Effects of electronegative LDL and native LDL on B16F10 mouse melanome cells.
Sangaletti L.A.*, Chammas R.**, Faine L.A.* and Abdalla, D.S.P*.
*Faculdade de Ciências Farmacêuticas/USP-SP, e-mail: fcf@edu.usp.br
**Faculdade de Medicina, Depto. de Radiologia/USP-SP.
Objective: To study the effects of electronegative LDL and native LDL on mouse melanoma B16F10 cells viability, proliferation and death.
Methods: Mouse melanome B16F10 cells were grown in RPMI 1640 medium supplemented with 10% fetal bovine serum in a humidified incubator with an atmosphere of 5% CO2 in air at 37 °C. Eletronegative LDL, LDL (-), and native LDL were isolated from blood plasma by ultracentifugation and separated from total LDL fraction by FPLC. Cells were incubated with 2-8 ug/mL of native LDL or LDL(-) for 24 and 48 h. Cell viability was determined by Tripan blue. Proliferation and death were determined by flow cytometry with propide iodide. The statistical analysis was performed by ANOVA in conjunction with Tukey´s test. The significance level was 0.05.
Results: Native LDL and LDL(-) induced cell proliferation at concentrations of 4 and 8 ug/ml in 24 h assay. LDL(-) demonstrated higher proliferative effect than native LDL at 8 ug/ml. It was observed decreased cell death by native LDL and LDL(-) in 24 and 48 h assay. This inhibitory effect on cell death was more pronounced on cells treated with native LDL. Native LDL and LDL(-) induced no alterations on cell viability.
Conclusion: Native LDL and LDL(-) stimulate cancer cell proliferation and inhibit the cell death. LDL(-) induced higher proliferative effect. These results are of significant importance, since a number of studies have demonstrated that the receptor - mediated uptake of LDL and its metabolism rate in certain cancer cells is higher. These proliferating effect of LDL is in agreement with recent sudies which have demonstrated that replicating cancer cells need large amounts of cholesterol for cell membrane synthesis.
Supported by CAPES, FAPESP and Instituto do Milênio REDOXOMA
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