Nucleofection optimization and in vitro anti-tumourigenic effect of TRAIL-expressing human adipose-derived mesenchymal stromal cells

Enhanced anticancer efficacy of primed natural killer cells via coacervate-mediated exogenous interleukin-15 delivery

Effective exogenous delivery of interleukin (IL)-15 to natural killer (NK) cells with subsequent anticancer efficacy could be a promising immune cell-based cancer immunotherapy. For the protection of encapsulated cargo IL-15 while maintaining its bioactivity under physiological conditions, we utilized a coacervate (Coa) consisting of a cationic methoxy polyethylene glycol-poly(ethylene arginyl aspartate diglyceride) (mPEG-PEAD) polymer, anionic counterpart heparin, and cargo IL-15. mPEGylation into the backbone cation effectively preserved the colloidal stability of Coa in harsh environments and enhanced the protection of cargo IL-15 than normal Coa without mPEGylation. Proliferation and anticancer efficacy of primed NK cells through co-culture with multiple cancer cell lines were enhanced in the mPEG-Coa group due to the maintained bioactivity of cargo IL-15 during the ex vivo expansion of NK cells. These facilitated functions of NK cells were also supported by the increased expression of mRNAs related to anticancer effects of NK cells, including cytotoxic granules, death ligands, anti-apoptotic proteins, and activation receptors. In summary, our Coa-mediated exogenous IL-15 delivery could be an effective ex vivo priming technique for NK cells with sustained immune activation that can effectively facilitate its usage for cancer immunotherapy.

Interplay between mesenchymal stem cell and tumor and potential application

Mesenchymal stem cells (MSCs) possess the capabilities of self-renewal and multipotent differentiation. Firstly isolated from bone marrow, MSCs are subsequently identified from various post-natal tissue types. Based the differentiation into tissue-specific cells, MSCs were capable of replacing damaged and diseased tissues. In addition, MSCs have been demonstrated to possess important immunomodulatory properties. Increasing data showed that MSCs exhibited tropism for sites of the tumor microenvironment and interacted with tumor cells closely through paracrine signaling. Therefore, better understanding of crosstalk between MSCs and tumor cells will be able to develop potential strategies in the treatment of tumors in the future. Herein, we summarize the research progress of the influence of MSCs on tumor cells and the prospect of their application in tumor therapy in this review.

Efficacy of mesenchymal stem cells in the treatment of gastrointestinal malignancies

Mesenchymal stem cells (MSCs), which are a kind of stem cell, possess an immune privileged nature, tumour homing features, and multi-lineage differentiation ability. MSCs have been studied in many fields, such as tissue engineering, nervous system diseases, and cancer treatment. In recent years, an increasing number of researchers have focused on the effects of MSCs on various kinds of tumours. However, the concrete anticancer efficacy of MSCs is still controversial. Gastrointestinal (GI) malignancies are the major causes of cancer-related death worldwide. The interactions of MSCs and GI cancer cells in specific conditions have attracted increasing attention. In this review, we introduce the characteristics of MSCs and analyse the effects of MSCs on GI malignancies, including gastric cancer, hepatoma, pancreatic cancer, and colorectal cancer. In addition, we also provide our perspectives on why MSCs may play different roles in GI malignancies and further research directions to increase the treatment efficacy of MSCs on GI malignancies.

Therapeutic Potential of Mesenchymal Stem Cells for Cancer Therapy

Mesenchymal stem cells (MSCs) are among the most frequently used cell type for regenerative medicine. A large number of studies have shown the beneficial effects of MSC-based therapies to treat different pathologies, including neurological disorders, cardiac ischemia, diabetes, and bone and cartilage diseases. However, the therapeutic potential of MSCs in cancer is still controversial. While some studies indicate that MSCs may contribute to cancer pathogenesis, emerging data reported the suppressive effects of MSCs on cancer cells. Because of this reality, a sustained effort to understand when MSCs promote or suppress tumor development is needed before planning a MSC-based therapy for cancer. Herein, we provide an overview on the therapeutic application of MSCs for regenerative medicine and the processes that orchestrates tissue repair, with a special emphasis placed on cancer, including central nervous system tumors. Furthermore, we will discuss the current evidence regarding the double-edged sword of MSCs in oncological treatment and the latest advances in MSC-based anti-cancer agent delivery systems.

Mesenchymal Stem Cell Expressing TRAIL as Targeted Therapy against Sensitised Tumour

Tapping into the ability of engineered mesenchymal stem cells (MSCs) to mobilise into the tumour has expanded the scope of cancer treatment. Engineered MSCs expressing tumour necrosis factor (TNF)-related apoptosis inducing ligand (MSC-TRAIL) could serve as a platform for an efficient and targeted form of therapy. However, the presence of cancer stem cells (CSCs) that are resistant to TRAIL and apoptosis may represent a challenge for effective treatment. Nonetheless, with the discovery of small molecular inhibitors that could target CSCs and tumour signalling pathways, a higher efficacy of MSC-TRAIL mediated tumour inhibition can be achieved. This might pave the way for a more effective form of combined therapy, which leads to a better treatment outcome. In this review, we first discuss the tumour-homing capacity of MSCs, its effect in tumour tropism, the different approach behind genetically-engineered MSCs, and the efficacy and safety of each agent delivered by these MSCs. Then, we focus on how sensitisation of CSCs and tumours using small molecular inhibitors can increase the effect of these cells to either TRAIL or MSC-TRAIL mediated inhibition. In the conclusion, we address a few questions and safety concerns regarding the utilization of engineered MSCs for future treatment in patients.

