New Drug Effective Against Mesothelioma

A new drug has shown promise in the treatment of mesothelioma, a cancer of the lining of the lung that is resistant to existing chemotherapies.

The drug, called HRX9, prevents cancer cells from avoiding apoptosis. Although there are a variety of drugs that try to force apoptosis in different cancers, HRX9 is the first that is able to treat mesothelioma, according to a study published in BMC Cancer.

“Both the immune system and nearby healthy cells send signals instructing damaged and unhealthy cells to undergo apoptosis, which is like programmed 'cell suicide,'” said lead researcher Richard Morgan. “But cancer cells have developed a wide range of strategies to ignore these instructions.”

During the study, mice with human mesothelioma tumors were administered HXR9 for 3 weeks.

After 3 weeks, the tumors stopped growing and there was a complete loss of tumor blood vessels and widespread cancer cell death.

The HXR9 drugs target the HOX gene family, which has 39 similar genes that help enable the rapid cell division in growing embryos. A large portion of these genes are switched off in adults, but in many cancers, the HOX genes are switched back on, allowing cells to proliferate and survive.

“We've effectively knocked out a key defense mechanism in this cancer through targeting the HOX genes,” Morgan said.

Furthermore, the researchers discovered that mesothelioma has a strong association with the HOX gene HOXB4.

“We examined the amount of HOXB4 protein in tumors of 21 mesothelioma patients and compared it with their length of survival,” Morgan said. “There was a clear link: the more HOXB4 we found, the shorter time the patient survived, so we may also have found a way to predict which patients have the most aggressive form of this cancer.”

Mesothelioma develops from the exposure of asbestos and most patients have a year to live. However, the awareness of the dangers of asbestos has increased and researchers expect there will be a decline in new mesothelioma cases.

Unfortunately, Africa and parts of Asia still use asbestos in construction and ship building, and very few precautions are taken when buildings that contain asbestos are demolished.

“Mesothelioma may become much less of a problem in the West, but it's still going to be a significant public health problem in many parts of the world,” Morgan said. “We already know that it's resistant to available drugs, which is why we need entirely new treatments.”

“Although still early days, this study is a significant step forward in that it is the first time a drug has been observed causing so-called 'cell suicide' in mesothelioma,” added Head of Research at British Lung Foundation,” Ian Jarrold. “People living with mesothelioma often tell us that among their first reactions to diagnosis is despair at the lack of treatment available. We hope that the progress being made in research we fund will soon provide new treatments and new hope for patients.”