Dysregulation Of Wnt Pathway Research Articles

MAML3-fusions modulate vascular and immune tumour microenvironment and confer high metastatic risk in pheochromocytoma and paraganglioma

Pheochromocytomas and paragangliomas are rare neuroendocrine tumours. Around 20-25% of patients develop metastases, for which there is an urgent need of prognostic markers and therapeutic stratification strategies. The presence of a MAML3-fusion is associated with increased metastatic risk, but neither the processes underlying disease progression, nor targetable vulnerabilities have been addressed. We have compiled a cohort of 850 patients, which has shown a 3.65% fusion prevalence and represents the largest MAML3-positive series reported to date. While MAML3-fusions mainly cause single pheochromocytomas, we also observed somatic post-zygotic events, resulting in multiple tumours in the same patient. MAML3-tumours show increased expression of neuroendocrine-to-mesenchymal transition markers, MYC-targets, and angiogenesis-related genes, leading to a distinct tumour microenvironment with unique vascular and immune profiles. Importantly, our findings have identified MAML3-tumours specific vulnerabilities beyond Wnt-pathway dysregulation, such as a rich vascular network, and overexpression of PD-L1 and CD40, suggesting potential therapeutic targets.

Developmental toxicity assay of xanthatin in zebrafish embryos

Xanthatin (XAN), a xanthanolide sesquiterpene lactone, isolated from Chinese herb, Xanthium strumarium L, has various pharmacological activities, such as antitumor activity and anti-inflammatory. However, little is known about its potential toxicity and the mechanism. Here, zebrafish model was used to study the developmental toxicity in vivo. Our results indicated that xanthatin increased the mortality and led to the morphological abnormalities including pericardial edema, yolk sac edema, curved body shape and hatching delay. Furthermore, xanthatin damaged the normal structure and/or function of heart, liver, immune and nervous system. ROS elevation and much more apoptosis cells were observed after xanthatin exposure. Gene expression results showed that oxidative stress-related genes nrf2 was inhibited, while oxidative stress-related genes (keap1 and nqo1) and apoptotic genes (caspase3, caspase9 and p53) were increased after xanthatin exposure. Mitophagy related genes pink1 and parkin, and wnt pathway (β-catenin, wnt8a and wnt11) were significantly increased after xanthatin exposure. Taken together, our finding indicated that xanthatin induced developmental toxicity, and the ROS elevation, apoptosis activation, dysregulation of mitophagy and wnt pathways were involved in the toxicity caused by xanthatin.

Investigating the association of WNT pathway dysregulation and young-onset colorectal cancer.

217 Background: Colorectal cancer (CRC) is the third most common cancer in the United States with studies showing increasing incidence of Young-Onset CRC, defined as cases occurring in individuals 50 years old or younger. Separately, the WNT Signaling Pathway and its subsequent mutation can result in sustained activation and, therefore, unregulated cell proliferation which has been well described in colorectal cancers. Loss of function in APC, AXIN1, AXIN2, GKS3B, and RNF43 can each act to dysregulate WNT signaling, contributing to cancer development. In this study, we aimed to conduct a comprehensive, molecular evaluation of the WNT signaling pathway in colorectal cancer within age-specific cohorts with onset of CRC at 50 years old or less versus greater than 50 years old. Methods: We used published individual patient-level data of 6286 patients with colorectal cancer (CRC) from the 16 CRC datasets included in the cbioportal database. The WNT pathway alterations, including APC, AXIN1, AXIN2, GKS3B and RNF43 mutations were considered to define the WNT mutant CRC cohort. The presence of WNT alterations according to the age (50 years old or younger vs. over 50 years) were evaluated using Chi-square tests. The association between primary tumor distribution (colon vs. rectal) and age were evaluated across patients with and without WNT pathway alterations. The effect of WNT pathway alterations on the overall survival and survival after the metastatic stage was evaluated with Kaplan-Meier survival curves. A type-I error level of 5% (p<0.05) was considered the threshold limit for statistical significance. Results: A total of 2,630 individuals were identified with relevant clinical and molecular information. When comparing WNT alteration patterns between young-onset CRC (< 50 years old) and CRC in cohort >50 years old, there was no statistically significant difference (p-value .215). Analysis of common individual mutations in APC, AXIN1, AXIN2, GKS3B and RNF43 also showed similar incidences across age groups. However, we identified WNT alterations were significantly more common in rectal cancers compared to colon cancer, being found in 75.9% of rectal cancer cases, regardless of age groups (p-value <0.00001). Additionally, individuals identified to have WNT alterations were found to have improved survival with a median overall survival of of 58.19 months versus a median of 41.72 months in those without. Conclusions: Overall, no significant differences were found in WNT alteration expression between Young-onset CRC versus CRC in individuals over the age of 50. However, across all age groups, WNT alterations were frequently found in rectal cancers. Furthermore, these WNT alterations were associated with better outcomes.

