A Monoclonal Antibody to ADAM17 Inhibits Tumor Growth by Inhibiting EGFR and Non-EGFR-Mediated Pathways

Enhanced IL-15-mediated NK cell activation and proliferation by an ADAM17 function-blocking antibody involves CD16A, CD137, and accessory cells

BACKGROUND

Natural killer (NK) cells are being extensively studied as a cell therapy for cancer. These cells are activated by recognition of ligands and antigens on tumor cells. Cytokine therapies, such as IL-15, are also broadly used to stimulate endogenous and adoptively transferred NK cells in patients with cancer. These stimuli activate the membrane protease ADAM17, which cleaves various cell-surface receptors on NK cells as a negative feedback loop to limit their cytolytic function. ADAM17 inhibition can enhance IL-15-mediated NK cell proliferation in vitro and in vivo. In this study, we investigated the underlying mechanism of this process.

METHODS

Peripheral blood mononuclear cells (PBMCs) or enriched NK cells from human peripheral blood, either unlabeled or labeled with a cell proliferation dye, were cultured for up to 7 days in the presence of rhIL-15±an ADAM17 function-blocking antibody. Different fully human versions of the antibody were generated; Medi-1 (IgG1), Medi-4 (IgG4), Medi-PGLALA, Medi-F(ab')2, and TAB16 (anti-ADAM17 and anti-CD16 bispecific) to modulate CD16A binding. Flow cytometry was used to assess NK cell proliferation and phenotypic markers, immunoblotting to examine CD16A signaling, and IncuCyte-based live cell imaging to measure NK cell antitumor activity.

RESULTS

The ADAM17 function-blocking monoclonal antibody (mAb) Medi-1 markedly increased early NK cell activation by IL-15. By using different engineered versions of the antibody, we demonstrate involvement by CD16A, an activating Fcγ receptor and well-described ADAM17 substrate. Hence, Medi-1 when bound to ADAM17 on NK cells is engaged by CD16A and blocks its shedding, inducing and prolonging its signaling. This process did not promote evident NK cell fratricide or dysfunction. Synergistic signaling by Medi-1 and IL-15 enhanced the upregulation of CD137 on CD16A+ NK cells and augmented their proliferation in the presence of PBMC accessory cells or an anti-CD137 agonistic mAb.

CONCLUSIONS

Our data reveal for the first time that CD16A and CD137 underpin Medi-1 enhancement of IL-15-driven NK cell activation and proliferation, respectively, with the latter requiring PBMC accessory cells. The use of Medi-1 represents a novel strategy to enhance IL-15-driven NK cell proliferation, and it may be of therapeutic importance by increasing the antitumor activity of NK cells in patients with cancer.

Enhanced IL-15-mediated NK cell activation and proliferation by an ADAM17 function-blocking antibody involves CD16A, CD137, and accessory cells

Background

NK cells are being extensively studied as a cell therapy for cancer. Their effector functions are induced by the recognition of ligands on tumor cells and by various cytokines. IL-15 is broadly used to stimulate endogenous and adoptively transferred NK cells in cancer patients. These stimuli activate the membrane protease ADAM17, which then cleaves assorted receptors on the surface of NK cells as a negative feedback loop to limit their activation and function. We have shown that ADAM17 inhibition can enhance IL-15-mediated NK cell proliferation in vitro and in vivo . In this study, we investigated the underlying mechanism of this process.

Methods

PBMCs or enriched NK cells from human peripheral blood, either unlabeled or labeled with a cell proliferation dye, were cultured for up to 7 days in the presence of rhIL-15 +/- an ADAM17 function-blocking antibody. Different versions of the antibody were generated; Medi-1 (IgG1), Medi-4 (IgG4), Medi-PGLALA, Medi-F(ab') 2 , and TAB16 (anti-ADAM17 and anti-CD16 bispecific) to modulate CD16A engagement on NK cells. Flow cytometry was used to assess NK cell proliferation and phenotypic markers, immunoblotting to examine CD16A signaling, and IncuCyte-based live cell imaging to measure NK cell anti-tumor activity.

Results

The ADAM17 function-blocking mAb Medi-1 markedly increased initial NK cell activation by IL-15. Using different engineered versions of the antibody revealed that the activating Fcγ receptor CD16A, a well-described ADAM17 substrate, was critical for enhancing IL-15 stimulation. Hence, Medi-1 bound to ADAM17 on NK cells can be engaged by CD16A and block its shedding, inducing and prolonging its signaling. This process did not promote evident NK cell fratricide, phagocytosis, or dysfunction. Synergistic activity by Medi-1 and IL-15 enhanced the upregulation of CD137 on CD16A + NK cells and augmented their proliferation in the presence of PBMC accessory cells.

Conclusions

Our data reveal for the first time that CD16A and CD137 underpin Medi-1 enhancement of IL-15-driven NK cell activation and proliferation, respectively. The use of Medi-1 represents a novel strategy to enhance IL-15-driven NK cell proliferation, and it may be of therapeutic importance by increasing the anti-tumor activity of NK cells in cancer patients.

What is already known on this topic

NK cell therapies are being broadly investigated to treat cancer. NK cell stimulation by IL-15 prolongs their survival in cancer patients. Various stimuli including IL-15 activate ADAM17 in NK cells, a membrane protease that regulates the cell surface density of various receptors as a negative feedback mechanism.

What this study adds

Treating NK cells with the ADAM17 function-blocking mAb Medi-1 markedly enhanced their activation and proliferation. Our study reveals that the Fc and Fab regions of Medi-1 function synergistically with IL-15 in NK cell activation. Medi-1 treatment augments the upregulation of CD137 by NK cells, which enhances their proliferation in the presence of PBMC accessory cells.

How this study might affect research practice or policy

Our study is of translational importance as Medi-1 treatment in combination with IL-15 could potentially augment the proliferation and function of endogenous or adoptively transferred NK cells in cancer patients.

Graphical abstract

Soluble receptors in cancer: mechanisms, clinical significance, and therapeutic strategies

Soluble receptors are soluble forms of receptors found in the extracellular space. They have emerged as pivotal regulators of cellular signaling and disease pathogenesis. This review emphasizes their significance in cancer as diagnostic/prognostic markers and potential therapeutic targets. We provide an overview of the mechanisms by which soluble receptors are generated along with their functions. By exploring their involvement in cancer progression, metastasis, and immune evasion, we highlight the importance of soluble receptors, particularly soluble cytokine receptors and immune checkpoints, in the tumor microenvironment. Although current research has illustrated the emerging clinical relevance of soluble receptors, their therapeutic applications remain underexplored. As the landscape of cancer treatment evolves, understanding and targeting soluble receptors might pave the way for novel strategies for cancer diagnosis, prognosis, and therapy.

Fully human monoclonal antibody targeting activated ADAM10 on colorectal cancer cells

Metastasis and chemoresistance in colorectal cancer are mediated by certain poorly differentiated cancer cells, known as cancer stem cells, that are maintained by Notch downstream signaling initiated upon Notch cleavage by the metalloprotease ADAM10. It has been shown that ADAM10 overexpression correlates with aberrant signaling from Notch, erbBs, and other receptors, as well as a more aggressive metastatic phenotype, in a range of cancers including colon, gastric, prostate, breast, ovarian, uterine, and leukemia. ADAM10 inhibition, therefore, stands out as an important and new approach to deter the progression of advanced CRC. For targeting the ADAM10 substrate-binding region, which is located outside of the catalytic domain of the protease, we generated a human anti-ADAM10 monoclonal antibody named 1H5. Structural and functional characterization of 1H5 reveals that it binds to the substrate-binding cysteine-rich domain and recognizes an activated ADAM10 conformation present on tumor cells. The mAb inhibits Notch cleavage and proliferation of colon cancer cell lines in vitro and in mouse models. Consistent with its binding to activated ADAM10, the mAb augments the catalytic activity of ADAM10 towards small peptide substrates in vitro. Most importantly, in a mouse model of colon cancer, when administered in combination with the therapeutic agent Irinotecan, 1H5 causes highly effective tumor growth inhibition without any discernible toxicity effects. Our singular approach to target the ADAM10 substrate-binding region with therapeutic antibodies could overcome the shortcomings of previous intervention strategies of targeting the protease active site with small molecule inhibitors that exhibit musculoskeletal toxicity.

