We analysed six malignant peripheral nerve sheath tumors (MPNSTs) from four patients using metaphase preparations and compared the results with those obtained by using comparative genomic ...hybridization (CGH). All six tumors showed structural and numerical chromosomal aberrations, mostly of chromosomes 1, 5, 7–10, 14–17, 19, 21, and 22. The number of chromosomes per tumor cell ranged from 42 to 104. We could not find a recurrent specific pattern of structural changes after comparing the MPNSTs of different patients. However, aberrations of different tumors from the same patient were nearly identical. In the four patients, we found a total of 117 breakpoints, mostly in 21q11.2 (seven times), in 8q11.2 and 14q10 (six times each), in 5q11.2 and 15q26 (four times each), in 8p11.2, 10q11.2, 16q22, 19q13.3, and 22q10 (three times each). In three MPNSTs, double minute chromosomes (dmin) we detected with metaphase investigations and high-level amplifications by using CGH, respectively. C-MYC gene amplification and loss of the P53 gene could be ruled out by locus-specific probes for the common gain of 8q and for losses of 17p. When comparing the CGH results with those of karyotyping an overlap in the most frequent gains in 7q, 8q, 15q, and 17q was observed. However, we found more frequent losses in 19q in the metaphase investigations.
The transcription factor hypoxia-inducible factor 1 (HIF1) is the crucial regulator of
genes that are involved in metabolism under hypoxic conditions, but information regarding the
transcriptional ...activity of HIF1 in normoxic metabolism is limited. Different tumor cells were treated
under normoxic and hypoxic conditions with various drugs that affect cellular metabolism. HIF1ff
was silenced by siRNA in normoxic/hypoxic tumor cells, before RNA sequencing and bioinformatics
analyses were performed while using the breast cancer cell line MDA-MB-231 as a model. Differentially
expressed genes were further analyzed and validated by qPCR, while the activity of the metabolites
was determined by enzyme assays. Under normoxic conditions, HIF1 activity was significantly
increased by (i) glutamine metabolism, which was associated with the release of ammonium, and
it was decreased by (ii) acetylation via acetyl CoA synthetase (ACSS2) or ATP citrate lyase (ACLY), respectively, and (iii) the presence of L-ascorbic acid, citrate, or acetyl-CoA. Interestingly, acetylsalicylic
acid, ibuprofen, L-ascorbic acid, and citrate each significantly destabilized HIF1ff only under normoxia.
The results from the deep sequence analyses indicated that, in HIF1-siRNA silenced MDA-MB-231
cells, 231 genes under normoxia and 1384 genes under hypoxia were transcriptionally significant
deregulated in a HIF1-dependent manner. Focusing on glycolysis genes, it was confirmed that HIF1
significantly regulated six normoxic and 16 hypoxic glycolysis-associated gene transcripts. However,
the results from the targeted metabolome analyses revealed that HIF1 activity affected neither the
consumption of glucose nor the release of ammonium or lactate; however, it significantly inhibited
the release of the amino acid alanine. This study comprehensively investigated, for the first time,
how normoxic HIF1 is stabilized, and it analyzed the possible function of normoxic HIF1 in the
transcriptome and metabolic processes of tumor cells in a breast cancer cell model. Furthermore, these
data imply that HIF1 compensates for the metabolic outcomes of glutaminolysis and, subsequently,
theWarburg effect might be a direct consequence of the altered amino acid metabolism in tumor cells.
We examined 10 malignant fibrous histiocytomas (MFHs) using metaphase preparations. Six tumors showed clonal structural and/or numerical chromosomal aberrations, and four tumors had normal ...karyotypes. For the most part, chromosomes 1, 3, 6, 9, 12, 16, 18, and 20 were involved in structural aberrations. The breakpoint regions most frequently were in 1p32, 3p25, and the centromeric region of chromosomes 1 and 16. There was a conspicuous loss in chromosome 18. We detected ring chromosomes in two tumors. One tumor showed a high percentage of near-haploid cells. Our results show many parallels to data which have already been published. MFHs include a broad spectrum of tumors of widely different histology and clinical course. So it is not surprising to find a cytogenetic diversity of chromosomal aberrations in this study.
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