ABSTRACT: SCLC transformation is one of the mechanisms of TKI resistance in lung cancer. To clarify its epigenetic changes, we used Chip-seq to detect the changes of H3K9me2 in pre-LUAD and post-SCLC transformation cells.
Project description:SCLC transformation is one of the mechanisms of TKI resistance in lung cancer. To clarify its epigenetic changes, we used RNA-seq to detect the changes of genes in pre-LUAD and post-SCLC transformation cells.
Project description:The histological transformation of lung adenocarcinoma (LUAD) to an aggressive neuroendocrine (NE) derivative resembling SCLC is a signature example of lineage plasticity in cancer.But the changes of gene expression need to be studied. We used microarrays to detail the global programme of gene expression under transformation and reversed transformation cells and identified distinct classes of up-regulated genes during this process.
Project description:The study was designed to identify the molecular changes that occur in EGFR mutant NSCLCs that become resistant to TKI by transforming to SCLC. Tyrosine kinase inhibitors (TKIs) are effective treatments for non-small cell lung cancers (NSCLCs) with epidermal growth factor receptor (EGFR) mutations. However, they do not lead to cures, and, on average, relapse occurs after one year of continuous treatment. In a subset of patients, a fundamental histological transformation from NSCLC to small cell lung cancer (SCLC) is observed in the resistant cancers, but the molecular changes associated with this transformation remain unknown. Analysis of a cohort of tumor samples and cell lines derived from resistant EGFR mutant patients with SCLC transformation revealed that RB is lost in 100% of these cases, but rarely in those that remain NSCLC. Global changes in gene expression, including increased neuroendocrine marker expression and absence of EGFR expression, are observed in cancers that transformed to SCLC. Consistent with their genetic and epigenetic similarities to classical SCLC, cell lines derived from resistant EGFR mutant SCLC biopsies are substantially more sensitive to ABT-263 treatment compared to those derived from resistant EGFR mutant NSCLCs. Together, these findings suggest that despite developing initially as EGFR mutant adenocarcinomas, this subset of resistant cancers ultimately take on many of the molecular and phenotypic characteristics of classical SCLC. Overall, we completed array CGH analysis on 4 tumor specimens from EGFR mutant, TKI-resistant patients. Three of these samples had transformed to SCLC and one remained NSCLC.
Project description:Histologic transformation to small cell lung cancer (SCLC) is an increasingly common resistance mechanism to EGFR tyrosine kinase inhibitors in EGFR mutant lung adenocarcinoma (LUAD) that is underdiagnosed in clinical practice due to the requirement for tissue biopsy. Early and accurate detection of transformed (t)SCLC has important prognostic and therapeutic implications. To address this unmet need, we first comprehensively profiled the epigenomes of metastatic lung tumors finding widespread epigenomic reprogramming during histologic transformation from LUAD to SCLC. We then utilized a novel approach for epigenomic profiling of cell-free DNA, which discriminated patients with EGFR mutant tSCLC from patients with EGFR mutant LUAD with greater than 90% accuracy. This first demonstration of the ability to accurately, and non-invasively, detect small cell transformation in patients with EGFR mutant LUAD through epigenomic cfDNA profiling is a critical step towards a new paradigm of diagnostic and therapeutic precision for patients with advanced lung cancer.
Project description:Lung adenocarcinoma (LUAD) and small cell lung cancer (SCLC) are thought to originate from different epithelial cell types in the lung. Intriguingly, LUAD can histologically transform into SCLC following treatment with targeted therapies. Here we designed models to follow the conversion of LUAD to SCLC and found the barrier to histological transformation converges on tolerance to Myc, which we implicate as a lineage-specific driver of the pulmonary neuroendocrine cell. Histological transformations are frequently accompanied by activation of the Akt pathway. Manipulating this pathway permitted tolerance to Myc as an oncogenic driver, producing rare, stem-like cells, transcriptionally resembling the pulmonary basal lineage. These findings suggest histological transformation may require the plasticity inherent to the basal stem cell, enabling tolerance to previously incompatible oncogenic driver programs.
Project description:Lung adenocarcinoma (LUAD) and small cell lung cancer (SCLC) are thought to originate from different epithelial cell types in the lung. Intriguingly, LUAD can histologically transform into SCLC following treatment with targeted therapies. Here we designed models to follow the conversion of LUAD to SCLC and found the barrier to histological transformation converges on tolerance to Myc, which we implicate as a lineage-specific driver of the pulmonary neuroendocrine cell. Histological transformations are frequently accompanied by activation of the Akt pathway. Manipulating this pathway permitted tolerance to Myc as an oncogenic driver, producing rare, stem-like cells, transcriptionally resembling the pulmonary basal lineage. These findings suggest histological transformation may require the plasticity inherent to the basal stem cell, enabling tolerance to previously incompatible oncogenic driver programs.