Statins markedly potentiate aminopeptidase inhibitor activity against (drug-resistant) human acute myeloid leukemia cells

Gerrit Jansen; Marjon Al; Yehuda G Assaraf; Sarah Kammerer; Johan van Meerloo; Gert J Ossenkoppele; Jacqueline Cloos; Godefridus J Peters

doi:10.20517/cdr.2023.20

Statins markedly potentiate aminopeptidase inhibitor activity against (drug-resistant) human acute myeloid leukemia cells

Cancer Drug Resist. 2023 Jul 4;6(3):430-446. doi: 10.20517/cdr.2023.20. eCollection 2023.

Authors

Gerrit Jansen¹, Marjon Al¹, Yehuda G Assaraf², Sarah Kammerer^{3

4}, Johan van Meerloo⁵, Gert J Ossenkoppele⁵, Jacqueline Cloos⁵, Godefridus J Peters^{3

6}

Affiliations

¹ Department of Rheumatology and Clinical Immunology, Amsterdam Rheumatology and immunology Center, Amsterdam University Medical Center, location VUmc, Amsterdam 1081 HV, The Netherlands.
² The Fred Wyszkowsky Cancer Research Laboratory, Faculty of Biology, The Technion-Israel Institute of Technology, Haifa 3200003, Israel.
³ Department of Medical Oncology, Amsterdam University Medical Center, location VUmc, Amsterdam 1081 HV, The Netherlands.
⁴ Institute of Biotechnology, Molecular Cell Biology, Brandenburg University of Technology Cottbus-Senftenberg, Senftenberg 01968, Germany.
⁵ Department of Hematology, Amsterdam University Medical Center, location VUmc, Amsterdam 1081 HV, The Netherlands.
⁶ Department of Biochemistry, Medical University of Gdansk, Gdansk 80-210, Poland.

Abstract

Aim: This study aimed to decipher the molecular mechanism underlying the synergistic effect of inhibitors of the mevalonate-cholesterol pathway (i.e., statins) and aminopeptidase inhibitors (APis) on APi-sensitive and -resistant acute myeloid leukemia (AML) cells. Methods: U937 cells and their sublines with low and high levels of acquired resistance to (6S)-[(R)-2-((S)-Hydroxy-hydroxycarbamoyl-methoxy-methyl)-4-methyl-pentanoylamino]-3,3 dimethyl-butyric acid cyclopentyl ester (CHR2863), an APi prodrug, served as main AML cell line models. Drug combination effects were assessed with CHR2863 and in vitro non-toxic concentrations of various statins upon cell growth inhibition, cell cycle effects, and apoptosis induction. Mechanistic studies involved analysis of Rheb prenylation required for mTOR activation. Results: A strong synergy of CHR2863 with the statins simvastatin, fluvastatin, lovastatin, and pravastatin was demonstrated in U937 cells and two CHR2863-resistant sublines. This potent synergy between simvastatin and CHR2863 was also observed with a series of other human AML cell lines (e.g., THP1, MV4-11, and KG1), but not with acute lymphocytic leukemia or multiple solid tumor cell lines. This synergistic activity was: (i) specific for APis (e.g., CHR2863 and Bestatin), rather than for other cytotoxic agents; and (ii) corroborated by enhanced induction of apoptosis and cell cycle arrest which increased the sub-G1 fraction. Consistently, statin potentiation of CHR2863 activity was abrogated by co-administration of mevalonate and/or farnesyl pyrophosphate, suggesting the involvement of protein prenylation; this was experimentally confirmed by impaired Rheb prenylation by simvastatin. Conclusion: These novel findings suggest that the combined inhibitory effect of impaired Rheb prenylation and CHR2863-dependent mTOR inhibition instigates a potent synergistic inhibition of statins and APis on human AML cells.

Keywords: Aminopeptidase; Rheb; carboxyl esterase; mTOR; mevalonate pathway; statins.