Cell Surface Receptor Tyrosine Kinases Research Articles

Abstract 1056: Potent in vivo anti-tumor activity of D-1553 as a single agent and in combination with targeted therapeutics in a broad spectrum of patient-derived xenograft tumor models with KRas G12C mutation

Abstract Ras protein plays a critical role in cell growth and proliferation by transmitting signal from cell surface receptor tyrosine kinase to downstream cellular proteins such as RAF and MEK. KRas is one of the most frequently mutated oncogenes, with mutations at residues G12, G13, and Q61, found in lung, colon, pancreatic and other solid malignancies. We have developed an orally bioavailable, covalent inhibitor of KRas G12C, D-1553, with potent in vitro biochemical, cellular activity and in vivo efficacy. Here we report the efficacy of D-1553 in a large panel of patient-derived xenograft (PDX) tumor models with KRas G12C mutation. In the lung cancer PDX models, D-1553 exhibited tumor growth inhibition (TGI) from 43.6% to 124.3%, with 4 out of 8 models showing tumor regression. In the colorectal cancer PDX models, the range of TGI was from 60.9% to 105.7%, with 3 out of 9 models showing regression. Combination treatment of D-1553 with chemotherapy and targeted agents demonstrated enhanced anti-tumor activity resulting in more tumor regression compared to single agent treatment. These observations from PDX models support the combination treatment as a key to increased overall response rate to KRas G12C inhibitor in clinical trial. D-1553 is currently in a Phase 1/2 clinical trial for patients with advanced solid tumors harboring KRas G12C mutation (NCT04585035). Citation Format: Zhe Shi, Jifang Weng, Xiaochong Fan, Qingqing Zhu, Emily Robb, Alyssa Moriarty, Michael Wick, Yueheng Jiang, Ling Zhang, Xing Dai, Yaolin Wang. Potent in vivo anti-tumor activity of D-1553 as a single agent and in combination with targeted therapeutics in a broad spectrum of patient-derived xenograft tumor models with KRas G12C mutation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1056.

Identification of Early Diagnostic and Prognostic Biomarkers via WGCNA in Stomach Adenocarcinoma.

Stomach adenocarcinoma (STAD) is a leading cause of cancer deaths, and the outcome of the patients remains dismal for the lack of effective biomarkers of early detection. Recent studies have elucidated the landscape of genomic alterations of gastric cancer and reveal some biomarkers of advanced-stage gastric cancer, however, information about early-stage biomarkers is limited. Here, we adopt Weighted Gene Co-expression Network Analysis (WGCNA) to screen potential biomarkers for early-stage STAD using RNA-Seq and clinical data from TCGA database. We find six gene clusters (or modules) are significantly correlated with the stage-I STADs. Among these, five hub genes, i.e., MS4A1, THBS2, VCAN, PDGFRB, and KCNA3 are identified and significantly de-regulated in the stage-I STADs compared with the normal stomach gland tissues, which suggests they can serve as potential early diagnostic biomarkers. Moreover, we show that high expression of VCAN and PDGFRB is associated with poor prognosis of STAD. VCAN encodes a large chondroitin sulfate proteoglycan that is the main component of the extracellular matrix, and PDGFRB encodes a cell surface tyrosine kinase receptor for members of the platelet-derived growth factor (PDGF) family. Consistently, Gene Ontology (GO) analysis of differentially expressed genes in the STADs indicates terms associated with extracellular matrix and receptor ligand activity are significantly enriched. Protein-protein network interaction analysis (PPI) and Gene Set Enrichment Analysis (GSEA) further support the core role of VCAN and PDGFRB in the tumorigenesis. Collectively, our study identifies the potential biomarkers for early detection and prognosis of STAD.

In Memoriam: José Baselga's Journey in Cancer Medicine.

In Memoriam: José Baselga's Journey in Cancer Medicine.

