Biodegradable Polyurethane Scaffolds in Regeneration Therapy: Characterization and In Vivo Real-Time Degradation Monitoring by Grafted Fluorescent Tracer.

There is an urgent need to assess material degradation in situ and in real time for their promising application in regeneration therapy. However, traditional monitoring methods in vitro cannot always profile the complicated behavior in vivo. This study designed and synthesized a new biodegradable polyurethane (PU-P) scaffold with polycaprolactone glycol, isophorone diisocyanate, and l-lysine ethyl ester dihydrochloride. To monitor the degradation process of PU-P, calcein was introduced into the backbone (PU-5) as a chromophore tracing in different sites of the body and undegradable fluorescent scaffold (CPU-5) as the control group. Both PU-P and PU-5 can be enzymatically degraded, and the degradation products are molecularly small and biosafe. Meanwhile, by virtue of calcein anchoring with urethane, polymer chains of PU-5 have maintained the conformational stability and extended the system conjugation, raising a structure-induced emission effect that successfully achieved a significant enhancement in the fluorescence intensity better than pristine calcein. Evidently, unlike the weak fluorescent response of CPU-5, PU-5 and its degradation can be clearly imaged and monitored in real time after implantation in the subcutaneous tissue of nude mice. Meanwhile, the in situ osteogeneration has also been promoted after the two degradable scaffolds have been implanted in the rabbit femoral condyles and degraded with time. To sum up, the strategy of underpinning tracers into degradable polymer chains provides a possible and effective way for real-time monitoring of the degradation process of implants in vivo.

Synergetic Effect of Electrical and Topographical Cues in Aniline Trimer-Based Polyurethane Fibrous Scaffolds on Tissue Regeneration.

Processibility and biodegradability of conductive polymers are major concerns when they are applied to tissue regeneration. This study synthesizes dissolvable and conductive aniline trimer-based polyurethane copolymers (DCPU) and processes them into scaffolds by using electrospinning with different patterns (random, oriented, and latticed). The effects of topographic cue changes on electrical signal transmission and further regulation of cell behaviors concerning bone tissue are researched. Results show that DCPU fibrous scaffolds possessed good hydrophilicity, swelling capacity, elasticity, and fast biodegradability in enzymatic liquid. In addition, the conductivity and efficiency of electrical signal transmission can be tuned by changing the surface's topological structure. Among them, oriented DCPU scaffolds (DCPU-O) showed the best conductivity with the lowest ionic resistance value. Furthermore, the viability and proliferation results of bone mesenchymal stem cells (BMSCs) demonstrate a significant increase on three DCPU scaffolds compared to AT-free scaffolds (DPU-R). Especially, DCPU-O scaffolds exhibit superior abilities to promote cell proliferation because of their unique surface topography and excellent electroactivity. Concurrently, the DCPU-O scaffolds can synergistically promote osteogenic differentiation in terms of osteogenic differentiation and gene expression levels when combined with electrical stimulation. Together, these results suggest a promising use of DCPU-O fibrous scaffolds in the application of tissue regeneration.

Enhanced biomineralization of shape memory composite scaffolds from citrate functionalized amorphous calcium phosphate for bone repair.

Traditional shape memory polymers (SMPs) could avoid large volume trauma during implantation; however, for bone repair, scaffolds with high porosity and biomineralization are essential to promote bone regeneration. A novel porous composite scaffold with high biomineralization activity was developed by sequential gas foaming and a freeze-drying method. The results showed that the cross-linked block structure of the polymer matrix presented excellent shape memory properties, and osteogenesis was promoted by citrate functionalized amorphous calcium phosphate (CCACP). CCACP improved the mechanical strength of the scaffold, and the synergistic effect of CCACP and PEG promotes hydrophilicity and further promoted cell adhesion. Bending experiments indicated that the shape-memory effect of the scaffolds could be varied by varying the CCACP content. In addition, hydroxyapatite deposition was sped up as CCACP accelerated the mineralization of the scaffolds. Moreover, the result of the CCK-8 assessment suggested that composite scaffolds exhibited high biocompatibility, and the cells extended out abundant filopodia to adhere onto the scaffolds. In rat bone defect models, the obtained scaffolds promoted new bone formation compared to the control group. The developed composite scaffolds show potential for minimally invasive bone repair application.

