ABSTRACT
Cullin (CUL) 4A and 4B ubiquitin ligases are often highly accumulated in human malignant neoplasms and are believed to possess oncogenic properties. However, the underlying mechanisms by which CUL4A and CUL4B promote pulmonary tumorigenesis remain largely elusive. This study reports that CUL4A and CUL4B are highly expressed in patients with non-small cell lung cancer (NSCLC), and their high expression is associated with disease progression, chemotherapy resistance, and poor survival in adenocarcinomas. Depletion of CUL4A (CUL4Ak/d) or CUL4B (CUL4Bk/d) leads to cell cycle arrest at G1 and loss of proliferation and viability of NSCLC cells in culture and in a lung cancer xenograft model, suggesting that CUL4A and 4B are oncoproteins required for tumor maintenance of certain NSCLCs. Mechanistically, increased accumulation of the cell cycle-dependent kinase inhibitor p21/Cip1/WAF1 was observed in lung cancer cells on CUL4 silencing. Knockdown of p21 rescued the G1 arrest of CUL4Ak/d or CUL4Bk/d NSCLC cells, and allowed proliferation to resume. These findings reveal that p21 is the primary downstream effector of lung adenocarcinoma dependence on CUL4, highlight the notion that not all substrates respond equally to abrogation of the CUL4 ubiquitin ligase in NSCLCs, and imply that CUL4Ahigh/CUL4Bhigh may serve as a prognostic marker and therapeutic target for patients with NSCLC.
Subject(s)
Adenocarcinoma of Lung/metabolism , Cullin Proteins/metabolism , Cyclin-Dependent Kinase Inhibitor p21/metabolism , Lung Neoplasms/metabolism , Adenocarcinoma of Lung/pathology , Animals , Biomarkers/metabolism , Cell Proliferation , Cell Survival , Disease Progression , Drug Resistance, Neoplasm/physiology , Female , Heterografts , Humans , Lung Neoplasms/pathology , Mice , Mice, Nude , Prognosis , Signal Transduction/physiology , Ubiquitin/metabolismABSTRACT
The development of effective therapies against brain metastasis is currently hindered by limitations in our understanding of the molecular mechanisms driving it. Here we define the contributions of tumour-secreted exosomes to brain metastatic colonization and demonstrate that pre-conditioning the brain microenvironment with exosomes from brain metastatic cells enhances cancer cell outgrowth. Proteomic analysis identified cell migration-inducing and hyaluronan-binding protein (CEMIP) as elevated in exosomes from brain metastatic but not lung or bone metastatic cells. CEMIP depletion in tumour cells impaired brain metastasis, disrupting invasion and tumour cell association with the brain vasculature, phenotypes rescued by pre-conditioning the brain microenvironment with CEMIP+ exosomes. Moreover, uptake of CEMIP+ exosomes by brain endothelial and microglial cells induced endothelial cell branching and inflammation in the perivascular niche by upregulating the pro-inflammatory cytokines encoded by Ptgs2, Tnf and Ccl/Cxcl, known to promote brain vascular remodelling and metastasis. CEMIP was elevated in tumour tissues and exosomes from patients with brain metastasis and predicted brain metastasis progression and patient survival. Collectively, our findings suggest that targeting exosomal CEMIP could constitute a future avenue for the prevention and treatment of brain metastasis.
Subject(s)
Brain Neoplasms/genetics , Exosomes/metabolism , Gene Expression Regulation, Neoplastic , Hyaluronoglucosaminidase/genetics , Neovascularization, Pathologic/genetics , Tumor Microenvironment/genetics , Animals , Brain/metabolism , Brain/pathology , Brain Neoplasms/metabolism , Brain Neoplasms/mortality , Brain Neoplasms/pathology , Cell Line, Tumor , Cell Movement , Cell Proliferation , Chemokine CCL1/genetics , Chemokine CCL1/metabolism , Chemokine CXCL1/genetics , Chemokine CXCL1/metabolism , Cyclooxygenase 2/genetics , Cyclooxygenase 2/metabolism , Endothelial Cells/metabolism , Endothelial Cells/pathology , Exosomes/pathology , Humans , Hyaluronoglucosaminidase/metabolism , Mice , Mice, Inbred C57BL , Mice, Nude , Neoplasm Metastasis , Neovascularization, Pathologic/metabolism , Neovascularization, Pathologic/mortality , Neovascularization, Pathologic/pathology , Signal Transduction , Survival Analysis , Tumor Burden , Tumor Necrosis Factor-alpha/genetics , Tumor Necrosis Factor-alpha/metabolism , Xenograft Model Antitumor AssaysABSTRACT
Fine needle aspiration cytology (FNAC) of mediastinal masses allows for rapid on-site evaluation and the triaging of material for ancillary studies. However, surgical pathology is often considered to be the gold standard for diagnosis. This study examines the sensitivity and specificity of FNAC compared to a concurrent or subsequent surgical pathology specimen in 77 mediastinal lesions. The overall sensitivity for mediastinal mass FNAC was 78% and the overall specificity was 98%. For individual categories the sensitivity and specificity of FNAC was respectively as follows: inflammatory/infectious (33%, 99%), metastatic carcinoma (93%, 100%), lymphoma (84%, 97%), cysts (25%, 100%), soft tissue tumors (100%, 100%), paraganglioma (50%, 100%), germ cell tumor (100%, 99%), thymoma (87%, 94%), thymic carcinoma (60%, 100%), benign thymus (0%, 100%), and indeterminate (100%, 90%). For different locations within the mediastinum the sensitivity and specificity of FNAC was respectively as follows: anterosuperior mediastinum (80%, 98%), posterior mediastinum (33%, 95%), middle mediastinum (100%, 100%), and mediastinum, NOS (79%, 99%). Thus, mediastinal FNAC is fairly sensitive, very specific, and is a valuable technique in the diagnosis of mediastinal masses.
Subject(s)
Biopsy, Fine-Needle/methods , Mediastinal Neoplasms/diagnosis , Adolescent , Adult , Aged , Aged, 80 and over , Child , Female , Humans , Male , Mediastinal Neoplasms/pathology , Mediastinal Neoplasms/surgery , Middle Aged , Sensitivity and Specificity , Thoracic Surgical Procedures , Triage , Young AdultABSTRACT
(18)F-fluoro-2-deoxy-d-glucose positron emission tomography (PET) complements conventional imaging for diagnosing and staging lung cancer. Two literature-based meta-analyses suggest that maximum standardised uptake value (SUVmax) on PET has univariate prognostic value in nonsmall cell lung cancer (NSCLC). We analysed individual data pooled from 12 studies to assess the independent prognostic value of binary SUVmax for overall survival.After searching the published literature and identifying unpublished data, study coordinators were contacted and requested to provide data on individual patients. Cox regression models stratified for study were used.Data were collected for 1526 patients (median age 64â years, 60% male, 34% squamous cell carcinoma, 47% adenocarcinoma, 58% stage I-II). The combined univariate hazard ratio for SUVmax was 1.43 (95% CI 1.22-1.66) and nearly identical if the SUV threshold was calculated stratifying for histology. Multivariate analysis of patients with stage I-III disease identified age, stage, tumour size and receipt of surgery as independent prognostic factors; adding SUV (HR 1.58, 95% CI 1.27-1.96) improved the model significantly. The only detected interaction was between SUV and stage IV disease.SUV seems to have independent prognostic value in stage I-III NSCLC, for squamous cell carcinoma and for adenocarcinoma.