ST6Gal1 targets the ectodomain of ErbB2 in a site-specific manner and regulates gastric cancer cell sensitivity to trastuzumab

The clinical performance of the therapeutic monoclonal antibody trastuzumab in the treatment of ErbB2-positive unresectable gastric cancer (GC) is severely hampered by the emergence of molecular resistance. Trastuzumab’s target epitope is localized within the extracellular domain of the oncogenic cell surface receptor tyrosine kinase (RTK) ErbB2, which is known to undergo extensive N-linked glycosylation. However, the site-specific glycan repertoire of ErbB2, as well as the detailed molecular mechanisms through which specific aberrant glycan signatures functionally impact the malignant features of ErbB2-addicted GC cells, including the acquisition of trastuzumab resistance, remain elusive. Here, we demonstrate that ErbB2 is modified with both α2,6- and α2,3-sialylated glycan structures in GC clinical specimens. In-depth mass spectrometry-based glycomic and glycoproteomic analysis of ErbB2’s ectodomain disclosed a site-specific glycosylation profile in GC cells, in which the ST6Gal1 sialyltransferase specifically targets ErbB2 N-glycosylation sites occurring within the receptor’s trastuzumab-binding domain. Abrogation of ST6Gal1 expression reshaped the cellular and ErbB2-specific glycomes, expanded the cellular half-life of the ErbB2 receptor, and sensitized ErbB2-dependent GC cells to trastuzumab-induced cytotoxicity through the stabilization of ErbB dimers at the cell membrane, and the decreased activation of both ErbB2 and EGFR RTKs. Overall, our data demonstrates that ST6Gal1-mediated aberrant α2,6-sialylation actively tunes the resistance of ErbB2-driven GC cells to trastuzumab.

Exostosin‐like 2 Abrogation Promotes Heparan Sulfate Biosynthesis and Switches Cancer Cell Signalling Towards an Invasive Phenotype

Heparan Sulfate ProteoGlycans (HSPGs) are essential components of cells’ glycocalyx and Extracellular Matrix (ECM), which play key roles in cell physiology and in pathological scenarios. By binding to multiple biological ligands, via HS glycosaminoglycan (GAG) chains, HSPGs modulate cancer cells’ interaction with ECM and signalling networks, ultimately controlling tumour microenvironment and disease development. The aim of this work was to disclose the regulatory mechanisms underlying HSPGs biosynthetic pathways in gastric cancer context. Furthermore, we evaluated the impact of cellular GAGs content in cancer cell signalling and motility features. We developed glycoengineered gastric cancer cell models lacking specific glycosyltransferases involved in HS biosynthesis, Exostosin Like Glycosyltransferase 2 (EXTL2) and EXTL3. Biochemical characterization revealed that abrogation of EXTL2 or EXTL3 impacts both HS and Chondroitin Sulfate (CS) cell levels, as well as GAGs structural conformations, supporting that both enzymes exert broad regulatory roles in GAGs biosynthesis pathways. We observed that while EXTL3 is key for initiating the synthesis of HS chains, in detriment of CS biosynthesis, EXTL2 functions as a negative regulator of HS biosynthesis. Gene expression and protein levels of two major HS carriers were also determined and revealed that EXTL2 KO promoted significant alterations in HSPG core protein levels. Furthermore, we addressed the effects of aberrant GAGosylation over tumour cells motility and signalling events. Cellular functional analysis demonstrated that EXTL2 KO and concomitant HS increase promoted motile and invasive phenotypes, as well as the activation of key cell surface receptor tyrosine kinase. Overall, our results reveal the crucial roles of EXTL2 and EXTL3 in the modulation of proteoglycans expression and aberrant glycosylation profiles displayed by cancer cells, and the functional impact of these alterations on cells malignant behaviour, further supporting the clinical potential of HS biosynthetic machinery in cancer therapy.

Bone marrow-derived AXL tyrosine kinase promotes mitogenic crosstalk and cardiac allograft vasculopathy

