Discoidin Domain Receptor Tyrosine Kinase Research Articles

PTSD-like mice display negative cardiac characteristics post-inescapable foot shock

Post-traumatic stress disorder (PTSD) is a risk factor for cardiovascular disease, however the mechanism behind this correlation is unknown. We hypothesized that PTSD alters cardiac homeostasis by increasing macrophage numbers and initiating cardiac fibrosis. To induce experimental PTSD, male and female C57BL/6 mice (4-weeks: n=16-17/sex, males=4.7±0.4 months old; females=4.8±0.3 months old; 8-weeks: n=13-16/sex, males=6.0±0.3 months old; females=6.3±0.5 months old) were exposed to 5 separate foot-shock incidences (IFS; 1.0 mA, 1 sec duration) in 6 min. Control mice (n=8-9/sex) were placed in the same chambers but experienced no foot shocks. Behavioral tests (16 parameters based on the DSM-5 clinical standards) were performed to characterize mice that do not demonstrate PTSD-like behavioral characteristics (NR) and PTSD-like mice. Doppler echocardiography measurements were collected serially up to 8-weeks post-IFS. Histological and gene assessments were collected 4- and 8-weeks post-IFS to measure markers of adverse cardiac remodeling that resulted in later functional changes. Over time PTSD-like mice demonstrated a decline in cardiac function becoming significantly impaired by 8-weeks as shown by an increase in E/e’ ratio along with left atrial diameter compared to controls, indicative of impaired LV filling pressure and diastolic dysfunction (p<0.05 for all). Beginning at 4-weeks post-IFS, PTSD-like mice had increased picrosirius red staining (PSR) compared to control mice (p<0.05) that remained elevated at 8-weeks. PTSD-like mice had increased macrophage numbers (Mac3) at 4-weeks post-IFS compared to control mice (p<0.05) and showed an increased trend when compared to controls 8-weeks post-IFS (p=0.09). To determine potential signaling mechanisms, Ccl2, Ccl5, and discoidin domain receptor tyrosine kinase 2 (DDR2) mRNA levels were assessed. Gene expression of Ccl2 demonstrated a decreased trend in PTSD-like mice (p=0.13), while Ccl5 (p=0.08) and DDR2 (p=0.06) mRNA demonstrated an increased trend in PTSD-like mice when compared to controls. Our data indicates that in a mouse model of PTSD, animals that demonstrate PTSD-like behaviors show signs of increased cardiac inflammation stimulating cardiac remodeling and cardiac dysfunction. This work was supported by the National Institutes of Health T32GM123055; the American Heart Association Innovator Project IPA35260039, GM113278; the Biomedical Laboratory Research and Development Service of the Veterans Affairs Offce of Research and Development Award IK2BX003922, I01BX00584; and South Carolina Translational Research Center UL1TR001450. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Abstract 359: The Hippo pathway on breast tumor recurrence <and> collateral vulnerability to ferroptosis

Abstract Comparing with primary breast tumors, recurrent breast cancers are generally considered more aggressive and incurable. Therefore, novel molecular strategies are urgently needed to target these type of cancers. Here, we report that murine recurrent breast tumor cells are highly susceptible to ferroptosis, a novel form of cell death. Discoidin Domain Receptor Tyrosine Kinase 2 (DDR2), the receptor for collagen I, is upregulated in ferroptosis-sensitive recurrent tumor cells. Ferroptosis inducer, erastin treatment leads to DDR2 upregulation and phosphorylation, independent of collagen I. Furthermore, DDR2 silencing not only prevent ferroptosis but also abolished the robust cell proliferation of murine recurrent tumor cells. Both the ferroptosis protection and reduction of active cell growth may be compatible with the compromised YAP/TAZ upon DDR2 inhibition. Collectively, these findings suggest the role of DDR2 in recurrent breast tumors to drive aggressive cell growth but at the same time reveals its weakness to YAP/TAZ-mediated ferroptosis, providing potential molecular mechanism to target recurrent breast cancers. Citation Format: Chao-Chieh Lin, Jen-Tsan Chi. The Hippo pathway on breast tumor recurrence <and> collateral vulnerability to ferroptosis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 359.

Discoidin Domain Receptor Tyrosine Kinase 1 (DDR1) Is a Novel Therapeutic Target in Liposarcoma: A Tissue Microarray Study.

