IL-27p28 specifically regulates MHC II expression in macrophages through CIITA.

Antigen-presenting cells (APCs) constantly express major histocompatibility complex II (MHC II), including macrophages and dendritic cells (DCs) which deliver antigens to CD4+ T cells and play an important role in adaptive immunity. The expression of MHC II is controlled by the transcriptional coactivator CIITA. Interleukin-27 (IL-27), a newly discovered IL-12 family cytokine, is composed of p28 and EBI3 subunits. In this study, we used IL-27p28 conditional knock-out mice to investigate the regulatory effects of IL-27p28 on macrophage polarization and the expression of MHC II in macrophages. We found that MHC II expression was upregulated in the bone marrow-derived and peritoneal exudate macrophages (BMDMs; PEMs) from IL-27p28-deficient mice, with their inflammation regulating function unaffected. We also demonstrated that in the APCs, IL-27p28 selectively regulated MHC II expression in macrophages but not in dendritic cells. During Pseudomonas aeruginosa (P. aeruginosa) reinfection, higher survival rate, bacterial clearance, and ratio of CD4+/CD8+ T cells in the spleen during the specific immune phase were observed in IL-27p28 defect mice, as well as an increased MHC II expression in alveolar macrophages (AMs). But these did not occur in the first infection. For the first time we discovered that IL-27p28 specifically regulates the expression of MHC II in macrophages by regulating CIITA, while its absence enhances antigen presentation and adaptive immunity against P. aeruginosa.

Whole exome sequencing with a focus on cardiac disease-associated genes in families of sudden unexplained deaths in Yunnan, southwest of China.

OBJECTIVES: To explore the causes of sudden unexpected death (SUD) and to search for high-risk people, whole exome sequencing (WES) was performed in families with SUDs.  METHODS: Whole exome sequencing of 25 people from 14 SUD families were screened based on cardiac disease-associated gene variants, and their echocardiograms and electrocardiograms (ECG) were also examined. The protein function of mutated genes was predicted by SIFT, PolyPhen2 and Mutation Assessor. RESULTS: In the group of 25 people from 14 SUD families, 49 single nucleotide variants (SNVs) of cardiac disease-associated genes were found and verified by Sanger sequencing. 29 SNVs of 14 cardiac disorder-related genes were predicted as pathogens by software. Among them, 7 SNVs carried by two or more members were found in 5 families, including SCN5A (c.3577C > T), IRX4 (c.230A > G), LDB3 (c.2104 T > G), MYH6 (c.3G > A), MYH6 (c.3928 T > C), TTN (c.80987C > T) and TTN (c.8069C > T). 25 ECGs were collected. In summary, 4 people had J-point elevation, 2 people had long QT syndrome (LQTS), 4 people had prolonged QT interval, 3 people had T-wave changes, 3 people had sinus tachycardia, 4 people had sinus bradycardia, 4 people had left side of QRS electrical axis, and 3 people had P wave broadening. Echocardiographic results showed that 1 person had atrial septal defect, 1 person had tricuspid regurgitation, and 2 people had left ventricular diastolic dysfunction. CONCLUSIONS: Of the 14 heart disease-associated genes in 14 SUDs families, there are 7 possible pathological SNVS may be associated with SUDs. Our results indicate that people with ECG abnormalities, such as prolonged QT interval, ST segment changes, T-wave change and carrying the above 7 SNVs, should be the focus of prevention of sudden death.

Mesenchymal stem cell-derived extracellular vesicles attenuate tPA-induced blood-brain barrier disruption in murine ischemic stroke models.

