Engineering Of Mesenchymal Stem Cells Research Articles

Apoptotic vesicles rescue impaired mesenchymal stem cells and their therapeutic capacity for osteoporosis by restoring miR-145a-5p deficiency.

Apoptotic vesicles (apoVs) play a vital role in various pathological conditions; however, we have yet to fully understand their precise biological effects in rescuing impaired mesenchymal stem cells (MSCs) and regulating tissue homeostasis. Here, we proved that systemic infusion of bone marrow MSCs derived from wild-type (WT) mice effectively improved the osteopenia phenotype and hyperimmune state in ovariectomized (OVX) mice. Importantly, the WT MSCs rescued the impairment of OVX MSCs both in vivo and in vitro, whereas OVX MSCs did not show the same efficacy. Interestingly, treatment with apoVs derived from WT MSCs (WT apoVs) restored the impaired biological function of OVX MSCs and their ability to improve osteoporosis. This effect was not observed with OVX MSCs-derived apoVs (OVX apoVs) treatment. Mechanistically, the reduced miR-145a-5p expression hindered the osteogenic differentiation and immunomodulatory capacity of OVX MSCs by affecting the TGF-β/Smad 2/3-Wnt/β-catenin signaling axis, resulting in the development of osteoporosis. WT apoVs directly transferred miR-145a-5p to OVX MSCs, which were then reused to restore their impaired biological functions. Conversely, treatment with OVX apoVs did not produce significant effects due to their limited expression of miR-145a-5p. Overall, our findings unveil the remarkable potential of apoVs in rescuing the biological function and therapeutic capability of MSCs derived from individuals with diseases. This discovery offers a new avenue for exploring apoVs-based MSC engineering and expands the application scope of stem cell therapy, contributing to the maintenance of bone homeostasis through a previously unrecognized mechanism.

Therapeutic potential and impact of nanoengineered patient‐derived mesenchymal stem cells in a murine resection and recurrence model of human glioblastoma

AbstractConfounding results of engineered mesenchymal stem cells (MSCs) used as cellular vehicles has plagued technologies whereby success or failure of novel approaches may be dismissed or inaccurately ascribed solely to the biotechnology platform rather than suitability of the human donor. Polymeric materials were screened for non‐viral engineering of MSCs from multiple human donors to deliver bone morphogenic protein‐4 (BMP4), a protein previously investigated in clinical trials for glioblastoma (GBM) to combat a subpopulation of highly invasive and tumorigenic clones. A “smart technology” that target the migratory and stem‐like nature of GBM will require: (1) a cellular vehicle (MSC) which can scavenge and target residual cells left behind after surgical debulking and deliver; (2) anti‐glioma cargo (BMP4). Multiple MSC donors are safely engineered, though varied in susceptibility to accept BMP4 due to intrinsic characteristics revealed by their molecular signatures. Efficiency is compared via secretion, downstream signaling, differentiation, and anti‐proliferative properties across all donors. In a clinically relevant resection and recurrence model of patient‐derived human GBM, we demonstrate that nanoengineered MSCs are not “donor agnostic” and efficacy is influenced by the inherent suitability of the MSC to the cargo. Therefore, donor profiles hold greater influence in determining downstream outcomes than the technical capabilities of the engineering technology.

Update on the Use of Mesenchymal Stem Cells and their Products in Hematopoietic Stem Cell Transplantation

Graft Versus Host Disease (GVHD) is a major limitation to the success of allogeneic Hematopoietic Stem Cell Transplantation (HSCT) as Steroid-Refractory (SR) acute GVHD carries poor prognosis due to the absence of an efficacious second-line therapy. Mesenchymal Stem Cells (MSCs) which have immunosuppressive, immunomodulatory, and regenerative properties may become a highly effective therapeutic modality for SR-GVHD in the near future. MSCs have already been approved to treat childhood SR-GVHD in Japan, and they have been conditionally licensed in New Zealand and Canada. It is expected that MSCs will be approved for the treatment of SR-GVHD in adults in Europe, North America, and other parts of the world within a few years. Utilization of the recently introduced techniques including the use of MSC products such as exosomes and Extracellular Vesicles (ECVs) instead of the parent MSCs, robotic manufacturing technology, and genetic engineering of MSCs will ultimately overcome the remaining obstacles facing the widespread utilization of MSCs and their products as therapeutics not only in HSCT but also in other medical fields. The aim of this review is to provide an update on the remarkable progress achieved in the use of MSCs and their products in the field of HSCT.

