Project description:Human EGFR-mutated lung adenocarcinoma cell lines HCC4006, HCC827 and PC9 were treated with trametinib or DMSO to assess the impact on transcription.
Project description:Purpose: Multiple mechanims have been proposed that lead to reduced effectiveness of EGFR tyrosine kinase inhibitors (TKIs) in lung cancer and yet resistance to osimertinib and gefitinib still remains a challenge in the clinic. The goals of this study are to identify key genes contributing to tolerance and resistance to EGFR inhibition. Methods: mRNA profiles of gefitinib and osimertinib tolerant cells in PC9 and HCC827 cells were generated by deep sequencing using Illumina. In addition, mRNA profiles of cells (AALE, PC9 and HCC827) overexpressing with miR-147b or miR-21 and mRNA profiles of cells (H1975 and PC9ER) with miR-147b and miR-21 knocking down were generated by deep sequencing. The mappable reads were aligned to the human transcripts using Bowtie2 and gene abundance was estimated using RSEM. Results: Upregulation of miR-147b and miR-21 expression is related to tolerance and resistance to gefitinib and osimertinib in lung cancer. The signaling pathways of transcripts by knocking down miR-147b or miR-21 in resistant cells (H1975 and PC9ER) and by overexpressing miR-147b or miR-21 in both sensistive cells (HCC827 and PC9) and immortalized lung epithelial cells (AALE) are consistent with the key signaling pathways shown in tolerant cells to gefitinib and osimertinib in HCC827 and PC9 cells (HCC827GTR/OTR vs HCC827 and PC9GTR/OTR vs PC9). Conclusions: Our work identifies key signaling pathways that mediate EGFR-TKI tolerance and resistance in lung cancer. Our study provides potential targets to improve the efficacy of EGFR-TKIs therapy in cancer pagtients.
Project description:We previously reported that differential protein degradation of TKI-sensitive [L858R, del(E746-A750)] and resistant (T790M) epidermal growth factor receptor (EGFR) mutants upon erlotinib treatment correlates with drug sensitivity. However, the molecular mechanism remains unclear. We also reported SMAD ubiquitination regulatory factor 2 (SMURF2) as a stabilizer of EGFR in a ligase (E3) activity-dependent manner. Here, using in vitro and in vivo ubiquitination assays, mass spectrometry, and super-resolution microscopy, we show SMURF2-EGFR functional interaction is critical in receptor stability and TKI sensitivity. We found that L858R/T790M EGFR is a preferred substrate of SMURF2-UBCH5 (an E3-E2) complex-mediated K63-linked polyubiquitination, which preferentially stabilizes mutant receptor. We identified three lysine (K) residues (K721, 1037 and 1164) as the sites of ubiquitination and replacement of K to acetylation-mimicking asparagine (Q) at K1037 position in L858R/T790M background converts the stable protein sensitive to erlotinib-induced degradation. Using STochastic Optical Reconstruction Microscopy (STORM) imaging, we show that SMURF2 presence allows longer membrane retention of activated EGFR upon EGF treatment, whereas, siRNA-mediated SMURF2 knockdown fastens receptor endocytosis and lysosome enrichment. In an erlotinib-sensitive PC9 cells, SMURF2 overexpression increased EGFR levels with improved erlotinib tolerance, whereas, SMURF2 knockdown decreased EGFR steady state levels in NCI-H1975 and PC9-AR cells to overcome erlotinib and AZD-9291 resistance respectively. Additionally, disruption of the SMURF2-UBCH5 complex destabilized EGFR. Together, we propose that SMURF2-mediated preferential polyubiquitination of L858R/T790M EGFR may be competing with acetylation-mediated receptor internalization to provide enhanced receptor stability and that disruption of the E3-E2 complex may be an attractive alternate to overcome TKI resistance
Project description:The goals of this study are to compare the different transcriptome signiture between PC9 and MTAC-P with NGS-derived retinal transcriptome profiling (RNA-seq).
Project description:Considering the important role of circular RNAs (circRNAs) in cancers, we established AZD9291-resistant NSCLC cell lines (H1975/AZDR and HCC827/AZDR) and used microarray analysis to determine the circRNA expression profiles of the cells. The H1975/AZDR and HCC827/AZDR cell lines were induced by gradually increasing the drug concentration. CircRNA microarray expression profiles were obtained from H1975, HCC827, H1975/AZDR, and HCC827/AZDR cells and validated by quantitative reverse transcription PCR. Expression data were analyzed bioinformatically.
Project description:H1975 cells were treated with DMSO and erastin, respectively. Protein was extracted and separated using SDS-PAGE electrophoresis. MS analysis was performed and protein was identified and quantified using Proteome Discoverer™ 1.3 software using the SEQUEST® search engine.
Project description:Bulk RNA-Seq of PC9 xenograft tumors in different stages of response and resistance to Erlotinib treatment. A combination treatment is proposed in order to overcome Erlotinib drug resistance.
