Li Mei, Chen Cailong, Wang Qian, Jiang Xiaolu, Tan Lanlan, Huang Ying, Zhang Yan, Zhang Zubin
Institute of Pediatric Research, Children's Hospital of Soochow University, Suzhou, 215025, China.
Children Health Management Center, Children's Hospital of Soochow University, Suzhou, 215025, China.
Cancer Cell Int. 2021 Dec 19;21(1):683. doi: 10.1186/s12935-021-02375-z.
Multiple myeloma (MM) is the most common malignant hematological disease in the people worldwide. Glaucocalyxin A (GLA) is a bioactive ent-kauranoid diterpenoid, that is derived from Rabdosia japonica var. GLA has been demonstrated that it had various pharmacological activities, such as anti-coagulation, anti-bacterial, anti-tumor, anti-inflammation, antioxidant activities. Although GLA has effective anti-tumor properties, its effects on multiple myeloma remain unclear. The aim of this study was to examine the possible anti-cancer effects of GLA and their molecular mechanisms on MM cells in vitro and in vivo.
To evaluate the role of GLA on the proliferation of MM cells in vitro and in vivo, we used MTT method to detect the role of GLA on the proliferation of MM cells. Cell apoptosis and cell cycle assay were evaluated by flow cytometry. Protein expressions in GLA-treated and untreated MM cells were evaluated by western blot analyses. MM xenograft nude mice model was used to investigate the role of GLA on the proliferation of MM cells in vivo. IHC assay was used to examine the role of GLA on the MM xenograft model in vivo.
In the present study, we firstly reported the potent anti-myeloma activity of GLA on MM cells. We found that GLA could induce apoptosis in vitro and in vivo. GLA could inhibit the phosphorylation of the signal transducer and activator of transcription 3 (STAT3) and downregulate interleukin IL-6 induced STAT3 phosphorylation in MM. Overexpression of STAT3 could significantly prevent apoptosis induced by GLA; while knockdown of STAT3 enhanced it. Moreover, GLA could inhibit cell proliferation by inducing the cell cycle arrest. GLA reduced the expression of cell cycle-related proteins CCNB1, CCND1, CCND2, and CCND3 and increased the expression of p21 in MM cell lines. In addition, in the MM xenograft nude mice model, GLA exhibited very good anti-myeloma activity. Administration of GLA almost completely inhibited tumor growth within 19 days without physical toxicity. And the IHC results showed GLA significantly inhibited cell proliferation and interfered STAT3 pathway on MM xenograft model tumor tissues.
Taken together, our present research indicated that GLA inhibits the MM cell proliferation, induces MM cell apoptosis and cell cycle arrest through blocking the activation of STAT3 pathway. Thus, GLA may be a potential therapeutic candidate for MM patients in the future.
多发性骨髓瘤（MM）是全球最常见的恶性血液病。毛萼甲素（GLA）是一种具有生物活性的对映贝壳杉烷型二萜类化合物，来源于日本香茶菜。已证实GLA具有多种药理活性，如抗凝、抗菌、抗肿瘤、抗炎、抗氧化活性。尽管GLA具有有效的抗肿瘤特性，但其对多发性骨髓瘤的作用仍不清楚。本研究的目的是在体外和体内研究GLA对MM细胞可能的抗癌作用及其分子机制。
为了评估GLA在体外和体内对MM细胞增殖的作用，我们采用MTT法检测GLA对MM细胞增殖的作用。通过流式细胞术评估细胞凋亡和细胞周期。通过蛋白质印迹分析评估GLA处理和未处理的MM细胞中的蛋白质表达。利用MM异种移植裸鼠模型研究GLA在体内对MM细胞增殖的作用。免疫组化分析用于检测GLA在体内对MM异种移植模型的作用。
在本研究中，我们首次报道了GLA对MM细胞具有强大的抗骨髓瘤活性。我们发现GLA能在体外和体内诱导细胞凋亡。GLA可抑制信号转导和转录激活因子3（STAT3）的磷酸化，并下调白细胞介素IL-6诱导的MM中STAT3的磷酸化。STAT3的过表达可显著阻止GLA诱导的细胞凋亡；而敲低STAT3则增强细胞凋亡。此外，GLA可通过诱导细胞周期停滞来抑制细胞增殖。GLA降低了MM细胞系中细胞周期相关蛋白CCNB1、CCND1、CCND2和CCND3的表达，并增加了p21的表达。此外，在MM异种移植裸鼠模型中，GLA表现出非常好的抗骨髓瘤活性。给予GLA在19天内几乎完全抑制肿瘤生长且无身体毒性。免疫组化结果显示GLA显著抑制MM异种移植模型肿瘤组织中的细胞增殖并干扰STAT3通路。
综上所述，我们目前的研究表明GLA通过阻断STAT3通路的激活来抑制MM细胞增殖，诱导MM细胞凋亡和细胞周期停滞。因此，GLA未来可能是MM患者的潜在治疗候选药物。
