BackgroundNon-coding RNAs (ncRNAs) have been shown to regulate gene expression involved in tumor progression of multiple malignancies. Our previous studies indicated that large tumor suppressor kinase 1 (LATS1), a core part of Hippo signaling pathway, functions as a tumor suppressor in gastric cancer (GC). But, the underlying molecular mechanisms by which ncRNAs modulate LATS1 expression in GC remain undetermined.MethodsThe correlation of LATS1 and has-miR-424-5p (miR-424) expression with clinicopathological characteristics and prognosis of GC patients was analyzed by TCGA RNA-sequencing data. A novel circular RNA_LARP4 (circLARP4) was identified to sponge miR-424 by circRNA expression profile and bioinformatic analysis. The binding site between miR-424 and LATS1 or circLARP4 was verified using dual luciferase assay and RNA immunoprecipitation (RIP) assay. The expression and localization of circLARP4 in GC tissues were investigated by fluorescence in situ hybridization (FISH). MTT, colony formation, Transwell and EdU assays were performed to assess the effects of miR-424 or circLARP4 on cell proliferation and invasion.ResultsIncreased miR-424 expression or decreased LATS1 expression was associated with pathological stage and unfavorable prognosis of GC patients. Ectopic expression of miR-424 promoted proliferation and invasion of GC cells by targeting LATS1 gene. Furthermore, circLARP4 was mainly localized in the cytoplasm and inhibited biological behaviors of GC cells by sponging miR-424. The expression of circLARP4 was downregulated in GC tissues and represented an independent prognostic factor for overall survival of GC patients.ConclusioncircLARP4 may act as a novel tumor suppressive factor and a potential biomarker in GC.Electronic supplementary materialThe online version of this article (10.1186/s12943-017-0719-3) contains supplementary material, which is available to authorized users.

BackgroundCircular RNAs (circRNAs) are a new type of non-coding RNAs and their functions in gastric cancer (GC) remain unclear. Recent studies have revealed that circRNAs play an important role in cancer development and certain types of pathological responses, acting as microRNA (miRNA) sponges to regulate gene expression.MethodsCircNet was used to screen potential circRNAs and validated circYAP1 expression levels in 17 GC tissues by quantitative real-time PCR (qRT-PCR) and another 80 paired GC tissues by FISH. CircYAP1 overexpression and knockdown experiments were conducted to assess the effects of circYAP1 in vitro and in vivo, and its molecular mechanism was demonstrated by RNA in vivo precipitation assays, western blotting, luciferase assay and rescue experiments.ResultsCircYAP1 expression level was significantly lower in GC tissues than the adjacent normal tissues, and GC patients with circYAP1 low expression had shorter survival times as compared with those with circYAP1 high expression. Functionally, circYAP1 overexpression inhibited cell growth and invasion in vitro and in vivo, but its knockdown reversed these effects. Further analysis showed that circYAP1 sponged miR-367-5p to inhibit p27 Kip1 expression and GC progression.ConclusionOur findings demonstrate that circYAP1 functions as a tumor suppressor in GC cells by targeting the miR-367-5p/p27 Kip1 axis and may provide a prognostic indicator of survival in GC patients.Electronic supplementary materialThe online version of this article (10.1186/s12943-018-0902-1) contains supplementary material, which is available to authorized users.

Chemo-PTT, which combines chemotherapy with photothermal therapy, offers a viable approach for the complete tumor eradication but would likely fail in drug-resistant situations if conventional chemotherapeutic agents are used. Here we show that a type of copper (Cu)-palladium (Pd) alloy tetrapod nanoparticles (TNP-1) presents an ideal solution to the chemo-PTT challenges. TNP-1 exhibit superior near-infrared photothermal conversion efficiency, thanks to their special sharp-tip structure, and induce pro-survival autophagy in a shape- and composition-dependent manner. Inhibition of autophagy with 3-methyl adenine or chloroquine has a remarkable synergistic effect on TNP-1-mediated PTT in triple-negative (4T1), drug-resistant (MCF7/MDR) and patient-derived breast cancer models, achieving a level of efficacy unattainable with TNP-2, the identically-shaped CuPd nanoparticles that have a higher photothermal conversion efficiency but no autophagy-inducing activity. Our results provide a proof-of-concept for a chemo-PTT strategy, which utilizes autophagy inhibitors instead of traditional chemotherapeutic agents and is particularly useful for eradicating drug-resistant cancer.

