Title:Synergistic Effects of Ethanol Extract of Allium sativum (Garlic) with DAPT and ATRA on Notch Signaling Targeted Molecular Action on Lung Cancer Cell line (A549)
Volume: 21
Issue: 13
Author(s): Ragavi Ravichandran, D. David Wilson, S. Viswanathan, Siddikuzzaman, Lucia Bonati, Selvamani Rajendran and V. Berlin Grace*
Affiliation:
- Department of Biotechnology, Karunya Institute of Technology and Sciences, Coimbatore, India
Keywords:
Combination treatment, notch signaling, A549 cells, p53, RT-PCR, GC-MS analysis.
Abstract:
Background: The activated oncogenic Notch signalling is an emerging target to treat cancer
progression and recurrence. Synthetic inhibitors of Notch receptors are in pre-clinical studies. However,
the overexpression of Notch signalling molecules at the gene level needs to be regulated to control cancer
progression.
Objective: We propose that this can be achieved by gene-regulatory drugs in combination with natural
phytochemical compounds.
Methods: The ethanol extract of Allium sativum alone and in combination with DAPT and ATRA were
evaluated for cytotoxicity on A549 cells by MTT and Trypan blue assays. Their effects on Notch 1, Hes 1
and p53 gene expressions were studied by RT-PCR and qPCR. Their inhibition on metastatic invasion of
A549 cells was analyzed by in vitro wound scratch assay. The phytochemicals of the extract were
identified by GC-MS analysis.
Results: Many organosulfur compounds having anti-cancer potency were identified in GC-MS. The
combination treatment with 50μg (IC50) of garlic extract exhibited a highly significant (P≤0.01)
synergistic inhibitory effect on A549 cell growth and migration. It has also significantly reduced the
expression of Notch 1 and Hes 1 oncogenes and enhanced p53 gene expression, compared with the
individual treatments. This indicates the synergistic action of the extract on the downregulation of Notch
signalling at the mRNA level.
Conclusion: Our study results imply that the combination therapies have potent molecular treatment
action via down-regulating Notch signaling target genes and upregulating p53 gene expression as an
underlying mechanism of inhibitory action on A549 lung cancer cells.