**BIOTECH AND PHARMA NEWS**

[Preciouslife1]

I am starting this thread to seperate the general biotech and pharma news from the PPHM thread where so much news will be flowing and give this thread its own forum.....

A WALL STREET JOURNAL ONLINE NEWS ROUNDUP
September 21, 2006 3:11 a.m.

ZURICH -- German pharmaceutical and chemical company Merck KGaA Thursday said it is buying the majority of Serono SA from the controlling Bertarelli family in a deal that values the Swiss pharmaceuticals firm at 16.6 billion Swiss francs ($13.3 billion).

Merck KGaA said it is buying a 64.5% stake in Serono for 1,100 francs a share that will give it 75.5% of the voting rights. The offer values Serono at 16.6 billion francs, with share options included in the calculation, a Merck spokeswoman told Dow Jones Newswires.

…The company also said that, as required by Swiss law, it will offer to buy out remaining Serono shareholders, likewise at 1,100 francs per share. The offer price represents a 20% premium to the share price as of Sept. 20. Serono shares closed at 915 francs in Zurich Wednesday.

Serono had put itself up for sale in 2005 but said in April it was reversing strategy and will focus on acquisitions. The company's controlling shareholder, the Bertarelli family, said at the time it had ended all talks regarding a sale of the company. Offers didn't adequately reflect Serono's prospects, it said.

Merck KGaA, which isn't related to U.S. company Merck & Co., tried earlier this year to buy Schering AG for ?77 a share, but was trumped by a subsidiary of rival Bayer AG, which offered ?86 a share.

[Preciouslife1]

Study Details Structural Changes Of A Key Catalytic Enzyme

Scientists at the Scripps Research Institute have detailed a new hypothesis of how a key catalytic enzyme, dihydrofolate reductase -- which is the target of several anticancer and antibiotic therapies-cycles through structural changes as it plays a critical role in promoting cell growth and proliferation.

Enzymes are complex proteins capable of catalyzing specific biochemical reactions in cells. While it has long been recognized that dynamic fluctuations in protein conformation or structure play a central role in enzyme catalysis, the new findings indicate that the "dynamic energy landscape" of the enzyme funnels it along a preferred pathway that actually minimizes the number and dimension of the energetic barriers to these catalytic changes.
"There is a growing awareness that the inherent motions of proteins are essential to their functions," said Peter Wright, who is chair of the Scripps Research Department of Molecular Biology and a member of the Skaggs Institute for Chemical biology at Scripps Research. "The importance of this study is that it reveals how dynamic structural fluctuations channel an enzyme through its reaction cycle-the thermal motions of the protein are harnessed to perform its biological function, in this case, catalysis. Knowledge of the excited-state conformations of proteins may offer new opportunities for drug design."
The researchers used nuclear magnetic resonance (NMR) to detect and characterize higher energy structural sub-states (excited states) of E. coli dihydrofolate reductase, which has been used extensively as a model enzyme for investigating the relations between structure, dynamics, and function in proteins. The researchers found that, at each stage in the catalytic cycle, the excited-state conformations resembled the ground-state structures of both the preceding and the following intermediates. This means that the dynamic fluctuations between the ground state and the excited state were "priming" the enzyme to take up the conformation of the adjacent intermediate state, facilitating the progress of catalysis by aiding the movement of ligands (molecules that bind to one chemical entity to form a larger complex) on and off the enzyme.
"These findings contrast with the traditional 'induced fit' hypothesis," Wright said. "One of the tenets of that hypothesis is that the binding of ligands induces a structural change that increases the complementary relationship between the ligand and the enzyme."
As the study points out, most proteins do not have rigid molecular structures but are structurally heterogeneous; the motion and plasticity in their structure allows them to achieve a far greater range of functions than would be possible with static structures.
However, despite considerable evidence that many enzymes are inherently flexible, the fundamental mechanisms by which protein fluctuations couple with catalytic function remain poorly understood.
In the new conformational model, a small number of minor conformational sub-states that resemble the ligand-bound conformations are already present in solution. When the ligand binds to the minor sub-state, it causes an equilibrium shift so that the ligand-bound conformation becomes the new major sub-state.
"Our study can be placed in the broader context of the catalytic cycle," Wright said. "The results imply that for each of the intermediates in the catalytic cycle of DHFR, the lowest energy excited states are the most functionally relevant conformations. The enzyme structure responds to ligands by taking up a preferred ground-state conformation, but also samples other relevant conformations of higher energy, enabling it to rapidly advance to the next steps in catalysis. As ligands change, the energy landscape and the accessible states of the enzyme change in response. Consequently, this dynamic energy landscape efficiently funnels the enzyme along a specific kinetic path, where the number and heights of the barriers between consecutive conformations have been minimized."
In addition to Wright, other authors of the study are David D. Boehr and H. Jane Dyson of Scripps Research, and Dan McElheny, now at the University of Chicago.
The study was supported by the National Institutes of Health, The Skaggs Institute for Chemical Biology, and the Canadian Institutes of Health Research.
The study was published in the September 15 (Volume 314, Issue 5793) edition of the journal Science.

