MiR-99a suppresses cell invasion and metastasis in nasopharyngeal carcinoma through targeting HOXA1.

BACKGROUND: Recent studies reported that miRNAs play important roles in the carcinogenesis and progression of nasopharyngeal carcinoma (NPC). Therefore, further studies are warranted to better elucidate the function and mechanism of miRNAs in NPC. METHODS: Quantitative reverse transcription-polymerase chain reaction (RT-PCR) was used to detect the miR-99a expression in NPC cell lines and tissue samples. Wound healing, transwell migration and invasion, and lung metastatic colonization assays were performed to determine NPC cell migratory, invasive and metastatic abilities of NPC cells. Luciferase reporter assays, quantitative RT-PCR and Western blotting were used to validate the target of miR-99a. RESULTS: We found that miR-99a was significantly downregulated in NPC cell lines and tissue samples. Ectopic overexpression of miR-99a significantly inhibited NPC cell migration and invasion in vitro, and suppressed lung macroscopic and microscopic metastatic colonization in vivo. Conversely, silencing of miR-99a significantly promoted the migratory and invasive abilities of NPC cells. Furthermore, HOXA1 was validated as a direct target of miR-99a, and ectopic expression of HOXA1 could rescue the suppressive effect of miR-99a overexpression on NPC cell migration and invasion. CONCLUSION: Together, these results indicated that miR-99a could inhibit NPC invasion and metastasis by targeting HOXA1, thus providing a novel potential target for miRNA-based treatment for NPC patients in the future.

Anti-proliferative and pro-apoptotic effect of carvacrol on human hepatocellular carcinoma cell line HepG-2.

Carvacrol is one of the members of monoterpene phenol and is present in the volatile oils of Thymus vulgaris, Carum copticum, origanum and oregano. It is a safe food additive commonly used in our daily life, and few studies have indicated that carvacrol has anti-hepatocarcinogenic activities. The rationale of the study was to examine whether carvacrol affects apoptosis of human hepatoma HepG2 cells. In this study, we showed that carvacrol inhibited HepG2 cell growth by inducing apoptosis as evidenced by Hoechst 33258 stain and Flow cytometric (FCM) analysis. Incubation of HepG2 cells with carvacrol for 24 h induced apoptosis by the activation of caspase-3, cleavage of PARP and decreased Bcl-2 gene expression. These results demonstrated that a significant fraction of carvacrol treated cells died by an apoptotic pathway in HepG2 cells. Moreover, carvacrol selectively altered the phosphorylation state of members of the MAPK superfamily, decreasing phosphorylation of ERK1/2 significantly in a dose-dependent manner, and activated phosphorylation of p38 but not affecting JNK MAPK phosphorylation. These results suggest that carvacrol may induce apoptosis by direct activation of the mitochondrial pathway, and the mitogen-activated protein kinase pathway may play an important role in the antitumor effect of carvacrol. These results have identified, for the first time, the biological activity of carvacrol in HepG2 cells and should lead to further development of carvacrol for liver disease therapy.

Parathion degradation and its intermediate formation by Fenton process in neutral environment.

The purpose of this study is to investigate parathion degradation by Fenton process in neutral environment. The initial parathion concentration for all the degradation experiments was 20 ppm. For hydrogen ion effect on Fenton degradation, the pH varied from 2 to 8 at the [H2O2] to [Fe²(+)] ratio of 2-2 mM, and the result showed pH 3 as the most effective environment for parathion degradation by Fenton process. Apparent degradation was also observed at pH 7. The subsequent analysis for parathion degradation was conducted at pH 7 because most environmental parathion exists in the neutral environment. Comparing the parathion degradation results at various Fenton dosages revealed that at Fe²(+) concentrations of 0.5, 1.0 and 1.5 mM, the Fenton reagent ratio ([H2O2]/[Fe²(+)]) for best-removing performance were found as 4, 3, and 2, resulting in the removal efficiencies of 19%, 48% and 36%, respectively. Further increase in Fe²(+) concentration did not cause any increase of the optimum Fenton reagent ratio for the best parathion removal. The result from LC-MS also indicated that hydroxyl radicals might attack the PS double bond, the single bonds connecting nitro-group, nitrophenol, or the single bond within ethyl groups of parathion molecules forming paraoxons, nitrophenols, nitrate/nitrite, thiophosphates, and other smaller molecules. Lastly, the parathion degradation by Fenton process at the presence of humic acids was investigated, and the results showed that the presence of 10 mg L⁻¹ of humic acids in the aqueous solution enhanced the parathion removal by Fenton process twice as much as that without the presence of humic acids.