Cell-based Delivery Research Articles

Emerging therapies for Parkinsonʼs disease

The experimental therapeutics of Parkinson's disease are reviewed, highlighting the current pipeline of emerging therapeutic approaches. This review includes novel approaches to dopaminergic drug delivery such as intraintestinal infusions or new extended-release formulations of levodopa and also intrapulmonary delivery of apomorphine as well as novel dopaminergic agents like the monoamine oxidase-B inhibitor safinamide or novel catechol-O-methyl transferase inhibitors. An even greater number of ongoing clinical trials assess the efficacy and safety of nondopaminergic approaches to enhance motor control or reduce motor complications like fluctuations and dyskinesias. These include adenosine A2A antagonists, α-adrenergic and serotonergic agonists as well as drugs acting on the glutamatergic system. Gene-based or cell-based intrastriatal delivery of therapeutic principles that enhance striatal dopaminergic transmission directly or via the stimulation of trophic activity has also reached phase II clinical development with encouraging results in some studies. Finally, a wide spectrum of agents with a potential for slowing disease progression is currently tested. A variety of medical and nonmedical interventions in different phases of clinical development provide an interesting and promising portfolio of emerging therapies for Parkinson's disease.

Stem cell-based delivery of brain-derived neurotrophic factor gene in the rat retina

As an alternative to a viral vector, the application of stem cells to transfer specific genes is under investigation in various organs. Using this strategy may provide more effective method to supply neurotrophic factor to the neurodegenerative diseases caused by neurotrophic factor deprivation. This study investigated the possibility and efficacy of stem cell-based delivery of the brain-derived neurotrophic factor (BDNF) gene to rat retina. Rat BDNF cDNA was transduced into rat bone marrow mesenchymal stem cells (rMSCs) using a retroviral vector. Its incorporation into the experimental rat retina and the expression of BDNF after intravitreal injection or subretinal injection were detected by real-time PCR, western blot analysis, and immunohistochemical staining. For the incorporated rMSCs, retinal-specific marker staining was performed to investigate the changes in morphology and the characteristics of the stem cells. Transduction of the rMSCs by retrovirus was effective, and the transduced rMSCs expressed high levels of the BDNF gene and protein. The subretinal injection of rMSCs produced rMSC migration and incorporation into the rat retina (about 15.7% incorporation rate), and retinal BDNF mRNA and protein expression was increased at 4 weeks after transplantation. When subretinal injection of rMSCs was applied to axotomized rat retina, it significantly increased the expression of BDNF until 4 weeks after transplantation. Some of the transplanted rMSCs exhibited morphological changes, but the retinal-specific marker stain was not sufficient to indicate whether neuronal differentiation had occurred. Using mesenchymal stem cells to deliver the BDNF gene to the retina may provide new treatment for glaucoma.

Blood-Borne Macrophage–Neural Cell Interactions Hitchhike on Endosome Networks for Cell-Based Nanozyme Brain Delivery

Macrophage-carried nanoformulated catalase ('nanozyme') attenuates neuroinflammation and protects nigrostriatal neurons from 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine intoxication. This is facilitated by effective enzyme transfer from blood-borne macrophages to adjacent endothelial cells and neurons leading to the decomposition of reactive oxygen species. We examined the intra- and inter-cellular trafficking mechanisms of nanozymes by confocal microscopy. Improved neuronal survival mediated by nanozyme-loaded macrophages was demonstrated by fluorescence-activated cell sorting. In macrophages, nanozymes were internalized mainly by clathrin-mediated endocytosis then trafficked to recycling endosomes. The enzyme is subsequently released in exosomes facilitated by bridging conduits. Nanozyme transfer from macrophages to adjacent cells by endocytosis-independent mechanisms diffusing broadly throughout the recipient cells. In contrast, macrophage-free nanozymes were localized in lysosomes following endocytic entry. Facilitated transfer of nanozyme from cell to cell can improve neuroprotection against oxidative stress commonly seen during neurodegenerative disease processes.

