Role Of ADAM17 Research Articles

The Pro-Adhesive and Reduced Angiogenic Properties of Endothelial Colony Forming Cells (ECFC) from JAK2V617F MPN Patients Are Not Related to the Expression of the JAK2 mutation in These Cells: A Potential Role of ADAM17

INTRODUCTION: JAK2V617F mutation is independently associated with a higher risk of venous thromboembolic events (VTE) in myeloproliferative neoplasms (MPN). We have previously shown that endothelial colony-forming cells (ECFCs) from JAK2V617F MPN patients do not express this mutation but exhibit a pro-adhesive phenotype with a lower in vitro angiogenic potential. Here, we explore the mechanisms through which ECFCs from JAK2V617F MPN patients behave differently from ECFCs from healthy individuals. METHODS: We selected 38 patients with newly or previously diagnosed MPN, regardless of current or prior hydroxyurea therapy, with or without a history of VTE. Plasma levels of ADAMTS13, P-selectin, soluble VCAM, soluble ICAM, PDGF-AA, PDGF-AB/BB, IL-8, IL-1β, and soluble CD40 ligand were measured through the use of a multiplex assay. We then tried to isolate ECFCs from 20 of the JAK2V617F patients as well as 14 healthy individuals. Successfully isolated ECFCs were then submitted to co-culture with red blood cells (RBC), after which RNA was extracted from ECFCs. ADAMTS13, P-selectin, sVCAM, and sICAM were measured in the supernatant from ECFCs and RBC co-culture with multiplex assay. ECFCs' surface expression of P-selectin, VCAM, ICAM, and E-selectin was measured with the use of flow cytometry. Gene expression in RNA from co-cultured ECFCs was assessed with two 84-gene RT-PCR arrays for endothelial cell biology and signal transduction pathways (RT2 Profiler PCR array, Qiagen®). RESULTS: Recruited patients had polycythemia vera (PV) (n=17), primary myelofibrosis (PMF) (n=7) and essential thrombocythemia (ET) (n=14); 34% of them had had a previous VTE (6/17 PV; 3/14 ET and 4/7 PMF). Median age was 59 years (26-88), 23% were male. Compared with JAK2wt, JAK2V617F MPN patients (n=29) showed higher median concentrations of sVCAM (1063 vs. 786.5 ng/ml, p=0.0315), sCD40L (339 vs. 166.4 ng/ml, p=0.0065), PDGF-AA (430.6 vs. 136.5 ng/ml, p=0.03) and PDGF-AB/BB (1068 vs. 365.8 ng/ml, p=0.004). Success in ECFC isolation was 9/20 (45%) in JAK2V617F MPN patients and 8/14 (57%) in healthy individuals. None of the ECFCs from JAK2V617F MPN patients expressed this mutation. In comparison with ECFCs from healthy individuals, ECFCs from JAK2V617F MPN patients did not show a higher expression of either VCAM1, ICAM, P-selectin, and E-selectin, as measured by flow cytometry after co-culture with RBCs. Multiplex assay on the supernatant of this co-culture did not show any difference in the levels of ADAMTS13, sVCAM, sICAM, and sP-selectin. RNA PCR array from the ECFCs after co-culture with RBCs showed no difference in the expression of adhesion molecules when compared with ECFCs from healthy individuals, except for the increased expression of ADAM17 (fold regulation: 5.46, p=0.006), a metalloprotease involved in the shedding of adhesion molecules, among them VCAM1. ECFCs from MPN patients did not show higher activation of the JAK-STAT pathway but had a lower expression of WNT5 (fold regulation: -2.22, p=0.03), indicating a reduced activation of the Hedgehog pathway, suitable with the reduced in vitro angiogenesis capacity of these cells. CONCLUSIONS: JAK2V617F MPNs are associated with an increase in circulating adhesion molecules, such as sVCAM, and platelet activation markers. The pro-adhesive phenotype and lower angiogenic potential of ECFCs JAK2V617F MPN patients are not related to this mutation, which is not expressed in these cells and might be related to an increased expression of ADAM17 and reduced activation of the Hedgehog pathway. Disclosures Ozelo: BioMarin: Research Funding; Pfizer: Research Funding; Takeda: Research Funding; Novo Nordisk: Research Funding; Roche: Research Funding.

The Role of ADAM15 in Lung Cancer Progression

The Role of ADAM15 in Lung Cancer Progression

The ADAM17 protease promotes tobacco smoke carcinogen-induced lung tumorigenesis.

