Targeting the Wnt Pathway in Cancer: A Review of Novel Therapeutics

Decreasing of serine/threonine kinase 39 has tumour inhibiting effects on acute myeloid leukaemia by impacting the PI3K/AKT and Wnt/β-catenin signalling cascades

Serine/threonine kinase 39 (STK39) has been identified as a key regulator of tumour progression. However, whether STK39 plays a role in acute myeloid leukaemia (AML) remains undetermined. This work explored the expression and functions of STK39 in AML. STK39 was found to be overexpressed in AML and was negatively correlated with overall survival. Functionally, silencing STK39 inhibited cell proliferation, promoted cell differentiation and induced cell cycle arrest and apoptosis. The tumour inhibiting effects of STK39 downregulation were also verified by an in vivo xenograft tumour assay. Mechanistically, STK39 was closely related to the PI3K/AKT and Wnt/β-catenin signalling cascades in AML. Silencing of STK39 had suppressive effects on the PI3K/AKT and Wnt/β-catenin signalling cascades. The suppressive effect of STK39 silencing on the Wnt/β-catenin signalling cascade was significantly reversed when PI3K/AKT was reactivated. When β-catenin was re-expressed, the tumour-inhibiting effects caused by STK39 silencing were significantly eliminated. Therefore, STK39 plays a crucial role in AML and could be targeted for potential therapeutic purposes in treating AML.

Secreted frizzled-related proteins: A promising therapeutic target for cancer therapy through Wnt signaling inhibition

The Wnt signaling system is a critical pathway that regulates embryonic development and adult homeostasis. Secreted frizzled-related proteins (SFRPs) are extracellular inhibitors of Wnt signaling that act by binding directly to Wnt ligands or Frizzled receptors. SFRPs can act as anti-Wnt agents and suppress cancer growth by blocking the action of Wnt ligands. However, SFRPs are often silenced by promoter methylation in cancer cells, resulting in hyperactivation of the Wnt pathway. Epigenetic modifiers can reverse this silencing and restore SFRPs expression. Despite the potential of SFRPs as a therapeutic target, the effects of SFRPs on tumor development remain unclear. Therefore, a review of the expression of various members of the SFRPs family in different cancers and their potential as therapeutic targets is warranted. This review aims to summarize the current knowledge of SFRPs in cancer, focusing on their expression patterns and their potential as novel therapeutic targets.

Wnt Signaling Inhibitors and Their Promising Role in Tumor Treatment

In a continuous search for the improvement of antitumor therapies, the inhibition of the Wnt signaling pathway has been recognized as a promising target. The altered functioning of the Wnt signaling in human tumors points to the strategy of the inhibition of its activity that would impact the clinical outcomes and survival of patients. Because the Wnt pathway is often mutated or epigenetically altered in tumors, which promotes its activation, inhibitors of Wnt signaling are being intensively investigated. It has been shown that knocking down specific components of the Wnt pathway has inhibitory effects on tumor growth in vivo and in vitro. Thus, similar effects are expected from the application of Wnt inhibitors. In the last decades, molecules acting as inhibitors on the pathway’s specific molecular levels have been identified and characterized. This review will discuss the inhibitors of the canonical Wnt pathway, summarize knowledge on their effectiveness as therapeutics, and debate their side effects. The role of the components frequently mutated in various tumors that are principal targets for Wnt inhibitors is also going to be brought to the reader’s attention. Some of the molecules identified as Wnt pathway inhibitors have reached early stages of clinical trials, and some have only just been discovered. All things considered, inhibition of the Wnt signaling pathway shows potential for the development of future therapies.

A comprehensive review on algal nutraceuticals as prospective therapeutic agent for different diseases

Ongoing research in the food supplement sector provides insightful information regarding algae as a new-generation nutritional supplement and is also referred to as a superfood. Due to the diverse nutritional components, algae have documented numerous health benefits like fighting microbial diseases, hypertension, obesity, and diabetes. Therefore, algae-derived nutraceuticals account for a rapidly expanding market in the food supplements sector. The concept of algal prebiotics and their role in modulating gut microbiota have also been a chief contributor to this. This review evaluates the use of possible algal species and their specific bioactive compounds for the management of several chronic diseases. Proteins, peptides, polysaccharides, phenolics, and vitamins give an insight into the significance of algae in boosting the immune system and improving the body's nutritional makeup. In addition, phyco-compounds such as polysaccharides and polyphenols are also receiving a lot more interest in cosmeceutical applications for protecting skin from photodamage. The incorporation of algae in the diet for the management and prevention of chronic diseases like cancer, lung, and heart disease has been discussed in this review along with their action mechanism. This review provides a brief overview of several bioactive compounds present in micro and macroalgae and their therapeutic effect on lifestyle diseases, gastrointestinal diseases as well as neurodegenerative diseases.

Targeting Signaling Pathway by Curcumin in Osteosarcoma

The most prevalent primary bone malignancy among children and adolescents is osteosarcoma. The high mortality rate of osteosarcoma is due to lung metastasis. Despite the development of multi-agent chemotherapy and surgical resection, patients with osteosarcoma have a high metastasis rate and poor prognosis. Thus, it is necessary to identify novel therapeutic agents to improve the 5-year survival rate of these patients. Curcumin, a phytochemical compound derived from Curcuma longa, has been employed in treating several types of cancers through various mechanisms. Also, in vitro studies have demonstrated that curcumin could inhibit cell proliferation and induce apoptosis in osteosarcoma cells. Development in identifying signaling pathways involved in the pathogenesis of osteosarcoma has provided insight into finding new therapeutic targets for the treatment of this cancer. Targeting MAPK/ERK, PI3k/AKT, Wnt/β-catenin, Notch, and MircoRNA by curcumin has been evaluated to improve outcomes in patients with osteosarcoma. Although curcumin is a potent anti-cancer compound, it has rarely been studied in clinical settings due to its congenital properties such as hydrophobicity and poor bioavailability. In this review, we recapitulate and describe the effect of curcumin in regulating signaling pathways involved in osteosarcoma.

