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The antiproliferative action of a melphalan hexapeptide with collagenase-cleavable site
F Timár1, J Botyánszki, H Süli-Vargha
1First Institute of Pathology and Experimental Cancer Research, Semmelweis University of Medicine, Budapest, Hungary.
Purpose:
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.
Methods:
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.
Results:
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.
Conclusions:
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.
Insights
Collagenase enzymes activate melphalan peptide (MHP) into a more potent cytotoxic agent (MTP), enhancing antitumor activity. This collagenase-directed prodrug activation shows promise for developing selective cancer therapies.
Area of Science:
- Biochemistry
- Molecular Biology
- Oncology
Background:
- Melphalan peptide (MHP) is a prodrug designed with a collagenase-cleavable sequence.
- Collagenases are enzymes that degrade collagen, playing roles in tissue remodeling and disease.
- Understanding the interaction between MHP and collagenases is crucial for evaluating MHP's antitumor efficacy.
Purpose of the Study:
- To investigate the role of collagenase in the antitumor activity of melphalan peptide (MHP).
- To determine if collagenase acts as an activator or a target in MHP's antiproliferative mechanism.
- To assess the potential of collagenase-directed activation for developing targeted cancer therapies.
Main Methods:
- Synthesized melphalan hexapeptide (MHP) incorporating a collagenase-cleavable sequence (Pro-Gln-Gly-Ile-Mel-Gly).
- Investigated the effects of MHP and its derivative melphalan tripeptide (MTP) on cell growth and collagenase IV activity in various cancer cell lines (HT-1080, HT-29, HT-168, MCF-7).
- Assessed the enzymatic activity of bacterial collagenase and 72-kDa type IV collagenases on MHP.
Main Results:
- Melphalan hexapeptide (MHP) was confirmed as a substrate for bacterial and 72-kDa type IV collagenases, yielding the more potent cytotoxic melphalan tripeptide (MTP).
- MTP exhibited superior antiproliferative effects compared to MHP and melphalan alone across multiple tumor cell lines.
- The addition of bacterial collagenase enhanced the cytostatic action of MHP, and melphalan treatment reduced type IV collagenase levels, though not in parallel with cell count reduction.
Conclusions:
- The conversion of MHP to the more toxic MTP by collagenases supports the hypothesis of collagenase-directed prodrug activation.
- This approach holds promise for developing more selective cytostatic drugs targeting tumors with high collagenase activity.
- Further research into collagenase-activated prodrugs could lead to improved cancer treatment strategies.