AXIN1 mutations in hepatocellular carcinomas, and growth suppression in cancer cells by virus-mediated transfer of AXIN1

Genetic Landscape of Multistep Hepatocarcinogenesis

Hepatocellular carcinoma (HCC) is a major cause of cancer-related death worldwide. Although several targeted therapy agents are available for advanced HCC, their antitumor efficacy remains limited. As the complex genetic landscape of HCC would compromise the antitumor efficacy of targeted therapy, a deeper understanding of the genetic landscape of hepatocarcinogenesis is necessary. Recent comprehensive genetic analyses have revealed the driver genes of HCC, which accumulate during the multistage process of hepatocarcinogenesis, facilitating HCC genetic heterogeneity. In addition, as early genetic changes may represent key therapeutic targets, the genetic landscapes of early HCC and precancerous liver tissues have been characterized in recent years, in parallel with the advancement of next-generation sequencing analysis. In this review article, we first summarize the landscape of the liver cancer genome and its intratumor heterogeneity. We then introduce recent insight on early genetic alterations in hepatocarcinogenesis, especially those in early HCC and noncancerous liver tissues. Finally, we summarize the multistep accumulation of genetic aberrations throughout cancer progression and discuss the future perspective towards the clinical application of this genetic information.

In vivo genome-editing screen identifies tumor suppressor genes that cooperate with Trp53 loss during mammary tumorigenesis

Breast cancer is a heterogeneous disease that comprises multiple histological and molecular subtypes. To gain insight into mutations that drive breast tumorigenesis, we describe a pipeline for the identification and validation of tumor suppressor genes. Based on an in vivo genome‐wide CRISPR/Cas9 screen in Trp53^+/– heterozygous mice, we identified tumor suppressor genes that included the scaffold protein Axin1, the protein kinase A regulatory subunit gene Prkar1a, as well as the proof‐of‐concept genes Pten, Nf1, and Trp53 itself. Ex vivo editing of primary mammary epithelial organoids was performed to further interrogate the roles of Axin1 and Prkar1a. Increased proliferation and profound changes in mammary organoid morphology were observed for Axin1/Trp53 and Prkar1a/Trp53 double mutants compared to Pten/Trp53 double mutants. Furthermore, direct in vivo genome editing via intraductal injection of lentiviruses engineered to express dual short‐guide RNAs revealed that mutagenesis of Trp53 and either Prkar1a, Axin1, or Pten markedly accelerated tumor development compared to Trp53‐only mutants. This proof‐of‐principle study highlights the application of in vivo CRISPR/Cas9 editing for uncovering cooperativity between defects in tumor suppressor genes that elicit mammary tumorigenesis.

PNU-74654 Suppresses TNFR1/IKB Alpha/p65 Signaling and Induces Cell Death in Testicular Cancer

Testicular cancer (TC) is a rare malignancy worldwide and is the most common malignancy in males aged 15-44 years. The Wnt/β-catenin signaling pathway mediates numerous essential cellular functions and has potentially important effects on tumorigenesis and cancer progression. The search for drugs to inhibit this pathway has identified a small molecule, PNU-74654, as an inhibitor of the β-catenin/TCF4 interaction. We evaluated the therapeutic role of PNU-74654 in two TC cell lines, NCCIT and NTERA2, by measuring cell viability, cell cycle transition and cell death. Potential pathways were evaluated by protein arrays and Western blots. PNU-74654 decreased cell viability and induced apoptosis of TC cells, with significant increases in the sub G1, Hoechst-stained, Annexin V-PI-positive rates. PNU-74654 treatment of both TC cell lines inhibited the TNFR1/IKB alpha/p65 pathway and the execution phase of apoptosis. Our findings demonstrate that PNU-74654 can induce apoptosis in TC cells through mechanisms involving the execution phase of apoptosis and inhibition of TNFR1/IKB alpha/p65 signaling. Therefore, small molecules such as PNU-74654 may identify potential new treatment strategies for TC.

Wnt/β-catenin signalling: function, biological mechanisms, and therapeutic opportunities

The Wnt/β-catenin pathway comprises a family of proteins that play critical roles in embryonic development and adult tissue homeostasis. The deregulation of Wnt/β-catenin signalling often leads to various serious diseases, including cancer and non-cancer diseases. Although many articles have reviewed Wnt/β-catenin from various aspects, a systematic review encompassing the origin, composition, function, and clinical trials of the Wnt/β-catenin signalling pathway in tumour and diseases is lacking. In this article, we comprehensively review the Wnt/β-catenin pathway from the above five aspects in combination with the latest research. Finally, we propose challenges and opportunities for the development of small-molecular compounds targeting the Wnt signalling pathway in disease treatment.

Disruption of beta-catenin dependent Wnt signaling in colon cancer cells remodels the microenvironment to promote tumor invasion

The recent classification of colon cancer into molecular subtypes revealed that patients with the poorest prognosis harbor tumors with the lowest levels of Wnt signaling. This is contrary to the general understanding that overactive Wnt signaling promotes tumor progression from early initiation stages through to the later stages including invasion and metastasis. Here, we directly test this assumption by reducing the activity of ß-catenin-dependent Wnt signaling in colon cancer cell lines at either an upstream or downstream step in the pathway. We determine that Wnt-reduced cancer cells exhibit a more aggressive disease phenotype, including increased mobility in vitro and disruptive invasion into mucosa and smooth muscle in an orthotopic mouse model. RNA sequencing reveals that interference with Wnt signaling leads to an upregulation of gene programs that favor cell migration and invasion and a downregulation of inflammation signatures in the tumor microenvironment. We identify a set of upregulated genes common among the Wnt perturbations that are predictive of poor patient outcomes in early-invasive colon cancer. Our findings suggest that while targeting Wnt signaling may reduce tumor burden, an inadvertent side effect is the emergence of invasive cancer. Implications: Decreased Wnt signaling in colon tumors leads to a more aggressive disease phenotype due to an upregulation of gene programs favoring cell migration in the tumor and downregulation of inflammation programs in the tumor microenvironment; these impacts must be carefully considered in developing Wnt-targeting therapies.

Association of AXIN1 With Parkinson's Disease in a Taiwanese Population

Objective

A meta-analysis of locus-based genome-wide association studies recently identified a relationship between AXIN1 and Parkinson’s disease (PD). Few studies of Asian populations, however, have reported such a genetic association. The influences of rs13337493, rs758033, and rs2361988, three PD-associated genetic variants of AXIN1, were investigated in the present study because AXIN1 is related to Wnt/β-catenin signaling.

Methods

A total of 2,418 individuals were enrolled in our Taiwanese cohort for analysis of the genotypic and allelic frequency. Polymerase chain reaction–restriction fragment length polymorphism analysis was employed for rs13337493 genotyping, and the Agena MassARRAY platform (Agena Bioscience, San Diego, CA, USA) was used for rs758033 and rs2361988 genotyping in 672 patients with PD and 392 controls. Taiwan Biobank data of another 1,354 healthy controls were subjected to whole-genome sequencing performed using Illumina platforms at approximately 30× average depth.

