DH_27, a right-half derivative of renieramycin T, induce apoptosis through inhibition of mTOR signaling for lung cancer suppression.

Inhibition of mTOR signaling pathway gains a lot of interests as promising strategies for cancer treatment. Recently, we have reported the anticancer potential of the other renieramycin T (RT) right-half compounds. The subsequent modifications were conducted to identify a novel compound capable of exerting anticancer activity through the inhibition of survival proteins and anti-apoptotic proteins. The right-half of RT analog, DH_27 was synthesized, and its activity was explored in this study. The cytotoxicity effects were defined with MTT assay and colony formation assay. The induction of apoptosis was elucidated through Hoechst33342/propidium iodide (PI) staining and Annexin V-FITC/PI staining, coupled with flow cytometry. Mitochondrial membrane potential was assessed using JC-1 staining to investigate mitochondrial-mediated apoptosis. An examination of apoptotic-related proteins and mTOR signaling proteins were evaluated. Binding affinity of DH_27 and mTOR and the stability of DH_27-stabilized protein-protein interactions were investigated using molecular docking and molecular dynamics simulation. DH_27 exhibited cytotoxic effects on NSCLC cells with an IC50 below 10 µM and hindered their ability to form colonies. Treatment with DH_27 induced apoptosis, as evidenced by reduced levels of the anti-apoptotic protein Bcl‑2 and increased cleavage of PARP and caspase-9. JC-1 staining revealed mitochondrial depolarization in DH_27-treated cells, further supporting apoptosis via the intrinsic pathway. Notably, DH_27 significantly downregulated p-mTOR/mTOR expression through stable interactions at both the allosteric and catalytic sites, leading to the suppression of downstream signaling pathways, including Akt and p85S6K. This study identifies DH_27 as a potent anticancer agent that inhibits mTOR through allosteric and catalytic mechanisms, suppressing Akt and p85S6K signaling. This leads to reduced cell growth and apoptosis, supporting DH_27 as a promising candidate for targeted anticancer therapy.