Micro-syringe chip-guided intratumoral administration of lipid nanoparticles for targeted anticancer therapy.

backgroundNano-sized drug delivery system has been widely studied as a potential technique to promote tumor-specific delivery of anticancer drugs due to its passive targeting property, but resulting in very restricted improvements in its systemic administration so far. There is a requirement for a different approach that dramatically increases the targeting efficiency of therapeutic agents at targeted tumor tissues.

methodsTo improve the tumor-specific accumulation of anticancer drugs and minimize their undesirable toxicity to normal tissues, a tumor-implantable micro-syringe chip (MSC) with a drug reservoir is fabricated. As a clinically established delivery system, six liposome nanoparticles (LNPs) with different compositions and surface chemistry are prepared and their physicochemical properties and cellular uptake are examined in vitro. Subsequently, MSC-guided intratumoral administration is studied to identify the most appropriate for the higher tumor targeting efficacy with a uniform intratumoral distribution. For efficient cancer treatment, pro-apoptotic anticancer prodrugs (SMAC-P-FRRG-DOX) are encapsulated to the optimal LNPs (SMAC-P-FRRG-DOX encapsulating LNPs; ApoLNPs), then the ApoLNPs are loaded into the 1 μL-volume drug reservoir of MSC to be delivered intratumorally for 9 h. The tumor accumulation and therapeutic effect of ApoLNPs administered via MSC guidance are evaluated and compared to those of intravenous and intratumoral administration of ApoLNP in 4T1 tumor-bearing mice.

resultsMSC is precisely fabricated to have a 0.5 × 4.5 mm needle and 1 μL-volume drug reservoir to achieve the uniform intratumoral distribution of LNPs in targeted tumor tissues. Six liposome nanoparticles with different compositions of 1-palmitoyl-2-oleoyl-glycero-3-phosphocholine (PC), 1,2-dioleoyl-sn-glycero-3-phospho-L-serine (PS), 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP), and 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[methoxy (polyethylene glycol)

conclusionThe MSC-guided administration of LNPs greatly enhances the therapeutic efficiency of anticancer drugs via the slow diffusion mechanism through micro-syringe to tumor tissues for 6 h, whereas they bypass most hurdles of systemic delivery including hepatic metabolism, rapid renal clearance, and interaction with blood components or other normal tissues, resulting in the minimum toxicity to normal tissues. The negatively charged ApoLNPs with cancer cell-specific pro-apoptotic prodrug (SMAC-P-FRRG-DOX) show the highest tumor-targeting efficacy when they are treated with the MSC guidance, compared to their intravenous or intratumoral administration in 4T1 tumor-bearing mice. The MSC-guided administration of anticancer drug-encapsulated LNPs is expected to be a potent platform system that facilitates overcoming the limitations of systemic drug administration with low delivery efficiency and serious side effects.