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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.

Chloroquine (CQ) is a first-choice drug against malaria and autoimmune diseases. It has been co-administered with zinc against SARS-CoV-2 and soon dismissed because of safety issues. The structural features of Zn-CQ complexes and the effect of CQ on zinc distribution in cells are poorly known. In this study, state-of-the-art computations combined with experiments were leveraged to solve the structural determinants of zinc-CQ interactions in solution and the solid state. NMR, ESI-MS, and X-ray absorption and diffraction methods were combined with ab initio molecular dynamics calculations to address the kinetic lability of this complex. Within the physiological pH range, CQ binds Zn 2+ through the quinoline ring nitrogen, forming [Zn(CQH)Cl x (H 2 O) 3- x ] (3+)- x ( x = 0, 1, 2, and 3) tetrahedral complexes. The Zn(CQH)Cl 3 species is stable at neutral pH and at high chloride concentrations typical of the extracellular medium, but metal coordination is lost at a moderately low pH as in the lysosomal lumen. The pentacoordinate complex [Zn(CQH)(H 2 O) 4 ] 3+ may exist in the absence of chloride. This in vitro / in silico approach can be extended to other metal-targeting drugs and bioinorganic systems.