Gene Summary

Gene:DDR2; discoidin domain receptor tyrosine kinase 2
Aliases: TKT, MIG20a, NTRKR3, TYRO10
Summary:Receptor tyrosine kinases (RTKs) play a key role in the communication of cells with their microenvironment. These molecules are involved in the regulation of cell growth, differentiation, and metabolism. In several cases the biochemical mechanism by which RTKs transduce signals across the membrane has been shown to be ligand induced receptor oligomerization and subsequent intracellular phosphorylation. This autophosphorylation leads to phosphorylation of cytosolic targets as well as association with other molecules, which are involved in pleiotropic effects of signal transduction. RTKs have a tripartite structure with extracellular, transmembrane, and cytoplasmic regions. This gene encodes a member of a novel subclass of RTKs and contains a distinct extracellular region encompassing a factor VIII-like domain. Alternative splicing in the 5' UTR results in multiple transcript variants encoding the same protein. [provided by RefSeq, Jul 2008]
Databases:OMIM, VEGA, HGNC, Ensembl, GeneCard, Gene
Protein:discoidin domain-containing receptor 2
Source:NCBIAccessed: 25 June, 2015


What does this gene/protein do?
Show (24)

Cancer Overview

Research Indicators

Publications Per Year (1990-2015)
Graph generated 25 June 2015 using data from PubMed using criteria.

Literature Analysis

Mouse over the terms for more detail; many indicate links which you can click for dedicated pages about the topic.

  • BRAF
  • Receptor, erbB-2
  • Lung Cancer
  • Oncogenes
  • Cell Movement
  • DNA Mutational Analysis
  • Mutation
  • Gene Expression Profiling
  • Cell Proliferation
  • Neoplastic Cell Transformation
  • Pyrimidines
  • Adenocarcinoma
  • Young Adult
  • Immunohistochemistry
  • Molecular Targeted Therapy
  • Thiazoles
  • Epidermal Growth Factor Receptor
  • Neoplasm Invasiveness
  • Proto-Oncogene Proteins
  • Squamous Cell Carcinoma
  • Transfection
  • Neoplasm Proteins
  • ras Proteins
  • Non-Small Cell Lung Cancer
  • Immunoenzyme Techniques
  • Receptor Protein-Tyrosine Kinases
  • Receptors, Mitogen
  • Hodgkin Lymphoma
  • Gene Rearrangement
  • Phosphorylation
  • FGFR1
  • Signal Transduction
  • Cervical Cancer
  • Chromosome 1
  • Protein Kinase Inhibitors
  • Transcription Factors
  • siRNA
  • Cancer Gene Expression Regulation
  • Messenger RNA
Tag cloud generated 25 June, 2015 using data from PubMed, MeSH and CancerIndex

Specific Cancers (4)

Data table showing topics related to specific cancers and associated disorders. Scope includes mutations and abnormal protein expression.

Note: list is not exhaustive. Number of papers are based on searches of PubMed (click on topic title for arbitrary criteria used).

Latest Publications: DDR2 (cancer-related)

Kenmotsu H, Serizawa M, Koh Y, et al.
Prospective genetic profiling of squamous cell lung cancer and adenosquamous carcinoma in Japanese patients by multitarget assays.
BMC Cancer. 2014; 14:786 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Despite considerable recent progress in the treatment of lung adenocarcinoma, there has been little progress in the development of efficacious molecular targeted therapies for squamous cell lung cancer. In addition to the recent comprehensive genome-wide characterization of squamous cell lung cancer, it is also important to genotype this form of cancer. We therefore conducted the Shizuoka Lung Cancer Mutation Study to analyze driver mutations in patients with thoracic malignancies. Here we report the results of genotyping in patients with squamous cell lung cancer.
METHODS: Based on the biobanking system, in conjunction with the clinic and pathology lab, we developed a genotyping panel designed to assess 24 mutations in 10 genes (EGFR, KRAS, BRAF, PIK3CA, NRAS, MEK1, AKT1, PTEN, HER2 and DDR2), EGFR, MET, PIK3CA, FGFR1 and FGFR2 copy numbers, and EML4-ALK and ROS1 translocations, using pyrosequencing plus capillary electrophoresis, quantitative polymerase chain reaction (PCR) and reverse-transcription PCR, respectively.
RESULTS: A total of 129 patients with squamous cell lung cancer and adenosquamous carcinoma were enrolled in this study between July 2011 and November 2012. We detected genetic alterations in 40% of all cases. Gene alterations included: EGFR mutations, 6%; KRAS mutations, 4%; PIK3CA mutations, 13%; NRAS mutations, 1%; KIF5b-RET fusion gene, 1%; EGFR copy number gain, 5%; PIK3CA copy number gain, 15%; and FGFR1 copy number gain, 5%. Twelve patients (9%) harbored simultaneous genetic alterations. Genetic alterations were detected more frequently in surgically-resected, snap-frozen samples than in formalin-fixed, paraffin-embedded samples (50% vs. 29%). In addition, patients aged ≤70 years old and never-smokers showed high frequencies of genetic alterations.
CONCLUSIONS: This study represents one of the largest prospective tumor-genotyping studies to be performed in Asian patients with squamous cell lung cancer. These results suggest that incorporation of genetic profiling into lung cancer clinical practice may facilitate the administration of personalized cancer treatments in patients with squamous cell lung cancer.