NKD2 is correlated with the occurrence, progression and prognosis of thyroid carcinoma

Background

Thyroid carcinoma (THCA) is the most prevalent type of tumor in endocrine system. NKD2 has been increasingly evidenced to play crucial roles in many cancers, except for THCA. We herein aimed to explore the potential role of NKD2 in THCA.

Methods

Totally 502 THCA patient data were downloaded from TCGA (The Cancer Genome Atlas) database. Overall survival was estimated by Kaplan–Meier method. Gene set enrichment analysis was conducted to obtain significant functional pathways. Wilcoxon rank sum test was used to determine the NKD2 expression differences among various groups. The NKD2 expression was validated in cell lines and tissue microarray.

Results

Significantly higher NKD2 expression was observed in THCA samples compared with adjacent samples, which were successfully verified in cell lines and tissue microarray. Moreover, NKD2 expression gradually elevated along with the increase of TNM Stage, and NKD2 expression was significantly higher in elder THCA patients compared with young patients. NKD2 highly expressed THCA patients had worse prognosis compared with NKD2 low-expressed patients. Furthermore, 53 pathways were significantly activated in the high NKD2 expression patients compared with low NKD2 expression THCA patients.

Conclusions

In summary, high NKD2 expression was probably related to the progression and poor prognosis of THCA. NKD2 is a promising prognostic biomarker and pathogenic target of THCA.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40001-022-00853-2.

Pirfenidone and post-Covid-19 pulmonary fibrosis: invoked again for realistic goals

Pirfenidone (PFN) is an anti-fibrotic drug with significant anti-inflammatory property used for treatment of fibrotic conditions such as idiopathic pulmonary fibrosis (IPF). In the coronavirus disease 2019 (Covid-19) era, severe acute respiratory syndrome 2 (SARS-CoV-2) could initially lead to acute lung injury (ALI) and in severe cases may cause acute respiratory distress syndrome (ARDS) which is usually resolved with normal lung function. However, some cases of ALI and ARDS are progressed to the more severe critical stage of pulmonary fibrosis commonly named post-Covid-19 pulmonary fibrosis which needs an urgent address and proper management. Therefore, the objective of the present study was to highlight the potential role of PFN in the management of post-Covid-19 pulmonary fibrosis. The precise mechanism of post-Covid-19 pulmonary fibrosis is related to the activation of transforming growth factor beta (TGF-β1), which activates the release of extracellular proteins, fibroblast proliferation, fibroblast migration and myofibroblast conversion. PFN inhibits accumulation and recruitment of inflammatory cells, fibroblast proliferation, deposition of extracellular matrix in response to TGFβ1 and other pro-inflammatory cytokines. In addition, PFN suppresses furin (TGFβ1 convertase activator) a protein effector involved in the entry of SARS-CoV-2 and activation of TGFβ1, and thus PFN reduces the pathogenesis of SARS-CoV-2. Besides, PFN modulates signaling pathways such as Wingless/Int (Wnt/β-catenin), Yes-Associated Protein (YAP)/Transcription Co-Activator PDZ Binding Motif (TAZ) and Hippo Signaling Pathways that are involved in the pathogenesis of post-Covid-19 pulmonary fibrosis. In conclusion, the anti-inflammatory and anti-fibrotic properties of PFN may attenuate post-Covid-19 pulmonary fibrosis.

MiRNA-196-5p Promotes Proliferation and Migration in Cholangiocarcinoma via HAND1/Wnt/β-Catenin Signaling Pathway

Accumulating evidence has indicated the crucial role of microRNA-196 in mediating tumor progression, while its significance in cholangiocarcinoma (CCA) remains unclear. In this study, we provided the first evidence that the expression level of miR-196-5p is elevated in both CCA cell lines and clinic specimen. MiR-196-5p inhibition notably suppressed cell proliferation as well as metastasis in CCA cell line HuCCT1. Furthermore, the interaction between miR-196-5p and its downstream molecule HAND1 was verified. Moreover, a series of rescue assay verified that both HAND1 and β-catenin silencing could reverse the abnormal elevated cell proliferation and migration brought by miR-196-5p elevation, indicating that HAND1/Wnt/β-catenin signaling pathway activation is essential for miR-196-5p to exert its roles. In summary, we successfully depict the oncogenic role of miR-196-5p in promoting cell proliferation and migration in CCA via HAND1/Wnt/β-catenin axis.

Myelin and lymphocyte protein serves as a prognostic biomarker and is closely associated with the tumor microenvironment in the nephroblastoma

Nephroblastoma, also known as Wilms' tumor (WT), is the most common renal tumor that occurs in children. Although the efficacy of treatment has been significantly improved by a series of comprehensive treatments, some patients still have poor prognosis. Myelin and lymphocyte (MAL) protein, a highly hydrophobic integrated membrane‐bound protein, has been implicated in many tumors and is also closely linked to kidney development. However, the relationship between MAL and WT has not yet been elucidated. Therefore, we attempted to evaluate the feasibility of MAL as a promising prognosis factor for WT. The differential expression of MAL was investigated using TARGET database and was verified using the Gene Expression Omnibus database and real‐time quantitative PCR. The prognostic ability of MAL was determined using Kaplan–Meier and Cox regression analyses. Pearson correlation analysis was applied to explore the relationship between MAL expression and methylation sites. The ESTIMATE and CIBERSORT algorithms showed that MAL expression was associated with the WT tumor microenvironment. Gene Set Enrichment Analysis (GSEA) indicated that multiple signaling pathways closely associated with tumorigenesis were differentially enriched between the high‐ and low‐MAL groups. In conclusion, our study comprehensively explored the potential of MAL as a prognosis factor for WT. Meanwhile, we also demonstrated that MAL, as a prognostic factor for WT, may be closely related to the tumor microenvironment.

The Potential of Induced Pluripotent Stem Cells to Advance the Treatment of Pancreatic Ductal Adenocarcinoma

Simple Summary

Despite improvements in the treatment of several cancer types, the extremely poor prognosis of pancreatic cancer patients has remained unchanged over the last decades. Therefore, new therapeutic regimens for pancreatic cancer are highly needed. In this review, we will discuss the potential of induced pluripotent stem cells (iPSCs) to generate representative pancreatic cancer models that can aid the development of novel diagnostics and therapeutic strategies. Furthermore, the potential of iPSCs as pancreatic cancer vaccines or as a basis for cellular therapies will be discussed. With promising preclinical results and ongoing clinical trials, the potential of iPSCs to further the treatment of pancreatic cancer is being explored and, in turn, will hopefully provide additional therapies to increase the poor survival rates of this patient population.

