BackgroundmicroRNAs are small noncoding RNAs that modulate a variety of cellular processes by regulating multiple targets, which can promote or inhibit the development of malignant behaviors. Accumulating evidence suggests that miR-675-5p plays important roles in human carcinogenesis. However, its precise biological role remains largely elusive. This study examined the role of miR-675-5p in non- small cell lung cancer (NSCLC).MethodsThe expression of miR-675-5p was analyzed by real-time quantitative PCR (qRT-PCR). The effect of miR-675-5p on proliferation was evaluated through MTT and colony formation assays, and cell migration and invasion were evaluated through transwell assays. The expression of target proteins and downstream molecules was analyzed by western blotting and immunohistochemical staining. The luciferase reporter assay was used to assess the target genes of miR-675-5p in non-small cell lung cancer cells.ResultsThe expression levels of miR-675-5p in NSCLC tissues were significantly reduced compared to those in adjacent non-cancerous tissues (P < 0.001). The expression of miR-675-5p in patients with non-small cell lung cancer had a negative correlation with lymph node metastasis (P < 0.01) and TNM stage (P < 0.05). Down-regulation of miR-675-5p promoted cell growth, proliferation, colony formation, invasion and migration, and promoted the tumorigenicity graft growth of nude mice in vivo (P < 0.01); whereas up-regulation of miR-675-5p had the contrary effects. The luciferase reporter assay showed that GPR55 was a direct target gene of miR-675-5p. Overexpression of miR-675-5p can lead to the down-regulation of GPR55 and its signaling pathway, whereas the effect can be reversed by down-regulation of miR-675-5p expression.ConclusionsmiR-675-5p functions as a novel tumor suppressor in NSCLC and the anti-oncogenic activity may involve its inhibition of the target gene GPR55. These findings suggest the possibility for miR-675-5p as a therapeutic target in NSCLC.Electronic supplementary materialThe online version of this article (doi:10.1186/s12943-015-0342-0) contains supplementary material, which is available to authorized users.

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Recently H19 has been demonstrated to be up-regulated in esophageal squamous cell carcinoma (ESCC) and shown to be the precursor of miR-675 that encodes miR-675-5p conservatively. miR-675 is overexpressed in many human cancers; however, the function of miR-675-5p is largely unknown in ESCC. In this study, we found that miR-675-5p expression was significantly increased in ESCC tissues and cell lines and related with ESCC progression and poor prognosis. We also showed here that down-regulation of miR-675-5p in ESCC cells dramatically induced cell G1 arrest and reduced cell proliferation, colony formation, migration and invasion in vitro as well as tumorigenesis and tumor metastasis in vivo. We subsequently identified that REPS2 was a target gene of miR-675-5p. We found that inhibition of miR-675-5p up-regulated the expression of REPS2, inhibited RalBP1/RAC1/CDC42 signaling pathway. Inversely, interference of REPS2 abrogated the effect induced by miR-675-5p inhibition, which resembled the function of miR-675-5p up-regulation. Taken together, our findings suggested that miR-675-5p might play an oncogenic role in ESCC through RalBP1/RAC1/CDC42 signaling pathway by inhibiting REPS2 and might serve as a valuable prognostic biomarker and therapeutic target for ESCC patients.

Background/Aims: Primary angiosarcoma of the small intestine is a rare neoplasia, and there are limited data from systematic analyses. The aim of this study is to describe the clinical and pathological characteristics in addition to the prognostic factors for this rare neoplasia. Methods: We retrospectively collected the clinical records and prognostic information of 66 patients with small intestine angiosarcoma reported between 1970 and 2017. We used the Chi-square test, the log-rank test, and Cox regression analyses to evaluate the data. Results: There were 66 patients diagnosed with small intestine angiosarcoma. The onset age ranged from 24–92 years old. There were 24 patients diagnosed before the year 2000, and 42 patients were diagnosed after 2000. The data indicated that 49 cases were diagnosed as primary disease, and the remaining 15 cases were secondary disease. The main clinical symptoms were nonspecific and included gastrointestinal (GI) bleeding and abdominal pain. Additionally, we found multi-center foci were one of the characteristics of this disease. Radiation-induced small intestine angiosarcoma (RSIA) is a special type of disease with a similar prognosis. This type was more frequent in females and decreased after the year 2000. We also found that GI bleeding was less common in RSIA cases. The log-rank test results revealed that old-age, poor differentiation, and GI bleeding were associated with worse prognosis. Surgical treatment showed a trend toward a prolonged survival time. However, the result was not statistically significant. Our results show treatment with adjuvant therapy improved prognosis. The multivariate Cox analysis demonstrated adjuvant therapy was an independent indicator of a favorable outcome in small intestine angiosarcoma patients. Conclusion: Pay attention to the unexplained gastrointestinal bleeding could lead to a faster diagnosis and control of small intestine angiosarcoma. Furthermore, treatments including adjuvant therapy can effectively improve the prognosis.