We need a natural PI3K inhibitor, Becky

[al from Canada]

Good morning folks,

I've posted about this many times before and would like to find an active PI3K inhibitor. It seems this expression has everything to do with the up-regulation of HER2 and many, many other anti-apoptosis factors and cell proliferation responses. There is considerable research with two specific PI3K down regulators; LY294002 and wortmannin, the latter being extracted from some kind of fungus. Recently, another protein has been linked with PI3K up-regulation, (abstract below).

Does our resident micro-biologist, or anyone else for that matter, have any suggestions?

Regards,
Al

Survivin, a member of the inhibitor of apoptosis protein family, is widely expressed in a variety of human cancer tissues. Survivin inhibits activation of caspases, and its overexpression can lead to resistance to apoptotic stimuli. In this study, survivin protein expression was assessed by immunohistochemical staining of 195 invasive breast cancer specimens. Overall, 79.5% of the tumors were positive for survivin. The expression of epidermal growth factor receptor (EGFR) family, human epidermal growth factor receptor 2 (HER2) and EGFR, was also examined in 53 cases, and consequently, it was indicated that survivin positivity might be correlated with the coexpression of HER2 and EGFR. To clarify the regulatory mechanism of survivin expression in breast cancer cells, the effect of HER2 and/or EGFR expression on the survivin levels was examined. It was revealed that the survivin protein level was up-regulated by the coexpression of HER2 and EGFR, leading to the increased resistance against etoposide-induced apoptosis in breast cancer cells. Conversely, survivin levels and apoptosis resistance were decreased when cells were treated with HER2-specific inhibitor, Herceptin. Although Herceptin could down-regulate both phosphatidylinositol 3-kinase (PI3K)/AKT signal and mitogen-activated protein/extracellular signal-related kinase (ERK) kinase 1 (MEK1)/ERK signal in HER2-positive breast cancer cells, PI3K-specific inhibitor but not MEK1-specific inhibitor could decrease the survivin levels. The present study clarified the regulatory mechanism of HER2 in the expression of survivin protein in breast cancer cells.

[RobinP]

Hi Al,
Sounds like you're pTEN deficient?





Ann Oncol. 2004 Oct;15(10):1510-6. Related Articles, Links [img]/entrez/query/egifs/http:--highwire.stanford.edu-icons-externalservices-pubmed-free-annonc-free.gif[/img]
Reduced PTEN expression in breast cancer cells confers susceptibility to inhibitors of the PI3 kinase/Akt pathway.

DeGraffenried LA, Fulcher L, Friedrichs WE, Grunwald V, Ray RB, Hidalgo M.

University of Texas Health Science Center at San Antonio, San Antonio, TX, USA.

The PTEN protein is a lipid phosphatase with putative tumor suppressing abilities, including inhibition of the PI3K/Akt signaling pathway. Inactivating mutations or deletions of the PTEN gene, which result in hyper-activation of the PI3K/Akt signaling pathway, are increasingly being reported in human malignancies, including breast cancer, and have been related to features of poor prognosis and resistance to chemotherapy and hormone therapy. Prior studies in different tumor models have shown that, under conditions of PTEN deficiency, the PI3K/Akt signaling pathway becomes a fundamental proliferative and survival pathway, and that pharmacological inhibition of this pathway results in tumor growth inhibition. This study aimed to explore further this hypothesis in breast cancer cells. To this end, we have determined the growth response to inhibition of the PI3K/Akt signaling pathway in a series of breast cancer cell lines with different PTEN levels. The PTEN-negative cell line displayed greater sensitivity to the growth inhibitory effects of the PI3K inhibitor, LY294002 and rapamycin, an inhibitor of the PI3K/Akt downstream mediator mTOR, compared with the PTEN-positive cell lines. To determine whether or not these differences in response are specifically due to effects of PTEN, we developed a series of cell lines with reduced PTEN protein expression compared with the parental cell line. These reduced PTEN cells demonstrated an increased sensitivity to the anti-proliferative effects induced by LY294002 and rapamycin compared with the parental cells, which corresponded to alterations in cell cycle response. These findings indicate that inhibitors of mTOR, some of which are already in clinical development (CCI-779, an ester of rapamycin), have the potential to be effective in the treatment of breast cancer patients with PTEN-negative tumors and should be evaluated in this setting.

PMID: 15367412 [PubMed - indexed for MEDLINE

[jojo]

Whoa!... This just goes over my head -- and I have a college dregree (though not in science)! I am just amazed at the extensive research you keep coming up with. It is hard to catch up with you guys! I REALLY appreciate your teamwork. I love the feeling of being in a large & caring team, especially when it comes to life-threatening issues!

Keep up the good job! :-)

[Becky]

Robin was good to remind me about Pten activation (of which beta glucans found primarily in maitake mushrooms help activate if you have an inactive form). I know that you mentioned once that Linda does take these. The problem is what is enough for an effect versus too much that can interfer with other supplements. I take six 545mg capsules of dried maitake a day.


