Researchers found a potential way to sensitise a new subset of patients with high-grade serous ovarian carcinoma to PARP inhibitors, a promising drug used in some cases of this disease.

Ovarian carcinoma is the most lethal cancer of the female reproductive tract.

Treatments, especially for recurrent ovarian cancer patients, remain to be discovered.

Many chemotherapies function by causing damage to DNA in cancer cells, but resistance to these drugs can occur by increasing proteins, such as PARP, that play a crucial role in DNA repair.

PARP inhibitors have been found to be effective in ovarian cancer patients, especially in those patients with mutations in factors that repair DNA, like the BRCA1/2 genes.

However, treatment with these drugs has not been as effective in treating patients with normal BRCA1/2.

Due to the success of these PARP inhibitors in patients with DNA repair deficiencies, ways to utilise this promising drug in those individuals that can repair DNA effectively are currently under investigation.

Denise Connolly, PhD, associate professor in the Molecular Therapeutics Program at Fox Chase, and colleagues published a study in Cancer Biology & Therapy that examines whether a drug targeting heat shock protein 90 (HSP90), which is required for the stabilisation of factors needed in DNA repair, could provide a potential way to sensitise tumour cells to PARP inhibitors.

Connolly’s lab focuses on determining targeted therapeutics for ovarian cancer.

Her group indicated in this study that disruption of HSP90 function can lead to death of ovarian cancer cell lines without known defects in DNA repair mechanisms, such as BRCA1/2 mutations, when used in combination with a PARP inhibitor.

Targeting of HSP90 results in destabilisation of several proteins involved in DNA repair, resulting in the inability of the ovarian cancer cells to repair DNA damage.

These studies were performed both in widely available ovarian cancer cell lines as well as in novel cell lines derived from patient tumour tissue that were generated by her laboratory.

Source: Fox Chase Cancer Center