Background Recurrence and metastasis are the leading causes of tumour-related death in patients with oesophageal squamous cell carcinoma (ESCC). Tumour-infiltrating natural killer cells (NK cells) display powerful cytotoxicity to tumour cells and play a pivotal role in tumour therapy. However, the phenotype and functional regulation of NK cells in oesophageal squamous cell carcinoma (ESCC) remains largely unknown. Methods Single cell suspensions from blood and tissue samples were isolated by physical dissociation and filtering through a 70 μm cell strainer. Flow cytometry was applied to profile the activity and function of NK cells, and an antibody chip experiment was used to identify and quantitate cytokine levels. We studied IL-6 and IL-8 function in primary oesophageal squamous carcinoma and NK cell co-cultures in vitro and by a xenograft tumour model in vivo. Western blotting was used to quantitate STAT3 (signal transducer and activator of transcription 3) and p-STAT3 levels. Finally, we performed an IHC array to analyse IL-6/IL-8 (interleukin 6/interleukin 8) expression in 103 pairs of tumours and matched adjacent tissues of patients with ESCC to elucidate the correlation between IL-6 or IL-8 and clinical characteristics. Results The percentages of NK cells in both peripheral blood and tumour tissues from patients with ESCC were significantly increased in comparison with those in the controls and correlated with the clinical characteristics. Furthermore, the decrease in activating receptors and increase in inhibitory receptors on the surface of tumour-infiltrating NK cells was confirmed by flow cytometry. The level of granzyme B, the effector molecule of tumour-infiltrating NK cells, was also decreased. Mechanistically, primary ESCC cells activated the STAT3 signalling pathway on NK cells through IL-6 and IL-8 secretion, leading to the downregulation of activating receptors (NKp30 and NKG2D) on the surface of NK cells. An ex vivo study showed that blockade of STAT3 attenuated the IL-6/IL-8-mediated impairment of NK cell function. Moreover, the expression of IL-6 or IL-8 in tumour tissues was validated by immunohistochemistry to be positively correlated with tumour progression and poor survival, respectively. Conclusions Tumour cell-secreted IL-6 and IL-8 impair the activity and function of NK cells via STAT3 signalling and contribute to oesophageal squamous cell carcinoma malignancy. Electronic supplementary material The online version of this article (10.1186/s13046-019-1310-0) contains supplementary material, which is available to authorized users.

Mammalian cells have been widely used to produce therapeutic proteins in stirred bioreactors in suspension culture. Local hydrodynamics can have a great impact on cell proliferation and protein synthesis, but there are few reports on spatial heterogeneity of nutrients, gas bubbles, and mass transfer coefficients. We have employed computational fluid dynamics (CFD) coupled with population balance equations to study local hydrodynamics in a 20 L stirred bioreactor. The flow patterns, energy dissipation rates, gas volume fraction, gas bubble size distribution and local mass transfer coefficient have been displayed throughout the whole bioreactor. Their implications for mammalian cell culture have been discussed. This study provides an insight into rational design and optimum operation conditions in a stirred bioreactor for mammalian cell cultivation.

Background To reveal detailed histopathological changes, virus distributions, immunologic properties and multi‐omic features caused by SARS‐CoV‐2 in the explanted lungs from the world's first successful lung transplantation of a COVID‐19 patient. Materials and methods A total of 36 samples were collected from the lungs. Histopathological features and virus distribution were observed by optical microscope and transmission electron microscope (TEM). Immune cells were detected by flow cytometry and immunohistochemistry. Transcriptome and proteome approaches were used to investigate main biological processes involved in COVID‐19‐associated pulmonary fibrosis. Results The histopathological changes of the lung tissues were characterized by extensive pulmonary interstitial fibrosis and haemorrhage. Viral particles were observed in the cytoplasm of macrophages. CD3+CD4− T cells, neutrophils, NK cells, γ/δ T cells and monocytes, but not B cells, were abundant in the lungs. Higher levels of proinflammatory cytokines iNOS, IL‐1β and IL‐6 were in the area of mild fibrosis. Multi‐omics analyses revealed a total of 126 out of 20,356 significant different transcription and 114 out of 8,493 protein expression in lung samples with mild and severe fibrosis, most of which were related to fibrosis and inflammation. Conclusions Our results provide novel insight that the significant neutrophil/ CD3+CD4− T cell/ macrophage activation leads to cytokine storm and severe fibrosis in the lungs of COVID‐19 patient and may contribute to a better understanding of COVID‐19 pathogenesis.

Background:No analytic epidemiological study has examined the relationship between use of muscle-building supplements (MBSs) and testicular germ cell cancer (TGCC) risk.Methods:We conducted a population-based case–control study including 356 TGCC cases and 513 controls from Connecticut and Massachusetts.Results:The odds ratio (OR) for ever use of MBSs in relation to risk of TGCC was significantly elevated (OR=1.65, 95% confidence interval (CI): 1.11–2.46). The associations were significantly stronger among early users, men with more types of MBSs used, and longer periods of use.Conclusions:MBS use is a potentially modifiable risk factor that may be associated with TGCC.

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