Structural re-positioning, in silico molecular modelling, oxidative degradation, and biological screening of linagliptin as adenosine 3 receptor (ADORA3) modulators targeting hepatocellular carcinoma

Abstract

Chemical entities with structural diversity were introduced as candidates targeting adenosine receptor with different clinical activities, containing 3,7-dihydro-1H-purine-2,6-dione, especially adenosine 3 receptors (ADORA3). Our initial approach started with pharmacophore screening of ADORA3 modulators; to choose linagliptin (LIN), approved anti-diabetic drug as Dipeptidyl peptidase-4 inhibitors, to be studied for its modulating effect towards ADORA3. This was followed by generation, purification, analytical method development, and structural elucidation of oxidative degraded product (DEG). Both of LIN and DEG showed inhibitory profile against hepatocellular carcinoma cell lines with induction of apoptosis at G2/M phase with increase in caspase-3 levels, accompanied by a downregulation in gene and protein expression levels of ADORA3 with a subsequent increase in cAMP. Quantitative in vitro assessment of LIN binding affinity against ADORA3 was also performed to exhibit inhibitory profile at Ki of 37.7 nM. In silico molecular modelling showing binding affinity of LIN and DEG towards ADORA3 was conducted.

KEYWORDS:

• Drug repositioning
• adenosine 3 receptor
• linagliptin
• hepatocellular carcinoma

Acknowledgements

The authors would like to thank OpenEye molecular modelling software for supporting an academic license.

Disclosure statement

No potential conflict of interest was reported by the authors.

The authors have equally contributed for this work. Both B.M.A. & M.S.A. provided the experimental materials, reviewed the literature, performed the DEG preparation, optimized the reaction conditions, and finalized the structure elucidation using FTIR and NMR. B.M.A. performed HPLC-DAD and LC-MS/MS experiments, where MSA conducted the purification steps and virtual screening/simulation studies. YMA conducted the whole in vitro studies and interpreted the whole pharmacological data. Finally, all the authors wrote, reviewed, and approved the manuscript including figures and tables.

Additional information

Funding

This research was funded by The British University in Egypt, under Young Investigator Research Grant Program (YIRG), grant number [YIRG-2016–01] on 1 October 2016, granted to Dr. Mahmoud Salama Ahmed and Center of Drug Research and Discovery (CDRD) at BUE.