Cardiac Allograft Vasculopathy (CAV) is a leading contributor to late transplant rejection. Although implicated, the mechanisms by which bone marrow-derived cells promote CAV remain unclear. Emerging evidence implicates the cell surface receptor tyrosine kinase AXL to be elevated in rejecting human allografts. AXL protein is found on multiple cell types, including bone marrow-derived myeloid cells. The causal role of AXL from this compartment and during transplant is largely unknown. This is important because AXL is a key regulator of myeloid inflammation. Utilizing experimental chimeras deficient in the bone marrow-derived Axl gene, we report that Axl antagonizes cardiac allograft survival and promotes CAV. Flow cytometric and histologic analyses of Axl-deficient transplant recipients revealed reductions in both allograft immune cell accumulation and vascular intimal thickness. Co-culture experiments designed to identify cell-intrinsic functions of Axl uncovered complementary cell-proliferative pathways by which Axl promotes CAV-associated inflammation. Specifically, Axl-deficient myeloid cells were less efficient at increasing the replication of both antigen-specific T cells and vascular smooth muscle cells (VSMCs), the latter a key hallmark of CAV. For the latter, we discovered that Axl-was required to amass the VSMC mitogen Platelet-Derived Growth Factor. Taken together, our studies reveal a new role for myeloid Axl in the progression of CAV and mitogenic crosstalk. Inhibition of AXL-protein, in combination with current standards of care, is a candidate strategy to prolong cardiac allograft survival.

Physical and Functional Interactome Atlas of Human Receptor Tyrosine Kinases

Much of cell-to-cell communication is facilitated via cell surface receptor tyrosine kinases (RTKs). These proteins phosphorylate their downstream cytoplasmic substrates in response to stimuli such as growth factors. Despite their central role, the functions for many RTKs are still poorly understood. To resolve the lack of systematic knowledge, we used three complementary methods to map the molecular context and substrate profiles of RTKs. We utilized AP-MS to characterize stable binding partners and RTK protein complexes, BioID to identify transient and proximal interactions, and an in-vitro kinase assay to identify substrates for RTKs. To identify how the kinase interactions are dependent on kinase activity, we also used kinase-deficient mutants. Our established data represents the first comprehensive, systemic mapping of RTK interactions and substrates. The resource adds information to the well-studied RTKs, offers insights into the function of the less-studied receptor tyrosine kinases, and highlights RTK-RTK interactions and shared signaling pathways.

An updated meta-analysis of the association between fibroblast growth factor receptor 4 polymorphisms and susceptibility to cancer.

Fibroblast growth factor receptor 4 (FGFR4) is a cell surface receptor tyrosine kinases (RTKs) for FGFs.Several studies have focused on the association between FGFR4 polymorphisms and cancer development. This meta-analysis aimed to estimate the association between FGFR4 rs351855 (Gly388Arg), rs1966265 (Val10Ile), rs7708357, rs2011077, and rs376618 polymorphisms and cancer risk. Eligible studies were identified from electronic databases. All statistical analyses were achieved with the STATA 14.0 software. Pooled odds ratios (ORs) with 95% confidence intervals (CIs) were used to quantitatively estimate the association. Overall, no significant association was found among rs351855, rs2011077, and rs376618 polymorphisms with the risk of overall cancer. The rs1966265 polymorphism significantly decreased the risk of cancer in recessive (OR = 0.87, 95% CI = 0.78–0.97, P=0.009, TT vs CT+CC) genetic model. Whereas the rs7708357 polymorphism was positively associated with cancer risk in dominant (OR = 1.17, 95% CI = 1.02–1.36, P=0.028) genetic model. Stratified analysis revealed that rs351855 variant significantly increased the risk of prostate cancer in heterozygous (OR = 1.16, 95% CI = 1.02–1.32, P=0.025 AG vs GG), dominant (OR = 1.20, 95% CI = 1.06–1.35, P=0.004, AG+AA vs GG), and allele (OR = 1.22, 95% CI = 1.06–1.41, P=0.005, A vs G) genetic models.In summary, the findings of this meta-analysis indicate that rs1966265, rs7708357, and rs351855 polymorphisms are correlated to cancer development. Further well-designed studies are necessary to draw more precise conclusions.

A Molecular Cascade Underlying Articular Cartilage Degeneration.

