Elimination of drug-resistant myeloma tumor cell lines by monoclonal
anti-P-glycoprotein antibody and rabbit complement
SS Kulkarni, ZM Wang, G Spitzer, M Taha, H Hamada, T Tsuruo and KA Dicke
Department of Hematology, University of Texas M.D. Anderson Cancer Center,
Houston 77030.
The effectiveness of ex vivo chemotherapy with drugs, such as vincristine,
etoposide, and Adriamycin (doxorubicin, Adria Labs, Columbus, OH) for
elimination of residual tumor cells from human bone marrow grafts could be
undermined by the presence of multidrug- resistant tumor cells in the bone
marrow. Therefore, to supplement chemoseparation, we investigated whether
MRK-16, a monoclonal antibody (MoAb) to the surface moiety of multidrug
resistance-associated P- glycoprotein antigen, can eliminate drug-resistant
tumor cells in the presence of rabbit complement (RC). Two doxorubicin
(DOX)-resistant human myeloma tumor cell line, 8226/DOX40 (resistant to 4 x
10(-7) mol/L DOX) and 8226/DOX6 (6 x 10(-8) mol/L DOX) with high and low
amounts of cell surface P-glycoprotein, respectively, and the drug-
sensitive parent cell line 8226/S were used as tumor models in this study.
Using the limiting dilution assay, we have shown that three cycles of
treatment with 25 micrograms/mL of MRK-16 MoAb and a 1:4 final dilution of
RC eliminated 2.90 +/- 0.10 logs of 8226/DOX40 cells and 1.94 +/- 0.18 logs
of 8226/DOX6 cells. One and two cycles of treatment were less effective,
eliminating 0.47 +/- 0.40 and 1.94 +/- 0.36 logs of 8226/DOX40 and 0.12 +/-
0.20 and 1.63 +/- 0.58 logs of 8226/DOX6 cells, respectively. The 8226/S
cell growth was unaffected by one to three cycles of treatment. The cell
kill was not impaired when the antibody plus complement treatment was
carried out on a mixture of 8226/DOX40 or 8226/DOX6 cells with a ninefold
excess of irradiated bone marrow mononuclear cells (MNCs). The three cycles
of treatment with antibody plus complement did not adversely affect
granulocyte- macrophage colony-forming unit (GM-CFU) survival in
hematologically normal marrows (92.5% to 104% survival) or in myeloma
patient marrows (85% to 100%). These results show that it is possible to
eliminate drug- resistant myeloma tumor cell lines from the admixed human
bone marrow by treatment with MRK-16 MoAb plus RC. This method could prove
to be effective for elimination of other drug-resistant tumor cell lines
including those of leukemia and solid tumors, and will be further useful
for supplementing chemopurging, and immunopurging of bone marrow with other
antitumor cell antibodies.
Volume 74,
Issue 6,
pp. 2244-2251,
11/01/1989
Copyright © 1989 by The American Society of Hematology
