Gentamicin Targets Acid Sphingomyelinase in Cancer: The Case of the Human Gastric Cancer NCI-N87 Cells.

Elisabetta Albi,Carmela Conte,Maria Rachele Ceccarini,Katia Fettucciari,Samuela Cataldi,Michela Codini,Ivana Ferri,Federica Filomena Patria,Tommaso Beccari

doi:10.3390/ijms20184375

Elisabetta Albi, Carmela Conte + Show 7 more

Open Access

https://doi.org/10.3390/ijms20184375

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Abstract

Emerging literature implicates acid sphingomyelinase in tumor sensitivity/resistance to anticancer treatments. Gentamicin is a drug commonly used as an antimicrobial but its serendipity effects have been shown. Even though many evidences on the role of gentamicin in cancer have been reported, its mechanism of action is poorly understood. Here, we explored acid sphingomyelinase as a possible new target of gentamicin in cancer. Since gastric cancer is one of the most common cancers and represents the second cause of death in the world, we performed the study in NCI-N87 gastric cancer cell line. The effect of the drug resulted in the inhibition of cell proliferation, including a reduction of cell number and viability, in the decrease of MIB-1 proliferative index as well as in the upregulation of cyclin-dependent kinase inhibitor 1A and 1B (CDKN1A and CDKN1B), and growth arrest and DNA-damage 45A (GADD45A) genes. The cytotoxicity was apoptotic as shown by FACS analysis. Additionally, gentamicin reduced HER2 protein, indicating a minor tumor aggressiveness. To further define the involvement of sphingomyelin metabolism in the response to the drug, gene and protein expression of acid and neutral sphingomeylinase was analyzed in comparison with phosphatase and tensin homolog deleted on chromosome 10 (PTEN) and vitamin D receptor (VDR), molecules involved in cancer. Gentamicin induced a downregulation of PTEN, VDR, and neutral sphingomyelinase and a strong upregulation of acid sphingomyelinase. Of note, we identified the same upregulation of acid sphingomyelinase upon gentamicin treatment in other cancer cells and not in normal cells. These findings provide new insights into acid sphingomyelinase as therapeutic target, reinforcing studies on the potential role of gentamicin in anticancer therapy.

Highlights

Sphingomyelin (SM) is a bioactive sphingolipid recognized as an important signaling molecule in cell proliferation, differentiation, apoptosis, and cancer [1]
SM is hydrolyzed by sphingomyelinase (SMase) to produce phosphocholine and ceramide, and it is synthesized by SM-synthase by using phosphocholine from PC producing DAG
The above data provide strong evidence that neutral sphingomyelinase (nSMase) and acid sphingomyelinase (aSMase) are important regulators of cancer cell fate. Starting from these findings, we studied for the first time, the effect of GM treatment on nSMase and aSMase in NCI-N87 gastric cancer cell line, by demonstrating that the drug delays cancer cell proliferation and aggressiveness by involving aSMase

Summary

Introduction

Sphingomyelin (SM) is a bioactive sphingolipid recognized as an important signaling molecule in cell proliferation, differentiation, apoptosis, and cancer [1]. SM metabolism is a multifaceted network that involves many enzymes responsible for SM and phosphatidylcholine (PC) balance by producing second mediators such as ceramide and diacylglycerol (DAG). Both these molecules may elicit several opposite effects within the cell [2]. NSMase overexpression reduced hepatocyte proliferation [6], and its deficiency led to spontaneous liver tumor [7]. Perrotta et al (2015) highlighted the existence of an aSMase-autophagy axis whose imbalance plays a role in cancer [11]

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