Wnt3a/β-Catenin Signaling Conditions Differentiation of Partially Exhausted T-effector Cells in Human Cancers

Wnt signaling and tumors (Review)

Wnt signaling is a highly conserved evolutionary pathway that plays a key role in regulation of embryonic development, as well as tissue homeostasis and regeneration. Abnormalities in Wnt signaling are associated with tumorigenesis and development, leading to poor prognosis in patients with cancer. However, the pharmacological effects and mechanisms underlying Wnt signaling and its inhibition in cancer treatment remain unclear. In addition, potential side effects of inhibiting this process are not well understood. Therefore, the present review outlines the role of Wnt signaling in tumorigenesis, development, metastasis, cancer stem cells, radiotherapy resistance and tumor immunity. The present review further identifies inhibitors that target Wnt signaling to provide a potential novel direction for cancer treatment. This may facilitate early application of safe and effective drugs targeting Wnt signaling in clinical settings. An in-depth understanding of the mechanisms underlying inhibition of Wnt signaling may improve the prognosis of patients with cancer.

An endothelial-related prognostic index for bladder cancer patients

BACKGROUND

Within the tumor microenvironment, endothelial cells hold substantial sway over bladder cancer (BC) prognosis. Herein, we aim to elucidate the impact of endothelial cells on BC patient outcomes by employing an integration of single-cell and bulk RNA sequencing data.

METHODS

All data utilized in this study were procured from online databases. R version 3.6.3 and relevant packages were harnessed for the development and validation of an endothelial-associated prognostic index (EPI).

RESULTS

EPI was formulated, incorporating six genes (CYTL1, FAM43A, GSN, HSPG2, RBP7, and SLC2A3). EPI demonstrated significant prognostic value in both The Cancer Genome Atlas (TCGA) and externally validated dataset. Functional results revealed a profound association between EPI and endothelial cell functionality, as well as immune-related processes. Our findings suggest that patients with low-risk EPI scores are more likely to respond positively to immunotherapy, as indicated by immune checkpoint activity, immune infiltration, tumor mutational burden, stemness index, TIDE, and IMvigor210 analyses. Conversely, individuals with high-risk EPI scores exhibited heightened sensitivity to cisplatin, docetaxel, and gemcitabine treatment regimens.

CONCLUSION

We have effectively discerned pivotal genes from the endothelial cell perspective and constructed an EPI for BC patients, thereby offering promising prospects for precision medicine.

LAIR1-mediated resistance of hepatocellular carcinoma cells to T cells through a GSK-3β/β-catenin/MYC/PD-L1 pathway

BACKGROUND

An increasing number of studies have reported the involvement of oncogenes in the regulation of the immune system. LAIR1 is an immunosuppressive molecule and its role in immune-related diseases has been mainly reported. To date, it is unclear whether LAIR1 in tumor cells is involved in immune regulation. Therefore, the aim of this study was to investigate the role of LAIR1 in the immune microenvironment of hepatocellular carcinoma (HCC) to seek the novel therapeutic discoveries.

METHODS

Tumor Immune Dysfunction and Exclusion database was used to predict the response of LAIR1 expression to immune checkpoint blockade. CD8+ T cells were co-cultured with HCC cells, and the killing efficiency of leukocytes on HCC cells was detected by flow cytometry. Flow cytometry was also used to detect the expression of inhibitory receptors. In addition, Western blot, immunofluorescence, and nucleus/cytoplasm fractionation experiments were performed to explore the molecular mechanisms by which LAIR1 created a suppressive tumor microenvironment.

RESULTS

LAIR1 expression in HCC was associated with worse immune prognosis and T-cell dysfunction. HCC cells overexpressing LAIR1 co-cultured with CD8+ T cells induced exhaustion of latter. Mechanism studies indicated that LAIR1 in HCC cells up-regulated the phosphorylation of β-catenin by inducing the phosphorylation of GSK-3β, leading to the impairment of the expression and the nuclear localization signal of β-catenin. Low β-catenin expression and nuclear localization signal inhibited MYC-mediated PD-L1 expression. Therefore, PD-L1 up-regulated by LAIR1 caused the exhaustion of infiltrating CD8+ T cells in HCC, which aggravated the malignant progression of HCC.

CONCLUSION

LAIR1 increased PD-L1 expression through the GSK-3β/β-catenin/MYC/PD-L1 pathway and promoted immune evasion of HCC cells. Targeted inhibition of LAIR1 helped to enhance the immune killing effect of CD8+ T cells in HCC.

Cells of the tumor microenvironment speak the Wnt language

Wnt signaling plays numerous functions in cancer, from primary transformation and tumor growth to metastasis. In addition to these cancer cell-intrinsic functions, Wnt signaling emerges to critically control cross-communication among cancer cells and the tumor microenvironment (TME). Here, we summarize the evidence that not only multiple cancer cell types, but also cells constituting the TME 'speak the Wnt language'. Fibroblasts, macrophages, endothelia, and lymphocytes all use the Wnt language to convey messages to and from cancer cells and among themselves; these messages are important for tumor progression and fate. Decoding this language will advance our understanding of tumor biology and unveil novel therapeutic avenues.

