Low concentrations of cytosine arabinoside, 6-thioguanine, actinomycin-D and aclacinomycin A stimulates the differentiation of normal human marrow myeloid progenitor cells

New Nanomedicine Approaches Using Gold-thioguanine Nanoconjugates as Metallo-ligands

Gold-thioguanine nanoconjugates (AuNP-TG) of size 3-4 nm were synthesized and the ratio between gold and 6-Thioguanine (TG) was estimated as ~1:1.5 using a cyanide digestion method and confirmed by flame atomic absorption spectroscopic analysis. AuNP-TG constructs showed high in vitro stability under different pH conditions and biologically relevant solutions for a period of 24 hours. Reaction of AuNP-TG with europium or platinum salts resulted in the formation of organized self-assembled metallo-networks.

Low concentrations of actinomycin D potentially cause therapeutic differentiation in human rhabdomyosarcoma cell line RD

Neoplastic transformation may be an alteration in the process of cell maturation that leads to an infinite capacity for proliferation. Because the cytodestruction caused by most drugs available for cancer chemotherapy is often accompanied by significant morbidity and poor response, the induction of differentiation has been proposed as an alternative approach to conventional anticancer therapy. We used human rhabdomyosarcoma cell line RD to analyze the differentiation process induced by actinomycin D, a drug of choice in the conventional treatment of rhabdomyosarcomas. Low concentrations of actinomycin D induced a terminal process of morphological and ultrastructural myogenic differentiation in rhabdomyosarcoma cells, which concluded with cell death. However, this potential therapeutic effect cannot be considered complete because of the presence of tumoral cells that are heterogeneous with respect to actinomycin D chemosensitivity. This heterogeneity led to the appearance of foci of resistant cells which, despite their greater degree of differentiation in comparison with the parental cell line, escaped from terminal myogenic differentiation. This subgroup of tumoral cells may be responsible for the failure of cytotoxic treatment.