Design of pH-responsive antimicrobial peptide melittin analog-camptothecin conjugates for tumor therapy

Melittin,a classical antimicrobial peptide,is a highly potent antitumor agent.However,its significant toxicity seriously hampers its application in tumor therapy.In this study,we developed novel melittin analogs with pH-responsive,cell-penetrating and membranelytic activities by replacing arginine and lysine with histidine.After conjugation with camptothecin(CPT),CPT-AAM-1 and CPT-AAM-2 were capable of killing tumor cells by releasing CPT at low concentrations and disrupting cell membranes at high concentrations under acidic conditions.Notably,we found that the C-terminus of the melittin analogs was more suitable for drug conjugation than the N-terminus.CPT-AAM-1 significantly suppressed melanoma growth in vivo with relatively low toxicity.Collectively,the present study demonstrates that the development of antitumor drugs based on pH-responsive antimicrobial peptide-drug conjugates is a promising strategy.

Antibody-platinum(IV)prodrugs conjugates for targeted treatment of cutaneous squamous cell carcinoma

Antibody-drug conjugates(ADCs)are a new type of targeting antibodies that conjugate with highly toxic anticancer drugs via chemical linkers to exert high specificity and efficient killing of tumor cells,thereby attracting considerable attention in precise oncology therapy.Cetuximab(Cet)is a typical antibody that offers the benefits of good targeting and safety for individuals with advanced and inoperable cutaneous squamous cell carcinoma(cSCC);however,its anti-tumor activity is limited to a single use.Cisplatin(CisPt)shows good curative effects;however,its adverse effects and non-tumor-targeting ability are major drawbacks.In this study,we designed and developed a new ADC based on a new cytotoxic platinum(IV)prodrug(C8Pt(IV))and Cet.The so-called antibody-platinum(IV)prodrugs conjugates,named Cet-C8Pt(IV),showed excellent tumor targeting in cSCC.Specifically,it accurately delivered C8Pt(IV)into tumor cells to exert the combined anti-tumor effect of Cet and CisPt.Herein,metabolomic analysis showed that Cet-C8Pt(IV)promoted cellular apoptosis and increased DNA damage in cSCC cells by affecting the vitamin B6 metabolic pathway in tumor cells,thereby further enhancing the tumor-killing ability and providing a new strategy for clinical cancer treatment using antibody-platinum(IV)prodrugs conjugates.

Optimization of the Process for Preparing Bivalent Polysaccharide Conjugates to Develop Multivalent Conjugate Vaccines against Streptococcus pneumoniae or Neisseria meningitidis and Comparison with the Corresponding Licensed Vaccines in Animal Models

Objective:This study aimed to describe,optimize and evaluate a method for preparing multivalent conjugate vaccines by simultaneous conjugation of two different bacterial capsular polysaccharides(CPs)with tetanus toxoid(TT)as bivalent conjugates.Methods:Different molecular weights(MWs)of polysaccharides,activating agents and capsular polysaccharide/protein(CP/Pro)ratio that may influence conjugation and immunogenicity were investigated and optimized to prepare the bivalent conjugate bulk.Using the described method and optimized parameters,a 20-valent pneumococcal conjugate vaccine and a bivalent meningococcal vaccine were developed and their effectiveness was compared to that of corresponding licensed vaccines in rabbit or mouse models.Results:The immunogenicity test revealed that polysaccharides with lower MWs were better for Pn1-TT-Pn3 and MenA-TT-MenC,while higher MWs were superior for Pn4-TT-Pn14,Pn6A-TT-Pn6B,Pn7F-TT-Pn23F and Pn8-TT-Pn11A.For activating polysaccharides,1-cyano-4-dimethylaminopyridinium tetrafluoroborate(CDAP)was superior to cyanogen bromide(CNBr),but for Pn1,Pn3 and MenC,N-(3-dimethylaminopropyl)-N’-ethylcarbodiimide hydrochloride(EDAC)was the most suitable option.For Pn6A-TT-Pn6B and Pn8-TT-Pn11A,rabbits immunized with bivalent conjugates with lower CP/Pro ratios showed significantly stronger CP-specific antibody responses,while for Pn4-TT-Pn14,higher CP/Pro ratio was better.Instead of interfering with the respective immunological activity,our bivalent conjugates usually induced higher IgG titers than their monovalent counterparts.Conclusion:The result indicated that the described conjugation technique was feasible and efficacious to prepare glycoconjugate vaccines,laying a solid foundation for developing extended-valent multivalent or combined conjugate vaccines without potentially decreased immune function.

