Synthetic Helical Polypeptide as a Gene Transfection Enhancer.

The relatively low transfection efficiency limits further application of polymeric gene carriers. It is imperative to exploit a universal and simple strategy to enhance the gene transfection efficiency of polymeric gene carriers. Herein, we prepared a cationic polypeptide poly(γ-aminoethylthiopropyl-l-glutamate) (PALG-MEA, termed PM) with a stable α-helical conformation, which can significantly improve the gene transfection efficiency of cationic polymers. PM can be integrated into polymeric gene delivery systems noncovalently through electrostatic interactions. With the assistance of PM, polymeric gene delivery systems exhibited excellent cellular uptake and endosomal escape, thereby enhancing transfection efficiency. The transfection enhancement effect of PM was applicable to a variety of cationic polymers such as polyethylenimine (PEI), poly-l-lysine (PLL), and polyamidoamine (PAMAM). The ternary gene delivery system PM/pshVEGF/PEI exhibited an excellent antitumor effect against the B16F10 tumor model. Moreover, we demonstrated that PM could also enhance the delivery of gene editing systems (sgRNA-Cas9 plasmids). This work provides a facile and effective strategy for constructing polymeric gene delivery systems with a high transfection efficiency.

Rationally Designed Polymer Conjugate for Tumor-Specific Amplification of Oxidative Stress and Boosting Antitumor Immunity.

The crosstalk between tumor and stroma cells is a central scenario in the tumor microenvironment (TME). While the predominant effect of tumor cells on immune cells is establishing an immunosuppressive context, tumor cell death at certain conditions will boost antitumor immunity. Herein, we report a rationally designed tumor specific enhanced oxidative stress polymer conjugate (TSEOP) for boosting antitumor immunity. The TSEOP is prepared by Passerini reaction between cinnamaldehyde (CA), 4-formylbenzeneboronic acid pinacol ester, and 5-isocyanopent-1-yne, followed by azide-alkyne click reaction with poly(l-glutamic acid)-graft-poly(ethylene glycol) monomethyl ether (PLG-g-mPEG). Under tumor stimuli condition, CA and quinone methide (QM) are quickly generated, which cooperatively induce strong oxidative stress, immunogenic tumor cell death (ICD), and activation of antigen presenting cells. In vivo studies show that the TSEOP treatment boosts tumor-specific antitumor immunity and eradicates both murine colorectal and breast tumors. This study should be inspirational for designing polymers as immunotherapeutics in cancer therapy.

A large deletion spanning PITX2 and PANCR in a Chinese family with Axenfeld-Rieger syndrome.

Purpose: To identify the genetic cause in a four-generation Chinese family with Axenfeld-Rieger syndrome (ARS). Methods: The family members received clinical examinations of the eye, tooth, periumbilical skin, and heart. Sanger sequencing and whole-exome sequencing (WES) were performed to screen potential mutations. The genomic deletion region around the PITX2 gene was estimated from single nucleotide polymorphism (SNP) data from WES and then confirmed with "quantitative PCR (qPCR) using a set of primers. The DNA breakpoint was further identified with long-range PCR and Sanger sequencing. Results: Symptoms including anterior segment dysplasia of the eye (iris dysplasia, multiple pupils, and posterior embryotoxon), dental dysplasia, and periumbilical skin redundancy were present in all of the affected individuals. Three of them had glaucoma. Corneal abnormalities (inferior sclerocornea, corneal endothelial dystrophy, and central corneal scar) were seen in most of the affected individuals. Cataract, limited eye movement, electrocardiographic abnormalities, intellectual disability, and recurrent miscarriages were observed in some of the affected individuals. No mutations in the coding and exon-intron adjacent regions of the PITX2 and FOXC1 genes were identified with Sanger sequencing. According to the SNP data from WES, we suspected that there might be a deletion region (at most 1.6 Mb) around the PITX2 gene. With the use of qPCR and long-range PCR, we identified a 53,840 bp deletion (chr4: 111,535,454-111,588,933) spanning PITX2 and PANCR. The genomic deletion cosegregated with the major ARS symptoms observed in the family members. Conclusions: With the help of WES, qPCR, and long-range PCR, we identified a genomic deletion encompassing PITX2 and the adjacent noncoding gene PANCR in a Chinese family with ARS. The clinical features of the affected individuals are reported. This work may broaden understanding of the phenotypic and mutational spectrums related to ARS.