Ren T, Zhang W, Liu X, et al.
Discoidin domain receptor 2 (DDR2) promotes breast cancer cell metastasis and the mechanism implicates epithelial-mesenchymal transition programme under hypoxia.
J Pathol. 2014; 234(4):526-37 [PubMed] Related Publications
A wide range of genes involved in breast cancer metastasis have been reported to be related to the microenvironment. We studied the role of discoidin domain receptor 2 (DDR2), a collagen-binding receptor, in breast cancer progression under hypoxic conditions. We showed that DDR2 protein expression closely correlated with the expression of hypoxic marker HIF-1α in clinical breast cancer specimens. The in vitro data demonstrated that hypoxia treatment increased the levels of both expression and phosphorylation of DDR2 in human breast cancer cell lines. In vivo, orthotopic breast tumour xenografts with DDR2 knockdown displayed reduced dissemination and significant prevention in pulmonary and lymphatic metastasis; conversely, these processes were significantly facilitated by the enforced expression of the activated form of DDR2. Further mechanism studies indicated that DDR2 plays an indispensable role in a series of hypoxia-induced behaviours of breast cancer cells, including migration, invasion, and epithelial-mesenchymal transition (EMT). The transcription factor Snail was found to mediate DDR2-induced down-regulation of the cell-cell adhesion molecule E-cadherin. It was also documented that there is a correlation between DDR2 and E-cadherin expression with the presence of lymph node metastases in 160 cases of invasive human breast carcinoma. In addition, we provided evidence that DDR2 silencing in breast cancer cells prevents the hypoxia-induced activation of ERK MAPK, suggesting its potential involvement in mediating the effect of DDR2 on hypoxia-induced signalling. Based on the results of this study, we conclude that DDR2 participates in hypoxia-induced breast cancer metastasis through the regulation of cell migration, invasion, and EMT, and thus may serve as an accessible therapeutic target for the treatment of breast cancer.

Miao L, Wang Y, Zhu S, et al.
Identification of novel driver mutations of the discoidin domain receptor 2 (DDR2) gene in squamous cell lung cancer of Chinese patients.
BMC Cancer. 2014; 14:369 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Although many of the recently approved genomically targeted therapies have improved outcomes for patients in non-small-cell lung cancer (NSCLC) with lung adenocarcinoma, little is known about the genomic alterations that drive lung squamous cell cancer (SCC) and development of effective targeted therapies in lung SCC is a promising area to be further investigated. Discoidin domain receptor 2 (DDR2), is a novel receptor tyrosine kinases that respond to several collagens and involved in tissue repair, primary and metastatic cancer progression.
METHODS: Expression of DDR2 mRNA was analyzed in 54 lung SCC tissues by qRT-PCR. Over-expression approaches were used to investigate the biological functions of DDR2 and its' mutations in lung SCC cells. Conventional Sanger sequencing was used to investigate the mutations of DDR2 gene in 86 samples. The effect of DDR2 and its' mutations on proliferation was evaluated by MTT and colony formation assays; cell migration and invasion was evaluated by trasnwell assays. Lung SCC cells stably transfected with pEGFP-DDR2 WT, pEGFP-DDR2-S131C or empty vector were injection into nude mice to study the effect of DDR2 and its' mutation on tumorigenesis in vivo. Protein and mRNA expression levels of E-cadherin and MMP2 were determined by qRT-PCR and western blot analysis. Differences between groups were tested for significance using Student's t-test (two-tailed).
RESULTS: In this study, we found that DDR2 mRNA levels were significantly decreased in 54 lung SCC tissues compared with normal lung tissues. Moreover, there were 3 novel DDR2 mutations (G531V, S131C, T681I) in 4 patients and provide the mutation rate of 4.6% in the 86 patients with lung SCC. The mutation of S131C in DDR2 could promote lung SCC cells proliferation, migration and invasion via inducing MMP-2, but reducing E-cadherin expression.
CONCLUSIONS: These data indicated that the novel DDR2 mutation may contribute to the development and progression of lung SCC and this effect may be associated with increased proliferation and invasiveness, at least in part, via regulating E-cadherin expression.

Yan Z, Jin S, Wei Z, et al.
Discoidin domain receptor 2 facilitates prostate cancer bone metastasis via regulating parathyroid hormone-related protein.
Biochim Biophys Acta. 2014; 1842(9):1350-63 [PubMed] Related Publications
Prostate cancer frequently metastasizes to the skeleton but the underlying mechanism remains largely undefined. Discoidin domain receptor 2 (DDR2) is a member of receptor tyrosine kinase (RTK) family and is activated by collagen binding. This study aimed to investigate the function and detailed mechanism of DDR2 in prostate cancer bone dissemination. Herein we found that DDR2 was strongly expressed in bone-metastatic prostate cancer cells and tissues compared to that in normal controls. Enhanced expression of constitutively activated DDR2 led to elevation in motility and invasiveness of prostate cancer cells, whereas knockdown of DDR2 through specific shRNA caused a dramatic repression. Knockdown of DDR2 in prostate cancer cells resulted in significant decrease in the proliferation, differentiation and function of osteoblast. Over-expression of DDR2 in prostate cancer cells resulted in notable acceleration of osteoclast differentiation and bone resorption, whereas knockdown of DDR2 exhibited the opposite effects. An intrabone injection bone metastasis animal model demonstrated that DDR2 promoted osteolytic metastasis in vivo. Molecular evidence demonstrated that DDR2 regulated the expression, secretion, and promoter activity of parathyroid hormone-related protein (PTHrP), via modulating Runx2 phosphorylation and transactivity. DDR2 was responsive to TGF-β and involved in TGF-β-mediated osteoclast activation and bone resorption. In addition, DDR2 facilitated prostate cancer cells adhere to type I collagen. This study reveals for the first time that DDR2 plays an essential role in prostate cancer bone metastasis. The mechanism disclosure may provide therapeutic targets for the treatment of prostate cancer.

Leitinger B
Discoidin domain receptor functions in physiological and pathological conditions.
Int Rev Cell Mol Biol. 2014; 310:39-87 [PubMed] Free Access to Full Article Related Publications
The discoidin domain receptors, DDR1 and DDR2, are nonintegrin collagen receptors that are members of the receptor tyrosine kinase family. Both DDRs bind a number of different collagen types and play important roles in embryo development. Dysregulated DDR function is associated with progression of various human diseases, including fibrosis, arthritis, and cancer. By interacting with key components of the extracellular matrix and displaying distinct activation kinetics, the DDRs form a unique subfamily of receptor tyrosine kinases. DDR-facilitated cellular functions include cell migration, cell survival, proliferation, and differentiation, as well as remodeling of extracellular matrices. This review summarizes the current knowledge of DDR-ligand interactions, DDR-initiated signal pathways and the molecular mechanisms that regulate receptor function. Also discussed are the roles of DDRs in development and disease progression.

