Cancer-targeted and intracellular delivery of Bcl-2-converting peptide with functional macroporous silica nanoparticles for biosafe treatment.

Therapeutic peptide, NuBCP-9 (N9) as a Bcl-2 functional converter, has been demonstrated to have the remarkable anticancer efficiency in Bcl-2-abundant cancer. However, it faced technical challenges in clinical use, such as the low bioavailability, the easily-destroyed bio-stability, and the insusceptibility to cellular interior. With the potential of mesoporous silica nanoparticles (MSNs) as the promising delivery vehicle of therapeutic macromolecules, we developed a kind of MSNs with the surface coating of folic acid (FA) for cancer cell targeting and with the macropore loading of N9 peptide for cancer therapy. Our results showed that the functional MSNs had the relatively greater biosafety than the naked MSNs in zebrafish models, leading to less than 30% embryo of death at 200 µg/ml, which could further specifically target the folate receptor (FR)-overexpressed cervical cancer HeLa cells instead of FR-negative normal embryonic kidney HEK 293T cells in a FA-competitive manner. N9 peptide with the delivery of functional MSNs could be internalized by HeLa cells, and co-localized with mitochondria in a Bcl-2-dependent manner. Moreover, N9 peptide delivered by FA-modified MSNs displayed the excellent anticancer efficiency with great selectivity, inducing approximately 52% HeLa cells into apoptosis. In summary, our results illustrated the potential of functional MSNs with large pore size as an efficient nanocarrier for the intracellular delivery of peptide drugs with targeting proteins to realize cancer therapy.