Improving Plasma Stability and Bioavailability In Vivo of Gemcitabine Via Nanoparticles of mPEG-PLG-GEM Complexed with Calcium Phosphate.

PURPOSE: Despite being widely used for the treatment of several solid tumors, Gemcitabine (GEM) exhibits several suboptimal pharmacokinetic properties. Therefore, the design of nanoparticle delivery systems is a promising strategy to enhance GEM pharmacokinetic properties. METHODS: In this work, the polymeric material methoxy poly(ethylene glycol)-block-poly(L-glutamic acid)-graft-gemcitabine (mPEG-b-PLG-g-GEM) was synthesized through the covalent conjugation of GEM with the carboxylic group of methoxy poly(ethylene glycol)-block-poly (L-glutamic acid) (mPEG-b-PLG) (mPEG113, Mn = 5000). mPEG-PLG-GEM/CaP nanoparticles were prepared through the simple mixing of calcium and phosphate/mPEG-PLG-GEM solutions. mPEG-PLG-GEM was embedded in the calcium phophate (CaP) backbone via electrostatic interactions. RESULTS: After incubation in plasma at 37°C for 24 h, gemcitabine was degraded by 24.6% for the mPEG-PLG-GEM, 14.7% for the mPEG-PLG-GEM/CaP nanoparticles, and 90% for the free gemcitabine solution. It was observed that mPEG-PLG-GEM and mPEG-PLG-GEM/CaP improved the area-under-curve (AUC) values by 5.26-fold and 6.33-fold compared to free drug, respectively. CONCLUSION: The amide bond linked gemcitabine polymers was able to protect GEM from cytidine deaminase degradation in vivo, and the skeleton formed by the calcium phosphate enhanced the stability and prolonged the half-life of GEM. Importantly, mPEG-PLG-GEM/CaP nanoparticles elevated the GEM plasma concentration in an animal model.

Development and Application of an MSALL-Based Approach for the Quantitative Analysis of Linear Polyethylene Glycols in Rat Plasma by Liquid Chromatography Triple-Quadrupole/Time-of-Flight Mass Spectrometry.

Polyethylene glycols (PEGs) are synthetic polymers composed of repeating ethylene oxide subunits. They display excellent biocompatibility and are widely used as pharmaceutical excipients. To fully understand the biological fate of PEGs requires accurate and sensitive analytical methods for their quantitation. Application of conventional liquid chromatography-tandem mass spectrometry (LC-MS/MS) is difficult because PEGs have polydisperse molecular weights (MWs) and tend to produce multicharged ions in-source resulting in innumerable precursor ions. As a result, multiple reaction monitoring (MRM) fails to scan all ion pairs so that information on the fate of unselected ions is missed. This Article addresses this problem by application of liquid chromatography-triple-quadrupole/time-of-flight mass spectrometry (LC-Q-TOF MS) based on the MSALL technique. This technique performs information-independent acquisition by allowing all PEG precursor ions to enter the collision cell (Q2). In-quadrupole collision-induced dissociation (CID) in Q2 then effectively generates several fragments from all PEGs due to the high collision energy (CE). A particular PEG product ion (m/z 133.08592) was found to be common to all linear PEGs and allowed their total quantitation in rat plasma with high sensitivity, excellent linearity and reproducibility. Assay validation showed the method was linear for all linear PEGs over the concentration range 0.05-5.0 µg/mL. The assay was successfully applied to the pharmacokinetic study in rat involving intravenous administration of linear PEG 600, PEG 4000, and PEG 20000. It is anticipated the method will have wide ranging applications and stimulate the development of assays for other pharmaceutical polymers in the future.