Now for P13K inhibitors. One that is common and available is selenium (in most multi's and supplements as sodium selenate). It is NOT the selenium that is the inhibitor. It is that excess selenium is converted in the body as methylselanol (a more water soluble version that can be eliminated by the urinary tract). This version is a known P13K inhibitor and this version is also highly TOXIC. I write this in bold for everyone reading this to see, understand and continue to read this post with thoughfulness. Selenium in high doses is toxic, toxic, toxic (since excess is converted to this toxic form). A little too much isn't going to do anything but what exactly is a little too much (hence, my initial advice is to take supplementation to what is consider 100% of the RDA and then focus on food sources initially).

Foods that are a good source of selenium include fish (especially shellfish), red meat, grains (especially wheat germ which is easy to sprinkle on your cereal), eggs, chicken, liver and garlic. Brewer's yeast is also high in selenium.

Al - I will continue to look for you as some "experimentals" out there are actually vitamins under an experimental number.

Stay tuned

Becky

[al from Canada]

Good thought Robin, the problem with many of these studies is that they don't address the other multitude of interactions that may cause PTEN inhibition or PI3K over-expression for that matter...and we know that cancer has many x-talk fail-safes. I mentioned PI3K because it keeps cropping-up over and over and over.....
Thanks for your info, Becky. Doesn't sound like selenium is the supplement of choice. We'll keep digging...

Here is a link to an excellent summary of PI3K actions and if you notice on the chart, IP6 is involved but it looks like it is downstreamstream, I'm not a biology person.
Misregulation of inositol signalling pathways has been implicated in a variety of diseases, including hypertension, diabetes and neuronal disorders, prompting the developmt of pharmacological agents that re-establish normal inositol signalling....inhibitors of PI3K are candidates for therapeutic agents for cancers and related metabolic diseases."


http://www.nyu.edu/classes/ytchang/r...d%20review.pdf

Regards,
Al

[Becky]

Okay - here's another good one and this one is very, very interesting. Vanadium - like selenium is toxic but food sources include cereals especially buckwheat and oats, green beans, olive and peanut oils, carrots, cabbage, corn, parsley, garlic and sunflower seeds.

The interesting thing is that researchers are also looking at it in treating diabetes because it controls insulin resistance and the insulin pathway as well (scientific name of vanadium is sodium vanadate). Now - if you have read my posts from way back, I used think that besides Her 2 and ER/PR receptors on breast cancer cells that there could be insulin receptors. I have given up on this theory because they would have found them by now AND that insulin is a HUGE molecule - just enormous. But... it does enter into the same P13K pathway and the same inhibitors are being looked at for diabetes. (I just found this interesting is all...).

I will keep up the look and at work (since it is a chemical company that I work for).

Becky

[RobinP]

Al, what you are looking for is both effective and simplistic at inducing apoptosis in breast cancer cells via of IGF-I inhibition which leads to PI3K inactivation, its called vit. D. I brought up the use of vit D a few weeks ago and it's use by Dr. DiGiovanna in new clinical trails: trails-http://www.bcrfcure.org/rese_meet_digiovanna.html.



Interactions of vitamin D analogues with downstream effectors of insulin-like growth factor 1 (IGF-I) signalling

LC Lowe, C Mørk Hansen & KW Colston

Oncology, Gastroenterology Endocrinology and Metabolism, St Georges Hospital Medical School, London, UK.

Raised levels of IGF-I have been associated with risk of developing several cancers including breast carcinoma. In addition to promoting mitogenesis in breast cancer cells, a number of observations suggest a role for inhibition of apoptosis by IGF-I receptor activation. Ligand binding to IGF-IR leads to activation of both the phosphoinositide-3'-kinase (PI3K) and the Ras/Raf/MAPKinase pathways. Deprivation of serum growth factors induces apoptosis in MCF-7 breast cancer cells and this effect can be abrogated by supplementation of serum free medium (SFM) with IGF-I via activation of the PI3K pathway. Co-treatment of MCF-7 cells with the vitamin D analogue EB1089 can attenuate the anti-apoptotic actions of IGF-I. To investigate the mechanism(s) by which EB1089 prevents IGF-I-mediated cell survival we compared interactions between this analogue and IGF-I in parental MCF-7 cells and a stable subclone (MCF-7/VDR) that is resistant to the growth inhibitory and apoptosis inducing effects of vitamin D. IGF-I promoted survival of parental and MCF-7/VDR cells in SFM such that >90% viability was obtained with cultures incubated with 4nM IGF-I for 4 days. Co-treatment with 100nM EB1089 attenuated the effects of IGF-I in parental but not MCF-7/VDR cells. Attenuation of IGF-I effects in parental cells was accompanied by a decrease in IGF-I-mediated PI3K activation (as assessed by levels of phosphorylated Akt). Using phosphospecific antibodies we obtained evidence that EB1089 treatment of parental cells promotes the pro-apoptotic p38 MAPK but not the ERK/MAPK pathway. In addition MCF-7/VDR basally contain a higher proportion of phosphorylated to total Akt, compared with parental MCF-7 cells. This may in part account for their resistance to vitamin D analogues. However, both cell lines are sensitive to the PI3K inhibitor wortmannin suggesting that even in the presence of a higher proportion of phosphorylated Akt, MCF-7/VDR cell death can be induced by blocking this cell survival pathway.