KLF4 (Krüppel-like factor 4) has been implicated in vascular smooth muscle cell (VSMC) differentiation induced by transforming growth factor ␤ (TGF-␤). However, the role of KLF4 and mechanism of KLF4 actions in regulating TGF-␤ signaling in VSMCs remain unclear. In this study, we showed that TGF-␤1 inhibited cell cycle progression and induced differentiation in cultured rat VSMCs. This activity of TGF-␤1 was accompanied by up-regulation of KLF4, with concomitant increase in T␤RI (TGF-␤ type I receptor) expression. KLF4 was found to transduce TGF-␤1 signals via phosphorylation-mediated activation of Smad2, Smad3, and p38 MAPK. The activation of both pathways, in turn, increased the phosphorylation of KLF4, which enabled the formation of KLF4-Smad2 complex in response to TGF-␤1. Chromatin immunoprecipitation studies and oligonucleotide pull-down assays showed the direct binding of KLF4 to the KLF4-binding sites 2 and 3 of the T␤RI promoter and the recruitment of Smad2 to the Smad-responsive region. Formation of a stable KLF4-Smad2 complex in the promoter's Smad-responsive region mediated cooperative T␤RI promoter transcription in response to TGF-␤1. These results suggest that KLF4-dependent regulation of Smad and p38 MAPK signaling via T␤RI requires prior phosphorylation of KLF4 through Smad and p38 MAPK pathways. This study demonstrates a novel mechanism by which TGF-␤1 regulates VSMC differentiation. Proliferation of vascular smooth muscle cells (VSMCs)2 plays a key role in the pathogenesis of a variety of proliferative vascular diseases, such as atherosclerosis, restenosis, and hypertension (1, 2). Several lines of evidence have shown that the factors controlling VSMC proliferation and growth inhibition, including various growth factors, signal transduction molecules, and transcription factors, constitute a complex functional network. Krüppel-like factors (KLFs), retinoic acid receptor-␣, platelet-derived growth factor (PDGF) receptor, and T␤RI and T␤RII (transforming growth factor-␤ type I and II receptor, respectively) are expressed in VSMCs and are components of such a network (3-8). Our recent study demonstrates that KLF4 (GKLF) inhibits proliferation by PDGF receptor-mediated but not by retinoic acid receptor-␣-mediated phosphatidylinositol 3-kinase and ERK signaling in VSMCs (4). However, the actual relationship between KLF4 and T␤R in the regulation of VSMC proliferation and growth inhibition is not fully understood.KLF4 is a member of the Sp1 transcription factor family characterized by three C2H2 zinc finger motifs, mainly involved in regulating cell growth, differentiation, proliferation, and apoptosis, by controlling the expression of a large number of genes with GC/GT-rich promoters. KLF4 has been identified in VSMCs (9) and is induced by shear stress (10, 11), transforming growth factor-␤ (TGF-␤) (12), and PDGF-BB (13). Studies from the Owens laboratory (13) suggest that KLF4 not only mediates the repressive effects of PDGF-BB on VSMC gene expression but also represses the TGF-␤1-dependent increase...

Pediatric patients who received radiation therapy are at risk of developing side effects like radiogenic second cancer. We compared proton and photon therapies in terms of the predicted risk of second cancers for a 4-year-old medulloblastoma patient receiving craniospinal irradiation (CSI). Two CSI treatment plans with 23.4 Gy or Gy (RBE) prescribed dose were computed: a three-field 6-MV photon therapy plan and a four-field proton therapy plan. The primary doses for both plans were determined using a commercial treatment planning system. Stray radiation doses for proton therapy were determined from Monte Carlo simulations, and stray radiation doses for photon therapy were determined from measured data. Dose-risk models based on the Biological Effects of Ionization Radiation VII report were used to estimate risk of second cancer in eight tissues/organs. Baseline predictions of the relative risk for each organ were always less for proton CSI than for photon CSI at all attained ages. The total lifetime attributable risks of the incidence of second cancer considered after proton CSI and photon CSI were 7.7% and 92%, respectively, and the ratio of lifetime risk was 0.083. Uncertainty analysis revealed that the qualitative findings of this study were insensitive to any plausible changes of dose-risk models and mean radiation weighting factor for neutrons. Proton therapy confers lower predicted risk of second cancer than photon therapy for the pediatric medulloblastoma patient.

BackgroundPrimary or acquired resistance to cetuximab often occurs during targeted therapy in metastatic colorectal cancer (mCRC) patients. In many cancers, the key role of the long noncoding RNA (lncRNA) urothelial carcinoma-associated 1 (UCA1) in anticancer drug resistance has been confirmed. Emerging evidence has shown that specific exosomal lncRNAs may serve as meaningful biomarkers. In this study, we hypothesize that exosomal UCA1 might predict the response to cetuximab in CRC patients.MethodsFirst, acquired cetuximab-resistant cell lines were generated, and UCA1 expressions in these cells and their exosomes were compared. We also systematically evaluate the stability of exosomal UCA1. Thereafter, the predictive value of exosomal UCA1 in CRC patients treated with cetuximab was evaluated. Finally, through cell apoptosis assays and immunofluorescence staining, we analyzed the role of UCA1-containing exosomes in conferring cetuximab resistance.ResultsUCA1 expression was markedly higher in cetuximab-resistant cancer cells and their exosomes. Exosomal UCA1 was shown to be detectable and stable in serum from CRC patients. In addition, circulating UCA1-containing exosomes could predict the clinical outcome of cetuximab therapy in CRC patients, and UCA1 expression was considerably higher in the progressive disease/stable disease patients than in the partial response/complete response patients. Furthermore, exosomes derived from cetuximab-resistant cells could alter UCA1 expression and transmit cetuximab resistance to sensitive cells.ConclusionsWe discovered a novel role of UCA1-containing exosomes, showed their capability to transmit drug resistance and investigated their potential clinical use in predicting cetuximab resistance.

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