Hydrophobic interaction mediated coating of pluronics on mesoporous silica nanoparticle with stimuli responsiveness for cancer therapy

In this research, a novel method was used to successfully stably coat Pluronic P123 on mesoporous silica nanoparticles (MSNs). Co-constructing a drug delivery system (DDS) with P123 and MSNs has not been previously reported. In this DDS, the coating of P123 was realized through a hydrophobic interaction with octadecyl chain-modified MSNs. The experiments found only Pluronic with an appropriate ratio of hydrophilic and lipophilic segments could keep the nanoassemblies stable. For comparison, nanoassemblies consisting of P123 and octadecyl chain-modified MSNs with or without a disulfide bond were prepared, which were denoted as PSMSNs and PMSNs, respectively. The disulfide bond was expected to endow the system with redox-responsiveness to enhance the therapeutic effect meanwhile decreasing the toxicity. A series of experiments including characterization of the nanoparticles, in vitro drug release, cell uptake and cellular drug release, in vitro cytotoxicity, cell migration and biodistribution of the nanoparticles were carried out. Compared with the PMSNs, PSMSNs displayed a redox-responsive drug release property not only in in vitro release text, but also on the cellular level. In addition, the cell migration experiments proved that the coating of P123 endowed the system with the ability of anti-metastasis. The accumulation of P123 in the tumor was enhanced after coating the MSNs by virtue of the 'EPR' effect of nanoparticles compared with the solution form.

Antitumor and Antimetastasis Activities of Heparin-based Micelle Served As Both Carrier and Drug

Effective treatments for tumors are not easy to achieve due to the existence of metastases, which are responsible for most tumor death. Hence, a new drug delivery system is a pressing need, which should be biocompatible, stimuli-responsive, and multifunctional, including antitumor, antimetastasis, and antiangiogenesis effects. However, it is challenging to achieve all of these properties in one drug delivery system. Here, we developed a system of drug DOX and heparin into one self-assemble nanoparticle via pH-sensitive hydrazone bond and hydrophobic groups, deoxycholate. In the process, heparin itself was not only as the hydrophilic segments of the carrier, but also processed multiple biological functions such as antiangiogenesis and antimetastasis effect. The micelle nanoparticle HD-DOX processed good stability and acidic pH-triggered drug release property. After systemic administration, heparin-based micelle nanoparticle showed longer half-time and enhanced accumulation of DOX in tumors through the enhanced permeability and retention effect, leading to more efficient antitumor effects. In addition, heparin could hinder platelet-induced tumor cells epithelial-mesenchymal transition (EMT) and partially affect cell actin cytoskeletal arrangement, resulting in the disorganization of the actin cytoskeleton. Therefore, HD-DOX exhibited significant inhibitory effect on the metastasis in melanoma animal model in C57BL/6 mouse. Meanwhile, benefited from the antiangiogenesis effect of heparin, tube formations in endothelial cells were effectively inhibited and tumor vascular density was decreased by HD-DOX. Taken together, our study developed a self-assembly nanoplatform that both the drug and carrier had therapeutic effects with ideal antitumor efficacy.