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

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.

Modulation of the megakaryoblastic Dami cell line differentiation by phosphodiesterase inhibitors and imidazo[1,2-a]pyrazine derivatives

Phosphodiesterase inhibitors have been shown to modulate cell differentiation. We have previously shown that a series of imidazo[1,2-a]pyrazine derivatives displayed inhibitory effects on phosphodiesterase isoenzymes types III. IV and V isolated from Dami cells and on Dami cell growth. In the present study we have investigated the effect of these derivatives on the expression of two differentiation markers, glycoproteins Ib and IIb/IIIa of the human megakaryoblastic leukaemic Dami cell line in comparison to those elicited by 3-isobutyl-1-methylxanthine and selective phosphodiesterase inhibitors of types 1 (8-methoxymetyl-1-methyl-3-(2-methylpropyl) xanthine), III (Milrinone), IV (RO-201724) and V (Zaprinast). Imidazo[1,2-a]pyrazine derivatives, 3-isobutyl-1-methylxanthine and selective phosphodiesterase inhibitors, except 8-methoxymethyl-1-methyl-3-(2-methylpropyl) xanthine, decreased glycoprotein Ib expression. SCA40, SCA41, SCA44 and 3-isobutyl-1-methylxanthine-but not the other compounds affected the expression of glycoprotein IIb/IIIa in a positive manner. The effects of imidazo[1,2-a]pyrazine derivatives on glycoprotein expression appeared to be related to their phosphodiesterase inhibitory potency.