apatinib. In the present study we demonstrated that apatinib repressed lung CSC-like traits by hindering sphere formation ability, lung CSC-related marker expression and decreasing chemoresistance derived stemness. Mechanistically, apatinib exerted its anti-CSC effects by inhibiting β-catenin and its downstream targets. Moreover, apatinib induced the production of reactive oxyen species (ROS), which participated in the inhibitory effects of apatinib on lung CSCs. It was found that β-catenin regulated apatinib-induced production of ROS. Inhibition or promotion of ROS production with N-acetyl-L-cysteine or H₂O₂ not only upregulated or downregulated β-catenin expression, but also prevented or promoted DNA damage, rescued or impeded sphere formation, respectively. Collectively, our findings reveal that apatinib directly inhibits β-catenin signaling and promotes ROS generation to suppress lung CSC-like characteristics. A clearer understanding of the anti-cancer mechanisms of apatinib is required for its better application in combating advanced and refractory/recurrent lung cancer when combined with conventional chemotherapy.

WNT5B in Physiology and Disease

WNT5B, a member of the WNT family of proteins that is closely related to WNT5A, is required for cell migration, cell proliferation, or cell differentiation in many cell types. WNT5B signals through the non-canonical β-catenin-independent signaling pathway and often functions as an antagonist of canonical WNT signaling. Although WNT5B has a high amino acid identity with WNT5A and is often assumed to have similar activities, WNT5B often exhibits unique expression patterns and functions. Here, we describe the distinct effects and mechanisms of WNT5B on development, bone, adipose tissue, cardiac tissue, the nervous system, the mammary gland, the lung and hematopoietic cells, compared to WNT5A. We also highlight aberrances in non-canonical WNT5B signaling contributing to diseases such as osteoarthritis, osteoporosis, obesity, type 2 diabetes mellitus, neuropathology, and chronic diseases associated with aging, as well as various cancers.

MiR-129-5p promotes radio-sensitivity of NSCLC cells by targeting SOX4 and RUNX1

BACKGROUND

Dysregulation of microRNAs (miRNAs) figures prominently in radio-sensitivity of non-small cell lung cancer (NSCLC). MiR-129-5p can block the development of a variety of tumors. However, whether miR-129-5p modulates radio-sensitivity of NSCLC cells remains unknown.

OBJECTIVE

This study was aimed to explore the role and the underlying mechanism of miR-129-5p in the radiosensitivity of NSCLC.

METHODS

Radio-resistant NSCLC cell lines (A549-R and H1299-R) were constructed using A549 and H1299 cells. Quantitative real-time polymerase chain reaction (qRT-PCR) was employed to quantify miR-129-5p, SRY-box transcription factor 4 (SOX4) mRNA, and RUNX family transcription factor 1 (RUNX1) mRNA expression levels. Cell apoptosis and cell cycle were detected by flow cytometry. Cell counting kit-8 (CCK-8) assay and colony formation experiments were used to measure cell proliferation. γ-H2AX was examined by Western blot to confirm DNA injury. Dual-luciferase reporter experiments were applied to analyze the interactions among miR-129-5p, RUNX1, and SOX4.

RESULTS

In A549-R and H1299-R cells, compared with the wild type cell lines, miR-129-5p expression was remarkably reduced while SOX4 and RUNX1 expressions were increased. The transfection of miR-129-5p into NSCLC cell lines, markedly induced cell apoptosis, DNA injury, and cell cycle arrest, and inhibited cell proliferation and colony formation. RUNX1 and SOX4 were validated as target genes of miR-129-5p, and the restoration of RUNX1 or SOX4 could counteract the influence of miR-129-5p on A549-R cells.

CONCLUSION

MiR-129-5p sensitizes A549-R and H1299-R cells to radiation by targeting RUNX1 and SOX4.

Cu/Zn Superoxide Dismutase (Sod1) regulates the canonical Wnt signaling pathway

Cu/Zn Superoxide Dismutase (Sod1) catalyzes the disproportionation of cytotoxic superoxide radicals (O2•-) into oxygen (O2) and hydrogen peroxide (H2O2), a key signaling molecule. In Saccharomyces cerevisiae, we previously discovered that Sod1 participates in an H2O2-mediated redox signaling circuit that links nutrient availability to the control of energy metabolism. In response to glucose and O2, Sod1-derived H2O2 stabilizes a pair of conserved plasma membrane kinases - yeast casein kinase 1 and 2 (Yck1/2) - that signal glycolytic growth and the repression of respiration. The Yck1/2 homolog in humans, casein kinase 1-γ (CK1γ), is an integral component of the Wingless and Int-1 (Wnt) signaling pathway, which is essential for regulating cell fate and proliferation in early development and adult tissue and is dysregulated in many cancers. Herein, we establish the conservation of the SOD1/YCK1 redox signaling axis in humans by finding that SOD1 regulates CK1γ expression in human embryonic kidney 293 (HEK293) cells and is required for canonical Wnt signaling and Wnt-dependent cell proliferation.

