Modulation of Macropinocytosis-Mediated Internalization Decreases Ocular Toxicity of Antibody-Drug Conjugates.

AGS-16C3F is an antibody-drug conjugate (ADC) against ectonucleotide pyrophosphatase/phosphodiesterase 3 (ENPP3) containing the mcMMAF linker-payload currently in development for treatment of metastatic renal cell carcinoma. AGS-16C3F and other ADCs have been reported to cause ocular toxicity in patients by unknown mechanisms. To investigate this toxicity, we developed an assay using human corneal epithelial cells (HCEC) and show that HCECs internalized AGS-16C3F and other ADCs by macropinocytosis, causing inhibition of cell proliferation.

A Potential Mechanism for ADC-Induced Neutropenia: Role of Neutrophils in Their Own Demise.

Neutropenia is a common adverse event in cancer patients treated with antibody-drug conjugates (ADC) and we aimed to elucidate the potential mechanism of this toxicity. To investigate whether ADCs affect neutrophil production from bone marrow, an assay was developed in which hematopoietic stem cells (HSC) were differentiated to neutrophils. Several antibodies against targets absent in HSCs and neutrophils were conjugated to MMAE via a cleavable valine-citrulline linker (vcMMAE-ADC) or MMAF via a noncleavable maleimidocaproyl linker (mcMMAF-ADC), and their cytotoxicity was tested in the neutrophil differentiation assay.

The Discovery and Preclinical Development of ASG-5ME, an Antibody-Drug Conjugate Targeting SLC44A4-Positive Epithelial Tumors Including Pancreatic and Prostate Cancer.

Here, we report the development of an antibody-drug conjugate, ASG-5ME, which targets the solute carrier receptor SLC44A4. SLC44A4 is a member of a family of putative choline transporters that we show to be markedly upregulated in a variety of epithelial tumors, most notably prostate and pancreatic cancer. SLC44A4 is normally expressed on the apical surface of secretory epithelial cells, but in cancer we show expression is not restricted to the luminal surface in advanced and undifferentiated tumors.

Preclinical Evaluation of an Anti-Nectin-4 ImmunoPET Reagent in Tumor-Bearing Mice and Biodistribution Studies in Cynomolgus Monkeys.

Purpose: Nectin-4 is selectively overexpressed in a variety of cancers and is currently under clinical investigation as a therapeutic target. A monoclonal antibody against nectin-4 (AGS-22M6) was evaluated as an Immuno-positron emission tomography (ImmunoPET) reagent. Its ability to assay nectin-4 expression as well as detect nectin-4 positive tumors in the liver and bone was evaluated using mouse models.

Enfortumab Vedotin Antibody-Drug Conjugate Targeting Nectin-4 Is a Highly Potent Therapeutic Agent in Multiple Preclinical Cancer Models.

The identification of optimal target antigens on tumor cells is central to the advancement of new antibody-based cancer therapies. We performed suppression subtractive hybridization and identified nectin-4 (PVRL4), a type I transmembrane protein and member of a family of related immunoglobulin-like adhesion molecules, as a potential target in epithelial cancers. We conducted immunohistochemical analysis of 2,394 patient specimens from bladder, breast, lung, pancreatic, ovarian, head/neck, and esophageal tumors and found that 69% of all specimens stained positive for nectin-4.

Development of ASG-15ME, a Novel Antibody-Drug Conjugate Targeting SLITRK6, a New Urothelial Cancer Biomarker.

SLITRK6 is a member of the SLITRK family of neuronal transmembrane proteins that was discovered as a bladder tumor antigen using suppressive subtractive hybridization. Extensive immunohistochemistry showed SLITRK6 to be expressed in multiple epithelial tumors, including bladder, lung, and breast cancer as well as in glioblastoma. To explore the possibility of using SLITRK6 as a target for an antibody-drug conjugate (ADC), we generated a panel of fully human mAbs specific for SLITRK6.

AGS16F Is a Novel Antibody Drug Conjugate Directed against ENPP3 for the Treatment of Renal Cell Carcinoma.

Purpose: New cancer-specific antigens are required for the design of novel antibody-drug conjugates (ADC) that deliver tumor-specific and highly potent cytotoxic therapy.

Experimental Design: Suppression subtractive hybridization identified ectonucleotide pyrophosphatase/phosphodiesterase 3 (ENPP3 or CD203c) as a potential human cancer-specific antigen. Antibodies targeting the extracellular domain of human ENPP3 were produced and selected for specific binding to ENPP3.

AGS67E, an Anti-CD37 Monomethyl Auristatin E Antibody-Drug Conjugate as a Potential Therapeutic for B/T-Cell Malignancies and AML: A New Role for CD37 in AML.

CD37 is a tetraspanin expressed on malignant B cells. Recently, CD37 has gained interest as a therapeutic target. We developed AGS67E, an antibody-drug conjugate that targets CD37 for the potential treatment of B/T-cell malignancies.

Discoidin domain receptor 1 contributes to tumorigenesis through modulation of TGFBI expression.

Discoidin domain receptor 1 (DDR1) is a member of the receptor tyrosine kinase family. The receptor is activated upon binding to its ligand, collagen, and plays a crucial role in many fundamental processes such as cell differentiation, adhesion, migration and invasion. Although DDR1 is expressed in many normal tissues, upregulated expression of DDR1 in a variety of human cancers such as lung, colon and brain cancers is known to be associated with poor prognosis.

