Department of Dermatology, The Third Hospital of Hebei Medical University, 050000, No.139 Ziqiang Road, Qiaoxi District, Shijiazhuang, Hebei 050051, China; State Key Laboratory of Resource Insects, Key Laboratory of Luminescent and Real-Time Analytical Chemistry (Ministry of Education), Southwest University, Chongqing 400716, China.
State Key Laboratory of Resource Insects, Key Laboratory of Luminescent and Real-Time Analytical Chemistry (Ministry of Education), Southwest University, Chongqing 400716, China; Hospital of Southwest University, Medical Research Institute, Southwest University, Chongqing 400716, China; Engineering Research Center for Cancer Biomedical and Translational Medicine, Southwest University, Beibei, Chongqing 400716, China; Chongqing Engineering and Technology Research Center for Silk Biomaterials and Regenerative Medicine, Southwest University, Beibei, Chongqing 400716, China.
Phytomedicine. 2023 Jun;114:154765. doi: 10.1016/j.phymed.2023.154765. Epub 2023 Mar 16.
Flavonoids have a variety of biological activities, such as anti-inflammation, anti-tumor, anti-thrombosis and so on. Morusinol, as a novel isoprene flavonoid extracted from Morus alba root barks, has the effects of anti-arterial thrombosis and anti-inflammatory in previous studies. However, the anti-cancer mechanism of morusinol remains unclear.
In present study, we mainly studied the anti-tumor effect of morusinol and its mode of action in melanoma.
The anti-cancer effect of morusinol on melanoma were evaluated by using the MTT, EdU, plate clone formation and soft agar assay. Flow cytometry was used for detecting cell cycle and apoptosis. The ɣ-H2AX immunofluorescence and the alkaline comet assay were used to detect DNA damage and the Western blotting analysis was used to investigate the expressions of DNA-damage related proteins. Ubiquitination and turnover of CHK1 were also detected by using the immunoprecipitation assay. The cell line-derived xenograft (CDX) mouse models were used in vivo to evaluate the effect of morusinol on tumorigenicity.
We demonstrated that morusinol not only had the ability to inhibit cell proliferation, but also induced cell cycle arrest at G0/G1 phase, caspase-dependent apoptosis and DNA damage in human melanoma cells. In addition, morusinol effectively inhibited the growth of melanoma xenografts in vivo. More strikingly, CHK1, which played an important role in maintaining the integrity of cell cycle, genomic stability and cell viability, was down-regulated in a dose- and time-dependent manner after morusinol treatment. Further research showed that CHK1 was degraded by the ubiquitin-proteasome pathway. Whereafter, morusinol-induced cell cycle arrest, apoptosis and DNA damage were partially salvaged by overexpressing CHK1 in melanoma cell lines. Herein, further experiments demonstrated that morusinol increased the sensitivity of dacarbazine (DTIC) to chemotherapy for melanoma in vitro and in vivo.
Morusinol induces CHK1 degradation through the ubiquitin-proteasome pathway, thereby inducing cell cycle arrest, apoptosis and DNA damage response in melanoma. Our study firstly provided a theoretical basis for morusinol to be a candidate drug for clinical treatment of cancer, such as melanoma, alone or combinated with dacarbazine.
类黄酮具有多种生物活性，如抗炎、抗肿瘤、抗血栓等。毛蕊异黄酮作为一种从桑树根皮中提取的新型异戊烯类黄酮，在先前的研究中具有抗动脉血栓形成和抗炎作用。然而，毛蕊异黄酮的抗癌机制尚不清楚。
本研究主要研究毛蕊异黄酮对黑色素瘤的抗肿瘤作用及其作用机制。
采用 MTT、EdU、平板克隆形成和软琼脂实验评价毛蕊异黄酮对黑色素瘤的抗癌作用。流式细胞术检测细胞周期和凋亡。用 γ-H2AX 免疫荧光和碱性彗星实验检测 DNA 损伤，用 Western blot 分析检测 DNA 损伤相关蛋白的表达。用免疫沉淀实验检测 CHK1 的泛素化和周转。用细胞系衍生的异种移植（CDX）小鼠模型在体内评价毛蕊异黄酮对肿瘤发生的影响。
我们证明毛蕊异黄酮不仅具有抑制细胞增殖的能力，而且还能诱导人黑色素瘤细胞周期停滞在 G0/G1 期，caspase 依赖性凋亡和 DNA 损伤。此外，毛蕊异黄酮在体内有效抑制黑色素瘤异种移植瘤的生长。更引人注目的是，CHK1 在维持细胞周期完整性、基因组稳定性和细胞活力方面发挥着重要作用，在毛蕊异黄酮处理后，其表达呈剂量和时间依赖性下调。进一步的研究表明，CHK1 通过泛素-蛋白酶体途径降解。随后，在黑色素瘤细胞系中过表达 CHK1 可部分挽救毛蕊异黄酮诱导的细胞周期阻滞、凋亡和 DNA 损伤。在此基础上，进一步的实验表明，毛蕊异黄酮在体外和体内增加了达卡巴嗪（DTIC）对黑色素瘤的化疗敏感性。
毛蕊异黄酮通过泛素-蛋白酶体途径诱导 CHK1 降解，从而诱导黑色素瘤细胞周期停滞、凋亡和 DNA 损伤反应。本研究首次为毛蕊异黄酮作为一种候选药物，单独或与达卡巴嗪联合用于临床治疗癌症（如黑色素瘤）提供了理论依据。
