The study – published in Carcinogenesis – shows that grape seed extract (GSE) kills head and neck squamous cell carcinoma cells (HNSCC), while leaving healthy cells unharmed, in both in vitro and in vivo models.
Led by Dr Rajesh Agarwal of the University of Colorado Cancer Center, the researchers reported that the grape seed extract reduced growth of certain cancers by up to 67% and resulted in growth reduction, DNA damage, and cell death (apoptosis) of cancer cell lines.
“These findings show that GSE targets both DNA damage and repair, and provide mechanistic insights for its efficacy selectively against head and neck squamous cell carcinoma both in cell culture and mouse,” said the research team.
Agarwal commented that the findings demonstrated "a rather dramatic effect" noting that the beneficial results seems to stem from the ability of healthy cells to withstand cellular stresses to a greater extent than a cancer cell can.
He explained that the grape seed extract creates conditions that are unfavourable to growth of cells. Specifically, the extract both damages cancer cells' DNA (through increased reactive oxygen species) and stops the pathways that allow repair, he said.
When this stress occurred, cancer cells were killed whilst the team "saw absolutely no toxicity to the mice, themselves."
"I think the whole point is that cancer cells have a lot of defective pathways and they are very vulnerable if you target those pathways. The same is not true of healthy cells," said Agarwal.
The researchers explained that whilst previous research has suggested the ability of GSE to block the growth of certain cancers, the detailed effects (both in vitro and in vivo) and molecular mechanisms behind such results are currently “largely unknown.”
“Our results in the present study showed that dietary supplement GSE triggers DNA damage through an accumulation of intra-cellular ROS and decrease in DNA repair enzymes, leading to cell cycle arrest and apoptotic cell death in human HNSCC cells in culture,” said the research team.
They revealed that similar results were also observed in the mouse model.
Agarwal and his team argued that given the limited therapeutic options available against head and neck cancers; their results support a call for additional studies investigating the effects of dietary grape seed extract supplementation against the cancers.
Published online ahead of print, doi: 10.1093/carcin/bgs019
“Generation of reactive oxygen species by grape seed extract causes irreparable DNA damage leading to G2/M arrest and apoptosis selectively in head and neck squamous cell carcinoma cells”
Authors: S. Shrotriya, G. Deepa, M. Gu, M. Kaur, A.K. Jain, et al