Endogenous stem cell mobilization and localized immunosuppression synergistically ameliorate DSS-induced Colitis in mice.

BACKGROUND: Stem cell therapy is a promising alternative for inflammatory diseases and tissue injury treatment. Exogenous delivery of mesenchymal stem cells is associated with instant blood-mediated inflammatory reactions, mechanical stress during administration, and replicative senescence or change in phenotype during long-term culture in vitro. In this study, we aimed to mobilize endogenous hematopoietic stem cells (HSCs) using AMD-3100 and provide local immune suppression using FK506, an immunosuppressive drug, for the treatment of inflammatory bowel diseases. METHODS: Reactive oxygen species (ROS)-responsive FK506-loaded thioketal microspheres were prepared by emulsification solvent-evaporation method. Thioketal vehicle based FK506 microspheres and AMD3100 were co-administered into male C57BL6/J mice with dextran sulfate sodium (DSS) induced colitis. The effect of FK506-loaded thioketal microspheres in colitis mice were evaluated using disease severity index, myeloperoxidase activity, histology, flow cytometry, and gene expression by qRT-PCR. RESULTS: The delivery of AMD-3100 enhanced mobilization of HSCs from the bone marrow into the inflamed colon of mice. Furthermore, targeted oral delivery of FK506 in an inflamed colon inhibited the immune activation in the colon. In the DSS-induced colitis mouse model, the combination of AMD-3100 and FK506-loaded thioketal microspheres ameliorated the disease, decreased immune cell infiltration and activation, and improved body weight, colon length, and epithelial healing process. CONCLUSION: This study shows that the significant increase in the percentage of mobilized hematopoietic stem cells in the combination therapy of AMD and oral FK506 microspheres may contribute to a synergistic therapeutic effect. Thus, low-dose local delivery of FK506 combined with AMD3100 could be a promising alternative treatment for inflammatory bowel diseases.

Non-canonical deubiquitination of OTUB1 induces IFNγ-mediated cell cycle arrest via regulation of p27 stability.

The deubiquitinase OTUB1, implicated as a potential oncogene in various tumors, lacks clarity in its regulatory mechanism in tumor progression. Our study investigated the effects and underlying mechanisms of OTUB1 on the breast cancer cell cycle and proliferation in IFNγ stimulation. Loss of OTUB1 abrogated IFNγ-induced cell cycle arrest by regulating p27 protein expression, whereas OTUB1 overexpression significantly enhanced p27 expression even without IFNγ treatment. Tyr26 phosphorylation residue of OTUB1 directly bound to p27, modulating its post-translational expression. Furthermore, we identified crucial lysine residues (K134, K153, and K163) for p27 ubiquitination. Src downregulation reduced OTUB1 and p27 expression, suggesting that IFNγ-induced cell cycle arrest is mediated by the Src-OTUB1-p27 signaling pathway. Our findings highlight the pivotal role of OTUB1 in IFNγ-induced p27 expression and cell cycle arrest, offering therapeutic implications.

Fabrication of stem cell heterospheroids with sustained-release chitosan and poly(lactic-co-glycolic acid) microspheres to guide cell fate toward chondrogenic differentiation.

Mesenchymal stem cell (MSC)-based therapies show great potential in treating various diseases. However, control of the fate of injected cells needs to be improved. In this work, we developed an efficient methodology for modulating chondrogenic differentiation of MSCs. We fabricated heterospheroids with two sustained-release depots, a quaternized chitosan microsphere (QCS-MP) and a poly (lactic-co-glycolic acid) microsphere (PLGA-MP). The results show that heterospheroids composed of 1 × 104 to 5 × 104 MSCs formed rapidly during incubation in methylcellulose medium and maintained high cell viability in long-term culture. The MPs were uniformly distributed in the heterospheroids, as shown by confocal laser scanning microscopy. Incorporation of transforming growth factor beta 3 into QCS-MPs and of dexamethasone into PLGA-MPs significantly promoted the expression of chondrogenic genes and high accumulation of glycosaminoglycan in heterospheroids. Changes in crucial metabolites in the dual drug depot-engineered heterospheroids were also evaluated using 1H NMR-based metabolomics analysis to verify their successful chondrogenic differentiation. Our heterospheroid fabrication platform could be used in tissue engineering to study the effects of various therapeutic agents on stem cell fate.

