Figure 7.

Copper bis(thiosemicarbazones) are highly toxic to OSCC cells in the presence of metformin. OSSC cells, untreated or treated with 10 mM metformin for 24 hours and then treated with (A) GTSM or Cu-GTSM, or (B) ATSM or Cu-ATSM for a further 48 hours were assessed by MTT assay. The non-copper-conjugated bis(thiosemicarbazones) showed relatively little toxicity with LD₅₀ values greater than 200 μM in both the presence and absence of metformin. The copper-conjugated compounds however displayed considerable toxicity to OSCC cells with similar LD₅₀ values for metformin treated-and untreated compounds for WHCO1, WHCO5, and SNO cells.