[Preciouslife1]

Increased Risk Of Diabetes And Heart Disease From Prostate Cancer Treatment

A treatment mainstay for prostate cancer puts men at increased risk for diabetes and cardiovascular disease, according to a large observational study published in the Sept. 20 Journal of Clinical Oncology.

"Men with prostate cancer have high five-year survival rates, but they also have higher rates of non-cancer mortality than healthy men," says study author Nancy Keating, MD, MPH, assistant professor of health care policy and of medicine at Harvard Medical School. "This study shows that a common hormonal treatment for prostate cancer may put men at significant risk for other serious diseases. Patients and physicians need to be aware of the elevated risk as they make treatment decisions."

The principal systemic therapy for prostate cancer involves blocking testosterone production. This is done either by removal of the testes (bilateral orchiectomy), or more commonly, by regular injections of a gonadotropin-releasing hormone (GnRH) agonist drug. GnRH agonists are the main therapy for static prostate cancer and may also improve survival for some men with locally-advanced cancers.

However, little is known about the efficacy of GnRH agonists in treating men with less-advanced local or regional prostate cancer, many of whom receive this therapy. Earlier studies have found GnRH agonists to be associated with obesity and insulin resistance, a precursor to diabetes.

"Our study found that men with local or regional prostate cancer receiving a GnRH agonist had a 44 percent higher risk of developing diabetes and a 16 percent higher risk of developing coronary heart disease than men who were not receiving hormone therapy," says Keating, who is also a physician at Brigham and Women's Hospital.

"Doctors should think twice about prescribing GnRH agonists in situations for which studies have not demonstrated improved survival until we better understand the risks of treatment," says co-author Matthew Smith, MD, PhD, associate professor of medicine at HMS and a medical oncologist at Massachusetts General Hospital. "For men who do require this treatment, physicians may want to talk with their patients about strategies, such as exercise and weight loss, which may help to lower risk of diabetes and heart disease."

Given the number of men receiving GnRH agonists, often for many months or years, these increased risks can have important implications for the health of prostate cancer survivors, says Keating. Additional studies are needed to fully understand the biological mechanisms responsible for these increased risks.

Prostate cancer is the most frequently diagnosed cancer among men, affecting more than 200,000 men in the United States every year. With prostate cancer's favorable prognosis, however, decisions about treatments are particularly important because adverse effects and complications of treatments may impact overall health and quality of life more than prostate cancer itself.

The study assessed whether androgen deprivation therapy was associated with an increased incidence of diabetes, coronary heart disease, myocardial infarction, or sudden cardiac death by examining data from approximately 73,000 men age 66 or older who were diagnosed with local or regional prostate cancer.

###

This work was supported by the Prostate Cancer Specialized Program of Research Excellence (SPORE) of the National Cancer Institute, one of the National Institutes of Health.

[Preciouslife1]

Fatty Fish Consumption Reduces Kidney Cancer Risk By 44%

If you eat fatty fish, such as salmon or sardines, more than once a week, your chances of developing kidney cancer are 44% less than a person who does not eat fatty fish, according to researchers at the Karolinska Institutet, Stockholm, Sweden.

You can read about this study in the Journal of the American Medical Association, September 20th issue.

The 15-year study of 61,433 women compared lean fish to fatty fish consumption, and the link to renal (kidney) cancer. The women answered a questionnaire about their eating habits in 1987 and then again in 1997. They were followed up in 2004.

The following were classed as fatty fish:

-- Salmon
-- Herring
-- Mackerel
-- Lake trout
-- Sardines
-- Albacore tuna
-- Seafood (shrimps/prawns, lobster, crayfish)

The following are classed as lean fish:

Cod
Haddock
Hake
Pollock
Plaice
Lemon sole
Brill
Turbot
Black sole
Ray
Dogfish
Shark

150 women developed kidney cancer during that 15-year period (1987-2005). Women who had consumed fatty fish at least once a week were significantly less likely to develop kidney cancer than those who never ate fatty fish, said the researchers. Those who consumed lean fish at least once a week were no better off.

The researchers wrote "In this large population-based cohort with data on long-term diet, we found that women who consumed one or more servings of fatty fish per week had a statistically significant 44% decreased risk of RCC (renal cell carcinoma) compared with women who did not consume any fish. Women who reported consistent long-term consumption of fatty fish at baseline and 10 years later had a statistically significant 74 percent lower risk."

The researchers concluded that frequent consumption of fatty fish may lower renal cell cancer risk as a result of a higher intake of eicosapentaenoic acid and docosahexaeneoic acid as well as vitamin D (all found in abundance in fish oils).

Fatty fish have much higher levels of omega-3 fatty acids and vitamin D than lean fish, said the scientists.

It is estimated that there will be about 208,500 cases of kidney cancer worldwide this year, and 101,900 kidney cancer deaths. In the USA there are estimated to be 39,000 new cases this year, and 10,700 deaths (International Agency for Research on Cancer and the American Cancer Society).

Long-term Fatty Fish Consumption and Renal Cell Carcinoma Incidence in Women
Alicja Wolk, DMSc; Susanna C. Larsson, MSc; Jan-Erik Johansson, MD, PhD; Peter Ekman, MD, PhD
JAMA. 2006;296:1371-1376.