Mesenchymal stem cell engineering by ARCA analog-capped mRNA

We previously have shown that mRNA-based engineering may enhance mesenchymal stem cell (MSC) trafficking. However, optimal conditions for invitro mRNA engineering of MSCs are unknown. Here, we investigated several independent variables: (1) transfection factor (Lipofectamine 2000 vs. TransIT), (2) mRNA purification method (spin column vs. high-performance liquid chromatography [HPLC] column), and (3) mRNA capping (ARCA vs. β-S-ARCA D1 and β-S-ARCA D2). Dependent variables included protein production based on mRNA template (measured by the bioluminescence of reporter gene luciferase over hours), MSC metabolic activity corresponding with their wellbeing measured by CCK-8 over days, and endogenous expression of genes by RT-qPCR related to innate intracellular immune response and decapping at two time points: days 2 and 5. We have found that Lipofectamine 2000 outperforms TransIT, and used it throughout the study. Then, we showed that mRNA must be purified by HPLC to be relatively neutral to MSCs in terms of metabolic activity and endogenous protein production. Ultimately, we demonstrated that β-S-ARCA D1 enables higher protein production but at the cost of lower MSC metabolic activity, with no impact on RT-qPCR results. Thus Lipofectamine 2000-based invitro transfection of HPLC-purified and ARCA- or β-S-ARCA D1-capped mRNA is optimal for MSC engineering.

Tumor tropic delivery of FU.FA@NSs using mesenchymal stem cells for synergistic chemo-photodynamic therapy of colorectal cancer

To overcome the limitations associated with the targeting abilities of nanotherapeutics and drug loading capacity of mesenchymal stem cells (MSCs), the present study relies on the combination of MSCs tumor tropism with the controlled release function of nano-based drug delivery platforms to achieve tumor-specific accumulation of chemotherapeutics with minimal off-target effects. 5-fluorouracil (5-FU)-containing ceria (CeNPs) coated calcium carbonate nanoparticles (CaNPs) were functionalized with folinic acid (FA) to develop drug-containing nanocomposites (Ca.FU.Ce.FA NCs). NCs were then conjugated with graphene oxide (GO) and decorated with silver nanoparticles (Ag°NPs) to form FU.FA@NS, a rationally designed drug delivery system with O2 generation capacity that alleviates tumor hypoxia for improved photodynamic therapy. Engineering of MSCs with FU.FA@NSs provided successful loading and long-term retention of therapeutics on the surface membrane with minimal changes to the functional properties of MSCs. Co-culturing of FU.FA@NS.MSCs with CT26 cells upon UVA exposure revealed enhanced apoptosis in tumor cells through ROS-mediated mitochondrial pathway. FU.FA@NSs released from MSCs were effectively taken up by CT26 cells via a clathrin-mediated endocytosis pathway and distributed their drug depots in a pH, H2O2, and UVA-stimulated fashion. Therefore, the cell-based biomimetic drug delivery platform formulated in the current study could be considered a promising strategy for targeted chemo-photodynamic therapy of colorectal cancer.

MMP13-Overexpressing Mesenchymal Stem Cells Enhance Bone Tissue Formation in the Presence of Collagen Hydrogel.

Matrix metalloproteinases (MMPs) are proteins involved in the repair and remodeling the extracellular matrix (ECM). MMP13 is essential for bone development and healing through the remodeling of type I collagen (COL1), the main component of the ECM in bone tissue. Mesenchymal stem cells (MSCs)-based cell therapy has been considered a promising approach for bone regeneration because of their osteogenic properties. However, the approaches using MSC to completely regenerate bone tissue have been limited. To overcome the limitation, genetic engineering of MSC could be a strategy for promoting regeneration efficacy. We performed in vitro and in vivo experiments using MMP13-overexpressing MSCs in the presence of COL1. To examine MMP13-overexpressing MSCs in vivo, we prepared a fibrin/COL1-based hydrogel to encapsulate MSCs and subcutaneously implanted gel-encapsulated MSCs in nude mice. We found that the osteogenic marker genes, ALP and RUNX2, were upregulated in MMP13-overexpressing MSCs through p38 phosphorylation. In addition, MMP13 overexpression in MSCs stimulated the expression of integrin α3, which is up-stream receptor of p38, and substantially increased osteogenic differentiation potential of MSCs. Bone tissue formation in MMP13-overexpressing MSCs was significantly higher than that in control MSCs. Taken together, our findings demonstrate that MMP13 is not only an essential factor for bone development and bone healing but also has a pivotal role in promoting osteogenic differentiation of MSCs to induce bone formation. MSCs Genetically engineered to overexpress MMP13, which have a powerful potential to differentiate into the osteogenic cells, might be beneficial in bone disease therapy.

