Project description:Insulin-like growth factor receptor-1 (IGF-1R) inhibition could be a relevant therapeutic approach in small cell lung cancer (SCLC) given the importance of an IGF-1R autocrine loop and its role in DNA damage repair processes. We assessed IGF-1R and pAkt protein expression in 83 SCLC human specimens. The efficacy of R1507 (a monoclonal antibody directed against IGF-1R) alone or combined with cisplatin or ionizing radiation (IR) was evaluated in H69, H146 and H526 cells in vitro and in vivo. Innovative genomic and functional approaches were conducted to analyze the molecular behavior under the different treatment conditions. A total of 53% and 37% of human specimens expressed IGF-1R and pAkt, respectively. R1507 demonstrated single agent activity in H146 and H526 cells but not in H69 cells. R1507 exhibited synergistic effects with both Cisplatin and IR in vitro. The triple combination R1507-Cisplatin-IR led to a dramatic delay in tumor growth compared to Cisplatin-IR in H526 cells. Analyzing the apparent absence of antitumoral effect of R1507 alone in vivo, we observed a transient reduction of IGF-1R staining intensity in vivo, concomitant to the activation of multiple cell surface receptors and intracellular proteins involved in proliferation, angiogenesis and survival. Finally, we identified that the nucleotide excision repair pathway (NER) was mediated after exposure to R1507-CDDP and R1507-IR in vitro and in vivo. In conclusion, adding R1507 to the current standard Cisplatin-IR doublet reveals remarkable chemo- and radiosensitizing effects in selected SCLC models and warrants to be investigated in the clinical setting. We used microarrays to investigate the effect of IGF-1R targetting on the global gene expression. Gene expression data from H526 xenografts under various treatment and time conditions Total mRNA from 33 NCI-H526 SCLC (small-cell lung cancer) xenografts was hybridized to Affymetrix HGU133 Plus 2.0 expression arrays. Log2 gene expression values were calculated using RMA. (A) To identify the molecular mechanisms involved in the response to R1507 alone along the treatment time, we performed global gene expression profiling in H526 xenografts at the following time points: baseline (vehicle), R1507 day 1 and R1507 day 7. (B) To identify the molecular mechanisms involved in the response to CDDP- and IR-R1507 combinations, we performed global gene expression profiling on mice bearing H526 xenografts treated with the following treatment conditions: vehicle, R1507 CDDP, IR, CDDP-R1507 and IR-R1507.

Project description:Radiotherapy has a critical role in the treatment of small cell lung cancer (SCLC). Effectiveness of radiation in SCLC remains limited as resistance results from defects in apoptosis. In the current study, we investigated whether using a Bcl-2/Bcl-XL inhibitor S44563 can enhance radiosensitivity of SCLC cells in vitro and in vivo. In vitro studies confirmed that S44563 induce apoptosis in SCLC cells by inducing hallmarks of apoptosis (cleaved caspase-3, sub-G1 fraction induction and induction of the mitochondrial caspase activation pathway). S44563 markedly enhanced sensitivity of H146 cells and H69 cells to radiation in clonogenic assay. In addition, the combination S44563 and cisplatin-based chemo-radiation showed a dramatic tumor growth delay and increased overall survival in mouse xenograft models. In vitro experiments demonstrated a greater induction of apoptosis (sub-G1 fraction and cleaved caspase-3) with the combination as well as in vivo caspase-3 immunostaining. This positive interaction between S44563 and radiation was greater when S44563 was given after the completion of the radiation, which may be explained by the radiation-induced over expression of anti-apoptotic proteins (Bcl-2 and Bcl-XL) through the NF-?B pathway activation. Taken together, these data underline the critical role of sequence administration of targeted therapies with conventional therapies. SCLC cells which survive to IR highly rely on the induction of anti apoptotic proteins in part through NF- ?B activation for their survival yielding to the concept of 'contextual oncogene addiction' to the Bcl-2/Bcl-XL pathway providing rational for targeting survival pathways to potentiate IR. For transcriptome analysis, 106 cells were seeded in T25 flasks, allowed to growth for 24 h, and then left untreated or treated with 2 Gy radiation. After 24 hours, cells were harvested, lysed for the extraction of RNA, and processed to analyze gene expression.The design of this study consists to 6 hybridizations in dual color with Agilent Human Genome 4x44K (design 014850). The reference is always the untreated condition.

Project description:Lung cancer is the leading cause of cancer death in the United States. Among the various subtypes of lung cancers, pulmonary neuroendocrine (NE) cancer, including small cell lung cancer (SCLC) and NE-non-small cell lung cancer (NE-NSCLC), is a particularly aggressive malignancy that is distinct from classic non–small cell lung cancer (NSCLC) in its metastatic potential and treatment response. Recently, the lineage-specific transcription factors Achaete-scute homolog 1 (ASCL1), NEUROD1, and POU2F3 have been reported to identify heterogeneity in pulmonary NE cancers. These transcription factors bind different genomic loci to regulate distinct gene programs in pulmonary NE cancers. However, the signaling pathways downstream of these transcription factors that distinguish these pulmonary NE cancer subtypes are not well characterized. Regulated protein secretion is critically involved in cell signaling and cell-cell communication events, and is known to be a hallmark associated with pulmonary NE tumors. Using a large-scale mass spectrometric approach, we performed quantitative secretomic analysis 13 cell lines including a pair of isogenic cell lines, i.e., an immortalized human bronchial epithelial cell and an ASCL1high NE NSCLC line. This panel also contained 6 additional ASCL1High and 5 NEUROD1High NE-lung cancer cell lines. From the conditioned media of the 13 cell lines, we identified and quantified 1,626 proteins. The NE-specific secretome is associated with a number of biological processes related to neurodevelopment. Further analysis of the upregulated proteins in ASCL1High subtype NE-lung cancer cells leads to the identification of IGFBP5 being a specific secreted marker for ASCL1High pulmonary NE cancer cells. Furthermore, IGFBP5 is also upregulated in the serum of a genetically modified mouse model of ASCL1High SCLC, as well as in human ASCL1High SCLC tumors. Mechanistically, ASCL1 binds to E-box elements in the IGFBP5 gene and directly regulates its transcription. Knockdown of ASCL1 in SCLC decreases IGFBP5 expression, which, in turn, leads to hyperactivation of the IGF-1R pathway. Pharmacological co-targeting of ASCL1 and IGF-1R signaling results in markedly synergistic, growth inhibitory effects in ASCL1High SCLC both in vitro and in vivo. Together, our quantitative proteomic analysis identifies a novel secreted marker and a new combination therapy for ASCL1High pulmonary NE cancer cells. In addition, we expect that the data sets will serve as an invaluable resource, providing the foundation for future mechanistic studies and biomarker discovery that helps delineate the molecular underpinnings of pulmonary NE tumors.

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Expression data from IGF-1R targeting in 33 NCI-H526 SCLC (small-cell lung cancer) xenografts

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