Wednesday, July 15, 2009

“Trojan Horse” Used to Terminate Cancer Cells

Scientists have long been looking for a better way to fight the battle of cancer, rather than the traditional radiation and chemotherapy treatments, both of which damage healthy cells instead of just the cancerous ones. Now, they might have found the answer with a new treatment they call the “Trojan horse” therapy.

A team of researchers in Australia have developed the new “Trojan horse” therapy to help combat cancer by using a bacterially-derived nano cell to help penetrate and disarm the cell that is cancerous before a second nano cell kills it with the chemotherapy drugs. The “Trojan horse” therapy has the potential to target the cancer cells directly with chemotherapy, rather than the current treatment where drugs are injected into the cancer patient and end up attacking both the healthy and the cancer cells.

The scientists in Sydney, Dr. Jennifer MacDiarmid and Dr. Himanshu Barhmbhatt who formed EnGenelC Pty Ltd in 2001, stated that they have achieved a 100 percent rate of survival in mice with human cancer cells by using the “Trojan horse” therapy over the past two years. They plan to start the clinical trials on humans within the coming months. However, the human trials of the cell delivery system will begin next week at The Austin located at the University of Melbourne and the Peter MacCullum Cancer Center at the Royal Melbourne Hospital.

The therapy, which was published in the latest Nature Biotechnology journal, sees the mini-cells that are called EDVs (EnGenelc Delivery Vehicle) attach and then enter the cancer cell. The first wave of these mini-cells release ribonucleic acid molecules, which are called siRNA, that are used to switch off the production of proteins that make the cancer cell resistant to the chemotherapy treatment. Then, a second wave of the EDV cells are accepted by the cancer cells and release the chemotherapy drugs, in turn, killing the cancer cell.

MacDiarmid stated, “The beauty is that our EDVs operate like ‘Trojan horses’. They arrive at the gates of the affected cells and are always allowed in. We are playing the rogue cells at their own game. They switch-on the gene to produce the protein to resist drugs, an we are switching-off the gene which, in turn, enables the drugs to enter.”

RNA interference, also known as RNAi, is designed to help silence the genes that are responsible for producing disease-causing proteins and is considered one of the hottest areas of biotechnology research. The subject of RNA was the basis of the 2006 Nobel Prize in medicine. Dozen of biotechnology companies are already looking for way that they can manipulate RNA to help block the genes that produce disease-causing proteins that are involved in blindness, cancer or AIDS.

Brahmbhatt said that after the treatment with the conventional drug therapy, a high number of the cancer cells are terminated, however, a small percentage of the cells can produce the proteins that make cancer cells resistant to the chemotherapeutic medications. “Consequently, follow-up drug treatments can fail. The tumors thus become untreatable and continue to flourish, ultimately killing the patient. We want to be part of moving toward a time when cancers can be managed as a chronic disease rather than being regarded as a death sentence,” he stated.

The Nature report said that the mini-cells were well tolerated by the animals that were actively treated with no adverse side effects or deaths, despite the repeated dosing. MacDiarmid said, “Significantly, our methodology does not damage the normal cells and is applicable to a wide spectrum of solid cancer types. The hope is that the benign nature of this EDV technology should enable cancer sufferers to get on with their lives and operate normally using outpatient therapy.”

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