Quinoline based mono- and bis-(thio) carbohydrazones: synthesis, anticancer activity in 2D and 3D cancer and cancer stem cell models

A comparative study of antitumor activity of mono- and bis-quinoline based (thio) carbohydrazones was investigated by a series of tests on two human malignant cell lines: acute monocytic leukemia (THP-1) and pancreatic adenocarcinoma cancer stem cells (AsPC-1). Thiocarbohydrazones (TCHs) revealed superior pro-apoptotic activity over carbohydrazones (CHs) on both tested cell phenotypes, also displaying multi-target profile activities. Programmed cell death triggered by TCHs was partially caspase-dependent, mainly caspase-8 related. Activity against cancer stem cells (CSCs) was evaluated on 2D monolayers and 3D spheroidal models, where two out of three tested bis-TCHs successfully stimulated apoptosis accompanied by a reduction in size of treated spheres. Additionally, all bis-TCHs induced significant decrease in percentage of CD44-expressing AsPC-1 cells that indicate on their ability to induce reprogramming of CSC phenotype. Current results highly support further assessment of bis-TCHs in order to specify their specific targets in cancer cells and particularly in the CSCs subpopulation.