Sulindac targets nuclear beta-catenin accumulation and Wnt signalling in adenomas of patients with familial adenomatous polyposis and in human colorectal cancer cell lines

Mutational Landscape and Precision Medicine in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is the fourth most common malignancy worldwide and exhibits a universal burden as the incidence of the disease continues to rise. In addition to curative-intent therapies such as liver resection and transplantation, locoregional and systemic therapy options also exist. However, existing treatments carry a dismal prognosis, often plagued with high recurrence and mortality. For this reason, understanding the tumor microenvironment and mutational pathophysiology has become the center of investigation for disease control. The use of precision medicine and genetic analysis can supplement current treatment modalities to promote individualized management of HCC. In the search for personalized medicine, tools such as next-generation sequencing have been used to identify unique tumor mutations and improve targeted therapies. Furthermore, investigations are underway for specific HCC biomarkers to augment the diagnosis of malignancy, the prediction of whether the tumor environment is amenable to available therapies, the surveillance of treatment response, the monitoring for disease recurrence, and even the identification of novel therapeutic opportunities. Understanding the mutational landscape and biomarkers of the disease is imperative for tailored management of the malignancy. In this review, we summarize the molecular targets of HCC and discuss the current role of precision medicine in the treatment of HCC.

Wnt Signaling in Brain Tumors: A Challenging Therapeutic Target

The involvement of Wnt signaling in normal tissue homeostasis and disease has been widely demonstrated over the last 20 years. In particular, dysregulation of Wnt pathway components has been suggested as a relevant hallmark of several neoplastic malignancies, playing a role in cancer onset, progression, and response to treatments. In this review, we summarize the current knowledge on the instructions provided by Wnt signaling during organogenesis and, particularly, brain development. Moreover, we recapitulate the most relevant mechanisms through which aberrant Wnt pathway activation may impact on brain tumorigenesis and brain tumor aggressiveness, with a particular focus on the mutual interdependency existing between Wnt signaling components and the brain tumor microenvironment. Finally, the latest anti-cancer therapeutic approaches employing the specific targeting of Wnt signaling are extensively reviewed and discussed. In conclusion, here we provide evidence that Wnt signaling, due to its pleiotropic involvement in several brain tumor features, may represent a relevant target in this context, although additional efforts will be needed to: (i) demonstrate the real clinical impact of Wnt inhibition in these tumors; (ii) overcome some still unsolved concerns about the potential systemic effects of such approaches; (iii) achieve efficient brain penetration.

Understanding the Wnt Signaling Pathway in Acute Myeloid Leukemia Stem Cells: A Feasible Key against Relapses

Wnt signaling is a highly conserved pathway in evolution which controls important processes such as cell proliferation, differentiation and migration, both in the embryo and in the adult. Dysregulation of this pathway can favor the development of different types of cancer, such as acute myeloid leukemia and other hematological malignancies. Overactivation of this pathway may promote the transformation of pre-leukemic stem cells into acute myeloid leukemia stem cells, as well as the maintenance of their quiescent state, which confers them with self-renewal and chemoresistance capacity, favoring relapse of the disease. Although this pathway participates in the regulation of normal hematopoiesis, its requirements seem to be greater in the leukemic stem cell population. In this review, we explore the possible therapeutic targeting of Wnt to eradicate the LSCs of AML.

Hereditary Colorectal Cancer Syndromes: Molecular Genetics and Precision Medicine

Colorectal cancer (CRC) is the third most commonly diagnosed cancer worldwide. Hereditary CRC syndromes account for approximately 5-10% of all CRC, with a lifetime risk of CRC that approaches 50-80% in the absence of endoscopic or surgical treatment. Hereditary CRC syndromes can be phenotypically divided into polyposis and non-polyposis syndrome, mainly according to the conditions of polyps. The typical representatives are familial adenomatous polyposis (FAP) and Lynch syndromes (LS), respectively. Over the past few decades, molecular genetics enhanced the discovery of cancer-predisposing genes and revolutionized the field of clinical oncology. Hereditary CRC syndromes have been a key part of this effort, with data showing that pathogenic variants are present in up to 10% of cases. Molecular phenotypes of tumors can not only help identify individuals with genetic susceptibility to CRC but also guide the precision prevention and treatment for the development of CRC. This review emphasizes the molecular basis and prevention strategies for hereditary CRC syndromes.

Inhibitory effect of selected Indian honey on colon cancer cell growth by inducing apoptosis and targeting the β-catenin/Wnt pathway

Colon cancer is the most prevalent cause of death from cancer across the globe. Although chemotherapy drugs are predominantly used, their toxicity always remains a cause of concern. As an alternative to synthetic drugs, natural compounds or nutraceuticals are comparatively less toxic. Honey is widely used across different cultures as an alternative form of medicine. It represents a prominent source of plant-phenolic compounds and there is demonstrable evidence of its anti-oxidant and anti-microbial activities. The aim of the present work was to investigate the anti-proliferative effect of some Indian honeys and analyze their mechanism of action in colon cancer. In order to establish the composition-activity relationship, we evaluated the bioactive components present in selected honey samples by GC-MS and HPLC analysis. Indian honey samples showed a significant inhibitory impact on cell growth by restricting cell proliferation, causing apoptosis, and restricting the cell cycle in the G₂/M phase specifically for colon cancer cells. The apoptotic activities, as imparted by the honey samples, were established by Annexin V/PI staining, real-time PCR, and immunoblot analyses. The treated cells showed increased expressions of p53 and caspases 3, 8, and 9, thus indicating the involvement of both extrinsic and intrinsic apoptotic pathways. The honey samples were also found to inhibit the β-catenin/Wnt pathway. In the next phase of the study, the efficacy of these honey samples was evaluated in colon carcinoma induced SD-rats. Overall, these findings demonstrated that selected Indian honeys could be established as effective nutraceuticals for the prevention as well as cure of colon cancer.

Wnt signaling in colorectal cancer: pathogenic role and therapeutic target

Background

The Wnt signaling pathway is a complex network of protein interactions that functions most commonly in embryonic development and cancer, but is also involved in normal physiological processes in adults. The canonical Wnt signaling pathway regulates cell pluripotency and determines the differentiation fate of cells during development. The canonical Wnt signaling pathway (also known as the Wnt/β-catenin signaling pathway) is a recognized driver of colon cancer and one of the most representative signaling pathways. As a functional effector molecule of Wnt signaling, the modification and degradation of β-catenin are key events in the Wnt signaling pathway and the development and progression of colon cancer. Therefore, the Wnt signaling pathway plays an important role in the pathogenesis of diseases, especially the pathogenesis of colorectal cancer (CRC).

Objective

Inhibit the Wnt signaling pathway to explore the therapeutic targets of colorectal cancer.

Methods

Based on studying the Wnt pathway, master the biochemical processes related to the Wnt pathway, and analyze the relevant targets when drugs or inhibitors act on the Wnt pathway, to clarify the medication ideas of drugs or inhibitors for the treatment of diseases, especially colorectal cancer.

Results

Wnt signaling pathways include: Wnt/β-catenin or canonical Wnt signaling pathway, planar cell polarity (Wnt-PCP) pathway and Wnt-Ca²⁺ signaling pathway. The Wnt signaling pathway is closely related to cancer cell proliferation, stemness, apoptosis, autophagy, metabolism, inflammation and immunization, microenvironment, resistance, ion channel, heterogeneity, EMT/migration/invasion/metastasis. Drugs/phytochemicals and molecular preparations for the Wnt pathway of CRC treatment have now been developed. Wnt inhibitors are also commonly used clinically for the treatment of CRC.

Conclusion

The development of drugs/phytochemicals and molecular inhibitors targeting the Wnt pathway can effectively treat colorectal cancer clinically.

