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Background and Aims The development and progression of hepatocellular carcinoma (HCC) is dependent on its local microenvironment. Tumor‐associated macrophages (TAMs) are deemed a key factor for the tumor microenvironment and attribute to contribute to tumor aggressiveness. However, the detailed mechanism underlying the pro‐metastatic effect of TAMs on HCC remains undefined. Approach and Results The present study proved that TAMs were enriched in HCC. TAMs were characterized by an M2‐polarized phenotype and accelerated the migratory potential of HCC cells in vitro and in vivo. Furthermore, we found that M2‐derived exosomes induced TAM‐mediated pro‐migratory activity. With the use of mass spectrometry, we identified that integrin, αMβ2 (CD11b/CD18), was notably specific and efficient in M2 macrophage–derived exosomes (M2 exos). Blocking either CD11b and/or CD18 elicited a significant decrease in M2 exos–mediated HCC cell metastasis. Mechanistically, M2 exos mediated an intercellular transfer of the CD11b/CD18, activating the matrix metalloproteinase‐9 signaling pathway in recipient HCC cells to support tumor migration. Conclusions Collectively, the exosome‐mediated transfer of functional CD11b/CD18 protein from TAMs to tumor cells may have the potency to boost the migratory potential of HCC cells, thus providing insights into the mechanism of tumor metastasis.

A critical role of the Toll-like receptor(TLR) and its downstream molecules, including IL-1 receptor-associated kinase 1(IRAK1) and tumor necrosis factor receptor– associated factor 6(TRAF6), in the pathogenesis of liver ischemia/reperfusion (I/R) injury has been documented. Recently a microRNA, miR-146a, was identified as a potent negative regulator of the TLR signaling pathway. In this study, we investigated the role of miR-146a to attenuate TLR signaling and liver I/R injury in vivo and in vitro. miR-146a was decreased in mice Kupffer cells following hepatic I/R, whereas IRAK1 and TRAF6 increased. Overexpression of miR-146a directly decreased IRAK1 and TRAF6 expression and attenuated the release of proinflammatory cytokines through the inactivation of NF-κB P65 in hypoxia/reoxygenation (H/R)-induced macrophages, RAW264.7 cells. Knockdown experiments demonstrated that IRAK1 and TRAF6 are two potential targets for reducing the release of proinflammatory cytokines. Moreover, co-culture assays indicated that miR-146a decreases the apoptosis of hepatocytes after H/R. In vivo administration of Ago-miR-146a, a stable version of miR-146a in vivo, protected against liver injury in mice after I/R via inactivation of the TLR signaling pathway. We conclude that miR-146a ameliorates liver ischemia/reperfusion injury in vivo and hypoxia/reoxygenation injury in vitro by directly suppressing IRAK1 and TRAF6.

This study was expected to reveal the regulatory effects of lncRNA UCA1 on pancreatic cancer cell progression through targeting miR-96/FOXO3. Microarray analysis was carried out on 36 cases of pancreatic cancer tissues and 16 cases of adjacent tissues among them. Expression levels of lncRNA UCA1, miR-96, and FOXO3 in pancreatic cancer tissues and cell lines were determined by qRT-PCR. Expression levels of FOXO3 protein were determined by western blot. Cell viability, cell cycle and apoptosis, cell invasion and migration were detected by CCK-8, flow cytometry, and transwell assay, respectively. The colocalization relationship between lncRNA UCA1 and miR-96 was detected by RNA FISH. Whether UCA1 could target miR-96 and whether miR-96 could target FOXO3 3'UTR were verified by dual-luciferase reporter gene assay. High expression of lncRNA UCA1 and FOXO3 and low expression of miR-96 were shown in pancreatic cancer. Inhibition of UCA1 suppressed pancreatic tumor cell proliferation, colony formation, and metastasis, while inhibition of miR-96 promoted pancreatic cancer cell progression. FOXO3 was the downstream target gene of miR-96 and showed the opposite effects. LncRNA UCA1 promoted cell proliferation, invasion, migration and inhibited cell apoptosis of pancreatic cancer through down-regulating miR-96 and up-regulating FOXO3. © 2018 IUBMB Life, 70(4):276-290, 2018.

By investigating the migration and invasion ability in pancreatic cancer, this study probed into the lncRNA MALAT1 molecular mechanism on Hippo-YAP signaling. The expression of lncRNA MALAT1 in PC tissues and cells was detected by qRT-PCR and Western blot. The effect of si-MALAT1 on proliferation was determined by CCK-8 assay. Cell apoptosis, migration, and invasion were respectively detected by flow cytometry assay, wound healing assay, and transwell assay. Western blot and immunohistochemistry were successively used for detecting LATS1 and YAP1 expression in pancreatic cancer tissues. The microarray analysis determined that lncRNA MALAT1 in pancreatic cancer was highly expressed. LncRNA MALAT1 presented an extremely high expression level in pancreatic cancer tissues and cells. After transfected with si-MALAT1, the proliferation of AsPC-1 cells decreased, induce apoptosis of AsPC-1 cells, and migration and invasion ability were reduced. The tendency of LATS1 expression level was down-regulated and YAP1 show the opposite trend in the Hippo-YAP signaling. The in vivo assay was found that the tumor to be small in size and volume, and the expression of Ki-67 was decreased. High expression of lncRNA MALAT1 in PC disorder the proliferation, apoptosis, and migration and invasion ability via influence Hippo-YAP signaling pathway.

Abstract. Hepatocellular carcinoma (HCC) is the most common primary cancer of the liver and latexin is downregulated in several types of human cancer. However, latexin expression in HCC remains unknown. mRNA expression of latexin in HCC samples and HCC-derived cell lines was detected by semi-quantitative PCR and real-time PCR, while protein expression was assessed by immunohistochemistry. The role of latexin in the regulation of the proliferation of HCC-derived cells was investigated both in vitro and in vivo. Flow cytometry was used to differentiate cell cycle distribution in SK-hep-1 and YY-8103. In a total of 60 paired HCC specimens, compared with adjacent non-cancer tissues, latexin mRNA was downregulated in 42 specimens. Immunohistochemical analysis showed a significant reduction in latexin expression in HCC compared to control tissues. Overexpression of latexin inhibited SK-hep-1 and HepG2 cellular colony formation and tumor growth. Conversely, YY-8103 and Focus cells transfected with shRNA enhanced colony formation and tumor growth. Latexin overexpression promoted cell cycle arrest in the G0/G1 phase in SK-hep-1 and silencing of latexin promoted the cell cycle transition from G0/G1 phase to S phase in YY-8103. The cyclin-dependent kinase inhibitors (CDKIs) (p21Cip1, p27Kip1, p15INK4B), cyclin D1 and cyclin E were shown to be differentially expressed in latexin-overexpressed cells and latexin-silenced cells. These results indicated that latexin may be an effective target for gene therapy.

Background Hypoxia is a hallmark of cancer, and is closely intertwined with tumor immune evasion. Circular RNAs (circRNAs) have been implicated in tumor response to immune checkpoint blockades. However, hypoxia-associated circRNAs that orchestrate the association between hypoxia and response to immunotherapy remain poorly understood. Here, we aimed to determine the roles of hypoxia-associated circRNAs in immune escape of hepatocellular carcinoma (HCC) cells. Methods Differentially expressed hypoxia-associated circRNAs were determined using high-throughput sequencing technology. HCC patients treated with PD-1 blockade were enrolled to assess the clinical significance of circPRDM4. RT-qPCR, western blotting, flow cytometry, T cell-mediated tumor cell killing assay, and enzyme linked immunosorbent assay were used to investigate the roles of circPRDM4 in immune escape of HCC cells in vitro. Patient-derived xenograft mouse models and adoptive human tumor infiltrating lymphocyte-CD8+ T cell transfer were adopted to evaluate the effects of circPRDM4 in vivo. RNA pull-down, mass spectrometry, RNA immunoprecipitation, chromatin immunoprecipitation, chromatin isolation by RNA purification, dual-luciferase reporter assays, dot blotting, DNA in situ hybridization, and immunoprecipitation were utilized to examine the interaction between circPRDM4, HIF-1α, and CD274 promoter. Results We identified circPRDM4 as a hypoxia-associated circRNA in HCC. circPRDM4 was upregulated in responders to PD-1 blockade and associated with therapeutic efficacy. In vitro and in vivo experiments showed that circPRDM4 induced PD-L1 expression and promoted CD8+ T cell-mediated immune escape under hypoxic conditions. Mechanistically, circPRDM4 acted as a scaffold to recruit HIF-1α onto CD274 promoter, and cemented their interaction, ultimately promoting the HIF-1α-mediated transactivation of PD-L1. Conclusions These findings illustrated that circPRDM4 promoted immune escape of HCC cells by facilitating the recruitment of HIF-1α onto the promoter of CD274 under hypoxia, thereby inhibiting CD8+ T cell infiltration in the tumor microenvironment. This work may provide a novel prognostic biomarker and therapeutic candidate for HCC immunotherapy.

Abstract. Hepatocellular carcinoma (HCC) is the most common primary cancer of the liver. ) is known to be downregulated in several types of human cancer; however, the expression, function and underlying mechanisms of miR-497 in HCC remain unclear. Therefore, the present study investigated miR-497 expression in HCC samples and HCC-derived cell lines using reverse transcription-quantitative polymerase chain reaction. The protein expression of one of the predicted common targets of miR-497, insulin-like growth factor-1 receptor (IGF-1R), was assessed using western blot analyses and immunohistochemistry. The role of miR-497 in regulating the proliferation of HCC-derived cells was also investigated in vitro and in vivo. Of 60 paired specimens from HCC patients, miR-497 was downregulated in 42 cancer specimens compared with adjacent non-cancer tissues. Western blotting and immunohistochemical analyses revealed that IGF-1R expression was significantly increased in HCC compared to control tissues. In addition, overexpression of miR-497 was observed to inhibit colony formation and tumor growth in MHCC-97H human HCC cells. Conversely, SMMC-7721 human HCC cells transfected with a miR-497 inhibitor exhibited enhanced colony formation and tumor growth. Finally, IGF-1R protein, phosphoinositide 3-kinase/Akt signaling pathway-associated proteins and cyclin pathway-associated proteins were differentially expressed between miR-497-overexpressing cells and miR-497-silenced cells. These results indicate that miR-497 may be a potentially effective gene therapy target.