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Pancreatic cancer, with its increasing incidence and lowest 5-year survival rate, is predicted to become the second leading cause of cancer deaths by 2030. Current clinical trials have shown limited improvement, highlighting the need for new therapies. The sigma-2 receptor (S2R), with roles in tumor progression, is a target for novel thiosemicarbazones (TSCs). FA4 has shown potent activity against pancreatic cancer in vivo . We synthesized complexes of FA4 with Cu(II) and Pt(II), and compared their efficacy with complexes of the non-S2R-targeting TSC 1 . TSC-Cu exhibited over 50-fold higher in vitro cytotoxicity than TSCs-Pt, which was less active than TSCs. FA4 -Cu induced apoptotic cell death via ER and mitochondrial stress showing more potent activity than FA4 . This in vitro effect was replicated in the preclinical PANC-1 model, where FA4 -Cu was more potent than FA4 , 1 , and 1 -Cu. These results support further exploration of FA4 -Cu as a potential therapy for pancreatic cancer.

Background: Multifunctional thiosemicarbazones (TSCs) able to bind sigma receptors and chelate metals are considered as a promising avenue for the treatment of pancreatic cancer due to the encouraging results obtained on in vitro and in vivo models. Here, we assessed the biochemical mechanism of these TSCs also on lung (A549) and breast (MCF7) cancer cells., Methods: The density of sigma-2 receptors in normal (BEAS-2B and MCF10A) and in lung and breast (A549 and MCF7) cancer cells was evaluated by flow cytometry. In these cells, cytotoxicity (MTT assay) and activation of ER- and mitochondria-dependent cell death pathways (by spectrofluorimetric assays to measure Caspases 3/7/9; qRT-PCR detection of GRP78, ATF6, IRE1, PERK; MitoSOX, DCFDA-AM and JC-1 staining), induced by the TSCs FA4, MLP44, PS3 and ACThio1, were evaluated., Results: FA4 and PS3 exerted more potent cytotoxicity than MLP44 and ACThio1 in all cancer cell lines, where the density of sigma-2 receptors was higher than in normal cells. Remarkably, FA4 promoted ER- and mitochondria-dependent cell death pathways in both cell models, whereas the other TSCs had variable, cell-dependent effects on the activation of the two proapoptotic pathways., Conclusions: Our data suggest that FA4 is a promising compound that deserves to be further studied for lung and breast cancer treatment. However, the other multifunctional TSCs also hold promise for the development of therapies towards a personalized medicine approach. Indeed, the presence of the sigma-2 receptor-targeting moiety would lead to a more specific tumor delivery embracing the characteristics of individual tumor types., (© 2023. The Author(s).)