背景:桦木酸(BA)对各种癌症的抗增殖和线粒体途径介导的凋亡诱导作用已得到充分研究。然而,其溶解性差和脱靶活性限制了其在临床试验中的应用。此外,桦木酸类似物在肿瘤微环境(TME)中的免疫调节作用尚不清楚.这里,我们设计了一种潜在的纳米治疗结直肠癌(CRC)与白杨酸铅类似物,命名为2c,携带通过接头连接到BA的1,2,3-三唑部分,发现比BA更有效地抑制CRC细胞系,被选到这里进行调查.上皮细胞粘附分子(EpCAM)在CRC细胞膜上高度过表达。单链短寡核苷酸序列,适体(Apt),折叠成3D定义的结构可以用作靶向配体,用于其与靶蛋白的特异性结合。EpCAM靶向适体被设计用于在CRC肿瘤位点处的适体缀合的加载2c的纳米颗粒(Apt-2cNP)的位点特异性归巢,以增强治疗潜力并减少正常细胞中的脱靶毒性。我们研究了适体偶联纳米疗法在CRC-TME中的体外和体内治疗功效和抗肿瘤免疫反应。
方法:经过表征的纳米工程适体结合桦木酸纳米疗法,我们评估了治疗效果,肿瘤靶向效率,以及使用基于细胞的测定和小鼠和大鼠模型的抗肿瘤免疫应答。
结果:我们发现Apt-2cNP提高了药物的生物利用度,延长了它的生物半衰期,提高抗增殖活性,和最小化的脱靶细胞毒性。重要的是,在体内TME中,Apt-2cNP显示抗肿瘤免疫反应的有希望的迹象(mDC/pDC比值增加,增强的M1巨噬细胞群,和CD8T细胞)。此外,体内促凋亡的上调而抗凋亡基因的下调以及对癌组织病理学的显着治愈功效表明,Apt-2cNP比非适体缀合的纳米颗粒和游离药物具有更大的治疗潜力。此外,我们在CRC大鼠模型中通过实时成像观察到放射性标记的Apt-2cNP的肿瘤积累更大。
结论:Apt-2cNP在CRC-TME中增强的治疗效果和强大的抗肿瘤免疫反应是其作为治疗CRC的潜在潜在治疗药物的有希望的指标。然而,需要进一步的研究。
BACKGROUND: Betulinic acid (BA) has been well investigated for its antiproliferative and mitochondrial pathway-mediated apoptosis-inducing effects on various cancers. However, its poor solubility and off-target activity have limited its utility in clinical trials. Additionally, the immune modulatory role of betulinic acid analogue in the tumor microenvironment (TME) is largely unknown. Here, we designed a potential nanotherapy for colorectal cancer (CRC) with a lead betulinic acid analogue, named as 2c, carrying a 1,2,3-triazole-moiety attached to BA through a linker, found more effective than BA for inhibiting CRC cell lines, and was chosen here for this investigation. Epithelial cell adhesion molecule (EpCAM) is highly overexpressed on the CRC cell membrane. A single-stranded short oligonucleotide sequence, aptamer (Apt), that folds into a 3D-defined architecture can be used as a targeting ligand for its specific binding to a target protein. EpCAM targeting aptamer was designed for site-specific homing of aptamer-conjugated-2c-loaded nanoparticles (Apt-2cNP) at the CRC tumor site to enhance therapeutic potential and reduce off-target toxicity in normal cells. We investigated the in vitro and in vivo therapeutic efficacy and anti-tumorigenic immune response of aptamer conjugated nanotherapy in CRC-TME.
METHODS: After the characterization of nanoengineered aptamer conjugated betulinic acid nanotherapy, we evaluated therapeutic efficacy, tumor targeting efficiency, and anti-tumorigenic immune response using cell-based assays and mouse and rat models.
RESULTS: We found that Apt-2cNP improved drug bioavailability, enhanced its biological half-life, improved antiproliferative activity, and minimized off-target cytotoxicity. Importantly, in an in vivo TME, Apt-2cNP showed promising signs of anti-tumorigenic immune response (increased mDC/pDC ratio, enhanced M1 macrophage population, and CD8 T-cells). Furthermore, in vivo upregulation of pro-apoptotic while downregulation of anti-apoptotic genes and significant healing efficacy on cancer tissue histopathology suggest that Apt-2cNP had predominantly greater therapeutic potential than the non-aptamer-conjugated nanoparticles and free drug. Moreover, we observed greater tumor accumulation of the radiolabeled Apt-2cNP by live imaging in the CRC rat model.
CONCLUSIONS: Enhanced therapeutic efficacy and robust anti-tumorigenic immune response of Apt-2cNP in the CRC-TME are promising indicators of its potential as a prospective therapeutic agent for managing CRC. However, further studies are warranted.