Flow cytometric analysis of P-glycoprotein expression and drug efflux in human soft tissue and bone sarcomas.
Twenty-two fresh surgical specimens of human sarcomas (soft tissue and bone) from 20 patients were analyzed by flow cytometry for the expression of drug resistance-related P-glycoprotein (P-gp) and cellular daunorubicin (DNR) accumulation with or without the presence of DNR efflux blockers. Single-cell suspensions prepared from the tumor specimens were analyzed by dual-color flow cytometry after reaction with MRK-16 (anti-P-gp) and anti-CD45 (pan-leukocyte) antibodies. MRK-16 reactivity of tumor cells was evaluated after exclusion of CD45-positive cells by electronic gates. Parallel samples were incubated with DNR alone or in combination with DNR efflux blockers, verapamil (VPL), or dipyridamole (DPD) for determination of cellular DNR accumulation and the effect of the efflux blockers. Extensive heterogeneity was observed in both P-gp expression and DNR accumulation of the tumor specimens examined. Eight of the 22 tumor specimens had significant numbers of P-gp-positive cells. In three of the eight P-gp-positive tumors, cellular DNR accumulation was significantly increased by co-incubation with the efflux blockers VPL or DPD. These results indicate that both quantitative and functional analysis of P-gp expression may be essential in determining the cellular drug resistance phenotype of tumor cells and its correlation with therapeutic outcome.
Kunikane
H
H
Department of Radiation Oncology and Sylvester Comprehensive Cancer Center, University of Miami School of Medicine, Florida 33101, USA.
Zalupski
M M
MM
Ramachandran
C
C
KuKuruga
M A
MA
Lucas
D
D
Ryan
J R
JR
Krishan
A
A
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000032:analysis* / Q000096:biosynthesis; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000903:Antibiotics, Antineoplastic / Q000032:analysis / Q000493:pharmacokinetics* / Q000627:therapeutic use; D000906:Antibodies; D001859:Bone Neoplasms / Q000188:drug therapy / Q000473:pathology* / Q000601:surgery; D002648:Child; D003630:Daunorubicin / Q000032:analysis / Q000493:pharmacokinetics* / Q000627:therapeutic use; D019008:Drug Resistance, Neoplasm; D005260:Female; D005434:Flow Cytometry / Q000379:methods; D018219:Histiocytoma, Benign Fibrous / Q000473:pathology; D006801:Humans; D007890:Leiomyosarcoma / Q000473:pathology; D017493:Leukocyte Common Antigens / Q000032:analysis; D008080:Liposarcoma / Q000473:pathology; D008297:Male; D008875:Middle Aged; D012516:Osteosarcoma / Q000473:pathology; D011237:Predictive Value of Tests; D011379:Prognosis; D012509:Sarcoma / Q000188:drug therapy / Q000473:pathology* / Q000601:surgery; D012983:Soft Tissue Neoplasms / Q000188:drug therapy / Q000473:pathology* / Q000601:surgery
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000903:Antibiotics, Antineoplastic; D000906:Antibodies; D017493:Leukocyte Common Antigens; D003630:Daunorubicin