Presence Of Cathepsin Research Articles

Biosynthesis of multifunctional transformable peptides for downregulation of PD-L1.

Here, we present a biosynthesized material M1 for immune checkpoint blocking therapy. M1 could realize a morphological transformation from globular to fibrous in situ in the presence of cathepsin B (CtsB) after entering tumor cells. The GO203 peptides of M1 are exposed, which could bind to mucin 1 (MUC1) to suppress the homodimerization process of MUC1, thereby downregulating PD-L1 expression.

Noise exposure increase apoptosis in the hippocampus of AD mice through the upregulation of CTSS

In recent years, it has become an acknowledged fact that noise exposure can lead to cognitive impairments, and researchers have shown increasing interest in this area. However, the detrimental impact of noise exposure on Alzheimer's disease (AD) animal models might be considerably greater than on ordinary model mice, yet the mechanisms by which noise exposure affects the hippocampus in these models have been scarcely investigated. This study we used 4D Label-free proteomics to identify distinctive differentially expressed proteins in the hippocampus of AD model mice following noise exposure. Among these proteins, the presence of Cathepsin S(CTSS) cannot be disregarded. Utilizing experimental techniques such as Western blot, immunofluorescence, and rt-qPCR, we confirmed the expression of CTSS in the hippocampus of APP/PS1 mice after noise exposure. Additionally, we examined downstream molecules including P53,BCL-2, BAX, and CASPASE3 using KEGG pathway analysis. The results indicated an elevation in CTSS expression, a reduction in the anti-apoptotic gene BCL-2, and an increase in the expression of BAX and cleaved CASPASE3. Based on these findings, we hypothesize that noise exposure potentially heightens apoptosis within the hippocampus through upregulating CTSS expression, subsequently posing a threat to AD model animals.

Biosynthesis of Multifunctional Transformable Peptides for Inducing Tumor Cell Apoptosis.

Engineered nanomaterials hold great promise to improve the specificity of disease treatment. Herein, a fully protein-based material is obtained from nonpathogenic Escherichia coli (E. coli), which is capable of morphological transformation from globular to fibrous in situ for inducing tumor cell apoptosis. The protein-based material P1 is comprised of a β-sheet-forming peptide KLVFF, pro-apoptotic protein BAK, and GFP along with targeting moieties. The self-assembled nanoparticles of P1 transform into nanofibers in situ in the presence of cathepsin B, and the generated nanofibrils favor the dimerization of functional BH3 domain of BAK on the mitochondrial outer membrane, leading to efficient anticancer activity both in vitro and in vivo via mitochondria-dependent apoptosis through Bcl-2 pathway. To precisely manipulate the morphological transformation of biosynthetic molecules in living cells, a spatiotemporally controllable anticancer system is constructed by coating P1-expressing E. coli with cationic conjugated polyelectrolytes to release the peptides in situ under light irradiation. The biosynthetic peptide-based enzyme-catalytic transformation strategy in vivo would offer a novel perspective for targeted delivery and shows great potential in precision disease therapeutics.

Glaucomatous aqueous humor vesicles are smaller and differ in composition compared to controls

Cells communicate with each other using vesicles of varying sizes, including a specific repertoire known as exosomes. We isolated aqueous humor (AH)-derived vesicles using two different methods: ultracentrifugation and an exosome isolation kit. We confirmed a unique vesicle size distribution in the AH derived from control and primary open-angle glaucoma (POAG) patients using various techniques, including Nanotracker, dynamic light scattering, atomic force imaging, and electron microscopy. Bonafide vesicle and/or exosome markers were present by dot blot in both control and POAG AH-derived vesicles. Marker levels differed between POAG and control samples, while non-vesicle negative markers were absent in both. Quantitative labeled (iTRAQ) proteomics showed a reduced presence of a specific protein, STT3B, in POAG compared to controls, which was further confirmed using dot blot, Western blot, and ELISA assays. Along the lines of previous findings with AH profiles, we found vast differences in the total phospholipid composition of AH vesicles in POAG compared to controls. Electron microscopy further showed that the addition of mixed phospholipids alters the average size of vesicles in POAG. We found that the cumulative particle size of type I collagen decreased in the presence of Cathepsin D, which normal AH vesicles were able to protect against, but POAG AH vesicles did not. AH alone had no effect on collagen particles. We observed a protective effect on collagen particles with an increase in artificial vesicle sizes, consistent with the protective effects observed with larger control AH vesicles but not with the smaller-sized POAG AH vesicles. Our experiments suggest that AH vesicles in the control group provide greater protection for collagen beams compared to POAG, and their increased vesicle sizes are likely contributing factors to this protection.

