RESUMO
Identification of the factors critical to the tumor-initiating cell (TIC) state may open new avenues in cancer therapy. Here we show that the metabolic enzyme glycine decarboxylase (GLDC) is critical for TICs in non-small cell lung cancer (NSCLC). TICs from primary NSCLC tumors express high levels of the oncogenic stem cell factor LIN28B and GLDC, which are both required for TIC growth and tumorigenesis. Overexpression of GLDC and other glycine/serine enzymes, but not catalytically inactive GLDC, promotes cellular transformation and tumorigenesis. We found that GLDC induces dramatic changes in glycolysis and glycine/serine metabolism, leading to changes in pyrimidine metabolism to regulate cancer cell proliferation. In the clinic, aberrant activation of GLDC correlates with poorer survival in lung cancer patients, and aberrant GLDC expression is observed in multiple cancer types. This link between glycine metabolism and tumorigenesis may provide novel targets for advancing anticancer therapy.
Assuntos
Carcinoma Pulmonar de Células não Pequenas/enzimologia , Transformação Celular Neoplásica , Glicina Desidrogenase (Descarboxilante)/metabolismo , Neoplasias Pulmonares/metabolismo , Sequência de Aminoácidos , Antígenos CD/metabolismo , Carcinoma Pulmonar de Células não Pequenas/genética , Carcinoma Pulmonar de Células não Pequenas/patologia , Moléculas de Adesão Celular Neuronais/metabolismo , Linhagem Celular Tumoral , Proteínas de Ligação a DNA/metabolismo , Proteínas Fetais/metabolismo , Glicina/metabolismo , Humanos , Dados de Sequência Molecular , Neoplasias/enzimologia , Neoplasias/genética , Proteínas de Ligação a RNA , Alinhamento de Sequência , Serina/metabolismo , Thermus thermophilus/enzimologia , Transplante HeterólogoRESUMO
BACKGROUND: Accurate mutational analysis, especially epidermal growth factor receptor (EGFR) mutations, of diagnostic biopsies from all Asian NSCLC patients is crucial to their clinical management, but faces problems. Here, we explore, within usual hospital constraints, the practicalities of incorporating mutational analysis in every newly diagnosed case of NSCLC, namely, maximizing tissue acquisition during the diagnostic procedure and determining the maximum quantity and quality of DNA sequence data available from these biopsies. METHODS: Sixty-eight Chinese patients were enrolled. Thirty-five underwent surgical resections for early-stage tumors. Thirty-three underwent diagnostic procedures, i.e., needle aspirates under bronchoscopic or computed tomographic/fluoroscopic guidance, or forceps biopsies via bronchoscopy. Separate samples for research purposes were obtained from these 33 patients during the diagnostic procedure. All samples were analyzed for mutations in EGFR exons 18 to 21, p53 exons 4 to 9, and Kras exon 2. RESULTS: No deaths occurred in this study. Success rates in obtaining sequence data from surgical samples versus low-volume samples for EGFR, p53, and Kras were 100% versus 85%, 100% versus 82%, and 100% versus 85%, respectively. Sequencing nine polymerase chain reaction products from each low-volume sample resulted in the exhaustion of all extracted DNA from three samples. CONCLUSIONS: Acquiring a separate low-volume lung biopsy sample for mutational analysis in lung cancer patients during the diagnostic procedure is feasible and may be a valuable complement to the usual diagnostic workflow in future.