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- Gullbo, Joachim, et al.
(författare)
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Antitumor activity of the novel melphalan containing tripeptide J3 (L-prolyl-melphalanyl-p-L-fluorophenylalanine ethyl ester) : Comparison with its m-L-sarcolysin analogue P2
- 2003
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Ingår i: Molecular Cancer Therapeutics. - 1535-7163 .- 1538-8514. ; 2:12, s. 1331-1339
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Tidskriftsartikel (refereegranskat)abstract
- Peptichemio (PTC), a mixture of six oligopeptides all containing m-L-sarcolysin, has previously shown impressive results in clinical trials. The tripeptide P2 (L-prolyl-m-L-sarcolysyl-p-L-fluorophenylalanine ethyl ester) has been suggested as the main contributor to PTC activity. In contrast to its analogue melphalan, m-L-sarcolysin never reached clinical use. To allow a direct comparison, the corresponding melphalan containing tripeptide J3 (L-prolyl-L-melphalanyl-p-L-fluorophenylalanine ethyl ester) was synthesized and its activity was compared with that of P2; the activities of melphalan and m-L-sarcolysin were studied in parallel. Cytotoxic activity in human tumor cell lines and some fresh human tumor specimens were analyzed as well as effects on cellular metabolism, macromolecular synthesis, and preliminary evaluation of the cell death characteristics. The results show that melphalan and m-L-sarcolysin display similar activity in these systems and that the tripeptides were more active than their parent monomers. Surprisingly however, the melphalan containing tripeptide J3 demonstrated a significantly more rapid and stronger activity than the m-L-sarcolysin analogue P2. Finally, the in vivo toxicity and activity of melphalan and J3 were investigated in mice bearing human leukemia cells in s.c. fibers. The in vitro results seem translatable into the in vivo situation, demonstrating better antileukemic effect of J3 but similar side effects as melphalan.
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- Gullbo, Joachim, et al.
(författare)
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Antitumor efficacy and acute toxicity of the novel dipeptide melphalanyl-p-L-fluorophenylalanine ethyl ester (J1) in vivo.
- 2004
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Ingår i: Investigational new drugs. - 0167-6997. ; 22:4, s. 411-20
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Tidskriftsartikel (refereegranskat)abstract
- The novel alkylating dipeptide melphalanyl-p-L-fluorophenylalanine ethyl ester (J1) was evaluated for acute toxicity and antitumor activity in mice, with melphalan as a reference. To determine a safe and tolerable dose for efficacy studies the acute toxicity following intravenous injection in the tail vein was monitored using a 14-day schedule with up to four doses. The highest tested dose, 25 micromoles/kg, was considered close to this level, with minor effects on body weight gain but significant effects on hematological parameters. Melphalan and J1 appeared equitoxic with no statistically significant differences. Subsequently a mouse hollow fiber model was employed with subcutaneous implantation of fibers containing human tumor cells. Three different human tumor cell lines as well as two samples of primary human tumor cells (ovarian carcinoma and chronic lymphatic leukemia) were used as tumor models. At the dose level tested there was a marked and statistically significant decrease in both T-cell leukemia CCRF-CEM and small cell lung cancer NCI-H69 tumor cell growth and viability in response to J1 as compared with both placebo and melphalan treated groups. In primary ovarian carcinoma cells only J1 treatment resulted in significant tumor regression (net cell kill). In summary the results indicate that, despite an expected short half time in the blood circulation, the promising in vitro data from the previous studies of J1 seems translatable into the in vivo situation. At equal doses of alkylating units J1, compared to melphalan, was more active in the mouse hollow-fiber model, but showed similar general toxicity.
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- Gullbo, Joachim, 1971-
(författare)
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Preclinical Development of New Alkylating Oligopeptides for Cancer Therapy
- 2003
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Oligopeptides can be used to carry cytotoxic agents in cancer chemotherapy, using tumour-associated proteins as the molecular target for selectivity. During the seventies and eighties Peptichemio, a cocktail of six alkylating oligopeptides carrying m-L-sarcolysin, was investigated in a wide variety of human malignancies. Positive clinical results were suggested to result from rapid and effective DNA-crosslinking following uptake in neoplastic cells, but also from antimetabolic properties of the drug. Although m-L-sarcolysin never reached widespread clinical use, the well established para-isomer melphalan still, after nearly fifty years, has a place in cancer chemotherapy.The present study was undertaken to synthesise the melphalan containing analogue of the tripeptide P2 (L-prolyl-m-L-sarcolysyl-p-L-fluorophenylalanine ethyl ester, the main contributor to Peptichemio’s activity) and similar compounds, preferably dipeptides. The new compounds compared favourably with melphalan, m-L-sarcolysin and P2, considering their potency in vitro. Structure activity relationship analysis showed that the activity of melphalan dipeptides depended on the amino acid composition, sequence and end group modifications, but only to a minor degree on lipophilicity. Results suggested that the dipeptides, to exert their full cytotoxic activity, had to interact with specific biomolecules such as dipeptide transporters or peptidases. Although no active transport could be demonstrated the influence of peptide hydrolysis was obvious, thereby suggesting a rationale for increased activity as well as potential tumour selectivity in comparison with melphalan.Preliminary in vivo studies in mice supported the results, despite equal alkylating capacity the dipeptide J1 (melphalanyl-p-L-fluorophenylalanine ethyl ester) and the tripeptide J3 (L-prolyl-melphalanyl-p-L-fluorophenylalanine ethyl ester) were more active than was melphalan on human tumour cells implanted in test animals although all drugs produced expected side effects, notably leukopenia, of similar magnitude.In conclusion, oligopeptide derivatives of melphalan seem to provide improved cytotoxic activity and therapeutic index. Further development of such oligopeptides for clinical use seems worthwhile.
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