A cystatin C similar protein from Musa acuminata that inhibits cathepsin B involved in rheumatoid arthritis using in silico approach and in vitro cathepsin B inhibition by protein extract

Rheumatoid arthritis (RA) is an auto-immune disease that affects the synovial lining of the joints, causes synovitis and culminates to joint destruction. Cathepsin B is responsible for digesting unwanted proteins in extracellular matrix but its hyper expression could implicate in pathological diseases like RA. Available treatments for RA are classified into non-steroidal anti-inflammatory drugs (NSAIDs), disease-modifying anti-rheumatic drugs (DMARDs), and steroids, but the severe side effects associated with these drugs is one of concerns and cannot be ignored. Thus, any alternative therapy with minimum or no side effects would be a cornerstone. In our in silico studies a cystatin C similar protein (CCSP) has been identified from Musa acuminata that could effectively inhibit the cathepsin B activity. In silico and molecular dynamics studies showed that the identified CCSP and cathepsin B complex has binding energy −66.89 kcal/mol as compared to cystatin C - cathepsin B complex with binding energy of −23.38 kcal/mol. These results indicate that CCSP from Musa acuminata has better affinity towards cathepsin B as compared to its natural inhibitor cystatin C. Hence, CCSP may be suggested as an alternative therapeutic in combating RA by inhibiting its one of the key proteases cathepsin B. Further, in vitro experiments with fractionated protein extracts from Musa sp. peel inhibited cathepsin B to 98.30% at 300 µg protein concentration and its IC50 was found to be 45.92 µg indicating the presence of cathepsin B inhibitor(s) in protein extract of peel which was further confirmed by reverse zymography. Communicated by Ramaswamy H. Sarma

Two-Wave Variable Nanotheranostic Agents for Dual-Mode Imaging-Guided Photo-Induced Triple-Therapy for Cancer.

Photothermal therapy (PTT) is a promising strategy for cancer treatment, but its clinical application relies heavily on accurate tumor positioning and effective combination. Nanotheranostics has shown superior application in precise tumor positioning and treatment, bringing potential opportunities for developing novel PTT‐based therapies. Here, a nanotheranostic agent is proposed to enhance magnetic resonance imaging (MRI)/ near‐infrared fluorescence imaging (NIRFI) imaging‐guided photo‐induced triple‐therapy for cancer. Thermosensitive liposomes co‐loaded with SPIONs/IR780 and Abemaciclib (SIA‐TSLs), peptide ACKFRGD, and click group 2‐cyano‐6‐amino‐benzothiazole (CABT) are co‐modified on the surface of SIA‐TSLs to form SIA‐αTSLs. ACKFRGD can be hydrolyzed to expose the 1, 2‐thiolamino groups in the presence of cathepsin B in tumors, which click cycloaddition with the cyano group on CABT, resulting in the formation of SIA‐αTSLs aggregates. The aggregation of SIA‐αTSLs in tumors enhances the MRI/NIRFI imaging capability and enables precise PTT. Photo‐induced triple‐therapy enhances precision cancer therapy. First, PTT ablates specific tumors and induces ICD via localized photothermal. Second, local tumor heating promotes the rupture of SIA‐αTSLs, which release Abemaciclib to block the tumor cell cycle and inhibit Tregs proliferation. Third, injecting GM‐CSF into tumor tissue leads to recruitment of dendritic cells and initiation of antitumor immunity. Collectively, these results present a promising nanotheranostic strategy for future cancer therapy.