Using the Lessons Learned From the Clinic to Improve the Preclinical Development of Antibody Drug Conjugates.

The treatment options for cancer patients include surgery, chemotherapeutics, radiation therapy, antibody therapy and various combinations of these therapies. The challenge with each therapy is finding the balance between maximizing the anti-tumor efficacy while minimizing the dose limiting toxicities. Antibodies, unlike small molecule chemotherapeutics, selectively bind to cell surface tumor antigens and can be used to deliver radionucleotides or small molecule chemotherapeutic drugs directly to the tumor.

In vitro and in vivo evaluation of cysteine and site specific conjugated herceptin antibody-drug conjugates.

Antibody drug conjugates (ADCs) are monoclonal antibodies designed to deliver a cytotoxic drug selectively to antigen expressing cells. Several components of an ADC including the selection of the antibody, the linker, the cytotoxic drug payload and the site of attachment used to attach the drug to the antibody are critical to the activity and development of the ADC. The cytotoxic drugs or payloads used to make ADCs are typically conjugated to the antibody through cysteine or lysine residues.

Inhibition of tumorigenesis driven by different Wnt proteins requires blockade of distinct ligand-binding regions by LRP6 antibodies.

Disregulated Wnt/beta-catenin signaling has been linked to various human diseases, including cancers. Inhibitors of oncogenic Wnt signaling are likely to have a therapeutic effect in cancers. LRP5 and LRP6 are closely related membrane coreceptors for Wnt proteins.

Anti-DKK1 mAb (BHQ880) as a potential therapeutic agent for multiple myeloma.

Decreased activity of osteoblasts (OBs) contributes to osteolytic lesions in multiple myeloma (MM). The production of the soluble Wnt inhibitor Dickkopf-1 (DKK1) by MM cells inhibits OB activity, and its serum level correlates with focal bone lesions in MM. Therefore, we have evaluated bone anabolic effects of a DKK1 neutralizing antibody (BHQ880) in MM.

Serum concentrations of DKK-1 decrease in patients with multiple myeloma responding to anti-myeloma treatment.

Lytic bone destruction is a hallmark of multiple myeloma (MM) and is because of an uncoupling of bone remodeling. Secretion of Dickkopf (DKK)-1 by myeloma cells is a major factor which causes inhibition of osteoblast precursors. In this study, the effect of different treatment regimens for MM on serum DKK-1 was evaluated and correlated with the response to treatment in 101 myeloma patients receiving bortezomib, thalidomide, lenalidomide, adriamycin and dexamethasone (AD) or high-dose chemotherapy (HDCT) followed by autologous stem cell transplantation (ASCT).

Inhibiting Dickkopf-1 (Dkk1) removes suppression of bone formation and prevents the development of osteolytic bone disease in multiple myeloma.

Multiple myeloma (MM) is associated with the development of osteolytic bone disease, mediated by increased osteoclastic bone resorption and impaired osteoblastic bone formation. Dickkopf-1 (Dkk1), a soluble inhibitor of wingless/int (Wnt) signaling and osteoblastogenesis, is elevated in patients with MM and correlates with osteolytic bone disease. In this study, we investigated the effect of inhibiting Dkk1 on the development of osteolytic lesions in the 5T2MM murine model of myeloma.

Serum concentrations of DKK-1 correlate with the extent of bone disease in patients with multiple myeloma.

Objectives: Lytic bone disease is a hallmark of multiple myeloma (MM) and is caused by osteoclast activation and osteoblast inhibition. Secretion of Dickkopf (DKK)-1 by myeloma cells is a major factor which causes inhibition of osteoblast precursors. So far, there is no study showing a significant difference in serum DKK-1 levels in MM patients with or without lytic bone lesions.

TRAIL signals to apoptosis in chronic lymphocytic leukaemia cells primarily through TRAIL-R1 whereas cross-linked agonistic TRAIL-R2 antibodies facilitate signalling via TRAIL-R2.

Tumour necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL), a member of the TNF family, which is being developed as an anti-tumour agent due to its selective toxicity to tumour cells, induces apoptosis by binding to two membrane-bound receptors, TRAIL-R1 and TRAIL-R2. Clinical trials have been initiated with various preparations of TRAIL as well as agonistic monoclonal antibodies to TRAIL-R1 and TRAIL-R2. Previously we reported that prior treatment of primary chronic lymphocytic leukaemia (CLL) cells with histone deacetylase inhibitors was required to sensitize CLL cells to TRAIL and, using various receptor-selective TRAIL mutant ligands, we demonstrated that CLL cells signalled to apoptosis primarily through TRAIL-R1.

Novel magnetic supports for small molecule affinity capture of proteins for use in proteomics.

Magnetic supports are tested for use in batch affinity capture of proteins. Two types of magnetic polymer composites were used for solid phase synthesis and for the batch affinity chromatography of folate binding protein from a protein mixture. Gly-Gly-L-Methotrexate as well as other analogs were synthesized on magnetic supports consisting of either polyoxyalkyleneamine grafted onto polystyrene beads or a copolymer of polyethylene glycol dimethylacrylamide (PEGA).