The role of EphA2 in ADAM17- and ionizing radiation-enhanced lung cancer cell migration

Purpose

Ionizing radiation (IR) enhances the migratory capacity of cancer cells. Here we investigate in non-small-cell-lung-cancer (NSCLC) cells a novel link between IR-enhanced ADAM17 activity and the non-canonical pathway of EphA2 in the cellular stress response to irradiation.

Methods

Cancer cell migration in dependence of IR, EphA2, and paracrine signaling mediated by ADAM17 was determined using transwell migration assays. Changes of EphA2 pS897 and mRNA expression levels upon different ADAM17-directed treatment strategies, including the small molecular inhibitor TMI-005, the monoclonal antibody MEDI3622, and shRNAs, were mechanistically investigated. ADAM17-mediated release and cleavage of the EphA2 ligand ephrin-A1 was measured using ELISA and an acellular cleavage assay.

Results

Irradiation with 5 Gy enhanced tumor cell migration of NSCLC NCI-H358 cells in dependence of EphA2. At the same time, IR increased growth factor-induced EphA2 S897 phosphorylation via auto- and paracrine signaling. Genetic and pharmaceutical downregulation of ADAM17 activity abrogated growth factor (e.g. amphiregulin) release, which reduced MAPK pathway-mediated EphA2 S897 phosphorylation in an auto- and paracrine way (non-canonical EphA2-pathway) in NCI-H358 and A549 cells. These signaling processes were associated with reduced cell migration towards conditioned media derived from ADAM17-deficient cells. Interestingly, ADAM17 inhibition with the small molecular inhibitor TMI-005 led to the internalization and proteasomal degradation of EphA2, which was rescued by amphiregulin or MG-132 treatment. In addition, ADAM17 inhibition also abrogated ephrin-A1 cleavage and thereby interfered with the canonical EphA2-pathway.

Conclusion

We identified ADAM17 and the receptor tyrosine kinase EphA2 as two important drivers for (IR-) induced NSCLC cell migration and described a unique interrelation between ADAM17 and EphA2. We demonstrated that ADAM17 influences both, EphA2 (pS897) and its GPI-anchored ligand ephrin-A1. Using different cellular and molecular readouts, we generated a comprehensive picture of how ADAM17 and IR influence the EphA2 canonical and non-canonical pathway in NSCLC cells.

A novel combination treatment of antiADAM17 antibody and erlotinib to overcome acquired drug resistance in non-small cell lung cancer through the FOXO3a/FOXM1 axis

After the identification of specific epidermal growth factor receptor (EGFR)-activating mutations as one of the most common oncogenic driver mutations in non-small cell lung cancer (NSCLC), several EGFR-tyrosine kinase inhibitors (EGFR-TKIs) with different clinical efficacies have been approved by various health authorities in the last two decades in targeting NSCLC harboring specific EGFR-activating mutations. However, most patients whose tumor initially responded to the first-generation EGFR-TKI developed acquired resistance. In this study, we developed a novel combination strategy, "antiADAM17 antibody A9(B8) + EGFR-TKIs", to enhance the efficacy of EGFR-TKIs. The addition of A9(B8) was shown to restore the effectiveness of erlotinib and overcome acquired resistance. We found that when A9(B8) antibody was treated with erlotinib or gefitinib, the combination treatment synergistically increased apoptosis in an NSCLC cell line and inhibited tumor growth in vivo. Interestingly, the addition of A9(B8) could only reduce the survival of the erlotinib-resistant NSCLC cell line and inhibit the growth of erlotinib-resistant tumors in vivo but not gefitinib-resistant cells. Furthermore, we revealed that A9(B8) overcame erlotinib resistance through the FOXO3a/FOXM1 axis and arrested the cell cycle at the G₁/S phase, resulting in the apoptosis of cancer cells. Hence, this study establishes a novel, promising strategy for overcoming acquired resistance to erlotinib through the FOXO3a/FOXM1 axis by arresting the cell cycle at the G₁/S phase.

Immunomodulatory role of metalloproteinase ADAM17 in tumor development

ADAM17 is a member of the a disintegrin and metalloproteinase (ADAM) family of transmembrane proteases involved in the shedding of some cell membrane proteins and regulating various signaling pathways. More than 90 substrates are regulated by ADAM17, some of which are closely relevant to tumor formation and development. Besides, ADAM17 is also responsible for immune regulation and its substrate-mediated signal transduction. Recently, ADAM17 has been considered as a major target for the treatment of tumors and yet its immunomodulatory roles and mechanisms remain unclear. In this paper, we summarized the recent understanding of structure and several regulatory roles of ADAM17. Importantly, we highlighted the immunomodulatory roles of ADAM17 in tumor development, as well as small molecule inhibitors and monoclonal antibodies targeting ADAM17.

ADAM10 and ADAM17 as Biomarkers Linked to Inflammation, Metabolic Disorders and Colorectal Cancer

ADAM10 and ADAM17 have a role in inflammation and diseases associated with inflammation, such as diabetes, cardiovascular diseases (CVD) or cancer, e.g., colorectal cancer (CRC). The aim of this study was to evaluate whether ADAM10 and ADAM17 could be biomarkers of CRC. To achieve this goal, CRC tumors and a surgical margin from 72 patients with CRC were collected. The concentration of ADAM proteins was measured by the ELISA method. Results were analyzed statistically and compared with selected clinical parameters. We found that ADAM17 protein concentration in the tumor samples was higher in patients with diabetes mellitus type 2 (DMT2) (0.28 vs. 0.2 ng/µg protein; p = 0.01) and in the surgical margin was higher both in patients with coexisting DMT2 (0.22 vs. 0.16 ng/µg protein; p < 0.05) and CVD (0.21 vs. 0.13 ng/µg protein; p < 0.01). The concentration of ADAM10 was higher in the surgical margin than in the tumor (249.34 vs. 228.82 pg/µg protein), and the concentration of ADAM17 was higher in the tumor than in the margin (0.23 vs. 0.18 ng/µg protein), but results were not statistically significant. In conclusion, the results of our study indicate that ADAM10 and ADAM17 may be potential biomarkers in cancer linked with DMT2 and CVD as diseases associated with inflammation.

An ADAM17-Neutralizing Antibody Reduces Inflammation and Mortality While Increasing Viral Burden in a COVID-19 Mouse Model

Angiotensin Converting Enzyme 2 (ACE2) is the primary cell entry receptor for SARS-CoV and SARS-CoV-2 viruses. A disintegrin and metalloproteinase 17 (ADAM17) is a protease that cleaves ectodomains of transmembrane proteins, including that of ACE2 and the proinflammatory cytokine TNF-α, from cell surfaces upon cellular activation. We hypothesized that blockade of ADAM17 activity would alter COVID-19 pathogenesis. To assess this pathway, we blocked the function of ADAM17 using the monoclonal antibody MEDI3622 in the K18-hACE2 transgenic mouse model of COVID-19. Antibody-treated mice were healthier, less moribund, and had significantly lower lung pathology than saline-treated mice. However, the viral burden in the lungs of MEDI3622-treated mice was significantly increased. Thus, ADAM17 appears to have a critical anti-viral role, but also may promote inflammatory damage. Since the inflammatory cascade is ultimately the reason for adverse outcomes in COVID-19 patients, there may be a therapeutic application for the MEDI3622 antibody.

