HIV Envelope Glycoform Heterogeneity and Localized Diversity Govern the Initiation and Maturation of a V2 Apex Broadly Neutralizing Antibody Lineage.

Understanding how broadly neutralizing antibodies (bnAbs) to HIV envelope (Env) develop during natural infection can help guide the rational design of an HIV vaccine. Here, we described a bnAb lineage targeting the Env V2 apex and the Ab-Env co-evolution that led to development of neutralization breadth. The lineage Abs bore an anionic heavy chain complementarity-determining region 3 (CDRH3) of 25 amino acids, among the shortest known for this class of Abs, and achieved breadth with only 10% nucleotide somatic hypermutation and no insertions or deletions. The data suggested a role for Env glycoform heterogeneity in the activation of the lineage germline B cell. Finally, we showed that localized diversity at key V2 epitope residues drove bnAb maturation toward breadth, mirroring the Env evolution pattern described for another donor who developed V2-apex targeting bnAbs. Overall, these findings suggest potential strategies for vaccine approaches based on germline-targeting and serial immunogen design.

MOR209/ES414, a Novel Bispecific Antibody Targeting PSMA for the Treatment of Metastatic Castration-Resistant Prostate Cancer.

Treatment of metastatic, castration-resistant prostate cancer (mCRPC) remains a highly unmet medical need and current therapies ultimately result in disease progression. Immunotherapy is a rapidly growing approach for treatment of cancer but has shown limited success to date in the treatment of mCRPC. We have developed a novel humanized bispecific antibody, MOR209/ES414, built on the ADAPTIR (modular protein technology) platform, to redirect T-cell cytotoxicity toward prostate cancer cells by specifically targeting T cells through CD3ε to prostate cancer cells expressing PSMA (prostate-specific membrane antigen). In vitro cross-linking of T cells with PSMA-expressing tumor cells by MOR209/ES414 triggered potent target-dependent tumor lysis and induction of target-dependent T-cell activation and proliferation. This activity occurred at low picomolar concentrations of MOR209/ES414 and was effective at low T-effector to tumor target cell ratios. In addition, cytotoxic activity was equivalent over a wide range of PSMA expression on target cells, suggesting that as few as 3,700 PSMA receptors per cell are sufficient for tumor lysis. In addition to high sensitivity and in vitro activity, MOR209/ES414 induced limited production of cytokines compared with other bispecific antibody formats. Pharmacokinetic analysis of MOR209/ES414 demonstrated a serum elimination half-life in NOD/SCID γ (NSG) mice of 4 days. Administration of MOR209/ES414 in murine xenograft models of human prostate cancer significantly inhibited tumor growth, prolonged survival, and decreased serum prostate-specific antigen levels only in the presence of adoptively transferred human T cells. On the basis of these preclinical findings, MOR209/ES414 warrants further investigation as a potential therapeutic for the treatment of CRPC. Mol Cancer Ther; 15(9); 2155-65. ©2016 AACR.

Expression of alpha-methylacyl-CoA racemase (P504s) in various malignant neoplasms and normal tissues: astudy of 761 cases.

Alpha-methylacyl CoA racemase (AMACR), also known as P504S, plays an important role in peroxisomal beta-oxidation of branched-chain fatty acids. It has recently been shown that AMACR is highly expressed in prostate cancer and that it may be an important diagnostic marker for prostate carcinoma. However, little is known about expression of AMACR in normal tissues and other malignant tumors. In this study, we investigated expression of AMACR in 539 malignant tumors and 222 normal human tissues of various types by immunohistochemical analysis. mRNA levels of AMACR in normal organs and in selected tumors were assessed by real time PCR. In normal tissue, high expression of AMACR mRNA was identified in liver, kidney and salivary gland, while AMACR protein was detected in liver (hepatocytes), kidney (tubular epithelial cells), lung (only bronchial epithelial cells), and gallbladder (only mucosal epithelial cells). High expression of AMACR mRNA was found in prostate, liver, and kidney cancers but rarely in stomach and bladder cancers. A high percent of adenocarcinomas arising from these organs express AMACR, including 17 of 21 (81%) of hepatocellular carcinomas and 18 of 24 (75%) of renal cell carcinomas. In addition, carcinomas arising from tissues normally not expressing AMACR were also positive for the antigen, including 17 of 18 (94%) prostate carcinomas, 9 of 29 (31%) of urothelial carcinomas, and 4 of 15 (27%) of gastric adenocarcinomas. Two hundred and fifty cases of adenocarcinomas from lung, breast, pancreas, bile duct, adrenal gland, salivary gland, ovary, thyroid and endometrium were negative or rarely positive for AMACR. Neuroendocrine carcinomas rarely expressed AMACR. Melanomas, squamous cell carcinomas, basal cell carcinomas, soft tissue tumors (including epithelioid sarcomas and synovial sarcoma), thymomas, and germ cell tumors were negative for AMACR. Our data provide important baseline information for using AMACR in clinical practice and also are valuable in furthering understanding of the pathogenic role of AMACR in malignant neoplasms.

