Doxorubicin-loaded Cholesterol-Glycopolymer Nanomicelles with Autophagy Activator Rapamycin for Synergistic Glioblastoma Cell Inhibition

In a recent work, we developed a pH-responsive diblock glycopolymer (PMAgala₁₈-b-P(MAA₂₄-co-MAChol₆) for the controllable delivery of doxorubicin (DOX); the glycopolymer nanomicelles have high DOX loading efficiency, caveolae-/clathrin-mediated endocytosis pathways, endosome-lysosome localization, and pH-responsive DOX release properties in the Human Glioblastoma Carcinoma (H4) cell line. Herein, we prepared the DOX-loaded glycopolymer micelles. The physico-chemical properties of these DOX-loaded micelles, including particle size, polydispersity (PDI), surface zeta potential, drug loading content (DLC, wt.％), drug loading efficiency (DLE, wt.％), number of loaded DOX , and relative colloidal stability (%), were investigated. In the cell biological study, we utilized the H4 and H4-GFP-LC3 cell lines (stably over-expresses green fluorescent protein (GFP)-tagged microtubule-associated autophagy marker protein 1 light chain 3 (LC3)) as model cell lines. The co-incubation/co-delivery of MAgala₁₈-b-P(MAA₂₄-co-MAChol₆)/DOX nanomicelles with autophagy activator rapamycin (RAPA) could lead to an obviously enhanced tumor cell proliferation inhibitory effect, which might be due to thesynergistic effect of DOX (the Topoisomerase II inhibition and DNA intercalation) and RAPA (autophagy process activation and LC3-II protein degradation). The synergistic effect of MAgala₁₈-b-P(MAA₂₄-co-MAChol₆)/DOX nanomicelles and RAPA was further quantified by Bliss independence analysis. This work showed a preliminary study on the glycopolymer-based (DOX-RAPA) drug co-delivery nanosystem, which might inspire the future development of “anticancer agent-autophagy regulator co-delivery nanotherapeutics” toward clinical cancer chemotherapy.