Molecular subtype identification and signature construction based on Golgi apparatus-related genes for better prediction prognosis and immunotherapy response in hepatocellular carcinoma

Introduction

The Golgi apparatus (GA) is the center of protein and lipid synthesis and modification in normal cells and is involved in regulating various cellular process as a signaling hub, the dysfunction of which can lead to the development of various pathological conditions, including tumors. Mutations in Golgi apparatus-related genes (GARGs) are prevalent in most tumors, and their mutations can make them pro-tumor metastatic. The aim of this study was to analyze the predictive role of GARGs in the prognosis and immunotherapeutic outcome of hepatocellular carcinoma.

Methods

We used TCGA, GEO and ICGC databases to classify hepatocellular carcinoma samples into two molecular subtypes based on the expression of GARGs. Signature construction was then performed using GARGs, and signature genes were selected for expression validation and tumor phenotype experiments to determine the role of GARGs in the prognosis of hepatocellular carcinoma.

Results

Using the TCGA, GEO and ICGC databases, two major subtypes of molecular heterogeneity among hepatocellular carcinoma tumors were identified based on the expression of GARGs, C1 as a high-risk subtype (low survival) and C2 as a low-risk subtype (high survival). The high-risk subtype had lower StromalScore, ImmuneScore, ESTIMATEScore and higher TumorPurity, indicating poorer treatment outcome for ICI. Meanwhile, we constructed a new risk assessment profile for hepatocellular carcinoma based on GARGs, and we found that the high-risk group had a worse prognosis, a higher risk of immune escape, and a higher TP53 mutation rate. Meanwhile, TME analysis showed higher tumor purity TumorPurity and lower ESTIMATEScore, ImmuneScore and StromalScore in the high-risk group. We also found that the high-risk group responded more strongly to a variety of anticancer drugs, which is useful for guiding clinical drug use. Meanwhile, the expression of BSG was experimentally found to be associated with poor prognosis of HCC. After interfering with the expression of BSG in HCC cells SMMC-7721, the proliferation and migration ability of HCC cells were significantly restricted.

Discussion

The signature we constructed using GARGs can well predict the prognosis and immunotherapy effect of hepatocellular carcinoma, providing new ideas and strategies for the treatment of hepatocellular carcinoma.

The Roles of Secreted Wnt Ligands in Cancer

Wnt ligands are secreted signaling proteins that display a wide range of biological effects. They play key roles in stimulating Wnt signaling pathways to facilitate processes such as tissue homeostasis and regeneration. Dysregulation of Wnt signaling is a hallmark of many cancers and genetic alterations in various Wnt signaling components, which result in ligand-independent or ligand-dependent hyperactivation of the pathway that have been identified. Recently, research is focusing on the impact of Wnt signaling on the interaction between tumor cells and their micro-environment. This Wnt-mediated crosstalk can act either in a tumor promoting or suppressing fashion. In this review, we comprehensively outline the function of Wnt ligands in different tumor entities and their impact on key phenotypes, including cancer stemness, drug resistance, metastasis, and immune evasion. Lastly, we elaborate approaches to target Wnt ligands in cancer therapy.

Wnt3a is a promising target in colorectal cancer

Most colorectal cancers (CRC) are associated with activated Wnt signaling, making it the fourth most prevalent type of cancer globally. To function properly, the Wnt signaling pathway requires secreted glycoproteins known as Wnt ligands (Wnts). Humans have 19 Wnts, which suggest a complicated signaling and biological process, and we still know little about their functions in developing CRC. This review aims to describe the canonical Wnt signaling in CRC, particularly the Wnt3a expression pattern, and their association with the angiogenesis and progression of CRC. This review also sheds light on the inhibition of Wnt3a signaling in CRC. Despite some obstacles, a thorough understanding of Wnts is essential for effectively managing CRC.

Dance of The Golgi: Understanding Golgi Dynamics in Cancer Metastasis

The Golgi apparatus is at the center of protein processing and trafficking in normal cells. Under pathological conditions, such as in cancer, aberrant Golgi dynamics alter the tumor microenvironment and the immune landscape, which enhances the invasive and metastatic potential of cancer cells. Among these changes in the Golgi in cancer include altered Golgi orientation and morphology that contribute to atypical Golgi function in protein trafficking, post-translational modification, and exocytosis. Golgi-associated gene mutations are ubiquitous across most cancers and are responsible for modifying Golgi function to become pro-metastatic. The pharmacological targeting of the Golgi or its associated genes has been difficult in the clinic; thus, studying the Golgi and its role in cancer is critical to developing novel therapeutic agents that limit cancer progression and metastasis. In this review, we aim to discuss how disrupted Golgi function in cancer cells promotes invasion and metastasis.

T Cell Memory in Infection, Cancer, and Autoimmunity

Long-term immunological memory represents a unique performance of the adaptive immunity selected during evolution to support long-term survival of species in vertebrates, through protection against dangerous "invaders", namely, infectious agents or unwanted (e.g., tumor) cells. The balance between the development of T cell memory and various mechanisms of immunoregulation (namely, T cell effector exhaustion and regulatory T cell suppression) dictates the fate in providing protection or not in different conditions, such as (acute or chronic) infection, vaccination, cancer, and autoimmunity. Here, these different environments are taken in consideration to outline the up-to-date cellular and molecular features regulating the development or damping of immunological memory and to delineate therapeutic strategies capable to improve or control it, in order to address pathological contexts, such as infection, tumor, and autoimmunity.