Co-exposure of chronic stress and alumina nanoparticles aggravates hippocampal microglia pyroptosis by activating cathepsin B/NLRP3 signaling pathway

Combined exposure of chronic stress and alumina nanoparticles (AlNPs) aggravates hippocampal injury, but the pathogenesis is unevaluated. This study aimed to investigate the effect and mechanism of co-exposure to chronic stress and AlNPs on hippocampal microglia pyroptosis. In this study, chronic restraint stress (CRS) alone caused NLRP3-mediated hippocampal microglia pyroptosis, but AlNPs did not. Moreover, co-exposure to CRS and AlNPs exacerbated hippocampal microglia pyroptosis, resulting in more severe hippocampal damage and behavioral deficits in rats. Protein-protein interaction network predicted that cathepsin B was a potential regulatory protein of NLRP3. CRS up-regulated cathepsin B expression which had a more pronounced increase in co-exposure group. Whereas, caspase-1 inhibitor VX-765 alleviated hippocampal microglia pyroptosis and behavioral deficits in rats. Consistent with in vivo results, co-exposure of corticosterone and AlNPs aggravated NLRP3-mediated pyroptosis and cathepsin B expression in HAPI cells. Nevertheless, the pyroptosis of HAPI cells was inhibited by cathepsin B inhibitor CA-074Me and NLRP3 knockout, respectively. NLRP3 agonist nigericin failed to promote the pyroptosis of HAPI cells in the presence of cathepsin B inhibition. These results demonstrated that co-exposure to chronic stress and AlNPs could aggravate hippocampal microglia pyroptosis by activating cathepsin B/NLRP3 signaling pathway, resulting in hippocampal damage and behavioral deficits.

Deep Downregulation of PD-L1 by Caged Peptide-Conjugated AIEgen/miR-140 Nanoparticles for Enhanced Immunotherapy.

Downregulating programmed cell death ligand 1(PD-L1) protein levels in tumor cells is an effective way to achieve immune system activation for oncology treatment, but current strategies are inadequate. Here, we design a caged peptide-AIEgen probe (GCP) to self-assemble with miR-140 forming GCP/miR-140 nanoparticles. After entering tumor cells, GCP/miR-140 disassembles in the presence of Cathepsin B (CB) and releases caged GO203 peptide, miR-140 and PyTPA. Peptide decages in the highly reductive intracellular environment and binds to mucin 1 (MUC1), thereby downregulating the expression of PD-L1. Meanwhile, miR-140 reduces PD-L1 expression by targeting downregulation of PD-L1 mRNA. Under the action of PyTPA-mediated photodynamic therapy (PDT), tumor-associated antigens are released, triggering immune cell attack on tumor cells. This multiple mechanism-based strategy of deeply downregulating PD-L1 in tumor cells activates the immune system and thus achieves effective immunotherapy.

Deep Downregulation of PD‐L1 by Caged Peptide‐Conjugated AIEgen/miR‐140 Nanoparticles for Enhanced Immunotherapy

AbstractDownregulating programmed cell death ligand 1(PD‐L1) protein levels in tumor cells is an effective way to achieve immune system activation for oncology treatment, but current strategies are inadequate. Here, we design a caged peptide‐AIEgen probe (GCP) to self‐assemble with miR‐140 forming GCP/miR‐140 nanoparticles. After entering tumor cells, GCP/miR‐140 disassembles in the presence of Cathepsin B (CB) and releases caged GO203 peptide, miR‐140 and PyTPA. Peptide decages in the highly reductive intracellular environment and binds to mucin 1 (MUC1), thereby downregulating the expression of PD‐L1. Meanwhile, miR‐140 reduces PD‐L1 expression by targeting downregulation of PD‐L1 mRNA. Under the action of PyTPA‐mediated photodynamic therapy (PDT), tumor‐associated antigens are released, triggering immune cell attack on tumor cells. This multiple mechanism‐based strategy of deeply downregulating PD‐L1 in tumor cells activates the immune system and thus achieves effective immunotherapy.