The ABC of ADCs (Antibody-Drug Conjugates): A Comprehensive Review of Technical, Regulatory, and Clinical Challenges

Over the past several decades, there has been a significant surge in the development of Antibody-Drug Conjugates (ADCs). Designing an ideal ADC presents a multifaceted challenge, requiring the precise orchestration of various elements such as antigens, antibodies, linkers, and payloads. While ADCs aim to target tumor cells specifically, several antigens can also be found in regular tissues, potentially compromising the specificity of ADCs in therapeutic applications. The complexity extends to antibody selection, necessitating effective targeting of the desired antigen and ensuring compatibility with linkers for effective payload delivery. Additionally, the linker and payload combination are critical for the ADC’s therapeutic efficiency, balancing stability in circulation and timely payload release upon target binding. ADC doses must be safe for normal tissues while ensuring the released payloads are effective. The success of ADCs is attributed to their unmatched efficacy compared to traditional chemotherapy agents. The current research article aims to provide a technical review of Antibody-Drug Conjugates (ADCs) for cancer therapies. A brief discussion on the basics of ADCs, regulatory approach, overview, and technical complexities for quantification is presented. This review also summarizes recently approved ADCs and introduces the concepts of antibodies, linkers, and payloads. The article also outlines cancer-specific ADCs currently in late-stage clinical trials for cancer treatment.

Recent advances and innovations in the design and fabrication of wearable flexible biosensors and human health monitoring systems based on conjugated polymers

Wearable biosensors have received great interest as patient-friendly diagnostic technologies because of their high flexibility and conformability.The growing research and utilization of novel materials in designing wearable biosensors have accelerated the development of point-of-care sensing platforms and implantable biomedical devices in human health care.Among numerous potential materials,conjugated polymers(CPs)are emerging as ideal choices for constructing high-performance wearable biosensors because of their outstanding conductive and mechanical properties.Recently,CPs have been extensively incorporated into various wearable biosensors to monitor a range of target biomolecules.However,fabricating highly reliable CP-based wearable biosensors for practical applications remains a significant challenge,necessitating novel developmental strategies for enhancing the viability of such biosensors.Accordingly,this review aims to provide consolidated scientific evidence by summarizing and evaluating recent studies focused on designing and fabricating CP-based wearable biosensors,thereby facilitating future research.Emphasizing the superior properties and benefits of CPs,this review aims to clarify their potential applicability within this field.Furthermore,the fundamentals and main components of CP-based wearable biosensors and their sensing mechanisms are discussed in detail.The recent advancements in CP nanostructures and hybridizations for improved sensing performance,along with recent innovations in next-generation wearable biosensors are highlighted.CPbased wearable biosensors have been—and will continue to be—an ideal platform for developing effective and user-friendly diagnostic technologies for human health monitoring.

Antibody-Drug Conjugates (ADCs): Navigating Four Pillars of Safety, Development, Supply Chain and Manufacturing Excellence

Antibody-drug conjugates (ADCs) are pioneering biologics that merge antibodies’ specificity with small molecules’ potency. With a handful of FDA-approved ADCs in the market and many under development, ADCs are poised to revolutionize therapeutics. This paper examines the complexities of ADC production, emphasizing the importance of process characterization and the pivotal role of supply chain characteristics, safety requirements, and Contract Manufacturing Organizations (CMOs) with proficiency. The swift transition of antibody-drug conjugate (ADC) programs from early to advanced clinical stages underscores the urgency for quick and efficient commercial launch preparation. This article delves into strategies to hasten commercial readiness, supply chain strategy, the significance of partnering with adept contract development and manufacturing organizations (CDMOs), and the challenges of ADC production.