This research is funded by The Breast Cancer Research Trust and the World Cancer Research Fund.

I attended a lecture several months ago given by Dr. Feldman where he discussed initiating his Phase I clinical trial of superphysiologic doses of Vitamin D with usual therapeutic doses of Alleve in prostate cancer patients(see article below)---he felt it was quite likely to be efficacious in breast cancer as well and certainly warranted a clinical trial. I contacted a researcher at MDAnderson already doing research on cox2inhibitors and her2neu breast cancer (on a DOD grant) and pointed out the relative simplicity of doing a similar trial in breast cancer. Have not heard back so far...

That said, Warning:

the doses of vitamin used are 75 times greater than therapeutic doses and require hospitalization during those days they are given--one day per week, with 6 days “off” to recover from it. I havew also included a description of complications of hypercalcemia to discourage anyone thinking of it. Sunbathing is much safer, but the tanner one gets, the less vitamin D is absorbed.



• Stanford Report, September 14, 2005
Painkiller-vitamin D combo slows prostate cancer growth
Human clinical trial under way after study finds treatment to be effective in cultures of cancer cells
BY MITZI BAKER

The growth of prostate cancer cells can be halted by combining a form of vitamin D, available only by prescription, with low doses of an over-the-counter painkiller, researchers at the School of Medicine have found. The combination reduced prostate cancer cell growth in a laboratory dish by up to 70 percent, according to the findings, published in the Sept. 1 issue of the journal Cancer Research.

The study's senior author, David Feldman, MD, professor of medicine, has been studying vitamin D for 25 years. He had shown in previous studies that a form of the vitamin, known as calcitriol, limits the growth of prostate cancer cells. Calcitriol, the active form of vitamin D, is the metabolite that is created in the body after consumption of vitamin D-containing food or exposure to the sun.
Feldman wanted to see if he could boost calcitriol's effects and lower the dose by using it with another drug. He and his colleagues, including urology professor Donna Peehl, PhD, who specializes in developing models of prostate cancer in cultured cells, found that by using calcitriol with nonsteroidal anti-inflammatory drugs, or NSAIDs, they could suppress prostate cancer growth in vitro even more, and with smaller doses, than using either drug alone.
"There is great enhancement when the drugs are given together, using what we think is a safe dose in humans," said Feldman. "It's hard to make an exact comparison, as we are talking about cells in a dish and not a person." Still, based on the findings, he and his colleagues have already begun a clinical trial in men who have a post-treatment recurrence of prostate cancer. Both calcitriol and nonselective NSAIDs have been used in humans for years, and the safety and risks of these drugs are well known.
According to the Centers for Disease Control and Prevention, nearly 30,000 men die annually in the United States from prostate cancer. Among cancers, only lung cancer kills more men. Although prostate cancer is often a slow-growing, noninvasive type of cancer, in some cases a deadly migration of cancer cells invades other parts of the body.
The standard treatment for such cases is hormone therapy, but that treatment ultimately does not work for most patients. Slowing the growth of the prostate cancer cells could buy time for patients before beginning this last-ditch therapy.
Over the course of Feldman's years of vitamin D research, he and others had determined that the vitamin has several actions that make it useful in cancer therapy. While a great deal is now known about these effects, there is still much to be learned about how the vitamin stymies tumor growth.
To get an idea of what calcitriol does on a genetic level to halt tumor growth, the researchers used a cDNA microarray, a tool that provides an overview of the genetic changes that occur when prostate cancer cells react to calcitriol. The researchers discovered that two of the affected genes are critical in the production and breakdown of prostaglandins—hormones that cause a range of physiological effects, including inflammation. Inflammation, in turn, is also associated with cancer growth.
Like calcitriol, NSAIDs also block prostaglandin production. Thus, it seemed logical to test calcitriol in various combinations with NSAIDs to see if the double whammy could knock out prostate cancer better than either drug alone, explained study leader Jacqueline Moreno, PhD, a postdoctoral scholar in Feldman's lab.
When the researchers began the study, which was done on cells in culture, they were using selective NSAIDs, such as Vioxx and Celebrex. These drugs specifically target the prostaglandin pathway, reducing the gastrointestinal side effects of the nonselective NSAIDs. But after Vioxx was pulled from the market last year due to cardiovascular risks, the researchers switched to using two nonselective NSAIDs, ibuprofen and naproxen, so that the controversy over selective NSAIDs wouldn't cast a shadow over their work.
The group saw a 25 percent reduction in prostate cell growth using only calcitriol, and approximately the same reduction using only ibuprofen and naproxen. But when they combined calcitriol and an NSAID, they saw up to a 70 percent reduction. This result was obtained using from one-half to one-tenth the concentration required for either of the drugs used alone.
The group's findings are the basis of a new clinical trial Feldman has begun with oncologist Sandy Srinivas, MD, assistant professor of medicine. Men who have been treated for prostate cancer, but who are experiencing a recurrence, take naproxen twice a day combined with a high, once-weekly dose of calcitriol. Weekly administration of calcitriol avoids a pitfall of earlier studies that used daily dosing: too much calcium in the blood, a condition called hypercalcemia, which can lead to kidney stones.
Feldman's group uses calcitriol for both the cell culture studies and the clinical trial to ensure that enough of the active form of vitamin D is in the patients to be effective. Feldman emphasized that calcitriol is available by prescription only. "We don't want the patient to think that if they take over-the-counter vitamin D, it will work in the same way," he said.


