Abstract

IN VITRO CITOTOXICY EVALUATION OF CHITOSAN AND ?-LAPACHONE ON MELANOMA CELL LINES

Santos A.I.L., Barreto M.M.L., Silva E. C. and Amorim R.V.S.*

ABSTRACT

β-lapachone (β-LAP) has many physicochemical properties as a cancer related drug, but due to its high toxicity and poor solubility it has limited medical use. This project aimed to evaluate the potential of depolymerized water-soluble chitosan (dpCh) in conjugation to β-LAP, through cytotoxicity studies tested in vitro, as an adjuvant to improve the efficiency of β-LAP and its effects over melanoma cancer cells. In this study were used two cell lines, B16-F10 (murine melanoma) BCRJ-0046 and macrophage lineage RAW 264.7, the morphological essays and cytotoxicity were assessed using the Trypan Blue test and MTT colorimetric method (3-[4,5-dimethylthiazol-2yl]-2,5-diphenyltetrazolium bromide thiazolyl blue) the result was evaluated by exposing these cell to dpCh, β-LAP and the β-LAP-dpCh conjugated prepared using a simple coacervation in different mass ratio. The results showed that dpCh could inhibit the growth of the tumor cell line, by approximately 95%, in concentrations above 80 μg/mL, and that this effect was dose-dependent. However, to Macrophage this concentration inhibited in aprox. 45%. β-Lapachone inhibited the growth of the tumor line B16-F10 in 98%, in the highest concentration tested (500 μg/mL). However, this compounds also inhibited the growth of Macrophages cells, in 60%. The IC50 for the dpCh was 3.62μg/mL, and the β-Lapachone presented an IC50 of 2.35μg/ml. With the β-LAP-dpCh conjugate the best result was obtained with the mass ratio 1:2, with inhibition of cell viability in almost 100%, with tumor cells. Besides, in this same proportion, the cytotoxic effect for the Macrophage strain was approx. 10%, showing that the conjugation of both compounds can reduce cytotoxicity for normal cell lines.

Keywords: Water-soluble chitosan; Naphthoquinone; Melanoma B10-F16; Adjuvant.