Inhibition of mPGES-1 or COX-2 Results in Different Proteomic and Lipidomic Profiles in A549 Lung Cancer Cells.

Filip Bergqvist,Helena Idborg,Joan Raouf,Kim Kultima,Craig E Wheelock,Per-Johan Jakobsson,Petter Englund,Marina Korotkova,Elena Ossipova,Karin Larsson,Karin Englund,Payam Emami Khoonsari,Antonio Checa

doi:10.3389/fphar.2019.00636

Abstract

Pharmacological inhibition of microsomal prostaglandin E synthase (mPGES)-1 for selective reduction in prostaglandin E2 (PGE2) biosynthesis is protective in experimental models of cancer and inflammation. Targeting mPGES-1 is envisioned as a safer alternative to traditional non-steroidal anti-inflammatory drugs (NSAIDs). Herein, we compared the effects of mPGES-1 inhibitor Compound III (CIII) with the cyclooxygenase (COX)-2 inhibitor NS-398 on protein and lipid profiles in interleukin (IL)-1β-induced A549 lung cancer cells using mass spectrometry. Inhibition of mPGES-1 decreased PGE2 production and increased PGF2α and thromboxane B2 (TXB2) formation, while inhibition of COX-2 decreased the production of all three prostanoids. Our proteomics results revealed that CIII downregulated multiple canonical pathways including eIF2, eIF4/P70S6K, and mTOR signaling, compared to NS-398 that activated these pathways. Moreover, pathway analysis predicted that CIII increased cell death of cancer cells (Z = 3.8, p = 5.1E−41) while NS-398 decreased the same function (Z = −5.0, p = 6.5E−35). In our lipidomics analyses, we found alterations in nine phospholipids between the two inhibitors, with a stronger alteration in the lysophospholipid (LPC) profile with NS-398 compared to CIII. Inhibition of mPGES-1 increased the concentration of sphinganine and dihydroceramide (C16:0DhCer), while inhibition of COX-2 caused a general decrease in most ceramides, again suggesting different effects on cell death between the two inhibitors. We showed that CIII decreased proliferation and potentiated the cytotoxic effect of the cytostatic drugs cisplatin, etoposide, and vincristine when investigated in a live cell imaging system. Our results demonstrate differences in protein and lipid profiles after inhibition of mPGES-1 or COX-2 with important implications on the therapeutic potential of mPGES-1 inhibitors as adjuvant treatment in cancer. We encourage further investigations to illuminate the clinical benefit of mPGES-1 inhibitors in cancer.

Highlights

Prostaglandin E2 (PGE2) is a key regulatory lipid mediator in inflammation, immune responses, and tumor development (Wang and Dubois, 2010; Ricciotti and FitzGerald, 2011; Kalinski, 2012; Nakanishi and Rosenberg, 2013). It is a metabolite of arachidonic acid, which is released from membrane phospholipids by cytosolic phospholipase A2 and converted by cyclooxygenase (COX)-1/2 into unstable PGH2 that is further processed by terminal synthases into the major prostanoids including PGE2, PGD2, PGF2α, PGI2, and thromboxane A2 (TXA2) (Smith et al, 2011)
Reducing PGE2 concentration in the tumor microenvironment by selective inhibition of microsomal prostaglandin E synthase (mPGES)-1 is anticipated as an alternative strategy for anti-cancer treatment with improved selectivity and safety compared to conventional non-steroidal anti-inflammatory drugs (NSAIDs) (Larsson and Jakobsson, 2015)
Selective microsomal prostaglandin E synthase-1 (mPGES-1) inhibitor Compound III (CIII) concentration-dependently reduces PGE2 production (Leclerc et al, 2013). This effect is in contrast to treatment with the selective COX-2 inhibitor NS-398, which inhibits the production of all prostanoids

Summary

Introduction

Prostaglandin E2 (PGE2) is a key regulatory lipid mediator in inflammation, immune responses, and tumor development (Wang and Dubois, 2010; Ricciotti and FitzGerald, 2011; Kalinski, 2012; Nakanishi and Rosenberg, 2013). It is a metabolite of arachidonic acid, which is released from membrane phospholipids by cytosolic phospholipase A2 (cPLA2) and converted by cyclooxygenase (COX)-1/2 into unstable PGH2 that is further processed by terminal synthases into the major prostanoids including PGE2, PGD2, PGF2α, PGI2, and thromboxane A2 (TXA2) (Smith et al, 2011). Genetic deletion as well as pharmacological inhibition of mPGES-1 have demonstrated this target as an effective anti-cancer regimen (Hanaka et al, 2009; Kamei et al, 2009; Nakanishi et al, 2011; Sasaki et al, 2012; Howe et al, 2013; Takahashi et al, 2014; Zelenay et al, 2015; Kock et al, 2018)

Objectives

Methods

Results

Conclusion