Bufalin-loaded mPEG-PLGA-PLL-cRGD nanoparticles: preparation, cellular uptake, tissue distribution, and anticancer activity

Peihao Yin,^1,* Yan Wang,^1,* YanYan Qiu,¹ LiLi Hou,¹ Xuan Liu,¹ Jianmin Qin,¹ Yourong Duan,² Peifeng Liu,² Ming Qiu,³ Qi Li<sup>1

1</sup>Department of Clinical Oncology, Putuo Hospital and Interventional Cancer Institute of Integrative Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, China; ²Shanghai Cancer Institute, Jiaotong University, Shanghai, China; ³Department of General Surgery, Changzheng Hospital, Second Military Medical University, Shanghai, China

^*These authors contributed equally to this work

Background: Recent studies have shown that bufalin has a good antitumor effect but has high toxicity, poor water solubility, a short half-life, a narrow therapeutic window, and a toxic dose that is close to the therapeutic dose, which all limit its clinical application. This study aimed to determine the targeting efficacy of nanoparticles (NPs) made of methoxy polyethylene glycol (mPEG), polylactic-co-glycolic acid (PLGA), poly-L-lysine (PLL), and cyclic arginine-glycine-aspartic acid (cRGD) loaded with bufalin, ie, bufalin-loaded mPEG-PLGA-PLL-cRGD nanoparticles (BNPs), in SW620 colon cancer-bearing mice.
Methods: BNPs showed uniform size. The size, shape, zeta potential, drug loading, encapsulation efficiency, and release of these nanoparticles were studied in vitro. The tumor targeting, cellular uptake, and growth-inhibitory effect of BNPs in vivo were tested.
Results: BNPs were of uniform size with an average particle size of 164 ± 84 nm and zeta potential of 2.77 mV. The encapsulation efficiency was 81.7% ± 0.89%, and the drug load was 3.92% ± 0.16%. The results of in vitro cytotoxicity studies showed that although the blank NPs were nontoxic, they enhanced the cytotoxicity of bufalin in BNPs. Drug release experiments showed that the release of the drug was prolonged and sustained. The results of confocal laser scanning microscopy indicated that BNPs could effectively bind to human umbilical vein endothelial cells. In the SW620 xenograft mice model, the BNPs could effectively target the tumor in vivo. The BNPs were significantly more effective than other NPs in preventing tumor growth.
Conclusion: BNPs had even size distribution, were stable, and had a slow-releasing and tumor-targeting effect. BNPs significantly inhibited colon cancer growth in vitro and in vivo. As a novel drug carrier system, BNPs are a potentially promising targeting treatment for colon cancer.

Keywords: colon cancer, nanoparticles, tumor target, bufalin