Stem cell-based delivery of Hypoxamir-210 to the infarcted heart: implications on stem cell survival and preservation of infarcted heart function

This study seeks to test our hypothesis that transgenic induction of miR-210 in mesenchymal stem cells (MSC) simulates the pro-survival effects of ischemic preconditioning (IPC) and that engraftment of (PC)MSC helps in the functional recovery of ischemic heart by miR-210 transfer to host cardiomyocytes through gap junctions. miR-210 expression in MSC was achieved by IPC or nanoparticle-based transfection of miR-210 plasmid ((miR)MSC) and functional recovery of the infarcted heart of rat transplanted with (PC)MSC or (miR)MSC was evaluated. Both (PC)MSC and (miR)MSC showed higher survival under lethal anoxia as compared to (non-PC)MSC and scramble-transfected MSC ((Sc)MSC) controls with concomitantly lower CASP8AP2 expression. Similarly, both (PC)MSC and (miR)MSC survived better and accelerated functional recovery of ischemic heart post-transplantation. To validate our hypothesis that MSC deliver miR-210 to host cardiomyocytes, in vitro co-culture between cardiomyocytes and (PC)MSC or (miR)MSC (using (non-PC)MSC or (Sc)MSC as controls) showed co-localization of miR-210 with gap-junctional connexin-43. miR-210 transfer to cardiomyocytes was blocked by heptanol pretreatment. Moreover, higher survival of cardiomyocytes co-cultured with (PC)MSC was observed with concomitant expression of CASP8AP2 as compared to cardiomyocytes co-cultured with (non-PC)MSC thus suggesting that miR-210 was translocated from MSC to protect host cardiomyocytes. Induction of miR-210 in MSC promoted their survival post-engraftment in the infarcted heart. Moreover, direct transfer of pro-survival miR-210 from (miR)MSC to host cardiomyocytes led to functional recovery of the ischemic heart.

Confocal Imaging of Trans‐epithelial Trafficking by Immune and Umbilical Cord Stem Cells in the Neonatal Porcine Intestine

Maternal colostral leucocytes (CL) and peripheral blood mononuclear cells (PBMC) enter the neonatal circulation after ingestion in pigs and cattle. Porcine umbilical cord matrix stem cells (PUCs) are relatively non-immunogenic after initial allogeneic transplantation. Using intestinal explant cultures incubated with labelled cells and confocal microscopy, we demonstrated trans-epithelial trafficking of exogenous CL, PBMC and PUCs below the luminal surface after 72 h of culture. We orally administered PBMC and PUCs to pre-colostral neonatal pigs and tracked their location 8 or 24 h later. Both PBMC and PUCs were found in the intestinal wall of all samples. Exposure to 25% of acellular colostrum had no detected effect on trafficking. Labelled PUCs and PBMC were detected on the surface of the epithelium and in the lamina propria 8 h post-treatment and PBMC were also in the superficial submucosa. At 24 h, PUCs and PBMC were observed on the surface of the epithelium, in the lamina propria, superficial submucosa and deep submucosa. Our findings show the potential of PUCs for allogeneic engraftment in the neonatal intestine and may lead to cell-based delivery of therapeutics.

Advances in Treatment and Management: Immunologic and Cell-Based Regenerative Therapies

The glaucomas are a group of eye diseases characterized by progressive ganglion cell and optic nerve damage, leading to constriction of the visual fields and eventual loss of central vision. Although the disease is typically associated with increased intraocular pressure (IOP), there are patients with low- or normal-tension glaucoma and others with elevated IOP who do not experience optic nerve damage. The ocular pathology observed in glaucoma can affect the trabecular meshwork (TM; the main outflow tract for intraocular fluid), the ganglion cell layer of the retina, and the optic nerve head and associated lamina cribrosa. Therapies for these diseases have largely been directed at lowering IOP through pharmacologically decreasing aqueous humor production in the ciliary body or increasing outflow by targeting the TM with drugs or surgical intervention. Although these approaches can lead to significant lowering of the IOP, most patients still experience progressive visual loss, albeit at a slower rate than occurs if the high pressure is left untreated. More recently, efforts have been directed at providing neuroprotection for the cells primarily responsible for vision loss, the retinal ganglion cells (RGCs). Recent advances in stem cell biology, regenerative medicine, and cell-based therapies provide the opportunity to protect or replace cells damaged by increased IOP or other less well-understood abnormalities associated with glaucoma. In this article, I review recent advances in the areas of stem cell biology and cell-based delivery of neuroprotectants for the treatment of retinal diseases and discuss their potential applications for the treatment of glaucoma. I also review recent advances in metabolomics and transcriptomics that will enable analysis of factors that may be present in patients who have increased IOP but no damage from glaucoma.

