title: Ectopic NGAL expression can alter sensitivity of breast cancer cells to EGFR, Bcl-2, CaM-K inhibitors and the plant natural product berberine.
abstract: Neutrophil gelatinase-associated lipocalin (NGAL, a.k.a Lnc2) is a member of the lipocalin family and has diverse roles. NGAL can stabilize matrix metalloproteinase-9 from autodegradation. NGAL is considered as a siderocalin that is important in the transport of iron. NGAL expression has also been associated with certain neoplasias and is implicated in the metastasis of breast cancer. In a previous study, we examined whether ectopic NGAL expression would alter the sensitivity of breast epithelial, breast and colorectal cancer cells to the effects of the chemotherapeutic drug doxorubicin. While abundant NGAL expression was detected in all the cells infected with a retrovirus encoding NGAL, this expression did not alter the sensitivity of these cells to doxorubicin as compared with empty vector-transduced cells. We were also interested in determining the effects of ectopic NGAL expression on the sensitivity to small-molecule inhibitors targeting key signaling molecules. Ectopic NGAL expression increased the sensitivity of MCF-7 breast cancer cells to EGFR, Bcl-2 and calmodulin kinase inhibitors as well as the natural plant product berberine. Furthermore, when suboptimal concentrations of certain inhibitors were combined with doxorubicin, a reduction in the doxorubicin IC 50 was frequently observed. An exception was observed when doxorubicin was combined with rapamycin, as doxorubicin suppressed the sensitivity of the NGAL-transduced MCF-7 cells to rapamycin when compared with the empty vector controls. In contrast, changes in the sensitivities of the NGAL-transduced HT-29 colorectal cancer cell line and the breast epithelial MCF-10A cell line were not detected compared with empty vector-transduced cells. Doxorubicin-resistant MCF-7/Dox (R)  cells were examined in these experiments as a control drug-resistant line; it displayed increased sensitivity to EGFR and Bcl-2 inhibitors compared with empty vector transduced MCF-7 cells. These results indicate that NGAL expression can alter the sensitivity of certain cancer cells to small-molecule inhibitors, suggesting that patients whose tumors exhibit elevated NGAL expression or have become drug-resistant may display altered responses to certain small-molecule inhibitors.
authors.affiliation: Department of Microbiology & Immunology, Brody School of Medicine, East Carolina University, Greenville, NC USA.
authors.forename: William H
authors.initials: WH
authors.lastname: Chappell
authors.forename: Stephen L
authors.initials: SL
authors.lastname: Abrams
authors.forename: Richard A
authors.initials: RA
authors.lastname: Franklin
authors.forename: Michelle M
authors.initials: MM
authors.lastname: LaHair
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Montalto
authors.forename: Melchiorre
authors.initials: M
authors.lastname: Cervello
authors.forename: Alberto M
authors.initials: AM
authors.lastname: Martelli
authors.forename: Ferdinando
authors.initials: F
authors.lastname: Nicoletti
authors.forename: Saverio
authors.initials: S
authors.lastname: Candido
authors.forename: Massimo
authors.initials: M
authors.lastname: Libra
authors.forename: Jerry
authors.initials: J
authors.lastname: Polesel
authors.forename: Renato
authors.initials: R
authors.lastname: Talamini
authors.forename: Michele
authors.initials: M
authors.lastname: Milella
authors.forename: Agostino
authors.initials: A
authors.lastname: Tafuri
authors.forename: Linda S
authors.initials: LS
authors.lastname: Steelman
authors.forename: James A
authors.initials: JA
authors.lastname: McCubrey
mesh_terms: D000209:Acute-Phase Proteins / Q000235:genetics / Q000378:metabolism*; D000903:Antibiotics, Antineoplastic / Q000494:pharmacology; D001596:Benzylamines / Q000494:pharmacology; D001599:Berberine / Q000494:pharmacology*; D001713:Biphenyl Compounds / Q000494:pharmacology; D001943:Breast Neoplasms / Q000378:metabolism / Q000473:pathology; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000037:antagonists & inhibitors* / Q000378:metabolism; D045744:Cell Line, Tumor; D004317:Doxorubicin / Q000494:pharmacology; D019008:Drug Resistance, Neoplasm / Q000187:drug effects; D066246:ErbB Receptors / Q000037:antagonists & inhibitors* / Q000378:metabolism; D005260:Female; D015870:Gene Expression / Q000187:drug effects; D019073:HT29 Cells; D006801:Humans; D000071068:Lipocalin-2; D054834:Lipocalins / Q000235:genetics / Q000378:metabolism*; D061986:MCF-7 Cells; D009596:Nitrophenols / Q000494:pharmacology; D010879:Piperazines / Q000494:pharmacology; D047428:Protein Kinase Inhibitors / Q000494:pharmacology*; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000378:metabolism*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000037:antagonists & inhibitors* / Q000378:metabolism; D011799:Quinazolines / Q000494:pharmacology; D020123:Sirolimus / Q000494:pharmacology; D013449:Sulfonamides / Q000494:pharmacology; D020032:Tyrphostins / Q000494:pharmacology; D000096926:Benzenesulfonamides
chemical_list: D000209:Acute-Phase Proteins; D000903:Antibiotics, Antineoplastic; D001596:Benzylamines; D001599:Berberine; D001713:Biphenyl Compounds; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D004317:Doxorubicin; D066246:ErbB Receptors; D000071068:Lipocalin-2; D054834:Lipocalins; D009596:Nitrophenols; D010879:Piperazines; D047428:Protein Kinase Inhibitors; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D011799:Quinazolines; D020123:Sirolimus; D013449:Sulfonamides; D020032:Tyrphostins; C501332:ABT-737; C489506:LCN2 protein, human; C072105:KN 93; D000096926:Benzenesulfonamides; C101044:RTKI cpd