The bidirectional relationship between periodontitis and diabetes: New prospects for stem cell-derived exosomes.

Periodontitis and diabetes have a bidirectional link, making therapeutic treatment of periodontitis and diabetes challenging. Numerous factors, including microbes, inflammatory cytokines, immune cell activity, glucose levels, and metabolic disorders, contribute to the bidirectional relationship of periodontitis and diabetes. Basic periodontal treatment, medication, surgical treatment, and combined treatment are the most widely used treatments, but their efficacy are limited. Because of their capacity to support bone remodeling and tissue regeneration and restoration, reduce blood glucose levels, restore islet function, and ameliorate local and systemic inflammation, stem cell-derived exosomes have emerged as a possible therapeutic. In this review, we summarize the utilization of stem cell-derived exosomes in periodontitis and diabetes，discuss their potential mechanisms in periodontitis and diabetes bidirectional promoters. It provides some theoretical basis for using stem cell-derived exosomes to regulate the bidirectional link between periodontitis and diabetes.

Potential angiogenic, immunomodulatory, and antifibrotic effects of mesenchymal stem cell-derived extracellular vesicles in systemic sclerosis.

Systemic sclerosis (SSc) is an intricate systemic autoimmune disease with pathological features such as vascular injury, immune dysregulation, and extensive fibrosis of the skin and multiple organs. Treatment options are limited; however, recently, mesenchymal stem cell-derived extracellular vesicles (MSC-EVs) have been acknowledged in preclinical and clinical trials as being useful in treating autoimmune diseases and are likely superior to MSCs alone. Recent research has also shown that MSC-EVs can ameliorate SSc and the pathological changes in vasculopathy, immune dysfunction, and fibrosis. This review summarizes the therapeutic effects of MSC-EVs on SSc and the mechanisms that have been discovered to provide a theoretical basis for future studies on the role of MSC-EVs in treating SSc.

Retraction: NF-κB inhibition promotes apoptosis in androgen-independent prostate cancer cells by the photothermal effect via the IκBα/AR signaling pathway.

Retraction of 'NF-κB inhibition promotes apoptosis in androgen-independent prostate cancer cells by the photothermal effect via the IκBα/AR signaling pathway' by Chenfei Kong et al., Biomat. Sci., 2019, 7, 2559-2570, https://doi.org/10.1039/C8BM01007B.

B16 Membrane-Coated Vesicles for Combined Photodynamic Therapy and Immunotherapy Shift Immune Microenvironment of Melanoma.

Introduction: Coating of nanomedicine with cell membranes has attracted increasing attention as it can boost biocompatibility and improve the efficiency of treatment. Herein, we prepared innovative tumor cell-membrane-coated vesicles based on photodynamic therapy (PDT) drug indocyanine green (ICG) and explore the effect on melanoma in vitro and in vivo. Methods: ICG was coated with B16 cell membranes (I@BM NVs) by sonication and extrusion, and the morphological characteristics of I@BM NVs were evaluated by transmission electron microscopy (TEM) and NP-tracking analysis. Homologous cellular uptake was evaluated by flow cytometry (FCM) after staining by DiD dye. Cellular cytotoxicity was evaluated by cell counting kit-8 assay and the anti-tumor effect in vitro was assessed by FCM and western blotting. The anti-tumor effect in vivo was evaluated in a B16 xenograft model in mice. The tumor micro-environment was investigated by FCM and real-time PCR. Results: The vesicles are stable and uniform in nature, and show strong homologous targeting in vivo and in vitro. The vesicles can generate reactive oxygen species to induce apoptosis of B16 cells under near-infrared irradiation. Furthermore, the I@BM NVs induce a significant anti-tumor response in vivo, and perform better with respect to both tumor growth inhibition and lifespan extension. Analysis of immunocytes in the tumor microenvironment showed significant reductions in numbers of myeloid-derived suppressor cells and tumor-associated M2 macrophages in mice in the I@BM NVs group. This was accompanied by significant increases in numbers of M1 macrophages and proliferative CD4+/CD8+ T cells. Expression levels of IFN-γ and IL-2 increased in the I@BM NVs group, while expression of TGF-ß and IL-10 decreased. Conclusion: The results show that the I@BM NVs are feasible drugs for the treatment of melanoma by inducing cell apoptosis under NIR and shifting the immunosuppressive tumor microenvironment in vivo.

