ABSTRACT
BACKGROUND: Long non-coding RNAs (lncRNAs) are key regulators of the 6-methyladenosine (m6A) epigenetic modification, playing a role in the initiation and progression of tumors. However, the regulatory mechanisms in head and neck squamous cell carcinoma (HNSCC) remain elusive. In this study, we investigated the molecular regulatory mechanisms of the lncRNA RASAL2-AS1 in the occurrence and development of HNSCC tumors. METHODS: A bioinformatics analysis was conducted to analyze the expression level of RASAL2-AS1 in HNSCC and normal tissues. RASAL2-AS1 mRNA and protein levels were detected using RT-PCR and Western blotting. Wound healing, transwell assays, flow cytometry, M6A dot blot, and RNA immunoprecipitation experiments were conducted to explore the regulatory role of the RASAL2-AS1 and downstream targets METTL14/LIS1 signaling pathway in HNSCC. Immunohistochemical examination was conducted to evaluate the expression of METTL14 and LIS1 in HNSCC and normal tissues. A tumor xenograft model of BALB/c nude mice was established to assess the impact of RASAL2-AS1 on cell proliferation and growth. RESULTS: RASAL2-AS1 high expression in HNSCC and cells deteriorated with survival rates of HNSCC. RASAL2-AS1 overexpression in HNSCC accelerated cell migration, colony formation, cell proliferation, cell cycle in S stage, while RASAL2-AS1 knockdown in HNSC cells inhibited cell cycle in G1 stage. After silencing METTL14, the above effects induced by overexpression of the RASAL2-AS1 were reversed. RASAL2-AS1 overexpression prompted LIS1 expression, whereas RASAL2-AS1 silencing reduced LIS1 levels in HNSCC cells, which was confirmed by immunohistological staining. Results demonstrated elevated expression of METTL14 or LIS1 in tongue cancer tissues. Overexpression of RASAL2-AS1 promoted tumor weight and tumor volume, which was counteracted by pcDNA3.1 RASAL2-AS1 plus silencing METTL14 and METTL14 and LIS1 were significantly decreased. CONCLUSION: Our study highlights the functional importance of the LncRNA RASAL2-AS1 in HNSCC and might assist in the development of a prognostic stratification and therapeutic approach. Which regulates HNSCC with the dependence of m6a manner.
ABSTRACT
In order to decrease the toxicity of paclitaxel (PTX) and increase the efficiency, we developed an amphiphilic PTX injection system using a biodegradable and biocompatible polymer synthesized by folic acid, cholesterol, and chitosan (FACC). This FACC-based polymer had a low critical concentration (64.13µg/ml) and could self-assemble in aqueous condition to form nanoscale micelles. The particle sizes of FACC-PTX micelles were 253.2±0.56 nm, the encapsulation efficiency and loading capacity of these FACC-PTX micelles were 65.1±0.23% and 9.1±0.16%, respectively. The cumulative release rate was about 85% at pH 5.0 which was higher than that at pH 7.4 (76%). This pH-dependent release behavior was highly suggesting that PTX release from FACC-PTX micelles might be higher in a weak acidic tumor microenvironment and lower toxic for normal cells. The anti-cancer effectiveness of FACC-PTX micelles was investigated by in vitro cytotoxicity and targeting study. The results revealed that FACC micelles have non-toxic on cells as evidenced by high cell viability found (86% to 100%) in the cells cultured with various concentrations of FACC micelles (1 to 500 µg/ml). Targeting study indicated that the cytotoxic efficacy of FACC-PTX micelles was significantly higher than that with Taxol® in the Hela cells (folate receptor-positive cells). These findings indicated that the anticancer efficiency of PTX can be enhanced by adding some cancer cell positive receptor into drug carrier and the FACC micelle was a potential tumor targeting carrier for PXT delivery.