Results

Our results revealed that rs758033 {odds ratios [OR] (95% confidence interval [CI]) = 0.267 [0.064, 0.795], p = 0.014} was associated with the risk of PD, and there was a trend toward a protective effect of rs2361988 (OR [95% CI] = 0.296 [0.071, 0.884], p = 0.026) under the recessive model. The TT genotype of rs758033 (OR [95% CI] = 0.271 [0.065, 0.805], p = 0.015) and the CC genotype of rs2361988 (OR [95% CI] = 0.305 [0.073, 0.913], p = 0.031) were less common in the PD group than in the non-PD group.

Conclusion

Our findings indicate that the rs758033 and rs2361988 polymorphisms of AXIN1 may affect the risk of PD in the Taiwanese population.

Naked cuticle inhibits wingless signaling in Drosophila wing development

Wnt signaling is one of the major signaling pathways that regulate cell differentiation, tissue patterning and stem cell homeostasis and its dysfunction causes many human diseases, such as cancer. It is of tremendous interests to understand how Wnt signaling is regulated in a precise manner both temporally and spatially. Naked cuticle (Nkd) acts as a negative-feedback inhibitor for Wingless (Wg, a fly Wnt) signaling in Drosophila embryonic development. However, the role of Nkd remains controversial in later fly development, particularly on the canonical Wg pathway. In the present study, we show that nkd is essential for wing pattern formation, such that both gain and loss of nkd result in the disruption of Wg target expression in larvae stage and abnormal adult wing morphologies. Furthermore, we demonstrate that a thirty amino acid fragment in Nkd, identified previously in Wharton lab, is critical for the canonical Wg signaling, but is dispensable for Wg/planar cell polarity pathway. Putting aside the pleiotropic nature of nkd function, i.e. its role in the Decapentaplegic signaling, we conclude that Nkd universally inhibits the canonical Wg pathway across a life span of Drosophila development.

Bortezomib potentiates antitumor activity of mitoxantrone through dampening Wnt/β-catenin signal pathway in prostate cancer cells

BACKGROUND

Bortezomib (BZM), alone or in combination with other chemotherapies, has displayed strong anticancer effects in several cancers. The efficacy of the combination of BZM and mitoxantrone (MTX) in treating prostate cancer remains unknown.

METHODS

Anticancer effects of combination of BZM and MTX were determined by apoptosis and proliferation assay in vivo and in vitro. Expression of β-Catenin and its target genes were characterized by western blot and Real-time PCR.

RESULTS

BZM significantly enhanced MTX-induced antiproliferation in vivo and in vitro. Mice administered a combination of BZM and MTX displayed attenuated tumor growth and prolonged survival. BZM significantly attenuated MTX-induced apoptosis. Moreover, the combination of BZM and MTX contributed to inhibition of the Wnt/β-Catenin signaling pathway compared to monotherapy.

CONCLUSIONS

This study demonstrates that BZM enhances MTX-induced anti-tumor effects by inhibiting the Wnt/β-Catenin signaling pathway in prostate cancer cells.

An Overview of the Genomic Characterization of Hepatocellular Carcinoma

Tumor classifications based on alterations in the genome, epigenome, or proteome have revealed distinct tumor subgroups that are associated with clinical outcomes. Several landmark studies have demonstrated that such classifications can significantly improve patient outcomes by enabling tailoring of therapy to specific alterations in cancer cells. Since cancer cells accumulate numerous alterations in many cancer-related genes, it is a daunting task to find and confirm important cancer-promoting alterations as therapeutic targets or biomarkers that can predict clinical outcomes such as survival and response to treatments. To aid further advances, we provide here an overview of the current understanding of molecular and genomic subtypes of hepatocellular carcinoma (HCC). System-level integration of data from multiple studies and development of new technical platforms for analyzing patient samples hold great promise for the discovery of new targets for treatment and correlated biomarkers, leading to personalized medicine for treatment of HCC patients.

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.

Wnt/β-catenin signaling in cancers and targeted therapies

Wnt/β-catenin signaling has been broadly implicated in human cancers and experimental cancer models of animals. Aberrant activation of Wnt/β-catenin signaling is tightly linked with the increment of prevalence, advancement of malignant progression, development of poor prognostics, and even ascendence of the cancer-associated mortality. Early experimental investigations have proposed the theoretical potential that efficient repression of this signaling might provide promising therapeutic choices in managing various types of cancers. Up to date, many therapies targeting Wnt/β-catenin signaling in cancers have been developed, which is assumed to endow clinicians with new opportunities of developing more satisfactory and precise remedies for cancer patients with aberrant Wnt/β-catenin signaling. However, current facts indicate that the clinical translations of Wnt/β-catenin signaling-dependent targeted therapies have faced un-neglectable crises and challenges. Therefore, in this study, we systematically reviewed the most updated knowledge of Wnt/β-catenin signaling in cancers and relatively targeted therapies to generate a clearer and more accurate awareness of both the developmental stage and underlying limitations of Wnt/β-catenin-targeted therapies in cancers. Insights of this study will help readers better understand the roles of Wnt/β-catenin signaling in cancers and provide insights to acknowledge the current opportunities and challenges of targeting this signaling in cancers.

The multidimensional role of the Wnt/β-catenin signaling pathway in human malignancies

Several signaling pathways have been identified as important for developmental processes. One of such important cascades is the Wnt/β-catenin signaling pathway, which can regulate various physiological processes such as embryonic development, tissue homeostasis, and tissue regeneration; while its dysregulation is implicated in several pathological conditions especially cancers. Interestingly, deregulation of the Wnt/β-catenin pathway has been reported to be closely associated with initiation, progression, metastasis, maintenance of cancer stem cells, and drug resistance in human malignancies. Moreover, several genetic and experimental models support the inhibition of the Wnt/β-catenin pathway to answer the key issues related to cancer development. The present review focuses on different regulators of Wnt pathway and how distinct mutations, deletion, and amplification in these regulators could possibly play an essential role in the development of several cancers such as colorectal, melanoma, breast, lung, and leukemia. Additionally, we also provide insights on diverse classes of inhibitors of the Wnt/β-catenin pathway, which are currently in preclinical and clinical trial against different cancers.

DNA and RNA Sequencing Recapitulated Aberrant Tumor Metabolism in Liver Cancer Cell Lines

AIM

Metabolic reprogramming has recently attracted extensive attention for understanding cancer development. We aimed to demonstrate a genomic and transcriptomic landscape of metabolic reprogramming underlying liver cancer cell lines.

METHODS

We investigated metabolic aberrant at both the transcriptome and genome levels using transcriptome and whole-exome sequencing data from 12 human liver cancer cell lines (hLCCLs) and one normal liver cell line.

RESULTS

Three subgroups of hLCCLs characterized from transcriptome sequencing data exhibit significantly different aberrations in various metabolic processes, including amino acid, lipid, energy, and carbohydrate metabolism. Furthermore, whole-exome sequencing revealed distinct mutational signatures among different subgroups of hLCCLs and identified a total of 19 known driver genes implicated in metabolism.

CONCLUSION

Our findings highlighted differential metabolic mechanisms in the development of liver cancer and provided a resource for further investigating its metabolic mechanisms.

