ognizant Communication Corporation

Oncology Research, Volume 14, pp. 113-132
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Copyright © 2003 Cognizant Comm. Corp.
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¹Department of Medical Sciences, Division of Clinical Pharmacology, Uppsala University, SE-751 85 Uppsala, Sweden
²Department of Chemistry, Medicinal Chemistry, Göteborg University, SE-412 96 Göteborg, Sweden
³Institute of Pharmacy, Department of Medicinal Chemistry, University of Tromsø, N-9037 Tromsø, Norway
⁴Karolinska Pharmacy and ⁵Department of Oncology-Pathology, Karolinska Institutet, SE-171 76 Stockholm, Sweden
⁶Department of Oncology, Radiology and Clinical Immunology, Uppsala University Hospital, SE-751 85 Uppsala, Sweden

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.

Key words: Peptichemio; P2; J1; Melphalan; Alkylating peptides; Cytotoxicity; Cell lines

Address correspondence to Dr. Joachim Gullbo, Department of Medical Sciences, Division of Clinical Pharmacology, Uppsala University, SE-751 85 Uppsala, Sweden. E-mail: Joachim.Gullbo@medsci.uu.se

¹Division of Medical Oncology, Department of Medicine, Columbia University College of Physicians and Surgeons, New York, NY
²Institute of Genetics and Biophysics "Buzzati Traverso," CNR, Naples, Italy
³Department of Urology, Hackensack University Medical Center, Hackensack, NJ
⁴Department of Medicine, Naomi Berrie Diabetes Center, College of Physicians and Surgeons, New York, NY
⁵Department of Urology, Columbia University College of Physicians and Surgeons, New York, NY

The use of cultured tumor cells rather than original tumor tissue for the preparation of therapeutic cancer vaccines represents an obvious solution to the problem of availability of adequate quantities of autologous tumor. In this study we investigated possible changes in gene expression accompanying the transition of renal cell carcinoma cells from the original tissue to cell populations in culture. In our study we employed cDNA microarray technology to compare the gene expression pattern of ex vivo cultured renal carcinoma cells to that of the original solid tumor tissue from which the cells were derived. Using this approach we detected changes in the expression of many genes mostly related to the cell lines' physiological properties. Some of the products of those genes showing differential expression between tumor-derived cell line and original tumor are known human autoantigens or tumor-associated antigens. Furthermore, analysis of overexpressed genes revealed the presence of several transcripts with restricted normal tissue distribution, representing self-antigens with potential to elicit autoimmunity. Our results suggest that adapting tumor tissue to culture can result in changes in the level of transcripts specific for known antigens and that more information regarding the composition of tumor cells and their byproducts used in vaccine trials is needed before the efficacy and safety of such procedures can truly be determined.

Key words: cDNA microarray; Vaccines; Tumor antigens; Autoantigens

Address correspondence to Paul E. Harris, Ph.D., Division of Medical Oncology, Department of Medicine BB 20-06, College of Physicians and Surgeons, 650 West 168th Street, New York, NY 10032. Tel: (212) 305 7363; Fax: (212) 305 7348; E-mail: peh1@columbia.edu

¹CIBE-Merck Research Laboratories, Merck, Sharp & Dohme de España S.A., C/ Josefa Valcárcel, 38, Madrid 28027, Spain
²Departament de Farmacologia Facultat de Farmàcia, Universitat de València, Avgd. Vicent Andrés Estellés s/n, Burjassot 46100, València, Spain

In this study we evaluated a mono-tetrahydrofuranic subgroup of natural acetogenins that had shown in previous enzyme inhibition studies different potency trends compared with the bis-tetrahydrofuranic acetogenin subgroup. The compounds were tested against colon, breast, lung, liver, and ovarian tumor cell lines. A drug-resistant ovarian cell line was also included in the panel. In general the compounds were more potent than doxorubicin. The goal was to determine how well the mitochondrial complex I inhibition correlates with the in vitro antitumor potency of these natural mono-tetrahydrofuranic acetogenins and of some derivatives. The results indicate that both the reduction of the terminal g-lactone after its translactonization and the introduction of an hydroxylimine group in the alkyl chain, near the mono-tetrahydrofuranic moiety, increased the antitumor activity, even against the doxorubicin-resistant cell line.

