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: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 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.
Project description:Even though small cell lung cancer (SCLC) has entered the age of broad genomic analysis, platinum-based chemotherapy remains the standard care for SCLC. Topotecan is the only approved agent for recurrent or progressive SCLC (1). In the absence of well-defined genomic biomarkers, clinical efficacy signals in genomically distinct subsets of SCLC could have been missed. Serine/Arginine Splicing Factor 1 (SRSF1) is a member of SR protein family. The deleterious consequences of overexpression of the SRSF1 proto-oncogene in human cancers suggest that there are complex mechanisms and pathways underlying SRSF1-mediated transformation (2). Whole exome and transcriptome sequencing of primary tumor SCLC from 99 Chinese patients has identified SRSF1 DNA amplification and mRNA over-expression which predicts poor survival in Chinese SCLC patients. In vitro and in vivo studies have demonstrated that SRSF1 is essential for tumorigenecity of SCLC and plays a key role in DNA repair and chemo-sensitivity. We did RNAseq on 79 small cell lung cancer patients' tumor sample and 7 normal lung tissue. We normalized the RNAseq data and did differential expression analysis. The deleterious consequences of overexpression of the SRSF1 proto-oncogene in human cancers suggest that there are complex mechanisms and pathways underlying SRSF1-mediated transformation.
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:Lineage transformation between lung cancer subtypes is a poorly understood phenomenon associated with resistance to treatment and poor patient outcomes. Here, we aimed to model this transition in order to define underlying biological mechanisms and identify potential avenues for therapeutic intervention. Small cell lung cancer (SCLC) is neuroendocrine in origin and, in contrast to non-SCLC (NSCLC), rarely contains mutations that drive the MAPK pathway. Likewise, NSCLCs that transform to SCLC concomitantly with development of therapy resistance downregulate MAPK signaling, suggesting an inverse relationship between pathway activation and lineage state. To test this, we activated MAPK in SCLC through conditional expression of mutant KRAS or EGFR, which revealed suppression of the neuroendocrine differentiation program via ERK. We found that ERK induces the expression of ETS factors, phenocopying ERK-mediated effects on transformation into the NSCLC-like phenotype. ATAC-seq demonstrated ERK-driven changes in chromatin accessibility at putative regulatory regions and global chromatin rewiring at neuroendocrine and ETS transcriptional targets. Further, induction of ETS factors as well as suppression of neuroendocrine differentiation were dependent on histone acetyltransferase activities of CBP/p300. Overall, we describe how the ERK-CBP/p300-ETS axis promotes a lineage shift between neuroendocrine and non-neuroendocrine lung cancer phenotypes and provide rationale for the disruption of this program during transformation-driven resistance to targeted therapy.
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.