To improve antitumor efficiency of
chemotherapy and reduce side effect, according to the physiological characteristics of
tumor tissues and
tumor intracellular microenvironment, a multifunctional drug delivery system with properties of long circulation, active targeting, redox and pH triggered drug release was established based on the
Generation 4 polyamidoamine dendrimer (PAMAM). First, the redox cleavable
disulfide bonds (SS) were introduced for linking
polyethylene glycol (PEG) with PAMAM to form PAMAM-S-S-PEG (PSSP). Then
cRGD peptide was applied to the PEG end of PSSP to construct RGD-PSSP conjugates. Finally, encapsulating the antitumor
chemotherapy drug doxorubicin (DOX) into the hydrophobic cavity of RGD-PSSP conjugates constructed the RGD-PSSP/DOX drug delivery system. The in vitro experiments displayed that RGD-PSSP/DOX NPs showed obviously redox and pH dual sensitive drug release profile. MTT and cell uptake observation elucidated cRGD modification could increase the cytotoxicity, and promote the uptake of B16 cells and HUVEC cells both overexpressing
integrin ανβ3on cell membrane. Cell uptake mechanism investigation further revealed that RGD-PSSP/DOX interacted with plasma membrane via specific recognition of
cRGD peptide with
integrin ανβ3, and was subsequently internalized mainly through
clathrin- and
caveolin-mediated endocytosis. Remarkably, RGD-PSSP/DOX presented superior anticancer activity and lower heart and kidney toxicity in vivo, which could be regarded as a potential candidate for efficient antitumor
chemotherapy drug delivery.