Preserving of articular cartilage is an effective way to protect synovial joints from becoming osteoarthritic (OA) joints. Understanding of the molecular basis of articular cartilage degeneration will provide valuable information in the effort to develop cartilage preserving drugs. There are currently no disease-modifying OA drugs (DMOADs) available to prevent articular cartilage destruction during the development of OA. Current drug treatments for OA focus on the reduction of joint pain, swelling, and inflammation at advanced stages of the disease. However, based on discoveries from several independent research laboratories and our laboratory in the past 15 to 20 years, we believe that we have a functional molecular understanding of articular cartilage degeneration. In this review article, we present and discuss experimental evidence to demonstrate a sequential chain of the molecular events underlying articular cartilage degeneration, which consists of transforming growth factor beta 1, high-temperature requirement A1 (a serine protease), discoidin domain receptor 2 (a cell surface receptor tyrosine kinase for native fibrillar collagens), and matrix metalloproteinase 13 (an extracellularmatrix degrading enzyme). If, as we strongly suspect, this molecular pathway is responsible for the initiation and acceleration of articular cartilage degeneration, which eventually leads to progressive joint failure, then these molecules may be ideal therapeutic targets for the development of DMOADs.

Abstract B67: EGFR as a target in pediatric solid tumors

Abstract The epidermal growth factor receptor (EGFR or HER1) is a cell surface tyrosine kinase receptor that is expressed in a diverse group of epithelial and nonepithelial tissues and broadly associated with cell proliferation and differentiation. Expression of wild-type EGFR and activating mutations are described in many malignancies, including a variety of pediatric solid tumors. In the setting of malignancy, EGFR has been associated with aggressive disease, chemotherapy resistance, and increased metastatic potential. Employment of anti-EGFR agents has yielded some promising results, but they are not always effective against all cancer-associated aberrant EGFR expression and are frequently associated with notable off-tumor toxicities due to the expression of EGFR in normal tissue. The unique EGFR monoclonal antibody (mAb) 806 selectively binds to an epitope on the extracellular portion of human EGFR expressed on the surface of tumor cells. This antibody recognizes the deletion mutant EGFRvIII commonly present in glioblastomas and some other solid tumors as well as wild-type EGFR. We designed a phase I trial for pediatric and young adult patients with recurrent or refractory solid tumors expressing epidermal growth factor (EGFR) to examine the safety and feasibility of administering autologous, peripheral blood-derived T cells that have been genetically modified to express a second-generation (2G) EGFR806-specific chimeric antigen receptor (CAR). Literature review and evaluation of EGFR immunohistochemistry (IHC) performed on several tissue microarrays were used to estimate the percentage of EGFR positivity among common subtypes of pediatric cancer. Using these tools, we hypothesized that 15-40% of otherwise eligible patients would meet the eligibility criteria of EGFR positivity. The trial opened in August of 2018. To date, a total of 33 patient tumors have undergone EGFR IHC to determine eligibility for the trial. 9/33 (27.3%) have been EGFR+. EGFR+ histologies include BCOR fusion sarcoma (3), germ cell tumor (2), osteosarcoma, Ewing sarcoma, desmoplastic small round cell tumor, and synovial sarcoma. Our eligibility testing thus far demonstrates EGFR expression by IHC in a variety of histologies. Two rare diseases, recurrent BCOR fusion sarcoma and refractory germ cell tumors, have demonstrated a significantly higher rate of EGFR IHC positivity, (3/3)100% and (2/3) 66.7%, respectively. These early results indicate that this trial and other anti-EGFR therapies may be most effectively targeted to certain subgroups of pediatric cancer patients. Citation Format: Catherine M. Albert, Navin R. Pinto, Erin R. Rudzinski, Julie R. Park. EGFR as a target in pediatric solid tumors [abstract]. In: Proceedings of the AACR Special Conference on the Advances in Pediatric Cancer Research; 2019 Sep 17-20; Montreal, QC, Canada. Philadelphia (PA): AACR; Cancer Res 2020;80(14 Suppl):Abstract nr B67.