Functional Au nanoparticles for engineering and long-term CT imaging tracking of mesenchymal stem cells in idiopathic pulmonary fibrosis treatment

Idiopathic pulmonary fibrosis (IPF) therapy has always been a big and long-standing challenge in clinical practice due to the lack of miraculous medicine. Mesenchymal stem cells (MSCs)-based therapy has recently emerged as a promising candidate for redefining IPF therapy. Enhancing the therapeutic efficacy of MSCs and understanding of their growth, migration and differentiation in harsh lung microenviroments are two keys to improving the stem cell-based IPF treatment. Herein, a non-viral dual-functional nanocarrier is fabricated by a one-pot approach, using protamine sulfate stabilized Au nanoparticles (AuPS), to genetically engineer MSCs for simultaneous IPF treatment and monitoring the biological behavior of the MSCs. AuPS exhibits superior cellular uptake ability, which results in efficient genetic engineering of MSCs to overexpress hepatocyte growth factor for enhanced IPF therapy. In parallel, the intracellular accumulation of AuPS improves the CT imaging contrast of MSCs, allowing visual tracking of the therapeutic engineered MSCs up to 48 days. Overall, this work has described for the first time a novel strategy for enhanced therapeutic efficacy and long-term CT imaging tracking of transplanted MSCs in IPF therapy, providing great prospect for stem cell therapy of lung disease.

Stem Cell Mimicking Nanoencapsulation for Targeting Arthritis.

Mesenchymal stem cells (MSCs) are considered a promising regenerative therapy due to their ability to migrate toward damaged tissues. The homing ability of MSCs is unique compared with that of non-migrating cells and MSCs are considered promising therapeutic vectors for targeting major cells in many pathophysiological sites. MSCs have many advantages in the treatment of malignant diseases, particularly rheumatoid arthritis (RA). RA is a representative autoimmune disease that primarily affects joints, and secreted chemokines in the joints are well recognized by MSCs following their migration to the joints. Furthermore, MSCs can regulate the inflammatory process and repair damaged cells in the joints. However, the functionality and migration ability of MSCs injected in vivo still show insufficient. The targeting ability and migration efficiency of MSCs can be enhanced by genetic engineering or modification, eg, overexpressing chemokine receptors or migration-related genes, thus maximizing their therapeutic effect. However, there are concerns about genetic changes due to the increased probability of oncogenesis resulting from genome integration of the viral vector, and thus, clinical application is limited. Furthermore, it is suspected that administering MSCs can promote tumor growth and metastasis in xenograft and orthotopic models. For this reason, MSC mimicking nanoencapsulations are an alternative strategy that does not involve using MSCs or bioengineered MSCs. MSC mimicking nanoencapsulations consist of MSC membrane-coated nanoparticles, MSC-derived exosomes and artificial ectosomes, and MSC membrane-fused liposomes with natural or genetically engineered MSC membranes. MSC mimicking nanoencapsulations not only retain the targeting ability of MSCs but also have many advantages in terms of targeted drug delivery. Specifically, MSC mimicking nanoencapsulations are capable of encapsulating drugs with various components, including chemotherapeutic agents, nucleic acids, and proteins. Furthermore, there are fewer concerns over safety issues on MSC mimicking nanoencapsulations associated with mutagenesis even when using genetically engineered MSCs, because MSC mimicking nanoencapsulations use only the membrane fraction of MSCs. Genetic engineering is a promising route in clinical settings, where nano-encapsulated technology strategies are combined. In this review, the mechanism underlying MSC homing and the advantages of MSC mimicking nanoencapsulations are discussed. In addition, genetic engineering of MSCs and MSC mimicking nanoencapsulation is described as a promising strategy for the treatment of immune-related diseases.

