Voreloxin Hydrochloride

Voreloxin Hydrochloride is a first-in-class topoisomerase II inhibitor that intercalates DNA and induces site-selective DNA DSB, G2 arrest, and apoptosis.

Voreloxin Hydrochloride is a first-in-class topoisomerase II poison and inhibitor that intercalates DNA and induces site-selective DNA DSB, G2 arrest, and apoptosis. Voreloxin (0.1-20 µM) inhibits topoisomerase II activity and induces site-selective DNA DSB in CCRF-CEM cells. Voreloxin (0.11, 0.33, 1, 3 µM) induces G2 arrest partially through topoisomerase II in A549 lung cancer cell line. Voreloxin cytotoxic activity requires DNA intercalation. However, Voreloxin (1-9 µM) does not generate significant levels of ROS[1]. Voreloxin has potent cytotoxic activity in AML cell lines MV4-11 and HL-60, with IC50s of 95 ± 8 nM and 884 ± 114 nM, respectively. Voreloxin in combination with cytarabine shows additive or synergistic activity in acute leukemia cell lines[2]. Voreloxin is active on the primary acute myeloid leukemia (AML) with a mean LD50 of 2.3 μM. The LD50 for voreloxin in myeloid cell lines NB4 and HL-60 is 0.59 μM ± 0.25 μM. Voreloxin causes accumulation of cells in the S and G2 phases of the cell cycle and acts on topoisomerase II[3].

Voreloxin (20 mg/kg, i.v.) alone results in 80% reduction in bone marrow cellularity of CD-1 mice by administration one dose every 4 days repeated twice (q4d ×2). voreloxin at 10 mg/kg in combination with cytarabine causes ablation of the marrow, dilation of sinusoids, and infiltration of adipocytes in mice. Voreloxin (20 mg/kg, i.v.) combined with cytarabine causes a reversible decrease in myeloid and lymphoid cells in bone marrow and peripheral blood CD-1 mice. voreloxin (10 mg/kg, q4d ×2) and cytarabine in combination causes reversible neutropenia with a more modest impact on platelets CD-1 mice[2].

Reference:
[1]. Hotinski AK, et al. Vosaroxin is a novel topoisomerase-II inhibitor with efficacy in relapsed and refractory acute myeloid leukaemia. Expert Opin Pharmacother. 2015 Jun;16(9):1395-402.
[2]. Scatena CD, et al. Voreloxin, a first-in-class anticancer quinolone derivative, acts synergistically with cytarabine in vitro and induces bone marrow aplasia in vivo. Cancer Chemother Pharmacol. 2010 Oct;66(5):881-8.
[3]. Walsby EJ, et al. The topoisomerase II inhibitor voreloxin causes cell cycle arrest and apoptosis in myeloid leukemia cells and acts in synergy with cytarabine. Haematologica. 2011 Mar;96(3):393-9.