Abstract A08: Development of FGFR4-specific chimeric antibody receptor (CAR) T cell and bispecific T cell engager (BiTE) for rhabdomyosarcoma (RMS) immunotherapy

Abstract Background: Despite decades of multimodule therapies, RMS remains incurable once it has metastasized; thus, new therapeutic strategies are warranted. FGFR4 is a developmentally regulated cell surface receptor tyrosine kinase, overexpressed in virtually all, mutationally activated in about 7.5% of RMS, and directly activated by PAX3-FOXO1 fusion protein, which makes it a tractable target for immunotherapy. Material and Methods: Using monoclonal antibody technologies and a yeast display B-cell library, we generated 15 human or mouse binders specific to human FGFR4 and engineered into human scFvFc. All binders were successfully produced in vitro, and we further characterized them using FACS and ELISA for their specificity. Octet was used to measure the binding affinity against human FGFR4. For those lead hits, they were made into different formats of therapeutic including CAR and BiTE. We then performed in vitro killing assays and/or in vivo xenograft model to determine the efficacy of those therapeutics in killing RMS cells. Results: m410 and m412 were two lead hits and scFvFcs of these two binders were successfully produced in vitro and showed FGFR4 specificity with a binding affinity at nanomolar concentration. By ELISA, these binders showed dose-dependent binding to FGFR4 protein but not to other FGFR family members. We then made m410 and m412 into CAR and BiTE format, respectively. T cells transduced with m410 CAR construct were found highly potent in inducing gamma interferon, TNF alpha, and cytotoxicity when the FGFR4-CART are cocultured with RMS cells. Our in vivo testing found them to be effective in eliminating RMS cells in murine xenograft models. When T cells were cocultured with RMS cells in the presence of m412 BiTE in vitro, potent selective antitumor effect was observed, suggesting this can be another promising strategy for RMS immunotherapy. Conclusions: Here our data demonstrated that we had successfully generated binders specific to human FGFR4. The CAR and BiTE developed from these binders were able to kill FGFR4-positive target cells. Our data suggest that these FGFR4 CARs and FGFR4 BiTEs could provide effective immune therapies for rhabdomyosarcoma and other FGFR4-expressing cancers. Citation Format: Adam Cheuk, Nityashree Shivaprasad, Dina Schneider, Marielle Yohe, Meijie Tan, Peter Azorsa, Ronald Sams, Silvia Pomella, Berkley Gryder, Rossella Rota, Ben Stanton, Jun Wei, Young Song, Xinyu Wen, Sivasish Sindiri, Jeetendra Kumar, Robert Hawley, Joon-Yong Chung, Doncho Zhelev, Zhongyu Zhu, Dimiter Dimitrov, Stephen Hewitt, Boro Dropulic, Rimas Orentas, Javed Khan. Development of FGFR4-specific chimeric antibody receptor (CAR) T cell and bispecific T cell engager (BiTE) for rhabdomyosarcoma (RMS) immunotherapy [abstract]. In: Proceedings of the AACR Special Conference on the Advances in Pediatric Cancer Research; 2019 Sep 17-20; Montreal, QC, Canada. Philadelphia (PA): AACR; Cancer Res 2020;80(14 Suppl):Abstract nr A08.

High expression of AMAP1, an ARF6 effector, is associated with elevated levels of PD-L1 and fibrosis of pancreatic cancer

BackgroundNot merely the onset of immune evasion, but other factors, such as acidosis and fibrosis, are also major barriers in cancer therapeutics. Dense fibrosis is a hallmark of pancreatic ductal carcinoma (PDAC), in which hyperactivation of focal adhesion kinase (FAK) in tumor cells was shown to be crucial. Double mutations of KRAS/ TP53 are characteristic to PDAC. We previously showed that high protein expression of ARF6 and its downstream effector AMAP1, as well as processes involved in the ARF6 activation by cell surface tyrosine kinase receptors, are major targets of the KRAS/TP53 mutations to promote PDAC invasion, metastasis, and immune evasion. This notion was recaptured by KPC mouse model of human PDAC (LSL-Kras(G12D/+); LSL-Trp53(R172H/+)); Pdx-1-Cre). Mechanistically, the ARF6-AMAP1 pathway is primarily involved in cellular dynamics of PD-L1, β1-integrins, and E-cadherin; and hence modulates cell-adhesion properties when ARF6 is activated. Here, with an aim to understand whether the ARF6-AMAP1 pathway is critically involved in the elevated levels of PD-L1 and fibrosis of PDAC, we analyzed relationship between AMAP1 and these malignant phenotypes. Moreover, because the ARF6 pathway may closely be related to focal adhesion dynamics and hence to FAK, we also investigated whether AMAP1 employs FAK in fibrosis.MethodsClinical specimens, as well as KPC cells/tumors and their shAMAP1 or shFAK derivatives were analyzed.ResultsElevated levels of PD-L1 and fibrosis correlated with poor outcome of our patient cohort, to be consistent with previous reports; in which high AMAP1 expression statistically correlated with the elevated PD-L1 and fibrosis. To be consistent, silencing of AMAP1 (shAMAP1) in KPC cells resulted in reduced PD-L1 expression and fibrosis in their tumors. On the other hand, shAMAP1 only slightly affected FAK activation in KPC cells, and phosphorylated FAK did not correlate with enhanced fibrosis or with poor outcome of our patients.ConclusionsTogether with our previous data, our results collectively indicated that the ARF6-AMAP1 pathway, empowered by the KRAS/TP53 mutations, is closely associated with elevated PD-L1 expression and fibrosis of human PDACs, to be recaptured in the KPC mouse model. The ARF6 pathway may promote fibrosis independent of FAK.2ZgVZH5hf3HfReDrMoiYXhVideo abstract