Abstract

Advances in the treatment of pancreatic ductal adenocarcinoma (PDAC) using neoadjuvant chemoradiotherapy, chemotherapy, and immunotherapy have had minimal impact on the overall survival of patients. A general lack of immunogenic features and a complex tumor microenvironment (TME) are likely culprits for therapy refractoriness in PDAC. Induced pluripotent stem cells (iPSCs) should be explored as a means to advance the treatment options for PDAC, by providing representative in vitro models of pancreatic cancer development. In addition, iPSCs could be used for tailor-made cellular immunotherapies or as a source of tumor-associated antigens in the context of vaccination.

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

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

Targeting interleukin 6 signaling by monoclonal antibody siltuximab on cholangiocarcinoma

BACKGROUND AND AIM

Cholangiocarcinoma has an unimproved prognosis. Interleukin 6 (IL-6) has an oncogenic potential in some cancer diseases. However, the role of IL-6 in cholangiocarcinoma carcinogenesis is not well understood. The current study investigated the role of IL-6 signaling in cholangiocarcinoma carcinogenesis and efficacy of siltuximab treatment on cholangiocarcinoma in vitro and in vivo.

METHODS

The expression of IL-6 was analyzed on human cholangiocarcinoma cell lines and murine and human cholangiocarcinoma tissues, using reverse transcription real-time polymerase chain reaction and immunohistochemistry. In addition, the effect of anti-IL-6 chimeric monoclonal antibody, siltuximab, was investigated in vitro by proliferation, migration, and two-dimensional and three-dimensional invasion assays and in vivo by xenograft mouse model. Western blot was applied to study the molecular alteration.

RESULTS

Our result shows high expression of IL-6 in human cholangiocarcinoma cells, and IL-6 stimulants enhance cholangiocarcinoma cell proliferation. In addition, murine and human cholangiocarcinoma tissues express significantly higher levels of IL-6, compared with adjacent non-tumor tissues. On the cholangiocarcinoma engineered mouse model, IL-6 level is associated with tumor volume. Taken together, our data indicate an oncogenic potential of IL-6 in cholangiocarcinoma carcinogenesis. Siltuximab sufficiently abrogates IL-6 signaling and inhibits cholangiocarcinoma progression in vitro and in vivo. The results additionally indicate a relative alteration of IL-6 signaling and its molecular targets, such as STAT3, Wnt/β-catenin, and mesenchymal markers.

CONCLUSIONS

Interleukin 6 plays an essential role in cholangiocarcinoma carcinogenesis, and siltuximab has the potential to be considered as a new treatment option for cholangiocarcinoma patients.

Toward Colorectal Cancer Biomarkers: The Role of Genetic Variation, Wnt Pathway, and Long Noncoding RNAs

Colorectal cancer (CRC) is the third leading cause of death worldwide, comprising nearly 8% of cancer-related deaths per year. In South Korea, for example, CRC is the second most common cancer in men, and third in women. This study reports on the association of CRC with genetic variations in long noncoding RNAs, activators, and inhibitors of a cell proliferation pathway. Five normal colon mucosa tissue samples and their matched five-stage IV CRC samples were evaluated (dataset Gene Expression Omnibus accession: GSE50760). We identified more than 5000 differentially expressed genes (DEGs). The Wnt pathway had the greatest portion of DEGs, including activators, inhibitors, and associated long noncoding RNAs (lncRNAs), suggesting the importance of Wnt pathway in CRC. The following genes were aberrantly expressed: WIF1, SFRP4, CD82, WNT2, WNT3, WNT5A, HOTAIR, CRNDE, and UCA1. Notably, HOTAIR is known to silence WIF1, and WIF1 inhibits the Wnt ligands to negatively regulate the pathway. The lncRNA CRNDE positively regulates WNT5A, while UCA1 positively regulates WNT2 and WNT3. We note that HOTAIR was unable to silence WIF1. CRNDE and UCA1 were found to be upregulated, which may explain the high expression of the WIF1 targets. Furthermore, 10 single-nucleotide polymorphisms (SNPs) were identified in five of the candidate genes above. A possible novel SNP in CD82, chr11:44619242T > C, was predicted to introduce a ZBTB7A binding site. These SNPs are hypothesized to contribute to aberrant and discrepant regulation of the Wnt pathway in a context of CRC pathogenesis. These findings collectively inform future research on diagnostics and therapeutics innovation in CRC.

Unmet needs for relapsed or refractory Wilms tumour: Mapping the molecular features, exploring organoids and designing early phase trials - A collaborative SIOP-RTSG, COG and ITCC session at the first SIOPE meeting

Wilms tumour (WT) accounts for about 6% of all childhood cancers and overall survival of WT is about 90% in international protocols. However, for WT subgroups with much poorer prognoses, i.e. typically high-risk (unfavorable) histology and/or relapse, there is an unmet need to better understand the biology of WT and to translate biological findings into clinics through early phase clinical trials that evaluate innovative therapies. The main challenges are the small numbers of children suitable for early phase trials, the genetic heterogeneity of WT and the low number of somatic mutations that are currently considered 'druggable'. Accordingly, a joint meeting between clinical and biology experts from the international cooperative groups of the Renal Tumour Study Group of the International Society of Paediatric Oncology, the Renal Tumour Committee of the Children's Oncology Group and the European Innovative Therapies for Children with Cancer consortium and parents representatives was organised during the first SIOPE meeting in Prague, 2019. We reviewed WT molecular features, ongoing/planned early phase trials and explored available knowledge on organoid technology. The key messages were: (1) relapsed WT should undergo whenever possible thorough molecular characterization and be enrolled in protocols or trials with systematic data collecting and reporting; (2) WT displays few known 'actionable' targets and currently no novel agent has appeared promising; (3) we need to improve the enrolment rate of WT candidates in early phase trials especially for the relatively small subgroup of relapses with an adverse prognostic signature; (4) despite some agnostic early phase trials existing, development of WT-focused trials are warranted; (5) growing organoids with parallel testing of drug panels seems feasible and may direct individual treatment and encourage clinical researchers to incorporate the most promising agents into early phase trials.