Validating Cell Surface Proteases as Drug Targets for Cancer Therapy: What Do We Know, and Where Do We Go?

Cell surface proteases (also known as ectoproteases) are transmembrane and membrane-bound enzymes involved in various physiological and pathological processes. Several members, most notably dipeptidyl peptidase 4 (DPP4/CD26) and its related family member fibroblast activation protein (FAP), aminopeptidase N (APN/CD13), a disintegrin and metalloprotease 17 (ADAM17/TACE), and matrix metalloproteinases (MMPs) MMP2 and MMP9, are often overexpressed in cancers and have been associated with tumour dysfunction. With multifaceted actions, these ectoproteases have been validated as therapeutic targets for cancer. Numerous inhibitors have been developed to target these enzymes, attempting to control their enzymatic activity. Even though clinical trials with these compounds did not show the expected results in most cases, the field of ectoprotease inhibitors is growing. This review summarizes the current knowledge on this subject and highlights the recent development of more effective and selective drugs targeting ectoproteases among which small molecular weight inhibitors, peptide conjugates, prodrugs, or monoclonal antibodies (mAbs) and derivatives. These promising avenues have the potential to deliver novel therapeutic strategies in the treatment of cancers.

Immune Responses to IAV Infection and the Roles of L-Selectin and ADAM17 in Lymphocyte Homing

Influenza A virus (IAV) infection is a global public health burden causing up to 650,000 deaths per year. Yearly vaccination programmes and anti-viral drugs currently have limited benefits; therefore, research into IAV is fundamental. Leukocyte trafficking is a crucial process which orchestrates the immune response to infection to protect the host. It involves several homing molecules and receptors on both blood vessels and leukocytes. A key mediator of this process is the transmembrane glycoprotein L-selectin, which binds to vascular addressins on blood vessel endothelial cells. L-selectin classically mediates homing of naïve and central memory lymphocytes to lymph nodes via high endothelial venules (HEVs). Recent studies have found that L-selectin is essential for homing of activated CD8⁺ T cells to influenza-infected lungs and reduction in virus load. A disintegrin and metalloproteinase 17 (ADAM17) is the primary regulator of cell surface levels of L-selectin. Understanding the mechanisms that regulate these two proteins are central to comprehending recruitment of T cells to sites of IAV infection. This review summarises the immune response to IAV infection in humans and mice and discusses the roles of L-selectin and ADAM17 in T lymphocyte homing during IAV infection.

Inhibitory monoclonal antibody targeting ADAM17 expressed on cancer cells

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A novel anti-ADAM17 monoclonal antibody, D8P1C1, has been developed.

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D8P1C1 inhibits the proteolysis of peptide substrates by ADAM17.

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D8P1C1 inhibits the proliferation of cancer cells and tumor growth inhibition in vivo.

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D8P1C1 preferentially recognizes ADAM17 on cancer cells.

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Negative stain EM analysis reveals that D8P1C1 binds to the ADAM17 protease domain.

ADAM17 is upregulated in many cancers and in turn activates signaling pathways, including EGFR/ErbB, as well as those underlying resistance to targeted anti-EGFR therapies. Due to its central role in oncogenic pathways and drug resistance mechanisms, specific and efficacious monoclonal antibodies against ADAM17 could be useful for a broad patient population with solid tumors. Hence, we describe here an inhibitory anti-ADAM17 monoclonal antibody, named D8P1C1, that preferentially recognizes ADAM17 on cancer cells. D8P1C1 inhibits the catalytic activity of ADAM17 in a fluorescence-based peptide cleavage assay, as well as the proliferation of a range of cancer cell lines, including breast, ovarian, glioma, colon and the lung adenocarcinoma. In mouse models of triple-negative breast cancer and ovarian cancer, treatment with the mAb results in 78% and 45% tumor growth inhibition, respectively. Negative staining electron microscopy analysis of the ADAM17 ectodomain in complex with D8P1C1 reveals that the mAb binds the ADAM17 protease domain, consistent with its ability to inhibit the ADAM17 catalytic activity. Collectively, our results demonstrate the therapeutic potential of the D8P1C1 mAb to treat solid tumors.

Adamalizyny jako potencjalne biomarkery w wybranych nowotworach złośliwych przewodu pokarmowego

Nowotwory złośliwe przewodu pokarmowego zajmują czołowe miejsce zarówno wśród przyczyn zachorowań jak i zgonów z powodu chorób nowotworowych na świecie. Wciąż poszukuje się potencjalnych biomarkerów, które mogłyby posłużyć jako czynniki predykcyjne i prognostyczne w tych nowotworach. Wśród białek, które mogłyby pełnić taką rolę, wymienia się adamalizyny. Liczne białka z tej rodziny są zaangażowane w wielu etapach nowotworzenia, od procesu różnicowania się pojedynczych komórek, wzrost i progresję guza do tworzenia przerzutów odległych. Dzieje się to m.in. poprzez ścieżki sygnałowe związane z aktywacją insulinopodobnych czynników wzrostu, naskórkowych czynników wzrostu czy oddziaływanie na czynnik martwicy nowotworu TNF-α. Szczególnie istotna w wyjaśnieniu patomechanizmu rozwoju raków gruczołowych przewodu pokarmowego wydaje się ścieżka sygnałowa związana z aktywacją cytokin prozapalnych. Przewlekły stan zapalny jest bowiem dobrze udokumentowanym czynnikiem ryzyka rozwoju tej grupy chorób nowotworowych.

Poznanie roli białek z rodziny adamalizyn w rozwoju i patogenezie nowotworów złośliwych przewodu pokarmowego wymaga wciąż dalszych badań. W artykule podjęto próbę syntezy aktualnej wiedzy na temat wykorzystania wybranych białek z rodziny adamalizyn jako biomarkerów nowotworów złośliwych przewodu pokarmowego.

ADAM17 orchestrates Interleukin-6, TNFα and EGF-R signaling in inflammation and cancer

It was realized in the 1990s that some membrane proteins such as TNFα, both TNF receptors, ligands of the EGF-R and the Interleukin-6 receptor are proteolytically cleaved and are shed from the cell membrane as soluble proteins. The major responsible protease is a metalloprotease named ADAM17. So far, close to 100 substrates, including cytokines, cytokine receptors, chemokines and adhesion molecules of ADAM17 are known. Therefore, ADAM17 orchestrates many different signaling pathways and is a central signaling hub in inflammation and carcinogenesis. ADAM17 plays an important role in the biology of Interleukin-6 (IL-6) since the generation of the soluble Interleukin-6 receptor (sIL-6R) is needed for trans-signaling, which has been identified as the pro-inflammatory activity of this cytokine. In contrast, Interleukin-6 signaling via the membrane-bound Interleukin-6 receptor is mostly regenerative and protective. Probably due to its broad substrate spectrum, ADAM17 is essential for life and most of the few human individuals identified with ADAM17 gene defects died at young age. Although the potential of ADAM17 as a therapeutic target has been recognized, specific blockade of ADAM17 is not trivial since the metalloprotease domain of ADAM17 shares high structural homology with other proteases, in particular matrix metalloproteases. Here, the critical functions of ADAM17 in IL-6, TNFα and EGF-R pathways and strategies of therapeutic interventions are discussed.

