Accurate quantification of PGE2 in the polyposis in rat colon (Pirc) model by surrogate analyte-based UPLC–MS/MS

Cui, Yun; Dashwood, Wan‐Mohaiza; Kwong, Lawrence N.; Gao, Song; Yin, Tongming; Ling, Qinglan; Singh, Rashim; Dashwood, Roderick H.; Hu, Ming

doi:10.1016/j.jpba.2017.07.025

Cited by 10 publications

(4 citation statements)

References 51 publications

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“…The average RF value was 0.88 (see Equation ), which did not equal 1. Possible reasons for the response difference included ionization difference, gas‐phase hydrogen/deuterium scrambling, inaccurate purity characterization, kinetic isotope effect, and stable‐isotope‐labeled analyte distribution . Therefore, we calculated the concentration of acetic acid using the RF value and the calibration curve of the surrogate analyte (see Equations and for details).…”

Section: Resultsmentioning

confidence: 99%

A rapid and convenient derivatization method for quantitation of short‐chain fatty acids in human feces by ultra‐performance liquid chromatography/tandem mass spectrometry

Zhang

Huang

et al. 2020

Rapid Comm Mass Spectrometry

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Rationale: Short-chain fatty acids (SCFAs) are associated with intestinal microbiota and diseases in humans. SCFAs have a low response in mass spectrometry, and in order to increase sensitivity, reduce sample consumption, shorten analysis time, and simplify sample preparation steps, a derivatization method was developed. Methods:We converted seven SCFAs into amide derivatives with 4-aminomethylquinoline. The reaction occurred for 20 min at room temperature. The analytes were separated on a reversed-phase C18 column and quantitated in the positive ion electrospray ionization mode using multiple reaction monitoring. Acetic acid-d 4 was used as the stable-isotope-labeled surrogate analyte for acetic acid in the working solutions, while the other stable-isotope-labeled standards were used as internal standards (ISs). Results:Method validation showed that the intra-day and inter-day precision of quantitation for the seven SCFAs over the whole concentration range was ≤3.8% (n = 6). The quantitation accuracy ranged from 85.5% to 104.3% (n = 6). Most important, the collected feces were vortexed immediately with ethanol. Conclusions:This study provides a new derivatization method for a precise, accurate, and rapid quantitation of SCFAs in human feces using ultra-performance liquid chromatography/tandem mass spectrometry. This method successfully determined the concentration of SCFAs in human feces and could assist in the exploration of intestinal microbiota and diseases.

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Section: Resultsmentioning

confidence: 99%

A rapid and convenient derivatization method for quantitation of short‐chain fatty acids in human feces by ultra‐performance liquid chromatography/tandem mass spectrometry

Zhang

Huang

et al. 2020

Rapid Comm Mass Spectrometry

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“…The PGE 2 was quantitated using the validated method published by us previously with modification. 18 Briefly, a 50 μL aliquot of cell medium and 10 µL d4-PGE 2 (as the internal standard, final concentration was 20ng/mL) were mixed with 500 μL of ethyl acetate for liquid–liquid extraction. Then, 400 µL supernatant was transferred from the mixture after vortex and centrifugation.…”

Section: Methodsmentioning

confidence: 99%

“…15,16 Several studies also found that celecoxib treatment significantly reduced the tumor multiplicity in the colon in Pirc rats (Pirc, F344/NTac-Apc am1137 ), which has similar biology that closely models human FAP characteristics. 17,18 However, it has been proven in humans that systemic inhibition of COX-2 for a prolonged period of time caused significant and sometimes deadly adverse effects because COX-2 is constructively expressed in some tissues including the cardiovascular system. 19,20 Evidence in support of COX-1 being "good" for our health is that PGE 2 derived from COX-1 is mainly involved in homeostatic functions throughout the body.…”

mentioning

confidence: 99%

Comparison of Absolute Expression and Turnover Number of COX-1 and COX-2 in Human and Rodent Cells and Tissues

