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  • 1
    Keywords: EXPRESSION ; tumor ; carcinoma ; CELL ; Germany ; human ; INFORMATION ; HEPATOCELLULAR-CARCINOMA ; HISTORY ; GENE ; GENES ; HYBRIDIZATION ; DIFFERENTIATION ; TUMORS ; RESOLUTION ; DNA ; MECHANISM ; mechanisms ; ADENOMAS ; hepatocellular carcinoma ; PROGRESSION ; COMPARATIVE GENOMIC HYBRIDIZATION ; COPY NUMBER ; NUMBER ; CHROMOSOMAL-ABERRATIONS ; ABERRATIONS ; IN-SITU HYBRIDIZATION ; TUMOR-SUPPRESSOR GENE ; REGION ; INSTABILITY ; REGIONS ; ONCOGENE ; TRANSFORMATION ; ORAL-CONTRACEPTIVES ; CARCINOMAS ; IMBALANCES ; CLUSTER ; MOLECULAR-MECHANISM ; TUMOR-SUPPRESSOR ; INCREASE ; CLUSTER-ANALYSIS ; CHROMOSOMAL INSTABILITY ; CHIP ; tumor suppressor gene ; cluster analysis ; LOSSES ; GLYCOGEN-STORAGE-DISEASE ; genomic ; HUMAN HEPATOCELLULAR-CARCINOMA ; ARRAY CGH ; CHROMOSOMAL-ABNORMALITIES ; TUMOR-SUPPRESSOR GENES ; ARRAY-CGH ; LIVER-CELL ADENOMAS
    Abstract: Background & Alms: To gain more information about the molecular mechanisms leading to dedifferentiation of hepatocellular adenoma (HCA) and hepatocellular carcinoma (HCC), high-resolution array-based comparative genomic hybridization (array-CGH) was performed on 24 cases of HCC and 10 cases of HCA. Methods: DNA chips containing 6251 individual bacterial artificial chromosome/plasmid artificial chromosome clones were used. They allowed for a genome-wide resolution of 1 Mb and an even higher resolution of up to 100 kb for chromosome regions recurrently involved in human tumors and for regions containing known tumor-suppressor genes and oncogenes. Results: Copy number changes on the genomic scale were found by array-based comparative genomic hybridization in all cases. In HCC, gains of chromosomal regions 1q (91.6%), and 8q (58.3%), and losses of 8p (54%) were found most frequently. Hierarchic cluster analysis branched all HCA from HCC. However, in 2 adenomas with a known history of glycogenosis type I and adenomatosis hepatis gains of 1q were found, too. The critically gained region was narrowed down to bands 1q22-23. Although no significant differences in the mean number of chromosomal aberrations were seen between adenomas and well-differentiated carcinomas (2.7 vs 4.6), a significant increase accompanied the dedifferentiation of HCC (14.1 in HCC-G2 and 16.3 in HCC-G2/3; P 〈 .02). Dedifferentiation of HCC also was correlated closely to losses of 4q and 13q (P 〈 .001 and 〈 .005, respectively). Conclusions: The increased chromosomal instability during dedifferentiation of HCC leads to an accumulation of structural chromosomal aberrations and losses and gains of defined chromosome regions
    Type of Publication: Journal article published
    PubMed ID: 16979954
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  • 2
    Keywords: NF-KAPPA-B ; BREAST-CANCER ; TARGET ; MUTATIONS ; HEMATOPOIETIC STEM-CELLS ; ACUTE MYELOGENOUS LEUKEMIA ; RAPAMYCIN ; AML ; MEK INHIBITION ; CONSTITUTIVE PHOSPHORYLATION
    Abstract: In acute myeloid leukemia (AML), several signaling pathways such as the phosphatidylinositol-3-kinase/AKT and the mammalian target of rapamycin (PI3K/AKT/mTOR) pathway are deregulated and constitutively activated as a consequence of genetic and cytogenetic abnormalities. We tested the effectiveness of PI3K/AKT/mTOR-targeting therapies and tried to identify alterations that associate with treatment sensitivity. By analyzing primary samples and cell lines, we observed a wide range of cytotoxic activity for inhibition of AKT (MK-2206), mTORC1 (rapamycin) and PI3K/mTORC1/2 (BEZ-235) with a high sensitivity of cells carrying an MLL rearrangement. In vivo PI3K/mTOR inhibition delayed tumor progression, reduced tumor load and prolonged survival in an MLL-AF9(+)/FLT3-ITD+ xenograft mouse model. By performing targeted amplicon sequencing in 38 MLL-AF9(+) and 125 cytogenetically normal AML patient samples, we found a high additional mutation rate for genes involved in growth factor signaling in 79% of all MLL-AF9(+) samples, which could lead to a possible benefit of this cohort. PI3K/mTOR inhibition for 24 h led to the cross-activation of the ERK pathway. Further in vitro studies combining PI3K/mTOR and ERK pathway inhibition revealed highly synergistic effects in apoptosis assays. Our data implicate a possible therapeutic benefit of PI3K/mTOR inhibition in the MLL-mutated subgroup. Inhibiting rescue pathways could improve the therapeutic efficacy of PI3K-targeted therapies in AML.
    Type of Publication: Journal article published
    PubMed ID: 25322685
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