Liposarcoma is the most commonly diagnosed subtype of soft tissue sarcoma. As these tumors often arise near vital organs and neurovascular structures, complete resection can be challenging; consequently, recurrence rates are high. Additionally, available chemotherapeutic agents have shown limited benefit and substantial toxicities. There is, therefore, a clear and unmet need for novel therapeutics for liposarcoma. Discoidin domain receptor tyrosine kinase 1 (DDR1) is involved in adhesion, proliferation, differentiation, migration, and metastasis in several cancers. However, the expression and clinical importance of DDR1 in liposarcoma are unknown. The purposes of this study were to assess (1) the expression, (2) the association between DDR1 and survival, and (3) the functional roles of DDR1 in liposarcoma. The correlation between DDR1 expression in tumor tissues and clinicopathological features and survival was assessed via immunohistochemical staining of a liposarcoma tissue microarray. It contained 53 samples from 42 patients with liposarcoma and 11 patients with lipoma. The association between DDR1 and survival in liposarcoma was analyzed by Kaplan-Meier plots and log-rank tests. The DDR1 knockout liposarcoma cell lines were generated by CRISPR-Cas9 technology. The DDR1-specific and highly selective DDR1 inhibitor 7RH was applied to determine the impact of DDR1 expression on liposarcoma cell growth and proliferation. In addition, the effect of DDR1 inhibition on liposarcoma growth was further accessed in a three-dimensional cell culture model to mimic DDR1 effects in vivo. The results demonstrate elevated expression of DDR1 in all liposarcoma subtypes relative to benign lipomas. Specifically, high DDR1 expression was seen in 55% (23 of 42) of liposarcomas and no benign lipomas. However, DDR1 expression was not found to be associated with poor survival in patients with liposarcoma. DDR1 knockout or treatment of 7RH showed decreased liposarcoma cell growth and proliferation. DDR1 is aberrantly expressed in liposarcoma, and it contributes to several markers of oncogenesis in these tumors. This work supports DDR1 as a promising therapeutic target in liposarcoma.

Discoidin Domain Receptor-Driven Gene Signatures as Markers of Patient Response to Anti-PD-L1 Immune Checkpoint Therapy.

Anti-programmed cell death 1 (anti-PD-1) and PD ligand 1 (PD-L1) immune checkpoint therapies (ICTs) provided durable responses only in a subset of cancer patients. Thus, biomarkers are needed to predict nonresponders and offer them alternative treatments. We recently implicated discoidin domain receptor tyrosine kinase 2 (DDR2) as a contributor to anti-PD-1 resistance in animal models; therefore, we sought to investigate whether this gene family may provide ICT response prediction. We assessed mRNA expression of DDR2 and its family member DDR1. Transcriptome analysis of bladder cancer (BCa) models in which DDR1 and 2 were perturbed was used to derive DDR1- and DDR2-driven signature scores. DDR mRNA expression and gene signature scores were evaluated using BCa-The Cancer Genome Atlas (n = 259) and IMvigor210 (n = 298) datasets, and their relationship to BCa subtypes, pathway enrichment, and immune deconvolution analyses was performed. The potential of DDR-driven signatures to predict ICT response was evaluated and independently validated through a statistical framework in bladder and lung cancer cohorts. All statistical tests were 2-sided. DDR1 and DDR2 showed mutually exclusive gene expression patterns in human tumors. DDR2high BCa exhibited activation of immune pathways and a high immune score, indicative of a T-cell-inflamed phenotype, whereas DDR1high BCa exhibited a non-T-cell-inflamed phenotype. In IMvigor210 cohort, tumors with high DDR1 (hazard ratio [HR] = 1.53, 95% confidence interval [CI] = 1.16 to 2.06; P = .003) or DDR2 (HR = 1.42, 95% CI = 1.01 to 1.92; P = .04) scores had poor overall survival. Of note, DDR2high tumors from IMvigor210 and CheckMate 275 (n = 73) cohorts exhibited poorer overall survival (HR = 1.56, 95% CI = 1.20 to 2.06; P < .001) and progression-free survival (HR = 1.77 95%, CI = 1.05 to 3.00; P = .047), respectively. This result was validated in independent cancer datasets. These findings implicate DDR1 and DDR2 driven signature scores in predicting ICT response.

Hepatic kinome atlas: An in-depth identification of kinase pathways in liver fibrosis of humans and rodents.