Genetic modification of mesenchymal stem cells to enhance their anti-tumor efficacy

Non-hematopoietic mesenchymal stem cells (MSCs) are widely used in regenerative medicine and tissue engineering as they possess multilineage differentiation potential and self-renewal properties. MSCs can be easily isolated from several tissues and expanded following standard cell culture procedures. MSCs have the capability of mobilization to the tumor site; so, they can automatically relocate to the tumor sites through their chemokine receptors following intravenous transplantation. In this respect, they can be used for MSC-based gene therapy. In this therapeutic technique, beneficial genes are inserted by viral and non-viral methods into MSCs that lead to transgene expression in them. Genetic modifications of MSCs have been widely studied and thoroughly investigated to further enhance their therapeutic efficacy. The current strategies of MSC-based therapies emphasize the incorporation of beneficial genes, which will enhance the therapeutic ability of MSCs and have better homing efficiency. Non-viral methods produce less toxicity and immunogenicity compared to viral gene delivery methods and thus represent a promising and efficient tool for the genetic engineering of MSCs. Several non-viral gene delivery strategies have been developed in recent decades, and some of them have been used for MSCs modification. This mini review provides an overview of current gene delivery approaches used for the genetic modification of MSCs with beneficial genes including viral and non-viral vectors.

Therapeutic Applications of Genes and Gene-Engineered Mesenchymal Stem Cells for Femoral Head Necrosis.

Osteonecrosis of the femoral head (ONFH) is a common and disabling joint disease. Although there is no clear consensus on the complex pathogenic mechanism of ONFH, trauma, abuse of glucocorticoids, and alcoholism are implicated in its etiology. The therapeutic strategies are still limited, and the clinical outcomes are not satisfactory. Mesenchymal stem cells (MSCs) have been shown to exert a positive impact on ONFH in preclinical experiments and clinical trials. The beneficial properties of MSCs are due, at least in part, to their ability to home to the injured tissue, secretion of paracrine signaling molecules, and multipotentiality. Nevertheless, the regenerative capacity of transplanted cells is impaired by the hostile environment of necrotic tissue in vivo, limiting their clinical efficacy. Recently, genetic engineering has been introduced as an attractive strategy to improve the regenerative properties of MSCs in the treatment of early-stage ONFH. This review summarizes the function of several genes used in the engineering of MSCs for the treatment of ONFH. Further, current challenges and future perspectives of genetic manipulation of MSCs are discussed. The notion of genetically engineered MSCs functioning as a "factory" that can produce a significant amount of multipotent and patient-specific therapeutic product is emphasized.

Ferrimagnetic Nanochains‐Based Mesenchymal Stem Cell Engineering for Highly Efficient Post‐Stroke Recovery

AbstractUnsatisfactory post‐stroke recovery has long been a negative factor in the prognosis of ischemic stroke due to the lack of pharmacological treatments. Mesenchymal stem cells (MSCs)‐based therapy has recently emerged as a promising strategy redefining stroke treatment; however, its effectiveness has been largely restricted by insufficient therapeutic gene expression and inadequate cell numbers in the ischemic cerebrum. Herein, a non‐viral and magnetic field‐independent gene transfection approach is reported, using magnetosome‐like ferrimagnetic iron oxide nanochains (MFIONs), to genetically engineer MSCs for highly efficient post‐stroke recovery. The 1D MFIONs show efficient cellular uptake by MSCs, which results in highly efficient genetic engineering of MSCs to overexpress brain‐derived neurotrophic factor for treating ischemic cerebrum. Moreover, the internalized MFIONs promote the homing of MSCs to the ischemic cerebrum by upregulating CXCR4. Consequently, a pronounced recovery from ischemic stroke is achieved using MFION‐engineered MSCs in a mouse model.

Mesenchymal stem cells as the game-changing tools in the treatment of various organs disorders: Mirage or reality?

Recently a growing attention in scientific community has been gathered on potential application of mesenchymal stem cells (MSCs) in various fields of medicine. Owing to the fact that they can be easily isolated from different sources, and simply proliferated in large quantities while keeping their original biological characteristics, they can be successfully used as cell-based therapeutics. Engineering MSCs and other type of stem cells to be carriers of therapeutic agents is a new tactic in the targeted gene and cell therapy of cancers and degenerative diseases. Various useful properties of MSCs including tropism toward tumor/injury site(s), weakly immunogenic, production of anti-inflammatory molecules, and safety against normal tissues have made them prone for regenerative medicine, targeted therapy and treating injured tissues, and immunological abnormalities. In this review, we introduce latest advances, methods, and applications of MSCs in gene therapy of various malignant organ disorders. Additionally, we will cover the problems and challenges which researchers have faced with when trying to translate their basic experimental findings in MSCs research to clinically applicable therapeutics.