Norcantharidin: research advances in pharmaceutical activities and derivatives in recent years

Cantharidin (CTD) is the main bioactive component of Cantharides, which is called Banmao in Traditional Chinese Medicine (TCM). Norcantharidin (NCTD) is a structural modifier of CTD. To compare with CTD, NCTD has lighter side effects and stronger bioactivity in anti-cancer through inhibiting cell proliferation, causing apoptosis and autophagy, overwhelming migration and metastasis, affecting immunity as well as lymphangiogenesis. Examples of these effects include suppressing Protein Phosphatase 2A and modulating Wnt/beta catenin signal, with Caspase family proteins, AMPK pathway and c-Met/EGFR pathway involving respectively. Moreover, NCTD has the effects of immune enhancement, anti-platelet aggregation and inhibition of renal interstitial fibrosis with distinct signaling pathways. The immunological effects induced by NCTD are related to the regulation of macrophage polarization and LPS-mediated immune response. The antiplatelet activity that NCTD induced is relevant to the inhibition of platelet signaling and the downregulation of α2 integrin. Furthermore, some of novel derivatives designed and synthesized artificially show stronger biological activities (e.g., anticancer effect, enzyme inhibition effect, antioxidant effect) and lower toxicity than NCTD itself. Plenty of literatures have reported various pharmacological effects of NCTD, particularly the anticancer effect, which has been widely concerned in clinical application and laboratory research. In this review, the pharmaceutical activities and derivatives of NCTD are discussed, which can be reference for further study.

Glycogen synthase kinase-3β: a promising candidate in the fight against fibrosis

Fibrosis exists in almost all organs/tissues of the human body, plays an important role in the occurrence and development of diseases and is also a hallmark of the aging process. However, there is no effective prevention or therapeutic method for fibrogenesis. As a serine/threonine (Ser/Thr)-protein kinase, glycogen synthase kinase-3β (GSK-3β) is a vital signaling mediator that participates in a variety of biological events and can inhibit extracellular matrix (ECM) accumulation and the epithelial-mesenchymal transition (EMT) process, thereby exerting its protective role against the fibrosis of various organs/tissues, including the heart, lung, liver, and kidney. Moreover, we further present the upstream regulators and downstream effectors of the GSK-3β pathway during fibrosis and comprehensively summarize the roles of GSK-3β in the regulation of fibrosis and provide several potential targets for research. Collectively, the information reviewed here highlights recent advances vital for experimental research and clinical development, illuminating the possibility of GSK-3β as a novel therapeutic target for the management of tissue fibrosis in the future.

miR-1269b Drives Cisplatin Resistance of Human Non-Small Cell Lung Cancer via Modulating the PTEN/PI3K/AKT Signaling Pathway

Background

MiRNAs have been reported to induce certain drug resistance in multiple solid tumors via various mechanisms. Our study aimed to investigate whether miRNA-1269b was involved in the chemoresistance and the progression of non-small cell lung cancer (NSCLC).

Methods

MTT and colony formation assay were conducted to determine cell proliferation and cell apoptosis was analyzed by flow cytometry with annexin V/PI. Luciferase reporter assay was performed to validate miRNA-targeting sequences. The function of miR-1269b in cisplatin-resistant was evaluated in vivo in a mouse tumor model.

Results

We found that miR-1269b expression was up-regulated in cisplatin-resistant NSCLC specimens and NSCLC cell lines, which resulted in the promotion of chemoresistance and tumorigenicity. miR-1269b overexpression enhanced drug resistance and promoted cell proliferation in vitro and tumor growth in vivo, with reduced apoptosis rate of A549 cells inin vitro cell culture. Mechanistically, we identified PTEN as the direct target of miR-1269b, and the PTEN level was negatively correlated with miR-1269b in NSCLC specimens. Further study demonstrated that miR-1269b targeted PTEN to modulate PI3K/AKT signaling pathway.

Conclusion

In conclusion, these findings suggest that the miR-1269b/PTEN/PI3K/AKT-mediated network might promote cisplatin resistance in NSCLC, and that miR-1269b can be a potential therapeutic target for chemoresistance in NSCLC patients.

Wnt Signaling: Paths for Cancer Progression

The Wnt signaling pathways are well known for having several pivotal roles during embryonic development. However, the same developmental signaling pathways also present key roles in cancer initiation and progression. In this chapter, several issues regarding the roles of both canonical and non-canonical Wnt signaling pathways in cancer will be explored, mainly concerning their role in the maintenance of cancer stemness, in the metabolism reprograming of cancer cells and in the modulation of the tumor microenvironment. The role of Wnt signaling cascades in the response of cancer cells to anti-cancer treatments will be also discussed, as well as its potential therapeutic targeting during cancer treatment. Collectively, increasing evidence has been supporting pivotal roles of Wnt signaling in several features of cancer biology, however; a lot is still to be elucidated.

Wnt3a protein overexpression predicts worse overall survival in laryngeal squamous cell carcinoma

As a classical ligand in the canonical Wnt/β-catenin signaling pathway, the role of Wnt3a in laryngeal squamous cell carcinoma (LSCC) remains unclear. Therefore, the expression pattern of the Wnt3a protein in 222 primary LSCC, and 19 corresponding adjacent non-carcinoma specimens, was detected by immunohistochemistry and further correlated with clinicopathological parameters. The results showed that LSCC tissue expressed higher levels of the Wnt3a protein when compared to the corresponding adjacent non-cancerous tissues. High expression of Wnt3a was closely related to histological grade (P = 0.031), clinical stage (I+II / III+IV; P = 0.004), and lymph node metastasis (P = 0.03). Kaplan-Meier analysis evidenced that a worse overall survival (OS) was correlated to the group with high Wnt3a expression (P = 0.003). When stratified survival analyses were performed, patients with lymph node metastasis/advanced clinical stages and high Wnt3a expression had worse OS rates than patients with other features (P < 0.001). Finally, multivariate analysis showed that Wnt3a expression was an independent prognosis factor for LSCC patients. The current findings suggest that Wnt3a is tightly related to the LSCC progression and could serve as a valuable clinic biomarker for LSCC patients.

