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International audience; Breast cancer (BC) is the most common form of cancer among women worldwide. Despite the huge advancements in its treatment, the exact etiology of breast cancer still remains unresolved. There is an increasing interest in the role of the gut microbiome in modulating the anti-cancer therapeutic response. It seems that alteration of the microbiome-derived metabolome potentially promotes carcinogenesis. Taken together, metabolomics has arisen as a fascinating new omics field to screen promising metabolic biomarkers. In this study, fecal metabolite profiling was performed using NMR spectroscopy, to identify potential biomarker candidates that can predict response to neoadjuvant chemotherapy (NAC) for breast cancer. Metabolic profiles of feces from patients (n = 8) following chemotherapy treatment cycles were studied. Interestingly, amino acids were found to be upregulated, while lactate and fumaric acid were downregulated in patients under the second and third cycles compared with patients before treatment. Furthermore, short-chain fatty acids (SCFAs) were significantly differentiated between the studied groups. These results strongly suggest that chemotherapy treatment plays a key role in modulating the fecal metabolomic profile of BC patients. In conclusion, we demonstrate the feasibility of identifying specific fecal metabolic profiles reflecting biochemical changes that occur during the chemotherapy treatment. These data give an interesting insight that may complement and improve clinical tools for BC monitoring.

The general stress response in Enterobacteria, like Escherichia coli or Salmonella, is controlled by the transcription factor σS, encoded by the rpoS gene, which accumulates during stationary phase growth and associates with the core RNA polymerase enzyme (E) to promote transcription of genes involved in cell survival. Tight regulation of σS is essential to preserve the balance between self-preservation under stress conditions and nutritional competence in the absence of stress. Whereas σ factors are generally inactivated upon interaction with anti-sigma proteins, σS binding by the Crl protein facilitates the formation of the holoenzyme EσS, and therefore σS-controlled transcription. Previously, critical residues in both Crl and σS were identified and assigned to the binding interface in the Crl–σS complex. However, high-resolution structural data are missing to fully understand the molecular mechanisms underlying σS activation by Crl, in particular the possible role of Crl in triggering domain rearrangements in the multi-domain protein σS. Here we provide the 1H, 13C and 15N resonance assignments of Salmonella enterica serovar Typhimurium Crl, as a starting point for CrlSTM structure determination and further structural investigation of the CrlSTM–σ STM S complex.