DMAKO-20 as a New Multitarget Anticancer Prodrug Activated by the Tumor Specific CYP1B1 Enzyme

Abstract

To reduce the pervasive toxicity of natural shikonin, alkannin, and their synthetic analogues and to enhance the selectivity of these chemotherapeutics toward cancer cells, a novel 5,8-dimethyl alkannin oxime derivative (DMAKO-20) was designed, synthesized, and evaluated for its strong antitumor activity both in vitro and in vivo. It showed potent growth inhibitory effects against HCT-15, HCT-116, and K562 cells (IC50 < 1 μM), moderate antiproliferative activity toward MDA-MB-231, HepG2, PANC, Bel7402, and MGC803 cancer cells (IC50 < 10 μM), and was nontoxic to the human normal VEC and HSF cells. In vivo efficacy studies demonstrated that DMAKO-20 (10 mg/kg, i.v. on every the other day, 8 times in 14 days) resulted in 59.3% reduction in HCT-15 xenograft volume. It was as effective as the toxic antimetabolite 5-FU but revealed neither toxicity nor death in mice. The mechanistic investigations indicated that DMAKO-20 underwent the tumor-specific CYP1B1-catalyzed bioactivation to afford nitric oxide and active naphthoquinone mono-oximes, which exhibited combined anticancer effects. It was defined as a representative of the “Multi-target Anticancer Prodrugs Activated by Specific Enzymes in cancer cells”. The produced active metabolites exerted anticancer effects by the direct nucleophilic alkylation and the induction of the apoptosis of cancer cells through activation of the mitochondrial pathway. The discovery of DMAKO-20 and the illustration of its molecular mechanisms may provide a new strategy to overcome the nonselective toxicity of the current chemotherapeutics.

New Perspectives of CYP1B1 Inhibitors in the Light of Molecular Studies

“…In KLE cells (human endometrial carcinoma cell line), which overexpress CYP1B1 activity, the increased cytotoxicity of studied prodrugs was observed in comparison to cells with CYP1B1 inhibited by αnaphthoflavone (ANF) that is a potent inhibitor of CYP1 isozymes [69]. Recently discovered DMAKO-20 (5,8-dimethyl alkannin oxime derivative) is an anti-cancer prodrug activated by CYP1B1, cytotoxic to cancer cells in vitro and in vivo, while it is nontoxic to the human normal cells [70].…”

Discovery of Dimethyl Shikonin Oxime 5a, a Potent, Selective Bombesin Receptor Subtype-3 Agonist for the Treatment of Type 2 Diabetes Mellitus

“…In the nucleophilic substitution reaction between 2,2-dimethyl-1-(1,4,5,8-tetramethoxynaphthalen-2-yl) but-3-en-1-ol ( Compound-2 ) and protected bromohydrin, potassium iodine was used instead of iodine as the catalyst in order to avoid certain side reactions (Scheme ). DMAKO-00 , DMAKO-05 , and DMAKO-20 were synthesized according to the reported methods …”

“…According to the reported procedures, the title compounds were prepared as a light-yellow solid. 1 H NMR (400 MHz, DMSO- d 6 ): δ 12.11 (d, J = 11.2 Hz, 2H), 7.38 (s, 2H), 7.03 (s, 1H), 6.08–5.99 (m, 1H), 5.16–5.11 (m, 1H), 3.78 (s, 3H), 3.65 (s, 3H), 2.50–2.46 (m, 2H), 2.26 (d, J = 7.2 Hz, 2H), 2.09–1.94 (m, 1H), 1.64 (s, 3H), 1.56 (s, 3H), 0.90 (d, J = 1.3 Hz, 3H), 0.89 (d, J = 1.3 Hz, 3H).…”

“…All compounds tested were shown to be >95% pure by HPLC. 1,4,5,8-Tetramethoxy-2-naphthaldehyde as the starting material was prepared from 1,5-naphthalenediol according to the reported procedures …”

Carry-On Nitric-Oxide Luggage for Enhanced Chemotherapeutic Efficacy

“…17 However, as a gaseous radical species, it is extremely difficult to directly deliver NO in tumor therapy, 18 due to the random trajectories and rapid quenching by O 2 to NO. In this regard, more NO-donor species (NO-prodrug) have been developed to deliver NO, 19 where small-molecular-weight donors (nitrosothiols and S-nitrosylated glutathione) often suffer from short lives and ineffective distribution in vivo, 20 and metal-based NO-donors may result in unpredictable toxicity. 21 NO-donor RRx-001, which is under a Phase II clinical trial, can link to hemoglobin upon in vivo to give a prolonged circulation.…”