Staff research scientist Aruna Krishnan, PhD, research associate Srilatha Swami, PhD, and urology postdoctoral scholar Larisa Nonn, PhD, also contributed to this work, which was funded by grants from the National Institutes of Health and the Department of Defense.

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
• Increased calcium levels may cause the following:
• Nausea
• Vomiting
• Alterations of mental status
• Abdominal or flank pain (The workup of patients with a new kidney stone occasionally reveals an elevated calcium level.)
• Constipation
• Lethargy
• Depression
• Weakness and vague muscle/joint aches
• Polyuria
• Headache
• Severe elevations in calcium levels may cause coma.
• Elderly patients are more likely to be symptomatic from moderate elevations of calcium levels.
• Hypercalcemia of malignancy may lack many of the features commonly associated with hypercalcemia caused by hyperparathyroidism.
• Hypercalcemia associated with renal calculi, joint complaints, and ulcer disease is more likely to be caused by hyperparathyroidism.

[Tom]

Dear Al and Becky,

I have had this piece of an article floating around my desktop for a few weeks and noticed your post regarding PI-3K inhibition. I had been researching articles on fibrotic lung disease and COPD, as a dear friend is going down the tubes fast with such a condition. I purchased her some IP-6 from the Vitamin Shoppe, and it is called Cell Forte. The "forte" name relates to a large study that uses retinoids to treat emphysema. I stumbled on this article, but do not have the source close at hand. When I have had a little sleep and can look for it again, I will post it as well. The part of the research that is germaine to your PI-3K quandry is below:




Mechanism of Cancer Suppression

The mechanism by which IP6 or myo-inositol exert chemopreventive and
anti-cancer effects is not completely understood. IP6 is rapidly
absorbed by cells (in vitro and in vivo) and metabolized to lower
phosphates and inositol (reviewed by Shamsuddin). It has been suggested
that lower inositol phosphates may mediate cancer inhibition, although
direct evidence for this is lacking. Both IP6 and its lower phosphates have
metal chelating activity and may interfere with tumor formation by suppressing
metal catalyzed oxidation of fats. Alternatively, IP6 may block the activity
of key enzyme(s) affecting cell proliferation. One enzyme candidate is PI-3
kinase which plays a central role in signal transduction and cell
transformation triggered by growth factor or tumor promoter. IP6 has been
reported to inhibit PI-3 kinase activity in vitro (Z. Dong, Univ. of
Minnesota, Austin). While this enzyme inhibition may explain the
chemopreventive effect of IP6, it is not known whether it mediates IP6's
effect on pre-existing tumors or
established cancer cells. Other, as yet, unknown mechanism may be
involved in the anti-cancer effect of IP6.

[Tom]

Just me again. In a brief moment of clarity, I found the original article, and the link is posted below, as well as the body of text:

http://www.thehormoneshop.com/ip6.htm#Beneficial Effects of IP6 and Inositol

What is IP6 (Inositol Hexaphosphate)?
Possesses Broad Range of Bioactivities
Most abundantly found in rice bran, above all other cereals.
Long used as safe natural antioxidant in various food products in Japan.
In Japan it is known to remove active oxygen in the body, suppressing lipid peroxide production and absorbs excess iron ions, having an effect on heart disease, liver dysfunction, dermatitis and other pathologic conditions caused thereby.
In Japan it is known further to prevent kidney stone formation and cholesterol deposition.
In Japan there have recently been, an increasing number of papers available concerning its immunity-enhancing and anticancer actions.



