Approaches to reduce succinate accumulation by restoration of succinate dehydrogenase activity in cultured adrenal cells.

The rare human neuroendocrine tumors pheochromocytoma and paraganglioma (PPGL) can result from loss of mitochondrial succinate dehydrogenase. The resulting succinate accumulation is tumorigenic in certain neuroendocrine cells. Here, we explore two theoretical approaches to mitigate tumorigenic succinate accumulation in a cell culture model of PPGL. We first study a gene replacement strategy using transposition technology, and conclude that many of the changes in mitochondrial morphology, oxidative cell metabolism and succinate accumulation can be reversed by this process. We then investigate whether riboflavin supplementation has the potential to rescue succinate dehydrogenase activity in the intact SDHA catalytic subunit to suppress succinate accumulation even in the absence of SDHB. We show that this latter strategy is not successful.