In vivo biotinylation of the vasculature in B-cell lymphoma identifies BST-2 as a target for antibody-based therapy

Abstract

The discovery of accessible markers of lymphoma may facilitate the development of antibody-based therapeutic strategies. Here, we describe the results of a chemical proteomic study, based on the in vivo biotinylation of vascular proteins in lymphoma-bearing mice followed by mass spectrometric and bioinformatic analysis, to discover proteins expressed at the tissue-blood border of disseminated B-cell lymphoma. From a list of 58 proteins, which were more than 10-fold up-regulated in nodal and extranodal lymphoma lesions compared with their levels in the corresponding normal host organs, we validated BST-2 as a novel vascular marker of B-cell lymphoma, using immunochemical techniques and in vivo biodistribution studies. Furthermore, targeting BST-2 with 2 independent monoclonal antibodies delayed lymphoma growth in a syngeneic mouse model of the disease. The results of this study delineate a strategy for the treatment of systemic B-cell lymphoma in humans and suggest that anti-BST-2 antibodies may facilitate pharmacodelivery approaches that target the tumor-stroma interface. (Blood. 2010;115: 736-744) IntroductionMonoclonal antibodies are increasingly being used in modern anticancer therapy either as intact immunoglobulins or as carriers for the selective delivery of bioactive molecules (eg, drugs with cleavable linkers, radionuclides, cytokines) to the tumor site, thereby minimizing exposure to noninvolved organs. [1][2][3][4][5][6] Initially, site-directed cancer therapies have mainly aimed at targeting antigens expressed on the surface of cancer cells. However, tumor cells embedded in large tumor masses are not readily accessible to antibodies from the bloodstream, 7 an obstacle that may reduce their in vivo therapeutic efficacy despite a sufficient activity in vitro. Recently, pharmacodelivery strategies have been developed that target molecules expressed in tumor blood vessels or in the tumor stroma. 1,3,6 Indeed, structures in the immediate vicinity of the tissue-blood border are not only inherently accessible to blood-borne agents but also allow some unique therapeutic options. For example, the angiogenic endothelium appears exceptionally suited for the selective shutdown of a tumor's blood supply. 8 Components of the subendothelial extracellular matrix are often more abundantly expressed, permitting an efficient antibody-mediated deposition of bioactive payloads at the tumor site. [9][10][11][12][13][14] Antibody-based pharmacodelivery strategies are particularly attractive for the therapy of hematologic malignancies, in light of the fact that patients with leukemias or lymphomas commonly experience serious side effects from conventional induction chemotherapies. The advent of monoclonal antibodies specific to certain CD antigens represented a significant step toward a more specific therapy of these malignancies, either unconjugated (eg, rituximab or alemtuzumab) or as carriers for cytotoxic drugs (eg, gemtuzumab ozogamicin) or radionuclides (eg, ibritumomab tiuxetan). 15 Whereas cell-surface antigens have ...

Interfering with pH regulation in tumours as a therapeutic strategy

“…The alternatively spliced domains extra domain A (EDA) and extra domain B (EDB) of fibronectin, which are targeted by the F8 and L19 antibodies, respectively, exhibit a high level of conservation among species and are virtually undetectable in normal tissues; however, they are abundantly expressed in the stroma and neovasculature of most aggressive types of human cancers 96,[102][103][104][105][106][107][108][109][110] . Similarly, systematic chemical proteomics studies 107,[111][112][113] have recently shown that another component of the extracellular matrix, periostin, exists in several splice isoforms that are abundantly found in most types of cancers [111][112][113][114] . 42,43 or using nanoparticles to design CAIs 44 .…”

Antibody-Radionuclide Conjugates for Cancer Therapy: Historical Considerations and New Trends

“…In this case, vessel/blood radioactivity ratios may be predictive of the relative damage caused by a particles to endothelial cells and blood cells. immunohistochemistry), transcriptomic studies, in vivo phage library panning (44), and perfusion-based mass spectrometry-assisted techniques (45)(46)(47). We have developed human monoclonal antibodies (L19, F8, and F16) specific to splice isoforms of fibronectin and tenascin-C, which represent some of the most extensively characterized markers of tumor angiogenesis known so far (42).…”

“…Of interest, it was recently discovered that fibronectin and tenascin-C isoforms are abundant not only in the majority of solid tumors but also around the neovasculature of most lymphoma types (47,50,51). The L19 antibody in SIP format and labeled with 131 I has shown promising results for the radioimmunotherapy of refractory Hodgkin's lymphoma patients, and more than 100 cancer patients have already been treated with this agent (Fig.…”

Using Clinical Proteomics to Discover Novel Anti-Cancer Targets for MAb Therapeutics

“…The resulting biotinylated proteins can then be easily recovered using streptavidin followed by on-resin proteolyitic digestion and HPLC and finally mass spectrometry to identify proteins assessable in the circulatory system. This technique led to the identification of BST-2 as a novel target for antibody-based therapy (Schliemann, Roesli et al 2010). Numerous proteomic techniques have been used over the years to discover new targets such as a phage display protocol where by mice are injected with a phage library and tissues excised and phage bound are identified (Pasqualini and Ruoslahti 1996).…”