Wnt signaling pathway in cancer immunotherapy

Wnt/β-catenin signaling is a highly conserved pathway that regulates cell proliferation, differentiation, apoptosis, stem cell self-renewal, tissue homeostasis, and wound healing. Dysregulation of the Wnt pathway is intricately involved in almost all stages of tumorigenesis in various cancers. Through direct and/or indirect effects on effector T cells, T-regulatory cells, T-helper cells, dendritic cells, and other cytokine-expressing immune cells, abnormal activation of Wnt/β-catenin signaling benefits immune exclusion and hinders T-cell-mediated antitumor immune responses. Activation of Wnt signaling results in increased resistance to immunotherapies. In this review, we summarize the process by which Wnt signaling affects cancer and immune surveillance, and the potential for targeting the Wnt-signaling pathway via cancer immunotherapy.

Current Perspectives on the Immunosuppressive Niche and Role of Fibrosis in Hepatocellular Carcinoma and the Development of Antitumor Immunity

Immune checkpoint inhibitors have become the mainstay of treatment for hepatocellular carcinoma (HCC). However, they are ineffective in some cases. Previous studies have reported that genetic alterations in oncogenic pathways such as Wnt/β-catenin are the important triggers in HCC for primary refractoriness. T-cell exhaustion has been reported in various tumors and is likely to play a prominent role in the emergence of HCC due to chronic inflammation and cirrhosis-associated immune dysfunction. Immunosuppressive cells including regulatory T-cells and tumor-associated macrophages infiltrating the tumor are associated with hyperprogressive disease in the early stages of immune checkpoint inhibitor treatment. In addition, stellate cells and tumor-associated fibroblasts create an abundant desmoplastic environment by producing extracellular matrix. This strongly contributes to epithelial to mesenchymal transition via signaling activities including transforming growth factor beta, Wnt/β-catenin, and Hippo pathway. The abundant desmoplastic environment has been demonstrated in pancreatic ductal adenocarcinoma and cholangiocarcinoma to suppress cytotoxic T-cell infiltration, PD-L1 expression, and neoantigen expression, resulting in a highly immunosuppressive niche. It is possible that a similar immunosuppressive environment is created in HCC with advanced fibrosis in the background liver. Although sufficient understanding is required for the establishment of immune therapies of HCC, further investigations are still required in this field.

Therapeutic Effects of Polyphenols on the Treatment of Colorectal Cancer by Regulating Wnt β-Catenin Signaling Pathway

Colorectal cancer (CRC) is the third most common cause of cancer-related death worldwide in terms of both its rates of incidence and mortality. Due to serious side effects associated with conventional chemotherapeutic treatments, many natural products with fewer adverse side effects have been considered as potential treatment options. In fact, many natural products have widely been used in various phases of clinical trials for CRC, as well as in in vitro and in vivo preclinical studies. Curcumin (CUR) and resveratrol (RES) are classified as natural polyphenolic compounds that have been demonstrated to have anticancer activity against CRC and are associated with minimal side effects. By regulating select target genes involved in several key signaling pathways in CRC, in particular, the Wnt β-catenin signaling cascade, the course of CRC may be positively altered. In the current review, we focused on the therapeutic effects of CUR and RES in CRC as they pertain to modulation of the Wnt β-catenin signaling pathway.

Progression on the Roles and Mechanisms of Tumor-Infiltrating T Lymphocytes in Patients With Hepatocellular Carcinoma

Primary liver cancer (PLC) is one of the most common malignancies in China, where it ranks second in mortality and fifth in morbidity. Currently, liver transplantation, hepatic tumor resection, radiofrequency ablation, and molecular-targeted agents are the major treatments for hepatocellular carcinoma (HCC). Overall, HCC has a poor survival rate and a high recurrence rate. Tumor-infiltrating lymphocytes (TILs) have been discovered to play essential roles in the development, prognosis, and immunotherapy treatment of HCC. As the major component cells of TILs, T cells are also proved to show antitumor and protumor effects in HCC. Foxp3+, CD8+, CD3+, and CD4+ T lymphocytes are the broadly studied subgroups of TILs. This article reviews the roles and mechanisms of different tumor-infiltrating T lymphocyte subtypes in HCC.

Taking the road less traveled - the therapeutic potential of CBP/β-catenin antagonists

AREAS COVERED

This perspective discusses the challenges of targeting the Wnt signaling cascade, the safety, efficacy, and therapeutic potential of specific CBP/β-catenin antagonists and a rationale for the pleiotropic effects of CBP/β-catenin antagonists beyond Wnt signaling.

EXPERT OPINION

CBP/β-catenin antagonists can correct lineage infidelity, enhance wound healing, both normal and aberrant (e.g. fibrosis) and force the differentiation and lineage commitment of stem cells and cancer stem cells by regulating enhancer and super-enhancer coactivator occupancy. Small molecule CBP/β-catenin antagonists rebalance the equilibrium between CBP/β-catenin versus p300/β-catenin dependent transcription and may be able to treat or prevent many diseases of aging, via maintenance of our somatic stem cell pool, and regulating mitochondrial function and metabolism involved in differentiation and immune cell function.