Stable release of BDNF from the fibroblast cell line NIH3T3 grown on silicone elastomers enhances survival of spiral ganglion cells in vitro and in vivo

The treatment of choice for profound sensorineural hearing loss (SNHL) is direct electrical stimulation of spiral ganglion cells (SGC) via a cochlear implant (CI). The number and excitability of SGC seem to be critical for the success that can be achieved via CI treatment. However, SNHL is associated with degeneration of SGC. Long-term drug delivery to the inner ear for improving SGC survival may be achieved by functionalisation of CI electrodes with cells providing growth factors. Therefore, the capacity of brain-derived neurotrophic factor (BDNF)-secreting NIH3T3 cells grown on cylindrically shaped silicone elastomers (SE) to exert local and sustained neuroprotective effects was assessed in vitro and in vivo. An in vitro model to investigate adhesion and cell growth of lentivirally modified NIH3T3 cells synthesising BDNF on SE was established. The bioactivity of BDNF was characterised by co-cultivation of SGC with cell-coated SE. In addition, cell-coated SE were implanted into deafened guinea pigs.The recombinant NIH3T3 cells proliferated on silicone surfaces during 14 days of cultivation and expressed significantly increasing BDNF levels. Enhanced survival rates and neurite outgrowth of SGC demonstrated the bioactivity of BDNF in vitro. Implantation of SE with adhering BDNF-secreting NIH3T3 cells into the cochleae of systemically deafened guinea pigs induced a significant increase in SGC survival in comparison to SE without cell coating. Our data demonstrate a novel approach of cell-based long-term drug delivery to support SGC survival in vitro and in vivo. This therapeutic strategy – once transferred to cells suitable for clinical application – may improve CI performance.

Microfluidic-Based Synthesis of Hydrogel Particles for Cell Microencapsulation and Cell-Based Drug Delivery

Encapsulation of cells in hydrogel particles has been demonstrated as an effective approach to deliver therapeutic agents. The properties of hydrogel particles, such as the chemical composition, size, porosity, and number of cells per particle, affect cellular functions and consequently play important roles for the cell-based drug delivery. Microfluidics has shown unparalleled advantages for the synthesis of polymer particles and been utilized to produce hydrogel particles with a well-defined size, shape and morphology. Most importantly, during the encapsulation process, microfluidics can control the number of cells per particle and the overall encapsulation efficiency. Therefore, microfluidics is becoming the powerful approach for cell microencapsulation and construction of cell-based drug delivery systems. In this article, I summarize and discuss microfluidic approaches that have been developed recently for the synthesis of hydrogel particles and encapsulation of cells. I will start by classifying different types of hydrogel material, including natural biopolymers and synthetic polymers that are used for cell encapsulation, and then focus on the current status and challenges of microfluidic-based approaches. Finally, applications of cell-containing hydrogel particles for cell-based drug delivery, particularly for cancer therapy, are discussed.

Vitamin D3-Inducible Mesenchymal Stem Cell-Based Delivery of Conditionally Replicating Adenoviruses Effectively Targets Renal Cell Carcinoma and Inhibits Tumor Growth

Cell-based carriers were recently exploited as a tumor-targeting tool to improve systemic delivery of oncolytic viruses for cancer therapy. However, the slow clearance of carrier cells from normal organs indicates the need for a controllable system which allows viral delivery only when the carrier cells reach the tumor site. In this study, we sought to develop a pharmaceutically inducible cell-based oncolytic adenovirus delivery strategy for effective targeting and treatment of renal cell carcinoma (RCC), which is one of the most malignant tumor types with an unfavorable prognosis. Herein, we demonstrated the intrinsic tumor homing property of human bone marrow-derived mesenchymal stem cells (hMSCs) to specifically localize primary and metastatic RCC tumors after systemic administration in a clinically relevant orthotopic animal model. The platelet derived growth factor AA (PDGF-AA) secreted from RCC was identified as a chemoattractant responsible for the recruitment of hMSCs. Like endogenous osteocalcin whose barely detectable level of expression was dramatically induced by vitamin D(3), the silenced replication of human osteocalcin promoter-directed Ad-hOC-E1 oncolytic adenoviruses loaded in hMSCs was rapidly activated, and the released oncolytic adenoviruses sequentially killed cocultured RCC cells upon vitamin D(3) exposure. Moreover, the systemic treatment of RCC tumor-bearing mice with hMSC cell carriers loaded with Ad-hOC-E1 had very limited effects on tumor growth, but the loaded hMSCs combined with vitamin D(3) treatment induced effective viral delivery to RCC tumors and significant tumor regression. Therapeutic effects of hMSC-based Ad-hOC-E1 delivery were confirmed to be significantly greater than those of injection of carrier-free Ad-hOC-E1. Our results presented the first preclinical demonstration of a novel controllable cell-based gene delivery strategy that combines the advantages of tumor tropism and vitamin D(3)-regulatable human osteocalcin promoter-directed gene expression of hMSCs to improve oncolytic virotherapy for advanced RCC.

