Researchers at the University of Michigan have discovered that a novel molecular glue, RPT04402, can potentially inhibit cancer growth in patients with non-small cell lung cancer and high-grade uterine cancer. These findings were detailed in recent studies assessing the effects of RPT04402 on the protein phosphatase 2A (PP2A), which plays a key role in tumor suppression.
PP2A is a protein complex composed of three proteins that, when correctly assembled, helps control many cell signaling pathways crucial for normal cellular function. Disruption in PP2A assembly is frequently observed in various cancers, including lung and uterine cancer.
Progress in Lung Cancer Treatment
Lung cancer remains the second-most common cancer in the United States and is the leading cause of cancer-related deaths. Non-small cell lung cancer, which accounts for over 80% of lung cancer cases, is characterized by larger, slower-growing tumor cells. The KRAS gene, often mutated in approximately 30% of these cases, significantly impacts patient survival and treatment resistance.
In a study published in The Journal of Clinical Investigation, the research team found that utilizing RPT04402 alongside current anti-cancer drugs, such as adagrasib and trametinib, can enhance treatment effectiveness. These drugs were shown to destabilize PP2A, which may contribute to treatment resistance. However, when RPT04402 was introduced, it stabilized the PP2A complex and resulted in cancer cell death.
Animal model testing confirmed that tumors shrank under this treatment, with the combination therapy postponing resistance and extending treatment efficacy to more than 150 days in mice. Goutham Narla, a professor at the Rogel Cancer Center, expressed hope about the potential of this approach, stating it might benefit 20-30% of all non-small cell lung cancer cases. Clinical trials are expected to start soon in collaboration with Spring Works Therapeutics and Merck.
Advancements in Uterine Cancer Research
Uterine cancer has become the most common cancer of the female reproductive system, with rising incidence and mortality rates, particularly among aggressive high-grade types. Most patients do not respond well to existing treatments, and recurrent PP2A mutations have been linked to the aggressiveness of this cancer.
A separate study, detailed in Science Translational Medicine, demonstrated that RPT04402 could restore PP2A function, aiding in the suppression of uterine cancer cell growth. Both mouse models and patient-derived tumor samples indicated reduced tumor size without notable side effects or toxicity, positioning RPT04402 as a groundbreaking treatment option for high-grade uterine cancers. Caitlin O’Connor, a Research Assistant Professor, noted this could be the first targeted therapy aimed at addressing the underlying cause of high-grade uterine cancers.
The research team is also considering expanding their investigations to include additional cancers driven by PP2A mutations, indicating a broad potential for future applications.
