Jiao Chen

Interferon-γ-induced PD-L1 surface expression on human oral squamous carcinoma via PKD2 signal pathway

Many cells located in the tumor microenvironment function to protect or promote the ability of tumor cells to escape immune destruction. Previous studies have shown that programmed death ligand-1 (PD-L1), a ligand of the B7 superfamily, is expressed on a series of human tumors and can inhibit anti-tumor immune responses. Interferon-γ (IFN-γ), a cytokine produced and secreted by inflammatory cells in the tumor microenvironment, is a main stimulator of PD-L1 expression in tumor cells. Making clear the mechanism of IFN-γ induced the expression of PD-L1 on tumor cells that is benefit to find a way to inhibit the function of PD-L1 and improve cancer cell-reactive immune responses. Herein, we have identified protein kinase D isoform 2 (PKD2) as an important regulator of PD-L1 expression on human oral squamous carcinoma cells induced by IFN-γ. IFN-γ induced the expression of PD-L1 and PKD2 in human oral squamous carcinoma Tca8113 in both time and dose dependent manner. The expression of PD-L1 was decreased significantly after PKD2 knockdown with shRNA/siRNA interference or PKD chemical inhibitor following induction with IFN-γ. The apoptosis of CD8(+) T cell which is induced by tumor cells via PD-1/PD-L1 pathway was significantly decreased, as a result, the anti-tumor effects of tumor antigen specific T cell were increased in vivo. Together, these data combined with our previous results, indicate PKD2 as an important target candidate for tumor biotherapy. Inhibition of PKD2 activation not only inhibits PD-L1 expression and promotes an anti-tumor effect, but also decreases drug resistance in chemotherapy.

PKD2 mediates multi-drug resistance in breast cancer cells through modulation of P-glycoprotein expression

Multi-drug resistance (MDR) represents a major obstacle for chemotherapeutic treatment of a wide variety of human cancers. Increased expression of drug efflux pumps, such as the P-glycoprotein (P-gp) have been linked to development of MDR. Herein, we have identified protein kinase D isoform 2 (PKD2) as an important regulator of MDR and P-gp expression in paclitaxel-treated breast cancer cell lines. PKD2 was expressed with the highest phosphorylated activation status in the MDA-MB-231 cell line. MDA-MB-231 cells were also found to exhibit the highest level of resistance to an array of chemotherapeutic drugs. To further characterize the relationship between PKD2 activation and MDR, we next focused on the effects of the chemotherapeutic agent paclitaxel in MDA-MB-231 cells. Treatment with paclitaxel was shown to induce both PKD2 phosphorylation and P-gp expression in a time-dependent manner. Importantly, shRNA-mediated knockdown of PKD2 in MDA-MB-231 cells resulted in a significant decrease in resistance to paclitaxel, evident as significant decreases in both the IC(50) value and the resistance index (RI). Concurrent with the decrease in drug resistance, paclitaxel-induced expression of P-gp was also significantly reduced in PKD knockdown cells. These results indicate that PKD2 is required for paclitaxel-induced MDR and expression of P-gp. Therefore, modulation of PKD2 activity represents an attractive therapeutic strategy for improvement of the clinical effectiveness of chemotherapy.

Inflammation promotes oral squamous carcinoma immune evasion via induced programmed death ligand-1 surface expression.

