Aldo-keto reductase family member C3(AKR1C3)promotes hepatocellular carcinoma cell growth by producing prostaglandin F2α

Hepatocellular carcinoma(HCC)is a leading cause of death worldwide.Current therapies are effective for HCC patients with early disease,but many patients suffer recurrence after surgery and have a poor response to chemotherapy.Therefore,new therapeutic targets are needed.We analyzed gene expression profiles between HCC tissues and normal adjacent tissues from public databases and found that the expression of genes involved in lipid metabolism was significantly different.The analysis showed that AKR1C3 was upregulated in tumors,and high AKR1C3 expression was associated with a poorer prognosis in HCC patients.In vitro,assays demonstrated that the knockdown of AKR1C3 or the addition of the AKR1C3 inhibitor indomethacin suppressed the growth and colony formation of HCC cell lines.Knockdown of AKR1C3 in Huh7 cells reduced tumor growth in vivo.To explore the mechanism,we performed pathway enrichment analysis,and the results linked the expression of AKR1C3 with prostaglandin F2 alpha(PGF2a)downstream target genes.Suppression of AKR1C3 activity reduced the production of PGF2a,and supplementation with PGF2a restored the growth of indomethacin-treated Huh7 cells.Knockdown of the PGF receptor(PTGFR)and treatment with a PTGFR inhibitor significantly reduced HCC growth.We showed that indomethacin potentiated the sensitivity of Huh7 cells to sorafenib.In summary,our results indicate that AKR1C3 upregulation may promote HCC growth by promoting the production of PGF2α,and suppression of PTGFR limited HCC growth.Therefore,targeting the AKR1C3-PGF2a-PTGFR axis may be a new strategy for the treatment of HCC.

Expression of prostaglandin E_2 receptors in rat hippocampus

BACKGROUND: Prostaglandin E2 (PGE2) can directly regulate toxic injury of hippocampal neurons through participation by its receptor. Increase of excitability of hippocampal membrane and long-term synaptic elasticity are closely related to PGE2, PGD2 and PGF2A. This suggests that PGE2 may be a key molecule of neuronal signal passage and regulate the existence of neurons through its receptor. However, which isoforms of PGE2 receptor expressing in hippocampal neurons is still unclear. OBJECTIVE: To research the subtype expression of PGE2 receptor in hippocampus of rats through mRNA transcription and protein interpretation. DESIGN: Animal studies with random, control and operator and designer double-blind methods. SETTING: University of South Carolina, Animal Center. MATERIALS: Sprague-Dawley rats, aged 12 weeks, weighing 200 g, females 48 and males 48, were selected from Animal Center in South Carolina University. Tri ReagentTM kit was provided by Molecular Research Center, USA. METHODS: The experiment was carried out in Animal Center in South Carolina University from January to December 2005. The expression of the PGE2 receptors was profiled and compared in rat hippocampus using real-time RT-PCR and Western-blot techniques. MAIN OUTCOME MEASURES: Expression of PGE2 receptors in various isoforms of hippocampal neurons of rats. RESULTS: mRNAs of all four EP1-4 subtypes were detected in the hippocampus. Western-blot data showed consistently detectable bands at approximately Mr 50 000 of EP1, Mr 40 000 and Mr 52 000 of EP2, Mr 45 000, Mr 57 000 and Mr 105 000 of EP3, and Mr 46 000 of EP4. CONCLUSION: Identifying four subtypes of EPs heterogeneously expresses in the hippocampus.

Lonicera japonica-induced inhibition of interleukin-1 beta thermogenesis and E-type prostaglandin receptor-3 expression in the preoptic area of rabbits

