TY - JOUR
T1 - Co-administration of probenecid, an inhibitor of a cMOAT/MRP-like plasma membrane ATPase, greatly enhanced the efficacy of a new 10-deazaaminopterin against human solid tumors in vivo
AU - Sirotnak, F. M.
AU - Wendel, H. G.
AU - Bornmann, W. G.B.
AU - Tong, W. P.
AU - Miller, V. A.
AU - Scher, H. I.
AU - Kris, M. G.
PY - 2000
Y1 - 2000
N2 - Earlier studies from this laboratory have shown that the uricosuric agent probenecid (PBCD) will inhibit the extrusion of folate analogues from tumor ceils mediated by a plasma membrane ATPase resembling the canicular multispecific organic anion transporter/multidrug resistance-related protein (MRP) family of ATP binding cassette transporters. This inhibition of this outwardly directed membrane ATPase has been shown to have a favorable impact upon the cellular pharmacokineties, cytotoxicity, and efficacy of methotrexate in vivo. In an extension of these earlier studies, which had focused only on murine aseites tumors, we now report that parental co-administration of PBCD will also enhance net intracellular accumulation in vitro and intracellular persistence in vivo of a new falate analogue, 10-propargyl-10-deazaaminopterin (PDX) in tumor cells. This resulted in marked enhancement of the efficacy of PDX against murine and human lung neoplasms and human prostate and mammary neoplasms growing as solid tumors in mice. As possible ATPases targeted by PBCD, all of these tumors expressed MRP-1, -4, and -7 genes, with expression of MRP-4 being greatest in each case. Four other MRP genes were expressed to a variable extent in some tumors but not others. The therapeutic enhancement of PDX by PBCD was manifested as tumor regression, where PDX alone was only growth inhibitory (A549 NSCL tumor), or as a substantial increase (3-4-fold) in overall regression and/or number of complete regressions (Lewis and LX-1 lung, PC-3 and TSU-PR1 prostate, and MX-1 mammary tumors) compared to PDX alone. Also, only in the case of PDX with PBCD, a significant number of mice transplanted with LX-1 or MX-1 tumors that experienced complete regression did not have regrowth of their tumor. In view of these results, clinical trials of tiffs therapeutic modality appear to be warranted, especially in the case of new more efficacious folate analogues that are also permeants for this canicular multispecific organic anion transporter/MRP-like plasma membrane ATPase.
AB - Earlier studies from this laboratory have shown that the uricosuric agent probenecid (PBCD) will inhibit the extrusion of folate analogues from tumor ceils mediated by a plasma membrane ATPase resembling the canicular multispecific organic anion transporter/multidrug resistance-related protein (MRP) family of ATP binding cassette transporters. This inhibition of this outwardly directed membrane ATPase has been shown to have a favorable impact upon the cellular pharmacokineties, cytotoxicity, and efficacy of methotrexate in vivo. In an extension of these earlier studies, which had focused only on murine aseites tumors, we now report that parental co-administration of PBCD will also enhance net intracellular accumulation in vitro and intracellular persistence in vivo of a new falate analogue, 10-propargyl-10-deazaaminopterin (PDX) in tumor cells. This resulted in marked enhancement of the efficacy of PDX against murine and human lung neoplasms and human prostate and mammary neoplasms growing as solid tumors in mice. As possible ATPases targeted by PBCD, all of these tumors expressed MRP-1, -4, and -7 genes, with expression of MRP-4 being greatest in each case. Four other MRP genes were expressed to a variable extent in some tumors but not others. The therapeutic enhancement of PDX by PBCD was manifested as tumor regression, where PDX alone was only growth inhibitory (A549 NSCL tumor), or as a substantial increase (3-4-fold) in overall regression and/or number of complete regressions (Lewis and LX-1 lung, PC-3 and TSU-PR1 prostate, and MX-1 mammary tumors) compared to PDX alone. Also, only in the case of PDX with PBCD, a significant number of mice transplanted with LX-1 or MX-1 tumors that experienced complete regression did not have regrowth of their tumor. In view of these results, clinical trials of tiffs therapeutic modality appear to be warranted, especially in the case of new more efficacious folate analogues that are also permeants for this canicular multispecific organic anion transporter/MRP-like plasma membrane ATPase.
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M3 - Article
C2 - 10999764
AN - SCOPUS:0033813261
SN - 1078-0432
VL - 6
SP - 3705
EP - 3712
JO - Clinical Cancer Research
JF - Clinical Cancer Research
IS - 9
ER -