Inhibiting Solid Tumor Growth In Vivo by Non-Tumor-Penetrating Nanomedicine.

Nanomedicine (NM) cannot penetrate deeply into solid tumors, which is partly attributed to the heterogeneous microenvironment and high interstitial fluid pressure of solid tumors. To improve NM efficacy, there has been tremendous effort developing tumor-penetrating NMs by miniaturizing NM sizes or controlling NM surface properties. But progress along the direction of developing tumor penetrating nanoparticle has been slow and improvement of the overall antitumor efficacy has been limited. Herein, a novel strategy of inhibiting solid tumor with high efficiency by dual-functional, nontumor-penetrating NM is demonstrated. The intended NM contains 5,6-dimethylxanthenone-4-acetic acid (DMXAA), a vascular-disrupting agent, and doxorubicin (DOX), a cytotoxic drug. Upon arriving at the target tumor site, sustained release of DMXAA from NMs results in disruption of tumor vessel functions, greatly inhibiting the interior tumor cells by cutting off nutritional supply. Meanwhile, the released DOX kills the residual cells at the tumor exterior regions. The in vivo studies demonstrate that this dual-functional, nontumor penetrating NM exhibits superior anticancer activity, revealing an alternative strategy of effective tumor growth inhibition.

N-Isopropylacrylamide Modified Polyethylenimines as Effective siRNA Carriers for Cancer Therapy.

N-isopropylacrylamide modified PEI (PEN) was synthesized via Michael addition and was developed as an efficient siRNA delivery system both in vitro and in vivo. PEN showed significant enhanced cytocompatibility compared with commercial PEI-25k. The complexation of PEN with siRNA was studied by gel retardation, particle size and zeta potential measurement. The in vitro transfection ability of PEN was measured by qRT-PCR assay, and achieved obviously enhanced gene silencing efficiency compared with PEI-25k. The confocal imaging and flow cytometric analysis further validated its excellent intracellular trafficking ability. For antitumor treatment experiment, PEN mediated siVEGF showed obviously therapeutic effects for the treatment of CT26 tumor. Therefore, the present study demonstrated a useful strategy for constructing efficient siRNA delivery vehicles for antitumor therapy.

Stable loading and delivery of disulfiram with mPEG-PLGA/PCL mixed nanoparticles for tumor therapy.

Disulfiram (DSF) showed great potential in an in vitro tumor therapy study; however, those results could not be applied to an in vivo study due to the extreme instability of DSF in blood. Here, we describe a system of methoxy poly(ethylene glycol)-b-poly(lactide-co-glycolide)/poly(ε-caprolactone) (mPEG-PLGA/PCL) mixed nanoparticles (NPs) for DSF loading and delivery. By adjusting the mPEG-PLGA/PCL content ratios, the DSF loading capacity increased to 7.8%, while the hydrodynamic radii of the NPs were around 50-100nm. The DSF-loaded NPs showed high stability in distilled water and 10% serum-containing phosphate buffered saline. The NPs efficiently protected DSF from degradation while maintaining its anti-tumor properties. Furthermore, a pharmacokinetics study demonstrated that NP delivery system enhanced the DSF concentration in the blood after tail vein injection. Finally, DSF delivery using this model effectively slowed the growth of a 4T1 murine xenograft tumor. FROM THE CLINICAL EDITOR: The anti-tumor efficacy of the anti-alcoholic drug disulfiram has been known for some time. However, its use in the clinical setting is limited due to the underlying instability of the drug. In this study, the authors utilized a nanocarrier system of mPEG-PLGA/PCL for the delivery of this drug. The promising results may allow encapsulation of other drugs.

