Down-regulation of cathepsin S and matrix metalloproteinase-9 via Src, a non-receptor tyrosine kinase, suppresses triple-negative breast cancer growth and metastasis

Breast cancer: Trapping tumors in place Drugs that inhibit two protein-digesting enzymes could offer potent protection against tumor growth and metastasis in an aggressive form of breast cancer. “Triple-negative breast cancer” (TNBC), which lacks three common tumor biomarkers, carries a poor prognosis for patients, with few treatment options. Enzymes that degrade the protein matrix that anchors tumor cells play a prominent role in metastasis. Researchers led by Jung Ae Kim and Byeong-Seon Jeong at Yeungnam University, Gyeongsan, South Korea, have demonstrated that these enzymes offer potential therapeutic exploitation. The researchers identified a compound that simultaneously suppresses the activity of two different matrix-digesting enzymes. This parallel inhibition markedly reduced tumor growth and metastatic invasion in mouse models of TNBC, with minimal toxicity to non-cancerous cells. This approach could thus offer new hope for treating a challenging class of tumors.