Several studies have shown that tRNAs can be enzymatically cleaved to generate distinct classes of tRNA-derived fragments (tRF). Here, we report that tRF/miR-1280, a 17-bp fragment derived from tRNA and pre-miRNA, influences Notch signaling pathways that support the function of cancer stem-like cells (CSC) in colorectal cancer progression. tRF/miR-1280 expression was decreased in human specimens of colorectal cancer. Ectopic expression of tRF/miR-1280 reduced cell proliferation and colony formation, whereas its suppression reversed these effects. Mechanistic investigations implicated the Notch ligand JAG2 as a direct target of tRF/miR-1280 binding through which it reduced tumor formation and metastasis. Notably, tRF/miR-1280-mediated inactivation of Notch signaling suppressed CSC phenotypes, including by direct transcriptional repression of the Gata1/3 and miR-200b genes. These results were consistent with findings of decreased levels of miR-200b and elevated levels of JAG2, Gata1, Gata3, Zeb1, and Suz12 in colorectal cancer tissue specimens. Taken together, our results established that tRF/miR-1280 suppresses colorectal cancer growth and metastasis by repressing Notch signaling pathways that support CSC phenotypes. Furthermore, they provide evidence that functionally active miRNA can be derived from tRNA, offering potential biomarker and therapeutic uses. .

BackgroundOrthotopic liver transplantation is the only effective treatment for liver failure but limited with shortage of available donor organs. Recent studies show promising results of mesenchymal stem cells (MSCs)-based therapies.MethodsWe systematically investigate the therapeutic effects of MSCs or MSC-conditioned medium (MSC-CM) in ameliorating fulminant hepatic failure (FHF) and chronic liver fibrosis in mice. In addition, extensive flow cytometry analysis of spleens from vehicle and MSC- and MSC-CM-treated mice was applied to reveal the alteration of inflammatory state.ResultsIn FHF model, MSCs treatment reduced remarkably the death incidents; the analysis of gross histopathology showed that control livers were soft and shrunken with extensive extravasated blood, which was gradually reduced at later time points, while MSC–treated livers showed gross pathological changes, even 24 h after MSC infusion, and hematoxylin and eosin staining revealed dramatical hepatocellular death with cytoplasmic vacuolization suppressed by MSCs treatment; flow cytometry analysis of total lymphocytes showed that macrophages (F4/80) infiltrated into control livers more than MSC-treated livers; by contrast, MSC-CM partially ameliorates FHF. In chronic liver injury model, MSC and MSC-CM both suppressed fibrogenesis and necroinflammatory, and the later was better; activation of hepatic stellate cells (α-SMA) was inhibited; glycogen synthesis and storage (indicated by periodic acid-Schiff -staining) was improved; liver regeneration (Ki67) was promoted while liver apoptosis (TUNEL) was reduced. In the in vitro, MSCs promote macrophage line RAW264.7 apoptosis and MSC-CM promotes apoptosis and inhibits proliferation of HSC line LX-2. We also found that MSCs and MSC-CM could improve spleen; MSC-CM increased levels of Th2 and Treg cells, and reduced levels of Th17 cells, whereas levels of Th1 cells were unchanged; comparatively, MSC treatment did not affect Th17 and Treg cells and only slightly alters inflammatory state; MSC and MSC-CM treatment both substantially down-regulated macrophages in the spleens.ConclusionBoth MSCs and MSC-CM exert therapeutic effects by acting on various key cells during the pathogenesis of FHF and chronic fibrosis, stimulating hepatocyte proliferation and suppressing apoptosis, down-regulating infiltrating macrophages, converting CD4+ T lymphocyte system into an anti-inflammatory state, and facilitating hepatic stellate cell death.Electronic supplementary materialThe online version of this article (doi:10.1186/s12967-016-0792-1) contains supplementary material, which is available to authorized users.

