Screening of a Library of Oligosaccharides Targeting Lectin LecB of Pseudomonas Aeruginosa and Synthesis of High Affinity Oligoglycoclusters.

The Gram negative bacterium Pseudomonas aeruginosa (PA) is an opportunistic bacterium that causes severe and chronic infection of immune-depressed patients. It has the ability to form a biofilm that gives a selective advantage to the bacteria with respect to antibiotherapy and host defenses. Herein, we have focused on the tetrameric soluble lectin which is involved in bacterium adherence to host cells, biofilm formation, and cytotoxicity. It binds to l-fucose, d-mannose and glycan exposing terminal fucose or mannose. Using a competitive assay on microarray, 156 oligosaccharides and polysaccharides issued from fermentation or from the biomass were screened toward their affinity to LecB. Next, the five best ligands (Lewisa, Lewisb, Lewisx, siayl-Lewisx and 3-fucosyllactose) were derivatized with a propargyl aglycon allowing the synthesis of 25 trivalent, 25 tetravalent and 5 monovalent constructions thanks to copper catalyzed azide alkyne cycloaddition. The 55 clusters were immobilized by DNA Directed immobilization leading to the fabrication of a glycocluster microarray. Their binding to LecB was studied. Multivalency improved the binding to LecB. The binding structure relationship of the clusters is mainly influenced by the carbohydrate residues. Molecular simulations indicated that the simultaneous contact of both binding sites of monomer A and D seems to be energetically possible.

Therapeutic Challenges in Patients with Gynecologic Carcinosarcomas: Analysis of a Multicenter National Cohort Study from the French Prospective TMRG Network.

BACKGROUND: Gynecological carcinosarcomas are rare and aggressive diseases, with a poor prognosis. The rarity of these tumors explains the lack of robust and specific data available in the literature. The objective of this study was to investigate the impact of initial adjuvant treatment and recurrent therapeutic strategies. PATIENTS AND METHODS: A multicentric cohort study within the French national prospective Rare Malignant Gynecological Tumors (TMRG) network was conducted. Data from all included carcinosarcomas diagnosed between 2011 and 2018 were retrospectively collected. RESULTS: 425 cases of uterine and ovarian carcinosarcomas (n = 313 and n = 112, respectively) were collected and analyzed from 12 participating centers. At diagnosis, 140 patients (48%) had a FIGO stage III-IV uterine carcinosarcoma (UCS) and 88 patients (83%) had an advanced ovarian carcinosarcoma (OCS) (FIGO stage ≥ III). Two hundred sixty-seven patients (63%) received adjuvant chemotherapy, most preferably carboplatin-paclitaxel regimen (n = 227, 86%). After a median follow-up of 47.4 months, the median progression-free survival (mPFS) was 15.1 months (95% CI 12.3-20.6) and 14.8 months (95% CI 13.1-17.1) for OCS and UCS, respectively. The median overall survival for OCS and UCS was 37.1 months (95% CI 22.2-49.2) and 30.6 months (95% CI 24.1-40.9), respectively. With adjuvant chemotherapy followed by radiotherapy, mPFS was 41.0 months (95% CI 17.0-NR) and 18.9 months (95% CI 14.0-45.6) for UCS stages I-II and stages III-IV, respectively. In the early stage UCS subgroup (i.e., stage IA, n = 86, 30%), mPFS for patients treated with adjuvant chemotherapy (n = 24) was not reached (95% CI 22.2-NR), while mPFS for untreated patients (n = 62) was 19.9 months (95% IC 13.9-72.9) (HR 0.44 (0.20-0.95) p = 0.03). At the first relapse, median PFS for all patients was 4.2 months (95% CI 3.5-5.3). In the first relapse, mPFS was 6.7 months (95% CI 5.1-8.5) and 2.2 months (95% CI 1.9-2.9) with a combination of chemotherapy or monotherapy, respectively (p < 0.001). CONCLUSIONS: Interestingly, this vast prospective cohort of gynecological carcinosarcoma patients from the French national Rare Malignant Gynecological Tumors network (i) highlights the positive impact of adjuvant CT on survival in all localized stages (including FIGO IA uterine carcinosarcomas), (ii) confirms the importance of platinum-based combination as an option for relapse setting, and (iii) reports median PFS for various therapeutic strategies in the relapse setting.

Chemo-bacterial synthesis and immunoreactivity of a brain HNK-1 analogue.

This work reports the synthesis and the biological validation of a trisaccharide analogue of the HNK-1 epitope. The 3-O-sulfo-ß-d-GlcpA-(1→3)-ß-d-Galp-(1→4)-ß-d-Glcp-allyl has been prepared by enzymatic glucuronylation of allyl lactoside by an engineered recombinant Escherichia coli strain followed by a chemoselective sulfation. Subsequent covalent attachment of the ozone-oxidised trisaccharide to bovine serum albumin provided a neo-glycoconjugate, which has been interrogated with antibodies specific to the human natural killer carbohydrate epitope HNK-1. ELISA assays confirmed the absolute requirement of the sulfate group for protein recognition and the potential application of this synthetic oligosaccharide as HNK-1 surrogate.