Discovering metabolic vulnerability using spatially resolved metabolomics for antitumor small molecule-drug conjugates development as a precise cancer therapy strategy

Against tumor-dependent metabolic vulnerability is an attractive strategy for tumor-targeted therapy.However,metabolic inhibitors are limited by the drug resistance of cancerous cells due to their metabolic plasticity and heterogeneity.Herein,choline metabolism was discovered by spatially resolved metabolomics analysis as metabolic vulnerability which is highly active in different cancer types,and a choline-modified strategy for small molecule-drug conjugates(SMDCs)design was developed to fool tumor cells into indiscriminately taking in choline-modified chemotherapy drugs for targeted cancer therapy,instead of directly inhibiting choline metabolism.As a proof-of-concept,choline-modified SMDCs were designed,screened,and investigated for their druggability in vitro and in vivo.This strategy improved tumor targeting,preserved tumor inhibition and reduced toxicity of paclitaxel,through targeted drug delivery to tumor by highly expressed choline transporters,and site-specific release by carboxylesterase.This study expands the strategy of targeting metabolic vulnerability and provides new ideas of developing SMDCs for precise cancer therapy.

Effect of electron-electron interaction on polarization process of exciton and biexciton in conjugated polymer

By using one-dimensional tight-binding model modified to include electron-electric field interaction and electron-electron interaction,we theoretically explore the polarization process of exciton and biexciton in cis-polyacetylene.The dynamical simulation is performed by adopting the non-adiabatic evolution approach.The results show that under the effect of moderate electric field,when the strength of electron-electron interaction is weak,the singlet exciton is stable but its polarization presents obvious oscillation.With the enhancement of interaction,it is dissociated into polaron pairs,the spin-flip of which can be observed through modulating the interaction strength.For the triplet exciton,the strong electron-electron interaction restrains its normal polarization,but it is still stable.In the case of biexciton,the strong electron-electron interaction not only dissociate it,but also flip its charge distribution.The yield of the possible states formed after the dissociation of exciton and biexciton is also calculated.

A Stable Open-Shell Conjugated Diradical Polymer with Ultra-High Photothermal Conversion Efficiency for NIR-Ⅱ Photo-Immunotherapy of Metastatic Tumor

Massive efforts have been concentrated on the advance of eminent near-infrared(NIR) photothermal materials(PTMs) in the NIR-Ⅱ window(1000–1700 nm), especially organic PTMs because of their intrinsic biological safety compared with inorganic PTMs. However, so far, only a few NIR-Ⅱresponsive organic PTMs was explored, and their photothermal conversion efficiencies(PCEs) still remain relatively low. Herein, donor–acceptor conjugated diradical polymers with open-shell characteristics are explored for synergistically photothermal immunotherapy of metastatic tumors in the NIR-Ⅱ window. By employing side-chain regulation, the conjugated diradical polymer TTB-2 with obvious NIR-Ⅱ absorption was developed, and its nanoparticles realize a record-breaking PCE of 87.7% upon NIR-Ⅱ light illustration. In vitro and in vivo experiments demonstrate that TTB-2 nanoparticles show good tumor photoablation with navigation of photoacoustic imaging in the NIR-Ⅱ window, without any side-effect. Moreover, by combining with PD-1 antibody,the pulmonary metastasis of breast cancer is high-effectively prevented by the efficient photo-immunity effect. Thus, this study explores superior PTMs for cancer metastasis theranostics in the NIR-Ⅱ window, offering a new horizon in developing radical-characteristic NIR-Ⅱ photothermal materials.

