Polymer Cancerostatics Containing Cell-Penetrating Peptides: Internalization Efficacy Depends on Peptide Type and Spacer Length

Abstract

Cell-penetrating peptides (CPPs) are commonly used substances enhancing the cellular uptake of various cargoes that do not easily cross the cellular membrane. CPPs can be either covalently bound directly to the cargo or they can be attached to a transporting system such as a polymer carrier together with the cargo. In this work, several CPP–polymer conjugates based on copolymers of N-(2-hydroxypropyl)methacrylamide (pHPMA) with HIV-1 Tat peptide (TAT), a minimal sequence of penetratin (PEN), IRS-tag (RYIRS), and PTD4 peptide, and the two short hydrophobic peptides VPMLK and PFVYLI were prepared and characterized. Moreover, the biological efficacy of fluorescently labeled polymer carriers decorated with various CPPs was compared. The experiments revealed that the TAT–polymer conjugate and the PEN–polymer conjugate were internalized about 40 times and 15 times more efficiently than the control polymer, respectively. Incorporation of dodeca(ethylene glycol) spacer improved the cell penetration of both studied polymer–peptide conjugates compared to the corresponding spacer-free polymer conjugates, while the shorter tetra(ethylene glycol) spacer improved only the penetration of the TAT conjugate but it did not improve the penetration of the PEN conjugate. Finally, a significantly improved cytotoxic effect of the polymer conjugate containing anticancer drug pirarubicin and TAT attached via a dodeca(ethylene glycol) was observed when compared with the analogous polymer–pirarubicin conjugate without TAT.

Fluorescent poly[N‐(2‐hydroxypropyl) methacrylamide] nanogel by dispersion polymerization as a contrast agent for live‐cell imaging

“…The faster‐growing BJ cells can be thus a little bit more sensitive to the impact of the nanogels, however, the impact was not significantly affected the overall viability of the cells. Thus, our results confirmed the non‐cytotoxic effect of PHPMA‐based nanogel as was also previously observed with different PHPMA‐based materials, such as polymers, nanoparticles, or hydrogels 47–49 …”

“…Thus, our results confirmed the non-cytotoxic effect of PHPMA-based nanogel as was also previously observed with different PHPMA-based materials, such as polymers, nanoparticles, or hydrogels. [47][48][49] To evaluate the cell uptake of sulfo-cyanine3 azidelabeled P(HPMA-EDMA-PMA) nanogel, its intracellular distribution, and colocalization with the organelles, lysosomes, and mitochondria which can influence the future application of the newly developed nanogel as a therapeutic tool in combination with selected drugs, sulfo-cyanine3 azide-labeled P(HPMA-EDMA-PMA) nanogel was incubated with rMSC for 1 day. Then the cells were labeled with Hoechst 33342 for nuclei visualization, with Cell mask green™ FM to visualize membrane and Mito Tracker™ or Lyso Tracker™ to visualize mitochondria respectively lysosomes (Figure 11).…”

Fluorophore-Tagged Poly-Lysine RAFT Agents: Controlled Synthesis of Trackable Cell-Penetrating Peptide–Polymers

“…Interestingly, although higher increases in uptake have been reported with Penetratin and TAT-polymer conjugates, this fold increase in cellular uptake is of similar magnitudes to values reported using more complex RAFT-CPPs such as Transportan 10, which highlights the potential of this straightforward RAFT design. Importantly, the short polymer–poly-Lysine conjugates also showed good biocompatibility in MTT cytotoxicity assays (5–400 μg/mL, Figures c and S8e).…”

Novel strategies for enhanced fluorescence visualization of glioblastoma tumors based on HPMA copolymers conjugated with tumor targeting and/or cell‐penetrating peptides

“…This effect has been already observed in our previous work for CPP Tat and minipenetratin. 22 Figure 2D shows that the effect of linker length, four unit in P5-cRGD4 and a longer 12 unit in P6-cRGD, on specific binding to the α v β 3 integrin receptor is negligible at all concentrations tested. A slight improvement (about 20%) in the binding of the P6-cRGD conjugate with the longer linker over P5-cRGD4 was observed at the highest concentration of 100 µм but the difference was not statistically significant.…”