BIRC5 and cancer: Furthermore, the Western blot assay revealed that compounds 1–3 suppressed the expression of anti-apoptotic proteins XIAP and survivin, but increased the relative levels of caspase-3/cleaved caspase-3 in A549 cells, suggesting that the reduced XIAP and survivin expression in compounds 1–3 treated cancer cells may lead to apoptosis via a caspase-3/cleaved-caspase-3 dependent mechanism.