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:A comparison between parental K562 cells (CML) and two clones derived from this cell line : ImaR and PDR which are resistant against Imatinib mesylate and PD166326 respectively , two inhibitors of BCR-ABL. Keywords: gene expression, comparison
Project description:To reveal mechanisms for acquired imatinib resistance in gastrointestinal stromal tumor (GIST), we have analyzed several cell lines with resistance to imatinib.
Project description:Chronic myeloid leukemia is a malignant hematopoietic disorder distinguished by a presence of BCR-ABL fused oncogene with constitutive kinase activity. Although targeted therapy by tyrosine kinase inhibitors (TKI) markedly improved patient´s survival and quality of life, development of drug resistance remains a critical issue for a subset of patients. The most common mechanism of TKI resistance in CML patients is a mutation in BCR-ABL gene which makes oncogenic Bcr-Abl protein insensitive to TKI therapy. Mutation independent mechanisms of TKI resistance are less elucidated, but exosomes, extracellular vesicles excreted from normal and tumor cells were recently linked with cancer progression and drug resistance. We used an imatinib-sensitive CML cell line K562 and derived an imatinib-resistant subline K562IR by prolonged cultivation of cells in presence of imatinib. We demonstrated that exosomes isolated from K562IR cells are internalized by K562 cells and increase their survival in presence of 2µM imatinib. To characterize the exosomal cargo and to identify resistance-associated marker proteins, we performed a deep proteomic analysis of exosomes from both cell sublines using label free quantification (LFQ). In total, we identified over 3000 exosomal proteins including 31 proteins differentially abundant in exosomes derived from K562IR cells. Among the differential proteins were three massively upregulated membrane proteins in K562IR exosomes with surface localization: IFITM3, CD146, CD36. We verified the massive upregulation of the three proteins in K562IR exosomes and also in K562IR cells. Using flow cytometry, we further demonstrated potential of CD146 as cell surface marker associated with imatinib resistance in K562 cells.
Project description:Despite the success of imatinib in advanced gastrointestinal stromal tumor (GIST) patients, 50% of the patients experience resistance within two years of treatment underscoring the need to get better insight into the mechanisms conferring imatinib resistance. Here the microRNA and mRNA expression profiles in primary (imatinib-naïve) and imatinib-resistant GIST were examined. Fifty-three GIST samples harboring primary KIT mutations (exon 9; n=11/exon 11; n=41/exon 17; n=1) and comprising imatinib-naïve (IM-n) (n=33) and imatinib-resistant (IM-r) (n=20) tumors, were analyzed. The microRNA expression profiles were determined and from a subset (IM-n, n=14; IM-r, n=15) the mRNA expression profile was established. Ingenuity pathway analyses were used to unravel biochemical pathways and gene networks in IM-r GIST. Thirty-five differentially expressed miRNAs between IM-n and IM-r GIST samples were identified. Additionally, miRNAs distinguished IM-r samples with and without secondary KIT mutations. Furthermore 352 aberrantly expressed genes were found in IM-r samples. Pathway and network analyses revealed an association of differentially expressed genes with cell cycle progression and cellular proliferation thereby implicating genes and pathways involved in imatinib resistance in GIST. Differentially expressed miRNAs and mRNAs between IM-n and IM-r GIST were identified. Bioinformatic analyses provided insight into the genes and biochemical pathways involved in imatinib-resistance and highlighted key genes that may be putative treatment targets.
Project description:Resistant cells were generated by stepwise exposure to increasing concentrations of imatinib or nilotinib to establish 0.5 and 2 µM imatinib and 0.1 µM nilotinib resistant cells. This procedure was performed twice independently to establish biological replicates of TKI resistance. We analyzed genome-wide methylation to investigate changes in methylation during the development of TKI resistance.
Project description:Resistant cells were generated by stepwise exposure to increasing concentrations of imatinib or nilotinib to establish 0.5 and 2 µM imatinib and 0.1 µM nilotinib resistant cells. This procedure was performed twice independently to establish biological replicates of TKI resistance. We performed microarrays to analyze the changes in gene expression during the development of TKI resistance.
Project description:Resistant cells were generated by stepwise exposure to increasing concentrations of imatinib or nilotinib to establish 0.5 and 2 µM imatinib and 0.05 µM nilotinib resistant cells. This procedure was performed twice independently to establish biological replicates of TKI resistance. We performed microarrays (Clariom S) to analyze the changes in gene expression during the development of TKI resistance.