This journal is kind of obscure and I can't get this article from my university library, but would be interested in seeing it in its entirety. If someone could get it to me as a PDF, I'd appreciate it. Cancer chemopreventatives, carcinogenesis, and cell culture happen to be among my specialties. Based on the abstract, I'll make a few comments. Of late, the Chinese have made a great effort in the area of chemopreventatives probably due to their long cutural history of traditional or herbal medicine. Many studies like the one in question have been published over the past 10-15 years using cultured human tumor cells treated with this or that naturally occurring agent including curcumin, resveratrol, silibinin, bitter melon extract, etc. Many of them show cytotoxic effects on tumor cells similar to those seen in the apple study. So, right away, we must ask, why haven't we stopped cancer using these agents?
Unfortunately, most of these studies suffer from the same failing. The apple study showed a dose-dependent killing of cultured human tumor cells and assayed several apoptosis-related or cell cycle-related peptides or proteins. This seems convincing because these assays test for peptides that are of current interest in apoptosis studies, but here they only confirm that the cells are dying and point to the stage of cell cycle in which they are dying, nothing more. The problem is that cells in culture can be killed by almost anything and it will occur in a dose-related manner. Increasing doses of any salt like NaCl, KCl, MgCl2, CaCl2; any amino acid like glutamine, alanine, or glycine; any sugar like glucose, sucrose, or mannose; hormones like insulin, transferrin, or estrogen; even distilled water will kill cultured cells with increasing doses. This doesn't mean that they are specific for tumor cells, just that they will kill cells in culture and when the cells die, their expression of Bax, Bcl, Cdk, and cyclins will change in predictable ways. The control that is usually missing from these studies is: *normal human cell lines* like cultured primary skin cells (keratinocytes) or fibroblasts or normal kidney cells or normal pancreas or normal gut epithelial cells. If the agent of interest kills tumor cells but must be used at 100-10,000 times higher doses to kill normal cells, then you may have something, but 98% of these studies don't do this simple but essential control. A great deal of confusion results when this control is lacking. There are several widely used and potent chemotherapy agents that have been used for decades and are still actively used today. These agents were originally derived from plant sources and include colchicine and colcemid (from crocus), taxol (from yew), vinblastine and vincristine (from periwinkle) and podophyllotoxin for etoposide (from mayapple). So it is quite reasonable to expect that there will be other phytochemicals that are yet to be discovered which will be highly effective in preventing tumor development or in killing tumor cells. Studies like this one using apple oligosaccharide however, are not at all convincing no matter what we may wish for...but I haven't seen the full paper just the abstract. Rob Walter, PhD Research Scientist, Retired Stroger Hospital of Cook County Rush University Medical School. On Tue, Apr 16, 2013 at 7:53 PM, David Doud <[email protected]> wrote: > http://www.ncbi.nlm.nih.gov/pubmed/23511050 > > Chinese study - "Oligosaccharide from apple induces apoptosis and cell > cycle arrest in HT29 human colon cancer cells." > > If I read the abstract correctly, this was published last month - > > Dunno - it would be nice if someone knowledgable could review this - > > If it were the opposite association, I bet there would be banner > headlines... > > David Doud > Grower, Indiana > 1/4" green, wet - nice to have a real spring this year - > > * > * > > > _______________________________________________ > apple-crop mailing list > [email protected] > http://virtualorchard.net/mailman/listinfo/apple-crop > >
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