Porous Electroactive and Biodegradable Polyurethane Membrane through Self-Doping Organogel.

In order to improve the processability of conductive polyurethane (CPU) containing aniline oligomers, a new CPU containing aniline trimer (AT) and l-lysine (PUAT) are designed and synthesized. Further, the 3D porous PUAT membranes have been prepared by a simple gel cooperated with freeze-drying method. Chemical testings and conductive properties testify a self- doping model of PUAT based on the rich electronic l-lysine and electroaffinity AT moities. The self-doping behavior further endows the PUAT copolymers specific characteristics such as high electrical conductivity and the formation of the polaron lattice like-structure in good solvent dimethyl sulfoxide. The combination of organogel and freeze-drying could prevent the collapse of pore structure when the copolymers are molded as membranes. The synergistic effect of l-lysine and AT components has a strong influence on the dissolution, degradation, thermal stability, and mechanical properties of PUAT. The excellent properties of PUAT would broad the application of conductive polymers in biomedicine field.

The in vitro evaluation of antibacterial efficacy optimized with cellular apoptosis on multi-functional polyurethane sealers for the root canal treatment.

To solve the high instances of failure caused by endodontic reinfection, herein, an improved root filling material was produced to meet the multi-functional demand of sealers for root canal therapy. In this study, polyurethane (PU)-based nanocomposites were prepared by loading bismuth oxide, hydroxyapatite and antibacterial agents, namely Ag3PO4 and ZnO nanoparticles, which were named CP-Ag and CP-Zn sealers, respectively. A parallel biological evaluation at bacterial and cellular levels was performed to determine the fate of the different components of the PU-based sealers. Furthermore, the composition of sealers was quantified by screening their antibacterial activity and apoptotic factors, considering the potential toxicity of the nanoparticles and high dosage of metals. The in vitro optimization investigation was conducted systematically against Streptococcus mutans and Staphylococcus aureus, including bacteriostatic and dynamic tests, and the expression of the B-cell lymphoma-2 gene family and caspase proteases in the mitochondria-mediated apoptotic pathway was evaluated using the commercial AH Plus® and Apexit® Plus sealers for comparison. Additionally, the physical properties and sealing ability of sealers were assessed. The results showed that all PU-based sealers could meet the requirements of ISO 6876:2012 for root canal sealing materials. Based on the evaluation system, CP-Zn sealers expressed longer lasting antibacterial activity and lower toxic effect on cells compared to CP-Ag sealers. Especially, the CP-Zn5 sealer exhibited selective antimicrobial efficacy and hypo-toxicity, which were better than that of the two commercial sealers. According to the two-dimensional and three-dimensional methods, the good sealing ability of the CP-Zn5 sealer is the same as the excellent filling characters of AH Plus, which adapts to irregular root canals.

A "dual-guide" bioinspired drug delivery strategy of a macrophage-based carrier against postoperative triple-negative breast cancer recurrence.

