Long-chain non-coding RNA LOC554202 promotes proliferation, migration, and invasion of nasopharyngeal carcinoma cells by binding to microRNA-31 expression and regulating RhoA expression.

OBJECTIVE: Long-chain non-coding LOC554202, as a host gene for microRNA-31, has been shown to play a crucial role in a variety of diseases, especially tumors. However, its biological function in nasopharyngeal carcinoma (NPC) has not been reported. PATIENTS AND METHODS: The expression levels of LOC554202 and microRNA-31 in NPC tumor tissue samples and cell lines were detected by quantitative Real Time-Polymerase Chain Reaction (qRT-PCR). The impacts of LOC554202 and microRNA-31 on the biological functions of NPC cells were examined by Cell Counting Kit-8 (CCK-8) and transwell assays. In addition, the modulation of LOC554202 on the expressions of microRNA-31 and RhoA was further confirmed by qRT-PCR and Western blot analysis. RESULTS: The data of this study indicated that LOC554202 expression in NPC tissues and cell lines was remarkably upregulated, while microRNA-31 level showed an opposite tendency. Increasing LOC554202 expression remarkably enhanced the growth and metastasis of NPC cells, which was inhibited by overexpression of microRNA-31. Overexpression of LOC554202 downregulated microRNA-31 expression but upregulated that of RhoA, which may be a potential mechanism for the implication of LOC554202 in NPC. CONCLUSIONS: As a host gene of microRNA-31, LOC554202 enhances RhoA expression and thus promotes the proliferative capacity and invasiveness of NPC cells.

The toxicity of cadmium to three aquatic organisms (Photobacterium phosphoreum, Daphnia magna and Carassius auratus) under different pH levels.

This study investigated the effect of pH on cadmium toxicity to three aquatic organisms: Photobacterium phosphoreum, Daphnia magna and Carassius auratus. The acute toxicity of Cd(2+) to P. phosphoreum and D. magna at five pH values (5.0, 6.0, 7.0, 8.0, and 9.0) was assessed by calculating EC50 values. We determined that Cd(2+) was least toxic under acidic conditions, and D. magna was more sensitive to the toxicity of Cd than P. phosphoreum. To evaluate Cd(2+)-induced hepatic oxidative stress in C. auratus at three pH levels (5.0, 7.25, 9.0), the activity of antioxidant enzymes (superoxide dismutase, catalase and glutathione peroxidase), the level of glutathione and the malondialdehyde content in the liver were measured. Oxidative damage was observed after 7d Cd exposure at pH 9.0. An important finding of the current research was that Cd(2+) was generally more toxic to the three test organisms in alkaline environments than in acidic environments.