Intracerebral hemorrhage following blood-brain barrier (BBB) disruption resulting from thrombolysis of ischemic stroke with tissue plasminogen activator (tPA) remains a critical clinical problem. Mesenchymal stem cell-derived extracellular vesicles (MSC-EVs) are promising nanotherapeutic agents that have the potential to repair the BBB after ischemic stroke; however, whether they can attenuate BBB disruption and hemorrhagic transformation after tPA thrombolysis is largely unknown. Here, we observed that MSC-EVs efficiently passed through the BBB and selectively accumulated in injured brain regions in ischemic stroke model mice in real time using aggregation-induced emission luminogens (AIEgens), which exhibit better tracking ability than the commercially available tracer DiR. Moreover, tPA administration promoted the homing of MSC-EVs to the ischemic brain and increased the uptake of MSC-EVs by astrocytes. Furthermore, the accumulated MSC-EVs attenuated the tPA-induced disruption of BBB integrity and alleviated hemorrhage by inhibiting astrocyte activation and inflammation. Mechanistically, miR-125b-5p delivered by MSC-EVs played an indispensable role in maintaining BBB integrity by targeting Toll-like receptor 4 (TLR4) and inhibiting nuclear transcription factor-kappaB (NF-κB) signaling in astrocytes. This study provides a noninvasive method for real-time tracking of MSC-EVs in the ischemic brain after tPA treatment and highlights the potential of MSC-EVs as thrombolytic adjuvants for ischemic stroke. STATEMENT OF SIGNIFICANCE: Although tPA thrombolysis is the most effective pharmaceutical strategy for acute ischemic stroke, its clinical application and therapeutic efficacy are challenged by tPA-induced BBB disruption and hemorrhagic transformation. Our study demonstrated that MSC-EVs can act as an attractive thrombolytic adjuvant to repair the BBB and improve thrombolysis in a mouse ischemic stroke model. Notably, by labeling MSC-EVs with AIEgens, we achieved accurate real-time imaging of MSC-EVs in the ischemic brain and therapeutic visualization. MSC-EVs inhibit astrocyte activation and associated inflammation through miR-125b-5p/TLR4/NF-κB pathway. Consequently, we revealed that MSC-EVs combined with tPA thrombolysis may be a promising approach for the treatment of ischemic stroke in clinical setting.

Functional analysis of HADH c.99C>G shows that the variant causes the proliferation of pancreatic islets and leu-sensitive hyperinsulinaemia.

A novel missense variant (NM_005327.7: c.99C>G, p.Ile33Met) was discovered in 3-hydroxyacyl-CoA dehydrogenase (HADH), which is involved in congenital hyperinsulinism (CHI). This variant may be damaging or deleterious, as assessed using protein prediction software. This study aimed at the impact of this variant on islets and if it caused the leu-sensitive insulin secretion. The adenoassociated virus containing the HADH missense variant (p.Ile33Met), wild-type (WT) HADH or empty vector (EV) was constructed, and the rats were infected with it. Three weeks after the transfection, 15 rats were dissected to observe the effect of the variant on the islet tissue. Then we treated the remaining rats with leucine or sodium carboxymethyl cellulose (CMC-Na) by gavage and drew blood from the rat tail vein to detect the variations in blood glucose, serum insulin and serum glucagon. Further, we dissected the rats to observe the fluctuation of insulin and glucagon contents in pancreatic islets under the combined action of leucine and p.Ile33Met. Insulin and glucagon were observed in the islet tissue under an inverted fluorescence microscope, serum insulin and glucagon were detected by ELISA, and the blood glucose value was determined using a Roche glucometer. The positive area and average gray value of islet fluorescence pictures were analysed using the software Image J (USA). Rats expressing p.Ile33Met showed significantly higher insulin and glucagon content, as well as the islet area, compared to WT and EV rats. Moreover, after intragastric administration of leucine, the serum insulin content of the variant rats increased but the blood sugar level decreased significantly. Meanwhile, there was an appreciable decrease in the insulin content in rat pancreatic islet tissues. Our results suggest that the variant NM_005327.7: c.99C>G promotes the proliferation of pancreatic islets, enhances the secretion of insulin, and induces leu-sensitive hyperinsulinaemia.

Macrophage-Membrane-Camouflaged Nonviral Gene Vectors for the Treatment of Multidrug-Resistant Bacterial Sepsis.