Astrocyte elevated gene-1 (AEG-1): A key driver of hepatocellular carcinoma (HCC)

An array of human cancers, including hepatocellular carcinoma (HCC), overexpress the oncogene Astrocyte elevated gene-1 (AEG-1). It is now firmly established that AEG-1 is a key driver of carcinogenesis, and enhanced expression of AEG-1 is a marker of poor prognosis in cancer patients. In-depth studies have revealed that AEG-1 positively regulates different hallmarks of HCC progression including growth and proliferation, angiogenesis, invasion, migration, metastasis and resistance to therapeutic intervention. By interacting with a plethora of proteins as well as mRNAs, AEG-1 regulates gene expression at transcriptional, post-transcriptional, and translational levels, and modulates numerous pro-tumorigenic and tumor-suppressive signal transduction pathways. Even though extensive research over the last two decades using various in vitro and in vivo models has established the pivotal role of AEG-1 in HCC, effective targeting of AEG-1 as a therapeutic intervention for HCC is yet to be achieved in the clinic. Targeted delivery of AEG-1 small interfering ribonucleic acid (siRNA) has demonstrated desired therapeutic effects in mouse models of HCC. Peptidomimetic inhibitors based on protein-protein interaction studies has also been developed recently. Continuous unraveling of novel mechanisms in the regulation of HCC by AEG-1 will generate valuable knowledge facilitating development of specific AEG-1 inhibitory strategies. The present review describes the current status of AEG-1 in HCC gleaned from patient-focused and bench-top studies as well as transgenic and knockout mouse models. We also address the challenges that need to be overcome and discuss future perspectives on this exciting molecule to transform it from bench to bedside.

Functional interplay between long non-coding RNAs and the Wnt signaling cascade in osteosarcoma

Osteosarcoma is a common and highly malignant bone tumor among children, adolescents and young adults. However, the underlying molecular mechanisms remain largely unexplored. LncRNAs are transcripts with no or limited protein-coding capacity in human genomes, and have been demonstrated to play crucial functions in initiation, progression, therapeutic resistance, recurrence and metastasis of tumor. Considerable studies revealed a dysregulated lncRNA expression pattern in osteosarcoma, which may act as oncogenes or suppressors to regulate osteosarcoma progression. Wnt signaling pathway is an important cascade in tumorigenesis by modulation of pleiotropic biological functions including cell proliferation, apoptosis, differentiation, stemness, genetic stability and chemoresistance. Hyperactivation or deficiency of key effectors in Wnt cascade is a common event in many osteosarcoma patients. Recently, increasing evidences have suggested that lncRNAs could interplay with component of Wnt pathway, and thereby contribute to osteosarcoma onset, progression and dissemination. In this review, we briefly summarize Wnt signaling-related lncRNAs in osteosarcoma progression, aiming to gain insights into their underlying crosstalk as well as clinical application in osteosarcoma therapeutic modalities.

Discovery of 2-(3-(3-Carbamoylpiperidin-1-yl)phenoxy)acetic Acid Derivatives as Novel Small-Molecule Inhibitors of the β-Catenin/B-Cell Lymphoma 9 Protein-Protein Interaction

The β-catenin/B-cell lymphoma 9 (BCL9) protein-protein interaction (PPI) is a potential target for the suppression of hyperactive Wnt/β-catenin signaling that is vigorously involved in cancer initiation and development. Herein, we describe the medicinal chemistry optimization of a screening hit to yield novel small-molecule inhibitors of the β-catenin/BCL9 interaction. The best compound 30 can disrupt the β-catenin/BCL9 interaction with a K_i of 3.6 μM in AlphaScreen competitive inhibition assays. Cell-based experiments revealed that 30 selectively disrupted the β-catenin/BCL9 PPI, while leaving the β-catenin/E-cadherin PPI unaffected, dose-dependently suppressed Wnt signaling transactivation, downregulated oncogenic Wnt target gene expression, and on-target selectively inhibited the growth of cancer cells harboring aberrant Wnt signaling. This compound with a new chemotype can serve as a lead compound for further optimization of inhibitors for β-catenin/BCL9 PPI.

Obesity and intestinal stem cell susceptibility to carcinogenesis

Background

Obesity is a top public health problem associated with an increase in colorectal cancer incidence. Stem cells are the chief cells in tissue homeostasis that self-renew and differentiate into other cells to regenerate the organ. It is speculated that an increase in stem cell pool makes cells susceptible to carcinogenesis. In this review, we looked at the recent investigations linking obesity/high-fat diet-induced obesity to intestinal carcinogenesis with regard to intestinal stem cells and their niche.

Findings

High-fat diet-induced obesity may rise intestinal carcinogenesis by increased Intestinal stem cells (ISC)/progenitor’s population, stemness, and niche independence through activation of PPAR-δ with fatty acids, hormonal alterations related to obesity, and low-grade inflammation. However, these effects may possibly relate to the interaction between fats and carbohydrates, and not a fatty acid per se. Nonetheless, literature studies are inconsistency in their results, probably due to the differences in the diet components and limitations of genetic models used.

Conclusion

High-fat diet-induced obesity affects carcinogenesis by changing ISC proliferation and function. However, a well-matched diet and the reliable colorectal cancer models that mimic human carcinogenesis is necessary to clearly elucidate the influence of high-fat diet-induced obesity on ISC behavior.

Case Report: Cetuximab in Combination With Chemotherapy for the Treatment of Multifocal Hepatic Metastases From Colorectal Cancer Guided by Genetic Tests

Hepatic metastases were reported in up to 70% of colorectal cancer patients, among which multifocal hepatic metastasis represents one of the complications that lead to poor prognosis. The majority of the patients carrying multifocal hepatic metastases required pharmaceutical treatments to reduce the tumor size prior to surgical resection. However, the clinical responses to pharmaceutical agents were difficult to predict due to the heterogeneous nature of the multifocal tumors. Here, we report a case with multifocal hepatic metastases from colorectal cancer that was resistant to the primary chemotherapy and Bevacizumab plus chemotherapy, but responded to the combined therapy of Cetuximab and FOLFOX. Genetic tests had revealed that the tumor was highly metastatic due to the mutations of the WNT signaling pathway, and the metastatic tumors might be sensitive to Cetuximab. Consistent with the molecular characterizations, the metastatic tumors continue to emerge after chemotherapy, and rapidly relapsed in great numbers after liver resection. However, the combined therapy of Cetuximab and FOLFOX guided by the genetic tests significantly reduced the size and number of metastatic tumors. To conclude, deciphering the mutation profiles of multifocal metastatic tumors may guide the determination of treatment tactics, which may benefit the patients with non-resectable advanced carcinoma.

