| 1. |
- 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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| 2. |
- Roberts, Sigrid C, et al.
(författare)
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Leishmania donovani polyamine biosynthetic enzyme overproducers as tools to investigate the mode of action of cytotoxic polyamine analogs.
- 2007
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Ingår i: Antimicrob Agents Chemother. - 0066-4804. ; 51:2, s. 438-45
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Tidskriftsartikel (refereegranskat)abstract
- A number of anticancer and antiparasitic drugs are postulated to target the polyamine biosynthetic pathway and polyamine function, but the exact mode of action of these compounds is still being elucidated. To establish whether polyamine analogs specifically target enzymes of the polyamine pathway, a model was developed using strains of the protozoan parasite Leishmania donovani that overproduce each of the polyamine biosynthetic enzymes. Promastigotes overexpressing episomal constructs encoding ornithine decarboxylase (ODC), S-adenosylmethionine decarboxylase (ADOMETDC), or spermidine synthase (SPDSYN) revealed robust overproduction of the corresponding polyamine biosynthetic enzyme. Polyamine pools, however, were either unchanged or only marginally affected, implying that regulatory mechanisms must exist. The ODC, ADOMETDC, and SPDSYN overproducer strains exhibited a high level of resistance to difluoromethylornithine, 5'-{[(Z)-4-amino-2-butenyl]methylamino}-5'-deoxyadenosine, and n-butylamine, respectively, confirming previous observations that these agents specifically target polyamine enzymes. Conversely, augmented levels of polyamine biosynthetic enzymes did not affect the sensitivity of L. donovani promastigotes to pentamidine, berenil, and mitoguazone, drugs that were postulated to target the polyamine pathway, implying alternative and/or additional targets for these agents. The sensitivities of wild-type and overproducing parasites to a variety of polyamine analogs were also tested. The polyamine enzyme-overproducing lines offer a rapid cell-based screen for assessing whether synthetic polyamine analogs exert their mechanism of action predominantly on the polyamine biosynthetic pathway in L. donovani. Furthermore, the drug resistance engendered by the amplification of target genes and the overproduction of the encoded protein offers a general strategy for evaluating and developing therapeutic agents that target specific proteins in Leishmania.
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