Sepsis is a life-threatening disease caused by systemic bacterial infections, with high morbidity and mortality worldwide. As the standard treatment for sepsis, antibiotic therapy faces the challenge of impaired macrophages and drug-resistant bacteria. In this study, we developed a membrane-camouflaged metal-organic framework (MOF) system for plasmid DNA (pDNA) delivery to combat sepsis. The antimicrobial gene LL37 was efficiently encapsulated in the pH-sensitive MOF, and the nanoparticles were decorated with macrophage membranes in a compatible manner. Macrophage membrane coating allows targeted delivery of LL37 to macrophages and creates macrophage factories for the continuous generation of antimicrobial peptides. Compared to naked nanoparticles, primary bone marrow mesenchymal macrophage membrane-modified nanoparticles greatly improved the survival rate of immunodeficient septic mice through the synergistic effect of efficient gene therapy and inflammatory cytokine sequestration. This study demonstrates an effective membrane biomimetic strategy for efficiently delivering pDNA, offering an excellent option for overcoming sepsis.

Biosynthetic Dendritic Cell-Exocytosed Aggregation-Induced Emission Nanoparticles for Synergistic Photodynamic Immunotherapy.

Dendritic cell (DC)-derived small extracellular vesicles (DEVs) are recognized as a highly promising alternative to DC vaccines; however, the clinical testing of DEV-based immunotherapy has shown limited therapeutic efficacy. Herein, we develop a straightforward strategy in which DCs serve as a cell reactor to exocytose high-efficient DEV-mimicking aggregation-induced emission (AIE) nanoparticles (DEV-AIE NPs) at a scaled-up yield for synergistic photodynamic immunotherapy. Exocytosed DEV-AIE NPs inherit not only the immune-modulation proteins from parental DCs, enabling T cell activation, but also the loaded AIE-photosensitizer MBPN-TCyP, inducing superior immunogenic cell death (ICD) by selectively accumulating in the mitochondria of tumor cells. Eventually, DEV-AIE synergistic photodynamic immunotherapy elicits dramatic immune responses and efficient eradication of primary tumors, distant tumors, and tumor metastases. In addition, cancer stem cells (CSCs) in 4T1 and CT26 solid tumors were significantly inhibited by the immune functional DEV-AIE NPs. Our work presents a facile method for the cellular generation of EV-biomimetic NPs and demonstrates that the integration of DEVs and AIE photosensitizers is a powerful direction for the production of clinical anticancer nanovaccines.

The efficacy of low-power cumulative high-intensity focused ultrasound treatment for recurrent desmoid tumor.

BACKGROUND: Desmoid tumors are rare neoplasms that are locally invasive. However, optimal treatment strategies for recurrent desmoid tumors remain controversial. High-intensity focused ultrasound (HIFU) has been reported as a noninvasive modality for treating recurrent desmoid tumors. However, its efficacy against massive desmoid tumors or those with complex anatomies remains unclear. METHODS: We developed a new therapeutic strategy called low-power cumulative HIFU and applied it to treat recurrent desmoid tumors. RESULTS: We retrospectively collected data from 91 patients with recurrent desmoid tumors who underwent low-power cumulative HIFU treatment after surgical treatment failure. The mean ablation proportion of the HIFU treatment was 69.5%, and the objective response rate was 47.3%. The 5-year estimated progression-free survival rate for these patients was 69.3%. CONCLUSION: Low-power cumulative HIFU treatment could achieve significant efficacy and long-term control of recurrent desmoid tumors.

Coassembly of hypoxia-sensitive macrocyclic amphiphiles and extracellular vesicles for targeted kidney injury imaging and therapy.

BACKGROUND: Hypoxia is a major contributor to global kidney diseases. Targeting hypoxia is a promising therapeutic option against both acute kidney injury and chronic kidney disease; however, an effective strategy that can achieve simultaneous targeted kidney hypoxia imaging and therapy has yet to be established. Herein, we fabricated a unique nano-sized hypoxia-sensitive coassembly (Pc/C5A@EVs) via molecular recognition and self-assembly, which is composed of the macrocyclic amphiphile C5A, the commercial dye sulfonated aluminum phthalocyanine (Pc) and mesenchymal stem cell-excreted extracellular vesicles (MSC-EVs). RESULTS: In murine models of unilateral or bilateral ischemia/reperfusion injury, MSC-EVs protected the Pc/C5A complex from immune metabolism, prolonged the circulation time of the complex, and specifically led Pc/C5A to hypoxic kidneys via surface integrin receptor α4ß1 and αLß2, where Pc/C5A released the near-infrared fluorescence of Pc and achieved enhanced hypoxia-sensitive imaging. Meanwhile, the coassembly significantly recovered kidney function by attenuating cell apoptosis, inhibiting the progression of renal fibrosis and reducing tubulointerstitial inflammation. Mechanistically, the Pc/C5A coassembly induced M1-to-M2 macrophage transition by inhibiting the HIF-1α expression in hypoxic renal tubular epithelial cells (TECs) and downstream NF-κB signaling pathway to exert their regenerative effects. CONCLUSION: This synergetic nanoscale coassembly with great translational potential provides a novel strategy for precise kidney hypoxia diagnosis and efficient kidney injury treatment. Furthermore, our strategy of coassembling exogenous macrocyclic receptors with endogenous cell-derived membranous structures may offer a functional platform to address multiple clinical needs.