β-Catenin signaling in hepatocellular carcinoma

Deregulated Wnt/β-catenin signaling is one of the main genetic alterations in human hepatocellular carcinoma (HCC). Comprehensive genomic analyses have revealed that gain-of-function mutation of CTNNB1, which encodes β-catenin, and loss-of-function mutation of AXIN1 occur in approximately 35% of human HCC samples. Human HCCs with activation of the Wnt/β-catenin pathway demonstrate unique gene expression patterns and pathological features. Activated Wnt/β-catenin synergizes with multiple signaling cascades to drive HCC formation, and it functions through its downstream effectors. Therefore, strategies targeting Wnt/β-catenin have been pursued as possible therapeutics against HCC. Here, we review the genetic alterations and oncogenic roles of aberrant Wnt/β-catenin signaling during hepatocarcinogenesis. In addition, we discuss the implication of this pathway in HCC diagnosis, classification, and personalized treatment.

Combined Treatment with a WNT Inhibitor and the NSAID Sulindac Reduces Colon Adenoma Burden in Mice with Truncated APC

Adenomatous polyposis coli (APC) truncations occur in many colorectal cancers and are often associated with immune infiltration. The aim of this study was to determine whether a combination of Wnt inhibition with anti-inflammatory (sulindac) and/or proapototic (ABT263) drugs can reduce colon adenomas. Apc ^min/+ and doublecortin-like kinase 1 (Dclk1)^Cre/+ ;Apc ^fl/fl mice were exposed to dextran sulphate sodium (DSS) in their drinking water to promote the formation of colon adenomas. Mice were then treated with either a Wnt-signaling antagonist pyrvinium pamoate (PP), an anti-inflammatory agent sulindac or proapoptotic compound ABT263 or a combination of PP+ABT263, or PP+sulindac. Colon adenoma frequency, size, and T-cell abundance were measured. DSS treatment resulted in significant increases in colon adenoma number (P < 0.001, n > 5) and burden in Apc ^min/+ (P < 0.01, n > 5) and Dclk1 ^Cre/+ ;Apc ^fl/fl (P < 0.02, n > 5) mice. There was no effect on adenomas following treatment with PP in combination with ABT263. Adenoma number and burden were reduced with PP+sulindac treatment in Dclk1 ^Cre/+;Apc ^fl/fl mice (P < 0.01, n > 17) and in Apc ^min/+ mice (P < 0.001, n > 7) treated with sulindac or PP+sulindac with no detectable toxicity. PP treatment of Apc ^min/+ mice increased the frequency of CD3⁺ cells in the adenomas. The combination of Wnt pathway inhibition with sulindac was more effective in Dclk1 ^Cre/+;Apc ^fl/fl mice and provides an opportunity for killing Apc-mutant colon adenoma cells, indicating a strategy for both colorectal cancer prevention and potential new treatments for patients with advanced colorectal cancer. Outcomes from the results of this study may be translatable to the clinic for management of FAP and other patients with a high risk of developing colorectal cancer.

Significance

Colorectal cancer is one of the most common cancers worldwide with limited therapeutic options. APC and other Wnt signaling mutations occur in the majority of colorectal cancers but there are currently no Wnt inhibitors in the clinic. The combination of Wnt pathway inhibition with sulindac provides an opportunity for killing Apc-mutant colon adenoma cells and suggests a strategy for colorectal cancer prevention and new treatments for patients with advanced colorectal cancer.

NSAIDs and Cancer Resolution: New Paradigms beyond Cyclooxygenase

Acute inflammation or resolved inflammation is an adaptive host defense mechanism and is self-limiting, which returns the body to a state of homeostasis. However, unresolved, uncontrolled, or chronic inflammation may lead to various maladies, including cancer. Important evidence that links inflammation and cancer is that nonsteroidal anti-inflammatory drugs (NSAIDs), such as aspirin, reduce the risk and mortality from many cancers. The fact that NSAIDs inhibit the eicosanoid pathway prompted mechanistic drug developmental work focusing on cyclooxygenase (COX) and its products. The increased prostaglandin E2 levels and the overexpression of COX-2 in the colon and many other cancers provided the rationale for clinical trials with COX-2 inhibitors for cancer prevention or treatment. However, NSAIDs do not require the presence of COX-2 to prevent cancer. In this review, we highlight the effects of NSAIDs and selective COX-2 inhibitors (COXIBs) on targets beyond COX-2 that have shown to be important against many cancers. Finally, we hone in on specialized pro-resolving mediators (SPMs) that are biosynthesized locally and, in a time, -dependent manner to promote the resolution of inflammation and subsequent tissue healing. Different classes of SPMs are reviewed, highlighting aspirin's potential in triggering the production of these resolution-promoting mediators (resolvins, lipoxins, protectins, and maresins), which show promise in inhibiting cancer growth and metastasis.

The Wnt signaling pathway in tumorigenesis, pharmacological targets, and drug development for cancer therapy

Wnt signaling was initially recognized to be vital for tissue development and homeostasis maintenance. Further studies revealed that this pathway is also important for tumorigenesis and progression. Abnormal expression of signaling components through gene mutation or epigenetic regulation is closely associated with tumor progression and poor prognosis in several tissues. Additionally, Wnt signaling also influences the tumor microenvironment and immune response. Some strategies and drugs have been proposed to target this pathway, such as blocking receptors/ligands, targeting intracellular molecules, beta-catenin/TCF4 complex and its downstream target genes, or tumor microenvironment and immune response. Here we discuss the roles of these components in Wnt signaling pathway in tumorigenesis and cancer progression, the underlying mechanisms that is responsible for the activation of Wnt signaling, and a series of drugs targeting the Wnt pathway provide multiple therapeutic values. Although some of these drugs exhibit exciting anti-cancer effect, clinical trials and systematic evaluation should be strictly performed along with multiple-omics technology.

Cyclin G2, a novel target of sulindac to inhibit cell cycle progression in colorectal cancer

Sulindac has shown significant clinical benefit in preventing colorectal cancer progression, but its mechanism of action has not been fully elucidated. We have found that sulindac sulfide (SS) is able to inhibit cell cycle progression in human colorectal cancer cells, particularly through G1 arrest. To understand the underlying mechanisms of sulindac inhibitory activity, we have demonstrated that Cyclin G2 up-regulation upon SS treatment can substantially delay cell cycle progression by enhancing the transcriptional activity of FOXO3a in human colorectal tumor cells. MiR-182, an oncogenic microRNA known to inhibit FOXO3a gene expression, is also involved in the suppressive effect of SS on cell cycle progression. This process begins with the down-regulation of miR-182, followed by the enhancement of FOXO3a transcriptional activity and the up-regulation of Cyclin G2. To further determine the clinical utility of this axis, we analyzed the expression of miR-182/FOXO3a/Cyclin G2 in human colorectal tumor samples. Our results show not only that there are significant differences in miR-182/FOXO3a/Cyclin G2 between tumors and normal tissues, but also that the synergetic effect of miR-182 and FOXO3a is associated with predicting tumor progression. Our study demonstrates a novel mechanistic axis consisting of miR-182/FOXO3a/Cyclin G2 that mediates sulindac inhibition of cell cycle progression.

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.

