Synthesis and Biological Activity of a New Indenoisoquinoline Copper Derivative as a Topoisomerase I Inhibitor

Topoisomerases are interesting targets in cancer chemotherapy. Here, we describe the design and synthesis of a novel copper(II) indenoisoquinoline complex, WN198. The new organometallic compound exhibits a cytotoxic effect on five adenocarcinoma cell lines (MCF-7, MDA-MB-231, HeLa, HT-29, and DU-145) with the lowest IC50 (0.37 ± 0.04 μM) for the triple-negative MDA-MB-231 breast cancer cell line. Below 5 µM, WN198 was ineffective on non-tumorigenic epithelial breast MCF-10A cells and Xenopus oocyte G2/M transition or embryonic development. Moreover, cancer cell lines showed autophagy markers including Beclin-1 accumulation and LC3-II formation. The DNA interaction of this new compound was evaluated and the dose-dependent topoisomerase I activity starting at 1 μM was confirmed using in vitro tests and has intercalation properties into DNA shown by melting curves and fluorescence measurements. Molecular modeling showed that the main interaction occurs with the aromatic ring but copper stabilizes the molecule before binding and so can putatively increase the potency as well. In this way, copper-derived indenoisoquinoline topoisomerase I inhibitor WN198 is a promising antitumorigenic agent for the development of future DNA-damaging treatments.

A Novel Copper(II) Indenoisoquinoline Complex Inhibits Topoisomerase I, Induces G2 Phase Arrest, and Autophagy in Three Adenocarcinomas

Topoisomerases, targets of inhibitors used in chemotherapy, induce DNA breaks accumulation leading to cancer cell death. A newly synthesized copper(II) indenoisoquinoline complex WN197 exhibits a cytotoxic effect below 0.5 µM, on MDA-MB-231, HeLa, and HT-29 cells. At low doses, WN197 inhibits topoisomerase I. At higher doses, it inhibits topoisomerase IIα and IIβ, and displays DNA intercalation properties. DNA damage is detected by the presence of γH2AX. The activation of the DNA Damage Response (DDR) occurs through the phosphorylation of ATM/ATR, Chk1/2 kinases, and the increase of p21, a p53 target. WN197 induces a G2 phase arrest characterized by the unphosphorylated form of histone H3, the accumulation of phosphorylated Cdk1, and an association of Cdc25C with 14.3.3. Cancer cells die by autophagy with Beclin-1 accumulation, LC3-II formation, p62 degradation, and RAPTOR phosphorylation in the mTOR complex. Finally, WN197 by inhibiting topoisomerase I at low concentration with high efficiency is a promising agent for the development of future DNA damaging chemotherapies.

In situ generation of dihydropyridine for the enantioselective transfer hydrogenation of 1,4-benzoxazines

A new strategy for the enantioselective transfer hydrogenation of benzoxazines involving an in situ generation of Hantzsch ester has been developed. Dihydroadducts were isolated in good yields (75–99%) and enantioselectivities (89–96% ee).

Enantioselective transfer hydrogenation, a key step for the synthesis of 3-aminotetrahydroquinolines

An enantioselective transfer hydrogenation has been successfully achieved to furnish 3-aminotetrahydroquinolines. The reaction was conducted in the presence of Hantzsch dihydropyridine and a catalytic amount of chiral phosphoric acid under mild conditions.

Catalytic one-pot microwave assisted synthesis of 4-azapodophyllotoxin derivatives and rational design of experiment

A catalytic one-pot microwave assisted synthesis of 4-azapodophyllotoxin has been described. Rational design of experiment has been used to obtain the reaction yield.

In situ generation of ammonia for the copper-catalyzed synthesis of primary aminoquinolines

Primary aminoquinolines were synthesized from iodoquinolines in the presence of a copper(i) iodide catalyst and formamide as both solvent and source of ammonia generated in situ.

Synthesis and antimycobacterial activity of ferrocenyl ethambutol analogues and ferrocenyl diamines

A new series of ferrocenyl diamino alcohols and diamines were synthesized and their inhibitory potencies were probed with Mycobacterium tuberculosis. Interestingly, ferrocenyl diamines 6a and b display significant activities against M. tuberculosis H37Rv.

Synthesis and chloroquine-enhancing activity of Na-deacetyl-ferrocenoyl-strychnobrasiline

Several strychnobrasiline derivatives have been synthesized to overcome the lack of in vivo reversal activity of the parent compound. In the present study, N(a)-deacetyl-ferrocenoyl-strychnobrasiline was synthesized by condensing N(a)-deacetyl-strychnobrasiline with ferrocenic acid previously treated with oxalyl chloride. While the in vitro antiplasmodial activity of the test compound (IC(50)=4.83 microg/mL) was increased 15-fold compared to that of strychnobrasiline, and the in vitro enhancing activity was found to be similar to that of the parent compound, the compound was devoid of any in vivo potentiating effect, and an antagonistic effect was even observed at higher doses. Based on the overall results on the hemisynthesis of strychnobrasiline derivatives for better reversal activity, this strategy has appeared to be of little value for useful drugs.