Smart Self-Assembly Amphiphilic Cyclopeptide-Dye for Near-Infrared Window-II Imaging.

Development of novel nanomaterials for disease theranostics represents an important direction in chemistry and precision medicine. Fluorescent molecular probes in the second near-infrared window (NIR-II, 1000-1700 nm) show high promise because of their exceptional high detection sensitivity, resolution, and deep imaging depth. Here, a sharp pH-sensitive self-assembling cyclopeptide-dye, SIMM1000, as a smart nanoprobe for NIR-II imaging of diseases in living animals, is reported. This small molecule assembled nanoprobe exhibits smart properties by responding to a sharp decrease of pH in the tumor microenvironment (pH 7.0 to 6.8), aggregating from small nanoprobe (80 nm at pH 7.0) into large nanoparticles (>500 nm at pH 6.8) with ≈20-30 times enhanced fluorescence compared with the non-self-assembled CH-4T. It yields micrometer-scale resolution in blood vessel imaging and high contrast and resolution in bone and tumor imaging in mice. Because of its self-aggregation in acidic tumor microenvironments in situ, SIMM1000 exhibits high tumor accumulation and extremely long tumor retention (>19 days), while being excretable from normal tissues and safe. This smart self-assembling small molecule strategy can shift the paradigm of designing new nanomaterials for molecular imaging and drug development.

The efficacy of a new high-intensity focused ultrasound therapy for metastatic pancreatic cancer.

PURPOSE: To compare the survival benefit, pain control and safety of low-power cumulative and traditional high-intensity focused ultrasound (HIFU) for metastatic pancreatic cancer. METHOD: We retrospectively analyzed 55 patients with metastatic pancreatic cancer who received HIFU treatment between January 2008 and April 2014 in our department. 23 patients received low-power cumulative HIFU treatment (L group), 32 received the traditional HIFU treatment (T group). Performance status, cancer-related pain and serum biochemistry results were assessed before and after treatment. All patients were followed up until death. The survival rate and adverse events of the two groups were compared. RESULTS: The baseline characteristics of the two groups were generally well balanced (p > 0.05). The average KPS score after treatment was significantly improved in both groups compared with the baseline score. 36 patients exhibited tumor-related pain at baseline. The pain response rate was significantly higher in the L group (92.3%) than in the T group (52.2%) (p = 0.025). The median overall survival (OS) for the L group was 7.0 months, which was significantly longer than that of the T group (p = 0.000). The 3-month and 6-month survival rates were higher in the L group. The adverse events in both groups included abdominal pain, elevated C-reactive protein (CRP) and elevated amylase. The incidence was lower in the L group than in the T group. CONCLUSION: Compared with traditional HIFU treatment, low-power cumulative HIFU treatment showed a significantly higher pain relief rate and survival benefit with a better safety profile in patients with metastatic pancreatic cancer.

In Vivo Tracking of Mesenchymal Stem Cell-Derived Extracellular Vesicles Improving Mitochondrial Function in Renal Ischemia-Reperfusion Injury.

