QUEENSLAND, Australia—Scientists from the Queensland Institute of Medical Research (QIMR) and Melbourne-based drug discovery firm Cancer Therapeutics CRC Pty. Ltd. recently announced they will collaborate on a drug based on a "super protein" found to repair damaged DNA in cancerous cells.
QIMR said it will work with Cancer Therapeutics to develop a new drug based on its recent identification of a protein known as hSSB1 that cancer cells need to survive, but normal cells can function without. The finding was detailed in a report authored by QIMR and the University of St. Andrews in the United Kingdom and published in the journal Nature.
By discovering small molecules that inhibit this protein, QIMR and Cancer Therapeutics hope to develop novel drugs that may destroy cancerous cells while leaving healthy cells intact. If successful, such drugs against this target could be a major step forward in the treatment of a whole range of different cancers, says QIMR researcher Dr. Derek Richard.
"There are many theoretical anticancer drug targets out there, but few have led to anything," Richard says. "Cancers have highly elevated levels of DNA damage and chromosomal rearrangements. The requirement of hSSB1for the repair of the damaged DNA in these cancer cells makes it a potential anticancer target."
For Cancer Therapeutics, the collaboration is its first project outside its initial core of participants, which includes several other Australian academic researchers and their institutes.
"[This project] demonstrates the attractiveness of our comprehensive drug discovery and development capabilities and our ability to work with leading researchers to bring their ideas into the world of cancer drug development," says Dr. Julian Clark, CEO of Cancer Therapeutics. "We expect that such collaborations between biological researchers and our drug developers can make a real impact on the treatment of cancer."
The research was based on Richard's study of archaea, single-cell microorganisms which live in boiling sulphuric acid pools in Iceland, one of the most extreme environments on earth. Archaea rely on hSSB1 to protect and repair its DNA, and QIMR scientists have found this protein also exists in humans.
"It was during this study that we discovered through database mining two human
SSB genes which at the time had not been annotated," Richard says. "Archaea and humans separated 3 to 3.5 billion years ago, so we knew it must be an important protein."
Richard explains that an average cell's DNA is damaged 30,000 times every day from genetic factors as well as environmental factors and exposure to toxic chemicals and UV radiation. Without hSSB1, these cells cannot repair their genes, he says.
"The next challenge is to find out how it signals that DNA is damaged, and determine if it plays a role in the development of cancer or in patients' responses to chemotherapy and radiotherapy," Richard says. "We hope soon to publish further research giving greater insight into what exactly hSSB1 is doing in cells."
Further work shows hSSB1 has potential as a cancer diagnostic prognostic marker, he adds. Richard says QIMR is seeking a commercial partner to further this research.