Resolution of pathways that converge to induce deleterious effects in hepatic diseases, such as in the later stages, have potential antifibrotic effects that may improve outcomes. We aimed to explore whether humans and rodents display similar fibrotic signaling networks. We assiduously mapped kinase pathways using 340 substrate targets, upstream bioinformatic analysis of kinase pathways, and over 2000 random sampling iterations using the PamGene PamStation kinome microarray chip technology. Using this technology, we characterized a large number of kinases with altered activity in liver fibrosis of both species. Gene expression and immunostaining analyses validated many of these kinases as bona fide signaling events. Surprisingly, the insulin receptor emerged as a considerable protein tyrosine kinase that is hyperactive in fibrotic liver disease in humans and rodents. Discoidin domain receptor tyrosine kinase, activated by collagen that increases during fibrosis, was another hyperactive protein tyrosine kinase in humans and rodents with fibrosis. The serine/threonine kinases found to be the most active in fibrosis were dystrophy type 1 protein kinase and members of the protein kinase family of kinases. We compared the fibrotic events over four models: humans with cirrhosis and three murine models with differing levels of fibrosis, including two models of fatty liver disease with emerging fibrosis. The data demonstrate a high concordance between human and rodent hepatic kinome signaling that focalizes, as shown by our network analysis of detrimental pathways. Our findings establish a comprehensive kinase atlas for liver fibrosis, which identifies analogous signaling events conserved among humans and rodents.

E-Cadherin-Deficient Cells Are Sensitive to the Multikinase Inhibitor Dasatinib.

Simple SummaryInactivating mutations in the CDH1 gene, encoding the cell adhesion protein E-cadherin, cause hereditary diffuse gastric cancer syndrome (HDGC), as well as being a hallmark of sporadic diffuse gastric cancers and lobular breast cancers. We have previously identified AKT3 as a potential vulnerability in gastric cancers lacking CDH1 expression. This study aimed to test whether drugs which inhibit the AKT3-associated gene, discoidin domain receptor tyrosine kinase 2 (DDR2) specifically targeted cells deficient in E-cadherin. We demonstrated that cells and organoids lacking E-cadherin exhibited heightened sensitivity to dasatinib, a drug that targets multiple kinases including DDR2 and SRC.The CDH1 gene, encoding the cell adhesion protein E-cadherin, is one of the most frequently mutated genes in gastric cancer and inactivating germline CDH1 mutations are responsible for the cancer syndrome hereditary diffuse gastric cancer (HDGC). CDH1-deficient gastric cancers exhibit high AKT serine/threonine kinase 3 (AKT3) expression, but specific drugs against this AKT isoform are not available. We therefore used two publicly available datasets to identify AKT3-associated genes which could be used to indirectly target AKT3. Reactome analysis identified an enrichment of extracellular matrix remodelling genes in AKT3-high gastric cancers. Of the 51 genes that were significantly correlated with AKT3 (but not AKT1), discoidin domain receptor tyrosine kinase 2 (DDR2) showed the strongest positive association. Treatment of isogenic human cells and mouse gastric and mammary organoids with dasatinib, a small molecule inhibitor of multiple kinases including SRC, BCR-ABL and DDR2, preferentially slowed the growth and induced apoptosis of E-cadherin-deficient cells. Dasatinib treatment also preferentially slowed the growth of gastric and mammary organoids harbouring both Cdh1 and Tp53 mutations. In organoid models, dasatinib treatment was associated with decreased phosphorylation of total AKT, with a stronger effect seen in Cdh1-deficient organoids. Treatment with combinations of dasatinib and an inhibitor of AKT, MK2206, enhanced the effect of dasatinib in breast MCF10A cells. In conclusion, targeting the DDR2-SRC-AKT3 axis with dasatinib represents a promising approach for the chemoprevention and chemotherapy of gastric and breast cancers lacking E-cadherin.

Highlights from Recent Cancer Literature

Highlights from Recent Cancer Literature

Surgical procedures and innovative approaches for vitiligo regenerative treatment and melanocytorrhagy.