The association between inflammation and cancer provides a new target for tumor biotherapy. The inflammatory cells and molecules within the tumor microenvironment have decisive dual roles in antitumor immunity and immune evasion. In the present study, phytohemagglutinin (PHA) was used to stimulate peripheral blood mononuclear cells (PBMCs) to simulate the tumor inflammatory microenvironment. The effect of immune cells and inflammatory cytokines on the surface expression of programmed cell death-1 ligand 1 (PD-L1) and tumor immune evasion was investigated using flow cytometry (FCM) and an in vivo xenotransplantation model. Based on the data, PHA-activated, but not resting, immune cells were able to promote the surface expression of PD-L1 in Tca8113 oral squamous carcinoma cells via the secretion of inflammatory cytokines, but not by cell-cell contact. The majority of the inflammatory cytokines had no significant effect on the proliferation, cell cycle progression and apoptosis of the Tca8113 cells, although they each induced the expression of PD-L1 in a dose-dependent manner. In total, 99% of the Tca8113 cells expressed PD-L1 following treatment with the supernatant of PHA-stimulated PBMCs. The PHA-supernatant pretreated Tca8113 cells unusually induced Tca8113 antigen-specific CD8+ T cell apoptosis in vitro and the evasion of antigen-specific T cell attraction in a nude mouse tumor-bearing model. These results indicate a new mechanism for the promotion of tumor immune evasion by the tumor inflammatory microenvironment

High-resolution transmission electron microscope (HRTEM) study of the transformation interface and substructure in NiTiHf40 melt–spun ribbons

The fine structures of self-accommodation spear-like martensite variant groups and the interface between the martensite region and the amorphous phase region in NiTi-Hf-40 melt-spun ribbons were studied by using high-resolution transmission electron microscopy (HRTEM). In the self-accommodation lath plate martensite group, the variants prefer to form orthogonal morphology of spear-like martensite on both sides of melt-spun ribbons. Some variant pairs were of the (011)(B19). Type I twin related with straight and coherent interface while the interface between other variants is curved and incoherent. The main substructure in variants of the group was not the (001)(B19). compound twin but the (011)(B19). Type I microtwin and (011) stacking faults. The interface between the amorphous phase and the martensite region showed high energy and nonequilibrium configuration. Some area in the interface is straight but not smooth and exhibited an irregular configuration and some area in the interface has an obvious zigzag configuration. Energy-dispersive spectroscopy (EDX) analysis of the composition in NiTi-Hf-40 ribbon showed that the Ni and Ti content were different in the martensite region and in the amorphous phase. The amorphous phase and the martensite coexisted in NiTi-Hf ribbons when the cooling rate was high enough. The higher hardness and brittleness of Hf-40 compared to those of lower Hf content NiTi-Hf alloys were due to the not retained austenite, the very small variant pair and the coexisting amorphous phase

Macrophage activating factor: A potential biomarker of periodontal health status.

OBJECTIVE In periodontitis, activated macrophages not only initiate immune responses to periodontal-pathogen infections, but also damage the periodontal tissues by releasing a series of inflammatory cytokines. Macrophage-activating factor (MAF) and macrophage-chemotactic factor (MCF) are two important mediators involved in macrophage accumulation, activation and function. This study analyzed the levels of salivary MAF and MCF in healthy individuals and those with different periodontal diseases, and assessed the usefulness of salivary MAF and MCF as diagnostic biomarkers in periodontal tissue health status. DESIGN Ninety-five saliva specimens were collected from healthy individuals (n=19), and patients with gingivitis (n=19), mild periodontitis (n=17), moderate periodontitis (n=20), and severe periodontitis (n=20). Pocket probing depth (PPD) and alveolar bone loss (ABL) were recorded via periodontal probing and dental radiography, respectively. Salivary MAF and MCF concentrations were assayed using enzyme-linked immunosorbent assays. RESULTS MAF level tended to increase in saliva as periodontal diseases progressed (healthy periodontium<gingivitis<mild periodontitis<moderate periodontitis<severe periodontitis). The concentration of salivary MAF in periodontitis correlated positively with ABL (r=0.758) and PPD (r=0.779). In contrast, salivary MCF levels increased significantly only in periodontitis. CONCLUSIONS Salivary MAF levels correlate positively with tissue destruction in periodontal diseases. It is a potential valuable biomarker that could be used to assess periodontal health status.