Effect of Lysosomal Cathepsin L on Proteolysis of Beef Myofibrillar Proteins In Vivo and In Vitro.

This study investigated the effects of cathepsin L on proteolysis of beef myofibrillar proteins in vivo and in vitro. Results indicated that cathepsin L affected the degradation of desmin and troponin-T during postmortem aging, and the extent of degradation increased from 1 d to 14 d postmortem. No detectable degradation of titin, nebulin, and α-actinin in the presence of cathepsin L inhibitor was observed during postmortem aging. In vitro, cathepsin L affected the degradation of titin, nebulin, and troponin-T, and the extent of degradation increased with increasing incubation time. Nevertheless, cathepsin L did not cause the degradation of α-actinin and desmin, regardless of incubation temperature. The different results between in vitro and in vivo experiments might mainly depend on different treatment temperatures. Overall, these results indicated that cathepsin L participated in the degradation of myofibrillar proteins and meat tenderization.

In vitro determination of the immunosuppressive effect, internalization, and release mechanism of squalene-gusperimus nanoparticles for managing inflammatory responses

Gusperimus is an anti-inflammatory drug that has shown to be effective in managing autoimmunity and preventing graft rejection. This is unstable and easily broken down into cytotoxic components. We encapsulated gusperimus binding it covalently to squalene obtaining squalene-gusperimus nanoparticles (Sq-GusNPs). These nanoparticles enhanced the immunosuppressive effect of gusperimus in both mouse macrophages and T cells. The half-maximal inhibitory concentration in macrophages was 9-fold lower for Sq-GusNPs compared with the free drug. The anti-inflammatory effect of the Sq-GusNPs was maintained over time without cytotoxicity. By studying nanoparticles uptake by cells with flow cytometry, we demonstrated that Sq-GusNPs are endocytosed by macrophages after binding to low-density lipoprotein receptors (LDLR). In presence of cathepsin B or D release of gusperimus is increased demonstrating the participation of proteases in the release process. Our approach may allow the application of Sq-GusNPs for effective management of inflammatory disorders including autoimmunity and graft rejection.

A bifunctional molecule-based strategy for the development of theranostic antibody-drug conjugate.

Antibody-drug conjugates (ADCs) are being developed worldwide with the potential to revolutionize current cancer treatment strategies. Developing novel theranostic ADCs with therapeutic utility and imaging capability is an attractive and challenging subject that promises advances in the field of personalized medicine. In this work, we propose a bifunctional molecule-based strategy for the development of theranostic ADCs.Methods: We developed a theranostic ADC consisting of the anti-Her2 antibody Mil40, monomethyl auristatin E (MMAE) as the active payload, and a 7-amino-3-hydroxyethyl-coumarin (7-AHC)-based dipeptide linker, which functions as a novel bifunctional fluorescence probe that allows self-elimination cleavage in the presence of cathepsin B for payload release and fluorophore activation. The on-off fluorescence properties and the antitumor effect in vitro and in vivo were investigated.Results: A 48-fold fluorescence enhancement was observed within 1 h when the 7-AHC-based linker was exposed to cathepsin B. Cleavage upon exposure to cathepsin B allows MMAE and fluorophore intracellular release and the monitoring of MMAE distribution using confocal microscopy. Additionally, the newly developed ADC retains the advantages of traditional p-aminobenzyloxycarbonyl-containing ADCs, such as good stability (t1/2 > 7 days) and high activity in vitro (IC50 = 0.09-3.74 nM). Importantly, the theranostic ADC exhibited the equivalent antitumor efficacy to the marketed ADC T-DM1 in the classic breast cancer model.Conclusion: We suggest that the present strategy can be universally applied in all p-aminobenzyloxycarbonyl-containing ADCs. Overall, theranostic ADCs may play a role in developing new theranostic systems and promoting personalized medicine research.