Charge-conversional PEG-polypeptide polyionic complex nanoparticles from simple blending of a pair of oppositely charged block copolymers as an intelligent vehicle for efficient antitumor drug delivery.

A tumor-acidity-activated charge-conversional polyionic complex nanoparticle system was developed by simply mixing a pair of oppositely charged block copolymers: anionic methoxy poly(ethylene glycol)-b-poly(l-glutamic acid-co-l-phenylalanine) (mPEG-b-P(Glu-co-Phe)) and cationic methoxy poly(ethy1ene glycol)-b-poly(l-lysine-co-l-phenylalanine) (mPEG-b-P(Lys-co-Phe)). The nanoparticles could stay negatively charged under normal physiological pH value and reverse the surface charge to positive at the tumor extracellular environment. Doxorubicin (DOX) was encapsulated into the nanoparticles fabricated by a self-assembly process, and the DOX-loaded polyionic complex nanoparticles (DOX-NPs) retained the charge-conversional property. In vitro DOX release study demonstrated that DOX release was promoted by the significantly increased acidity in endosomes and lysosomes (pH ≈ 5-6). Cellular uptake studies confirmed that the DOX-NPs could be more effectively internalized by cells at the tumor extracellular pH value. In vitro cytotoxicity assays demonstrated that the polyionic complex nanoparticles had good biocompatibility, and DOX-NPs showed efficient cell proliferation inhibition to HeLa and A549 tumor cells. Maximum tolerated dose (MTD) studies revealed that DOX-NPs had a significantly higher MTD (more than 25 mg of DOX/kg) in mice compared to that for free DOX (5 mg of DOX/kg). Furthermore, DOX-NPs showed superior antitumor activity and reduced side toxicity compared to free DOX in A549 tumor bearing nude mice.

Co-delivery of Plinabulin and Tirapazamine boosts anti-tumor efficacy by simultaneously destroying tumor blood vessels and killing tumor cells.

It is imperative to optimize chemotherapy for heightened anti-tumor therapeutic efficacy. Unrestrained tumor cell proliferation and sustained angiogenesis are pivotal for cancer progression. Plinabulin, a vascular disrupting agent, selectively destroys tumor blood vessels. Tirapazamine (TPZ), a hypoxia-activated prodrug, intensifies cytotoxicity in diminishing oxygen levels within tumor cells. Despite completing Phase III clinical trials, both agents exhibited modest treatment efficiency due to dose-limiting toxicity. In this study, we employed methoxy poly(ethylene glycol)-b-poly(D,L-lactide) (mPEG-b-PDLLA) to co-deliver Plinabulin and TPZ to the tumor site, concurrently disrupting blood vessels and eliminating tumor cells, addressing both symptoms and the root cause of tumor progression. Plinabulin was converted into a prodrug with esterase response (PSM), and TPZ was synthesized into a hexyl chain-containing derivative (TPZHex) for effective co-delivery. PSM and TPZHex were co-encapsulated with mPEG-b-PDLLA, forming nanodrugs (PT-NPs). At the tumor site, PT-NPs responded to esterase overexpression, releasing Plinabulin, disrupting blood vessels, and causing nutritional and oxygen deficiency. TPZHex was activated in response to increased hypoxia, killing tumor cells. In treating 4T1 tumors, PT-NPs demonstrated enhanced therapeutic efficacy, achieving a 92.9 % tumor suppression rate and a 20 % cure rate. This research presented an innovative strategy to enhance synergistic efficacy and reduce toxicity in combination chemotherapy.

Tumor Microenvironment Remodeling-Mediated Sequential Drug Delivery Potentiates Treatment Efficacy.

