Project description:MYC has been named the quintessential oncogene and is deregulated in the majority of human cancers. Still, finding c-MYC inhibitors for therapeutic use has been problematic and MYC itself has long been viewed as “undruggable”. Here we present a novel strategy for achieving c-MYC inhibition, involving specific bacterial effector molecules. We made the surprising observation that uropathogenic E. coli activate c-MYC degradation and attenuate MYC expression in host cells and tissues. We further identified effector molecules responsible for this effect. The bacterial Lon protease is shown to rapidly degrade c-MYC and therapeutic efficacy is demonstrated in bladder and colon cancer models. Long-term protection, defined by delayed tumor progression, increased survival and low toxicity further supports the therapeutic potential of Lon. These results suggest that bacteria have evolved strategies to control c-MYC tissue levels in the host, which can be exploited to target c-MYC therapeutically in different cancers.
Project description:Lon protease is known to regulate various transcriptional regulators in other bacterial organisms. To understand whether lon protease is involved in transcriptional changes in Vibrio cholerae, wholel-genome level transcriptional profiling was performed using custom microarrays. Transcriptomes of lonA mutant and wild-type strains were compared in this study.
Project description:Lon protease is known to regulate various transcriptional regulators in other bacterial organisms. To understand whether lon protease is involved in transcriptional changes in Vibrio cholerae, wholel-genome level transcriptional profiling was performed using custom microarrays. Transcriptomes of lonA mutant and wild-type strains were compared in this study. Three biological replicates of wild-type and lonA mutant strains were used for this study. Reference RNA sample was harvested from wild-type strain.
Project description:Purpose: Next-generation sequencing (NGS) has revolutionized systems-based analysis of cellular pathways. The goals of this study are to compare NGS-derived transcriptome profiling (RNA-seq) and transposon insertion mutagenesis (Tnseq) libraries of Lon deletions compared to wt Caulobacter crescentus. Methods: See Methods section of The Lon protease links nucleotide metabolism with proteotoxic stress for information regarding methods or contact lead correspondence. Briefly, Samples for RNAseq were extracted from wt and lon deletion strains grown to mid exponential phase. Methods: See Methods section of The Lon protease links nucleotide metabolism with proteotoxic stress for information regarding methods or contact lead correspondence. Briefly, Samples for Tnseq were generated by Eztn5 transposon mutagenesis. Conclusions: Our study represents the first detailed analysis of lon deletion comparison to wt caulobacter transcriptomes, with biologic replicates, generated by RNA-seq technology.
Project description:MYC has been named the quintessential oncogene and is deregulated in the majority of human cancers. Still, finding c-MYC inhibitors for therapeutic use has been problematic and MYC itself has long been viewed as “undruggable”. Here we present a novel strategy for achieving c-MYC inhibition, involving specific bacterial effector molecules. We made the surprising observation that uropathogenic E. coli activate c-MYC degradation and attenuate MYC expression in host cells and tissues. We further identified effector molecules responsible for this effect. The bacterial Lon protease is shown to rapidly degrade c-MYC and therapeutic efficacy is demonstrated in bladder and colon cancer models. Long-term protection, defined by delayed tumor progression, increased survival and low toxicity further supports the therapeutic potential of Lon. These results suggest that bacteria have evolved strategies to control c-MYC tissue levels in the host, which can be exploited to target c-MYC therapeutically in different cancers.
Project description:In Escherichia coli, Lon is an ATP-dependent protease which degrades misfolded proteins and certain rapidly-degraded regulatory proteins. Given that oxidatively damaged proteins are generally degraded rather than repaired, we anticipated that Lon deficient cells would exhibit decreased viability during aerobic, but not anaerobic, carbon starvation. We found that the opposite actually occurs. Wild-type and Lon deficient cells survived equally well under aerobic conditions, but Lon deficient cells died more rapidly than the wild-type under anaerobiosis. Microarray analysis revealed that genes of the Clp family of ATP-dependent proteases were induced during aerobic growth but not during anaerobic growth. Thus, Clp may compensate for loss of Lon when cells are in an oxygen containing atmosphere. Under anaerobic carbon starvation conditions, Lon must be active to support survival. Keywords: Other
Project description:With this analysis we aim to identify proteins that are substrates of LarA-activated Lon protease in Caulobacter crescentus. We will compare samples of wild type cells either harboring an empty vector (vector control, VC) or overexpressing 3xFLAG-tagged LarA (F-LarA). Based on our previous data we hypothesize that proteins affected by LarA-overexpression which results in Lon protease activation will decrease in levels compared to the vector control sample. The aim of this analysis is the identification of the interactome of the Lon protease in Caulobacter crescentus. It is a follow-up analysis of a project in which we were looking for novel substrates of the Lon protease in Caulobacter crescentus. To narrow down the list of potential substrates we obtained through the first analysis, we have purified the protease (Lon WT) as well an inactive TRAP mutant and interacting proteins using a Twin-Strep-tag (Iba lifesciences). As a control, a cell lysate without Strep-tag containing protein was included in the purification set-up. The aim is to identify the proteins that specifically interact with the Lon protease by mass spectrometry.
Project description:Lon protease plays vital roles in many biological processes in Pseudomonas syringae, including type III secretion systems (T3SS), transcription regulation, protein synthesis and energy metabolism. Lon also functions as a transcriptional regulator in other bacterial species (e.g., Escherichia coli and Brevibacillus thermoruber). Therefore, we hypothesise that Lon has dual functions in P. syringae. To reveal the molecular mechanisms of Lon as a transcriptional regulator and protease under different environmental conditions, we used a combination of transcriptome sequencing (RNA-seq), chromatin immunoprecipitation sequencing (ChIP-seq) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) to identify the genes or proteins regulated by Lon. As a transcriptional regulator, Lon bound to the promoter regions of PSPPH_4788, gacA, fur, gntR, clpS, lon and glyA and consequently regulated 1-dodecanol oxidation activity, motility, pyoverdine production, gluconokinase activity, N-end rule pathway, lon expression and serine hydroxymethyltransferase (SHMT) activity in King’s B medium (KB). In minimal medium (MM), Lon regulated SHMT activity and lon expression by binding to the promoter regions of glyA and lon, respectively. As a protease, Lon regulated the T3SS and metabolic pathways (e.g., amino acid metabolism). In MM, Lon regulated the polysaccharide metabolic process by controlling PSPPH_0514, AlgA, CysD and PSPPH_4991. Taken together, these data demonstrate that Lon acts as a transcriptional regulator or protease in different environments and tunes its virulence and metabolic functions accordingly.