Influence of betulin and 28-O-propynoylbetulin on proliferation and apoptosis of human melanoma cells (G-361).

INTRODUCTION: Pentacyclic triterpenes are a group of compounds known to have anticancer activity. One of the best characterized triterpenes is betulin, which can be isolated from bark of birch trees and modified into new compounds with various interesting medical properties. Betulin is involved in activation of the caspase cascade and promotes cell death. The aim of the study was to investigate the effect of betulin and its acetylenic derivative, 28-O-propynoylbetulin, on proliferation and apoptosis in a human melanoma cell line. MATERIALS AND METHODS: The G-361 melanoma cell line was used. To evaluate growth arrest and caspase-3 activity, cells were treated with betulin and its derivative at a wide range of concentrations from 0.1 to 10 µg/mL. RESULTS: Betulin and 28-O-propynoylbetulin inhibited cell proliferation in a concentration-dependent manner. The cell cycle analysis revealed an increase of the sub-G1 cell fraction (representing dead cells) after incubation of cells with betulin and 28-O-propynoylbetulin. The observed cytotoxic effects were more pronounced for 28-O-propynoylbetulin. Activity of caspase-3 in 28-O-propynoylbetulin treated cells was nearly 2-fold greater compared to cells incubated with betulin. DISCUSSION: Our results show that betulin and 28-O-propynoylbetulin were effective in inhibition of cell growth and induction of apoptosis in a human melanoma cell line. The addition of the propynoyl group at the C-28 hydroxyl group of betulin led to a greater proapoptotic and antiproliferative effect in comparison to unmodified betulin. These observations suggest that the obtained derivative is a potent anti-melanoma agent.

Effect of valproic acid on the proliferation and apoptosis of the human melanoma G-361 cell line.

Melanoma malignant is characterized by a high malignancy and low susceptibility to treatment. Due to these properties, there is a growing interest in compounds that would have the ability to inhibit proliferation, induce differentiation of tumor cells and initiate the apoptotic pathway. In vitro and in vivo research indicate that valproic acid (a histone deacetylase inhibitor) may have anti-cancer properties. In our study, the role of VPA on proliferation and apoptosis in G-361 human melanoma cell line was examined. Obtained results indicated that administration of VPA at concentrations above ≥ 1 mM led to significant inhibition of cell growth. Simultaneously, it was observed that VPA at higher concentrations (5 and 10 mM) caused an increase in caspase-3 activity.

The influence of chain microstructure of biodegradable copolyesters obtained with low-toxic zirconium initiator to in vitro biocompatibility.

Because of the wide use of biodegradable materials in tissue engineering, it is necessary to obtain biocompatible polymers with different mechanical and physical properties as well as degradation ratio. Novel co- and terpolymers of various composition and chain microstructure have been developed and applied for cell culture. The aim of this study was to evaluate the adhesion and proliferation of human chondrocytes to four biodegradable copolymers: lactide-coglycolide, lactide-co-ε-caprolactone, lactide-co-trimethylene carbonate, glycolide-co-ε-caprolactone, and one terpolymer glycolide-colactide-co-ε-caprolactone synthesized with the use of zirconium acetylacetonate as a nontoxic initiator. Chain microstructure of the copolymers was analyzed by means of ¹H and ¹³C NMR spectroscopy and surface properties by AFM technique. Cell adhesion and proliferation were determined by CyQUANT Cell Proliferation Assay Kit. After 4 h the chondrocyte adhesion on the surface of studied materials was comparable to standard TCPS. Cell proliferation occurred on all the substrates; however, among the studied polymers poly(L-lactide-coglycolide) 85 : 15 that characterized the most blocky structure best supported cell growth. Chondrocytes retained the cell membrane integrity evaluated by the LDH release assay. As can be summarized from the results of the study, all the studied polymers are well tolerated by the cells that make them appropriate for human chondrocytes growth.