Extracellular vesicles (EVs) released by mesenchymal stem cells (MSCs) have exhibited regenerative capability in animal models of ischemia-reperfusion (I/R) acute kidney injury (AKI) and are considered as potential alternatives to direct MSC therapy. However, real-time in vivo imaging of MSC-EVs in renal I/R injury has yet to be established. Renal intracellular targets of MSC-EVs responsible for their regenerative effects also remain elusive. Here, we report that we real-time observed MSC-EVs specifically accumulated in the injured kidney and were taken up by renal proximal tubular epithelia cells (TECs) via DPA-SCP with aggregation-induced emission (AIE) characteristics. DPA-SCP precisely tracked the fate of MSC-EVs in a renal I/R injury mouse model for 72 h and exhibited superior spatiotemporal resolution and tracking ability to popular commercially available EV tracker PKH26. Further analysis revealed that the accumulated MSC-EVs stimulated mitochondrial antioxidant defense and ATP production via activating the Keap1-Nrf2 signaling pathway, which protected TECs against oxidative insult by reducing mitochondrial fragmentation, normalizing mitochondrial membrane potential, and increasing mitochondrial DNA copy number. Increased microRNA-200a-3p expression in renal TECs induced by MSC-EVs was identified as a regulatory mechanism contributing to the protective actions on mitochondria as well as stimulating the renal signal transduction pathways. In conclusion, MSC-EVs accumulated in the renal tubules during renal I/R injury and promoted the recovery of kidney function via activating the Keap1-Nrf2 signaling pathway and enhancing mitochondrial function of TECs. DPA-SCP with AIE characteristics allows noninvasive and precise in vivo visualization of MSC-EVs in kidney repair.

In Vivo Real-Time Imaging of Extracellular Vesicles in Liver Regeneration via Aggregation-Induced Emission Luminogens.

Extracellular vesicles (EVs) attract much attention in liver pathology because they regulate cell-cell communication and many pathophysiological events by transferring their cargos. Monitoring and understanding the in vivo fate and therapeutic capacity of these EVs is critical for the development and optimization of EV-based diagnosis and therapy. Herein, we demonstrate the use of an aggregation-induced emission luminogen, DPA-SCP, for the real-time tracking of EVs derived from human placenta-derived mesenchymal stem cells (MSCs) and their therapeutic effects in a mouse acute liver injury (ALI) model. In vitro, DPA-SCP does not alter the inherent characteristics of MSC-derived EVs and shows extremely low toxicity. Moreover, DPA-SCP exhibited superior labeling efficiency and tracking capability to the most popular commercial EV trackers, PKH26 and DiI. In vivo, DPA-SCP precisely and quantitatively tracked the behaviors of EVs for 7 days in the mouse ALI model without influencing their regenerative capacity and therapeutic efficacy. The therapeutic effects of EVs may attribute to their ability for reducing inflammatory cell infiltration, enhancing cell survival and antiapoptotic effects. In conclusion, DPA-SCP with an AIE signature serves as a favorable and safe tracker for in vivo real-time imaging of EVs in liver regeneration.

Self-assembled GFFYK peptide hydrogel enhances the therapeutic efficacy of mesenchymal stem cells in a mouse hindlimb ischemia model.

Mesenchymal stem cell (MSC) transplantation has emerged as a very promising strategy for the treatments of peripheral artery disease (PAD). However, MSC-based therapies are limited by low cell retention and survival rate in the ischemic zone. Small molecular (SM) hydrogels have shown attractive abilities to enhance the therapeutic effects of human MSCs via promoting their proliferation or maintaining their differentiation potential. Here, we designed and synthesized a new bioactive and biocompatible hydrogel, Nap-GFFYK-Thiol, using disulfide bonds as cleavable linkers to control the molecular self-assembly and we hypothesized this hydrogel could enhance the retention and engraftment of human placenta-derived MSCs (hP-MSCs) in a mouse ischemic hindlimb model. In vitro results demonstrated that the Nap-GFFYK-Thiol hydrogel increased cell viability through paracrine effects. Moreover, it enhanced the proangiogenic and anti-apoptotic effects of hP-MSCs. In vivo, Nap-GFFYK-Thiol hydrogel improved the hP-MSC retention in the murine ischemic hindlimb model as visualized by bioluminescence imaging. Furthermore, cotransplantation of hP-MSCs with hydrogel improved blood perfusion, leading to superior limb salvage. These therapeutic effects may attribute to reduced inflammatory cell infiltration, enhanced angiogenesis as well as suppressed collagen deposition. In conclusion, the Nap-GFFYK-Thiol hydrogel fabricated using disulfide bonds as cleavable linkers serves as an artificial niche for promoting hP-MSC survival and proangiogenic factor secretion in PAD therapy and thereby provide an alternative strategy for PAD therapy. STATEMENT OF SIGNIFICANCE: Although several phase I/II clinical trials of MSC-based treatments for critical limb ischemia (CLI) are ongoing, MSC-based therapies are still challenged by the low quality and quantity of cells in the ischemic zone, especially in cases of extensive or irreversible damage. Hydrogels have favorable biocompatibility and safety records in the medical field. In the current study, we engineered a new bioactive and biocompatible hydrogel, Nap-GFFYK-Thiol, using disulfide bonds as cleavable linkers to enhance the therapeutic efficacy of human placenta-derived MSCs (hP-MSCs) in mouse limb ischemia model. Notably, Nap-GFFYK-Thiol hydrogel acts as an artificial niche for promoting hP-MSC survival and proangiogenic factor secretion in PAD therapy, which further promoted the restoration of blood perfusion and regeneration of muscle cells. Considering the proangiogenic effect of Nap-GFFYK-Thiol on hP-MSCs, our results may provide a new strategy for the treatment of PAD.