Surgical treatments for vitiligo are a safe and effective treatment modality for select patients with vitiligo. Many techniques of vitiligo surgery exist, each with unique advantages and disadvantages. We reviewed the various surgical therapies and innovative approaches for vitiligo regenerative treatment reported in the literature. Surgical therapies can be subdivided into tissue grafting methods and cellular grafting methods. Tissue grafting methods mainly include mini punch grafts, suction blister roof grafts, and hair follicle grafts. Cellular grafting methods include cultured and non-cultured treatments. The efficacy needs to be improved largely due to the poor proliferation and quality of the autologous melanocytes. Rho-associated protein kinase inhibitor enhances primary melanocyte culture proliferation from vitiligo patients to prevent apoptosis. Innovative approaches using stem cell methods could prove invaluable in developing a novel cell therapy for patients suffering from vitiligo. We succeeded in inducing melanin pigmentation in mice skin in vivo using our human induced pluripotent stem cell-derived melanocytes. In addition, we reviewed melanocytorrhagy, detachment and transepidermal loss of melanocytes, and melanocyte-related adhesion molecules. These adhesion molecules include epithelial cadherin, discoidin domain receptor tyrosine kinase 1, glycoprotein non-metastatic melanoma protein B, macrophage migration inhibiting factor, 17β-hydroxysteroid dehydrogenase 1, and E26 transformation-specific 1.

Breast tissue regeneration is driven by cell-matrix interactions coordinating multi-lineage stem cell differentiation through DDR1

Mammary morphogenesis is an orchestrated process involving differentiation, proliferation and organization of cells to form a bi-layered epithelial network of ducts and lobules embedded in stromal tissue. We have engineered a 3D biomimetic human breast that makes it possible to study how stem cell fate decisions translate to tissue-level structure and function. Using this advancement, we describe the mechanism by which breast epithelial cells build a complex three-dimensional, multi-lineage tissue by signaling through a collagen receptor. Discoidin domain receptor tyrosine kinase 1 induces stem cells to differentiate into basal cells, which in turn stimulate luminal progenitor cells via Notch signaling to differentiate and form lobules. These findings demonstrate how human breast tissue regeneration is triggered by transmission of signals from the extracellular matrix through an epithelial bilayer to coordinate structural changes that lead to formation of a complex ductal-lobular network.

Circulating Tumor Cell-Based Messenger RNA Scoring System for Prognostication of Hepatocellular Carcinoma: Translating Tissue-Based Messenger RNA Profiling Into a Noninvasive Setting.

Numerous studies in hepatocellular carcinoma (HCC) have proposed tissue-based gene signatures for individualized prognostic assessments. Here, we develop a novel circulating tumor cell (CTC)-based transcriptomic profiling assay to translate tissue-based messenger RNA (mRNA) signatures into a liquid biopsy setting for noninvasive HCC prognostication. The HCC-CTC mRNA scoring system combines the NanoVelcro CTC Assay for enriching HCC CTCs and the NanoString nCounter platform for quantifying the HCC-CTC Risk Score (RS) panel in enriched HCC CTCs. The prognostic role of the HCC-CTC RS was assessed in The Cancer Genome Atlas (TCGA) HCC cohort (n=362) and validated in an independent clinical CTC cohort (n=40). The HCC-CTC RS panel was developed through our integrated data analysis framework of 8 HCC tissue-based gene signatures and identified the top 10 prognostic genes (discoidin domain receptor tyrosine kinase 1 [DDR1], enoyl-CoA hydratase and 3-hydroxyacyl CoA dehydrogenase [EHHADH], androgen receptor [AR], lumican [LUM], hydroxysteroid 17-beta dehydrogenase 6[HSD17B6], prostate transmembrane protein, androgen induced 1 [PMEPA1], tsukushi, small leucine rich proteoglycan [TSKU], N-terminal EF-hand calcium binding protein 2 [NECAB2], ladinin 1 [LAD1], solute carrier family 27 member 5 [SLC27A5]) highly expressed in HCC with low expressions in white blood cells. The panel accurately discriminated overall survival in TCGA HCC cohort (hazard ratio [HR], 2.0; 95% confidence interval [CI], 1.4-2.9). The combined use of the scoring system and HCC-CTC RS panel successfully distinguished artificial blood samples spiked with an aggressive HCC cell type, SNU-387, from those spiked with PLC/PRF/5 cells (P=0.02). In the CTC validation cohort (n=40), HCC-CTC RS remained an independent predictor of survival (HR, 5.7; 95% CI, 1.5-21.3; P=0.009) after controlling for Model for End-Stage Liver Disease score, Barcelona Clinic Liver Cancer stage, and CTC enumeration count. Our study demonstrates a novel interdisciplinary approach to translate tissue-based gene signatures into a liquid biopsy setting. This noninvasive approach will allow real-time disease profiling and dynamic prognostication of HCC.

