Apoptotic effects of imidazo[1,2-a]pyrazine derivatives in the human Dami cell line

Synthesis and anti-tumor activities of novel [1,2,4]triazolo[1,5-a]pyrimidines

A series of novel [1,2,4]triazolo[1,5-a]pyrimidine derivatives has been designed and synthesized in order to find novel anti-tumor compounds. The structures of all the compounds were confirmed by IR, 1H-NMR, MS and elemental analysis. Their anti-tumor activities against cancer cell lines (HT-1080 and Bel-7402) were tested by the MTT method in vitro. Among them, compound 19 displayed the best anti-tumor activity with IC50 values of 12.3 microM and 6.1 microM against Bel-7402 and HT-1080 cell lines respectively.

Antiproliferative, differentiating and apoptotic effects elicited by imidazo[1,2-a]pyrazine derivatives

1. The activity of two series of imidazo[1,2-a]pyrazine derivatives on cell proliferation and differentiation and on apoptosis was examined in relation to their effects on phosphodiesterase (PDE) activity and on purinoceptors. 2. In the first series SC-18 and SC-51 inhibited mitogen-induced 3H-thymidine incorporation in human lymphocytes. 3. The compounds of the new series PAB13, PAB23 and SCA40 inhibited the proliferation of the HEL cell line. 4. Nine imidazo[1,2-a]pyrazine derivatives of the new series have been studied on the Dami cell proliferation. SCA41 and SCA44 inhibited cell growth, SCA40 and PAB40 were moderately effective, whereas PAB12 and PAB30 were devoid of effect. The antiproliferative effects of these six non-cytotoxic compounds could not be related to their action on PDE or on purinoceptors, but rather to their lipophilicity. Conversely, for PAB13, PAB15, and PAB23, the decrease in cell number was related to their cytotoxic and apoptotic effects through their cAMP-increasing and PDE-inhibitory potency, but unrelated to an effect on purinoceptors. 5. Imidazo[1,2-a]pyrazine derivatives decreased the expression of Glycoprotein (GP)Ib in Dami cells while some of them enhanced that of GPIIb/IIIa. These effects appeared to involve inhibition of both cAMP- and cGMP-PDE. 6. These studies demonstrate the potential interest of imidazo[1,2-a]pyrazine derivatives in the query of novel anticancer drugs.

Antiproliferative effects of imidazo[1,2-a]pyrazine derivatives on the Dami cell line

Since cyclic 3',5'-adenosine monophosphate (cAMP) is involved in cell proliferation and as previous data showed that imidazo[1,2-alpha]pyrazine derivatives (PAB12, PAB30, PAB40, SCA40, SCA41, and SCA44) inhibited cAMP breakdown by a phosphodiesterase (PDE)-inhibitory effect, the aim of the present study was to investigate the effects of these derivatives on proliferation of the Dami cell line in relation with their actions on cAMP content and on PDE isoenzymes isolated from Dami cells. SCA41 and SCA44 inhibited cell growth in a dose-dependent manner, while SCA40 and PAB40 induced a weak inhibition. Growth inhibitions were 40%, 91%, and 60% for SCA41, SCA44 (at 100 microM), and IBMX (at 100 microM), respectively, and could not be related to their effects on cAMP levels. In addition, although all compounds potentiated cAMP formation by prostaglandin E1 (PGE1), no potentiations were observed when the antiproliferative effects of SCA41 and SCA44 were considered. Investigation of derivatives on PDE isoenzymes III, IV, and V indicated non-selective PDE inhibitory effects for SCA41 and SCA44, while SCA40 elicited preferences for type III, and PAB30 and PAB40 preferences for type IV isoenzymes. These effects could not totally explain the antiproliferative activity of the derivatives. The activation of P2 purinoceptors by imidazo[1,2-a]pyrazine did not lead to their antiproliferative effects. Thus, the mechanism of the antiproliferative effects of the compounds remains to be determined. It does, however, depend on the chemical substitutions of the imidazo[1,2-a]pyrazine skeleton and in particular on the 2-carbonitrile presence and the length of the 8-aminoaliphatic group.