Preclinical Evaluation of a Single Intravenous Infusion of hUC-MSC (BX-U001) in Rheumatoid Arthritis.

Rheumatoid arthritis (RA) is an inflammatory disease of the joints, which causes severe pain and excessive systemic circulation of harmful inflammatory cytokines. Current treatments are limited, with some patients not responding well, and some experiencing severe and detrimental side effects. Mesenchymal stem cells (MSC) are cell-based therapeutics being evaluated as potent immunomodulators in RA and may provide relief to patients not responding well to drug-based treatments. We evaluated the safety and efficacy of BX-U001 human umbilical cord tissue-derived mesenchymal stem cells (hUC-MSC) to treat RA, in support of a successful investigational new drug application. A collagen-induced arthritis (CIA) mouse model of RA was established in DBA/1 J mice. Mice from the treatment assessment group were given a tail vein infusion of hUC-MSC 24 days after primary RA induction, while control assessment (CA) group mice were given cell-free carrier solution. All animals were evaluated daily for RA symptoms via clinical scoring, blood was taken periodically for cytokine analysis, and mice were dissected at end point for histological analysis. A linear mixed model was used to compare the rate of change among groups. The clinical scores of TA group were significantly reduced compared with CA group (P < 0.01), indicating therapeutic effects. The histological scores of the joints in TA group were significantly lower than those in the CA group (P < 0.05), but had no significant difference compared with Healthy groups (P > 0.05). The concentration of (interleukin) IL-6 in TA group was significantly reduced by 80.0% (P < 0.0001) 2 days after treatment and by 93.4% at the experimental endpoint compared with levels prior to hUC-MSC injection. A single intravenous infusion of hUC-MSC (2 × 106 cells/mouse), to CIA-induced DBA/1 J mice, resulted in significant alleviation of RA symptoms and may provide significant therapeutic benefits in humans.

Genetically Engineered Cell-Derived Nanoparticles for Targeted Breast Cancer Immunotherapy.

Exosomes are nanosized membranous vesicles secreted by a variety of cells. Due to their unique and pharmacologically important properties, cell-derived exosome nanoparticles have drawn significant interest for drug development. By genetically modifying exosomes with two distinct types of surface-displayed monoclonal antibodies, we have developed an exosome platform termed synthetic multivalent antibodies retargeted exosome (SMART-Exo) for controlling cellular immunity. Here, we apply this approach to human epidermal growth factor receptor 2 (HER2)-expressing breast cancer by engineering exosomes through genetic display of both anti-human CD3 and anti-human HER2 antibodies, resulting in SMART-Exos dually targeting T cell CD3 and breast cancer-associated HER2 receptors. By redirecting and activating cytotoxic T cells toward attacking HER2-expressing breast cancer cells, the designed SMART-Exos exhibited highly potent and specific anti-tumor activity both in vitro and in vivo. This work demonstrates preclinical feasibility of utilizing endogenous exosomes for targeted breast cancer immunotherapy and the SMART-Exos as a broadly applicable platform technology for the development of next-generation immuno-nanomedicines.

Meta-analysis of preclinical studies of mesenchymal stromal cells to treat rheumatoid arthritis.

BACKGROUND: This study aims to evaluate the quality of preclinical data, determine the effect sizes, and identify experimental measures that inform efficacy using mesenchymal stromal (or stem) cells (MSC) therapy in animal models of rheumatoid arthritis (RA). METHODS: Literature searches were performed on MSC preclinical studies to treat RA. MSC treatment effect sizes were determined by the most commonly used outcome measures, including paw thickness, clinical score, and histological score. FINDINGS: A total of 48 studies and 94 treatment arms were included, among which 42 studies and 79 treatment arms reported that MSC improved outcomes. The effect sizes of RA treatments using MSC, when compared to the controls, were: paw thickness was ameliorated by 53.6% (95% confidence interval (CI): 26.7% -80.4%), histological score was decreased by 44.9% (95% CI: 33.3% -56.6%), and clinical score was decreased by 29.9% (95% CI: 16.7% -43.0%). Specifically, our results indicated that human umbilical cord derived MSC led to large improvements of the clinical score (-42.1%) and histological score (-51.4%). INTERPRETATION: To the best of our knowledge, this meta-analysis is to quantitatively answer whether MSC represent a robust RA treatment in animal models. It suggests that in preclinical studies, MSC have consistently exhibited therapeutic benefits. The findings demonstrate a need for considering variations in different animal models and treatment protocols in future studies using MSC to treat RA in humans to maximise the therapeutic gains in the era of precision medicine. FUNDS: NIH [1DP2CA195763], Baylx Inc.: BI-206512, NINDS/NIH Training Grant [Award# NS082174].

Reprogramming Exosomes as Nanoscale Controllers of Cellular Immunity.

Exosomes are naturally occurring membranous vesicles secreted by various types of cells. Given their unique and important biological and pharmacological properties, exosomes have been emerging as a promising form of nanomedicine acting via efficient delivery of endogenous and exogenous therapeutics. Here we explore a new concept of utilizing endogenously derived exosomes as artificial controllers of cellular immunity to redirect and activate cytotoxic T cells toward cancer cells for killing. This was achieved through genetically displaying two distinct types of antibodies on exosomal surface. The resulting synthetic multivalent antibodies retargeted exosomes (SMART-Exos), which express monoclonal antibodies specific for T-cell CD3 and cancer cell-associated epidermal growth factor receptor (EGFR), were shown to not only induce cross-linking of T cells and EGFR-expressing breast cancer cells but also elicit potent antitumor immunity both in vitro and in vivo. This proof-of-concept study demonstrates a novel application of exosomes in cancer immunotherapy and may provide a general and versatile approach for the development of a new class of cell-free therapy.

Toward the design of a catalytic metallodrug: selective cleavage of G-quadruplex telomeric DNA by an anticancer copper-acridine-ATCUN complex.

Telomeric DNA represents a novel target for the development of anticancer drugs. By application of a catalytic metallodrug strategy, a copper-acridine-ATCUN complex (CuGGHK-Acr) has been designed that targets G-quadruplex telomeric DNA. Both fluorescence solution assays and gel sequencing demonstrate the CuGGHK-Acr catalyst to selectively bind and cleave the G-quadruplex telomere sequence. The cleavage pathway has been mapped by matrix assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) experiments. CuGGHK-Acr promotes significant inhibition of cancer cell proliferation and shortening of telomere length. Both senescence and apoptosis are induced in the breast cancer cell line MCF7.