Suicide gene therapy by canine mesenchymal stem cell transduced with thymidine kinase in a u-87 glioblastoma murine model: Secretory profile and antitumor activity

Abstract

The role played by certain domestic species such as dogs as a translational model in comparative oncology shows great interest to develop new therapeutic strategies in brain tumors. Gliomas are a therapeutic challenge that represents the most common form of malignant primary brain tumors in humans and the second most common form in dogs. Gene-directed enzyme/prodrug therapy using adipose mesenchymal stem cells (Ad-MSCs) expressing the herpes simplex virus thymidine kinase (TK) has proven to be a promising alternative in glioblastoma therapy, through its capacity to migrate and home to the tumor and delivering local cytotoxicity avoiding other systemic administration. In this study, we demonstrate the possibility for canine Ad-MSCs (cAd-MSCs) to be genetically engineered efficiently with a lentiviral vector to express TK (TK-cAd-MSCs) and in combination with ganciclovir (GCV) prodrug demonstrated its potential antitumor efficacy in vitro and in vivo in a mice model with the human glioblastoma cell line U87. TK-cAd-MSCs maintained cell proliferation, karyotype stability, and MSCs phenotype. Genetic modification significantly affects its secretory profile, both the analyzed soluble factors and exosomes. TK-cAd-MSCs showed a high secretory profile of some active antitumor immune response cytokines and a threefold increase in the amount of secreted exosomes, with changes in their protein cargo. We also found that the prodrug protein is not released directly into the culture medium by TK-cAd-MSCs. We believe that our work provides new perspectives for glioblastoma gene therapy in dogs and a better understanding of this therapy in view of its possible implantation in humans.

Suicide gene therapy using allogeneic adipose tissue-derived mesenchymal stem cell gene delivery vehicles in recurrent glioblastoma multiforme: a first-in-human, dose-escalation, phase I clinical trial

“…In addition, based on MR images, in comparison with the baseline, both CET and FLAIR volumes showed a substantial reduction at 6- and 12-months postoperatively. This long-term response observed in patients with recurrent GBM might be attributable to the cytotoxic effects of suicide gene therapy using ADSC gene vehicles similar to preclinical results indicating the role of “bystander effect” in this therapeutic strategy using ADSCs [ 7 , 8 ]. Besides, there are both preclinical and clinical reports showing that in addition to the “bystander effect,” anti-tumor local immune response with infiltration of T cells and NK cells could also be another mechanism involved in suicide gene therapy [ 15 , 22 , 28 – 30 ].…”

“…Further, according to prior findings, stem cells could exert immunomodulatory effects inside the tumor niche [ 5 ]. Thus, regarding the best stem cell type for gene therapy in GBM, one of the best options is mesenchymal stem cell (MSC) based on prior studies [ 6 – 8 ]. MSCs are poorly immunogenic and could be easily obtained from several sources.…”

“…MSCs are poorly immunogenic and could be easily obtained from several sources. Adipose tissue-derived MSCs (ADSCs), in particular, could be a potentially suitable carrier for gene therapy in GBM given their high abundance and ease of isolation in addition to all the aforementioned capabilities [ 6 – 8 ]. Additionally, preclinical studies have suggested a significant cytotoxic efficacy for suicide gene therapy using ADSCs expressing herpes simplex virus thymidine kinase (HSV-TK) gene in animal models of GBM [ 7 – 11 ].…”

New insights in application of mesenchymal stem cells therapy in tumor microenvironment: pros and cons

“…A group of researchers showed that canine adipose MSCs can be treated with a lentiviral vector to express TK. Combined with ganciclovir, this prodrug exerted antitumor effects on human glioblastoma cell line U87 in a murine model ( Villatoro et al, 2022 ). Adipose SCs were also genetically modified to express recombinant secretory human carboxylesterase-2 and nanoluciferase genes.…”