Anticancer activity and metabolic profile alterations by ortho-topolin riboside in in vitro and in vivo models of non-small cell lung cancer

Lung cancer has the highest incidence and mortality rates among all types of cancer worldwide, and 80%-85% of patients with lung cancer are diagnosed with non-small cell lung cancer (NSCLC), which has 5-year survival rate of only 5% at advanced stages. Development of new therapeutic agents and strategies is required to enhance the treatment efficiency in patients with NSCLC. Metabolic alterations and anticancer effects of plant hormones and their derivatives have not been investigated in NSCLC in vitro and in vivo. The present study investigated the cytotoxic effects of 11 plant hormones and their derivatives against NSCLC cell lines; ortho-topolin riboside (oTR) showed the highest cytotoxicity among all tested compounds against NSCLC cells. Alteration of metabolites and lipids was investigated using gas chromatography-mass spectrometry and nano electrospray ionization-mass spectrometry in oTR-treated NSCLC cells and a xenograft mouse model. oTR reduced amino acid and pyrimidine synthesis in NSCLC cells and xenograft tumors. Moreover, oTR reduced glycolytic function and decreased mitochondrial respiration function by inhibiting glutamine and fatty acid oxidation. Increased levels of phosphatidylcholine, phosphatidylethanolamine, and phosphatidylserine species suggested that oTR might act as a fatty acid oxidation inhibitor. In addition, the increased level of phosphatidylserine species implied that phosphatidylserine-mediated apoptosis occurred in oTR-treated NSCLC cells and xenograft tumor. The antiproliferative and apoptotic effects of oTR were mediated by the reduced p-ERK and p-AKT levels and increased cleaved Caspase-3 levels, respectively. This is the first study to investigate the metabolic alterations and anticancer activity of oTR in in vitro and in vivo models of NSCLC. Our results provide basis for the development of oTR-based therapeutic agent for patients with NSCLC.