Design and Synthesis of Pironetin Analogue/Colchicine Hybrids and Study of Their Cytotoxic Activity and Mechanisms of Interaction with Tubulin

Abstract

We here report the synthesis of a series of 12 hybrid molecules composed of a colchicine moiety and a pironetin analogue fragment. The two fragments are connected through an ester–amide spacer of variable length. The cytotoxic activities of these compounds and their interactions with tubulin have been investigated. Relations between the structure and activity are discussed. Since the spacer is not long enough to permit a simultaneous binding of the hybrid molecules to the colchicine and pironetin sites on tubulin, a further feature investigated was whether these molecules would interact with the latter through the pironetin end (irreversible covalent binding) or through the colchicine end (reversible noncovalent binding). It has been found that binding to tubulin may take place preferentially at either of these ends depending on the length of the connecting spacer.

Design, Synthesis and Anti-proliferative Activity of Novel 5,6-Dihydro-6-alkyl-2-pyrone Analogues

“…曲 星 (Fostriecin) [1,2] 、 哥 纳 香 甲 素 (Goniothalamin) [3] 、 Cytostatin [2] 、Leptomicin B [4] 、Anguinomycin [2] 、Piro- Micheal 加成, 形成共价键 [4,8] , 在发挥作用的同时, 也 …”

Inhibitory effect of pironetin analogue/colchicine hybrids on the expression of the VEGF, hTERT and c-Myc genes

“…Thus, we incubated HT-29 cells for 48 h in the presence of DMSO (control, taken as the 100% reference) and of compounds 3, 11, 13 and colchicine, first at a concentration of 10 lM (around the IC 50 values for the hybrid compounds) and then at a concentration of 50 nM (equivalent to the IC 50 value for colchicine). 11 The results, which are depicted in Table 2, reveal that even at a 50 nM concentration, colchicine is still able to cause a marked decrease in the expression of the VEGF and hTERT genes (to more than 50% of the control value) and, most particularly, of the c-Myc gene (to 19% of the control value). It is also worth noting that the pironetin analogue 13 is essentially inactive at such a low concentration whereas hybrid 3 still retains a noticeable activity at , pironetin, colchicine and compounds 1, 3, 9, 11 and 13 (at least three measurements were performed in each case).…”

“…1). 11 These molecules were investigated for their cytotoxicity and for the mechanisms of their interaction with tubulin, the main constituent of microtubules. 12 Due to the presence of a colchicine moiety, 13 interaction of our molecules with tubulin, more specifically the b-tubulin component, was expected to occur and actually found to be the case.…”

“…14 As matter of fact, it was found that these compounds are cytotoxic and interact with tubulin at either the pironetin or the colchicine end depending on the length of the connecting spacer. 11 For anticancer therapy, potentially interesting properties should be expected from compounds that feature at least two, or better all three, of the pharmacological properties mentioned in the Introduction: cytotoxic, antiangiogenic and telomerase inhibitory activities. 15 After having measured the cytotoxicity of hybrid molecules 1-12, 16,17 we wondered whether they might possibly display valuable activities in at least one of the other two domains, antiangiogenic and telomerase inhibition ability.…”

“…The cells were incubated for 48 h in the presence of DMSO (control, taken as the 100% reference) and of each of the compounds investigated at a concentration of 5 lg/mL (lower than the IC 50 values). 11 Results are depicted in Figure 4 (hTERT gene expression) and Figure 5 (c-Myc gene expression).…”