Metabolomics,Unknown,Transcriptomics,Genomics,Proteomics

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Transcription profiling of rat DMBA induced mammary adeno carcinoma

ABSTRACT: Tumor hypoxia is relevant for tumor growth, metabolism and epithelial-to-mesenchymal transition (EMT). We report that hyperbaric oxygen (HBO) treatment induced mesenchymal-to-epithelial transition (MET) in a dimetyl-Î±-benzantracene induced mammary rat adenocarcinoma model, and the MET was associated with extensive coordinated gene expression changes and less aggressive tumors. One group of tumor bearing rats was exposed to HBO (2 bar, pO2 = 2 bar, 4 exposures Ã 90 minutes), whereas the control group was housed under normal atmosphere (1 bar, pO2 = 0.2 bar). Treatment effects were determined by assessment of tumor growth, tumor vascularisation, tumor cell proliferation, cell death, collagen fibrils and gene expression profile. Tumor growth was significantly reduced (~16%) after HBO treatment compared to day 1 levels, whereas control tumors increased almost 100 % in volume. Significant decreases in tumor cell proliferation, tumor blood vessels and collagen fibrils, together with an increase in cell death, are consistent with tumor growth reduction and tumor stroma influence after hyperoxic treatment. Gene expression profiling showed that HBO induced MET with coordinated expression of gene modules involved in cell junctions and attachments together with a shift towards non-tumorigenic metabolism. This leads to more differentiated and less aggressive tumors, and indicates that oxygen per se might be an important factor in the â??switchesâ?? of EMT and MET in vivo. HBO treatment also attenuated tumor growth and changed tumor stroma, by targeting the vascular system, having anti-proliferative and pro-apoptotic effects.

ORGANISM(S): Rattus norvegicus

SUBMITTER: Kjell Petersen

PROVIDER: E-TABM-718 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Project description:Tumor tissue heterogeneity is a well known feature of several solid tumors. Neuroblastic Tumors (NTs) is a group of paediatric cancers with a great tissue heterogeneity. Most of NTs are composed of undifferentiated, poorly differentiated or differentiating neuroblastic (Nb) cells with very few or absent Schwannian stromal (SS) cells: these tumors are grouped as Neuroblastoma (Schwannian stroma-poor). The remaining NTs are composed of abundant SS cells and classified as Ganglioneuroblastoma (Schwannian stroma-rich) intermixed or nodular and Ganglioneuroma. The importance to understand Nb and SS gene signatures in NTs, is to clarify the complex network mechanism of tumor growth and progression. In order to identify the Nb and SS cells gene signatures, we analyzed the gene expression profiling of 19 cases of neuroblastic tumors: 10 stroma poor (NTs-SP) and 9 stroma rich (NTs-SR), by high density oligonucleotide microarrays. Moreover, the analysis was performed in parallel on both whole and laser microdissected tumor samples: from 4 of 19 cases, was isolated different areas all composed of pure cellular populations. We performed genome wide expression analysis by using Affymetrix technology and we used two different approaches for data analysis: SAM (Significance Analysis of Microarrays) and a method based on Game Theory (GT), to identify genes differently expressed in SS and Nb cells. Differently from the SAM method, the analysis based on GT (Moretti et al. (2006)) gives the advantage of selecting relevant genes not only according to the expression profile of each single gene, but considering also gene interaction. Experiment Overall Design: Tissue samples from 10 primary neuroblastoma stroma-poor (NTs-SP) and 9 ganglioneuroblastoma/ganglioneuroma stroma-rich (NTs-SR) tumors, were obtained at diagnosis from patients at different clinical stage. Frozen samples of NTs-SP had a minimum content of 90% of malignant cells, while NTs-SR had more than 80-90% of schwannian stromal cells. Four out of 19 NTs: 2 neuroblastomas (Schwannian stoma-poor) and 2 ganglioneublastomas (Schwannian stroma-rich), were further analyzed with laser microdissection.

Project description:With the advent of potent second-line anti-androgen therapy, we and others have observed an increased incidence of androgen receptor (AR)-null small cell or neuroendocrine prostate cancer (SCNPC) in metastatic castration-resistant prostate cancer (mCRPC). Additionally, we have detected upregulated expression of MET and RET transcripts in SCNPC metastases relative to adenocarcinoma. Our study was designed to determine the effect of cabozantinib, a multi-targeted tyrosine kinase inhibitor that inhibits MET, RET and VEGFR2, on SCNPC patient-derived xenografts (PDX) in vivo. Surveillance of SU2C and University of Washington rapid autopsy mCRPC cohorts through RNA-Seq revealed that increased MET expression significantly correlated with loss of AR expression and activity. In vitro treatment of SCNPC PDX cells with AMG 337 had no impact on cell viability in LuCaP 93 (MET+/RET+) and LuCaP 173.1 (MET-/RET-), whereas cabozantinib decreased cell viability in LuCaP 93, but not in LuCaP 173.1. Notably, tumor volume was significantly decreased (p<0.001) with cabozantinib treatment in SCID mice bearing LuCaP 93 and LuCaP 173.1 tumors. Tissue analysis indicated that tumor cell proliferation was not inhibited by cabozantinib, but that cabozantinib decreased microvessel density (CD31) in LuCaP 93 (p<0.001) and LuCaP 173.1 (p<0.01) tumors. RNA-Seq and gene set enrichment analysis determined that hypoxia and glycolysis pathways were increased in cabozantinib treated tumors relative to control tumors. Thus, cabozantinib inhibited tumor growth in MET+/RET+ LuCaP 93 and MET-/RET- LuCaP 173.1 tumors in vivo and this activity was independent of MET or RET expression in LuCaP 173.1. Our data suggest that the most likely mechanism of tumor growth suppression is through disruption of the stromal architecture and cabozantinib may represent a potential therapy for patients with metastatic disease in tumor phenotypes that have a significant dependence on the tumor vasculature for survival and proliferation.

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Transcription profiling of rat DMBA induced mammary adeno carcinoma

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