Fundamental insights into the interaction between telomerase/TERT and intracellular signaling pathways

Telomerase activity is critical for cancer cells to provide unrestricted proliferation and cellular immortality through maintaining telomeres. Telomerase enzymatic activity is regulatable at the level of DNA, mRNA, post translational modifications, cellular transport and enzyme assembly. More recent studies confirm the interaction of the telomerase with various intracellular signaling pathways including PI3K/AKT/mTOR, NF-κB and Wnt/β-catenin which mainly participating in inflammation, epithelial to mesenchymal transition (EMT) and tumor cell invasion and metastasis. Furthermore, hTERT protein has been detected in non-nuclear sites such as the mitochondria and cytoplasm in cells. Mitochondrial TERT indicates various non-telomere-related functions such as decreasing reactive oxygen species (ROS) generation, boosting the respiration rate, protecting mtDNA by direct binding, interacting with mitochondrial tRNAs and increasing mitochondrial membrane potential which can lead to higher chemoresistance rate in cancer cells during therapies. Understanding the molecular mechanisms of the TERT function and depended interactions in tumor cells can suggest novel therapeutic approaches. Hence, in this review we will explain the telomerase activity regulation in translational and post translational levels besides the established correlations with various cell signaling pathways with possible pathways for therapeutic targeting.

CTNNB1 mutation suppresses infiltration of immune cells in hepatocellular carcinoma through miRNA-mediated regulation of chemokine expression

Mutations in the CTNNB1 gene in hepatocellular carcinoma (HCC) are related to immune exclusion, and HCC patients with CTNNB1 mutations tend to be primarily resistant to anti-PD1 therapy. However, systemic evaluation of immune cell infiltration in HCC with mutant CTNNB1 is lacking, and the mechanism of immune exclusion resulting from CTNNB1 mutations remains unclear. Based on CTNNB1 mutation status in HCC, we investigated RNA and miRNA expression and infiltration of immune cells. Data downloaded from TCGA showed that HCC with CTNNB1 mutation had an increased expression of CTNNB1. HCC with CTNNB1 mutation showed a reduction in infiltration score as well as in abundance of certain kinds of immune cells, including CD4 naïve T cells, CD4+ T cells, Tex cells, Th2 cells, Tfh cells, B cells, macrophages, and NK cells. Furthermore, there were 13 chemokines downregulated among all the 14 differentially expressed chemokines (DE-CKs) in CTNNB1 mutants compared to those in the wild type. A positive correlation was found between the expression of DE-CKs and infiltration score, as well as infiltration level of 6 types of immune cells, namely B cells, CD8+ cells, CD4+ cells, macrophages, neutrophils, and dendritic cells. Additionally, 302 differentially expressed immune-related genes (DE-IRGs) were involved mainly in the human immune response and cytokine-cytokine receptor interaction. The target DE-IRGs of differentially expressed miRNAs (DE-miRNAs) were identified and used to construct a network with DE-miRNAs and DE-CKs. Overall, CTNNB1 mutation in HCC led to a decrease in chemokine expression and subsequent suppression of immune cell infiltration partly through regulating specific miRNA-IRG-CK axes, pointing to a potential combination of interference of Wnt/β-catenin signaling with immunotherapy in HCC with CTNNB1 mutation.

Sulindac plus a phospholipid is effective for polyp reduction and safer than sulindac alone in a mouse model of colorectal cancer development

Background

Non-steroidal anti-inflammatory drugs (NSAIDs) such as aspirin and sulindac are effective for colorectal cancer prevention in humans and some animal models, but concerns over gastro-intestinal (GI) ulceration and bleeding limit their potential for chemopreventive use in broader populations. Recently, the combination of aspirin with a phospholipid, packaged as PL-ASA, was shown to reduce GI toxicity in a small clinical trial. However, these studies were done for relatively short periods of time. Since prolonged, regular use is needed for chemopreventive benefit, it is important to know whether GI safety is maintained over longer use periods and whether cancer prevention efficacy is preserved when an NSAID is combined with a phospholipid.

Methods

As a first step to answering these questions, we treated seven to eight-week-old, male and female C57B/6 Apc^min/+ mice with the NSAID sulindac, with and without phosphatidylcholine (PC) for 3-weeks. At the end of the treatment period, we evaluated polyp burden, gastric toxicity, urinary prostaglandins (as a marker of sulindac target engagement), and blood chemistries.

Results

Both sulindac and sulindac-PC treatments resulted in significantly reduced polyp burden, and decreased urinary prostaglandins, but sulindac-PC treatment also resulted in the reduction of gastric lesions compared to sulindac alone.

Conclusions

Together these data provide pre-clinical support for combining NSAIDs with a phospholipid, such as phosphatidylcholine to reduce GI toxicity while maintaining chemopreventive efficacy.

Wnt Signaling in Leukemia and Its Bone Marrow Microenvironment

Leukemia is an aggressive hematologic neoplastic disease. Therapy-resistant leukemic stem cells (LSCs) may contribute to the relapse of the disease. LSCs are thought to be protected in the leukemia microenvironment, mainly consisting of mesenchymal stem/stromal cells (MSC), endothelial cells, and osteoblasts. Canonical and noncanonical Wnt pathways play a critical role in the maintenance of normal hematopoietic stem cells (HSC) and LSCs. In this review, we summarize recent findings on the role of Wnt signaling in leukemia and its microenvironment and provide information on the currently available strategies for targeting Wnt signaling.

Recent Advances in Desmoid Tumor Therapy

The desmoid tumor is a locally aggressive proliferative disease within the family of soft-tissue sarcomas. Despite its relatively good prognosis, the clinical management of desmoid tumors requires constant multidisciplinary evaluation due to its highly variable clinical behavior. Recently, active surveillance has being regarded as the appropriate strategy at diagnosis, as indolent persistence or spontaneous regressions are not uncommon. Here, we review the most recent advances in desmoid tumor therapy, including low-dose chemotherapy and treatment with tyrosine kinase inhibitors. We also explore the recent improvements in our knowledge of the molecular biology of this disease, which are leading to clinical trials with targeted agents.

DJ-1 promotes epithelial-to-mesenchymal transition via enhancing FGF9 expression in colorectal cancer

Tumor metastasis is the main contributor to high recurrence and mortality in colorectal cancer (CRC). In a previous study, we found that DJ-1 plays an important role in CRC metastasis, and is the main target in Ciclopirox olamine (CPX)-treated CRC. However, the mechanism underlying DJ-1-induced CRC metastasis remains elusive. In the present study, our results showed that DJ-1 could activate Wnt signaling resulting in enhanced invasive potential and epithelial-to-mesenchymal transition (EMT) in CRC cells. RNA-seq and bioinformatics analysis reveals that the DJ-1/Wnt signaling pathway may promote CRC cells' EMT by regulating fibroblast growth factor 9 (FGF9) expression. Molecular validation showed that expression of FGF9 was upregulated by the DJ-1/Wnt signaling pathway and decreasing FGF9-expression impeded DJ-1-induced CRC invasive ability and EMT, suggesting that FGF9 is involved in DJ-1-enhanced CRC metastasis. In addition, we show that FGF9 was overexpressed in CRC human specimens and was significantly associated with tumor differentiation. High FGF9 expression was correlated with worse overall survival, and a correlation exhibited between FGF9 and EMT markers (E-cadherin and Vimentin) in CRC samples. Together, our results determined that FGF9 was involved in DJ-1-induced invasion and EMT in CRC cells, and may represent a promising therapeutic candidate for CRC anti-metastatic strategies.

