Department of Burns and Plastic Surgery, The Second Affiliated Hospital of Shantou University Medical College, Shantou, Guangdong, PR China.
Department of Chemistry, Shantou University Medical College, Shantou, Guangdong, PR China.
Life Sci. 2021 Apr 15;271:119185. doi: 10.1016/j.lfs.2021.119185. Epub 2021 Feb 9.
Melanoma is a malignant tumor of the skin with a high metastasis rate and poor prognosis. Glaucocalyxin A (GLA), isolated from Rabdosia japonica, is a diterpenoid compound with anticancer properties. Here, we investigated the anticancer properties and explored the mechanisms underlying GLA activity in melanoma cells in vitro and in vivo.
Cell Counting Kit-8 and colony formation assays were used to assess the effects of GLA on cell proliferation. Flow cytometry was used to evaluate the cell cycle, apoptosis, mitochondrial membrane potential (MMP), and reactive oxygen species (ROS), and western blot analysis and immunofluorescence staining were used to examine protein expression. Immunohistochemical analysis was performed to examine animal tissues and tumors in mice.
GLA could effectively inhibit cell proliferation and induce cell apoptosis. GLA induced an overproduction of cellular ROS, decreased MMP, and upregulated the Bax/Bcl-2 ratio, which is an indicator of apoptosis. Phosphorylation of nuclear factor κB (NF-κB)/p65 and NF-κB/p65 nuclear expression decreased after GLA treatment in vitro and in vivo, suggesting that the anticancer effects of GLA are mediated through the NF-κB/p65 pathway. Moreover, we observed that GLA was effective in inhibiting tumor growth without obvious toxicity to major organs in mice.
This is the first study to show that GLA inhibits cell proliferation, arrests the cell cycle in the G2/M phase, and induces mitochondrial apoptosis via the NF-κB/p65 pathway in melanoma cells. Overall, our results demonstrate that GLA may be a potential anticancer agent for the treatment of melanoma.
黑色素瘤是一种皮肤恶性肿瘤，具有高转移率和预后不良的特点。从Rabdosia japonica 中分离得到的蓝萼甲素（GLA）是一种具有抗癌特性的二萜化合物。在这里，我们研究了 GLA 在体外和体内对黑色素瘤细胞的抗癌特性和作用机制。
使用细胞计数试剂盒-8 和集落形成实验来评估 GLA 对细胞增殖的影响。流式细胞术用于评估细胞周期、凋亡、线粒体膜电位（MMP）和活性氧（ROS），并使用 Western blot 分析和免疫荧光染色来检测蛋白表达。免疫组织化学分析用于检查动物组织和小鼠肿瘤。
GLA 能有效抑制细胞增殖并诱导细胞凋亡。GLA 诱导细胞内 ROS 过度产生，降低 MMP，并上调凋亡标志物 Bax/Bcl-2 比值。体外和体内实验均表明，GLA 对 NF-κB/p65 的磷酸化及其核表达具有抑制作用，提示 GLA 的抗癌作用是通过 NF-κB/p65 通路介导的。此外，我们观察到 GLA 能有效抑制肿瘤生长，而对小鼠主要器官无明显毒性。
这是首次研究表明 GLA 通过 NF-κB/p65 通路抑制黑色素瘤细胞增殖，将细胞周期阻滞在 G2/M 期，并诱导线粒体凋亡。总的来说，我们的研究结果表明 GLA 可能是一种治疗黑色素瘤的潜在抗癌药物。