Zhang M, Chai YD, Brumbaugh J, et al.
Oral cancer cells may rewire alternative metabolic pathways to survive from siRNA silencing of metabolic enzymes.
BMC Cancer. 2014; 14:223 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Cancer cells may undergo metabolic adaptations that support their growth as well as drug resistance properties. The purpose of this study is to test if oral cancer cells can overcome the metabolic defects introduced by using small interfering RNA (siRNA) to knock down their expression of important metabolic enzymes.
METHODS: UM1 and UM2 oral cancer cells were transfected with siRNA to transketolase (TKT) or siRNA to adenylate kinase (AK2), and Western blotting was used to confirm the knockdown. Cellular uptake of glucose and glutamine and production of lactate were compared between the cancer cells with either TKT or AK2 knockdown and those transfected with control siRNA. Statistical analysis was performed with student T-test.
RESULTS: Despite the defect in the pentose phosphate pathway caused by siRNA knockdown of TKT, the survived UM1 or UM2 cells utilized more glucose and glutamine and secreted a significantly higher amount of lactate than the cells transferred with control siRNA. We also demonstrated that siRNA knockdown of AK2 constrained the proliferation of UM1 and UM2 cells but similarly led to an increased uptake of glucose/glutamine and production of lactate by the UM1 or UM2 cells survived from siRNA silencing of AK2.
CONCLUSIONS: Our results indicate that the metabolic defects introduced by siRNA silencing of metabolic enzymes TKT or AK2 may be compensated by alternative feedback metabolic mechanisms, suggesting that cancer cells may overcome single defective pathways through secondary metabolic network adaptations. The highly robust nature of oral cancer cell metabolism implies that a systematic medical approach targeting multiple metabolic pathways may be needed to accomplish the continued improvement of cancer treatment.

Egan JB, Barrett MT, Champion MD, et al.
Whole genome analyses of a well-differentiated liposarcoma reveals novel SYT1 and DDR2 rearrangements.
PLoS One. 2014; 9(2):e87113 [PubMed] Free Access to Full Article Related Publications
Liposarcoma is the most common soft tissue sarcoma, but little is known about the genomic basis of this disease. Given the low cell content of this tumor type, we utilized flow cytometry to isolate the diploid normal and aneuploid tumor populations from a well-differentiated liposarcoma prior to array comparative genomic hybridization and whole genome sequencing. This work revealed massive highly focal amplifications throughout the aneuploid tumor genome including MDM2, a gene that has previously been found to be amplified in well-differentiated liposarcoma. Structural analysis revealed massive rearrangement of chromosome 12 and 11 gene fusions, some of which may be part of double minute chromosomes commonly present in well-differentiated liposarcoma. We identified a hotspot of genomic instability localized to a region of chromosome 12 that includes a highly conserved, putative L1 retrotransposon element, LOC100507498 which resides within a gene cluster (NAV3, SYT1, PAWR) where 6 of the 11 fusion events occurred. Interestingly, a potential gene fusion was also identified in amplified DDR2, which is a potential therapeutic target of kinase inhibitors such as dastinib, that are not routinely used in the treatment of patients with liposarcoma. Furthermore, 7 somatic, damaging single nucleotide variants have also been identified, including D125N in the PTPRQ protein. In conclusion, this work is the first to report the entire genome of a well-differentiated liposarcoma with novel chromosomal rearrangements associated with amplification of therapeutically targetable genes such as MDM2 and DDR2.

Thunnissen E, van der Oord K, den Bakker M
Prognostic and predictive biomarkers in lung cancer. A review.
Virchows Arch. 2014; 464(3):347-58 [PubMed] Related Publications
In lung cancer, clinically relevant prognostic information is provided by staging. Staging forms the basis for the treatment options and this is briefly summarized in the introduction. Epidermal growth factor receptor (EGFR) and anaplastic lymphoma kinase are biomarkers used for prediction of chemotherapy and prediction of targeted treatment. Other driver biomarkers in lung cancer (point mutations and rearrangements in specific genes including Her2, BRAF, NUT, MET, ROS1, DDR2, FGFR1, KRAS, and PTEN) might potentially provide additional information for clinical decision making. Owing to the low prevalence of mutations in predictive markers, patient numbers in studies are usually small, with the exception of EGFR. These mutations increase our understanding of the biology of lung cancer. Mutation analysis as a basis for treatment choice can have an impressive clinical impact with dramatic responses. However, as yet the impact of these approaches to overall survival is less striking.

Zhang S, Bu X, Zhao H, et al.
A host deficiency of discoidin domain receptor 2 (DDR2) inhibits both tumour angiogenesis and metastasis.
J Pathol. 2014; 232(4):436-48 [PubMed] Related Publications
Discoidin domain receptor 2 (DDR2) is a unique receptor tyrosine kinase (RTK) that signals in response to collagen binding and is implicated in tumour malignant phenotypes such as invasion and metastasis. Although it has been reported that DDR2 expression is up-regulated in activated endothelial cells (ECs), functional studies are lacking. Herein, we found that enforced expression of DDR2 promoted proliferation, migration and tube formation of primary human umbilical vein endothelial cells (HUVECs). The results of immunohistochemical analysis showed a strikingly high level of DDR2 in human tumour ECs. Most significantly, we discovered that a host deficiency of DDR2 inhibits subcutaneous angiogenesis induced by either VEGF or tumour cells. In addition, the remaining tumour vessels in DDR2-deficient mice exhibit some normalized properties. These vascular phenotypes are accompanied by the up-regulation of anti-angiogenic genes and down-regulation of pro-angiogenic genes, as well as by alleviated tumour hypoxia. By use of a tail vein metastasis model of melanoma, we uncovered that loss of stromal DDR2 also suppresses tumour metastasis to the lung. Hence, our current data disclose a new mechanism by which DDR2 affects tumour progression, and may strengthen the feasibility of targeting DDR2 as an anticancer strategy.