Lesser prevalence of polyps/WNT-dysregulation and concomitant upregulation of gamma-catenin/MYC point to alternate pathways in colorectal cancer in India.

Colorectal cancer (CRC) is known to follow adenoma carcinoma sequence (ACS) in majority of the tumors and the driver variants and associated pathways are well delineated. However, most of the published data are from the west and information in other ethnicities is sparse. We therefore comprehensively evaluated the CRC tumors from Indian ethnicity for the prevalence of ACS. In this cohort study, clinical data of 100,497 patients who attended hospital between 2013 and 2018 were accessed. Tumors from patients (n = 130) with CRC who were treated primarily by surgery were included. DNA and RNA were isolated to assess variants (direct sequencing) and WNT-pathway dysregulation in genes related to ACS. Global gene expression was generated and analyzed on microarrays (Affymetrix; N = 10) and next generation sequencing platforms (Illumina; N = 25). Gene expression at mRNA (qRT-PCR) and protein level (IHC) of JUP/CTNNB1/MYC were assessed. Correlation between expression of JUP and MYC was evaluated by Karl Pearson's correlation coefficient. The prevalence of polyps was 16.75%, while 18.26% variants in APC/CTNNB1, 20.00% in KRAS, and 18.33% WNT dysregulation were noted. Interestingly, 29/60 (48.33%) tumors showed only MYC upregulation with normal APC/CTNNB1 expression. Global gene expression and validation in an independent tumor cohort confirmed concomitant upregulation of JUP (gamma-catenin) & MYC (r = 0.71; p = 0.001) at mRNA and protein in sizeable number of tumors (45/96; 46.88%). Our study provides evidence for limited prevalence of ACSin the Indian ethnicity. Preventive colonoscopies for early identification and management of CRC may not be an effective strategy in this ethnicity.

ROR1-STAT3 signaling contributes to ovarian cancer intra-tumor heterogeneity

Wnt pathway dysregulation through genetic and non-genetic alterations occurs in multiple cancers, including ovarian cancer (OC). The aberrant expression of the non-canonical Wnt signaling receptor ROR1 is thought to contribute to OC progression and drug resistance. However, the key molecular events mediated by ROR1 that are involved in OC tumorigenesis are not fully understood. Here, we show that ROR1 expression is enhanced by neoadjuvant chemotherapy, and Wnt5a binding to ROR1 can induce oncogenic signaling via AKT/ERK/STAT3 activation in OC cells. Proteomics analysis of isogenic ROR1-knockdown OC cells identified STAT3 as a downstream effector of ROR1 signaling. Transcriptomics analysis of clinical samples (n = 125) revealed that ROR1 and STAT3 are expressed at higher levels in stromal cells than in epithelial cancer cells of OC tumors, and these findings were corroborated by multiplex immunohistochemistry (mIHC) analysis of an independent OC cohort (n = 11). Our results show that ROR1 and its downstream STAT3 are co-expressed in epithelial as well as stromal cells of OC tumors, including cancer-associated fibroblasts or CAFs. Our data provides the framework to expand the clinical utility of ROR1 as a therapeutic target to overcome OC progression.

The Wnt Pathway Inhibitor RXC004 Blocks Tumor Growth and Reverses Immune Evasion in Wnt Ligand-dependent Cancer Models.