Role of Oncogenic Pathways on the Cancer Immunosuppressive Microenvironment and Its Clinical Implications in Hepatocellular Carcinoma

The tumor immune microenvironment, including hepatocellular carcinoma (HCC), is complex, consisting of crosstalk among tumor components such as the cancer cells, stromal cells and immune cells. It is conceivable that phenotypic changes in cancer cells by genetic and epigenetic alterations affect the cancer-stroma interaction and anti-cancer immunity through the expression of immune checkpoint molecules, growth factors, cytokines, chemokines and metabolites that may act on the immune system in tumors. Therefore, predicting the outcome of ICI therapy requires a thorough understanding of the oncogenic signaling pathways in cancer and how they affect tumor immune evasion. In this review, we have detailed how oncogenic signaling pathways can play a role in altering the condition of the cellular components of the tumor immune microenvironment such as tumor-associated macrophages, regulatory T cells and myeloid-derived suppressor cells. The RAS/MAPK, PI3K/Akt, Wnt/β-catenin and JAK/STAT pathways have all been implicated in anti-tumor immunity. We also found that factors that reflect the immune microenvironment of the tumor, including the status of oncogenic pathways such as the volume of tumor-infiltrating T cells, expression of the immune checkpoint protein PD-1 and its ligand PD-L1, and activation of the Wnt/β-catenin signaling pathway, predict a response to ICI therapy in HCC cases.

Role of Oncogenic Pathways on the Cancer Immunosuppressive Microenvironment and Its Clinical Implications in Hepatocellular Carcinoma

The tumor immune microenvironment, including hepatocellular carcinoma (HCC), is complex, consisting of crosstalk among tumor components such as the cancer cells, stromal cells and immune cells. It is conceivable that phenotypic changes in cancer cells by genetic and epigenetic alterations affect the cancer-stroma interaction and anti-cancer immunity through the expression of immune checkpoint molecules, growth factors, cytokines, chemokines and metabolites that may act on the immune system in tumors. Therefore, predicting the outcome of ICI therapy requires a thorough understanding of the oncogenic signaling pathways in cancer and how they affect tumor immune evasion. In this review, we have detailed how oncogenic signaling pathways can play a role in altering the condition of the cellular components of the tumor immune microenvironment such as tumor-associated macrophages, regulatory T cells and myeloid-derived suppressor cells. The RAS/MAPK, PI3K/Akt, Wnt/β-catenin and JAK/STAT pathways have all been implicated in anti-tumor immunity. We also found that factors that reflect the immune microenvironment of the tumor, including the status of oncogenic pathways such as the volume of tumor-infiltrating T cells, expression of the immune checkpoint protein PD-1 and its ligand PD-L1, and activation of the Wnt/β-catenin signaling pathway, predict a response to ICI therapy in HCC cases.

Pyrvinium Treatment Confers Hepatic Metabolic Benefits via β-Catenin Downregulation and AMPK Activation

Genetic evidence has indicated that β-catenin plays a vital role in glucose and lipid metabolism. Here, we investigated whether pyrvinium, an anthelmintic agent previously reported as a down-regulator of cellular β-catenin levels, conferred any metabolic advantages in treatment of metabolic disorders. Glucose production and lipid accumulation were analyzed to assess metabolic response to pyrvinium in hepatocytes. The expression of key proteins and genes were assessed by immunoblotting and RT-PCR. The in vivo efficacy of pyrvinium against metabolic disorders was evaluated in the mice fed with a high fat diet (HFD). We found that pyrvinium inhibited glucose production and reduced lipogenesis by decreasing the expression of key genes in hepatocytes, which were partially elicited by the downregulation of β-catenin through AXIN stabilization. Interestingly, the AMPK pathway also played a role in the action of pyrvinium, dependent on AXIN stabilization but independent of β-catenin downregulation. In HFD-fed mice, pyrvinium treatment led to improvement in glucose tolerance, fatty liver disorder, and serum cholesterol levels along with a reduced body weight gain. Our results show that small molecule stabilization of AXIN using pyrvinium may lead to improved glucose and lipid metabolism, via β-catenin downregulation and AMPK activation.

Pharmacologically Targeting the WNT/β-Catenin Signaling Cascade: Avoiding the Sword of Damocles

WNT/β-catenin signaling plays fundamental roles in numerous developmental processes and in adult tissue homeostasis and repair after injury, by controlling cellular self-renewal, activation, division, differentiation, movement, genetic stability, and apoptosis. As such, it comes as no surprise that dysregulation of WNT/β-catenin signaling is associated with various diseases, including cancer, fibrosis, neurodegeneration, etc. Although multiple agents that specifically target the WNT/β-catenin signaling pathway have been studied preclinically and a number have entered clinical trials, none has been approved by the FDA to date. In this chapter, we provide our insights as to the reason(s) it has been so difficult to safely pharmacologically target the WNT/β-catenin signaling pathway and discuss the significant efforts undertaken towards this goal.