Activation of ADAM17 by IL-15 Limits Human NK Cell Proliferation

Natural killer (NK) cells are innate cytotoxic lymphocytes that can recognize assorted determinants on tumor cells and rapidly kill these cells. Due to their anti-tumor effector functions and potential for allogeneic use, various NK cell platforms are being examined for adoptive cell therapies. However, their limited in vivo persistence is a current challenge. Cytokine-mediated activation of these cells is under extensive investigation and interleukin-15 (IL-15) is a particular focus since it drives their activation and proliferation. IL-15 efficacy though is limited in part by its induction of regulatory checkpoints. A disintegrin and metalloproteinase-17 (ADAM17) is broadly expressed by leukocytes, including NK cells, and it plays a central role in cleaving cell surface receptors, a process that regulates cell activation and cell-cell interactions. We report that ADAM17 blockade with a monoclonal antibody markedly increased human NK cell proliferation by IL-15 both in vitro and in a xenograft mouse model. Blocking ADAM17 resulted in a significant increase in surface levels of the homing receptor CD62L on proliferating NK cells. We show that NK cell proliferation in vivo by IL-15 and the augmentation of this process upon blocking ADAM17 are dependent on CD62L. Hence, our findings reveal for the first time that ADAM17 activation in NK cells by IL-15 limits their proliferation, presumably functioning as a feedback system, and that its substrate CD62L has a key role in this process in vivo. ADAM17 blockade in combination with IL-15 may provide a new approach to improve NK cell persistence and function in cancer patients.

Combined Radiochemotherapy: Metalloproteinases Revisited

Besides cytotoxic DNA damage irradiation of tumor cells triggers multiple intra- and intercellular signaling processes, that are part of a multilayered, treatment-induced stress response at the unicellular and tumor pathophysiological level. These processes are intertwined with intrinsic and acquired resistance mechanisms to the toxic effects of ionizing radiation and thereby co-determine the tumor response to radiotherapy. Proteolysis of structural elements and bioactive signaling moieties represents a major class of posttranslational modifications regulating intra- and intercellular communication. Plasma membrane-located and secreted metalloproteinases comprise a family of metal-, usually zinc-, dependent endopeptidases and sheddases with a broad variety of substrates including components of the extracellular matrix, cyto- and chemokines, growth and pro-angiogenic factors. Thereby, metalloproteinases play an important role in matrix remodeling and auto- and paracrine intercellular communication regulating tumor growth, angiogenesis, immune cell infiltration, tumor cell dissemination, and subsequently the response to cancer treatment. While metalloproteinases have long been identified as promising target structures for anti-cancer agents, previous pharmaceutical approaches mostly failed due to unwanted side effects related to the structural similarities among the multiple family members. Nevertheless, targeting of metalloproteinases still represents an interesting rationale alone and in combination with other treatment modalities. Here, we will give an overview on the role of metalloproteinases in the irradiated tumor microenvironment and discuss the therapeutic potential of using more specific metalloproteinase inhibitors in combination with radiotherapy.

Strategies to Target ADAM17 in Disease: From its Discovery to the iRhom Revolution

For decades, disintegrin and metalloproteinase 17 (ADAM17) has been the object of deep investigation. Since its discovery as the tumor necrosis factor convertase, it has been considered a major drug target, especially in the context of inflammatory diseases and cancer. Nevertheless, the development of drugs targeting ADAM17 has been harder than expected. This has generally been due to its multifunctionality, with over 80 different transmembrane proteins other than tumor necrosis factor α (TNF) being released by ADAM17, and its structural similarity to other metalloproteinases. This review provides an overview of the different roles of ADAM17 in disease and the effects of its ablation in a number of in vivo models of pathological conditions. Furthermore, here, we comprehensively encompass the approaches that have been developed to accomplish ADAM17 selective inhibition, from the newest non-zinc-binding ADAM17 synthetic inhibitors to the exploitation of iRhom2 to specifically target ADAM17 in immune cells.

Ectodomain shedding by ADAM17 (a disintegrin and metalloproteinase 17) in canine neutrophils

ADAM17 is a transmembrane protease expressed by most cells in humans and mice that cleaves cell surface substrates primarily in a cis manner, a process referred to as ectodomain shedding. ADAM17 has numerous substrates and plays a broad role in various physiological processes, including as a key regulator of inflammation. At this time, little is known about ADAM17 expression and function in dogs. A well-established ADAM17 substrate is the leukocyte adhesion protein CD62L (L-selectin). We show that a selective inhibitor of ADAM17, but not an inhibitor of its most closely related family member ADAM10, blocks CD62L shedding upon canine neutrophil activation. We also tested several anti-human ADAM17 monoclonal antibodies (mAbs) for staining canine neutrophils. Although most did not recognize canine neutrophils, the mAbs MEDI3622 and D1(A12) did. They also blocked the downregulation of CD62L upon neutrophil activation. MEDI3622 is a human IgG antibody and we found that a canine chimeric version of this mAb also blocked CD62L shedding by canine leukocytes. Taken together, our findings provide the first direct evidence of ADAM17 expression and sheddase activity in dogs, establishing a potential therapeutic target for various inflammatory disorders.

MAPK activity dynamics regulate non-cell autonomous effects of oncogene expression

A large fraction of human cancers contain genetic alterations within the Mitogen Activated Protein Kinase (MAPK) signaling network that promote unpredictable phenotypes. Previous studies have shown that the temporal patterns of MAPK activity (i.e. signaling dynamics) differentially regulate cell behavior. However, the role of signaling dynamics in mediating the effects of cancer driving mutations has not been systematically explored. Here, we show that oncogene expression leads to either pulsatile or sustained ERK activity that correlate with opposing cellular behaviors (i.e. proliferation vs. cell cycle arrest, respectively). Moreover, sustained-but not pulsatile-ERK activity triggers ERK activity waves in unperturbed neighboring cells that depend on the membrane metalloprotease ADAM17 and EGFR activity. Interestingly, the ADAM17-EGFR signaling axis coordinates neighboring cell migration toward oncogenic cells and is required for oncogenic cell extrusion. Overall, our data suggests that the temporal patterns of MAPK activity differentially regulate cell autonomous and non-cell autonomous effects of oncogene expression.

Blocking ADAM17 Function with a Monoclonal Antibody Improves Sepsis Survival in a Murine Model of Polymicrobial Sepsis

Sepsis is the culmination of hyperinflammation and immune suppression in response to severe infection. Neutrophils are critical early responders to bacterial infection but can become highly dysfunctional during sepsis and other inflammatory disorders. The transmembrane protease ADAM17 (a disintegrin and metalloproteinase 17) is expressed by leukocytes and most other cells and has many substrates that regulate inflammation. We have reported that conditional knockout mice lacking ADAM17 in all leukocytes had a survival advantage during sepsis, which was associated with improved neutrophil effector functions. These and other findings indicate aberrant ADAM17 activity during sepsis. For this study, we evaluated for the first time the effects of an ADAM17 function blocking monoclonal antibody (mAb) on the pathogenesis of polymicrobial sepsis. Mice treated with the ADAM17 mAb MEDI3622 prior to sepsis induction exhibited significantly decreased mortality. When the ADAM17 mAb was combined with antibiotic administration, sepsis survival was markedly enhanced compared to either intervention alone, which was associated with a significant reduction in plasma levels of various inflammation-related factors. MEDI3622 and antibiotic administration after sepsis induction also significantly improved survival. Our results indicate that the combination of blocking ADAM17 as an immune modulator and appropriate antibiotics may provide a new therapeutic avenue for sepsis treatment.

ADAM-Mediated Signalling Pathways in Gastrointestinal Cancer Formation

Tumour growth is not solely driven by tumour cell-intrinsic mechanisms, but also depends on paracrine signals provided by the tumour micro-environment. These signals comprise cytokines and growth factors that are synthesized as trans-membrane proteins and need to be liberated by limited proteolysis also termed ectodomain shedding. Members of the family of A disintegrin and metalloproteases (ADAM) are major mediators of ectodomain shedding and therefore initiators of paracrine signal transduction. In this review, we summarize the current knowledge on how ADAM proteases on tumour cells but also on cells of the tumour micro-environment contribute to the formation of gastrointestinal tumours, and discuss how these processes can be exploited pharmacologically.