Toll-like receptor 7/8 agonists, such as imidazoquinolines (IMDQs), are promising for the de novo priming of antitumor immunity. However, their systemic administration is severely limited due to the off-target toxicity. Here, this work describes a sequential drug delivery strategy. The formulation is composed of two sequential modules: a tumor microenvironment remodeling nanocarrier (poly(l-glutamic acid)-graft-methoxy poly(ethylene glycol)/combretastatin A4, termed CA4-NPs) and an immunotherapy nanocarrier (apcitide peptide-decorated poly(l-glutamic acid)-graft-IMDQ-N3 conjugate, termed apcitide-PLG-IMDQ-N3). CA4-NPs, as a vascular disrupting agent, are utilized to remodel the tumor microenvironment for enhancing tumor coagulation and hypoxia. Subsequently, the apcitide-PLG-IMDQ-N3 could identify and target tumor coagulation through the binding of surface apcitide peptide to the GPIIb-IIIa on activated platelets. Afterward, IMDQ is activated selectively through the conversion of "-N3" to "-NH2" in the presence of hypoxia. The biodistribution results confirm their high tumor uptake of activated IMDQ (22.66%ID/g). By augmenting the priming and immunologic memory of tumor-specific CD8+ T cells, 4T1 and CT26 tumors with a size of ≈500 mm3 are eradicated without recurrence in mouse models.

Preparation of an Ultrahigh-DAR PDL1 monoclonal antibody-polymeric-SN38 conjugate for precise colon cancer therapy.

Antibody-drug conjugates (ADCs) are the most potent active tumor-targeting agents used clinically. However, the preparation of ADCs with high drug-to-antibody ratios (DARs) remains a major challenge. Herein, a Fab-nondestructive SN38-loaded antibody-polymeric-drug conjugate (APDC), aPDL1-NPLG-SN38, was prepared that had a DAR as high as 72 for the first time, by increased numbers of payload binding sites via the carboxyl groups of poly (l-glutamic acid) (PLG). The bonding of Fc-III-4C peptide with PLG-graft-mPEG/SN38 (Fc-NPLG-SN38) was achieved using a click reaction between azide and DBCO groups. The aPDL1-NPLG-SN38 conjugate was then synthesized by the high-affinity interaction between the Fc-III-4C peptide in Fc-NPLG-SN38 and the crystallizable fragment (Fc) of PDL1 monoclonal antibody (aPDL1). This approach avoided the potential deleterious effects on the Fab structure of the monoclonal antibody. The aqueous environment used in its preparation helped maintain monoclonal antibody recognition capability. Through the specific recognition by aPDL1 of PDL1 that is highly expressed on MC38 tumors, the accumulation of aPDL1-NPLG-SN38 in the tumors was 2.8-fold greater than achieved with IgG-NPLG-SN38 that had no active tumor-targeting capability. aPDL1-NPLG-SN38 exhibited excellent therapeutic properties in both medium-sized and large MC38 tumor animal models. The present study provides the details of a novel preparation strategy for SN38-loaded ADCs having a high DAR.

Preparation and Characterization Evaluation of Poly(L-Glutamic Acid)-g-Methoxy Poly(Ethylene Glycol)/Combretastatin A4/BLZ945 Nanoparticles for Cervical Cancer Therapy.

Purpose: Cervical cancer (CC) is a highly vascularized tumor with abundant abnormal blood vessel, which could be targeted by therapeutic strategies. Poly(L-glutamic acid)-g-methoxy poly(ethylene glycol)/combretastatin A4 (CA4)/BLZ945 nanoparticles (CB-NPs) have shown great potential as nano vascular disrupting agents (VDAs) in the realm of synergistic cancer therapy. Methods: In this study, we investigated the nanocharacteristics of CB-NPs, focusing on active pharmaceutical ingredients (API), as well as lyophilized samples combining API with protective agents (PAs). The in vivo efficacy of final sample (API + PAs) was evaluated. Results: The assembled sphere of API with complex core and thin-shell structure was confirmed. PAs were found to significantly influence in vivo efficacy. Collaborative efforts between API and PAs, namely mannitol and lactose, resulted in the most promising lyophilized sample, ie, the final sample (FS2) for CC therapy. Impressively, FS2 demonstrated an exceptional 100% cure rate on the CC U14-bearing mice model. Conclusion: FS2 has provided significant insights for cervical cancer therapy. It is also crucial to develop a comprehensive evaluation strategy for the formulation of nanomedicine, which has the potential to serve as a guideline for future clinical trials.