Recurrence after tumor resection is mainly caused by post-operative inflammation and residual cancer cells, which is a serious obstacle to breast cancer treatment. Traditional nanoparticles rely primarily on the enhanced permeability and retention (EPR) effect in well-vascularized tumors. In this study, a macrophage-based carrier is designed to enhance the efficiency of targeting to recurrent tumors through a "dual-guide" strategy. After tumor resection, a burst of inflammatory factors occurs in the resection wound, which can recruit monocytes/macrophages rapidly. Combined with the tropism of monocyte chemoattractant protein, a large number of macrophage-mediated carriers will be recruited to surgical recurrence sites. Octaarginine (RRRRRRRR, R8)-modified liposomes in macrophages contain two agents with different pharmacological mechanisms, paclitaxel (PTX) and resveratrol (Res), which have enhanced therapeutic effects. In vitro study demonstrated that macrophage-mediated carriers approach 4 T1 cells through an inflammatory gradient and reach recurrence tumors through a "dual-guide" strategy. Then, membrane fusion and inflammation-triggered release deliver the drug into the recurrent tumor cells. In vivo experiments show that macrophage-based carriers exhibit effective tumor-targeting ability, especially in post-operation situations. More importantly, macrophage-mediated liposomes encapsulated with PTX and Res inhibit tumor recurrence in both ectopic and orthotopic 4 T1 post-operative recurrence models.

A stabilized retro-inverso peptide ligand of transferrin receptor for enhanced liposome-based hepatocellular carcinoma-targeted drug delivery.

The application of tumor targeting ligands to the treatment of cancer holds promise for improving efficacy and reducing toxicity. LT7 (L(HAIYPRH)) peptide, a phage display-selected peptide, exhibited high binding affinity to transferrin receptor (TfR) overexpressed on tumor cells. However, its in vivo tumor targeting efficiency was impaired due to enzymatic degradation in blood circulation. To improve the stability and targeting ability, a retro-inverso analogue of LT7 peptide, named DT7 peptide (D(HRPYIAH)), was designed for targeted therapy of hepatocellular carcinoma. The result of computer simulation predicted that DT7 bound to TfR protein more efficiently than LT7, and this prediction was confirmed experimentally by surface plasmon resonance (SPR). Ex vivo stability experiment demonstrated that DT7 possessed stronger ability against proteolysis than LT7 in fresh mouse serum. We further prepared DT7-, LT7-, and transferrin (Tf)-modified liposomes (DT7-LIP, LT7-LIP, and Tf-LIP, respectively). DT7-LIP showed a significantly stronger in vitro targeting ability than LT7-LIP and Tf-LIP under normal condition and simulated biological condition. In addition, the in vitro antitumor effect of DTX-loaded DT7-LIP was markedly enhanced in comparison to DTX-loaded LT7-LIP and DTX-loaded Tf-LIP. In vivo imaging indicated that DT7-LIP had better tumor accumulation than LT7-LIP and Tf-LIP. For in vivo antitumor studies, the tumor growth rate of mice treated with DTX-loaded DT7-LIP was significantly inhibited compared to that in mice treated with DTX-loaded LT7-LIP and DTX-loaded Tf-LIP. Overall, this study verified the potential of the stable DT7 peptide in improving the efficacy of docetaxel in the treatment of hepatocellular carcinoma. STATEMENT OF SIGNIFICANCE: A phage display library-selected LT7 (L(HAIYPRH)) peptide exhibited high affinity to transferrin receptor (TfR). However, its bioactivity was impaired in vivo as L-peptides are susceptible to degradation by proteolytic enzymes. Here, we designed a retro-inverso peptide DT7(D(HRPYIAH)) and demonstrated its increased serum stability and higher binding affinity to TfR. A stabilized targeted drug delivery system was further constructed by modified DT7 peptide on the surface of liposomes. The data indicated that DT7 peptide-modified liposomes exhibited higher targeting ability in vitro and in vivo. More importantly, DT7-modified liposomes demonstrated positive preclinical significance in enhancing the therapeutic effects against hepatocellular carcinoma.

Enhanced Melanoma-Targeted Therapy by "Fru-Blocked" Phenyboronic Acid-Modified Multiphase Antimetastatic Micellar Nanoparticles.