MiR-216a-5p targets TCTN1 to inhibit cell proliferation and induce apoptosis in esophageal squamous cell carcinoma

Background

MiR-216a-5p has been reported to be associated with several tumors, including prostate cancer and melanoma. However, its expression level and potential role in esophageal squamous cell carcinoma (ESCC) remain uncertain.

Results

Here, we found that miR-216a-5p expression was significantly down-regulated in clinical ESCC tissues and cells. Functional assays were performed to evaluate the biological effects of miR-216a-5p on cell proliferation and cell apoptosis by CCK-8 assay and flow cytometry in ESCC cell lines, EC9706 and TE-9. The results showed that miR-216a-5p overexpression repressed cell proliferation and induced cell apoptosis. Through bioinformatics prediction and luciferase reporter assay, we revealed that miR-216a-5p could directly target tectonic family member 1 (TCTN1). Moreover, TCTN1 was obviously suppressed by miR-216a-5p overexpression. In addition, TCTN1 expression was significantly increased and inversely correlated with the levels of miR-216a-5p in ESCC tissues. More importantly, down-regulation of TCTN1 imitated, while restoration of TCTN reversed the effects of miR-216a-5p on cell proliferation and apoptosis. At the molecular level, we further found that TCTN1 overexpression reversed the effects of miR-216a-5p transfection on the expression of PCNA, Bcl-2 and Bad.

Conclusions

Our results demonstrate that miR-216a-5p might serve as a tumor suppressor in ESCC cells through negatively regulating TCTN1 expression, indicating the possibility that miR-216a-5p and TCTN1 might be attractive targets for ESCC therapeutic intervention.

Long non-coding RNA NORAD promotes the occurrence and development of non-small cell lung cancer by adsorbing MiR-656-3p

Background

To explore the role of non‐coding RNA activated by DNA damage (NORAD), a long non‐coding ribonucleic acid (lncRNA), in non‐small cell lung cancer (NSCLC) and its possible mechanism.

Methods

Quantitative real‐time polymerase chain reaction was adopted for the detection of the expression levels of NORAD, micro RNA (miR)‐656‐3p, and AKT serine/threonine kinase 1 (AKT1). The effects of NORAD, miR‐656‐3p, and AKT1 on cell proliferation and migration were examined through the Cell Counting Kit‐8 (CCK‐8) and Transwell assay. Subsequently, the binding relationships between miR‐656‐3p and AKT1 and between miR‐656‐3p and NORAD were verified by dual‐luciferase reporter gene assay. Finally, the potential mechanisms of action of NORAD and miR‐656‐3p were explored through the torsion experiment.

Results

The lncRNA NORAD expression level in NSCLC patients was notably higher than that in people in control group, that in patients with metastasis was higher than that in patients without metastasis, and that in patients with NSCLC in stage III‐IV was significantly higher than that in patients with NSCLC in stage I‐II. Elevation of NORAD stimulated the proliferation and migration of NSCLC A549/H460 cells. According to the reporter gene assay, NORAD could bind to miR‐656‐3p. Besides, miR‐656‐3p was significantly under‐expressed in cancer tissues of patients with NSCLC, and overexpression of miR‐656‐3p could block the proliferation and migration of A549/H460 cells and reversed promotion on cell proliferation and migration by NORAD. Furthermore, the reporter gene assay revealed that the overexpression of AKT1, a miR‐656‐3p target gene, could reverse miR‐656‐3p's inhibitory effect on the proliferation and migration of A549/H460 cells.

Conclusion

LncRNA NORAD is capable of promoting the proliferation and migration of NSCLC cells, and its mechanism may be that it increases the AKT1 expression by adsorbing miR‐656‐3p.

miR-552-5p facilitates osteosarcoma cell proliferation and metastasis by targeting WIF1

miR-552 promotes tumor growth and metastasis in colorectal cancer. However, the function of miR-552 in osteosarcoma remains unclear. The current study investigated the role and mechanism of miR-552-5p in the proliferation, migration and invasion of osteosarcoma cells. miR-552-5p was significantly upregulated in osteosarcoma tissues and cell lines compared with adjacent normal tissues and normal osteoblast cells. Knockdown of miR-552-5p significantly reduced the proliferation of MG63 and U2OS cells, and inhibited cell migration and invasion. Wnt inhibitory factor 1 (WIF1) was the direct target gene of miR-552-5p in osteosarcoma cells. Overexpression of miR-552-5p markedly decreased the expression of WIF1 in MG63 and U2OS cells. A negative association was identified between the expression levels of miR-552-5p and WIF1 in osteosarcoma tissues. Furthermore, the expression of WIF1 was downregulated in osteosarcoma tissues and cell lines. Finally, knockdown of WIF1 in MG63 and U2OS cells treated with miR-552-5p inhibitors rescued their ability to proliferate, migrate and invade. Overall, the results indicated that miR-552-5p promoted osteosarcoma development and progression by inhibiting WIF1. Therefore, miR-552-5p may serve as a new therapeutic target for treatment of patients with osteosarcoma.

