Immunoassays of the metalloproteinase (MMP-2) and tissue inhibitor of metalloproteinase (TIMP 1 and 2) levels in noninvasive and metastatic PC-3 clones: effects of taxol.

We have selected and subcloned bone metastatic (PC-3 ML) and noninvasive, nonmetastatic (3 x N.I.) lines from human prostatic PC-3 parent cells. In this paper, we have compared relative levels of MMP-2 and TIMP-1 and 2 in PC-3 tumors grown in severe combined immunodeficient or SCID mice. Dot blots with polyclonal antibodies specific for MMP-2, TIMP-1 and TIMP-2 revealed that the MMP-2 levels were high in subcutaneously grown PC-3 ML clones but low in 3 x N.I. clones at days 20 and 40. The TIMP-1 levels were inversely proportional to MMP-2 in the two types of clones, respectively. The TIMP-2 levels were similar in both clones at days 20 and 40. Gelatin zymograms confirmed that PC-3 ML tumors contained MMP-2 (and not MMP-9) subcutaneously or in bone metastases in SCID mice. Slot blots of PC-3 ML bone tumors comparing MMP-2 and TIMP-1 levels showed at days 10, 15, 17, 19, 21, and 25 that the ratio of MMP-2 to TIMP-1 increased, especially at about day 21, when extensive secondary metastases to the peritoneal cavity occurred. The levels of TIMP-2 remained constant. Quantitative ELISAs confirmed the blotting data and showed that taxol blocked MMP-2 but not TIMP-1 production in these advanced tumors. We conclude that highly metastatic PC-3 ML variants contained relatively high levels of MMP-2 and low amounts of TIMP-1.