功能化载药脂质体凝胶剂及其对肿瘤干细胞塑性分化实验治疗与机制研究

Relapse of cancer or cancer cell regeneration is related to multi-directional differentiation, and unrestricted proliferation replication potential of cancer stem cells. Surgical operation is unable to remove the residual cancer stem cells in the surrounding tissue of cancer. Furthermore, regular chemotherapy and radiation treatment cannot eliminate cancer stem cells because they exhibit significant multidrug resistance and radiation resistance. Therefore, how to eliminate cancer stem cells by plastic differentiation treatment during killing cancer cells remains to be an important scientific issue. Objectives of the present study are to construct a kind of functional drug liposomes phase transition gel for inducing the plastic differentiations of cancer stem cells to normal body cells, dormant cells, and mature cancer cells. The plastically differentiated normal cells or dormant cells could be incorporated into normal part of body tissue, while the well differentiated cancer cells could be killed by treatment with functional drug liposomes phase transition gel during the same treatment process. Experiments are mainly performed on breast cancer, breast cancer stem cells, and cancer-bearing animal models. The studies consist of four parts as the following: (a) construction and characterization of functional drug liposomes phase transition gel; (b) induction of plastic differentiation of cancer stem cells and the related biomarkers; (c) modulation mechanism and treatment effect in inducing plastic differentiation of cancer stem cells; and (d) overall efficacy in inducing and treating plastic differentiation of cancer stem cells in animals. The predicated outcomes involve the construction of functional drug liposomes phase transition gel, displaying the signaling transduction pathways and the related biomarkers, and providing the evidence for inducing effect and treatment efficacy in vitro cancer cells and in cancer-bearing animals xenografted with breast cancer stem cells. This study would offer theoretical basis and experimental evidence for inducing plastic differentiation of cancer stem cells, and propose a new strategy for cancer therapy.

科学问题：肿瘤治疗后复发与肿瘤干细胞的多向性分化、无限制增殖复制潜能有关。如何在杀伤肿瘤细胞的同时、对肿瘤干细胞进行塑性分化治疗、防止肿瘤治疗后反弹与复发是亟待解决的重要科学问题。研究目标：本项目提出，构建一种功能化载药脂质体相变型凝胶剂，对肿瘤干细胞进行塑性分化实验治疗，使其塑性分化为正常细胞、周期阻滞性“休眠”细胞和成熟肿瘤细胞。对于塑性分化的体细胞或休眠细胞，可成为机体组织的一部分，而对于塑性分化的成熟肿瘤细胞，予以治疗杀伤。方法与内容：本研究以乳腺癌、乳腺癌干细胞以及荷瘤动物为主要研究对象展开，包括制剂的构建与表征、体外塑性分化效应及标志物研究、塑性分化机制及体外治疗效应研究、在动物体内验证。预期结果：构建一种全新的功能化载药脂质体相变型凝胶剂，可对肿瘤干细胞进行塑性分化治疗，阐明塑性分化效应的机制、信号通路与标志物，为揭示肿瘤干细胞塑性分化治疗提供理论依据和奠定实验基础。

研究背景：肿瘤治疗后复发与肿瘤干细胞的多向性分化、无限制增殖复制潜能有关。在杀伤肿瘤细胞的同时、对肿瘤干细胞进行塑性分化治疗、可望防止肿瘤治疗后反弹与复发。研究目标：构建一种功能化载药脂质体制剂，对肿瘤干细胞进行塑性分化实验治疗，使其塑性分化为正常细胞、周期阻滞性“休眠”细胞和成熟肿瘤细胞。主要内容：（1）功能化载药脂质体制剂的构建与表征；（2）对肿瘤干细胞塑性分化的诱导效应及特征性标志物研究；（3）对肿瘤干细胞的塑性分化调控机制；（4）体外对肿瘤干细胞分化治疗效应研究；（5）在动物体内对肿瘤干细胞分化治疗效应研究。重要结果：以乳腺癌、乳腺癌干细胞以及荷瘤动物为主要研究对象，验证提出的肿瘤干细胞塑性分化策略，并进一步利用盐碱霉素及其新构建的功能性脂质体来实现这一策略。全基因、肿瘤干细胞mRNA和蛋白表达分析表明，盐碱霉素可诱导肿瘤干细胞进入正常细胞（JUN上调）、休眠细胞/成熟癌细胞（标志物FOS、SLUG、Twist1和PKC α下调）。该结果与PKCα信号通路的抑制机制有关。分化的正常或休眠细胞被纳入正常组织，而其余的细胞被化疗杀死。科学意义：本研究为肿瘤干细胞的塑性分化奠定了理论基础、提供了实验证据，并揭示了一种肿瘤塑性分化治疗新策略。