Biocatalytic production of bicyclic β-lactams with three contiguous chiral centres using engineered crotonases

YesThere is a need to develop asymmetric routes to functionalised β-lactams, which remain the most important group of antibacterials. Here we describe biocatalytic and protein engineering studies concerning carbapenem biosynthesis enzymes, aiming to enable stereoselective production of functionalised carbapenams with three contiguous chiral centres. Structurallyguided substitutions of wildtype carboxymethylproline synthases enable tuning of their C-N and C-C bond forming capacity to produce 5-carboxymethylproline derivatives substituted at C-4 and C-6, from amino acid aldehyde and malonyl-CoA derivatives. Use of tandem enzyme incubations comprising an engineered carboxymethylproline synthase and an alkylmalonylCoA forming enzyme (i.e. malonyl-CoA synthetase or crotonyl-CoA carboxylase reductase) can improve stereocontrol and expand the product range. Some of the prepared 4,6-disubstituted-5-carboxymethylproline derivatives are converted to bicyclic β-lactams by carbapenam synthetase catalysis. The results illustrate the utility of tandem enzyme systems involving engineered crotonases for asymmetric bicyclic β-lactam synthesis

Accurate prediction of response to endocrine therapy in breast cancer patients: current and future biomarkers

WOS: 000390900700001PubMed ID: 27903276Approximately 70% of patients have breast cancers that are oestrogen receptor alpha positive (ER+) and are therefore candidates for endocrine treatment. Many of these patients relapse in the years during or following completion of adjuvant endocrine therapy. Thus, many ER+ cancers have primary resistance or develop resistance to endocrine therapy during treatment. Recent improvements in our understanding of how tumours evolve during treatment with endocrine agents have identified both changes in gene expression and mutational profiles, in the primary cancer as well as in circulating tumour cells. Analysing these changes has the potential to improve the prediction of which specific patients will respond to endocrine treatment. Serially profiled biopsies during treatment in the neoadjuvant setting offer promise for accurate and early prediction of response to both current and novel drugs and allow investigation of mechanisms of resistance. In addition, recent advances in monitoring tumour evolution through non-invasive (liquid) sampling of circulating tumour cells and cell-free tumour DNA may provide a method to detect resistant clones and allow implementation of personalized treatments for metastatic breast cancer patients. This review summarises current and future biomarkers and signatures for predicting response to endocrine treatment, and discusses the potential for using approved drugs and novel agents to improve outcomes. Increased prediction accuracy is likely to require sequential sampling, utilising preoperative or neoadjuvant treatment and/or liquid biopsies and an improved understanding of both the dynamics and heterogeneity of breast cancer.European CommissionEuropean Commission Joint Research Centre [658170]This work was funded by the European Commission H2020 Marie Sklodowska Curie Action Individual Fellowship (H2020-MSCA-IF, 658170) to CS and Breast Cancer Now to JMD and AHS

Overexpression of Desmoglein 2 in a mouse model of Gorlin syndrome enhances spontaneous basal cell carcinoma formation through STAT3-mediated Gli1 expression

Activation of the Hedgehog (Hh) pathway is causative of virtually all sporadic and Gorlin syndrome-related basal cell carcinomas (BCC), with loss of function of Patched1 (Ptc1) being the most common genomic lesion. Sporadic BCCs also overexpress desmoglein-2 (Dsg2), a desmosomal cadherin normally found in the basal layer. Using a mouse model of Gorlin syndrome (Ptc1+/lacZ mice), we found that overexpressing Dsg2 in the basal layer (K14-Dsg2/Ptc1+/lacZ) or the superficial epidermis (Inv-Dsg2/Ptc1+/lacZ mice) resulted in increased spontaneous BCC formation at 3 and 6 months, respectively. The tumors did not show loss of heterozygosity of Ptc1, despite high levels of Gli1 and phosphorylated Stat3. A panel of sporadic human BCCs showed increased staining of both Dsg2 and P-Stat3 in 9/9 samples. Overexpression of Dsg2 in ASZ001 cells, a Ptc1-/- BCC cell line, induced Stat3 phosphorylation and further increased Gli1 levels, both in an autocrine and paracrine manner. Three different Stat3 inhibitors reduced viability and Gli1 expression in ASZ001 cells, but not in HaCaT cells. Conversely, stimulation of Stat3 in ASZ001 cells with IL-6 increased Gli1 expression. Our results indicate that Dsg2 enhances canonical Hh signaling downstream of Ptc1 to promote BCC development through the activation of P-Stat3 and regulation of Gli1 expression

