Validation of Dual-Action Chemo-Radio-Labeled Nanocarriers with High Efficacy against Triple-Negative Breast Cancer.

Identification and selectivity of molecular targets with prolonged action for difficult-to-target cancer such as triple-negative breast cancer (TNBC) represent a persisting challenge in the precision delivery of therapeutics. In the quest to target undruggable sites, this study validates the bioavailability of polydopamine-sealed mesoporous silica nanocarriers (PDA-mSiO2) for in vivo drug delivery to TNBC. For controlled transport and release, the chemotherapeutic drug doxorubicin was encapsulated in mSiO2 nanocarriers coated with a PDA layer serving as a stimuli-responsive gatekeeper or seal. For unifying targeting and treatment modalities, these nanocarriers were covalently conjugated to a macrocyclic chelator (DOTA) and folate (FA-mSiO2.) that enabled incorporation of radionuclides and identification of FR Alpha (FolRα) receptors present on TNBC cells. The robust chemical design of FA- and DOTA-functionalized PDA-coated mSiO2 nanocarriers constitutes mild reaction conditions to avoid the loss of surface-bound molecules. The radiolabeling studies with the theranostic pair 68Ga and 177Lu showed quantitative trends for radiochemical efficacy and purity. Nanocarriers equipped with both radiolabels and affinity ligands were optimally stable when incubated with human serum for up to 120 h (177Lu), demonstrating hydrophilicity with a partition coefficient (log P) of -3.29 ± 0.08. Specifically, when incubated with TNBC cells, the cells received significant FA-mSiO2 carriers, demonstrating efficient carrier internalization and time-dependent uptake. Moreover, in vivo results visualize the retention of drug-filled carriers at the tumor sites for a long time, which holds promise for therapeutic studies. This research work demonstrates for the first time the successful dual conjugation of nanocarriers through the colocation of radionuclides and anticancer drugs that is promising for both live molecular imaging and enhanced therapeutic effect for TNBC.

Receptor-Mediated In Vivo Targeting of Breast Cancer Cells with 17α-Ethynylestradiol-Conjugated Silica-Coated Gold Nanoparticles.

Efficient therapies for breast cancer remain elusive because of the lack of strategies for targeted transport and receptor-mediated uptake of synthetic drug molecules by cancer cells. Conjugation of nanoparticles (NPs) with active targeting ligands enabling selective molecular recognition of antigens expressed on the surface of cancer cells is promising for localization and treatment of malignant cells. In this study, covalent attachment of synthetic estrogen 17α-ethynylestradiol on the silica (SiO2) shell of silica-gold NPs (SiO2@Au) was undertaken to improve the cancer-targeting ability of the nano-biotags. Chemical and structural analysis of the bioconjugates examined in solution (UV-vis and ξ-potential) and solid state (Fourier transform infrared spectroscopy, X-ray diffractometry, and transmission electron microscopy) confirmed the identity of the carrier particles and surface-bound ligands. The mesoporous silica shell served as a reservoir for anticancer drugs (doxorubicin and quercetin) and to facilitate covalent attachment of receptor molecules by click chemistry protocols. The chemoselective recognition between the nanoconjugates and cell membranes was successfully demonstrated by the accumulation of nanoprobes in the tumor tissue of mice with subcutaneous breast cancer, whereas healthy cells were unaffected. The drug release studies showed sustained release kinetics over several weeks. These findings elaborate the exceptional selectivity and potential of estrogen-coated nano-biolabels in efficient diagnosis and detection of breast cancer cells.