Metastasis remains the main driver of mortality in patients suffering from cancer because of the refractoriness resulting from the multi-phase metastatic cascade. Herein, a multifunctional self-delivering PBA-LMWH-TOS nanoparticle (PLT NP) is established that acts as both nanocarrier and anti-metastatic agent with effects on most hematogenous metastases of cancers. The hydrophilic segment (low molecular weight heparin, LMWH) inhibits the interactions between tumor cells and platelets. The hydrophobic segment (d-α-tocopheryl succinate, TOS) could inhibit the expression of matrix metalloproteinase-9 (MMP-9) in B16F10 cells which is first reported in this article. Surprisingly, even the blank NPs showed excellent anti-metastatic capacity in three mouse models by acting on different phases of the metastatic cascade. Moreover, the overexpression of sialic acid (SA) residues on tumor cells is implicated in the malignant and metastatic phenotypes of cancers. Thus, these 3-aminophenylboronic acid (PBA)-modified doxorubicin (DOX)-loaded NPs offer an efficient approach for the treatment of both solid melanomas and metastases. Furthermore, a simple pH-sensitive "Fructose (Fru)-blocking" coping strategy is established to reduce the NP distribution in normal tissues and distinctly increases the accumulation in melanoma tumors. These micellar NPs consisting of biocompatible materials offer a promising approach for the clinical therapy of highly invasive solid tumors and metastases.

Efficient siRNA transfer to knockdown a placenta specific lncRNA using RGD-modified nano-liposome: A new preeclampsia-like mouse model.

Preeclampsia is one of the most serious pregnancy complications. Many animal models have already been developed by researchers to study the pathogenesis and treatment of preeclampsia. However, most of these animal models were established by systemic administration or by surgery in the uterine cavity, which could lead to unwanted systemic toxicity or operative wounds and affect the accuracy of the results. Because of the high expression level of integrin αvß3 on the placenta, arginine-glycine-aspartic acid peptide (RGD) modified PEGylated cationic liposome (RGD-Lip) was designed as a novel gene delivery system to target the placenta safely and efficiently, and a new animal model of preeclampsia was established through targeting of long noncoding RNA (lncRNA). The results of cellular uptake and endosomal localization showed that RGD-Lip enhanced cellular uptake and endosomal escape of small interfering RNA (siRNA) on HTR-8/SVneo. In vivo imaging revealed that RGD-Lip was selectively delivered to the placenta. Additionally, H19x siRNA was efficiently transferred into the placenta of C57BL/6 mice via the injection of H19x siRNA-loaded RGD-Lip, which could result in the occurrence of preeclampsia-like symptoms. In summary, RGD-Lip provided a platform to efficiently deliver siRNA to the placenta, and a new preeclampsia-like mouse model was developed targeting placenta enriched/specific genes, including noncoding RNAs.

Dual Receptor Targeting Cell Penetrating Peptide Modified Liposome for Glioma and Breast Cancer Postoperative Recurrence Therapy.

PURPOSE: Cell penetrating peptides (CPPs) were widely used as motifs for drug delivery to tumor. In former study, an RGD reverse sequence dGR was used to develop active-targeting liposome R8dGR-Lip, which showed well penetrating ability and treatment efficiency on glioma model. However, recurrence after tumor resection caused by post-operative residual cancer cells was a huge obstacle in tumor treatment. In consideration of the effective anti-cancer effect of PTX-R8dGR-Lip when treating glioma in former study, we decide to evaluate its pharmacodynamics on tumor resection models, which were more invasive and resistant. METHOD: In vitro, the effectiveness of PTX-R8dGR-Lip in reducing tumor initiating cell (TIC) was investigated using mammosphere formation. In vivo, the inhibition efficiency of PTX-R8dGR-Lip on C6 glioma recurrence and 4 T1 breast cancer recurrence model were evaluated, including tumor bioluminescence imaging, survival rate and immumohistochemical staining, etc.. RESULTS: C6 mammosphere formation rate of PTX-R8dGR-Lip group was 48.06 ± 2.72%, and 4 T1 mammosphere formation rate of PTX-R8dGR-Lip group was 39.51 ± 4.02% when PBS group was set as 100%. C6 and 4 T1 bioluminescent tumor resected model were established, then effectiveness of different PTX-loaded preparations were evaluated on these two models. PTX-R8dGR-Lip could obviously inhibit tumor recurrence, prolong survival rate and reduce tumor tissue invasion. CONCLUSION: PTX-R8dGR-Lip could reduce post-operative recurrence rate, prolong survival time, and decrease the proliferation of residual cancer cells through regulating the expression of recurrence-related cytokines.