Diagnostic role of Wnt pathway gene promoter methylation in non small cell lung cancer

Wnt signal pathway genes are known to be involved with cancer development. Here we tested the hypothesis whether DNA methylation of genes part of the Wnt signaling pathway could help the diagnosis of non-small cell lung cancer (NSCLC). The methylation levels of SFRP1, SFRP2, WIF1 and PRKCB in 111 NSCLC patients were evaluated by quantitative methylation-specific PCR (qMSP). Promoter methylation levels of four candidate genes were significantly higher in tumor tissues compared with the adjacent tissues. SFRP1, SFRP2 and PRKCB genes were all shown to be good predictors of NSCLC risk (SFRP1: AUC = 0.711; SFRP2: AUC = 0.631; PRKCB: AUC = 0.650). The combined analysis showed that the methylation status of the four genes had a sensitivity of 70.3% and a specificity of 73.9% in the prediction of NSCLC risk for study cohort. A higher diagnostic value with an AUC of 0.945 (95% CI: 0.923–0.967, sensitivity: 90.6%, specificity: 93.0%) was found in TCGA cohort. In addition, SFRP1 and SFRP2 hypermethylation events were specific to male patients. Further TCGA data mining analysis suggested that SFRP1_cg15839448, SFRP2_cg05774801, and WIF1_cg21383810 were inversely associated with the host gene expression. Moreover, GEO database analysis showed that 5′-Aza-deoxycytidine was able to upregulate gene expression in several lung cancer cell lines. Subsequent dual-luciferase reporter assay showed a crucial regulatory function of PRKCB promoter. In summary, our study showed that a panel of Wnt signal pathway genes (SFRP1, SFRP2, WIF1 and PRKCB) had the potential as methylation biomarkers in the diagnosis of NSCLC.

Artemisinin and its derivatives can significantly inhibit lung tumorigenesis and tumor metastasis through Wnt/β-catenin signaling

Non-small-cell lung cancer (NSCLC) is the most prevalent malignancy worldwide given its high incidence, considerable mortality, and poor prognosis. The anti-malaria compounds artemisinin (ART), dihydroartemisinin (DHA), and artesunate (ARTS) reportedly have anti-cancer potential, although the underlying mechanisms remain unclear. In this work, we used flow cytometry to show that ART, DHA, and ARTS could inhibit the proliferation of A549 and H1299 cells by arresting cell cycle in G1 phase. Meanwhile, tumor malignancy including migration, invasion, cancer stem cells, and epithelial-mesenchymal transition were also significantly suppressed by these compounds. Furthermore, ART, DHA, and ARTS remarkably decreased tumor growth in vivo. By using IWP-2, the inhibitor of Wnt/β-catenin pathway, and Wnt5a siRNA, we found that ART, DHA, and ARTS could render tumor inhibition partially dependent on Wnt/β-catenin inactivation. These compounds could strikingly decrease the protein level of Wnt5-a/b and simultaneously increase those of NKD2 and Axin2, ultimately resulting in β-catenin downregulation. In summary, our findings revealed that ART, DHA, and ARTS could suppress lung-tumor progression by inhibiting Wnt/β-catenin pathway, thereby suggesting a novel target for ART, DHA, and ARTS in cancer treatment.

CXXC4 activates apoptosis through up-regulating GDF15 in gastric cancer

Worldwide, gastric cancer is one of the most fatal cancers. Epigenetic alterations in gastric cancer play important roles in silencing of tumor suppressor genes. We previously found that CXXC finger protein 4 (CXXC4) was a novel tumor suppressor in gastric cancer. In this report, we demonstrated that CXXC4 inhibited growth of gastric cancer cells as a pro-apoptotic factor. This inhibition could be reversed by the pan-caspase inhibitor called Z-VAD-FMK. However, CXXC4 with mutations in its DNA binding domain failed to induce apoptosis. Growth differentiation factor 15 (GDF15) was identified as one of potential targets responsible for CXXC4-induced apoptosis. CXXC4 activated GDF15 transcription through enhancing the interaction of transcription factor Sp1 with GDF15 promoter. In summary, the nuclear protein CXXC4 activated apoptosis in gastric cancer through up-regulating its novel potential downstream target GDF15. GDF15 might be a promising target for clinical treatment of gastric cancer with CXXC4 deficiency.

miR-181c contributes to cisplatin resistance in non-small cell lung cancer cells by targeting Wnt inhibition factor 1

PURPOSE

miRNAs are implicated in drug resistance of multiple cancers including non-small cell lung cancer (NSCLC), highlighting the potential of miRNAs as chemoresistance regulators in cancer treatment. This study aims to explore the relationship between miR-181c and chemoresistance of NSCLC cells.

METHODS

qRT-PCR was conducted to examine the expression of miR-181c in NSCLC tissues, and parental and cisplatin (DDP)-resistant NSCLC cells. MTT assay and flow cytometry were performed to detect the survival rate and apoptosis in NSCLC cells. Luciferase reporter assay was performed to confirm the potential target of miR-181c. Xenograft tumor experiment was applied to confirm the effect of miR-181c on DDP sensitivity of DDP-resistant NSCLC cells in vivo.

