Chemotherapy is an important treatment option for gastric cancer (GC); however, chemotherapy usually fails due to drug resistance, particularly multidrug resistance (MDR). In our previous studies, microRNA (miR)-874 was demonstrated to serve an important role in tumour growth, apoptosis and angiogenesis. In the present study, the precise roles and underlying mechanisms of miR-874 in MDR were investigated in GC. The overexpression of miR-874 reversed cancer cell drug resistance in vitro. According to reporter gene and western blot assays, Autophagy-related 16-like 1 (ATG16 L1) was identified as a direct target of miR-874. ATG16L1 was also demonstrated to be positively associated with autophagy. Reducing the expression of ATG16L1 and inhibiting the occurrence of autophagy sensitized GC cells to chemotherapy. Thus, the miR-874/ATG16L1/autophagy regulatory loop was demonstrated to serve an important role in MDR in GC. Furthermore, miR-874 may be used as a prognostic factor in GC. Overall, miR-874 could inhibit autophagy and sensitize GC cells to chemotherapy via the target gene ATG16L1, highlighting the potential clinical application of miR-874 in chemotherapeutic resistance.

Hepatocellular carcinoma (HCC) remains the fifth most frequent cancer with high mortality rate worldwide. However, the underlying molecular mechanisms of HCC progression are still barely known. Long noncoding RNAs (lncRNAs) have been recognized as significant therapeutic targets for HCC. Recently, the biological role of LINC00857 in several cancer types has been reported. Our present study was aimed to investigate the role of LINC00857 in HCC progression. We observed that LINC00857 was overexpressed in HCC cell lines (Huh7, Hep3B, HepG2, MHCC‐97H, and SNU449). Knockdown of LINC00857 significantly repressed Hep‐3B and SNU449 cell proliferation and inhibited the HCC cell colony formation. In addition, cell apoptosis was induced by the silence of LINC00857 and cell cycle progression was blocked in G1 phase. Besides these, downregulation of LINC00857 was able to restrain HCC cell migration and invasion capacity via enhancing epithelial‐mesenchymal transition (EMT) process. As displayed, E‐cadherin protein expression was increased by LINC00857 silence, while N‐cadherin protein level was repressed by LV‐shLINC00857 in HCC cells. Finally, the in vivo assays were used and the data indicated that LINC00857 could also obviously suppress the HCC tumor growth in vivo. In conclusion, our study revealed that LINC00857 might provide a novel perspective for the HCC treatment.

LncRNAs exhibit crucial roles in various pathological diseases, including hepatocellular carcinoma (HCC). Therefore, it is significant to recognize the dysregulated lncRNAs in HCC progression. Recently, LINC01133 has been identified in several tumors. However, the biological role of LINC01133 in HCC remains poorly understood. Currently, we focused on the function of LINC01133 in HCC development. We observed that LINC01133 was significantly increased in HCC cells including HepG2, Hep3B, MHCC-97L, SK-Hep-1, and MHCC-97H cells compared with the normal human liver cell line HL-7702. In addition, PI3K/AKT signaling was highly activated in HCC cells. Knockdown of LINC01133 was able to inhibit HCC cell proliferation, cell colony formation, cell apoptosis, and blocked cell cycle arrest in the G1 phase. For another, downregulation of LINC01133 repressed HCC cell migration and invasion. Subsequently, the PI3K/AKT signaling pathway was strongly suppressed by silence of LINC01133 in Hep3B and HepG2 cells. Then, in vivo tumor xenografts models were established using Hep3B cells to explore the function of LINC01133 in HCC progression. Consistently, our study indicated that knockdown of LINC01133 dramatically repressed HCC tumor progression through targeting the PI3K/AKT pathway in vivo. Taken these together, we revealed that LINC01133 contributed to HCC progression by activating the PI3K/AKT pathway. K E Y W O R D S hepatocellular carcinoma (HCC), LINC01133, PI3K/AKT signaling pathway J Cell Biochem. 2019;120:4172-4179. wileyonlinelibrary.com/journal/jcb 4172 |

Increasing studies have indicated that long noncoding RNAs (lncRNAs) exert important roles in hepatocellular carcinoma (HCC). Therefore, it is of great significance to identify the dysregulated lncRNAs in HCC. According to the previous reports, it has been suggested that DiGeorge syndrome critical region gene 5 (DGCR5) might participate in HCC and can serve as potential biomarker for HCC. In our current study, we concentrated on the biological function and roles of lncRNA‐DGCR5 in HCC. It was indicated that DGCR5 was decreased in HCC tissues and HCC cells including HepG2, Hep3B, MHCC‐97L, SNU‐449, and SNU‐182 cells compared with the normal human liver cell line LO2. Overexpression of DGCR5 was able to restrain HCC growth, migration, and invasion capacity in HepG2 and SNU‐449 cells. In addition, whether lncRNA‐DGCR5 can regulate Wnt/β‐catenin pathway during HCC progression is unclear. In our study, it was found that upregulation of DGCR5 inactivated Wnt signaling pathway through inhibiting β‐catenin, cyclin D1 and increasing GSK‐3β levels. Subsequently, in vivo tumor xenografts were established using HepG2 cells to investigate the function of DGCR5 in HCC development. Inconsistent with the in vitro findings, increase of DGCR5 dramatically suppressed HCC tumor progression in vivo. Taken these together, it was uncovered in our research that DGCR5 could play tumor suppressive role by targeting Wnt signaling in HCC progression.

Long noncoding RNAs (lncRNAs) have been demonstrated to play significant roles in hepatocellular carcinoma (HCC) tumor progression. LINC01433 has been implicated in the progression of lung cancer. However, its biological role in HCC remains poorly understood. In our current study, we focused on the detailed mechanism of LINC01433 in HCC development. First, it was exhibited that LINC01433 was remarkably elevated in HCC cells, which indicated that LINC01433 was involved in HCC. Then, knockdown of LINC01433 was able to restrain HCC cell proliferation and cell colony formation and greatly induced cell apoptosis. On the contrary, overexpression of LINC01433 promoted HCC cell proliferation, increased cell colony formation, and enhanced cell invasion capacity. Subsequently, we found that miR-1301 was remarkably decreased in HCC cells, and it can serve as a target of LINC01433 according to bioinformatics analysis. In addition, the binding correlation between them was validated by performing RNA pull-down experiments and RIP assay. Moreover, STAT3 was predicted and validated as a target of miR-1301, and it was shown that miR-1301 mimics significantly suppressed STAT3 in HCC cells.Finally, in vivo models were established, and the results demonstrated that silencing of LINC01433 could repress HCC development through modulating miR-1301 and STAT3. Taken together, these results indicated in our study that LINC01433 participated in HCC progression through modulating the miR-1301/STAT3 axis and it might act as a novel biomarker in HCC diagnosis and treatment.