Squalamine is a steroid-polyamine conjugate compound with broad-spectrum antimicrobial activity and anti-angiogenic activity. Squalamine selectively inhibits new blood vessel formation; this activity is thought to be mediated through inhibition of the sodium-hydrogen antiporter sodium-proton exchangers (specifically the NHE3 isoform) causing inhibition of hydrogen ion efflux from endothelial cells, with subsequent reduction of cellular proliferation. Studies in tumor-bearing mice have shown that squalamine inhibits angiogenesis and tumor growth in xenograft models of lung, breast, ovarian, and prostate cancer and in brain and breast allograft tumor models in rats. Squalamine also has been shown to prevent lung metastases in the murine Lewis lung carcinoma model, both as a single agent and in combination with various other chemotherapeutics. Squalamine does not appear to have substantial direct effects on primary tumor growth in animal models when administered as a single agent. However, enhanced antitumor responses are observed when squalamine is administered in combination with cytotoxic chemotherapeutic agents when compared with cytotoxic agents used alone. Squalamine was studied as a potential cancer drug and as a potential treatment for wet macular degeneration but as of 2018 had not succeeded in Phase III trials for any use.