Genetically driven CD39 expression shapes human tumor-infiltrating CD8+ T-cell functions

In our study, we investigated the role of CD39 on tumor-infiltrating CD8+ T lymphocytes (CD8+ TILs) in colorectal, head and neck and pancreatic cancers. Partially confirming recent observations correlating the CD39 expression with T-cell exhaustion, we demonstrated a divergent functional activity in CD39+ CD8+ TILs. On the one hand, CD39+ CD8+ TILs (as compared to their CD39- counterparts) produced significantly lower IFN-γ and IL-2 amounts, expressed higher PD-1, and inversely correlated with perforin and granzyme B expression. On the other, they displayed a significantly higher proliferative capacity ex vivo that was inversely correlated with the PD-1 expression. Therefore, CD39+ CD8+ TILs, including those co-expressing the CD103 (a marker of T resident memory [TRM] cells), were defined as partially dysfunctional T cells that correlate with tumor patients with initial progression stages. Interestingly, our results identified for the first time a single nucleotide polymorphism (SNP rs10748643 A>G), as a genetic factor associated with CD39 expression in CD8+ TILs. Finally, we demonstrated that compounds inhibiting CD39-related ATPases improved CD39+ CD8+ T-cell effector function ex vivo, and that CD39+ CD8+ TILs displayed effective suppression function in vitro. Overall these data suggest that the SNP analysis may represent a suitable predictor of CD39+ CD8+ T-cell expression in cancer patients, and propose the modulation of CD39 as a new strategy to restore partially exhausted CD8+ TILs.

Differential gene expression of tumor-infiltrating CD4+ T cells in advanced versus early stage colorectal cancer and identification of a gene signature of poor prognosis

Tumor-infiltrating lymphocytes (TILs) play indispensable roles in the progression and response to treatment of solid tumors. However, the prognostic significance of CD4⁺ TILs is not fully disclosed in cancers generally and in CRC in particular, mainly due to the existence of different functional subsets of CD4⁺ T cells. We performed transcriptomic profiling of CD4⁺ TILs isolated from CRC patients in order to identify differentially expressed genes and their functional pathways in early versus advanced disease stages. We found that in advanced stages, genes related to immune and inflammatory responses, in particular Th1-mediated immune response and cytotoxicity-mediated genes, were downregulated; while epigenetic-mediated silencing genes were upregulated. Interestingly, we identified genes, which were steadily upregulated or downregulated in CD4⁺ TILs with CRC progression from stage I to IV. Additionally, of the top 200 deregulated genes, 43 upregulated and 64 downregulated genes showed similar deregulation trends in the cancer genome atlas CRC dataset. From these 97 deregulated genes, we identified a “poor prognosis CD4 gene signature (ppCD4sig)”. Patients with high ppCD4sig score showed shorter disease-specific survival (DSS) and progression-free interval (PFI). The ppCD4sig was an independent prognostic indicator for DSS (HR = 1.73, 95% CI 1.32–2.27, P = 0.0001) and PFI (HR = 1.75, 95% CI 1.3–2.35, P = 0.0016). Additionally, patients at advanced stages and at a younger age (<55 years) were more likely to have a high ppCD4sig score. Altogether, our data provide novel insights and a unique prognostic gene signature of CD4⁺ TILs in the CRC microenvironment.

Reduced Caudal Type Homeobox 2 (CDX2) Promoter Methylation Is Associated with Curcumin's Suppressive Effects on Epithelial-Mesenchymal Transition in Colorectal Cancer Cells

Background

Curcumin is a component of Curcuma longa with various biological activities. The present study aimed to investigate curcumin’s inhibitory effects on epithelial-mesenchymal transition (EMT) in colorectal cancer (CRC) cells and possible mechanisms of action underlying these effects.

Material/Methods

Human SW480 CRC cells were incubated with curcumin at 0.1, 0.2, 0.4, 0.8, or 1.6 μmol/L. The 3-(4,5-Dimethylthiazol-2-Yl)-2,5-Diphenyltetrazolium Bromide (MTT) assay was utilized to evaluate cell viabilities. The DNA methylation levels of the cdx2 promoter were assessed by bisulfite sequencing polymerase chain reaction (BSP). Real-time quantitative PCR was used to measure the mRNA expression levels. Protein expression levels were evaluated with western blotting. Immunofluorescence staining was used to evaluate the nuclear translocation of β-catenin.

Results

Curcumin concentrations of 0.1, 0.2, and 0.4 μmol/L showed no significant association with the viability of SW480 cells, which were chosen for subsequent experiments. Curcumin incubation significantly downregulated expression levels of DNA methyltransferase1 (DNMT1), DNMT3a, and the methylation levels of the cdx2 promoter in a concentration-dependent manner. The expression levels of N-cadherin, Vimentin, Wnt3a, Snail1, and Twist, as well as the nuclear translocation levels of β-catenin, were reduced in a curcumin concentration-dependent manner. The expression levels of E-cadherin were increased in a curcumin concentration-dependent manner.

Conclusions

Curcumin negatively regulated transcription factors promoting EMT in CRC cells by decreasing cdx2 promoter DNA methylation and consequently suppressing the CDX2/Wnt3a/β-catenin signaling pathway.