Cathepsin D promotes polarization of tumor-associated macrophages and metastasis through TGFBI-CCL20 signaling.

M2-like tumor-associated macrophages (TAMs) are risk factors for cancer progression and metastasis. However, the mechanisms underlying their polarization are still not fully understood. Although cathepsin D (Cat D) has been reported as a procarcinogenic factor, little is known about the functional role of Cat D in the tumor microenvironment (TME). This study aimed to explore the effect and molecular mechanisms of Cat D in the TME. Cat D knockout (KO) altered the cytokine secretion pattern and induced TAM reprogramming from the M2 to M1 subtype, thereby preventing epithelial-mesenchymal transition and tumor metastasis. Mechanistically, we identified transforming growth factor beta-induced protein (TGFBI) as a Cat D target protein that is specifically associated with TAM polarization. Elevated TGFBI expression in Cat D KO cancer cells resulted in a decline in M2-like TAM polarization. Our RNA-sequencing results indicated that the cancer cell-secreted chemokine CCL20 is a major secretory chemokine for Cat D-TGFBI-mediated TAM polarization. In contrast, Cat D overexpression accelerated TAM polarization into M2-like cells by suppressing TGFBI expression. In addition, the double Cat D and TGFBI KO rescued the inhibitory effects of Cat D KO on tumor metastasis by controlling TAM and T-cell activation. These findings indicated that Cat D contributes to cancer metastasis through TGFBI-mediated TAM reprogramming. Cat D deletion inhibits M2-like TAM polarization through TGFBI-mediated CCL20 expression, reprogramming the immunosuppressive TME. Our results open a potential new avenue for therapy focused on eliminating tumor metastasis.

Nanoparticle-based immunoengineering strategies for enhancing cancer immunotherapy.

Cancer immunotherapy is a groundbreaking strategy that has revolutionized the field of oncology compared to other therapeutic strategies, such as surgery, chemotherapy, or radiotherapy. However, cancer complexity, tumor heterogeneity, and immune escape have become the main hurdles to the clinical application of immunotherapy. Moreover, conventional immunotherapies cause many harmful side effects owing to hyperreactivity in patients, long treatment durations and expensive cost. Nanotechnology is considered a transformative approach that enhances the potency of immunotherapy by capitalizing on the superior physicochemical properties of nanocarriers, creating highly targeted tissue delivery systems. These advantageous features include a substantial specific surface area, which enhances the interaction with the immune system. In addition, the capability to finely modify surface chemistry enables the achievement of controlled and sustained release properties. These advances have significantly increased the potential of immunotherapy, making it more powerful than ever before. In this review, we introduce recent nanocarriers for application in cancer immunotherapy based on strategies that target different main immune cells, including T cells, dendritic cells, natural killer cells, and tumor-associated macrophages. We also provide an overview of the role and significance of nanotechnology in cancer immunotherapy.

Magnetic resonance imaging of pancreatic islets using tissue-adhesive particles containing iron oxide nanoparticles.

Post-transplantation tracking of pancreatic islets is a prerequisite for advancing cell therapy to treat type 1 diabetes. Magnetic resonance imaging (MRI) has emerged as a safe and non-invasive technique for visualizing cells in clinical applications. In this study, we proposed a novel MRI contrast agent formulation by encapsulating iron oxide nanoparticles (IONPs) in poly(lactic-co-glycolic acid) (PLGA) particles functionalized with a tissue adhesive polydopamine (PD) layer (IONP-PLGA-PD MS). Intriguingly, our particles facilitated efficient and robust labeling through a one-step process, allowing for the incorporation of a substantial amount of IONPs without detrimental impacts on the viability and functionality of pancreatic islets. The MRI signals emanating from islets labeled using our particles were found to be stable over 30 days in vitro and 60 days when transplanted under kidney capsules of diabetic mice. These results suggest that our approach provides a potential platform for monitoring the fate of pancreatic islets after transplantation.

Engineered therapeutic proteins for sustained-release drug delivery systems.