Wnt pathway dysregulation drives many gastrointestinal cancers; however, there are no approved therapies that target the pathway. RXC004 has demonstrated the potential to block both tumor growth and tumor immune evasion in a genetically defined, clinically actionable subpopulation of Wnt ligand-dependent gastrointestinal cancers. The clinical utility of RXC004, and other Porcupine inhibitors, in such Wnt ligand-dependent cancers is currently being assessed in patient trials.

Genetic and Epigenetic Characteristics of Inflammatory Bowel Disease–Associated Colorectal Cancer

Inflammatory bowel disease (IBD) is a chronic, relapsing inflammatory disorder associated with an elevated risk of colorectal cancer (CRC). IBD-associated CRC (IBD-CRC) may represent a distinct pathway of tumorigenesis compared to sporadic CRC (sCRC). Our aim was to comprehensively characterize IBD-associated tumorigenesis integrating multiple high-throughput approaches, and to compare the results with in-house data sets from sCRCs. Whole-genome sequencing, single nucleotide polymorphism arrays, RNA sequencing, genome-wide methylation analysis, and immunohistochemistry were performed using fresh-frozen and formalin-fixed tissue samples of tumor and corresponding normal tissues from 31 patients with IBD-CRC. Transcriptome-based tumor subtyping revealed the complete absence of canonical epithelial tumor subtype associated with WNT signaling in IBD-CRCs, dominated instead by mesenchymal stroma-rich subtype. Negative WNT regulators AXIN2 and RNF43 were strongly down-regulated in IBD-CRCs and chromosomal gains at HNF4A, a negative regulator of WNT-induced epithelial-mesenchymal transition (EMT), were less frequent compared to sCRCs. Enrichment of hypomethylation at HNF4α binding sites was detected solely in sCRC genomes. PIGR and OSMR involved in mucosal immunity were dysregulated via epigenetic modifications in IBD-CRCs. Genome-wide analysis showed significant enrichment of noncoding mutations to 5'untranslated region of TP53 in IBD-CRCs. As reported previously, somatic mutations in APC and KRAS were less frequent in IBD-CRCs compared to sCRCs. Distinct mechanisms of WNT pathway dysregulation skew IBD-CRCs toward mesenchymal tumor subtype, which may affect prognosis and treatment options. Increased OSMR signaling may favor the establishment of mesenchymal tumors in patients with IBD.

Embryonic Expression of NrasG 12 D Leads to Embryonic Lethality and Cardiac Defects.

Ras proteins control a complex intracellular signaling network. Gain-of-function mutations in RAS genes lead to RASopathy disorders in humans, including Noonan syndrome (NS). NS is the second most common syndromic cause of congenital heart disease. Although conditional expression of the NrasG12D/+ mutation in adult hematopoietic system is leukemogenic, its effects on embryonic development remain unclear. Here, we report that pan-embryonic expression of endogenous NrasG12D/+ by Mox2-Cre in mice caused embryonic lethality from embryonic day (E) 15.5 and developmental defects predominantly in the heart. At E13.5, NrasG12D/+; Mox2Cre/+ embryos displayed a moderate expansion of hematopoietic stem and progenitor cells without a significant impact on erythroid differentiation in the fetal liver. Importantly, the mutant embryos exhibited cardiac malformations resembling human congenital cardiac defects seen in NS patients, including ventricular septal defects, double outlet right ventricle, the hypertrabeculation/thin myocardium, and pulmonary valve stenosis. The mutant heart showed dysregulation of ERK, BMP, and Wnt pathways, crucial signaling pathways for cardiac development. Endothelial/endocardial-specific expression of NrasG12D/+ caused the cardiac morphological defects and embryonic lethality as observed in NrasG12D/+; Mox2Cre/+ mutants, but myocardial-specific expression of NrasG12D/+ did not. Thus, oncogenic NrasG12D mutation may not be compatible with embryonic survival.

The multiple ways Wnt signaling contributes to acute leukemia pathogenesis.