RESULTS

miR-181c was upregulated in NSCLC tissues, and parental and DDP-resistant NSCLC cells. miR-181c downregulation or WIF1 overexpression increased DDP sensitivity of DDP-resistant NSCLC cells by decreasing survival rate and promoting DDP-induced apoptosis. miR-181c was demonstrated to be able to bind to WIF1 and negatively regulate the expression of WIF1. WIF1 knockdown abolished anti-miR-181c-induced DDP sensitivity. Moreover, anti-miR-181c suppressed the Wnt/β-catenin pathway by regulating WIF1. XAV939 treatment reversed miR-181c-induced increase in IC50 value and miR-181c-triggered decrease in apoptosis. Finally, anti-miR-181c improved DDP sensitivity of DDP-resistant NSCLC cells in vivo.

CONCLUSION

miR-181c contributed to DDP resistance in NSCLC cells through activation of the Wnt/β-catenin pathway by targeting WIF1, providing a potential therapeutic application for the treatment of patients with DDP-resistant NSCLC in the future.

The RNA-binding protein Sam68 is critical for non-small cell lung cancer cell proliferation by regulating Wnt/β-catenin pathway

Src associated in mitosis, 68 kDa (Sam68) is a KH domain RNA-binding protein that regulates a broad scope of biological events, including RNA metabolism, transcription and signal transduction. Herein, we aimed to explore the expression, clinical significance and biological function of Sam68 in human non-small cell lung cancer (NSCLC). By applying quantitative real-time PCR (qRT-PCR), western blotting and immunohistochemistry (IHC) methods, we found that nucleic localized Sam68 was markedly overexpressed in NSCLC tissues and cell lines. By X² analysis and Kaplan-Meier survivial analysis between Sam68 expression and various clinicopathological features, Sam68 was found to be significantly associated with clinical T stage, advanced tumor grade, and short overall survival. Finally, in vitro loss-of-function studies showed that knockdown of Sam68 inhibited cell proliferation, colony formation and cell cycle progression in NSCLC cells. Moreover, our results clarified that knockdown of Sam68 could suppress NSCLC cell proliferation via the inhibition of Wnt/β-catenin pathway. To conclude, our results demonstrated that upregulation of Sam68 in NSCLC resulted in poor prognosis, and it promoted cell proliferation via activating Wnt/β-catenin signaling pathway, which could serve as a novel biomarker for the prognosis and therapy of NSCLC.

DKK1 promotes migration and invasion of non-small cell lung cancer via β-catenin signaling pathway

Disregulation of dickkopf-related protein 1 (DKK1) has been reported in a variety of human cancers. However, how DKK1 functions in Non-small cell lung cancer has not been revealed. In the current study, DKK1 was knocked out by the lentivirus-mediated short hairpin RNA interference approach in H1299 and 95C non-small cell lung cancer cell lines. Subsequently, the migration and invasion ability were assessed by wound-healing and transwell assays. In addition, epithelial-mesenchymal transition markers and β-catenin were examined by Western blot analysis. The signaling pathway downstream of DKK1 was characterized using the Wnt signaling pathway inhibitor, IWP2, and glycogen synthase kinase 3 beta inhibitor, LiCl. Immunofluorescence analysis investigated the subcellular localization of β-catenin. The results suggested that knockdown of DKK1 caused reduced migration and invasion ability of H1299 and 95C cells. DKK1 silencing resulted in the downregulation of epithelial-mesenchymal transition-related proteins, such as Snail and zinc finger E-box binding homeobox 1. Besides, DKK1 silencing inhibited β-catenin and promoted the phosphorylation of β-catenin. Mechanism results indicated that the expression of β-catenin was reduced in H1299 or 95C cells after being treated with Wnt signaling inhibitor, IWP2. In addition, the inhibition of β-catenin phosphorylation by glycogen synthase kinase 3 beta inhibitor, LiCl, significantly enhanced the migration and invasion capacities in DKK1-knockdown cell lines. Furthermore, cell immunofluorescence revealed that nuclear β-catenin was reduced when DKK1 was knocked down. Taken together, these findings suggest that DKK1 induces the occurrence of epithelial-mesenchymal transition and promotes migration and invasion in non-small cell lung cancer cells. Mechanically, β-catenin plays a vital role in DKK1-induced non-small cell lung cancer cell migration and invasion, and DKK1 inhibits the phosphorylation of β-catenin, resulting in the increased nuclear localization of β-catenin.

WITHDRAWN: MicroRNA-505 modulates cancer proliferation and migration in human non-small cell lung cancer through inverse regulation of FZD4

This article has been withdrawn at the request of the Editor-in-Chief. Following peer-review and acceptance of the above referenced paper for publication in Lung Cancer, the Editor-in-Chief was contacted by the Editor-in-Chief of the journal, Gene Therapy, with information that the manuscript had simultaneously been submitted to both Lung Cancer and Gene Therapy. A referee selected to review the manuscript for Gene Therapy was also contacted by the Editor-in-Chief of the journal, Respiratory Research, with a request to review the same manuscript for that journal. The three journals ascertained that the manuscript had been simultaneously submitted to all three journals. In addition, as part of their investigation of potential simultaneous submission, the Editors of Lung Cancer compared the manuscript submitted to Gene Therapy with that accepted for publication in Lung Cancer, and this has raised concerns related to the data presented in the paper. The paper accepted for publication in Lung Cancer examines A549 and H810 cells. The paper submitted to Gene Therapy examines A549 and H510A cells. However, the data presented in both papers, including the figures, are identical. The Editors of Lung Cancer have asked the authors for an explanation, but the corresponding author has not responded. The Publisher apologizes for any inconvenience this may cause. The full Elsevier Policy on Article Withdrawal can be found at https://www.elsevier.com/about/our-business/policies/article-withdrawal.

