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Translation of drug candidates into clinical settings requires demonstration of preclinical efficacy and formal toxicology analysis for filling an Investigational New Drug (IND) application with the US Food and Drug Administration (FDA). Here, we investigate the membrane-associated glucose response protein 78 (GRP78) as a therapeutic target in leukemia and lymphoma. We evaluated the efficacy of the GRP78-targeted proapoptotic drug bone metastasis targeting peptidomimetic 78 (BMTP-78), a member of the D (KLAKLAK)2-containing class of agents. BMTP-78 was validated in cells from patients with acute myeloid leukemia and in a panel of human leukemia and lymphoma cell lines, where it induced dose-dependent cytotoxicity in all samples tested. Based on the in vitro efficacy of BMTP-78, we performed formal good laboratory practice toxicology studies in both rodents (mice and rats) and nonhuman primates (cynomolgus and rhesus monkeys). These analyses represent required steps towards an IND application of BMTP-78 for theranostic first-in-human clinical trials.

Human prostate cancer often metastasizes to bone, but the biological basis for such site-specific tropism remains largely unresolved. Recent work led us to hypothesize that this tropism may reflect pathogenic interactions between RAGE, a cell surface receptor expressed on malignant cells in advanced prostate cancer, and proteinase 3 (PR3), a serine protease present in inflammatory neutrophils and hematopoietic cells within the bone marrow microenvironment. In this study, we establish that RAGE–PR3 interaction mediates homing of prostate cancer cells to the bone marrow. PR3 bound to RAGE on the surface of prostate cancer cells in vitro, inducing tumor cell motility through a nonproteolytic signal transduction cascade involving activation and phosphorylation of ERK1/2 and JNK1. In preclinical models of experimental metastasis, ectopic expression of RAGE on human prostate cancer cells was sufficient to promote bone marrow homing within a short timeframe. Our findings demonstrate how RAGE–PR3 interactions between human prostate cancer cells and the bone marrow microenvironment mediate bone metastasis during prostate cancer progression, with potential implications for prognosis and therapeutic intervention. Cancer Res; 77(12); 3144–50. ©2017 AACR.

Background: Treating asthmatics with the humanized IgE-scavenging antibody, omalizumab (rhuMAb-E25, Xolair®), reduces airways inflammation and asthma symptoms. Previously, omalizumab was shown to cause a dramatic and reversible loss of cell surface high-affinity IgE receptors, FcΕRI, from the peripheral blood basophils of asthmatics. The consequences of receptor loss for the FcΕRI-mediated synthesis and release of cytokines implicated in allergic asthma have not been examined. Methods: Fifteen asthmatic volunteers each received omalizumab for 12 weeks. Peripheral blood basophils were isolated before, during, 2 weeks after and 6 months after omalizumab. Basophils were assayed for the basal and anti-IgE-stimulated release of cytokines, chemokines and histamine. Pooled data were analyzed by repeated measures ANOVA and by paired t tests. Results: Anti-IgE-stimulated human basophils synthesize and release Th2 cytokines (IL-4, IL-13) and chemokines (IL-8, RANTES). The anti-IgE-stimulated release of IL-4, IL-13 and IL-8 was reduced during omalizumab treatment and returned to pretreatment levels after omalizumab withdrawal. Omalizumab did not alter basophil histamine levels or basal and anti-IgE-stimulated histamine release. Conclusions: Omalizumab may reduce asthma symptoms in part by suppressing the FcΕRI-mediated production by basophils of Th2 cytokines and selected chemokines. Anti-IgE-stimulated basophil cytokine synthesis appears more sensitive than histamine release to the loss of FcΕRI caused by omalizumab treatment.