Expression profiling on subclasses of primary parotid gland carcinomas

INTRODUCTION

The underlying molecular mechanisms of parotid gland carcinomas (PGC) are still unknown. Knowledge about the tumor-driving signaling pathways is necessary either for diagnostics or developing new therapeutic options in this heterogeneous and rare entity.

MATERIAL AND METHODS

94 matching RNA formalin-fixed and paraffin-embedded tissue samples from PGC and the corresponding non-tumor area, RNA quality and quantity were sufficient for gene expression profiling of 770 genes using the NanoString's nCounter technology. Oncogenic and tumor suppressor genes were examined in the three common PGC tumor entities: adenoid cystic carcinoma (ACC), adenocarcinoma NOS (AC-NOS), and mucoepidermoid carcinoma (MEC).

RESULTS

Expression profiling and subsequent hierarchical cluster analysis clearly differentiated between non-tumor gland tissue samples and PGC. In addition expression pattern of all three entities differed. The extensive pathway analysis proved a prominent dysregulation of the Wnt signaling pathway in the three PGC entities. Moreover, transcript upstream analysis demonstrated a pronounced activation of the PI3K pathway in ACC and MEC.

DISCUSSION

Our findings revealed divergent molecular expression profiles in MEC, ACC and AC-NOS that are presently studied for their potential application in PGC diagnostics. Importantly, identification of Wnt and PI3K signaling in PGC revealed novel options of PGC therapy.

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.

MicroRNA-93-5p promotes epithelial-mesenchymal transition in gastric cancer by repressing tumor suppressor AHNAK expression

BACKGROUND

Gastric cancer (GC) is a common cause of cancer-related mortality worldwide, and microRNAs (miRNAs) have been shown to play an important role in GC development. This study aims to explore the effect of microRNA-93-5p (miR-93-5p) on the epithelial-mesenchymal transition (EMT) in GC, via AHNAK and the Wnt signaling pathway.

METHODS

Microarray-based gene expression analysis was performed to identify GC-related differentially expressed miRNAs and genes. Then the expression of the miR-93-5p was examined in GC tissues and GC cell lines. The targeting relationship between miR-93-5p and AHNAK was verified by a dual luciferase reporter gene assay. In an attempt to ascertain the contributory role of miR-93-5p in GC, miR-93-5p mimic or inhibitor, as well as an AHNAK overexpression vector, were introduced to HGC-27 cells. HGC-27 cell migration and invasive ability, and EMT were assayed using Transwell assay and western blot analysis. Regulation of the Wnt signaling pathway was also assessed using TOP/FOP flash luciferase assay.

RESULTS

miR-93-5p was highly expressed in GC tissue samples and cells. Notably, miR-93-5p could target and negatively regulate AHNAK. Down-regulation of miR-93-5p or overexpression of AHNAK could suppress the migration and invasion abilities, in addition to EMT in GC cells via inactivation of the Wnt signaling pathway.

CONCLUSION

Taken together, downregulation of miR-93-5p attenuated GC development via the Wnt signaling pathway by targeting AHNAK. These findings provide an enhanced understanding of miR-93-5p as a therapeutic target for GC treatment.

Novel therapy for pediatric and adolescent kidney cancer

Pediatric and adolescent renal tumors account for approximately 7% of all new cancer diagnoses in the USA each year. The prognosis and treatment are varied based on factors including the underlying histology and tumor stage, with survival rates ranging from greater than 90% in favorable histology Wilms tumor to almost universally fatal in other disease types, including those patients with advanced stage malignant rhabdoid tumor and renal medullary carcinoma. In recent years, our understanding of the underlying genetic drivers of the different types of pediatric kidney cancer has dramatically increased, opening the door to utilization of new targeted biologic agents alone or in combination with conventional chemotherapy to improve outcomes. Several ongoing clinical trials are investigating the use of a variety of targeted agents in pediatric patients with underlying genetic aberrations. In this manuscript, the underlying biology and early phase clinical trials relevant to pediatric renal cancers are reviewed.

Kinesin Family Member 11 Enhances the Self-Renewal Ability of Breast Cancer Cells by Participating in the Wnt/β-Catenin Pathway

Purpose

Our previous studies have shown that kinesin family member 11 (KIF11) is markedly overexpressed in human breast cancer cells or tissues and positively correlated with distant metastasis and prognosis in patients with breast cancer, suggesting an important role in the regulation of cancer stem cells. Herein, we examined the role of KIF11 in breast cancer stem cells.

Methods

In the current study, we validated our previous findings through analysis of data collected in The Cancer Genome Atlas. Endogenous KIF11 was stably silenced in MCF-7 and SKBR-3 cells. Flow cytometry was used to measure the proportion of side-population (SP) cells. Mammosphere culture and tumor implantation experiments in immunodeficient mice were used to assess the self-renewal ability of breast cancer cells. Real-time polymerase chain reaction, western blot, immunofluorescence staining, luciferase reporter assays and Wnt agonist treatment were conducted to investigate the signaling pathways regulated by KIF11.

Results

We found that the expression level of KIF11 was positively correlated with stem cell-enrichment genes. The proportion of SP cells was significantly reduced in KIF11-silenced cells. Silencing endogenous KIF11 not only reduced the size and number of mammospheres in vitro, but also reduced the ability of breast cancer cells to form tumors in mice. Simultaneously, we found that KIF11 was involved in regulating the activation of the Wnt/β-catenin signaling pathway.

Conclusion

Endogenous KIF11 enhances the self-renewal of breast cancer cells by activating the Wnt/β-catenin signaling pathway, thereby enhancing the characteristics of breast cancer stem cells.

