Tumor contains small population of cancer stem cells (CSC) that are responsible for its maintenance and relapse. Analysis of these CSCs may lead to effective prognostic and therapeutic strategies for the treatment of cancer patients. We report here the identification of CSCs from human lung cancer cells using Aldefluor assay followed by fluorescence-activated cell sorting analysis. Isolated cancer cells with relatively high aldehyde dehydrogenase 1 (ALDH1) activity display in vitro features of CSCs, including capacities for proliferation, self-renewal, and differentiation, resistance to chemotherapy, and expressing CSC surface marker CD133. In vivo experiments show that the ALDH1-positive cells could generate tumors that recapitulate the heterogeneity of the parental cancer cells. Immunohistochemical analysis of 303 clinical specimens from three independent cohorts of lung cancer patients and controls show that expression of ALDH1 is positively correlated with the stage and grade of lung tumors and related to a poor prognosis for the patients with early-stage lung cancer. ALDH1 is therefore a lung tumor stem cell-associated marker. These findings offer an important new tool for the study of lung CSCs and provide a potential prognostic factor and therapeutic target for treatment of the patients with lung cancer.

SUMMARYAnalysis of molecular genetic markers in biological fluids has been proposed as a useful tool for cancer diagnosis. MicroRNAs (miRNAs) are small regulatory RNAs that are frequently dysregulated in lung cancer and have shown promise as tissue-based markers for its prognostication. The aim of this study was to determine whether aberrant miRNA expression can be used as a marker in sputum specimen for the diagnosis of non-small cell lung cancer (NSCLC). Experimental Design: Expressions of mature miRNAs, mir-21 and mir-155, were examined by real-time reverse transcription polymerase chain reaction (RT-PCR) and normalized to that of control miRNA, U6B, in sputum of 23 patients with NSCLC and 17 cancer-free subjects. The data was compared with conventional sputum cytology for the diagnosis of lung cancer. All endogenous miRNAs were present in sputum in a remarkably stable form and sensitively and specifically detected by real-time RT-PCR. Mir-21 expression in the sputum specimens was significantly higher in cancer patients (76.32 ± 9.79) than cancer-free individuals (62.24±3.82) (p<0.0001). Furthermore, overexpression of mir-21 showed highly discriminative receiver-operator characteristic (ROC) curve profile, clearly distinguishing cancer patients from cancer-free subjects with areas under the ROC curve at 0.902 ± 0.054. Detection of mir-21 expression produced 69.66% sensitivity and 100.00% specificity in diagnosis of lung cancer, as compared with 47.82% sensitivity and 100.00% specificity by sputum cytology. The measurement of altered miRNA expression in sputum could be a useful noninvasive approach for the diagnosis of lung cancer.

We have previously shown that miR-486-5p is one of the most downregulated micro RNAs in lung cancer. The objective of the study was to investigate the role of miR-486-5p in the progression and metastasis of non-small-cell lung cancer (NSCLC). We evaluated miR-486-5p expression status on 76 frozen and 33 formalin-fixed paraffin-embedded tissues of NSCLC by quantitative reverse transcriptase PCR to determine its clinicopathologic significance. We then performed function analysis of miR-486-5p to determine its potential roles on cancer cell migration and invasion in vitro and metastasis in vivo. We also investigated the target genes of miR-486-5p in lung tumorigenesis. miR-486-5p expression level was significantly lower in lung tumors compared with their corresponding normal tissues (P<0.0001), and associated with stage (P =0.0001) and lymph node metastasis of NSCLC (P = 0.0019). Forced expression of miR-486-5p inhibited NSCLC cell migration and invasion in vitro and metastasis in mice by inhibiting cell proliferation. Furthermore, ectopic expression of miR-486-5p in cancer cells reduced ARHGAP5 expression level, whereas miR-486-5p silencing increased its expression. Luciferase assay demonstrated that miR-486-5p could directly bind to the 3′-untranslated region of ARHGAP5. The expression level of miR-486-5p was inversely correlated with that of ARHGAP5 in lung tumor tissues (P =0.0156). Reduced expression of ARHGAP5 considerably inhibited lung cancer cell migration and invasion, resembling that of miR-486-5p overexpression. miR-486-5p may act as a tumor-suppressor contributing to the progression and metastasis of NSCLC by targeting ARHGAP5. miR-486-5p would provide potential diagnostic and therapeutic targets for the disease.

BackgroundWe hypothesized that, in patients with pulmonary fibrosis combined with emphysema, clinical characteristics and outcomes may differ from patients with pulmonary fibrosis without emphysema. We identified 102 patients who met established criteria for pulmonary fibrosis. The amount of emphysema (numerical score) and type of emphysema (centrilobular, paraseptal, or mixed) were characterized in each patient. Clinical characteristics, pulmonary function tests and patient survival were analysed.ResultsBased on the numerical emphysema score, patients were classified into those having no emphysema (n = 48), trivial emphysema (n = 26) or advanced emphysema (n = 28). Patients with advanced emphysema had a significantly higher amount of smoking in pack/years than patients with no emphysema or trivial emphysema (P < 0.0001). Median survival [1st, 3rd quartiles] of patients with advanced emphysema was 63 [36, 82] months compared to 29 [18, 49] months in patients without emphysema and 32 [19, 48] months in patients with trivial emphysema (P < 0.001). Median forced vital capacity (FVC) and total lung capacity (TLC) were higher in the advanced emphysema group compared to patients with no emphysema (P < 0.01 and P < 0.001, respectively), whereas median DLCO did not differ among groups and was overall low. Within the advanced emphysema group (n = 28), further characterization of the type of emphysema was performed and, within these subgroups of patients, survival was 75 [58, 85] months for patients with centrilobular emphysema, 75 [48, 85] months for patients with mixed centrilobular/paraseptal emphysema, and 24 [22, 35] months for patients with paraseptal emphysema (P < 0.01). Patients with advanced paraseptal emphysema had similar survival times to patients without emphysema.ConclusionsPatients with pulmonary fibrosis combined with advanced centrilobular or mixed emphysema have an improved survival compared with patients with pulmonary fibrosis without emphysema, with trivial emphysema or with advanced paraseptal emphysema.