Effect of Inhibiting Upstream Transcription Factor 2 Expression on Proliferation and Apoptosis of Gastric Cancer BGC-823 Cells / 肿瘤防治研究

Objective To investigate the effect of upstream transcription factor 2 (USF2) on the proliferation and apoptosis of human gastric cancer BGC-823 cells. Methods Lipofectamine?3000 transfection reagent was used to transfect USF2 siRNA into BGC-823 cells (siRNA-USF2 group). Blank control and negative control (siRNA-NC) groups were also prepared. The mRNA and protein expression levels of USF2 in transfected BGC-823 cells were detected by real-time fluorescence quantitative PCR and Western blot, respectively. The proliferation and clone formation abilities of BGC-823 cells in each group were investigated by CCK-8 and plate cloning assay. The apoptosis of gastric cancer cells was examined by flow cytometry. The expression levels of PCNA and apoptosis-related proteins Bax and Bcl-2 in BGC-823 cells were measured by Western blot. Results Compared with those in the blank control and siRNA-NC groups, the mRNA and protein expression levels of USF2 significantly decreased in the siRNA-USF2 group (P < 0.05). At 72 h after transfection, the absorbance in the siRNA-USF2 group was lower than that in the blank control group (P < 0.05). Compared with that in the blank control and siRNA-NC groups, the number of BGC-823 cell clones significantly decreased in the siRNA-USF2 group (P < 0.05). The apoptosis rate of BGC-823 cells significantly differed among the blank control, siRNA-NC, and siRNA-USF2 groups (P < 0.05). Compared with those in the blank control and siRNA-NC groups, the expression of PCNA and Bcl-2 protein decreased and that of Bax protein increased in the siRNA-USF2 group (P < 0.05). Conclusion Inhibiting USF2 expression can suppress the proliferation of human gastric cancer cells and induce their apoptosis. USF2 inhibitors may have important value in the treatment of gastric cancer.

Differential expression of upstream stimulatory factor (USF) 2 variants in eutopic endometria from women with endometriosis: estradiol regulation

BACKGROUND: Endometriosis, pro-inflammatory and invasive benign disease estrogen dependent, abnormally express in endometria the enzyme P450Arom, positively regulated by steroid factor-1 (SF-1). Our objective was to study the nuclear protein contents of upstream stimulating factor 2 (USF2a and USF2b), a positive regulator of SF-1, throughout the menstrual cycle in eutopic endometria from women with and without (control) endometriosis and the involvement of nuclear estrogen receptors (ER) and G-coupled protein estrogen receptor (GPER)-1. RESULTS: Upstream stimulating factor 2 protein contents were higher in mid (USF2b) and late (USF2a and USF2b) secretory phase in eutopic endometria from endometriosis than control (p < 0.05). In isolated control epithelial cells incubated with E2 and PGE2, to resemble the endometriosis condition, the data showed: (a) significant increase of USF2a and USF2b nuclear protein contents when treated with E2, PPT (specific agonist for ERa) or G1 (specific agonist for GPER1); (b) no increase in USF2 binding to SF-1 E-Box/DNA consensus sequence in E2-treated cells; (c) USF2 variants protein contents were not modified by PGE2; (d) SF-1 nuclear protein content was significantly higher than basal when treated with PGE2, E2 or G1, stimulation unaffected by ICI (nuclear ER antagonist); and (e) increased (p < 0.05) cytosolic protein contents of P450Arom when treated with PGE2, E2, PPT or G1 compared to basal, effect that was additive with E2 + PGE2 together. Nevertheless, in endometriosis cells, the high USF2, SF-1 and P450Arom protein contents in basal condition were unmodified. CONCLUSION: These data strongly suggest that USF2 variants and P450Arom are regulated by E2 through ERa and GPER1, whereas SF-1 through GPER1, visualized by the response of the cells obtained from control endometria, being unaffected the endogenously stimulated cells from endometriosis origin. The lack of E2 stimulation on USF2/SF-1 E-Box/DNA-sequence binding and the absence of PGE2 effect on USF2 variants opposite to the strong induction that they exert on SF1 and P450 proteins suggest different mechanisms and indirect regulations. The sustained USF2 variants protein expression during the secretory phase in eutopic endometria from women with endometriosis may participate in the pathophysiology of this disease strongly associated with infertility and its characteristic endometrial invasion to ectopic sites in the pelvic cavity.

Effects of USF-1, USF-2, PTEN and Thyroid Transcription Factors on the Function and Growth in FRTL-5 Cells / 대한내분비학회지

BACKGROUND: Upstream stimulatory factors (USFs) and PTEN are known to be tumor suppressants. USFs and PAX-8 were reported to be the functional competitors in sodium iodide symporter (NIS) gene expression. We investigated the effects of USF-1, USF-2, PTEN, and thyroid-specific transcription factors (TTF-1, PAX-8) on the function and growth of thyrocytes of FRTL 5 rat thyroid cells. METHODS: Complementary DNAs of the USF-1, USF-2, PTEN, TTF-1 (homeodomain), and PAX-8 were synthesized from RNA extracted from FRTL-5using an RT-PCR kit. Each of them was transiently transfected to the FRTL-5 cells using the lipofectamine after being cloned into the pcDNA3.1 vectors. Stable cell lines, which were transfected by USF-1, PTEN, TTF-1, and PAX-8, were also obtained from the FRTL-5 cells, respectively. Extracellular cAMP concentrations were measured after 24 hours of incubation with varying concentrations of bTSH (0.1~100 mIU/mL). After, [Methyl-3H] thymidine uptake or 5-bromo-2'-deoxyuridine (BrdU) assay was performed. RESULTS: USF-1 and USF-2 significantly increased cAMP levels and decreased thymidine uptake in both transiently and stably transfected cells (p<0.01). PTEN had a tendency to increase both the cAMP levels and BrdU uptake in stable cells, but had a tendency to decrease thymidine uptake in transiently transfected cells. TTF-1 significantly increased the cAMP levels and either thymidine or BrdU uptake in both transiently and stably transfected cells (p<0.05). PAX-8 significantly increased both the cAMP levels and BrdU assay in stable cells, but in transiently transfected cells, it significantly decreased cAMP concentrations (p<0.01). CONCLUSIONS: These results suggested that both the USF-1 and USF-2 play a role in suppressing the growth of thyrocytes but at the same time, they kept the ability to produce cAMP after TSH stimulation. They had opposing effects on TTF-1 and PAX-8 in terms of the proliferation of thyrocytes