Stat3 activation is critical for pluripotency maintenance.

Signal transducer and activator of transcription 3 (Stat3) is a cytoplasmic transcription with many important functions, including regulation of cell proliferation, differentiation, survival, angiogenesis, and immune response. Besides, it plays critical roles in regulating the pluripotency. With the ability of self-renewal and differentiation, embryonic stem (ES) cells provide an unlimited source for cell transplantation. ES cells can maintain its undifferentiated state with leukemia inhibitory factor, the role which is achieved by the activation of the Stat3 pathway. Moreover, Stat3 activation is necessary for the naïve state maintenance of the ES cells and somatic stem cells reprogramming. This study presents an overview of the critical roles of Stat3 activation in the pluripotency maintenance of ES cells, somatic cell reprogramming, and naïve-primed pluripotent states conversion of ES cells.

Enhanced Therapeutic Effects of Mesenchymal Stem Cell-Derived Exosomes with an Injectable Hydrogel for Hindlimb Ischemia Treatment.

Mesenchymal stem cell (MSC)-derived exosomes have been recognized as new candidates for cell-free treatment of various diseases. However, maintaining the retention and stability of exosomes over time in vivo after transplantation is a major challenge in the clinical application of MSC-derived exosomes. Here, we investigated if human placenta-derived MSC-derived exosomes incorporated with chitosan hydrogel could boost the retention and stability of exosomes and further enhance their therapeutic effects. Our results demonstrated that chitosan hydrogel notably increased the stability of proteins and microRNAs in exosomes, as well as augmented the retention of exosomes in vivo as confirmed by Gaussia luciferase imaging. In addition, we assessed endothelium-protective and proangiogenesis abilities of hydrogel-incorporated exosomes in vitro. Meanwhile, we evaluated the therapeutic function of hydrogel-incorporated exosomes in a murine model of hindlimb ischemia. Our data demonstrated that chitosan hydrogel could enhance the retention and stability of exosomes and further augment the therapeutic effects for hindlimb ischemia as revealed by firefly luciferase imaging of angiogenesis. The strategy used in this study may facilitate the development of easy and effective approaches for assessing and enhancing the therapeutic effects of stem cell-derived exosomes.

Investigation of Newly Prepared Biodegradable 32P-chromic Phosphate-polylactide-co-glycolide Seeds and Their Therapeutic Response Evaluation for Glioma Brachytherapy.