Let-7 as biomarker, prognostic indicator, and therapy for precision medicine in cancer

Abnormal regulation and expression of microRNAs (miRNAs) has been documented in various diseases including cancer. The miRNA let-7 (MIRLET7) family controls developmental timing and differentiation. Let-7 loss contributes to carcinogenesis via an increase in its target oncogenes and stemness factors. Let-7 targets include genes regulating the cell cycle, cell signaling, and maintenance of differentiation. It is categorized as a tumor suppressor because it reduces cancer aggressiveness, chemoresistance, and radioresistance. However, in rare situations let-7 acts as an oncogene, increasing cancer migration, invasion, chemoresistance, and expression of genes associated with progression and metastasis. Here, we review let-7 function as tumor suppressor and oncogene, considering let-7 as a potential diagnostic and prognostic marker, and a therapeutic target for cancer treatment. We explain the complex regulation and function of different let-7 family members, pointing to abnormal processes involved in carcinogenesis. Let-7 is a promising option to complement conventional cancer therapy, but requires a tumor specific delivery method to avoid toxicity. While let-7 therapy is not yet established, we make the case that assessing its tumor presence is crucial when choosing therapy. Clinical data demonstrate that let-7 can be used as a biomarker for rational precision medicine decisions, resulting in improved patient survival.

Transmembrane (TMEM) protein family members: Poorly characterized even if essential for the metastatic process

The majority of cancer-associated deaths are related to secondary tumor formation. This multistep process involves the migration of cancer cells to anatomically distant organs. Metastasis formation relies on cancer cell dissemination and survival in the circulatory system, as well as adaptation to the new tissue notably through genetic and/or epigenetic alterations. A large number of proteins are clearly identified to play a role in the metastatic process but the structures and modes of action of these proteins are essentially unknown or poorly described. In this review, we detail the involvement of members of the transmembrane (TMEM) protein family in the formation of metastases or in the mechanisms leading to cancer cell dissemination such as migration and extra-cellular matrix remodelling. While the phenotype associated with TMEM over or down-expression is clear, the mechanisms by which these proteins allow cancer cell spreading remain, for most of them, unclear. In parallel, the 3D structures of these proteins are presented. Moreover, we proposed that TMEM proteins could be used as prognostic markers in different types of cancers and could represent potential targets for cancer treatment. A better understanding of this heterogeneous family of poorly characterized proteins thus opens perspectives for better cancer patient care.

The small molecule WNT/β-catenin inhibitor CWP232291 blocks the growth of castration-resistant prostate cancer by activating the endoplasmic reticulum stress pathway

BACKGROUND

Androgen receptor (AR)-targeted treatments improve the survival of castration-resistant prostate cancer (CRPC) patients; however, secondary resistance to these agents ultimately occurs in virtually all patients. Therefore, alternative therapeutic targets are urgently needed. Since growing evidence demonstrates that WNT/β-catenin signaling plays an important role in CRPC, the antitumor activity and mechanism of action of CWP232291, a small molecule β-catenin inhibitor, were investigated in prostate cancer.

METHODS

We assessed the antitumor activity of CWP232291 in prostate cancer cell lines and primary cells derived from CRPC patients. The effect of CWP232291 on apoptotic cell death, endoplasmic reticulum (ER) stress, cell viability, and WNT/β-catenin signaling was evaluated by flow cytometry, western blotting, luciferase reporter assay, and fluorescence microscopy. Antitumor efficacy was assessed in two CRPC xenograft mouse models.

RESULTS

CWP232291 induced ER stress, resulting in upregulation of the proapoptotic protein CHOP and activation of caspase-3-dependent apoptosis. In addition, CWP232291 suppressed the expression of β-catenin by affecting WNT-dependent transcriptional activity, and downregulated AR and its splice variants in prostate cancer cells. Antitumor activity was observed in prostate cancer cells in vitro and ex vivo, and antitumor efficacy was observed in vivo.

CONCLUSIONS

Beyond providing preclinical evidence of therapeutic efficacy for the novel small molecule β-catenin inhibitor CWP232291 in CRPC, our results show that inducing ER stress and targeting WNT/β-catenin signaling may be a novel strategy against CRPC.

New Insights about the Wnt/β-Catenin Signaling Pathway in Primary Bone Tumors and Their Microenvironment: A Promising Target to Develop Therapeutic Strategies?

Osteosarcoma and Ewing sarcoma are the most common malignant primary bone tumors mainly occurring in children, adolescents and young adults. Current standard therapy includes multidrug chemotherapy and/or radiation specifically for Ewing sarcoma, associated with tumor resection. However, patient survival has not evolved for the past decade and remains closely related to the response of tumor cells to chemotherapy, reaching around 75% at 5 years for patients with localized forms of osteosarcoma or Ewing sarcoma but less than 30% in metastatic diseases and patients resistant to initial chemotherapy. Despite Ewing sarcoma being characterized by specific EWSR1-ETS gene fusions resulting in oncogenic transcription factors, currently, no targeted therapy could be implemented. It seems even more difficult to develop a targeted therapeutic strategy in osteosarcoma which is characterized by high complexity and heterogeneity in genomic alterations. Nevertheless, the common point between these different bone tumors is their ability to deregulate bone homeostasis and remodeling and divert them to their benefit. Therefore, targeting different actors of the bone tumor microenvironment has been hypothesized to develop new therapeutic strategies. In this context, it is well known that the Wnt/β-catenin signaling pathway plays a key role in cancer development, including osteosarcoma and Ewing sarcoma as well as in bone remodeling. Moreover, recent studies highlight the implication of the Wnt/β-catenin pathway in angiogenesis and immuno-surveillance, two key mechanisms involved in metastatic dissemination. This review focuses on the role played by this signaling pathway in the development of primary bone tumors and the modulation of their specific microenvironment.