ADAM17 selectively activates the IL-6 trans-signaling/ERK MAPK axis in KRAS-addicted lung cancer

Oncogenic KRAS mutations are major drivers of lung adenocarcinoma (LAC), yet the direct therapeutic targeting of KRAS has been problematic. Here, we reveal an obligate requirement by oncogenic KRAS for the ADAM17 protease in LAC In genetically engineered and xenograft (human cell line and patient-derived) Kras ^G12D-driven LAC models, the specific blockade of ADAM17, including with a non-toxic prodomain inhibitor, suppressed tumor burden by reducing cellular proliferation. The pro-tumorigenic activity of ADAM17 was dependent upon its threonine phosphorylation by p38 MAPK, along with the preferential shedding of the ADAM17 substrate, IL-6R, to release soluble IL-6R that drives IL-6 trans-signaling via the ERK1/2 MAPK pathway. The requirement for ADAM17 in Kras ^G12D-driven LAC was independent of bone marrow-derived immune cells. Furthermore, in KRAS mutant human LAC, there was a significant positive correlation between augmented phospho-ADAM17 levels, observed primarily in epithelial rather than immune cells, and activation of ERK and p38 MAPK pathways. Collectively, these findings identify ADAM17 as a druggable target for oncogenic KRAS-driven LAC and provide the rationale to employ ADAM17-based therapeutic strategies for targeting KRAS mutant cancers.

Recent developments and strategies for the discovery of TACE inhibitors

INTRODUCTION

TNF-α plays a central role in certain autoimmune diseases as well as in inflammation. The current strategy for excluding TNF-α from circulation is to selectively inhibit TNF-α converting enzyme (TACE), an enzyme that cleaves mTNF-α to active TNF-α. Various TACE inhibitors have been discovered by using different strategies to control inflammatory diseases, cancer, and cardiac hypertrophy.

AREAS COVERED

The present article summarizes the design and discovery of novel TACE inhibitors that have been reported in the literature since 2012 onwards. It also includes some reports concerning the new role that TACE plays in cancer and cardiac hypertrophy.

EXPERT OPINION

So far, undertaken studies that have looked to design and develop small TACE inhibitors have been discouraging due to the failure of any TACE inhibitors to hit the market. However, some of the latest developments, such as with tartrate-based inhibitors, has given hope to the potentiality of a viable novel selective TACE inhibitor therapeutic in the future. Indeed, some of the novel peptidomimetics and monoclonal antibodies have great potential to pave the way for an effective and safe therapy by selectively inhibiting TACE enzyme.

ADAM proteases: Emerging role and targeting of the non-catalytic domains

ADAM proteases are multi domain transmembrane metalloproteases that cleave a range of cell surface proteins and activate signaling pathways implicated in tumor progression, including those mediated by Notch, EFGR, and the Eph receptors. Consequently, they have emerged as key therapeutic targets in the efforts to inhibit tumor initiation and progression. To that end, two main approaches have been taken to develop ADAM antagonists: (i) small molecule inhibitors, and (ii) monoclonal antibodies. In this mini-review we describe the distinct features of ADAM proteases, particularly of ADAM10 and ADAM17, their domain organization, conformational rearrangements, regulation, as well as their emerging importance as therapeutic targets in cancer. Further, we highlight an anti-ADAM10 monoclonal antibody that we have recently developed, which has shown significant promise in inhibiting Notch signaling and deterring growth of solid tumors in pre-clinical settings.

Adamalysines as Biomarkers and a Potential Target of Therapy in Colorectal Cancer Patients: Preliminary Results

Colorectal cancer is one of the most common cancers in the world. Due to its still undetermined pathogenesis, we are searching for signaling pathways that are important in the development of colorectal cancer. In this article, we present results of study on the role of ADAM proteins in colorectal cancer. The study included 85 adult colorectal cancer patients (48 men, 37 women) and 25 patients in the control group (after diagnostic colonoscopy-without cancer). During hospitalization, a serum sample (3 cm³) was collected from the study and control group, anthropometric measurements were conducted and others clinical data were analyzed. In the serum ADAM10, 12, 17, and 28, protein concentrations were determined and, in the next step, examined the relationship between ADAMs concentrations and selected clinical parameters in both groups. The analysis showed that serum levels of ADAM10 and ADAM28 are significantly higher in patients with colorectal cancer and correlate with histopathological grading and with presence of distant metastases. Moreover, noticed the trend to correlate concentrations of adamalysines with higher BMI score. One of the functions of adamalysines is the activation of growth factors involved in cancer, including IGF and TNFα. The increased activity of adamalysines in patients may play a role in the pathogenesis of colorectal cancer. Our study highlights the prevalence of metabolic disorders in the group of patients with diagnosed CRC, and this cancer seems to be a further complication of obesity.

Inhibitory Antibodies Designed for Matrix Metalloproteinase Modulation

The family of matrix metalloproteinases (MMPs) consists of a set of biological targets that are involved in a multitude of severe pathogenic events such as different forms of cancers or arthritis. Modulation of the target class with small molecule drugs has not led to the anticipated success until present, as all clinical trials failed due to unacceptable side effects or a lack of therapeutic outcome. Monoclonal antibodies offer a tremendous therapeutic potential given their high target selectivity and good pharmacokinetic profiles. For the treatment of a variety of diseases there are already antibody therapies available and the number is increasing. Recently, several antibodies were developed for the selective inhibition of single MMPs that showed high potency and were therefore investigated in in vivo studies with promising results. In this review, we highlight the progress that has been achieved toward the design of inhibitory antibodies that successfully modulate MMP-9 and MMP-14.

Role of ADAM17 as a regulatory checkpoint of CD16A in NK cells and as a potential target for cancer immunotherapy

Human NK cell antitumor activities involve Ab-dependent cell-mediated cytotoxicity (ADCC), which is a key mechanism of action for several clinically successful tumor-targeting therapeutic mAbs. Human NK cells exclusively recognize these Abs by the Fcγ receptor CD16A (FcγRIIIA), one of their most potent activating receptors. Unlike other activating receptors on NK cells, CD16A undergoes a rapid down-regulation in expression by a proteolytic process following NK cell activation with various stimuli. In this review, the role of a disintegrin and metalloproteinase-17 (ADAM17) in CD16A cleavage and as a regulatory checkpoint is discussed. Several studies have examined the effects of inhibiting ADAM17 or CD16A cleavage directly during NK cell engagement of Ab-coated tumor cells, which resulted in strengthened Ab tethering, decreased tumor cell detachment, and enhanced CD16A signaling and cytokine production. However, the effects of either manipulation on ADCC have varied between studies, which may be due to dissimilar assays and the contribution of different killing processes by NK cells. Of importance is that NK cells under various circumstances, including in the tumor microenvironment of patients, down-regulate CD16A and this appears to impair their function. Considerable progress has been made in the development of ADAM17 inhibitors, including human mAbs that have advantages of high specificity and increased half-life in vivo. These inhibitors may provide a therapeutic means of increasing ADCC potency and/or antitumor cytokine production by NK cells in an immunosuppressive tumor microenvironment, and if used in combination with tumor-targeting Abs or NK cell-based adoptive immunotherapies may improve their efficacy.

Exome sequencing in 51 early onset non-familial CRC cases

Background

Colorectal cancer (CRC) cases with an age of onset <40 years suggests a germline genetic cause. In total, 51 simplex cases were included to test the hypothesis of CRC as a mendelian trait caused by either heterozygous autosomal dominant or bi‐allelic autosomal recessive pathogenic variants.

