| 1. |
- Berglund, Erik, et al.
(författare)
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Intracellular concentration of the tyrosine kinase inhibitor imatinib in gastrointestinal stromal tumor cells.
- 2014
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Ingår i: Anti-Cancer Drugs. - 0959-4973 .- 1473-5741. ; 25:4, s. 415-22
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Tidskriftsartikel (refereegranskat)abstract
- Gastrointestinal stromal tumor (GIST) is the most common mesenchymal neoplasm in the gastrointestinal tract. In most GISTs, the underlying mechanism is a gain-of-function mutation in the KIT or the PDGFRA gene. Imatinib is a tyrosine kinase inhibitor that specifically blocks the intracellular ATP-binding sites of these receptors. A correlation exists between plasma levels of imatinib and progression-free survival, but it is not known whether the plasma concentration correlates with the intracellular drug concentration. We determined intracellular imatinib levels in two GIST cell lines: the imatinib-sensitive GIST882 and the imatinib-resistant GIST48. After exposing the GIST cells to imatinib, the intracellular concentrations were evaluated using LC-MS (TOF). The concentration of imatinib in clinical samples from three patients was also determined to assess the validity and reliability of the method in the clinical setting. Determination of imatinib uptake fits within detection levels and values are highly reproducible. The GIST48 cells showed significantly lower imatinib uptake compared with GIST882 in therapeutic doses, indicating a possible difference in uptake mechanisms. Furthermore, imatinib accumulated in the tumor tissues and showed intratumoral regional differences. These data show, for the first time, a feasible and reproducible technique to measure intracellular imatinib levels in experimental and clinical settings. The difference in the intracellular imatinib concentration between the cell lines and clinical samples indicates that drug transporters may contribute toward resistance mechanisms in GIST cells. This highlights the importance of further clinical studies to quantify drug transporter expression and measure intracellular imatinib levels in GIST patients.
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| 2. |
- Cirenajwis, Helena, et al.
(författare)
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Reduction of the putative CD44+CD24- breast cancer stem cell population by targeting the polyamine metabolic pathway with PG11047.
- 2010
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Ingår i: Anti-Cancer Drugs. - 0959-4973. ; 21:10, s. 897-906
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Tidskriftsartikel (refereegranskat)abstract
- Cancer stem cells (CSCs) are considered to be of particular concern in cancer as they possess inherent properties of self-renewal and differentiation, along with expressing certain genes related to a mesenchymal phenotype. These features favour the promotion of tumour recurrence and metastasis in cancer patients. Thus, the optimal chemotherapeutic treatment should target the CSC population, either by killing these cells and/or by inducing their transition to a more differentiated epithelial-like phenotype. Experiments were carried out on the trastuzumab-resistant human epidermal growth factor receptor 2-overexpressing breast cancer cell line JIMT-1 to unravel the chemotherapeutic effects of the polyamine analogue [N,N]bis(ethyl)-cis-6,7-dehydrospermine (PG11047) and of the polyamine biosynthetic inhibitor 2-difluoromethylornithine (DFMO) on the CD44CD24 CSC population. Furthermore, effects on the properties of self-renewal and epithelial/mesenchymal markers were also investigated. Treatment with PG11047 reduced the CD44CD24 subpopulation of JIMT-1 cells by approximately 50%, inhibited and/or reduced self-renewal capability of the CSC population, decreased cell motility and induced expression of mesenchymal to epithelial transition-associated proteins that are involved in promoting an epithelial phenotype. By contrast, DFMO slightly increased the CD44CD24 subpopulation, increased cell motility and the level of mesenchymal-related proteins. DFMO treatment reduced the self-renewal capability of the CSC population. Both PG11047 and DFMO reduced the expression of the human epidermal growth factor receptor 2 protein, which is correlated to malignancy and resistance to trastuzumab in JIMT-1 cells. Our findings indicate that treatment with PG11047 targeted the CSC population by interfering with several stem cell-related properties, such as self-renewal, differentiation, motility and the mesenchymal phenotype.
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| 3. |
- Ekblad, Lars, et al.
(författare)
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Reduced drug accumulation is more important in acquired resistance against oxaliplatin than against cisplatin in isogenic colon cancer cells.