Adiponectin is an adipocyte-secreted adipokine with pleiotropic actions. Clinical evidence has shown that serum adiponectin levels are increased and that adiponectin can protect pancreatic beta cells against apoptosis, which suggests that adiponectin may play an anti-apoptotic role in pancreatic cancer (PC). Here, we investigated the effects of adiponectin on PC development and elucidated the underlying molecular mechanisms. Adiponectin deficiency markedly attenuated pancreatic tumorigenesis in vivo. We found that adiponectin significantly inhibited the apoptosis of both human and mouse pancreatic cancer cells via adipoR1, but not adipoR2. Furthermore, adiponectin can increase AMP-activated protein kinase (AMPK) phosphorylation and NAD-dependent deacetylase sirtuin-1 (Sirt1) of PC cells. Knockdown of AMPK or Sirt1 can increase the apoptosis in PC cells. AMPK up-regulated Sirt1, and Sirt1 can inversely phosphorylate AMPK. Further studies have shown that Sirt1 can deacetylate peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC1α), which can increase the expression levels of mitochondrial genes. Thus, adiponectin exerts potent anti-apoptotic effects on PC cells via the activation of AMPK/Sirt1/PGC1α signaling. Finally, adiponectin can elevate β-catenin levels. Taken together, these novel findings reveal an unconventional role of adiponectin in promoting pancreatic cancers, and suggest that the effects of adiponectin on tumorigenesis are highly tissue-dependent.

Adiponectin is an adipocyte-derived circulating protein with beneficial effects on injured livers. Adiponectin-deficient (adipo(−/−)) mice develop enhanced liver fibrosis, suggesting that adiponectin could be a therapeutic target for liver injury. In the present study, we investigated the protective role of ADP355, an adiponectin-based active short peptide, in thioacetamide (TAA)-induced acute injury and chronic liver fibrosis in mice. ADP355 remarkably reduced TAA-induced necroinflammation and liver fibrosis. ADP355 treatment increased liver glycogen, decreased serum alanine transaminase and alkaline phosphatase activity, and promoted body weight gain, hyper-proliferation and hypo-apoptosis. In addition, ADP355 administration suppressed the TAA-induced activation of hepatic stellate cells and macrophages in the liver. These were associated with the inactivation of TGF-β1/SMAD2 signaling and the promotion of AMPK and STAT3 signaling. Sensitivity of adipo(−/−) mice to chronic liver injury was decreased with ADP355. In conclusion, ADP355 could mimic adiponectin’s action and may be suitable for the preclinical or clinical therapy of chronic liver injury.

Plumbagin is a quinonoid constituent extracted from Plumbago genus, and it exhibits diverse pharmacological effects. This study thoroughly investigated the effects of plumbagin on thioacetamide-induced acute and chronic liver injury. Results shown that plumbagin increased survival rate, reduced liver congestion and inflammation, and decreased macrophages and neutrophils in the fulminant hepatic failure model, and remarkably diminished liver fibrosis and inflammation in the chronic liver injury model. Furthermore, plumbagin significantly suppress the HSCs/myofibroblasts activation by reduced expression of markers α-SMA and COL-1/3, and reduced macrophage in liver. In the in vitro study, plumbagin induced apoptosis and suppressed the proliferation of LX-2 cells (human HSCs). Plumbagin treatment increased AMPK phosphorylation and attenuated NF-κB, STAT3, and Akt/mTOR signals in LX-2 cells, while SMAD2 phosphorylation was not changed. Noticeably, plumbagin promoted AMPK binding to p300 which is a cofactor of SMAD complex, this may further competitively decreases the p300/SMAD complex initiated transcription of COL-1/3 and α-SMA. Additionally, plumbagin hampered inflammation related NF-κB signal in RAW 264.7 cells. In conclusion, these findings indicate that plumbagin may be a powerful drug candidate to protect the liver from acute and chronic damage by inhibiting inflammation and collagen production.