[Effect and mechanism of siRNA targeting α-enolase gene combined with paclitaxel on proliferation, invasion and apoptosis of hepatocellular carcinoma cell]

Objective: To investigate the effect of siRNA targeting inhibition of α-enolase (ENO1) combined with paclitaxel on the proliferation, invasion and apoptosis of hepatocellular carcinoma SK-HEP-1 cell and its mechanism. Methods: siRNA-ENO1 (siRNA-ENO1 group) and siRNA-negative control (siRNA-NC group) were transfected into SK-HEP-1 cells in vitro, the untransfected SK-HEP-1 cells were used as the control group, and the transfection effect was detected by real-time fluorescent quantitative polymerase chain reaction and western blotting. After SK-HEP-1 cells were treated with 0, 2.5, 5, 10, 20 and 40 μg/L paclitaxel for 48 hours, the cell survival rate was measured by 3-(4, 5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2H tetrazolium bromide (MTT) method and the semi inhibitory concentration of paclitaxel was calculated. SK-HEP-1 cells transfected with siRNA-ENO1 or siRNA-NC were treated with 10 μg/L paclitaxel as paclitaxel+ siRNA-ENO1 group and paclitaxel+ siRNA-NC group. The proliferation, clonogenesis, invasion and apoptosis of siRNA-NC group, siRNA-ENO1 group, paclitaxel+ siRNA-ENO1 group and paclitaxel+ siRNA-NC group were detected by MTT, clonogenesis, Transwell chamber and flow cytometry respectively. The expression levels of the phosphorylation of phosphatidylinositol-3-kinase (p-PI3K), p-protein kinase B (Akt) and proliferating cell nuclear antigen (PCNA), matrix metalloproteinase 9 (MMP-9) and B lymphocytoma-2 gene (Bcl-2) were detected by western blotting. Results: Compared with the control group (1.00±0.00 and 0.69±0.04, respectively), the expression levels of ENO1 mRNA and protein (0.25±0.03 and 0.23±0.02, respectively) in siRNA-ENO1 group decreased significantly (P<0.05), but there were no significant differences in the expression levels of ENO1 mRNA and protein in siRNA-NC group (P>0.05). Compared without treatment group [(100.00±0.00)%, P<0.05], the survival rates of SK-HEP-1 cells treated with 2.5, 5, 10, 20 and 40 μg/L paclitaxel [(88.65±6.46)%, (72.36±6.08)%, (60.48±4.23)%, (38.52±3.56)% and (20.75±2.32)%, respectively] decreased significantly (P<0.05), and the semi inhibitory concentration of paclitaxel was 13.26 μg/L. The cell survival rate and clone formation rate of siRNA-ENO1 group [(68.86±5.12)% and (18.12±2.25)%, respectively] were lower than those of siRNA-NC group [(100.00±0.00)% and (29.65±3.06)%, respectively, P<0.05]. The cell survival rate and clone formation rate of the paclitaxel+ siRNA-ENO1 group [(43.28±2.64)% and (8.72±0.52)%, respectively] were significantly different from those of the paclitaxel+ siRNA-NC group [(61.75±5.06)% and (13.48±2.16)%, respectively, P<0.05] and siRNA-ENO1 groups [(68.86±5.12)% and (18.12±2.25)%, respectively, P<0.05]. Cell invasion number in paclitaxel+ siRNA-ENO1 group (23.64±2.12) was lower than that in siRNA-ENO1 group and paclitaxel+ siRNA-NC group (42.16±2.75 and 37.35±2.42, respectively, P<0.05). The apoptosis rates of paclitaxel+ siRNA-NC group and siRNA-ENO1 group [(17.49±1.35)% and (15.29±1.50)%, respectively] were higher than that of siRNA-NC group [(7.21±0.70)%, P<0.05]. The apoptosis rate in the paclitaxel+ siRNA-ENO1 group [(24.59±2.40)%] was higher than those in the paclitaxel+ siRNA-NC group and siRNA-ENO1 group [(17.49±1.35)% and (15.29±1.50)%, respectively, P<0.05]. The expression levels of ENO1, PI3K/Akt signaling pathway related proteins including p-PI3K and p-Akt and the expression levels of PCNA, MMP-9 and Bcl-2 in siRNA-ENO1 group and paclitaxel+ siRNA-NC group were lower than those in siRNA-NC group (P<0.05). The expression levels of ENO1, p-PI3K, p-Akt, PCNA, MMP-9 and Bcl-2 in paclitaxel+ siRNA-ENO1 group were lower than those in siRNA-ENO1 group or paclitaxel+ siRNA-NC group (P<0.05). Conclusion: siRNA targeting inhibition of ENO1 expression can enhance the inhibitory effect of paclitaxel on proliferation, invasion and apoptosis of SK-HEP-1 cells, and its mechanism may be related to the inhibition of PI3K/AKT signaling pathway.

Interference in triiodothyronine (T3) analysis on the Immuno 1 Analyzer

OBJECTIVE

To evaluate the interference in Triiodothyronine (T3) analysis on the Immuno 1 Analyzer.

METHODS

We analyzed 686 samples for T3 using the Miles Technicon Immuno 1 Analyzer. We compared the results of 318 samples with those given by radioimmunoassay (RIA) and the remaining 368 results with those given by the Ciba-Corning ACS 180 analyzer.

RESULTS

On the Immuno 1 correlated with those by RIA or chemiluminescence immunoassay. However, results on eight patients by the Immuno 1 method were anomalously elevated. We attempted to find and eliminate the cause of the interference on the Immuno 1. Although the method uses an alkaline phosphatase labelled T3 analog and fluoresceinated monoclonal antibody, serum binding of fluorescein or alkaline phosphatase did not appear to be the major causes of the interference. Ethanol extraction of samples followed by reconstitution in zero calibrator was the only reliable way to eliminate the interference.

CONCLUSION

The Immuno 1 assay was more prone to interference than other methods. Until it is reformulated, we recommend that users assay ethanol extracts of samples with unexpectedly high T3.

The measurement of creatinine: a comparison between the Beckman Creatinine Analyzer II and the Selective Analyzer GSA IID

The measurement of creatinine by two Jaffé-based procedures is described. In comparing the Beckman Creatinine Analyzer II and the Greiner Selective Analyzer GSA IID, better between-day precision was observed with the former. Percentage recovery of creatinine added to serum was quantitative for the Beckman Creatinine Analyzer II and 92-95% for the Greiner Selective Analyzer. The Greiner Selective Analyzer employs a serum blank and for this reason interference produced by pseudo-Jaffé chromogens in the measurement of creatinine was far less significant than the corresponding interferences observed with the Beckman Creatinine Analyzer II. Comparison of results obtained on 100 sera and 40 urine samples provided correlation coefficients of 0.998 and 0.997 respectively.