| 21. |
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| 22. |
- 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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| 23. |
- Gullbo, Joachim, et al.
(författare)
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Structure activity relationship for alkylating dipeptide nitrogen mustard derivatives
- 2003
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Ingår i: Oncology Research. - : Computers, Materials and Continua (Tech Science Press). - 0965-0407 .- 1555-3906. ; 14:3, s. 113-132
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Tidskriftsartikel (refereegranskat)abstract
- The strategy of using small peptides for effective targeting of tumor cells in chemotherapy has proven beneficial. Recently we showed that J1 (L-melphalanyl-p-L-fluorophenylalanine ethyl ester), an alkylating nitrogen mustard-containing dipeptide, exhibited strong cytotoxic activity in fresh human tumor samples in addition to rapid and pronounced inhibition of macromolecular syntheses and cellular respiration in the human tumor lymphoma cell line U-937 GTB. In this study, an additional series of 17 nitrogen mustard-containing dipeptides has been synthesized and analyzed for cytotoxic activity in a panel of 10 human tumor cell lines. The results were compared to the single amino acid mustard derivative melphalan and its ethyl and isopropyl esters. Also P2 (L-prolyl-m-L-sarcolysyl-p-L-fluorophenylalanine ethyl ester), a tripeptide that previously has shown impressive effects in human tumor cells, was used as reference. The tested compounds displayed various activities in the different cell lines but also showed a high correlation, indicating a similar mechanism of action. Factors like amino acid composition, amino acid sequence, modifications of the C- and N-termini, and to a minor extent the lipophilicity of the dipeptide derivatives appear to influence the in vitro activity. The results indicate that the activity of these compounds not only relies on their chemical reactivity, but also on active biological interactions such as transport across membranes and/or enzymatic liberation of reactive molecular entities.
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| 24. |
- Hassan, Saadia Bashir, et al.
(författare)
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A hollow fiber model for in vitro studies of cytotoxic compounds : Activity of the cyanoguanidine CHS 828
- 2001
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Ingår i: Anti-Cancer Drugs. - 0959-4973 .- 1473-5741. ; 12:1, s. 33-42
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Tidskriftsartikel (refereegranskat)abstract
- The hollow fiber assay is currently used as an in vivo model for anticancer drug screening in nude mice, but it can also be used as an in vitro model. In the current study, an in vitro hollow fiber model was used to study the effect and mode of induced cell death of a new cyanoguanidine, CHS 828. Human leukemia, adenocarcinoma and lymphoma cell lines as well as primary cultures of human tumor cells from patients with chronic lymphocytic leukemia (CLL) and ovarian cancer (OC) and normal human lymphocytes were cultured in semipermeable hollow fibers. The fibers were incubated for 3 or 14 days prior to CHS 828 exposure for 72 h, followed by determination of living cell density by MTT staining. For cell morphology, using harvested cultures on cytospin slides had technical advantages compared to using paraffin sections of the formalin-fixed fibers. CHS 828 showed higher antitumor activity on CLL and normal human lymphocyte cultures compared to OC cultures, and cell lines cultured 3 days were more sensitive than those cultured 14 days. Morphological examination of CHS 828-treated cultures revealed a mixture of apoptosis and necrosis.
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| 25. |
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| 26. |
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| 27. |
- Henningsson, Anja, et al.
(författare)
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Population pharmacokinetic modelling of unbound and total plasma concentrations of paclitaxel in cancer patients
- 2003
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Ingår i: European Journal of Cancer. - 0959-8049 .- 1879-0852. ; 39:8, s. 1105-1114
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to validate and further develop a mechanism-based population pharmacokinetic model for paclitaxel (Taxol; Bristol-Myers Squibb Co, Princeton, NJ, USA) based on the knowledge of Cremophor EL (CrEL) micelle entrapment and to evaluate the exposure/toxicity relationships. Paclitaxel (total and unbound) and CrEL concentrations were obtained according to a sparse sampling scheme with on average only 3.5 samples per course from 45 patients with solid tumours who received 3-hour infusions of paclitaxel (final dose range 112-233 mg/m(2)). The present data were predicted well by the mechanism-based model. In addition, bilirubin and body size were found to be significant as covariates. A change in body surface area (BSA) of 0.1 m(2) typically caused a change in clearance (CL) of 22.3 l/h and an increase in bilirubin of 10 microM typically caused a decrease in CL of 41 l/h. Toxicity was best described by a threshold model. In conclusion, even with a sparse sampling scheme, the same mechanism-based binding components as in the previously developed model could be identified. Once the CrEL and total paclitaxel plasma concentrations are known, the unbound concentrations, which are more closely related to the haematological toxicity, can be predicted.