Cyclooxygenases Inhibitors Efficiently Induce Cardiomyogenesis in Human Pluripotent Stem Cells

Application of human pluripotent stem cell-derived cardiomyocytes (hPSC-CMs) is limited by the challenges in their efficient differentiation. Recently, the Wingless (Wnt) signaling pathway has emerged as the key regulator of cardiomyogenesis. In this study, we evaluated the effects of cyclooxygenase inhibitors on cardiac differentiation of hPSCs. Cardiac differentiation was performed by adherent monolayer based method using 4 hPSC lines (HES3, H9, IMR90, and ES4SKIN). The efficiency of cardiac differentiation was evaluated by flow cytometry and RT-qPCR. Generated hPSC-CMs were characterised using immunocytochemistry, electrophysiology, electron microscopy, and calcium transient measurements. Our data show that the COX inhibitors Sulindac and Diclofenac in combination with CHIR99021 (GSK-3 inhibitor) efficiently induce cardiac differentiation of hPSCs. In addition, inhibition of COX using siRNAs targeted towards COX-1 and/or COX-2 showed that inhibition of COX-2 alone or COX-1 and COX-2 in combination induce cardiomyogenesis in hPSCs within 12 days. Using IMR90-Wnt reporter line, we showed that inhibition of COX-2 led to downregulation of Wnt signalling activity in hPSCs. In conclusion, this study demonstrates that COX inhibition efficiently induced cardiogenesis via modulation of COX and Wnt pathway and the generated cardiomyocytes express cardiac-specific structural markers as well as exhibit typical calcium transients and action potentials. These cardiomyocytes also responded to cardiotoxicants and can be relevant as an in vitro cardiotoxicity screening model.

Molecular Signaling Pathways and Therapeutic Targets in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is a complex biological process and is often diagnosed at advanced stages with no effective treatment options. With advances in tumor biology and molecular genetic profiling, several different signaling pathways and molecular mechanisms have been identified as responsible for initiating and promoting HCC. Targeting these critical pathways, which include the receptor tyrosine kinase pathways, the Ras mitogen-activated protein kinase (Ras/Raf/MAPK), the phosphatidylinositol 3-kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR), the Wnt/β-catenin signaling pathway, the ubiquitin/proteasome degradation and the hedgehog signaling pathway has led to the identification of novel therapeutics for HCC treatment. In this review, we elaborated on our current understanding of the signaling pathways involved in the development and initiation of HCC and anticipate the potential targets for therapeutic drug development.

Targeting the Versatile Wnt/β-Catenin Pathway in Cancer Biology and Therapeutics: From Concept to Actionable Strategy

This expert review offers a critical synthesis of the latest insights and approaches at targeting the Wnt/β-catenin pathway in various cancers such as colorectal cancer, melanoma, leukemia, and breast and lung cancers. Notably, from organogenesis to cancer, the Wnt/β-catenin signaling displays varied and highly versatile biological functions in animals, with virtually all tissues requiring the Wnt/β-catenin signaling in one way or the other. Aberrant expression of the members of the Wnt/β-catenin has been implicated in many pathological conditions, particularly in human cancers. Mutations in the Wnt/β-catenin pathway genes have been noted in diverse cancers. Biochemical and genetic data support the idea that inhibition of Wnt/β-catenin signaling is beneficial in cancer therapeutics. The interaction of this important pathway with other signaling systems is also noteworthy, but remains as an area for further research and discovery. In addition, formation of different complexes by components of the Wnt/β-catenin pathway and the precise roles of these complexes in the cytoplasmic milieu are yet to be fully elucidated. This article highlights the latest medical technologies in imaging, single-cell omics, use of artificial intelligence (e.g., machine learning techniques), genome sequencing, quantum computing, molecular docking, and computational softwares in modeling interactions between molecules and predicting protein-protein and compound-protein interactions pertinent to the biology and therapeutic value of the Wnt/β-catenin signaling pathway. We discuss these emerging technologies in relationship to what is currently needed to move from concept to actionable strategies in translating the Wnt/β-catenin laboratory discoveries to Wnt-targeted cancer therapies and diagnostics in the clinic.

Targeting the Canonical WNT/β-Catenin Pathway in Cancer Treatment Using Non-Steroidal Anti-Inflammatory Drugs

Chronic inflammation and oxidative stress are common and co-substantial pathological processes accompanying and contributing to cancers. Numerous epidemiological studies have indicated that non-steroidal anti-inflammatory drugs (NSAIDs) could have a positive effect on both the prevention of cancer and tumor therapy. Numerous hypotheses have postulated that NSAIDs could slow tumor growth by acting on both chronic inflammation and oxidative stress. This review takes a closer look at these hypotheses. In the cancer process, one of the major signaling pathways involved is the WNT/β-catenin pathway, which appears to be upregulated. This pathway is closely associated with both chronic inflammation and oxidative stress in cancers. The administration of NSAIDs has been observed to help in the downregulation of the WNT/β-catenin pathway and thus in the control of tumor growth. NSAIDs act as PPARγ agonists. The WNT/β-catenin pathway and PPARγ act in opposing manners. PPARγ agonists can promote cell cycle arrest, cell differentiation, and apoptosis, and can reduce inflammation, oxidative stress, proliferation, invasion, and cell migration. In parallel, the dysregulation of circadian rhythms (CRs) contributes to cancer development through the upregulation of the canonical WNT/β-catenin pathway. By stimulating PPARγ expression, NSAIDs can control CRs through the regulation of many key circadian genes. The administration of NSAIDs in cancer treatment would thus appear to be an interesting therapeutic strategy, which acts through their role in regulating WNT/β-catenin pathway and PPARγ activity levels.

Therapeutic potential of targeting the Wnt/β-catenin pathway in the treatment of pancreatic cancer

The Wnt/β-catenin pathway is an important, dysregulated pathway in several tumor types, including pancreatic ductal adenocarcinoma. Although the activation of this pathway is an important component of normal development, its aberrant activation resulting from activating or inactivating mutations in the CTNNB1 gene locus, or in the negative regulators AXIN and APC involving stabilization of β-catenin, and activation of target genes leads to a more aggressive phenotype, suggesting its potential value as a therapeutic target in the treatment of pancreatic ductal adenocarcinoma. A number of small molecule and biologic agents have now been developed for targeting this pathway. This review summarizes the current knowledge about the therapeutic potential of targeting the Wnt pathway with particular emphasis on preclinical/clinical studies in the treatment of pancreatic ductal adenocarcinoma.

Recent Development of Wnt Signaling Pathway Inhibitors for Cancer Therapeutics

PURPOSE OF REVIEW

Review current understanding of both canonical and non-canonical Wnt signaling in cancer and provide updated knowledge in current clinical trials of Wnt signaling drugs.

RECENT FINDINGS

Important roles of both canonical and non-canonical Wnt signaling in cancer have been increasingly recognized. Recent clinical trials of several Wnt-signaling drugs have showed promising outcomes. In addition, some drugs that were originally approved for the treatment of other diseases have been recently found to block Wnt signaling, highlighting their potential to treat Wnt-dependent cancer. Dysfunction of Wnt signaling is implicated in cancer, and targeting Wnt signaling represents a useful approach to treat cancer. Current clinical trials of Wnt signaling drugs have showed promising outcomes, and repurposing the previously approved drugs for other diseases to treat Wnt-dependent cancer requires further studies.

DJ-1 promotes colorectal cancer progression through activating PLAGL2/Wnt/BMP4 axis

Metastasis remains a big barrier for the clinical treatment of colorectal cancer (CRC). Our previous proteomics analysis identified DJ-1 as a potential metastasis biomarker of CRC. In this study, we found that DJ-1 was upregulated in CRC. The levels of DJ-1 were closely correlated with the depths of invasion and predicted patient outcome. Enforced expression of DJ-1 could enhance CRC proliferation and metastasis in vitro and in vivo by stimulating Wnt-β-catenin signaling. Specifically, DJ-1-induced β-catenin nuclear translocation stimulated TCF transcription activity, which promoted BMP4 expression for CRC cell migration and invasion, and elevated CCND1 expression for CRC cell proliferation, respectively. Furthermore, DJ-1-induced Wnt signaling activation was dependent on PLAGL2 expression. In conclusion, our study demonstrates that DJ-1 can promote CRC metastasis by activating PLAGL2-Wnt-BMP4 axis, suggesting novel therapeutic opportunities for postoperative adjuvant therapy in CRC patients.

