Multimeric Amphipathic α‐Helical Sequences for Rapid and Efficient Intracellular Protein Transport at Nanomolar Concentrations

Abstract

An amphipathic leucine (L) and lysine (K)‐rich α‐helical peptide is multimerized based on helix‐loop‐helix structures to maximize the penetrating activities. The multimeric LK‐based cell penetrating peptides (LK‐CPPs) can penetrate cells as protein‐fused forms at 100–1000‐fold lower concentrations than Tat peptide. The enhanced penetrating activity is increased through multimerization by degrees up to the tetramer level. The multimeric LK‐CPPs show rapid cell penetration through macropinocytosis at low nanomolar concentrations, unlike the monomeric LK, which have slower penetrating kinetics at much higher concentrations. The heparan sulfate proteoglycan (HSPG) receptors are highly involved in the rapid internalization of multimeric LK‐CPPs. As a proof of concept of biomedical applications, an adipogenic transcription factor, peroxisome proliferator‐activated receptor gamma 2 (PPAR‐γ 2), is delivered into preadipocytes, and highly enhanced expression of adipogenic genes at nanomolar concentrations is induced. The multimeric CPPs can be a useful platform for the intracellular delivery of bio‐macromolecular reagents that have difficulty with penetration in order to control biological reactions in cells at feasible concentrations for biomedical purposes.

Highly Efficient Photothermal Therapy with Cell-Penetrating Peptide-Modified Bumpy Au Triangular Nanoprisms using Low Laser Power and Low Probe Dose

“…The rapid and efficient cellular upake of the LK-BATrism could facilitate the generation of a larger temperature increase upon laser irradiation compared to bare probes at such lower concentrations. Furthermore, we compared the activity of the LK peptide with a well-known CPP, the TAT sequence, ,,− on the enhancement of cellular uptake of the nanoprobes (Figure S12). The LK-BATrism showed significantly higher cell internalization than the TAT-BATrisms, supporting the superior activity of LK-based cell penetration.…”

“…In a previous study, LK peptides showed a higher cellular uptake efficiency than other commonly used CPPs. 26,27 Therefore, conjugation of LK peptides on the BATrisms will allow the use of a low probe dose and low laser power with proper modification of these peptides to the particles by efficiently increasing cellular accumulation. The amino acid sequence and characterization of the peptides used in this study are listed in Table S2 and Figure S7, respectively.…”

“…Nanoparticles of anisotropic morphology with a rough surface can enhance the electromagnetic field (EMF) and red-shift the absorption peak, , enabling efficient PTT conversion and deep tissue penetration . Moreover, the PTT probes need to efficiently enter cells in order to maximize their therapeutic effectiveness. , In previous research, it was found that the multimeric form of an α-helical amphipathic peptide rich in leucine (L) and lysine (K) sequences (LK peptide) induced rapid and efficient endocytosis through heparan sulfate proteoglycan receptors (HSPGs) even at much lower concentrations than conventional cell-penetrating peptides (CPPs). − Therefore, to improve the cellular uptake of the probes for a more efficient PTT, an LK peptide-based CPP was employed for surface functionalization. Coupled with a large surface area and diverse peptide modification angles, offered by the bumpy surfaces of BATrisms, the LK peptide modification is expected to maximize the photothermal therapeutic effect against triple-negative breast cancer (TNBC) cells by enhancing the cellular uptake efficiency.…”

Research Progress of Conjugated Nanomedicine for Cancer Treatment

“…Furthermore, cationic CPPs present problems, such as their inability to selectively home to the target. To improve the performance of CPPs-based PDCs, recently, a study found that multimers of lysine (K) and leucine (L) of the amphiphilic α-helical LK sequence can penetrate cells at the nanomolar level, which was 100–1000 folds lower than the transverse concentration of traditional CPPs [ 86 ]. The stronger the interaction between CPPs and cell surface receptors, the faster the PDCs enter the tumor cells [ 87 , 88 ].…”

Combination of peptides with biological, organic, and inorganic materials for synergistically enhanced diagnostics and therapeutics

“…[107] The anisotropic morphology and rough surface of BATrisms allowed the PICs to exhibit a promising PTT conversion efficiency (~86%) by enhancing the electromagnetic field. Efficient delivery of PICs into tumor cells was achieved by the conjugation of a cell-penetrating peptide, [108,109] the leucine-and lysine-rich peptide (LK peptide, LKKLLKLLKKLLKLGGLKKLLKLLKKLLKLAG), to the surface of BATrisms. Based on these merits, the PICs demonstrated antitumor efficacy with a very small dose (2.5 μg Au) under very low laser intensity (808 nm, 0.25 W/cm 2 ).…”