Beneficial Effects of IP6 and Inositol


The symposium started with a discussion of chemistry and usage of rice
components. S. Ogawa (Keio University) presented an impressive overview
of chemical structures and uses of myo-inositol and its related
compounds. T. Osawa (Nagoya University) discussed the protective role of rice
antioxidants in oxidative stress and Y. Watanabe (Ehime University, Matsuyama)
reviewed the synthesis of inositol triphosphate and phospholipids.


A large portion of the symposium was devoted to IP6 and its parent
molecule, inositol. It is difficult to summarize all the studies
presented at the conference. This article will touch upon major
findings of relevance to disease prevention and treatment.

Back to Index


Cancer


Let's consider the advances against cancer. A renowned epidemiologist
reviewed studies linking diet and life style to cancer (S.Sugano, Cancer
Institute, Tokyo). It's been known for sometime that consumption of whole
grains, vegetables and fruits is linked to reduced cancer risk. These foods
are rich in fiber which has been shown to protect against both colonic and
mammary cancer (reviewed by B.S. Reddy and L. A. Cohen, American Health
Foundation, New York). However, as it became apparent at the symposium, fiber
is not the sole anticarcinogen since other substances in fiber-containing
foods also exert protective influences on cancer. Thus, a multinational
epidemiologic study carried out in the mid 1980's had shown that foods rich in
phytate (IP6) but poor in fiber, such as cereals and grains, correlated better
with reduced risk of colon cancer than phytate-poor fiber foods such as fruits
and vegetables (Graf and Eaton, Cancer 1985; 56:717-718). IP6 is a strong
chelating agent and certain metals are known to promote cancer through
generationof reactive free radicals from oxidation of fats. IP6 also plays an
important role in regulating cell proliferation and differentiation.


In 1988, the first two studies were published, reporting inhibitory
effects of purified IP6 on tumor formation in experimental animals. One
study (Shamsuddin et al. Carcinogenesis 9:577-80) showed suppression of
cancer of the large bowel by IP6 and theother study (Jariwalla et al.
Nutr. Res. 8: 813-27) demonstrated reduction of the incidence and size
of soft-tissue tumors (fibrosarcomas) promoted by dietary factors.
Since then, a number of experimental studies have confirmed the
anti-cancer action of IP6 (reviewed by I. Vucenik and A.K.M. Shamsuddin, Univ.
of Maryland, Baltimore). The compound has been shown to inhibit various
rodent and human cancer cell lines in vitro and to protect against growth of
diverse cancers in vivo. Protective effects have been seen against cancers of
the breast, colon, pancreas, liver, skin and connective tissue. In vivo,IP6
not only prevents carcinogen-induced tumor development but it also interferes
with growth of pre-formed, transplanted tumors, suggesting that it may play a
role in both cancer prevention and treatment.


The step at which IP6 acts during tumor development varies depending
upon the type of cancer studied. In colon carcinogenesis, IP6 was shown to
suppress bowel cancer when given before, during and even several months after
carcinogen administration (Shamsuddin and colleagues, Univ. of Maryland).In
a multi-organ rat carcinogenesis model, IP6 administered (as phytic acid)
during the promotion stage suppressed hepatic tumors but had no influence on
development of esophagal, colonic, pancreatic, renal and thyroid tumor lesions
(M. Hirose, National Institute of Health Sciences, Tokyo). In a
two-stage model of carcinogenesis in mouse skin, IP6 inhibited tumor
formation when given during the initiation stage but not during tumor
promotion, indicating differential sensitivity of skin cancer (T. Ishikawa,
Univ. of Tokyo). Clinical studies in humans against different tumor types
would be useful. Awaiting such studies,
what can be said presently is that naturally-occurring salt forms of IP6
appear to be safe in animal studies even when used at higher than
physiologic dosages.


The role of myo-inositol as a chemopreventive agent was also discussed.
It is another phytochemical with low toxicity and ability to inhibit
carcinogenesis in various organs which include mammary gland, colon and
lung. In studies evaluating its chemopreventive activity in lung
carcinogenesis (L. W. Wattenberg, Univ. of Minneapolis, Minnesota), it
was reported that myo-inositol has unusual properties, manifesting a
capacity to prevent lung cancer when given during separate phases of the
carcinogenic process as well as throughout the entire course of the process.
When administered throughout the carcinogenic process, it's effects were found
to be additive. Another study reported on suppression of liver cancer by oral
administration of myo-inositol, thus adding to the diverse spectrum of tumors
affected by this naturally-derived plant constituent (H. Nishino, Kyoto Prefectual
University of Medicine). Myo-inositol has also been reported to enhance the
anti-cancer action of IP6 in other animal studies.

