MDSC-targeted liposomal all-trans retinoic acid suppresses mMdscs and improves immunotherapy in HBV infection.

BACKGROUND: Myeloid-derived suppressor cells (MDSCs) are evolving as a prominent determinant in cancer occurrence and development and are functionally found to suppress T cells in cancer. Not much research is done regarding its involvement in viral infections. This research was designed to investigate the role of MDSCs in hepatitis B virus (HBV) infection and how targeting these cells with our novel all-trans retinoic acid encapsulated liposomal formulation could improve immunotherapy in C57BL/6 mice. METHODS: Ten micrograms (10 µg) of plasmid adeno-associated virus (pAAV/HBV 1.2, genotype A) was injected hydrodynamically via the tail vein of C57BL/6 mice. An all-trans retinoic acid encapsulated liposomal formulation (L-ATRA) with sustained release properties was used in combination with tenofovir disoproxil fumarate (TDF), a nucleotide analog reverse transcriptase inhibitor (nRTI) to treat the HBV infection. The L-ATRA formulation was given at a dose of 5 mg/kg intravenously (IV) twice a week. The TDF was given orally at 30 mg/kg daily. RESULTS: Our results revealed that L-ATRA suppresses MDSCs in HBV infected mice and enhanced T-cell proliferation in vitro. In vivo studies showed higher and improved immunotherapeutic effect in mice that received L-ATRA and TDF concurrently in comparison with the groups that received monotherapy. Lower HBV DNA copies, lower concentrations of HBsAg and HBeAg, lower levels of ALT and AST and less liver damage were seen in the mice that received the combination therapy of L-ATRA + TDF. CONCLUSIONS: In effect, targeting MDSCs with the combination of L-ATRA and TDF effectively reduced mMDSC and improved immunotherapy in the HBV infected mice. Targeting MDSCs could provide a breakthrough in the fight against hepatitis B virus infection.

Grassland biodiversity and ecosystem functions benefit more from cattle than sheep in mixed grazing: A meta-analysis.

Grasslands have been widely grazed for livestock production by cattle and sheep. However, previous studies have mainly focused on the impacts of single-species grazing on grassland biodiversity and ecosystem functions; the effects of mixed grazing of cattle and sheep remain largely unknown. We conducted a meta-analysis to examine the impacts of mixed grazing and analyzed the relative roles of cattle and sheep on grassland biodiversity and multiple ecosystem functions. Mixed grazing studies mainly originated from Europe, the USA, and China. Generally, cattle and sheep exhibited distinctive impacts on grassland biodiversity and functions in single-species and mixed grazing regimes. Cattle grazing alone increased plant diversity and soil organic carbon content (SOC), while sheep grazing alone had little impact. Compared to single-species grazing, mixed grazing generally increased plant density and richness of insect herbivores and decreased soil nematode richness, but did not alter plant biomass, soil nitrogen, or nematode abundance. Cattle in the mixed grazing regime increased plant diversity, biomasses of forbs and legumes, SOC, and liveweight gains of livestock. The mixed grazing impacts were further regulated by climate conditions, grazing intensity, and grazing duration. Our findings provide compelling evidence that mixed grazing benefits biodiversity, soil carbon sequestration, livestock production, and community structure of grasslands, and cattle are more influential than sheep in creating the benefits of mixed grazing for sustainable management of grasslands.

Linking leaf traits to the temporal stability of above- and belowground productivity under global change and land use scenarios in a semi-arid grassland of Inner Mongolia.

The biotic drivers for the temporal stability of aboveground net productivity (ANPP) in natural ecosystems are well understood. However, knowledge gaps still exist regarding the relative importance of biotic and abiotic drivers regulating the temporal stability of aboveground productivity (ANPP), belowground net productivity (BNPP), and community net productivity (NPP) under global change and land use scenarios. Thus, in this study, we aimed to study the effects of increased water and nitrogen availability on temporal stability of ANPP, BNPP, and NPP and underlying mechanisms at sites with different long-term grazing histories in typical grasslands of the Inner Mongolia. The results suggested that resource addition affected the ANPP stability, but it did not change the stability of BNPP and NPP, which were all mediated by grazing histories. Most importantly, our study further indicated that species asynchrony, primarily contributed to the stability of ANPP and NPP by weakening their variation, and species asynchrony was regulated directly by plant diversity-related variables and indirectly by soil variables which were affected by resource addition and grazing history. In addition, an increase of ANPP stimulated under resource addition was a secondary contributor to ANPP stability. Specifically, the community-weighted mean of specific leaf area (CWM SLA) regulated the ANPP stability indirectly by promoting species asynchrony, while functional diversity of leaf area and SLA both directly controlled the BNPP stability. Findings of our study demonstrate that different mechanisms drove temporal stability of above- and belowground productivity. Our study has important implications for maintaining the temporal stability of community productivity and for establishing sustainable management practices of semi-arid grasslands under global change and land use scenarios.

Solubilization and delivery of Ursolic-acid for modulating tumor microenvironment and regulatory T cell activities in cancer immunotherapy.