Methods

The cohort was whole exome sequenced (WES) at 100× coverage. Both a dominant‐ and recessive model were used for searching predisposing genetic factors. In addition, we assayed recessive variants of potential moderate risk that were enriched in our young‐onset CRC cohort. Variants were filtered using a candidate cancer gene list or by selecting variants more likely to be pathogenic based on variant type (e.g., loss‐of‐function) or allele frequency.

Results

We identified one pathogenic variant in PTEN in a patient subsequently confirmed to have a hereditary hamartoma tumor syndrome (Cowden syndrome) and one patient with a pathogenic heterozygous variant in PMS2 that was originally not identified by WES due to low quality reads resulting from pseudogenes. In addition, we identified three heterozygous candidate missense variants in known cancer susceptibility genes (BMPR1A,BRIP1, and SRC), three truncating variants in possibly novel cancer genes (CLSPN,SEC24B, SSH2) and four candidate missense variants in ACACA, NR2C2, INPP4A, and DIDO1. We also identify five possible autosomal recessive candidate genes: ATP10B,PKHD1,UGGT2,MYH13,TFF3.

Conclusion

Two clear pathogenic variants were identified in patients that had not been identified clinically. Thus, the chance of detecting a hereditary cancer syndrome in patients with CRC at young age but without family history is 2/51 (4%) and therefore the clinical benefit of genetic testing in this patient group is low. Of note, using stringent filtering, we have identified a total of ten candidate heterozygous variants and five possibly biallelic autosomal recessive candidate genes that warrant further study.

[ADAM17 knockdown increases sensitivity of SW480 cells to cetuximad]

OBJECTIVE

To explore the association between expression of ADAM17 and cetuximad resistance in human colorectal cancer SW480 cells.

METHODS

The expression of ADAM17 was detected using Western blotting in different human colorectal cancer cell lines, and the cells highly expressing ADAM17 were selected as the target cells. SW480 cells were transfected with ADAM17-siRNA 1 and ADAM17-siRNA 2 and the changes in the expression of ADAM17 protein were detected using Western blotting. SW480 cells were exposed to cetuximad for 24 h and the cell apoptosis was analyzed using flow cytometry. Transwell assay was used to examine the migration ability of SW480 cells with different expression levels of ADAM17; Western blotting was used to analyze the changes in the expressions of AKT signaling pathway-related proteins in the treated cells.

RESULTS

The baseline expressions of ADAM17 were significantly higher in SW480 cells than in the other human colorectal cancer cell lines tested (P &lt; 0.05). Both ADAM17-siRNA 1 and 2 effectively reduced the expression of ADAM17 protein in SW480 cells. Knockdown of ADAM17 with siRNA 1 significantly increased the sensitivity of SW480 cells to tocetuximad (P &lt; 0.05), obviously inhibited the cell proliferation, migration and invasion, and significantly reduced the expressions of p-EGFR and p-AKT in the cells (P &lt; 0.001).

CONCLUSIONS

ADAM17 knockdown obviously inhibits EGFR-AKT signaling pathway and increases the sensitivity of SW480 cells to tocetuximad.

Renal ADAM10 and 17: Their Physiological and Medical Meanings

A disintegrin and metalloproteinases (ADAMs) are a Zn²⁺-dependent transmembrane and secreted metalloprotease superfamily, so-called “molecular scissors,” and they consist of an N-terminal signal sequence, a prodomain, zinc-binding metalloprotease domain, disintegrin domain, cysteine-rich domain, transmembrane domain and cytoplasmic tail. ADAMs perform proteolytic processing of the ectodomains of diverse transmembrane molecules into bioactive mediators. This review summarizes on their most well-known members, ADAM10 and 17, focusing on the kidneys. ADAM10 is expressed in renal tubular cells and affects the expression of specific brush border genes, and its activation is involved in some renal diseases. ADAM17 is weakly expressed in normal kidneys, but its expression is markedly induced in the tubules, capillaries, glomeruli, and mesangium, and it is involved in interstitial fibrosis and tubular atrophy. So far, the various substrates have been identified in the kidneys. Shedding fragments become released ligands, such as Notch and EGFR ligands, and act as the chemoattractant factors including CXCL16. Their ectodomain shedding is closely correlated with pathological factors, which include inflammation, interstitial fibrosis, and renal injury. Also, the substrates of both ADAMs contain the molecules that play important roles at the plasma membrane, such as meaprin, E-cadherin, Klotho, and CADM1. By being released into urine, the shedding products could be useful for biomarkers of renal diseases, but ADAM10 and 17 per se are also notable as biomarkers. Furthermore, ADAM10 and/or 17 inhibitions based on various strategies such as small molecules, antibodies, and their recombinant prodomains are valuable, because they potentially protect renal tissues and promote renal regeneration. Although temporal and spatial regulations of inhibitors are problems to be solved, their inhibitors could be useful for renal diseases.

Anti-ADAM17 monoclonal antibody MEDI3622 increases IFNγ production by human NK cells in the presence of antibody-bound tumor cells

Several clinically successful tumor-targeting mAbs induce NK cell effector functions. Human NK cells exclusively recognize tumor-bound IgG by the FcR CD16A (FcγRIIIA). Unlike other NK cell activating receptors, the cell surface density of CD16A can be rapidly downregulated in a cis manner by the metalloproteinase ADAM17 following NK cell stimulation in various manners. CD16A downregulation takes place in cancer patients and this may affect the efficacy of tumor-targeting mAbs. We examined the effects of MEDI3622, a human mAb and potent ADAM17 inhibitor, on NK cell activation by antibody-bound tumor cells. MEDI3622 effectively blocked ADAM17 function in NK cells and caused a marked increase in their production of IFNγ. This was observed for NK cells exposed to different tumor cell lines and therapeutic antibodies, and over a range of effector/target ratios. The augmented release of IFNγ by NK cells was reversed by a function-blocking CD16A mAb. In addition, NK92 cells, a human NK cell line that lacks endogenous FcγRs, expressing a recombinant non-cleavable version of CD16A released significantly higher levels of IFNγ than NK92 cells expressing equivalent levels of wildtype CD16A. Taken together, our data show that MEDI3622 enhances the release of IFNγ by NK cells engaging antibody-bound tumor cells by blocking the shedding of CD16A. These findings support ADAM17 as a dynamic inhibitory checkpoint of the potent activating receptor CD16A, which can be targeted by MEDI3622 to potentially increase the efficacy of anti-tumor therapeutic antibodies.

Monoclonal antibodies against metzincin targets

The metzincin clan of metalloproteinases includes the MMP, disintegrin and metalloproteinase (ADAM) and ADAM with thrombospondin motifs families, which cleave extracellular targets in a wide range of (patho)physiological processes. Antibodies constitute a powerful tool to modulate the activity of these enzymes for both therapeutic and research purposes. In this review, we give an overview of monoclonal antibodies (mAbs) that have been tested in preclinical disease models, human trials and important studies of metzincin structure and function. Initial attempts to develop therapeutic small molecule inhibitors against MMPs were hampered by structural similarities between metzincin active sites and, consequently, off-target effects. Therefore, more recently, mAbs have been developed that do not bind to the active site but bind to surface-exposed loops that are poorly conserved in closely related family members. Inhibition of protease activity by these mAbs occurs through a variety of mechanisms, including (i) barring access to the active site, (ii) disruption of exosite binding, and (iii) prevention of protease activation. These different modes of inhibition are discussed in the context of the antibodies' potency, selectivity and, importantly, the effects in models of disease and clinical trials. In addition, various innovative strategies that were used to generate anti-metzincin mAbs are discussed. LINKED ARTICLES: This article is part of a themed section on Translating the Matrix. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v176.1/issuetoc.

