Transferrin-conjugated liposomes loaded with carnosic acid inhibit liver cancer growth by inducing mitochondria-mediated apoptosis

• Carnosic acid-loaded liposomes (LP-CA) were prepared by ethanol injection method. • The post-insertion method was used to conjugate transferrin (Tf) to LP-CA (Tf-LP-CA). • Tf-LP-CA can target liver cancer cells to achieve the precise delivery of CA. • Tf-LP-CA suppressed tumor growth of liver cancer cell-xenotransplanted mice. • Mitochondria-related endogenous pathway was involved in Tf-LP-CA caused apoptosis. Our previous studies have proven that carnosic acid (CA) induces apoptosis of liver cancer cells. However, the poor chemical properties of CA limit its in vivo anti-cancer effects. In this study, CA was loaded into liposomes (LP-CA), and LP-CA was further conjugated with transferrin (Tf-LP-CA) to overcome the shortcomings of poor solubility and absorption at the lesion site. In HepG2 and SMMC-7721 cells, compared with CA and LP-CA, more Tf-LP-CA was absorbed by liver cancer cells, which induced higher levels of apoptosis and reduced the mitochondrial membrane potential more effectively. In HepG2- and SMMC-7721-xenotransplanted mice, Tf-LP-CA inhibited tumor growth with no cytotoxicity to the liver, spleen, or kidney. Furthermore, compared with CA and LP-CA, Tf-LP-CA targeted the tumor site more effectively, enhanced the expressions of cleaved poly(ADP-ribose) polymerase, and Caspase-3 and -9, and regulated the expression levels of B-cell lymphoma 2 (Bcl2) family members in the tumor tissues. Tf-LP-CA was taken up by tumor cells and targeted at tumor tissues, ensuring the precise delivery of CA, which further promoted mitochondria-mediated intrinsic apoptosis in the liver cancer cells. These results provide evidence for the clinical application of the Tf-LP-based CA drug delivery system for liver cancer.