32P high-dose rate brachytherapy allows high-dose radiation delivery to target lesions with less damage to adjacent tissues. The early evaluation of its therapeutic effect on tumours is vital for the optimization of treatment regimes. The most commonly used 32P-CP colloid tends to leak with blind therapeutic area after intratumour injection. We prepared 32P-chromic phosphate-polylactide-co-glycolide (32P-CP-PLGA) seeds with biodegradable PLGA as a framework and investigated their characteristics in vitro and in vivo. We also evaluated the therapeutic effect of 32P-CP-PLGA brachytherapy for glioma with the integrin αvß3-targeted radiotracer 68Ga-3PRGD2. 32P-CP-PLGA seeds (seed group, SG, 185 MBq) and 32P-CP colloid (colloid group, CG, 18.5 MBq) were implanted or injected into human glioma xenografts in nude mice. Scanning electron microscopy (SEM) of the seeds, micro-SPECT imaging, and biodistribution studies were performed at different time points. The tumour volume was measured using a caliper, and 68Ga-3PRGD2 micro-PET-CT imaging was performed to evaluate the therapeutic effect after 32P intratumour administration. The delayed release of 32P-CP was observed with biodegradation of vehicle PLGA. Intratumoural effective half-life of 32P-CP in the SG (13.3 ± 0.3) d was longer than that in the CG (10.4 ± 0.3) d (P < 0.05), with liver appearance in the CG on SPECT. A radioactivity gradient developed inside the tumour in the SG, as confirmed by micro-SPECT and SEM. Tumour uptake of 68Ga-3PRGD2 displayed a significant increase on day 0.5 in the SG and decreased earlier (on day 2) than the volume reduction (on day 8). Thus, 32P-CP-PLGA seeds, controlling the release of entrapped 32P-CP particles, are promising for glioma brachytherapy, and 68Ga-3PRGD2 imaging shows potential for early response evaluation of 32P-CP-PLGA seeds brachytherapy.

Preparation of 68Ga-PSMA-11 with a Synthesis Module for Micro PET-CT Imaging of PSMA Expression during Prostate Cancer Progression.

Objective: To synthesize 68Ga-Glu-urea-Lys(Ahx)-HBED-CC (68Ga-PSMA-11) with a synthesis module and investigate PET-CT imaging to monitor PSMA expression during prostate cancer (PCa) progression and tumor growth in mice bearing subcutaneous PCa xenografts. Method: The radiochemical purity and stability of 68Ga-PSMA-11 were determined via radio-HPLC. The PCa cell lines of different PSMA expression levels (PC3, VCAP±, CWR22RV1+, and LNCaP++) were selected to mimic the PCa progression. 68Ga-PSMA-11 biodistribution was studied by dissection method and in vivo imaging with micro PET-CT. The expression levels of PSMA in tumor cells and tissues were analyzed by immunofluorescence, flow cytometry, and western blot. The correlation between PSMA expression and radio-uptake was also evaluated. 2-PMPA preadministration served as a block group. Results: The radiochemical purity of 68Ga-PSMA-11 was 99.6 ± 0.1% and stable in vitro for 2 h. The equilibrium binding constant (Kd) of 68Ga-PSMA-11 to LNCaP, CWR22Rv1, PC-3, and VCAP cells was 4.3 ± 0.8 nM, 16.4 ± 1.3 nM, 225.3 ± 20.8 nM, and 125.6 ± 13.1 nM, respectively. Results of tumor uptake (% ID and % ID/g or % ID/cm3) of 68Ga-PSMA-11 in biodistribution and micro PET imaging were LNCaP > CWR22RV1 > PC-3 and VCAP due to different PSMA expression levels. It was confirmed by flow cytometry, western blot, and immunofluorescence. Tumor uptake (% ID/cm3) of 68Ga-PSMA-11 increased with the tumor anatomical volume in quadratic polynomial fashion and reached the peak (when tumor volume was 0.5 cm3) earlier than tumor uptake (% ID). Tumor uptake (% ID/cm3) of 68Ga-PSMA-11 based on functional volume correlated well with the PSMA expression in a linear manner (y = 9.35x + 2.59, R2 = 0.8924, and p < 0.0001); however, low dose 2-PMPA causes rapid renal clearance of increased tumor/kidney uptake of 68Ga-PSMA-11. Conclusions: The 68Ga-PSMA-11 PET-CT imaging could invasively evaluate PSMA expression during PCa progression and tumor growth with % ID/cm3 (based on functional volume) as an important index. Low dose 2-PMPA preadministration might be a choice to decrease kidney uptake of 68Ga-PSMA-11.

Molecular Imaging of Tumor Angiogenesis and Therapeutic Effects with Dual Bioluminescence.

