Polyplexes of Functional PAMAM Dendrimer/Apoptin Gene Induce Apoptosis of Human Primary Glioma Cells In Vitro

Abstract

: Highly efficient and safe gene delivery has become an important aspect of neuronal gene therapy. We evaluated the ability of polyamidoamine (PAMAM) dendrimer grafted with phenylalanine, histidine, and arginine (PAMAM-FHR), a nonviral gene delivery vector, to deliver a therapeutic, tumor cell-specific killer gene, apoptin, into the human primary glioma cell line GBL-14 and human dermal fibroblasts. We performed a transfection assay using plasmids of luciferase and enhanced green fluorescent protein (EGFP) and assessed cell viability. Both cell lines were treated with complexes of PAMAM-FHR and apoptin after which their intracellular uptake and localization were examined by fluorescence-activated cell sorting (FACS)analysis and confocal laser scanning microscopy. Confocal microscopy showed that the PAMAM-FHR escaped from the endo-lysosome into the cytosol. Cell cycle phase distribution analysis, annexin V staining, and a tetramethylrhodamine ethyl ester (TMRE) assay established that apoptin triggered apoptosis in the GBL-14 cell line but not in normal fibroblasts. These results indicated that the PAMAM-FHR/apoptin complex is an effective gene vehicle for cancer therapy in vitro.

<p>PAMAM Dendrimer Nanomolecules Utilized as Drug Delivery Systems for Potential Treatment of Glioblastoma: A Systematic Review</p>

“…This was the primary investigational premise of Bae and colleagues (2019) who designed a PAMAM dendrimer with phenylalanine, histidine, and arginine surface modifications (PAMAM-FHR). 60 This construct delivered a tumor cell-specific gene, apoptin, to human primary glioma cell lines (GBL-14) and human dermal fibroblasts in vitro. Apoptin was complexed with PAMAM derivatives and cell lines treated with either PAMAM or PAMAM-FHR dendrimers at increasing doses over 24 and 48 hrs showed negligible toxicity in all cell lines.…”

“…The latter resulted in significantly higher cellular expression of apoptin compared to the former, suggesting that surface modifications with FHR may enhance gene transfer into glioma cells. 60 While surface modifications to PAMAM dendrimers influence the cell-specificity of the dendrimers, they can also enhance cargo delivery. For instance, at Central Michigan University, a G4 PAMAM dendrimer with a cystamine core (D-Cys) with a 90:10 surface ratio of hydroxyl to amine has been developed to encapsulate curcumin (Cur).…”

Apoptin as a Tumor-Specific Therapeutic Agent: Current Perspective on Mechanism of Action and Delivery Systems

“…Beneficial effects on hindlimb function and inhibition of tumor growth have been reported when PAM-RG4 was used to deliver VP3 gene to intramedullary spinal cord tumor in a rat model ( Pennant et al, 2014 ). In addition to mono-amino acid conjugates, di- and tripeptide conjugates of PAMAMs have also been used to effectively deliver Apoptin into human primary glioma cells, human hepatocellular carcinoma cells, and glioblastoma cells ( Bae et al, 2016 , 2017a , b , 2019 ).…”

Cancer Treatment Goes Viral: Using Viral Proteins to Induce Tumour-Specific Cell Death

“…Recently, a novel polyamidoamine dendrimer (PAMAM) was used as a vehicle for apoptin gene delivery to glioma cell lines. These complexes were shown to induce intracellular internalization by endocytosis, and are released from the lysosome resulting in toxicity to glioma cell-lines [161]. Lipid complexes are also useful to deliver DNA.…”