Key words: Cancer; Cytotoxicity; Acetogenins; Tumor cell line growth inhibitors; Mitochondrial respiratory chain inhibitors

Address correspondence to José R. Tormo, Senior Research Chemist, CIBE-Merck Research Laboratories, Merck, Sharp & Dohme de España S.A., C/ Josefa Valcárcel, 38, Madrid 28027, Spain.  Tel: 34 91 321 04 92; E-mail: jose_tormo@merck.com

Division of Pulmonary and Critical Care Medicine, Department of Medicine, Veterans Affairs Medical Center, Indiana University School of Medicine, Indianapolis, IN 46202

Tumors such as ovarian, lung, and breast have been found to have a predilection for the pleura. Pleural mesothelial cells (PMCs) play an active role in pleural inflammation via release of cytokines. However, mechanisms whereby PMCs defend themselves against invading malignant cells are unknown. In the present study, we hypothesized that PMCs release the antiangiogenic factor endostatin and inhibit malignant cell invasion. We evaluated the endostatin levels in malignant (MAL) and congestive heart failure (CHF) pleural fluids (PF). Endostatin expression by PMC was also demonstrated by Western analysis and confocal microscopy. Our results demonstrate that CHF PF contained significantly higher levels of endostatin when compared with MAL PF. PMCs alone released a significantly greater amount of endostatin when compared with ovarian cancer cells (OCCs). When the PMC were cocultured with OCCs without contact, there was an increase in the endostatin production. However, when the PMCs were cocultured in direct contact with OCCs the endostatin levels significantly decreased. Endostatin production was upregulated in the presence of tumor cells but not when OCCs were adherent to underlying PMC monolayer. Immunofluorescent staining of PMCs for endostatin correlated with endostatin release. These findings suggest that PMCs play a key role in the antiangiogenesis process by producing endostatin in the pleural space, and thus preventing tumor spread and metastasis in the pleura.

Key words: Pleural mesothelial cells; Endostatin; Metastasis; Ovarian cancer; Angiogenesis

*Current address: Division of Pulmonary & Critical Care Medicine, College of Medicine, Veterans Affairs Medical Center, University of Florida, P.O. Box 100225, Bainesville, FL 32610-0225

#Address correspondence to Veena B. Antony, M.D., Division of Pulmunary & Critical Care Medicine, College of Medicine, University of Florida, P.O. Box 100225, Gainesville, FL 32610-0225. Fax: (352) 271-4559; E-mail: antonvb@medicine.ufl.edu

¹Department of Dermatology, Yale University School of Medicine, New Haven, CT 06520
²Department of Cellular and Molecular Biology and Pathogenic Bioagents, Faculty of Medicine of Ribeirao Preto, University of São Paolo, São Paulo 14049-900, Brazil

It was shown previously that a majority of hybrids produced by in vitro fusion of normal macrophages with Cloudman S91 melanoma cells displayed macrophage-specific glycosylation, especially increased GnT-V activity, b1,6 branch formation in glycoproteins, accompanied by enhanced metastatic potential in vivo and motility in vitro. These hybrids also express upregulated melanocortin-1 receptor (MC1-R) activity and exhibit increased motility after melanocyte-stimulating hormone (MSH) treatment. In this report, we show that MSH-mediated stimulation of motility is mediated through enhanced expression of c-Met proto-oncogene. In metastatic hybrids c-Met expression is induced by MSH, and addition of c-Met neutralizing antibody to cells inhibits MSH-induced motility but not the basal motility of the cells. Furthermore, abrogation of the chemoattractant gradient concentration by addition of hepatocyte growth factor (HGF) recombinant protein, a cognate ligand of c-Met receptor, reduces the MSH-induced effect on motility. A similar result was also obtained by the addition of blocking anti-aHGF antibody in the chemoattractant chamber. Again, the metastatic hybrids, but not the nonmetastatic hybrids or parental melanoma cells, showed significant motile response to rHGF chemoattractant, and that motility is further induced when cells were stimulated with MSH/isobutylmethyl xanthine (IBMX). Synergistic stimulation on motility was also observed with those hybrids treated with MSH/IBMX and when rHGF and fibronectin (FN), in combination, were used as chemoattractants. These indicate that MSH/IBMX-induced motility might involve c-Met pathways as well as extracellular matrix (ECM)/integrin pathways in a cooperative fashion. Ets-1, a transcription factor involved in the expression of c-Met, is also found to be induced in metastatic hybrids after exposure to MSH/IBMX. Implication of the result is discussed in light of the role of c-Met and its interacting proteins in the development of metastatic phenotypes and its therapeutic intervention.

Key words: Hybrid; Metastasis; Motility; c-Met proto-oncogene; Melanocyte-stimulating hormone (MSH)

Address correspondence to Ashok K. Chakraborty, Ph.D., Department of Dermatology, LCI 505, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520. Tel: (203) 785-4963; Fax: (203) 785-7637; E-mail: ashok.chakraborty@yale.edu