High efficient anti-cancer drug delivery systems using tea polyphenols reduced and functionalized graphene oxide:

Targeted drug delivery is urgently needed for cancer therapy, and green synthesis is important for the biomedical use of drug delivery systems in the human body. In this work, we report two targeted delivery systems for anticancer drugs based on tea polyphenol functionalized and reduced graphene oxide (TPGs). The obtained TPGs demonstrated an efficient doxorubicin loading capacity as high as 3.430 × 106 mg g−1 and 3.932 × 104 mg g−1, and exhibited pH-triggered release. Furthermore, the kinetic models, adsorption isotherms, and possible loading mechanisms were investigated in details. Compared to TPG1 and free doxorubicin, TPG2 is biocompatible to normal cells even at high concentrations and promotes tumor cells death by delivering the doxorubicin mainly to the nuclei. These results were confirmed using cell viability tests and confocal laser microscopy. Moreover, apoptosis tests showed that the mechanism of cancer cell death induced by TPG1 and TPG2 might follow the similar mechanisms. Taken together, these results demonstrate that TPGs provide a multifunctional drug delivery system with a greater loading capacity and pH-sensitive drug release for enhanced cancer therapy. The high drug payload capability and enhanced antitumor efficacy demonstrate that we developed systems are promising for various biomedical applications and cancer therapy.

Expression of programmed death 1 ligand 1 on periodontal tissue cells as a possible protective feedback mechanism against periodontal tissue destruction

Programmed death 1 ligand 1 (PD-L1) is a negative co-stimulatory molecule in immune responses. Previous reports have indicated that inflammatory cytokines can upregulate the expression of PD-L1 in tumor cells, which in turn suppresses host immune responses. Periodontitis is characterized by persistent inflammation of the periodontium, which is initiated by infection with oral bacteria and results in damage to cells and the matrices of the periodontal connective tissues. In the present study, the expression and function of PD-L1 in periodontal tissue destruction were examined. Periodontal ligament cells (PDLCs) were stimulated by inflammatory cytokines and periodontal pathogens. The expression and function of PD-L1 on the surface of PDLCs was investigated using flow cytometry in vitro. Periodontal disease was induced by the injection of Porphyromonas gingivalis in mouse models. The expression levels of PD-L1 in the periodontal tissues of the mice were analyzed using flow cytometry and immunohistochemistry. PD-L1 was inducibly expressed on the PDLCs by the inflammatory cytokines and periodontal pathogens. The inflammation-induced expression of PD-L1 was shown to cause the apoptosis of activated T lymphocytes and improve the survival of PDLCs. Furthermore, in the mouse model of experimental periodontitis, the expression of PD-L1 in severe cases of periodontitis was significantly lower, compared with that in mild cases. By contrast, no significant differences were observed between the healthy control and severe periodontitis groups. The results of the present study showed that the expression of PD-L1 may inhibit the destruction of periodontal tissues, indicating the involvement of a possible protective feedback mechanism against periodontal infection.

Increased expression of high-mobility group nucleosomal-binding domain 2 protein in various tumor cell lines

High mobility group nucleosomal-binding domain 2 (HMGN2) is an abundant non-histone nuclear protein of vertebrates and invertebrates. The aim of the present study was to characterize the endogenous expression of HMGN2 in various types of tumor cell. Western blotting was performed to analyze HMGN2 expression in the following tumor cell lines: H1975, HSC-4, MDA-MB-468, MDA-MB-231, SCC-25 and THP-1. Periodontal ligament cells (PDLCs) were included as a noncancerous control. HMGN2 was detected in human oral squamous cell carcinoma tissues by immunohistochemical analysis. The results demonstrated that the expression of HMGN2 was increased in the majority of tumor cell lines, particularly MDA-MB-468 and THP-1 cells, compared with PDLCs. The expression of HMGN2 in oral squamous cell carcinoma tissue was significantly increased compared with the expression in normal tissue. Furthermore, the expression of HMGN2 in metastatic oral squamous cell carcinoma tissues was increased compared with that in its non-metastatic counterpart. These results indicated that HMGN2 may serve an important function in the growth and metastasis of tumor cells.