Matrix metalloproteinase-activated doxorubicin prodrugs inhibit HT1080 xenograft growth better than doxorubicin with less toxicity.
Matrix metalloproteinase (MMP)-activated prodrugs were formed by coupling MMP-cleavable peptides to doxorubicin. The resulting conjugates were excellent in vitro substrates for MMP-2, -9, and -14. HT1080, a fibrosarcoma cell line, was used as a model system to test these prodrugs because these cells, like tumor stromal fibroblasts, expressed several MMPs. In cultured HT1080 cells, simple MMP-cleavable peptides were primarily metabolized by neprilysin, a membrane-bound metalloproteinase. MMP-selective metabolism in cultured HT1080 cells was obtained by designing conjugates that were good MMP substrates but poor neprilysin substrates. To determine how conjugates were metabolized in animals, MMP-selective conjugates were given to mice with HT1080 xenografts and the distribution of doxorubicin was determined. These studies showed that MMP-selective conjugates were preferentially metabolized in HT1080 xenografts, relative to heart and plasma, leading to 10-fold increases in the tumor/heart ratio of doxorubicin. The doxorubicin deposited by a MMP-selective prodrug, compound 6, was more effective than doxorubicin at reducing HT1080 xenograft growth. In particular, compound 6 cured 8 of 10 mice with HT1080 xenografts at doses below the maximum tolerated dose, whereas doxorubicin cured 2 of 20 mice at its maximum tolerated dose. Compound 6 was less toxic than doxorubicin at this efficacious dose because mice treated with compound 6 had no detectable changes in body weight or reticulocytes, a marker for marrow toxicity. Hence, MMP-activated doxorubicin prodrugs have a much higher therapeutic index than doxorubicin using HT1080 xenografts as a preclinical model.
Albright
Charles F
CF
Bristol-Myers Squibb Pharmaceutical Research Institute, 5 Research Parkway, Wallingford, CT 06492, USA. Charlie.Albright@BMS.com
Graciani
Nilsa
N
Han
Wei
W
Yue
Eddy
E
Stein
Ross
R
Lai
Zhihong
Z
Diamond
Melody
M
Dowling
Randine
R
Grimminger
Lisa
L
Zhang
Shu-Yun
SY
Behrens
Davette
D
Musselman
Amy
A
Bruckner
Robert
R
Zhang
Mingzhu
M
Jiang
Xiang
X
Hu
Daniel
D
Higley
Anne
A
Dimeo
Susan
S
Rafalski
Maria
M
Mandlekar
Sandya
S
Car
Bruce
B
Yeleswaram
Swamy
S
Stern
Andrew
A
Copeland
Robert A
RA
Combs
Andrew
A
Seitz
Steve P
SP
Trainor
George L
GL
Taub
Rebecca
R
Huang
Pearl
P
Oliff
Allen
A
D000818:Animals; D004317:Doxorubicin / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000494:pharmacology; D004354:Drug Screening Assays, Antitumor; D064420:Drug-Related Side Effects and Adverse Reactions; D005354:Fibrosarcoma / Q000188:drug therapy* / Q000378:metabolism; D006801:Humans; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism*; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism*; D053504:Matrix Metalloproteinases, Membrane-Associated; D008666:Metalloendopeptidases / Q000378:metabolism*; D051379:Mice; D015260:Neprilysin / Q000494:pharmacology; D010446:Peptide Fragments / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D011355:Prodrugs / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D012156:Reticulocytes / Q000187:drug effects / Q000378:metabolism; D014183:Transplantation, Heterologous; D014407:Tumor Cells, Cultured
D010446:Peptide Fragments; D011355:Prodrugs; D004317:Doxorubicin; D053504:Matrix Metalloproteinases, Membrane-Associated; D008666:Metalloendopeptidases; D015260:Neprilysin; D020778:Matrix Metalloproteinase 2; D020780:Matrix Metalloproteinase 9