Establishment of leukemia cell model with inducible AML1-ETO expression and its effect on fatty acid metabolism in leukemia cells / 中华血液学杂志

Objective: To investigate the effect of the AML1-ETO (AE) fusion gene on the biological function of U937 leukemia cells by establishing a leukemia cell model that induces AE fusion gene expression. Methods: The doxycycline (Dox) -dependent expression of the AE fusion gene in the U937 cell line (U937-AE) were established using a lentivirus vector system. The Cell Counting Kit 8 methods, including the PI and sidanilide induction, were used to detect cell proliferation, cell cycle-induced differentiation assays, respectively. The effect of the AE fusion gene on the biological function of U937-AE cells was preliminarily explored using transcriptome sequencing and metabonomic sequencing. Results: ①The Dox-dependent Tet-on regulatory system was successfully constructed to regulate the stable AE fusion gene expression in U937-AE cells. ②Cell proliferation slowed down and the cell proliferation rate with AE expression (3.47±0.07) was lower than AE non-expression (3.86 ± 0.05) after inducing the AE fusion gene expression for 24 h (P<0.05). The proportion of cells in the G(0)/G(1) phase in the cell cycle increased, with AE expression [ (63.45±3.10) %) ] was higher than AE non-expression [ (41.36± 9.56) %] (P<0.05). The proportion of cells expressing CD13 and CD14 decreased with the expression of AE. The AE negative group is significantly higher than the AE positive group (P<0.05). ③The enrichment analysis of the transcriptome sequencing gene set revealed significantly enriched quiescence, nuclear factor kappa-light-chain-enhancer of activated B cells, interferon-α/γ, and other inflammatory response and immune regulation signals after AE expression. ④Disorder of fatty acid metabolism of U937-AE cells occurred under the influence of AE. The concentration of the medium and short-chain fatty acid acylcarnitine metabolites decreased in cells with AE expressing, propionyl L-carnitine, wherein those with AE expression (0.46±0.13) were lower than those with AE non-expression (1.00±0.27) (P<0.05). The metabolite concentration of some long-chain fatty acid acylcarnitine increased in cells with AE expressing tetradecanoyl carnitine, wherein those with AE expression (1.26±0.01) were higher than those with AE non-expression (1.00±0.05) (P<0.05) . Conclusion: This study successfully established a leukemia cell model that can induce AE expression. The AE expression blocked the cell cycle and inhibited cell differentiation. The gene sets related to the inflammatory reactions was significantly enriched in U937-AE cells that express AE, and fatty acid metabolism was disordered.

Experimental study on expression of TH and GDNF bi-gene of lentivirus by improved Tet-On system for a rat model of Parkinson’ s disease / 中国药理学通报

Aim To investigate TH and GDNF genes expression and regulation of lentivirus ( Lv-TH-GDNF ) based on improved Tet-On system and the effect of the Lv-TH-GDNF intrastriatal transfer on a rat Parkinson’ s disease( PD) model. Methods 1. HeLa cells were infected by obtained Lv-TH-GDNF and rtTA2 s-M2 vi-rus. The expression of tyrosine hydroxylase ( TH ) and glial cell line-derived neurotrophic factor( GDNF) genes was induced by doxycycline( Dox) which was examined by Western blot. 2. The Lv-TH-GDNF together with rtTA2 s-M2 viruses were injected into lesion-side stria-tum of a rat PD model, and the expression of GDNF and TH genes was induced by Dox. Then, the effects of Lv-TH-GDNF were evaluated by the apomorphine-induced rotational behavior, the number of dopaminer-gic neurons in substantia nigra,DA and DOPAC levels in the lesion-side striatum. In addition, Western blot was performed to check the expression of TH and GD-NF genes in the transplanted striatum. Results 1. In vitro studies on HeLa cells, Western blot showed clear protein bands of TH and GDNF in the Dox-positive group, but not in the Dox-negative group. 2. In vivo experiments in animals, the results showed that, 4 weeks after transplantation, the apomorphine-induced turning effect was significantly improved ( P<0 . 01 ) , the number of TH-positive cells in the lesion-side sub-stantia nigra pars compacta as well as the content of DA and DOPAC, the protein level of GDNF and TH genes in the lesion-side striatum was significantly in-creased ( P<0 . 01 ) , each of which was only in Lv-TH-GDNF+rtTA2 s-M2+Dox-treated rats as compared with PBS-treated rats. Conclusion The expression of TH and GDNF genes in Lv-TH-GDNF based on im-proved Tet-On system is effectively regulated by tetra-cycline antibiotics without basal activity in vitro, and the intrastriatal transfer of which has certain therapeutic effect on PD rats.

Establishment of HepG2~(Tet-on) cell line controlled by the Tet-on regulatory system / 中国普通外科杂志

Objective To establish tetracycline-controlled inducible system(Tet-on) in HepG2 cell for further research of the function of related gens.Methods The HepG2 cells were transfected with pWHE146 vector by using liposome transfection reagent.The transfected cells were selected in medium containing G418,and G418-resistant clones were isolated.All individual G418-resistant clones were screened by transient transfection with plasmid pTRE-hyg-luc for clones with low background and high induction of luciferase in response to Dox.Results One HepG2 cell line,which exhibited high levels of induction(154,106 times)and high gene expression levels,was obtained.Conclusions The HepG2 cell line can be used to highly express eukaryotic gene and this Tet-on system is available for use in eukaryotic gene function studies.