Small RNA expression signatures of gastrointestinal stromal tumors: associations to imatinib resistance and patient outcome
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ABSTRACT: We performed miRNA expression profiling in a series of fresh-frozen neoadjuvantly imatinib treated gastrointestinal stromal tumors (GIST), using a microarray approach. Significant differentially expressed miRNAs among imatinib-resistant and imatinib-sensitive groups were identified using SAM analysis. Agilent microarray platform with probes matching 903 human miRNAs was used to determine miRNA expression profiles in 17 GISTs (imatinib-sensitive and 7 imatinib-resistant). To validate the microarray platform, the expression levels of selected miRNAs were evaluated using qRT-PCR.
Project description:We performed microRNA expression profiling in a series of fresh-frozen neoadjuvantly imatinib-treated and non-treated gastrointestinal stromal tumors (GIST), using a microarray approach. Significant differentially expressed microRNAs among imatinib-treated and non-treated groups were identified using SAM analysis. Agilent microarray platform with probes matching 903 human microRNAs was used to determine miRNA expression profiles in 34 GISTs (19 imatinib-treated and 15 non-treated). Re-analysis of GSE45901 for 17 imatinib-treated GISTs. To validate the microarray platform, the expression levels of selected microRNAs were evaluated using qRT-PCR.
Project description:We performed miRNA expression profiling in a series of de novo DLBCLs, transformed DLBCLs and non-neoplastic lymph nodes using a microarray approach. Significant differentially expressed miRNAs among groups were identified using SAM analysis. Agilent microarray platform containing 470 miRNAs was used to determine miRNA expression profiles in 45 DLBCL cases (32 de novo and 13 transformed) and 10 lymph nodes. To validate the microarray platform, the expression levels of selected miRNAs were evaluated using qRT-PCR.
Project description:In order to improve our understanding of microRNA (miRNA) deregulation in melanoma development and possible consequences for patient survival, miRNA expression profiles were determined, using an array based approach, in melanoma tumors, melanoma cell lines and normal melanocytes. Differentially expressed miRNAs were evaluated in relation to clinical characteristics, patient prognosis in terms of melanoma-specific survival, and mutational status for BRAF and NRAS. Agilent microarray platform containing 470 miRNAs was used to determine miRNA expression profiles in 3 normal melanocytes (as non-neoplastic control), 21 melanoma cell lines and 16 clinical samples from fresh frozen regional lymph node metastases. To validate the microarray platform, the expression levels of some miRNAs were evaluated using RT-PCR and the correlation between the two platforms was assessed using Pearson Correlation analysis. The results obtained were further verified and confirmed by RT-PCR in an independent set of melanoma samples. Association between deregulated miRNAs and survival was determined by Univariate Cox proportional hazards model and log rank test.
Project description:The gene expression profile of TAMs microbead isolated from freshly obtained human GISTs were compared in tumors that were untreated, responding to imatinib (sensitive), or resistant to imatinib (resistant) The Affymetrix Human Genome U133A 2.0 platform was used
Project description:Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal neoplasms of the digestive tract. The majority of GIST patients eventually develop resistance to imatinib therapy. To identify the responsible mechanisms, we investigated the differentially expressed mRNAs and circRNAs in imatinib-resistant GISTs using SBC ceRNA microarrays. We found that 107 mRNAs and 521 circRNAs were significantly differentially expressed between imatinib-naïve and imatinib-resistant GIST tissue samples. qRT-PCR analyses validated that circ-BRIP1, circ-EPHB4 and circ-RECQL4 and their host genes were upregulated in imatinib-resistant GISTs, and circ-BRIP1, circ-EPHB4, and RECQL4 were associated with imatinib resistance, tumor relapse and progression, and metastasis in GIST patients. The expression levels of circ-BRIP1, circ-EPHB4 and their host genes were also evaluated using TMAs with 150 human GISTs. The expression level of EPHB4 was significantly increased in high-grade GISTs in comparison to low-grade GISTs and correlated with imatinib resistance. Specifically, we first developed a method for high-throughput analysis of the expression of differentially expressed circRNAs by ISH-IHC in a set of FFPE-tissue microarrays in GIST. Our results also suggested a possible role for circ-BRIP1, circ-EPHB4, and their host genes in the progression of GISTs.
Project description:The gene expression profile of TAMs microbead isolated from freshly obtained human GISTs were compared in tumors that were untreated, responding to imatinib (sensitive), or resistant to imatinib (resistant) The Affymetrix Human Genome U133A 2.0 platform was used TAMs were microbead isolated from 12 untreated, 5 sensitive, and 4 resistant tumors. Tumors were obtained freshly from the operating room from consenting patients using an IRB approved protocol. Tumors were digested using collagenase and TAMs isolated using microbead negative selection for KIT, CD3, and CD56 followed by positive selection for CD14.
Project description:We performed miRNA expression profiling in a series of adrenocortical carcinomas, adrenocortical adenomas and normal adreno cortex using a microarray approach. Significant differentially expressed miRNAs among groups were identified using SAM analysis. Agilent microarray platform containing 903 miRNAs was used to determine miRNA expression profiles in 4 normal cortices, 26 adenomas and 22 adrenocortical carcinomas. SAM analysis was adopted to identify significant differentially expressed miRNAs between groups. SAM survival analysis was used to determine the association between miRNA expression and survival among carcinoma cases. The expression levels of candidate prognostic miRNAs were evaluated using qRT-PCR in the same cohort of adrenocortical carcinomas and association with survival was evaluated using Kaplan Meier curves and log rank tests.
Project description:We performed miRNA expression profiling in a series of fresh-frozen neoadjuvantly imatinib treated gastrointestinal stromal tumors (GIST), using a microarray approach. Significant differentially expressed miRNAs among imatinib-resistant and imatinib-sensitive groups were identified using SAM analysis.
Project description:Both imatinib-sensitive and imatinib-resistant cells were compared in the absence of imatinib. The resistant cells in the presence of imatinib were compared to the sample in the absence of imatinib. The sample from the resistant cells in the presence of imatinib was labelled in duplicate to assess false-positive rates.
Project description:K562 cells when grown with erythropeitin do not respond to Imatinib. Here we are comparing the gene expression profile from imatinib resistant and sensitive cells.