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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.

Purpose of review An increasing number of patients are turning to cannabis and cannabinoids for management of their palliative and nonpalliative cancer pain and other cancer-related symptoms. Canadians have a legal framework for access to medical cannabis, which provides a unique perspective in a setting lacking robust clinical evidence. This review seeks to delineate the role of cannabis and cannabinoids in cancer pain management and offers insight into the Canadian practice. Recent findings A cohort study using nabiximols on advanced cancer pain in patients already optimized on opioids, over 3 weeks, demonstrated improved average pain score. A large observational study of cancer patients using cannabis over 6 months demonstrated a decreased number of patients with severe pain and decreased opioid use, whereas the number of patients reporting good quality of life increased. Summary Good preclinical animal data and a large body of observational evidence point to the potential efficacy of cannabinoids for cancer pain management. However, there are relatively weak data pointing to clinical efficacy from clinical trial data to date. In Canada, the burgeoning cannabis industry has driven the population to embrace a medicine before clinical evidence. There remains a need for high-quality randomized controlled trials to properly assess the effectiveness and safety of medical cannabis, compared with placebo and standard treatments for cancer-related symptoms.

Cartilage has a limited self-repair capability and the repair of large cartilage defects remains a challenge in clinic. This study aimed to investigate the effect of mesenchymal stem cells (MSCs) loaded three-dimensional bilayer collagen scaffold for cartilage repair. Cross-linked three-dimensional bilayer collagen scaffolds seeded with or without MSCs were implanted into large cartilage defects (4 mm in diameter; 3 mm in depth) in rabbit knees. The untreated cartilage defects served as control. The tissue response was evaluated at 6 and 12 weeks after implantation by general histology and semi-quantitative histological grading systems. In addition, the repaired tissues were evaluated by mechanical test at 12 weeks after implantation. The MSCs-loaded collagen scaffold group showed the most hyaline cartilage, highest histological scores and compressive modulus. Moreover, it showed a good integration with the subchondral bone and adjacent cartilage. The structure of the novel bilayer collagen scaffolds provided architectural support for the differentiation of MSCs and demonstrated successful induction of in vivo chondrogenesis. These findings suggested that MSCs-loaded bilayer collagen scaffold could be an appealing candidate to be used for cartilage regeneration.

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