洛伐他汀通过核仁应激介导的自噬抑制三阴性乳腺癌干细胞作用的分子机制

三阴性乳腺癌是临床最难治的乳腺癌亚型。肿瘤干细胞是肿瘤耐药、转移和复发的根源。我们近期研究发现用于治疗高脂血症的天然化合物洛伐他汀（LV）在体内外能够选择性抑制三阴性乳腺癌干细胞的干性特征并促进其自噬性细胞死亡。进一步通过翻译后修饰组学研究发现LV导致三阴性乳腺癌干细胞中蛋白质赖氨酸巴豆酰化的改变，其主要集中于两条与应激相关的通路，即核仁应激和自噬；WB分析发现LV使核仁应激相关关键蛋白p14ARF显著上调。我们提出LV可能通过ARF诱导的核仁应激促进自噬，从而抑制三阴性乳腺癌干细胞的干性特征。本项目拟研究：1）LV诱导三阴性乳腺癌干细胞中核仁应激的分子机制；2）LV诱导三阴性乳腺癌干细胞自噬的分子机制；3）敲低ARF能否逆转LV在体外及体内对三阴性乳腺癌干细胞的抑制作用。本项目的实施将进一步阐明LV抑制三阴性乳腺癌干细胞的分子机制，为将LV推向临床用于乳腺癌的精准治疗提供坚实的理论依据。

Triple-negative breast cancer (TNBC) is the most difficult-to-treat breast cancer subtype. Cancer stem cells (CSCs) play a major role in drug resistance, metastasis and recurrence. Our preliminary studies have demonstrated that the natural compound lovastatin (LV), which has been used in the clinic as a lipid-lowering drug, could selectively inhibit the stemness properties and trigger autophagic cell death in TNBC over non-TNBC CSCs. Furthermore, global lysine crotonylation profiling revealed that LV could induce the alterations of lysine crotonylation on proteins involved in two stress-related pathways, i.e., nucleolar stress and autophagy, in TNBC CSCs. Western blot analysis showed that LV obviously upregulated p14ARF, a tumor suppressor and a key nucleolar stress-related protein. We hypothesize that LV can inhibit the stemness properties of TNBC CSCs through upregulation of p14ARF, which leads to nucleolar stress and autophagy. In this project, we will study: 1) the mechanisms how LV induces nucleolar stress in TNBC CSCs; 2) the mechanism how LV induces autophagy in TNBC CSCs; 3) whether knockdown of p14ARF reverses the effect of LV on TNBC CSCs in vitro and in vivo. Implementation of this project will further clarify the molecular mechanisms of the inhibitory effects of LV on TNBC, and lay the foundation for repurposing of LV as an anti-TNBC drug.