Dataset Information

The Function of Ectopic ATP Synthase in Extracellular Vesicles.

ABSTRACT: Ectopic adenosine triphosphate synthase (eATP synthase) was found on the cell surface to generate extracellular ATP in various cancer cells. Recently using proteomics approach, several reports identified ATP synthase in extracellular vesicles (EVs) which are important in cell-cell communications. However, the functions of ATP synthase in EVs are still unclear. Here we increased the expression of eATP synthase on the plasma membrane of lung cancer A549 cells via 0.1% FBS starvation and collected EVs including microvesicles and exosomes from the culture medium using serial centrifugation. Both of them were assuredly isolated and confirmed by transmission electron microscopy, nano tracking analysis, and specific EV markers. We also used western blot to demonstrate the presence of ATP synthase in EVs. Besides, dot blot experiment revealed that the F1 portion faced towards extracellular space using anti-ATP beta subunit antibody. Under starvation, the expression of eATP synthase was enhanced on cell surface and exosomes as well as increased EV secretion. To further investigate the functions, we first elucidated whether eATP synthase on EV membrane produced ATP by ATP luciferase analysis. Our data showed that there was no significant ATP production. Moreover, we performed proteomic analysis using dimethyl labeling and LC-MS/MS to compare the difference between EVs released by A549 control and starvation. We identified a total of 1504 and 869 proteins in microvesicles and exosomes, respectively. Using 1.5- and 0.67-fold change as the thresholds, there were 171 and 46 differential expressed proteins in microvesicles and exosomes, respectively. Seven ATP synthase subunits in microvesicles and five in exosomes were identified. The proteomic data were further analyzed using gene set enrichment analysis (GSEA) within the C2 (curated gene sets) subclasses and setting 0.25 as FDR cutoff to find out biological functions related to eATP synthase. Among these up-regulated terms, metabolism, cell cycle and apoptosis were enriched, which indicating that starvation influences cell behavior. Additionally, the immune response is upregulated strikingly in exosomes within C2 gene set. One of these immune response pathways, MHC-1 antigen presentation, was previously proved to interact with eATP synthase which could be recognized by several immune cells.

INSTRUMENT(S): LTQ Orbitrap Elite

ORGANISM(S): Homo Sapiens (human)

TISSUE(S): Epithelial Cell, Cell Culture

SUBMITTER: Chang Nai-Wen

LAB HEAD: Hsueh-Fen Juan

PROVIDER: PXD014995 | Pride | 2023-05-22

REPOSITORIES: Pride

ACCESS DATA

Similar Datasets

Project description:Neuroblastoma (NB) is an embryonal tumor with various clinical presentations and behaviors. Several genomic alterations has been well-studied in NB, among which genomic amplification of MYCN oncogene, is a strong prognostic biomarker with worsens outcome. Long noncoding RNAs (lncRNAs), constitute major proportion of the cellular transcripts with no coding capacity. One of their function is to guide transcription factors to the target genes and facilitate gene expression. However, relative contribution of lncRNA and MYCN to the advanced NB has remained unclear. Herein, by applying a network-based integrative analysis on MYCN amplified and MYCN nonamplified lncRNA expression profile from both RNA-seq and microarray platform, we identified lncRNA, SNHG1 to be differentially expressed and strongly correlated with MYCN in MYCN-amplified NB. The expression of SNHG1 was validated by RT-qPCR in NB cell lines. Survival analysis revealed that higher expression of SNHG1 significantly associates with poor patient survival. Moreover, knockdown of MYCN in MYCN-amplified NB cell lines inhibited SNHG1 expression. Furthermore, to unravel the role of SNHG1 in NB, we extracted SNHG1-interacting proteins by RNA-protein pull down assay coupled with doi:10.6342/NTU201701980 ! ! VI liquid chromatography-tandem mass spectrometry (LC-MS/MS). We identified 27 SNHG1-interacting proteins in common from three NB cell lines. However, only three SNHG1-interacting proteins, MATR3, YBX1 and HHRNPL have binding site detected by DeepBind motif analysis. Western blot confirms interaction of MATR3 with SNHG1. Additionally, we further validated the direct interaction between MATR3 and SNHG1 by RNA-immunoprecipation (IP). MATR3 is known to be involved in RNA transport and stabilization. Therefore, we proposed that MATR3 after interacting with SNHG1 might help in SNHG1 transcription and stabilization. In conclusion, our study unveils that SNHG1 could be a prognostic marker for high-risk NB and possibly stabilized by MATR3. Our results might provide future directions for the development of therapeutic strategies against high-risk NB.