Spondylometaepiphyseal Dysplasia Short Limb-Abnormal Calcification Type in Turkish Patients Reveals a Novel Mutation and New Features

Spondylometaepiphyseal dysplasia short limb-abnormal calcification type (SMED-SL/AC) is a rare autosomal recessive disorder. It is a severe dwarfism syndrome with a characteristic feature of progressive calcification of epiphyseal and other cartilaginous tissues. It is caused by pathogenic variants in the DDR2 gene encoding the discoidin domain receptor tyrosine kinase 2. Thus far, 37 cases and 8 pathogenic variants have been reported. Most of the reported cases are of Middle Eastern and Puerto Rican origins. Only one Turkish case has been reported previously with a novel truncating variant p.(R489*). Here, we report 2 new cases, 1 with a novel variant p.(S311G) and 1 with a splice site variant c.2283+1G>A. In addition, we reviewed a previously reported case, and sequencing of stored DNA revealed the recently reported nonsense variant p.(R489*) as the underlying cause. Therefore, our data increase the number of SMED-SL/AC Turkish patients with molecular results to 4. Furthermore, we compared the features of Turkish patients with other reported cases and expanded the characteristics of the disorder with new features such as triventricular hydrocephalus, intracranial hemorrhage, hypopigmentation of hair, dry and scaly skin, arthralgia, and hypocalcemia. We also compared the pathogenic variants of Turkish patients with other variants, aiming to explain the mechanism leading to a more severe and early fatal course in Turkish patients.

Discoidin Domain Receptor Tyrosine Kinase 1 (DDR1): A Novel Predictor for Recurrence of Hepatocellular Carcinoma After Curative Resection

BackgroundPrevious studies showed that the discoidin domain receptor tyrosine kinase 1 (DDR1) is significantly elevated in a variety of cancers, and it is closely related to the occurrence and development of tumors. However, its clinical significance in hepatocellular carcinoma (HCC) is not fully elucidated. So, in this study, we aimed to systemically evaluate the prognostic value of DDR1 in HCC.Material/MethodsA total of 200 individuals were enrolled in this study (including 120 HCC patients, 40 chronic hepatitis patients, and 40 health individuals). The contents of DDR1 in serum was measured by enzyme-linked immunosorbent assay (ELISA), while the expression level of DDR1 in para-tumor and tumor tissue was detected by immunohistochemistry staining. Kaplan-Meier, Cox regression analyses, and log-rank test were used to assess the prognostic value.ResultsThe contents of DDR1 in serum of HCC patients was significantly higher compared with chronic hepatitis patients (P<0.01) and health individuals (P<0.001). The expression level of DDR1 in tumors was higher than that in normal liver tissue, and it had relatively strong correlation with DDR1 in serum. We next demonstrated that high DDR1 has utility as a prognostic risk factor for tumor recurrence and metastasis, and it still retains its discrimination ability in low-risk groups (BCLC 0+A). Moreover, DDR1 is as an independent predictor of prognosis in HCC patients with microvascular invasion (MVI), and is strongly associated with epithelial-mesenchymal transition (EMT)-related protein.ConclusionsDDR1 is a novel predictor for HCC recurrence. Integration of serum and tumor DDR1 detection into clinical management would provide convenience and enhanced accuracy in clinical practice.

Coexpression of the discoidin domain receptor 1 gene with oligodendrocyte-related and schizophrenia risk genes in the developing and adult human brain.

BackgroundDiscoidin domain receptor tyrosine kinase 1 (DDR1) is present in multiple types of epithelial cells and is highly expressed in the nervous system. Previous studies have revealed that DDR1 is involved in schizophrenia (SCZ). Although the expression of DDR1 in oligodendrocytes has been described, its role in brain myelination is not well understood. In this study, we aimed to explore the coexpression network of DDR1 in the human brain and to compare the list of DDR1 coexpressing genes with the list of genes containing single nucleotide polymorphisms (SNPs) that are associated with SCZ.Materials and MethodsWe used a weighted gene coexpression network analysis (WGCNA) of a dataset from four brain areas (the dorsolateral prefrontal cortex, primary motor cortex, hippocampus, and striatum) and from four different intervals (I) of life (I‐1 = 10–38 weeks postconception, I‐2 ≥0 to < 6 years, I‐3 ≥ 6 to < 40 years, and I‐4 ≥ 40 years of age). We compared the list of genes that are associated with SCZ in the GWAS Catalog with the list of genes coexpressing with DDR1 in each interval.ResultsOur study revealed that DDR1 was coexpressed with oligodendrocyte‐related genes mainly in I‐2 (adjP = 5.66e‐24) and I‐3 (adjP = 2.8e‐114), which coincided with the coexpression of DDR1 with myelination‐related genes (adjP = 9.04e‐03 and 2.51e‐08, respectively). DDR1 was also coexpressed with astrocyte‐related genes in I‐1 (adjP = 1.11e‐71), I‐2 (adjP = 2.12e‐20) and I‐4 (adjP = 9.93e‐52) and with type 2 microglia‐related genes in I‐1 (adjP = 2.84e‐08), I‐2 (adjP = 5.68e‐16) and I‐4 (adjP = 3.66e‐10). Moreover, we observed significant enrichment of SCZ susceptibility genes within the coexpression modules containing DDR1 in I‐1 and I‐4 (P = 1e‐04 and 0.0037, respectively), during which the DDR1 module showed the highest association with the astrocytes.ConclusionsOur study confirmed that DDR1 is coexpressed with oligodendrocyte‐ and myelin‐related genes in the human brain but suggests that DDR1 may contribute mainly to SCZ risk through its role in other glial cell types, such as astrocytes.

