PlncRNA-encoded pep-AP attenuates the pentose phosphate pathway and sensitizes colorectal cancer cells to Oxaliplatin
Ontology highlight
ABSTRACT:
SUBMITTER: Dr. Xinyi Wang
PROVIDER: S-SCDT-EMBOR-2021-53140-T | biostudies-other |
REPOSITORIES: biostudies-other
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Project description:Oxaliplatin (L-OHP) is a standard treatment for colorectal cancer (CRC), but chemoresistance is a considerable challenge. L-OHP shows dose-dependent toxicity, and potential approaches that sensitize cancer cells to L-OHP could reduce the dosage. With the development of translatomics, it was found that some lncRNAs encode short peptides. Here, we use ribosome footprint profiling combined with lncRNA-Seq to screen 12 lncRNAs with coding potential, of which lnc-AP encodes the short peptide pep-AP, for their role in L-OHP resistance. Co-IP and LC-MS/MS data show that the TALDO1 protein interacts with pep-AP and that pep-AP suppresses the expression of TALDO1. The pep-AP/TALDO1 pathway attenuates the pentose phosphate pathway (PPP), reducing NADPH/NADP+ and glutathione (GSH) levels and causing ROS accumulation and apoptosis, which sensitizes CRC cells to L-OHP in vitro and in vivo. pep-AP thus might become a potential anticancer peptide for future treatments of L-OHP-resistant CRC.
| S-EPMC8728603 | biostudies-literature
Project description:BackgroundDrug resistance is one of the major concerns in the treatment of hepatocellular carcinoma (HCC). The aim of the present study was to determine whether aberrant high expression of the inhibitor of differentiation 1(ID1) confers oxaliplatin-resistance to HCC by activating the pentose phosphate pathway (PPP).MethodsAberrant high expression of ID1 was detected in two oxaliplatin-resistant cell lines MHCC97H-OXA(97H-OXA) and Hep3B-OXA(3B-OXA). The lentiviral shRNA or control shRNA was introduced into the two oxaliplatin-resistant cell lines. The effects of ID1 on cell proliferation, apoptosis and chemoresistance were evaluated in vitro and vivo. The molecular signaling mechanism underlying the induction of HCC proliferation and oxaliplatin resistance by ID1 was explored. The prognostic value of ID1/G6PD signaling in HCC patients was assessed using the Cancer Genome Atlas (TCGA) database.ResultsID1 was upregulated in oxaliplaitin-resistant HCC cells and promoted HCC cell proliferation and oxaliplatin resistance. Silencing ID1 expression in oxaliplaitin-resistant HCC cell lines inhibited cell proliferation and sensitized oxaliplaitin-resistant cells to death. ID1 knockdown significantly decreased the expression of glucose-6-phosphate dehydrogenase (G6PD), a key enzyme of the PPP. Silencing ID1 expression blocked the activation of G6PD, decreased the production of PPP NADPH, and augmented reactive oxygen and species (ROS), thus inducing cell apoptosis. Study of the molecular mechanism showed that ID1 induced G6PD promoter transcription and activated PPP through Wnt/β-catenin/c-MYC signaling. In addition, ID1/G6PD signaling predicted unfavorable prognosis of HCC patients on the basis of TCGA.ConclusionsOur study provided the first evidence that ID1 conferred oxaliplatin resistance in HCC by activating the PPP. This newly defined pathway may have important implications in the research and development of new more effective anti-cancer drugs.