Project description:Adenosine triphosphate (ATP) synthase is located on the inner membrane of mitochondria which generate ATP for various cellular processes. Our previous studies showed that ATP synthases existed on plasma membrane of several types of cancer cells, which was defined as ectopic ATP synthase. However, the trafficking pathway of ectopic ATP synthase is still unclear. To investigate how ATP synthase subunits are involved in the trafficking process, we performed shot-gun proteomic analysis to reveal the plasma membrane proteins of A549 lung cancer cells and identified four subunits of ATP synthases, ATP5A1, ATP5B, ATP5H, and MT-ATP6. With the results of gene set enrichment analysis, we inferred that ectopic ATP synthase subunits are assembled as complex consistently and then translocated to cell surface through the trafficking of mitochondria. On the other hand, microtubules are involved in many intracellular transport. During protein trafficking, mitochondria and vesicles are transported to their final destination along microtubules by motor proteins such as kinesins and dyneins. To explore the function of microtubules in the trafficking of ectopic ATP synthase, we treated MCF-7 breast and A549 lung cancer cells with nocodazole, a microtubule depolymerization agent, and found that the expression level of ectopic ATP synthase decreased using both immunocytochemistry and flow cytometry. Besides, since kinesin family member 5B (KIF5B) is an important motor proteins involved in the transport of mitochondria, we further performed the immunoprecipitation of KIF5B followed by liquid chromatography−tandem mass spectrometry (LC−MS/MS). The result revealed that one of the mitochondrial outer membrane proteins, dynamin-1 like proteins (Drp1), was able to associate to KIF5B. From our recent research results and other reports show that Drp1 is a mediator of mitochondrial dynamic through regulation of mitochondrial fission. Taken together, our findings suggested that Drp1-KIF5B complex-mediated mitochondrial trafficking along microtubules may play a critical role in the transport of ectopic ATP synthase

Project description:Lung cancer is one of the most common and fatal cancer worldwide. There are two major types of lung cancer, non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC). Recently, gefitinib, a small molecule, which target tyrosine kinase, has been regarded as the first-line treatment in NSCLC patients. However, several patients have been observed tumor recurrence and eventually developed progressive outcomes after target therapy. Thus, an effective therapeutic approach need to be explored. Here, we found that ectopically expressed ATP synthase on plasma membrane exhibited gefitinib-resistance properties in lung cancer cell lines. Furthermore, we unraveled that citreoviridin, an ectopic ATP synthase inhibitor, suppressed the abilities of both proliferation and colony formation in lung cancer cell lines. To elucidate the comprehensive mechanism regulated by citreoviridin, we performed microarray analysis. The results indicated that not only mRNAs but also long non-coding RNAs (lncRNAs) are involved in citreoviridin-treated cell death. One of the well-known lncRNAs, growth arrest-specific transcript (GAS5), was robustly upregulated after citreoviridin treatment. In order to investigate the upstream modulator of GAS5, we utilized chromatin immunoprecipitation (ChIP) assay and revealed that E2F transcription factor 1 (E2F1) could bind to the promoter of GAS5. Consistently, both microarray and qPCR data showed the expression level of E2F1 was negatively correlated to GAS5 after citreoviridin treatment. The evidence suggests that E2F1 might be a potential repressor of GAS5. Furthermore, combining microarray and Gene Set Enrichment Analysis (GSEA) analysis as well as qPCR demonstrated that p53 pathway was activated. To further realize the GAS5-p53 regulating network, RNA-protein pull-down assay followed by LC-MS/MS will be utilized to dissect the GAS5-interacting proteomic profiling.From the results, we identified 107 GAS5-interacting proteins in common from A549 and H1975 cell lines. Our proteomics experiments identified topoisomerase 2-alpha (TOP2A) as the key protein involved in the citreoviridin-regulated gefitinib-resistance pathway, therefore, we picked out TOP2A for further study. Additionally, we further validated the interaction between TOP2A and GAS5 by western blot and RNA immunoprecipitation (RIP). Taken together, this study suggests targeting E2F1/GAS5/p53 axis is a potential therapeutic strategy for gefitinib-resistant lung cancer.

Dataset Information

The Function of Ectopic ATP Synthase in Extracellular Vesicles.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure