Project description:Non-small cell lung cancer is the leading cause of cancer death worldwide. Gefitinib, epidermal growth factor receptor tyrosine kinase inhibitor, is the first-line treatment of NSCLC, however, many patients eventually become resistant and experience progressive disease. Therefore, development of efficient therapeutic agents to overcome resistance is urgent. We previously found that citreoviridin, one of toxic mycotoxins derived from fungal species, can suppress lung cancer cell growth by inhibiting the activity of ectopic ATP synthase, but has limited effect on normal cells. Citreoviridin suppresses mitogen-activated protein kinase/extracellular signal-regulated kinase signaling by site-specific dephosphorylation of HSP90AB1 on Serine 255 in gefitinib non-resistant lung cancer CL1-0 cells and xenograft model. We are curious whether signaling pathways underlying citreoviridin-treated gefitinib-acquired resistant lung cancer cells are different. In this study, we showed that citreoviridin inhibited cell proliferation and anchorage-dependent growth of gefitinib-acquired resistance NCI-H1975 cells with EGFR T790M mutation. Furthermore, we explored the dynamic molecular response by temporal phosphoproteomic approach. We identified 1476 phosphopeptides corresponding to 738 phosphoproteins and quantified 1901 phosphorylation sites. There were 274 phosphosites corresponding to 174 phosphorylated proteins significantly differential expressed. Functional enrichment analysis demonstrated that citreoviridin treatment affected chromatin organization, cell cycle and apoptosis. Interestingly, we found that citreovirdin suppressed cell proliferation by site-specific phosphorylation of topoisomerase on serine 1106. Citreovirdin induced double strands breaks, and then leaded to DNA damage response. The DNA lesions triggered cells to cell cycle arrest at S phase for repairing or apoptosis for cell death. The results indicated that citreoviridin could potentially be a therapeutic agent against gefitinib-resistant NSCLC.
Project description:Gefitinib, an epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI), induces substantial clinical responses for non-small cell lung cancer (NSCLC) cells harboring EGFR activating mutations, but most of them invariably develop resistance. By generating a gefitinib resistance (PC9GR) from a human NSCLC-derived drug sensitive cell line (PC9), we studied differences of transcription dynamics between them by the aid of a computational decoupling of hidden regulatory signals from time course gene expression profiles. Given a collection of transcription factors (TFs) and their regulatory targets, the method captured temporally-synchronized shifts in evolving expression of target genes sharing each TF regulatory unit, and drew underlying regulatory signals. The analysis identified sterol regulatory element binding protein 1 (SREBP-1) as a key regulatory agent that facilitates the maintenance of drug tolerance, involving transcription controls of a G1-specific cyclin dependent kinase inhibitor whose expression was specifically elevated in PC9, but in turn, reduced in PC9GR Gefitinib-resistance cell line (PC9GR) was established derived from lung adenocarcinoma cell line PC9. PC9 cells and PC9GR cells were treated with the four different conditions, control (No treatment), EGF-treatment, gefitinib-treatment, and both gefitinib and EGF-treatment. In each condition, the gene expression was measured at 26 time points during 24 hrs.
Project description:Purpose: To characterize microRNA signatures for tolerance, persistence and resistance to EGFR tyrosine kinase inhibitors (TKIs) in human lung cancer. Methods: microRNA profiles of gefitinib- and osimertinib-tolerant cells in PC9 and HCC827 cells were generated by deep microRNA sequencing using Illumina. In addition, microRNA profiles of PC9 subpopulations cells with characterizations of persistence and resistance to gefitinib were generated by deep microRNA sequencing. The mappable reads were aligned to the human genome and miRbase using Bowtie. Results: We identified a specific microRNA profile distinguishing tolerance, persistence and resistance to gefitinib or osimertinib from parental human lung cancer cells with mutated EGFR. The expressions of those microRNAs in lung cancer cells were validated by qRT-PCR. Functionally, knocking down top-upregulated microRNAs reduced the tolerance, persistence and resistance to gefitinib or osimertinib in those tolerant and resistant cells. Conversely, overexpression of those microRNAs enhanced the tolerance and resistance to EGFR inhibition in cells sensitive to gefitinib and osimertinib. Conclusions: Our work identifies a panel of microRNAs that mediate EGFR-TKI tolerance and resistance in lung cancer. Our study provides potential non-coding targets to improve the efficacy of EGFR-TKIs therapy in cancer pagtients.
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.
Project description:Cryptotanshinone (CTS) is a lipophilic constituent of Salvia miltiorrhiza, with a broad-spectrum anticancer activity. We have observed that CTS enhances the efficacy of gefitinib in human lung cancer H1975 cells, yet little is known about its molecular mechanism. To explore how CTS enhances H1975 cell sensitivity to gefitinib, we figured out differential proteins of H1975 cells treated by gefitinib alone or in combination with CTS using label-free liquid chromatography-mass spectrometry (LC-MS). Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and protein-protein interaction (PPI) bioinformatic analyses of the differential proteins were performed. CTS enhanced H1975 cell sensitivity to gefitinib in vitro and in vivo, with 115 and 128 differential proteins identified respectively. GO enrichment, KEGG analysis, and PPI network comprehensively demonstrated that CTS mainly impacted the redox process and fatty acid metabolism in H1975 cells. Moreover, three differential proteins were validated by RT-qPCR and Western blot. In conclusion, we used a proteomic method to study the mechanism of CTS enhancing gefitinib sensitivity in H1975 cells. Our finding reveals the potential protein targets of CTS in overcoming gefitinib resistance which may be therapeutical targets in lung cancer.
Project description:The Epidermal Growth Factor Receptor (EGFR) regulates a diverse set of biological processes including cell growth, proliferation, and differentiation. Deregulation of the EGFR pathway has been implicated in a variety of human diseases including cancer. Gefitinib and erlotinib are tyrosine kinase inhibitors (TKIs) that have demonstrated clinical benefit for patients with Non-small cell lung cancer (NSCLC) and EGFR activating mutations. However, patients invariably acquire resistance to TKI treatment through a number of mechanisms. We utilized in vitro models of NSCLC with EGFR activating mutations and derived three isogenic cell lines with acquired resistance to gefitinib. We next studied genomewide mRNA expression in resistance and wild type cells and their effect in the reprogramming of pathways in lung cancer cell line models..
Project description:The Epidermal Growth Factor Receptor (EGFR) regulates a diverse set of biological processes including cell growth, proliferation, and differentiation. Deregulation of the EGFR pathway has been implicated in a variety of human diseases including cancer. Gefitinib and erlotinib are tyrosine kinase inhibitors (TKIs) that have demonstrated clinical benefit for patients with Non-small cell lung cancer (NSCLC) and EGFR activating mutations. However, patients invariably acquire resistance to TKI treatment through a number of mechanisms. We utilized in vitro models of NSCLC with EGFR activating mutations and derived three isogenic cell lines with acquired resistance to gefitinib. We next studied genomewide mRNA expression in resistance and wild type cells and their effect in the reprogramming of pathways in lung cancer cell line models..
Project description:Analysis of gene expression profiles for gefitinib-tolerant cells derived from single cells. The hypothesis tested here was that a small population of cancer cells contribute to tolerance status in a bulk of EGFR mutated lung cancer cells. Results provide important infromnation of the tolerance to the EGFR tyrosine kinase inhibitor, gefitinib, such as upregualtion of cancer-stemness related genes.