| S-EPMC5701377 | biostudies-literature
Project description:Recurrent tumors originate from cancer stem cells (CSCs) that survive conventional treatments. CSCs consist of heterogeneous subpopulations that display distinct sensitivity to anticancer drugs. Such a heterogeneity presents a significant challenge in preventing tumor recurrence. In the current study, we observed that quiescent CUB-domain-containing protein 1 (CDCP1)+ CSCs are enriched after chemotherapy in mutant Kirsten rat sarcoma viral oncogene homolog (Kras) colorectal carcinomas (CRCs) and serve as a reservoir for recurrence. Mechanistically, glucose catabolism in CDCP1+ CSCs is routed to the oxidative pentose phosphate pathway (PPP); multiple cycling of carbon backbones in the oxidative PPP potentially maximizes NADPH reduction to counteract chemotherapy-induced reactive oxygen species (ROS) formation, thereby allowing CDCP1+ CSCs to survive chemotherapeutic attack. This is dependent on silent mating type information regulation 2 homolog 5 (Sirt5)-mediated inhibition of the glycolytic enzyme triosephosphate isomerase (TPI) through demalonylation of Lys56. Blocking demalonylation of TPI at Lys56 increases chemosensitivity of CDCP1+ CSCSs and delays recurrence of mutant Kras CRCs in vivo. These findings pinpoint a new therapeutic approach for combating mutant Kras CRCs.
| S-EPMC6736310 | biostudies-literature
Project description:Oxaliplatin-based therapeutics is a widely used treatment approach for hepatocellular carcinoma (HCC) patients; however, drug resistance poses a significant clinical challenge. Epigenetic modifications have been implicated in the development of drug resistance. In our study, employing siRNA library screening, we identified that silencing the m6A writer METTL3 significantly enhanced the sensitivity to oxaliplatin in both in vivo and in vitro HCC models. Further investigations through combined RNA-seq and non-targeted metabolomics analysis revealed that silencing METTL3 impeded the pentose phosphate pathway (PPP), leading to a reduction in NADPH and nucleotide precursors. This disruption induced DNA damage, decreased DNA synthesis, and ultimately resulted in cell cycle arrest. Mechanistically, METTL3 was found to modify E3 ligase TRIM21 near the 3'UTR with N6-methyladenosine, leading to reduced RNA stability upon recognition by YTHDF2. TRIM21, in turn, facilitated the degradation of the rate-limiting enzyme of PPP, G6PD, through the ubiquitination-proteasome pathway. Importantly, high expression of METTL3 was significantly associated with adverse prognosis and oxaliplatin resistance in HCC patients. Notably, treatment with the specific METTL3 inhibitor, STM2457, significantly improved the efficacy of oxaliplatin. These findings underscore the critical role of the METTL3/TRIM21/G6PD axis in driving oxaliplatin resistance and present a promising strategy to overcome chemoresistance in HCC.
2024-08-23 | GSE241802 | GEO
Project description:Histone methylation is a context-dependent modification that regulates gene expression, and the trimethylation of histone H3 lysine 27 (H3K27me3) usually induces gene silencing. Overcoming colorectal cancer (CRC) chemoresistance is currently a huge challenge, but the relationship between H3K27me3 modification and chemoresistance remains largely unclear. Here, we found that H3K27me3 levels positively correlated with the metastasis-free survival of CRC patients and a low H3K27me3 level predicted a poor outcome upon chemotherapeutic drug treatment. Oxaliplatin stimulation significantly induced the expression of H3K27 lysine demethylase 6A/6B (KDM6A/6B), thus decreasing the level of H3K27me3 in CRC cells. Elevation of H3K27me3 level through KDM6A/6B depletion or GSK-J4 (a KDM6A/6B inhibitor) treatment significantly enhanced oxaliplatin-induced apoptosis. Conversely, when inhibiting the expression of H3K27me3 by EPZ-6438, an inhibitor of the histone methyltransferase EZH2, the proportion of apoptotic cells remarkably decreased. In addition, the combination of GSK-J4 and oxaliplatin significantly inhibited tumor growth in an oxaliplatin-resistant patient-derived xenograft model. Importantly, we revealed that oxaliplatin treatment dramatically induced NOTCH2 expression, which was caused by downregulation of H3K27me3 level on the NOTCH2 transcription initiation site. Thus, the activated NOTCH signaling promoted the expression of stemness-related genes, which resulted in oxaliplatin resistance. Furthermore, oxaliplatin-induced NOTCH signaling could be interrupted by GSK-J4 treatment. Collectively, our findings suggest that elevating H3K27me3 level can improve drug sensitivity in CRC patients.
| S-EPMC7109602 | biostudies-literature
Project description:Gain-of-function mutations in isocitrate dehydrogenase 1 (IDH1) occur in multiple types of human cancer. Here, we show that these mutations significantly disrupt NADPH homeostasis by consuming NADPH for 2-hydroxyglutarate (2-HG) synthesis. Cells respond to 2-HG synthesis, but not exogenous administration of 2-HG, by increasing pentose phosphate pathway (PPP) flux. We show that 2-HG production competes with reductive biosynthesis and the buffering of oxidative stress, processes that also require NADPH. IDH1 mutants have a decreased capacity to synthesize palmitate and an increased sensitivity to oxidative stress. Our results demonstrate that, even when NADPH is limiting, IDH1 mutants continue to synthesize 2-HG at the expense of other NADPH-requiring pathways that are essential for cell viability. Thus, rather than attempting to decrease 2-HG synthesis in the clinic, the consumption of NADPH by mutant IDH1 may be exploited as a metabolic weakness that sensitizes tumor cells to ionizing radiation, a commonly used anti-cancer therapy.
| S-EPMC6053654 | biostudies-literature
Project description:Due to its role in maintaining the proper functioning of the cell, the pentose phosphate pathway (PPP) is one of the most important metabolic pathways. It is responsible for regulating the concentration of simple sugars and provides precursors for the synthesis of amino acids and nucleotides. In addition, it plays a critical role in maintaining an adequate level of NADPH, which is necessary for the cell to fight oxidative stress. These reasons prompted the authors to develop a computational model, based on queueing theory, capable of simulating changes in PPP metabolites' concentrations. The model has been validated with empirical data from tumor cells. The obtained results prove the stability and accuracy of the model. By applying queueing theory, this model can be further expanded to include successive metabolic pathways. The use of the model may accelerate research on new drugs, reduce drug costs, and reduce the reliance on laboratory animals necessary for this type of research on which new methods are tested.
| S-EPMC8930976 | biostudies-literature
Project description:BackgroundPatients with colorectal cancer (CRC) with liver metastasis or drug resistance have a poor prognosis. Previous research has demonstrated that PPP2R1B inactivation results in the development of CRC. However, the role of PPP2R1B in CRC metastasis and drug resistance is unclear.MethodsVenny 2.1 was used to determine the intersection between survival-related differentially expressed genes (DEGs) and liver metastasis-related DEGs according to RNA-seq data from The Cancer Genome Atlas (TCGA) and the GEO database (GSE179979). LC‒MS/MS and coimmunoprecipitation were performed to predict and verify the substrate protein of PPP2R1B. Gene Set Variation Analysis (GSVA) was subsequently utilized to assess pathway enrichment levels. The predictive performance of PPP2R1B was assessed by regression analysis, Kaplan-Meier (KM) survival analysis and drug sensitivity analysis. Immunohistochemistry (IHC), qRT-PCR and western blotting were performed to measure the expression levels of related mRNAs or proteins. Biological features were evaluated by wound healing, cell migration and invasion assays and CCK-8 assays. A mouse spleen infection liver metastasis model was generated to confirm the role of PPP2R1B in the progression of liver metastasis in vivo.ResultsAccording to bioinformatics analysis, PPP2R1B is significantly associated with liver metastasis and survival in CRC patients, and these findings were further verified via immunohistochemistry (IHC), qPCR and Western blotting. Pathway enrichment and LC‒MS/MS analysis revealed that PPP2R1B is negatively associated with the MAPK/ERK signalling pathway. Additionally, PD98059, a MAPK/ERK pathway inhibitor, inhibited EMT in vitro by reversing the changes in key proteins involved in EMT signalling (ZEB1, E-cadherin and Snail) and ERK/MAPK signalling (p-ERK) mediated by PPP2R1B. Oxaliplatin sensitivity prediction and validation revealed that PPP2R1B silencing decreased Oxaliplatin chemosensitivity, and these effects were reversed by PD98059 treatment. Moreover, PPP2R1B was coimmunoprecipitated with p-ERK in vitro. A negative correlation between PPP2R1B and p-ERK expression was also observed in clinical CRC samples, and the low PPP2R1B/high p-ERK coexpression pattern indicated a poor prognosis in CRC patients. In vivo, PPP2R1B silencing significantly promoted liver metastasis.ConclusionsThis study revealed that PPP2R1B induces dephosphorylation of the p-ERK protein, inhibits liver metastasis and increases Oxaliplatin sensitivity in CRC patients and could be a potential candidate for therapeutic application in CRC.
