Project description:Induction of cell death represents a primary goal of most anti-cancer treatments. Despite the efficacy of such approaches, a small population of “persisters” develop evasion strategies to therapy-induced cell death. While previous studies have identified mechanisms of resistance to apoptosis, the mechanisms by which persisters dampen other forms of cell death, such as pyroptosis, remain to be elucidated. Pyroptosis is a form of inflammatory cell death that involves formation of membrane pores, ion gradient imbalance, water inflow and membrane rupture. Herein, we investigate mechanisms by which cancer persisters resist pyroptosis, survive, then proliferate in the presence of tyrosine kinase inhibitors (TKI). Lung, prostate and esophageal cancer persister cells remaining after treatments exhibited several hallmarks indicative of pyroptosis resistance. The inflammatory attributes of persisters included chronic activation of inflammasome, STING, and type I interferons. Comprehensive metabolomic characterization uncovered that TKI-induced pyroptotic persisters display high methionine consumption and excessive taurine production. Elevated methionine flux or exogenous taurine maintained plasma membrane integrity via osmolyte-mediated effects. Increased dependency on methionine flux decreased the level of one carbon metabolism intermediate S-(5'-adenosyl)-L-homocysteine, a determinant of cell methylation capacity. The consequent increase in methylation potential induced DNA hypermethylation of genes regulating metal ion balance and intrinsic immune response. This enabled thwarting TKI resistance by using the hypomethylating agent decitabine. In summary, the evolution of resistance to pyroptosis can occur via a stepwise process of physical acclimation and epigenetic changes without existing or recurrent mutations.
2022-12-02 | GSE219044 | GEO
Project description:Elevated methionine flux drives pyroptosis evasion in persister cancer cells
Project description:Bacterial persister cells are phenotypic variants of regular cells that are tolerant to antibiotics. High-persister (hip) mutants of Mycobacterium tuberculosis produce 10- to 1,000-fold more persister cells than the wild type strain when challenged with various antibiotics. Comparison of gene expression pattern of the hip mutants may provide clues as to the genetic mechanisms underlying persister formation. Transcriptome analysis will provide information on what differentiates M. tuberculosis hip strains from regular strains, which will be useful in the development of anti-persister therapy for persister cell eradication. Twelve independent M. tuberculosis hip mutants and the wild type strain were grown to stationary phase in duplicate. To avoid analyzing the drug effect, total RNA was extracted from the cultures prior to the addition of antibiotic for hybridization to Affymetrix microarrays. Data analysis was performed by comparing the hip mutants to the wild type control.
Project description:Acquired drug resistance prevents targeted cancer therapy from achieving stable and complete responses. Emerging evidence implicates a key role for nonmutational mechanisms including changes in cell state during early stages of acquired drug resistance. Targeting nonmutational resistance may therefore present a therapeutic opportunity to eliminate residual surviving tumor cells and impede relapse. A variety of cancer cell lines harbor quiescent, reversibly drug-tolerant âpersisterâ cells which survive cytotoxic drugs including targeted therapies and chemotherapies. These persister cells survive drug through nonmutational mechanisms which are poorly understood. Specifically targeting persister cells is a promising strategy to prevent tumor relapse. We sought to identify therapeutically exploitable vulnerabilities in persister cells using the HER2-amplified breast cancer line BT474 as an experimental model. Similar to other persister cell models, upon treatment with the HER2 inhibitor lapatinib (2uM concentration) for nine or more days, the majority of BT474 cells die, revealing a small population of quiescent surviving persister cells. Removal of lapatinib allows the persister cells to regrow and to re-acquire sensitivity to lapatinib. Subsequent lapatinib treatment re-derives persister cells. The reversibility of persister cell drug resistance indicates a nonmutational resistance mechanism. Here we provide RNAseq gene expression profiling data generated from parental BT474 cells compared to BT474 persister cells generated from nine days of treatment with 2 uM lapatinib. These data can be used to identify genes and pathways which are upregulated in persister cells, revealing potential therapeutic targets. 3 biological replicates of BT474 persister cells, two biological replicates of BT474 parental cells
Project description:Persisters are cells which evade stresses like antibiotics and which are characterized by reduced metabolism and a lack of genetic alterations required to achieve this state. We showed previously that MqsR and MqsA of Escherichia coli are a toxin-antitoxin pair that influence cell physiology (e.g., biofilm formation and motility) via RNase activity as well as through regulation of toxin CspD. Here, we show that deletion of the mqsRA locus decreases persister cell formation and, consistent with this result, overexpression of MqsR increases persister cell formation. Furthermore, toxins Hha, CspD, and HokA increase persister cell formation. In addition, by overproducing MqsR in a series of isogenic mutants, we show that Hha and CspD are necessary for persister cell formation via MqsR overexpression. Surprisingly, Hfq, a small RNA chaperone, decreases persistence. A whole-transcriptome study shows that Hfq induces transport-related genes (oppA, oppB, oppC, oppD, oppF, and dppA), outer membrane protein-related genes (ybfM and ybfN), toxins (hha), and proteases (clpX, clpP, and lon). Taken together, these results indicate that toxins CspD and Hha influence persister cell formation via MqsR and that Hfq plays an important role in the regulation of persister cell formation via regulation of transport or outer membrane proteins. Strains: E. coli BW25113 K-12 hfq deleted mutant vs. wild-type Medium: LB Culture: Planktonic cell grown OD=0.5, adjusted OD=1.0, and then exposed to 100 ug/mL ampicillin for 2 h.
