title: Resistance to diverse apoptotic triggers in multidrug resistant HL60 cells and its possible relationship to the expression of P-glycoprotein, Fas and of the novel anti-apoptosis factors IAP (inhibitory of apoptosis proteins).
abstract: We studied the human HL60 leukemia cell line and its multidrug resistant (MDR) variant HL60R. In contrast to the HL60, HL60R showed an inability to undergo apoptosis from doxorubicin (Dox) or other different stimuli, including cisplatin, Fas ligation and serum withdrawal. HL60R cells lost surface Fas expression, but we found no evidence that Fas/FasL mediates the apoptotic effects of Dox in HL60. P-glycoprotein (P-gp) did not seem to play a major role as a specific inhibitor of apoptosis. In fact, the P-gp inhibitor verapamil reversed only partially the resistance to Dox-induced apoptosis of the MDR cells. In addition, it did not modify the rate of apoptosis induced from the other stimuli in the same cells. The expression of p53 or Bcl-2 was not different between HL60 and HL60R. However, in HL60R there was an increase in the mRNAs of inhibitory of apoptosis proteins (IAPs) like neuronal apoptosis inhibitory protein (NAIP), c-IAP-2 and survivin. Treatment with Dox or serum starvation strongly down-regulated X-linked IAP and survivin mRNAs in HL60. Cisplatin decreased NAIP and survivin mRNAs in the same cells. However, in HL60R the levels of these IAP mRNAs were much less affected by the treatments. These results support that IAPs may be involved in tumor resistance to chemotherapeutic drugs or other apoptotic agents.
authors.affiliation: Dipartimento di Scienze Farmacologiche, Università di Palermo, Policlinico P. Giaccone, Via del Vespro 129, Palermo, Italy.
authors.forename: Monica
authors.initials: M
authors.lastname: Notarbartolo
authors.forename: Melchiorre
authors.initials: M
authors.lastname: Cervello
authors.forename: Luisa
authors.initials: L
authors.lastname: Dusonchet
authors.forename: Antonella
authors.initials: A
authors.lastname: Cusimano
authors.forename: Natale
authors.initials: N
authors.lastname: D'Alessandro
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000096:biosynthesis*; D000970:Antineoplastic Agents / Q000494:pharmacology; D017209:Apoptosis; D053148:Caspase 3; D020169:Caspases / Q000096:biosynthesis; D002868:Chromosomal Proteins, Non-Histone / Q000096:biosynthesis; D002945:Cisplatin / Q000494:pharmacology; D015536:Down-Regulation; D004317:Doxorubicin / Q000494:pharmacology; D019008:Drug Resistance, Neoplasm; D005434:Flow Cytometry; D018922:HL-60 Cells; D006801:Humans; D051034:Inhibitor of Apoptosis Proteins; D020128:Inhibitory Concentration 50; D019476:Insect Proteins / Q000096:biosynthesis*; D008869:Microtubule-Associated Proteins; D009363:Neoplasm Proteins; D009419:Nerve Tissue Proteins / Q000096:biosynthesis; D051616:Neuronal Apoptosis-Inhibitory Protein; D011506:Proteins; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D000077022:Survivin; D013997:Time Factors; D014407:Tumor Cells, Cultured; D019014:fas Receptor / Q000096:biosynthesis*
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000970:Antineoplastic Agents; C107489:BIRC5 protein, human; D002868:Chromosomal Proteins, Non-Histone; D051034:Inhibitor of Apoptosis Proteins; D019476:Insect Proteins; D008869:Microtubule-Associated Proteins; C496800:NAIP protein, human; D009363:Neoplasm Proteins; D009419:Nerve Tissue Proteins; D051616:Neuronal Apoptosis-Inhibitory Protein; D011506:Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D012333:RNA, Messenger; D000077022:Survivin; D019014:fas Receptor; D004317:Doxorubicin; C505407:CASP3 protein, human; D053148:Caspase 3; D020169:Caspases; D002945:Cisplatin