Effects of RNA Targeting mPGES-1 on Proliferation and Apoptosis of K562/A Cells / 中山大学学报(医学科学版)

@#【Objective】 To explore the effects and the possible mechanism of RNA targeting membrane-bound prostaglandin E2 synthase l（mPGES- 1）on proliferation，apoptosis and drug resistance of leukemia cell line K562/A.【Methods】RNA interference was used to inhibit the expression of mPGES-1 of K562/A cells. Four groups were set up as follows：untreated group（K562/A），negative control group after interference（K562/A-NC），group after interference（K562/ A-KD），and group after interference with exogenous PGE2（K562/A-KD+PGE2）.Cell viability was assessed by CCK-8 assay. Cell apoptosis was analyzed by flow cytometry. Concentration of PGE2 was detected by ELISA. Proteins expression was detected by western blot.【Results】The expression of mPGES- 1 in K562/A cells was significantly down- regulated and the synthesis of PGE2 decreased（P < 0.000 1）after RNA interference. After RNA interference，the proliferation of K562/A cells was inhibited and apoptosis increased，and the sensitivity to chemotherapy drugs was enhanced（P < 0.05）. Meanwhile，the expression of β-catenin and MDR1 was decreased（P < 0.01）. Exogenous PGE2 could reverse the effect of RNA interference on proliferation ，apoptosis and drug sensitivity in K562/A cells（P < 0.05），and up-regulate the expression of β-catenin and MDR1（P < 0.01）. XAV939，an inhibitor of β-catenin，could down-regulate the expression of β- catenin and MDR1 in an dose- dependent pattern in K562/A cells（P < 0.05）.【Conclusions】RNA interference of mPGES- 1 could inhibit proliferation，induce apoptosis and reverse drug resistance in K562/A cells. The mechanism was related to reducing the synthesis of PGE2 and thus down- regulating the expression of β- catenin and MDR1. Wnt/β- catenin signal pathway may participate in the regulation of MDR1 by mPGES-1/PGE2.

Experimental study of the inhibitory effect of capsaicin on PGE2 concentration of IL-1βinduced NCI-H460 cells by downregulating COX-2 and mPGES-1 / 西安交通大学学报(医学版)

Objective To observe the effects of capsaicin on PGE2 concentration of IL-1β-induced human large cell carcinoma NCI-H460 cells,and further observe its effect on COX-2 and mPGES-1 so as to explore the possible mechanisms against non-small cell lung cancer.Methods NCI-H460 cells were cultured in vitro ;the effect of capsaicin in inhibiting NCI-H460 cells proliferation was observed.The 50% inhibitory concentration (IC50 ) was measured by MTT assay.IL-1βstimulation method was used to construct inflammation model,and the effects of capsaicin on COX-2 activity and PGE2 concentration in NCI-H460 cells were measured by ELISA.The effects of capsaicin on COX-2 and mPGES-1 protein level in NCI-H460 cells were analyzed by Western blot;the effects of capsaicin on COX-2 mRNA and mPGES-1 mRNA expressions in NCI-H460 cells were analyzed by Real-time PCR. Results MTT assay results showed that the growth of NCI-H460 cells treated with capsaicin was significantly inhibited compared with the control group (P <0.05 or P <0.01 ).Capsaicin could significantly decrease COX-2 activity and PGE2 concentration in NCI-H460 cells,and significantly decrease COX-2,mPGES-1 protein levels as well as COX-2,mPGES-1 mRNA expressions in NCI-H460 cells in a dose-dependent manner compared with the control group (P < 0.05 ).Conclusion Capsaicin inhibits the release of PGE2 by downregulating COX-2 and mPGES-1 mRNA expressions in NCI-H460 cells,which may be one mechanism of its effect against non-small cell lung cancer.

Impacts of Cytosolic Phospholipase A2, 15-Prostaglandin Dehydrogenase, and Cyclooxygenase-2 Expressions on Tumor Progression in Colorectal Cancer

PURPOSE: In addition to cyclooxygenase-2 (COX-2) which is related to prostaglandin E2 synthesis, other enzymes such as cytosolic phospholipase A2 (cPLA2), microsomal prostaglandin E2 synthase-1 (mPGES-1), and 15-prostaglandin dehydrogenase (15-PGDH) have been suggested to be related to carcinogenesis of colorectal cancer (CRC). The aim of this study was to investigate the roles of cPLA2, COX-2, mPGES-1, and 15-PGDH in tumor progression. MATERIALS AND METHODS: cPLA2, COX-2, mPGES-1, 15-PGDH, and vascular endothelial growth factor (VEGF) expressions were immunohistochemically examined in 89 CRC, and their expressions were compared with each other or clinicopathologic parameters as well as VEGF as tumor progression parameters. RESULTS: cPLA2 was expressed in 54.5%, COX-2 in 80.5%, mPGES-1 in 96.4%, 15-PGDH in 46.1%, and VEGF in 65.9%. The expression of cPLA2 correlated with VEGF expression. COX-2 expression was correlated with the depth of invasion, tumor stage, cPLA2, and VEGF expressions. Moreover, VEGF revealed the highest expression in the tissues positive for both cPLA2 and COX-2. Furthermore, 15-PGDH expression was inversely correlated with VEGF expression. CONCLUSION: The present study demonstrates that cPLA2 and mPGES-1, in addition to COX-2, are constitutively overexpressed, and that 15-PGDH might be attenuated in colorectal cancer. Furthermore, cPLA2 and 15-PGDH as well as COX-2 could have an important role in tumor progression.

Expression of Cyclooxygenase-2 and Microsomal Prostaglandin E2 Synthase-1 in Human Renal Cell Carcinoma / 대한비뇨기과학회지

PURPOSE: There is ample evidence suggesting an important role for cyclooxygenase-2 (COX-2) and microsomal prostaglandin E2 synthase-1 (mPGES-1) in tumorigenesis. This study aimed at evaluating the clinical significance of the expressions of COX-2 and mPGES-1 in the development and progression of human renal cell carcinomas (RCC). MATERIALS AND METHODS: Tumor samples were obtained from 27 RCC patients who had undergone a radical nephrectomy. The expressions of COX-2 and mPGES-1 were evaluated using immunohistochemistry and Western blot analyses. RESULTS: COX-2 and mPGES-1 were expressed in 16 (59.3%) and in 11 (40.7%) of the 27 RCC patients. The expressions of COX-2 and mPGES-1 were correlated with the tumor grade, but not with the pathological stage. Western blot analysis confirmed a higher COX-2 expression in the RCC than non-tumorous tissues, but that of mPGES-1 was similar between the tumorous and non-tumorous portions. CONCLUSIONS: Our results suggest that the expression of COX-2 in RCC patients may be associated with carcinogenesis and; therefore, a useful biomarker in RCC.