| S-EPMC10908207 | biostudies-literature
Project description:BackgroundThe pentose phosphate pathway (PPP) is an important mechanism by which tumour cells resist stressful environments and maintain malignant proliferation. However, the mechanism by which the PPP regulates these processes in colorectal cancer (CRC) remains elusive.MethodsClosely related PPP genes were obtained from the TCGA and GEO databases. The effect of ATP13A2 on CRC cell proliferation was evaluated by performing in vitro assays. The connection between the PPP and ATP13A2 was explored by assessing proliferation and antioxidative stress. The molecular mechanism by which ATP13A2 regulates the PPP was investigated using chromatin immunoprecipitation and dual luciferase experiments. The clinical therapeutic potential of ATP13A2 was explored using patient-derived xenograft (PDX), patient-derived organoid (PDO) and AOM/DSS models.FindingsWe identified ATP13A2 as a novel PPP-related gene. ATP13A2 deficiency inhibited CRC growth and PPP activity, as manifested by a decrease in the levels of PPP products and an increase in reactive oxygen species levels, whereas ATP13A2 overexpression induced the opposite effect. Mechanistically, ATP13A2 regulated the PPP mainly by affecting phosphogluconate dehydrogenase (PGD) mRNA expression. Subsequent studies showed that ATP13A2 overexpression promoted TFEB nuclear localization by inhibiting the phosphorylation of TFEB, thereby enhancing the transcription of PGD and ultimately affecting the activity of the PPP. Finally, ATP13A2 knockdown inhibited CRC growth in PDO and PDX models. ATP13A2- /- mice had a lower CRC growth capacity than ATP13A2+/+ in the AOM/DSS model.Our findings revealed that ATP13A2 overexpression-driven dephosphorylation of TFEB promotes PPP activation by increasing PGD transcription, suggesting that ATP13A2 may serve as a potential target for CRC therapy.
| S-EPMC10220388 | biostudies-literature
Project description:A fundamental step in regeneration is rapid growth to replace lost tissue. Cells must generate sufficient lipids, nucleotides, and proteins to fuel rapid cell division. To define metabolic pathways underlying regenerative growth, we undertake a multimodal investigation of metabolic reprogramming in Xenopus tropicalis appendage regeneration. Regenerating tissues have increased glucose uptake; however, inhibition of glycolysis does not decrease regeneration. Instead, glucose is funneled to the pentose phosphate pathway (PPP), which is essential for full tail regeneration. Liquid chromatography-mass spectrometry (LC-MS) metabolite profiling reveals increased nucleotide and nicotinamide intermediates required for cell division. Using single-cell RNA sequencing (scRNA-seq), we find that highly proliferative cells have increased transcription of PPP enzymes and not glycolytic enzymes. Further, PPP inhibition results in decreased cell division specifically in regenerating tissue. Our results inform a model wherein regenerating tissues direct glucose toward the PPP, yielding nucleotide precursors to drive regenerative cell proliferation.
| S-EPMC10569227 | biostudies-literature