Formula optimization and in vivo study of poly(L-glutamic acid)-g-methoxy poly(ethylene glycol)/combretastatin A4/BLZ945 nanoparticles for cancer therapy.

Poly(L-glutamic acid)-g-methoxy poly(ethylene glycol)/Combretastatin A4 (CA4)/BLZ945 nanoparticles (CB-NPs) have shown great potential in synergistic cancer therapy. However, it is still unclear how the nanoparticles' formula, such as injection dose, active agent ratio, and drug loading content, affects the side effects and in vivo efficacy of CB-NPs. In this study, a series of CB-NPs with different BLZ945/CA4 (B/C) ratios and drug loading contents were synthesized and evaluated on a hepatoma (H22) tumor-bearing mice model. The injection dose and B/C ratio were found to have a significant influence on the in vivo anticancer efficacy. The CB-NPs 20 with B/C weight ratio of 0.45/1, and total drug loading content (B + C) of 20.7 wt%, showed the highest potential for clinical application. Systematic pharmacokinetics, biodistribution, and in vivo efficacy evaluation for CB-NPs 20 have been finished, which may provide significant instruction for medicine screening and clinical application.

Mannan-decorated pathogen-like polymeric nanoparticles as nanovaccine carriers for eliciting superior anticancer immunity.

Using nanotechnology for cancer vaccine design holds great promise because of the intrinsic feature of nanoparticles in being captured by antigen-presenting cells (APCs). However, there are still obstacles in current nanovaccine systems in achieving efficient tumor therapeutic effects, which could partially be attributed to the unsatisfactory vaccine carrier design. Herein, we report a mannan-decorated pathogen-like polymeric nanoparticle as a protein vaccine carrier for eliciting robust anticancer immunity. This nanovaccine was constructed as a core-shell structure with mannan as the shell, polylactic acid-polyethylenimine (PLA-PEI) assembled nanoparticle as the core, and protein antigens and Toll-like receptor 9 (TLR9) agonist CpG absorbed onto the PLA-PEI core via electrostatic interactions. Compared to other hydrophilic materials, mannan decoration could greatly enhance the lymph node draining ability of the nanovaccine and promote the capturing by the CD8+ dendritic cells (DCs) in the lymph node, while PLA-PEI as the inner core could enhance antigen endosome escape thus promoting the antigen cross-presentation. In addition, mannan itself as a TLR4 agonist could synergize with CpG for maximally activating the DCs. Excitingly, we observed in several murine tumor models that using this nanovaccine alone could elicit robust immune response in vivo and result in superior anti-tumor effects with 50% of mice completely cured. This study strongly evidenced that mannan decoration and a rationally designed nanovaccine system could be quite robust in tumor vaccine therapy.

Synthesis of amphiphilic alternating polyesters with oligo(ethylene glycol) side chains and potential use for sustained release drug delivery.