Current Knowledge Regarding the Interaction Between Oral Bone Metabolic Disorders and Diabetes Mellitus.

Diabetes mellitus, a major chronic disease affecting human health, has been increasing in prevalence in recent years. Diabetes mellitus can cause bone metabolic disorders in patients, leading to osteoporosis, a higher risk of traumatic fracture, and other bone diseases. Bone metabolic disorders in the oral cavity principally manifest as periodontitis, loss of alveolar bone, and failure of implant osseointegration. In recent years, numerous studies have shown that there is a complex interaction between bone metabolic disorders and diabetes mellitus. This paper reviews the adverse effects of diabetes on oral bone metabolism disorders such as alveolar osteoporosis and bone loss in patients with periodontitis, discusses the potential mechanisms of diabetic bone loss, and suggests potential ways to prevent and treat oral bone loss in patients with diabetes mellitus.

Synthesis of dual functional procaine-derived carbon dots for bioimaging and anticancer therapy.

Aim: Procaine-derived carbon dots, termed P-dots, expectedly offer both fluorescent biomarker function and anticancer activity. Materials & methods: P-dots were synthesized by condensing procaine, citric acid and ethylenediamine via hydrothermal synthesis and characterized by transmission electron microscopy, Fourier transform infrared spectroscopy and x-ray photoelectron spectroscopy. The cellular uptake behavior and the bioimaging performance of P-dots were assessed by confocal laser scanning microscopy. Their antitumor activity was evaluated using the CCK-8 assays and in vivo antitumor experiments, and the underlying mechanism was evaluated by flow cytometry and western blotting. Results: P-dots exhibited excellent luminescence properties suitable for bioimaging and considerable anticancer activity associated with caspase-3-related cell apoptosis. Conclusion: The synthesized procaine-derived carbon dots presented a dual function consisting of bioimaging and anticancer activity, which may enable their implementation as safe and effective clinical nanotherapeutics.

NF-κB inhibition promotes apoptosis in androgen-independent prostate cancer cells by the photothermal effect via the IκBα/AR signaling pathway.

The photothermal response of nanomaterials provides a basis for many biomedical applications, including diagnosis (e.g., biosensor and photoacoustic imaging) and treatment (e.g., drug delivery and photothermal therapy). The use of nano-materials for cancer phototherapy (solid tumor ablation) can cause cell necrosis and apoptosis. However, photothermal effects using the same material can differ among tumor cell types, and the molecular mechanisms underlying these differences are not clear. We used polydopamine (PDA)-coated branched Au-Ag nanoparticles (Au-Ag@PDA NPs) for the photothermal treatment of two prostate cancer cell lines. The therapeutic effect was evaluated by CCK8, flow cytometry, and expression analyses of related genes by western blotting. Photothermal therapy resulted in oxidative stress in prostate cancer cells and activated the mitochondrial-related apoptosis pathway, increasing the Bax expression. In addition, we observed a greater photothermal treatment effect on the androgen-dependent cells LNCaP than the androgen-independent cells DU145. Pretreatment with an inhibitor of the NF-κB signaling pathway (BAY 11-7082) enhanced the expression of BAX in the DU145 cells and increased the sensitivity of the cells to the heat treatment of Au-Ag@PDA NPs both in vitro and in vivo. Our findings explain the differences in the observed effects of photothermal therapy and provide the direction for further improvements to this strategy.

Inhibition of Autophagy Promoted Apoptosis and Suppressed Growth of Hepatocellular Carcinoma Upon Photothermal Exposure.

Photothermal therapy (PTT) is a recently developed and promising strategy for the treatment of hepatocellular carcinoma (HCC). However, apoptosis has been extensively investigated as the mechanism of the underlying effect of PTT on cancer to date. Here, we explored alternative mechanisms of these therapeutic effects, including the activation of cell-cycle arrest and autophagy during PTT in addition to apoptosis under mild temperature. We treated the HCC cell line HepG2 with polydopamine (PDA)-coated branched Au-Ag nanoparticles at various concentrations along with PTT using an 808-nm laser. Apoptosis was evaluated based on flow cytometry, western blot analysis of apoptosis related proteins (BAX, BCL2, caspase 3), Hoechst staining, and TUNEL staining. To explore the role of autophagy, we treated cells with the autophagy inhibitor chloroquine diphosphate. Enhancement of apoptosis by PTT with nanoparticle treatment was observed after autophagy was inhibited. Moreover, inhibition of autophagy markedly enhance the suppression of tumor growth in vivo in a HepG2 mouse xenograft model. These results suggest that further exploration of the mechanism of PTT can help guide its clinical application, and that autophagy inhibition combined with PTT could be a promising strategy for HCC treatment.