Lung cancer is the leading cause of cancer-related mortality, with most cases attributed to tobacco smoking, in which nicotine-derived nitrosamine ketone (NNK) is the most potent lung carcinogen. The ADAM17 protease is responsible for the ectodomain shedding of many pro-tumorigenic cytokines, growth factors and receptors, and therefore is an attractive target in cancer. However, the role of ADAM17 in promoting tobacco smoke carcinogen-induced lung carcinogenesis is unknown. The hypomorphic Adam17ex/ex mice-characterized by reduced global ADAM17 expression-were backcrossed onto the NNK-sensitive pseudo-A/J background. CRISPR-driven and inhibitor-based (GW280264X, and ADAM17 prodomain) ADAM17 targeting was employed in the human lung adenocarcinoma cell lines A549 and NCI-H23. Human lung cancer biopsies were also used for analyses. The Adam17ex/ex mice displayed marked protection against NNK-induced lung adenocarcinoma. Specifically, the number and size of lung lesions in NNK-treated pseudo-A/J Adam17ex/ex mice were significantly reduced compared with wild-type littermate controls. This was associated with lower proliferative index throughout the lung epithelium. ADAM17 targeting in A549 and NCI-H23 cells led to reduced proliferative and colony-forming capacities. Notably, among select ADAM17 substrates, ADAM17 deficiency abrogated shedding of the soluble IL-6 receptor (sIL-6R), which coincided with the blockade of sIL-6R-mediated trans-signaling via ERK MAPK cascade. Furthermore, NNK upregulated phosphorylation of p38 MAPK, whose pharmacological inhibition suppressed ADAM17 threonine phosphorylation. Importantly, ADAM17 threonine phosphorylation was significantly upregulated in human lung adenocarcinoma with smoking history compared with their cancer-free controls. Our study identifies the ADAM17/sIL-6R/ERK MAPK axis as a candidate therapeutic strategy against tobacco smoke-associated lung carcinogenesis.

Functional Characterization of Colon Cancer-Associated Mutations in ADAM17: Modifications in the Pro-Domain Interfere with Trafficking and Maturation.

Colorectal cancer is one of the most commonly diagnosed malignancies in the Western world and is associated with elevated expression and activity of epidermal growth factor receptors (EGF-R). The metalloproteinase ADAM17 is involved in EGF-R activation by processing EGF-R ligands from membrane-bound pro-ligands. Underlining the link between colon cancer and ADAM17, genetic intestinal cancer models in ADAM17-deficient mice show a reduced tumor burden. In this study, we characterize point mutations within the ADAM17 gene found in the tissue of colon cancer patients. In order to shed light on the role of ADAM17 in cancer development, as well as into the mechanisms that regulate maturation and cellular trafficking of ADAM17, we here perform overexpression studies of four ADAM17 variants located in the pro-, membrane-proximal- and cytoplasmic-domain of the ADAM17 protein in ADAM10/17-deficient HEK cells. Interestingly, we found a cancer-associated point mutation within the pro-domain of ADAM17 (R177C) to be most impaired in its proteolytic activity and trafficking to the cell membrane. By comparing this variant to an ADAM17 construct lacking the entire pro-domain, we discovered similar functional limitations and propose a crucial role of the pro-domain for ADAM17 maturation, cellular trafficking and thus proteolytic activity.

Impaired mechanical, heat, and cold nociception in a murine model of genetic TACE/ADAM17 knockdown.

TNF-α-converting enzyme, a member of the ADAM (A disintegrin and metalloproteinase) protease family and also known as ADAM17, regulates inflammation and regeneration in health and disease. ADAM17 targets are involved in pain development and hypersensitivity in animal models of inflammatory and neuropathic pain. However, the role of ADAM17 in the pain pathway is largely unknown. Therefore, we used the hypomorphic ADAM17 (ADAM17ex/ex) mouse model to investigate the importance of ADAM17 in nociceptive behavior, morphology, and function of primary afferent nociceptors. ADAM17ex/ex mice were hyposensitive to noxious stimulation, showing elevated mechanical thresholds as well as impaired heat and cold sensitivity. Despite these differences, skin thickness and innervation were comparable to controls. Although dorsal root ganglia of ADAM17ex/ex mice exhibited normal morphology of peptidergic and nonpeptidergic neurons, a small but significant reduction in the number of isolectin β-4–positive neurons was observed. Functional electrical properties of unmyelinated nociceptors showed differences in resting membrane potential, afterhyperpolarization, and firing patterns in specific subpopulations of sensory neurons in ADAM17ex/ex mice. However, spinal cord morphology and microglia activity in ADAM17ex/ex mice were not altered. Our data suggest that ADAM17 contributes to the processing of painful stimuli, with a complex mode of action orchestrating the function of neurons along the pain pathway.—Quarta, S., Mitrić, M., Kalpachidou, T., Mair, N., Schiefermeier-Mach, N., Andratsch, M., Qi, Y., Langeslag, M., Malsch, P., Rose-John, S., Kress, M. Impaired mechanical, heat, and cold nociception in a murine model of genetic TACE/ADAM17 knockdown.

