ACTA1 and cancer: As shown, ZL170-treated tumors exhibited reduced ECM deposition and impaired infiltration of CD31+ endothelial cells, α-SMA+ cancer-associated fibroblasts as well as F4/80+ macrophages (Fig. 7m and n), suggesting that ZL170 treatment created a suppressive tumor microenvironment, which in turn suppressed tumor growth, invasion and metastasis in TNBC.