Heparan sulfate targeting strategy for enhancing liposomal drug accumulation and facilitating deep distribution in tumors.

Nanoparticles (NPs), such as liposomes, effectively evade the severe toxicity of unexpected accumulation and passively shuttle drugs into tumor tissues by enhanced permeability and retention. In the case of non-small cell lung cancer and pancreatic ductal adenocarcinoma, cancer-associated fibroblasts promote the aggregation of a gel-like extracellular matrix that forms a physical barrier in the desmoplastic stroma of the tumor. These stroma are composed of protein networks and glycosaminoglycans (GAGs) that greatly compromise tumor-penetrating performance, leading to insufficient extravasation and tissue penetration of NPs. Moreover, the presence of heparan sulfate (HS) and related proteoglycans on the cell surface and tumor extracellular matrix may serve as molecular targets for NP-mediated drug delivery. Here, a GAG-binding peptide (GBP) with high affinity for HS and high cell-penetrating activity was used to develop an HS-targeting delivery system. Specifically, liposomal doxorubicin (L-DOX) was modified by post-insertion with the GBP. We show that the in vitro uptake of L-DOX in A549 lung adenocarcinoma cells increased by GBP modification. Cellular uptake of GBP-modified L-DOX (L-DOX-GBP) was diminished in the presence of extracellular HS but not in the presence of other GAGs, indicating that the interaction with HS is critical for the cell surface binding of L-DOX-GBP. The cytotoxicity of doxorubicin positively correlated with the molecular composition of GBP. Moreover, GBP modification improved the in vivo distribution and anticancer efficiency of L-DOX, with enhanced desmoplastic targeting and extensive distribution. Taken together, GBP modification may greatly improve the tissue distribution and delivery efficiency of NPs against HS-abundant desmoplastic stroma-associated neoplasm.

Cell Penetrating Peptide as a High Safety Anti-Inflammation Ingredient for Cosmetic Applications.

Cosmeceutical peptides have become an important topic in recent decades in both academic and industrial fields. Many natural or synthetic peptides with different biological functions including anti-ageing, anti-oxidation, anti-infection and anti-pigmentation have been developed and commercialized. Current cosmeceutical peptides have already satisfied most market demand, remaining: "cargos carrying skin penetrating peptide with high safety" still an un-met need. To this aim, a cell-penetrating peptide, CPPAIF, which efficiently transported cargos into epithelial cells was exanimated. CPPAIF was evaluated with cell model and 3D skin model following OECD guidelines without using animal models. As a highly stable peptide, CPPAIF neither irritated nor sensitized skin, also did not disrupt skin barrier. In addition, such high safety peptide had anti-inflammation activity without allergic effect. Moreover, cargo carrying activity of CPPAIF was assayed using HaCaT cell model and rapid CPPAIF penetration was observed within 30 min. Finally, CPPAIF possessed transepidermal activity in water in oil formulation without disruption of skin barrier. All evidences indicated that CPPAIF was an ideal choice for skin penetrating and its anti-inflammatory activity could improve skin condition, which made CPPAIF suitable and attractive for novel cosmeceutical product development.

MMP-13 is involved in oral cancer cell metastasis.

The oral cancer cell line OC3-I5 with a highly invasive ability was selected and derived from an established OSCC line OC3. In this study, we demonstrated that matrix metalloproteinases protein MMP-13 was up-regulated in OC3-I5 than in OC3 cells. We also observed that expression of epithelial-mesenchymal transition (EMT) markers including Twist, p-Src, Snail1, SIP1, JAM-A, and vinculin were increased in OC3-I5 compared to OC3 cells, whereas E-cadherin expression was decreased in the OC3-I5 cells. Using siMMP-13 knockdown techniques, we showed that siMMP-13 not only reduced the invasion and migration, but also the adhesion abilities of oral cancer cells. In support of the role of MMP-13 in metastasis, we used MMP-13 expressing plasmid-transfected 293T cells to enhance MMP-13 expression in the OC3 cells, transplanting the MMP-13 over expressing OC3 cells into nude mice led to enhanced lung metastasis. In summary, our findings show that MMP-13 promotes invasion and metastasis in oral cancer cells, suggesting altered expression of MMP-13 may be utilized to impede the process of metastasis.

A Heparan Sulfate-Binding Cell Penetrating Peptide for Tumor Targeting and Migration Inhibition.

As heparan sulfate proteoglycans (HSPGs) are known as co-receptors to interact with numerous growth factors and then modulate downstream biological activities, overexpression of HS/HSPG on cell surface acts as an increasingly reliable prognostic factor in tumor progression. Cell penetrating peptides (CPPs) are short-chain peptides developed as functionalized vectors for delivery approaches of impermeable agents. On cell surface negatively charged HS provides the initial attachment of basic CPPs by electrostatic interaction, leading to multiple cellular effects. Here a functional peptide (CPPecp) has been identified from critical HS binding region in hRNase3, a unique RNase family member with in vitro antitumor activity. In this study we analyze a set of HS-binding CPPs derived from natural proteins including CPPecp. In addition to cellular binding and internalization, CPPecp demonstrated multiple functions including strong binding activity to tumor cell surface with higher HS expression, significant inhibitory effects on cancer cell migration, and suppression of angiogenesis in vitro and in vivo. Moreover, different from conventional highly basic CPPs, CPPecp facilitated magnetic nanoparticle to selectively target tumor site in vivo. Therefore, CPPecp could engage its capacity to be developed as biomaterials for diagnostic imaging agent, therapeutic supplement, or functionalized vector for drug delivery.

