Target identification of grape seed extract in colorectal cancer using drug affinity responsive target stability (DARTS) technique: role of endoplasmic reticulum stress response proteins.
Various natural agents, including grape seed extract (GSE), have shown considerable chemopreventive and anti-cancer efficacy against different cancers in pre-clinical studies; however, their specific protein targets are largely unknown and thus, their clinical usefulness is marred by limited scientific evidences about their direct cellular targets. Accordingly, herein, employing, for the first time, the recently developed drug affinity responsive target stability (DARTS) technique, we aimed to profile the potential protein targets of GSE in human colorectal cancer (CRC) cells. Unlike other methods, which can cause chemical alteration of the drug components to allow for detection, this approach relies on the fact that a drug bound protein may become less susceptible to proteolysis and hence the enriched proteins can be detected by Mass Spectroscopy methods. Our results, utilizing the DARTS technique followed by examination of the spectral output by LC/MS and the MASCOT data, revealed that GSE targets endoplasmic reticulum (ER) stress response proteins resulting in overall down regulation of proteins involved in translation and that GSE also causes oxidative protein modifications, specifically on methionine amino acids residues on its protein targets. Corroborating these findings, mechanistic studies revealed that GSE indeed caused ER stress and strongly inhibited PI3k-Akt-mTOR pathway for its biological effects in CRC cells. Furthermore, bioenergetics studies indicated that GSE also interferes with glycolysis and mitochondrial metabolism in CRC cells. Together, the present study identifying GSE molecular targets in CRC cells, combined with its efficacy in vast pre-clinical CRC models, further supports its usefulness for CRC prevention and treatment.
Molly M
MM
Derry
Ranganatha R
RR
Somasagara
Komal
K
Raina
Sushil
S
Kumar
Joe
J
Gomez
Manisha
M
Patel
Rajesh
R
Agarwal
Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, 12850 E. Montview Blvd, C238, Room V20-2118, Aurora, CO 80045, USA. Chapla.Agarwal@UCDenver.edu.
Chapla
C
Agarwal
D000972:Antineoplastic Agents, Phytogenic / Q000378:metabolism* / Q000627:therapeutic use; D045744:Cell Line, Tumor; D015179:Colorectal Neoplasms / Q000378:metabolism* / Q000517:prevention & control; D019587:Dietary Supplements; D015536:Down-Regulation; D059865:Endoplasmic Reticulum Stress; D004734:Energy Metabolism; D056604:Grape Seed Extract / Q000378:metabolism* / Q000627:therapeutic use; D006801:Humans; D007700:Kinetics; D008715:Methionine / Q000737:chemistry; D008954:Models, Biological; D009363:Neoplasm Proteins / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000378:metabolism; D010084:Oxidation-Reduction; D010449:Peptide Mapping; D058539:Phosphatidylinositol 3-Kinase / Q000737:chemistry / Q000378:metabolism; D000081082:Phosphoinositide-3 Kinase Inhibitors; D011499:Protein Processing, Post-Translational; D055550:Protein Stability; D040901:Proteomics / Q000379:methods; D015398:Signal Transduction
D000972:Antineoplastic Agents, Phytogenic; D056604:Grape Seed Extract; D009363:Neoplasm Proteins; D000081082:Phosphoinositide-3 Kinase Inhibitors; D008715:Methionine; D058539:Phosphatidylinositol 3-Kinase