WNT proteins constitute a very conserved family of secreted glycoproteins that act as short-range ligands for signaling with critical roles in hematopoiesis, embryonic development, and tissue homeostasis. These proteins transduce signals via the canonical pathway, which is β-catenin-mediated and better-characterized, or via more diverse noncanonical pathways that are β-catenin independent and comprise the planar cell polarity (PCP) pathway and the WNT/Ca++ pathways. Several proteins regulate Wnt signaling through a variety of sophisticated mechanisms. Disorders within the pathway can contribute to various human diseases, and the dysregulation of Wnt pathways by different molecular mechanisms is implicated in the pathogenesis of many types of cancer, including the hematological malignancies. The types of leukemia differ considerably and can be subdivided into chronic, myeloid or lymphocytic, and acute, myeloid or lymphocytic, leukemia, according to the differentiation stage of the predominant cells, the progenitor lineage, the diagnostic age strata, and the specific molecular drivers behind their development. Here, we review the role of Wnt signaling in normal hematopoiesis and discuss in detail the multiple ways canonical Wnt signaling can be dysregulated in acute leukemia, including alterations in gene expression and protein levels, epigenetic regulation, and mutations. Furthermore, we highlight the different impacts of these alterations, considering the distinct forms of the disease, and the therapeutic potential of targeting Wnt signaling.

Targeting Wnt Signaling for the Treatment of Gastric Cancer.

The Wnt signaling pathway is evolutionarily conserved, regulating both embryonic development and maintaining adult tissue homeostasis. Wnt signaling controls several fundamental cell functions, including proliferation, differentiation, migration, and stemness. It therefore plays an important role in the epithelial homeostasis and regeneration of the gastrointestinal tract. Often, both hypo- or hyper-activation of the pathway due to genetic, epigenetic, or receptor/ligand alterations are seen in many solid cancers, such as breast, colorectal, gastric, and prostate. Gastric cancer (GC) is the fourth commonest cause of cancer worldwide and is the second leading cause of cancer-related death annually. Although the number of new diagnoses has declined over recent decades, prognosis remains poor, with only 15% surviving to five years. Geographical differences in clinicopathological features are also apparent, with epidemiological and genetic studies revealing GC to be a highly heterogeneous disease with phenotypic diversity as a result of etiological factors. The molecular heterogeneity associated with GC dictates that a single ‘one size fits all’ approach to management is unlikely to be successful. Wnt pathway dysregulation has been observed in approximately 50% of GC tumors and may offer a novel therapeutic target for patients who would otherwise have a poor outcome. This mini review will highlight some recent discoveries involving Wnt signaling in GC.

Microglia and Wnt Pathways: Prospects for Inflammation in Alzheimer's Disease.

Alzheimer’s disease (AD) has been a major health issue for more than one century since it was first reported in 1906. As one of the most common neurodegenerative diseases, AD is characterized by the presence of senile plaques and neurofibrillary tangles (NFTs) in the affected brain area. Microglia are the major regulators of neuroinflammation in the brain, and neuroinflammation has become recognized as the core pathophysiological process of various neurodegenerative diseases. In the central nervous system (CNS), microglia play a dual role in AD development. For one thing, they degrade amyloid β (Aβ) to resist its deposition; for another, microglia release pro-inflammatory and inflammatory factors, contributing to neuroinflammation as well as the spreading of Aβ and tau pathology. Wnt pathways are important regulators of cell fate and cell activities. The dysregulation of Wnt pathways is responsible for both abnormal tau phosphorylation and synaptic loss in AD. Recent studies have also confirmed the regulatory effect of Wnt signaling on microglial inflammation. Thus, the study of microglia, Wnt pathways, and their possible interactions may open up a new direction for understanding the mechanisms of neuroinflammation in AD. In this review, we summarize the functions of microglia and Wnt pathways and their roles in AD in order to provide new ideas for understanding the pathogenesis of AD.

Excessive β-Catenin in Excitatory Neurons Results in Reduced Social and Increased Repetitive Behaviors and Altered Expression of Multiple Genes Linked to Human Autism.

