Turmeric ethanol extract (Curcuma longa L.) reduces apoptosis and promotes canine osteosarcoma cell proliferation

Abstract Curcuma longa L., also known as turmeric, has been widely studied for its various therapeutic properties, including antineoplastic action. The ethanolic extract of the plant contains several phenolic compounds, especially curcumin. Osteosarcoma is a predominant bone tumor in dogs and humans, characterized by high metastatic potential and an unfavorable prognosis. The aim of this study was to investigate the effects of turmeric ethanol extract on canine osteosarcoma cells from established culture. The cells were cultured and treated with different curcumin concentrations (0, 10 μM, 20 μM, 50 μM, 100 μM, and 1000 μM) and exposure times (24h, 48h, and 72h). We first performed tetrazolium reduction technique (MTT) assay and calculated IC50. An immunocytochemistry assay was performed after extract treatment to verify the expression of mutated p53 and therefore study the proliferative potential of malignant cells; Bcl-2 and Ki-67 were used to assess apoptosis and the degree of malignancy, respectively. The extract enhanced the proliferation of canine osteosarcoma cells, reaching 3,819.74% at 50 μM of curcumin. The extract also significantly altered the expression of mutated p53 and Ki-67 proteins but not that of Bcl-2, suggesting that it did not induce this antiapoptotic pathway. Overall, these results are prerequisite to better understanding how natural compounds such as turmeric ethanolic extract affect cell proliferation and could be used to treat various diseases.

摘要：姜黄（Curcuma longa L.）又名郁金，其多种治疗活性（包括抗肿瘤作用）已被广泛研究。该植物的乙醇提取物含有多种酚类化合物，尤以姜黄素（curcumin）为著。骨肉瘤是犬与人类中高发的骨肿瘤，其特征为高转移潜能与不良预后。本研究旨在探究姜黄乙醇提取物对已构建的犬骨肉瘤细胞株的作用。将细胞进行培养后，分别以不同浓度姜黄素（0、10μM、20μM、50μM、100μM及1000μM）与不同暴露时长（24h、48h、72h）进行处理。首先采用四唑盐还原试验（MTT，tetrazolium reduction technique）检测，并计算半数抑制浓度（IC50）。提取物处理后，通过免疫细胞化学试验检测突变型p53（mutated p53）的表达，以此分析恶性细胞的增殖潜能；分别以Bcl-2与Ki-67评估细胞凋亡程度与肿瘤恶性级别。实验结果显示，该提取物可促进犬骨肉瘤细胞增殖，在姜黄素浓度为50μM时增殖率可达3819.74%。该提取物还可显著改变突变型p53与Ki-67的蛋白表达水平，但对Bcl-2的表达无明显影响，提示其未激活该抗凋亡通路。综上，本研究结果可为深入理解姜黄乙醇提取物等天然化合物调控细胞增殖的机制提供基础，亦可为多种疾病的治疗提供潜在参考。