Abstract 3045: Engineering Mesenchymal Stem Cells (MSCs) to support tumor-targeted delivery of exosome-encapsulated microRNA-379

Abstract Mesenchymal Stem Cells (MSCs) are multipotent stromal cells known to migrate specifically to the sites of tumors and metastases, raising potential as tumor-targeted delivery vehicles for therapeutic agents. MSCs secrete exosomes containing genetic material including microRNAs (miRs), that are effectively taken up by cells. Previous work has shown miR-379 to be significantly reduced in breast tumor tissue, highlighting a potential tumor suppressor role. This study aimed to establish a mechanism of action for miR-379, and to engineer MSCs to secrete exosomes enriched with the miR for tumor-targeted delivery. Methods: RNA was isolated from breast tumors and matching lymph node metastases from the same patients, and miR-379 expression quantified by RQ-PCR. HCC1954 breast cancer cells were transduced with lentivirus to express elevated miR-379 (HCC-379) or a control sequence (HCC-NTC). Cells were implanted into the mammary fat pad (MFP) of mice and tumor progression monitored. Subsequently, MSCs were transduced to generate MSC-379 and MSC-NTC. MSC-secreted exosomes were isolated by differential centrifugation, microfiltration and ultracentrifugation. The morphology, size and number of isolated exosomes was characterized using Transmission Electron Microscopy, Western Blot and Nanoparticle Tracking Analysis respectively. Exosomal miRs were analysed by RQ-PCR. MFP tumors were established using HCC1954-luciferase cells, followed by IV injection of MSC-379 or MSC-NTC cells, or sequential doses of exosomes derived from either cell population. Results: miR-379 expression was significantly reduced in lymph node metastases compared to primary tumors from the same patients (p=0.009), supporting a tumor suppressor role. Analysis of HCC-379 and HCC-NTC tumor growth In Vivo showed no difference in tumor size, however an increase in tumour necrosis (5-50%) and decrease in lymph node invasion was observed in HCC-379 tumors. Investigation of a potential role for miR-379 in regulating COX-2, revealed an inverse relationship (r = -0.48, p=0.02) at a mRNA level, further confirmed at a protein level. MSC-379 cells showed no significant change in migratory or proliferative capacity In Vitro. MSC-secreted exosomes were confirmed to be the correct morphology and size (30-120nm), and to express the exosome-associated protein CD63. An increase in miR-379 (>5 fold) was observed in exosomes secreted by MSC-379 compared to MSC-NTC cells. Administration of MSC-379 or MSC-NTC cells, or exosomes derived from either cell population, was well tolerated In Vivo with no adverse effects observed. Monitoring tumor response to therapy using IVIS is ongoing. Conclusion: The data presented supports miR-379 as a potent tumor suppressor in breast cancer, mediated in part through regulation of COX-2. Engineering tumor-targeted MSCs to secrete exosomes enriched with miR-379 holds exciting potential as a novel therapy for breast cancer. Citation Format: Killian P. O'Brien, Katie Gilligan, Sonja Khan, Brian Moloney, Kerry Thompson, Pierce Lalor, Peter Dockery, Helen Ingoldsby, Michael J. Kerin, Roisin M. Dwyer. Engineering Mesenchymal Stem Cells (MSCs) to support tumor-targeted delivery of exosome-encapsulated microRNA-379 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3045. doi:10.1158/1538-7445.AM2017-3045

Abstract P6-04-01: Engineering mesenchymal stem cells(MSCs) to secrete tumour-suppressing exosomes for breast cancer therapy