Written by: Christian Nordqvist
Editor: Medical News today

[Preciouslife1]

The most aggressively malignant cancer cells have a "toggle switch" that enables them to morph into highly mobile cells that invade other tissues and then nest comfortably in their new surroundings, a new study in rats suggests.

This picture of how cancer cells shift between two alternating states -- travelers and nesters -- represents a new understanding of how cancer metstasizes, or spreads to other parts of the body, said the Duke Comprehensive Cancer Center researchers who conducted the study.

"Understanding this toggle switch might ultimately enable scientists to find ways to stop cells from metstasizing, which is the most deadly trait of cancer," said the study's lead investigator, Mariano Garcia-Blanco, M.D., Ph.D., professor of molecular genetics and microbiology.

The researchers publish their findings in the Sept. 19, 2006, issue of the journal Proceedings of the National Academy of Sciences, now available on line. The research was funded by the National Cancer Institute.

Until now, scientists have believed that cancer cells must transform permanently from stationary epithelial cells into migratory mesenchymal cells in order to
The Duke team discovered that highly malignant cells are equal parts epithelial and mesenchymal, transitioning between the two as their surroundings necessitate. The proteins that the cell produces dictate which way the cell shifts.

In a classic example of survival of the fittest, a cancer cell's ability to toggle between epithelial and mesenchymal enables the most malignant cells to aggressively invade and then peacefully adapt in unfamiliar territory, the scientists said.

"The prevailing notion has been that the more mesenchymal the cancer cells, the more mobile and static they would be," Garcia-Blanco said. "In reality, aggressive cancer cells are not homogenous, but are extremely versatile in their ability to adapt as their survival needs shift."

The researchers discovered this transition in cancer cells when they observed an error in "alternative splicing," a key element of the genetic copying program inside cells. Alternative splicing determines how the DNA is chopped into pieces and then reassembled. The order in which DNA is reassembled determines which proteins the gene produces.

In cancer cells, the splicing machinery goes awry -- as do myriad functions within the cells. When the splicing process proceeds one way, the cells become mesenchymal. Spliced another way, the cells turn epithelial.

To determine which way a cancer cell would turn, the scientists constructed a fluorescent "reporter" -- a protein that illuminates if the cell turns epithelial but lies dormant if the cell reverts to mesenchymal state.

By following the reporter's illumination within cancer cells in rats, the team viewed the very process of alternative splicing as it occurred in the tumors. The researchers were able to visualize specific portions of DNA, called exons, to see if they were included or excluded in the splicing process as the cell transformed.

"We found that the regulation of alternative splicing is different in mesenchymal versus epithelial cells," Garcia-Blanco said. "A particular exon, FGFR2 IIIc, is silenced in mesenchymal cells but is active in epithelial cells.

"We can visualize the genes as they are dynamically changing," he said. "We can define the cell types by observing their splicing patterns."

According to Garcia-Blanco, the cellular switch that is believed to guide the regulation of splicing is a protein called Fox. Both mesenchymal and epithelial cells produce Fox, but the protein is active only in epithelial cells, Garcia-Blanco said.

Fox also may have an accomplice or "co-factor" in or around epithelial cells that prompts it to activate, the researchers said. They speculate that this co-factor could be activated by contact with stroma --the supporting structural cells of a tumor -- because the stroma is where the majority of epithelial-type cancer cells were observed. Their heavy presence implies that the stroma may have induced the cancer cells to revert to epithelial when they reached a new destination, so they could stabilize to populate a new tumor site.

"Our findings validate that tumors are highly complex in their behavior and don't necessarily need a gene mutation to alter their behavior," said Sebastian Oltean, M.D., Ph.D., research associate and first author of the journal article.

"Alterations in gene splicing can be much more subtle in nature but still have a major impact on the cancer cell and can be targets of therapy."

The team's next step is to determine precisely what controls the toggle mechanism in cancer cells, Garcia-Blanco said. Identifying the various steps that occur during the natural progression of tumors could lead to therapies for blocking I
###

Contact: Rebecca Levine
Duke University Medical Center

[Preciouslife1]

OXiGENE Announces Publication in the Journal Science of Results Showing Combination Therapy with Vascular Disrupting Agents (VDAs) and an Antiangiogenic Drug Markedly Suppresses Tumor Regrowth in an Animal Model
Thursday September 21

WALTHAM, Mass.--(BUSINESS WIRE)--Sept. 21, 2006--OXiGENE, Inc. (NASDAQ: OXGN, XSSE: OXGN) today announced the publication of the results of a preclinical study evaluating the combination of vascular disrupting agents (VDAs) with an antiangiogenic drug to enhance suppression of tumor growth in mice, which appears in today's issue of the journal Science. Using an antiangiogenic drug, DC101 (ImClone Systems, Inc.), 24 hours prior to administration of either of OXiGENE's VDAs, Combretastatin-A4 phosphate (CA4P) or OXi-4503, resulted in markedly enhanced anti-tumor activity in the study.

