PEI-NIR Heptamethine Cyanine Nanotheranostics for Tumor Targeted Gene Delivery

Abstract

Polymer-based nanotheranostics are appealing tools for cancer treatment and diagnosis in the fast-growing field of nanomedicine. A straightforward preparation of novel engineered PEI-based nanotheranostics incorporating NIR fluorescence heptamethine cyanine dyes (NIRF-HC) to enable them with tumor targeted gene delivery capabilities is reported. Branched PEI-2 kDa (b2kPEI) is conjugated with IR-780 and IR-783 dyes by both covalent and noncovalent simple preparative methodologies varying their stoichiometry ratio. The as-prepared set of PEI-NIR-HC nanocarriers are assayed in vitro and in vivo to evaluate their gene transfection efficiency, cellular uptake, cytotoxicity, internalization and trafficking mechanisms, subcellular distribution, and tumor specific gene delivery. The results show the validity of the approach particularly for one of the covalent IR783-b2kPEI conjugates that exhibit an enhanced tumor uptake, probably mediated by organic anion transporting peptides, and favorable intracellular transport to the nucleus. The compound behaves as an efficient nanotheranostic transfection agent in NSG mice bearing melanoma G361 xenographs with concomitant imaging signal and gene concentration in the targeted tumor. By this way, advanced nanotheranostics with multifunctional capabilities (gene delivery, tumor-specific targeting, and NIR fluorescence imaging) are generated in which the NIRF-HC dye component accounts for simultaneous targeting and diagnostics, avoiding additional incorporation of additional tumor-specific targeting bioligands.

On the Mechanisms of Uptake of Tumor-Seeking Cyanine Dyes

“…When peripheral carboxylic acids are used to make amides or esters, e.g., E , then these will accumulate in tumors and persist there for a long time as albumin and similar adducts. However, conjugation of drugs to 1 -Cl via displacement of the meso -chloride is likely to give products that persist for much shorter times in tumor tissue.…”

Cyanine conjugates in cancer theranostics

“…For tumor targeted gene delivery, Eduardo et al constructed IR783-b2kPEI conjugate ( 44 ) as fluorescent nanocarrier, among which the polycationic PEI scaffold was responsible to electrostatically complex with negatively charged nucleic acids ( Fig. 11 D) [ 94 ]. It displayed propitious intracellular transport to the nucleus and was qualified as a tumor-targeted transfection agent with concurrent NIRF signal and gene expression (luciferase) in a mouse xenograft model.…”

Single chain variable fragment fused to maltose binding protein: a modular nanocarrier platform for the targeted delivery of antitumorals

“…Imaging and detection of breast cancer cells by Mal-based ligands were evaluated by confocal microscopy using a Leica TCS-SP5 II multiphoton confocal microscope following previously reported procedures 32 that prevent cross-talk of fluorophores by using distinct excitation laser lanes and non-overlapping detection channels. In all cases, cells were first seeded onto coverslips in 12well plates (density equal to 9 × 10 5 cells/well) and incubated at 37 °C (24 h) to reach a cell confluence of 80−90%.…”

“…The functionality of the MPB* tag as an attachment point was studied using the NIR dye IR783 functionalized with maltose via a vinyl sulfone-based click strategy by the reaction of IR783 piperazine 35 with vinyl sulfone maltose 25 . As a cyanine-based fluorophore, in aqueous solution (IR783)Mal tends to selfassemble into aggregates, resulting in a quenching of the fluorescence that is restored upon disassembly 36 .…”