Li¹,

Sun²,

Zenga³

et al. 2022

JIR

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Objective We aim to quantify the absolute protein expression of cyclooxygenase-1 (COX-1) and cyclooxygenase-2 (COX-2) in various cells and tissues to determine the relative contribution of COX-1 and COX-2 to PGE 2 production. Methods An LC-MS method was developed and validated, then used for quantifying the absolute amounts of COX-1 and COX-2 in recombinant human COX-1 and COX-2, lysates from different cells, tissue microsomes of rodents and humans, Pirc rat colonic polyps, and biopsy specimens from squamous cell carcinoma (SCC) patients. The COX-1 and COX-2 turnover numbers were subsequently calculated based on apparent formation rates of PGE 2 . Results A robust LC-MS method for quantification of COX-1 and COX-2 was developed and validated and then used to calculate their apparent turnover numbers. The results showed that COX-1 expression levels were much higher than that of COX-2 in all the tested tissues including the colonic epithelium of F344 (28-fold) and Pirc rats (20-fold), colonic polyps of Pirc rats (8-fold), and biopsy specimens of SCC patients (11–17-fold). In addition, both COX-1 and COX-2 were higher in polyps when compared to adjacent mucosa of Pirc rats. The turnover number of recombinant human COX-2 was 14-fold higher than that of recombinant human COX-1. LPS stimulation increased COX-2 protein expression in three cell lines (Raw 264.7, SCC9 and EOMA) as expected but unexpectedly increased COX-1 protein expression (13.8-fold) in EOMA cells. Conclusion In human oral cancer tissues and cells as well as Pirc rat colon, COX-1 plays an unexpectedly but more important role than COX-2 in abnormal PGE 2 production since COX-1 expression is much higher than COX-2. In addition, COX-1 expression levels are inducible in cells, and higher in polyps than surrounding mucosa in Pirc rat colon. These results indicate that targeted suppression of local COX-1 should be considered to reduce colon-specific PGE 2 -mediated inflammation.

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“…We have previously studied the epigenetic mechanism of action of 3,3′- Diindolylmethane (DIM) in colon cancer [ 10 ]. DIM is a natural chemopreventive compound that is formed from indol-3-cabinol (I3C) and has been reported to have various anti-cancer mechanisms in CRC [ 11 , 12 , 13 , 14 , 15 , 16 ]. DIM can be found in cruciferous vegetables such as broccoli, Brussels sprouts, cabbage and kale.…”

Section: Introductionmentioning

confidence: 99%

Chemopreventive Agent 3,3′-Diindolylmethane Inhibits MDM2 in Colorectal Cancer Cells

Gao

Liu

Kedika

et al. 2020

IJMS

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3,3′-Diindolylmethane (DIM) is a naturally derived chemopreventive compound. It comes from glucobrassicin, an indole glucosinolate enriched in cruciferous vegetables, and is formed in the acidic environment of the stomach after ingestion. Mouse double minute 2 homolog (MDM2) is an important, multi-functional oncogenic protein and it has been well recognized for its negative regulation of the tumor suppressor protein p53. We discovered a novel mechanism of action of DIM, that it directly inhibits MDM2 in multiple colorectal cancer (CRC) cell lines. Treatment with DIM decreased MDM2 at messenger RNA (mRNA) and protein levels, inhibited cancer cell proliferation, and induced cell cycle arrest and apoptosis. DIM-induced decrease of MDM2 is p53-independent and is partly mediated by proteasome degradation of MDM2, as blocking of the proteasome activity reversed MDM2 protein inhibition. Overexpression of MDM2 blocked DIM’s effects in growth suppression and apoptosis induction. When combined with imidazoline MDM2 inhibitors (Nutlin-3a and Idasanutlin/RG-7388), synergism was observed in cancer cell growth inhibition. In summary, our data support a new mechanism of action for DIM in direct inhibition of MDM2. The identification of MDM2 as a novel DIM target may help develop a new strategy in CRC prevention.

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Accurate quantification of PGE2 in the polyposis in rat colon (Pirc) model by surrogate analyte-based UPLC–MS/MS

Cited by 10 publications

References 51 publications

A rapid and convenient derivatization method for quantitation of short‐chain fatty acids in human feces by ultra‐performance liquid chromatography/tandem mass spectrometry

A rapid and convenient derivatization method for quantitation of short‐chain fatty acids in human feces by ultra‐performance liquid chromatography/tandem mass spectrometry

Comparison of Absolute Expression and Turnover Number of COX-1 and COX-2 in Human and Rodent Cells and Tissues

Chemopreventive Agent 3,3′-Diindolylmethane Inhibits MDM2 in Colorectal Cancer Cells

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