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Showing posts with label Nobel Prize 2015. Show all posts
Showing posts with label Nobel Prize 2015. Show all posts

Wednesday, November 4, 2015

Correcting DNA mistakes

Using the knowledge of how the cell repair systems work will open the door to more effective cancer treatments



UNDERSTANDING how our cells repair damaged DNA, a breakthrough which earned the Nobel Chemistry Prize recently, could make cancer treatment more effective, experts say.

By revealing how our cells automatically fix DNA mutations which can lead to illness, the discovery opened the door to significantly improving chemotherapy’s effectiveness against cancer, which kills some eight million people worldwide each year.

“You can use this knowledge to destroy cancer,” said Nora Goosen, a DNA repair expert at Leiden University in the Netherlands.

Chemotherapy attacks cancer cells by trying to scramble their genetic code and thus their ability to multiply, but cancer cells, just like healthy ones, do not give up without a fight.

he cell repair systems are going to try to undo the work of doctors by fixing the damage the doctors were trying to inflict,” said Terence Strick, a DNA repair researcher at the Jacques Monod Institute in Paris.

One solution would be to inhibit the ability of cancerous cells to self-mend.

“If you attack these repair mechanisms (in cancer cells) in combination with chemotherapy and other drugs ... it (treatment) can be more effective,” Goosen said.

Sweden’s Tomas Lindahl, Paul Modrich of the United States and Turkish-American Aziz Sancar were awarded the top chemistry award for unravelling the process by which our cells repair mutations caused to DNA by the Sun or carcinogenic substances found in alcohol and cigarettes, for example.

Mistakes in DNA, the chemical code for making and sustaining life, can cause cells to malfunction, age prematurely, and become cancerous.

The vast majority of changes to our DNA are immediately corrected, but some accumulate and lead to cancer. Some people are more susceptible to cancer because their DNA repair response is faulty.

Ironically, the same repair mechanism identified by the Nobel laureates can also cause cancerous cells to resist the effects of cancer treatment.

Alan Worsley, a spokesman for the charity Cancer Research UK, said new drugs are being developed to fight the disease.

He cited the treatment olaparib, which stops cancer cells from fixing DNA damage. It was approved by the European Commission in December 2014 for use in Europe.

Alain Sarasin of France’s CNRS research institute highlighted the risks of interfering with DNA repair systems.

“We don’t yet know how to target tumour cells specifically. If we gave a patient a molecule which inhibits the self-repair mechanism of cancer cells, it may also inhibit the repair systems of other cells like white blood cells,” he said.

“If, one day, we have a molecule which reinforces the DNA repair and can be targeted to blood cells, for example, followed by chemotherapy after, this would allow us to increase the chemotherapy dosage without unintentionally killing blood cells.

“For now, we don’t know how to do that.” – AFP

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Friday, October 9, 2015

Nobel Prize for Chinese traditional medicine expert who developed malaria cure

Developed for Communist troops fighting in the Vietnam War, Tu Youyou's treatment was major breakthrough in global fight against malaria

Tu Youyou, right, working with Prof Lou Zhicen in the 1950s (Xinhua via AP)



A Chinese scientist who pioneered a malaria treatment for Communist troops fighting America in the Vietnam War has won the Nobel Prize for Medicine.

Tu Youyou spearheaded a secret programme set up by Chairman Mao to see if traditional Chinese herbal cures could reduce the number of North Vietnamese troops dying to malaria.

After sifting through thousands of different folk remedies, she finally unearthed a 1,600-year-old recipe using sweet wormwood that formed the basis for one of the most effective treatments ever discovered.

Under Mao's Cultural Revolution, which saw academics as part of the despised bourgeoisie, her name was kept anonymous for decades, and until recently, even colleagues had never heard of her.

Now, though, at the age of 84, she has finally taken her rightful place in world medical history, with the Nobel judges announcing on Monday that she would be a joint winner of this year's $960,000 award.

Pharmacologist Tu Youyou attends an award ceremony in Beijing in 2011 (Reuters)

The other two winners are Irish-born William Campbell and Japan's Satoshi Omura, who developed avermectin, derivatives of which are used to treat river blindness and elephantiasis.

