Dysregulation of the gut microbiota/gut hormone axis contributes to the pathogenesis of irritable bowel syndrome (IBS). Melatonin plays a beneficial role in gut motility and immunity. However, altered expression of local mucosal melatonin in IBS and its relationship with the gut microbiota remain unclear. Therefore, we aimed to detect the colonic melatonin levels and microbiota profiles in patients with diarrhea-predominant IBS (IBS-D) and explore their relationship in germ-free (GF) rats and BON-1 cells. Thirty-two IBS-D patients and twenty-eight healthy controls (HCs) were recruited. Fecal specimens from IBS-D patients and HCs were separately transplanted into GF rats by gavage. The levels of colon mucosal melatonin were assessed by immunohistochemical methods, and fecal microbiota communities were analyzed using 16S rDNA sequencing. The effect of butyrate on melatonin synthesis in BON-1 cells was evaluated by ELISA. Melatonin levels were significantly increased and negatively correlated with visceral hypersensitivity in IBS-D patients. GF rats inoculated with fecal microbiota from IBS-D patients had high colonic melatonin levels. Butyrate-producing Clostridium cluster XIVa species, such as Roseburia species and Lachnospira species, were positively related to colonic mucosal melatonin expression. Butyrate significantly increased melatonin secretion in BON-1 cells. Increased melatonin expression may be an adaptive protective mechanism in the development of IBS-D. Moreover, some Clostridium cluster XIVa species could increase melatonin expression via butyrate production. Modulation of the gut hormone/gut microbiota axis offers a promising target of interest for IBS in the future.

The screening of non-small cell lung cancer (NSCLC) tumors for anaplastic lymphoma receptor tyrosine kinase (ALK) gene rearrangements is important because of the dramatically favorable therapy response to ALK inhibitor. However, the exact mechanism of poor survival in ALK fusion lung cancer patients without receiving targeted therapy is unclear. In this study, total of 521 tumor specimens from Chinese patients with lung cancer were screened for ALK fusion by immunohistochemistry (IHC) and confirmed by fluorescence in situ hybridization (FISH). As results, there were no cases of coexisting EGFR and ALK mutations identified. Fourteen cases (2.7%) harbored ALK fusion, including eight solid adenocarcinomas with signet ring cell features, four acinar adenocarcinomas with cribriform pattern containing mucin, one adenosquamous carcinoma and one micropapillary adenocarcinoma with mucin. Six (42.9%) of fourteen patients with ALK-positive lung cancer had stage IV disease, and five ALK-positive patients treated with platinum-based chemotherapy had poor outcome (all patients were dead and the mean survival time was 12 months), compared to 72 months for patients with ALK inhibitor therapy. Furthermore, Five ALK-positive cases were analyzed by whole exome sequencing (WES) and via direct transcript counting using a digital probe-base (NanoString) to explore the driver genes. Deregulation of PI3K/AKT signaling pathway in ALK-positive lung cancer was demonstrated by WES analysis, and significantly increased mRNA of ALK, ROS1, MET, SPP1 and PI3K signaling pathway was identified by NanoString assay. The concordance between NanoString, IHC and FISH methodologies for detecting ALK fusion was 100%. Significant overexpression of SPP1 protein in ALK-positive lung cancer was confirmed by IHC compared to paired adjacent normal tissues and ALK-negative cancers. Thus we concluded that SPP1 overexpression is associated with poor outcomes for patients with ALK fusion lung cancer without receiving targeted therapy and PI3K/AKT/SPP1 pathway may become the promising targets in patients with aggressive lung cancer.