Shimizu T, Inoue K, Hachiya H, et al.
Frequent alteration of the protein synthesis of enzymes for glucose metabolism in hepatocellular carcinomas.
J Gastroenterol. 2014; 49(9):1324-32 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Cancer cells show enhanced glycolysis and inhibition of oxidative phosphorylation, even in the presence of sufficient oxygen (aerobic glycolysis). Glycolysis is much less efficient for energy production than oxidative phosphorylation, and the reason why cancer cells selectively use glycolysis remains unclear.
METHODS: Biospecimens were collected from 45 hepatocellular carcinoma patients. Protein samples were prepared through subcellular localization or whole-cell lysis. Protein synthesis was measured by SDS-PAGE and immunoblotting. mRNA transcription was measured using quantitative RT-PCR. Statistical correlation among immunoblotting data and clinicolaboratory factors were analyzed using SPSS.
RESULTS: Enzymes for oxidative phosphorylation (SDHA and SDHB) were frequently decreased (56 and 48 % of patients, respectively) in hepatocellular carcinomas. The lowered amount of the SDH protein complex was rarely accompanied by stabilization of HIF1α and subsequent activation of the hypoxia response. On the other hand, protein synthesis of G6PD and TKT, enzymes critical for pentose phosphate pathway (PPP), was increased (in 45 and 55 % of patients, respectively), while that of ALDOA, an enzyme for mainstream glycolysis, was eliminated (in 55 % of patients). Alteration of protein synthesis was correlated with gene expression for G6PD and TKT, but not for TKTL1, ALDOA, SDHA or SDHB. Augmented transcription and synthesis of PPP enzymes were accompanied by nuclear accumulation of NRF2.
CONCLUSION: Hepatocellular carcinomas divert glucose metabolism to the anabolic shunt by activating transcription factor NRF2.

Pan Y, Wang R, Ye T, et al.
Comprehensive analysis of oncogenic mutations in lung squamous cell carcinoma with minor glandular component.
Chest. 2014; 145(3):473-9 [PubMed] Related Publications
BACKGROUND: The mutations in oncogenic genes, such as EGFR, ALK, BRAF, HER2, DDR2, RET, and AKT1, defined subsets of non-small cell lung cancers (NSCLCs) with potential sensitivity to targeted therapies. At present, the mutational spectrum, prevalence, and clinicopathologic characteristics in squamous cell carcinomas with minor (<10%) glandular component (SQCC-mGCs) are not well established.
METHODS: Three hundred ten surgically resected lung squamous cell carcinoma (SQCC) specimens were collected. The histology of all cases was reevaluated using hematoxylin-eosin and immunohistochemistry staining. EGFR, KRAS, HER2, BRAF, PIK3CA, AKT1, and DDR2 mutations, as well as ALK and RET rearrangements, were examined in 310 SQCCs by directed sequencing.
RESULTS: Ninety-five SQCC-mGCs (30.6%) and 215 pure SQCCs (69.4%) were identified. Of the 95 SQCC-mGCs, 26 (27.4%; 95% CI, 18.7%-37.4%) were found to harbor known oncogenic mutations, including 10 with EGFR, seven with KRAS, three with PIK3CA, one with BRAF, one with HER2, one each with EGFR/PIK3CA and KRAS/PIK3CA double mutations, and two with EML4-ALK fusions. Ten of 215 pure SQCCs (4.7%; 95% CI, 2.3%-8.4%) harbored mutations, including seven with PIK3CA, and each with AKT1, DDR2, and EGFR. No RET rearrangements were detected in SQCCs. SQCC-mGCs had a significantly higher rate of mutations in known oncogenic genes than that in pure SQCCs (27.4% vs 4.7%, P<.001). All KRAS mutations occurred in SQCC-mGCs.
CONCLUSIONS: Our results demonstrated that oncogenic mutations in EGFR, KRAS, BRAF, HER2, and ALK were extremely rare or absent in patients with pure SQCC, whereas SQCC-mGC had a relatively high frequency of EGFR, ALK, or KRAS mutations. Prospective identification of these known oncogenic mutations in SQCC-mGC before the initiation of treatment is an essential step to identify which patient could benefit from targeted therapies.

Minuti G, D'Incecco A, Cappuzzo F
Targeted therapy for NSCLC with driver mutations.
Expert Opin Biol Ther. 2013; 13(10):1401-12 [PubMed] Related Publications
INTRODUCTION: Activating mutations of the epidermal growth factor receptor (EGFR) gene and rearrangement of anaplastic lymphoma kinase (ALK) gene best illustrate the therapeutic relevance of molecular characterization in non-small cell lung cancer (NSCLC) patients. Several genetic aberrations with a potential prognostic or predictive role have been identified, mainly in adenocarcinoma subtype, including ROS1, RET, MET, HER2, BRAF and KRAS. More recently oncogenic drivers, such as DDR2, FGFR1 and PI3KCA, have been characterized in squamous cell lung carcinoma (SCC) and target agents are currently under evaluation. The aim of this review is to summarize the growing scenario of new targetable oncogenes in NSCLC.
AREAS COVERED: For this review article all published data on NSCLC genomic alterations, including the techniques employed for oncogenic drivers identification, the prevalence of each one in lung cancer subtypes, the preclinical data corroborating their role in tumorigenesis and the potential biological tailored agents tested and under evaluation were collected and analyzed using PubMed.
EXPERT OPINION: Oncogenic products represent reliable targets for drug therapy and the expanding knowledge of molecular pathways involved in lung tumorigenesis is resulting in a dramatic change of treatment strategies leading to an improvement in disease and symptom control, extending life duration and improving quality of life.

Oike T, Ogiwara H, Tominaga Y, et al.
A synthetic lethality-based strategy to treat cancers harboring a genetic deficiency in the chromatin remodeling factor BRG1.
Cancer Res. 2013; 73(17):5508-18 [PubMed] Related Publications
The occurrence of inactivating mutations in SWI/SNF chromatin-remodeling genes in common cancers has attracted a great deal of interest. However, mechanistic strategies to target tumor cells carrying such mutations are yet to be developed. This study proposes a synthetic-lethality therapy for treating cancers deficient in the SWI/SNF catalytic (ATPase) subunit, BRG1/SMARCA4. The strategy relies upon inhibition of BRM/SMARCA2, another catalytic SWI/SNF subunit with a BRG1-related activity. Immunohistochemical analysis of a cohort of non-small-cell lung carcinomas (NSCLC) indicated that 15.5% (16 of 103) of the cohort, corresponding to preferentially undifferentiated tumors, was deficient in BRG1 expression. All BRG1-deficient cases were negative for alterations in known therapeutic target genes, for example, EGFR and DDR2 gene mutations, ALK gene fusions, or FGFR1 gene amplifications. RNA interference (RNAi)-mediated silencing of BRM suppressed the growth of BRG1-deficient cancer cells relative to BRG1-proficient cancer cells, inducing senescence via activation of p21/CDKN1A. This growth suppression was reversed by transduction of wild-type but not ATPase-deficient BRG1. In support of these in vitro results, a conditional RNAi study conducted in vivo revealed that BRM depletion suppressed the growth of BRG1-deficient tumor xenografts. Our results offer a rationale to develop BRM-ATPase inhibitors as a strategy to treat BRG1/SMARCA4-deficient cancers, including NSCLCs that lack mutations in presently known therapeutic target genes.