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| 28. |
- Högberg, Thomas, 1947-, et al.
(författare)
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A systematic overview of chemotherapy effects in ovarian cancer
- 2001
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Ingår i: Acta Oncologica. - : Informa UK Limited. - 0284-186X .- 1651-226X. ; 40:2-3, s. 340-360
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Tidskriftsartikel (refereegranskat)abstract
- A systematic review of chemotherapy trials in several tumour types was performed by The Swedish Council of Technology Assessment in Health Care (SBU). The procedures for the evaluation of the scientific literature are described separately (Acta Oncol 2001, 40: 155-65). This overview on chemotherapy for epithelial ovarian cancer is based on a total of 176 scientific reports. Five meta-analyses including 17 291 patients, 33 prospective randomised studies including 12 340 patients, 36 prospective studies including 3593 patients and one retrospective study including 421 patients. The studies include approximately 33 642 patients. The conclusions reached can be summarized into the following points: ò Radically operated patients with low-risk early ovarian cancer (stage IA or IB non-clear-cell well-differentiated carcinomas or borderline tumours) have a very good prognosis and there is no indication for adjuvant therapy. ò Radically operated patients with high-risk early ovarian cancer (clear cell carcinomas or FIGO stage IA or IB moderately or poorly differentiated carcinomas or stage IC) have a substantial risk for micrometastatic disease. However, the role of adjuvant chemotherapy is unclear and such therapy should, thus, only be used within clinical trials. ò The median overall survival for patients with advanced (FIGO stages II-IV) ovarian cancer randomised to paclitaxel/platinum-containing chemotherapy in three large studies ranged between 36-39 months. Compared with historical data, this represents a six to seven times longer median survival time than after surgery only. The probability for long-term survival for patients treated with a paclitaxel/platinum combination is too early to define. ò In two prospective randomised trials in advanced ovarian cancer, paclitaxel in combination with cisplatin has provided a survival benefit over cyclophosphamide/cisplatin. Based on these trials, paclitaxel/cisplatin is considered to be the standard treatment. ò This choice of standard therapy might, however, be questioned based on the results of the hitherto largest randomised study in advanced ovarian cancer, ICON3, which is, as yet only available in abstract form. It compared paclitaxel/carboplatin with carboplatin only or a platinum combination (cyclophosphamide/doxorubicin/cisplatin). There were no statistically significant differences in progression-free or overall survival. The drug regimen in the control arms of the previous studies showing superiority of the paclitaxel-cisplatin combination may not have been the optimal non-paclitaxel platinum-containing regimen. ò Three randomised studies have compared carboplatin/paclitaxel with cisplatin/paclitaxel. All three are hitherto only published as abstracts with short follow-up precluding survival analyses. None of them shows any difference in response rates. All three show less toxicity and one also better quality of life with carboplatin. Thus, there are preliminary data supporting the substitution of cisplatin with carboplatin. ò Intraperitoneal therapy with cisplatin caused improved survival compared with intravenous therapy in one ramdomised study. Further studies have shown trends to better survival and longer progression-free interval with intraperitoneal therapy. The accrual to studies on intraperitoneal chemotherapy has been poor reflecting that it is a cumbersome and not easily accepted treatment. ò In advanced ovarian cancer, no convincing advantage has been shown from more dose-intensive chemotherapy, without cytokines or bone marrow stem cell support, compared with standard doses. ò High response rates are achieved with high-dose chemotherapy with stem cell support in the salvage situation but response duration is short. Phase III studies evaluating high-dose chemotherapy in the first-line situation are ongoing. Until supportive controlled clinical trials are presented, high-dose chemotherapy should be confined to clinical trials. ò Tumour response is frequently observed on re-treatment with the same drugs as given first-line in patients sensitive to first-line platinum-based chemotherapy with a long progression-free interval. Thus, in these patients treatment with a platinum/ paclitaxel combination might be recommended, albeit based on limited data. In patients resistant to first-line therapy, a number of single agents induce tumour responses in the range of 10-30%. The literature does not permit general treatment recommendations in these patients, which are recommended to be included in controlled clinical trials.
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