Haplotype of prostaglandin synthase 2/cyclooxygenase 2 is involved in the susceptibility to inflammatory bowel disease

AIM： Prostaglandin G/H synthase 2 （PTGS2 or COX2） is one of the key factors in the cellular response to inflammation. PTGS2 is expressed in the affected intestinal segments of patients with inflammatory bowel diseases （IBD）. In IBD patients, non-steroidal anti-inflammatory drugs, which have been shown to reduce both the production and activity of PTGS2, may activate IBD and aggravate the symptoms. We aimed at examining genetic variants of PTGS2 that may be risk factors for IBD. METHODS： We genotyped 291 individuals diagnosed with IBD and 367 controls from the Dutch population for the five most frequent polymorphisms of the PTG52 gene. Clinical data were collected on all patients. DNA was extracted via normal laboratory methods. Genotyping was carried out using multiplex PCR followed by the Invader Assay and the 5＇ exonuclease assay （TaqMan）. New polymorphism screening was performed by pre-screening with denaturing high-performance liquid chromatography, followed by fluorescent sequencing. RESULTS： Allele 5209G was weakly associated with Crohn＇s disease （odds ratio [OR] 1.63, 95% confidence interval [CI] 1.03-2.57）, and allele 8473T with ulcerativecolitis （OR 1.50, 95%CI 1.00-2.27）. The haplotype including both alleles showed a strong association with IBD （OR 13.15, 95%CI 3.17-116.15）. This haplotype, while rare （-0.3%） in the general population, is found more frequently in patients （3.5%）. CONCLUSION： Our data suggest that this haplotype of PTGS2 contributes to the susceptibility of IBD.

Prostaglandin F_(2α)synthase promotes oxaliplatin resistance in colorectal cancer through prostaglandin F_(2α)-dependent and F_(2α)-independent mechanism

BACKGROUND Oxaliplatin(Oxa)is the first-line chemotherapy drug for colorectal cancer(CRC),and Oxa resistance is crucial for treatment failure.Prostaglandin F_(2α)synthase(PGF 2α)(PGFS),an enzyme that catalyzes the production of PGF_(2α),is involved in the proliferation and growth of a variety of tumors.However,the role of PGFS in Oxa resistance in CRC remains unclear.AIM To explore the role and related mechanisms of PGFS in mediating Oxa resistance in CRC.METHODS The PGFS expression level was examined in 37 pairs of CRC tissues and paracancerous tissues at both the mRNA and protein levels.Overexpression or knockdown of PGFS was performed in CRC cell lines with acquired Oxa resistance(HCT116-OxR and HCT8-OxR)and their parental cell lines(HCT116 and HCT8)to assess its influence on cell proliferation,chemoresistance,apoptosis,and DNA damage.For determination of the underlying mechanisms,CRC cells were examined for platinum-DNA adducts and reactive oxygen species(ROS)levels in the presence of a PGFS inhibitor or its products.RESULTS Both the protein and mRNA levels of PGFS were increased in the 37 examined CRC tissues compared to the adjacent normal tissues.Oxa induced PGFS expression in the parental HCT116 and HCT8 cells in a dosedependent manner.Furthermore,overexpression of PGFS in parental CRC cells significantly attenuated Oxainduced proliferative suppression,apoptosis,and DNA damage.In contrast,knockdown of PGFS in Oxa-resistant HCT116 and HCT8 cells(HCT116-OxR and HCT8-OxR)accentuated the effect of Oxa treatment in vitro and in vivo.The addition of the PGFS inhibitor indomethacin enhanced the cytotoxicity caused by Oxa.Treatment with the PGFS-catalyzed product PGF_(2α)reversed the effect of PGFS knockdown on Oxa sensitivity.Interestingly,PGFS inhibited the formation of platinum-DNA adducts in a PGF_(2α)-independent manner.PGF_(2α)exerts its protective effect against DNA damage by reducing ROS levels.CONCLUSION PGFS promotes resistance to Oxa in CRC via both PGF_(2α)-dependent and PGF_(2α)-independent mechanisms.

