黄酮类化合物具有多种生物学活性，例如抗炎、抗肿瘤、抗血栓等。桑树根皮提取的新型异戊烯基黄酮类化合物—桑梓酚，在先前的研究中已证实具有抗动脉血栓和抗炎作用，但其抗癌机制仍不清楚。本研究主要探讨了桑梓酚在黑色素瘤中的抗肿瘤效应及其作用模式。采用MTT、EdU、克隆形成和软琼脂糖球测定评估桑梓酚对黑色素瘤的抗癌效应。流式细胞术用于检测细胞周期和凋亡。γ-H2AX荧光免疫和碱性彗星实验用于检测DNA损伤，酶联免疫吸附测定用于检测CHK1的泛素化和蛋白质衰减。采用细胞系来源的异种移植（CDX）小鼠模型评估桑梓酚对肿瘤发生性的影响。我们证明桑梓酚不仅具有抑制细胞增殖的能力，还能诱导人类黑色素瘤细胞在G0/G1期停滞、通过caspase依赖性途径诱导凋亡和引起DNA损伤。此外，在体内，桑梓酚能有效抑制黑色素瘤移植瘤的生长。更重要的是，在给予桑梓酚治疗后，在维持细胞周期、基因组稳定性和细胞生存能力方面发挥重要作用的CHK1因子呈剂量和时间依赖性下调，我们进一步探索了桑梓酚通过泛素-蛋白酶体途径对CHK1的降解作用，其结果表明在黑色素瘤细胞系中，过表达CHK1可部分救治在桑梓酚诱导下出现的细胞周期静止、凋亡和DNA损伤等不良反应。此外，我们的进一步研究表明桑梓酚可促进DTIC对黑色素瘤的敏感性，不仅在体外，还在体内均具有显著的治疗效果。我们的研究首次为桑梓酚成为治疗黑色素瘤的候选药物提供了理论基础，可以单独或与DTIC联合使用。版权所有 © 2023 Elsevier GmbH 发布。

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.Copyright © 2023. Published by Elsevier GmbH.