Relaxation effect of synthetic ceramide analogues in cat esophageal smooth muscle cells

The effect of synthetic ceramide analogues on gastritis and esophagitis in rats

The effects of ceremide analogues on esophagitis and gastritis in rats were examined. Gastritis induced by indomethacin was significantly reduced after CY3325 and CY3723 treatment, whereas other analogues had no effect. The amount of malondialdehyde in gastritis was significantly reduced by CY3325 or CY 3723. CY3325 or CY 3723 decreased the glutathione levels in gastritis. The myeloperoxidase level in gastritis is increased, and its increment was decreased by CY3325 and CY3723. In reflux esophagitis, the ulceration was decreased by CY3325, CY3723. The gastric volume and acid output are reduced, whereas the pH value is increased by CY3325 or CY3723 after esophagitis. These results suggest that ceramide analogues, CY3325 and CY3723, can prevent the development of gastritis and reflux esophagitis in rats.

Cytotoxicities and Quantitative Structure Activity Relationships of B13 Sulfonamides in HT-29 and A549 Cells

B13 analogues are being considered as therapeutic agents for cancer cells, since B13 is a ceramide analogue and inhibits ceramidase to promote apoptosis in cancer cells. B13 sulfonamides are assumed to have biological activity similar to B13, since they are made by bioisosterically substituting the carboxyl moiety of B13 with sulfone group. Twenty B13 sulfonamides were evaluated for their in vitro cytotoxicities against human colon cancer HT-29 and lung cancer A549 cell lines using MTT assays. Replacement of the amide group with a sulfonamide group increased cytotoxicity in both cancer cell lines. The sulfonamides with long alkyl chains exhibited activities two to three times more potent than that of B13 and compound (15) had the most potent activity with IC₅₀ values of 27 and 28.7µM for HT-29 and A549, respectively. The comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA) were used to carry out QSAR molecular modeling of these compounds. The predictive CoMSIA models for HT-29 and A549 gave cross-validated q2 values of 0.703 and 0.830, respectively. From graphical analysis of these models, we suppose that the stereochemistry of 1,3-propandiol is not important for activity and that introduction of a sulfonamide group and long alkyl chains into B13 can increase cytotoxicity.

MAPKs represent novel therapeutic targets for gastrointestinal motility disorders

The number of patients suffering from symptoms associated with gastrointestinal (GI) motility disorders is on the rise. GI motility disorders are accompanied by alteration of gastrointestinal smooth muscle functions. Currently available drugs, which can directly affect gastrointestinal smooth muscle and restore altered smooth muscle contractility to normal, are not satisfactory for treating patients with GI motility disorders. We have recently shown that ERK1/2 and p38MAPK signaling pathways play an important role in the contractile response not only of normal intestinal smooth muscle but also of inflamed intestinal smooth muscle. Here we discuss the possibility that ERK1/2 and p38MAPK signaling pathways represent ideal targets for generation of novel therapeutics for patients with GI motility disorders.

Cytotoxic Activity and Structure Activity Relationship of Ceramide Analogues in Caki-2 and HL-60 Cells

B13, a ceramide analogue, is a ceramidase inhibitor and induces apoptosis to give potent anticancer activity. A series of thiourea B13 analogues was evaluated for their in vitro cytotoxic activities against human renal cancer Caki-2 and leukemic cancer HL-60 in the MTT assay. Some compounds (12, 15, and 16) showed stronger cytotoxicity than B13 and C6-ceramide against both tumor cell lines, and compound (12) gave the most potent activity with IC(50) values of 36 and 9 µM, respectively. Molecular modeling of thiourea B13 analogues was carried out by comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA). We obtained highly reliable and predictive CoMSIA models with cross-validated q(2) values of 0.707 and 0.753 and CoMSIA contour maps to show the structural requirements for potent activity. These data suggest that the amide group of B13 could be replaced by thiourea, that the stereochemistry of 1,3-propandiol may not be essential for activity and that long alkyl chains increase cytotoxicity.