ARTN-GFRA3 axis induces epithelial-mesenchymal transition phenotypes, migration, and invasion of gastric cancer cells via KRAS signaling.

Neural invasion underlies the local spread of gastric cancer and is associated with poor prognosis. This process has been receiving increasing attention in recent years. However, the relationship between neural invasion and the malignant phenotypes of gastric cancer cells, as well as the molecular mechanism involved in this process, remain unclear. In this study, bioinformatics analysis was performed using a dataset obtained from The Cancer Genome Atlas-Stomach Adenocarcinoma. The results revealed that high expression of GDNF family receptor alpha 3 (GFRA3) was associated with a poor prognosis of patients with gastric cancer. GFRA3 is a receptor for artemin (ARTN), a glial cell line-derived neurotrophic factor (GDNF). This association was indicated by short overall/disease-free survival, as well as the presence of high-stage and high-grade disease. Gene set enrichment analysis showed that two cancer-associated pathways, namely KRAS signaling and epithelial-mesenchymal transition (EMT), were activated when GFRA3 was highly expressed in gastric cancer. Further studies confirmed that GFRA3 activated KRAS downstream signaling phosphatidylinositol 3 kinase/protein kinase B (PI3K/AKT) or extracellular signal-regulated kinase (ERK) and induced EMT markers, as well as promoted the migration and invasion of gastric cancer cells. As a ligand of GFRA3, ARTN induced the EMT, migration, and invasion of gastric cancer cells via GFRA3. Notably, the effects of the ARTN-GFRA3 axis were attenuated by treatment with a KRAS inhibitor. The present findings indicated that, during the neural invasion of gastric cancer, ARTN-mediated activation of GFRA3 induces EMT phenotypes, migration, and invasion of gastric cancer cells via KRAS signaling.

Role of LncRNA MIR99AHG in breast cancer: Bioinformatic analysis and preliminary verification.

Objective: This research was aimed to preliminarily explore the clinical roles and potential molecular mechanisms of MIR99AHG and its significant transcripts in breast cancer (BRCA). Methods: Public databases were utilized to analyze the expression and prognostic roles of MIR99AHG and its transcripts. Relationships between MIR99AHG expression and immune cells infiltration were analyzed in Xiantao platform. In addition, co-expressed genes and interacting proteins of MIR99AHG were predicted. CancerSEA analyzed its relationship with functional states. Next, CNV status, DNA methylation, interacting transcription factors (TFs) and ceRNA network were analyzed to explore its possible mechanisms. Then, RNA ISH and FISH assays were used to detect its expression and location in BRCA tissues and cell lines, respectively. Finally, qRT-PCR was utilized to investigate MIR99AHG expression in cell lines. Results: Compared with the corresponding normal tissues, MIR99AHG expression levels were lower in all BRCA subtypes, and luminal B's was the lowest one. And MIR99AHG expression was negatively related to the tumor stage. In addition, 4 transcripts (ENST00000619222.4, ENST00000418813.6, ENST00000602901.5 and ENST00000453910.5) of MIR99AHG showed significant differences in the expression. Databases also suggested that the high MIR99AHG expression levels indicated good prognosis, especially in patients without lymph node metastasis. Xiantao found that MIR99AHG was positively related to 17 immune cells and negatively linked with 2 immune cells. CancerSEA analysis showed no relationships between MIR99AHG and functional states. From GEPIA and BCIP databases, 19 co-expressed genes were highly related to these four significant transcripts of MIR99AHG. StarBase, RNAct and HDOCK showed that several tumor-associated proteins, including U2AF65, hnRNPC, AEBP2, CHIC1 and so on, might interact with MIR99AHG. Genetically, BRCA had a higher proportion of MIR99AHG CNV loss than CNV gain, and the high level of DNA methylation indicated a good prognosis. Furthermore, 19 TFs were predicted to combine with the promoter of MIR99AHG. Then, we screened out 10 miRNAs potentially interacting with the significant transcripts of MIR99AHG, and five were significantly increased in breast tumors compared to normal tissues, including miR-194-5p, miR-320 b and so on, which could combine 14 mRNAs. Through ISH and FISH assays, we verified that MIR99AHG was down-regulated in BRCA samples and cell lines in comparison to non-tumor tissues and mammary epithelial cell line (MCF10A), and MIR99AHG was located both in cytoplasm and nucleus. qRT-PCR assay also showed the lower expression of MIR99AHG in breast cancer cells than that in MCF10A. Conclusion: These results indicate that MIR99AHG can be a favorable prognostic indicator for BRCA. ENST00000619222.4, ENST00000418813.6, ENST00000602901.5 and ENST00000453910.5 are significant transcripts and their down-regulation may play crucial roles in the progression of BRCA.

Adenovirus-mediated ING4 expression reduces multidrug resistance of human gastric carcinoma cells in vitro and in vivo.

Chemotherapy is the primary treatment for both resectable and advanced gastric carcinoma, yet multiple drug resistance (MDR) of gastric carcinoma remains a significant therapeutic obstacle. The development of novel strategies to reduce MDR in gastric carcinoma would yield a better outcome following chemotherapy. ING4, a member of the inhibitor of growth (ING) tumor-suppressor family, possesses antitumor and radiosensitization or chemosensitization effects in a variety of human cancers. The present study investigated the effects and possible mechanisms of action of adenovirus-mediated ING4 (AdVING4) on the reversion of human gastric carcinoma cell MDR in vitro and in vivo in nude mouse xenografts. The data showed that the expression of ING4 mRNA and protein was dramatically downregulated (or lost) in gastric carcinoma SGC7901/CDDP cells after CDDP-induced MDR phenotype and in the parental SGC7901 cells. AdVING4­induced ING4 expression reversed MDR and induced apoptosis of SGC7901/CDDP cells in vitro and in vivo in the SGC7901/CDDP xenograft tumors. Furthermore, AdVING4 substantially downregulated the expression of MDR-related proteins P-gp and MRP1 and apoptosis­related proteins Bcl-2 and survivin, but upregulated the expression of apoptosis-related protein Bax in the SGC7901/CDDP xenograft tissues. The reversion effects elicited by AdVING4 on gastric cancer cell MDR were closely associated with the downregulation of ATP-binding cassette transporters and activation of apoptotic pathways. Thus, these findings suggest that AdVING4 may be a feasible modulator for the MDR phenotype of gastric carcinoma cells.

[A research of stability method for non-dispersive infrared gas analysis based on multi-parameter model].

To non-dispersive infrared gas analysis, it was the most difficult challenge to maintain very low zero and temperature drift over long periods. Electronic and detector response drifts irremediably required some form of manual zeroing procedure. To solve zero and temperature drift, a multi-parameters model was developed, by which zero and temperature drifts were automatically corrected. These parameters include zero gas intensity, reference channels intensity, standard temperature, environment temperature, temperature drift coefficients etc. Trial results and in-situ applications showed that the monitoring precisions of the instrument were lesser than 5% F. S in different temperatures and for a long time. The average precision of monitoring carbon monoxide concentration increased respectively from 9.26 to 1.23%, and monitoring hydrocarbon concentration from 10.61% to 0.70% before and after compensated. The instrument required essentially no periodic calibration and have very low maintenance cost.