Biological evaluation of pH-responsive polymer-caged nanobins for breast cancer therapy.

A series of doxorubicin-loaded polymer-caged nanobins (PCN(DXR)) were evaluated in vivo in a murine MDA-MB-231 xenograft model of triple-negative breast cancer. The cross-linked polymer cage in PCN(DXR) offers protection for the drug payload while serving as a pH-responsive trigger that enhances drug release in the acidic environments commonly seen in solid tumors and endosomes. Varying the degree of cross-linking in the polymer cage allows the surface potential of PCN(DXR), and thus the in vivo circulation lifetime of the nanocarriers, to be tuned in a facile fashion. Given these design advantages, the present study provides the first in vivo evidence that PCN(DXR) can effectively inhibit tumor growth in a murine model of breast cancer. Importantly, PCN(DXR) was well-tolerated by mice, and drug encapsulation attenuated the toxicity of free doxorubicin. Taken together, this study demonstrates the potential utility of the PCN platform in cancer therapy.