The incorporation of new modalities into chemotherapy greatly enhances the anticancer efficacy combining the merits of each treatment, showing promising potentials in clinical translations. Herein, a hybrid nanomedicine (Au/FeMOF@CPT NPs) is fabricated using metal–organic framework (MOF) nanoparticles and gold nanoparticles (Au NPs) as building blocks for cancer chemo/chemodynamic therapy. MOF NPs are used as vehicles to encapsulate camptothecin (CPT), and the hybridization by Au NPs greatly improves the stability of the nanomedicine in a physiological environment. Triggered by the high concentration of phosphate inside the cancer cells, Au/FeMOF@CPT NPs effectively collapse after internalization, resulting in the complete drug release and activation of the cascade catalytic reactions. The intracellular glucose can be oxidized by Au NPs to produce hydrogen dioxide, which is further utilized as chemical fuel for the Fenton reaction, thus realizing the synergistic anticancer efficacy. Benefitting from the enhanced permeability and retention effect and sophisticated fabrications, the blood circulation time and tumor accumulation of Au/FeMOF@CPT NPs are significantly increased. In vivo results demonstrate that the combination of chemotherapy and chemodynamic therapy effectively suppresses the tumor growth, meantime the systemic toxicity of this nanomedicine is greatly avoided.
Background/Aims: The elucidation of the molecular mechanism of adipocyte differentiation in mesenchymal stem cells is of essential importance for the development of treatments for metabolic diseases, such as obesity and diabetes. Methods: The expression levels of miR-342-3p and carboxy-terminal binding protein 2 (CtBP2) were regulated by oligonucleotide transfection. Adipogenic differentiation was induced by adipogenic medium containing indomethacin, dexamethasone and 3-isobutyl-1-methylxanthine on day 12, as determined by Oil Red O staining and triglyceride concentration assay to assess intracellular lipid accumulation. The induction of adipocyte-specific transcription factors and markers was detected by qRT-PCR and western blot. The regulation of CtBP2 expression by miR-342-3p was determined by western blot, qRT-PCR, luciferase reporter assay, ChIP assay and functional experiments. Results: We revealed that miR-342-3p was enriched in the adipose tissue of obese mice, and its expression was significantly elevated during adipogenic differentiation in both human mesenchymal stem cells (hMSCs) and 3T3L1 cells. Using gain- and loss-of-function assays, we demonstrated that the overexpression of miR-342-3p markedly promoted the differentiation of hMSCs into an adipogenic lineage. Adipogenesis was significantly blocked by miR-342-3p downregulation. We identified and validated that CtBP2 was a direct target of miR-342-3p in this process. The effects of the inhibition of CtBP2 were similar to those of miR-342-5p overexpression on adipogenic differentiation, promoting the release of C/EBPα from CtBP2 binding. Conclusion: miR-342-3p is a powerful enhancer of the adipogenesis of human adipose-derived MSCs that acts by inhibiting CtBP2 and releasing the key adipogenic regulator C/EBPα from CtBP2 binding, subsequently activating the expression of adipogenic transcription factors and markers.
Hypoxic-ischemic brain damage (HIBD) is a common cause of infant death. The purpose of our research was to explore the immunoregulatory mechanism of placenta-derived mesenchymal stem cells (PD-MSCs) in HIBD treatment. Seven-day-old rat pups were randomly divided into HIBD, PD-MSC, fibroblast, and control groups. Forty-eight hours after HIBD induction, cells at a density of 5 × 104 cells/10 µl were injected into the cerebral tissue in the PD-MSC and fibroblast groups. The TNF-α, interleukin- 17 (IL-17), interferon-γ (IFN-γ), and IL-10 levels were detected through quantitative real-time polymerase chain reaction (RT-PCR) and enzyme-linked immunosorbent assay (ELISA). Regulatory T cell (Tregs) populations were detected through flow cytometry, and forkhead box P3 (Foxp3) was measured through western blot analysis. Behavioral tests and gross and pathological examinations showed that PD-MSC treatment exerted significantly stronger neuroprotective effects than the other treatments. The expression levels of pro-inflammatory cytokines were substantially upregulated after HI injury. Compared with fibroblast treatment, PD-MSC treatment inhibited the production of pro-inflammatory cytokines and increased the production of IL-10 in the ischemic hemispheres and peripheral blood serum (all P < 0.01). Flow cytometry results showed a notable increase in the number of Tregs within the spleen of the HIBD group. Moreover, the number of Tregs and the Foxp3 expression levels were higher in the PD-MSC treatment group than in the HIBD and fibroblast groups (all P < 0.01). Our research suggests that the mechanism of PD-MSC treatment for HIBD partially involves inflammatory response suppression.
Chronic exposure to high concentrations of hexavalent chromium [Cr(VI)] as sodium dichromate dihydrate (SDD) in drinking water induces duodenal tumors in mice, but the mode of action (MOA) for these tumors has been a subject of scientific debate. To evaluate the tumor-site-specific genotoxicity and cytotoxicity of SDD in the mouse small intestine, tissue pathology and cytogenetic damage were evaluated in duodenal crypt and villus enterocytes from B6C3F1 mice exposed to 0.3-520mg/L SDD in drinking water for 7 and 90 days. Allele-competitive blocker PCR (ACB-PCR) was used to investigate the induction of a sensitive, tumor-relevant mutation, specifically in vivo K-Ras codon 12 GAT mutation, in scraped duodenal epithelium following 90 days of drinking water exposure. Cytotoxicity was evident in the villus as disruption of cellular arrangement, desquamation, nuclear atypia and blunting. Following 90 days of treatment, aberrant nuclei, occurring primarily at villi tips, were significantly increased at ≥60mg/L SDD. However, in the crypt compartment, there were no dose-related effects on mitotic and apoptotic indices or the formation of aberrant nuclei indicating that Cr(VI)-induced cytotoxicity was limited to the villi. Cr(VI) caused a dose-dependent proliferative response in the duodenal crypt as evidenced by an increase in crypt area and increased number of crypt enterocytes. Spontaneous K-Ras codon 12 GAT mutations in untreated mice were higher than expected, in the range of 10(-2) to 10(-3); however no treatment-related trend in the K-Ras codon 12 GAT mutation was observed. The high spontaneous background K-Ras mutant frequency and Cr(VI) dose-related increases in crypt enterocyte proliferation, without dose-related increase in K-Ras mutant frequency, micronuclei formation, or change in mitotic or apoptotic indices, are consistent with a lack of genotoxicity in the crypt compartment, and a MOA involving accumulation of mutations late in carcinogenesis as a consequence of sustained regenerative proliferation.
These results demonstrate that PD-MSCs have neuroprotective effect during the treatment of HIBD and that the mechanism may be partly due to alleviating oxidative stress.
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