Cleavage of the extracellular domain of junctional adhesion molecule-A is associated with resistance to anti-HER2 therapies in breast cancer settings

BackgroundJunctional adhesion molecule-A (JAM-A) is an adhesion molecule whose overexpression on breast tumor tissue has been associated with aggressive cancer phenotypes, including human epidermal growth factor receptor-2 (HER2)-positive disease. Since JAM-A has been described to regulate HER2 expression in breast cancer cells, we hypothesized that JAM-dependent stabilization of HER2 could participate in resistance to HER2-targeted therapies.MethodsUsing breast cancer cell line models resistant to anti-HER2 drugs, we investigated JAM-A expression and the effect of JAM-A silencing on biochemical/functional parameters. We also tested whether altered JAM-A expression/processing underpinned differences between drug-sensitive and -resistant cells and acted as a biomarker of patients who developed resistance to HER2-targeted therapies.ResultsSilencing JAM-A enhanced the anti-proliferative effects of anti-HER2 treatments in trastuzumab- and lapatinib-resistant breast cancer cells and further reduced HER2 protein expression and Akt phosphorylation in drug-treated cells. Increased epidermal growth factor receptor expression observed in drug-resistant models was normalized upon JAM-A silencing. JAM-A was highly expressed in all of a small cohort of HER2-positive patients whose disease recurred following anti-HER2 therapy. High JAM-A expression also correlated with metastatic disease at the time of diagnosis in another patient cohort resistant to trastuzumab therapy. Importantly, cleavage of JAM-A was increased in drug-resistant cell lines in conjunction with increased expression of ADAM-10 and -17 metalloproteases. Pharmacological inhibition or genetic silencing studies suggested a particular role for ADAM-10 in reducing JAM-A cleavage and partially re-sensitizing drug-resistant cells to the anti-proliferative effects of HER2-targeted drugs. Functionally, recombinant cleaved JAM-A enhanced breast cancer cell invasion in vitro and both invasion and proliferation in a semi-in vivo model. Finally, cleaved JAM-A was detectable in the serum of a small cohort of HER2-positive patients and correlated significantly with resistance to HER2-targeted therapy.ConclusionsCollectively, our data suggest a novel model whereby increased expression and cleavage of JAM-A drive tumorigenic behavior and act as a biomarker and potential therapeutic target for resistance to HER2-targeted therapies.

The emerging role of ADAM metalloproteinases in immunity.

Proteolysis is an irreversible physiological process that can result in the termination or activation of protein function. Many transmembrane proteins that are involved in the cellular communication between immune cells and structural cells - for example, Notch, CD23, CD44, and membrane-anchored cytokines and their receptors - are cleaved by the ADAM (a disintegrin and metalloproteinase) family of enzymes. Here, we review recent insights into the molecular activation, substrate specificity and function of ADAM proteins in the development and regulation of the immune system, with a particular focus on the roles of ADAM10 and ADAM17.

Abstract 542: A disintergrin and metalloprotease (ADAM) 15 promotes non-small cell lung cancer (NSCLC) proliferation through cytosolic domain, not extra-cytosolic metalloprotease activity

Abstract Emerging evidence indicates that proteins of a disintergrin and metalloprotease (ADAM) family contribute to cancer progression and metastasis. ADAM15 is up-regulated in multiple cancers and the enzymatic activities of its extracellular metalloprotrease domain promote cancer proliferation and migration by mediating the ErbB signaling pathway. In lung cancer, the enzymatic activity of ADAM15 extracellular domain is reported to be independent of ErbB signaling, indicating an alternative mechanism in promoting lung cancer progression. However, the role of ADAM15 in non-small cell lung cancer (NSCLC) and its correlation to patient prognosis is not well understood. This study demonstrated the longest ADAM15 isoforms, isoform 6 (i6), which contained the most cytoplasmic Src homology 3 (SH3) binding motifs, was significantly up-regulated in progressive NSCLC cell. Comparison of i6 and isoform 1 (i1) revealed that the cytoplasmic domain was essential for NSCLC cell proliferation and aggressiveness. ADAM15 i6, but not i1, mediated the activation the activation of the Src homolog 2 domain containing (Shc) through physical interaction with growth factor receptor-bound protein 2 (Grb2). ADAM15 i6 overexpression promoted NSCLC cell growth in a xenograft mouse model, while ADAM15 or Grb2 knockdown resulted in tumor shrinkage. ADAM15 was overexpressed in primary NSCLC tissues compared to adjacent normal tissues. Patients with ADAM15 i6 high-expressing lung tumors had shorter survival times. Thus, a novel mechanism of the ADAM15 cytoplasmic domain is identified in NSCLC tumor progression. This may help shed light on the molecular mechanisms of ADAM proteins and facilitate development of novel therapy for NSCLC. Citation Format: Hsin-Han Hou. A disintergrin and metalloprotease (ADAM) 15 promotes non-small cell lung cancer (NSCLC) proliferation through cytosolic domain, not extra-cytosolic metalloprotease activity [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 542.