Multiple human autism risk genes are predicted to converge on the β-catenin (β-cat)/Wnt pathway. However, direct tests to link β-cat up- or down-regulation with autism are largely lacking, and the associated pathophysiological changes are poorly defined. Here we identify excessive β-cat as a risk factor that causes expression changes in several genes relevant to human autism. Our studies utilize mouse lines with β-cat dysregulation in forebrain excitatory neurons, identified as cell types with a convergent expression of autism-linked genes in both human and mouse brains. We show that mice expressing excessive β-cat display behavioral and molecular changes, including decreased social interest, increased repetitive behaviors, reduced parvalbumin and altered expression levels of additional genes identified as potential risk factors for human autism. These behavioral and molecular phenotypes are averted by reducing β-cat in neurons predisposed by gene mutations to express elevated β-cat. Using next-generation sequencing of the prefrontal cortex (PFC), we identify 87 dysregulated genes that are shared between mouse lines with excessive β-cat and autism-like behaviors, but not mouse lines with reduced β-cat and normal social behavior. Our findings provide critical new insights into β-cat, Wnt pathway dysregulation in the brain causing behavioral phenotypes relevant to the disease and the molecular etiology which includes several human autism risk genes.

Prevention of Colorectal Carcinogenesis by DNA-Binding Small-Molecule Curaxin CBL0137 Involves Suppression of Wnt Signaling.

Chemoprevention is considered a valid approach to reduce the incidence of colorectal cancer, one of the most common malignancies worldwide. Here, we investigated the tumor-preventive activity of curaxin CBL0137. This compound represents a new class of nonmutagenic DNA-binding small molecules that alter chromatin stability and inhibit the function of the histone chaperone FACT. Among downstream effects of CBL0137 treatment are activation of p53 and type I interferons and inhibition of NFκB, HSF1, and MYC. In addition, our data show that in both human and mouse colorectal cancer cells in vitro, CBL0137 inhibits the APC/WNT/β-catenin signaling pathway, which plays a key role in colon carcinogenesis. Using quantitative RT-PCR and microarray hybridization, we have demonstrated decreased expression of multiple components and downstream targets of the WNT pathway in colon cancer cells treated with CBL0137. At the same time, CBL0137 induced expression of WNT antagonists. Inhibition of WNT signaling activity by CBL0137 was also confirmed by luciferase reporter assay. Tumor-preventive activity of CBL0137 in vivo was tested in a murine model of colorectal carcinogenesis induced by 1,2-dimethylhydrazine (DMH), which is known to involve WNT pathway dysregulation. After DMH subcutaneous treatment, mice were administered CBL0137 in drinking water. Efficacy of CBL0137 in suppressing development of colorectal cancer in this model was evidenced by reduced incidence of adenocarcinomas and adenomas in both males and females and decrease in tumor multiplicity. These data support the prospective use of CBL0137 in chemoprevention of colorectal cancer as well as of other malignances associated with activated WNT signaling.

Neuronal network remodeling and Wnt pathway dysregulation in the intra-hippocampal kainate mouse model of temporal lobe epilepsy.

Mouse models of mesial temporal lobe epilepsy recapitulate aspects of human epilepsy, which is characterized by neuronal network remodeling in the hippocampal dentate gyrus. Observational studies suggest that this remodeling is associated with altered Wnt pathway signaling, although this has not been experimentally examined. We used the well-characterized mouse intrahippocampal kainate model of temporal lobe epilepsy to examine associations between hippocampal neurogenesis and altered Wnt signaling after seizure induction. Tissue was analyzed using immunohistochemistry and confocal microscopy, and gene expression analysis was performed by RT-qPCR on RNA extracted from anatomically micro-dissected dentate gyri. Seizures increased neurogenesis and dendritic arborization of newborn hippocampal dentate granule cells in peri-ictal regions, and decreased neurogenesis in the ictal zone, 2-weeks after kainate injection. Interestingly, administration of the novel canonical Wnt pathway inhibitor XAV939 daily for 2-weeks after kainate injection further increased dendritic arborization in peri-ictal regions after seizure, without an effect on baseline neurogenesis in control animals. Transcriptome analysis of dentate gyri demonstrated significant canonical Wnt gene dysregulation in kainate-injected mice across all regions for Wnt3, 5a and 9a. Intriguingly, certain Wnt genes demonstrated differential patterns of dysregulation between the ictal and peri-ictal zones, most notably Wnt5B, 7B and DKK-1. Together, these results demonstrate regional variation in Wnt pathway dysregulation early after seizure induction, and surprisingly, suggest that some Wnt-mediated effects might actually temper aberrant neurogenesis after seizures. The Wnt pathway may therefore provide suitable targets for novel therapies that prevent network remodeling and the development of epileptic foci in high-risk patients.

