Biology subjects

Henriques, S. T.

Publications and source records attributed to Henriques, S. T..

3 recordsLinked to original sources

bioRxiv2022

Membrane-active peptides escape drug-resistance in cancer

Acquired drug-resistance is a recurring problem in cancer treatment, and this is particularly true for patients with metastatic melanoma that carry a BRAF V600E mutation. In the current study, we explored the use of membrane-active peptides as an alternative therapeutic modality to target drug-resistant melanoma cells. We produced slow-cycling and drug-resistant melanoma cells using dabrafenib, a small molecule drug that targets tumor cells with BRAF V600E mutation, and characterised their lipidome and proteome to investigate the role of membrane lipids in acquired drug-resistance. Despite some changes in the lipid composition, tested anti-melanoma membrane-active cyclic peptides (cTI and cGm) killed melanoma cells that are sensitive, tolerant, or resistant to dabrafenib. Importantly, melanoma cells did not develop resistance to cTI or cGm, nor changed their lipid composition with long-term peptide treatment. Therefore, these peptides are well suited as templates to design therapeutic leads to target drug-resistant metastatic melanoma cells and/or as co-treatment with small molecule drugs.

cancer biology↗

bioRxiv2022

OzFAD: Ozone-enabled fatty acid discovery reveals unexpected diversity in the human lipidome

Fatty acid isomers are responsible for an under-reported lipidome diversity across all kingdoms of life. Isomers of unsaturated fatty acid are often masked in contemporary analysis by incomplete separation and the absence of sufficiently diagnostic methods for structure elucidation. Here, we introduce a comprehensive workflow to discover new unsaturated fatty acids through coupling liquid chromatography and mass spectrometry with gas-phase ozonolysis of double bonds. The workflow encompasses semi-automated data analysis and enables de novo identification in complex media including human plasma, cancer cell lines and human sebaceous wax (i.e., vernix caseosa). The targeted analysis including ozonolysis enables structural assignment over a dynamic range of five orders of magnitude, even in instances of incomplete chromatographic separation. Thereby we expand the number of identified plasma fatty acids two-fold, including non-methylene interrupted fatty acids. Detection, without prior knowledge, allows discovery of non-canonical double bond positions. Changes in relative isomer abundances reflect underlying perturbations in lipid metabolism.

molecular biology↗

bioRxiv2021

Modified defence peptides from horseshoe crab target and kill bacteria inside host cells

Bacteria that occupy an intracellular niche can evade extracellular host immune responses and antimicrobial molecules. In addition to classic intracellular pathogens, other bacteria including uropathogenic Escherichia coli (UPEC) can adopt both extracellular and intracellular lifestyles. UPEC intracellular survival and replication complicates treatment, as many therapeutic molecules do not effectively reach all components of the infection cycle. In this study, we explored cell penetrating antimicrobial peptides from distinct structural classes as alternative molecules for targeting bacteria. We identified two {beta}-hairpin peptides from the horseshoe crab, tachyplesin I and polyphemusin I, with broad antimicrobial activity toward a panel of pathogenic and non-pathogenic bacteria in planktonic form. Peptide analogues [I11A]tachyplesin I and [I11S]tachyplesin I maintained activity toward bacteria, but were less toxic to mammalian cells than native tachyplesin I. This important increase in therapeutic window allowed treatment with higher concentrations of [I11A]tachyplesin I and [I11S]tachyplesin I, to significantly reduce intramacrophage survival of UPEC in an in vitro infection model. Mechanistic studies using bacterial cells, model membranes and cell membrane extracts, suggest that tachyplesin I and polyphemusin I peptides kill UPEC by selectively binding and disrupting bacterial cell membranes. Moreover, treatment of UPEC with sublethal peptide concentrations increased zinc toxicity and enhanced innate macrophage antimicrobial pathways. In summary, our combined data show that cell penetrating peptides are attractive alternatives to traditional small molecule antibiotics for treating UPEC infection, and that optimization of native peptide sequences can deliver effective antimicrobials for targeting bacteria in extracellular and intracellular environments.

microbiology↗