IL-1β Stimulates Brain-Derived Neurotrophic Factor Production in Eutopic Endometriosis Stromal Cell Cultures: A Model for Cytokine Regulation of Neuroangiogenesis

Endometriosis implants are comprised of glandular and stromal elements, macrophages, nerves, and blood vessels and are commonly accompanied by pelvic pain. We propose that activated macrophages are recruited to and infiltrate nascent lesions, where they secrete proinflammatory cytokines, promoting the production of chemokines, neurotrophins, and angiogenic growth factors that sustain an inflammatory microenvironment. Immunohistochemical evaluation of endometriosis lesions reveals in situ colocalization of concentrated macrophages, brain-derived neurotrophic factor (BDNF), and nerve fibers. These observations were coupled with biochemical analyses of primary eutopic endometriosis stromal cell (EESC) cultures, which allowed defining potential pathways leading to the neuroangiogenic phenotype of these lesions. Our findings indicate that IL-1β potently (EC₅₀ = 7 ± 2 ng/mL) stimulates production of EESC BDNF at the mRNA and protein levels in an IL-1 receptor-dependent fashion. Selective kinase inhibitors demonstrate that this IL-1β effect is mediated by c-Jun N-terminal kinase (JNK), NF-κB, and mechanistic target of rapamycin signal transduction pathways. IL-1β regulation of regulated on activation normal T cell expressed and secreted (RANTES), a prominent EESC chemokine, also relies on JNK and NF-κB. An important clinical implication of the study is that interference with BDNF and RANTES production, by selectively targeting the JNK and NF-κB cascades, may offer a tractable therapeutic strategy to mitigate the pain and inflammation associated with endometriosis.

Effects of Nonsteroidal Anti-Inflammatory Drugs at the Molecular Level

Nonsteroidal anti-inflammatory drugs (NSAIDs) are commonly used for their anti-inflammatory, analgesic, and antipyretic effects. NSAIDs generally work by blocking the production of prostaglandins (PGs) through the inhibition of two cyclooxygenase enzymes. PGs are key factors in many cellular processes, such as gastrointestinal cytoprotection, hemostasis and thrombosis, inflammation, renal hemodynamics, turnover of cartilage, and angiogenesis. Interest has grown in the various effects of NSAIDs during the last decade. Epidemiological studies have revealed the reduced risk of several cancer types and neurodegenerative diseases by prolonged use of NSAIDs. Recent advances in the understanding of the cellular and molecular mechanisms of NSAIDs will accelerate the processes of discovery and clinical implementation. This review summarizes the molecular mechanisms of NSAIDs on the body systems.

Next-Generation Sequencing of Circulating Tumor DNA Reveals Frequent Alterations in Advanced Hepatocellular Carcinoma

This article reports unique aspects of the management of hepatocellular carcinoma. The study aimed to determine if next‐generation sequencing of blood‐derived circulating tumor DNA from patients with hepatocellular carcinoma could identify actionable somatic molecular alterations. Illustrative examples of treated patients and of in silico molecular dynamic simulation to reveal genomic variant function are included.

Background.

Because imaging has a high sensitivity to diagnose hepatocellular carcinoma (HCC) and tissue biopsies carry risks such as bleeding, the latter are often not performed in HCC. Blood‐derived circulating tumor DNA (ctDNA) analysis can identify somatic alterations, but its utility has not been characterized in HCC.

Materials and Methods.

We evaluated 14 patients with advanced HCC (digital ctDNA sequencing [68 genes]). Mutant relative to wild‐type allele fraction was calculated.

Results.

All patients (100%) had somatic alterations (median = 3 alterations/patient [range, 1–8]); median mutant allele fraction, 0.29% (range, 0.1%–37.77%). Mutations were identified in several genes: TP53 (57% of patients), CTNNB1 (29%), PTEN (7%), CDKN2A (7%), ARID1A (7%), and MET (7%); amplifications, in CDK6 (14%), EGFR (14%), MYC (14%), BRAF (7%), RAF1 (7%), FGFR1 (7%), CCNE1 (7%), PIK3CA (7%), and ERBB2/HER2 (7%). Eleven patients (79%) had ≥1 theoretically actionable alteration. No two patients had identical genomic portfolios, suggesting the need for customized treatment. A patient with a CDKN2A‐inactivating and a CTNNB1‐activating mutation received matched treatment: palbociclib (CDK4/6 inhibitor) and celecoxib (COX‐2/Wnt inhibitor); des‐gamma‐carboxy prothrombin level decreased by 84% at 2 months (1,410 to 242 ng/mL [normal: ≤7.4 ng/mL]; alpha fetoprotein [AFP] low at baseline). A patient with a PTEN‐inactivating and a MET‐activating mutation (an effect suggested by in silico molecular dynamic simulations) received sirolimus (mechanistic target of rapamycin inhibitor) and cabozantinib (MET inhibitor); AFP declined by 63% (8,320 to 3,045 ng/mL [normal: 0–15 ng/mL]).

Conclusion.

ctDNA derived from noninvasive blood tests can provide exploitable genomic profiles in patients with HCC.

Implications for Practice.

This study reports that blood‐derived circulating tumor DNA can provide therapeutically exploitable genomic profiles in hepatocellular cancer, a malignancy that is known to be difficult to biopsy.

Reciprocal control of lncRNA-BCAT1 and β-catenin pathway reveals lncRNA-BCAT1 long non-coding RNA acts as a tumor suppressor in colorectal cancer

β-catenin plays a major role in tumor development and progression. The present study found that β-catenin was upregulated in 30 samples of colorectal cancer (CRC) tissue as compared to adjacent non-tumor tissues. Analysis of long non-coding RNA (lncRNA) expression profiles using the GSE18560 and GSE44097 datasets, which were generated via the Affymetrix plus 2.0 microarray platform and downloaded from the GEO database, revealed 20 differentially expressed lncRNAs following β-catenin knockdown. We focused on AK091631, a novel lncRNA, which we named lncRNA-β-catenin associated transcript 1 (LncRNA-BCAT1). lncRNA-BCAT1 expression was decreased in CRC tissues, and was negatively associated with β-catenin in both CRC tissues and cell lines. lncRNA-BCAT1 overexpression suppressed CRC cell growth and invasion by downregulating cyclin D1, c-Myc, and MMP-2. These results suggest that lncRNA-BCAT1 overexpression inhibits CRC cell growth and invasion via Wnt/β-catenin pathway blockade, and that lncRNA-BCAT1 is repressed by Wnt/β-catenin signaling. This evidence suggests that lncRNA-BCAT1 is a tumor suppressor and that lncRNA-BCAT1 may be an effective prognostic biomarker in CRC.

Longitudinal analysis of colon crypt stem cell dynamics in sulindac treated Familial Adenomatous Polyposis patients

The non-steroidal anti-inflammatory drug sulindac decreases size and number of adenomas after 4-6 months of treatment for familial adenomatous polyposis (FAP) patients. However, the underlying mechanism remains unknown. As stem cells are thought to be the tumor precursor cells, visualizing their behavior is crucial for monitoring tumor progression. Increased tag diversity in inactive genes is indicative of a protracted clonal evolution and consequently, increased risk for tumor formation. Therefore, the effect of sulindac on stem cell dynamics was studied. Normal appearing single crypts were laser microdissected in placebo- and sulindac- treated FAP patient tissue after which the methylation patterns were visualized by Next Generation Sequencing. A significant difference in tag diversity over time was found in the sulindac group compared to the placebo group (*p = 0.018), indicative of a shortened clonal evolution treated sulindac. The rate of change in tag diversity over time was correlated with polyp number change over time. No significant difference over time was observed in the percent methylation when comparing placebo vs sulindac. In conclusion, daily sulindac administration in FAP patients significantly altered colorectal stem cell dynamics, which might explain the chemopreventive action of this drug indicating that tag diversity may be used as a predictive biomarker.

