Project description:Exposure to cigarette smoke creates a field of injury throughout the entire respiratory tract inducing genomic alterations that lead to an “at-risk” airway where and lung cancers develop. Lung squamous cell carcinoma (SCC) arises in the epithelial layer of the bronchial airways and is often preceded by the development of premalignant lesions(PMLs). The presence of high-grade persistent or progressive PMLs is a marker of increased lung cancer risk both at the lesion site elsewhere in the lung. Effective tools to identify and treat premalignant lesions at highest risk of progression to invasive carcinoma are lacking. We profiled via RNA-Seq airway brushing and biopsies (divided into two cohorts: discovery and validation) obtained from high-risk smokers undergoing lung cancer screening via serial auto-fluorescence bronchoscopy procedures. We identified four distinct molecular subtypes (Proliferative, Inflammatory, Secretory, and Normal) in the bronchial biopsies that correspond to a spectrum of biological and morphological alterations. The Proliferative subtype was enriched with dysplastic PMLs from current smokers that exhibit up-regulation of KRT5 and KI67 as well as metabolic and cell cycle pathways, and down-regulation of cilium-associated processes and FOXJ1 expression. Molecular subtype classification in the validation cohort biopsies replicated these significant clinical and biological associations. Airway brushes from normal fluorescing areas of the large airway classified as the Proliferative subtype specifically predicts the presence of biopsies of this same subtype. Within the Proliferative subtype, genes associated with interferon signaling and antigen processing and presentation were observed to be down-regulated among dysplastic biopsies that persistent or progress in the future. Innate and adaptive immune cells were computationally predicted to be depleted in these biopsies and this was confirmed via immunofluorescence staining of adjacent biopsies. These findings provide a proof of concept that molecular biomarkers of endobronchial biopsies can enhance histopathological grading and that immunoprevention strategies are an important future direction in intercepting the progression of PMLs to lung cancer.
Project description:Transcriptional profiling of hyperplastic, metaplastic, and dysplastic lesions of the bronchus in comparison with normal bronchial epithelium. The aim was to identify transcripts and cell signalling pathways associated with the development of isolated premalignant lesions and/or lesions combined with each other in the same bronchial epithelium.
Project description:While lung cancer is the leading cause of cancer death in the US, we have a limited understanding of the earliest molecular events preceding the onset of disease. Prior work has demonstrated that cigarette smoke creates a molecular “field of injury” throughout the airway epithelium and that there are distinct alterations in the airway transcriptome among smokers who have lung cancer. Molecular characterization of this airway “field of injury” in current and former smokers with premalignant lesions (PMLs) could provide novel insights into the earliest molecular events associated with lung carcinogenesis and identify relatively accessible biomarkers to guide lung cancer detection and early intervention. Using mRNA sequencing (mRNA-Seq), we profiled 82 cytologically normal bronchial airway epithelial cells collected during autofluorescence bronchoscopy from high-risk smokers with and without bronchial PMLs, 75 of which were used in downstream analyses. We identified 280 genes differentially expressed in the “field of injury” between subjects with (n=50) and without (n=25) PMLs (FDR<0.002), 81 of which were up-regulated in subjects with PMLs. Oxidative phosphorylation (OXPHOS), the electron transport chain (ETC), and mitochondrial protein transport pathways were strongly enriched among these up-regulated genes (FDR<0.05). We next demonstrated that OXPHOS activation is shared between the “field” and the PMLs with increased oxygen consumption and increased staining for mitochondrial markers in biopsies of PMLs from patients as well as an animal model of lung squamous cell carcinoma (SCC) premalignancy. The 280-gene signature also has a significant concordant relationship to gene expression changes identified in PMLs adjacent to lung SCC tumors, in lung SCC tumors, and in the cytologically normal airway of individuals with lung cancer (FDR<0.05). These findings suggest that these expression changes are reflective of early cancer-associated changes occurring throughout the respiratory tract, and that pathways such as OXPHOS may be targets for chemoprevention. We subsequently developed an airway gene expression biomarker that predicts the presence of PMLs (AUC=0.92, n=17 samples in test set) and show that changes in the biomarker score are associated with progression and regression of PMLs in an independent cohort (AUC=0.75, n=51 samples). The biomarker results indicate that molecular alterations in the field of injury are dynamic with progression or regression of PMLs, suggesting that these changes may be leveraged to stratify high-risk smokers with progressive disease into early intervention trials and monitor disease progression or recurrence.