Viral Hepatitides, Inflammation and Tumour Microenvironment

In this chapter, we discuss the role of hepatitis B virus (HBV) and hepatitis C virus (HCV) infections in the establishment of hepatocellular carcinoma (HCC), highlighting the key role of the multiple, non-mutually exclusive, pathways involved in the modulation of immune responses and in the orchestration of a chronic low-level inflammation state favouring HCC development. In particular, we discuss (i) HCC as a classical paradigm of inflammation-linked cancer; (ii) the role of the most relevant inflammatory cytokines involved (i.e. IL-6, TNF-α, IL-18, IL-1β, TGF-β IL-10); (iii) the role of T cell exhaustion by immune checkpoints; (iv) the role of the Wnt3a/β-catenin signalling pathway and (v) the role of different subsets of suppressor cells.

Wnt Signaling Cascade in Dendritic Cells and Regulation of Anti-tumor Immunity

Dendritic cells (DCs) control the strength and quality of antigen-specific adaptive immune responses. This is critical for launching a robust immunity against invading pathogens while maintaining a state of tolerance to self-antigens. However, this also represents a fundamental barrier to anti-tumor immune responses and cancer immunotherapy. DCs in the tumor microenvironment (TME) play a key role in this process. The factors in the TME and signaling networks that program DCs to a regulatory state are not fully understood. Recent advances point to novel mechanisms by which the canonical Wnt signaling cascade in DCs regulates immune suppression, and the same pathway in tumors is associated with the evasion of anti-tumor immunity. Here, we review these recent advances in the context of the pleiotropic effects of the Wnts in shaping anti-tumor immune responses by modulating DC functions. In addition, we will discuss how Wnt/β-catenin pathway in DCs can be targeted for successful cancer immunotherapy.

Miltefosine suppression of Pten null T-ALL leukemia via β-catenin degradation through inhibition of pT308-Akt and TGFβ1/Smad3

Pten deletion in the hematopoietic stem cells (HSC) causes a myeloproliferative disorder, which may subsequently develop into a T-cell acute lymphoblastic leukemia (T-ALL). β-catenin expression was dramatically increased in the c-Kit^midCD3⁺Lin^- leukemia stem cells (LSC) and was critical for T-ALL development. Therefore, the inactivation of β-catenin in LSC may have a potential to eliminate the LSC. In this study, we investigated the mechanism of enhancement of the β-catenin expression and subsequently used a drug to inactivate β-catenin expression in T-ALL. Western blot (WB) analysis revealed an increased level of β-catenin in the leukemic cells, but not in the pre-leukemic cells. Furthermore, the WB analysis of the thymic cells from different stages of leukemia development showed that increased expression of β-catenin was not via the pS9-GSK3β signaling, but was dependent on the pT308-Akt activation. Miltefosine (Hexadecylphosphocholine) is the first oral anti-Leishmania drug, which is a phospholipid agent and has been shown to inhibit the PI3K/Akt activity. Treatment of the Pten^Δ/Δ leukemic mice with Miltefosine for different durations demonstrated that the pT308-Akt and the β-catenin expressions were inhibited in the leukemia blast cells. Miltefosine treatment also suppressed the TGFβ1/Smad3 signaling pathway. Analysis of TGFβ1 in the sorted subpopulations of the blast cells showed that TGFβ1 was secreted by the CD3⁺CD4^- subpopulation and may exert effects on the subpopulations of both CD3⁺CD4⁺ and CD3⁺CD4^- leukemia blast cells. When a TGFβR1 inhibitor, SB431542 was injected into the Pten^Δ/Δ leukemic mice, the Smad3 and β-catenin expressions were down-regulated. On the basis of the results, we conclude that Miltefosine can suppress leukemia by degrading β-catenin through repression of the pT308-Akt and TGFβ1/Smad3 signaling pathways. This study demonstrates a possibility to inhibit Pten loss-associated leukemia genesis via targeting Akt and Smad3.

Emerging Roles of Wnt Ligands in Human Colorectal Cancer

Colorectal cancer (CRC) is the fourth leading cause of cancer death worldwide, and constitutive activation of the Wnt signaling pathway is universal in most CRC cases. Wnt ligands (Wnts) are secreted glycoproteins and fundamentally essential for the transduction of Wnt signaling pathway. However, the 19 members of Wnts in humans imply a daunting complexity of Wnt signaling and biological effects, and our understanding of their roles in CRC tumorigenesis is still quite rudimentary. This review will give an overview of the structural characteristics and maturation process of Wnts. The expression pattern of all human Wnts in CRC tissues, including Wnt1, Wnt2, Wnt2b, Wnt3, Wnt3a, Wnt4, Wnt5a, Wnt5b, Wnt6, Wnt7a, Wnt7b, Wnt8a, Wnt8b, Wnt9a, Wnt9b, Wnt10a, Wnt10b, Wnt11, and Wnt16, and their relationship with the tumorigenesis and the progression of CRC will be specifically summarized separately. Despite certain challenges, Wnt-based therapeutics for CRC emerge continuously and some are now in clinical trials. In conclusion, a deep understanding of Wnts is very helpful for a better management of this disease.

