| 1. |
- Gritli Linde, Amel, 1959, et al.
(författare)
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Effects of suramin on polyamine metabolism in B16 murine melanoma cells
- 1998
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Ingår i: Anticancer Res. - 0250-7005. ; 18:2A, s. 855-62
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Tidskriftsartikel (refereegranskat)abstract
- Polyamines and their biosynthetic enzymes, such as ornithine decarboxylase (ODC) and S-adenosylmethionine decarboxylase (AdoMetDC), are crucial for normal and neoplastic cell growth and differentiation. Suramin inhibits the growth of several tumor cells by affecting various intracellular targets, but its effects on polyamines are not known. In this study, the effects of suramin on some parameters of polyamine metabolism in B16 melanoma cells were investigated in vitro. Suramin increased cellular ODC activity and ODC mRNA levels, whereas the drug was directly inhibitory to the enzyme. AdoMetDC was not affected. Cellular putrescine levels were enhanced by suramin, whereas spermidine and spermine pools were unaltered. Cells cultured in the presence of suramin showed decreased cellular polyamine transport, but no direct inhibitory effect on the polyamine transporter could be found. Fluorescence spectroscopy demonstrated a direct interaction between suramin and spermine. It may be concluded that suramin affects polyamine metabolism, and that its effects in some respects are opposite to those of alpha-difluoromethylomithine (DFMO), a specific inhibitor of ODC.
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| 2. |
- Gritli Linde, Amel, 1959, et al.
(författare)
-
Opposing effects of suramin and DL-alpha-difluoromethylornithine on polyamine metabolism contribute to a synergistic action on B16 melanoma cell growth in vitro
- 1998
-
Ingår i: Anticancer Res. - 0250-7005. ; 18:2A, s. 863-70
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Tidskriftsartikel (refereegranskat)abstract
- Polyamines are crucial for normal and neoplastic cell growth. Treatment with the polyanionic drug suramin has pronounced antigrowth activity in several tumor cell lines, but its clinical use has been hampered by its toxicity. We have earlier shown that suramin affects cellular polyamine metabolism and transport, and that these effects were, in some respects, opposite to those of alpha-difluoromethylomithine (DFMO), a specific inhibitor to ornithine decarboxylase, a key metabolic enzyme for polyamines. DFMO has been used in anticancer trials, although with limited success. Combinations of suramin and DFMO were, hence, evaluated in vitro and were found to strongly inhibit B16 melanoma cell proliferation. DFMO alone induced melanoma cell differentiation, and suramin used in combination with DFMO did not abrogate this DFMO-induced differentiation. Synergy analysis demonstrated a pronounced growth-inhibitory synergism between suramin and DFMO. The results suggest that the efficacy of combinations of DFMO with suramin or its analogues should be further explored, especially in cells requiring high levels of polyamines for their growth.
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