Cerebral arteriopathy associated with heterozygous variants in the casitas B-lineage lymphoma gene.

ObjectiveTo report a series of patients with cerebral arteriopathy associated with heterozygous variants in the casitas B-lineage lymphoma (CBL) gene and examine the functional role of the identified mutant Cbl protein. We hypothesized that mutated Cbl fails to act as a negative regulator of the RAS-mitogen-activated protein kinases (MAPK) signaling pathway, resulting in enhanced vascular fibroblast proliferation and migration and enhanced angiogenesis and collateral vessel formation.MethodsWe performed whole-exome sequencing in 11 separate families referred to Great Ormond Street Hospital, London, with suspected genetic cause for clinical presentation with severe progressive cerebral arteriopathy.ResultsWe identified heterozygous variants in the CBL gene in 5 affected cases from 3 families. We show that impaired CBL-mediated degradation of cell surface tyrosine kinase receptors and dysregulated intracellular signaling through the RAS-MAPK pathway contribute to the pathogenesis of the observed arteriopathy. Mutated CBL failed to control the angiogenic signal relay of vascular endothelial growth factor receptor 2, leading to prolonged tyrosine kinase signaling, thus driving angiogenesis and collateral vessel formation. Mutant Cbl promoted myofibroblast migration and proliferation contributing to vascular occlusive disease; these effects were abrogated following treatment with a RAF-RAS-MAPK pathway inhibitor.ConclusionsWe provide a possible mechanism for the arteriopathy associated with heterozygous CBL variants. Identification of the key role for the RAS-MAPK pathway in CBL-mediated cerebral arteriopathy could facilitate identification of novel or repurposed druggable targets for treating these patients and may also provide therapeutic clues for other cerebral arteriopathies.

Endosome-Localized Clathrin Adaptors AP-1 and GGA2 Support Cell Surface Expression of a Subset of RTKs for Cell Growth

The role of Golgi/endosome-localized clathrin adaptors in the maintenance of steady-state cell surface receptor tyrosine kinases (RTKs) is not well known. Here, we show that the epidermal growth factor receptor (EGFR), an RTK, associates preferentially with both AP-1 and GGA2 in vitro. AP-1 depletion reduces the expression of EGFR protein by promoting its lysosomal degradation. Proximity ligation assays demonstrated that the interaction of EGFR with AP-1 or GGA2 occurs in Rab11-positive recycling endosomes. Western blot analysis revealed that the depletion of AP-1 or GGA2 decreased surface expression of additional RTKs, such as Erb-B4 and MET. AP-1 depletion suppressed the growth of H1975 cancer cells and normal ARPE-19 cells. AP-1 was expressed in endosomes at high levels in several cancer tissues. Collectively, these results indicate that AP-1 and GGA2 function to retrieve a subset of RTKs in recycling endosomes, thereby sustaining their cell surface expression and, consequently, cancer cell growth.