Evaluation of AXIN1 and AXIN2 as targets of tankyrase inhibition in hepatocellular carcinoma cell lines

AXIN1 mutations are observed in 8-10% of hepatocellular carcinomas (HCCs) and originally were considered to support tumor growth by aberrantly enhancing β-catenin signaling. This view has however been challenged by reports showing neither a clear nuclear β-catenin accumulation nor clearly enhanced expression of β-catenin target genes. Here, using nine HCC lines, we show that AXIN1 mutation or siRNA mediated knockdown contributes to enhanced β-catenin signaling in all AXIN1-mutant and non-mutant lines, also confirmed by reduced signaling in AXIN1-repaired SNU449 cells. Both AXIN1 and AXIN2 work synergistically to control β-catenin signaling. While in the AXIN1-mutant lines, AXIN2 is solely responsible for keeping signaling in check, in the non-mutant lines both AXIN proteins contribute to β-catenin regulation to varying levels. The AXIN proteins have gained substantial interest in cancer research for a second reason. Their activity in the β-catenin destruction complex can be increased by tankyrase inhibitors, which thus may serve as a therapeutic option to reduce the growth of β-catenin-dependent cancers. At concentrations that inhibit tankyrase activity, some lines (e.g. HepG2, SNU398) were clearly affected in colony formation, but in most cases apparently independent from effects on β-catenin signaling. Overall, our analyses show that AXIN1 inactivation leads to enhanced β-catenin signaling in HCC cell lines, questioning the strong statements that have been made in this regard. Enhancing AXIN activity by tankyrase monotherapy provides however no effective treatment to affect their growth exclusively through reducing β-catenin signaling.

Mutant p53 Gain-of-Function: Role in Cancer Development, Progression, and Therapeutic Approaches

Frequent p53 mutations (mutp53) not only abolish tumor suppressor capacities but confer various gain-of-function (GOF) activities that impacts molecules and pathways now regarded as central for tumor development and progression. Although the complete impact of GOF is still far from being fully understood, the effects on proliferation, migration, metabolic reprogramming, and immune evasion, among others, certainly constitute major driving forces for human tumors harboring them. In this review we discuss major molecular mechanisms driven by mutp53 GOF. We present novel mechanistic insights on their effects over key functional molecules and processes involved in cancer. We analyze new mechanistic insights impacting processes such as immune system evasion, metabolic reprogramming, and stemness. In particular, the increased lipogenic activity through the mevalonate pathway (MVA) and the alteration of metabolic homeostasis due to interactions between mutp53 and AMP-activated protein kinase (AMPK) and Sterol regulatory element-binding protein 1 (SREBP1) that impact anabolic pathways and favor metabolic reprograming. We address, in detail, the impact of mutp53 over metabolic reprogramming and the Warburg effect observed in cancer cells as a consequence, not only of loss-of-function of p53, but rather as an effect of GOF that is crucial for the imbalance between glycolysis and oxidative phosphorylation. Additionally, transcriptional activation of new targets, resulting from interaction of mutp53 with NF-kB, HIF-1α, or SREBP1, are presented and discussed. Finally, we discuss perspectives for targeting molecules and pathways involved in chemo-resistance of tumor cells resulting from mutp53 GOF. We discuss and stress the fact that the status of p53 currently constitutes one of the most relevant criteria to understand the role of autophagy as a survival mechanism in cancer, and propose new therapeutic approaches that could promote the reduction of GOF effects exercised by mutp53 in cancer.

TMEM9-v-ATPase Activates Wnt/β-Catenin Signaling Via APC Lysosomal Degradation for Liver Regeneration and Tumorigenesis

BACKGROUND AND AIMS

How Wnt signaling is orchestrated in liver regeneration and tumorigenesis remains elusive. Recently, we identified transmembrane protein 9 (TMEM9) as a Wnt signaling amplifier.

APPROACH AND RESULTS

TMEM9 facilitates v-ATPase assembly for vesicular acidification and lysosomal protein degradation. TMEM9 is highly expressed in regenerating liver and hepatocellular carcinoma (HCC) cells. TMEM9 expression is enriched in the hepatocytes around the central vein and acutely induced by injury. In mice, Tmem9 knockout impairs hepatic regeneration with aberrantly increased adenomatosis polyposis coli (Apc) and reduced Wnt signaling. Mechanistically, TMEM9 down-regulates APC through lysosomal protein degradation through v-ATPase. In HCC, TMEM9 is overexpressed and necessary to maintain β-catenin hyperactivation. TMEM9-up-regulated APC binds to and inhibits nuclear translocation of β-catenin, independent of HCC-associated β-catenin mutations. Pharmacological blockade of TMEM9-v-ATPase or lysosomal degradation suppresses Wnt/β-catenin through APC stabilization and β-catenin cytosolic retention.

CONCLUSIONS

Our results reveal that TMEM9 hyperactivates Wnt signaling for liver regeneration and tumorigenesis through lysosomal degradation of APC.

Therapeutic targeting of the oncogenic Wnt signaling pathway for treating colorectal cancer and other colonic disorders

The canonical Wnt pathway is one of the key cellular signaling cascades that regulates, via the transcriptional co-activator β-catenin, numerous embryogenic developmental processes, as well as tissue homeostasis. It is therefore not surprising that misregulation of the Wnt/β-catenin pathway has been implicated in carcinogenesis. Aberrant Wnt signaling has been reported in a variety of malignancies, and its role in both hereditary and sporadic colorectal cancer (CRC), has been the subject of intensive study. Interestingly, the vast majority of colorectal tumors harbor mutations in the tumor suppressor gene adenomatous polyposis coli (APC). The Wnt pathway is complex, and despite decades of research, the mechanisms that underlie its functions are not completely known. Thus, although the Wnt cascade is an attractive target for therapeutic intervention against CRC, one of the malignancies with the highest morbidity and mortality rates, achieving efficacy and safety is yet extremely challenging. Here, we review the current knowledge of the Wnt different epistatic signaling components and the mechanism/s by which the signal is transduced in both health and disease, focusing on CRC. We address some of the important questions in the field and describe various therapeutic strategies designed to combat unregulated Wnt signaling, the development of targeted therapy approaches and the emerging challenges that are associated with these advanced methods.

Roles of the Wnt Signaling Pathway in Head and Neck Squamous Cell Carcinoma

Head and neck squamous cell carcinoma (HNSCC) is the most common type of head and neck tumor. It is a high incidence malignant tumor associated with a low survival rate and limited treatment options. Accumulating conclusions indicate that the Wnt signaling pathway plays a vital role in the pathobiological process of HNSCC. The canonical Wnt/β-catenin signaling pathway affects a variety of cellular progression, enabling tumor cells to maintain and further promote the immature stem-like phenotype, proliferate, prolong survival, and gain invasiveness. Genomic studies of head and neck tumors have shown that although β-catenin is not frequently mutated in HNSCC, its activity is not inhibited by mutations in upstream gene encoding β-catenin, NOTCH1, FAT1, and AJUBA. Genetic defects affect the components of the Wnt pathway in oral squamous cell carcinoma (OSCC) and the epigenetic mechanisms that regulate inhibitors of the Wnt pathway. This paper aims to summarize the groundbreaking discoveries and recent advances involving the Wnt signaling pathway and highlight the relevance of this pathway in head and neck squamous cell cancer, which will help provide new insights into improving the treatment of human HNSCC by interfering with the transcriptional signaling of Wnt.

