Gene Therapy for Drug-Resistant Glioblastoma via Lipid-Polymer Hybrid Nanoparticles Combined with Focused Ultrasound.

Background: Therapy for glioblastoma (GBM) has always been very challenging, not only because of the presence of the blood-brain barrier (BBB) but also due to susceptibility to drug resistance. Recently, the clustered regularly interspaced short palindromic repeats (CRISPR)-associated protein 9 (CRISPR/Cas9) has revolutionized gene editing technology and is capable of treating a variety of genetic diseases, including human tumors, but there is a lack of safe and effective targeting delivery systems in vivo, especially in the central nervous system (CNS).

Methods: Lipid-polymer hybrid nanoparticles (LPHNs-cRGD) were constructed for efficient and targeting delivery of CRISPR/Cas9 plasmids targeting O6-methylguanine-DNA methyltransferase (MGMT), a drug-resistance gene to temozolomide (TMZ). Focused ultrasound (FUS)-microbubbles (MBs) were used to non-invasively and locally open the BBB to further facilitate gene delivery into glioblastoma in vivo. The gene editing efficiency and drug sensitivity changes were evaluated both in vitro and in vivo.

Results: The gene-loaded LPHNs-cRGD were successfully synthesized and could protect pCas9/MGMT from enzyme degradation. LPHNs-cRGD could target GBM cells and mediate the transfection of pCas9/MGMT to downregulate the expression of MGMT, resulting in an increased sensitivity of GBM cells to TMZ. MBs-LPHNs-cRGD complexes could safely and locally increase the permeability of the BBB with FUS irradiation in vivo and facilitated the accumulation of nanoparticles at the tumor region in orthotopic tumor-bearing mice. Furthermore, the FUS-assisted MBs-LPHNs-cRGD enhanced the therapeutic effects of TMZ in glioblastoma, inhibited tumor growth, and prolonged survival of tumor-bearing mice, with a high level of biosafety.

Conclusion: In this work, we constructed LPHNs-cRGD for targeting delivery of the CRISPR/Cas9 system, in combination with FUS-MBs to open the BBB. The MBs-LPHNs-cRGD delivery system could be a potential alternative for efficient targeting gene delivery for the treatment of glioblastoma.