Effective treatment of aggressive fibromatosis with celecoxib guided by genetic testing

Aggressive fibromatosis (AF) or desmoid tumors is an aggressive fibroblastic proliferation which is locally invasive but can not metastasize. The treatment of AF is challenging. Surgery was the main treatment modality for AF in the past, other strategies including radiotherapy, systemic therapies and wait-and-see policy. The use of non-steroidal anti-inflammatory drugs (NSAIDs) and targeted therapies has demonstrated good results. In the case report, a 39-year-old man presented with progressive chest wall pain. Computed tomography (CT) showed an approximately 46× 13 mm soft-tissue mass between the inside of the fifth and sixth rib on the right side. The entire mass was excised and an AF was confirmed based on histopathology. Four months after surgery, magnetic resonance imaging (MRI) showed a soft-tissue mass in surgical areas and biopsy confirmed local recurrence. Therefore, Tomotherapy was administered. However, two months later, an (18)F-fluorodeoxyglucose (FDG) Positron Emission Tomography combined with CT (PET-CT) revealed the presence of an FDG-avid mass in the area of local recurrence. Genetic testing reported the presence of a p.T41A mutations on the CTNNB1 gene, which predicted that he is sensitive to the COX-2 inhibitor celecoxib. The tumor regressed rapidly after the application of celecoxib. Within the 20-month follow-up period, the patient showed remarkable regression without any signs and symptoms. Our case report provides further evidence for the efficacy of celecoxib in AF with CTNNB1 gene mutations. To our knowledge, this is the first report of AF treated with celecoxib under the guidance of the genetic testing. However, further studies are required.

The biology of Hepatocellular carcinoma: implications for genomic and immune therapies

Hepatocellular carcinoma (HCC), the most common type of primary liver cancer, is a leading cause of cancer-related death worldwide. It is highly refractory to most systemic therapies. Recently, significant progress has been made in uncovering genomic alterations in HCC, including potentially targetable aberrations. The most common molecular anomalies in this malignancy are mutations in the TERT promoter, TP53, CTNNB1, AXIN1, ARID1A, CDKN2A and CCND1 genes. PTEN loss at the protein level is also frequent. Genomic portfolios stratify by risk factors as follows: (i) CTNNB1 with alcoholic cirrhosis; and (ii) TP53 with hepatitis B virus-induced cirrhosis. Activating mutations in CTNNB1 and inactivating mutations in AXIN1 both activate WNT signaling. Alterations in this pathway, as well as in TP53 and the cell cycle machinery, and in the PI3K/Akt/mTor axis (the latter activated in the presence of PTEN loss), as well as aberrant angiogenesis and epigenetic anomalies, appear to be major events in HCC. Many of these abnormalities may be pharmacologically tractable. Immunotherapy with checkpoint inhibitors is also emerging as an important treatment option. Indeed, 82% of patients express PD-L1 (immunohistochemistry) and response rates to anti-PD-1 treatment are about 19%, and include about 5% complete remissions as well as durable benefit in some patients. Biomarker-matched trials are still limited in this disease, and many of the genomic alterations in HCC remain challenging to target. Future studies may require combination regimens that include both immunotherapies and molecularly matched targeted treatments.

Synthesis and preliminary assessment of the anticancer and Wnt/β-catenin inhibitory activity of small amide libraries of fenamates and profens

As part of an ongoing program to study the anticancer activity of non-steroidal anti-inflammatory drugs (NSAIDs) through generating diversity libraries of multiple NSAID scaffolds, we synthesized a series of NSAID amide derivatives and screened these sets against three cancer cell lines (prostate, colon and breast) and Wnt/β-catenin signaling. The evaluated amide analog libraries show significant anticancer activity/cell proliferation inhibition, and specific members of the sets show inhibition of Wnt/β-catenin signaling.

Opposing roles of ICAT and Wnt/β-catenin signaling in NSC67657-induced monocytic differentiation

NSC67657 is a new steroid drug that induces monocytic differentiation of acute myeloid leukemia cells. Here, we demonstrate that NSC67657 has opposing effects on expression of downstream targets of inhibitor of β-catenin and TCF (ICAT) and Wnt signaling in HL60 cells. ICAT binds to β-catenin, and this interaction is further increased in NSC67657-differentiated cells. ICAT overexpression decreases expression of Wnt downstream targets and increases sensitivity of HL60 cells to NSC67657, while ICAT silencing increases Wnt signaling and delays the NSC67657-induced cell differentiation. In addition, pharmacological inhibition of Wnt/β-catenin signaling increases the NSC67657-induced cell differentiation, while activation of Wnt/β-catenin signaling inhibits the differentiation, indicating Wnt/β-catenin signaling inhibits NSC67657-induced monocytic differentiation of HL60 cells. Our data demonstrate the opposing roles of ICAT and Wnt signaling in the NSC67657-induced monocytic differentiation, and suggest that ICAT and Wnt signaling may serve as therapeutic targets for leukemia chemotherapy.

Binding of canonical Wnt ligands to their receptor complexes occurs in ordered plasma membrane environments

While the cytosolic events of Wnt/β‐catenin signaling (canonical Wnt signaling) pathway have been widely studied, only little is known about the molecular mechanisms involved in Wnt binding to its receptors at the plasma membrane. Here, we reveal the influence of the immediate plasma membrane environment on the canonical Wnt–receptor interaction. While the receptors are distributed both in ordered and disordered environments, Wnt binding to its receptors selectively occurs in more ordered membrane environments which appear to cointernalize with the Wnt‐receptor complex. Moreover, Wnt/β‐catenin signaling is significantly reduced when the membrane order is disturbed by specific inhibitors of certain lipids that prefer to localize at the ordered environments. Similarly, a reduction in Wnt signaling activity is observed in Niemann–Pick Type C disease cells where trafficking of ordered membrane lipid components to the plasma membrane is genetically impaired. We thus conclude that ordered plasma membrane environments are essential for binding of canonical Wnts to their receptor complexes and downstream signaling activity.

The repressive effect of miR-148a on Wnt/β-catenin signaling involved in Glabridin-induced anti-angiogenesis in human breast cancer cells

Background

Glabridin (GLA), a major component extracted from licorice root, has anti-inflammatory and antioxidant activities, but few studies report its mechanism of inhibition of angiogenesis. This study was an extension of our previous work, which demonstrated that GLA suppressed angiogenesis in human breast cancer (MDA-MB-231 and Hs-578T) cells. Breast cancer is one of the most common malignant diseases in females worldwide, and the major cause of mortality is metastasis that is primarily attributed to angiogenesis. Thus, anti-angiogenesis has become a strategy for the treatment of breast cancer.

Methods

Cell viability of different concentration treatment groups were detected by Cell Counting Kit-8 assay. The expression of several related genes in the Wnt1 signaling pathway in MDA-MB-231 and Hs-578T cells treated with GLA were measured at both the transcription and translation levels using quantitative real-time PCR analyses and western blotting. Immunofluorescence assay analyzed the nuclear translocation of β-catenin. The microRNA-inhibitor was used to knockdown microRNA-148a (miR-148a) expression. Angiogenic potentials of breast cancer cells were analyzed by enzyme-linked immunosorbent assay (ELISA) and tube formation in vitro.

Results

GLA attenuated angiogenesis by the suppression of miR-148a-mediated Wnt/β-catenin signaling pathway in two human breast cancer cell lines (MDA-MB-231 and Hs-578T). GLA also upregulated the expression of miR-148a in a dose-dependent manner, miR-148a, which could directly target Wnt-3′-untranslated regions (UTRs), and decreased the expression of Wnt1, leading to β-catenin accumulation in the membranes from the cytoplasm and nucleus. Downregulation of miR-148a contributed to the reduction of GLA-induced suppression of the Wnt/β-catenin signaling pathway, the angiogenesis and vascular endothelial grow factor (VEGF) secretion.