Proteins play a vital role in diverse biological processes in the human body, and protein therapeutics have been applied to treat different diseases such as cancers, genetic disorders, autoimmunity, and inflammation. Protein therapeutics have demonstrated their advantages, such as specific pharmaceutical effects, low toxicity, and strong solubility. However, several disadvantages arise in clinical applications, including short half-life, immunogenicity, and low permeation, leading to reduced drug effectiveness. The structure of protein therapeutics can be modified to increase molecular size, leading to prolonged stability and increased plasma half-life. Notably, the controlled-release delivery systems for the sustained release of protein drugs and preserving the stability of cargo proteins are envisioned as a potential approach to overcome these challenges. In this review, we summarize recent research progress related to structural modifications (PEGylation, glycosylation, poly amino acid modification, and molecular biology-based strategies) and promising long-term delivery systems, such as polymer-based systems (injectable gel/implants, microparticles, nanoparticles, micro/nanogels, functional polymers), lipid-based systems (liposomes, solid lipid nanoparticles, nanostructured lipid carriers), and inorganic nanoparticles exploited for protein therapeutics. STATEMENT OF SIGNIFICANCE: In this review, we highlight recent advances concerning modifying proteins directly to enhance their stability and functionality and discuss state-of-the-art methods for the delivery and controlled long-term release of active protein therapeutics to their target site. In terms of drug modifications, four widely used strategies, including PEGylation, poly amino acid modification, glycosylation, and genetic, are discussed. As for drug delivery systems, we emphasize recent progress relating to polymer-based systems, lipid-based systems developed, and inorganic nanoparticles for protein sustained-release delivery. This review points out the areas requiring focused research attention before the full potential of protein therapeutics for human health and disease can be realized.

Reactive oxygen species-responsive dual-targeted nanosystem promoted immunogenic cell death against breast cancer.

The development of an optimal treatment modality to improve the therapeutic outcome of breast cancer patients is still difficult. Poor antigen presentation to T cells is a major challenge in cancer immunotherapy. In this study, a synergistic immunotherapy strategy for breast cancer incorporating immune cell infiltration, immunogenic cell death (ICD), and dendritic cell (DC) maturation through a reactive oxygen species (ROS)-responsive dual-targeted smart nanosystem (anti-PD-L1-TKNP) for the simultaneous release of DOX, R848, and MIP-3α in the tumor microenvironment is reported. Following local injection, anti-PD-L1-DOX-R848-MIP-3α/thioketal nanoparticle (TKNP) converts tumor cells to a vaccine owing to the combinatorial effect of DOX-induced ICD, R848-mediated immunostimulatory properties, and MIP-3α-induced immune cell recruitment in the tumor microenvironment. Intratumoral injection of anti-PD-L1-DOX-R848-MIP-3α/TKNP caused significant regression of breast cancer. Mechanistic studies reveal that anti-PD-L1-DOX-R848-MIP-3α/TKNP specifically targets tumor tissue, resulting in maximum exposure of calreticulin (CRT) and HMGB1 in tumors, and significantly enhances intratumoral infiltration of CD4+ and CD8+ T cells in tumors. Therefore, a combined strategy using dual-targeted ROS-responsive TKNP highlights the significant application of nanoparticles in modulating the tumor microenvironment and could be a clinical treatment strategy for effective breast cancer management.

Tubeimoside-1 Enhances TRAIL-Induced Apoptotic Cell Death through STAMBPL1-Mediated c-FLIP Downregulation.

Tubeimoside-1 (TBMS-1), a traditional Chinese medicinal herb, is commonly used as an anti-cancer agent. In this study, we aimed to investigate its effect on the sensitization of cancer cells to tumor necrosis factor-related apoptosis-inducing ligand (TRAIL). Our results revealed that even though monotherapy using TBMS-1 or TRAIL at sublethal concentrations did not affect cancer cell death, combination therapy using TBMS-1 and TRAIL increased apoptotic cell death. Mechanistically, TBMS-1 destabilized c-FLIP expression by downregulating STAMBPL1, a deubiquitinase (DUB). Specifically, when STAMBPL1 and c-FLIP bound together, STAMBPL1 deubiquitylated c-FLIP. Moreover, STAMBPL1 knockdown markedly increased sensitivity to TRAIL by destabilizing c-FLIP. These findings were further confirmed in vivo using a xenograft model based on the observation that combined treatment with TBMS-1 and TRAIL decreased tumor volume and downregulated STAMBPL1 and c-FLIP expression levels. Overall, our study revealed that STAMBPL1 is essential for c-FLIP stabilization, and that STAMBPL1 depletion enhances TRAIL-mediated apoptosis via c-FLIP downregulation.

