Fig. 2
From: Regulation of deoxynucleotide metabolism in cancer: novel mechanisms and therapeutic implications
SAMHD1 may function as a potential tumor suppressor via regulation of dNTPs. SAMHD1 is a novel mammalian dNTP triphosphohydrolase enzyme that helps in maintenance of intracellular dNTP homeostasis. SAMHD1 has been identified to be downregulated in cutaneous T-cell lymphoma and lung cancer patient samples via increased promoter DNA methylation. Downregulated SAMHD1 expression may increase the dNTP pool in these cancers resulting in enhanced DNA replication and thus tumor cell growth and proliferation. On the other hand, overexpression of SAMHD1 protein upon treatment with DNA damage-inducing agents may result in depleted dNTP pools leading to defective DNA damage repair mechanisms and thus cell cycle arrest and apoptosis