Abstract Introduction: Mesenchymal Stem Cells(MSCs) are multipotent stromal cells that are known to engraft into tumours, raising their potential as tumour-targeted delivery vehicles. MSCs secrete tiny vesicles known as exosomes, which contain genetic material including microRNAs, and are effectively taken up by recipient cells. This study aimed to characterise a tumour-suppressing microRNA, miR-379, and engineer MSCs to secrete exosomes enriched with the microRNA. Methods: The mechanism of action of miR-379 In Vivo was determined through lentivirus-mediated upregulation of miR-379 in breast tumours, and analysis of changes in tumour angiogenesis, proliferation and progression. Subsequently, MSCs were engineered with lenti-379 and any impact on MSC migration, proliferation and morphology was assessed. MSC-secreted exosomes were isolated and characterised using Transmission Electron Microscopy(TEM) and Western Blot. The exosomal microRNA content was analysed by RQ-PCR, and transfer between cell populations visualised using confocal microscopy. Results: While elevated miR-379 expression did not impact tumour size In Vivo, an increase in tumour necrosis and decrease in invasion was observed. MSCs were successfully transduced with miR-379, resulting in a distinct change in cell morphology. Despite this, MSC-379 cells maintained inherent tumour-targeted migratory capacity, with no impact on proliferation observed. MSC-379 derived exosomes were 30-120nm in size and expressed the exosome-associated protein CD63. A 5-fold increase in miR-379 was observed in engineered exosomes. Successful transfer of RFP-labelled MSC-derived exosomes to breast cancer cells was visualised using confocal microscopy. Conclusion: Engineering tumour-targeted MSCs to secrete exosomes enriched with miR-379 holds exciting potential as a novel therapy for breast cancer. Citation Format: O'Brien KP, Khan S, Thompson K, Joyce D, Lalor P, Dockery P, Ingoldsby H, Kerin MJ, Dwyer RM. Engineering mesenchymal stem cells(MSCs) to secrete tumour-suppressing exosomes for breast cancer therapy [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P6-04-01.

Local Inhibition of Complement Improves Mesenchymal Stem Cell Viability and Function After Administration.

The results of recent clinical trials using mesenchymal stem cells (MSCs) have been unsatisfactory, indicating that current MSC-based therapies need to be improved. We and others have previously demonstrated that MSCs activate complement by unknown mechanisms after infusion, leading to damaged MSCs. In the study reported here, we found that incorporation of N-glycolylneuraminic acid onto MSCs during in vitro culture was a factor in the activation of complement by MSCs. In addition, we developed a way to "paint" heparin onto MSCs. This novel method improved the viability of MSCs and enhanced their function after infusion by directly inhibiting complement and by recruiting factor H, another potent complement inhibitor in serum, onto the surface of the MSCs. These data suggest that cell-surface engineering of MSCs with heparin to locally inhibit complement activation on MSCs might be a straightforward and effective method for improving the outcome of current MSC-based therapies.

Dual targeting and enhanced cytotoxicity to HER2-overexpressing tumors by immunoapoptotin-armored mesenchymal stem cells

Mesenchymal stem cells (MSCs) are promising vehicles for the delivery of anticancer agents in cancer therapy. However, the tumor targeting of loaded therapeutics is essential. Here, we explored a dual-targeting strategy to incorporate tumor-tropic MSC delivery with HER2-specific killing by the immunoapoptotin e23sFv-Fdt-tBid generated in our previous studies. The MSC engineering allowed simultaneous immunoapoptotin secretion and bioluminescence detection of the modified MSCs. Systemic administration of the immunoapoptotin-engineered MSCs was investigated in human HER2-reconstituted syngeneic mouse models of orthotopic and metastatic breast cancer, as well as in a xenograft nude mouse model of orthotopic gastric cancer. In vivo dual tumor targeting was confirmed by local accumulation of the bioluminescence-imaged MSCs and persistence of His-immunostained immunoapoptotins in tumor sites. The added tumor preference of MSC-secreted immunoapoptotins resulted in a significantly stronger antitumor effect compared with purified immunoapoptotins and Jurkat-delivered immunoapoptotins. This immunoapoptotin-armored MSC strategy provides a rationale for its use in extended malignancies by combining MSC mobility with redirected immunoapoptotins against a given tumor antigen.

Non-viral gene activated matrices for mesenchymal stem cells based tissue engineering of bone and cartilage.

Recent regenerative medicine and tissue engineering strategies for bone and cartilage repair have led to fascinating progress of translation from basic research to clinical applications. In this context, the use of gene therapy is increasingly being considered as an important therapeutic modality and regenerative technique. Indeed, in the last 20 years, nucleic acids (plasmid DNA, interferent RNA) have emerged as credible alternative or complement to proteins, which exhibited major issues including short half-life, loss of bioactivity in pathologic environment leading to high dose requirement and therefore high production costs. The relevance of gene therapy strategies in combination with a scaffold, following a so-called "Gene-Activated Matrix (GAM)" approach, is to achieve a direct, local and sustained delivery of nucleic acids from a scaffold to ensure efficient and durable cell transfection. Among interesting cells sources, Mesenchymal Stem Cells (MSC) are promising for a rational use in gene/cell therapy with more than 1700 clinical trials approved during the last decade. The aim of the present review article is to provide a comprehensive overview of recent and ongoing work in non-viral genetic engineering of MSC combined with scaffolds. More specifically, we will show how this inductive strategy can be applied to orient stem cells fate for bone and cartilage repair.

