Porphyrin bioasynthesis in human breast cancer. Preliminary mimetic in vitro studies

Considering both the wide spread utilization of porphyrins as photodiagnostic and phototherapeutic agents for tumours, and the limited information about the heme biosynthetic pathway in neoplastic tissues, a study of porphyrin biosynthesis in human breast adenocarcinoma, determining first the optima...

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Autores principales: Navone, N.M., Frisardi, A.L., Resnik, E.R., Del Batlle, C.A.M., Polo, C.F.
Formato: JOUR
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Acceso en línea:http://hdl.handle.net/20.500.12110/paper_02698951_v16_n2_p61_Navone
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Sumario:Considering both the wide spread utilization of porphyrins as photodiagnostic and phototherapeutic agents for tumours, and the limited information about the heme biosynthetic pathway in neoplastic tissues, a study of porphyrin biosynthesis in human breast adenocarcinoma, determining first the optimal working conditions, was initiated. The effect of temperature, maintenance time and the amount of precursor (δ-aminolevulinic acid, ALA) added and uptaken by normal and neoplastic tissue on the formation of porphyrins was determined. The optimal initial ALA concentration was approximately 34 μg/ml, while optimal temperature and maintenance time were 37°C and 24 h respectively. Under these conditions, porphyrin biosynthesis in tumoral tissue was about five times higher than normal. The functionality of the heme enzymes was indirectly measured by means of porphyrin chromatographic separation. Starting with ALA as substrate it was shown that the heme biosynthetic pathway was functional in the neoplastic tissue, up to the formation of protoporphyrinogen.