Back to Index


Mechanism of Cancer Suppression
The mechanism by which IP6 or myo-inositol exert chemopreventive and
anti-cancer effects is not completely understood. IP6 is rapidly
absorbed by cells (in vitro and in vivo) and metabolized to lower
phosphates and inositol (reviewed by Shamsuddin). It has been suggested
that lower inositol phosphates may mediate cancer inhibition, although
direct evidence for this is lacking. Both IP6 and its lower phosphates have
metal chelating activity and may interfere with tumor formation by suppressing
metal catalyzed oxidation of fats. Alternatively, IP6 may block the activity
of key enzyme(s) affecting cell proliferation. One enzyme candidate is PI-3
kinase which plays a central role in signal transduction and cell
transformation triggered by growth factor or tumor promoter. IP6 has been
reported to inhibit PI-3 kinase activity in vitro (Z. Dong, Univ. of
Minnesota, Austin). While this enzyme inhibition may explain the
chemopreventive effect of IP6, it is not known whether it mediates IP6's
effect on pre-existing tumors or
established cancer cells. Other, as yet, unknown mechanism may be
involved in the anti-cancer effect of IP6.

[al from Canada]

Sensitization of breast cancer cells to radiation by trastuzumab

Ke Liang1, Yang Lu1, Weidong Jin1, K. Kian Ang2, Luka Milas3 and Zhen Fan1



1 Departments of Experimental Therapeutics, 2 Radiation Oncology, and 3 Experimental Radiation Oncology, The University of Texas M. D. Anderson Cancer Center, Houston, TX

Requests for Reprints:Zhen Fan, Unit 36, The University of Texas M. D. Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX 77030. Phone: (713) 745-3560; Fax: (713) 745-3562. E-mail: zfan@mdanderson.org

HER2, a member of the human epidermal growth factor (EGF) receptor family, not only plays important roles in the progression of breast cancer tumorigenesis and metastasis, but may protect cancer cells from conventional cytotoxic therapies as well. In the current study, we evaluated the effect of targeting HER2 on radiosensitization of human breast cancer cells. Using six breast cancer cell lines with various levels of HER2 (BT474, SKBR3, MDA453, MCF7, ZR75B, and MDA468), we found that trastuzumab (Herceptin), a humanized monoclonal antibody that may inhibit breast cancer cell proliferation but does not induce apoptosis when used alone, enhanced radiation-induced apoptosis of the cells in a HER2 level-dependent manner. We furthered this study in MCF7 cells transfected for high levels of HER2 (MCF7HER2). Compared with parental or control vector-transfected MCF7 cells, MCF7HER2 cells showed increased phosphorylation of at least two important HER2 downstream molecules, protein kinase B/Akt and mitogen-activated protein kinase (MAPK), and increased resistance to radiotherapy, as shown by reduced induction of apoptosis and increased cell clonogenic survival after radiation. Exposure of the cells to trastuzumab down-regulated the levels of HER2 and reduced phosphorylation levels of Akt and MAPK in MCF7HER2 cells, and sensitized these cells to radiotherapy. When specific inhibitors of the phosphatidylinositol 3-kinase (PI3-K) and MAPK kinase (MEK) pathways were used, we found that exposure of MCF7HER2 cells to the PI3-K inhibitor LY294002 inhibited Akt phosphorylation and radiosensitized the cells, whereas the radiosensitization effect by the MEK inhibitor PD98059 was relatively weaker, albeit the phosphorylation of MAPK was reduced by PD98059 treatment. Our results indicate that the PI3-K pathway might be the major pathway for trastuzumab-mediated radiosensitization of breast cancer cells

[RobinP]

Just one more thing to help lower PI3K that is simple to do. EXCERCISE and lower lipids and carbohydrates in order to decrease blood sugar and insulin levels. High insulin is associated with high IGF. If we can lower IGF, we may be able to lower PI3k pathways.

Mol Cancer Ther. 2006;5:187-196
© 2006 American Association for Cancer Research
Identification of magnetic resonance detectable metabolic changes associated with inhibition of phosphoinositide 3-kinase signaling in human breast cancer cells

Mounia Beloueche-Babari1, L. Elizabeth Jackson1, Nada M.S. Al-Saffar1, Suzanne A. Eccles2, Florence I. Raynaud2, Paul Workman2, Martin O. Leach1 and Sabrina M. Ronen1
1 Cancer Research UK Clinical Magnetic Resonance Research Group, The Institute of Cancer Research and The Royal Marsden NHS Foundation Trust; 2 Cancer Research UK Centre for Cancer Therapeutics, The Institute of Cancer Research, Sutton, Surrey, United Kingdom

Requests for reprints: Mounia Beloueche-Babari, Cancer Research UK Clinical Magnetic Resonance Research Group, Institute of Cancer Research and Royal Marsden NHS Foundation Trust, Downs Road, Sutton, Surrey SM2 5PT, United Kingdom. Phone: 44-208-661-3728; Fax: 44-208-661-0846. E-mail: Mounia.Beloueche-Babari@icr.ac.uk


