Abstract

Combinatorial photodynamics and chemotherapy have drawn enormous attention as therapeutic modalities via precise stimuli-responsive drug delivery for glioblastoma, which can overcome the limitations associated with conventional therapies. Herein, we have prepared an indocyanine green tagged, genistein encapsulated casein nanoformulation (ICG-Gen@CasNPs) that exhibits the near infra-red region responsive controlled release of genistein and enhanced cellular uptake in the human glioblastoma monolayer and a three-dimensional raft culture model via the enhanced retention effect. ICG-Gen@CasNPs, with the integrated photosensitizer indocyanine green within the nanoformulation, triggered oxidative stress, activating the apoptosis cascade, promoting cell cycle arrest and damaging the mitochondrial membrane potential, collectively directing glioblastoma cell death. The suppression of the polycomb group of proteins in the glioblastoma upon ICG-Gen@CasNPs/NIR exposure revealed the involvement of the epigenetic repression complex machinery in the regulation. Furthermore, ICG-Gen@CasNPs/PDT/PTT directed ubiquitination and proteasomal degradation of EZH2 and BMI1 indicates the implication of the polycomb in conferring glioblastoma survival. The increased activation of the apoptotic pathways and the generation of cellular reactive oxygen species upon inhibiting the expression of EZH2 and BMI1 strengthen our observations. It is worth noting that ICG-Gen@CasNPs robustly accumulated in the brain after crossing the blood–brain barrier, which represents the eminent biocompatibility and means that the system is devoid of any nonspecific toxicity in vivo. Moreover, a superior anti-tumor effect was demonstrated on a three-dimensional glioma spheroid model. Thus, this combinatorial chemo/photodynamic therapy revealed that ICG-Gen@CasNPs mediated epigenetic regulation, which is a crucial molecular mechanism of GBM suppression.

Highlights

  • IntroductionInhibition of the epidermal growth factor receptor (EGF-R) associated tyrosine kinase.[11]

  • Glioblastoma multiforme (GBM) is the most common primary malignant form of brain cancer and is aggressive, highly invasive and vascularized

  • The loading efficiency of the ICGGen@Casein nanoparticles (CasNPs) was 10.2% and the mean hydrodynamic diameter were found to be around 68 Æ 10 nm for the placebo CasNPs, and 93 Æ 7 nm for the indocyanine green (ICG)-Gen@CasNPs respectively, obtained via dynamic light scattering (DLS) with a monodispersed solution phase indicated by the polydispersity index (PDI) of 0.129 Æ 0.10 nm and 0.182 Æ 0.15 nm for the placebo CasNPs and ICGGen@CasNPs, respectively (Fig. 1A)

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Summary

Introduction

Inhibition of the epidermal growth factor receptor (EGF-R) associated tyrosine kinase.[11]. The developed nanoformulation consists of three main components, Cas nanoparticles as a nanocarrier prepared using the desolvation method, Gen as a multitargeted anti-cancerous drug and ICG as a NIR photosensitizer conjugated within. The ability of the ICG-Gen@CasNPs to cross the BBB was evident from the in vitro Transwell assay and the in vivo studies, and they robustly accumulated in the brains of mice They induced negligible non-speci c toxicity and a good biocompatibility. Coefficient of correlation (r2), which was further analyzed using the numerical desirability function and graphical optimization methods.[41]

Reagents
Genistein encapsulation and ICG tagging
Drug loading and drug encapsulation efficiency
In vitro drug release studies
Cell culture
Optimization of NIR light and photothermal experiments in solutions
2.10 Cytotoxicity assay and photodynamic therapy
Cellular uptake studies using confocal laser scanning microscopy
2.11 Measurement of ROS production
2.12 Cell cycle analysis
2.13 Annexin V apoptosis assay
2.15 Real-time quantitative PCR analyses
2.16 Western blot analysis
2.17 Detection of ubiquitinated PcG proteins
2.18 Trans-well model and permeability assay
2.19 In vivo and ex vivo bio-distribution of nanoparticles
2.20 Therapeutic assessment on glioma 3D spheroids
2.21 Statistical analysis
Results and discussion
Drug and nano-carrier interactions and compatibility
In vitro cell cycle and cellular apoptosis analysis
Mitochondrial membrane depolarization and apoptosis analysis
Gene expression pro ling and western blot expression analysis
Trans-well assay and permeability assessment
Conclusions
Full Text
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