Fusion with mesenchymal stem cells differentially affects tumorigenic and metastatic abilities of lung cancer cells.

Cell fusion plays a crucial role in cancer progression and leads to massive aberrant changes in chromosome and gene expression involved in tumor metastasis. Cancer cells can fuse with many cell types, including stromal cells, epithelial cells, macrophages, and endothelial cells. Mesenchymal stem cells (MSCs) have been reported to migrate and incorporate into tumor sites during cancer progression. However, the underlying mechanism of stem cell fusion in tumor metastasis has not been fully deciphered. In this research, we established a cell fusion model between lung cancer cells and MSCs in vitro. We found that the hybrid cells showed enhanced metastatic capacity with increased expression of MMP-2 and MMP-9, whereas the proliferation ability was inhibited and cell cycle was blocked in the G0 /G1 phase with elevated expression of p21, p27, and p53. Moreover, the hybrid cells lost epithelial morphology and exhibited an epithelial-mesenchymal transition (EMT) change with downregulation of E-cadherin and upregulation of N-cadherin, Vimentin, α-SMA and Fibronectin1. Meanwhile, the expressions of EMT transcription factors, including Snail1, Slug, Twist1, Zeb1, and Zeb2, were also increased in hybrid cells. More important, the fusion hybrids acquired stem cell-like properties, which exhibited increased expression stem cell transcription factors Oct4, Sox2, Nanog, Kif4 as well as Bmi1. Taken together, our results suggested that cell fusion between lung cancer cells and MSCs offered enhanced metastatic capacity and characteristics of cancer stem cell by undergoing EMT. This study will contribute to explaning the origin of lung cancer stem cells and to elucidate the role of cell fusion in cancer metastasis.

Polydopamine-coated Au-Ag nanoparticle-guided photothermal colorectal cancer therapy through multiple cell death pathways.

Nanoparticles are emerging as a new therapeutic modality due to their high stability, precise targeting, and high biocompatibility. Branched Au-Ag nanoparticles with polydopamine coating (Au-Ag@PDA) have strong near-infrared absorbance and no cytotoxicity but high photothermal conversion efficiency. However, the photothermal activity of Au-Ag@PDA in vivo and in vitro has not been reported yet, and the mechanism underlying the effects of photothermal nanomaterials is not clear. Therefore, in this study, the colorectal cancer cell line HCT-116 and nude mice xenografts were used to observe the photothermal effects of Au-Ag@PDA in vivo and in vitro. The results suggest that Au-Ag@PDA NPs significantly inhibited cell proliferation and induced apoptosis in colorectal cancer cells. Moreover, Au-Ag@PDA NP-mediated photothermal therapy inhibited the growth of tumors at doses of 50 and 100 µg in vivo. The mechanisms through which Au-Ag@PDA NPs induced colorectal cancer cell death involved multiple pathways, including caspase-dependent and -independent apoptosis, mitochondrial damage, lysosomal membrane permeability, and autophagy. Thus, our findings suggest that Au-Ag@PDA NPs could be used as potential antitumor agents for photothermal ablation of colorectal cancer cells.

Photothermal exposure of polydopamine-coated branched Au-Ag nanoparticles induces cell cycle arrest, apoptosis, and autophagy in human bladder cancer cells.