Conclusions

Our study identified a molecular mechanism of the GLA inhibition of angiogenesis through the Wnt/β-catenin signaling pathway via miR-148a, suggesting that GLA could serve as an adjuvant chemotherapeutic agent for breast cancer.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-017-3298-1) contains supplementary material, which is available to authorized users.

Underlying Mechanisms for Distant Metastasis - Molecular Biology

BACKGROUND

The formation of distant metastases constitutes a complex process with a variety of different genes and pathways involved. To improve patient survival, it is necessary to understand the underlying mechanisms of metastasis to allow for targeted intervention.

METHODS

This review provides an overview of the general concepts of metastasis, focusing on the most important genes and pathways involved and on interventional strategies.

RESULTS

Cancer cells undergo different steps to form metastasis: most prominently, local invasion, intravasation, survival in the circulation, arrest at a distant organ site and extravasation, micrometastasis formation, and metastatic colonization. In order to pass these steps, different molecular pathways are of major importance: EGF/RAS/RAF/MEK/ERK, PI3K/Akt/mTOR, HGF/Met, Wnt/β-catenin, and VEGF signaling. The HGF/Met regulator MACC1 and the Wnt signaling target S100A4 have been shown to play a major role in the metastatic process. Each gene and pathway provides an opportunity for therapeutic intervention.

CONCLUSION

Since metastasis represents a highly limiting factor in cancer therapy causing 90% of cancer deaths, it is imperative to reveal the underlying mechanisms. This is fundamental for uncovering prognostic markers and new targeted therapy options.

Pharmacologic Manipulation of Wnt Signaling and Cancer Stem Cells

Wnt (Wingless-related integration site)-signaling orchestrates self-renewal programs in normal somatic stem cells as well as in cancer stem cells. Aberrant Wnt signaling is associated with a wide variety of malignancies and diseases. Although our understanding has increased tremendously over the past decade, therapeutic targeting of the dysregulated Wnt pathway remains a challenge. Here we review recent preclinical and clinical therapeutic approaches to target the Wnt pathway.

Celecoxib and 2,5-dimethylcelecoxib inhibit intestinal cancer growth by suppressing the Wnt/β-catenin signaling pathway

We previously reported that celecoxib, a selective COX-2 inhibitor, strongly inhibited human colon cancer cell proliferation by suppressing the Wnt/β-catenin signaling pathway. 2,5-Dimethylcelecoxib (DM-celecoxib), a celecoxib analog that does not inhibit COX-2, has also been reported to have an antitumor effect. In the present study, we elucidated whether DM-celecoxib inhibits intestinal cancer growth, and its underlying mechanism of action. First, we compared the effect of DM-celecoxib with that of celecoxib on the human colon cancer cell lines HCT-116 and DLD-1. 2,5-Dimethylcelecoxib suppressed cell proliferation and inhibited T-cell factor 7-like 2 expression with almost the same strength as celecoxib. 2,5-Dimethylcelecoxib also inhibited the T-cell factor-dependent transcription activity and suppressed the expression of Wnt/β-catenin target gene products cyclin D1 and survivin. Subsequently, we compared the in vivo effects of celecoxib and DM-celecoxib using the Mutyh-/- mouse model, in which oxidative stress induces multiple intestinal carcinomas. Serum concentrations of orally administered celecoxib and DM-celecoxib elevated to the levels enough to suppress cancer cell proliferation. Repeated treatment with celecoxib and DM-celecoxib markedly reduced the number and size of the carcinomas without showing toxicity. These results suggest that the central mechanism for the anticancer effect of celecoxib derivatives is the suppression of the Wnt/β-catenin signaling pathway but not the inhibition of COX-2, and that DM-celecoxib might be a better lead compound candidate than celecoxib for the development of novel anticancer drugs.

Developing drugs that target the Wnt pathway: recent approaches in cancer and neurodegenerative diseases

INTRODUCTION

Wnt/β-catenin signaling is an evolutionarily conserved pathway that has a crucial role in embryonic and adult life. Dysregulation of Wnt/β-catenin pathway has been associated with various diseases, including cancer and neurodegenerative disorders, including Parkinson's disease (PD). Several molecular components of the signaling have been proposed as innovative targets for cancer therapy, and very recently, some of them have been also evaluated as potential therapeutic targets for PD. Areas covered: This review focuses on the role of Wnt/β-catenin pathway in the pathogenensis of cancer and PD, examining some recent therapeutic approaches that are ongoing in preclinical and clinical studies. The possibilities that this signaling offers for diagnosis and prognosis of neoplastic diseases, and the concerns of targeting this pathway are also discussed. Expert opinion: Despite the stimulating results obtained in preclinical studies on cancer and other disease models, the clinical experience with Wnt modulators is still in its infancy, and is mainly restricted to anticancer therapy. Even with concerns of the safety of drugs targeting Wnt signaling, the attention of researchers worldwide is increasing to this issue in terms of their therapeutic potential for diseases such as PD, for which no cure exists.

Expression Patterns of the Wnt Pathway Inhibitors Dickkopf3 and Secreted Frizzled-Related Proteins 1 and 4 in Endometrial Endometrioid Adenocarcinoma: An NRG Oncology/Gynecologic Oncology Group Study

OBJECTIVE

The aim of the study was to determine the differential expression patterns of the wingless-type (Wnt) pathway inhibitors Dkk3 (Dickkopf 3), SFRP1 (secreted frizzled-related protein 1), and SFRP4 in normal müllerian tissue and endometrial endometrioid adenocarcinoma specimens.

METHODS

Messenger RNA (mRNA) and protein levels of the Wnt pathway inhibitors Dkk3, SFRP1, and SFRP4 were evaluated by real-time reverse transcription-polymerase chain reaction and Western blot analysis. A total of 87 human tissue specimens were obtained from 60 women who participated in Gynecologic Oncology Group protocol 210. Twenty-seven normal müllerian tissues, 32 early-stage, and 28 advanced-stage endometrial endometrioid cancer specimens were analyzed.

RESULTS

Median age for this cohort was 60 years, with median body mass index of 32 kg/m. There was a difference in Dkk3 protein expression between normal müllerian tissues and primary endometrial endometrioid adenocarcinoma samples (P = 0.05). There was down-regulation of Dkk3, SFRP1, and SFRP4 mRNA expression in patients with high-grade disease (P = 0.08, 0.06, and 0.05, respectfully). Furthermore, a decrease in SFRP1 and SFPR4 mRNA expression was noted in patients with a diagnosis of locoregional and distant disease recurrence. Lastly, a trend toward decreased progression-free survival in patients with low Dkk3, SFRP1, and SFRP4 mRNA expression levels was noted.

CONCLUSIONS

Wnt pathway inhibitor (Dkk3, sFRP1, and/or sFRP4) expression was down-regulated in patients with high-grade disease and was associated with locoregional and distant disease recurrence. Despite sample size (power) limitations, these results support previous preclinical studies and may suggest a therapeutic role for Wnt signaling in endometrial cancer.

In vitro models of cancer stem cells and clinical applications

Cancer cells, stem cells and cancer stem cells have for a long time played a significant role in the biomedical sciences. Though cancer therapy is more effective than it was a few years ago, the truth is that still none of the current non-surgical treatments can cure cancer effectively. The reason could be due to the subpopulation called “cancer stem cells” (CSCs), being defined as those cells within a tumour that have properties of stem cells: self-renewal and the ability for differentiation into multiple cell types that occur in tumours.