BACKGROUND: Angiogenesis is critical for the growth of tumor by supplying nutrients and oxygen that exacerbates the metastasis and progression of cancer. Noninvasive imaging of angiogenesis during the tumor therapeutic processes may provide novel opportunities for image-guided tumor management. OBJECTIVE: Here, we want to develop a mouse animal model for assessing cancer progression and angiogenesis in the same individuals by molecular imaging. METHODS: Breast cancer model was developed with mouse breast cancer cell line 4T1 carrying a reporter system encoding a triple fusion (TF) reporter gene consisting of renilla luciferase (Rluc), red fluorescent protein (RFP) and herpes simplex virus truncated thymidine kinase (HSV-ttk) in transgenic mice, which expressed firefly luciferase (Fluc) under the promoter of vascular endothelial growth factor receptor 2 (Vegfr2-luc). The mice were subsequently treated with ganciclovir (GCV) and the tumor angiogenesis was tracked by Fluc imaging and the growth status of tumor was monitored by imaging of Rluc simultaneously. CONCLUSION: Overall, this traceable breast cancer model can simultaneously image the tumor growth and angiogenesis in single individual, which may facilitate a better understanding the mechanisms of angiogenesis in the progression and regression of tumor.

Stat3 phosphorylation is required for embryonic stem cells ground state maintenance in 2i culture media.

Embryonic stem cells (ES cells) can be maintained its undifferentiated state with feeder cells or LIF, which can activate Jak/Stat3 pathway. Recently, it has been reported a new culture condition comprising serum-free medium with ERK and GSK3ß inhibitors (2i) could drive ES cells into a state of pluripotency more like inner cell mass (ICM) in mouse blastocysts called ground state. However, although 2i could sustain ES cells self-renewal, LIF is routinely added. The roles of Stat3 activation are still unclear now. Here we investigated whether Jak/Stat3 might also contribute to the induction of ground state pluripotency. We introduced a lentiviral construct with 7-repeat Stat3-binding sequence to drive Renilla luciferase into ES cells, which can be used as a reporter to detect Stat3 activation by noninvasive bioluminescence imaging. Using this ES cells, we investigated the role of Stat3 activation in ground state maintenance. The results showed that Stat3 could be activated by 2i. Stattic, a chemical inhibitor of Stat3 phosphorylation, could effectively inhibit Stat3 activation in ES cells. When Stat3 activation was suppressed, ground state related genes were down regulated, and ES cells could not be maintained the ground state pluripotency even in 2i medium. All of these results indicate Stat3 activation is required in ground state maintenance.

Embryonic stem cell preconditioned microenvironment suppresses tumorigenic properties in breast cancer.

BACKGROUND: Microenvironment is being increasingly recognized as a critical determinant in tumor progression and metastasis. However, the appropriate regulatory mechanism to maintain the normal balance between differentiation and self-renewal of the cancer cell in microenvironment is not well known. METHODS: 4T1 breast cancer cells were treated with embryonic stem (ES) cell conditioned medium which was collected from mouse ES cells. Inhibition of tumor cell growth was based on the reduction of cell proliferation and viability, and inhibition of aggressive properties of tumor cells were examined using the wound-healing and mammosphere assays. The expression of stem cell-associated genes was detected by quantitative RT-PCR. RESULTS: We used a real-time imaging system to investigate the effect of the mouse ES cell microenvironment on aggressive breast cancer cells in vitro and in vivo. Exposure of breast cancer cells in mouse ES cell conditioned medium resulted in inhibition of growth, migration, metastasis, and angiogenesis of cancer cells. For many tumors, aggressive properties were tightly related to Stat3 signaling activation. We specifically discovered that the ES cell microenvironment sufficiently suppressed Stat3 signaling pathway activation in aggressive tumor cells, leading to a reduction in tumorigenesis and invasiveness. CONCLUSIONS: We identified important functions of Stat3 and their implications for antitumor effects of ES cell conditioned medium. Some factors secreted by ES cells could efficiently suppress Stat3 pathway activation in breast cancer cells, and were then involved in cancer cell growth, survival, invasion, and migration. This study may act as a platform to understand tumor cell plasticity and may offer new therapeutic strategies to inhibit breast cancer progression.