Ginsenoside Rh2 enhances immune surveillance of natural killer (NK) cells via inhibition of ERp5 in breast cancer.

BACKGROUND: One critical component of the immune system that prevents breast cancer cells from forming distant metastasis is natural killer (NK) cells participating in immune responses to tumors. Ginsenoside Rh2 (GRh2) as one of the major active ingredients of ginseng has been employed in treatment of cancers, but the function of GRh2 in modulating the development of breast cancer remains elusive. PURPOSE: This study was to dissect the effect of GRh2 against breast cancer and its potential mechanisms associated with NK cells, both in vitro and in vivo. METHODS: MDA-MB-231 and 4T1 cells were used to establish in situ and hematogenous mouse models. MDA-MB-231 and MCF-7 were respectively co-cultured with NK92MI cells or primary NK cells in vitro. Anti-tumor efficacy of GRh2 was verified by immunohistochemistry (IHC), Cell Counting Kit-8 (CCK8), high resolution micro-computed tomography (micro-CT) scanning of lungs and hematoxylin and eosin (H&E) staining. Lactate dehydrogenase (LDH) cytotoxicity assay, flow cytometry, in vivo depletion of NK cells, enzyme-linked immunosorbent assay (ELISA), western blot, quantitative reverse transcription polymerase chain reaction (qRT-PCR), immunofluorescence and cell transfection were performed for investigating the anti-tumor mechanisms of GRh2. Molecular docking, microscale thermophoresis (MST) and cellular thermal shift assay (CETSA) were employed to determine the binding between endoplasmic reticulum protein 5 (ERp5) and GRh2. RESULTS: We demonstrated that GRh2 exerted prominent impacts on retarding the growth and metastasis of breast cancer through boosting the cytotoxic function of NK cells, as validated by the elevated release of perforin, granzyme B and interferon-γ (IFN-γ). Mechanistical studies revealed that GRh2 was capable of diminishing the expression of ERp5 and GRh2 directly bound to ERp5 in MDA-MB-231 cells as well as on a recombinant protein level. GRh2 prevented the formation of soluble MICA (sMICA) and upregulated the expression level of MICA in vivo and in vitro. Importantly, the reduced lung metastasis of breast cancer by GRh2 was almost abolished upon the depletion of NK cells. Moreover, GRh2 was able to insert into the binding pocket of ERp5 directly. CONCLUSION: We firstly demonstrated that GRh2 played a pivotal role in augmenting NK cell activity by virtue of modulating the NKG2D-MICA signaling axis via directly binding to ERp5, and may be further optimized to a therapeutic agent for the treatment of breast cancer.

Mindfulness and burnout among bedside registered nurses: A cross-sectional study.

Nursing is a high stress job, and burnout of nurses is of particular concern. The aim of this cross-sectional survey study was to examine the relationship between mindfulness and burnout, and how the mindfulness facets vary in their associations with the different domains of burnout for Chinese nurses. A sample of registered bedside nurses working in a tertiary Chinese hospital (n = 763) was surveyed from February to June 2017 regarding mindfulness (i.e. acting with awareness, describing, and non-judging of experiences), burnout (i.e. emotional exhaustion, depersonalization, and personal accomplishment), and sociodemographic and job-related characteristics. Higher scores on the three facets of mindfulness were associated with less emotional exhaustion and depersonalization, and acting with awareness showed the highest regression coefficients. Personal accomplishment was positively associated with acting with awareness and describing, whereas it was negatively related to non-judging of experiences. Describing was the strongest facet associated with personal accomplishment. In conclusion, there were clearly correlations between mindfulness as a personal trait and burnout among Chinese bedside nurses. These findings suggest the potential benefits of tailored mindfulness-based interventions in reducing nurse burnout in China.