bims-polyam 2024-04-21 papers

Issue of 2024–04–21
two papers selected by
Sebastian J. Hofer, University of Graz

Int J Med Sci. 2024 ;21(5): 904-913

Natural Product Quercetin-3-methyl ether Promotes Colorectal Cancer Cell Apoptosis by Downregulating Intracellular Polyamine Signaling.

Jincheng Zeng, Yuancheng Zhang, Yuming Fang, Jiachun Lian, Hailiang Zhang, Shaobing Zhang, Bihua Lin, Ziyu Ye, Caihong Li, Xianxiu Qiu, Yanfang Liang.

Dysregulation of cellular metabolism is a key marker of cancer, and it is suggested that metabolism should be considered as a targeted weakness of colorectal cancer. Increased polyamine metabolism is a common metabolic change in tumors. Thus, targeting polyamine metabolism for anticancer therapy, particularly polyamine blockade therapy, has gradually become a hot topic. Quercetin-3-methyl ether is a natural compound existed in various plants with diverse biological activities like antioxidant and antiaging. Here, we reported that Quercetin-3-methyl ether inhibits colorectal cancer cell viability, and promotes apoptosis in a dose-dependent and time-dependent manner. Intriguingly, the polyamine levels, including spermidine and spermine, in colorectal cancer cells were reduced upon treatment of Quercetin-3-methyl ether. This is likely resulted from the downregulation of SMOX, a key enzyme in polyamine metabolism that catalyzes the oxidation of spermine to spermidine. These findings suggest Quercetin-3-methyl ether decreases cellular polyamine level by suppressing SMOX expression, thereby inducing colorectal cancer cell apoptosis. Our results also reveal a correlation between the anti-tumor activity of Quercetin-3-methyl ether and the polyamine metabolism modulation, which may provide new insights into a better understanding of the pharmacological activity of Quercetin-3-methyl ether and how it reprograms cellular polyamine metabolism.

Keywords: cell apoptosis; colorectal cancer cell; natural product; quercetin-3-methyl ether

DOI: https://doi.org/10.7150/ijms.93903

Cardiovasc Res. 2024 Apr 16. pii: cvae068. [Epub ahead of print]

ATP13A3 variants promote pulmonary arterial hypertension by disrupting polyamine transport.

Bin Liu, Mujahid Azfar, Ekaterina Legchenko, James A West, Shaun Martin, Chris Van den Haute, Veerle Baekelandt, John Wharton, Luke Howard, Martin R Wilkins, Peter Vangheluwe, Nicholas W Morrell, Paul D Upton.

AIMS: Potential loss-of-function variants of ATP13A3, the gene encoding a P5B-type transport ATPase of undefined function, were recently identified in pulmonary arterial hypertension (PAH) patients. ATP13A3 is implicated in polyamine transport but its function has not been fully elucidated. Here, we sought to determine the biological function of ATP13A3 in vascular endothelial cells and how PAH-associated variants may contribute to disease pathogenesis.
METHODS AND RESULTS: We studied the impact of ATP13A3 deficiency and overexpression in endothelial cell (EC) models (human pulmonary ECs, blood outgrowth ECs (BOECs) and HMEC-1 cells), including a PAH patient-derived BOEC line harbouring an ATP13A3 variant (LK726X). We also generated mice harbouring an Atp13a3 variant analogous to a human disease-associated variant to establish whether these mice develop PAH.ATP13A3 localised to the recycling endosomes of human ECs. Knockdown of ATP13A3 in ECs generally reduced the basal polyamine content and altered the expression of enzymes involved in polyamine metabolism. Conversely, overexpression of wild-type ATP13A3 increased polyamine uptake. Functionally, loss of ATP13A3 was associated with reduced EC proliferation, increased apoptosis in serum starvation and increased monolayer permeability to thrombin. Assessment of five PAH-associated missense ATP13A3 variants (L675V, M850I, V855M, R858H, L956P) confirmed loss-of-function phenotypes represented by impaired polyamine transport and dysregulated EC function. Furthermore, mice carrying a heterozygous germ-line Atp13a3 frameshift variant representing a human variant spontaneously developed a PAH phenotype, with increased pulmonary pressures, right ventricular remodelling and muscularisation of pulmonary vessels.
CONCLUSION: We identify ATP13A3 as a polyamine transporter controlling polyamine homeostasis in ECs, deficiency of which leads to EC dysfunction and predisposes to PAH. This suggests a need for targeted therapies to alleviate the imbalances in polyamine homeostasis and EC dysfunction in PAH.

DOI: https://doi.org/10.1093/cvr/cvae068