Small-cell lung cancer (SCLC), an aggressive neuroendocrine tumor with early dissemination and dismal prognosis, accounts for 15-20% of lung cancer cases and ∼200,000 deaths each year. Most cases are inoperable, and biopsies to investigate SCLC biology are rarely obtainable. Circulating tumor cells (CTCs), which are prevalent in SCLC, present a readily accessible 'liquid biopsy'. Here we show that CTCs from patients with either chemosensitive or chemorefractory SCLC are tumorigenic in immune-compromised mice, and the resultant CTC-derived explants (CDXs) mirror the donor patient's response to platinum and etoposide chemotherapy. Genomic analysis of isolated CTCs revealed considerable similarity to the corresponding CDX. Most marked differences were observed between CDXs from patients with different clinical outcomes. These data demonstrate that CTC molecular analysis via serial blood sampling could facilitate delivery of personalized medicine for SCLC. CDXs are readily passaged, and these unique mouse models provide tractable systems for therapy testing and understanding drug resistance mechanisms.

Both technology platforms detected NSCLC CTCs. ISET detected higher numbers of CTCs including epithelial marker negative tumor cells. ISET also isolated CTM and permitted molecular characterization. Combined with our previous CellSearch data confirming CTC number as an independent prognostic biomarker for NSCLC, we propose that this complementary dual technology approach to CTC analysis allows more complete exploration of CTCs in patients with NSCLC.

S100 protein is a sensitive marker for melanomas and peripheral nerve sheath tumors. It is, however, expressed by other mesenchymal and epithelial tumors. Despite its low specificity, S100 protein is valuable for the diagnosis of desmoplastic melanomas and peripheral nerve sheath tumors, for which no specific marker is available. Sox10 is a neural crest transcription factor crucial for specification, maturation, and maintenance of Schwann cells and melanocytes. Anti-Sox10 antibody was applied to a variety of neural crest-derived tumors, mesenchymal and epithelial neoplasms, and normal tissues. Sox10 nuclear expression was found in 76 of 78 melanomas (97%) and 38 of 77 malignant peripheral nerve sheath tumors (49%) whereas S100 protein was expressed in 71 melanomas (91%) and 23 malignant peripheral nerve sheath tumors (30%). Sox10 was diffusely expressed in schwannomas and neurofibromas. Sox10 reaction was seen only in sustentacular cells of pheochromocytomas/paragangliomas, and occasionally carcinoid tumors from various organs, but it was not seen in the tumor cells. In normal tissues, Sox10 was expressed in Schwann cells, melanocytes, and myoepithelial cells of salivary, bronchial, and mammary glands. Sox10 reaction was not identified in any other mesenchymal and epithelial tumors except for myoepitheliomas and diffuse astrocytomas. Sox10 was expressed by metastatic melanomas and nodal capsular nevus in sentinel lymph nodes, but not by other lymph node components such as dendritic cells. Our results indicate that Sox10 will serve as a more sensitive and specific marker for the diagnosis of melanocytic and schwannian tumors than S100 protein.

Hsa-miR-205 is a highly accurate marker for lung cancer of squamous histology. The standardized diagnostic assay presented here can provide highly accurate subclassification of NSCLC patients.

Purpose: The monocarboxylate transporter 1 (MCT1) inhibitor, AZD3965, is undergoing phase I evaluation in the United Kingdom. AZD3965 is proposed, via lactate transport modulation, to kill tumor cells reliant on glycolysis. We investigated the therapeutic potential of AZD3965 in small cell lung cancer (SCLC) seeking rationale for clinical testing in this disease and putative predictive biomarkers for trial use.Experimental Design: AZD3965 sensitivity was determined for seven SCLC cell lines, in normoxia and hypoxia, and for a tumor xenograft model. Proof of mechanism was sought via changes in intracellular/ tumor lactate. Expression of MCT1 and related transporter MCT4 was assessed by Western blot analysis. Drug resistance was investigated via MCT4 siRNAi and overexpression. The expression and clinical significance of MCT1 and MCT4 were explored in a tissue microarray (TMA) from 78 patients with SCLC.Results: AZD3965 sensitivity varied in vitro and was highest in hypoxia. Resistance in hypoxia was associated with increased MCT4 expression. In vivo, AZD3965 reduced tumor growth and increased intratumor lactate. In the TMA, high MCT1 expression was associated with worse prognosis (P ¼ 0.014). MCT1 and hypoxia marker CA IX expression in the absence of MCT4 was observed in 21% of SCLC tumors.Conclusions: This study provides a rationale to test AZD3965 in patients with SCLC. Our results suggest that patients with tumors expressing MCT1 and lacking in MCT4 are most likely to respond. Clin Cancer Res; 20(4); 926-37. Ó2013 AACR.

The global physiological effects of glucocorticoids are well established, and the framework of transcriptional regulation by the glucocorticoid receptor (GR) has been described. However, the genes directly under GR control that trigger these physiological effects are largely unknown. To address this issue in a single cell type, we identified glucocorticoid-responsive genes in A549 human lung adenocarcinoma cells by microarray analysis and quantitative real-time PCR. Reduction of GR expression by RNA interference diminished the effects of dexamethasone on all tested target genes, thus confirming the essential role of GR in glucocorticoid-regulated gene expression. To identify primary GR target genes, in which GR is a component of the transciptional regulatory complex, we developed a strategy that uses chromatin immunoprecipitation to scan putative regulatory regions of target genes for sites occupied by specifically bound GR. We screened 11 glucocorticoid-regulated genes, and we identified GR-binding regions for eight of them (five induced and three repressed). Thus, our approach provides a means for rapid identification of primary GR target genes and glucocorticoid-response elements, which will facilitate analyses of transcriptional regulatory mechanisms and determination of hormone-regulated gene networks.

These guidelines can set the stage for reproducibility studies and the design of a clinically meaningful grading system for thymic epithelial tumors.

The glucocorticoid receptor (GR) activates or represses transcription depending on the sequence and architecture of the glucocorticoid response elements in target genes and the availability and activity of interacting cofactors. Numerous GR cofactors have been identified, but they alone are insufficient to dictate the specificity of GR action. Furthermore, the role of different functional surfaces on the receptor itself in regulating its targets is unclear, due in part to the paucity of known target genes. Using DNA microarrays and real-time quantitative PCR, we identified genes transcriptionally activated by GR, in a translation-independent manner, in two human cell lines. We then assessed in U2OS osteosarcoma cells the consequences of individually disrupting three GR domains, the N-terminal activation function (AF) 1, the C-terminal AF2, or the dimer interface, on activation of these genes. We found that GR targets differed in their requirements for AF1 or AF2, and that the dimer interface was dispensable for activation of some genes in each class. Thus, in a single cell type, different GR surfaces were used in a gene-specific manner. These findings have strong implications for the nature of gene response element signaling, the composition and structure of regulatory complexes, and the mechanisms of context-specific transcriptional regulation.