Substituents introduction of methyl and methoxy functional groups on resveratrol stabilizes mTOR binding for
Zin Zin Ei1,2, Satapat Racha1,2,3, Preedakorn Chunhacha2,4
1Department of Pharmacology and Physiology, Faculty of Pharmaceutical Sciences, Chulalongkorn university, Bangkok, 10330, Thailand.
Abstract:
The regulation of the mammalian target of rapamycin (mTOR) protein by cancer cells can lead to uncontrol of cancer cell growth and cancer therapy resistance. The drug discovery of the anticancer agent 5-(3-hydroxy-4-methoxyphenethyl)-2-methoxy-3-methylphenol (SM-3), a derivative of resveratrol by substituting a methyl group at the hydroxy group of ring A and adding a methoxy group at the para position of ring B, shows promising potential for targeting autophagy to induce cell death and suppress cancer stem cells (CSCs) through the inhibition of the mTOR protein. In human lung cancer cells, SM-3 showed greater efficacy, with lower IC50 values of 72.74 ± 0.13, 67.66 ± 0.10, and 43.24 ± 0.11 µM in A549, H292, and H460 cells, respectively, compared to the parent compound, Resveratrol (Res). Moreover, the selectivity index (SI) values for BEAS2B cells compared to tumor cells treated with SM-3 were 10.99, 11.81, and 18.49 for A549, H292, and H460 cell lines, respectively. Therefore, SM-3 treatment led to reduced proliferation rates and colony formation in lung cancer cells. In our study, spheroids treated with SM-3 showed a higher proportion of dead spheroids compared to those treated with Res. Additionally, SM-3 treatment resulted in decreased expression of stem cell markers (CD133, CD44, and ALDH1A1) and transcription factors (OCT4, NANOG, and SOX2) in spheroids and organoids from human lung cancer cells by inhibiting the mTOR/pAkt pathway. SM-3 was also found to induce autophagic cell death, as indicated by Monodansylcadaverine staining, acidic vesicle formation, and the conversion of LC3BI to LC3BII. Using MM/GBSA calculations, SM-3 exhibited a stronger binding affinity (-25.09 kcal/mol) compared to Res (-18.85 kcal/mol). SM-3 also displayed greater stability during the entire simulation, maintaining lower RMSD values of 2-3 Å even after 80 ns. In summary, the introduction of methyl and methoxy functional groups on Res to create SM-3 effectively suppressed cancer spheroids and organoids formation in lung cancer cells by targeting the upstream mTOR/pAkt pathway.
Insights
The novel compound SM-3, a resveratrol derivative, effectively suppresses lung cancer growth and stemness by inhibiting the mTOR pathway. SM-3 demonstrates superior efficacy and selectivity over resveratrol, inducing cancer cell death and reducing tumor formation.
Area of Science:
- Oncology
- Medicinal Chemistry
- Molecular Biology
Background:
- Dysregulation of the mammalian target of rapamycin (mTOR) pathway is implicated in cancer cell proliferation and therapeutic resistance.
- Cancer stem cells (CSCs) contribute to tumor recurrence and treatment failure.
- Resveratrol derivatives are explored for their anticancer potential.
Purpose of the Study:
- To investigate the anticancer efficacy of a novel resveratrol derivative, SM-3, against human lung cancer cells.
- To elucidate the mechanism of action of SM-3, focusing on mTOR inhibition, autophagy induction, and CSC suppression.
- To compare the efficacy and selectivity of SM-3 with its parent compound, Resveratrol (Res).
Main Methods:
- Synthesis and characterization of SM-3, a modified resveratrol compound.
- In vitro evaluation of SM-3's cytotoxicity and selectivity in various human lung cancer cell lines (A549, H292, H460) and a normal cell line (BEAS2B).
- Assessment of SM-3's effects on cancer cell proliferation, colony formation, spheroid/organoid growth, and stem cell marker expression.
- Analysis of autophagy induction using Monodansylcadaverine staining and LC3B conversion.
- Molecular docking (MM/GBSA) and molecular dynamics simulations to evaluate binding affinity and stability of SM-3 to mTOR.
- Western blotting to assess the impact of SM-3 on the mTOR/pAkt pathway and stemness-related proteins.
Main Results:
- SM-3 exhibited significantly lower IC50 values and higher selectivity index (SI) compared to Resveratrol in lung cancer cells.
- SM-3 effectively inhibited lung cancer cell proliferation, colony formation, and suppressed the formation of spheroids and organoids.
- SM-3 treatment led to a decrease in the expression of key stem cell markers (CD133, CD44, ALDH1A1) and transcription factors (OCT4, NANOG, SOX2).
- SM-3 induced autophagic cell death and demonstrated a stronger binding affinity and greater stability to the mTOR protein compared to Resveratrol.
- SM-3's anticancer effects were mediated through the inhibition of the mTOR/pAkt pathway.
Conclusions:
- SM-3 is a potent anticancer agent with enhanced efficacy and selectivity against lung cancer compared to Resveratrol.
- SM-3 suppresses lung cancer progression by inhibiting the mTOR/pAkt pathway, inducing autophagy, and eliminating cancer stem cells.
- SM-3 holds significant promise as a therapeutic candidate for lung cancer treatment, particularly for targeting therapy-resistant and stem-like cancer cells.
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