Co and postseismic fault slip models of the 2022 M_(W)6.7 Menyuan earthquake reveal conjugated faulting tectonics at the central section of the Lenglongling fault

The 2022 M_(W)6.7 Menyuan earthquake ruptured the western end of the Tianzhu seismic gap,providing an opportunity to study the regional seismogenic characteristics and seismic hazards.Here we use interferometric synthetic aperture radar(InSAR)and seismic data to study the mainshock rupture,early afterslip and the second largest aftershock of the 2022 Menyuan earthquake sequences.Our modeling results show that the mainshock ruptured the Lenglongling fault and the Tuolaishan fault with a maximum slip of~3 m.Rapid postseismic transient deformation occurred at the center of the Lenglongling fault.Our afterslip modeling reveals that the majority of afterslip occurred in the deeper part of the Lenglongling fault.A high-angle conjugated faulting event is found at the middle section of the Lenglongling fault.We use the stress inversion to investigate the possible triggering mechanism of the conjugated rupture event.The results indicate the maximum principal stress direction is in~222°,forming a~22°angle between the conjugated fault of second largest aftershock and the mainshock.The calculated normal stress changes indicate the region is within a pull-apart stress field,which favors such a conjugated rupturing event.Our study will help understand the rupture behavior of such kind of conjugated fault in other regions.

5-year vaccine protection following a single dose of Vi-tetanus toxoid conjugate vaccine in Bangladeshi children(TyVOID):a cluster randomised trial

Background:WHO currently recommends a single dose of typhoid conjugate vaccine(TCV)in high-burden countries based on 2-year vaccine efficacy data from large randomised controlled trials.Given the decay of immunogenicity,the protection beyond 2 years is unknown.We therefore extended the follow-up of the TyVAC trial in Bangladesh to assess waning of vaccine protection to 5 years after vaccination.

Effect of Liposome Double-Coated with Chitosan and Chitosan-EDTA Conjugates on Oral Absorption of Insulin

Aim To evaluate the gastrointestinal uptake of the insulin liposomes double-coated with chitosan （Ch） and chitosan-EDTA conjugates （CEC）, and verify their efficiencies. Methods Insulin-liposomes were prepared by reversed-phase evaporation. The hypoglycemic effects of the insulin liposomes coated with Ch or/and CEC were investigated using the glucose oxidase method after oral administration in diabetic rats, normal rats, and beagle dogs. Serum insulin concentrations in beagle dogs were determined by radioimmunoassay and were assessed by Pkanalyst computer program. Results The animals fed the insulin liposomes coated with Ch or/and CEC were able to regulate better the glucose load than the animals receiving PBS or uncoated insulin liposome, and the regulative effects of the insulin liposomes double-coated with Ch and CEC were better than those of the insulin liposomes coated with Ch or CEC alone. After oral administration of the insulin-liposomes double-coated with Ch and CEC to animals, a significant （P 〈 0. 05 ） blood glucose reduction was observed. Their relative pharmacological bioavailability was higher than 9 % in comparison with subcutaneous injection of insulin. In addition, in comparison with subcutaneous injection of insulin, the relative bioavailability was 12. 67 % calculated by area under the curve of serum insulin concentration versus time profile after oral administration of the insulin-liposomes double-coated with Ch and CEC to beagle dogs. Conclusion The insulin-liposomes double-coated with Ch and CEC were conducive to improving oral bioavailability of insulin.