Enhanced Kat3A/Catenin transcription: a common mechanism of therapeutic resistance

Cancers are heterogeneous at the cellular level. Cancer stem cells/tumor initiating cells (CSC/TIC) both initiate tumorigenesis and are responsible for therapeutic resistance and disease relapse. Elimination of CSC/TIC should therefore be able to reverse therapy resistance. In principle, this could be accomplished by either targeting cancer stem cell surface markers or "stemness" pathways. Although the successful therapeutic elimination of "cancer stemness" is a critical goal, it is complex in that it should be achieved without depletion of or increases in somatic mutations in normal tissue stem cell populations. In this perspective, we will discuss the prospects for this goal via pharmacologically targeting differential Kat3 coactivator/Catenin usage, a fundamental transcriptional control mechanism in stem cell biology.

Wnt1 Promotes EAAT2 Expression and Mediates the Protective Effects of Astrocytes on Dopaminergic Cells in Parkinson's Disease

Background

Wnt/β-catenin signaling has been reported to exert cytoprotective effects in a cellular model of Parkinson's disease (PD). Glutamate excitotoxicity has been suggested to contribute to the pathogenesis of PD, and excitatory amino acid transporters (EAATs) play a predominant role in clearing excessive glutamate. EAAT2 is mainly expressed in astrocytes, which are an important source of Wnt signaling in the brain.

Methods

Wnt1-overexpressing U251 astrocytes were indirectly cocultured with dopaminergic SH-SY5Y cells treated with 6-hydroxydopamine (6-OHDA). Cell toxicity was determined by cell viability and flow cytometric detection. Glutamate level in the culture medium was determined by enzyme-linked immunosorbent assay (ELISA). Western blot analysis was used to detect the expression of Wnt1, β-catenin, and EAAT2. Immunofluorescence was used to display the expression and translocation of NF-κB p65.

Results

6-OHDA treatment significantly decreased cell viability in both U251 cells and SH-SY5Y cells, inhibited the expression of Wnt1, β-catenin, and EAAT2 in U251 cells, and increased the glutamate level in the culture medium. Coculture with Wnt1-overexpressing U251 cells attenuated 6-OHDA-induced apoptosis in SH-SY5Y cells. Overexpression of Wnt1 decreased the glutamate level in the culture media, upregulated β-catenin, EAAT2, and NF-κB levels, and promoted the translocation of NF-κB from the cytoplasm to the nucleus in U251 cells.

Conclusion

Wnt1 promoted EAAT2 expression and mediated the cytoprotective effects of astrocytes on dopaminergic cells. NF-κB might be involved in the regulation of EAAT2 by Wnt1.

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-195 restrains lung adenocarcinoma by regulating CD4+ T cell activation via the CCDC88C/Wnt signaling pathway: a study based on the Cancer Genome Atlas (TCGA), Gene Expression Omnibus (GEO) and bioinformatic analysis

Background

To systematically identity microRNA signatures, as well as miRNA-gene axes, for lung adenocarcinoma (LUAD) and to explore the potential biomarkers and mechanisms associated with the LUAD immune responses.

Methods

LUAD-related data were obtained from the Gene Expression Omnibus (GEO) and The Cancer Genome Atlas (TCGA), and these data were then used to identify the differentially expressed miRNAs that were downregulated in tumor tissues. Summary receiver operating characteristic curve analysis, survival analysis and meta-analysis were applied to evaluate the clinical significance and diagnostic value of the identified miRNAs. The presumed targets of the integrated-signature miRNAs were identified via 3 different target prediction algorithms: TargetScan, miRDB and DIANA-TarBase. Immunologic signature gene sets were enriched by gene set enrichment analysis (GSEA). Tumor-infiltrating lymphocytes were profiled by the Tumor IMmune Estimation Resource (TIMER). After pathway enrichment analysis using the Gene Ontology and Kyoto Encyclopedia of Genes and Genomes databases, pathway-gene networks were constructed using Cytoscape software.

Results

After integrated analysis of 4 GEO data sets (GSE48414, GSE51853, GSE63805 and GSE74190) and TCGA databases, miR-195 was identified as a potential clinical diagnostic marker. A total of 287 miR-195 target genes were screened, and 3 functional gene sets (GSE13485, GSE21379 and GSE29164) were enriched. GSE21379 was associated with the upregulation of CD4+ T cells in tumors, and the core genes were validated via the TIMER database. The CCDC88C expression level was significantly correlated with CD4+ T cell activation (partial.cor =0.437, P<0.001). Enrichment analysis revealed that CCDC88C was significantly enriched in the Wnt signaling pathway.

Conclusions

MiR-195, as a suppressor of lung adenocarcinoma, regulates CD4+ T cell activation via CCDC88C.

