High-resolution structures reveal how a germline antibody can recognize a range of clinically relevant carbohydrate epitopes. The germline response to a carbohydrate immunogen can be critical to survivability, with selection for antibody gene segments that both confer protection against common pathogens and retain the flexibility to adapt to new disease organisms. We show here that antibody S25-2 binds several distinct inner-core epitopes of bacterial lipopolysaccharides (LPSs) by linking an inherited monosaccharide residue binding site with a subset of complementarity-determining regions (CDRs) of limited flexibility positioned to recognize the remainder of an array of different epitopes. This strategy allows germline antibodies to adapt to different epitopes while minimizing entropic penalties associated with the immobilization of labile CDRs upon binding of antigen, and provides insight into the link between the genetic origin of individual CDRs and their respective roles in antigen recognition.

AMG 386 combined with weekly paclitaxel was tolerable, with a manageable and distinct toxicity profile. The data suggest evidence of antitumor activity and a dose-response effect, warranting further studies in ovarian cancer.

Host interactions with tumor cells contribute to tumor progression by several means. This study was done to determine whether mammary epithelium could interact with breast carcinoma by producing substances capable of inducing motility in the cancer cells. Conditioned medium of immortalized 184A1 mammary epithelium collected in serum-free conditions induced dose-dependent motility in the MCF-7 breast carcinoma cell line by both a semiquantitative scattering assay and a Boyden chamber assay. Purification of the motility factor revealed that it was laminin 332 (formerly laminin 5) by mass spectroscopy. A Western blot of the 184A1 conditioned medium using a polyclonal antibody confirmed the presence of laminin 332 in the conditioned medium. Blockage of the motility with antibodies to the laminin 332 and its receptor components, alpha(3) and beta(1) integrins, provided further evidence that tumor cell motility was caused by the laminin 332 in the conditioned medium. Invasion of MCF-7, BT-20, and MDA-MB-435 S was induced by purified laminin 332 and 184A1 conditioned medium and blocked by an anti-alpha(3) integrin antibody. Staining of carcinoma in situ from breast cancer specimens revealed that laminin 332 in the myoepithelium adjacent to the preinvasive cells provided a source of laminin 332 that could potentially encourage the earliest steps of stromal invasion. In metaplastic breast carcinomas, the presence of laminin 332-producing cells coexpressing alpha(3) integrin and the greater metastatic potential of tumors with higher laminin 332 levels suggest that laminin 332 expression is associated with aggressive features in these human breast cancers.

No abstract

Objectives Gynecologic Oncology Group Study 0218 (GOG-0218), a phase III, placebo-controlled trial in newly diagnosed stage III/IV ovarian cancer (OC), demonstrated a benefit in investigator (INV)-assessed progression-free survival (PFS) with bevacizumab (BEV) administered with and following carboplatin/paclitaxel (CP) for up to 15 months vs. CP alone. To determine the reliability of Response Evaluation Criteria in Solid Tumors (RECIST) in assessing disease progression (PD) in GOG-0218, an independent review of radiologic and clinical data (IRC) was conducted. Methods Blinded reviews followed RECIST 1.0 in accordance with the study protocol; PFS was analyzed in the intent-to-treat population. Results CP + BEV→BEV achieved a significant PFS improvement in both assessments. Hazard ratios for PFS (IRC: 0.623; 95% confidence interval [CI]: 0.503–0.772; p<0.0001 vs. INV: 0.624; 95% CI: 0.520–0.749; p<0.0001) and the improvement in median PFS (IRC: 19.1 and 13.1 months vs. INV: 18.2 and 12 months) were similar between IRC and INV assessments. There was high concordance between IRC- and INV-determined PD status (77%) and date (73%). Subgroup analyses were consistent with the primary IRC findings. Early and late discontinuation discordance measures showed no evidence of INV bias. Conclusion IRC analysis confirmed a significant PFS improvement with CP + BEV → BEV vs. CP alone. Concordance was not influenced by extent of residual disease after cytoreductive surgery or initial stage. The IRC size, high participation rate, and strong concordance between IRC and INV assessments suggest that RECIST can be applied objectively in OC studies.

Human ABO(H) blood group glycosyltransferases GTA and GTB catalyze the final monosaccharide addition in the biosynthesis of the human A and B blood group antigens. GTA and GTB utilize a common acceptor, the H antigen disaccharide ␣-L-Fucp-(132)-␤-D-Galp-OR, but different donors, where GTA transfers GalNAc from UDP-GalNAc and GTB transfers Gal from UDP-Gal. GTA and GTB are two of the most homologous enzymes known to transfer different donors and differ in only 4 amino acid residues, but one in particular (Leu/Met-266) has been shown to dominate the selection between donor sugars. The structures of the A and B glycosyltransferases have been determined to high resolution in complex with two inhibitory acceptor analogs ␣-L-Fucp-(132)-␤-D-(3-deoxy)-Galp-OR and ␣-L-Fucp-(132)-␤-D-(3-amino)-Galp-OR, in which the 3-hydroxyl moiety of theGal ring has been replaced by hydrogen or an amino group, respectively. Remarkably, although the 3-deoxy inhibitor occupies the same conformation and position observed for the native H antigen in GTA and GTB, the 3-amino analog is recognized differently by the two enzymes. The 3-amino substitution introduces a novel intramolecular hydrogen bond between O 2 on Fuc and N3 on Gal, which alters the minimum-energy conformation of the inhibitor. In the absence of UDP, the 3-amino analog can be accommodated by either GTA or GTB with the L-Fuc residue partially occupying the vacant UDP binding site. However, in the presence of UDP, the analog is forced to abandon the intramolecular hydrogen bond, and the L-Fuc residue is shifted to a less ordered conformation. Further, the residue Leu/Met-266 that was thought important only in distinguishing between donor substrates is observed to interact differently with the 3-amino acceptor analog in GTA and GTB. These observations explain why the 3-deoxy analog acts as a competitive inhibitor of the glycosyltransferase reaction, whereas the 3-amino analog displays complex modes of inhibition.

No abstract

This paper presents a finite element formulation to study the mechanical buckling of stiffened functionally graded material (FGM) plates. The approach is based on a third-order shear deformation theory (TSDT) introduced by Guangyu Shi. The material properties of the plate were assumed to be varied in the thickness direction by a power law distribution, but the material of the stiffener was the same as that of the one of the bottom surface where the stiffener was placed. A parametric study was carried out to highlight the effect of material distribution, the thickness-to-width ratio, and stiffener parameters on the buckling characteristics of the stiffened FGM plates. Numerical results showed that the addition of stiffener to the FGM plate could significantly reduce the weight of the FGM plate but that both the FGM plates with and without stiffener had equally high strength in the same boundary condition and compression loading.