Knockdown of NCOA2 Inhibits the Growth and Progression of Gastric Cancer by Affecting the Wnt Signaling Pathway-Related Protein Expression

Objective:

The aim of the study is to determine the role of nuclear receptor coactivator 2 in cell proliferation and invasion ability of gastric cancer cells and to explore its possible mechanisms.

Methods:

Immunohistochemical staining was used to determine NCOA2 gene expression in gastric cancer. Western blotting was used to detect Wnt signal pathways–related protein expression. Colony formation assays, Cell Counting Kit-8 assays, and transwell assays were used to determine cell proliferation, metastasis, and invasion ability of gastric cancer cells. A flow cytometric apoptosis tests determine gastric cancer cell apoptosis ability after inhibition of the expression of nuclear receptor coactivator 2. Subcutaneous mouse models were used to determine the gastric cancer growth and peritoneal metastasis differences after inhibition the expression of nuclear receptor coactivator 2.

Results:

The expression of nuclear receptor coactivator 2 in gastric cancer cells is high (P < .01), including lymph node metastasis, TNM staging, and gender differences in nuclear receptor coactivator 2 expression were statistically significant (P < .01). Short interfering nuclear receptor coactivator 2 could inhibit the proliferation and invasion ability of gastric cancer cells. Short interfering nuclear receptor coactivator 2 promotes the apoptosis of gastric cancer cells. Animal experiments showed that short interfering nuclear receptor coactivator 2 could inhibit the growth and invasion of gastric cancer-transplantable tumors. Knockdown of the expression of nuclear receptor coactivator 2 inhibited the Wnt/β-catenin signaling pathway in the gastric cancer cells.

Conclusions:

Knockdown of the expression of nuclear receptor coactivator 2 can inhibit the proliferation and invasion of human gastric cancer in vitro and in vivo. The underlying mechanism of NOCA2 affects the Wnt signaling pathway.

Mutations and mechanisms of WNT pathway tumour suppressors in cancer

Mutation-induced activation of WNT-β-catenin signalling is a frequent driver event in human cancer. Sustained WNT-β-catenin pathway activation endows cancer cells with sustained self-renewing growth properties and is associated with therapy resistance. In healthy adult stem cells, WNT pathway activity is carefully controlled by core pathway tumour suppressors as well as negative feedback regulators. Gene inactivation experiments in mouse models unequivocally demonstrated the relevance of WNT tumour suppressor loss-of-function mutations for cancer growth. However, in human cancer, a far more complex picture has emerged in which missense or truncating mutations mediate stable expression of mutant proteins, with distinct functional and phenotypic ramifications. Herein, we review recent advances and challenges in our understanding of how different mutational subsets of WNT tumour suppressor genes link to distinct cancer types, clinical outcomes and treatment strategies.

Signaling pathways in hepatocellular carcinoma

Despite the recent introduction of new effective systemic agents, the survival of patients with hepatocellular carcinoma (HCC) at advanced stages remains dismal. This underscores the need for new therapies, which has spurred extensive research on the identification of the main drivers of pathway de-regulation as a source of novel therapeutic targets. Frequently altered pathways in HCC involve growth factor receptors (e.g., VEGFR, FGFR, TGFA, EGFR, IGFR) and/or its cytoplasmic intermediates (e.g., PI3K-AKT-mTOR, RAF/ERK/MAPK) as well as key pathways in cell differentiation (e.g., Wnt/β-catenin, JAK/STAT, Hippo, Hedgehog, Notch). Somatic mutations, chromosomal aberrations and epigenetic changes are common mechanisms for pathway deregulation in HCC. Aberrant pathway activation has also been explored as a biomarker to predict response to specific therapies, but currently, these strategies are not implemented when deciding systemic therapies in HCC patients. Beyond the well-established molecular cascades, there are numerous emerging signaling pathways also deregulated in HCC (e.g., tumor microenvironment, non-coding RNA, intestinal microbiota), which have opened new avenues for therapeutic exploration.

Wnt Pathway: An Integral Hub for Developmental and Oncogenic Signaling Networks

The Wnt pathway is an integral cell-to-cell signaling hub which regulates crucial development processes and maintenance of tissue homeostasis by coordinating cell proliferation, differentiation, cell polarity, cell movement, and stem cell renewal. When dysregulated, it is associated with various developmental diseases, fibrosis, and tumorigenesis. We now better appreciate the complexity and crosstalk of the Wnt pathway with other signaling cascades. Emerging roles of the Wnt signaling in the cancer stem cell niche and drug resistance have led to development of therapeutics specifically targeting various Wnt components, with some agents currently in clinical trials. This review highlights historical and recent findings on key mediators of Wnt signaling and how they impact antitumor immunity and maintenance of cancer stem cells. This review also examines current therapeutics being developed that modulate Wnt signaling in cancer and discusses potential shortcomings associated with available therapeutics.

Interplay Between Ion Channels and the Wnt/β-Catenin Signaling Pathway in Cancers

Increasing evidence point out the important roles of ion channels in the physiopathology of cancers, so that these proteins are now considered as potential new therapeutic targets and biomarkers in this disease. Indeed, ion channels have been largely described to participate in many hallmarks of cancers such as migration, invasion, proliferation, angiogenesis, and resistance to apoptosis. At the molecular level, the development of cancers is characterised by alterations in transduction pathways that control cell behaviors. However, the interactions between ion channels and cancer-related signaling pathways are poorly understood so far. Nevertheless, a limited number of reports have recently addressed this important issue, especially regarding the interaction between ion channels and one of the main driving forces for cancer development: the Wnt/β-catenin signaling pathway. In this review, we propose to explore and discuss the current knowledge regarding the interplay between ion channels and the Wnt/β-catenin signaling pathway in cancers.

Transgenic zebrafish for modeling hepatocellular carcinoma

Liver cancer is the third leading cause of cancer‐related deaths throughout the world, and more than 0.6 million people die from liver cancer annually. Therefore, novel therapeutic strategies to eliminate malignant cells from liver cancer patients are urgently needed. Recent advances in high‐throughput genomic technologies have identified de novo candidates for oncogenes and pharmacological targets. However, testing and understanding the mechanism of oncogenic transformation as well as probing the kinetics and therapeutic responses of spontaneous tumors in an intact microenvironment require in vivo examination using genetically modified animal models. The zebrafish (Danio rerio) has attracted increasing attention as a new model for studying cancer biology since the organs in the model are strikingly similar to human organs and the model can be genetically modified in a short time and at a low cost. This review summarizes the current knowledge of epidemiological data and genetic alterations in hepatocellular carcinoma (HCC), zebrafish models of HCC, and potential therapeutic strategies for targeting HCC based on knowledge from the models.

IMU1003, an atrarate derivative, inhibits Wnt/β-catenin signaling

Aberrant activation of the canonical Wnt/β-catenin signaling pathway triggers tumorigenesis in various tissues. This study identified an atrarate compound, IMU14, derived from filamentous fungi as an inhibitor of Wnt/β-catenin signaling in phenotypic chemical inhibitor screening of the zebrafish eyeless phenotype. Its derivatization resulted in synthesis of IMU1003 with enhanced Wnt inhibitory activity. IMU1003 inhibited β-catenin/TCF-dependent transcriptional activation and decreased nuclear β-catenin level. In addition, IMU1003 selectively decreased viability and target gene products of the Wnt/β-catenin signaling pathway in human non-colorectal cancer cell lines harboring intact APC and β-catenin. Therefore, atrarate derivatives inhibit Wnt/β-catenin signaling and show anticancer potential, and we developed a new class of chemical backbones for Wnt/β-catenin signaling inhibitors.

