Synthesis and structure-activity relationships of phenylenebis(methylene)-linked bis-azamacrocycles that inhibit HIV-1 and HIV-2 replication by antagonism of the chemokine receptor CXCR4.
Bis-tetraazamacrocycles such as the bicyclam AMD3100 are a class of potent and selective anti-HIV-1 and HIV-2 agents that inhibit virus replication by binding to the chemokine receptor CXCR4, the co-receptor for entry of X4 viruses. With the aim of optimizing the anti-HIV-1 and HIV-2 activity of bis-azamacrocycles, a series of analogues were synthesized which contain neutral heteroatom (oxygen, sulfur) or heteroaromatic (of lower pK(a) than a secondary amine) replacements for the amino groups of AMD3100. The introduction of one or more heteroatoms such as oxygen or sulfur into the macrocyclic ring of p-phenylenebis(methylene)-linked dimers (to give N(3)X or N(2)X(2) bis-macrocycles) gave analogues with substantially reduced anti-HIV-1 (III(B)) and anti-HIV-2 (ROD) potency. In addition, the bis-sulfur analogue was also markedly more cytotoxic to MT-4 cells. However, bis-tetraazamacrocycles featuring a single pyridine group incorporated within the macrocyclic framework exhibited anti-HIV-1 and HIV-2 potency comparable to that of their saturated, aliphatic counterparts. The p-phenylenebis(methylene)-linked dimer of the py[14]aneN(4) macrocycle inhibited HIV-1 replication at a 50% effective concentration (EC(50)) of 0.5 microM while remaining nontoxic to MT-4 cells at concentrations approaching 200 microM. A series of analogues containing macrocyclic heteroaromatic groups of varying pK(a) were also synthesized, and their ability to inhibit HIV replication was evaluated. Replacing the pyridine moiety of the py[14]aneN(4) macrocyclic ring with pyrazine or pyridine groups substituted in the 4-position (with electron-withdrawing or -donating groups) either reduced antiviral potency or increased cytotoxicity to MT-4 cells. Finally, we synthesized a series of analogues in which the ring size of the bis-pyridyl macrocycles was varied between 12 and 16 members per ring including the py[iso-14]aneN(4) ring system, an isomer of the py[14]aneN(4) macrocycle. The p-phenylenebis(methylene)-linked dimer of the py[iso-14]aneN(4) (AMD3329) displayed the highest antiviral activity of the bis-azamacrocyclic analogues reported to date, exhibiting EC(50)'s against the cytopathic effects of HIV-1 and HIV-2 replication of 0.8 and 1.6 nM, respectively, that is, about 3-5-fold lower than the EC(50) of AMD3100. AMD3329 also inhibited the binding of a specific CXCR4 mAb and the Ca(2+) flux induced by SDF-1alpha, the natural ligand for CXCR4, more potently than AMD3100. Furthermore, AMD3329 also interfered with virus-induced syncytium formation at an EC(50) of 12 nM.
Bridger
G J
GJ
AnorMED Inc., 200-20353 64(th) Avenue, Langley, British Columbia V2Y 1N5, Canada. gbridger@anormed.com
Skerlj
R T
RT
Padmanabhan
S
S
Martellucci
S A
SA
Henson
G W
GW
Struyf
S
S
Witvrouw
M
M
Schols
D
D
De Clercq
E
E
D019380:Anti-HIV Agents / Q000737:chemistry* / Q000494:pharmacology*; D001596:Benzylamines; D002118:Calcium / Q000378:metabolism; D002460:Cell Line; D000080027:Cyclams; D016257:Fura-2 / Q000378:metabolism; D015497:HIV-1 / Q000187:drug effects / Q000502:physiology*; D015498:HIV-2 / Q000187:drug effects / Q000502:physiology*; D006571:Heterocyclic Compounds / Q000737:chemistry* / Q000494:pharmacology*; D006574:Heterocyclic Compounds, 2-Ring / Q000138:chemical synthesis* / Q000494:pharmacology*; D006801:Humans; D008956:Models, Chemical; D019718:Receptors, CXCR4 / Q000037:antagonists & inhibitors*; D013329:Structure-Activity Relationship; D014407:Tumor Cells, Cultured; D014779:Virus Replication / Q000187:drug effects*
D019380:Anti-HIV Agents; D001596:Benzylamines; D000080027:Cyclams; D006571:Heterocyclic Compounds; D006574:Heterocyclic Compounds, 2-Ring; D019718:Receptors, CXCR4; C088327:plerixafor; D002118:Calcium; D016257:Fura-2