Minicircle microporation-based non-viral gene delivery improved the targeting of mesenchymal stem cells to an injury site.

Genetic engineering approaches to improve the therapeutic potential of mesenchymal stem cells (MSCs) have been made by viral and non-viral gene delivery methods. Viral methods have severe limitations in clinical application because of potential oncogenic, pathogenic, and immunogenic risks, while non-viral methods have suffered from low transfection efficiency and transient weak expression as MSCs are hard-to-transfect cells. In this study, minicircle, which is a minimal expression vector free of bacterial sequences, was employed for MSC transfection as a non-viral gene delivery method. The conventional cationic liposome method was not effective for MSC transfection as it resulted in very low transfection efficiency (less than 5%). Microporation, a new electroporation method, greatly improved the transfection efficiency of minicircles by up to 66% in MSCs without any significant loss of cell viability. Furthermore, minicircle microporation generated much stronger and prolonged transgene expression compared with plasmid microporation. When MSCs microporated with minicircle harboring firefly luciferase gene were subcutaneously injected to mice, the bioluminescence continued for more than a week, whereas the bioluminescence of the MSCs induced by plasmid microporation rapidly decreased and disappeared in mice within three days. By minicircle microporation as a non-viral gene delivery, MSCs engineered to overexpress CXCR4 showed greatly increased homing ability toward an injury site as confirmed through invivo bioluminescence imaging in mice. In summary, the engineering of MSCs through minicircle microporation is expected to enhance the therapeutic potential of MSCs in clinical applications.

Engineered Cell Therapy: A Successful Approach to Treat Cancer

Cancer is the abnormality which happens in the cell cycle, resulting in uncontrolled cell division and is the second largest cause of deaths in the world accounting 13% of all deaths followed by the cardiovascular diseases. Finding a therapeutic solution for cancer is a continuous process. A number of therapeutic approaches like chemotherapy, preventive therapies, radiation and magnetic therapy, adjuvant therapy, Immunotherapy, gene therapy, cell transplantation therapy, Hyperthermia and surgery are under research in order to treat cancer. Targeted therapy is the most preferred way to treat cancer globally and researchers are focusing on the different ways of targeted therapy. Gene therapy with its first approved drug for cancer (Gendicine™) in China revolutionized the cancer drugs but a number of questions in scientific community around the world and its rejection in European and American market raised question marks on its authenticity as cancer drug. Successful clinical trials for mesenchymal stem cell (MSCs) and engineered cells based therapy against cancer emerged the concept of gene and cell therapy for cancer and a number of clinical trials also produced successful results in this case. Engineered cells are new agents of targeted cancer therapy and have been considered by researchers, as a promising therapeutic candidates. Engineered cell therapy (combination of gene and cell therapy) as a part of targeted therapy of cancer may provide a valuable resource. T-Cell engineering has faced successful results, whereas MSC engineering is passing through a transition phase. Successful engineering of MSCs could be a hope for cancer patients in near future.

MSCs: Is this the future therapeutic for cancer?

Cancer is nowadays one of the main causes of death worldwide. The numbers have shown that one in three people will develop cancer at some point in their lives. Cancer is a major issue for the whole humanity, and therefore a lot of research has been running for the past years in order to understand the mechanisms that underlie tumorigenesis and eventually cancer formation, with the perspective to discover new approaches for effective treatment. Gene therapy strategies that intended to tackle cancer systemically are often impaired by inefficient delivery of the vector to the tumor site. Several studies have shown the possibility of using mesenchymal stem cells (MSCs) as a future therapeutic mechanism against cancer, since they possess important features such as the ability to home to and target cancer cells. The engineering of MSCs to produce and deliver an apoptotic factor, calledtumor necrosis factor-related apoptosis-inducing ligand (TRAIL) has been studied excessively. TRAIL is a transmembrane protein that causes selective apoptosis of tumor cells but does not have any harmful effects on the normal neighboring cells. Experiments have shown that this approach has significant results in mouse models and has now proceeded for clinical trials.