Project description:We report the gene expression profiles by NGFR knockdown in H460 and H1299 cell lines and reveal that NGFR ablation activates p53 target gene expression. We examined gene expression in two different non-small-cell lung cancer cell lines, one with wild-type p53 and the other without p53.
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:Breast cancer subtypes identified in genomic studies have different underlying genetic defects. Mutations in the tumor suppressor p53 occur more frequently in estrogen receptor (ER) negative, basal-like and HER2-amplified tumors than in luminal, ER positive tumors. Thus, because p53 mutation status is tightly linked to other characteristics of prognostic importance, it is difficult to identify p53's independent prognostic effects. The relation between p53 status and subtype can be better studied by combining data from primary tumors with data from isogenic cell line pairs (with and without p53 function). In this study, the p53-dependent gene expression signatures of four cell lines (MCF-7, ZR-75-1, and two immortalized human mammary epithelial cell lines) were identified by comparing p53-RNAi transduced cell lines to their parent cell lines. Cell lines were treated with vehicle only or doxorubicin to identify p53 responses in both non-induced and induced states. Each cell line displayed unique patterns of gene expression, but cell type specific trends were evident. A common gene expression signature associated with p53 loss across all four cell lines was identified. This signature showed overlap with the signature of p53 loss in primary breast tumors and predicted relapse-free survival and overall survival in independent test data sets. Keywords: untreated x treated
Project description:This study compares the outcomes and safety of two standard treatment options called microwave ablation and surgical wedge resection in patients with non-small cell lung cancer, sarcoma and colorectal cancer that has spread to other parts of the body (metastatic). Microwave ablation is designed to kill tumor cells by heating the tumor until the tumor cells die. A wedge resection is a procedure that involves the surgical removal of a small, wedge-shaped piece of lung tissue to remove a small tumor or to diagnose lung cancer. Comparing these two treatment options may help researchers learn which method works better for the treatment of non-small cell lung cancer, metastatic sarcoma, and metastatic colorectal cancer.
Project description:The p53 tumor suppressor regulates multiple context-dependent tumor suppressive programs. Although p53 is mutated in ~90% of small cell lung cancer (SCLC) tumors, how p53 mediates tumor suppression in this context is unknown. Here, using a mouse model of SCLC in which endogenous p53 expression can be conditionally and temporally regulated, we show that SCLC tumors maintain a requirement for p53 inactivation. However, we identified tumor subtype heterogeneity between SCLC tumors such that p53 reactivation induces a canonical senescence response in a subset of tumors, while, in others, p53 induces a non-apoptotic form of cell death that culminates in necrosis. We pinpointed the cyclophilin family of peptidyl prolyl cis-trans isomerases as critical determinants of a p53-induced transcriptional program that is specific to SCLC tumors and cell lines that are poised to undergo p53- mediated necrosis. Importantly, inhibition of cyclophilin isomerase activity, or genetic ablation of specific cyclophilin genes, suppresses p53-mediated necrosis by limiting p53 transcriptional output without impacting p53 chromatin binding. Our study demonstrates that a previously unappreciated intertumoral heterogeneity in SCLC can influence the biological response to p53 restoration, describes a novel mechanism of p53-regulated cell death, and uncovers putative mechanisms for the treatment of this most-recalcitrant tumor type.
Project description:The p53 tumor suppressor regulates multiple context-dependent tumor suppressive programs. Although p53 is mutated in ~90% of small cell lung cancer (SCLC) tumors, how p53 mediates tumor suppression in this context is unknown. Here, using a mouse model of SCLC in which endogenous p53 expression can be conditionally and temporally regulated, we show that SCLC tumors maintain a requirement for p53 inactivation. However, we identified tumor subtype heterogeneity between SCLC tumors such that p53 reactivation induces a canonical senescence response in a subset of tumors, while, in others, p53 induces a non-apoptotic form of cell death that culminates in necrosis. We pinpointed the cyclophilin family of peptidyl prolyl cis-trans isomerases as critical determinants of a p53-induced transcriptional program that is specific to SCLC tumors and cell lines that are poised to undergo p53- mediated necrosis. Importantly, inhibition of cyclophilin isomerase activity, or genetic ablation of specific cyclophilin genes, suppresses p53-mediated necrosis by limiting p53 transcriptional output without impacting p53 chromatin binding. Our study demonstrates that a previously unappreciated intertumoral heterogeneity in SCLC can influence the biological response to p53 restoration, describes a novel mechanism of p53-regulated cell death, and uncovers putative mechanisms for the treatment of this most-recalcitrant tumor type.
Project description:The p53 tumor suppressor regulates multiple context-dependent tumor suppressive programs. Although p53 is mutated in ~90% of small cell lung cancer (SCLC) tumors, how p53 mediates tumor suppression in this context is unknown. Here, using a mouse model of SCLC in which endogenous p53 expression can be conditionally and temporally regulated, we show that SCLC tumors maintain a requirement for p53 inactivation. However, we identified tumor subtype heterogeneity between SCLC tumors such that p53 reactivation induces a canonical senescence response in a subset of tumors, while, in others, p53 induces a non-apoptotic form of cell death that culminates in necrosis. We pinpointed the cyclophilin family of peptidyl prolyl cis-trans isomerases as critical determinants of a p53-induced transcriptional program that is specific to SCLC tumors and cell lines that are poised to undergo p53- mediated necrosis. Importantly, inhibition of cyclophilin isomerase activity, or genetic ablation of specific cyclophilin genes, suppresses p53-mediated necrosis by limiting p53 transcriptional output without impacting p53 chromatin binding. Our study demonstrates that a previously unappreciated intertumoral heterogeneity in SCLC can influence the biological response to p53 restoration, describes a novel mechanism of p53-regulated cell death, and uncovers putative mechanisms for the treatment of this most-recalcitrant tumor type.
Project description:Unlike other EBV-associated human tumors, nearly 100% wild-type p53 gene is found in NPC, p53 protein is also frequently found to accumulate in NPC biopsies. However, the role of p53 in EBV-positive nasopharyngeal carcinoma is unclear. The expression profiles of mRNAs and miRNAs of EBV-positive NPC cells are unknown. To elucidate the function of p53 in EBV-positive NPC, we used the CRISPR-Cas9 gene editing system to p53 knockout C666-1 cells with Epstein-Barr virus and performed mRNA and miRNA sequencing in p53 KO C666-1 and their control cells. Gene Ontology (GO), KEGG and STRING analyses were implemented to identify significant functions, pathways of differentially expressed mRNAs. Through comparative analysis of p53-regulated genes from EBV-positive C666-1 cells and EBV-negative HONE2 cells with p53 target genes from 16 high throughput data sets, we found that the number of target genes and KEGG pathways downregulated by p53 in EBV-positive C666-1 cells were much less than in EBV-negative HONE2 cells, but “p53 signaling pathway” and related cell cycle arrest and apoptosis genes were significantly downregulated after knockout of p53 gene in C666-1 cells. To explore the effect of p53 on cell cycle and apoptosis, we established stable p53 C666-1-KO cell lines with stable expression of exogenous p53-WT and their control cell lines. Using the established cell lines, we observed that stable expression of p53 repressed cell proliferation, increased cell apoptosis and blocked G1/S phase progression. In conclusion, our results show that the accumulated p53 protein in EBV-positive C666-1 cells still has some tumour suppressor functions such as blocking cell-cycle progression and promoting apoptosis, but the ability of p53 to downregulate gene expression is inhibited.