PURPOSE: Polydopamine-coated branched Au-Ag nanoparticles (Au-Ag@PDA NPs) exhibit good structural stability, biocompatibility, and photothermal performance, along with potential anticancer efficacy. Here, we investigated the cytotoxicity of Au-Ag@PDA NPs against human bladder cancer cells (T24 cells) in vitro and in vivo, as well as the underlying molecular mechanisms of photothermal therapy-induced T24 cell death. MATERIALS AND METHODS: T24 cells were treated with different doses of Au-Ag@PDA NPs followed by 808 nm laser irradiation, and the effects on cell proliferation, cell cycle, apoptosis, and autophagy were analyzed. To confirm the mechanisms of inhibition, real-time PCR and Western blot analysis were used to evaluate markers of cell cycle, apoptosis, autophagy, and the AKT/ERK signaling pathway. Moreover, we evaluated the effects of the treatment on mitochondrial membrane potential and ROS generation to confirm the underlying mechanisms of inhibition. Finally, we tested the T24 tumor inhibitory effects of Au-Ag@PDA NPs plus laser irradiation in vivo using a xenograft mouse model. RESULTS: Au-Ag@PDA NPs, with appropriate laser irradiation, dramatically inhibited the proliferation of T24 cells, altered the cell cycle distribution by increasing the proportion of cells in the S phase, induced cell apoptosis by activating the mitochondria-mediated intrinsic pathway, and triggered a robust autophagy response in T24 cells. Moreover, Au-Ag@PDA NPs decreased the expression of phosphorylated AKT and ERK and promoted the production of ROS that function upstream of apoptosis and autophagy. In addition, Au-Ag@PDA NP-mediated photothermolysis also significantly suppressed tumor growth in vivo. CONCLUSION: This preclinical study can provide a mechanistic basis for Au-Ag@PDA NP-mediated photothermal therapy toward promotion of this method in the clinical treatment of bladder cancer.

Syndecan-1 suppresses epithelial-mesenchymal transition and migration in human oral cancer cells.

Epithelial-mesenchymal transition (EMT) is one of the major processes that contribute to the occurrence of cancer metastasis. EMT has been associated with the development of oral cancer. Syndecan­1 (SDC1) is a key cell­surface adhesion molecule and its expression level inversely correlates with tumor differentiation and prognosis. In the present study, we aimed to determine the role of SDC1 in oral cancer progression and investigate the molecular mechanisms through which SDC1 regulates the EMT and invasiveness of oral cancer cells. We demonstrated that basal SDC1 expression levels were lower in four oral cancer cell lines (KB, Tca8113, ACC2 and CAL­27), than in normal human periodontal ligament fibroblasts. Ectopic overexpression of SDC1 resulted in morphological transformation, decreased expression of EMT­associated markers, as well as decreased migration, invasiveness and proliferation of oral cancer cells. In contrast, downregulation of the expression of SDC1 caused the opposite results. Furthermore, the knockdown of endogenous SDC1 activated the extracellular signal­regulated kinase (ERK) cascade, upregulated the expression of Snail and inhibited the expression of E­cadherin. In conclusion, our findings revealed that SDC1 suppressed EMT via the modulation of the ERK signaling pathway that, in turn, negatively affected the invasiveness of human oral cancer cells. Our results provided useful evidence about the potential use of SDC1 as a molecular target for therapeutic interventions in human oral cancer.

Hypoxia regulates IL-17A secretion from nasal polyp epithelial cells.

Hypoxia creates a microenvironment conducive to polypogenesis by regulating immune responses of the nasal polyp (NP) epithelium. We explored the immunocompetence of NP and control epithelial cells in response to hypoxia, to investigate potential relationships with polypogenesis. Three groups of tissue samples were collected: inferior turbinate (IT)and NP from individuals with chronic rhinosinusitis with NPs (CRSwNP), and control IT. A positive relationship was detected between HIF1α, HIF2α protein expression in epithelial cells and endoscope score in NP samples, while there was a negative correlation between HIF1α expression and degree of eosinophil infiltration. Epithelial IL-17A expression was lower in NPs than in IT samples from either controls or patients with CRSwNP. Primary human nasal epithelial cells were cultured under hypoxic or normoxic conditions. Enzyme-linked immunosorbent assays demonstrated decreased IL-17A expression upon prolonged exposure to hypoxia in both IT and NP samples from patients with CRSwNP, while IL-17A increased in control IT epithelial cells; correlation and time-dependency were observed between HIF1α and IL-17A expression in both IT and NP samples from patients with CRSwNP. These observations suggest that hypoxia is involved in the pathogenesis of NPs through regulation of IL-17A secretion and HIF1α and HIF2α expression in the NP epithelium.

