PARP inhibitors show promise in fight against cancer

New drugs known as PARP inhibitors are showing promise as treatment for some of the most aggressive types of breast cancer, according to recent research.

The promise could yield a brand new direction for cancer drugs, especially for those that fight breast, ovarian and prostate cancer.  The trials are in their earliest stages, but cancer specialists have been pleased with results so far “We were surprised and delighted,” Dr. Stan Kaye of the Royal Marsden Hospital in London said, “It’s the kind of thing you don’t really think will happen.”

PARP is an acronym for poly (ADP-ribose) polymerase. PARP is a protein that has several roles in cellular processes, most notably in DNA repair and programmed cell death. Healthy cells can use PARP to repair themselves and live out their normal life cycle. But cancer cells may also use PARP to repair DNA damage, thus extending their uncontrolled growth. Such cancers can become resistant to treatment. There are several different PARP proteins, and they each have their own role in functions within cells.

A PARP inhibitor is a drug that blocks PARP proteins from performing their roles in repairing damaged cancer cells. Chemotherapy and radiation work by breaking the DNA of cells so that they may not reproduce. Some types of cancer cells use PARP enzymes to repair their DNA damage and recover from the assault of cancer treatments. Clinical trials are being done to see if PARP inhibitors, in combination with other cancer treatments, can block PARP protein from damaged cancer cells.

If a PARP inhibitor is added to chemotherapy treatments for breast cancer, researchers hope cancer cells that have resisted anticancer drugs will be become vulnerable to fatal DNA damage. In some cases, a PARP inhibitor may be used alone, rather than in conjunction with chemo and radiation. Even better news is that PARP inhibitors do not appear to affect normal, non-cancerous cells. That means fewer side effects for patients and faster recovery from treatments.

 The addition of PARP inhibitors to the current arsenal of weapons against breast cancer looks very promising. PARP inhibitors increase the effectiveness of chemotherapy against aggressive hereditary and triple-negative breast cancers, potentially without adding many serious side effects. These drugs appear to improve quality of life as well as extend survival for patients. Fighting breast cancer at the level of its DNA looks like the wave of the future.