Background: Considering the need for the development of new antitumor drugs, associated with the
great antitumor potential of thiophene and thiosemicarbazonic derivatives, in this work we promote molecular
hybridization approach to synthesize new compounds with increased anticancer activity.
Objective: Investigate the antitumor activity and their likely mechanisms of action of a series of N-substituted
Methods: Methods were performed in vitro (cytotoxicity, cell cycle progression, morphological analysis, mitochondrial
membrane potential evaluation and topoisomerase assay), spectroscopic (DNA interaction studies),
and in silico studies (docking and molecular modelling).
Results: Most of the compounds presented significant inhibitory activity; the NCIH-292 cell line was the most
resistant, and the HL-60 cell line was the most sensitive. The most promising compound was LNN-05 with
IC50 values ranging from 0.5 to 1.9 µg.mL-1. The in vitro studies revealed that LNN-05 was able to depolarize
(dose-dependently) the mitochondrial membrane, induceG1 phase cell cycle arrest noticeably, promote morphological
cell changes associated with apoptosis in chronic human myelocytic leukaemia (K-562) cells, and
presented no topoisomerase II inhibition. Spectroscopic UV-vis and molecular fluorescence studies showed that
LNN compounds interact with ctDNA forming supramolecular complexes. Intercalation between nitrogenous
bases was revealed through KI quenching and competitive ethidium bromide assays. Docking and Molecular
Dynamics suggested that 5-nitro-thiophene-thiosemicarbazone compounds interact against the larger DNA
groove, and corroborating the spectroscopic results, may assume an intercalating interaction mode.
Conclusion: Our findings highlight 5-nitro-thiophene-thiosemicarbazone derivatives, especially LNN-05, as a
promising new class of compounds for further studies to provide new anticancer therapies.