Tumor-Homing Cell-Penetrating Peptide Linked to Colloidal Mesoporous Silica Encapsulated (-)-Epigallocatechin-3-gallate as Drug Delivery System for Breast Cancer Therapy in Vivo

Chemotherapy is the use of chemical drugs to prevent cancer cell proliferation, invasion, and metastasis, but a serious obstacle is that chemotherapeutics strikes not only on cancerous cells, but also on normal cells. Thus, anticancer drugs without side effects should be developed and extracted. (-)-Epigallocatechin-3-gallate (EGCG), a major ingredient of green tea, possesses excellent medicinal values, such as anticancer effects, DNA-protective effects, etc. However, EGCG will be mostly metabolized if it is directly orally ingested. Here, we report a drug delivery system (DDS) for loading EGCG to enhance its stability, promising target and anticancer effects in vitro and in vivo. The designed DDS is composed of three main moieties: anticancer drug, EGCG; drug vector, colloidal mesoporous silica (CMS); target ligand, breast tumor-homing cell-penetrating peptide (PEGA-pVEC peptide). Based on the results of CCK-8 assay, confocal imaging, cell cycle analysis, and Western blot, the anticancer effect of EGCG was increased by loading of EGCG into CMS and CMS@peptide. In vivo treatment displayed that CMS had a not obvious influence on breast tumor bearing mice, but CMS@peptide@EGCG showed the greatest tumor inhibition rate, with about 89.66%. H&E staining of organs showed no tissue injury in all experimental groups. All the above results prove that EGCG is an excellent anticancer drug without side effects and CMS@peptide could greatly promote the efficacy of EGCG on breast tumors by targeted accumulation and release, which provide much evidence for the CMS@peptide as a promising and targeting vector for DDS.