Pyrroloquinoline Quinone (PQQ) Potentiates Chemo- and Radiosensitization of Cancer Cells in Synergistic way

Pyrroloquinoline quinone (PQQ), a naturally occurring redox cofactor, has demonstrated a wide range of biological activities, particularly its ability to modulate mitochondrial function and reactive oxygen species (ROS). This study aimed to evaluate the potential of PQQ to enhance the efficacy of chemotherapeutic drugs and radiation in cancer cell lines (A549, MCF-7, and HT-29). Results revealed that PQQ significantly reduced cell viability in a dose-and time-dependent manner, particularly in combination with chemotherapeutic drugs (5-FU, Tamoxifen, Carboplatin, and Doxorubicin) and gamma radiation. Furthermore, PQQ in combination of chemotherapeutic drugs (5-FU) and gamma radiation resulted in increased ROS generation, mitochondrial dysfunction, GSH depletion, and DNA damage, all contributing to enhanced cancer cell death. These findings suggest for first time that PQQ acts as a potent chemo-and radiosensitizer, with the potential to improve cancer treatment outcomes while reducing the required doses of chemotherapy and radiation, thereby possible minimizing side effects.