Comparison and immunobiological characterization of retinoic acid inducible gene-I-like receptor expression in mesenchymal stromal cells

Due to their immunomodulatory and regenerative properties, Mesenchymal stromal cells (MSC) have generated major interests in several clinical settings including transplantation and inflammatory diseases. MSC functions can be influenced by their tissue origin. Their microenvironment strongly affects their biology notably through TLR sensing. In this study, we show that MSC isolated from four different sources express another type of cytosolic pathogen recognition receptors known as retinoic acid inducible gene-I (RIG-I)-like receptors (RLR). RLR activation in MSC induces the production of Type I IFN (IFN-β) and Type III IFN (IFN-λ1). The highest producers are adipose tissue(AT)-MSC. We further show that Interferon production is induced through TBK1/IKK-ε signaling and IRF7 phosphorylation. Depending on MSC source, the knockdown of TLR3 and/or RIG-I decreases the MSC response to RLR ligand poly(I:C)/Lyovec. Among the different MSC types, AT-MSCs display the highest sensitivity to viral stimuli as shown by the alteration of their viability after prolonged stimulation. Our work indicates that this could be linked to an increase of pro-apoptotic Noxa expression. Finally, the expression of IDO1 and LIF upon RLR activation indicate the increase of MSC immunomodulatory potential, especially in AT-MSCs. Altogether, these data should be considered when designing MSC-based therapy in clinical settings where inflammation or infection are present.

Immunomodulatory effects of OX40Ig gene-modified adipose tissue-derived mesenchymal stem cells on rat kidney transplantation

Recent studies have suggested that adipose tissue-derived mesenchymal stem cell (ADSC) therapy and OX40 costimulation blockade are two immunomodulatory strategies used to suppress the immune response to alloantigens. However, relatively little has been reported regarding the immunomodulatory potential of the abilityof these two strategies to synergize. Thus, in the present study, we aimed to investigate OX40-Ig fusion protein (OX40Ig) expression in ADSCs and to validate their more potent immunosuppressive activity in preventing renal allograft rejection. For this purpose, ADSCs from Lewis rats were transfected with the recombinant plasmid, pcDNA3.1(-)OX40Ig, by nucleofection. The ADSCs transduced with the plasmid (termed ADSCsOX40Ig) or untransduced ADSCs (termed ADSCsnative) were added to allostimulated mixed lymphocyte reaction (MLR) in vitro. In vivo, ADSCsOX40Ig, ADSCsnative, or PBS were administered to an allogeneic renal transplantation model, and the therapeutic effects, as well as the underlying mechanisms were examined. The results revealed that both the ADSCsnative and ADSCsOX40Ig significantly suppressed T cell proliferation and increased the percentage of CD4+CD25+ regulatory T cells in allogeneic MLR assays, with the ADSCsOX40Ig being more effective. Furthermore, the results from our in vivo experiments revealed that compared with the ADSCsnative or PBS group, the administration of autologous ADSCsOX40Ig markedly prolonged the mean survival time of renal grafts, reduced allograft rejection, and significantly downregulated the mRNA expression of intragraft interferon-γ (IFN-γ) , and upregulated the mRNA expression of interleukin (IL)‑10, transforming growth factor-β (TGF-β) and forkhead box protein 3 (Foxp3). The findings of our study indicate that the use of ADSCsOX40Ig is a promising strategy for preventing renal allograft rejection. This strategy provides the synergistic benefits of ADSC immune modulation and OX40-OX40L pathway blockade, and may therefore have therapeutic potential in clinical renal transplantation.

Mesenchymal Stem Cells Engineered to Secrete Pigment Epithelium-Derived Factor Inhibit Tumor Metastasis and the Formation of Malignant Ascites in a Murine Colorectal Peritoneal Carcinomatosis Model

The therapeutic effects of conventional treatments for advanced colorectal cancer with colorectal peritoneal carcinomatosis (CRPC) and malignant ascites are not very encouraging. Vascular endothelial growth factor-A/vascular permeability factors (VEGF-A/VPF) play key roles in the formation of malignant ascites. In previous work, we demonstrated that pigment epithelium-derived factor (PEDF) antagonized VEGF-A and could repress tumor growth and suppress metastasis in several cancer types. Thus, PEDF may be a therapeutic candidate for treating malignant ascites. Mesenchymal stem cells (MSCs) are promising tools for delivering therapeutic agents in cancer treatment. In the study, MSCs derived from bone marrow were efficiently engineered to secrete human PEDF by adenoviral transduction. Then, intraperitoneal Ad-PEDF-transduced MSCs were analyzed with respect to CRPC and malignant ascites in a CT26 CRPC model. MSCs engineered to secrete PEDF through adenoviral transduction significantly inhibited tumor metastasis and malignant ascites formation in CT26 CRPC mice. Antitumor mechanisms of MSCs-PEDF (MSCs transduced with Ad-PEDF: MOI 500) were associated with inhibiting tumor angiogenesis, inducing apoptosis, and restoring the VEGF-A/sFLT-1 ratio in ascites. Moreover, MSC-mediated Ad-PEDF delivery reduced production of adenovirus-neutralizing antibodies, prolonged PEDF expression, and induced MSCs-PEDF migration toward tumor cells. As a conclusion, MSCs engineered to secrete PEDF by adenoviral transduction may be a therapeutic approach for suppressing tumor metastasis and inhibiting malignant ascites production in CRPC.