Dual receptor specific nanoparticles targeting EGFR and PD-L1 for enhanced delivery of docetaxel in cancer therapy.

Dual-receptor targeted (DRT) nanoparticles which contain two distinct targeting agents may exhibit higher cell selectivity, cellular uptake, and cytotoxicity toward cancer cells than single-ligand targeted nanoparticle systems without additional functionality. The purpose of this study is to prepare DRT poly(lactic-co-glycolic acid) (PLGA) nanoparticles for targeting the delivery of docetaxel (DTX) to the EGFR and PD-L1 receptor positive cancer cells such as human glioblastoma multiform (U87-MG) and human non-small cell lung cancer (A549) cell lines. Anti-EGFR and anti-PD-L1 antibody were decorated on DTX loaded PLGA nanoparticles to prepare DRT-DTX-PLGA via. single emulsion solvent evaporation method. Physicochemical characterizations of DRT-DTX-PLGA, such as particle size, zeta-potential, morphology, and in vitro DTX release were also evaluated. The average particle size of DRT-DTX-PLGA was 124.2 ± 1.1 nm with spherical and smooth morphology. In the cellular uptake study, the DRT-DTX-PLGA endocytosed by the U87-MG and A549 cells was single ligand targeting nanoparticle. From the in vitro cell cytotoxicity, and apoptosis studies, we reported that DRT-DTX-PLGA exhibited high cytotoxicity and enhanced the apoptotic cell compared to the single ligand-targeted nanoparticle. The dual receptor mediated endocytosis of DRT-DTX-PLGA showed a high binding affinity effect that leads to high intracellular DTX concentration and exhibited high cytotoxic properties. Thus, DRT nanoparticles have the potential to improve cancer therapy by providing selectivity over single-ligand-targeted nanoparticles.

Scalable and Uniform Fabrication of Dexamethasone-Eluting Depot-Engineered Stem Cell Spheroids as a Microtissue Construct to Target Bone Regeneration.

Potentiation of stem cell potency is critical for successful tissue engineering, especially for bone regeneration. Three-dimensional cell culture and bioactive molecule co-delivery with cells have been proposed to achieve this effect. Here, we provide a uniform and scalable fabrication of osteogenic microtissue constructs of mesenchymal stem cell (MSC) spheroids surface-engineered with dexamethasone-releasing polydopamine-coated microparticles (PD-DEXA/MPs) to target bone regeneration. The microparticle conjugation process was rapid and cell-friendly and did not affect the cell viability or key functionalities. The incorporation of DEXA in the conjugated system significantly enhanced the osteogenic differentiation of MSC spheroids, as evidenced by upregulating osteogenic gene expression and intense alkaline phosphatase and alizarin red S staining. In addition, the migration of MSCs from spheroids was tested on a biocompatible macroporous fibrin scaffold (MFS). The result showed that PD-DEXA/MPs were stably anchored on MSCs during cell migration over time. Finally, the implantation of PD-DEXA/MP-conjugated spheroid-loaded MFS into a calvarial defect in a mouse model showed substantial bone regeneration. In conclusion, the uniform fabrication of microtissue constructs containing MSC spheroids with drug depots shows a potential to improve the performance of MSCs in tissue engineering.

T-cell engaging poly(lactic-co-glycolic acid) nanoparticles as a modular platform to induce a potent cytotoxic immunogenic response against PD-L1 overexpressing cancer.