Phosphoinositide 3-kinase (PI3K) is an attractive target for novel mechanism-based anticancer treatment. We used magnetic resonance (MR) spectroscopy (MRS) to detect biomarkers of PI3K signaling inhibition in human breast cancer cells. MDA-MB-231, MCF-7, and Hs578T cells were treated with the prototype PI3K inhibitor LY294002, and the 31P MR spectra of cell extracts were monitored. In every case, LY294002 treatment was associated with a significant decrease in phosphocholine levels by up to 2-fold (P < 0.05). In addition, a significant increase in glycerophosphocholine levels by up to 5-fold was also observed (P 0.05), whereas the content of glycerophosphoethanolamine, when detectable, did not change significantly. Nucleotide triphosphate levels did not change significantly in MCF-7 and MDA-MB-231 cells but decreased by 1.3-fold in Hs578T cells (P = 0.01). The changes in phosphocholine and glycerophosphocholine levels seen in cell extracts were also detectable in the 31P MR spectra of intact MDA-MB-231 cells following exposure to LY294002. When treated with another PI3K inhibitor, wortmannin, MDA-MB-231 cells also showed a significant decrease in phosphocholine content by 1.25-fold relative to the control (P < 0.05), whereas the levels of the remaining metabolites did not change significantly. Our results indicate that PI3K inhibition in human breast cancer cells by LY294002 and wortmannin is associated with a decrease in phosphocholine levels. [Mol Cancer Ther 2006;5(1):187–96]

cox inhibitors may not all be natural, but they are simple, available and with few side effects:

PubMed Citation
Articles by Hughes-Fulford, M.
Articles by Sayyah, S.
[Cancer Research 66, 1427-1433, February 1, 2006]
© 2006 American Association for Cancer Research
Cell, Tumor, and Stem Cell Biology

Arachidonic Acid Activates Phosphatidylinositol 3-Kinase Signaling and Induces Gene Expression in Prostate Cancer

Millie Hughes-Fulford1,2,3, Chai-Fei Li2, Jim Boonyaratanakornkit1,3 and Sina Sayyah2
1 Department of Veterans Affairs Medical Center; 2 Northern California Institute for Research and Education; and 3 University of California, San Francisco, California

Requests for reprints: Millie Hughes-Fulford, Laboratory of Cell Growth (151F), Veterans Affairs Medical Center, 4150 Clement Street, San Francisco, CA 94121. Phone: 415-750-6940; Fax: 415-750-6667; E-mail: milliehf@aol.com.

Essential fatty acids are not only energy-rich molecules; they are also an important component of the membrane bilayer and recently have been implicated in induction of fatty acid synthase and other genes. Using gene chip analysis, we have found that arachidonic acid, an -6 fatty acid, induced 11 genes that are regulated by nuclear factor-B (NF-B). We verified gene induction by -6 fatty acid, including COX-2, IB, NF-B, GM-CSF, IL-1ß, CXCL-1, TNF-, IL-6, LTA, IL-8, PPAR, and ICAM-1, using quantitative reverse transcription-PCR. Prostaglandin E2 (PGE2) synthesis was increased within 5 minutes of addition of arachidonic acid. Analysis of upstream signal transduction showed that within 5 minutes of fatty acid addition, phosphatidylinositol 3-kinase (PI3K) was significantly activated followed by activation of Akt at 30 minutes. Extracellular signal-regulated kinase 1 and 2, p38 and stress-activated protein kinase/c-Jun-NH2-kinase were not phosphorylated after -6 fatty acid addition. Thirty minutes after fatty acid addition, we found a significant 3-fold increase in translocation of NF-B transcription factor to the nucleus. Addition of a nonsteroidal anti-inflammatory drug (NSAID) caused a decrease in COX-2 protein synthesis, PGE2 synthesis, as well as inhibition of PI3K activation. We have previously shown that NSAIDs cause an inhibition of arachidonic acid–induced proliferation; here, we have shown that arachidonic acid–induced proliferation is also blocked (P < 0.001) by PI3K inhibitor LY294002. LY294002 also significantly inhibited the arachidonic acid–induced gene expression of COX-2, IL-1ß, GM-CSF, and ICAM1. Taken together, the data suggest that arachidonic acid via conversion to PGE2 plays an important role in stimulation of growth-related genes and proliferation via PI3K signaling and NF-B translocation to the nucleus. (Cancer Res 2006; 66(3): 1427-33)

Al and Becky, this one might interest you.

Hot of the press Feb '06 found on my wanders.

The outlines in the fog get a little clearer.

Arachidonic Acid is part of the eicosanoid pathway, a derivate of omega six. It is more complex as usual and the three and six pathways interlink, and PGE 2 production is dependent on the ratio of three / six intake, but from what I have read and recall significant imbalance exacerbates PGE 2 production.

A potential implication is that balancing the thress and sixes will impact on cancer growth. This would tie in with the findings in general studies suggesting lower risk / progression.

As usual please check this out for your self as the posts are very much off the cuff.