VDAs such as OXiGENE's CA4P and OXi-4503 have been shown to cause rapid occlusion of existing tumor blood vessels which leads to massive intratumoral necrosis. However, VDA-treated tumors can regrow in the tumor periphery. This regrowth is thought to be caused in part by an acute mobilization of circulating endothelial progenitor cells (CEPs). Antiangiogenic drugs, such as DC101, inhibit growth of new blood vessels and disrupt the acute mobilization and levels of CEPs. Dr. Kerbel, a Canada Research Chair and a Professor in University of Toronto's Department of Medical Biophysics and Department of Laboratory Medicine and Pathobiology, led the team investigating the mechanistic basis for combining these two classes of agents. His team hypothesized that a rapid, reactive mobilization of CEPs to the viable tumor rim, during or after VDA treatment, might contribute to tumor regrowth and that adding an antiangiogenic agent would mitigate this effect. His study results indicate that prevention of the spike in circulating endothelial progenitor cells (CEPs) by antiangiogenic drugs or genetic manipulation resulted in markedly enhanced VDA antitumor activity.

Dr. Kerbel commented, "Because vascular disrupting drugs like CA4P and OXi4503 are known to preferentially target areas of tumors that are much less susceptible or even resistant to other anti-cancer therapies, including chemotherapy, radiation therapy, and antiangiogenic therapy, they would seem particularly ideal for combination treatments with these therapies - for which there is growing preclinical evidence. We believe that our results now provide a mechanism to explain the basis for the superior potential efficacy of such a combination involving an antiangiogenic drug with a vascular disrupting agent."

"We believe the findings from this study are of enormous importance, and will drive the intelligent development of our VDAs going forward. The publication of these results is particularly timely in light of our ongoing clinical trial combining CA4P and Avastin," said Richard Chin, M.D., President and Chief Executive Officer of OXiGENE, Inc.

[Preciouslife1]

Toward Cracking The Mystery Of Disease-fighter QS-21A

Scientists are set to publish the first detailed account of their synthesis of a remarkable molecule that improves the immune system's ability to battle disease.

Called QS-21A, it has been used in more than 80 clinical trials of therapeutic vaccines against melanoma, breast cancer, small cell lung cancer, HIV and malaria.
Unlike more familiar vaccines used to prevent disease, therapeutic vaccines treat disease that already has occurred. QS-21A is added to therapeutic vaccines as an adjuvant, or booster that enhances the vaccine's effects. QS-21A makes vaccines more potent, and allows some to be effective at lower doses.
QS-21A's effects have been known for 80 years. However, the substance previously was available in limited quantities because it had to be extracted from the bark of a South American tree.
In 2005, however, David Y. Gin and colleagues at the University of Illinois at Urbana-Champaign synthesized QS-21A.
In their latest report, scheduled for the Aug. 30 issue of the Journal of the American Chemical Society, the researchers provide key information that should enable scientists to make analogues, or molecular variants of QS-21A. That research may help solve the mystery of how QS-21A works, Gin said, and why it is so potent. Some of the new analogues could be even more effective.
Reference: "Synthetic Studies of Complex Immunostimulants from Quilaja saponaria: Synthesis of the Potent Clinical Immunoadjuvant QS-21Aapi." Journal of the American Chemical Society.

[Preciouslife1]

Successful investors no doubt get lucky once in a while.

But any good investor will tell you that relying on lady luck to grace you with her presence is about as prudent a move as hiring Tom Cruise to act as spokesman for your new line of antidepressants.
Good investors are constantly learning, changing and, most of all, working hard.
That's doubly true in the biotech space -- a sector, it seems, with as many variables as there are companies.
Sam Isaly, managing partner and founder of asset management firm OrbiMed and longtime portfolio manager of the Eaton Vance Worldwide Health Science fund, has been at it for nearly 40 years, since starting his career as a pharmaceuticals analyst with Chase Manhattan Bank.
He, for years, has manned the helm of the Eaton Vance fund, as well as managed a hedge fund and three venture capital funds (all dedicated to health care) under the OrbiMed banner.
Isaly invests primarily in the biotech sector because "we focus on new things."
Even when Big Pharma was most attractive to the New York-based manager, he says, "investment success always depended on new products."
Isaly breaks the sector into two categories -- discovery and distribution.
While some large pharmaceutical companies like Pfizer still engage in discovery, Isaly says "the bulk of their value is as a distribution company." The discovery companies are the most attractive to Isaly, whose mutual fund sports an impressive 12.6% annualized return over the past 10 years, beating the S&P 500 by 370 basis points.

The fund's top holdings consist of profitable large-cap names including Genentech, Amgen ,Genzyme,and MedImmune.

Those four names alone make up 21% of the entire portfolio as of June 30.
The mutual fund is designed to be more conservative than the hedge fund, so it sports fewer early-stage companies.
Nevertheless, Isaly expects strong growth from his roster of biotech giants.
"The outlook for those companies that are now profitable is strong for the next decade," he says. "At the moment, they're growing 20% per year, and we expect that to extend for a while."
But it's not just the household names that make their way into OrbiMed's list of holdings: Gen-Probe accounts for 7% of the portfolio and Vertex Pharmaceuticals for 4%.