Abstract 5661: Pharmaceutically controlled replication of adenoviruses in mesenchymal stem cell-based cell carriers improves oncolytic virotherapy for advanced human renal cell carcinoma

Abstract Cell-based carriers were recently exploited as a tumor-targeting tool to improve systemic delivery of oncolytic viruses for cancer therapy. However, the slow clearance of carrier cells from normal organs indicates the need for a controllable system which allows viral delivery only when the carrier cells reach the tumor site. In this communication, we sought to develop a pharmaceutically-inducible cell-based oncolytic adenovirus delivery strategy for effective targeting and treatment of renal cell carcinoma (RCC), which is one of the most malignant tumor types with an unfavorable prognosis. Herein, we demonstrated the intrinsic tumor homing property of human bone marrow-derived mesenchymal stem cells (hMSCs) to specifically localize primary and metastatic RCC tumors after systemic administration in a clinically relevant orthotopic animal model. PDGF-AA secreted from RCC was identified as a chemoattractant responsible for the recruitment of hMSCs. Like endogenous osteocalcin whose barely detectable level of expression was dramatically induced by vitamin D3, the silenced replication of human osteocalcin promoter-directed Ad-hOC-E1 oncolytic adenoviruses loaded in hMSCs was rapidly activated and the released viral progenies sequentially killed co-cultured RCC cells upon vitamin D3 exposure. Moreover, systemic treatment of RCC tumor-bearing mice with Ad-hOC-E1-loaded hMSCs had very limited effect on tumor growth, but when it combined with vitamin D3 treatment induced effective viral delivery to RCC tumors and significant tumor regression. Therapeutic effects of hMSC-based Ad-hOC-E1 delivery were confirmed to be significantly greater than those of injection of carrier-free Ad-hOC-E1. Our results presented the first pre-clinical demonstration of a novel controllable cell-based gene delivery strategy that combines the advantages of tumor tropism and vitamin D3-regulatable human osteocalcin promoter-directed gene expression of hMSCs to improve oncolytic virotherapy for advanced RCC. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 5661. doi:1538-7445.AM2012-5661

Cells Take up and Recover from Protein-Stabilized Single-Wall Carbon Nanotubes with Two Distinct Rates

Single-wall carbon nanotubes (SWCNTs) are increasingly being investigated for use in biomedical applications for intracellular imaging and ablation, as well as vehicles for drug and gene delivery. One major obstacle to the development of safe, controlled, and effective SWCNT-based biomedical materials is limited quantification of dosage- and time-dependent uptake kinetics, cellular effects, and recovery profiles. Here, we quantified NIH-3T3 cellular uptake of and recovery from individualized SWCNTs dispersed using a biocompatible dispersing agent, bovine serum albumin (BSA). Uptake and recovery were determined by monitoring the mass of SWCNTs-BSA per cell, as a function of SWCNTs-BSA over the concentration range of 1 to 100 μg mL(-1) and time range of seconds to days. To determine SWCNTs-BSA biocompatibility as a function of uptake and recovery, cytotoxicity, proliferation potential, and cell phenotype were monitored for each condition. Interestingly, the rate of cellular uptake of SWCNTs-BSA was rapid, reaching steady state within ∼1 min, in agreement with modeling. We also observed a threshold SWCNT exposure level (>1 μg mL(-1)) above which internalization is saturated and uptake scales linearly with exposure amount. Cells were able to recover from SWCNTs-BSA over ∼30 h, regardless of dosage level or exposure time. We suggest that these differential rates of uptake and recovery, quantified in our work, may enable cell-based SWCNT delivery systems.