A tumor-activatable particle with antimetastatic potential in breast cancer via inhibiting the autophagy-dependent disassembly of focal adhesion.

In attempts to explore the role of autophagy in breast cancer metastasis, we here report a tumor-activatable particle (named as "D/PSP@CQ/CaP") with the ability of efficient autophagy inhibition. D/PSP@CQ/CaP was prepared by coprecipitating chloroquine phosphate (CQ) with calcium chloride, in the form of chloroquine-calcium phosphate coprecipitate (CQ/CaP), onto the surface of a deep-tumor-penetrating doxorubicine (DOX)-loading core particle (named as "D/PSP"). CQ/CaP could partly disintegrate and release CQ within tumor microenvironment and totally be dissolved within lysosomes. Paxillin is a key component of focal adhesion which functions to anchor tumors cells within the primary tumor for limiting cancer cells' detachment from the primary tumor. We tested that autophagy inhibition caused by CQ released from CQ/CaP could reduce the degradation of paxillin by 2.9 folds in vitro and 2.5 folds in vivo (vs. Control), respectively. Thus metastasis could be influenced by exploiting autophagy-dependent paxillin degradation. Data analysis together proved that D/PSP@CQ/CaP decreased the cancer metastatic extent by 7.5 folds (vs. Control) on mice model via inhibiting the autophagy-dependent disassembly of focal adhesion. At the same time, the growth rate of tumors treated by D/PSP@CQ/CaP was inhibited by 9.1 folds (vs. Control), which could be attributed to its effective tumor drug delivery.

Enhanced glioma therapy by synergistic inhibition of autophagy and tyrosine kinase activity.

Autophagy is a lysosomal degradation pathway that acts as a cytoprotective mechanism causing treatment resistance in various cancer cells. Recent studies showed that hydroxychloroquine can inhibit the latter step of autophagy and therefore enhance the anti-glioma efficiency of ZD6474, a tyrosine kinase inhibitor. However, the nonselective distribution of ZD6474 in vivo and the low penetrating ability of hydroxychloroquine when crossing the blood-brain barrier restrict their clinical use in glioma therapy. Here we coencapsulated ZD6474 and hydroxychloroquine into R6dGR peptide-modified liposomes (R6dGR-Lip) which can specifically recognize both integrin αvß3 and neuropilin-1 receptors that are highly expressed on the endothelial cells and glioma cells. R6dGR significantly enhanced the brain targeting and overcame the blood-brain barrier. Our results confirmed that loading hydroxychloroquine into R6dGR-Lip blocked autophagic flux more efficiently than free hydroxychloroquine in glioma cells and significantly sensitized glioma cells to ZD6474-induced cell death in vitro and in vivo. The coencapsulated R6dGR-modified liposomes (ZD6474/HCQ-R6dGR-Lip) prolonged the medium survival time of intracranial C6 glioma bearing mice by 1.2-fold compared with ZD6474-R6dGR-Lip, 1.5-fold compared with free ZD6474/HCQ, and 1.8-fold compared with free ZD6474, exhibiting a synergistic therapeutic effect. Therefore, ZD6474/HCQ-R6dGR-Lip is presented as a potential strategy which could be further used for efficient anti-glioma therapy.

Cell-penetrating peptides induce apoptosis and necrosis through specific mechanism and cause impairment of Na+-K+-ATPase and mitochondria.

