Omomyc Enhances PARP Inhibitor Effectiveness in Triple-Negative Breast Cancer

A preclinical study led by the Vall d’Hebron Institute of Oncology (VHIO) reveals that Omomyc – the first direct MYC inhibitor to complete a phase I clinical trial – boosts the impact of poly (ADP-ribose) polymerase inhibitors (PARPi). It does this by inducing DNA damage in cancer cells.

These findings offer a potential solution to PARPi resistance, a major challenge for many patients with triple-negative breast cancer (TNBC).

A Breakthrough in Targeting MYC

MYC is a crucial transcription factor that controls cell division. when MYC becomes deregulated – happening in up to 70% of human cancers – it drives uncontrolled growth, spread, and resistance to treatment. This makes MYC a prime target in oncology. However, directly inhibiting MYC has proven incredibly difficult.

Omomyc stands out as it directly binds to MYC, preventing it from driving cancer progression. The VHIO study demonstrates that Omomyc doesn’t just inhibit MYC; it also weakens cancer cells’ DNA repair mechanisms. This makes them far more vulnerable to PARPi.

Synergistic Effect with PARP Inhibitors

PARP inhibitors work by blocking a key DNA repair pathway. Cancer cells with defects in other DNA repair pathways, like those caused by MYC inhibition, are notably sensitive to PARPi. The study showed a strong synergistic effect: combining Omomyc and PARPi led to substantially greater cancer cell death than either drug alone.

“Our results indicate that Omomyc can re-sensitize PARPi-resistant TNBC cells,” explains Dr. Laura Soucek, lead author of the study and head of the VHIO’s Gene Therapy Vector Group. “This combination strategy could offer a new therapeutic option for patients who have stopped responding to PARPi.”

implications for TNBC Treatment

TNBC is an aggressive subtype of breast cancer with limited treatment options. PARPi have shown promise, but resistance develops quickly. This research suggests that Omomyc could restore PARPi sensitivity, extending the benefits of this therapy.

The researchers are now focused on further investigating the mechanisms underlying this synergy and exploring the potential for clinical trials combining Omomyc and PARPi in TNBC patients. They believe this approach could significantly improve outcomes for those facing this challenging disease.