CT- B Conjugates顺行示踪显色α-晶状体蛋白对损伤后视神经纤维保护作用的实验研究

目的观察α-晶状体蛋白对损伤后视神经纤维的保护作用。方法将成年Long evens大鼠26只,其中10只用于提取α-晶状体蛋白,另外16只分成4组,分别为正常对照组和伤后2,4,6周组,每组4只。损伤神经后分别右眼经玻璃体腔注射浓度为1×10-5g/L的α-晶体蛋白5μl,左眼牛血清白蛋白5μl,分别于伤后2,4,6周进行视神经取材。取材前48h,在每只眼玻璃体腔中注射CT-B(霍乱毒素B亚单位)Conjugates2.5μl,取材固定脱水并行冰冻切片后进行激光共聚焦照相(488nm波长光)观察。结果CTB Conjugates标记的夹伤视神经中可见线状条索神经纤维染色,并呈现一定扭曲,夹杂点状或者小团块状染色。α-晶状体蛋白组的荧光强度显著高于牛血清白蛋白组。结论CTB Conjugates顺染视神经示踪技术是观察和研究损伤后视神经病理变化的有效和简便的方法,α-晶状体蛋白对损伤后的视神经纤维具有保护作用。

Characterization and in vitro release studies of oral microbeads containing thiolated pectin–doxorubicin conjugates for colorectal cancer treatment

Novel oral microbeads were developed based on a biopolymer–drug conjugate of doxorubicin(DOX) conjugated with thiolated pectin via reducible disulfide bonds. The microbeads were fabricated by ionotropic gelation with cations such as Al3+, Ca2+ and Zn2+. The results showed that using zinc acetate can produce the strongest microbeads with spherical shape.However, the microbeads prepared from thiolated pectin–DOX conjugate were very soft and irregular in shape. To produce more spherical microbeads with suitable strength, the native pectin was then added to the formulations. The particle size of the microbeads ranged from 0.87 to 1.14 mm. The morphology of the microbeads was characterized by optical and scanning electron microscopy. DOX was still in crystalline form when used in preparing the microbeads, as confirmed by powder X-ray diffractometry. Drug release profiles showed that the microbeads containing thiolated pectin–DOX conjugate exhibited reduction-responsive character;in reducing environments, the thiolated pectin–DOX conjugate could uncouple resulting from a cleavage of the disulfide linkers and consequently release the DOX. The best-fit release kinetics of the microbeads containing thiolated pectin–DOX conjugate, in the medium without reducing agent, fit the Korsmeyer–Peppas model while those in the medium with reducing agent fit a zero-order release model. These results suggested that the microbeads containing thiolated pectin–DOX conjugate may be a promising platform for cancer-targeted delivery of DOX, exploiting the reducing environment typically found in tumors.

Characterization of Hapten-Protein Conjugates for Immunoassay of Polycyclic Aromatic Hydrocarbons(PAHs)

Preparation and characterization of the hapten-protein conjugates are fundamental to developing environmental immunoassays. As a hapten, 1-pyrenebutyric acid（PBA） was conjugated to the carrier protein of bovine serum albumin（BSA） or ovalbumin（OVA） by active ester method. Infrared spectra（IR） showed that PBA-BSA and PBA-OVA conjugates were successfully prepared. The number of the haptens conjugated to the carrier protein was determined by ultraviolet spectra（UV） and matrix-assisted laser desorption ionization time-of-flight mass spectrometry（MALDI-TOF-MS）. The calculated average binding ratios of PBA/BSA and PBA/OVA were 18：1 and 10：1 by UV, and 31：1 and 22：1 by MALDI-TOF-MS, respectively. Although there was a discrepancy between the results determined by the two methods, both of them were useful for the characterization of the hapten-protein conjugates. The antibody was produced against the antigen of PBA-BSA, and the affinity was tested by the double agar diffusion method The conjugates and the antibody could be used for developing a sensitive and selective immunoassay of polycyclic aromatic hydrocarbons（PAHs）.

Synthesis and characterization of HPMA copolymer-5-FU conjugates

N-（2-Hydroxypropyl） methacrylamide copolymer-5-fluorouracil （PHPMA-FU） conjugates were synthesized by a novel and simplified synthetic route, and characterized by UV, FTIR and HPLC analyses. The conjugated content of 5-fluorouracil （5-FU） was 3.41 ± 0.07 wt%. The stabilities of PHPMA-FU conjugates under different conditions were studied. The results showed that HPMA copolymer was a potential carrier for tumor-targeting delivery of 5-FU.