Loss of Secreted Frizzled-Related Protein-1 expression is associated with poor prognosis in intrahepatic cholangiocarcinoma

AIMS

Secreted Frizzled-Related Protein-1 (SFRP1) is a well-known negative regulator of the wingless type (Wnt)-β-catenin pathway and its inactivation plays an important role in the development and progression of many cancers. In this study, we aimed to determine the clinical significance of SFRP1 expression in intrahepatic cholangiocarcinoma (IHCC) and to define the relationship to Wnt-β-catenin pathway.

METHODS

Fifty IHCC patients who had liver resection were enrolled in this study. SFRP1 protein expression was examined by immunohistochemistry in tumor tissues. The patients were divided into two groups: SFRP1 positive (n = 30) and negative (n = 20). Clinicopathological characteristics were analyzed.

RESULTS

SFRP1 significantly correlated with curability (Cur A, B vs. C, p = 0.029); and recurrent pattern (intrahepatic vs. extrahepatic, p = 0.010). The negative SFRP1 group had significantly poorer prognosis, and 5-year survival rates were 8.1% of the negative SFRP1 group and 44.6% of the positive SFRP1 group, respectively. Moreover, the disease-free survival rate in the negative SFRP1 group was significantly poorer (p < 0.001). Multivariate analysis revealed that loss of SFRP1served as an independent prognostic factor in IHCC for both overall (HR, 2.923; 95% CI, 1.30-6.56; p = 0.009) and disease-free (HR, 2.631; 95% CI, 1.31-5.27; p = 0.006) survival. In addition, SFRP1 expression negatively correlated to β-catenin expression (p = 0.005).

CONCLUSIONS

Those results suggested that the loss of SFRP1 could be a poor prognostic factor for IHCC, through the Wnt-β-catenin pathway.

Gene expression and pathway analysis of CTNNB1 in cancer and stem cells

AIM

To investigate β-catenin (CTNNB1) signaling in cancer and stem cells, the gene expression and pathway were analyzed using bioinformatics.

METHODS

The expression of the catenin β 1 (CTNNB1) gene, which codes for β-catenin, was analyzed in mesenchymal stem cells (MSCs) and gastric cancer (GC) cells. Beta-catenin signaling and the mutation of related proteins were also analyzed using the cBioPortal for Cancer Genomics and HOMology modeling of Complex Structure (HOMCOS) databases.

RESULTS

The expression of the CTNNB1 gene was up-regulated in GC cells compared to MSCs. The expression of EPH receptor A8 (EPHA8), synovial sarcoma translocation chromosome 18 (SS18), interactor of little elongation complex ELL subunit 1 (ICE1), patched 1 (PTCH1), mutS homolog 3 (MSH3) and caspase recruitment domain family member 11 (CARD11) were also shown to be altered in GC cells in the cBioPortal for Cancer Genomics analysis. 3D complex structures were reported for E-cadherin 1 (CDH1), lymphoid enhancer binding factor 1 (LEF1), transcription factor 7 like 2 (TCF7L2) and adenomatous polyposis coli protein (APC) with β-catenin.

CONCLUSION

The results indicate that the epithelial-mesenchymal transition (EMT)-related gene CTNNB1 plays an important role in the regulation of stem cell pluripotency and cancer signaling.

Wnt5a Increases Properties of Lung Cancer Stem Cells and Resistance to Cisplatin through Activation of Wnt5a/PKC Signaling Pathway

The development of chemoresistance to cisplatin regimens causes a poor prognosis in patients with advanced NSCLC. The role of noncanonical Wnt signaling in the regulation of properties of lung cancer stem cells and chemoresistance was interrogated, by accessing capacities of cell proliferation, migration, invasion, and clonogenicity as well as the apoptosis in A549 cell lines and cisplatin-resistant A549 cells treated with Wnt5a conditional medium or protein kinase C (PKC) inhibitor GF109203X. Results showed that the noncanonical Wnt signaling ligand, Wnt5a, could promote the proliferation, migration, invasion, and colony formation in A549 lung adenocarcinoma cells and cisplatin-resistant A549/DDP cells and increase the fraction of ALDH-positive cell in A549/DDP cells. An exposure of cells to Wnt5a led to a significant reduction of A549/DDP cell apoptosis but not A549 cells. An addition of GF109203X could both strikingly increase the baseline apoptosis and resensitize the Wnt5a-inhibited cell apoptosis. Interestingly, an inhibition of Wnt/PKC signaling pathway could reduce properties of lung cancer stem cells, promote cell apoptosis, and resensitize cisplatin-resistant cells to cisplatin via a caspase/AIF-dependent pathway. These data thus suggested that the Wnt5a could promote lung cancer cell mobility and cisplatin-resistance through a Wnt/PKC signaling pathway and a blockage of this signaling may be an alternative therapeutic strategy for NSCLC patients with resistance to chemotherapies.