The role of ADAM17 in the T-cell response against bacterial pathogens.

ADAM17 is a member of the A Disintegrin And Metalloproteinase family of proteases. It is ubiquitously expressed and causes the shedding of a broad spectrum of surface proteins such as adhesion molecules, cytokines and cytokine receptors. By controlled shedding of these proteins from leukocytes, ADAM17 is able to regulate immune responses. Several ADAM17 targets on T cells have been implicated in T-cell migration, differentiation and effector functions. However, the role of ADAM17 in T-cell responses is still unclear. To characterize the function of ADAM17 in T cells, we used Adam17fl/fl×CD4cre+ mice with a T-cell restricted inactivation of the Adam17 gene. Upon stimulation, ADAM17-deficient CD4+ and CD8+ T cells were impaired in shedding of CD62L, IL-6Rα, TNF-α, TNFRI and TNFRII. Surprisingly, we could not detect profound changes in the composition of major T-cell subsets in Adam17fl/fl×CD4cre+ mice. Following infection with Listeria monocytogenes, Adam17fl/fl×CD4cre+ mice mounted regular listeria-specific CD4+ TH1 and CD8+ T-cell responses and were able to control primary and secondary infections. In conclusion, our study indicates that ADAM17 is either not required in T cells under homoeostatic conditions and for control of listeria infection or can be effectively compensated by other mechanisms.

Role of ADAM10 in intestinal crypt homeostasis and tumorigenesis

A disintegrin and metalloproteinases (ADAMs) are a family of mSultidomain, membrane-anchored proteases that regulate diverse cellular functions, including cell adhesion, migration, proteolysis and other cell signaling events. Catalytically-active ADAMs act as ectodomain sheddases that proteolytically cleave type I and type II transmembrane proteins and some GPI-anchored proteins from the cellular surface. ADAMs can also modulate other cellular signaling events through a process known as regulated intramembrane proteolysis (RIP). Through their proteolytic activity, ADAMs can rapidly modulate key cell signaling pathways in response to changes in the extracellular environment (e.g. inflammation) and play a central role in coordinating intercellular communication. Dysregulation of these processes through aberrant expression, or sustained ADAM activity, is linked to chronic inflammation, inflammation-associated cancer and tumorigenesis. ADAM10 was the first disintegrin-metalloproteinase demonstrated to have proteolytic activity and is the prototypic ADAM associated with RIP activity (e.g. sequential Notch receptor processing). ADAM10 is abundantly expressed throughout the gastrointestinal tract and during normal intestinal homeostasis ADAM10 regulates many cellular processes associated with intestinal development, cell fate specification and maintenance of intestinal stem cell/progenitor populations. In addition, several signaling pathways that undergo ectodomain shedding by ADAM10 (e.g. Notch, EGFR/ErbB, IL-6/sIL-6R) help control intestinal injury/regenerative responses and may drive intestinal inflammation and colon cancer initiation and progression. Here, I review some of the proposed functions of ADAM10 associated with intestinal crypt homeostasis and tumorigenesis within the gastrointestinal tract in vivo. This article is part of a Special Issue entitled: Proteolysis as a Regulatory Event in Pathophysiology edited by Stefan Rose-John.

Abstract P151: Adam17 in the Paraventricular Nucleus Contributes to Activation of Pre-Autonomic Neurons and Maintenance of Baseline Blood Pressure