Bispecific nanoparticles (NPs) are conjugated with two antibodies that enhance T cell cytotoxicity by sequentially targeting CD3 and tumor-specific proteins. This interaction redirects T cells to specific tumor antigens and activates them to lyse tumor cells by blocking two different signaling pathways simultaneously. This study developed NP-based bispecific T-cell engagers (nanoBiTEs), which are R848-loaded bispecific poly(lactic-co-glycolic acid) NPs decorated with anti-CD3 antibody targeting T cells and anti-PD-L1 antibody targeting PD-L1 ligands (bis-R848-PLGA-NPs). Bis-R848-PLGA-NPs enhance the immunogenic response in destroying cancer cells by restoring the T cell effector functions. These interactions allow T cells to come in close proximity to the tumor cells. Finally, the release of R848 from PLGA-NPs activates dendritic cells, enhancing T cell activation. In vitro results show maximum internalization of bis-R848-PLGA-NPs in SK-OV3 and B16F10 cell lines, attributed to high PD-L1 expression in both cells. Furthermore, bis-R848-PLGA-NPs-treated CD8+ T cells exhibit a significantly increased total amount of CD8+/CD25+, CD8+/CD69+, and cytokine expression that leads to the robust inhibition of PD-L1 expressed cancer cells. Additionally, tumor growth is significantly inhibited by bis-R848-PLGA-NPs in the B16F10 xenograft mouse model and significantly enhanced intratumoral infiltration of CD4+ and CD8+ T cells, as well as tumor-infiltrated cytokines.

Engineering of hybrid spheroids of mesenchymal stem cells and drug depots for immunomodulating effect in islet xenotransplantation.

Immunomodulation is an essential consideration for cell replacement procedures. Unfortunately, lifelong exposure to nonspecific systemic immunosuppression results in immunodeficiency and has toxic effects on nonimmune cells. Here, we engineered hybrid spheroids of mesenchymal stem cells (MSCs) with rapamycin-releasing poly(lactic-co-glycolic acid) microparticles (RAP-MPs) to prevent immune rejection of islet xenografts in diabetic C57BL/6 mice. Hybrid spheroids were rapidly formed by incubating cell-particle mixture in methylcellulose solution while maintaining high cell viability. RAP-MPs were uniformly distributed in hybrid spheroids and sustainably released RAP for ~3 weeks. Locoregional transplantation of hybrid spheroids containing low doses of RAP-MPs (200- to 4000-ng RAP per recipient) significantly prolonged islet survival times and promoted the generation of regional regulatory T cells. Enhanced programmed death-ligand 1 expression by MSCs was found to be responsible for the immunomodulatory performance of hybrid spheroids. Our results suggest that these hybrid spheroids offer a promising platform for the efficient use of MSCs in the transplantation field.

Methamphetamine induced neurotoxic diseases, molecular mechanism, and current treatment strategies.

Methamphetamine (MA) is a extremely addictive psychostimulant drug with a significant abuse potential. Long-term MA exposure can induce neurotoxic effects through oxidative stress, mitochondrial functional impairment, endoplasmic reticulum stress, the activation of astrocytes and microglial cells, axonal transport barriers, autophagy, and apoptosis. However, the molecular and cellular mechanisms underlying MA-induced neurotoxicity remain unclear. MA abuse increases the chances of developing neurotoxic conditions such as Parkinson's disease (PD), Alzheimer's disease (AD) and other neurotoxic diseases. MA increases the risk of PD by increasing the expression of alpha-synuclein (ASYN). Furthermore, MA abuse is linked to high chances of developing AD and subsequent neurodegeneration due to biological variations in the brain region or genetic and epigenetic variations. To date, there is no Food and Drug Administration (FDA)-approved therapy for MA-induced neurotoxicity, although many studies are being conducted to develop effective therapeutic strategies. Most current studies are now focused on developing therapies to diminish the neurotoxic effects of MA, based on the underlying mechanism of neurotoxicity. This review article highlights current research on several therapeutic techniques targeting multiple pathways to reduce the neurotoxic effects of MA in the brain, as well as the putative mechanism of MA-induced neurotoxicity.

Targeting Cancer Stem Cells: Therapeutic and diagnostic strategies by the virtue of nanoparticles.