EGFR-targeted delivery of DOX-loaded Fe3O4@ polydopamine multifunctional nanocomposites for MRI and antitumor chemo-photothermal therapy.

Multifunctional nanocomposites that have multiple therapeutic functions together with real-time imaging capabilities have attracted intensive concerns in the diagnosis and treatment of cancer. This study developed epidermal growth factor receptor (EGFR) antibody-directed polydopamine-coated Fe3O4 nanoparticles (Fe3O4@PDA NPs) for magnetic resonance imaging and antitumor chemo-photothermal therapy. The synthesized Fe3O4@PDA-PEG-EGFR-DOX NPs revealed high storage capacity for doxorubicin (DOX) and high photothermal conversion efficiency. The cell viability assay of Fe3O4@PDA-PEG-EGFR NPs indicated that Fe3O4@ PDA-PEG-EGFR NPs had no cell cytotoxicity. However, Fe3O4@PDA-PEG-EGFR-DOX NPs could significantly decrease cell viability (~5% of remaining cell viability) because of both photothermal ablation and near-infrared light-triggered DOX release. Meanwhile, the EGFR-targeted Fe3O4@PDA-PEG-EGFR-DOX NPs significantly inhibited the growth of tumors, showing a prominent in vivo synergistic antitumor effect. This study demonstrated the potential of using Fe3O4@PDA NPs for combined cancer chemo-photothermal therapy with increased efficacy.

FOXC1, a target of polycomb, inhibits metastasis of breast cancer cells.

Polycomb group (PcG) proteins have recently been shown related to cancer development. The PcG protein EZH2 is involved in progression of prostate and breast cancers, and has been identified as a molecular marker in breast cancer. Nevertheless, the molecular mechanism by which PcG proteins regulate cancer progression and malignant metastasis is still unclear. PcG proteins methylate H3K27 in undifferentiated epithelial cells, resulting in the repression of differentiation genes such as HOX. FOXC1 is a member of the Forkhead box transcription factor family, which plays an important role in differentiation, and is involved in eye development. We discovered in this study that the expression of FOXC1 gene was negatively correlated to that of PcG genes, i.e., Bmi1, EZH2, and SUZ12, in MCF-7 and MDA-MB-231 cells. To investigate the regulatory effects of PcG proteins on FOXC1 gene, the two cell lines were transfected with either expression plasmids or siRNA plasmids of Bmi1, EZH2, and SUZ12, and we found that PcGs, especially EZH2, could repress the transcription of FOXC1 gene. Chromatin immunoprecipitation (ChIP) assay showed that histone methylation and acetylation modifications played critical roles in this regulatory process. When FOXC1 was stably transfected into MDA-MB-231 cells, the migration and invasion of the cells were repressed. Moreover, the tumorigenicity and the spontaneous metastatic capability regulated by FOXC1 were determined by using an orthotropic xenograft tumor model of athymic mice with the FOXC1-MDA-MB-231HM and the GFP-MDA-MB-231HM cells, and the results showed that FOXC1 in MDA-MB-231HM cells inhibited migration and invasion in vitro and reduced the pulmonary metastasis in vivo. Data presented in this report contribute to the understanding of the mechanisms by which EZH2 participates in tumor development.

NEDD9 is a positive regulator of epithelial-mesenchymal transition and promotes invasion in aggressive breast cancer.

Epithelial to mesenchymal transition (EMT) plays an important role in many biological processes. The latest studies revealed that aggressive breast cancer, especially the triple-negative breast cancer (TNBC) subtype was frequently associated with apparent EMT, but the mechanisms are still unclear. NEDD9/HEF1/Cas-L is a member of the Cas protein family and was identified as a metastasis marker in multiple cancer types. In this study, we wished to discern the role of NEDD9 in breast cancer progression and to investigate the molecular mechanism by which NEDD9 regulates EMT and promotes invasion in triple-negative breast cancer. We showed that expression of NEDD9 was frequently upregulated in TNBC cell lines, and in aggressive breast tumors, especially in TNBC subtype. Knockdown of endogenous NEDD9 reduced the migration, invasion and proliferation of TNBC cells. Moreover, ectopic overexpression of NEDD9 in mammary epithelial cells led to a string of events including the trigger of EMT, activation of ERK signaling, increase of several EMT-inducing transcription factors and promotion of their interactions with the E-cadherin promoter. Data presented in this report contribute to the understanding of the mechanisms by which NEDD9 promotes EMT, and provide useful clues to the evaluation of the potential of NEDD9 as a responsive molecular target for TNBC chemotherapy.

