ABSTRACT
Otto Warburg described tumour cells as displaying enhanced aerobic glycolysis whilst maintaining defective oxidative phosphorylation (OXPHOS) for energy production almost 100 years ago [1, 2]. Since then, the 'Warburg effect' has been widely accepted as a key feature of rapidly proliferating cancer cells [3-5]. What is not clear is how early "Warburg metabolism" initiates in cancer and whether changes in energy metabolism might influence tumour progression ab initio. We set out to investigate energy metabolism in the HRASG12V driven preneoplastic cell (PNC) at inception, in a zebrafish skin PNC model. We find that, within 24 h of HRASG12V induction, PNCs upregulate glycolysis and blocking glycolysis reduces PNC proliferation, whilst increasing available glucose enhances PNC proliferation and reduces apoptosis. Impaired OXPHOS accompanies enhanced glycolysis in PNCs, and a mild complex I inhibitor, metformin, selectively suppresses expansion of PNCs. Enhanced mitochondrial fragmentation might be underlining impaired OXPHOS and blocking mitochondrial fragmentation triggers PNC apoptosis. Our data indicate that altered energy metabolism is one of the earliest events upon oncogene activation in somatic cells, which allows a targeted and effective PNC elimination.
ABSTRACT
Photoactivatable molecules enable ablation of malignant cells under the control of light, yet current agents can be ineffective at early stages of disease when target cells are similar to healthy surrounding tissues. In this work, we describe a chemical platform based on amino-substituted benzoselenadiazoles to build photoactivatable probes that mimic native metabolites as indicators of disease onset and progression. Through a series of synthetic derivatives, we have identified the key chemical groups in the benzoselenadiazole scaffold responsible for its photodynamic activity, and subsequently designed photosensitive metabolic warheads to target cells associated with various diseases, including bacterial infections and cancer. We demonstrate that versatile benzoselenadiazole metabolites can selectively kill pathogenic cells - but not healthy cells - with high precision after exposure to non-toxic visible light, reducing any potential side effects in vivo. This chemical platform provides powerful tools to exploit cellular metabolic signatures for safer therapeutic and surgical approaches.
Subject(s)
Bacterial Infections/drug therapy , Fluorescent Dyes/administration & dosage , Glioblastoma/drug therapy , Organoselenium Compounds/administration & dosage , Photochemotherapy/methods , Animals , Coculture Techniques , Fluorescent Dyes/adverse effects , Fluorescent Dyes/chemistry , Fluorescent Dyes/radiation effects , Glioblastoma/pathology , Humans , Intravital Microscopy , Light , Microbial Sensitivity Tests , Microscopy, Confocal , Microscopy, Fluorescence , Organoselenium Compounds/adverse effects , Organoselenium Compounds/chemistry , Organoselenium Compounds/radiation effects , Spheroids, Cellular , Xenograft Model Antitumor Assays , ZebrafishABSTRACT
Drosophila provides a powerful model in which to study inflammation in vivo, and previous studies have revealed many of the key signaling events critical for recruitment of immune cells to tissue damage. In the fly, wounding stimulates the rapid production of hydrogen peroxide (H2O2).1,2 This then acts as an activation signal by triggering a signaling pathway within responding macrophages by directly activating the Src family kinase (SFK) Src42A,3 which in turn phosphorylates the damage receptor Draper. Activated Draper then guides macrophages to the wound through the detection of an as-yet unidentified chemoattractant.3-5 Similar H2O2-activated signaling pathways are also critical for leukocyte recruitment following wounding in larval zebrafish,6-9 where H2O2 activates the SFK Lyn to drive neutrophil chemotaxis. In this study, we combine proteomics, live imaging, and genetics in the fly to identify a novel regulator of inflammation in vivo; the PTP-type phosphatase Pez. Pez is expressed in macrophages and is critical for their efficient migration to wounds. Pez functions within activated macrophages downstream of damage-induced H2O2 and operates, via its band 4.1 ezrin, radixin, and moesin (FERM) domain, together with Src42A and Draper to ensure effective inflammatory cell recruitment to wounds. We show that this key role is conserved in vertebrates, because "crispant" zebrafish larvae of the Draper ortholog (MEGF10) or the Pez ortholog (PTPN21) exhibit a failure in leukocyte recruitment to wounds. This study demonstrates evolutionary conservation of inflammatory signaling and identifies MEGF10 and PTPN21 as potential therapeutic targets for the treatment of inflammatory disorders.
