Recent cell-based therapy approaches have employed both nanotechnologies and other biomedical technologies to enhance their therapeutic potential. A combined strategy using therapeutic stem/progenitor cells and angiogenic proteins is attractive for the treatment of vascular disease. In this study, we developed an injectable multifunctional micro-sized gel system (microgel), composed of arginine-glycine-aspartic acid (RGD)-conjugated alginate, for the delivery of both cells and growth factors in vivo. The microgels encapsulated with outgrowth endothelial cells (OECs) and growth factors (vascular endothelial growth factor, VEGF, and hepatocyte growth factor, HGF) were formed via electrospraying. Cells encapsulated within the microgel exhibited a time-dependent proliferation with enhanced cell viability, and the size-controlled microgels resulted in sustained release of growth factors for enhanced new vessel formation by tube formation and rat aorta sprouting in vitro. Increased angiogenesis was also estimated in mice treated with RGD-microgel containing OECs and growth factors. Furthermore, injection of the multifunctional microgel into a hindlimb ischemia model improved blood flow perfusion and increased the capillary density by histological analysis. Compared with hydrogel system, injectable microgel system was shown to be superior with no toxicity. Overall, our injectable multifunctional microgel system can be attributed to deliver potential therapeutic agents/cells for the treatment of vascular diseases.

Purpose: Oncolytic adenoviruses (Ad) constitute a new promising modality of cancer gene therapy that displays improved efficacy over nonreplicating Ads. We have previously shown that an E1B 19-kDa-deleted oncolytic Ad exhibits a strong cell-killing effect but lacks tumor selectivity. To achieve hepatoma-restricted cytotoxicity and enhance replication of Ad within the context of tumor microenvironment, we used a modified human a-fetoprotein (hAFP) promoter to control the replication of Ad with a hypoxia response element (HRE).Experimental Design: We constructed Ad-HRE 6 /hAFPD19 and Ad-HRE 12 /hAFPD19 that incorporated either 6 or 12 copies of HRE upstream of promoter. The promoter activity and specificity to hepatoma were examined by luciferase assay and fluorescence-activated cell sorting analysis. In addition, the AFP expression-and hypoxia-dependent in vitro cytotoxicity of Ad-HRE 6 /hAFPD19 and Ad-HRE 12 /hAFPD19 was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and cytopathic effect assay. In vivo tumoricidal activity on subcutaneous and liver orthotopic model was monitored by noninvasive molecular imaging.Results: Ad-HRE 12 /hAFPD19 exhibited enhanced tumor selectivity and cell-killing activity when compared with Ad-hAFPD19. The tumoricidal activity of Ad-HRE 12 /hAFPD19 resulted in significant inhibition of tumor growth in both subcutaneous and orthotopic models. Histologic examination of the primary tumor after treatment confirmed accumulation of viral particles near hypoxic areas. Furthermore, Ad-HRE 12 / hAFPD19 did not cause severe inflammatory immune response and toxicity after systemic injection.Conclusions: The results presented here show the advantages of incorporating HREs into a hAFP promoter-driven oncolytic virus. This system is unique in that it acts in both a tissue-specific and tumor environment-selective manner. The greatly enhanced selectivity and tumoricidal activity of Ad-HRE 12 / hAFPD19 make it a promising therapeutic agent in the treatment of liver cancers.

Mesenchymal stem cells (MSCs) promote therapeutic angiogenesis to cure serious vascular disorders. However, their survival period and cytokine-secretory capacity are limited. Although hepatocyte growth factor (HGF) can accelerate the rate of angiogenesis, recombinant HGF is limited because of its very short half-life (<3–5 minutes). Thus, continuous treatment with HGF is required to obtain an effective therapeutic response. To overcome these limitations, we produced genome-edited MSCs that secreted HGF upon drug-specific induction. The inducible HGF expression cassette was integrated into a safe harbor site in an MSC chromosome using the TALEN system, resulting in the production of TetOn-HGF/human umbilical cord blood-derived (hUCB)-MSCs. Functional assessment of the TetOn-HGF/hUCB-MSCs showed that they had enhanced mobility upon the induction of HGF expression. Moreover, long-term exposure by doxycycline (Dox)-treated TetOn-HGF/hUCB-MSCs enhanced the anti-apoptotic responses of genome-edited MSCs subjected to oxidative stress and improved the tube-formation ability. Furthermore, TetOn-HGF/hUCB-MSCs encapsulated by arginine-glycine-aspartic acid (RGD)-alginate microgel induced to express HGF improved in vivo angiogenesis in a mouse hindlimb ischemia model. This study showed that the inducible HGF-expressing hUCB-MSCs are competent to continuously express and secrete HGF in a controlled manner. Thus, the MSCs that express HGF in an inducible manner are a useful therapeutic modality for the treatment of vascular diseases requiring angiogenesis.