Cancer stem cells (CSCs) are the subpopulation of cells present within a tumor with the properties of self-renewing, differentiating, and proliferating. Owing to the presence of ATP-binding cassette drug pumps and increased expression of anti-apoptotic proteins, the conventional chemotherapeutic agents have failed to eliminate CSCs resulting in relapse and resistance of cancer. Therefore, to obtain long-lasting clinical responses and avoid the recurrence of cancer, it is crucial to develop an efficient strategy targeting CSCs by either employing a differentiation therapy or specifically delivering drugs to CSCs. Several intracellular and extracellular cancer specific biomarkers are overexpressed by CSCs and are utilized as targets for the development of new approaches in the diagnosis and treatment of CSCs. Moreover, several nanostructured particles, alone or in combination with current treatment approaches, have been used to improve the detection, imaging, and targeting of CSCs, thus addressing the limitations of cancer therapies. Targeting CSC surface markers, stemness-related signaling pathways, and tumor microenvironmental signals has improved the detection and eradication of CSCs and, therefore, tumor diagnosis and treatment. This review summarizes a variety of promising nanoparticles targeting the surface biomarkers of CSCs for the detection and eradication of tumor-initiating stem cells, used in combination with other treatment regimens.

Enhancement of blood-brain barrier penetration and the neuroprotective effect of resveratrol.

Parkinson's disease (PD) is a debilitating neurodegenerative condition characterized by the loss of dopaminergic neurons within the substantia nigra. The specific molecular mechanisms through which PD-associated neuronal loss occurs remain unclear, and there is no available effective treatment against PD-related neurodegeneration. Resveratrol (RSV) has exhibited promising neuroprotective effects via antioxidant and anti-inflammatory activity. However, its poor bioavailability in the brain represents a challenge for its application in PD treatment. In this study, we synthesized RSV-loaded PLGA nanoparticles (RSV-PLGA-NPs) conjugated with lactoferrin (Lf) to enhance RSV diffusion into the brain and assessed whether this formulation improved the neuroprotective effects of RSV in experimental PD models. The Lf-conjugated RSV-PLGA-NPs (Lf-RSV-PLGA-NPs) exhibited enhanced internalization into SH-SY5Y and human brain microvascular endothelial cells as compared to RSV-PLGA-NPs and free RSV. Further, Lf-RSV-PLGA-NPs were more effective than RSV-PLGA-NPs and free RSV in attenuating the MPP+-induced generation of reactive oxygen species, reduction of mitochondrial membrane potential, and cell death. Importantly, Lf conjugation specifically increased the accumulation of RSV-PLGA-NPs in the brain as determined via bioluminescent imaging analyses. Our formulation substantially enhanced the neuroprotective effects of RSV in the MPTP-induced PD model. Hence, Lf-RSV-PLGA-NPs represent a promising tool for improving RSV bioavailability and neuroprotection within the brain.

Immunomodulation effect of mesenchymal stem cells in islet transplantation.

Mesenchymal stem cells (MSCs) therapy has brought a great enthusiasm to the treatment of various immune disorders, tissue regeneration and transplantation therapy. MSCs are being extensively investigated for their immunomodulatory actions. MSCs can deliver immunomodulatory signals to inhibit allogeneic T cell immune responses by downregulating pro-inflammatory cytokines and increasing regulatory cytokines and growth factors. Islet transplantation is a therapeutic alternative to the insulin therapy for the treatment of type 1 diabetes mellitus (T1DM). However, the acute loss of islets due to the lack of vasculature and hypoxic milieu in the immediate post-transplantation period may lead to treatment failure. Moreover, despite the use of potent immunosuppressive drugs, graft failure persists because of immunological rejection. Many in vitro and in vivo researches have demonstrated the multipotency of MSCs as a mediator of immunomodulation and a great approach for enhancement of islet engraftment. MSCs can interact with immune cells of the innate and adaptive immune systems via direct cell-cell contact or through secretomes containing numerous soluble growth and immunomodulatory factors or mitochondrial transfer. This review highlights the interactions between MSCs and different immune cells to mediate immunomodulatory functions along with the importance of MSCs therapy for the successful islet transplantation.

Recent progress in stimuli-responsive nanosystems for inducing immunogenic cell death.