Novel amphiphilic alternating polyesters, poly((N-phthaloyl-l-glutamic anhydride)-co-(2-(2-(2-methoxyethoxy)ethoxy)methyl)oxirane) (P(PGA-co-ME(2)MO)), were synthesized by alternating copolymerization of PGA and ME(2)MO. The structures of the synthesized polyesters were characterized by (1)H NMR, (13)C NMR, FT-IR, and GPC analyses. Because of the presence of oligo(ethylene glycol) (OEG) side chains, the polyesters could self-assemble into thermosensitive micelles. Dynamic light scattering (DLS) showed that these micelles underwent thermoinduced size decrease without intermicellar aggregation. In vitro methyl thiazolyl tetrazolium (MTT) assay demonstrated that the polyesters were biocompatible to Henrietta Lacks (HeLa) cells, rendering their potential for drug delivery applications. Two hydrophobic drugs, rifampin and doxorubicin (DOX), were loaded into the polyester micelles and observed to be released in a zero-order sustained manner. The sustained release could be accelerated in lower pH or in the presence of proteinase K, due to the degradation of the polyester under these conditions. Remarkably, in vitro cell experiments showed that the polyester micelles accomplished fast release of DOX inside cells and higher anticancer efficacy as compared with the free DOX. With enhanced stability during circulation condition and accelerated drug release at the target sites (e.g., low pH or enzyme presence), these novel polyesters with amphiphilic structures are promising to be used in sustained release drug delivery systems.

Poly(L-Glutamic Acid)-Drug Conjugates for Chemo- and Photodynamic Combination Therapy.

Despite the polymeric vascular disrupting agent (poly(L -glutamic acid)-graft-methoxy poly(ethylene glycol)/combretastatin A4) nanoparticles can efficiently inhibit cancer growth, their further application is still a challenge owing to the tumor recurrence and metastasis after treatment. In this study, two poly(L -glutamic acid)-drug conjugates for chemo-and photodynamic combination therapy are fabricated. PLG-g-mPEG-CA4 nanoparticles are prepared by combretastatin A4 (CA4) and poly(L -glutamic acid)-graft-methoxy poly(ethylene glycol) (PLG-g-mPEG) using the Yamaguchi esterification reaction. PLG-g-mPEG-TPP (TPP: 5, 10, 15, 20-tetraphenylporphyrin) nanoparticles are constructed using PLG-g-mPEG and amine porphyrin through condensation reaction between carboxyl group of PLG-g-mPEG and amino group of porphyrin. The results showed that PLG-g-mPEG-CA4 nanoparticles have good antitumor ability. PLG-g-mPEG-TPP nanoparticles can produce singlet oxygen under the laser irradiation. Moreover, the combined therapy of PLG-g-mPEG-CA4 and PLG-g-mPEG-TPP nanoparticles has higher antitumor effect than the single chemotherapy or the single photodynamic therapy in vitro. The combination of CA4 nondrug and photodynamic therapy provides a new insight for enhancing the tumor therapeutic effect with vascular disrupting agents and other therapy.

Self-Amplifying Nanotherapeutic Drugs Homing to Tumors in a Manner of Chain Reaction.

Active tumor-targeting drug delivery has great potency in cancer therapy. However, the targeting efficiency of traditional active tumor-targeting nanotherapeutic drugs is limited by the scarcity of their accessible targets/receptors in tumors. Here, a novel self-amplifying tumor-targeting strategy with a chain reaction mechanism is developed. A coagulation targeting peptide (GNQEQVSPLTLLKXC, termed A15)-decorated poly(L-glutamic acid)-graft-maleimide poly(ethylene glycol)/combretastatin A4 conjugate (A15-PLG-CA4) is prepared to obtain a self-amplifying nanotherapeutic platform homing to tumors. After administration to tumor-bearing mice, A15-PLG-CA4 starts a chain reaction cycle consisting of intratumoral hemorrhage, target FXIIIa amplification, blood clot binding, and CA4 release in tumors. In this way, A15-PLG-CA4 increases the level of its accessible targets (FXIIIa) in a manner of chain reaction. The FXIIIa activity at 8 h is 4.1-fold more than the one at 0 h in the C26 tumors treated with A15-PLG-CA4. The total CA4 concentration at 24 h is 2.9-fold more than the control. A15-PLG-CA4 shows a significantly higher antitumor effect against large C26 tumors (≈500 mm3 ) thanks to the remarkable tumor-targeting ability compared with the control. Therefore, this report highlights the potential of the self-amplifying tumor-targeting strategy in the development of next generation active tumor-targeting nanotherapeutic drugs for tumor therapy.