Magnetic nanoparticle decorated anodic alumina nanotubes for fluorescent detection of cathepsin B

In this work, we present the process to provide anodic alumina nanotubes with magnetic responsivity based on magnetic nanoparticles. We demonstrate the possibility to cause the motion of these composite nanotubes under magnetic field, providing them with guided mobility. The obtained magnetic anodic alumina nanotubes are completely characterized and their potential to undergo selective and effective functionalization, and stimuli-responsive load release is demonstrated. For this purpose, protease-triggered release of fluorescent molecules loaded inside the magnetic anodic alumina nanotubes (MAANTs) by selective functionalization is performed. The inner walls of the MAANTs were selectively covered with protein padding of albumin-fluorescein isothiocyanate conjugate (FITC-BSA) through means of silanization. Protein functionalization was designed to undergo proteolytic hydrolysis in presence of cathepsin B- protease highly expressed during growth and initial stages of tumor metastasis – in order to cleave peptide bond of albumin and release fluorescent fragments of the protein. Proteolytic reaction with the enzyme is performed under acidic conditions. Presented arrangement is an exemplary combination of functionalities – which are vast – and of value for applications like drug delivery and biosensing applications.

Peptide‐Capped Mesoporous Nanoparticles: Toward a more Efficient Internalization of Alendronate

AbstractOsteoporosis is an illness which appears when the osteoblast/osteoclast activities are unbalanced taking place bone resorption (caused by osteoclasts) in higher extension than bone formation (induced by osteoblasts). Alendronate is one of the most used drugs for osteoporosis treatment despite its scarce bioavailability. Here we present the synthesis and characterization of mesoporous gated nanoparticles (two sets) for the controlled release of alendronate. The first set of nanoparticles (S1) were loaded with sulforhodamine B and capped with a peptide that could be selectively hydrolyzed by cathepsin K enzyme (overexpressed in osteoclasts). The second set (S2) was functionalized with aminopropyl moieties, loaded with nitrobenzofurazan labelled alendronate and capped with the same peptide. Both nanoparticles were internalized by RAW 264.7 macrophages (which could differentiate in osteoclasts) and were able to release its entrapped cargo in the presence of cathepsin K added in the macrophage lysates. Using S2 nanoparticles 4.2% of the total alendronate amount in contact with the cells is liberated inside them and could produce its therapeutic effect.

Detection and imaging of cathepsin L in cancer cells using the aggregation of conjugated polymer dots and magnetic nanoparticles

New technique for cathepsin L detection and imaging was developed via controlling an aggregation between magnetic nanoparticles (MNPs) and conjugated polymer dots (CPdots). By changing the electrostatic surface charges of MNPs, the techniques provided two protocols: 1) fluorescence quenching and spin-spin relaxation (T2)-based magnetic resonance imaging (MRI); 2) fluorescence recovery for fluorescent imaging. By adding cathepsin L, the fluorescence and MRI relaxivity were altered by the formation of aggregates of CPdots and MNPs, inducing fluorescence quenching by MNP as well as a change in T2 relaxation. In addition, nonfluorescent, pre-aggregated nanohybrid (CPdots and MNPs) can be dissolved in the presence of cathepsin L, resulting in turn-on fluorescent detection and the imaging of cathepsin L in cancer cells and in mice with tumors. In all cases, the MNPs played important roles as the fluorescence quencher and as the MRI-signal generator. The surface of CPdots was covered with poly(L-lysine) (pLys) for the aggregation of CPdots and MNPs, in which pLys was specifically degraded by the enzymatic action of cathepsin L. The CPdots systems showed high sensitivity and selectivity toward cathepsin L, by which these systems can be considered as potential candidates for cathepsin L detection and imaging.