Project description:Bacterial persister cells are phenotypic variants of regular cells that are tolerant to antibiotics. High-persister (hip) mutants of Mycobacterium tuberculosis produce 10- to 1,000-fold more persister cells than the wild type strain when challenged with various antibiotics. Comparison of gene expression pattern of the hip mutants may provide clues as to the genetic mechanisms underlying persister formation. Transcriptome analysis will provide information on what differentiates M. tuberculosis hip strains from regular strains, which will be useful in the development of anti-persister therapy for persister cell eradication.
Project description:Choline supplies methyl groups for regeneration of methionine and the methyl donor S-adenosylmethionine in the liver. Here we demonstrate that the catabolism of membrane phosphatidylcholine (PC) into water-soluble glycerophosphocholine (GPC) by the phospholipase/lysophospholipase PNPLA8-PNPLA7 axis enables endogenous choline stored in hepatic PC to be utilized in methyl metabolism. PNPLA7-deficient mice show marked decreases in hepatic GPC, choline, and several metabolites related to the methionine cycle, accompanied by various signs of methionine insufficiency including growth retardation, hypoglycemia, hypolipidemia, increased energy consumption, reduced adiposity, increased FGF21, and an altered epigenetic methylation landscape. Moreover, PNPLA8-deficient mice recapitulate most of these phenotypes. In contrast to wild-type mice fed a methionine/choline-deficient diet, both knockout strains display a decreased hepatic triglyceride likely via reductions of lipogenesis and GPC-derived glycerol flux. Collectively, our findings highlight the biological importance of phospholipid catabolism driven by PNPLA8/PNPLA7 in methyl group flux and triglyceride synthesis in the liver.
Project description:Choline supplies methyl groups for regeneration of methionine and the methyl donor S-adenosylmethionine in the liver. Here we demonstrate that the catabolism of membrane phosphatidylcholine (PC) into water-soluble glycerophosphocholine (GPC) by the phospholipase/lysophospholipase PNPLA8-PNPLA7 axis enables endogenous choline stored in hepatic PC to be utilized in methyl metabolism. PNPLA7-deficient mice show marked decreases in hepatic GPC, choline, and several metabolites related to the methionine cycle, accompanied by various signs of methionine insufficiency including growth retardation, hypoglycemia, hypolipidemia, increased energy consumption, reduced adiposity, increased FGF21, and an altered epigenetic methylation landscape. Moreover, PNPLA8-deficient mice recapitulate most of these phenotypes. In contrast to wild-type mice fed a methionine/choline-deficient diet, both knockout strains display a decreased hepatic triglyceride likely via reductions of lipogenesis and GPC-derived glycerol flux. Collectively, our findings highlight the biological importance of phospholipid catabolism driven by PNPLA8/PNPLA7 in methyl group flux and triglyceride synthesis in the liver.
Project description:Choline supplies methyl groups for regeneration of methionine and the methyl donor S-adenosylmethionine in the liver. Here we demonstrate that the catabolism of membrane phosphatidylcholine (PC) into water-soluble glycerophosphocholine (GPC) by the phospholipase/lysophospholipase PNPLA8-PNPLA7 axis enables endogenous choline stored in hepatic PC to be utilized in methyl metabolism. PNPLA7-deficient mice show marked decreases in hepatic GPC, choline, and several metabolites related to the methionine cycle, accompanied by various signs of methionine insufficiency including growth retardation, hypoglycemia, hypolipidemia, increased energy consumption, reduced adiposity, increased FGF21, and an altered epigenetic methylation landscape. Moreover, PNPLA8-deficient mice recapitulate most of these phenotypes. In contrast to wild-type mice fed a methionine/choline-deficient diet, both knockout strains display a decreased hepatic triglyceride likely via reductions of lipogenesis and GPC-derived glycerol flux. Collectively, our findings highlight the biological importance of phospholipid catabolism driven by PNPLA8/PNPLA7 in methyl group flux and triglyceride synthesis in the liver.
Project description:Pyroptosis is a recently discovered form of lytic cell death that is characterized by cell swelling and formation of pores and large bubbles on the plasma membrane. We find radiation could induce pyroptosis in human colorectal cancer HCT116 cells, and irradiation induces pyroptosis in mouse normal intestine MODEK cells only after 36 hours and over 8.0 Gy. In view of the significant pyroptosis effect of MODE-K cells, we selected 4Gy and 12Gy, 24h and 48h for experiments. After ONT full-length transcriptome sequencing, the cell pyroptosis model can screen out the differential genes related to cell pyroptosis, which is helpful to further explore the mechanism of pyroptosis of MODE-K cells.