Delta Tocotrienal Inhibit mTOR Pathway by Modulating Glutamine Uptake and Transporters in Non‐Small Cell Lung Cancer

Lung cancer, with the majority of cases being non‐small cell lung cancer (NSCLC), is one of the leading causes of death among cancers. NSCLC has exhibited high rate of glutamine dependency during its growth and development. It has also been shown that glutamine uptake plays a mandatory role in the uptake of essential amino acid and in activation of mTOR kinase. SLC1A5 and SLC7A5, glutamine transporters, exhibit an important role in the development of NSCLC by transporting glutamine and essential amino acid into the proliferating tumors. Therefore, SLC1A5 and SLC7A5 are key drug targets with potential pharmacological importance. The aim of this study was to probe dysregulated glutamine and essential amino acids (EAA) metabolism in NSCLC, while investigating the effect of T3 on glutamine transporter and mTOR pathways. H1299 and A549 cells were cultured with/without T3 (30μM) followed by extraction of the intra‐cellular metabolites. The endometabolome of the cells was determined by 1 H‐NMR spectroscopy. Changes in specific metabolite concentrations upon intervention with δT were quantified with the Chenomx‐NMR Suite . MTS assay and FITC Annexin V stained flow cytometry analysis were performed to determine the anti‐proliferative effects and induction of apoptosis by T3. The expression of glutamine transporters and mTOR pathway proteins were assessed using western blot analysis. The data shows that T3 significantly inhibited glutamine uptake in H1299 cells. The inhibition of glutamine uptake into proliferating cells resulted in dose dependent inhibition of cell proliferation and induction of apoptosis in both cell lines. Further validation using western blot data exhibits inhibition of SLC7A5 glutamine transporter and mTOR pathway proteins (P‐mTOR, mTOR, P‐AKT, AKT, S6K, c‐MYC. MMP‐9, and Bcl‐XL) by T3 in a dose dependent manner. Our findings suggest that the anticancer effects of T3 may occur via downregulation of mTOR1 pathway induced by inhibition of glutamine transporters.