Extended Abstract

Dibenzylxanthines as PPEPCK-M Inhibitors for
Cancer Therapy †
Marc Aragó 1, Sergio Rodríguez-Arévalo 2, Petra Hyrossova 1, Juan Moreno 1, Sònia Abás 2,
Agnès Figueras 3, Belén Pérez 4, Francesc Viñals 3, María Carmen Escolano 2 and
José Carlos Perales 1,*
 1 Department of Physiological Sciences, Faculty of Medicine, University of Barcelona,
   08907 L’Hospitalet de Llobregat, Spain
 2 Department of Pharmacology and Medicinal Chemistry, Faculty of Pharmacy, and Institute of Biomedicine

   (IBUB), University of Barcelona, 08028 Barcelona, Spain
 3 Institut D'Investigació Biomèdica de Bellvitge (IDIBELL), 08907 L’Hospitalet de Llobregat, Spain

 4 Farmacologia Terapèutica i Toxicologia, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain

 * Correspondence: jperales@ub.edu
 † Presented at the 2nd Molecules Medicinal Chemistry Symposium (MMCS): Facing Novel Challenges in
   Drug Discovery, Barcelona, Spain, 15–17 May 2019.

 Published: 16 August 2019




     Phosphoenolpyruvate         carboxykinase      (PEPCK)        is    the     key      enzyme       in
gluconeogenesis/glyceroneogenesis, which catalyzes the decarboxylation of oxaloacetate to
phosphoenolpyruvate. In eukaryotes, there are two isozymes present either in the cytosol (PEPCK-
C, PCK1) or the mitochondria (PEPCK-M, PCK2). While PCK1 is found in gluconeogenic tissues
and has a very clear metabolic function, PCK2 is expressed in non-gluconeogenic cell types, where
its role remains largely unknown. For example, PCK2 is highly expressed in most cancer cells,
where it provides a growth advantage to cancer cells in nutrient-poor environments.
     A group of C-8 modified 3-alkyl-1,8-dibenzylxanthine derivatives was described as a novel
PEPCK-C inhibitor family. We hypothesized that this family of inhibitors could cross-inhibit both
PEPCK-C and PEPCK-M due to their nearly identical active center. To determine the validity of our
claim, we studied PEPCK-M target engagement using INH2—the most potent compound of the
family—and showed similar quantitate inhibitory kinetics to PEPCK-C. Therefore, we validated
PEPCK-M as a cancer target using INH2 and compared its efficacy to 3-mercaptopicolinic acid, a
classical, low potency PEPCK-C inhibitor.
     Treatment of colon and breast carcinoma cell lines with INH2 was shown to inhibit cell
proliferation, and it decreased cell survival in poor-nutrient environments. Inhibition of PEPCK-M
with INH2 also reduced colony formation in a soft agar model of anchorage-independent growth.
Finally, we tested the inhibitor in two subcutaneous xenograft models—SW-480 colon carcinoma
and MDA-MB-231 breast carcinoma. Daily dosing with 8.3 mg/kg of INH2 successfully inhibited
tumor growth with respect to the vehicle treatment group. There was no weight loss or any sign of
apparent toxicity induced by the treatment.
     Our results suggest that PEPCK-M is a valid target for cancer treatment with specific inhibitors.

                        © 2019 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access
                        article distributed under the terms and conditions of the Creative Commons Attribution (CC
                        BY) license (http://creativecommons.org/licenses/by/4.0/).




Proceedings 2019, 22, 79; doi:10.3390/proceedings2019022079                      www.mdpi.com/journal/proceedings