Abstract：
OBJECTIVE: Isogarcinol, a natural compound extracted from the fruits of Garcinia oblongifolia, has potential chemopreventive activity. This study aimed to elucidate the anti-tumor effects and mechanism of action of isogarcinol on nasopharyngeal carcinoma (NPC).
METHODS: Isogarcinol was isolated from Garcinia oblongifolia by using chromatographic separation. The anti-tumor effects of isogarcinol in NPC cells were tested by MTT assay, flow cytometry, wound healing assay, western blotting, transwell assay, colony formation assay, immunofluorescence, and transmission electron microscopy (TEM). The anti-tumor efficacy in vivo was evaluated in NPC cells xenograft models.
RESULTS: Functional studies revealed that isogarcinol inhibited the proliferation, colony formation, migration and invasion abilities of NPC cells in vitro. Isogarcinol caused mitochondrial damage to overproduce reactive oxygen species through reducing the mitochondrial membrane potential and ΔΨm. Isogarcinol also substantially inhibited NPC cells growth in a xenograft tumor model without any obvious toxicity when compared with paclitaxel (PTX). Mechanistic studies have illustrated that isogarcinol increased the Bax/Bcl-2 ratio, cleaved caspase-3, and cytoplasmic cytochrome C levels to induce mitochondrial apoptosis. The ROS overproduction by isogarcinol could suppress EMT pathway via decreasing the levels of p-Akt and Snail. Furthermore, isogarcinol promoted the conversion of LC3-Ⅰ to LC3-Ⅱ, but increased p62 level to block autophagic flux, resulting in the accumulation of damaged mitochondria to promote autophagic cell death in NPC cells.
CONCLUSIONS: This study provides a new theoretical foundation for the anti-tumor application of Garcinia oblongifolia and confirms that isogarcinol could be developed as a candidate drug for NPC treatment with low toxicity.
METHODS: Isogarcinol was isolated from Garcinia oblongifolia by using chromatographic separation. The anti-tumor effects of isogarcinol in NPC cells were tested by MTT assay, flow cytometry, wound healing assay, western blotting, transwell assay, colony formation assay, immunofluorescence, and transmission electron microscopy (TEM). The anti-tumor efficacy in vivo was evaluated in NPC cells xenograft models.
RESULTS: Functional studies revealed that isogarcinol inhibited the proliferation, colony formation, migration and invasion abilities of NPC cells in vitro. Isogarcinol caused mitochondrial damage to overproduce reactive oxygen species through reducing the mitochondrial membrane potential and ΔΨm. Isogarcinol also substantially inhibited NPC cells growth in a xenograft tumor model without any obvious toxicity when compared with paclitaxel (PTX). Mechanistic studies have illustrated that isogarcinol increased the Bax/Bcl-2 ratio, cleaved caspase-3, and cytoplasmic cytochrome C levels to induce mitochondrial apoptosis. The ROS overproduction by isogarcinol could suppress EMT pathway via decreasing the levels of p-Akt and Snail. Furthermore, isogarcinol promoted the conversion of LC3-Ⅰ to LC3-Ⅱ, but increased p62 level to block autophagic flux, resulting in the accumulation of damaged mitochondria to promote autophagic cell death in NPC cells.
CONCLUSIONS: This study provides a new theoretical foundation for the anti-tumor application of Garcinia oblongifolia and confirms that isogarcinol could be developed as a candidate drug for NPC treatment with low toxicity.
摘要：
目标：异甘精，从藤黄果实中提取的一种天然化合物，具有潜在的化学预防活性。本研究旨在阐明异丁香酚对鼻咽癌的抗肿瘤作用及其作用机制。
方法：采用色谱分离法从藤黄藤中分离异甘精。MTT法检测异甘氨酚对鼻咽癌细胞的抗肿瘤作用,流式细胞术,伤口愈合试验，西方印迹,transwell分析，集落形成试验,免疫荧光，和透射电子显微镜（TEM）。在NPC细胞异种移植模型中评估体内抗肿瘤功效。
结果：功能研究显示，异甘醇抑制细胞增殖，菌落形成,鼻咽癌细胞的迁移和侵袭能力。异甘氨酚通过降低线粒体膜电位和ΔWm引起线粒体损伤以过度产生活性氧。与紫杉醇（PTX）相比，异甘氨醇在异种移植肿瘤模型中也基本上抑制了NPC细胞的生长，而没有任何明显的毒性。机理研究表明，异甘氨酚增加Bax/Bcl-2的比例，裂解的caspase-3和细胞质细胞色素C水平诱导线粒体凋亡。异甘氨酚的ROS过量产生可以通过降低p-Akt和Snail的水平来抑制EMT途径。此外，异甘氨酚促进LC3-Ⅰ向LC3-Ⅱ的转化,但是增加p62水平来阻断自噬通量，导致受损线粒体的积累促进NPC细胞的自噬性细胞死亡。
结论：本研究为藤黄的抗肿瘤应用提供了新的理论基础，证实了异甘醇可作为鼻咽癌治疗的候选药物，且毒性低。
方法：采用色谱分离法从藤黄藤中分离异甘精。MTT法检测异甘氨酚对鼻咽癌细胞的抗肿瘤作用,流式细胞术,伤口愈合试验，西方印迹,transwell分析，集落形成试验,免疫荧光，和透射电子显微镜（TEM）。在NPC细胞异种移植模型中评估体内抗肿瘤功效。
结果：功能研究显示，异甘醇抑制细胞增殖，菌落形成,鼻咽癌细胞的迁移和侵袭能力。异甘氨酚通过降低线粒体膜电位和ΔWm引起线粒体损伤以过度产生活性氧。与紫杉醇（PTX）相比，异甘氨醇在异种移植肿瘤模型中也基本上抑制了NPC细胞的生长，而没有任何明显的毒性。机理研究表明，异甘氨酚增加Bax/Bcl-2的比例，裂解的caspase-3和细胞质细胞色素C水平诱导线粒体凋亡。异甘氨酚的ROS过量产生可以通过降低p-Akt和Snail的水平来抑制EMT途径。此外，异甘氨酚促进LC3-Ⅰ向LC3-Ⅱ的转化,但是增加p62水平来阻断自噬通量，导致受损线粒体的积累促进NPC细胞的自噬性细胞死亡。
结论：本研究为藤黄的抗肿瘤应用提供了新的理论基础，证实了异甘醇可作为鼻咽癌治疗的候选药物，且毒性低。