RB




http://cancerres.aacrjournals.org/cg...ract/66/3/1427

ABSTRACT


Arachidonic Acid Activates Phosphatidylinositol 3-Kinase Signaling and Induces Gene Expression in Prostate Cancer
Millie Hughes-Fulford1,2,3, Chai-Fei Li2, Jim Boonyaratanakornkit1,3 and Sina Sayyah2

1 Department of Veterans Affairs Medical Center; 2 Northern California Institute for Research and Education; and 3 University of California, San Francisco, California

Requests for reprints: Millie Hughes-Fulford, Laboratory of Cell Growth (151F), Veterans Affairs Medical Center, 4150 Clement Street, San Francisco, CA 94121. Phone: 415-750-6940; Fax: 415-750-6667; E-mail: milliehf@aol.com.

Essential fatty acids are not only energy-rich molecules; they are also an important component of the membrane bilayer and recently have been implicated in induction of fatty acid synthase and other genes. Using gene chip analysis, we have found that arachidonic acid, an {omega}-6 fatty acid, induced 11 genes that are regulated by nuclear factor-{kappa}B (NF-{kappa}B). We verified gene induction by {omega}-6 fatty acid, including COX-2, I{kappa}B{alpha}, NF-{kappa}B, GM-CSF, IL-1ß, CXCL-1, TNF-{alpha}, IL-6, LTA, IL-8, PPAR{gamma}, and ICAM-1, using quantitative reverse transcription-PCR. Prostaglandin E2 (PGE2) synthesis was increased within 5 minutes of addition of arachidonic acid. Analysis of upstream signal transduction showed that within 5 minutes of fatty acid addition, phosphatidylinositol 3-kinase (PI3K) was significantly activated followed by activation of Akt at 30 minutes. Extracellular signal-regulated kinase 1 and 2, p38 and stress-activated protein kinase/c-Jun-NH2-kinase were not phosphorylated after {omega}-6 fatty acid addition. Thirty minutes after fatty acid addition, we found a significant 3-fold increase in translocation of NF-{kappa}B transcription factor to the nucleus. Addition of a nonsteroidal anti-inflammatory drug (NSAID) caused a decrease in COX-2 protein synthesis, PGE2 synthesis, as well as inhibition of PI3K activation. We have previously shown that NSAIDs cause an inhibition of arachidonic acid–induced proliferation; here, we have shown that arachidonic acid–induced proliferation is also blocked (P < 0.001) by PI3K inhibitor LY294002. LY294002 also significantly inhibited the arachidonic acid–induced gene expression of COX-2, IL-1ß, GM-CSF, and ICAM1. Taken together, the data suggest that arachidonic acid via conversion to PGE2 plays an important role in stimulation of growth-related genes and proliferation via PI3K signaling and NF-{kappa}B translocation to the nucleus. (Cancer Res 2006; 66(3): 1427-33)

Isn't chamomille a natural p13k inhibitor? I have a vague memory of having this discussion with Al, but now I'm doubting myself. Has anyone else seen this? I can try to dig out the reference...

Jeff

Int J Oncol. 2006 Apr;28(4):985-93. Links

Leptin receptor expression and cell signaling in breast cancer.

Frankenberry KA, Skinner H, Somasundar P, McFadden DW, Vona-Davis LC.

Department of Surgery, West Virginia University, Morgantown, WV 26506, USA.

Obesity is considered a risk factor for many cancers, including breast cancer. Our laboratory has previously shown that leptin is mitogenic in many cancer cell lines, including breast. Information regarding the effects of high leptin levels on leptin receptor expression and signaling is lacking. The purpose of this study was to characterize leptin receptor expression in response to leptin in breast cancer cells. In addition, SOCS-3 expression (a leptin inducible inhibitor of leptin signaling), plus MAPK and PI3K signaling, were examined to determine their role in leptin-induced cell proliferation. Breast cancer cell lines, ZR75-1 and HTB-26, were treated with 0, 4, 40 or 80 ng/ml of leptin. Multiplex RT-PCR was performed to determine relative mRNA expression levels of the human short (huOB-Ra) or long (huOB-Rb) leptin receptor isoforms, or SOCS-3. MAPK and PI3K signaling was analyzed by phosphorylation of ERK and Akt, respectively, via Western blotting. Cell proliferation and inhibitor studies were analyzed by MTT assay. HTB-26 and ZR75-1 both expressed huOB-Ra, huOB-Rb and SOCS-3 mRNA; however, mRNA expression levels generally remained unchanged over time with leptin treatment. MAPK and PI3K pathways were activated in the presence of leptin over time. MAPK and PI3K inhibitors significantly blocked leptin-induced proliferation. Higher levels of circulating leptin contribute to breast cancer proliferation by activation of the MAPK and PI3K signaling pathways involved in cell growth and survival. The mitogenic effects of leptin are not a consequence of altered leptin receptor or SOCS-3 mRNA expression.

PMID: 16525650 [PubMed - in process]