No abstract

Using structure based genome mining targeting vascular endothelial and platelet derived growth factor immunoglobulin (Ig) like folds, we have identified a sequence corresponding to a single transmembrane protein with two Ig domains, which we cloned from a human brain cDNA library. The cDNA is identical to hepatocyte cell adhesion molecule (hepaCAM), which was originally described as a tumor suppressor gene in liver. Here, we show that the protein is predominantly expressed in the mouse and human nervous system. In liver, the expression is very low in humans, and is not detected in mice. To identify the central nervous system (CNS) regions and cell types expressing the protein, we performed a LacZ reporter gene assay on heterozygous mice in which one copy of the gene encoding the novel protein had been replaced with beta-galactosidase. beta-galactosidase expression was prominent in white matter tracts of the CNS. Furthermore, expression was detected in ependymal cells of the brain ventricular zones and the central canal of the spinal cord. Double labeling experiments showed expression mainly in CNPase positive oligodendrocytes (OL). Since the protein is predominantly expressed in the CNS glial cells, we named the molecule glial cell adhesion molecule (GlialCAM). A potential role for GlialCAM in myelination was supported by its up-regulation during postnatal mouse brain development, where it was concomitantly expressed with myelin basic protein (MBP). In addition, in vitro, GlialCAM was observed in various developmental stages of OL and in astrocytes in processes and at cell contact sites. In A2B5 positive OL, GlialCAM colocalizes with GAP43 in OL growth cone like structures. Overall, the data presented here indicate a potential function for GlialCAM in glial cell biology.

In order to fully understand biological processes it is essential to identify interactions in protein complexes. There are several techniques available to study this type of interactions, such as yeast two-hybrid screens, affinity chromatography, and coimmunoprecipitation. We propose a novel strategy to identify protein-protein interactions, comprised of first detecting the interactions using ProteinChips and SELDI-TOF MS, followed by the isolation of the interacting proteins through affinity beads and RP-HPLC and finally identifying the proteins using nano-LC MS/MS. The advantages of this new strategy are that the primary high-throughput screening of samples can be performed with small amounts of sample, no specific antibody is needed and the proteins represented on the SELDI-TOF MS spectra can be identified with high confidence. Furthermore, the method is faster and less labor-intensive than other current approaches. Using this novel method, we isolated and identified the interactions of two mouse plasma proteins, mannose binding lectin C and properdin, with GlialCAM, a type 1 transmembrane glycoprotein that belongs to the Ig superfamily.

No abstract

TPS8054 Background: DARA, a monoclonal antibody (mAb) against CD38, is approved for RRMM. Combination treatment (Tx) with DARA + DURVA, a mAb against programmed death ligand-1 (PD-L1), may enhance host anti-MM immunity and response. DARA and PD-L1 mAbs have each demonstrated clinical activity in combination with pomalidomide (POM) + low-dose dexamethasone (LoDEX) in MM. Thus, the phase 2 MEDI4736-MM-003 trial is evaluating DURVA + DARA in RRMM, and, in an exploratory analysis, the addition of POM + LoDEX to DARA + DURVA either upon progressive disease (PD) with DARA + DURVA or as up-front Tx will be assessed. Methods: ≈ 144 pts with RRMM are being enrolled. Pts with measurable MM who received ≥ 3 prior anti-MM Txs, including a protease inhibitor and an immunomodulatory agent, or are double-refractory to these 2 agents will be included. Exclusion criteria include allogeneic stem cell transplant (SCT), autologous SCT ≤ 12 weeks, and prior DARA or other CD38 antibody therapies. Primary endpoints are overall response rate (ORR) and safety. Secondary endpoints are time to response, duration of response, progression-free survival, and pharmacokinetics. The study includes a 3 + 3 safety run-in phase to confirm the tolerability of the recommended phase 2 doses (RP2Ds) of DURVA and DARA. Dose-limiting toxicities will be evaluated during the first Tx cycle. Safety and efficacy will be assessed by a Simon 2-stage design (Table). POM + LoDEX may be added to DARA + DURVA in pts who received ≥ 2 cycles of DARA + DURVA and had confirmed PD. Based on preliminary safety and efficacy, the 4-drug regimen may be explored as up-front Tx. Tx with either the 2- or 4-drug regimens will continue until PD or unacceptable toxicity. Pts treated with POM will be followed for second primary malignancies every 6 mos until the end of the trial. To date, 6 pts have enrolled in the run-in phase. Clinical trial information: NCT02807454. [Table: see text]