QSAR Studies on the Inhibitory Activityof Levofloxacin-thiadiazole HDACi Conjugates to Histone Deacetylases

A molecular electronegativity distance vector(M)based on 13 atomic types has been used to describe the structures of 19 conjugates(LHCc)of levofloxacin-thiadiazole HDAC inhibitor(HDACi)and related inhibitory activities(pH,i=1,2,6)of LHCc against histone deacetylases(HDACs,such as HDAC1,HDAC2 and HDAC6).The quantitative structure-activity relationships(QSAR)were established by using leaps-and-bounds regression analysis for the inhibitory activities(pH)of 19 above compounds to HDAC1,HDAC2 and HDAC6 along with M.The correlation coefficients(R~2)and the leave-one-out(LOO)cross validation Rfor the pH,pHand pHmodels were 0.976 and 0.949;0.985 and 0.977;0.976 and 0.932,respectively.The QSAR models had favorable correlations,as well as robustness and good prediction capability by R~2,F,R~2,A,Fand Vtests.Validated by using 3876 training sets,the models have good external prediction ability.The results indicate that the molecular structural units:–CH–(g=1,2),–NH,–OH,=O,–O–and–S–are the main factors which can affect the inhibitory activity of pH,pHas well as pHbioactivities of these compounds directly.Accordingly,the main interactions between HDACs inhibitor and HDACs are hydrophobic interaction,hydrogen bond,and coordination with Znto form compounds,which is consistent with the results in reports.

FITC labeling of human insulin and transport of FITC-insulin conjugates through MDCK cell monolayer

Fluorescein isothiocyanate-labeled insulin(FITC-insulin)has been widely used for bioanalytical applications.Due to the high cost of commercial FITC-insulin and tedious labeling procedures described in the literature,there is still a need to develop a cost effective,reliable and quick labeling method for insulin.The purpose of the present work was to develop a quick and affordable method for FITC labeling of human insulin and to determine the effect of different conjugations of FITC to human insulin on its permeability through the MDCK cell monolayer.FITC labeling of insulin gives mono-,di-or tri-conjugates depending on the reaction time and the molar ratio of FITC:insulin.Mono-conjugate with unlabeled insulin,mixture of di-and tri-conjugate,and tri-conjugate with very little amount of di-conjugate were synthesized in less than 4 h.Degree of conjugation had an effect on the permeability of insulin through the MDCK cell monolayer.Mono-conjugate had higher permeability than the unlabeled insulin due to increase in partition coefficient.However,tri-conjugate showed lower permeability than the unlabeled insulin due to the increase in molecular weight.

The synthesis and molecular recognization of the polyamine transporter of hydrazine-modified diamine conjugates

A series of four novel hydrazine-modified diamine conjugates （7a-b, 8a-b） were synthesized and evaluated for cytotoxicity against Melanoma B 16, α-difluoromethylornithine （DFMO）-treated B 16, spermidine （SPD）-treated B 16, Mouse leukemia L 1210 and Hela cell lines. Both the DFMO-B 16 and SPD-B 16 experiments indicated that conjugates 7a-b and 8a-b could recognize the polyamine transporter （PAT） and enter the cells in part or in whole via PAT, although they were not as efficient as the reference, 9- anthracenemethyl homospermidine （1）. 2007 Chao Jie Wang. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.

Synthesis of novel fullereneα-amino acid conjugates

Aspartic acid and glutamic acid with protected α-amino and α-carboxyl groups had been used to react with the activated hydroxyl group of N-substituted 3,4-fullero pyrrolidine. The products were deprotected, affording two monofuUerene α-amino acids, monofullerene aspartic acid （mFas） and monofullerene glutamic acid （mFgu）. Then a bifullerene glutamic acid conjugate （bFguC） was synthesized by reaction of mFgu containing protected amino group with N-substituted 3,4-fullero pyrrolidine.