- Antimalarial N1, N3-Dialkyldioxonaphthoimidazoliums: Synthesis, Biological Activity, and Structure-activity Relationships
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Here we report the nanomolar potencies of N1,N3-dialkyldioxonaphthoimidazoliums against asexual forms of sensitive and resistant Plasmodium falciparum. Activity was dependent on the presence of the fused quinone-imidazolium entity and lipophilicity imparted by the N1/N3 alkyl residues on the scaffold. Gametocytocidal activity was also detected, with most members active at IC50 1 μM. A representative analog with good solubility, limited PAMPA permeability, and microsomal stability demonstrated oral efficacy on a humanized mouse model of P. falciparum.
- Ahenkorah, Stephen,Birkholtz, Lyn-Marie,Coertzen, Dina,Fridianto, Kevin,Go, Mei-Lin,Haynes, Richard K.,Lam, Yulin,Tan, Kevin S. W.,Tong, Jie Xin,Wittlin, Sergio
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supporting information
p. 49 - 55
(2020/02/06)
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- Dioxonaphthoimidazoliums are Potent and Selective Rogue Stem Cell Clearing Agents with SOX2-Suppressing Properties
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Pluripotent stem cells are uniquely positioned for regenerative medicine, but their clinical potential can only be realized if their tumorigenic tendencies are decoupled from their pluripotent properties. Deploying small molecules to remove remnant undifferentiated pluripotent cells, which would otherwise transform into teratomas and teratomacarcinomas, offers several advantages over non-pharmacological methods. Dioxonapthoimidazolium YM155, a survivin suppressant, induced selective and potent cell death of undifferentiated stem cells. Herein, the structural requirements for stemotoxicity were investigated and found to be closely aligned with those essential for cytotoxicity in malignant cells. There was a critical reliance on the quinone and imidazolium moieties but a lesser dependence on ring substituents, which served mainly to fine-tune activity. Several potent analogues were identified which, like YM155, suppressed survivin and decreased SOX2 in stem cells. The decrease in SOX2 would cause an imbalance in pluripotent factors that could potentially prompt cells to differentiate and hence decrease the risk of aberrant teratoma formation. As phosphorylation of the NF-κB p50 subunit was also suppressed, the crosstalk between phospho-p50, SOX2, and survivin could implicate a causal role for NF-κB signaling in mediating the stem cell clearing properties of dioxonaphthoimidazoliums.
- Ho, Si-Han Sherman,Ali, Azhar,Ng, Yi-Cheng,Lam, Kuen-Kuen Millie,Wang, Shu,Chan, Woon-Khiong,Chin, Tan-Min,Go, Mei-Lin
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supporting information
p. 1944 - 1955
(2016/10/06)
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- Antiproliferative, DNA intercalation and redox cycling activities of dioxonaphtho[2,3-d]imidazolium analogs of YM155: A structure-activity relationship study
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The anticancer agent YM155 is widely investigated as a specific survivin suppressant. More recently, YM155 was found to induce DNA damage and this has raised doubts as to whether survivin is its primary target. In an effort to assess the contribution of DNA damage to the anticancer activity of YM155, several analogs were prepared and evaluated for antiproliferative activity on malignant cells, participation in DNA intercalation and free radical generation by redox cycling. The intact positively charged scaffold was found to be essential for antiproliferative activity and intercalation but was less critical for redox cycling where the minimal requirement was a pared down bicyclic quinone. Side chain requirements at the N1 and N3 positions of the scaffold were more alike for redox cycling and intercalation than antiproliferative activity, underscoring yet again, the limited structural overlaps for these activities. Furthermore, antiproliferative activities were poorly correlated to DNA intercalation and redox cycling. Potent antiproliferative activity (IC50 9-23 nM), exceeding that of YM155, was found for a minimally substituted methyl analog AB7. Like YM155 and other dioxonaphthoimidazoliums, AB7 was a modest DNA intercalator but with weak redox cycling activity. Thus, the capacity of this scaffold to inflict direct DNA damage leading to cell death may not be significant and YM155 should not be routinely classified as a DNA damaging agent.
- Ho, Si-Han Sherman,Sim, Mei-Yi,Yee, Wei-Loong Sherman,Yang, Tianming,Yuen, Shyi-Peng John,Go, Mei-Lin
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supporting information
p. 42 - 56
(2015/10/19)
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