D'Arcangelo M, D'Incecco A, Cappuzzo F
Rare mutations in non-small-cell lung cancer.
Future Oncol. 2013; 9(5):699-711 [PubMed] Related Publications
In the last decade, new insights in molecular biology have changed the therapeutic landscape of non-small-cell lung cancer. Since 2004, when activating mutations of the EGFR were firstly identified, several genetic aberrations have been discovered, mainly in adenocarcinoma. EGFR mutations are a relatively frequent event in non-small-cell lung cancer, generally consisting of exon 19 deletion or exon 21 substitution. In adenocarcinoma, additional rare mutations are detectable in the EGFR gene, as well as in other genes, including ALK, ROS1, RET, HER2 and BRAF. Recent studies in squamous cell carcinoma identified TP53 as the most frequent mutation, followed by additional more rare mutations, including PI3KCA, PTEN, DDR2 and FGFR. The aim of the present review is to analyze the potential prognostic and predictive role of rare mutations.

Bos M, Gardizi M, Schildhaus HU, et al.
Complete metabolic response in a patient with repeatedly relapsed non-small cell lung cancer harboring ROS1 gene rearrangement after treatment with crizotinib.
Lung Cancer. 2013; 81(1):142-3 [PubMed] Related Publications
A 55-year-old Caucasian woman with lung adenocarcinoma stage IV presented with repeated relapse after treatment with cytotoxic chemotherapy (carboplatin, gemcitabine, docetaxel, pemetrexed) and targeted agents (erlotinib, cetuximab, sunitinib). Comprehensive molecular diagnostics (EGFR-, ALK-, RAS-, BRAF-, PIK3CA-, HER2- and DDR2-aberrations) were performed and failed initially to detect any driver mutation. While the patient suffered from rapid deterioration of her general condition, in particular from progressive dyspnea due to lung metastases, we implemented screening for RET- and ROS1 translocations into our molecular diagnostic program based on recent reports of these new molecular subgroups in lung adenocarcinoma. On retesting the patient's tumor sample was found to harbor a ROS1-translocation. The patient was subsequently treated with crizotinib and experienced a pronounced clinical improvement corresponding to a complete metabolic response in (18)F-FDG-PET and a good and confirmed partial response in CT (RECIST 1.1). Our case exemplifies the need for rapid implementation of newly discovered rare genetic lung cancer subtypes in routine molecular diagnostics.

Oxnard GR, Binder A, Jänne PA
New targetable oncogenes in non-small-cell lung cancer.
J Clin Oncol. 2013; 31(8):1097-104 [PubMed] Free Access to Full Article Related Publications
The identification of oncogenic driver mutations underlying sensitivity to epidermal growth factor receptor and anaplastic lymphoma kinase tyrosine kinase inhibitors has led to a surge of interest in identifying additional targetable oncogenes in non-small-cell lung cancer. A number of new potentially oncogenic gene alterations have been characterized in recent years, including BRAF mutations, HER2 insertions, PIK3CA mutations, FGFR1 amplifications, DDR2 mutations, ROS1 rearrangements, and RET rearrangements. In this review, we will discuss the techniques used to discover each of these candidate oncogenes, the prevalence of each in non-small-cell lung cancer, the preclinical data supporting their role in lung cancer, and data on small molecular inhibitors in development.

José A, Sobrevals L, Miguel Camacho-Sánchez J, et al.
Intraductal delivery of adenoviruses targets pancreatic tumors in transgenic Ela-myc mice and orthotopic xenografts.
Oncotarget. 2013; 4(1):94-105 [PubMed] Free Access to Full Article Related Publications
Gene-based anticancer therapies delivered by adenoviruses are limited by the poor viral distribution into the tumor. In the current work we have explored the feasibility of targeting pancreatic tumors through a loco-regional route. We have taken advantage of the ductal network in the pancreas to retrogradelly inject adenoviruses through the common bile duct in two different mouse models of pancreatic carcinogenesis: The transgenic Ela-myc mice that develop mixed neoplasms displaying both acinar-like and duct-like neoplastic cells affecting the whole pancreas; and mice bearing PANC-1 and BxPC-3 orthotopic xenografts that constitute a model of localized human neoplastic tumors. We studied tumor targeting and the anticancer effects of newly thymidine kinase-engineered adenoviruses both in vitro and in vivo, and conducted comparative studies between intraductal or intravenous administration. Our data indicate that the intraductal delivery of adenovirus efficiently targets pancreatic tumors in the two mouse models. The in vivo application of AduPARTKT plus ganciclovir (GCV) treatment induced tumor regression in Ela-myc mice. Moreover, the intraductal injection of ICOVIR15-TKT oncolytic adenoviruses significantly improved mean survival of mice bearing PANC-1 and BxPC-3 pancreatic xenografts from 30 to 52 days and from 20 to 68 days respectively (p less than 0.0001) when combined with GCV. Of notice, both AduPARTKT and ICOVIR15-TKT antitumoral responses were stronger by ductal viral application than intravenously, in line with the 38-fold increase in pancreas transduction observed upon ductal administration. In summary our data show that cytotoxic adenoviruses retrogradelly injected to the pancreas can be a feasible approach to treat localized pancreatic tumors.

