Wednesday, August 19, 2009

Powerful anti-cancer compound uncovered (in mice)

Many effects found in rodents do not generalize to humans

A new study conducted on mice has uncovered a chemical compound that effectively targets cancer stem cells - the key cells that spread malignant tumors and are usually resistant to treatment. In a study published in Thursday's edition of the journal Cell, a group of medical researchers said they had discovered that a compound called salinomycin directly targeted cancer stem cells. "Evidence is accumulating rapidly that cancer stem cells are responsible for the aggressive powers of many tumors," said Robert Weinberg, a member of the Whitehead Institute for Biomedical Research, and one of the study's authors.

Cancer stem cells are rare but aggressive parts of tumors and their ability to seed new tumors while proving largely resistant to chemotherapy and radiotherapy makes them a key component in treating cancer patients. "Many therapies kill the bulk of a tumor only to see it regrow," said Eric Lander, director of the Broad Institute of the Massachusetts Institute of Technology and Harvard University, another author of the Cell paper.

Previous attempts to study cancer stem cells have been stymied by difficulties in locating the rare cells within tumors, and the tendency of the cells to lose their key properties when grown outside of the body. To conduct their research, the study group found a novel way to manipulate cultured breast cancer cells into cancer stem cells that retained the tendency to seed tumors and resist anti-cancer treatments. The researchers then analyzed some 16,000 chemical compounds, looking for one that could target the cancer stem cells, eventually narrowing the field to 32, and then down to one: salinomycin.

The compound showed impressive results, both against naturally-occurring and manipulated cancer stem cells, reducing the proportion of breast cancer stem cells by more than 100-fold compared to a commonly-used breast cancer treatment called paclitaxel. It also inhibited the ability of the cancer stem cells to seed new tumors when injected into mice, and slowed the growth of existing tumors in the animals. "It wasn't clear it would be possible to find compounds that selectively kill cancer stem cells," said Piyush Gupta, one of the study's lead authors and a researcher at the Broad Institute. "We've shown it can be done."

The compound even targeted groups of genes, usually linked to particularly aggressive tumors and poor patient prognoses, that are highly active in cancer stem cells, effectively decreasing their activity, the study said. "Our work reveals the biological effects of targeting cancer stem cells," said Gupta. "Moreover, it suggests a general approach to finding anti-cancer therapies that can be applied to any solid tumor maintained by cancer stem cells."

The researchers are not yet sure how salinomycin works, and there are a number of pharmaceutical steps that would need to be taken before it could be used to treat cancer patients. However, the study's authors are positive both about the prospects for salinomycin and a number of the other chemical compounds tested, several of which also showed some ability to target cancer stem cells.


Always look on the bright side of life... it could help fend off a heart attack

This is just another replication of the long-established finding that hostile people have more coronary heart disease

A study of 100,000 women showed that the optimistic ones had a nine per cent lower chance of developing heart disease. The research, from the University of Pittsburgh, examined the women aged 50 to 79 who were initially free of cancer and cardiovascular disease. It revealed that those seen as having positive characters were less likely to die from conditions linked to diabetes, high blood pressure and high cholesterol or have depressive symptoms, smoke, be sedentary or have a high body mass index. But women with a high degree of 'cynical hostility' were at a higher risk of dying earlier.

Women were deemed to be optimistic if they agreed with statements such as: 'In unclear times, I usually expect the best.' Pessimism was defined as agreeing: 'If something can go wrong for me, it will.'

Lead author Hilary Tindle said: 'As a physician, I'd like to see people try to reduce their negativity in general. The evidence suggests that sustained, high degrees of negativity are hazardous to health.'

A separate study, from the University of Alberta, Canada, found that positive expectations helped patients with whiplash injuries recover three times more quickly. Those who had low expectations of complete recovery were four times more likely still to feel symptoms of the injury six months later. ... and why reading this could make you smile

According to the old song, when you're smiling the whole world smiles with you. And according to psychologists, it's true. An experiment suggested that the tendency is to smile or frown when you see someone else doing the same thing. The facial muscles are automatically activated just by observing the other person's expression, researchers from Dutch universities found. And even merely reading certain trigger words can have an effect.

The study, to be published in the journal Psychological Science, detected different facial reactions to the words 'smile' and 'cry' or 'funny' and 'frustrating'. As volunteers read the words, the researchers monitored the reaction in the zygomatic muscle which control smiles and the corrugator supercilii, controlling frowns. When they read the verb 'to laugh' from a screen, it activated the zygomatic 'smile muscle' yet when they read 'to frown' the frown muscle did not respond at all.

There was some, but not as much, movement from both the smile and frown muscles when the volunteers read the words 'funny', 'frustrating' and other adjectives.


Australia: Vaccine fear campaign investigated

These fruitcakes certainly are dangerous

A GROUP that claims vaccines cause autism, brain damage and cancer has been reported to the healthcare watchdog for allegedly spreading misinformation and endangering children's health. The official complaint to the Health Care Complaints Commission follows a newspaper advertisement paid for by businessman Dick Smith pleading with parents to ignore the Australian Vaccination Network's fear campaign.

AVN is run by Meryl Dorey, who publishes a website and newsletter, campaigns against mass public immunisation programs and promotes the use of homeopathy to prevent disease.

The Australian Skeptics group supports the complaint that Ms Dorey and the network are breaching the Health Care Complaints Act by making unsubstantiated health claims based on "conspiracy theories", pseudo-scientific evidence and debunked research.

Ms Dorey, of Bangalow on the Far North Coast, says her eldest son, now 20, was "vaccine-injured" from the diphtheria-tetanus-polio immunisation when he was two months old and the measles-mumps-rubella shot at 12 months. She attributes his life-long sleep apnoea and allergies to the vaccinations. Ms Dorey said she was not anti-vaccination, just "pro-information and pro-choice". "We never have and never will tell anyone that they should not vaccinate. We simply fill the information void left by government and the mainstream medical community," she said.

But Dick Smith, the Skeptics and the author of the complaint, Ken McLeod, say Ms Dorey and AVN do not promote choice because her speeches and publications never mention the proven benefits of immunisation, and the group's motto is: "Love them, protect them, never inject them.". "They can have their view but be upfront about it and don't quote dubious scientific evidence that has been debunked," Skeptics executive officer Tim Mendham said.

Mr Smith wrote and funded the advertisement because he believed young, vulnerable mothers were being conned by the network's claim to be an independent voice.

Complaints commission executive officer Kim Swan said the allegations were being assessed, and AVN had been asked to respond. Ms Dorey said the commission did not have jurisdiction over her or the network because she was not medically qualified and did not provide a health service.


No comments: