SPAG5 Activates PI3K/AKT Pathway and Promotes the Tumor Progression and Chemo-Resistance in Gastric Cancer.

The sperm-associated antigen 5 (SPAG5) is an important protein in mitosis and cell cycle checkpoint regulation, with more attention as a novel oncogene in various cancers. High level of SPAG5 expression has been detected in our clinical gastric cancer (GC) samples and The Cancer Genome Atlas GC data. However, the bio-function and potential mechanism of SPAG5 in GC remain unclear. In this study, we investigated the role of SPAG5 in GC development and the correlation between SPAG5 and 5-fluorouracil (5-FU) treatment. SPAG5 expression was increased in GC samples compared with that in normal tissues (80.8% vs. 22.0%), which was apparently associated with a worse outcome. Biological experiments showed that knockdown of SPAG5 induced apoptosis and suppressed proliferation in cells and animal models. Downregulation of SPAG5 enhanced the sensitivity of 5-FU in GC cells. Gene microarray chip identified 856 upregulated and 787 downregulated genes in SPAG5 silencing cells. Furthermore, 12 significant genes, including CDKN1A, CDKN1B, EIF4E, MAPK1, and HSP90B1, belonged to the PI3K/AKT signaling pathway using ingenuity pathway analysis. Meanwhile, real-time PCR and Western blotting results showed that knockdown of SPAG5 inhibited PI3K/AKT signaling pathway. Collectively, SPAG5 promotes the growth of GC cells by regulating PI3K/AKT signaling pathway, which could be the promising target gene in GC therapy.

Podofilox suppresses gastric cancer cell proliferation by regulating cell cycle arrest and the c-Myc/ATG10 axis.

Gastric cancer (GC) is a malignancy for which effective therapeutic drugs are limited. Podofilox exhibits antitumor effects in various types of cancer; however, whether it may inhibit GC growth remains unknown. The aim of the present study was to investigate the role of podofilox in GC. Cell Counting Kit-8, colony formation and cell cycle assays were used to detect the role of podofilox on cellular proliferation and the cell cycle, respectively. A microarray was used to detect the transcriptional changes induced by podofilox in GC cells. The results of the present study demonstrated that podofilox inhibited GC cell proliferation and colony formation. The half maximal inhibitory concentration of podofilox in AGS and HGC-27 cells was 2.327 and 1.981 nM, respectively. In addition, treatment with podofilox induced G0/G1 cell cycle arrest. Molecular analysis based on microarray data demonstrated that podofilox altered the expression levels of genes involved in the cell cycle, c-Myc and p53 signaling. Autophagy-related 10 (ATG10), which was highly expressed in GC tissues, was also downregulated by podofilox, as demonstrated by the results of the microarray analysis and immunoblotting. To determine the involvement of ATG10 in GC, ATG10 was knocked down in GC cells by small interfering RNA, which suppressed the proliferation and colony formation of GC cells compared with those observed in the control-transfected cells. Taken together, the results of the present study suggested that podofilox may inhibit GC cell proliferation by preventing the cell cycle progression and regulating the c-Myc/ATG10 signaling pathway.

Interference of Hsa_circ_0003928 Alleviates High Glucose-Induced Cell Apoptosis and Inflammation in HK-2 Cells via miR-151-3p/Anxa2.

BACKGROUND: Diabetic nephropathy (DN) is a severe end-stage kidney disease developed from diabetes mellitus. The involvement of circular RNA (circRNAs) in the regulation of DN pathogenesis has been implied, but the underlying mechanism of DN is still lacking. This study aimed to investigate the effect of hsa_circ_0003928 on the inflammation and apoptosis of high glucose (HG)-induced renal tubular cells. METHODS: The expression of hsa_circ_0003928, miR-151-3p and Anxa2 in blood samples from DN patients and healthy controls was detected by RT-qPCR. Human renal epithelial cells HK-2 were incubated with D-glucose (30 mmol/l) to establish DN model in vitro. RT-qPCR analysis confirmed the transfection effects and detected the expressions of TNF-α, IL-6 and IL-1ß. Western blotting analysis determined the protein expression of Anxa2, Bcl-2, Bax, cleaved caspase-3 and caspase-3. The production of ROS was detected by DCF-DA method and production of inflammatory cytokines was verified by ELISA assay. CCK-8 assay and TUNEL assay were performed to determine cell viability and apoptosis, respectively. Dual-luciferase reporter assay was performed to confirm the relationship between miR-151-3p and hsa_circ_0003928 or Anxa2. RESULTS: Hsa_circ_0003928 and Anxa2 mRNA levels were increased, whereas miR-151-3p was decreased in both HG-induced HK-2 cells and patients with DN. Hsa_circ_0003928 knockdown could decrease cell viability loss and apoptosis, increase Bcl-2 expression, and decrease Bax and cleaved caspase-3 expression. Besides, hsa_circ_0003928 knockdown suppressed HG-induced overproduction of ROS, TNF-α, IL-6 and IL-1ß. However, the effects made by miR-151-3p inhibition were opposite to those made by hsa_circ_0003928 knockdown. Furthermore, the binding sites between miR-151-3p and hsa_circ_0003928 or Anxa2 were predicted and verified. Protein expression of Anxa2 was suppressed by hsa_circ_0003928 knockdown, which was rescued by miR-151-3p inhibition. CONCLUSION: These results demonstrated that hsa_circ_0003928 could act as a sponge of miR-151-3p and regulate HG-induced inflammation and apoptosis partly through regulating Anxa2.