Synthesis and anti-staphylococcal activity of novel bacterial topoisomerase inhibitors with a 5-amino-1,3-dioxane linker moiety.

Novel bacterial type II topoisomerase inhibitors (NBTIs) constitute a promising new class of antibacterial agents. We report a series of NBTIs with potent anti-staphylococcal activity and diminished hERG inhibition. Dioxane-linked compound 9 demonstrated MICs ≤1 μg/mL against both methicillin-susceptible (MSSA) and -resistant Staphylococcus aureus (MRSA), accompanied by reduced hERG inhibition as compared to cyclohexane- or piperidine-linked analogs.

Synthesis and antiproliferative activity of derivatives of the phyllanthusmin class of arylnaphthalene lignan lactones.

A series of arylnaphthalene lignan lactones based on the structure of the phyllanthusmins, a class of potent natural products possessing diphyllin as the aglycone, has been synthesized and screened for activity against multiple cancer cell lines. SAR exploration was performed on both the carbohydrate and lactone moieties of this structural class. These studies have revealed the importance of functionalization of the carbohydrate hydroxy groups with both acetylated and methylated analogues showing increased potency relative to those with unsubstituted sugar moieties.

The Novel C-terminal Truncated 90-kDa Isoform of Topoisomerase II (TOP2/90) Is a Determinant of Etoposide Resistance in K562 Leukemia Cells via Heterodimerization with the TOP2/170 Isoform.

DNA topoisomerase II (170 kDa, TOP2/170) is essential in proliferating cells by resolving DNA topological entanglements during chromosome condensation, replication, and segregation. We previously characterized a C-terminally truncated isoform (TOP2/90), detectable in human leukemia K562 cells but more abundantly expressed in a clonal subline, K/VP.5, with acquired resistance to the anticancer agent etoposide.

Capsicodendrin from Cinnamosma fragrans Exhibits Antiproliferative and Cytotoxic Activity in Human Leukemia Cells: Modulation by Glutathione.

Capsicodendrin (CPCD, 1), an epimeric mixture of a dimeric drimane-type sesquiterpene, is one of the major compounds present in the three endemic species of Madagascan traditional chemopreventive plants: Cinnamosma species ( C. fragrans, C. macrocarpa, and C.

Alternative RNA Processing of Topoisomerase IIα in Etoposide-Resistant Human Leukemia K562 Cells: Intron Retention Results in a Novel C-Terminal Truncated 90-kDa Isoform.

DNA topoisomerase IIα (TOP2α) is a prominent target for anticancer drugs whose clinical efficacy is often limited by chemoresistance. Using antibody specific for the N-terminal of TOP2α, immunoassays indicated the existence of two TOP2α isoforms, 170 and 90 kDa, present in K562 leukemia cells and in an acquired etoposide (VP-16)-resistant clone (K/VP.5).

Mechanisms of Action and Reduced Cardiotoxicity of Pixantrone; a Topoisomerase II Targeting Agent with Cellular Selectivity for the Topoisomerase IIα Isoform.

Pixantrone is a new noncardiotoxic aza-anthracenedione anticancer drug structurally related to anthracyclines and anthracenediones, such as doxorubicin and mitoxantrone. Pixantrone is approved in the European Union for the treatment of relapsed or refractory aggressive B cell non-Hodgkin lymphoma. This study was undertaken to investigate both the mechanism(s) of its anticancer activity and its relative lack of cardiotoxicity.