Assessing the In Vivo Targeting Efficiency of Multifunctional Nanoconstructs Bearing Antibody-Derived Ligands

Abstract

A great challenge in nanodiagnostics is the identification of new strategies aimed to optimize the detection of primary breast cancer and metastases by the employment of target-specific nanodevices. At present, controversial proof has been provided on the actual importance of surface functionalization of nanoparticles to improve their in vivo localization at the tumor. In the present paper, we have designed and developed a set of multifunctional nanoprobes, modified with three different variants of a model antibody, that is, the humanized monocolonal antibody trastuzumab (TZ), able to selectively target the HER2 receptor in breast cancer cells. Assuming that nanoparticle accumulation in target cells is strictly related to their physicochemical properties, we performed a comparative study of internalization, trafficking, and metabolism in MCF7 cells of multifunctional nanoparticles (MNP) functionalized with TZ or with alternative lower molecular weight variants of the monoclonal antibody, such as the half-chain (HC) and scFv fragments (scFv). Hence, to estimate to what extent the structure of the surface bioligand affects the targeting efficiency of the nanoconjugate, three cognate nanoconstructs were designed, in which only the antibody form was differentiated while the nanoparticle core was maintained unvaried, consisting of an iron oxide spherical nanocrystal coated with an amphiphilic polymer shell. In vitro, in vivo, and ex vivo analyses of the targeting efficiency and of the intracellular fate of MNP-TZ, MNP-HC, and MNP-scFv suggested that the highly stable MNP-HC is the best candidate for application in breast cancer detection. Our results provided evidence that, in this case, active targeting plays an important role in determining the biological activity of the nanoconstruct.

Development of^99mTc-radiolabeled nanosilica for targeted detection of HER2-positive breast cancer

“…19 Therefore, a heterobifunctional PEG containing a maleimido group was covalently linked to the amine residues of the SiNPs (Scheme 1, step 2). After the reduction of disulfide bonds bridging the two chains of the antibody, the resulting thiol groups of the Hc-TZ were reacted with the maleimides, leading to the immobilization of the antibody on the shell surface (Scheme 1, step 3).…”

“…17 Recently, various ligands that can specifically bind to receptors overexpressed in cancer cells, including peptides and antibodies, have been coengineered with smart nanomaterials for the design and construction of novel drug delivery systems and targeted diagnostic probes. 18,19 Silica NPs (SiNPs) possess high biocompatibility and their functionalization with monoclonal antibodies (eg, TZ for HER2 + BC) can be a useful tool for both tumor imaging and targeted chemotherapy. 20 In addition, these NPs are intrinsically hydrophilic, easy and inexpensive to prepare and can be chemically modified in a straightforward manner.…”

Bridging the Knowledge of Different Worlds to Understand the Big Picture of Cancer Nanomedicines

“…[46] For example, compared to non-targeted magnetic nanoparticles, targeted ones with anti-HER2 monoclonal antibody specific for breast cancer cells have demonstrated 10-30-fold increased concentrations in tumor tissues. [47] Similarly, nanoparticles have also been conjugated with RGD (Arg-Gly-Asp) peptides due to their high affinity to αvβ3 integrin receptors that are highly expressed in tumor cells, thus enhancing the intratumoral drug delivery. [48] Aptamers are small oligonucleotides that can be selected to bind tightly and specifically to a target molecule, are also widely applied into nanoparticle formation besides the surface modification.…”

CD44-engineered mesoporous silica nanoparticles for overcoming multidrug resistance in breast cancer

“…Although the great approach of selectively delivering drugs to targeted cancer cells by specifically binding to the antigens overexpressed on the cancer cells surface. The antibody-based therapeutics can provide high affinity to cancer cell receptors, facilitate "enhance permeation and retention" (EPR) effect, achieve higher nanoparticle accumulation at the tumor site, significantly enhance delivery efficacy and minimize toxicity [19].…”