Discovery of IHMT-MST1-58 as a Novel, Potent, and Selective MST1 Inhibitor for the Treatment of Type 1/2 Diabetes

Development of Selective Pyrido[2,3-d]pyrimidin-7(8H)-one-Based Mammalian STE20-Like (MST3/4) Kinase Inhibitors

Mammalian STE20-like (MST) kinases 1-4 play key roles in regulating the Hippo and autophagy pathways, and their dysregulation has been implicated in cancer development. In contrast to the well-studied MST1/2, the roles of MST3/4 are less clear, in part due to the lack of potent and selective inhibitors. Here, we re-evaluated literature compounds, and used structure-guided design to optimize the p21-activated kinase (PAK) inhibitor G-5555 (8) to selectively target MST3/4. These efforts resulted in the development of MR24 (24) and MR30 (27) with good kinome-wide selectivity and high cellular potency. The distinct cellular functions of closely related MST kinases can now be elucidated with subfamily-selective chemical tool compounds using a combination of the MST1/2 inhibitor PF-06447475 (2) and the two MST3/4 inhibitors developed. We found that MST3/4-selective inhibition caused a cell-cycle arrest in the G1 phase, whereas MST1/2 inhibition resulted in accumulation of cells in the G2/M phase.

Association of MST1 in the First Trimester of Pregnancy with Gestational Diabetes Mellitus and Adverse Pregnancy Outcomes

Aim

We investigate the association of mammalian sterile line 20-like kinase 1 (MST1) in the first trimester with the risks of gestational diabetes mellitus (GDM) and adverse pregnancy outcomes.

Methods

Pregnancies were recruited during their first antenatal care visit between 8 and 12 gestational weeks. These pregnancies underwent an oral glucose tolerance test between 24 and 28 gestational weeks and were followed up until delivery. Serum MST1 levels at 8-12 gestational weeks and 24-28 gestational weeks were measured using an enzyme-linked immunosorbent assay (ELISA) kit. Logistic regression models were used to evaluate the association between MST1 levels in the first trimester and the risks of GDM and adverse pregnancy outcomes.

Results

This cohort study enrolled a total of 231 pregnancies. GDM was present in 42 (18.18%) women. Compared to the normal glucose tolerance (NGT) group, the GDM group had higher levels of FPG, HOMA-IR, and MST1 both in the first and second trimesters, but had lower HOMA-β levels only in the second trimester. Then participants were classified according to the median MST1 value in the first trimester. Incidences of GDM, composite adverse pregnancy outcomes, preterm birth, and macrosomia increased in women with higher MST1 values. Serum MST1 in the first trimester was correlated with FPG, 1hr PG, 2hr PG, and HOMA-IR, while inversely correlated with HOMA-β in the second trimester. Furthermore, after adjusting for traditional risk factors, women with higher first-trimester MST1 values had greater odds of GDM, composite adverse pregnancy outcomes, preterm birth, and macrosomia (aOR 2.276, P=0.030; aOR 2.690, P=0.003; aOR 3.210, P=0.048; aOR 5.488, P=0.010).

Conclusion

Elevated levels of MST1 in the first trimester of pregnancies are associated with increased risks of GDM and adverse pregnancy outcomes.

MST1 DOWNREGULATES TAZ TUMOUR SUPPRESSOR PROTEIN IN MULTIPLE MYELOMA AND IS A POTENTIAL THERAPEUTIC TARGET

We have previously reported that TAZ functions as a tumor suppressor in multiple myeloma. MST1 is a serine-threonine kinase upstream of the Hippo-signaling pathway that functions as a tumor suppressor in many non-haematological malignancies. However, its role in hematological malignancies, including MM is still poorly understood. In this paper, we provide evidence that MST1 expression is higher in MM, and negatively correlates with TAZ expression in both cell lines and patient samples. High MST1 expression was associated with poor clinical outcomes. Genetic or pharmacological inhibition of MST1 leads to increased TAZ expression and cell death. Importantly, MST1 inhibitors sensitizes myeloma cells to frontline antimyeloma agent-lenalidomide and dexamethasone. Taken together, our data reveals a key role for MST1 in MM pathogenesis and provide evidence to explore the therapeutic potential of using MST inhibitors to upregulate TAZ expression in MM to promote response to anticancer agents.

MST1: A future novel target for cardiac diseases

Major heart diseases pose a serious threat to human health. Finding early diagnostic markers and key therapeutic targets is an urgent scientific problem in this field. Mammalian sterile 20-like kinase 1 (MST1) is a protein kinase, and the occurrence of many heart diseases is related to the continuous activation of the MST1 gene. With the deepening of the research, the potential role of MST1 in promoting the development of heart disease has become more apparent. Therefore, to better understand the role of MST1 in the pathogenesis of heart disease, this work systematically summarizes the role of MST1 in the pathogenesis of heart disease, gives a comprehensive overview of its possible strategies in the diagnosis and treatment of heart disease, and analyzes its potential significance as a marker for the diagnosis and treatment of heart disease.