Whole-Genome Shotgun Sequencing of Two β‑Proteobacterial Species in Search of the Bulgecin Biosynthetic Cluster

We have produced draft whole-genome sequences for two bacterial strains reported to produce the bulgecins as well as NRPS-derived monobactam β-lactam antibiotics. We propose classification of ATCC 31363 as <i>Paraburkholderia acidophila.</i> We further reaffirm that ATCC 31433 (<i>Burkholderia ubonensis subsp. mesacidophila</i>) is a taxonomically distinct producer of bulgecins with notable gene regions shared with <i>Paraburkholderia acidophila.</i> We use RAST multiple-gene comparison and MASH distancing with published genomes to order the draft contigs and identify unique gene regions for characterization. Forty-eight natural-product gene clusters are presented from PATRIC (RASTtk) and antiSMASH annotations. We present evidence that the 10 genes that follow the sulfazecin and isosulfazecin pathways in both species are likely involved in bulgecin A biosynthesis

Preliminary tolerance analysis of adjuvant chemotherapy in older patients after resection of stage III colon cancer from the PRODIGE 34-FFCD randomized trial

International audienceBACKGROUND: Colon adenocarcinoma mainly occurs in older patients. Oxaliplatin-based adjuvant chemotherapy improved disease-free survival after stage III colon cancer resection, but this improvement was not demonstrated in older patients. METHODS: The purpose of ADAGE-PRODIGE 34, randomized open phase III trial is to compare in patients over 70 years oxaliplatin plus fluoropyrimidine with fluoropyrimidine alone in fit patients (Group 1) and fluoropyrimidine with observation in frail patients (Group 2) after resection of stage III colon adenocarcinoma. We report a preliminary tolerance analysis on 50% of the first patients enrolled. RESULTS: The analysis was conducted on 491 patients (378 in Group 1 and 113 in Group 2). Patients in Group 2 were older and showed more frailty criteria than those in Group 1. Cumulative grade 3-5 toxicities were more frequent in patients treated with oxaliplatin in Group 1 or with fluoropyrimidine in Group 2 than in patients treated with fluoropyrimidine in Group 1. At least one course was deferred in more than half of the patients in all groups. Early treatment cessation was more frequent in Group 2. CONCLUSION: No safety concerns were raised for the continuation of accrual. The frailty criteria distribution suggests that the investigator's evaluation for group allocation was accurate

Preliminary tolerance analysis of adjuvant chemotherapy in older patients after resection of stage III colon cancer from the PRODIGE 34-FFCD randomized trial

International audienceBACKGROUND: Colon adenocarcinoma mainly occurs in older patients. Oxaliplatin-based adjuvant chemotherapy improved disease-free survival after stage III colon cancer resection, but this improvement was not demonstrated in older patients. METHODS: The purpose of ADAGE-PRODIGE 34, randomized open phase III trial is to compare in patients over 70 years oxaliplatin plus fluoropyrimidine with fluoropyrimidine alone in fit patients (Group 1) and fluoropyrimidine with observation in frail patients (Group 2) after resection of stage III colon adenocarcinoma. We report a preliminary tolerance analysis on 50% of the first patients enrolled. RESULTS: The analysis was conducted on 491 patients (378 in Group 1 and 113 in Group 2). Patients in Group 2 were older and showed more frailty criteria than those in Group 1. Cumulative grade 3-5 toxicities were more frequent in patients treated with oxaliplatin in Group 1 or with fluoropyrimidine in Group 2 than in patients treated with fluoropyrimidine in Group 1. At least one course was deferred in more than half of the patients in all groups. Early treatment cessation was more frequent in Group 2. CONCLUSION: No safety concerns were raised for the continuation of accrual. The frailty criteria distribution suggests that the investigator's evaluation for group allocation was accurate