We previously reported that over-activation of the classical arm ( i.e. ACE/Ang-II/AT1 receptor) of the brain renin-angiotensin system (RAS) up-regulates ADAM17, a disintegrin and metalloprotease. ADAM17 cleaves angiotensin converting enzyme 2 (ACE2) from the cell surface, leading to a compromised compensatory RAS axis ( i.e. ACE2/Ang-(1-7)/Mas receptor) and neurogenic hypertension. We hypothesized that ADAM17 within the paraventricular nucleus of the hypothalamus (PVN) intrinsically regulate neuronal activity, thus contributing to sustained sympathetic drive and the development of neurogenic hypertension. To test this hypothesis, a new transgenic mouse line, named SAT, was generated to selectively knockdown ADAM17 in pre-autonomic Sim1 neurons within the PVN, using cre-loxP technology. Mean arterial pressure recorded in conscious mice (telemetry) showed a significant reduction at baseline (ΔMAP: -8 ±2 mmHg, N=3, P <0.05) and an increased vagal tone (Heart rate: 231 ±19 vs. 160 ±11 bpm, N=10, P<0.05) in SAT vs. control (NT) litter-mates. To address the impact of ADAM17 deletion on neuronal excitability, c-Fos immunohistochemistry was performed. SAT mice exhibited a significant reduction of c-Fos expression in the PVN compared to NT (14 ±2 vs. 124 ±8 neurons, N=3, P <0.001). Retrograde labeling (pseudorabies virus-eGFP) confirmed that a sub-population of these neurons projected to the kidney. In addition, mRNA expression of the GABAa receptor was higher in the hypothalamus of SAT compared to NT mice (1.3 ±0.1 vs. 1.0 ±0.1, N=7, P <0.05). ADAM17 knockdown from the PVN had a positive effect on the compensatory RAS, as evidenced by a rise in hypothalamic ACE2 activity compared to NT mice (82.3 ±4.2 vs. 69.7 ±3.3, N=7, P <0.05). Interestingly, this was also extended downstream of the PVN, with an increase in ACE2 activity (96.7 ± 3.8 vs. 82.0 ± 3.4, N=7, P <0.05), as well as Mas receptor gene expression (0.28 ±0.03 vs. 0.17 ± 0.01, N=6, P <0.01) in the brainstem of SAT compared to NT mice. Altogether, our data highlight a new role for ADAM17 in neuronal excitability and the maintenance of baseline blood pressure. Potential mechanisms opposing ADAM17-mediated neuronal excitability of PVN neurons include GABAergic pathways and the compensatory axis of the brain RAS.

9 - Proffered Paper: Role of ADAM17 in the non-cell autonomous effects of oncogene-induced senescence

9 - Proffered Paper: Role of ADAM17 in the non-cell autonomous effects of oncogene-induced senescence

Role of ADAM17 in the non-cell autonomous effects of oncogene-induced senescence.

IntroductionCellular senescence is a terminal cell proliferation arrest that can be triggered by oncogenes. One of the traits of oncogene-induced senescence (OIS) is the so-called senescence-associated secretory phenotype or senescence secretome. Depending on the context, the non-cell autonomous effects of OIS may vary from tumor suppression to promotion of metastasis. Despite being such a physiological and pathologically relevant effector, the mechanisms of generation of the senescence secretome are largely unknown.MethodsWe analyzed by label-free proteomics the secretome of p95HER2-induced senescent cells and compared the levels of the membrane-anchored proteins with their transcript levels. Then, protein and RNA levels of ADAM17 were evaluated by using Western blot and reverse transcription-polymerase chain reaction, its localization by using biotin labeling and immunofluorescence, and its activity by using alkaline phosphatase-tagged substrates. The p95HER2-expressing cell lines, senescent MCF7 and proliferating MCF10A, were analyzed to study ADAM17 regulation. Finally, we knocked down ADAM17 to determine its contribution to the senescence-associated secretome. The effect of this secretome was evaluated in migration assays in vitro and in nude mice by assessing the metastatic ability of orthotopically co-injected non-senescent cells.ResultsUsing breast cancer cells expressing p95HER2, a constitutively active fragment of the proto-oncogene HER2 that induces OIS, we show that the extracellular domains of a variety of membrane-bound proteins form part of the senescence secretome. We determine that these proteins are regulated transcriptionally and, in addition, that their shedding is limited by the protease ADAM17. The activity of the sheddase is constrained, at least in part, by the accumulation of cellular cholesterol. The blockade of ADAM17 abrogates several prometastatic effects of the p95HER2-induced senescence secretome, both in vitro and in vivo.ConclusionsConsidering these findings, we conclude that ectodomain shedding is tightly regulated in oncogene-induced senescent cells by integrating transcription of the shedding substrates with limiting ADAM17 activity. The remaining activity of ADAM17 contributes to the non-cell autonomous protumorigenic effects of p95HER2-induced senescent cells. Because ADAM17 is druggable, these results represent an approximation to the pharmacological regulation of the senescence secretome.Electronic supplementary materialThe online version of this article (doi:10.1186/s13058-015-0619-7) contains supplementary material, which is available to authorized users.

