Yadav Amit S, Radharani N Naga Venkata, Gorain Mahadeo, Bulbule Anuradha, Shetti Dattatrya, Roy Gaurab, Baby Thejus, Kundu Gopal C
Laboratory of Tumor Biology, Angiogenesis and Nanomedicine Research, National Centre for Cell Science (NCCS), Pune 411007, India.
Nanoscale. 2020 May 21;12(19):10664-10684. doi: 10.1039/c9nr10673a. Epub 2020 May 6.
Acidic pH is a crucial intrinsic property of the microenvironment of most solid tumors. Hence, the use of pH sensitive tumor targeting nanoparticles is an attractive approach to enhance the therapeutic efficacy of anti-cancer agents in solid tumors. Chitosan nanoparticles (CHNPs) have been widely explored in the area of cancer drug delivery; nevertheless their true potential as a pH responsive targeted drug delivery vehicle in cancer therapy has not been deciphered yet as most of the research is limited to pH dependent stability and drug release. In the present study, we investigate the direct effect of pH in synergy with RGD peptide based targeting on the therapeutic efficacy of chitosan nanoparticles (RGD-CHNPs) in breast cancer. Furthermore, for the first time we performed a comprehensive study showing the anti-tumor, anti-migratory and anti-angiogenic effect of raloxifene (Rlx) loaded CHNPs in breast cancer. We prepared stable formulations of raloxifene encapsulated CHNPs and RGD-CHNPs by the nontoxic ionic gelation method. pH dependent studies revealed that NPs possess higher stability and zeta potential along with enhanced cellular uptake at acidic pH (as present in solid tumors) compared to physiological pH. Furthermore, RGD conjugation enhanced the in vitro cellular uptake of CHNPs in αβ integrin expressing breast cancer cells and induced higher cellular apoptosis in breast cancer cells which was further augmented by lower pH. Moreover, Rlx-RGD-CHNPs significantly inhibited breast cancer cell migration and angiogenesis. In vivo studies showed that Cy5.5 conjugated RGD-CHNPs can distinctly visualize tumors and Rlx-RGD-CHNPs significantly inhibit breast tumor growth without causing any toxic effect to normal tissue as confirmed by hematology and blood biochemical studies. Therefore, RGD-CHNPs could potentially enhance the therapeutic efficacy of chemotherapeutic drugs due to the synergistic effect of pH responsiveness and tumor specific targeting in breast cancer.
酸性pH值是大多数实体瘤微环境的关键内在特性。因此，使用对pH敏感的肿瘤靶向纳米颗粒是增强实体瘤中抗癌药物治疗效果的一种有吸引力的方法。壳聚糖纳米颗粒（CHNPs）在癌症药物递送领域已得到广泛研究；然而，作为癌症治疗中pH响应性靶向药物递送载体，其真正潜力尚未被破解，因为大多数研究仅限于pH依赖性稳定性和药物释放。在本研究中，我们研究了pH与基于RGD肽的靶向协同作用对壳聚糖纳米颗粒（RGD-CHNPs）在乳腺癌治疗效果中的直接影响。此外，我们首次进行了一项全面研究来展示载有雷洛昔芬（Rlx）的CHNPs在乳腺癌中的抗肿瘤、抗迁移和抗血管生成作用。我们通过无毒离子凝胶法制备了包封雷洛昔芬的CHNPs和RGD-CHNPs的稳定制剂。pH依赖性研究表明，与生理pH相比，纳米颗粒在酸性pH（如实体瘤中存在的pH）下具有更高的稳定性和zeta电位，同时细胞摄取增强。此外，RGD偶联增强了表达αβ整合素的乳腺癌细胞中CHNPs的体外细胞摄取，并诱导乳腺癌细胞中更高的细胞凋亡，而较低的pH进一步增强了这种凋亡。此外，Rlx-RGD-CHNPs显著抑制乳腺癌细胞迁移和血管生成。体内研究表明，Cy5.5偶联的RGD-CHNPs可以清晰地可视化肿瘤，并且Rlx-RGD-CHNPs显著抑制乳腺肿瘤生长，血液学和血液生化研究证实对正常组织没有任何毒性作用。因此，由于pH响应性和肿瘤特异性靶向在乳腺癌中的协同作用，RGD-CHNPs可能会增强化疗药物的治疗效果。
