Timár F, Botyánszki J, Süli-Vargha H, Babó I, Oláh J, Pogány G, Jeney A
First Institute of Pathology and Experimental Cancer Research, Semmelweis University of Medicine, Budapest, Hungary.
Cancer Chemother Pharmacol. 1998;41(4):292-8. doi: 10.1007/s002800050742.
The objective of the present study was to examine the relevance of collagenase in the antitumor action of a melphalan peptide (MHP) with a collagenase-cleavable sequence. The question was addressed as to whether collagenase may act as an activator or a target in the antiproliferative mechanism of MHP.
Melphalan was inserted into peptides representing the sequence Pro-Gln-Gly-Ile-Ala.Gly of the collagenase-cleavable site in collagens. Changes in growth and collagenase IV activities of HT-1080, HT-29, HT-168, and MCF-7 cell cultures were investigated.
The present investigations provide data indicating that Pro-Gln-Gly-Ile-Mel-Gly (melphalan hexapeptide, MHP) is a substrate for both bacterial and 72-kDa type IV collagenases and that in this way it can generate Ile-Mel-Gly (melphalan tripeptide, MTP) of higher cytotoxic potency. Indeed, the formation of MTP was detected in the conditioned medium of HT-1080, a collagenase IV-producing human fibrosarcoma. In a comparison of equimolar concentrations of melphalan and its two peptide derivatives (MHP and MTP), superior antiproliferative action of MTP was seen in HT-29, HT-1080, and HT-168 tumor cell cultures. However, the relatively modest cytostatic actions of MHP were increased when bacterial collagenase was added to the cell cultures. After melphalan treatment, reduced levels of both 92 and 72-kDa type IV collagenases were seen in the HT-1080 cell cultures. However, the reduction of collagenase activity and the cell counts did not run parallel in the MTP- or MHP-treated cultures; indeed, collagenase activity related to cell numbers showed an elevated level.
As the conversion of MHP to the more toxic MTP was detected in the presence of collagenases, it is possible that collagenase-directed activation of prodrugs may be a promising approach for the development of more selective cytostatic drugs against malignant tumors with high collagenase activities.
本研究的目的是检验胶原酶在具有胶原酶可切割序列的美法仑肽（MHP）抗肿瘤作用中的相关性。研究了胶原酶在MHP抗增殖机制中是否可作为激活剂或靶点这一问题。
将美法仑插入代表胶原蛋白中胶原酶可切割位点序列Pro-Gln-Gly-Ile-Ala.Gly的肽段中。研究了HT-1080、HT-29、HT-168和MCF-7细胞培养物的生长变化及IV型胶原酶活性。
目前的研究提供的数据表明，Pro-Gln-Gly-Ile-Mel-Gly（美法仑六肽，MHP）是细菌和72 kDa IV型胶原酶的底物，通过这种方式它可以生成具有更高细胞毒性效力的Ile-Mel-Gly（美法仑三肽，MTP）。事实上，在产生IV型胶原酶的人纤维肉瘤HT-1080的条件培养基中检测到了MTP的形成。在美法仑及其两种肽衍生物（MHP和MTP）等摩尔浓度的比较中，在HT-29、HT-1080和HT-168肿瘤细胞培养物中观察到MTP具有更强的抗增殖作用。然而，当向细胞培养物中添加细菌胶原酶时，MHP相对较弱的细胞生长抑制作用增强。美法仑处理后，HT-1080细胞培养物中92 kDa和72 kDa IV型胶原酶的水平均降低。然而，在MTP或MHP处理的培养物中，胶原酶活性的降低与细胞计数并不平行；实际上，与细胞数量相关的胶原酶活性显示出升高。
由于在胶原酶存在的情况下检测到MHP向毒性更强的MTP的转化，胶原酶导向的前药激活可能是开发针对具有高胶原酶活性的恶性肿瘤的更具选择性的细胞生长抑制药物的一种有前景的方法。