Project description:Chromosomal instability is central to the process of carcinogenesis. The detection of somatic chromosomal alterations in small premalignant lesions genome-wide remains challenging since sample heterogeneity dilutes the aberrant cell information. We introduced an analytic metric termed "delta-θ", and applied this metric to a titrated cancer cell model using a pair of cancer cell line and matched lymphoblastoid cell line. We examined heterogeneous clinical specimens including bronchial biopsies and brushings with this metric. Distinctive genomic variation were successfully detected across the whole genome in invasive cancer cases (6/6), carcinoma in situ (3/3), and high grade dysplasia (severe or moderate) (3/11). We modeled titration series (100%, 25%, 12.5%, 6.3%, 3.1%, 1.6% and 0% tumor content) mixing the genomic DNA of the cell line pair. We also investigated 30 malignant/premalignant samples from 18 patients with heavy smoking histories (6 invasive lung cancer, 3 carcinoma in situ,15 dysplasia, 3 hyperplasia and 3 normal histology) using Illumina HumanOmni2.5 and Human 660w SNP microarrays. All of them were paired with matched reference blood DNA and analyzed.
Project description:Oral squamous cell carcinoma (OSCC) is a major cause of cancer-associated morbidity and mortality and may develop from oral premalignant lesions (OPL). An improved molecular classification of OPL may help refining prevention strategies. We identified two main OPL gene-expression subtypes, named immunological and classical, in 86 OPL (discovery dataset). A gene expression-based score was then developed to classify OPL samples from three independent datasets, including 17 (GSE30784),13 (GSE10174) and 15 (GSE85195) OPLs, into either one of the two gene-expression subtypes. Using the single sample gene set enrichment analysis, enrichment scores for immune-related pathways were different between the two OPL subtypes. In OPL from the discovery set, loss of heterozygosities (LOH) at 3p14, 17p13, TP53, 9p21 and 8p22 and miRNA gene expression profiles were analyzed. Deconvolution of the immune infiltrate was performed using the Microenvironment Cell Populations-counter tool. A multivariate analysis revealed that decreased miRNA-142-5p expression (P = 0.0484) and lower T-cell, monocytic and myeloid dendritic cells (MDC) immune infiltration (T-cells, P = 0.0196; CD8 T cells, P = 0.0129; MDC, P = 0.0481; and monocytes, P = 0.0212) were associated with oral cancer development in the immunological subtype only. In contrast, LOH at 3p14 (P = 0.0241), 17p13 (P = 0.0348) and TP53 (P = 0.004) were associated with oral cancer development in the classical subtype only. In conclusion, we identified 2 subtypes of OPLs, namely immune and classical, which may benefit from different and specific personalized prevention interventions.
Project description:Chromosomal instability is central to the process of carcinogenesis. The detection of somatic chromosomal alterations in small premalignant lesions genome-wide remains challenging since sample heterogeneity dilutes the aberrant cell information. We introduced an analytic metric termed "delta-θ", and applied this metric to a titrated cancer cell model using a pair of cancer cell line and matched lymphoblastoid cell line. We examined heterogeneous clinical specimens including bronchial biopsies and brushings with this metric. Distinctive genomic variation were successfully detected across the whole genome in invasive cancer cases (6/6), carcinoma in situ (3/3), and high grade dysplasia (severe or moderate) (3/11).
Project description:Lung squamous cell carcinoma (SCC) is thought to arise from premalignant lesions in the airway epithelium, therefore studying these lesions is critical for understanding lung carcinogenesis. We performed RNA sequencing on laser-microdissected representative cell populations along the SCC pathological continuum of patient-matched normal basal cells, premalignant lesions, and tumor cells. We discovered transcriptomic changes and identified genomic pathways altered with initiation and progression of SCC within individual patients. We used immunofluorescent staining to confirm gene expression changes in premalignant lesions and tumor cells, including increased expression of SLC2A1, CEACAM5, and PTBP3 at the protein level and increased activation of MYC via nuclear translocation. Cytoband enrichment analysis revealed coordinated loss and gain of expression in chromosome 3p and 3q regions, respectively, during carcinogenesis. This is the first gene expression profiling of airway premalignant lesions with patient-matched samples that provides insight into the mechanisms of stepwise lung carcinogenesis. Profiling of mRNA expression in laser-microdissected normal airway basal cells, premalignant airway lesions, and lung SCC tumor cells by massively parallel RNA sequencing.