EGFP-Based Protein Nanoparticles with Cell-Penetrating Peptide for Efficient siRNA Delivery

Engineered Recombinant EGFP-Azurin Theranostic Nanosystem for Targeted Therapy of Prostate Cancer

Erythropoietin-producing hepatocellular (Eph) receptors and their ligands, ephrins, are the largest subfamily of receptor tyrosine kinases (RTKs) that have emerged as a new class of cancer biomarkers due to their aberrant expression in cancer progression. The activation of Eph receptors either due to their hyperexpression or via high affinity binding with their respective ephrin ligands initiates a cascade of signals that impacts cancer development and progression. In prostate cancer, the overexpression of the EphA6 receptor has been correlated with increased metastatic potential. Azurin, a small redox protein, is known to prevent tumor progression by binding to cell surface Eph receptors, inhibiting its autophosphorylation in the kinase domain and thereby disrupting Eph-ephrin signaling. Hence, a self-assembled, theranostic nanosystem of recombinant fusion protein his6EGFP-azu (80-128) was designed by conjugating enhanced green fluorescent protein (EGFP) with the C-terminal region of azurin. This design was inspired by the in silico binding study, where the analogue of ephrinA, his6EGFP-azu (80-128) showed higher binding affinity for the EphA6 receptor than the ephrinA ligands. The his6EGFP-azu (80-128) nanosystem which assembled as nanoparticles was tested for its ability to simultaneously detect and kill the prostate cancer cells, LNCaP. This was achieved by specifically targeting EphA6 receptors overexpressed on the cancer cell surface via C-terminal peptide, azu (80-128). Herein, we report antiproliferative, apoptotic, antimigratory, and anti-invasive effects of this nanosystem on LNCaP cells, while having no similar effects on EphA6 negative human normal lung cells, WI-38.

Antimicrobial peptides with anticancer activity: Today status, trends and their computational design

Some antimicrobial peptides have been shown to be able to inhibit the proliferation of cancer cell lines. Various strategies for treating cancers with active peptides have been pursued. According to the reports, anticancer peptides are important therapeutic peptides, which can act through two distinct pathways: they either just create pores in the cell membrane, or they have a vital intracellular target. In this review, publications up to Sep. 2021 had extracted form Scopus and PubMed using "antimicrobial peptide" and "anticancer peptide" as keywords. In second step, "computational design" related publications extracted. Among publications, those have similar scopes were classified and selected based on mechanisms of action and application. In this review, the most recent advances in the field of antimicrobial peptides with anti-cancer activities have been summarized. Freely available webservers such as AntiCP, ACPP, iACP, iACP-GAEnsC, ACPred are discussed here. In conclusion, despite some limitations of ACPs such as production cost and challenges, short half-life and toxicity on normal cells, the beneficial properties of AMPs make some of them good therapeutic agents for cancer therapy. Towards designing novel ACPs, the computational methods have substantial position and have been used progressively, today.

Rational engineering of a human GFP-like protein scaffold for humanized targeted nanomedicines

Green fluorescent protein (GFP) is a widely used scaffold for protein-based targeted nanomedicines because of its high biocompatibility, biological neutrality and outstanding structural stability. However, being immunogenicity a major concern in the development of drug carriers, the use of exogenous proteins such as GFP in clinics might be inadequate. Here we report a human nidogen-derived protein (HSNBT), rationally designed to mimic the structural and functional properties of GFP as a scaffold for nanomedicine. For that, a GFP-like β-barrel, containing the G2 domain of the human nidogen, has been rationally engineered to obtain a biologically neutral protein that self-assembles as 10nm-nanoparticles. This scaffold is the basis of a humanized nanoconjugate, where GFP, from the well-characterized protein T22-GFP-H6, has been substituted by the nidogen-derived GFP-like HSNBT protein. The resulting construct T22-HSNBT-H6, is a humanized CXCR4-targeted nanoparticle that selectively delivers conjugated genotoxic Floxuridine into cancer CXCR4+ cells. Indeed, the administration of T22-HSNBT-H6-FdU in a CXCR4-overexpressing colorectal cancer mouse model results in an even more efficient selective antitumoral effect than that shown by its GFP-counterpart, in absence of systemic toxicity. Therefore, the newly developed GFP-like protein scaffold appears as an ideal candidate for the development of humanized protein nanomaterials and successfully supports the tumor-targeted nanoscale drug T22-HSNBT-H6-FdU. STATEMENT OF SIGNIFICANCE: Targeted nanomedicine seeks for humanized and biologically neutral protein carriers as alternative of widely used but immunogenic exogenous protein scaffolds such as green fluorescent protein (GFP). This work reports for the first time the rational engineering of a human homolog of the GFP based in the human nidogen (named HSNBT) that shows full potential to be used in humanized protein-based targeted nanomedicines. This has been demonstrated in T22-HSNBT-H6-FdU, a humanized CXCR4-targeted protein nanoconjugate able to selectively deliver its genotoxic load into cancer cells.

