Potential of Breast Cancer Drug Supinoxin in Treating Small-Cell Lung Cancer Unveiled by New Research

Scientists at Purdue University have identified the small-molecule drug Supinoxin, also known as RX5902, as a promising new therapy for small-cell lung cancer (SCLC). Despite accounting for only 15% of lung cancers, SCLC is responsible for approximately 250,000 deaths worldwide each year and has a very limited range of effective treatments. The average survival after diagnosis is approximately 10 months, highlighting the urgent need for new therapeutic options.

Elizabeth Tran, a biochemistry professor, emphasized the challenge posed by SCLC and noted that current chemotherapies are largely ineffective. Her team, including co-principal investigator Bennett Elzey, has published their findings in the journal iScience. They demonstrated that Supinoxin interacts with the DDX5 protein, which supports the malignant progression of SCLC.

The research involved examining the effects of Supinoxin on DDX5 activity in human cancer cell lines and animal models. Their approach aims to keep tumors small and prevent their growth, while combining this with other treatments to eradicate the cancer. The team suggests that such combination therapies could improve outcomes for SCLC patients.

Originally synthesized in 2010, Supinoxin has already shown effectiveness against highly aggressive triple-negative breast cancer. Its mechanism involves blocking DDX5, a protein that facilitates cancer progression by supporting mitochondrial function. Studies have shown that inhibiting DDX5 reduces oxidative phosphorylation — a critical process in energy production within cells. Cancer cells have been traditionally thought to rely solely on glycolysis for energy; however, recent evidence shows that some cancers, including SCLC, depend heavily on oxidative phosphorylation.

Tran explained that disrupting DDX5 activity hampers mitochondrial function, leading to cell death. This insight offers a new perspective on targeting cancer cell metabolism. Her research traces back to early work with yeast RNA helicases, which led her to explore their role in human cancers. She believes that focusing on RNA helicases like DDX5 could open new avenues for cancer treatment and provide novel laboratory tools for research.

Elzey and Tran are optimistic about further developing Supinoxin and exploring its potential as part of combination therapies. Their findings suggest that targeting RNA helicases and mitochondrial respiration might be a promising strategy in combating aggressive cancers like SCLC.