DDR2 upregulation confers ferroptosis susceptibility of recurrent breast tumors through the Hippo pathway.

Recurrent breast cancer presents significant challenges with aggressive phenotypes and treatment resistance. Therefore, novel therapeutics are urgently needed. Here, we report that murine recurrent breast tumor cells, when compared with primary tumor cells, are highly sensitive to ferroptosis. Discoidin Domain Receptor Tyrosine Kinase 2 (DDR2), the receptor for collagen I, is highly expressed in ferroptosis-sensitive recurrent tumor cells and human mesenchymal breast cancer cells. EMT regulators, TWIST and SNAIL, significantly induce DDR2 expression and sensitize ferroptosis in a DDR2-dependent manner. Erastin treatment induces DDR2 upregulation and phosphorylation, independent of collagen I. Furthermore, DDR2 knockdown in recurrent tumor cells reduces clonogenic proliferation. Importantly, both the ferroptosis protection and reduced clonogenic growth may be compatible with the compromised YAP/TAZ upon DDR2 inhibition. Collectively, these findings identify the important role of EMT-driven DDR2 upregulation in recurrent tumors in maintaining growth advantage but activating YAP/TAZ-mediated ferroptosis susceptibility, providing potential strategies to eradicate recurrent breast cancer cells with mesenchymal features.

Identification of a novel homozygous mutation in the DDR2 gene from a patient with spondylo-meta-epiphyseal dysplasia by whole exome sequencing.

Objective(s):The spondylo-meta-epiphyseal dysplasia (SMED) short limbs-hand type is a rare autosomal recessive disease, which is characterized by premature calcification leading to severe disproportionate short stature and various skeletal changes. Defective function of a conserved region encoding discoidin domain receptor tyrosine kinase 2 (DDR2 protein) by the discoidin domain-containing receptor 2 (DDR2 gene) is cause of this disease. The purpose of present study was to investigate disease-causing mutations on DDR2 gene in an Iranian family with SMED, and predict the DDR2 protein molecular mechanism in development of SMED.Materials and Methods: In the present study, we evaluated a 2-year-old male with SMED. Detection of genetic changes in the studied patient was performed using Whole-Exome Sequencing (WES). PCR direct sequencing was performed for analysis of co-segregation of variants with the disease in family. Finally, in silico study was performed for further identification of molecular function of the identified genetic variant.Results:We detected a novel splice-site mutation (NM_001014796: exon9: c.855+1G>A; NM_006182: exon8: c.855+1G>A) in DDR2 gene of the studied patient using WES. This mutation was exclusively detected in patients with homozygous SMED, not in healthy people. The effects of detected mutation on functions of DDR2 protein was predicted using in silico study.Conclusion:The causative mutation in studied patient with SMED was identified using Next-generation sequencing (NGS), successfully. The identified novel mutation in DDR2 gene can be useful in prenatal diagnosis (PND) of SMED, preimplantation genetic diagnosis (PGD), and genetic counseling.

Mitochondria-related core genes and TF-miRNA-hub mrDEGs network in breast cancer.