Artemisinin-Based Smart Nanomedicines with Self-Supply of Ferrous Ion to Enhance Oxidative Stress for Specific and Efficient Cancer Treatment.

Though abundant researches report that artemisinin could inhibit cancer cell growth via generating toxic reactive oxygen species (ROS), the therapeutic efficiency of artemisinin for cancer treatment is still limited owing to the insufficient intracellular ferrous ion and defensive effect of intracellular glutathione. Herein, we report a cathepsin B-controllable smart nanomedicine based on the structural and pharmacodynamic characteristics of artemisinin, which employed transferrin-peptide-modified mesoporous silica to codeliver artemisinin and buthionine-sulfoximine, a glutathione scavenger, into cancer cells. As a gatekeeper, the transferrin-peptide can not only target the cancer cells but also supply the extra ferrous iron to catalyze artemisinin to produce excessive ROS to kill cancer cells efficiently. Once the designed nanomedicine attack into lysosome of tumor cells, the cargos of nanomedicine can be released in the presence of cathepsin B to immediately activate self-amplification of oxidative stress by simultaneously elevating the levels of ROS and weakening the levels of glutathione. We anticipate that this rational design strategy provides innovative opportunities for artemisinin in the clinical application of cancer.

Cathepsin-sensitive nanoscale drug delivery systems for cancer therapy and other diseases.

Cathepsins are an important category of enzymes that have attracted great attention for the delivery of drugs to improve the therapeutic outcome of a broad range of nanoscale drug delivery systems. These proteases can be utilized for instance through actuation of polymer-drug conjugates (e.g., triggering the drug release) to bypass limitations of many drug candidates. A substantial amount of work has been witnessed in the design and the evaluation of Cathepsin-sensitive drug delivery systems, especially based on the tetra-peptide sequence (Gly-Phe-Leu-Gly, GFLG) which has been extensively used as a spacer that can be cleaved in the presence of Cathepsin B. This Review Article will give an in-depth overview of the design and the biological evaluation of Cathepsin-sensitive drug delivery systems and their application in different pathologies including cancer before discussing Cathepsin B-cleavable prodrugs under clinical trials.

Advanced glycation end products-related modulation of cathepsin L and NF-κB signalling effectors in retinal pigment epithelium lead to augmented response to TNFα.

The retinal pigment epithelium (RPE) plays a central role in neuroretinal homoeostasis throughout life. Altered proteolysis and inflammatory processes involving RPE contribute to the pathophysiology of age‐related macular degeneration (AMD), but the link between these remains elusive. We report for the first time the effect of advanced glycation end products (AGE)—known to accumulate on the ageing RPE's underlying Bruch's membrane in situ—on both key lysosomal cathepsins and NF‐κB signalling in RPE. Cathepsin L activity and NF‐κB effector levels decreased significantly following 2‐week AGE exposure. Chemical cathepsin L inhibition also decreased total p65 protein levels, indicating that AGE‐related change of NF‐κB effectors in RPE cells may be modulated by cathepsin L. However, upon TNFα stimulation, AGE‐exposed cells had significantly higher ratio of phospho‐p65(Ser536)/total p65 compared to non‐AGEd controls, with an even higher fold increase than in the presence of cathepsin L inhibition alone. Increased proportion of active p65 indicates an AGE‐related activation of NF‐κB signalling in a higher proportion of cells and/or an enhanced response to TNFα. Thus, NF‐κB signalling modulation in the AGEd environment, partially regulated via cathepsin L, is employed by RPE cells as a protective (para‐inflammatory) mechanism but renders them more responsive to pro‐inflammatory stimuli.