Poudel B, Yoon DS, Lee JH, et al.
Collagen I enhances functional activities of human monocyte-derived dendritic cells via discoidin domain receptor 2.
Cell Immunol. 2012 Jul-Aug; 278(1-2):95-102 [PubMed] Related Publications
We evaluated the involvement of collagen and their discoidin domain receptors (DDRs), DDR1 and DDR2, on the activation of human monocyte-derived dendritic cells (hDCs). DDR2 was markedly expressed on mature hDCs in comparison to immature ones. Collagen I enhanced the release of IL-12p40, TNF-α and IFN-γ by hDCs. Additionally, hDCs exhibited enhanced expression of costimulatory molecules, and potent functional activities which, in turn, has therapeutic value. Interestingly, DDR2 depletion showed decrease in capacity of hDCs to stimulate T cells proliferation, whereas DDR1 silencing had no significant affect. These data demonstrate that DDR2 enhances hDCs activation and contributes to their functional activities. In addition, application of collagen I treated dendritic cells (DCs) vaccine reduced tumor burden giving longer survival in melanoma mice. Our study suggests that collagen I may enhance functional activities of DCs in immune response.

Shelton P, Jaiswal AK
The transcription factor NF-E2-related factor 2 (Nrf2): a protooncogene?
FASEB J. 2013; 27(2):414-23 [PubMed] Free Access to Full Article Related Publications
The transcription factor Nrf2 is responsible for regulating a battery of antioxidant and cellular protective genes, primarily in response to oxidative stress. A member of the cap 'n' collar family of transcription factors, Nrf2 activation is tightly controlled by a series of signaling events. These events can be separated into the basal state, a preinduction response, gene induction, and finally a postinduction response, culminating in the restoration of redox homeostasis. However, despite the immensely intricate level of control the cellular environment imposes on Nrf2 activity, there are many opportunities for perturbations to arise in the signaling events that favor carcinogenesis and, therefore, implicate Nrf2 as both a tumor suppressor and a protooncogene. Herein, we highlight the ways in which Nrf2 is regulated, and discuss some of the Nrf2-inducible antioxidant (NQO1, NQO2, HO-1, GCLC), antiapoptotic (Bcl-2), metabolic (G6PD, TKT, PPARγ), and drug efflux transporter (ABCG2, MRP3, MRP4) genes. In addition, we focus on how Nrf2 functions as a tumor suppressor under normal conditions and how its ability to detoxify the cellular environment makes it an attractive target for other oncogenes either via stabilization or degradation of the transcription factor. Finally, we discuss some of the ways in which Nrf2 is being considered as a therapeutic target for cancer treatment.

Drilon A, Rekhtman N, Ladanyi M, Paik P
Squamous-cell carcinomas of the lung: emerging biology, controversies, and the promise of targeted therapy.
Lancet Oncol. 2012; 13(10):e418-26 [PubMed] Related Publications
Squamous-cell carcinomas of the lung (SQCLCs) are defined by unique clinicopathological and molecular characteristics that have evolved substantially over time. Historically, these neoplasms were the most common subtype of non-small-cell lung cancers and were regarded as central tumours with high molecular complexity without targetable genetic abnormalities. Today, the incidence of SQCLCs is surpassed by adenocarcinomas of the lung with a shift towards peripheral squamous tumours. Differential responses to cytotoxic and biological treatments have reshaped our approach to standard therapies. Additionally, evidence of unique biology has emerged with the discovery of SOX2 amplification, NFE2L2 and KEAP1 mutations, PI3K pathway changes, FGFR1 amplification, and DDR2 mutations. These discoveries have ushered in a new era of targeted therapeutic agents for patients with this disease. This Review draws attention to the distinct clinical and pathological characteristics of SQCLCs, summarises present experience with existing cytotoxic and targeted therapies, and discusses emerging treatments based on new insights into the biology of this disease.

An SJ, Chen ZH, Su J, et al.
Identification of enriched driver gene alterations in subgroups of non-small cell lung cancer patients based on histology and smoking status.
PLoS One. 2012; 7(6):e40109 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Appropriate patient selection is needed for targeted therapies that are efficacious only in patients with specific genetic alterations. We aimed to define subgroups of patients with candidate driver genes in patients with non-small cell lung cancer.
METHODS: Patients with primary lung cancer who underwent clinical genetic tests at Guangdong General Hospital were enrolled. Driver genes were detected by sequencing, high-resolution melt analysis, qPCR, or multiple PCR and RACE methods.
RESULTS: 524 patients were enrolled in this study, and the differences in driver gene alterations among subgroups were analyzed based on histology and smoking status. In a subgroup of non-smokers with adenocarcinoma, EGFR was the most frequently altered gene, with a mutation rate of 49.8%, followed by EML4-ALK (9.3%), PTEN (9.1%), PIK3CA (5.2%), c-Met (4.8%), KRAS (4.5%), STK11 (2.7%), and BRAF (1.9%). The three most frequently altered genes in a subgroup of smokers with adenocarcinoma were EGFR (22.0%), STK11 (19.0%), and KRAS (12.0%). We only found EGFR (8.0%), c-Met (2.8%), and PIK3CA (2.6%) alterations in the non-smoker with squamous cell carcinoma (SCC) subgroup. PTEN (16.1%), STK11 (8.3%), and PIK3CA (7.2%) were the three most frequently enriched genes in smokers with SCC. DDR2 and FGFR2 only presented in smokers with SCC (4.4% and 2.2%, respectively). Among these four subgroups, the differences in EGFR, KRAS, and PTEN mutations were statistically significant.
CONCLUSION: The distinct features of driver gene alterations in different subgroups based on histology and smoking status were helpful in defining patients for future clinical trials that target these genes. This study also suggests that we may consider patients with infrequent alterations of driver genes as having rare or orphan diseases that should be managed with special molecularly targeted therapies.

Ohashi K, Pao W
A new target for therapy in squamous cell carcinoma of the lung.
Cancer Discov. 2011; 1(1):23-4 [PubMed] Related Publications
Investigators report the identification of novel somatic mutations in the DDR2 kinase gene in squamous cell carcinoma of the lung. Cellular, biochemical, and human data suggest that tumor cells harboring DDR2 mutations have increased sensitivity to existing tyrosine kinase inhibitors, providing rationale for clinical trials of agents that inhibit DDR2 kinase in the disease.