Discovery of polyoxometalate-based HDAC inhibitors with profound anticancer activity in vitro and in vivo.

We obtained 5 positive novel histone deacetylase inhibitors (HDACIs) from a polyoxometalate (POM) library by using a cell-based screening system targeting the p21 gene promoter. Among them, PAC-320, a new tri-organic-tin-substitute germanotungstate, displayed remarkable extracellular inhibitory activity. Meanwhile, the crystal structure of PAC-320 was characterized by X-ray crystallography. PAC-320 could stably exist under physiological conditions as revealed by UV spectrum, CV and TG. PAC-320 possessed a strong inhibitory effect to intracellular HDAC activity. More significantly, PAC-320 inhibited the growth of a variety of cancer cells, and exhibited remarkable anticancer effect in a hepatocarcinoma H22 cell mice model. This study revealed, for the first time, that the HDAC inhibitory activity is a mechanism by which POMs exert their anticancer effect.

DNMT3a plays a role in switches between doxorubicin-induced senescence and apoptosis of colorectal cancer cells.

The DNA-damaging drug doxorubicin (Dox) induces cell senescence at concentrations significantly lower than those required for induction of apoptosis. At low Dox concentrations, tumor suppressor p53 is activated, which enhances the expression of p21(Waf1/Cip1) (p21). At high concentrations, Dox activates p53 leading to apoptosis without enhancing p21 expression. The underlying mechanisms and factors that govern the differential effects of Dox in inducing senescence and apoptosis are unclear. Here, we report that the DNA methyltransferase (DNMT) DNMT3a was upregulated by Dox especially at concentrations that induced apoptosis in HCT116 colorectal cancer cells, and this process was regulated by p53. Meanwhile, p21 expression was significantly upregulated at senescence-inducing concentrations and kept low on treatment with apoptosis-inducing concentrations of Dox. The differential expression of DNMT3a and p21 in response to Dox suggests that DNMT3a may be a key factor in switches between Dox-induced senescence and apoptosis. Moreover, when DNMT3a was silenced, treatment of HCT116 cells with apoptosis-inducing concentration of Dox increased the percentage of cells undergoing senescence, accompanied by upregulation of p21. Contrarily, senescence-inducing concentration of Dox promoted apoptosis rate, and p21 expression was repressed. Surprisingly, no changes in DNA methylation status at p21 promoter were detected at either ranges of Dox, although DNMT3a and HDAC1 were recruited to p21 promoter at apoptosis-inducing Dox concentration, where they were present in the same complex. Overall, these data demonstrate that DNMT3a impacts the expression of p21 and plays a role in determining the Dox-induced senescence and apoptosis in HCT116 cells.

Genome-wide analysis of histone H3 lysine9 modifications in human mesenchymal stem cell osteogenic differentiation.

Mesenchymal stem cells (MSCs) possess self-renewal and multi-lineage differentiation potentials. It has been established that epigenetic mechanisms such as histone modifications could be critical for determining the fate of stem cells. In this study, full human genome promoter microarrays and expression microarrays were used to explore the roles of histone modifications (H3K9Ac and H3K9Me2) upon the induction of MSC osteogenic differentiation. Our results revealed that the enrichment of H3K9Ac was decreased globally at the gene promoters, whereas the number of promoters enriched with H3K9Me2 was increased evidently upon osteogenic induction. By a combined analysis of data from both ChIP-on-chip and expression microarrays, a number of differentially expressed genes regulated by H3K9Ac and/or H3K9Me2 were identified, implicating their roles in several biological events, such as cell cycle withdraw and cytoskeleton reconstruction that were essential to differentiation process. In addition, our results showed that the vitamin D receptor played a trans-repression role via alternations of H3K9Ac and H3K9Me2 upon MSC osteogenic differentiation. Data from this study suggested that gene activation and silencing controlled by changes of H3K9Ac and H3K9Me2, respectively, were crucial to MSC osteogenic differentiation.