In Vitro and In Vivo Pharmacological Profiles of DS-1211, a Novel Potent, Selective, and Orally Bioavailable Tissue-Nonspecific Alkaline Phosphatase Inhibitor

Do alkaline phosphatases have great potential in the diagnosis, prognosis, and treatment of tumors?

Alkaline phosphatase (ALP) is a group of enzymes that catalyze hydrolysis of phosphate esters at an alkaline pH, resulting in the generation of inorganic phosphate. These enzymes are widely distributed, and their activity is found in various tissues including bone, liver, intestine, and placenta. However, abnormalities in ALP expression and activity have been observed in certain types of cancer. In some cases, elevated serum levels of ALP are observed in patients with liver and bone metastasis. In other cases, increased levels of ALP have been observed in patients with pancreatic and lung cancer. On the other hand, low expression of ALP has also been associated with poor prognosis in patients with certain types of tumors, including colorectal cancer (CRC), breast cancer, and non-small cell lung cancer (NSCLC). In these cases, low ALP activity may be associated with decreased differentiation of cancer cells and increased cancer cell proliferation. Overall, the role of ALP in cancer is complex and context-dependent. This article reviews application progress of ALP in cancer, and we hypothesize that ALP might be a potential tumor biomarker, combined detection of aspartate aminotransferase (AST)/alanine aminotransferase (ALT), bone-specific alkaline phosphatase (BSAP), carbohydrate antigen 19-9 (CA 19-9), lactate dehydrogenase (LDH) and ALP isozymes levels can be used for more accurate diagnosis of a particular tumor. Further research is needed to better understand the mechanisms underlying ALP dysregulation in cancer and to identify potential therapeutic targets.

Anticalcification effects of DS-1211 in pseudoxanthoma elasticum mouse models and the role of tissue-nonspecific alkaline phosphatase in ABCC6-deficient ectopic calcification

Pseudoxanthoma elasticum (PXE) is a multisystem, genetic, ectopic mineralization disorder with no effective treatment. Inhibition of tissue-nonspecific alkaline phosphatase (TNAP) may prevent ectopic soft tissue calcification by increasing endogenous pyrophosphate (PPi). This study evaluated the anticalcification effects of DS-1211, an orally administered, potent, and highly selective small molecule TNAP inhibitor, in mouse models of PXE. Calcium content in vibrissae was measured in KK/HlJ and ABCC6^-/- mice after DS-1211 administration for 13-14 weeks. Pharmacokinetic and pharmacodynamic effects of DS-1211 were evaluated, including plasma alkaline phosphatase (ALP) activity and biomarker changes in PPi and pyridoxal-phosphate (PLP). Anticalcification effects of DS-1211 through TNAP inhibition were further evaluated in ABCC6^-/- mice with genetically reduced TNAP activity, ABCC6^-/-/TNAP^+/+ and ABCC6^-/-/TNAP^+/-. In KK/HlJ and ABCC6^-/- mouse models, DS-1211 inhibited plasma ALP activity in a dose-dependent manner and prevented progression of ectopic calcification compared with vehicle-treated mice. Plasma PPi and PLP increased dose-dependently with DS-1211 in ABCC6^-/- mice. Mice with ABCC6^-/-/TNAP^+/- phenotype had significantly less calcification and higher plasma PPi and PLP than ABCC6^-/-/TNAP^+/+ mice. TNAP plays an active role in pathomechanistic pathways of dysregulated calcification, demonstrated by reduced ectopic calcification in mice with lower TNAP activity. DS-1211 may be a potential therapeutic drug for PXE.