Design, Synthesis, and Characterization of the Antitumor Activity of Novel Ceramide Analogues

Abstract

A deficiency in apoptosis is one of the key events in the proliferation and resistance of malignant cells to antitumor agents; for these reasons, the search for apoptosis-inducing drugs represents a valuable approach for the development of novel anticancer therapies. In this study we report the first example of conformationally restrained analogues of ceramide (compounds 1-4), where the polar portion of the molecule has been replaced by a thiouracil (1, 3) or uracil (2, 4) ring. The evaluation of their biologic activity on CCRF-CEM human leukemia cells demonstrated that the most active was compound 1 followed by compound 2 (mean 50% inhibition of cell proliferation [IC(50)] 1.7 and 7.9 microM, respectively), while compounds 3 and 4 were inactive, as were uracil, thiouracil, and 5,6-dimethyluracil, the pyrimidine moieties of compounds 1-4. For comparison, the IC(50) of the reference substance, the cell-permeable C2-ceramide, was 31.6 microM. Compounds 1 and 2 and C2-ceramide were able to trigger apoptosis, as shown by the occurrence of DNA and nuclear fragmentation, and to release cytochrome c from treated cells. The treatment of female CD-1 nu/nu athymic mice bearing a WiDr human colon xenograft with the most active compound 1 at 2, 10, 50, and 200 mg/kg ip daily for 10 days resulted in an antitumor effect that was equivalent at 50 mg/kg or superior (200 mg/kg) to that of cyclophosphamide, 20 mg/kg ip daily, delivered on the same schedule, with markedly lower systemic toxicity. In conclusion, the present study demonstrates that the new ceramide analogues 1 and 2 are characterized by in vitro and in vivo antitumor activity and low toxicity.

Ceramide Induces Apoptosis and Growth Arrest of Human Glioblastoma Cells by Inhibiting Akt Signaling Pathways

“…The effect of several chemotherapeutic agents are linked to the induction of apoptosis and associated with an increase of cellular ceramide (Bieberich et al, 2000;Macchia et al, 2001). In the present study, we found that ceramide induced apoptotic cell death in U373MG cells, detected by decrease of mitochondrial membrane potential or phosphatidylserine exposure measured by Annexin V binding.…”

Novel Ceramide Analogs as Potential Chemotherapeutic Agents in Breast Cancer

“…Specifically, we have used novel ceramide analogs that are altered with respect to the degree and position of unsaturation of bonds in the sphingoid backbone of D-erythro-N-octanoyl-ceramide. Others have demonstrated that changes in ceramide's structure can result in increased efficacy of these compounds (Wieder et al, 1997;Van Overmeire et al, 2000;Macchia et al, 2001;Chun et al, 2003b). For example, Macchia et al (2001) used DNA fragmentation and release of cytochrome c to analyze the effect of replacing the polar portion of the ceramide molecule with uracil or thiouracil.…”

“…Others have demonstrated that changes in ceramide's structure can result in increased efficacy of these compounds (Wieder et al, 1997;Van Overmeire et al, 2000;Macchia et al, 2001;Chun et al, 2003b). For example, Macchia et al (2001) used DNA fragmentation and release of cytochrome c to analyze the effect of replacing the polar portion of the ceramide molecule with uracil or thiouracil. The compounds produced potent in vivo antitumor activity in a model of mouse colon cancer with few systemic side effects, demonstrating the potential of ceramide analogs as a treatment strategy.…”

Analyses structurales et spectrales du 5,6‐diméthyluracile

“…Pour cela, leséchantillons ontété analysés dans des capsules en aluminium serties; la montée en température aété réaliséesà une vitesse de 20°C. min 1 La structure du monohydrate du 5,6-diméthyluracile se présente sous la forme de feuillets parallèles au plan bc et situés aux environs de 1/4 et 3/4 suivant l'axe a. A l'intérieur d'un feuillet, la cohésion est assurée par les quatre liaisons hydrogène, et par des interactions faibles entre les groupements méthyle (la distance la plus courte .…”