Cell-penetrating peptides (CPPs) are widely used in the development of various drug delivery systems because of their ability of penetrating plasma membrane. However, the safety of their application remains largely unknown. In this study, we found that the incubation of two main kinds of CPPs with human normal liver cells could cause the occurrence of apoptosis and necrosis, then the detailed apoptosis-related protein were detected out. To discover the specific way which leads to these results, several methods were used in this study. Several cytokines, such as Caspase3 and Bcl-2, were detected to prove that the damage happened after treated with different CPPs. Then shielding the positive charge of TAT and R8, depletion of Na+ in culturing medium and addition of several inhibitors of specific ATPase site were used to investigate whether the cytotoxicity were charge-dependent and ATPase-related. Furthermore, the membrane potential of mitochondria and the leakage of mitochondrial cytochrome c were detected after treated with CPPs to investigate the damage on mitochondria. In general, our results assess the cytotoxicity caused by two main kinds of CPPs and reveal the clear mechanism of how it occurs. This study reveals the essence of cytotoxicity caused by CPPs, and the methods we followed can be used to evaluate the biocompatibility of new-designed CPPs, which makes the application of CPPs better and safer.

Significantly enhanced tumor cellular and lysosomal hydroxychloroquine delivery by smart liposomes for optimal autophagy inhibition and improved antitumor efficiency with liposomal doxorubicin.

Hydroxychloroquine (HCQ) inhibits autophagy and therefore can sensitize some cancer cells to chemotherapy, but the high doses required limit its clinical use. Here we show that loading HCQ into liposomes (HCQ/Lip) decorated with a pH-sensitive TH-RGD targeting peptide (HCQ/Lip-TR) can concentrate HCQ in B16F10 tumor cells and lysosomes. HCQ/Lip-TR was efficiently internalized as a result of its ability to bind ITGAV-ITGB3/integrin αvß3 receptors highly expressed on the tumor cell surface and to undergo charge reversal from anionic at pH 7.4 to cationic at pH 6.5. Studies in vitro at pH 6.5 showed that the intracellular HCQ concentration was 35.68-fold higher, and lysosomal HCQ concentration 32.22-fold higher, after treating cultures with HCQ/Lip-TR than after treating them with free HCQ. The corresponding enhancements observed in mice bearing B16F10 tumors were 15.16-fold within tumor cells and 14.10-fold within lysosomes. HCQ/Lip-TR was associated with milder anemia and milder myosuppressive reductions in white blood cell and platelet counts than free HCQ, as well as less accumulation in the small intestine, which may reduce risk of intestinal side effects. In addition, co-delivering HCQ/Lip-TR with either free doxorubicin (DOX) or liposomal DOX improved the ability of DOX to inhibit tumor growth. Biochemical, electron microscopy and immunofluorescence experiments confirmed that HCQ/Lip-TR blocked autophagic flux in tumor cells. Our results suggest that loading HCQ into Lip-TR liposomes may increase the effective concentration of the inhibitor in tumor cells, allowing less toxic doses to be used.

Characterization of Lignanamides from Hemp (Cannabis sativa L.) Seed and Their Antioxidant and Acetylcholinesterase Inhibitory Activities.

Hemp seed is known for its content of fatty acids, proteins, and fiber, which contribute to its nutritional value. Here we studied the secondary metabolites of hemp seed aiming at identifying bioactive compounds that could contribute to its health benefits. This investigation led to the isolation of 4 new lignanamides, cannabisin M (2), cannabisin N (5), cannabisin O (8), and 3,3'-demethyl-heliotropamide (10), together with 10 known lignanamides, among which 4 was identified for the first time from hemp seed. Structures were established on the basis of NMR, HR-MS, UV, and IR as well as by comparison with the literature data. Lignanamides 2, 7, and 9-14 showed good antioxidant activity, among which 7, 10, and 13 also inhibited acetylcholinesterase in vitro. The newly identified compounds in this study add to the diversity of hemp seed composition, and the bioassays implied that hemp seed, with lignanamides as nutrients, may be a good source of bioactive and protective compounds.