Ursolic acid (UA) is a potent triterpenoid compound found in plants and fruits with activities modulating key cell signaling pathways involving STATs, NF-κB, and TRAIL. But it's highly hydrophobic and very poorly soluble in nature. It had been prepared as nanocrystals, solid dispersion and loaded in nanoparticles but the achieved systemic exposure and circulation half-life were not ideal. We reported the development of UA-liposomes made by HPßCD assisted active loading. Compared to lipid suspensions of UA (Lipid-UA) with similar lipid composition, the novel process enabled the formation of UA-Ca crystalline structures inside the liposomes and therefore sustained release of UA in vivo. While the UA-liposomes were not generally toxic towards 4T1 triple negative breast cancer cells, they could effectively modulate CD4+CD25+Foxp3+ T cells from 4T1 tumor bearing mouse by inhibiting STAT5 phosphorylation and IL-10 secretion. In vivo administration of UA-liposomes at 10 mg/kg dose led to reduced numbers of myeloid derived suppressor cells (MDSCs) and regulatory T cells (Tregs) residing in tumor tissues. These changes signified the correction of the tumor mediated immune-suppressive microenvironment. The UA-liposomes treatment alone was already effective in deterring tumor growth. Such a formulation may be highly promising as an immunotherapy agent and be combined with chemotherapeutics or targeted drugs.

The Delivery of a Wnt Pathway Inhibitor Toward CSCs Requires Stable Liposome Encapsulation and Delayed Drug Release in Tumor Tissues.

The Wnt signaling pathway is involved in tumorigenesis and various stages of tumor progression, including the epithelial-mesenchymal transition, metastasis, and drug resistance. Many efforts have been made to develop drugs targeting this pathway. CGX1321 is a porcupine inhibitor that can effectively block Wnt ligand synthesis and is currently undergoing clinical trials. However, drugs targeting the Wnt pathway may frequently cause adverse events in normal tissues, such as the intestine and skin. Formulation of the drug inside liposomes could enable preferential drug delivery to solid tumor tissues and limit drug exposure in normal organs. We developed a strategy to stably encapsulate CGX1321 inside liposomes with minimal drug releases in circulation. The liposomal drugs were shown to interfere with the aberrant Wnt signaling specifically in tumor tissues, resulting in focused effects on LGR5+ CSCs (cancer stem cells), while sparing other cells from significant cytotoxicity. We showed it is feasible to use such a CSC elimination approach to treat malignant cancers prone to rapid progression using a LoVo tumor model as well as a GA007 patient derived xenograft (PDX) model. Nano drug delivery systems may be required for precision medicine in cancer therapy.

Identification of RSPO2 Fusion Mutations and Target Therapy Using a Porcupine Inhibitor.

Cancers are driven by a variety of somatic gene mutations and identifying these mutations enables the development of novel target drugs. We have sought to identify abnormalities in Wnt pathway-related genes that are sensitive to Wnt inhibitor treatment. We examined Patient Derived Xenograft (PDX) RNA samples and found new R-Spondin 2 (RSPO2) transcript fusions with the EMC2, PVT1 or HNF4G genes. These fusion events were identified in about 1.4% of the digestive system cancer samples. We then examined the oncogenic effects of the RSPO2-EMC2 fusion gene and confirmed that it can drive oncogenesis, sustain tumor growth and promote metastasis. Finally, we used a Wnt pathway Porcupine inhibitor CGX1321 to treat PDX mouse models containing RSPO2 fusion genes. All the RSPO2 fusion tumors responded to the treatment and stopped progression. Our data show that Wnt pathway inhibition could provide an effective treatment for cancers containing RSPO2 fusion. The RSPO2 fusion will serve as a good biomarker for screening patients to support clinical treatment of digestive system cancers using Wnt pathway inhibitors.

Tanshinone sensitized the antitumor effects of irradiation on laryngeal cancer via JNK pathway.

Laryngeal cancer is a common cancer occurred in the head and neck. Irradiation sensitivity is a problem affecting the treatment of laryngeal cancer. Tanshinone IIA has been reported to play an important role in treating multiple diseases; yet, whether Tanshinone IIA can be an irradiation sensitizer has not been reported. Clonogenic assay, annexin-V/propidium iodide double-staining assay, and Cell Counting Kit-8 assay were performed to detect cell survival, proliferation, apoptosis, and viability. Mouse laryngeal cancer xenograft model was established and subjected to tumor size analysis. Tanshinone IIA treatment increased the irradiation sensitivity of laryngeal cancer cells by reducing cell survival, viability and proliferation, and increasing cell apoptosis. Tanshinone IIA treatment increased the survival period of mice in the in vivo laryngeal cancer model, evidenced by decreased growth and weight of tumors, which was possibly mediated through the JNK pathway. Tanshinone IIA increases the sensitivity to irradiation in laryngeal cancer cells and in vivo laryngeal cancer model, suggesting that Tanshinone IIA can be a therapeutic antitumor agent for treating laryngeal cancer.

Selective Targeting and Eradication of LGR5+ Cancer Stem Cells Using RSPO-Conjugated Doxorubicin Liposomes.