The Voodoo They Do:

Isaly and his team of 10 analysts (five of whom are scientists) go through a laborious process of tracking every compound that is currently in human trials.
They consult with industry and Washington contacts, and come up with an estimated value for each of those compounds.
Next, the analysts create a projection for what the company has to spend to get to cash-flow positive and add that to the market cap. They then consider if the company will likely have to partner with a larger firm or raise money, and make a decision on whether the current value is attractive. Buy and sell decisions are often determined by events such as clinical trials.

[Preciouslife1]

For example, in May of last year, Vertex released positive phase Ib data on its hepatitis C protease inhibitor VX-950.
In the trial, the drug was found to greatly reduce the amount of virus in patients. That was enough for Isaly to pull the trigger and buy the stock in the midteens.
Today, Vertex is above $32 after hitting a high of $44.49 in March. "We were immediately inclined to believe it's effective," he reminisces. The safety issue, however, was not in the bag due to the lack of data. Now, Isaly is more confident of the safety profile as well.
But the life of a biotech fund manager is not all popping champagne corks; the occasional implosion happens even to the best of them.
OrbiMed owns Adolor, which got cut in half recently after failing clinical trials.
Blowups will happen, Isaly acknowledges, "but we do our best to avoid them."
That said, Isaly distributes the risk in his portfolios accordingly and doesn't heavily weigh his sheets with risky names.
He also isn't giving up on Adolor, which reported two out of three studies for intestinal obstruction treatment Entereg did not meet primary endpoints.
But Isaly reminds investors that a trial failure does not necessarily mean doom for a new drug. Adolor isn't the first biotech stock to give him trouble. "We've had other problem children in our life," he readily admits. "We do think Adolor will get it together and eventually succeed."

Trend-Watching

The dominant themes in biotech these days are cancer and diabetes therapies. But Isaly doesn't quite see it that way.

"Cancer is overblown," Isaly professes. "There are too many candidates out there. There are not enough ill people for all of these candidates. It will be highly competitive if everything works."
Diabetes, on the other hand, is an area he finds intriguing.
Isaly believes DPP4 inhibitors are game-changing technologies. He particularly likes Merck's Januvia and Novartis' ( Galvus, which are taken orally. He expects both to be multibillion dollar products.
Amylin Pharmaceuticals' Byetta and Symlin are both injected and, therefore, less attractive than other treatments, according to the fund manager.
While Isaly and his team have a plethora of resources at their disposal, he says the individual investor can still succeed in the space -- but it's not easy.
"They have to be luckier than we are," Isaly says. According to the most recent filings, OrbiMed owns more than 100 stocks, including all names in this story, with the exception of Merck.

[Preciouslife1]

Charles River Laboratories Awarded $111.6 Million National Cancer Institute Contract
Friday September 22, 2006..Charles River to Construct New Facility in Support of NCI and RMS Geographic Expansion
WILMINGTON, Mass.--(BUSINESS WIRE) Charles River Laboratories International, Inc., today announced that it has been awarded a ten year, $111.6 million contract by the National Cancer Institute (NCI), more than doubling the size of its current contract with NCI. For the last twelve years, Charles River has provided onsite staffing support to NCI's Frederick Cancer Research and Development Center (FCRDC), and this award expands and strengthens that collaboration by converting the current onsite staffing contract into a long-term dedicated space agreement. In support of the new contract, Charles River will construct a shared-use facility to provide research model production and related services to NCI-FCRDC, addressing NCI's current and future research support needs.
The new, state-of-the-art shared-use facility will be constructed in close proximity to NCI-FCRDC's current operation in Frederick, Maryland, and Charles River expects construction to be completed in the third quarter of 2008. The portion of the shared facility dedicated to meeting NCI-FCRDC's support needs will be staffed and operated by Charles River's Consulting and Staffing Services (CSS) group. CSS, a growing business within Charles River, offers recruitment, training, staffing and management services to customers using Charles River personnel to staff customers' facilities or space in Charles River facilities dedicated to specific customers. To support this new contract, Charles River will dedicate an 80-person staff who will collaborate with NCI-FCRDC in providing genetically defined, pathogen-free, mice to support NCI/NIH (National Institutes of Health) funded research targeting the causes and treatments of infectious diseases, ********************bolic diseases, cancer, bioterrorism threats and other nationally recognized health issues.
Under the terms of the new contract, Charles River will also assume responsibility for the management of the NCI/NIH Tumor and Natural Products Repositories, in support of the Developmental Therapeutics Program. These Repositories store a wide array of tumor and other samples under carefully controlled conditions so that they can be made available to researchers who are exploring the causes and treatment of cancer and other diseases.
The portion of the shared-use facility not dedicated to NCI will be occupied by Charles River's Research Models and Services (RMS) business, which will use this new space as a platform for growth in the Baltimore/Washington geographic market. This represents another significant step in Charles River's ongoing strategy to situate RMS production facilities in close proximity to targeted markets, and to make an increasingly broad range of Research Model Services easily accessible to customers.
"We are pleased to have the opportunity to extend and expand our collaboration with NCI-FCRDC and to dedicate a significant portion of this new facility to supporting NCI's future research needs," stated James C. Foster, Charles River's Chairman, President and Chief Executive Officer. "I am confident that our 60 years of experience in constructing and managing highly efficient, state-of-the-art research model facilities will be a meaningful contribution in advancing the government's research mission. I am equally confident that the construction of this new shared facility will provide significant opportunities for our Research Models & Services business to increase its presence in this targeted market." This project will be funded in whole or in part with federal funds from the National Cancer Institute, National Institutes of Health, and Department of Health and Human Services under contract no. HHSNZ611200612001C