Retrospective Analysis of Clinical Epidemiology in Gastrointestinal Stromal Tumour

Abstract Background Gastrointestinal Stromal tumors (GISTs) are the most common mesenchymal neoplasms of the gastrointestinal tract (GIT) i.e. sarcoma. GIST is classified into mutation in KIT (cluster of differentiation 117, CD117) oncogene (85%), Platelet — derived growth factor receptor alpha gene (PDGFRA) (10%) or rarely B-Raf gene. C.Kit - which is mutated & activated in 80% of GIST- is an oncogene which encodes cell surface receptor Tyrosine Kinase TK (CD 117) which is responsible for activation of multiple signaling cascades leading to cellular proliferation. Aim of the Work to explore the best management options of care for patients at Ain Shams University Hospitals (ASUH) by retrospectively analyzing epidemiological factors in Gastrointestinal stromal tumor patients and correlate them to clinical outcome; these factors are either patient or disease ones, while outcome include clinical benefits, survival and encountered toxicities. Patients and Methods this is a retrospective study. This study included 34 patients with GIST treated at the department of Clinical Oncology and Nuclear medicine, Ain Shams University between 2011 -2017 and followed up till 1-2017. Results many prognostic factors were selected for analysis to evaluate their impact on overall survival. Age, gender, site and size of tumor, mitotic index, histopathology, presence of metastasis at time of presentation and anemia all had no statistically significant impact on overall survival. Conclusion the prognosis of GIST is undoubtedly better than other sarcomas. No clear risk factor of GIST. Patient selection is paramount as to minimize the high cost of treatment. Tumor density must be known by Hounsfield unit before treatment to detect pseudo progression. Molecular analysis by PCR is very important to know sensitivity to treatment as a predictive biomarker. Patients should be kept on follow up for early detection of recurrence.

Expression of Alpha-type Platelet-derived Growth Factor Receptor–influenced Genes Predicts Clinical Outcome in Glioma

BACKGROUND: Alpha-type platelet-derived growth factor receptor (PDGFRα) is a cell surface tyrosine kinase receptor for members of the platelet-derived growth factor family. PDGFRα plays an important role in the regulation of several biological processes and contributes to the pathophysiology of a broad range of human cancers, including glioma. Here, we hypothesize that the genes directly or indirectly influenced by PDGFRα might be useful for prognosis in glioma. METHODS: By comparing the genome-wide gene expression pattern between PDGFRα+ and PDGFRα− cells from human oligodendrocyte progenitor, we defined the genes potentially influenced by PDGFRα. RESULTS: The PDGFRα-influenced genes are strongly associated with cancer-related pathways. We subsequently developed a prognostic gene signature derived from the PDGFRα-influenced genes. This gene signature is able to predict clinical outcome of glioma. This signature is also independent of traditional prognostic factors of glioma. Resampling tests indicate that the prognostic power of this gene signature outperforms random gene sets selected from human genome. More importantly, this signature is superior to the random gene signatures selected from glioma related genes. CONCLUSIONS: Despite the absence of clear elucidation of molecular mechanisms, this study suggests the vital role of PDGFRα in carcinogenesis. Furthermore, the PDGFRα-based gene signature provides a promising prognostic tool for glioma and validates PDGFRα as a novel and effective therapeutic target in human cancers.

MYO1D binds with kinase domain of the EGFR family to anchor them to plasma membrane before their activation and contributes carcinogenesis.

The cell surface receptor tyrosine kinase (RTK) exists in a dynamic state, however, it remains unknown how single membrane-spanning RTK proteins are retained in the plasma membrane before their activation. This study was undertaken to investigate how RTK proteins are anchored in the plasma membrane before they bind with their respective extracellular ligands for activation through protein-protein interaction, co-localization, and functional phenotype studies. Here we show that unconventional myosin-I MYO1D functions to hold members of the EGFR family (except ErbB3) at the plasma membrane. MYO1D binds only with unphosphorylated EGFRs and anchors them to underlying actin cytoskeleton at the plasma membrane. The C-terminal end region of the MYO1D tail domain containing a β-meander motif is critical for direct binding with kinase domain of the EGFR family, and expression of the tail domain alone suppresses the oncogenic action of full-length MYO1D. Overexpressed MYO1D increases colorectal and breast cancer cell motility and viability through upregulating EGFR level, and thereby promotes colorectal tumor progression in a syngeneic mouse model. MYO1D is upregulated in human colorectal cancer tissues from advanced stages. Collectively, molecular motor MYO1D plays a distinct role in the dynamic regulation of EGFR family levels by holding them at the plasma membrane before their activation. Overexpressed MYO1D contributes to colorectal carcinogenesis possibly as a novel oncogene and thus may serve as an additional target for suppression of RTK signaling in cancer treatment.