P3828Zebrafish models for arrhythmogenic cardiomyopathy type 8: a starting platform for exercise stress test and drug treatment

Abstract Background Arrhythmogenic Cardiomyopathy (AC) is an inherited heart disease characterized by progressive substitution of the myocardium with fibro-fatty tissue, leading to electrical instability and high risk of sudden death, particularly in young subjects and athletes. In recent years, our laboratory has produced zebrafish (zf) mutant lines modelling AC type 8, an AC form linked to mutations in the junctional protein Desmoplakin (Dsp). Mutations in the DSP gene have been identified in both dominant and recessive AC cases, characterized by left-dominant and biventricular forms of the disease. Sports medicine has highlighted that they are the most dangerous forms, being less easily identifiable by ECG. Purpose Taking advantage of our zf Dsp mutant lines, we aim to fully characterize the pathological phenotype, analyze the perturbation of cell communication pathways, evaluate the role of the physical exercise, and test the efficacy of candidate drugs. Methods Among our zf lines we have identified double mutant animals, bearing both zf dspa and dspb mutations in heterozygous condition, as the best model able to recapitulate the human AC phenotype. This model underwent physical stress tests in the presence/absence of candidate drug treatment. Phenotyping included heart rhythm measurement, gene expression analysis using Real Time PCR and signaling pathway transgenes, immune-histochemistry, whole-mount in situ hybridization, standard histology and ultrastructural TEM analysis. Results Preliminary results from mutant phenotyping indicate alterations in heart rate, sudden cardiac death, structural alterations of the myocardium associated with junctional disorganization and, in parallel, dysregulation of Wnt, Hippo and TGFbeta pathways. Specifically, Dsp mutant animals can range from an 8% decrease to a 14% increase of heart rhythm compared to the physiological range (120–140 beats per minute in zf larvae). At the adult stage, about 1% of the fish mutant population dies suddenly. The histological examination shows a 50% reduction of the myocardial cell mass, in parallel with a 50% decrease of Dsp signal, detected by TEM, associated with the so-called “pale desmosome” phenotype. Signaling dysregulation includes an 80% loss of Wnt/Beta-catenin, a 300% increase of TGFbeta and a 500% increase of Hippo/YAP-TAZ signaling in the cardiac tissue. Physical stress tests and pathway-directed drug treatment have clarified that these factors can modulate the pathological phenotype, as preliminarily evidenced by the rescue of Wnt signal decrease to normal levels through SB216763 treatment of Dsp-deficient individuals at rest. Conclusion Preliminary evidences corroborate the zf organism as a suitable model for AC cellular and molecular phenotyping, exploitable for the dissection of the genetic events leading to the onset and progression of the disease, and applicable to the analysis of chemical and mechanical modulators of AC-associated features. Acknowledgement/Funding Cariparo 2017 SHoCD; TRANSAC; CPDA133979/13; RP-2014-ehz745.06700394

Discrimination of low- and high-grade appendiceal mucinous neoplasms by targeted sequencing of cancer-related variants

