Cancer cell-derived exosomal miR-425-3p induces white adipocyte atrophy.

White adipose tissue wasting plays a critical role in the development and progression of cancer cachexia. However, the mechanism behind the loss of adipose tissue remains ill-defined. In this study, we found that cancer cell-derived exosomes highly expressed miR-425-3p. Administration of cancer cell-derived exosomes significantly inhibited proliferation and differentiation of human preadipocytes-viscereal (HPA-v) cells. In mature adipocytes, cancer cell-derived exosomes activated cAMP/PKA signalling and lipophagy, leading to adipocyte lipolysis and browning of white adipocytes. These exosomes-induced alterations were almost abolished by endocytosis inhibitor cytochalasin D (CytoD) and antagomiR-425-3p, or reproduced by miR-425-3p mimics. In addition, bioinformatics analysis and luciferase reporter assay revealed that miR-425-3p directly targeted proliferation-related genes such as GATA2, IGFBP4, MMP15, differentiation-related gene CEBPA, and phosphodiesterase 4B gene (PDE4B). Depletion of PDE4B enhanced cAMP/PKA signalling and lipophagy, but had no effects on HPA-v proliferation and differentiation. Taken together, these results suggested that cancer cell-derived exosomal miR-425-3p inhibited preadipocyte proliferation and differentiation, increased adipocyte lipolysis, and promoted browning of white adipocytes, all of which might contribute to adipocyte atrophy and ultimately the loss of adipose tissue in cancer cachexia.Abbreviations: ADPN: adiponectin; aP2: adipocyte protein 2 or fatty acid binding protein 4 (FABP4); BCA: bicinchoninic acid assay; BFA: bafilomycin A1; BMI: body mass index; C/EBP: CCAAT/enhancer binding protein; CEBPA: CCAAT/enhancer-binding protein-alpha; C-Exo: cancer cell-derived exosomes; CNTL: control; CREB: cAMP-response element binding protein; CytoD: cytochalasin D; ECL: chemiluminescence; GATA2: GATA Binding Protein 2; HFD: high fat diet; HSL: hormone-sensitive lipase; IGFBP4: insulin like growth factor binding protein 4; IRS-1: insulin receptor substrate-1; ISO: isoproterenol hydrochloride; KD: knockdown; KO: knock out; LC3: microtubule-associated protein 1A/1B-light chain 3; LMF: lipid mobilizing factor; LPL: lipoprotein lipase; MMP15: matrix metallopeptidase 15; Mir-Inh-C-Exo: cancer cell-derived exosomes with miR-425-3p inhibition; mTOR: mammalian target of rapamycin; Mut: mutant; N-Exo: normal cell-derived exosomes; NSCLC: non-small cell lung cancer; PBS, phosphate buffered saline; PGC-1: peroxisome proliferator-activated receptor-gamma coactivator-1; PDEs: phosphodiesterases; PKI: PKA inhibitor; PKA: cAMP-dependent protein kinase; PLIN1: Perilipin 1; PTHRP: parathyroid hormone-related protein; PVDF: polyvinylidene difluoride; shRNA: short hairpin RNA; UCP1: uncoupling protein 1; WT: wild type.

MiRNA-20b/SUFU/Wnt axis accelerates gastric cancer cell proliferation, migration and EMT.

Previous research has found that miRNA-20b is highly expressed in gastric cancer (GC), however, its function and underlying mechanism are not clear. Wnt signaling pathway, implicated in tumorigeneisis, is activated in more than 30% of GC. We would like to characterize the biological behavior of miRNA-20b in terms of modulating Wnt/ß-catenin signaling and EMT. We showed that miRNA-20b inhibitors suppressed Topflash/Fopflash dependent luciferase activity and the ß-catenin nuclear translocation, resulting in inhibition of Wnt pathway activity and EMT. SUFU, negatively regulating Wnt and Hedgehog signaling pathway, was proved to be targeted by miRNA-20b. Moreover, additional knockdown of SUFU alleviated the inhibitory effect on Wnt pathway activity, EMT, cell proliferation/migration and colony formation caused by miRNA-20b inhibition. In summary, miRNA-20b is an oncogenic miRNA and promoted cell proliferation, migration and EMT in GC partially by activating Wnt pathway via targeting SUFU.

LncRNA NEAT1/miR-185-5p/IGF2 axis regulates the invasion and migration of colon cancer.

BACKGROUND: Long noncoding RNAs (lncRNA) are important in the growth and metastasis of colon cancer. The objective of this study was to describe the potential role of lncRNA NEAT1 in the progression of colon cancer. METHODS: Quantitative real-time polymerase chain reaction was used for detecting NEAT1, miR-185-5p, and IGF2 in colon cancer cells and tissues. The potential diagnostic value of NEAT1 in colon cancer was analyzed with the receiver operating characteristic curve. Kaplan-Meier method was applied for evaluating the association between NEAT1 expression and the overall survival of osteosarcoma patients, whereas Transwell assay was introduced to examine the potential invasion and migration of colon cancer cells. In addition, the binding of NEAT1/IGF2 to miR-185-5p was confirmed by RNA pull-down and RNA-binding protein immunoprecipitation assays and dual-luciferase reporter gene assay. Finally, rescue experiments were conducted to confirm the role of NEAT1/miR-185-5p/IGF2 axis in colon cancer. RESULTS: Colon cancer patients with low NEAT1 expression presented with longer overall survival than those with high expression. The migration and invasion of colon cancer cells were considerably promoted by overexpressed NEAT1. Both NEAT1 and IGF2 bound to miR-185-5p. CONCLUSION: NEAT1 upregulate IGF2 expression through absorbing miR-185-5p to enhances the migration and invasion of colon cancer cells.

Long non-coding RNA MDC1-AS inhibits human gastric cancer cell proliferation and metastasis through an MDC1-dependent mechanism.

Gastric cancer is the third leading cause of cancer-associated mortality worldwide and is one of the most common malignancies in China. However, the molecular mechanisms underlying the tumorigenesis of gastric cancer remain largely unclear. Long non-coding (Lnc)RNAs have been demonstrated to serve significant roles in the tumorigenesis of various types of cancer. The present study aimed to explore the role of the LncRNA mediator of DNA damage checkpoint protein 1-antisense RNA (MDC1-AS), the antisense transcript of MDC1, in human gastric cancer. The results revealed that the expression of MDC1-AS in human gastric cancer was significantly suppressed in vivo and in vitro. In addition, overexpression of MDC1-AS in the poorly differentiated gastric cancer cell line MKN28 significantly inhibited cell proliferation and metastasis, while the knockdown of MDC1-AS in well-differentiated MKN45 gastric cancer cells significantly increased proliferation and metastasis. The knockdown of MDC1 relieved the inhibitory effect of MDC1-AS on MKN28 cell proliferation and metastasis, while the overexpression of MDC1 attenuated the stimulatory effect of MDC1-AS knockdown in MKN45 cells. Thus, the present study demonstrated that MDC1-AS had an inhibitory on gastric tumorigenesis through an MDC1-dependent mechanism. This indicates that MDC1-AS is a potential novel therapeutic target for the diagnosis and treatment of human gastric cancer in the clinic.