KIF3A binds to β-arrestin for suppressing Wnt/β-catenin signalling independently of primary cilia in lung cancer

Aberrant Wnt/β-catenin signalling is implicated in the progression of several human cancers, including non-small cell lung cancer (NSCLC). However, mutations in Wnt/β-catenin pathway components are uncommon in NSCLC, and their epigenetic control remains unclear. Here, we show that KIF3A, a member of the kinesin-2 family, plays a role in suppressing Wnt/β-catenin signalling in NSCLC cells. KIF3A knockdown increases both β-catenin levels and transcriptional activity with concomitant promotion of malignant potential, such as increased proliferation and migration and upregulation of stemness markers. Because KIF3A binds β-arrestin, KIF3A depletion allows β-arrestin to form a complex with DVL2 and axin, stabilizing β-catenin. Although primary cilia, whose biogenesis requires KIF3A, are thought to restrain the Wnt response, pharmacological inhibition of ciliogenesis failed to increase β-catenin activity in NSCLC cells. A correlation between KIF3A loss and a poorer NSCLC prognosis as well as β-catenin and cyclin D1 upregulation further suggests that KIF3A suppresses Wnt/β-catenin signalling and tumourigenesis in NSCLC.

Association of Wnt signaling pathway genetic variants in gallbladder cancer susceptibility and survival

Gallbladder cancer (GBC) is the most common malignancy of the biliary tract with adverse prognosis and poor survival. Wnt signaling plays an important role in embryonic development and regeneration of tissues in all the species. Deregulation of expression and mutations in this pathway may lead to disease state such as cancer. In this study, we assessed the association of common germline variants of Wnt pathway genes (SFRP2, SFRP4, DKK2, DKK3, WISP3, APC, β-catenin, AXIN-2, GLI-1) to evaluate their contribution in predisposition to GBC and treatment outcomes. The study included 564 GBC patients and 250 controls. Out of 564, 200 patients were followed up for treatment response and survival. Tumor response (RECIST 1.1) was recorded in 116 patients undergoing non-adjuvant chemotherapy (NACT). Survival was assessed by Kaplan-Meier curve and Cox-proportional hazard regression. Single locus analysis showed significant association of SFRP4 rs1802073G > T [p value = 0.0001], DKK2 rs17037102C > T [p value = 0.0001], DKK3 rs3206824C > T [p value = 0.012], APC rs4595552 A/T [p value = 0.021], APC rs11954856G > T [p value = 0.047], AXIN-2 rs4791171C > T [p value = 0.001], β-catenin rs4135385A > G [p value = 0.031], and GLI-1 rs222826C > G [p value = 0.001] with increased risk of GBC. Gene-gene interaction using GMDR analysis predicted APC rs11954856 and AXIN2 rs4791171 as significant in conferring GBC susceptibility. Cox-proportional hazard model showed GLI-1 rs2228226 CG/GG and AXIN-2 rs4791171 TT genotype higher hazard ratio. In recursive partitioning, AXIN-2 rs4791171 TT genotype showed higher mortality and hazard. Most of studied genetic variants influence GBC susceptibility. APC rs11954856, GLI-1 rs2228226, and AXIN-2 rs4791171 were found to be associated with poor survival in advanced GBC patients.

Norcantharidin inhibits Wnt signal pathway via promoter demethylation of WIF-1 in human non-small cell lung cancer

Wingless-type (Wnt) family of secreted glycoproteins is a group of signal molecules implicated in oncogenesis. Abnormal activation of Wnt signal pathway is associated with a variety of human cancers, including non-small cell lung cancer (NSCLC). Wnt antagonists, such as the secreted frizzled-related protein (SFRP) family, Wnt inhibitory factor-1 (WIF-1) and cerberus, inhibit Wnt signal pathway by directly binding to Wnt molecules. Norcantharidin (NCTD) is known to possess anticancer activity but less nephrotoxicity than cantharidin. In this study, we found that NCTD inhibited cell proliferation, induced apoptosis, arrested cell cycle and suppressed cell invasion/migration in vitro. Additionally, Wnt signal pathway transcription was also suppressed. NCTD treatment blocked cytoplasmic translocation of beta-catenin into the nucleus. Alterations of apoptosis-related proteins, such as Bax, cleaved caspase-3 (pro-apoptotic) and Bcl-2 (anti-apoptotic), had been detected. Furthermore, the expression levels of WIF-1 and SFRP1 were significantly increased in NCTD-treated groups compared with negative control (NC) groups. Abnormal methylation was observed in NC groups, while NCTD treatment promoted WIF-1 demethylation. The present study revealed that NCTD activated WIF-1 via promoter demethylation, inhibiting the canonical Wnt signal pathway in NSCLC, which may present a new therapeutic target in vivo.