Monitoring the glioma tropism of bone marrow-derived progenitor cells by 2-photon laser scanning microscopy and positron emission tomography

Intracerebral experimental gliomas attract intravenously injected murine or human bone marrow-derived hematopoietic progenitor and stem cells (HPC) in vitro, ex vivo, and in vivo, indicating that these progenitor cells might be suitable vehicles for a cell-based delivery of therapeutic molecules to malignant gliomas. With regard to therapeutic application, it is important to investigate cell fates in vivo (i.e., the time-dependent intratumoral and systemic distribution after intravenously injection). Conventional histological analysis has limitations in this regard because longitudinal monitoring is precluded. Here, we used 2-photon laser scanning microscopy (2PLSM), positron emission tomography (PET), and MRI to study the fate of intravenously injected HPC carrying fluorescence, bioluminescence, and PET reporter genes in glioma-bearing mice. Our 2PLSM-based monitoring studies revealed that HPC homing to intracerebral experimental gliomas occurred already within the first 6 h and was most efficient within the first 24 h after intravenous injection. The highest PET signals were detected in intracerebral gliomas, whereas the tracer uptake in other organs, notably spleen, lung, liver, and muscle, remained at background levels. The results have important implications for designing schedules for therapeutic cell-based anti-glioma approaches. Moreover, the PET reporter-based imaging technique will allow noninvasive monitoring of cell fate in future cell-based therapeutic antiglioma approaches.

Sol–gel immobilized ovarian follicles: collaboration between two different cell types in hormone production and secretion

The immobilization of mammalian cells within semipermeable matrices which allow retention of viability and functionality has recently attracted research interest. In this study, rat mature ovarian follicles were encapsulated in sol–gel silica matrices for the evaluation of in vitro steroid hormones production. Tetraethoxysilane (TEOS) and tetrakis(2-hydroxyethyl)orthosilicate (THEOS) were evaluated for cell viability, progesterone and estradiol secretion and cell structure conservation. Significant differences were observed between TEOS and THEOS, which allowed encapsulation of follicles for 9 days. Although encapsulated follicles showed lower viability and proliferation rates than control follicles, they were able to secrete estradiol to the same extent as control follicles. This study demonstrated an effective collaboration between two different mammalian cell types in hormone production and secretion when encapsulated in silica matrices. These results could lead to the development of ovarian cell-based hormone delivery systems for the treatment of the symptoms of menopause and the Turner syndrome minimizing adverse effects.

Blood-borne macrophage-neural cell interactions hitchhike on endosome networks for cell-based nanozyme brain delivery

Blood-borne macrophage-neural cell interactions hitchhike on endosome networks for cell-based nanozyme brain delivery

Feline Neural Progenitor Cells II: Use of Novel Plasmid Vector and Hybrid Promoter to Drive Expression of Glial Cell Line-Derived Neurotrophic Factor Transgene

Sustained transgene expression is required for the success of cell transplant-based gene therapy. Most widely used are lentiviral-based vectors which integrate into the host genome and thereby maintain sustained transgene expression. This requires integration into the nuclear genome, and potential risks include activation of oncogenes and inactivation of tumor suppressor genes. Plasmids have been used; however lack of sustained expression presents an additional challenge. Here we used the pCAG-PyF101-eGFP plasmid to deliver the human GDNF gene to cat neural progenitor cells (cNPCs). This vector consists of a CAGG composite promoter linked to the polyoma virus mutant enhancer PyF101. Expression of an episomal eGFP reporter and GDNF transgene were stably maintained by the cells, even following induction of differentiation. These genetically modified cells appear suitable for use in allogeneic models of cell-based delivery of GDNF in the cat and may find veterinary applications should such strategies prove clinically beneficial.

Stem cells as therapeutic vehicles for the treatment of high-grade gliomas

Stem cells have generated great interest in the past decade as potential tools for cell-based treatment of human high-grade gliomas. Thus far, 3 types of stem cells have been tested as vehicles for various therapeutic agents: embryonic, neural, and mesenchymal. The types of therapeutic approaches and/or agents examined in the context of stem cell-based delivery include cytokines, enzyme/prodrug suicide combinations, viral particles, matrix metalloproteinases, and antibodies. Each strategy has specific advantages and disadvantages. Irrespective of the source and/or type of stem cell, there are several areas of concern for their translation to the clinical setting, such as migration in the adult human brain, potential teratogenesis, immune rejection, and regulatory and ethical issues. Nonetheless, a clinical trial is under way using neural stem cell-based delivery of an enzyme/prodrug suicide combination for recurrent high-grade glioma. A proposed future direction could encompass the use of stem cells as vehicles for delivery of agents targeting glioma stem cells, which have been implicated in the resistance of high-grade glioma to treatment. Overall, stem cells are providing an unprecedented opportunity for cell-based approaches in the treatment of high-grade gliomas, which have a persistently dismal prognosis and mandate a continued search for therapeutic options.