GSK3 Inhibits Macropinocytosis and Lysosomal Activity through the Wnt Destruction Complex Machinery

Canonical Wnt signaling is emerging as a major regulator of endocytosis. Here, we report that Wnt-induced macropinocytosis is regulated through glycogen synthase kinase 3 (GSK3) and the β-catenin destruction complex. We find that mutation of Axin1, a tumor suppressor and component of the destruction complex, results in the activation of macropinocytosis. Surprisingly, inhibition of GSK3 by lithium chloride (LiCl), CHIR99021, or dominant-negative GSK3 triggers macropinocytosis. GSK3 inhibition causes a rapid increase in acidic endolysosomes that is independent of new protein synthesis. GSK3 inhibition or Axin1 mutation increases lysosomal activity, which can be followed with tracers of active cathepsin D, β-glucosidase, and ovalbumin degradation. Microinjection of LiCl into the blastula cavity of Xenopus embryos causes a striking increase in dextran macropinocytosis. The effects of GSK3 inhibition on protein degradation in endolysosomes are blocked by the macropinocytosis inhibitors EIPA or IPA-3, suggesting that increases in membrane trafficking drive lysosomal activity.

Whole exome profiling and mutational analysis of Ocular Surface Squamous Neoplasia

PURPOSE

To determine genetic mutational profiles in patients with Ocular Surface Squamous Neoplasia (OSSN) using whole exome sequencing.

METHODS

Prospective, case-series study. Patient recruitment was conducted in a single tertiary referral center from April to September 2017. Specimens were obtained by incisional biopsies of tumors from ten eyes with histopathologic confirmation of OSSN. DNA whole exome sequencing and mutation analysis were performed.

RESULTS

Ten patients with clinically-diagnosed OSSN underwent DNA whole exome sequencing analysis. Deleterious mutations in 305 genes known to drive tumor development and progression were found. These mutations centered around two main pathways: DNA repair/cell cycle and development/growth. All ten samples had at least one mutation in a DNA repair/cell cycle gene and all but one sample had one in a development/growth gene. The most common mutation was found in TP53 and HGF (both present in 50% of cases) and mutually exclusive mutations were found in BRCA1 and BRCA2 (50% of cases). Mutations in APC, MSH6, PDGFRA, and PTCH1 were found in 40% of cases. Global mutation analysis identified ultraviolet induced radiation as the only mutational signature present in the dataset.

CONCLUSIONS

Mutations found in samples from patients with OSSN are mainly induced by ultraviolet radiation and occur within two main pathways related to DNA repair/cell cycle and development/growth. There are many clinically available drugs and several others being evaluated in clinical trials that target the genes found mutated in this study, offering new therapeutic options for OSSN.

Wnt/β-Catenin Signaling in Oral Carcinogenesis

Oral carcinogenesis is a complex and multifactorial process that involves cumulative genetic and molecular alterations, leading to uncontrolled cell proliferation, impaired DNA repair and defective cell death. At the early stages, the onset of potentially malignant lesions in the oral mucosa, or oral dysplasia, is associated with higher rates of malignant progression towards carcinoma in situ and invasive carcinoma. Efforts have been made to get insights about signaling pathways that are deregulated in oral dysplasia, as these could be translated into novel markers and might represent promising therapeutic targets. In this context, recent evidence underscored the relevance of the Wnt/β-catenin signaling pathway in oral dysplasia, as this pathway is progressively "switched on" through the different grades of dysplasia (mild, moderate and severe dysplasia), with the consequent nuclear translocation of β-catenin and expression of target genes associated with the maintenance of representative traits of oral dysplasia, namely cell proliferation and viability. Intriguingly, recent studies provide an unanticipated connection between active β-catenin signaling and deregulated endosome trafficking in oral dysplasia, highlighting the relevance of endocytic components in oral carcinogenesis. This review summarizes evidence about the role of the Wnt/β-catenin signaling pathway and the underlying mechanisms that account for its aberrant activation in oral carcinogenesis.

The Scaffold Protein Axin Promotes Signaling Specificity within the Wnt Pathway by Suppressing Competing Kinase Reactions

Scaffold proteins are thought to promote signaling specificity by accelerating reactions between bound kinase and substrate proteins. To test the long-standing hypothesis that the scaffold protein Axin accelerates glycogen synthase kinase 3β (GSK3β)-mediated phosphorylation of β-catenin in the Wnt signaling network, we measured GSK3β reaction rates with multiple substrates in a minimal, biochemically reconstituted system. We observed an unexpectedly small, ∼2-fold Axin-mediated rate increase for the β-catenin reaction when measured in isolation. In contrast, when both β-catenin and non-Wnt pathway substrates are present, Axin accelerates the β-catenin reaction by preventing competition with alternative substrates. At high competitor concentrations, Axin produces >10-fold rate effects. Thus, while Axin alone does not markedly accelerate the β-catenin reaction, in physiological settings where multiple GSK3β substrates are present, Axin may promote signaling specificity by suppressing interactions with competing, non-Wnt pathway targets. This mechanism for scaffold-mediated control of competition enables a shared kinase to perform distinct functions in multiple signaling networks.

Allosteric inhibitor of β-catenin selectively targets oncogenic Wnt signaling in colon cancer

Abnormal regulation of β-catenin initiates an oncogenic program that serves as a main driver of many cancers. Albeit challenging, β-catenin is an attractive drug target due to its role in maintenance of cancer stem cells and potential to eliminate cancer relapse. We have identified C2, a novel β-catenin inhibitor, which is a small molecule that binds to a novel allosteric site on the surface of β-catenin. C2 selectively inhibits β-catenin, lowers its cellular load and significantly reduces viability of β-catenin-driven cancer cells. Through direct binding to β-catenin, C2 renders the target inactive that eventually activates proteasome system for its removal. Here we report a novel pharmacologic approach for selective inhibition of β-catenin via targeting a cryptic allosteric modulation site. Our findings may provide a new perspective for therapeutic targeting of β-catenin.

Molecular Characteristics of Biliary Tract and Primary Liver Tumors

With the recent decline in cost of high-throughput next-generation sequencing, detailed characterization of biliary tract and primary liver tumors continues to evolve. Recent studies have elucidated molecular signatures that reflect distinct pathways of carcinogenesis reflective of viral, parasitic, and toxin-related etiologic factors. With greater elucidation of the molecular pathogenesis of disease, novel targets that may be potential clinically actionable continue to be identified.

Inhibition of the Wnt/β-catenin pathway enhances antitumor immunity in ovarian cancer

Background:

The Wnt/β-catenin pathway is linked to tumorigenesis in a variety of tumors and promotes T cell exclusion and resistance to checkpoint inhibitors. We sought to determine whether a small molecule inhibitor of this pathway, WNT974, would impair tumor growth, affect gene expression patterns, and improve the immune response in human and murine ovarian cancer models.