Recent Advances in ADAM17 Research: A Promising Target for Cancer and Inflammation

Since its discovery, ADAM17, also known as TNFα converting enzyme or TACE, is now known to process over 80 different substrates. Many of these substrates are mediators of cancer and inflammation. The field of ADAM metalloproteinases is at a crossroad with many of the new potential therapeutic agents for ADAM17 advancing into the clinic. Researchers have now developed potential drugs for ADAM17 that are selective and do not have the side effects which were seen in earlier chemical entities that targeted this enzyme. ADAM17 inhibitors have broad therapeutic potential, with properties ranging from tumor immunosurveillance and overcoming drug and radiation resistance in cancer, as treatments for cardiac hypertrophy and inflammatory conditions such as inflammatory bowel disease and rheumatoid arthritis. This review focuses on substrates and inhibitors identified more recently for ADAM17 and their role in cancer and inflammation.

Clinical Implications of Compounds Designed to Inhibit ECM-Modifying Metalloproteinases

Remodeling of the extracellular matrix (ECM) is crucial in development and homeostasis, but also has a significant role in disease progression. Two metalloproteinase families, the matrix metalloproteinases (MMPs) and a disintegrin and metalloproteases (ADAMs), participate in the remodeling of the ECM, either directly or through the liberation of growth factors and cell surface receptors. The correlation of MMP and ADAM activity to a variety of diseases has instigated numerous drug development programs. However, broad-based and Zn²⁺ -chelating MMP and ADAM inhibitors have fared poorly in the clinic. Selective MMP and ADAM inhibitors have been described recently based on (a) antibodies or antibody fragments or (b) small molecules designed to take advantage of protease secondary binding sites (exosites) or allosteric sites. Clinical trials have been undertaken with several of these inhibitors, while others are in advanced pre-clinical stages.

Targeting ADAM17 inhibits human colorectal adenocarcinoma progression and tumor-initiating cell frequency

ADAM17 (a disintegrin and metalloproteinase 17)/TACE (TNFα converting enzyme) has emerged as a potential therapeutic target in colorectal cancer (CRC) and other cancers, due in part to its role in regulating various tumor cell surface proteins and growth factors and cytokines in the tumor microenvironment. The emergence of MEDI3622, a highly potent and specific antibody-based ADAM17 inhibitor, has allowed testing of the concept that targeting ADAM17 may be an important new therapeutic approach for CRC patients. We demonstrate that MEDI3622 is highly efficacious on tumor growth in multiple human CRC PDX models, resulting in improved survival of animals bearing tumor xenografts. MEDI3622 was further found to impact Notch pathway activity and tumor-initiating cells. The promising preclinical activity seen here supports further clinical investigation of this treatment approach to improve therapeutic outcome for patients diagnosed with metastatic CRC, including patients with KRAS-mutant tumors for whom other therapeutic options are currently limited.

Molecular Pathways: Receptor Ectodomain Shedding in Treatment, Resistance, and Monitoring of Cancer

Proteases known as sheddases cleave the extracellular domains of their substrates from the cell surface. The A Disintegrin and Metalloproteinases ADAM10 and ADAM17 are among the most prominent sheddases, being widely expressed in many tissues, frequently overexpressed in cancer, and promiscuously cleaving diverse substrates. It is increasingly clear that the proteolytic shedding of transmembrane receptors impacts pathophysiology and drug response. Receptor substrates of sheddases include the cytokine receptors TNFR1 and IL6R; the Notch receptors; type-I and -III TGFβ receptors; receptor tyrosine kinases (RTK) such as HER2, HER4, and VEGFR2; and, in particular, MET and TAM-family RTKs AXL and Mer (MerTK). Activation of receptor shedding by mechanical cues, hypoxia, radiation, and phosphosignaling offers insight into mechanisms of drug resistance. This particularly holds for kinase inhibitors targeting BRAF (such as vemurafenib and dabrafenib) and MEK (such as trametinib and cobimetinib), along with direct sheddase inhibitors. Receptor proteolysis can be detected in patient fluids and is especially relevant in melanoma, glioblastoma, lung cancer, and triple-negative breast cancer where RTK substrates, MAPK signaling, and ADAMs are frequently dysregulated. Translatable strategies to exploit receptor shedding include combination kinase inhibitor regimens, recombinant decoy receptors based on endogenous counterparts, and, potentially, immunotherapy. Clin Cancer Res; 23(3); 623-9. ©2016 AACR.

Current status of proteomics of esophageal carcinoma

INTRODUCTION

Esophageal cancer (EC) is one of the most common causes of cancer-related death worldwide. Identifying suitable biomarkers for early diagnosis as well as predicting lymph node metastasis, prognosis and the therapeutic response of EC is essential for the effective and efficient management for EC. There is an urgent need to develop effective, novel approaches for patients who do not respond to conventional treatment. Areas covered: EC is characterized by the presence of two main histological types such as squamous cell carcinoma and adenocarcinoma, which differ in their response to treatments and prognosis. Thus, this review describes the latest research into biomarkers and novel treatment targets generated by cancer proteomics for the two main histological types. Finally, the main difficulties facing the translation of biomarkers and novel treatment targets into the clinical settings are discussed. Expert commentary: EC proteomics have provided useful results and, after their validation, novel clinical tools should be developed to improve the clinical outcomes for EC patients.

Molecular basis for the mechanism of action of an anti-TACE antibody

Inhibitors of tumor necrosis factor-α converting enzyme (TACE) have potential as therapeutics for various diseases. Many small molecule inhibitors, however, exhibit poor specificity profiles because they target the highly conserved catalytic cleft of TACE. We report for the first time the molecular interaction of a highly specific anti-TACE antagonistic antibody (MEDI3622). We characterized the binding of MEDI3622 using mutagenesis, as well as structural modeling and docking approaches. We show that MEDI3622 recognizes a unique surface loop of sIVa-sIVb β-hairpin on TACE M-domain, but does not interact with the conserved catalytic cleft or its nearby regions. The exquisite specificity of MEDI3622 is mediated by this distinct structural feature on the TACE M-domain. These findings may aid the design of antibody therapies against TACE.

ADAM17 is a Tumor Promoter and Therapeutic Target in Western Diet-associated Colon Cancer

PURPOSE

Epidermal growth factor receptors (EGFR) are required for tumor promotion by Western diet. The metalloprotease, ADAM17 activates EGFR by releasing pro-EGFR ligands. ADAM17 is regulated by G-protein-coupled receptors, including CXCR4. Here we investigated CXCR4-ADAM17 crosstalk and examined the role of ADAM17 in tumorigenesis.

EXPERIMENTAL DESIGN

We used CXCR4 inhibitor, AMD3100 and ADAM17 inhibitor, BMS566394 to assess CXCR4-ADAM17 crosstalk in colon cancer cells. We compared the expression of CXCR4 ligand, CXCL2, and ADAM17 in mice fed Western diet versus standard diet. Separately, mice were treated with marimastat, a broad-spectrum ADAM17 inhibitor, or AMD3100 to assess EGFR activation by ADAM17 and CXCR4. Using Apc-mutant Min mice, we investigated the effects of ADAM17/10 inhibitor INCB3619 on tumorigenesis. To assess the effects of colonocyte ADAM17, mice with ADAM17 conditional deletion were treated with azoxymethane (AOM). ADAM17 expression was also compared in colonocytes from primary human colon cancers and adjacent mucosa.

RESULTS

CXCL12 treatment activated colon cancer cell EGFR signals, and CXCR4 or ADAM17 blockade reduced this activation. In vivo, Western diet increased CXCL12 in stromal cells and TGFα in colonocytes. Marimastat or AMD3100 caused >50% reduction in EGFR signals (P < 0.05). In Min mice, INCB3619 reduced EGFR signals in adenomas and inhibited intestinal tumor multiplicity (P < 0.05). In the AOM model, colonocyte ADAM17 deletion reduced EGFR signals and colonic tumor development (P < 0.05). Finally, ADAM17 was upregulated >2.5-fold in human malignant colonocytes.