[Preciouslife1]

Proline oxidase activates both intrinsic and extrinsic pathways for apoptosis: the role of ROS/superoxides, NFAT and MEK/ERK signaling


Abstract

Proline oxidase (POX), often considered a 'housekeeping enzyme' might play an important role in apoptosis. We have shown that POX generated proline-dependent reactive oxygen species (ROS), specifically superoxide radicals, and induced apoptosis through the mitochondrial (intrinsic) pathway. In our current report, we used DLD-1 colorectal cancer cells stably transfected with the POX gene under the control of a tetracycline-inducible promoter and found POX-stimulated expression of tumor necrosis factor-related apoptosis inducing ligand (TRAIL), DR5 and cleavage of caspase-8. Importantly, apoptosis measured by flow cytometry was partially inhibited by Z-IETD-FMK, a specific inhibitor of caspase-8. These findings suggest that the extrinsic (death receptor) pathway also is activated by POX. Furthermore, the mechanism of this effect on the extrinsic pathway, specifically, the induction of TRAIL by POX, may be mediated by NFAT transcription factors. Additionally, POX expression also dramatically decreased phosphorylation of MEK and ERK, and the decrease was partially reversed by expression of manganese superoxide dismutase (MnSOD). Overexpression of constitutively active form of MEK, acMEK, partially blocked POX-induced apoptosis. These findings suggest the involvement of MEK/ERK signaling and further confirm the role of ROS/superoxides in POX-induced apoptosis. Combined with previously published data, we conclude that POX may induce apoptosis through both intrinsic and extrinsic pathways and is involved in nuclear factor of activated T cells (NFAT) signaling and regulation of the MEK/ERK pathway. It is suggested that, as a nutrition factor, POX may modulate apoptosis signals induced by p53 or other anti-cancer agents and enhance apoptosis in stress situations.
Keywords:

proline oxidase, apoptosis, superoxide radicals, NFAT, ERK, ********************bolism

Abbreviations:

Ad, adenovirus; Dox, doxycycline; DR5, death receptor 5; MnSOD, manganese superoxide dismutase; MOI, multiplicity of infection; NFAT, nuclear factor of activated T cells; P5C, pyrroline-5-carboxylate; PBS, phosphate-buffered saline; PIG, p53-induced gene; POX, proline oxidase; ROS, reactive oxygen species; TRAIL, tumor necrosis factor-related apoptosis inducing ligand

Y Liu1, G L Borchert2, A Surazynski1, C-A Hu3 and J M Phang1

1. <LI id=aff1 minmax_bound="true">1********************bolism and Cancer Susceptibility Section, Laboratory of Comparative Carcinogenesis, Center for Cancer Research, National Cancer Institute, Frederick, MD, USA <LI id=aff2 minmax_bound="true">2Basic Research Program, SAIC-Frederick, Inc., Frederick, MD, USA
2. 3Department of Biochemistry and Molecular Biology, University of New Mexico Health Science Center, Albuquerque, NM, USA

Correspondence: Dr Y Liu or Dr JM Phang, ********************bolism and Cancer Susceptibility Section, Laboratory of Comparative Carcinogenesis, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702, USA. E-mail: liuy@ncifcrf.gov or phang@ncifcrf.gov
Received 2 December 2005; Revised 1 March 2006; Accepted 1 March 2006; Published online 17 April 2006.

[Preciouslife1]

Tumour suppressors: End of the old guard?

Nicola McCarthy
The 'guardian of the genome', p53, rapidly induces both cell-cycle arrest and apoptosis in response to DNA damage, thereby preventing mutated cells from becoming tumours. This dogma is challenged by results from Gerard Evan and colleagues and Manuel Serrano and colleagues, who show that these early responses can be dispensed with and that the stabilization and activation of p53 through the oncogene-mediated activation of the tumour suppressor p19ARF is crucial for tumour suppression.