Cisplatin Loaded Poly(L-glutamic acid)-g-Methoxy Polyethylene Glycol Complex Nanoparticles Combined with Gemcitabine Presents Improved Safety and Lasting Anti-Tumor Efficacy in a Murine Xenograft Model of Human Aggressive B Cell Lymphoma.

Cisplatin (CDDP) is a highly effective anti-tumor drug with a broad spectrum of activity. However, the clinical efficacy of CDDP-containing regimens is yet unsatisfactory due to the severe dose-related toxicity of CDDP. In a previous study, CDDP nanoparticles (L-CDDP) forms a complex as CDDP with poly(L-glutamic acid)-g-methoxy poly(ethylene glycol) with improved safety compared to CDDP. Herein, a murine xenograft model of human aggressive B cell lymphoma (BCL) was established to explore anti-lymphoma efficiency of L-CDDP combined with GEM. BJAB cells represent an aggressive BCL, which were utilized to explore the anti-proliferative effect, cell apoptosis via CCK-8 test and flow cytometry technology, respectively. Toxicity experiment and the maximum tolerated dose (MTD) test were conducted in Kunming mice. Tumor inhibition experiment was conducted at the dose of MTD in SCID beige mice-bearing lymphoma. In this study, the loading capacity and encapsulating efficiency of CDDP in the L-CDDP was 18.3% and 89.7%, respectively, and the hydrodynamic diameter of the prepared L-CDDP was 20.6 nm. The CCK-8 data indicated that the anti-proliferative activity of monodrug groups (GEM, CDDP, L-CDDP) was dose- and time-dependent in BJAB cells. The synergistic effects in anti-lymphoma were detected in these two groups (GEM+CDDP, GEM + L-CDDP). Compared to control group, the proportion of apoptotic cells in experimental groups in BJAB cells was significantly higher at 48 h. Toxicity assays revealed that GEM + L-CDDP regimen had low hematological toxicity, hepatotoxicity, and nephrotoxicity. Tumor inhibition experiment demonstrated that GEM + L-CDDP group exhibited significant tumor-suppressing effects. Moreover, tumors continued to shrink in GEM + L-CDDP group, while these appeared to grow in the GEM + CDDP group. Finally, tumor necrosis was most prominent in the GEM + CDDP and GEM + L-CDDP groups, as assessed by hematoxylin-eosin staining. In conclusion, compared to CDDP, L-CDDP combined with GEM seriously induces BJAB cell apoptosis. Also, GEM + L-CDDP exhibits low hematotoxicity, hepatotoxicity, and nephrotoxicity. Importantly, GEM + L-CDDP presents lasting anti-lymphoma efficacy in a SCID beige mice-bearing lymphoma.

Polyethyleneimine-CpG Nanocomplex as an In Situ Vaccine for Boosting Anticancer Immunity in Melanoma.

Cancer immunotherapy is redefining the field of cancer therapy. However, current cancer immunotherapies are limited by insufficient immune activation, which results in low response rate. Herein, polyethyleneimine-CpG nanocomplex (CpG@PEI) is reported as an in situ vaccine for boosting anticancer immunity in melanoma. CpG, a Toll-like receptor (TLR) 9 agonist, can activate antigen-presenting cells and increase the expression of costimulatory molecules, while PEI can help to enhance the stability and cellular internalization of CpG. It is proved that PEI loading can significantly enhance the cellular internalization and immune stimulation ability of CpG, and the CpG@PEI nanocomplex can effectively inhibit murine B16F10 melanoma growth after intratumoral injection. Further analysis reveals that this CpG@PEI nanocomplex therapy elicits both innate and adaptive immunity, with much increased natural killer (NK) cells and T cells infiltration in the tumor, as well as CD80 expression on the dendritic cells (DCs). This study will inspire more attempts in directly using single nanoparticle-loaded pattern recognition receptor (PRR) agonists for cancer immunotherapy.