Gene Expression Comparison between the Lymph Node-Positive and -Negative Reveals a Peculiar Immune Microenvironment Signature and a Theranostic Role for WNT Targeting in Pancreatic Ductal Adenocarcinoma: A Pilot Study

Over the past several years there has been much debate with regards to the prognostic and clinical significance of pancreatic ductal adenocarcinoma (PDAC) with lymph nodes metastasis. The PDAC gene expression knowledge and the biologic alterations underlying the lymph node involvement convey a clinical implication in dealing with the theranostic window. To this end, we provide an original bioinformatic dissection of the gene expression differences of PDAC according to the nodal involvement from a large public available dataset. Comprehensive transcriptomic analysis from 143 RNA-seq patient's derived samples indicated that WNT increased activation and a peculiar immune microenvironment identify subjects with nodal involvement. In frame of this thinking, we validated the WNT pathway role in increasing the likelihood of lymphatic dissemination in vitro. Moreover, we demonstrated for the first time in a PDAC model the potential therapeutic window that XAV-939-a specific WNT pathway inhibitor-has in re-educating a tumor-permissive immune system. Finally, we outline the potential implication on bystander molecular drivers exerted by WNT molecular inhibition, providing a picture of the proteomic oncogenic landscape changes elicited by XAV-939 on PDAC cells and their clinical implication. Our findings hold the promise to identify novel immune-based therapeutic strategies targeting WNT to enhance PDAC cytotoxicity and restore anti-PDAC immunity in node-positive disease.

Marine anticancer drugs and their relevant targets: a treasure from the ocean

Marine organisms comprising animals and plants are wealthiest sources of bioactive compounds possessing various pharmacological properties specifically: free radical scavenging, antitumor, antimicrobial, analgesic, neuroprotective and immunomodulatory. Marine drugs provide an alternative source to meet the demand of effective, safe and low-cost drugs that are rising with the continuously growing world population. Cancer is one of the leading reasons of mortality in western nations in contrast to communicable diseases of developing nations. In spite of outstanding developments in cancer therapy in past three decades, there is still an insistent necessity for innovative drugs in the area of cancer biology, especially in the unexplored area of marine anticancer compounds. However, recent technological innovations in structure revelation, synthetic creation of new compounds and biological assays have made possible the isolation and clinical assessment of innumerable unique anticancer compounds from marine environment. This review provides an insight into the anticancer research so far conducted in the area of the marine natural products/synthetic derivatives, their possible molecular targets and the current challenges in the drug development. Graphical abstract.

The Wnt signaling pathway: a potential therapeutic target against cancer

The role of the evolutionarily conserved Wnt signaling pathway is well documented in several cellular processes, such as cell proliferation, differentiation, cell motility, and maintenance of the stem cell niche. The very first indication that aberrant Wnt signaling can cause carcinogenesis came from a finding that the mutation of the adenomatous polyposis coli gene (APC) predisposes a person to colorectal carcinoma. Later, with progressing research it became clear that abnormal activation or mutation of the genes related to this pathway could drive tumorigenesis. Here, we review recent advances in research regarding Wnt signaling regulation and its role in several cancer subtypes. Additionally, the utility of Wnt pathway-targeted cancer therapy intervention is also highlighted, with an overview of current approaches to target the Wnt pathway in oncogenesis and the future scopes and challenges associated with them.

Identification of novel triazole inhibitors of Wnt/β-catenin signaling based on the Niclosamide chemotype

Dysregulation of the Wnt signaling pathway is an underlying mechanism in multiple diseases, particularly in cancer. Until recently, identifying agents that target this pathway has been difficult and as a result, no approved drugs exist that specifically target this pathway. We reported previously that the anthelmintic drug Niclosamide inhibits the Wnt/β-catenin signaling pathway and suppresses colorectal cancer cell growth in vitro and in vivo. In an effort to build on this finding, we sought to discover new Wnt/β-catenin inhibitors that expanded the chemotype structural diversity. Here, we asked a specific SAR question unresolved in previous SAR studies of Niclosamide's inhibition of Wnt/β-catenin signaling to identify a new structural class of Wnt/β-catenin signaling inhibitors based on a triazole motif. Similar to Niclosamide, we found that the new triazole derivatives internalized Frizzled-1 GFP receptors, inhibited Wnt/β-catenin signaling in the TOPflash assay and reduced Wnt/β-catenin target gene levels in CRC cells harboring mutations in the Wnt pathway. Moreover, in pilot SAR studies, we found the Wnt/β-catenin SAR trends in the anilide region were generally similar between the two chemical classes of inhibitors. Overall, these studies demonstrate the ability to use the SAR of the Niclosamide salicylanilide chemical class to expand the structural diversity of Wnt/β-catenin inhibitors.

EPH receptor A2 governs a feedback loop that activates Wnt/β-catenin signaling in gastric cancer

The erythropoietin-producing hepatoma (EPH) receptor A2 (EphA2) belongs to the Eph family of receptor tyrosine kinases. EphA2 is highly correlated with the formation of many solid tumors and has been linked to the dysregulation of signaling pathways that promote tumor cell proliferation, migration, and invasion as well as angiogenesis. Deregulation of Wnt signaling is implicated in many forms of human disease including gastric cancer. We previously reported that EphA2 promotes the epithelial–mesenchymal transition through Wnt/β-catenin signaling in gastric cancer. Herein, we present a novel mechanism by which EphA2 regulates Wnt/β-catenin signaling. EphA2 acts as a receptor for Wnt ligands and recruits Axin1 to the plasma membrane by directly binding Dvl2. The EphA2-Dvl2/Axin1 interaction was enhanced by Wnt3a treatment, suggesting that EphA2 acts as a functional receptor for the Wnt/β-catenin pathway and plays a vital role in downstream signaling. We showed that Dvl2 mediates the EphA2-Axin1 interaction by binding to the tyrosine kinase domain of EphA2. We propose that EphA2/Dvl2/Axin1 forms a complex that destabilizes the β-catenin destruction complex and allows β-catenin to translocate to the nucleus and initiate the transcription of c-MYC, the primary Wnt signaling target gene. Intriguingly, c-MYC could bind directly to the EphA2 and Wnt1 promoter to enhance their transcription. The entire process formed an EphA2-mediated feed-forward loop. A small molecular inhibitor of EphA2 potently inhibited the proliferation of gastric cancer in vitro and in vivo, including gastric cancer patient–derived xenografts. Thus, our data identify EphA2 as an excellent candidate for gastric cancer therapy.