Abstract 2337: ADAM17 mediation of cancer stem cell-ness and chemo-resistance in colorectal cancer

Abstract INTRODUCTION: Despite the multitude of drug options, most patients with metastatic colorectal cancer (mCRC) die within 3 years of diagnosis. Response to systemic therapy is not durable (< 1year) and drug resistance is inevitable. There is accumulating evidence for the existence of cancer stem cells (CSCs) in CRC, which are now believed to mediate chemo-resistance. The molecular mechanisms that regulate the CSC phenotype in CRC have not been fully elucidated. The metalloproteinase ADAM17 [also known as TNFα-converting enzyme (TACE)], an enzyme involved in Notch pathway activation, has been shown to be overexpressed in CRC and mediate cell proliferation and chemo-resistance in CRC cells. However, the role of ADAM17 in mediating the CSC phenotype in CRC has not been characterized. The present study sought to determine the role of CRC-associated ADAM17 in mediating chemo-resistance of CRC cells by regulating the CSC phenotype. METHODS: Most preclinical studies used established cancer cell lines that have been cultured in vitro for decades. Our laboratory has shown that these cell lines are not suitable for consistent isolation of CSCs (Fan et al, 2014, BJC in press). To circumvent this problem, we developed a new model using CRC cells either freshly isolated from patient-derived xenografts (PDX) or early passage of newly established Human CRC Primary cell lines (HCP) derived from the PDXs. With this newly established HCP cell line model, we used siRNA knockdown or a synthetic peptide inhibitor TAPI-2, to determine the effect of blocking ADAM17 on the CSC phenotype and chemo-resistance in CRC cells. RESULTS: ADAM17 inhibition, either by siRNA or by TAPI-2, reduced the protein levels of cleaved Notch1 (NICD) and its downstream target HES-1 in CRC cells. Levels of proteins that are involved in other CSC-associated pathways were not altered by ADAM17 inhibition, suggesting that the Notch pathway is the major stem-cell pathway activated by ADAM17. Furthermore, ADAM17 inhibition caused a decrease in the CSC-phenotype in CRC cells as determined by the sphere formation assay and the Aldefluor assay (a standard assay for identifying CSCs). In addition, the lethal dose 50 (LD50) of 5-fluorouracil (5-FU) was decreased by 3 fold when pre-incubating CRC cells with the ADAM17 inhibitor TAPI-2. We also showed that the protein levels of ADAM17 were higher in our chemo-resistant cells (cells that survive continuous exposure to chemotherapy) compared to control. CONCLUSION: Our studies demonstrated the role of ADAM17 in promoting the CSC phenotype and chemo-resistance in CRC cells. Utilization of drugs that inhibit ADAM17 activity may increase the therapeutic benefit to patients with mCRC, and potentially other solid malignancies. Citation Format: Rui Wang, Fan Fan, Delphine Boulbes, Rajat Bhattacharya, Xiang-Cang Ye, Ling Xia, Lee Ellis. ADAM17 mediation of cancer stem cell-ness and chemo-resistance in colorectal cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2337. doi:10.1158/1538-7445.AM2015-2337

Abstract 4948: The cytosolic domain of a disintergrin and metalloprotease (ADAM) 15 promotes non-small cell lung cancer (NSCLC) proliferation

Abstract Emerging evidence has indicated that proteins of a disintergrin and metalloprotease (ADAM) family contribute to cancer progression and metastasis. One member of this family, ADAM15, was reported to over-express in multiple cancers, including gastric, lung, breast, and prostate cancers. It has been shown that the enzymatic activities of its extracellular metalloprotease domain mediate ErbB signaling pathway and promote breast cancer proliferation and migration. Nevertheless, in non-small cell lung cancer (NSCLC), the role of ADAM15 and its correlation to patient prognosis is still not well understood. Moreover, unlike in breast cancer, the enzymatic activities of the ADAM15 extracellular domain appeared to be independent of ErbB signaling and lung cancer proliferation, indicating an alternative mechanism of ADAM15 in promoting lung cancer progression. Here, we demonstrated that ADAM15 was over-expressed in primary NSCLC tissues compared to the adjacent normal tissues. Patients with ADAM15 high-expressing lung tumors had shorter survival times. Furthermore, we examined different isoforms of ADAM15 and discovered that, isoform 6 (i6), which contains the most cytoplasmic Src homology 3 (SH3) binding motifs, was significantly upregulated in primary lung cancer tissues. Comparison of i6 and isoform 1 (i1), which has no cytoplasmic SH3 binding motifs, revealed that the cytoplastmic domain is essential for lung cancer proliferation, as well as aggressiveness in an in vitro lung cancer migration model. We also showed that ADAM15 i6, but not i1, mediated ErbB signaling pathway through physical interaction with growth factor receptor-bound protein 2 (Grb2), and activation of Src homolog 2 domain containing (Shc). Most importantly, overexpression of ADAM15 i6 promoted NSCLC cell growth in a xenograft mouse model while knockdown of i6 resulted in tumor shrinkage. Thus, we identified a novel mechanism of the ADAM15 cytoplasmic domain in NSCLC tumor progression, which will not only shed light on the molecular mechanisms of ADAM proteins, but also facilitate development of novel therapy in NSCLC. Citation Format: Hsin-Han Hou. The cytosolic domain of a disintergrin and metalloprotease (ADAM) 15 promotes non-small cell lung cancer (NSCLC) proliferation. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 4948. doi:10.1158/1538-7445.AM2015-4948