Background: Mitochondria-nuclear cross-talk and mitochondrial retrograde regulation are involved in the genesis and development of breast cancer (BC). Therefore, mitochondria can be regarded as a promising target for BC therapeutic strategies. The present study aimed to construct regulatory network and seek the potential biomarkers of BC diagnosis and prognosis as well as the molecular therapeutic targets from the perspective of mitochondrial dysfunction. Methods: The microarray data of mitochondria-related encoding genes in BC cell lines were downloaded from GEO including GSE128610 and GSE72319. GSE128610 was treated as test set and validation sets consisted of GSE72319 and TCGA tissue samples, intending to identify mitochondria-related differentially expressed genes (mrDEGs). We performed enrichment analysis, PPI network, hub mrDEGs and overall survival analysis and constructed transcription factor (TF)-miRNA-hub mrDEGs network. Results: A total of 23 up-regulated and 71 down-regulated mrDEGs were identified and validated in BC cell lines and tissues. Enrichment analyses indicated that mrDEGs were associated with several cancer-related biological processes. Moreover, 9 hub mrDEGs were identified and validated in BC cell lines and tissues. Finally, 5 hub coregulated mrDEGs, 21 miRNAs and 117 TFs were used to construct TF-miRNA-hub mrDEGs network. MYC associated zinc finger protein (MAZ), heparin binding growth factor (HDGF) and Sp2 transcription factor (SP2) regulated 3 hub mrDEGs. Hsa-mir-21-5p, hsa-mir-1-3p, hsa-mir-218-5p, hsa-mir-26a-5p and hsa-mir-335-5p regulated 2 hub mrDEGs. Overall survival analysis suggested that the up-regulation of fibronectin 1 (FN1), as well as the down-regulation of discoidin domain receptor tyrosine kinase 2 (DDR2) correlated with unfavorable prognosis in BC. Conclusion: TF-miRNA-hub mrDEGs had instruction significance for the exploration of BC etiology. The hub mrDEGs such as FN1 and DDR2 were likely to regulate mitochondrial function and be novel biomarkers for BC diagnosis and prognosis as well as the therapeutic targets.

ASSOCIATION BETWEEN GENETIC VARIANTS OF SINGLE NUCLEOTIDE POLYMORPHISMS OF THE DISCOIDIN DOMAIN RECEPTOR TYROSINE KINASE 1 (DDR1) A/C (RS 2267641) AND GRANZYME B (GZMB) C/T (RS8192917) GENES IN VITILIGO

Vitiligo manifests as advanced loss of melanocytes with reduced cellular adhesion. Discoidin Domain Receptor Tyrosine kinase1 (DDR1) is a main element affecting cellular adhesiveness associated with vitiligo. Granzyme B (GZMB) has significant role in cytotoxic T-cell induced apoptosis. This study aimed to evaluate the association between genetic variants of single nucleotide polymorphisms of DDR1 A/C (rs 2267641) and GZMB C/T (rs8192917) and the risk of developing vitiligo. The genotypes were investigated using allele discrimination assay comparing 120 patients having non-segmental vitiligo and 100 age and gender matched healthy individuals. We detected a significant prevalence of the CC genotype and C allele of both DDR1 and GZMB polymorphisms in vitiligo patients with early onset and progressive course compared to controls. Our results concluded that DDR1 A/C (rs 2267641) and GZMB C/T (rs8192917) polymorphisms may be risk factors for vitiligo.

MiR-199b-5p-DDR1-ERK signalling axis suppresses prostate cancer metastasis via inhibiting epithelial-mesenchymal transition.

BackgroundThe investigation of underlying mechanism and the exploitation of novel therapies for metastatic prostate cancer (PCa) are still urgently needed. miR-199b-5p has been suggested to function as tumour suppressor in various human cancers. However, the clinical significance and role of miR-199b-5p in PCa remain unclear.MethodsThe current study sought to investigate the expression status of miR-199b-5p in PCa and the involved molecular mechanisms in PCa metastasis by using bioinformatics analyses, loss-and gain-of-functions and rescue experiments in vitro and in vivo.ResultsWe demonstrated that miR-199b-5p was significantly downregulated in metastatic PCa tissues and cells when compared with the normal prostate tissue, the localised disease, the weakly metastatic and androgen-dependent PCa cell and the normal prostate epithelial cell. We also found that miR-199b-5p drastically suppressed PCa cell proliferation, migration and invasion in vitro and inhibited xenografts tumour growth and metastasis in vivo. Mechanistically, our results showed that miR-199b-5p could inhibit discoidin domain receptor tyrosine kinase 1 (DDR1) expression by directly targeting its 3’-UTR, thereby hindering epithelial-mesenchymal transition (EMT)-associated traits, which were induced by DDR1 activating ERK signalling pathway. Moreover, PCa patients with low miR-199b-5p expression level had a remarkably shorter overall survival than those with high miR-199b-5p level, indicating an association of miR-199b-5p loss with poor prognosis in patients with PCa. Furthermore, DDR1 was upregulated in PCa, and significantly correlated with high Gleason score, advanced pathological stage, tumour metastasis and shorter overall survival.ConclusionsOur study, for the first time, provide evidence of a tumour-suppressive function of miR-199b-5p in the invasion and metastasis of PCa, supporting the translational exploitation of miR-199b-5p-based therapeutic approaches for PCa metastases. Also, the miR-199b-5p-DDR1-ERK signalling axis identified in this study represents a novel mechanism of regulating EMT in PCa metastases.

