Impact of the Cyclooxygenase System on Doxorubicin-Induced Functional Multidrug Resistance 1 Overexpression and Doxorubicin Sensitivity in Acute Myeloid Leukemic HL-60 Cells

Abstract

Multidrug resistance (MDR), a challenge in treating childhood acute myeloid leukemia (AML), is frequently associated with decreased drug accumulation caused by multidrug transporter MDR1. Doxorubicin, an important anti-AML drug, is a known MDR1 substrate and inducer. Its cytostatic efficacy is thus limited by MDR1 overexpression. A recent study demonstrated cyclooxygenase-2-dependent, prostaglandin E 2 (PGE 2 )-mediated regulation of mdr1b expression in primary rat hepatocyte cultures. Cyclooxygenase-2 expression is increased in several malignancies and considered a negative prognostic factor. Our study focused on cyclooxygenase system's impact on drug-induced MDR1 overexpression in AML cells. As a prerequisite, coexpression of MDR1 and cyclooxygenase-2 mRNA in HL-60 cells and primary AML blasts was demonstrated by Northern blot. Interestingly, incubation of AML cells with doxorubicin not only induced functionally active MDR1 overexpression but also mediated increased cyclooxygenase-2 mRNA and protein expressions with subsequent PGE 2 release (determined by flow cytometry, rhodamine123 efflux assay, reverse transcription-polymerase chain reaction, and enzyme-linked immunosorbent assay). After preincubation and subsequent parallel treatment with the cyclooxygenase-2-preferential inhibitor meloxicam, doxorubicin-induced MDR1 overexpression and function were reduced (maximally at 0.1-0.5 M meloxicam), whereas cytostatic efficacy of doxorubicin in 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide assays was significantly increased by up to 78 (HL-60) and 30% (AML blasts) after 72 h of doxorubicin treatment. In HL-60 cells, meloxicam-dependent effect on doxorubicin cytotoxicity was neutralized by PGE 2 preincubation. In conclusion, the cyclooxygenase system, especially the cyclooxygenase-2 isoform, might be involved in regulating doxorubicin-induced MDR1 overexpression in AML cells, with PGE 2 seeming to be a mediating factor. Cyclooxygenase inhibitors thus bear promise to overcome MDR in AML and improve therapy.

Enhancement of Doxorubicin Cytotoxicity on Human Esophageal Squamous Cell Carcinoma Cells by Indomethacin and 4-[5-(4-Chlorophenyl)-3-(trifluoromethyl)-1H-pyrazol-1-yl]benzenesulfonamide (SC236) via Inhibiting P-Glycoprotein Activity

“…A growing body of evidence has demonstrated that NSAIDs and COX-2-selective inhibitors enhance the cytotoxic action of certain chemotherapeutic drugs in a variety of cancer cells (Draper et al, 1997;Duffy et al, 1998;Roller et al, 1999;Awara et al, 2004;O'Connor et al, 2004;Puhlmann et al, 2005;Zatelli et al, 2005Zatelli et al, , 2007Zrieki et al, 2008). In agreement with these findings, our results show that the NSAID indomethacin and the COX-2-selective inhibitor SC236 sensitize human esophageal squamous cell carcinoma cells (HKESC-1 and HKESC-2) to the cytotoxic action of doxorubicin.…”

“…The basal PGE 2 level released by HKESC-1 cells was 332 pg/ml, or approximately 10 Ϫ3 M (data not shown). Moreover, it has been reported that PGE 2 at the concentration of 3 g/ml (8.5 M) neutralized the enhancing effect of the COX-2 selective inhibitor meloxicam on the cytotoxic action of doxorubicin in acute myeloid leukemia HL-60 cells (Puhlmann et al, 2005). Therefore, PGE 2 at concentrations ranging from 10 Ϫ3 to 10 M were used in our study.…”

“…Among these ATP-binding cassette transporters, P-gp and MRP1 are two major transporters that function as pumps to extrude doxorubicin from cancer cells (Gillet et al, 2007;Mimeault et al, 2008). It has been suggested that COX inhibitors may sensitize cancer cells to chemotherapeutic drugs like doxorubicin via inhibiting P-gp (Awara et al, 2004;Puhlmann et al, 2005;Zatelli et al, 2005Zatelli et al, , 2007Zrieki et al, 2008) or MRP1 (Draper et al, 1997;Duffy et al, 1998;Roller et al, 1999;O'Connor et al, 2004). Although COX inhibitors like indomethacin has been reported to reverse MRP-mediated efflux of doxorubicin via inhibition of MRP1 pumping system (Draper et al, 1997;Duffy et al, 1998;Roller et al, 1999), the involvement of MRP1 in augmentation of doxorubicin toxicity by indomethacin or SC236 is excluded in our study based on the findings that MRP1 protein is undetectable in HKESC-1 and HKESC-2 cells (data not shown).…”

“…COX inhibitors also enhance the action of cytostatic drugs. In this regard, it has been suggested that COX inhibitors overcome the MDR of tumors to chemotherapeutic drugs like doxorubicin by inhibiting P-gp in some human cancers such as breast cancer, colorectal cancer, medullary thyroid carcinoma, and acute myeloid leukemic cells (Awara et al, 2004;Puhlmann et al, 2005;Zatelli et al, 2005;Zatelli et al, 2007;Zrieki et al, 2008). However, their action on esophageal cancer has not been reported.…”

Phorbol Ester TPA Modulates Chemoresistance in the Drug Sensitive Breast Cancer Cell Line MCF-7 by Inducing Expression of Drug Efflux Transporter ABCG2

“…In recent years, it has been reported that COX-2 modulates ABC transporter expression and is involved in the development of the MDR phenotype. A correlation between expression of COX-2 and MDR1 was found in breast cancer (Ratnasinghe et al, 2001), hepatocellular carcinoma (Fantappiè & R, 2002 ), and acute myeloblastic lymphoma (Puhlmann et al, 2005). Previously, we demonstrated that induction of COX-2 expression could increase ABCG2 activity (mitoxantrone efflux) in breast cancer cell lines .…”