gH625 Cell-Penetrating Peptide Promotes the Endosomal Escape of Nanovectorized siRNA in a Triple-Negative Breast Cancer Cell Line

The use of small interfering RNA (siRNA) to regulate oncogenes appears as a promising strategy in the context of cancer therapy, especially if they are vectorized by a smart delivery system. In this study, we investigated the cellular trafficking of a siRNA nanovector (called CS-MSN) functionalized with the cell-penetrating peptide gH625 in a triple-negative breast cancer model. With complementary techniques, we showed that siRNA nanovectors were internalized by both clathrin- and caveolae-mediated endocytosis. The presence of gH625 at the surface of the siRNA nanovector did not modify the entry pathway of CS-MSN, but it increased the amount of siRNA found inside the cells. Results suggested an escape of siRNA from endosomes, which is enhanced by the presence of the peptide gH625, whereas nanoparticles continued their trafficking into lysosomes. The efficiency of CS-MSN to inhibit the GFP in MDA-MB-231 cells was 1.7-fold higher than that of the nanovectors without gH625.

Efficient siRNA delivery and gene silencing using a lipopolypeptide hybrid vector mediated by a caveolae-mediated and temperature-dependent endocytic pathway

Background

We developed a non-viral vector, a combination of HIV-1 Tat peptide modified with histidine and cysteine (mTat) and polyethylenimine, jetPEI (PEI), displaying the high efficiency of plasmid DNA transfection with little toxicity. Since the highest efficiency of INTERFERin (INT), a cationic amphiphilic lipid-based reagent, for small interfering RNA (siRNA) transfection among six commercial reagents was shown, we hypothesized that combining mTat/PEI with INT would improve transfection efficiency of siRNA delivery. To elucidate the efficacy of the hybrid vector for siRNA silencing, β-actin expression was measured after siRNA β-actin was transfected with mTat/PEI/INT or other vectors in HSC-3 human oral squamous carcinoma cells.

Results

mTat/PEI/INT/siRNA produced significant improvement in transfection efficiency with little cytotoxicity compared to other vectors and achieved ≈ 100% knockdown of β-actin expression compared to non-treated cells. The electric charge of mTat/PEI/INT/siRNA was significantly higher than INT/siRNA. The particle size of mTat/PEI/INT/siRNA was significantly smaller than INT/siRNA. Filipin III and β-cyclodextrin, an inhibitor of caveolae-mediated endocytosis, significantly inhibited mTat/PEI/INT/siRNA transfection, while chlorpromazine, an inhibitor of clathrin-mediated endocytosis, did not inhibit mTat/PEI/INT/siRNA transfection. Furthermore, the transfection efficiency of mTat/PEI/INT at 4 °C was significantly lower than 37 °C.

Conclusions

These findings demonstrated the feasibility of using mTat/PEI/INT as a potentially attractive non-viral vector for siRNA delivery.

A tumor-targeting protein nanoparticle based on Tat peptide and enhanced green fluorescent protein

A protein-based nanoparticle containing cell penetrating peptides (CPPs) and enhanced green fluorescent protein (EGFP) was developed through a genetic engineering method.