Nonetheless, the decrease of phospho(Ser293)-PDH
observed in Gal-dCCs after treatment with melatonin,
reinforces the idea that the anti-tumor actions of melatonin
occur at a mitochondrial level. Accordingly, our results
suggest that melatonin exerts its anticancer effects in P19
cells with an active oxidative metabolism, triggering a type
of mitochondrial cell death which is caspase-3-independent
and is probably AIF-mediated (Figure 6). These results are
in accordance with previous works developed in other types
of cancer cells such as MCF-7 [66].