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Aim To establish the 3D hepatocyte model by selecting the humanized hepatocyte HepG2 cells and 3D cell culture methods, and to establish the 3D hepatocyte cytokinesis-block micronucleus cytome(CBMN-cyt)assay and 3D hepatocyte comet assay by using chemicals of different mode of action.Methods In this study, a scaffold-free culture method was used to successfully establish a 3D HepG2 hepatocyte spheroid model.The appearance of the sphere, the survival rate of cells inside the sphere, the gene expression of phase I and II metabolic enzymes, and the expression of liver-specific biomarkers were selected as the observation indicators to obtain the best culture conditions for the 3D hepatocyte model.The 3D hepatocyte model was combined with in vitro micronucleomics test and in vitro comet test to explore its applicability for genotoxicity test.Results The best culture conditions for the 3D hepatocyte model was 5×103 cells/20 μL /drop inoculation, cultivating for seven days.A 3D hepatocyte CBMN-cyt assay was established using mitomycin C(MMC), a micronucleus positive compound, and the results showed that it could successfully detect the genotoxicity and cytotoxicity of MMC.Compared with the CBMN-cyt results of 2D hepatocyte model, 3D hepatocyte model had higher sensitivity in detecting MN and Nbud.The 3D hepatocyte comet assay methods were established using the known in vivo and in vitro comet assay positive compound methyl methanesulfonate(MMS), and the results showed that MMS could significantly increase the tail DNA% of 3D hepatocytes with low cytotoxicity.The sensitivity of 3D hepatocyte model to MMS genotoxicity detection was higher than that of 2D cells.Conclusions The 3D hepatocyte model established in this study is easy to use and low in cost, and shows good sensitivity and specificity in the in vitro micronucleus test and comet test, suggesting that the 3D hepatocyte genotoxicity test method is used in early drug genotoxicity screening.It has good application prospects in additional experimental research.
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Objective: To explore the role and mechanism of long non-coding RNA RP11-159K7.2 in the progression of sinonasal squamous cell carcinoma (SNSCC). Methods: Sixty-five cases of SNSCC tissues and adjacent tissues were selected from the Department of Otorhinolaryngology Head and Neck Surgery, the Second Affiliated Hospital of Harbin Medical University from 2009 to 2014. The expression of RP11-159K7.2 in SNSCC and adjacent tissues was detected by RNAscope in situ hybridization to observe its association with prognosis. Clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR associated proteins 9 (CRISPR/Cas9) was used to knockout the expression of RP11-159K7.2 in RPMI-2650 cells (SNSCC cell line). Cell counting kit-8 (CCK-8), wound healing and Transwell were performed to observe the changes of proliferation, migration and invasion of SNSCC cells in vitro after down-regulation of RP11-159K7.2. Moreover, the growth of xenograft in nude mice after down-regulation of RP11-159K7.2 was examined in vivo. Mechanically, the protein chip, Western blot and RNA immunoprecipitation were performed to identify the proteins bound by RP11-159K7.2. SPSS 17.0 was used for statistical analysis. Results: The expression of RP11-159K7.2 in SNSCC tissue was significantly higher than that in adjacent tissues. RP11-159K7.2 expression was closely related with T grade, nodal metastasis and differentiation of SNSCC (χ2 value was 4.697, 4.235 and 10.753, respectively, all P<0.05). The five-year survival rate of RP11-159K7.2 high expression patients was significantly lower than that of RP11-159K7.2 low expression ones (P=0.013 7). After the down-regulation of RP11-159K7.2, the proliferation, migration and invasion ability of SNSCC cells decreased significantly, and the growth of SNSCC xenograft was significantly inhibited. There were 31 candidate proteins that may bind to RP11-159K7.2. RP11-159K7.2 directly bound to nuclear factor-κB (NF-κB) in SNSCC cells, and the regulation of RP11-159K7.2 on the proliferation and invasion of SNSCC cells depended on NF-κB. Conclusion: The increased expression of RP11-159K7.2 in SNSCC may serve as a potential molecular marker for SNSCC prognosis assessment. It is currently considered that the carcinogenic mechanism of RP11-159K7.2 in SNSCC is related to the regulation of NF-κB protein.