Identification of DK419, a potent inhibitor of Wnt/β-catenin signaling and colorectal cancer growth

The Wnt signaling pathway is critical for normal tissue development and is an underlying mechanism of disease when dysregulated. Previously, we reported that the drug Niclosamide inhibits Wnt/β-catenin signaling by decreasing the cytosolic levels of Dishevelled and β-catenin, and inhibits the growth of colon cancers both in vitro and in vivo. Since the discovery of Niclosamide's anthelmintic activity, a growing body of literature indicates that Niclosamide is a multifunctional drug. In an effort to identify derivatives of Niclosamide with improved pharmacokinetic properties that maintain the multifunctional drug activity of Niclosamide for clinical evaluation, we designed DK419, a derivative containing a 1H-benzo[d]imidazole-4-carboxamide substructure, using the structure-activity relationships (SAR) of the Niclosamide salicylanilide chemotype. Similar to Niclosamide, we found DK419 inhibited Wnt/β-catenin signaling, altered cellular oxygen consumption rate and induced production of pAMPK. Moreover, we found DK419 inhibited the growth of CRC tumor cells in vitro, had good plasma exposure when dosed orally, and inhibited the growth of patient derived CRC240 tumor explants in mice dosed orally. DK419, a derivative of Niclosamide with multifunctional activity and improved pharmacokinetic properties, is a promising agent to treat colorectal cancer, Wnt-related diseases and other diseases in which Niclosamide has demonstrated functional activity.

Plasminogen activator inhibitor-1 is associated with the metabolism and development of advanced colonic polyps

Implications of plasminogen activator inhibitor-1 (PAI-1) in colonic polyps remain elusive. A prospective study was conducted with 188 consecutive subjects who underwent colonoscopy at a tertiary referral center. Biochemical parameters, serum PAI-1 levels, PAI-1 single-nucleotide polymorphisms (rs-1799889), and colonic polyp profiles were analyzed at baseline and 24 and 48 weeks postpolypectomy. Of 188 patients (mean age: 56.8 years), 78.7% had adenomas; the median polyp number and size were 2 and 1.2cm, respectively. Multivariate analyses revealed the following baseline associations: PAI-1 levels (95% confidence interval [CI] for estimated β: 0.012-0.223) and polyp pathology (0.294-0.63) with polyp size; polyp size (0.085-0.498) and platelet count (0.013-0.027) with PAI-1 levels. At 24 weeks postpolypectomy, homeostasis model assessment-estimated insulin resistance (HOMA-IR) and platelet count were independently associated with PAI-1 levels. Among patients with colonic adenomas, baseline PAI-1 levels (95% CI odds ratio: 1.06-1.686; cut-off value: >10.65 ng/mL, area under curve: 0.662, P = 0.032) and the PAI-1-rs-17998894G/4G genotype (0.036-0.912) were associated with high-grade dysplasia. Compared with baseline levels, repeated measures analysis of variance showed that PAI-1 levels increased, with concurrent increased HOMA-IR indexes, but decreased alanine transaminase levels and polyp size in follow-up colonoscopies at 24 weeks postpolypectomy. PAI-1 returned to baseline levels, and HOMA-IRs and triglyceride/high-density lipoprotein-cholesterol ratios decreased at 48 weeks postpolypectomy. Taken together, serum PAI-1 levels were positively associated with colonic polyp size and high-grade dysplasia, which was modulated by the PAI-1-rs-17998894G/4G genotype. The beneficial postpolypectomy inflammatory and metabolic alterations might be transiently counter regulated by elevated PAI-1 levels, with a link to HOMA-IR.

Expression of sushi domain containing two reflects the malignant potential of gastric cancer

Hepatic recurrence of gastric cancer (GC) is uncontrollable. Discovery of causative oncogenes and the development of sensitive biomarkers to predict hepatic recurrence are required to improve patients’ outcomes. In this study, recurrence pattern‐specific transcriptome analysis of 57 749 genes was conducted to identify mRNAs specifically associated with hepatic metastasis of patients with stage III GC who underwent curative resection. GC cell lines were subjected to mRNA expression analysis, PCR array analysis, and siRNA‐mediated knockdown. The expression levels of primary cancer tissues from 154 patients with resectable GC were determined and correlated with clinicopathological variables. Among 21 genes significantly overexpressed specifically in patients with hepatic recurrence, Sushi domain containing 2 (SUSD2) was selected as a promising target. PCR array analysis revealed that SUSD2 mRNA levels positively correlated with those of FZD7, CDH2, TGFB1, SPARC, ITGA5, and ZEB1. Functional analysis revealed that knockdown of SUSD2 significantly reduced the proliferation, migration, and invasiveness GC cell lines. Patients with high SUSD2 expression were more likely to experience shorter disease‐free and overall survival. Analysis of the relation between disease recurrence pattern and SUSD2 levels revealed that significantly more patients with hepatic metastases expressed higher levels of SUSD2 mRNA. The cumulative incidence of hepatic recurrence was greater in patients with high SUSD2 expression. In conclusion, SUSD2 likely contributes to the malignant potential of GC and may serve as a novel biomarker that predicts hepatic recurrence after curative resection.

An update of Wnt signalling in endometrial cancer and its potential as a therapeutic target

Endometrial cancer is the most common gynaecological malignancy in developed nations, and its prevalence is rising as women defer or decide not to have children and as obesity rises, both key risk factors. Despite this, treatment options remain limited, particularly for advanced or refractory disease. New genomic analyses have revealed distinct mutational profiles with therapeutic and prognostic potential. Wnt signalling, which is pivotal in embryogenesis, healing and homeostasis, is of importance in the endometrium and has been linked to carcinogenesis. This review aims to update and discuss the current evidence for the role of β-catenin dependent and independent Wnt signalling, including the ROR receptors in the endometrium and its potential as a therapeutic target, in light of recent trials of Wnt-targeted therapy in multiple tumour types.

Pin1 inhibition exerts potent activity against acute myeloid leukemia through blocking multiple cancer-driving pathways

Background

The increasing genomic complexity of acute myeloid leukemia (AML), the most common form of acute leukemia, poses a major challenge to its therapy. To identify potent therapeutic targets with the ability to block multiple cancer-driving pathways is thus imperative. The unique peptidyl-prolyl cis-trans isomerase Pin1 has been reported to promote tumorigenesis through upregulation of numerous cancer-driving pathways. Although Pin1 is a key drug target for treating acute promyelocytic leukemia (APL) caused by a fusion oncogene, much less is known about the role of Pin1 in other heterogeneous leukemia.