Acetylsalicylic acid interferes with embryonic kidney growth and development by a prostaglandin-independent mechanism

AIM To evaluate the effects of the non-selective, non-steroidal anti-infammatory drug （NSAID） acetylsalicylic acid （ASA）, on ex vivo embryonic kidney growth and development.METHODS Pairs of fetal mouse kidneys at embryonic day 12.5 were cultured ex vivo in increasing concentrations of ASA （0.04-0.4 mg/mL） for up to 7 d. One organ from each pair was grown in control media and was used as the internal control for the experimental contralateral organ. In some experiments, organs were treated with ASA for 48 h and then transferred either to control media alone or control media containing 10 μmol/L prostaglandin E2 （PGE2） for a further 5 d. Fetal kidneys were additionally obtained from prostaglandin synthase 2 homozygous null or heterozygous （PTGS2-/- and PTGS2-/＋） embryos and grown in culture. Kidney cross-sectional area was used to determine treatment effects on kidney growth. Whole-mount labelling to fluorescently detect laminin enabled crude determination of epithelial branching using confocal microscopy.RESULTSIncreasing ASA concentration （0.1, 0.2 and 0.4 mg/mL） significantly inhibited metanephric growth （P 〈 0.05）. After 7 d of culture, exposure to 0.2 mg/mL and 0.4 mg/mL reduced organ size to 53% and 23% of control organ size respectively （ P 〈 0.01）. Addition of 10 μmol/L PGE2 to culture media after exposure to 0.2 mg/mL ASA for 48 h resulted in a return of growth area to control levels. Application of control media alone after cessation of ASA exposure showed no benefit on kidney growth. Despite the apparent recovery of growth area with 10 μmol/L PGE2, no obvious renal tubular structures were formed. The number of epithelial tips generated after 48 h exposure to ASA was reduced by 40% （0.2 mg/mL; P 〈 0.05） and 47% （0.4 mg/mL; P 〈 0.01）. Finally, growth of PTGS2-/- and PTGS2＋/- kidneys in organ culture showed no differences, indicating that PTGS2 derived PGE2 may at best have a minor role.CONCLUSIONASA reduces early renal growth and development but the role of prostaglandins in this may be minor.

Prognostic analysis of prostaglandin D2 synthase in diffuse large B‑cell lymphoma

Purpose We aimed to analyse the correlation between prostaglandin D2 synthase(PTGDS)and a diffuse large B-cell lymphoma(DLBCL)prognosis.Methods We retrospectively collected two hundred paraffin-embedded tissue specimens that were pathologically diagnosed as DLBCL in the Fujian Tumour Hospital between January 2014 and December 2018.An abundance of paraffin-embedded tumour tissues were obtained.Twenty patients with lymphocyte-rich,benign,tissue-reactive,hypertrophic tonsillitis were selected as controls.Wax blocks were selected for primary cases and the controls were screened by professional pathologists.The levels of prostaglandin D2 synthase(PTGDS)and the EMT-related molecules,E-cadherin and vimentin,were detected by immunohistochemistry in clinical samples.A chi-square test revealed the correlations between PTGDS expression and clinicopathological characteristics,including age,sex,primary site,clinical stage,immunotyping,and International Prognostic Index(IPI)score.The Kaplan–Meier survival analysis was performed,and the diagnostic value was evaluated by receiver operating characteristic(ROC)curve analysis.Results A total of 138 cases(69%)were found to be PTGDS positive(>30%positive cells).PTGDS staining was negative(<30%positive cells)in 62 cases(31%).We collected the corresponding clinicopathological information and found that PTGDS expression was not significantly related to the patients’age,tumour stage,presence of extranodal invasion,or IPI score.According to the follow-up data,patients with low PTGDS expression had poor progression-free survival(PFS)and overall survival(OS),with 2-year PFS and OS rates of 41.7%and 50%,respectively.The 2-year PFS and OS rates of PTGDS-positive patients were 89.3%and 92.9%,respectively(P<0.0001),and the differences were significant.Conclusion We found that the expression level of PTGDS is significantly correlated with the prognosis of diffuse large B-cell lymphoma.

Amentoflavone protects hippocampal neurons: anti-inflammatory, antioxidative, and antiapoptotic effects

Amentoflavone is a natural biflavone compound with many biological properties, including anti-inflammatory, antioxidative, and neuroprotective effects. We presumed that amentoflavone exerts a neuroprotective effect in epilepsy models. Prior to model establishment, mice were intragastrically administered 25 mg/kg amentoflavone for 3 consecutive days. Amentoflavone effectively prevented pilocarpine-induced epilepsy in a mouse kindling model, suppressed nuclear factor-κB activation and expression, inhibited excessive discharge of hippocampal neurons resulting in a reduction in epileptic seizures, shortened attack time, and diminished loss and apoptosis of hippocampal neurons. Results suggested that amentoflavone protected hippocampal neurons in epilepsy mice via anti-inflammation, antioxidation, and antiapoptosis, and then effectively prevented the occurrence of seizures.