Wnt3a promotes radioresistance via autophagy in squamous cell carcinoma of the head and neck

The canonical Wnt/β‐catenin signalling pathway and autophagy play critical roles in cancer progression. However, the role of Wnt‐mediated autophagy in cancer radioresistance remains unclear. In this study, we found that irradiation activated the Wnt/β‐catenin and autophagic signalling pathways in squamous cell carcinoma of the head and neck (SCCHN). Wnt3a is a classical ligand that activated the Wnt/β‐catenin signalling pathway, induced autophagy and decreased the sensitivity of SCCHN to irradiation both in vitro and in vivo. Further mechanistic analysis revealed that Wnt3a promoted SCCHN radioresistance via protective autophagy. Finally, expression of the Wnt3a protein was elevated in both SCCHN tissues and patients' serum. Patients showing high expression of Wnt3a displayed a worse prognosis. Taken together, our study indicates that both the canonical Wnt and autophagic signalling pathways are valuable targets for sensitizing SCCHN to irradiation.

PITX2 enhances progression of lung adenocarcinoma by transcriptionally regulating WNT3A and activating Wnt/β-catenin signaling pathway

Background

The homeodomain transcription factor, PITX2 is associated with tumorigenesis of multiple cancers. In this research, we aimed to study the expression, function and mechanism of PITX2 in lung adenocarcinoma (LUAD).

Methods

The TCGA dataset was used to analyze the expression and clinical significance of PITX2 in LUAD. The expression of PITX2 in tumor samples and LUAD cell lines was examined by quantitative real-time PCR (qRT-PCR) and western blotting. Small interfering RNAs (siRNAs) were constructed to knockdown PITX2 and to determine the physiological function of PITX2 in vitro. Xenograft model was used to confirm the role of PITX2 in vivo.

Results

PITX2 was overexpressed in LUAD and patients with high level of PITX2 had a worse overall survival and an advanced clinical stage. Knockdown of PITX2 inhibited cell proliferation, migration and invasion of LUAD cells. Further study revealed that the oncogenic role of PITX2 was dependent on activating Wnt/β-catenin signaling pathway, especially by transcriptionally regulating the Wnt gene family member, WNT3A. Lastly, we identified miR-140-5p as a negative mediator of PITX2 by binding its 3′UTR and ectopic expression of miR-140-5p inhibited progression of LUAD cells via suppressing the expression of PITX2.

Conclusions

Up-regulation of PITX2 acts as an oncogene in LUAD by activating Wnt/β-catenin signaling pathway, suggesting that PITX2 may serve as a novel diagnostic and prognostic biomarker in LUAD.

Electronic supplementary material

The online version of this article (10.1186/s12935-019-0800-7) contains supplementary material, which is available to authorized users.

Wnt1 silences chemokine genes in dendritic cells and induces adaptive immune resistance in lung adenocarcinoma

Lung adenocarcinoma (LUAD)-derived Wnts increase cancer cell proliferative/stemness potential, but whether they impact the immune microenvironment is unknown. Here we show that LUAD cells use paracrine Wnt1 signaling to induce immune resistance. In TCGA, Wnt1 correlates strongly with tolerogenic genes. In another LUAD cohort, Wnt1 inversely associates with T cell abundance. Altering Wnt1 expression profoundly affects growth of murine lung adenocarcinomas and this is dependent on conventional dendritic cells (cDCs) and T cells. Mechanistically, Wnt1 leads to transcriptional silencing of CC/CXC chemokines in cDCs, T cell exclusion and cross-tolerance. Wnt-target genes are up-regulated in human intratumoral cDCs and decrease upon silencing Wnt1, accompanied by enhanced T cell cytotoxicity. siWnt1-nanoparticles given as single therapy or part of combinatorial immunotherapies act at both arms of the cancer-immune ecosystem to halt tumor growth. Collectively, our studies show that Wnt1 induces immunologically cold tumors through cDCs and highlight its immunotherapeutic targeting.

Viral hepatitis, inflammation, and cancer: A lesson for autoimmunity

In the present review, we analyzed the various overlapping and non-mutually exclusive mechanisms that intersect and form complex and highly flexible immunological networks allowing the defense against liver infections and tumors. Liver immunity results from the combination of the skills of systemic and local immune system(s) to sense and recognize pathogen or tumor antigens, to sensitize a wide range of innate and adaptive immune cells, and to clear the "invaders", through the establishment of a transient liver immunopathology state undergoing resolution/control of infections or tumors, and memory development. Then, a special emphasis is placed on discussing about the capacity of the immune system(s) to develop a state of chronic low-level immunopathology adapting through the intervention of simultaneous immunoregulatory mechanisms, when the liver is infected by highly mutable viruses (e.g., hepatitis B or C viruses [HBV or HCV]) capable to escape from the immune recognition. The establishment of chronic inflammation represents an advantage for the species survival, because it guarantees the long-term survival of human hosts despite the virus persistence. However, chronic inflammation, in the long run, can evolve towards severe consequences (decompensated cirrhosis and hepatocellular carcinoma) in some individuals, finding requiring the impelling need of discovering new therapeutic anti-viral and immunostimulatory agents addressed, in combination, to fight especially HBV that, in contrast to HCV, lacks antivirals capable to eradicate the virus. Finally, we discussed the concept proposing that the divergent immunoregulatory mechanisms that develop in persisting infections or tumors, on the one hand, and autoimmunity, on the other hand, are the mirror image of each other, whose understanding is also relevant for preparing novel immunotherapeutic approaches in autoimmune diseases.