CONCLUSIONS

ADAM17 is a Western diet-inducible enzyme activated by CXCL12-CXCR4 signaling, suggesting the pathway: Western diet→CXCL12→CXCR4→ADAM17→TGFα→EGFR. ADAM17 might serve as a druggable target in chemoprevention strategies. Clin Cancer Res; 23(2); 549-61. ©2016 AACR.

The ADAMs family of proteases as targets for the treatment of cancer

The ADAMs (a disintegrin and metalloproteases) are transmembrane multidomain proteins implicated in multiple biological processes including proteolysis, cell adhesion, cell fusion, cell proliferation and cell migration. Of these varied activities, the best studied is their role in proteolysis. However, of the 22 ADAMs believed to be functional in humans, only approximately a half possess matrix metalloproteinase (MMP)-like protease activity. In contrast to MMPs which are mostly implicated in the degradation of extracellular matrix proteins, the main ADAM substrates are the ectodomains of type I and type II transmembrane proteins. These include growth factor/cytokine precursors, growth factor/cytokine receptors and adhesion proteins. Recently, several different ADAMs, especially ADAM17, have been shown to play a role in the development and progression of multiple cancer types. Consistent with this role in cancer, targeting ADAM17 with either low molecular weight inhibitors or monoclonal antibodies was shown to have anti-cancer activity in multiple preclinical systems. Although early phase clinical trials have shown no serious side effects with a dual ADAM10/17 low molecular weight inhibitor, the consequences of long-term treatment with these agents is unknown. Furthermore, efficacy in clinical trials remains to be shown.

Secretome Signature Identifies ADAM17 as Novel Target for Radiosensitization of Non-Small Cell Lung Cancer

PURPOSE

Ionizing radiation (IR) induces intracellular signaling processes as part of a treatment-induced stress response. Here we investigate IR-induced ADAM17 activation and the role of ADAM17-shed factors for radiation resistance in non-small cell lung cancer.

EXPERIMENTAL DESIGN

Large-scale secretome profiling was performed using antibody arrays. Secretion kinetics of ADAM17 substrates was determined using ELISA across multiple in vitro and in vivo models of non-small cell lung cancer. Clonogenic survival and tumor xenograft assays were performed to determine radiosensitization by ADAM17 inhibition.

RESULTS

On the basis of a large-scale secretome screening, we investigated secretion of auto- or paracrine factors in non-small cell lung cancer in response to irradiation and discovered the ADAM17 network as a crucial mediator of resistance to IR. Irradiation induced a dose-dependent increase of furin-mediated cleavage of the ADAM17 proform to active ADAM17, which resulted in enhanced ADAM17 activity in vitro and in vivo Genetic or pharmacologic targeting of ADAM17 suppressed IR-induced shedding of secreted factors, downregulated ErbB signaling in otherwise cetuximab-resistant target cells, and enhanced IR-induced cytotoxicity. The combined treatment modality of IR with the ADAM17 inhibitor TMI-005 resulted in a supra-additive antitumor response in vivo demonstrating the potential of ADAM17 targeting in combination with radiotherapy.

CONCLUSIONS

Radiotherapy activates ADAM17 in non-small cell lung cancer, which results in shedding of multiple survival factors, growth factor pathway activation, and IR-induced treatment resistance. We provide a sound rationale for repositioning ADAM17 inhibitors as short-term adjuvants to improve the radiotherapy outcome of non-small cell lung cancer. Clin Cancer Res; 22(17); 4428-39. ©2016 AACR.

A Disintegrin and Metalloproteinase Domain 17 Regulates Colorectal Cancer Stem Cells and Chemosensitivity Via Notch1 Signaling

The objective was to determine whether A disintegrin and metalloproteinase domain 17 (ADAM17) regulates the cancer stem cell (CSC) phenotype in colorectal cancer (CRC) and elucidate the downstream signaling mechanism mediating cancer stem-ness. The results showed that ADAM17 has a role in regulating the CSC phenotype and chemoresistance in CRC cells. Drugs that inhibit ADAM17 activity might increase the therapeutic benefit to metastatic CRC and, potentially, other solid malignancies.

Evidence is accumulating for the role of cancer stem cells (CSCs) in mediating chemoresistance in patients with metastatic colorectal cancer (mCRC). A disintegrin and metalloproteinase domain 17 (ADAM17; also known as tumor necrosis factor-α-converting enzyme [TACE]) was shown to be overexpressed and to mediate cell proliferation and chemoresistance in CRC cells. However, its role in mediating the CSC phenotype in CRC has not been well-characterized. The objective of the present study was to determine whether ADAM17 regulates the CSC phenotype in CRC and to elucidate the downstream signaling mechanism that mediates cancer stemness. We treated established CRC cell lines and a newly established human CRC cell line HCP-1 with ADAM17-specific small interfering RNA (siRNA) or the synthetic peptide inhibitor TAPI-2. The effects of ADAM17 inhibition on the CSC phenotype and chemosensitivity to 5-fluorouracil (5-FU) in CRC cells were examined. siRNA knockdown and TAPI-2 decreased the protein levels of cleaved Notch1 (Notch1 intracellular domain) and HES-1 in CRC cells. A decrease in the CSC phenotype was determined by sphere formation and ALDEFLUOR assays. Moreover, TAPI-2 sensitized CRC cells to 5-FU by decreasing cell viability and the median lethal dose of 5-FU and increasing apoptosis. We also showed the cleavage and release of soluble Jagged-1 and -2 by ADAM17 in CRC cells. Our studies have elucidated a role of ADAM17 in regulating the CSC phenotype and chemoresistance in CRC cells. The use of drugs that inhibit ADAM17 activity might increase the therapeutic benefit to patients with mCRC and, potentially, those with other solid malignancies.

Significance

The present study has demonstrated the role of A disintegrin and metalloproteinase domain 17 (ADAM17) in regulating cancer stemness and chemosensitivity in colorectal cancer (CRC) cells. In addition, a previously unknown cleavage of the Notch ligands Jagged-1 and -2 by ADAM17 in CRC cells is reported. These findings will have an impact on future studies of the regulation of cancer stem cells in CRC and, potentially, other cancer types.

Targeting autocrine HB-EGF signaling with specific ADAM12 inhibition using recombinant ADAM12 prodomain

Dysregulation of ErbB-family signaling underlies numerous pathologies and has been therapeutically targeted through inhibiting ErbB-receptors themselves or their cognate ligands. For the latter, “decoy” antibodies have been developed to sequester ligands including heparin-binding epidermal growth factor (HB-EGF); however, demonstrating sufficient efficacy has been difficult. Here, we hypothesized that this strategy depends on properties such as ligand-receptor binding affinity, which varies widely across the known ErbB-family ligands. Guided by computational modeling, we found that high-affinity ligands such as HB-EGF are more difficult to target with decoy antibodies compared to low-affinity ligands such as amphiregulin (AREG). To address this issue, we developed an alternative method for inhibiting HB-EGF activity by targeting its cleavage from the cell surface. In a model of the invasive disease endometriosis, we identified A Disintegrin and Metalloproteinase 12 (ADAM12) as a protease implicated in HB-EGF shedding. We designed a specific inhibitor of ADAM12 based on its recombinant prodomain (PA12), which selectively inhibits ADAM12 but not ADAM10 or ADAM17. In endometriotic cells, PA12 significantly reduced HB-EGF shedding and resultant cellular migration. Overall, specific inhibition of ligand shedding represents a possible alternative to decoy antibodies, especially for ligands such as HB-EGF that exhibit high binding affinity and localized signaling.