Early-onset colorectal cancer: A distinct entity with unique genetic features.

The aim of the present study was to elucidate the genetic features of early-onset colorectal cancer (CRC), particularly the genetic mutations that may be regarded as prognostic and/or predictive markers in CRC and other malignancies. In total, 40 patients with non-polyposis CRC aged 35 or younger were selected. The formalin-fixed, paraffin-embedded tumors acquired were subjected to mismatch repair (MMR) protein immunochemical staining and gene analysis with next-generation sequencing (44 exons, 17 genes; Ion Torrent Sequencing Platform). A total of 11 (27.5%) tumors presented with MMR protein deficiency (dMMR) and 26 (65%) tumors harbored one or more genetic mutations, including K-RAS proto-oncogene (35%), phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha (PIK3CA; 20%), B-Raf proto-oncogene (5%), erb-b2 receptor tyrosine kinase 2 (5%), discoidin domain receptor tyrosine kinase 2 (5%), N-RAS proto-oncogene (2.5%), KIT proto-oncogene (2.5%), TSC complex subunit 1 (2.5%), DNA methyltransferase 3 alpha (2.5%) and ABL proto-oncogene 1 (2.5%). Of the dMMR tumors, 81.8% (9/11) of cases presented with mutations in the tested genes, while only 58.6% (17/29) of the MMR-proficient (pMMR) tumors presented with these (P=0.158). PI3KCA was frequently mutated in dMMR tumors compared to pMMR tumors (P=0.025). In a subgroup with a family history of CRC, the dMMR status (P<0.001) and PIK3CA genetic mutation status (P=0.01) were more frequently observed compared to the other two groups (with a family history of other cancer types or no malignancy). Almost all patients who had relatives with CRC presented with both dMMR and other genetic mutations, while this was not observed in the patients who had relatives with other types of carcinoma. Certain genetic mutations that are rarely reported in CRC were only identified in those patients with a family history of carcinoma. In conclusion, non-polyposis CRC in young adults presents as a distinct entity with a unique set of genetic features. However, investigation of more cases in further studies is required to verify the present results.

Over expression of CDK4 and MDM2 in a patient with recurrent ALK-negative mediastinal inflammatory myofibroblastic tumor

Rationale:The diagnosis of anaplastic lymphoma kinase (ALK)-negative inflammatory myofibroblastic tumors (IMT) remains challenging because of their morphological resemblance with spindle cell sarcoma with myofibroblastic characteristics.Patient concerns:A 69-year-old female patient presented with loco-regional recurrent IMT several times within 8 years after primary treatment and neck lymph node metastasis 3.5 years after last recurrence.Diagnosis:The primary, recurrence, and lymph node metastasis lesions were diagnosed as ALK-negative IMTs based on the histopathological features.Interventions:Biopsy samples were obtained during repeated surgeries and evaluated for genomic alterations during first and recurrent presentations. The evaluation was done using pathway-driven massive parallel sequencing, and genomic alterations between primary and recurrent tumors were compared.Outcomes:Copy number gains and overexpression of mouse double minute 2 homolog (MDM2) and cyclin dependent kinase 4 (CDK4) were observed in the primary lesion, and additional gene amplification of Discoidin Domain Receptor Tyrosine Kinase 2 (DDR2), Succinate Dehydrogenase Complex II subunit C (SDHC), and thyroid stimulating hormone receptor (TSHR) Q720H were found in the recurrent tumors. Metastases to the neck lymph node were observed 3.5 years after recurrence.Lessons:Our results indicated genetic evolution in a microscopically benign condition and highlighted the importance of molecular characterization of fibro-inflammatory lesions of uncertain malignant potential.