Glycovariant anti-CD37 monospecific protein therapeutic exhibits enhanced effector cell-mediated cytotoxicity against chronic and acute B cell malignancies.

TRU-016 is a SMIP(TM) (monospecific protein therapeutic) molecule against the tetraspanin transmembrane family protein CD37 that is currently in Phase 2 trials in Chronic Lymphocytic Leukemia (CLL) and Non-Hodgkin Lymphoma (NHL). In an attempt to enhance the ADCC function of SMIP-016, the chimeric version of TRU-016, SMIP-016(GV) was engineered with a modification in a glycosylation site in the Fc domain. The wild-type and glycovariant SMIP proteins mediate comparable Type I antibody-like direct cytotoxicity in the presence of anti-human Fc crosslinker and show a similar tyrosine phosphorylation pattern post-treatment. However, NK cells stimulated with the SMIP-016(GV) exhibit enhanced activation and release 3-fold more interferon-γ compared with SMIP-016. SMIP-016(GV) shows enhanced ADCC function against cells expressing CD37 with NK cell effectors derived from both normal and CLL-affected individuals. Enhanced ADCC is observed against CLL cells and is sustained at concentrations of SMIP-016(GV) as low at 5E(-6) µg/mL on cells expressing minimal CD37 antigen. In support of the biological relevance of this, SMIP-016(GV) mediates effective ADCC against primary acute lymphoblastic leukemia (ALL) cells with low surface expression of CD37. Collectively, these data suggest potential use of the novel therapeutic agent SMIP-016(GV) with enhanced effector function for B cell malignancies, including CLL and ALL therapy.

Tetraspanin CD37 directly mediates transduction of survival and apoptotic signals.

Tetraspanins are commonly believed to act only as "molecular facilitators," with no direct role in signal transduction. We herein demonstrate that upon ligation, CD37, a tetraspanin molecule expressed on mature normal and transformed B cells, becomes tyrosine phosphorylated, associates with proximal signaling molecules, and initiates a cascade of events leading to apoptosis. Moreover, we have identified two tyrosine residues with opposing regulatory functions: one lies in the N-terminal domain of CD37 in a predicted "ITIM-like" motif and mediates SHP1-dependent death, whereas the second lies in a predicted "ITAM motif" in the C-terminal domain of CD37 and counteracts death signals by mediating phosphatidylinositol 3-kinase-dependent survival.

A dietary enzyme: alpha-methylacyl-CoA racemase/P504S is overexpressed in colon carcinoma.

Epidemiological studies have shown that consumption of red meat increases the risk of developing colon cancer. An enzyme, alpha-methylacyl CoA racemase (AMACR), also known as P504S, plays an important role in peroxisomal beta-oxidation of branched-chain fatty acids from red meat and dairy products. High expression of AMACR was recently found in prostate cancer. In this study, we investigated expression of AMACR in 242 cases of colonic tumors including 176 colorectal carcinomas, 38 colon adenomas and 28 hyperplastic (non-neoplastic) polyps by immunohistochemical analysis. The mRNA levels of AMACR expression in normal and colon cancer tissues were assessed by real-time PCR. Significant up-regulation of AMACR mRNA was found in colon carcinomas compared to normal tissue. There was very low or no expression of AMACR protein in normal colon, but AMACR was highly expressed in 76 and 75% of well and moderately differentiated colon carcinomas, respectively, and in 79% of adenomas. In contrast, only 4% of hyperplastic polyps expressed AMACR. Since this enzyme is involved in the metabolism of branched-chain fatty acids from beef, milk and dairy products, our results provide important molecular information regarding a possible link between diet and development of colon cancer. AMACR may also serve as a molecular marker for colon cancers and its precursor lesions.