Exposure of p53 wild-type mice to -radiation induces widespread p53-mediated apoptosis in radiosensitive tissues, and these mice are significantly protected from lymphomagenesis compared with p53-deficient mice. Evan and colleagues had previously constructed a p53 knock-in mouse in which the function of p53 is regulated by the addition of 4-hydroxytamoxifen (4-OHT). p53 is not activated by this treatment, but is merely rendered ready for action. They used these mice to determine when p53 needs to function in order to suppress lymphoma development in response to -radiation.
p53 knock-in mice were treated with 4-OHT or sham treated for 6 days before treatment with 2.5 Gy of total body -radiation. The mice treated with 4-OHT showed classical p53-mediated responses, including apoptosis in the lymphoid tissue and intestinal epithelium — the sham treated mice were devoid of these pathologies. These 2 groups of mice were then monitored for the onset of lymphoma. Surprisingly, the mice that were initially treated with 4-OHT prior to radiation showed no protection from lymphomagenesis compared with the sham treated mice, indicating that the widespread p53-mediated apoptosis seen in the lymphoid compartment after radiation did not protect from lymphoma development. As global DNA damage was resolved with identical kinetics in both wild-type and p53 knock-in mice treated with 4-OHT, the authors investigated whether p53 needs to function later to suppress tumours after the initial DNA damage has been resolved. p53 knock-in mice were irradiated as before, but this time p53 was not restored until 8 days after radiation treatment. These mice showed no signs of radiation-induced pathologies and were significantly protected from lymphomagenesis.
So, if the early p53-dependent response to DNA damage is not required, how does p53 function as a tumour suppressor? In theory, the initial radiation insult might result in unresolved DNA damage that persistently triggers p53 activation, or it might result in oncogenic mutations that activate p19ARF, which in turn activates p53. Importantly, p19ARF is only activated in response to oncogene activation and not DNA damage. The authors crossed Arf-deficient mice with p53 knock-in mice and exposed these mice to -radiation followed by the restoration of p53 function 8 days later. These mice showed no protection against lymphoma development. This result indicates that the p19ARF–p53 pathway is crucial for tumour suppression. The authors suggest that p19ARF is activated in pre-lymphoma cells by oncogenic mutations induced as a result of exposure to -radiation.
A similar conclusion has been reached by Serrano and colleagues. They treated Arf-null mice that express one extra physiologically regulated copy of the Trp53 gene (p53super mice) or are wild type for p53 with either -radiation or a DNA-damaging carcinogen, or simply analysed the incidence of spontaneous tumour development. All of the Arf-null mice had a normal p53 DNA-damage response, but could not activate p53 in response to the deregulated expression of an oncogene. p53super mice are known to be more resistant to tumour formation, but this was not the case in the p53super/ARF-null mice. These mice developed tumours at an identical rate to p53 wild-type/ARF-null mice, showing that the protection afforded by p53 against tumour development is ARF dependent.
These data are consistent with other studies that question whether the early response to DNA damage is essential for p53 to function as a tumour suppressor, and further support the key function of the p19ARF pathway in suppressing tumour development.

References and links

ORIGINAL RESEARCH PAPERS

1. <LI id=B1 minmax_bound="true">Christophorou, M. A. , Ringhausen, I. , Finch, A. J. , Brown-Swigart, L. & Evan, G. I. The pathological response to DNA damage does not contribute to p53-mediated tumour suppression. Nature 443, 214–217 (2006)
   • Article
   • ChemPort
2. Efeyan A . et al. Policing of oncogene activity by p53. Nature 443, 159 (2006)

[Preciouslife1]

Angiogenesis: Sneaky switch

Edward Wawrzynczak

Solid tumours contain both transformed cells and non-neoplastic cell types such as macrophages and neutrophils, which have been shown to increase the invasive and ********************/static properties of tumour cells and to promote tumour growth. Now, Douglas Hanahan and colleagues have shown that tumour formation in a transgenic mouse model of multistage carcinogenesis is promoted by tumour-infiltrating neutrophils that activate angiogenesis.
RIP1–Tag2 mice, which express the simian virus 40 (SV40) large T antigen (Tag) under the control of the rat insulin promoter 1 (RIP1), develop angiogenic dysplasias and, subsequently, tumours of the pancreatic islets. Previous studies showed that an important trigger of angiogenesis in this model is matrix ********************/lloproteinase 9 (MMP9), which seems to function by increasing the availability of the pro-angiogenic vascular endothelial growth factor (VEGF). However, in this model the tumour cells do not express MMP9.
So, to identify the non-tumour cells that express MMP9, the authors compared normal and neoplastic pancreatic tissues using double-label immunohistochemical staining of MMP9 and leukocyte cell-specific markers. Neutrophils were the only MMP9-positive cells found within islet lesions, and were therefore the prime candidates for MMP9-mediated activation of angiogenesis. The next step was to show the functional involvement of neutrophils in vivo.
Giving a neutrophil-depleting antibody to young RIP1–Tag2 mice, in which neutrophil infiltration and angiogenic switching occurs in hyperplastic lesions, halved the number of angiogenic islets compared with mice that received a nonspecific antibody. This effect was similar to either administering an MMP9 inhibitor or deleting the Mmp9 gene, which indicates that neutrophils are the main cell type responsible for angiogenic switching. Antibody-mediated neutrophil depletion reduced the presence of VEGF–VEGF receptor complexes on the endothelial cells of angiogenic islets by sevenfold, consistent with the expected molecular mechanism of switching.
These findings show that infiltrating neutrophils have a key role in switching on angiogenesis during the early stages of pancreatic tumour development. Establishing whether neutrophils have a similar role in the early progression of other animal and human tumours and identifying the mechanisms that sustain angiogenesis after it has been switched on are important next steps.

