AK2 and neoplasm: These metabolic changes are in accordance with a previous report on tumor cell lines, in which AK2 knockdown was associated with reduced proliferation, increased glucose uptake and increased lactate production.14 Moreover, it is noteworthy that CS activity was not affected by AK2 knockdown – suggesting that the absence of AK2 expression has no effect on the number of mitochondria but did influence mitochondrial activity.