Protein tyrosine phosphatase 1B (PTP1B) inhibitors as potential anti-diabetes agents: patent review (2015-2018)

Turn and Face the Strange: A New View on Phosphatases

Phosphorylation as a post-translational modification is critical for cellular homeostasis. Kinases and phosphatases regulate phosphorylation levels by adding or removing, respectively, a phosphate group from proteins or other biomolecules. Imbalances in phosphorylation levels are involved in a multitude of diseases. Phosphatases are often thought of as the black sheep, the strangers, of phosphorylation-mediated signal transduction, particularly when it comes to drug discovery and development. This is due to past difficulties to study them and unsuccessful attempts to target them; however, phosphatases have regained strong attention and are actively pursued now in clinical trials. By giving examples for current hot topics in phosphatase biology and for new approaches to target them, it is illustrated here how and why phosphatases made their comeback, and what is envisioned to come in the future.

Identification of protein tyrosine phosphatase 1B (PTP1B) inhibitors through De Novo Evoluton, synthesis, biological evaluation and molecular dynamics simulation

Protein tyrosine phosphatase 1B (PTP1B) is a widely expressed 50 kDa enzyme and the first intracellular PTP to be purified from human placental tissue. It has been proved that protein tyrosine phosphatase 1B played a significant role in the negative regulation of insulin signaling pathway and overexpression of PTP1B could lead to the decrease of insulin resistance. Therefore PTP1B has emerged as a novel promising therapeutic target for the treatment of type-2 diabetes mellitus. Computer aided drug design (CADD), chemical synthesis and biological activity assay resulted in the identification of a novel potent PTP1B inhibitor, compound 1a, which shared an IC₅₀ value of 4.46 μM. Finally, the analysis of molecular dynamics simulation provided the theoretical basis for favorable activity of compound 1a.

Protein Tyrosine Phosphatase 1B Inhibitory Iridoids from Psydrax subcordata

Phytochemical investigation of the leaves and bark of Psydrax subcordata has led to the isolation of six new iridoids, subcordatanols I-V (1-4 and 6) and 1-O-methylcrescentin I (5), along with two known analogues (7 and 8). Among them, subcordatanol I (1) is the first example of a 3,8-monoepoxy-iridoid featuring a caged 2-oxa-bicyclo[3.2.1]octane core. The absolute stereochemistry at C-4 of 3, 4, and 6 was established through their acid-catalyzed reaction products subcordatalactones A (3a), B (4a), and C (6a), respectively. Subcordatanols I (1) and II (2), as well as subcordatalactones A (3a) and B (4a), displayed inhibitory activity against protein tyrosine phosphatase 1B (PTP1B). Enzyme kinetic studies indicated that 3a and 4a are competitive inhibitors. A molecular docking study is also reported.

Docosahexaenoic Acid Inhibits PTP1B Phosphatase and the Viability of MCF-7 Breast Cancer Cells

BACKGROUND

Docosahexaenoic acid (DHA) is an essential polyunsaturated fatty acid compound present in deep water fishes and dietary supplements, with a wide spectrum of potential health benefits, ranging from neurological to anti-inflammatory.

METHODS

Due to the fact that DHA is considered a breast cancer risk reducer, we examined the impact of DHA on MCF-7 breast cancer cells' viability and its inhibitory properties on protein tyrosine phosphatase 1B (PTP1B), a pro-oncogenic phosphatase.

RESULTS

We found that DHA is able to lower both the enzymatic activity of PTP1B phosphatase and the viability of MCF-7 breast cancer cells. We showed that unsaturated DHA possesses a significantly higher inhibitory activity toward PTP1B in comparison to similar fatty acids. We also performed a computational analysis of DHA binding to PTP1B and discovered that it is able to bind to an allosteric binding site.

CONCLUSIONS

Utilizing both a recombinant enzyme and cellular models, we demonstrated that DHA can be considered a potential pharmacological agent for the prevention of breast cancer.