Diagnostic value of SFRP1 as a favorable predictive and prognostic biomarker in patients with prostate cancer

Growing genetic and molecular biological evidence suggests that the disruption of balance between Secreted Frizzled-Related Protein-1 (SFRP1) and β-catenin plays an important role in the initiation and development of multiple cancers. The aim of this study was to examine whether the expression of SFRP1 and β-catenin is associated with the clinical-pathologic features of patients with prostate cancer (PCa), and to evaluate their potential roles as predictive and prognostic biomarkers. In this study, a total of 61 patients with PCa and 10 patients with benign prostatic hyperplasia were included, and we showed that the expression of SFRP1 and β-catenin was correlated with the Gleason score, survival rate and response for endocrine therapy of PCa. The survival rates of PCa patients with low SFRP1 expression (P = 0.016) or high β-catenin expression (P = 0.004) were significantly poorer. A negative correlation (r = -0.275, P = 0.032) between SFRP1 and β-catenin was observed by Chi-square test. Multivariate analysis suggested that SFRP1 (hazard ratio, 0.429; 95% confidence intervals, 0.227–0.812; P = 0.009) may serve as an independent predictive and prognostic factor for PCa. We also showed that the protein and mRNA levels of SFRP1 in androgen-dependent PCa cell line LNCaP were significantly higher than those in androgen-independent PCa cell lines DU145 and PC3. However, the protein level of β-catenin in LNCaP cells was significantly lower than that in DU145 and PC3 cells, and no significant difference of β-catenin mRNA level was observed in LNCaP, DU145 and PC3 cells. Bisulfite sequencing PCR assay revealed significantly lower methylation level of SFRP1 promoter in LNCaP cells than that in DU145 and PC3 cells. Taken together, these findings suggest that SFRP1, which expression inversely correlates with that of β-catenin, is a favorable predictive and prognostic biomarker.

The Wnt/β-catenin pathway in human fibrotic-like diseases and its eligibility as a therapeutic target

The canonical Wnt signaling pathway is involved in a variety of biological processes like cell proliferation, cell polarity, and cell fate determination. This pathway has been extensively investigated as its deregulation is linked to different diseases, including various types of cancer, skeletal defects, birth defect disorders (including neural tube defects), metabolic diseases, neurodegenerative disorders and several fibrotic diseases like desmoid tumors. In the "on state", beta-catenin, the key effector of Wnt signaling, enters the nucleus where it binds to the members of the TCF-LEF family of transcription factors and exerts its effect on gene transcription. Disease development can be caused by direct or indirect alterations of the Wnt/β-catenin signaling.

In the first case germline or somatic mutations of the Wnt components are associated to several diseases such as the familial adenomatous polyposis (FAP) - caused by germline mutations of the tumor suppressor adenomatous polyposis coli gene (APC) - and the desmoid-like fibromatosis, a sporadic tumor associated with somatic mutations of the β-catenin gene (CTNNB1).

In the second case, epigenetic modifications and microenvironmental factors have been demonstrated to play a key role in Wnt pathway activation. The natural autocrine Wnt signaling acts through agonists and antagonists competing for the Wnt receptors. Anomalies in this regulation, whichever is their etiology, are an important part in the pathogenesis of Wnt pathway linked diseases. An example is promoter hypermethylation of Wnt antagonists, such as SFRPs, that causes gene silencing preventing their function and consequently leading to the activation of the Wnt pathway. Microenvironmental factors, such as the extracellular matrix, growth factors and inflammatory mediators, represent another type of indirect mechanism that influence Wnt pathway activation. A favorable microenvironment can lead to aberrant fibroblasts activation and accumulation of ECM proteins with subsequent tissue fibrosis that can evolve in fibrotic disease or tumor.

Since the development and progression of several diseases is the outcome of the Wnt pathway cross-talk with other signaling pathways and inflammatory factors, it is important to consider not only direct inhibitors of the Wnt signaling pathway but also inhibitors of microenvironmental factors as promising therapeutic approaches for several tumors of fibrotic origin.

The Wnt/β-catenin pathway in human fibrotic-like diseases and its eligibility as a therapeutic target

The canonical Wnt signaling pathway is involved in a variety of biological processes like cell proliferation, cell polarity, and cell fate determination. This pathway has been extensively investigated as its deregulation is linked to different diseases, including various types of cancer, skeletal defects, birth defect disorders (including neural tube defects), metabolic diseases, neurodegenerative disorders and several fibrotic diseases like desmoid tumors. In the "on state", beta-catenin, the key effector of Wnt signaling, enters the nucleus where it binds to the members of the TCF-LEF family of transcription factors and exerts its effect on gene transcription. Disease development can be caused by direct or indirect alterations of the Wnt/β-catenin signaling. In the first case germline or somatic mutations of the Wnt components are associated to several diseases such as the familial adenomatous polyposis (FAP) - caused by germline mutations of the tumor suppressor adenomatous polyposis coli gene (APC) - and the desmoid-like fibromatosis, a sporadic tumor associated with somatic mutations of the β-catenin gene (CTNNB1). In the second case, epigenetic modifications and microenvironmental factors have been demonstrated to play a key role in Wnt pathway activation. The natural autocrine Wnt signaling acts through agonists and antagonists competing for the Wnt receptors. Anomalies in this regulation, whichever is their etiology, are an important part in the pathogenesis of Wnt pathway linked diseases. An example is promoter hypermethylation of Wnt antagonists, such as SFRPs, that causes gene silencing preventing their function and consequently leading to the activation of the Wnt pathway. Microenvironmental factors, such as the extracellular matrix, growth factors and inflammatory mediators, represent another type of indirect mechanism that influence Wnt pathway activation. A favorable microenvironment can lead to aberrant fibroblasts activation and accumulation of ECM proteins with subsequent tissue fibrosis that can evolve in fibrotic disease or tumor. Since the development and progression of several diseases is the outcome of the Wnt pathway cross-talk with other signaling pathways and inflammatory factors, it is important to consider not only direct inhibitors of the Wnt signaling pathway but also inhibitors of microenvironmental factors as promising therapeutic approaches for several tumors of fibrotic origin.