BACKGROUND： It has been shown that interleukin-1β（IL-1β） can induce fever by activating vascular endothelial cells and macrophages of the supraoptic crest to generate prostaglandin E2, which binds with receptors of the thermo-sensitive hypothalamic neurons. Lonicera japonica is one of the medicinal plants used widely in Asia for its antipyretic properties. However, these mechanisms have not yet been intensively studied. OBJECTIVE： To investigate the antipyretic effect and mechanisms of Lonicera japonica on IL-1β- induced febrile New Zealand rabbits by observing expression changes of E-type prostaglandin receptor-3 （EP3） mRNA in the preoptic anterior hypothalamus （POAH）. DESIGN： A randomized controlled study. SETTING： Electrophysiological Laboratory at the Department of Pathophysiology, Medical College of Jinan University; Department of Orthopaedics, First Hospital Affiliated to Medical College of Jinan University. MATERIALS： The experiment was performed from April to December 2005, using a total of 32 New Zealand white rabbits of both sexes, weighing 1.5 2.0 kg. All the animal experiments were performed according to the internationally accepted ethical guidelines. Lonicera japonica injection was purchased from Huanghe pharmaceutical factory of Xi＇an, China. IL-1βwas purchased from Sigma, USA. METHODS： A total of 32 rabbits were divided randomly into four groups： ① Normal saline （NS） control group;② Lonicerajaponica treatment group; ③ IL-1βtreatment group; and ④Lonicerajaponica plus IL-1βtreatment group. In the first 3 groups, the rabbits were given separate intravenous （i.v.） injections of l mL NS, l mL Lonicera japonica, and 100 ng IL-l β （dissolved in 0.9% NS without pyrogen）. In the Lonicerajaponica plus IL-1βgroup each rabbit was given i.v. injections of l mL NS and, 30 minutes later, 100 ng IL-1 β. MAIN OUTCOME MEASURES： Colonic temperature of each rabbit was measured at 0, 10, 20, 30, 40, 50, 60, and 70 minutes after injection and the maximum temperature rise （ A T） and the temperature response index after l hour （TRII） was calculated. Subsequently, in situ hybridization （ISH） was done with an ISH kit, EP3 mRNA expression in the POAH of all groups was measured （number of positive cells and average gray scale value）. RESULTS： A total of 32 rabbits were included in the result analysis, without any loss, （i） A T and TRII： there was no significant difference between the Lonicera japonica group and NS group （P 〉 0.05）. The IL-1β group was significantly greater compared to NS group （P 〈 0.01）. The Lonicera japonica plus IL-1β group was significantly less than the IL-1β group （P 〈 0.05）. ② In the NS and Lonicera japonica groups, the EP3 mRNA expression was negative （no coloration） or only weakly positive （only a few brown yellow particles in the cytoplasm cells could not be identified）. The number of positive cells and the average gray scale value were not significantly different between the two groups （P 〉 0.05）. In the IL-1β group, the number of positive cells was remarkably higher and the average gray scale value was lower than the NS group （P 〈 0.0 l）. In the Lonicera japonica plus IL-1β group, the number of positive cells was significantly less than the IL-1β group （P 〈 0.05）. However, the average gray scale value was greater than the IL-1β group （P 〈 0.05）. CONCLUSION： Lonicera japonica has obvious antipyretic effects on IL-1β-induced febrile rabbits and acts by inhibiting expression of EP3 mRNA in the POAH.

Targeted inhibition of GRK2 kinase domain by CP-25 to reverse fibroblast-like synoviocytes dysfunction and improve collagen-induced arthritis in rats

Rheumatoid arthritis(RA)is an autoimmune disease and is mainly characterized by abnormal proliferation of fibroblast-like synoviocytes(FLS).The up-regulated cellular membrane expression of G protein coupled receptor kinase 2(GRK2)of FLS plays a critical role in RA progression,the increase of GRK2 translocation activity promotes dysfunctional prostaglandin E4 receptor(EP4)signaling and FLS abnormal proliferation.Recently,although our group found that paeoniflorin-6’-O-benzene sulfonate(CP-25),a novel compound,could reverse FLS dysfunction via GRK2,little is known as to how GRK2 translocation activity is suppressed.Our findings revealed that GRK2 expression up-regulated and EP4 expression down-regulated in synovial tissues of RA patients and collagen-induced arthritis(CIA)rats,and prostaglandin E2(PGE2)level increased in arthritis.CP-25 could down-regulate GRK2 expression,up-regulate EP4 expression,and improve synovitis of CIA rats.CP-25 and GRK2 inhibitors(paroxetine or GSK180736 A)inhibited the abnormal proliferation of FLS in RA patients and CIA rats by down-regulating GRK2 translocation to EP4 receptor.The results of microscale thermophoresis(MST),cellular thermal shift assay,and inhibition of kinase activity assay indicated that CP-25 could directly target GRK2,increase the protein stability of GRK2 in cells,and inhibit GRK2 kinase activity.The docking of CP-25 and GRK2 suggested that the kinase domain of GRK2 might be an important active pocket for CP-25.G201,K220,K230,A321,and D335 in kinase domain of GRK2 might form hydrogen bonds with CP-25.Site-directed mutagenesis and co-immunoprecipitation assay further revealed that CP-25 down-regulated the interaction of GRK2 and EP4 via controlling the key amino acid residue of Ala321 of GRK2.Our data demonstrate that FLS proliferation is regulated by GRK2 translocation to EP4.Targeted inhibition of GRK2 kinase domain by CP-25 improves FLS function and represents an innovative drug for the treatment of RA by targeting GRK2.