Methods

The mRNA and protein levels of Pin1 were detected in samples from de novo leukemia patients and healthy controls using real-time quantitative RT-PCR (qRT-PCR) and western blot. The establishment of the lentiviral stable-expressed short hairpin RNA (shRNA) system and the tetracycline-inducible shRNA system for targeting Pin1 were used to analyze the biological function of Pin1 in AML cells. The expression of cancer-related Pin1 downstream oncoproteins in shPin1 (Pin1 knockdown) and Pin1 inhibitor all-trans retinoic acid (ATRA) treated leukemia cells were examined by western blot, followed by evaluating the effects of genetic and chemical inhibition of Pin1 in leukemia cells on transformed phenotype, including cell proliferation and colony formation ability, using trypan blue, cell counting assay, and colony formation assay in vitro, as well as the tumorigenesis ability using in vivo xenograft mouse models.

Results

First, we found that the expression of Pin1 mRNA and protein was significantly increased in both de novo leukemia clinical samples and multiple leukemia cell lines, compared with healthy controls. Furthermore, genetic or chemical inhibition of Pin1 in human multiple leukemia cell lines potently inhibited multiple Pin1 substrate oncoproteins and effectively suppressed leukemia cell proliferation and colony formation ability in cell culture models in vitro. Moreover, tetracycline-inducible Pin1 knockdown and slow-releasing ATRA potently inhibited tumorigenicity of U937 and HL-60 leukemia cells in xenograft mouse models.

Conclusions

We demonstrate that Pin1 is highly overexpressed in human AML and is a promising therapeutic target to block multiple cancer-driving pathways in AML.

Electronic supplementary material

The online version of this article (10.1186/s13045-018-0611-7) contains supplementary material, which is available to authorized users.

BCL9 Upregulation in Adrenocortical Carcinoma: A Novel Wnt/β-Catenin Activating Event Driving Adrenocortical Malignancy

BACKGROUND

B-Cell CLL/Lymphoma 9 (BCL9) is a recently described oncogene that promotes tumorigenesis via activation of the Wnt/β-Catenin signaling cascade. Though constitutively active Wnt/β-Catenin signaling is a molecular hallmark of adrenocortical carcinoma (ACC), a potential role for BCL9 to promote Wnt/β-Catenin pathway dysregulation in adrenocortical tumorigenesis remains to be elucidated.

STUDY DESIGN

This study involved a retrospective analysis at a tertiary academic referral center of 27 patients with adrenocortical tumors, including in vitro investigation of BCL9. The Wnt signaling pathway polymerase chain reaction (PCR) array analysis queried comparative mRNA expression profiles of canonical Wnt pathway components including BCL9. Real-time quantitative PCR determined BCL9 mRNA expression levels in tumor samples. Expression levels of BCL9 mRNA were evaluated for correlation with tumor characteristics. RNA interference (RNAi) gene silencing was performed in ACC cell lines SW-13 and NCI-H295R to test the role of BCL9 on clonal cell growth.

RESULTS

Expression levels of the BCL9 gene were found to be significantly elevated in ACC compared with normal adrenal tissue (p < 0.05). Furthermore, a significant correlation was observed between BCL9 mRNA levels and the malignant status of adrenocortical tumors (p < 0.05). RNAi gene silencing of BCL9 inhibited clonal cell growth of SW-13 cells (p < 0.05), but not NCI-H295R cells, which carry a constitutively active β-Catenin mutation.

CONCLUSIONS

The gene BCL9 is overexpressed in malignant adrenocortical tumors and promotes clonal ACC cell growth. These findings suggest that BCL9 overexpression may serve as an alternative driver of constitutive Wnt/β-Catenin activation in ACC and could represent a potential molecular and diagnostic marker of tumor malignancy.

NEAT1 acts as an inducer of cancer stem cell-like phenotypes in NSCLC by inhibiting EGCG-upregulated CTR1

Long non-coding RNAs (lncRNAs) play significant roles in the pathogenesis of various cancers, including lung cancer. In this study, we aimed to investigate the biological function of lncRNA nuclear enriched abundant transcript 1 (NEAT1) in cancer stem cells (CSCs). CSCs have been suggested as the main cause of tumor metastasis, tumor recurrence, and chemotherapy resistance. The copper transporter 1 (CTR1) has been the focus of many recent studies because of its correlation with cisplatin (CDDP) resistance. So far, the mechanism of how NEAT1 regulates CSCs in NSCLC remains unknown. In the current study, lung cancer stem cells were enriched from the parental NSCLC cells. We observed that NEAT1 was up-regulated while copper transporter 1 (CTR1) was down-regulated in the enriched NSCLC cancer stem cells. Knockdown of NEAT1 was able to decrease the CSC-like properties in NSCLC cells, while over-expression of NEAT1 could contribute to the stemness respectively. Meanwhile, appropriate doses of EGCG restrained the stemness triggered by over-expressing NEAT1 via inducing CTR1 expression. Wnt signal pathway and epithelial-to-mesenchymal transition (EMT) process were involved in NEAT1-induced CSCs in NSCLC. These findings may suggest a novel role of NEAT1 for NSCLC treatment.

GPCRs: Emerging anti-cancer drug targets

G protein-coupled receptors (GPCRs) constitute the largest and most diverse protein family in the human genome with over 800 members identified to date. They play critical roles in numerous cellular and physiological processes, including cell proliferation, differentiation, neurotransmission, development and apoptosis. Consequently, aberrant receptor activity has been demonstrated in numerous disorders/diseases, and as a result GPCRs have become the most successful drug target class in pharmaceuticals treating a wide variety of indications such as pain, inflammation, neurobiological and metabolic disorders. Many independent studies have also demonstrated a key role for GPCRs in tumourigenesis, establishing their involvement in cancer initiation, progression, and metastasis. Given the growing appreciation of the role(s) that GPCRs play in cancer pathogenesis, it is surprising to note that very few GPCRs have been effectively exploited in pursuit of anti-cancer therapies. The present review provides a broad overview of the roles that various GPCRs play in cancer growth and development, highlighting the potential of pharmacologically modulating these receptors for the development of novel anti-cancer therapeutics.