Cancer stem cells (CSC) that may account for only a small fraction of tumor mass were found to play crucial roles during tumor initiating, progression, and metastasis. However, they are usually difficult to be treated and notoriously resilient to drug eradication. In this study, we aimed at the Wnt signaling characteristic of CSCs and designed a liposomal drug delivery system to target CSCs. Liposomes decorated with RSPO1 on the surface were constructed for specific interactions with the Wnt pathway coreceptor LGR5. Doxorubicin carried by the RSPO1-liposomes was more effective at lower concentrations than the same drug loaded in PEG-liposomes. More importantly, we showed using a patient-derived xenograft tumor model where LGR5+ CSCs coexisted with LGR5- cells, the RSPO1-liposomes were able to access more CSC cells and deliver the drug specifically and efficiently. Such a focused effect in eradicating LGR5+ cells led to massive tumor tissue necrosis and growth inhibition even when only a fraction of the conventional drug dose was used. These data clearly demonstrated the advantages of CSC-targeted drug delivery and would support the development of such approaches as a new cancer treatment strategy. Mol Cancer Ther; 17(7); 1475-85. ©2018 AACR.

[Evaluation of simulated mandibular models in skill training of implantology for dental undergraduates].

PURPOSE: To explore the effects of simulated mandibular models in skill training of implantology for dental undergraduate. METHODS: Pre-clinical teaching of oral implantology was implemented on simulation models for 51 undergraduates of grade 2013. Each undergraduate inserted a dental implant and took an impression in the simulation model under the teacher＇s guidance. After the training course, the scores were evaluated both objectively and subjectively. RESULTS: An average score of 91.6 was obtained in the course of oral implantology on simulated mandibular models. All students appreciated the teaching methods. They believed that training on simulation models could improve their learning interest and arouse their learning motivation. CONCLUSIONS: Simulated mandibular models are good tools in training of oral implantology for dental undergraduates education, which is worthy of wide application.

[Effects of platelet-rich fibrin extract on MC3T3-E1 cell].

OBJECTIVE: To evaluate the effect of platelet-rich fibrin extract (PRFe) on proliferation and differentiation and F-actin cytoskeleton of osteoblasts. METHODS: The experimental group used the α-minimum essential medium (α-MEM) containing PRFe (10% fetal bovine serum), and the control group used the α-MEM (10% fetal bovine serum). The number of the osteoblasts at 1st, 3rd, 5th d was detected by methyl thiazolyl tetrazolium (MTT) assay, and the differentiation of osteoblast at 1st, 3rd, 5th,7 th d detected by the activity of alkaline phosphatase (ALP).The alizarin red dye was used to observe the number of calcium nodus at 14th, 21st d. The F-actin cytoskeleton was evaluated by confocal laser scanning microscope(CLSM) at 3rd,6th,9th,12th h. The level of osteogenetic biomarkers osteocalcin (OCN) and core-binding factor α1(Cbfα1) at 3rd,7th d were quantified by real-time PCR. RESULTS: A significant increase of absorbance at 1st, 3rd, 5th d was showed in experimental group (0.336 ± 0.011, 0.571 ± 0.039, 0.787 ± 0.050) compared to control group (0.300 ± 0.021, 0.387 ± 0.040, 0.527 ± 0.034) (P < 0.05). The absorbance of experimental group at 1st, 3rd, 5th, 7th d (0.146 ± 0.014, 0.199 ± 0.017, 0.390 ± 0.020, 0.492 ± 0.019) was significantly higher than that of control group (0.115 ± 0.014, 0.145 ± 0.015, 0.190 ± 0.015, 0.230 ± 0.026) (P < 0.05). The integrated absorbance of the calcium nodus in experimental group at 14th, 21st d (22.119 ± 3.694, 31.528 ± 3.162) was significantly higher than in control group (8.498 ± 2.041, 15.162 ± 2.526) (P < 0.05). The Cbfα1 and OCN gene expression in experimental group was higher than in control group (P < 0.05). CONCLUSIONS: PRFe could enhance the proliferation and differentiation of osteoblasts and promote the spread of F-actin cytoskeleton.

[Expression of receptor activator nuclear factor kappa B ligand and osteoprotegerin in peri-implant soft tissue and bone tissue].

OBJECTIVE: To study mRNA expression of receptor activator nuclear factor kappa B ligand (RANKL) and its decoy receptor, osteoprotegerin (OPG) in peri-implant tissue during unloading period. METHODS: An animal model of dental implant was established in 6 male Beagle dogs of 1-2 years old. Bone remodeling was tested at 3, 7, 15, 30, 60 and 90 days since the placement of implants. RANKL and OPG mRNA expression were quantified by real-time polymerase chain reaction (PCR). Then mandibular bones were taken out and the morphological changes were observed by X-ray, bone tissue was tested by immunohistochemistry stain. RESULTS: The most prominent period of bone remodeling occurred at 7th day after the placement of implants. The expression of RANKL and OPG increased in a time-dependent manner in both soft and hard tissue. After 7 days they gradually decreased. CONCLUSION: RANKL and OPG can express in soft tissue, and the changing tendency is consistent with the change of bone remodeling, it indicates that RANKL and OPG play an important role in the bone remodeling.