Abstract A77: Investigating the role of ADAM10 in pancreatic tumor differentiation

Abstract Pancreatic adenocarcinoma (PDAC) is the 4th most common cause of cancer related deaths in the United States and has a dismal 5-year survival rate of 6%. This prognosis is attributed the disease’s fast and asymptomatic progression to metastasis, leading to late diagnosis upon which time there are few treatment options available. The A Disintegrin and Metalloproteinase (ADAM) family are sheddase proteins known to regulate cell adhesion and function. This regulation can allow ADAMs to influence the ability of tumor cells to disseminate from the primary tumor and metastasize to distant organs. ADAM10, which is seen to be up-regulated in both chronic pancreatitis and PDAC, cleaves a variety of substrates including several cell adhesion molecules such as L1-CAM, N-Cadherin, and E-Cadherin. Using a conditional knockout for ADAM10 in the Kras+/G12D;Ptf1a+/Cre (KC) mouse model of pancreatic cancer, we have observed an absence of metastasis when ADAM10 is genetically ablated. To investigate the potential role that ADAM10 plays in this, we used a shRNA approach to knock-down ADAM10 expression in various human pancreatic cancer cells lines. Analysis of these cell lines suggests a partial restoration of a less aggressive, differentiated phenotype, consistent with the increased longevity of the ADAM10 knockout KC mice. Citation Format: Louise V. Peverley, Christopher J. Halbrook, Jason C. Hall, Christine M. Ardito, Howard C. Crawford. Investigating the role of ADAM10 in pancreatic tumor differentiation. [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer: Innovations in Research and Treatment; May 18-21, 2014; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2015;75(13 Suppl):Abstract nr A77.

ADAM10: α-secretase in Alzheimer’s disease and regulator of neurobiology

Proteolytic and amyloidogenic processing of amyloid precursor protein (APP) by β- and γ-secretases are pathological hallmarks of Alzheimer’s disease (AD). These proteolytic activities lead to release of the amyloid-β peptides believed to cause neurological pathology and be linked to pathological progression in AD. Due to its capability to cleave APP within the toxic peptide sequence, the metalloproteinase ADAM10 (“a disintegrin and metalloprotease”) is a known antagonist of the disease-causing pathway. ADAM10 also plays a major role in the ectodomain shedding of a number of important cell surface proteins. In addition, ADAM10 is involved in the proteolytic activation cascade of the Notch receptor, which is of crucial function in developmental processes. The study of ADAM10-deficient mice also revealed that ADAM10 regulates synaptic function and synaptogenesis. Pharmacological activation of ADAM10 is postulated to represent a valuable strategy for prevention of AD. However, due to the multiple roles of ADAM10 in the brain, it will be challenging to find a suitable therapeutic window.

ADAM17 cleaves sphingosine 1 phosphate receptor 1 and regulates downstream signaling in endothelial cells (851.1)

Sphingosine‐1‐ phosphate receptor 1 (S1PR1) is a high affinity seven‐membrane G protein coupled receptor for bioactive lipid sphingosine‐1‐ phosphate (S1P). S1PR1 plays a critical role in regulating several endothelial cell functions such as proliferation, migration and importantly enhances endothelial barrier function. However, mechanism regulating S1PR1 cell surface retention remains unclear. Members of the ADAM (a disntintegrin and metalloproteases) family of proteases are known for cleaving the ectodomain of a variety of cell surface receptors thereby regulating their activities. In our present study, we addressed the possibility that ADAM family of proteases target S1PR1 and thereby downregulate it’s signaling in endothelial cells. We found that treatment of human pulmonary arterial endothelial (HPAE) cells with phorbol‐12‐myristate 13‐acetate (PMA), an activator of ADAM proteases, induces cleavage of S1PR1 within 2 hrs, while treatment with a broad range MMP inhibitor (TAPI‐0), stabilized S1PR1 expression. Additionally, PMA‐cleaved S1PR1 failed to localize on the cell surface rendering it refractive to exogenous S1P ligation and in enhancing the endothelial barrier. Also, Transendothelial resistance after ADAM17 deletion clearly shows enhanced barrier function. Over expression or depletion of ADAM17, but not ADAM10, in HPAE cells altered S1PR1 cell surface expression and endothelial barrier function by S1P identifying a novel role of ADAM17 as the protease responsible for targeting S1PR1.