Hammerman PS, Sos ML, Ramos AH, et al.
Mutations in the DDR2 kinase gene identify a novel therapeutic target in squamous cell lung cancer.
Cancer Discov. 2011; 1(1):78-89 [PubMed] Free Access to Full Article Related Publications
UNLABELLED: While genomically targeted therapies have improved outcomes for patients with lung adenocarcinoma, little is known about the genomic alterations which drive squamous cell lung cancer. Sanger sequencing of the tyrosine kinome identified mutations in the DDR2 kinase gene in 3.8% of squamous cell lung cancers and cell lines. Squamous lung cancer cell lines harboring DDR2 mutations were selectively killed by knock-down of DDR2 by RNAi or by treatment with the multi-targeted kinase inhibitor dasatinib. Tumors established from a DDR2 mutant cell line were sensitive to dasatinib in xenograft models. Expression of mutated DDR2 led to cellular transformation which was blocked by dasatinib. A squamous cell lung cancer patient with a response to dasatinib and erlotinib treatment harbored a DDR2 kinase domain mutation. These data suggest that gain-of-function mutations in DDR2 are important oncogenic events and are amenable to therapy with dasatinib. As dasatinib is already approved for use, these findings could be rapidly translated into clinical trials.
SIGNIFICANCE: DDR2 mutations are present in 4% of lung SCCs, and DDR2 mutations are associated with sensitivity to dasatinib. These findings provide a rationale for designing clinical trials with the FDA-approved drug dasatinib in patients with lung SCCs.

Lee NO, Park JW, Lee JA, et al.
Dual action of a selective cyclooxygenase-2 inhibitor on vascular endothelial growth factor expression in human hepatocellular carcinoma cells: novel involvement of discoidin domain receptor 2.
J Cancer Res Clin Oncol. 2012; 138(1):73-84 [PubMed] Related Publications
PURPOSE: Vascular endothelial growth factor (VEGF) greatly contributes to the progression of hepatocellular carcinoma (HCC). It is reported that a selective cyclooxygenase-2 (COX-2) inhibitor inhibits cellular proliferation and may attenuate VEGF expression in HCC. We propose that different cascades in the VEGF pathway respond to COX-2 inhibition, depending on the cell types.
METHODS: The six human HCC cell lines--Hep3B, SNU387, SNU182, SNU423, SNU449, and PLC/PRF5--were cultured under normoxic and hypoxic conditions. Cells were treated with a selective COX-2 inhibitor (NS-398) and discoidin domain receptor 2 (DDR2) siRNA, and microarray analysis was performed.
RESULTS: NS-398 inhibited HCC proliferation and decreased the expression level of VEGF in HCC cells only under normoxia conditions. In hypoxia conditions, VEGF expression level in Hep3B cell was suppressed, while that in SNU387 cell was increased by NS-398 (P < 0.001). The NS-398-induced increase in VEGF expression in SNU387 cell was associated with the up-regulation of the DDR2 gene. NS-398-treated SNU series cells and PLC/PRF5 cells displayed a robust increase in DDR2 mRNA expression. Also, transfection with DDR2 siRNA decreased the VEGF expression level of SNU387, 423, 449 cells under hypoxia conditions (P < 0.05). In vivo chromatin immunoprecipitation assay demonstrated that NS-398 induces the enhancement of HIF-1α binding on VEGF promoter, leading to the increase in VEGF gene expression in hypoxic conditions. There is strong evidence that it is related to the DDR2 gene expression in SNU387 cells.
CONCLUSION: These findings disclose a novel cell-dependent regulatory mechanism of VEGF involving DDR2 gene in HCC cells.

Zhao G, Chen J, Deng Y, et al.
Identification of NDRG1-regulated genes associated with invasive potential in cervical and ovarian cancer cells.
Biochem Biophys Res Commun. 2011; 408(1):154-9 [PubMed] Related Publications
N-myc downstream regulated gene 1 (NDRG1) is an important gene regulating tumor invasion. In this study, shRNA technology was used to suppress NDRG1 expression in CaSki (a cervical cancer cell line) and HO-8910PM (an ovarian cancer cell line). In vitro assays showed that NDRG1 knockdown enhanced tumor cell adhesion, migration and invasion activities without affecting cell proliferation. cDNA microarray analysis revealed 96 deregulated genes with more than 2-fold changes in both cell lines after NDRG1 knockdown. Ten common upregulated genes (LPXN, DDR2, COL6A1, IL6, IL8, FYN, PTP4A3, PAPPA, ETV5 and CYGB) and one common downregulated gene (CLCA2) were considered to enhance tumor cell invasive activity. BisoGenet network analysis indicated that NDRG1 regulated these invasion effector genes/proteins in an indirect manner. Moreover, NDRG1 knockdown also reduced pro-invasion genes expression such as MMP7, TMPRSS4 and CTSK. These results suggest that regulation of invasion and metastasis by NDRG1 is a highly complicated process.

Lin CC, Chen LC, Tseng VS, et al.
Malignant pleural effusion cells show aberrant glucose metabolism gene expression.
Eur Respir J. 2011; 37(6):1453-65 [PubMed] Related Publications
Malignant pleural effusion (MPE) accompanying lung adenocarcinoma indicates poor prognosis and early metastasis. This study aimed to identify genes related to MPE formation. Three tissue sample cohorts, seven from healthy lungs, 18 from stage I-III lung adenocarcinoma with adjacent healthy lung tissue and 13 from lung adenocarcinomas with MPE, were analysed by oligonucleotide microarray. The identified genes were verified by quantitative real-time PCR (qRT-PCR), immunohistochemical staining, and immunofluorescence confocal microscopy. 20 up- or down-regulated genes with a two-fold change in MPE cancer cells compared to healthy tissues were differentially expressed from early- to late-stage lung cancer. Of 13 genes related to cellular metabolism, aldolase A (ALDOA), sorbitol dehydrogenase (SORD), transketolase (TKT), and tuberous sclerosis 1 (TSC1) were related to glucose metabolism. qRT-PCR validated their mRNA expressions in pleural metastatic samples. Immunohistochemical staining confirmed aberrant TKT, ALDOA, and TSC1 expressions in tumour cells. Immunofluorescence confirmed TKT co-localisation and co-distribution of ALDOA with thyroid transcription factor 1-positive cancer cells. TKT regulated the proliferation, vascular endothelial growth factor secretion in vitro and in vivo vascular permeability of cancer cell. Glucose metabolic reprogramming by ALDOA, SORD, TKT and TSC1 is important in MPE pathogenesis.

