David and Robert,
Your discussion has been interesting. I am forwarding your information
to my daughter who is a student at Oregon Health and Science University. She
is getting her degree in Dietetics and Nutrition and is insatiable when it
comes to learning. Thanks for posting on apple-crop.
Phil Glaize
Virginia grower.. heading into bloom
From: apple-crop-boun...@virtualorchard.net
[mailto:apple-crop-boun...@virtualorchard.net] On Behalf Of David Doud
Sent: Wednesday, April 17, 2013 9:07 PM
To: Apple-crop discussion list
Subject: Re: [apple-crop] apple anti-cancer research
On Apr 17, 2013, at 2:04 PM, robjwal...@gmail.com wrote:
David:
Thanks for the PDF. As I had thought, the only cell type studied was HT29,
a human colon cancer cell line. No other tumor cell types or, more
importantly, normal cell types were studied here. Proper experimental
controls were not done, so the results cannot be generalized beyond the
obvious findings...the apple extract used can kill one type of tumor cell in
tissue culture, but so can a thousand other things.
Also, there did not appear to be any vehicle controls used. The preparation
of the apple extract is given in great detail, but the final product is
dried powder. This powder had to be dissolved and sterilized before adding
it to cultured cells, but the solvent used as the vehicle for this is not
stated as far as I can tell, and it is never tested by itself to see if the
vehicle alone has any toxic effects on the cells. Often DMSO is used as a
vehicle for difficult to solubilize compounds and even diluted DMSO can
injure or kill cells depending on the dose and time of exposure. There are
'control' groups mentioned here and there in the paper, but a control group
of cells that simply has nothing added to it (no apple extract, no FU, no
vehicle) is not the same as a vehicle control. Because the study was
performed in considerable detail, one would hope that vehicle controls were
performed, but this must be stated explicitly in the paper or else it cannot
be assumed.
Interestingly, the authors cite another paper (reference 11) where they
showed that oral administration of LMWAP effectively protected
ICR mice against CRC (LMWAP is a mixture of polysaccharides isolated from
apples; CRC is colorectal carcinoma).
http://www.ncbi.nlm.nih.gov/pubmed/22429028
Again, this paper is not in my library's PDF collection, but if they are
referring to the ICR mice that I am familiar with
(http://www.taconic.com/wmspage.cfm?parm1=758), it is impossible to
demonstrate this effect in that mouse. The ICR mouse is just a regular
white mouse with an intact immune system. This experiment cannot be done in
such a mouse because it requires a mouse with a defective immune system that
will permit human colon carcinoma cells to grow unimpeded.
And so it goes...
Robert Walter
On Apr 16, 2013, at 11:32 PM, robjwal...@gmail.com wrote:
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