- 2010
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Ingår i: Anti-Cancer Drugs. - 0959-4973. ; 21, s. 523-531
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Tidskriftsartikel (refereegranskat)abstract
- Preclinical studies have indicated that there is only partial cross-resistance between cisplatin and oxaliplatin. The molecular background for this is incompletely known. To investigate the differences in resistance, we rendered a colon cancer cell line (S1) resistant against cisplatin and oxaliplatin and characterized the subclones with regard to cross-resistance, platinum uptake, and gene expression profiles. Four oxaliplatin and four cisplatin-resistant cell lines were produced from S1 by step-wise increasing the concentrations of the drugs in the growth medium. Cytotoxicity was determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and platinum accumulation in cell lysates and DNA preparations by inductively coupled plasma mass spectroscopy. Gene expression was investigated by cDNA microarrays. The protein expression of the ATP-binding cassette B1 (ABCB1) was measured by immunohistochemistry. The cisplatin-resistant cell lines were 1.5-6.2-fold resistant against cisplatin and the oxaliplatin-resistant sublines 2.6-17-fold resistant against oxaliplatin. There was a limited degree of cross-resistance. Oxaliplatin resistance could be explained to a larger degree by reduced drug accumulation whereas mechanisms for increased tolerance against platinum incorporation in DNA seemed to be of higher importance for resistance against cisplatin. A greater number of ABC transporters were upregulated in the oxaliplatin-resistant cell lines compared with those selected for cisplatin resistance. ABCB1 was highly overexpressed in the three most oxaliplatin-resistant sublines, but significantly underexpressed in the two most cisplatin-resistant cell lines. This was also confirmed by immunohistochemistry. However, functional tests did not show any increase in ABCB1 transport activity in the oxaliplatin-resistant sub-lines compared with S1.
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| 4. |
- Laryea, Daniel, et al.
(författare)
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Characterization of the cytotoxic properties of the benzimidazole fungicides, benomyl and carbendazim, in human tumour cell lines and primary cultures of patient tumour cells
- 2010
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Ingår i: Anti-Cancer Drugs. - 0959-4973 .- 1473-5741. ; 21:1, s. 33-42
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Tidskriftsartikel (refereegranskat)abstract
- The benzimidazoles, benomyl and carbendazim, are fungicides suggested to target microtubules. Benomyl is metabolized to carbendazim, which has already been explored as an anticancer drug in phase 1 clinical trials. We further characterized the cytotoxic properties of benomyl and carbendazim in 12 human cell lines and in primary cultures of patient tumour cells with the overall aims of elucidating mechanisms of action and anticancer activity spectrum. Cytotoxicity was assessed in the short-term fluorometric microculture cytotoxicity assay and was correlated with the activity of other anticancer drugs and gene expression assessed by cDNA microarray analysis. Benomyl was generally more potent than its metabolite, carbendazim. Both showed high drug activity correlations with several established and experimental anticancer drugs, but modest association with established mechanisms of drug resistance. Furthermore, these benzimidazoles showed high correlations with genes considered relevant for the activity of several mechanistically different standard and experimental anticancer drugs, indicating multiple and broad mechanisms of action. In patient tumour samples, benomyl tended to be more active in haematological compared with solid tumour malignancies, whereas the opposite was observed for carbendazim. In conclusion, benomyl and carbendazim show interesting and diverse cytotoxic mechanisms of action and seem suitable as lead compounds for the development of new anticancer drugs.
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| 5. |
- Söderstjerna, Erika, et al.
(författare)
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Apoptosis induced by the potential chemotherapeutic drug N1, N11-Diethylnorspermine in a neuroblastoma cell line.
- 2010
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Ingår i: Anti-Cancer Drugs. - 0959-4973. ; 21:10, s. 917-926
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Tidskriftsartikel (refereegranskat)abstract
- Neuroblastoma is a highly malignant neoplasm found in young children. Although children with high-risk neuroblastoma respond to chemotherapy, relapses are common. On account of poor treatment outcome, new treatment strategies are constantly sought for neuroblastoma. Polyamine analogues are potentially novel substances for treatment of neuroblastoma. In this study, we have treated two neuroblastoma cell lines, SH-SY5Y and LA-N-1, with the spermine analogue N, N-Diethylnorspermine (DENSPM). SH-SY5Y was the most sensitive cell line, in which DENSPM treatment resulted in an inhibition of cell proliferation and an induction of cell death. The cell death induced by DENSPM treatment was apoptotic, as evidenced by cleavage of procaspase 3 and induction of caspase-3 activity. In contrast, DENSPM treatment only resulted in a slight inhibition of cell proliferation in LA-N-1 cells. There were several possible causes for the lower sensitivity to DENSPM treatment in the latter cell line when compared with SH-SY5Y cells. DENSPM-induced polyamine depletion was more extensive in SH-SY5Y cells than in LA-N-1 cells. This was partly because of a higher induction of the polyamine catabolic enzyme spermidine/spermine N-acetyltransferase in the cell line SH-SY5Y. The DENSPM-induced polyamine depletion was also caused by the inhibition of ornithine decarboxylase. LA-N-1 cells contained a higher level of the prosurvival protein survivin, which was further increased after DENSPM treatment. In contrast, DENSPM treatment resulted in a decreased survivin level in SH-SY5Y cells.
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