Abstract 3115: Physiologic comparisons of five bladder cancer cell lines

Abstract The use of tumor-derived cultured cells continues to be a major resource for understanding the biological activities of tumors and the effects of environmental factors and pharmacological agents on tumors. With comparison of data from the International Cancer Genome Consortium and the Cancer Genome Atlas comes the realization that some frequently used cells lines may not closely share genomic similarity with patient tumors, whereas less frequently used cell lines may share high similarity. For example, the bladder cancer cell line T24 (HTB-4) is more frequently used than other cell lines. We selected five commercially available bladder cancer cell lines, all derived from patient primary tumors, for a comparison of selected proteins, with the intent of determining how similar or dissimilar the cultured cells are. In selection of cultured cell lines, we considered reported grade of tumor from which the cell line was derived and the sex and age of the patient. We evaluated protein expression in newly confluent cultures and in sub-confluent cultures. The following cell lines were selected: RT4 (transitional cell papilloma), 5637 (grade II carcinoma), T24 (grade III carcinoma), HT 1376 (grade III carcinoma) and TCCSUP (grade IV carcinoma). We hypothesized that variations exist between bladder cancer cell lines isolated from low and high-grade carcinomas. Further, we identified physiological characteristics of the different bladder cancer cell lines at both newly confluent and sub confluent culture states as additional parameters for a bladder cancer model. Selection of an appropriate tissue culture cell line(s) and state of confluency are critical considerations in cellular research designed to understand the biological activities of tumors. Growth rates of the five cell lines were determined. Next, the basal-luminal status of the cell lines was determined using molecular subtyping markers (transcription factors GATA3 and p63, Cytokeratin 6, and Estrogen Receptor alpha). The presence of Cathepsin L, a cysteine protease, was evaluated. Further, we evaluated the expression of key proteins in the MAPK pathway (p38 MAPK, SAPK/JNK, and ERK1/2) as indicators of cellular stress. Last, the receptor status of Alpha 7 receptor, the putative receptor for nicotine, was determined. Our results indicate there is a difference in growth rates between the cell lines, with line 5637 having a delayed growth rate. Three cell lines were determined to be basal, and two cell lines were determined as mixed baso/luminal. The RT4 cell line had greater expression of cathepsin L. We observed no significant changes in the protein expression levels of the MAPK pathway nor of the alpha-7 receptor. Our results suggest that there are differences between the five bladder cancer cell lines suggesting that more than one cell line should be used and evaluated prior to beginning experiments to evaluate the potential effects of environmental factors and pharmacological agents. Citation Format: Bonnie L. Richmond, Kyle Damen, Ryan Moore, Alex White, Julia H. Carter. Physiologic comparisons of five bladder cancer cell lines [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3115.

Enzyme/pH-sensitive dendritic polymer-DOX conjugate for cancer treatment

It is in a great demand to design a biodegradable, tumor microenvironment-sensitive drug delivery system to achieve safe and highly efficacious treatment of cancer. Herein, a novel pH/enzyme sensitive dendritic pdiHPMA-DOX conjugate was designed. diHPMA dendritic copolymer with GFLG segments in the branches which are sensitive to the intracellular enzyme of the tumor was prepared through RAFT polymerization. DOX was attached to dendritic diHPMA polymer through a pH-sensitive hydrazone bond. The dendritic pdiHPMA-DOX conjugate self-assembled into nanoparticles with an ideal spherical shape at a mean size of 103 nm. The DOX attached to the polymeric carrier was released in an acidic environment, and the GFLG linker for synthesizing the dendritic vehicle with a high molecular weight ( M W, 220 kDa ) was cleaved to release low M W segments ( 40 kDa ) in the presence of cathepsin B. The dendritic polymeric conjugate was internalized via an endocytic pathway, and then released the anticancer drug, which led to significant cytotoxicity for tumors. The blood circulation time was profoundly prolonged, resulting in high accumulation of DOX into tumors. In vivo anti-tumor experiments with 4T1 tumor bearing mice demonstrated that the conjugate had a better antitumor efficacy in comparison with free DOX. Additionally, body weight measurements and histological examinations indicated that the conjugate showed low toxicities to normal tissues. This dendritic polymeric drug carrier in a response to intracellular enzyme and acidic pH of tumor tissue or cells holds great promise in tumor-targeted therapy.