The phenomenon of CSCs is based on their resistance to many of the current cancer therapies, which results in tumour relapse. Although further investigation regarding CSCs is still needed, there is already evidence that these cells may play an important role in the prognosis of cancer, progression and therapeutic strategy. Therefore, long-term patient survival may depend on the elimination of CSCs. Consequently, isolation of pure CSC populations or reprogramming of cancer cells into CSCs, from cancer cell lines or primary tumours, would be a useful tool to gain an in-depth knowledge about heterogeneity and plasticity of CSC phenotypes and therefore carcinogenesis. Herein, we will discuss current CSC models, methods used to characterize CSCs, candidate markers, characteristic signalling pathways and clinical applications of CSCs. Some examples of CSC-specific treatments that are currently in early clinical phases will also be presented in this review.

Novel Small Molecule Inhibitors of Cancer Stem Cell Signaling Pathways

The main aim of oncologists worldwide is to understand and then intervene in the primary tumor initiation and propagation mechanisms. This is essential to allow targeted elimination of cancer cells without altering normal mitotic cells. Currently, there are two main rival theories describing the process of tumorigenesis. According to the Stochastic Model, potentially any cell, once defunct, is capable of initiating carcinogenesis. Alternatively the Cancer Stem Cell (CSC) Model posits that only a small fraction of undifferentiated tumor cells are capable of triggering carcinogenesis. Like healthy stem cells, CSCs are also characterized by a capacity for self-renewal and the ability to generate differentiated progeny, possibly mediating treatment resistance, thus leading to tumor recurrence and metastasis. Moreover, molecular signaling profiles are similar between CSCs and normal stem cells, including Wnt, Notch and Hedgehog pathways. Therefore, development of novel chemotherapeutic agents and proteins (e.g., enzymes and antibodies) specifically targeting CSCs are attractive pharmaceutical candidates. This article describes small molecule inhibitors of stem cell pathways Wnt, Notch and Hedgehog, and their recent chemotherapy clinical trials.

Suppression of β-catenin/TCF transcriptional activity and colon tumor cell growth by dual inhibition of PDE5 and 10

Previous studies suggest the anti-inflammatory drug, sulindac inhibits tumorigenesis by a COX independent mechanism involving cGMP PDE inhibition. Here we report that the cGMP PDE isozymes, PDE5 and 10, are elevated in colon tumor cells compared with normal colonocytes, and that inhibitors and siRNAs can selectively suppress colon tumor cell growth. Combined treatment with inhibitors or dual knockdown suppresses tumor cell growth to a greater extent than inhibition from either isozyme alone. A novel sulindac derivative, ADT-094 was designed to lack COX-1/-2 inhibitory activity but have improved potency to inhibit PDE5 and 10. ADT-094 displayed >500 fold higher potency to inhibit colon tumor cell growth compared with sulindac by activating cGMP/PKG signaling to suppress proliferation and induce apoptosis. Combined inhibition of PDE5 and 10 by treatment with ADT-094, PDE isozyme-selective inhibitors, or by siRNA knockdown also suppresses β-catenin, TCF transcriptional activity, and the levels of downstream targets, cyclin D1 and survivin. These results suggest that dual inhibition of PDE5 and 10 represents novel strategy for developing potent and selective anticancer drugs.

A Second WNT for Old Drugs: Drug Repositioning against WNT-Dependent Cancers

Aberrant WNT signaling underlies cancerous transformation and growth in many tissues, such as the colon, breast, liver, and others. Downregulation of the WNT pathway is a desired mode of development of targeted therapies against these cancers. Despite the urgent need, no WNT signaling-directed drugs currently exist, and only very few candidates have reached early phase clinical trials. Among different strategies to develop WNT-targeting anti-cancer therapies, repositioning of existing drugs previously approved for other diseases is a promising approach. Nonsteroidal anti-inflammatory drugs like aspirin, the anti-leprotic clofazimine, and the anti-trypanosomal suramin are among examples of drugs having recently revealed WNT-targeting activities. In total, 16 human-use drug compounds have been found to be working through the WNT pathway and show promise for their prospective repositioning against various cancers. Advances, hurdles, and prospects of developing these molecules as potential drugs against WNT-dependent cancers, as well as approaches for discovering new ones for repositioning, are the foci of the current review.

S100A4 in Cancer Metastasis: Wnt Signaling-Driven Interventions for Metastasis Restriction

The aberrant activity of Wnt signaling is an early step in the transformation of normal intestinal cells to malignant tissue, leading to more aggressive tumors, and eventually metastases. In colorectal cancer (CRC), metastasis accounts for about 90% of patient deaths, representing the most lethal event during the course of the disease and is directly linked to patient survival, critically limiting successful therapy. This review focuses on our studies of the metastasis-inducing gene S100A4, which we identified as transcriptional target of β-catenin. S100A4 increased migration and invasion in vitro and metastasis in mice. In patient CRC samples, high S100A4 levels predict metastasis and reduced patient survival. Our results link pathways important for tumor progression and metastasis: the Wnt signaling pathway and S100A4, which regulates motility and invasiveness. S100A4 suppression by interdicting Wnt signaling has potential for therapeutic intervention. As proof of principle, we applied S100A4 shRNA systemically and prevented metastasis in mice. Furthermore, we identified small molecule inhibitors from high-throughput screens of pharmacologically active compounds employing an S100A4 promoter-driven reporter. Best hits act, as least in part, via intervening in the Wnt pathway and restricted metastasis in mouse models. We currently translate our findings on restricting S100A4-driven metastasis into clinical practice. The repositioned FDA-approved drug niclosamide, targeting Wnt signaling, is being tested in a prospective phase II clinical trial for treatment of CRC patients. Our assay for circulating S100A4 transcripts in patient blood is used to monitor treatment success.

Repositioning of drugs for intervention in tumor progression and metastasis: Old drugs for new targets

The increasing unraveling of the molecular basis of cancer offers manifold novel options for intervention strategies. However, the discovery and development of new drugs for potential clinical applications is a tremendously time-consuming and costly process. Translating a novel lead candidate compound into an approved clinical drug takes often more than a decade, and the success rate is very low due to versatile efforts including defining its pharmacokinetics, pharmacodynamics, side effects as well as lack of sufficient efficacy. Thus, strategies are needed to minimize time and costs, while maximizing success rates. A very attractive strategy for novel cancer therapeutic options is the repositioning of already approved drugs. These medicines, approved for the treatment of non-malignant disorders, have already passed some early costs and time, have been tested in humans and are ready for clinical trials as anti-cancer drugs. Here we discuss the repositioning of nonsteroidal anti-inflammatory drugs (NSAID), statins, anti-psychotic drugs, anti-helminthic drugs and vitamin D as anti-tumor agents. We focus on their novel actions and potential for inhibition of cancer growth and metastasis by interfering with target molecules and pathways, which drive these malignant processes. Furthermore, important pre-clinical and clinical data are reviewed herein, which elucidate their therapeutic mechanisms which enable their repositioning for cancer therapy and disruption of metastasis.

The Wnt signaling pathway in cancer

The Wnt signaling pathway is critically involved in both the development and homeostasis of tissues via regulation of their endogenous stem cells. Aberrant Wnt signaling has been described as a key player in the initiation of and/or maintenance and development of many cancers, via affecting the behavior of Cancer Stem Cells (CSCs). CSCs are considered by most to be responsible for establishment of the tumor and also for disease relapse, as they possess inherent drug-resistance properties. The development of new therapeutic compounds targeting the Wnt signaling pathway promises new hope to eliminate CSCs and achieve cancer eradication. However, a major challenge resides in developing a strategy efficient enough to target the dysregulated Wnt pathway in CSCs, while being safe enough to not damage the normal somatic stem cell population required for tissue homeostasis and repair. Here we review recent therapeutic approaches to target the Wnt pathway and their clinical applications.