Cell-based delivery of oncolytic viruses

Oncolytic viruses,a novel class of virus vectors,which selectively replicate only in tumor cells,have excellent tumor targeting and good tansfection efficiency.Many oncolytic viruses have apparent curative effect when administered intratumorally.However,the host immune system remains a critical obstacle to systemic administration of virotherapeutics.It appears that cell-based delivery of oncolytic viruses could offer one solution to this critical problem,which provides a new platform to the biological therapy of cancer. Key words: Oncolytic viruses ; Neoplasms ; Therapy ;

Macrophages as Cell-Based Delivery Systems for Nanoshells in Photothermal Therapy

Site-specific delivery of nanoparticles poses a significant challenge, especially in the brain where the blood-brain barrier prevents the entry of most therapeutic compounds including nanoparticle-based anti-cancer agents. In this context, the use of macrophages as vectors for the delivery of gold-silica nanoshells to infiltrating gliomas will be reviewed in this article. Gold-silica nanoshells are readily phagocytosed by macrophages without any apparent toxic effects, and the results of in vitro studies have demonstrated the migratory potential of nanoshell-loaded macrophages in human glioma spheroids. Of particular interest is the observation that, after near-infrared exposure of spheroids containing nanoshell-loaded macrophages, sufficient heat was generated to suppress spheroid growth. Collectively, these findings demonstrate the potential of macrophages as nanoshell delivery vectors for photothermal therapy of gliomas, and they certainly provide the basis for future animal studies.

Manipulating piggyBac Transposon Chromosomal Integration Site Selection in Human Cells

The ability to direct gene delivery to a user-defined chromosomal location would greatly improve gene transfer applications. The piggyBac transposon system is a nonviral gene transfer system proven effective in a variety of cells and tissues, including human cells. We fused a highly site-specific synthetic zinc-finger DNA-binding domain (ZFP) to the N-terminus of the piggyBac transposase and evaluated site-directed genomic integration in human cells. Chimeric ZFP-piggyBac transposase exhibited robust gene transfer activity, targeted binding to a cognate endogenous chromosomal ZFP site in the human genome, and site-directed transposon integration into an episomal plasmid target containing a single ZFP site in human cells. We evaluated the ability of ZFP-piggyBac to direct gene integration into an engineered chromosomal ZFP target site in the human genome and consistently observed a higher degree of ZFP-piggyBac site-directed genomic integration when compared to native piggyBac. Chromatin immunoprecipitation (ChIP) experiments revealed binding of native piggyBac to our engineered TTAA-containing chromosomal target which supported integration, but not a TTAA-deficient chromosomal target which lacked integration. Our results offer insight into the requirements for using a chimeric zinc finger-piggyBac transposase to direct integration into a user-defined chromosomal location.

Anti-tumor effects of canine adipose tissue-derived mesenchymal stromal cell-based interferon-β gene therapy and cisplatin in a mouse melanoma model

Adipose tissue (AT)-derived mesenchymal stromal cells (MSC) (AT-MSC) represent a novel tool for delivering therapeutic genes to tumor cells. Interferon (IFN)-β is a cytokine with pleiotropic cellular functions, including anti-proliferative, immunomodulatory and anti-angiogenic activities. The purpose of this study was to engineer canine AT-MSC (cAT-MSC) producing IFN-β and to evaluate the anti-tumor effect of cAT-MSC-IFN-β combined with cisplatin in mouse melanoma model. cAT-MSC engineered to express mouse IFN-β were generated using a lentiviral vector (cAT-MSC-IFN-β) and the secreted IFN-β-induced inhibition of tumor cell growth and apoptosis on B16F10 cells was investigated in vitro prior to in vivo studies. Melanoma-bearing mouse was developed by injecting B16F10 cells subcutaneously into 6-week-old C57BL/6 mice. After 14 days, cisplatin (10 mg/kg) was injected intratumorally, and 3 days later the engineered cAT-MSC were injected subcutaneously every 3 days to death. Tumor volume and survival times were measured. The combination treatment of cAT-MSC-IFN-β with cisplatin was more effective in inhibiting the growth of melanoma and resulted in significantly extended survival time than both an unengineered cAT-MSC-cisplatin combination group and a cisplatin-alone group. Interestingly, subcutaneously injected cAT-MSC-IFN-β were migrated to tumor sites. Our data suggest that canine AT-MSC could serve as a powerful cell-based delivery vehicle for releasing therapeutic proteins to tumor lesions. Maximal anti-tumor effects were seen when this therapy was combined with a DNA-damaging chemotherapeutic agent. This study demonstrates the possible applicability of AT-MSC-mediated IFN-β in treating canine and human cancer patients.