References and links

ORIGINAL RESEARCH PAPER

1. Nozawa, H. et al. Infiltrating neutrophils mediate the initial angiogenic switch in a mouse model of multistage carcinogenesis. Proc. Natl Acad. Sci. USA 103, 12493–12498 (2006)

[Preciouslife1]

Viral Tumorigenesis: Viral hijacking

Francesca Pentimalli
Despite its association with tumours and unlike other DNA viruses, human cytomegalovirus (HCMV) does not transform cells, so how it exerts its oncogenic potential has been unclear. Martine Smit and colleagues now show that US28, an HCMV gene that encodes a G-protein-coupled receptor, is important for initiating angiogenesis in transformed cells.
The US28 receptor is a homologue of the human chemokine receptor CCR1 but, unlike its cellular counterpart, it signals in a constitutively active manner and has previously been shown to activate pathways that lead to cell proliferation and migration.

HCMV might use US28 to hijack several signalling networks within infected cells. In fact, this viral receptor displays promiscuous G-protein coupling that causes the constitutive activation of different G proteins and potentiates the signalling of other cellular chemokine receptors.
Smit and colleagues found that when US28 is stably expressed in NIH-3T3 cells, the cells have an increased growth rate that results, at least in part, from the increased expression of cyclin D1. The US28-expressing cells also form foci in vitro, and after 5 days the cells express high levels of vascular endothelial growth factor (VEGF) compared with cells that express a mutant US28 that is unable to bind G proteins. To further dissect the pathway activated by US28, the authors investigated the downstream signalling pathways and found that US28 signals through both Gq and G protein subunits and two different MAPKs (mitogen activated protein kinases) to stimulate downstream transcription factors, which ultimately lead to VEGF promoter activation. Consistent with this, NIH-3T3 cells that expressed US28 formed highly vascularized, VEGF-expressing tumours 2 weeks after inoculation into nude mice. This indicates that VEGF-mediated angiogenesis is responsible for at least some of the oncogenic properties of US28.
To verify these findings the authors used an HCMV strain that does not express US28 to infect a glioblastoma cell line. This strain failed to induce VEGF promoter activation, unlike the wild-type virus.
Interestingly, the expression of US28 in non-tumorigenic cells can also induce apoptosis. So, it seems that the cellular context determines whether US28 functions as an oncogene and a pro-angiogenic factor. The authors conclude that US28 might be a potential target for the treatment of early-stage HCMV-related proliferative diseases.


References and links

ORIGINAL RESEARCH PAPER

1. Maussang, D. et al. Human cytomegalovirus-encoded chemokine receptor US28 promotes tumorigenesis. Proc. Natl Acad. Sci. USA 103, 13068–13073 (2006)

[Preciouslife1]

Armed T cells attack cancer

A study published in Science has provided the first direct evidence that genetic modification of a patient's own T cells can be used to fight tumours. This treatment has led to tumour regression in two men dying of advanced skin cancer (ScienceXpress, 31 August 2006).
The trial, based at the National Cancer Institute (Bethesda, Maryland) and headed by Steven Rosenberg, involved 17 patients with advanced me.tastatic melanoma that had proved unresponsive to standard therapies. In two patients, "The tumors went away, and both of the patients are now completely disease-free over a year and a half later", said Rosenberg (nytimes.com, 1 September 2006).
Previous attempts at cancer immunotherapy have relied on the transfer of tumour-infiltrating lymphocytes following ex vivo expansion, but these cells are often difficult to isolate and identify. So Rosenberg and colleagues isolated T cells from the blood of the 17 patients and infected them with retroviral vectors encoding T-cell receptors that specifically recognize melanoma-associated antigens. This modification was designed to increase the cancer-detecting abilities of the T cells when infused back into the patients. The study reports that the genetically engineered T cells persisted in 15 patients, making up at least 10% of circulating T cells 2 months after treatment (ScienceXpress, 31 August 2006).
This approach is one of only a few published successes in the field of gene therapy, a troubled field that has been hindered by safety concerns, including the development of leukaemia in patients with severe immunodeficiency who were participating in a gene-therapy trial in France in 2002. However, cancer expert Thomas Gajewski, at the University of Chicago (Illinois), told New Scientist that the risk of such a complication in the melanoma trial is slim "because [the treatment] involves inserting genes into mature immune cells, which are less likely to multiply uncontrollably than the stem cells that were genetically altered in the French trial." (NewScientist.com, 31 August 2006). Nevertheless, experts in gene therapy expressed cautious optimism. Michel Sadelain, of the Memorial Sloan-Kettering Cancer Center (New York), said, "This certainly is a significant technical advance that is going to fuel more interest... [but] The response here is rather disappointing." (nytimes.com, 1 September 2006); 15 patients failed to respond to the treatment.
The researchers suspect that the low response rate was because the expression and the function of the T-cell-receptor transgenes were not optimal; "they say they have improved their technique in the months since the trial was done" (news@nature.com, 28 August 2006).
Now, Rosenberg plans to test the approach against other forms of cancer; "We have now expressed other lymphocyte receptors that recognise breast, lung, and other cancers" (Telegraph.co.uk, 1 September 2006). At present, he is awaiting approval to use cells that express these receptors in new trials in patients with other types of cancer (Reuters.com, 31 August 2006).


Lucy Bird1 Author affiliations

1. Associate Editor, Nature Reviews Immunology