Epigenetic Dysregulation at the Crossroad of Women's Cancer.

An increasingly number of women of all age groups are affected by cancer, despite substantial progress in our understanding of cancer pathobiology, the underlying genomic alterations and signaling cascades, and cellular-environmental interactions. Though our understanding of women’s cancer is far more complete than ever before, there is no comprehensive model to explain the reasons behind the increased incidents of certain reproductive cancer among older as well as younger women. It is generally suspected that environmental and life-style factors affecting hormonal and growth control pathways might help account for the rise of women’s cancers in younger age, as well, via epigenetic mechanisms. Epigenetic regulators play an important role in orchestrating an orderly coordination of cellular signals in gene activity in response to upstream signaling and/or epigenetic modifiers present in a dynamic extracellular milieu. Here we will discuss the broad principles of epigenetic regulation of DNA methylation and demethylation, histone acetylation and deacetylation, and RNA methylation in women’s cancers in the context of gene expression, hormonal action, and the EGFR family of cell surface receptor tyrosine kinases. We anticipate that a better understanding of the epigenetics of women’s cancers may provide new regulatory leads and further fuel the development of new epigenetic biomarkers and therapeutic approaches.

Gas6/Axl signaling attenuates alveolar inflammation in ischemia-reperfusion-induced acute lung injury by up-regulating SOCS3-mediated pathway.

BackgroundAxl is a cell surface receptor tyrosine kinase, and activation of the Axl attenuates inflammation induced by various stimuli. Growth arrest-specific 6 (Gas6) has high affinity for Axl receptor. The role of Gas6/Axl signaling in ischemia-reperfusion-induced acute lung injury (IR-ALI) has not been explored previously. We hypothesized that Gas6/Axl signaling regulates IR-induced alveolar inflammation via a pathway mediated by suppressor of cytokine signaling 3 (SOCS3).MethodsIR-ALI was induced by producing 30 min of ischemia followed by 90 min of reperfusion in situ in an isolated and perfused rat lung model. The rats were randomly allotted to a control group and IR groups, which were treated with three different doses of Gas6. Mouse alveolar epithelium MLE-12 cells were cultured in control and hypoxia-reoxygenation (HR) conditions with or without Gas6 and Axl inhibitor R428 pretreatment.ResultsWe found that Gas6 attenuated IR-induced lung edema, the production of proinflammatory cytokines in perfusates, and the severity of ALI ex vivo. IR down-regulated SOCS3 expression and up-regulated NF-κB, and Gas6 restored this process. In the model of MLE-12 cells with HR, Gas6 suppressed the activation of TRAF6 and NF-κB by up-regulating SOCS3. Axl expression of alveolar epithelium was suppressed in IR-ALI but Gas6 restored phosphorylation of Axl. The anti-inflammatory effect of Gas6 was antagonized by R428, which highlighted that phosphorylation of Axl mediated the protective role of Gas6 in IR-ALI.ConclusionsGas6 up-regulates phosphorylation of Axl on alveolar epithelium in IR-ALI. The Gas6/Axl signaling activates the SOCS3-mediated pathway and attenuates IR-related inflammation and injury.

Targeting Discoidin Domain Receptor 2 for the Development of Disease-Modifying Osteoarthritis Drugs

One of the most pressing issues in osteoarthritis (OA) research is the development of disease-modifying OA drugs (DMOADs), as currently there are no such drugs available. The paucity of suitable DMOADs is mostly due to the lack of approved ideal therapeutic targets necessary for the development of these drugs. However, based on recent discoveries from our laboratory and other independent laboratories, it is indicated that a cell surface receptor tyrosine kinase for collagen type II, discoidin domain receptor 2 (DDR2), may be an ideal therapeutic target for the development of DMOADs. In this article, we review the current status of research in understanding roles of DDR2 in the development of OA.