Targeting CD13 (aminopeptidase-N) in turn downregulates ADAM17 by internalization in acute myeloid leukaemia cells.

Secreted matrix metalloproteinases (MMP)-2 and MMP-9 and membrane-anchored aminopeptidase-N/CD13 are abnormally expressed in human acute myeloid leukaemia (AML). We previously showed that CD13 ligation by anti-CD13 monoclonal antibodies can induce apoptosis in AML cells. Here, we assessed ADAM17 expression in primary blood blasts CD13+CD33+ from patients with AML. Primary AML cells expressed ADAM17 transcript and its surface expression was higher in subtype M4 (myelomonocytic) and M5 (monocytic) AML specimens than in M0 and M1/M2 (early and granulocytic) specimens. In AML cell lines defining distinct AML subfamilies (HL-60/M2, NB4/M3, THP-1/M5, U937/M5) and primary AML cells cultured ex vivo, anti-CD13 antibodies downregulated surface CD13 and ADAM17 without affecting MMP-2/-9 release. Knockdown of CD13 by siRNA prevented anti-CD13-mediated ADAM17 downregulation, indicating that CD13 is required for ADAM17 downregulation. Soluble ADAM17 was not detected in the medium of anti-CD13 treated cells, suggesting that ADAM17 was not shed. After ligation by anti-CD13, CD13 and ADAM17 were internalized. Subsequently, we found that ADAM17 interacts with CD13. We postulate that the interaction of ADAM17 with CD13 and its downregulation following CD13 engagement has important implications in AML for the known roles of ADAM17 in tumour-associated cell growth, migration and invasion.

86P The Role of Adam17 in Her2 Moderately Expressing Breast Cancer

ABSTRACT Trastuzumab has been shown to increase the survival of HER2 positive breast cancer (HER2 3+) patients and some clinical trials revealed that patients with moderately expressed HER2 (HER2 2+) breast cancer may also respond. However, there is a need to further understand the mechanisms of resistance to trastuzumab and to explore other targeted therapies. Members of a disintegrin and metalloproteases (ADAMs) are responsible for shedding of a variety of ErbB ligands. The most important members are ADAM10 and ADAM17 and we investigated the role of these ADAMs in trastuzumab treatment and resistance in HER2 2+ breast cancer cell lines. We first assessed the effect of trastuzumab on MDA-MB-453 and MDA-MB-361 cells and confirmed that those are less sensitive than HER2 positive SKBR3 cells but respond better than MCF7 cells. We found that trastuzumab treatment does not decrease pHER2 in HER2 2+ expressing cells. We previously showed that ADAM17 mediated heregulin release maintains HER2 phosphorylation in HER2 3+ breast cancer cells. Therefore we proceeded to investigate the levels of ADAM17 and heregulin and found an increase of both in HER2 2+ cells in comparison to SKBR3 cells. Interestingly, the use of a specific anti ADAM17 antibody leads to a decrease of pPKB as well as pHER3 and pHER2 in MDA-MB-453 cells. Strikingly, in cell viability studies monotherapy with an anti ADAM17 antibody had a significant effect in reducing cell proliferation of these cells and an additive effect in trastuzumab treatment. Furthermore, ADAM10 inhibition had only little effects, indicating that these cells may rely on HER3 activation through heregulin release by ADAM17. Thus, ADAM17 may play a key role in trastuzumab resistance in HER2 moderately expressing breast cancer cells. Our results suggest that in those cells, ADAM17 results in HER ligand sheddase which in turn may lead to the activation of HER receptors and the maintenance of pHER2. We demonstrated that an anti ADAM17 antibody is able to decrease pHER2, pHER3, as well as pPKB and is effective as monotherapy and additive to trastuzumab treatment in HER2 2+ breast cancer cells. We recommend that inhibition of ADAM17 with or without trastuzumab should be considered as a potential targeted therapy strategy in HER2 2+ breast cancer patients. Disclosure G. Murphy: The anti ADAM17 antibody was developed by Prof. Murphy's laboratory. Please see: Tape et al. Cross-domain inhibition of TACE ectodomain. Proc Natl Acad Sci USA 2011; 108(14):5578-83. All other authors have declared no conflicts of interest.