Background Crohn's disease (CD) and ulcerative colitis (UC) result from pathophysiologically distinct dysregulated immune responses, as evidenced by the preponderance of differing immune cell mediators and circulating cytokine expression profiles. MicroRNAs (miRNAs) are small, noncoding RNAs that act as negative regulators of gene expression and have an increasingly recognized role in immune regulation. We hypothesized that differences in circulating immune cells in CD and UC patients are reflected by altered miRNA expression and that miRNA expression patterns can distinguish CD and UC from normal healthy individuals. Methods Peripheral blood was obtained from patients with active CD, inactive CD, active UC, inactive UC and normal healthy adults. Total RNA was isolated and miRNA expression assessed using miRNA microarray and validated by mature miRNA quantitative RT-PCR. Results Five miRNAs were significantly increased and two miRNAs (149* and miRplus-F1065) were significantly decreased in the blood of active CD patients as compared to healthy controls. Twelve miRNAs were significantly increased and miRNA-505* was significantly decreased in the blood of active UC patients as compared to healthy controls. Ten miRNAs were significantly increased and one miRNA was significantly decreased in the blood of active UC patients as compared to active CD patients. Conclusions Peripheral blood miRNAs can be used to distinguish active CD and UC from healthy controls. The data support the evidence that CD and UC are associated with different circulating immune cells types and that the differential expression of peripheral blood miRNAs may form the basis of future diagnostic tests for IBD.

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Through degrading bulk cytoplasmic materials into intermediate building blocks, autophagy refuels metabolism and maintains homeostasis under starvation and stress conditions. The context-dependent role of autophagy in cancer cells during tumorigenesis and tumor progression has been explored over the past decade; however, studies of autophagy in relation to the tumor microenvironment are still lacking. In this study, we investigated the role of autophagy in the cancer-associated fibroblasts (CAFs), a major component of the microenvironment that is important for the growth and development of cutaneous melanoma. Analysis of clinical biopsies revealed high levels of autophagy in fibroblasts that surrounded melanoma cells, but not in the non-tumor adjacent area. Fibroblasts co-cultured with any of multiple melanoma cell lines, but not melanocytes, also showed increased autophagic flux, which requires transforming growth factor beta (TGF-β) signaling. Knocking down autophagy-related (ATG) genes ATG5 or ATG7 in fibroblasts did not impair their proliferation in vitro, but inhibited the growth of co-engrafted melanoma cells in vivo. Further, by introducing intradermal melanoma allografts into mice that harbored fibroblast-specific Atg7 deletion, we observed remarkable tumor growth retardation. In order to mimic anti-autophagy therapy for patients, we generated mice that allowed conditional Atg7 depletion in their entire bodies, and found significant tumor growth suppression. Atg7 knockout mice contained elevated plasma levels of immune cell attractants, including CXCL9, CXCL10 and MCP-1. By inhibiting these cytokines/chemokines with atorvastatin, tumor growth in Atg7 knockout mice was completely rescued; while, there was no effect of atorvastatin on control mice. Taken together, our data show that through modulating the tumor microenvironment, stromal autophagy plays an important role during melanoma growth and development. Our findings indicate that stromal autophagy may represent a valuable therapeutic target that might induce less side effects and systemic toxicity. Citation Format: Ran Ellen Zhang, Natalie J. Guo, Nithya Krishnan, David Jelinek, Gizem Karsli Uzunbas, Xiaoqi Xie, Arek Gertych, Janice M. Mehnert, Beatrice Knudsen, Eileen White, Hilary A. Coller. Stromal autophagy is required for the growth of cutaneous melanoma. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4081.

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