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“The two discoveries have provided humankind with powerful new means to combat these debilitating diseases that affect hundreds of millions of people annually,” the Nobel committee said. “The consequences in terms of improved human health and reduced suffering are immeasurable.” Ms Tu's work created the drug artemisinin, which now forms part of the mainstay of malaria treatment in Africa. Used in tandem with insecticide-impregnated bednets, it is credited with helping to halve malaria mortality rates worldwide in the last 15 years.

Yet for decades, its exact origins remained unknown - as did the remarkable story of its creator, which could easily form the script for a Hollywood movie.

It begins in 1969, when Ms Tu - then a mid-career scientist - was recruited to Chairman Mao’s top-secret Project 523. Its task was to investigate cures for malaria, which in the 1960s was developing resistance to existing drugs such as chloroquine.

An illustration describing Ms Tu's work displayed during the press conference announcing the winners of the Nobel Medicine Prize (AFP)

It was also taking a heavy toll on the armies of China's communist ally, North Vietnam, who were losing more soldiers to malaria in their jungle warfare against US troops than they were to American bombs or bullets.

At the time, the quest for an effective alternative to chloroquine had baffled the world's scientific community, which had tested some 240,000 different compounds without success.

It was then that Ms Tu, who had studied both Chinese and Western medicines, began reviewing some 2,000 ancient herbal recipes from the Academy of Traditional Chinese Medicine in Beijing.

One of them, written in a 1,600 year old text called "Emergency Prescriptions Kept Up One’s Sleeve”, recommended soaking sweet wormwood in water and then drinking the resulting juice.

Tried out first on mice and monkeys, it proved highly effective, although it then had to be tested to see if was harmful of humans. As head of the research group, Ms Tu volunteered to be the first test subject herself. Subsequent trials on labourers who had caught malaria while working in dense forests proved that it could banish malarial parasites from the bloodstream within just over a day.

While such a discovery might have won Ms Tu considerable fame in the West, in Maoist-era China, she gained no kudos at all. At the time, scientist and intellectuals were viewed with suspicion at best, with Ms Tu’s husband having been banished to the countryside, and the idea of an individual scientist claiming credit for a breakthrough sat uneasily with Maoist notions of collective endeavour. Tu was not even allowed to publish her findings until 1977, a year after Mao's death, and even then, her contribution remained anonymous.

News of her work only emerged in the West when Louis Miller, an American research scientist, met Chinese scientists in 2005 and chanced to ask who had discovered artemisinin. Intrigued at the blank stares that his question produced, he began investigatingin detail.

An illustration describing the research on roundworm infections by Nobel Medicine Prize winners (AFP)

Various official paperwork - much of it once secret - revealed it to be Ms Tu, who by then was living in a shabby apartment block in Beijing. At the time, she was known by colleagues as "The Professor of the Three Nos", since she had no post-graduate degree, was not a member of any national academy, and had no foreign research experience.

While Ms Tu received America’s top medical accolade, the Lasker award, in 2011, this is the first time that any expert in Chinese traditional medicine has been awarded a Nobel.

"This is indeed a glorious moment," said Li Chenjian, a vice provost at Peking University. "This also is an acknowledgement to the traditional Chinese medicine, for the work began with herbal medicine."

Artemisinin-based drugs are now routinely used by pharmaceuticals giants like Sanofi and Novartis in the fight against malaria, which still kills half a million people a year.

It is not yet clear whether the ageing Ms Tu will attend the Nobel annual award ceremony, which takes place on December 10. Each winner will also get a diploma and a gold medal.

AT A GLANCE

Nobel Prizes 2015


Pic: AP/Fernando Vergara

Nobel Prize for Medicine

Awarded jointly for discoveries that assisted the treatment of infections caused by roundworm parasites, and Malaria
  • William C Campbell & Satoshi Omura
  • Youyou Tu

Nobel Prize in Physics

Awarded jointly "for the discovery of neutrino oscillations, which shows that neutrinos have mass"
  • Takaaki Kajita and Arthur B. McDonald

Nobel Prize in Chemistry

Awarded jointly to three people for "mechanistic studies of DNA repair"
  • Tomas Lindahl, Paul Modrich and Aziz Sancar

Nobel Peace Prize

  • To be announced 9 October

Prize for Economics Science

  • To be announced 12 October

Nobel Prize in Literature

  • Awarded to the Belarusian author Svetlana Alexievich

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