A biologically inspired lung-on-a-chip device for the study of protein-induced lung inflammation.

This study reports a biomimetic microsystem that reconstitutes the lung microenvironment for monitoring the role of eosinophil cationic protein (ECP) in lung inflammation. ECP induces the airway epithelial cell expression of CXCL-12, which in turn stimulates the migration of fibrocytes towards the epithelium. This two-layered microfluidic system provides a feasible platform for perfusion culture, and was used in this study to reveal that the CXCL12-CXCR4 axis mediates ECP induced fibrocyte extravasation in lung inflammation. This 'lung-on-a-chip' microdevice serves as a dynamic transwell system by introducing a flow that can reconstitute the blood vessel-tissue interface for in vitro assays, enhancing pre-clinical studies. We made an attempt to develop a new microfluidic model which could not only simulate the transwell for studying cell migration, but could also study the migration in the presence of a flow mimicking the physiological conditions in the body. As blood vessels are the integral part of our body, this model gives an opportunity to study more realistic in vitro models of organs where the blood vessel i.e. flow based migration is involved.

Functional characterization of ECP-heparin interaction: a novel molecular model.

Human eosinophil cationic protein (ECP) and eosinophil derived neurotoxin (EDN) are two ribonuclease A (RNaseA) family members secreted by activated eosinophils. They share conserved catalytic triad and similar three dimensional structures. ECP and EDN are heparin binding proteins with diverse biological functions. We predicted a novel molecular model for ECP binding of heparin hexasaccharide (Hep6), [GlcNS(6S)-IdoA(2S)]3, and residues Gln(40), His(64) and Arg(105) were indicated as major contributions for the interaction. Interestingly, Gln(40) and His(64) on ECP formed a clamp-like structure to stabilize Hep6 in our model, which was not observed in the corresponding residues on EDN. To validate our prediction, mutant ECPs including ECP Q40A, H64A, R105A, and double mutant ECP Q40A/H64A were generated, and their binding affinity for heparins were measured by isothermal titration calorimetry (ITC). Weaker binding of ECP Q40A/H64A of all heparin variants suggested that Gln(40)-His(64) clamp contributed to ECP-heparin interaction significantly. Our in silico and in vitro data together demonstrate that ECP uses not only major heparin binding region but also use other surrounding residues to interact with heparin. Such correlation in sequence, structure, and function is a unique feature of only higher primate ECP, but not EDN.

Basic amino acid residues of human eosinophil derived neurotoxin essential for glycosaminoglycan binding.

Human eosinophil derived neurotoxin (EDN), a granule protein secreted by activated eosinophils, is a biomarker for asthma in children. EDN belongs to the human RNase A superfamily possessing both ribonucleolytic and antiviral activities. EDN interacts with heparin oligosaccharides and heparin sulfate proteoglycans on bronchial epithelial Beas-2B cells. In this study, we demonstrate that the binding of EDN to cells requires cell surface glycosaminoglycans (GAGs), and the binding strength between EDN and GAGs depends on the sulfation levels of GAGs. Furthermore, in silico computer modeling and in vitro binding assays suggest critical roles for the following basic amino acids located within heparin binding regions (HBRs) of EDN 34QRRCKN39 (HBR1), 65NKTRKN70 (HBR2), and 113NRDQRRD119 (HBR3) and in particular Arg35, Arg36, and Arg38 within HBR1, and Arg114 and Arg117 within HBR3. Our data suggest that sulfated GAGs play a major role in EDN binding, which in turn may be related to the cellular effects of EDN.

In silico prediction and in vitro characterization of multifunctional human RNase3.

Human ribonucleases A (hRNaseA) superfamily consists of thirteen members with high-structure similarities but exhibits divergent physiological functions other than RNase activity. Evolution of hRNaseA superfamily has gained novel functions which may be preserved in a unique region or domain to account for additional molecular interactions. hRNase3 has multiple functions including ribonucleolytic, heparan sulfate (HS) binding, cellular binding, endocytic, lipid destabilization, cytotoxic, and antimicrobial activities. In this study, three putative multifunctional regions, (34)RWRCK(38) (HBR1), (75)RSRFR(79) (HBR2), and (101)RPGRR(105) (HBR3), of hRNase3 have been identified employing in silico sequence analysis and validated employing in vitro activity assays. A heparin binding peptide containing HBR1 is characterized to act as a key element associated with HS binding, cellular binding, and lipid binding activities. In this study, we provide novel insights to identify functional regions of hRNase3 that may have implications for all hRNaseA superfamily members.