Yuan W, Wu S, Guo J, et al.
Silencing of TKTL1 by siRNA inhibits proliferation of human gastric cancer cells in vitro and in vivo.
Cancer Biol Ther. 2010; 9(9):710-6 [PubMed] Related Publications
Tumorigenesis requires energy production via aerobic glycolysis (Warburg effect) in malignant tumors. Recent research has demonstrated that the pentose phosphate pathway (PPP) is augmented in some tumors, especially the non-oxidative part of the PPP which is controlled by transketolase (TKT) enzyme reactions. One TKT isoform, transketolase-like protein 1 (TKTL1), is specifically upregulated in different human cancers, and its overexpression predicts poor patient survival. To further define the function of in malignant progression, we employed the small interference RNA (siRNA) technique to knockdown gene expression of TKTL1 in the gastric cancer cell line AGS. We used TKTL1 siRNA to observe the effect of reduced TKTL1 expression on gastric cancer tumorigenesis in a nude mice xenograft model and on proliferation in vitro. Our results showed that the expression of double stranded RNA led to the efficient and specific inhibition of endogenous TKTL1 expression in AGS cells. In addition, the TKT activity was significantly deceased in the TKTL1 siRNA-treated AGS cells. TKTL1 suppression resulted in delayed cell proliferation in vitro. Furthermore, loss of TKTL1 inhibited the growth of AGS tumor xenografts. Altogether, our findings indicate that the specific inhibition of TKTL1 may be important therapeutically.

Schulz DM, Böllner C, Thomas G, et al.
Identification of differentially expressed proteins in triple-negative breast carcinomas using DIGE and mass spectrometry.
J Proteome Res. 2009; 8(7):3430-8 [PubMed] Related Publications
We compared the protein expression pattern of triple-negative breast carcinomas (HER2-, ER-, PR-) versus those being positive for HER2 and negative for the hormone receptors (HER2+, ER-, PR-) by 2-D DIGE and mass spectrometry. We obtained differential expression patterns for several glycolytic enzymes (as for example MDH2, PGK1, TKT, Aldolase1), cytokeratins (CK7, 8, 9, 14, 17, 19), further structure proteins (vimentin, fibronectin, L-plastin), for NME1-NME2, lactoferrin, and members of the Annexin family. Western blot analysis and immunohistochemistry were conducted to verify the results. The identified marker proteins may advance a more detailed characterization of triple-negative breast cancers and may contribute to the development of better treatment strategies.

Chen H, Yue JX, Yang SH, et al.
Overexpression of transketolase-like gene 1 is associated with cell proliferation in uterine cervix cancer.
J Exp Clin Cancer Res. 2009; 28:43 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Tumor cells need large energy and nucleic acids to proliferate and grow. For most of their energy needs, cancer cells depend more on glycolysis. For most of their nucleic acids needs, cancer cells depend more on the nonoxidative pathway of the pentose phosphate pathway. Transketolase(TKT) is a crucial enzyme in the nonoxidative pathway of the PPP.
METHODS: The real-time quantity PCR was used to determine the expression of transketolase gene family in uterine cervix cancer. Transketolase activity of cell was determined by using enzyme-linked method. Cell proliferation was detected by using MTT.
RESULTS: The TKTL1 mRNA was specifically over-expressed in uterine cervix cancer cells(HeLa cell line) compare with normal human endocervical epithelial cells(End1/E6E7 cell line)(P < 0.05), whereas the expression of TKT and transketolase-like gene 2(TKTL2) have no significant differences between the two cell lines(P > 0.05). Moreover, we found that total transketolase activity was significantly reduced, and cell proliferation was remarkably inhibited after anti-TKTL1 siRNA treatment in HeLa cells. The total transketolase activity and cell proliferation have no significant differences after anti-TKTL1 siRNA treatment in End1/E6E7 cells.
CONCLUSION: These results indicate that TKTL1 plays an important role in total transketolase activity and cells proliferation in uterine cervix cancer.

Maeyama M, Koga H, Selvendiran K, et al.
Switching in discoid domain receptor expressions in SLUG-induced epithelial-mesenchymal transition.
Cancer. 2008; 113(10):2823-31 [PubMed] Related Publications
BACKGROUND: Acquired features of cells under epithelial-mesenchymal transition (EMT) have not yet been fully identified. The current study was conducted to assess alterations in both the proliferative potential and the responsiveness to extracellular matrices (ECMs) in EMT.
METHODS: MDCK cells and SLUG-transfected MDCK clones (SLUG-MDCK) were used in this study. The cell cycle was analyzed by using flow cytometry and Western blotting. ECM-stimulated cell proliferation was examined by using the following ECMs, type I collagen, type IV collagen, fibronectin, and laminin. Protein phosphorylation was detected by immunoprecipitation-Western by using the 4G10 antibody.
RESULTS: Both G1 and G2/M arrest were found in the SLUG-MDCK cells, and the responsible molecules for the cell-cycle arrests were, at least in part, p21WAF1/Cip1 and Wee1. Once in contact with type I collagen, the SLUG-MDCK cells, showing the Wee1 degradation, dramatically started to proliferate up to 6-fold in cell number at Day 5, in contrast to only a 2-fold increase in the control. The analysis of the collagen receptors in the SLUG-MDCK cells disclosed a striking increase in the discoid domain receptor (DDR) 2 expression and a clear decrease in the DDR1 expression. The immunoprecipitated DDR2 protein extracted from SLUG-MDCK cells, which were cultured on collagen for 30 minutes, was tyrosine-phosphorylated, indicating valid functionality of the up-regulated receptor. The altered expression from DDR1 to DDR2 was also found in the naturally dedifferentiated sister cell lines of human liver cancer.
CONCLUSIONS: Collectively, SLUG-induced EMT may alter the expression profile of receptor tyrosine kinases, including DDRs.

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