Antitumor Effect of a Novel Spiro-Acridine Compound is Associated with Up-Regulation of Th1-Type Responses and Antiangiogenic Action.

Tumor cells have specific features, including angiogenesis induction, cell cycle dysregulation, and immune destruction evasion. By inducing a T helper type 2 (Th2) immune response, tumor cells may favor immune tolerance within the tumor, which allows progression of cancer growth. Drugs with potential antitumor activity are the spiro-acridines, which is a promising new class of acridine compounds. Herein, the novel spiro-acridine (E)-5'-oxo-1'-((3,4,5-trimethoxybenzylidene)amino)-1',5'-dihydro-10H-spiro[acridine-9,2'-pyrrole]-4'-carbonitrile (AMTAC-17) was synthesized and tested for antitumor effects. Toxicity evaluation was performed in mice after acute treatment (2000 mg/kg, intraperitoneally, i.p.). The Ehrlich ascites carcinoma model was used to investigate the antitumor activity of AMTAC-17 (12.5, 25, or 50 mg/kg, i.p.) after seven days of treatment. Effects on the cell cycle, angiogenesis, and inflammatory responses were investigated. LD50 (lethal dose 50%) was estimated to be higher than 5000 mg/kg. AMTAC-17 reduced the Ehrlich tumor's total viable cancer cells count and peritumoral micro-vessels density, and induced an increase in the sub-G1 peak. Additionally, there was an increase of Th1 cytokine profile levels (IL-1ß, TNF-α, and IL-12). In conclusion, the spiro-acridine compound AMTAC-17 presents low toxicity, and its in vivo antitumor effect involves modulation of the immune system to a cytotoxic Th1 profile and a reduction of tumor angiogenesis.

Synthesis and preliminary ex vivo evaluation of the spasmolytic activity of 1,3-thiazolium- and 1,3,4-thiadiazolium-5-methylthio- and 5-thioacetate derivatives.

Seven new compounds have been synthetized in satisfactory yields (51-78 %) through the treatment of mesoionic 1,3-thiazolium-5-thiolate (4a-d) and 1,3,4-thiadiazolium- 5-thiolate (10a,b) with chloroacetic acid or methyl iodide: 1,3,4-thiadiazolium-5-methylthio- (11) and 5-thioacetate (12). The structure of the title compounds was elucidated by elemental analysis, IR, (1)H and (13)C NMR spectroscopy. The newly synthesized compounds 5a, 6a, 11 and 12 were evaluated for their ex vivo spasmolytic potential on four isolated smooth muscles (rat aorta and uterus, guinea pig ileum and trachea) and compared with scopolamine. Some of the compounds exhibited potent spasmolytic activity equal to or stronger than scopolamine.