Methods:

Human ovarian cancer cells were treated with WNT974 in vitro. RNAseq libraries were constructed and differences in gene expression patterns between responders and nonresponders were compared to The Cancer Genome Atlas (TCGA). Mice with subcutaneous or intraperitoneal ID8 ovarian cancer tumors were treated with WNT974, paclitaxel, combination, or control. Tumor growth and survival were measured. Flow cytometry and β-TCR repertoire analysis were used to determine the immune response.

Results:

Gene expression profiling revealed distinct signatures in responders and nonresponders, which strongly correlated with T cell infiltration patterns in the TCGA analysis of ovarian cancer. WNT974 inhibited tumor growth, prevented ascites formation, and prolonged survival in mouse models. WNT974 increased the ratio of CD8⁺ T cells to T regulatory cells (Tregs) in tumors and enhanced the effector functions of infiltrating CD4⁺ and CD8⁺ T cells. Treatment also decreased the expression of inhibitory receptors on CD8⁺ T cells. Combining WNT974 with paclitaxel further reduced tumor growth, prolonged survival, and expanded the T cell repertoire.

Conclusions:

These findings suggest that inhibiting the Wnt/β-catenin pathway may have a potent immunomodulatory effect in the treatment of ovarian cancer, particularly when combined with paclitaxel.

Biochemical and molecular aspects of 1,2-dimethylhydrazine (DMH)-induced colon carcinogenesis: a review

1,2-dimethylhydrazine (DMH) is a member in the class of hydrazines, strong DNA alkylating agent, naturally present in cycads. DMH is widely used as a carcinogen to induce colon cancer in animal models. Exploration of DMH-induced colon carcinogenesis in rodent models provides the knowledge to perceive the biochemical, molecular, and histological mechanisms of different stages of colon carcinogenesis. The procarcinogen DMH, after a series of metabolic reactions, finally reaches the colon, there produces the ultimate carcinogen and reactive oxygen species (ROS), which further alkylate the DNA and initiate the development of colon carcinogenesis. The preneolpastic lesions and histopathological observations of DMH-induced colon tumors may provide typical understanding about the disease in rodents and humans. In addition, this review discusses about the action of biotransformation and antioxidant enzymes involved in DMH intoxication. This understanding is essential to accurately identify and interpret alterations that occur in the colonic mucosa when evaluating natural or pharmacological compounds in DMH-induced animal colon carcinogenesis.

Inhibiting WNT Ligand Production for Improved Immune Recognition in the Ovarian Tumor Microenvironment

In ovarian cancer, upregulation of the Wnt/β–catenin pathway leads to chemoresistance and correlates with T cell exclusion from the tumor microenvironment (TME). Our objectives were to validate these findings in an independent cohort of ovarian cancer subjects and determine whether inhibiting the Wnt pathway in a syngeneic ovarian cancer murine model could create a more T-cell-inflamed TME, which would lead to decreased tumor growth and improved survival. We preformed RNA sequencing in a cohort of human high grade serous ovarian carcinoma subjects. We used CGX1321, an inhibitor to the porcupine (PORCN) enzyme that is necessary for secretion of WNT ligand, in mice with established ID8 tumors, a murine ovarian cancer cell line. In order to investigate the effect of decreased Wnt/β–catenin pathway activity in the dendritic cells (DCs), we injected ID8 cells in mice that lacked β–catenin specifically in DCs. Furthermore, to understand how much the effects of blocking the Wnt/β–catenin pathway are dependent on CD8⁺ T cells, we injected ID8 cells into mice with CD8⁺ T cell depletion. We confirmed a negative correlation between Wnt activity and T cell signature in our cohort. Decreasing WNT ligand production resulted in increases in T cell, macrophage and dendritic cell functions, decreased tumor burden and improved survival. Reduced tumor growth was found in mice that lacked β–catenin specifically in DCs. When CD8⁺ T cells were depleted, CGX1321 treatment did not have the same magnitude of effect on tumor growth. Our investigation confirmed an increase in Wnt activity correlated with a decreased T-cell-inflamed environment; a relationship that was further supported in our pre-clinical model that suggests inhibiting the Wnt/β–catenin pathway was associated with decreased tumor growth and improved survival via a partial dependence on CD8⁺ T cells.

WNT and β-Catenin in Cancer: Genes and Therapy

The WNT pathway is a pleiotropic signaling pathway that controls developmental processes, tissue homeostasis, and cancer. The WNT pathway is commonly mutated in many cancers, leading to widespread research into the role of WNT signaling in carcinogenesis. Understanding which cancers are reliant upon WNT activation and which components of the WNT signaling pathway are mutated is paramount to advancing therapeutic strategies. In addition, building holistic insights into the role of WNT signaling in not only tumor cells but also the tumor microenvironment is a vital area of research and may be a promising therapeutic strategy in multiple immunologically inert cancers. Novel compounds aimed at modulating the WNT signaling pathway using diverse mechanisms are currently under investigation in preclinical/early clinical studies. Here, we review how the WNT pathway is activated in multiple cancers and discuss current strategies to target aberrant WNT signaling.

Complex Interplay between the RUNX Transcription Factors and Wnt/β-Catenin Pathway in Cancer: A Tango in the Night

Cells are designed to be sensitive to a myriad of external cues so they can fulfil their individual destiny as part of the greater whole. A number of well-characterised signalling pathways dictate the cell's response to the external environment and incoming messages. In healthy, well-ordered homeostatic systems these signals are tightly controlled and kept in balance. However, given their powerful control over cell fate, these pathways, and the transcriptional machinery they orchestrate, are frequently hijacked during the development of neoplastic disease. A prime example is the Wnt signalling pathway that can be modulated by a variety of ligands and inhibitors, ultimately exerting its effects through the β-catenin transcription factor and its downstream target genes. Here we focus on the interplay between the three-member family of RUNX transcription factors with the Wnt pathway and how together they can influence cell behaviour and contribute to cancer development. In a recurring theme with other signalling systems, the RUNX genes and the Wnt pathway appear to operate within a series of feedback loops. RUNX genes are capable of directly and indirectly regulating different elements of the Wnt pathway to either strengthen or inhibit the signal. Equally, β-catenin and its transcriptional co-factors can control RUNX gene expression and together they can collaborate to regulate a large number of third party co-target genes.

