RESUMEN
Mitochondria of the yeast Saccharomyces cerevisiae contain enzymes Crd1p and Psd1p, which synthesize cardiolipin (CL) and phosphatidylethanolamine respectively. A previous study indicated that crd1Δ is synthetically lethal with psd1Δ. In this study, to identify novel genes involved in CL metabolism, we searched for genes that genetically interact with Psd1p, and found that deletion of FMP30 encoding a mitochondrial inner membrane protein results in a synthetic growth defect with psd1Δ. Although fmp30Δ cells grew normally and exhibited a slightly decreased CL level, fmp30Δpsd1Δ cells exhibited a severe growth defect and an about 20-fold reduction in the CL level, as compared with the wild-type control. We found also that deletion of FMP30 caused a defect in mitochondrial morphology. Furthermore, FMP30 genetically interacted with seven mitochondrial morphology genes. These results indicated that Fmp30p is involved in the maintenance of mitochondrial morphology and required for the accumulation of a normal level of CL in the absence of mitochondrial phosphatidylethanolamine synthesis.
Asunto(s)
Cardiolipinas/metabolismo , Proteínas de la Membrana/metabolismo , Mitocondrias/metabolismo , Proteínas Mitocondriales/metabolismo , Fosfatidiletanolaminas/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/metabolismo , Western Blotting , Electroforesis en Gel de Poliacrilamida , Potencial de la Membrana Mitocondrial , Proteínas de la Membrana/genética , Proteínas Mitocondriales/genética , Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/genéticaRESUMEN
BACKGROUND: Gefitinib has shown modest activity in patients with recurrent non-small cell lung cancer (NSCLC) after platinum-based chemotherapy. However, the activity of gefitinib as first-line chemotherapy remains unclear, especially unknown in elderly patients. A multicenter phase II trial was conducted to evaluate the efficacy and tolerability of gefitinib for elderly patients with chemotherapy-naïve NSCLC. METHODS: Elderly chemotherapy-naïve patients with advanced NSCLC, ECOG PS of 0-2, and adequate organ functions received 250 mg/day of gefitinib. The primary objective of this study was to determine the objective response rate (RR). Secondary endpoints were tolerability, disease-related symptom using lung cancer subscale (LCS) in FACT-L, progression free survival (PFS) and overall survival (OS). We investigated mutation status of the epidermal growth factor receptor (EGFR) gene in cases with available tumor samples. RESULTS: Fifty patients were enrolled, of whom 49 were eligible. Median age (range) was 80 (75-90) years. Thirty-two patients were female (65%) and 40 patients had adenocarcinoma (82%). The objective RR was 25% (CI 95%, 13-39). Median survival time was 10 months (CI 95%, 7-20) and 1-year survival rate was 50%. The most frequent adverse events were skin disorders (76%). Fifteen patients (30%) experienced toxicities >/=grade 3. There were four patients with possible interstitial lung disease including two treatment-related deaths. Symptom improvement rate using LCS was 49% at 4 weeks of gefitinib therapy. Tumor samples from 17 patients were analyzed for EGFR mutation status. EGFR mutations were detected in tumor tissues from 7 patients, of which 5 had partial responses (71%). CONCLUSIONS: Gefitinib monotherapy is effective and relatively well tolerated in chemotherapy-naïve elderly patients with advanced NSCLC. Gefitinib has potential as a first-line therapeutic option in elderly patients with advanced NSCLC.