DNA was obtained from matching micro-dissected, primary tumor cells, paired metastases, and peripheral blood mononuclear cells (germline) from patients with appendiceal mucinous neoplasms. We compared specimens from patient cohorts comprising low-grade adenomucinous neoplasm versus high-grade mucinous adenocarcinoma using a targeted, amplicon sequencing panel of 409 cancer related genes (Ion Torrent Comprehensive Cancer Panel, Thermo-Fisher, Waltham, MA). Copy number variants, single nucleotide variants and small insertions/deletions were identified using a multiplex algorithm pipeline (GATK, VarScan2, MuTect2, SIFT, SIFT-INDEL, PolyPhen-2, Provean). There were significantly more damaging variants in high-grade versus low-grade tumor cohorts. Both cohorts contained damaging, heterozygous germline variants (catenin β1; notch receptor 1 and 4) in pathways associated with cell-lineage specification (WNT, NOTCH). Damaging, somatic KRAS proto-oncogene, GTPase mutations were present in both cohorts, while somatic GNAS complex locus mutations were confined to low-grade neoplasms. Variants predominantly affected transcription factors, kinases, and stem cell signaling molecules in canonical pathways including epithelial to mesenchymal transition, stem cell pluripotency, p53, PTEN, and NF-қB signaling pathways. High-grade tumors demonstrated MYC proto-oncogene, bHLH transcription factor (MYC) and death domain associated protein (DAXX) amplification and damaging somatic variants in tumor protein p53 (TP53), likely to amplify an aggressive phenotype. Damaging APC, WNT signaling pathway regulator (APC) deletions were identified in metastatic tissue of both cohorts suggesting a role in invasive disease. Our data suggest that germline dysregulation of WNT and/or NOTCH pathways predisposes patients toward a secretory cell phenotype (i.e., goblet-like cells) upon acquisition of somatic KRAS mutations. Additional somatically acquired variants activating oncogenes MYC and DAXX and inhibiting the critical tumor suppressor, tumor protein TP53, were consistent with manifestation of a high-grade phenotype. These additional changes within the epithelial to mesenchymal transition signaling network (WNT, NOTCH, RAS/ERK/PI3K, PTEN, NF-қB), produce aggressive high-grade tumor characteristics by actively driving cells towards dedifferentiation, proliferation, and migration.

Pathogenic WDFY3 variants cause neurodevelopmental disorders and opposing effects on brain size.

The underpinnings of mild to moderate neurodevelopmental delay remain elusive, often leading to late diagnosis and interventions. Here, we present data on exome and genome sequencing as well as array analysis of 13 individuals that point to pathogenic, heterozygous, mostly de novo variants in WDFY3 (significant de novo enrichment P = 0.003) as a monogenic cause of mild and non-specific neurodevelopmental delay. Nine variants were protein-truncating and four missense. Overlapping symptoms included neurodevelopmental delay, intellectual disability, macrocephaly, and psychiatric disorders (autism spectrum disorders/attention deficit hyperactivity disorder). One proband presented with an opposing phenotype of microcephaly and the only missense-variant located in the PH-domain of WDFY3. Findings of this case are supported by previously published data, demonstrating that pathogenic PH-domain variants can lead to microcephaly via canonical Wnt-pathway upregulation. In a separate study, we reported that the autophagy scaffolding protein WDFY3 is required for cerebral cortical size regulation in mice, by controlling proper division of neural progenitors. Here, we show that proliferating cortical neural progenitors of human embryonic brains highly express WDFY3, further supporting a role for this molecule in the regulation of prenatal neurogenesis. We present data on Wnt-pathway dysregulation in Wdfy3-haploinsufficient mice, which display macrocephaly and deficits in motor coordination and associative learning, recapitulating the human phenotype. Consequently, we propose that in humans WDFY3 loss-of-function variants lead to macrocephaly via downregulation of the Wnt pathway. In summary, we present WDFY3 as a novel gene linked to mild to moderate neurodevelopmental delay and intellectual disability and conclude that variants putatively causing haploinsufficiency lead to macrocephaly, while an opposing pathomechanism due to variants in the PH-domain of WDFY3 leads to microcephaly.

The Rac1 splice form Rac1b favors mouse colonic mucosa regeneration and contributes to intestinal cancer progression.