ROR-α-1 inhibits the proliferation, invasion, and migration of hepatocellular carcinoma MHCC97H via downregulation of chemokine CXCL5

Hepatocarcinogenesis is a complicated process that is affected by a variety of microenvironmental factors, such as secretory chemokines and cell-extracellular matrix (ECM). Retinoic acid receptor-related orphan receptor (ROR)-α has been shown to attenuate tumor invasiveness by inducing suppressive cell microenvironment, and its low expression was associated with a worse prognosis in HCC patients. In the present study, we attempted to investigate the role and mechanism of the dominant transcript of ROR-α, ROR-α-1, in HCC development and progression. Among the four transcripts (ROR-α-1/-2/-3/-4), overexpression of ROR-α-1 dramatically suppressed the capacity of MHCC97H cells to proliferate, migrate and invade. We analyzed the differentially expressed genes in ROR-α-1-overexpressed and non-overexpressed MHCC97H cells, performed Gene Ontology (GO) enrichment analysis on these differentially-expressed genes, and found out that factors involved in the tumor microenvironment and ECM are related to the anti-tumor effects of ROR-α-1. Among these factors, chemokine CXCL5 was significantly downregulated by ROR-α-1 overexpression. Overexpression of ROR-α-1 remarkably inhibited the capacity of HCC cells to proliferate, migrate, invade, and downregulated the protein levels of β-catenin, c-Myc, Cyclin D1, and N-cadherin, suggesting the tumor-suppressive role of ROR-α-1 in MHCC97H cells. Moreover, overexpression of CXCL5 dramatically attenuated the suppressive effects of cell proliferation, migration and invasion induced by ROR-α-1 overexpression in MHCC97H, suggesting that ROR-α-1 exerts its anti-tumor effects via downregulating CXCL5. In conclusion, we demonstrate the tumor-suppressive role of ROR-α-1 in MHCC97H cells and that ROR-α-1 might play a tumor-suppressive role via regulation of chemokine CXCL5.

Wnt Signaling: Paths for Cancer Progression

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

Axin Family of Scaffolding Proteins in Development: Lessons from C. elegans

Scaffold proteins serve important roles in cellular signaling by integrating inputs from multiple signaling molecules to regulate downstream effectors that, in turn, carry out specific biological functions. One such protein, Axin, represents a major evolutionarily conserved scaffold protein in metazoans that participates in the WNT pathway and other pathways to regulate diverse cellular processes. This review summarizes the vast amount of literature on the regulation and functions of the Axin family of genes in eukaryotes, with a specific focus on Caenorhabditis elegans development. By combining early studies with recent findings, the review is aimed to serve as an updated reference for the roles of Axin in C. elegans and other model systems.

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.

Identifying Hepatocellular Carcinoma Driver Genes by Integrative Pathway Crosstalk and Protein Interaction Network

In this study, we mined out hepatocellular carcinoma (HCC) driver genes from MEDLINE literatures by bioinformatics methods of pathway crosstalk and protein interaction network. Furthermore, the relationship between driver genes and their clinicopathological characteristics, as well as classification effectiveness was verified in the public databases. We identified 560 human genes reported to be associated with HCC in 1074 published articles. Functional analysis revealed that biological processes and biochemical pathways relating to tumor pathogenesis, cancer disease, tumor cell molecule, and hepatic disease were enriched in these genes. Pathway crosstalk analysis indicated that significant pathways could be divided into three modules: cancer disease, virus infection, and tumor signaling pathway. The HCC-related protein-protein interaction network comprised 10,212 nodes, and 56,400 edges were mined out to identify 18 modules corresponding to 14 driver genes. We verified that these 14 driver genes have high classification effectiveness to distinguish cancer samples from normal samples and the classification effectiveness was better than that of randomly selected genes. Present study provided pathway crosstalk and protein interaction network for understanding potential tumorigenesis genes underlying HCC. The 14 driver genes identified from this study are of great translational value in HCC diagnosis and treatment, as well as in clinical study on the pathogenesis of HCC.

The Mutational Landscape of Pancreatic and Liver Cancers, as Represented by Circulating Tumor DNA

The mutational landscapes of pancreatic and liver cancers share many common genetic alterations which drive cancer progression. However, these mutations do not occur in all cases of these diseases, and this tumoral heterogeneity impedes diagnosis, prognosis, and therapeutic development. One minimally invasive method for the evaluation of tumor mutations is the analysis of circulating tumor DNA (ctDNA), released through apoptosis, necrosis, and active secretion by tumor cells into various body fluids. By observing mutations in those genes which promote transformation by controlling the cell cycle and oncogenic signaling pathways, a representation of the mutational profile of the tumor is revealed. The analysis of ctDNA is a promising technique for investigating these two gastrointestinal cancers, as many studies have reported on the accuracy of ctDNA assessment for diagnosis and prognosis using a variety of techniques.

Recombinant porcine NK-lysin inhibits the invasion of hepatocellular carcinoma cells in vitro

The therapeutics having ability to target cancer cells specifically and exhibit nominal cytopathic effect on normal healthy cells are highly significant for cancer therapeutic applications. Recombinant porcine natural killer lysin (rpNK-lysin) has proven cationic anti-bacterial and anti-tumor peptide. Herein, we report its anti-invasion and anti-metastasis effects on hepatocellular carcinoma (HCC) cells in vitro. We first investigate the maximum non-toxic concentration (MNTC) of rpNK-lysin for the normal hepato cells (L-02). Using MNTC rpNK-lysin, we explore anti-proliferative, anti-adhesive, anti-invasive and anti-metastatic effect of rpNK-lysin on three different HCC cells lines (SMMC-7721, 97-H and HepG2) through MTT, wound-healing, adhesion and invasion assay along with mRNA and protein expression. The results reveal that rpNK-lysin has potential to specifically inhibit HCC cells growth in a dose and time-dependent manner with a little cytopathic effect on the L-02 cells, effectively reduce migration, adhesion and invasion ability of HCC cells. rpNK-lysin significantly reduce Fascin1 expression, which subsequently decrease β-catenin expression and metaloproteinases (MMP-2 and MMP9). This study suggest that MNTC rpNK-lysin has an anti-invasion and anti-metastasis effect on HCC cells in vitro through inhibition of Fascin 1 expression which regulates Wnt/β-catenin signaling pathway by inducing β-catenin degradation and subsequently results in suppression of MMP-2 and MMP9 expression.

A Role for the WNT Co-Receptor LRP6 in Pathogenesis and Therapy of Epithelial Cancers

The WNT/β-catenin signaling pathway controls stem and progenitor cell proliferation, survival and differentiation in epithelial tissues. Aberrant stimulation of this pathway is therefore frequently observed in cancers from epithelial origin. For instance, colorectal and hepatic cancers display activating mutations in the CTNNB1 gene encoding β-catenin, or inactivating APC and AXIN gene mutations. However, these mutations are uncommon in breast and pancreatic cancers despite nuclear β-catenin localization, indicative of pathway activation. Notably, the low-density lipoprotein receptor-related protein 6 (LRP6), an indispensable co-receptor for WNT, is frequently overexpressed in colorectal, liver, breast and pancreatic adenocarcinomas in association with increased WNT/β -catenin signaling. Moreover, LRP6 is hyperphosphorylated in KRAS-mutated cells and in patient-derived colorectal tumours. Polymorphisms in the LRP6 gene are also associated with different susceptibility to developing specific types of lung, bladder and colorectal cancers. Additionally, recent observations suggest that LRP6 dysfunction may be involved in carcinogenesis. Indeed, reducing LRP6 expression and/or activity inhibits cancer cell proliferation and delays tumour growth in vivo. This review summarizes current knowledge regarding the biological function and regulation of LRP6 in the development of epithelial cancers—especially colorectal, liver, breast and pancreatic cancers.