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Chemists isolated xylarimides A and B, two 21-membered cyclic depsipeptides with a previously undescribed chemical unit, from the fungus Xylaria striata. Xylarimide A slowed the growth of kidney cancer cell lines and 786-O tumors in mice. It binds the autophagy protein ATG7 and suppresses AKT-mTOR signaling, driving cancer cells into lethal autophagy.
Researchers at Beijing University of Technology and the radiopharmaceutical company HTA reported in the Journal of Medicinal Chemistry on October 17, 2026 two gallium-68 cyclic peptide probes, WF1 and WF2, built to image carbonic anhydrase IX (CAIX), a marker of clear cell kidney cancer. Changing the peptide's ring-closing linker kept nanomolar binding to CAIX while sharply reducing binding to the related enzyme CAII, which made the earlier probe 68Ga-DPI-4452 accumulate in the digestive tract. In mice with kidney tumors, tumor uptake matched the older probe with less gut signal, and the probes bound human kidney cancer tissue samples; they have not been tested in patients.