Low immunogenicity and immunosuppressive tumor microenvironments are major hurdles in the application of cancer immunotherapy. To date, several immunogenic cell death (ICD) inducers have been reported to boost cancer immunotherapy by triggering ICD. ICD is characterized by the release of proinflammatory cytokines, danger-associated molecular patterns (DAMPs) and tumor associated antigens which will generate anticancer immunity by triggering adaptive immune cells. However, application of ICD inducers is limited due to severe toxicity issues and inefficient localization in the tumor microenvironment. To circumvent these challenges, stimuli-responsive nanoparticles have been exploited for improving cancer immunotherapy by limiting its toxicity. The combination of stimuli-responsive nanoparticles with an ICD inducer serves as a promising strategy for increasing the clinical applications of ICD induction in cancer immunotherapy. Here, we outline recent advances in ICD mediated by stimuli-responsive nanoparticles that may be near-infrared (NIR)-responsive, pH-responsive, redox responsive, pH and enzyme responsive, or pH and redox responsive, and evaluate their significant potential for successful clinical translation in cancer immunotherapy.

The impact of locally-delivered tacrolimus-releasing microspheres and polyethylene glycol-based islet surface modification on xenogeneic islet survival.

Pancreatic islet replacement therapy is an advanced choice for severe cases of type I diabetes. Nevertheless, extensive host immune response toward islet grafts remains a huge challenge for long-term graft function, and a lack of islet donors further increases the difficulties associated with upscaling this therapy. Mounting evidence suggests local delivery of immunosuppressive agents provides a feasible means of enhancing graft-protection. Among many immunosuppressants, tacrolimus (FK506) is one of the most potent interleukin-2 (IL-2)-mediated T-cell proliferation blockers. Here, we reported the effect of locally-delivered FK506-releasing PLGA microspheres (FK506-M) combined with polyethylene glycol (PEG)-based islet surface modification on xenogeneic islet survival in C57BL/6 mouse model. FK506-M was prepared using an emulsion method to a particle size of 10-40 µm and released FK506 over 40 days in vitro. Around 80% of the initial dose of FK506-M stably localized near transplanted islets, as observed under a bioimaging instrument and by immunofluorescence staining of islet grafts. Interestingly, FK506-M at very low-doses (equivalent to 150 to 2400 ng FK506 per recipient) was found to inhibit the infiltration of immune cells into grafts and reduce serum IL-1ß levels, thereby improving graft survival times dose-dependently. The PEGylation of islets alone was not enough to protect islets from early rejection. However, combined treatment with FK506-M additively prolonged xenograft survival. In conclusion, this study describes a safe, effective approach for translating a systemic exposure-free local drug delivery into clinical trials of islet transplantation.

Hypoxia-Mediated ROS Amplification Triggers Mitochondria-Mediated Apoptotic Cell Death via PD-L1/ROS-Responsive, Dual-Targeted, Drug-Laden Thioketal Nanoparticles.

Amalgamation of the reactive oxygen species (ROS)-responsive stimulus with nanoparticles has gained considerable interest owing to their high tumor specificity. Hypoxia plays a pivotal role in the acceleration of intracellular ROS production. Herein, we report the construction of a cancer cell (PD-L1)- and ROS-responsive, dual-targeted, temozolomide (TMZ)-laden nanosystem which offers a better anticancer effect in a hypoxic tumor microenvironment. A dual-targeted system boosted permeation in the cancer cells. Hypoxic conditions elevating the high ROS level accelerated the in situ release of TMZ from anti-PD-L1-TKNPs. Hyperaccumulated ROS engendered from TMZ caused oxidative damage leading to mitochondria-mediated apoptosis. TMZ fabricated in the multifunctional nanosystem (anti-PD-L1-TMZ-TKNPs) provided excellent tumor accumulation and retarded tumor growth under in vivo conditions. The elevated apoptosis effect with the activation of an apoptotic marker, DNA double-strand breakage marker, and downregulation of the angiogenesis marker in the tumor tissue following treatment with anti-PD-L1-TMZ-TKNPs exerts robust anticancer effect. Collectively, the nanoconstruct offers deep tumor permeation and high drug release and broadens the application of the ROS-responsive nanosystem for a successful anticancer effect.