Hydrogel loading functionalized PAMAM/shRNA complex for postsurgical glioblastoma treatment

Area of Science:

• Biomedical Engineering
• Cancer Research
• Immunotherapy

Background:

• Glioblastoma is a highly aggressive brain tumor with frequent postoperative recurrence.
• Tumor cells often evade the immune system through mechanisms like CD47 overexpression.
• Targeting the CD47-SIRPα axis offers a potential strategy to overcome immune suppression.

Purpose of the Study:

• To develop a localized drug delivery system for postoperative glioblastoma treatment.
• To inhibit immune escape of residual glioblastoma cells using a gene complex targeting the CD47-SIRPα axis.
• To evaluate the efficacy of a thermo-sensitive hydrogel loaded with a G5-BGG/shRNA complex in an in vivo glioblastoma model.

Main Methods:

• Synthesis of a novel non-viral vector (G5-BGG) and formation of a gene complex with shRNA targeting CD47.
• Loading of the G5-BGG/pDNA complex into a thermo-sensitive PLGA-PEG-PLGA hydrogel for sustained release.
• In vitro evaluation of CD47 downregulation and macrophage phagocytosis of U87MG cells.
• In vivo assessment of the hydrogel's efficacy in an orthotopic U87MG postoperative tumor model, combined with temozolomide.

Main Results:

• The G5-BGG/shRNA complex effectively downregulated CD47 protein expression in glioblastoma cells.
• Enhanced phagocytosis of tumor cells by macrophages was observed.
• The hydrogel demonstrated sustained release of the gene complex for up to 7 days.
• Combined treatment significantly reduced CD47 expression, increased macrophage infiltration, and prolonged survival in mice.

Conclusions:

• The thermo-sensitive hydrogel loaded with G5-BGG/shRNA represents a promising localized therapy for postoperative glioblastoma.
• This approach effectively overcomes tumor immune escape by targeting the CD47-SIRPα pathway.
• The combination therapy shows significant potential for improving patient outcomes in glioblastoma treatment.