We previously have identified the ectopic expression of Rac1b, an activated and novel splice variant of Rac1, in a subset of human colorectal adenocarcinomas, as well as in inflammatory bowel diseases and in colitis mouse model. Rac1b overexpression has been further evidenced in breast, pancreatic, thyroid, ovarian, and lung cancers. In this context, the aim of our study was to investigate the physiopathological implications of Rac1b in intestinal inflammation and carcinogenesis in vivo. The ectopic expression of Rac1b was induced in mouse intestinal epithelial cells after crossing Rosa26-LSL-Rac1b and villin-Cre mice. These animals were let to age or were challenged with dextran sulfate sodium (DSS) to induce experimental colitis, or either received azoxymethane (AOM)/DSS treatment, or were bred with ApcMin/+ or Il10-/- mice to trigger intestinal tumors. Rac1b ectopic expression increased the intestinal epithelial cell proliferation and migration, enhanced the production of reactive oxygen species, and promoted the Paneth cell lineage. Although Rac1b overexpression alone was not sufficient to drive intestinal neoplasia, it enhanced Apc-dependent intestinal tumorigenesis. In the context of Il10 knockout, the Rac1b transgene strengthened colonic inflammation due to induced intestinal mucosa permeability and promoted cecum and proximal colon carcinogenesis. In contrast, Rac1b alleviated carcinogen/acute inflammation-associated colon carcinogenesis (AOM/DSS). This resulted at least partly from the early mucosal repair after resolution of inflammation. Our data highlight the critical role of Rac1b in driving wound-healing after resolution of intestinal inflammation, and in cooperating with Wnt pathway dysregulation and chronic inflammation to promote intestinal carcinogenesis.

Delineating Potential Transcriptomic Association with Organochlorine Pesticides in the Etiology of Epithelial Ovarian Cancer.

Background:Recent studies have shown that there is an increased risk of Epithelial Ovarian Cancer (EOC) with Organochlorine Pesticides (OCPs). However, the alteration in the gene expression profile has not been explored so far. The goal of the present study is to understand the probable molecular mechanism of OCPs toxicity towards discovery of dysregulation of signaling pathway associated with differential gene expression and candidate transcriptomic set of markers in the pathophysiology of EOC in OCPs exposed population.Methods:The OCP levels were estimated by gas chromatography and whole genome differential expression study was carried out using expression microarray and candidate genes were validated using Real time RT-PCR.Results:Significant level of OCP residues such as β-hexachlorocyclohexane (β-HCH), Heptachlor, Heptachlor epoxide B (HTEB), dichlorodiphenyldichloroethylene (p’p’-DDE) and endosulfan-I was found between healthy and EOC patients. The transcriptome profile of several genes revealed regulation of various important cellular processes such as metabolism, inflammation, cytoskeleton dysregulation of TGF and WNT pathway in EOC cases with high OCPs.Conclusion:This study provides the first evidence showing that differentially expressed genes and dysregulation of signaling pathways might be associated with significant level of OCPs exposure in ovary tissue of epithelial ovarian cancer patients. Moreover, significant correlation of these genes with OCPs revealed that OCPs exposure played vital role in dysregulation of related pathways in the etiology of EOC

Consecutive epigenetically-active agent combinations act in ID1-RUNX3-TET2 and HOXA pathways for Flt3ITD+ve AML

Co-occurrence of Flt3ITD and TET2 mutations provoke an animal model of AML by epigenetic repression of Wnt pathway antagonists, including RUNX3, and by hyperexpression of ID1, encoding Wnt agonist. These affect HOXA over-expression and treatment resistance. A comparable epigenetic phenotype was identified among adult AML patients needing novel intervention. We chose combinations of targeted agents acting on distinct effectors, at the levels of both signal transduction and chromatin remodeling, in relapsed/refractory AML’s, including Flt3ITD+ve, described with a signature of repressed tumor suppressor genes, involving Wnt antagonist RUNX3, occurring along with ID1 and HOXA over-expressions. We tracked patient response to combination of Flt3/Raf inhibitor, Sorafenib, and Vorinostat, pan-histone deacetylase inhibitor, without or with added Bortezomib, in consecutive phase I trials. A striking association of rapid objective remissions (near-complete, complete responses) was noted to accompany induced early pharmacodynamic changes within patient blasts in situ, involving these effectors, significantly linking RUNX3/Wnt antagonist de-repression (80%) and ID1 downregulation (85%), to a response, also preceded by profound HOXA9 repression. Response occurred in context of concurrent TET2 mutation/hypomorphy and Flt3ITD+ve mutation (83% of complete responses). Addition of Bortezomib to the combination was vital to attainment of complete response in Flt3ITD+ve cases exhibiting such Wnt pathway dysregulation.