Targeting prostate carcinoma by G3-C12 peptide conjugated N-(2-hydroxypropyl)methacrylamide copolymers

Improving Pharmacokinetics of Peptides Using Phage Display

Phage display is a versatile method often used in the discovery of peptides that targets disease-related biomarkers. A major advantage of this technology is the ease and cost efficiency of affinity selection, also known as biopanning, to identify novel peptides. While it is relatively straightforward to identify peptides with optimal binding affinity, the pharmacokinetics of the selected peptides often prove to be suboptimal. Therefore, careful consideration of the experimental conditions, including the choice of using in vitro, in situ, or in vivo affinity selections, is essential in generating peptides with high affinity and specificity that also demonstrate desirable pharmacokinetics. Specifically, in vivo biopanning, or the combination of in vitro, in situ, and in vivo affinity selections, has been proven to influence the biodistribution and clearance of peptides and peptide-conjugated nanoparticles. Additionally, the marked difference in properties between peptides and nanoparticles must be considered. While peptide biodistribution depends primarily on physiochemical properties and can be modified by amino acid modifications, the size and shape of nanoparticles also affect both absorption and distribution. Thus, optimization of the desired pharmacokinetic properties should be an important consideration in biopanning strategies to enable the selection of peptides and peptide-conjugated nanoparticles that effectively target biomarkers in vivo.

Safety, Biodistribution, and Dosimetry Study of Meplazumab, a Potential COVID-19 Therapeutic Drug, with 131I-Labeling and SPECT Imaging

Coronavirus disease 2019 (COVID-19) is a serious threat to public health and is in urgent need of specific drugs. Meplazumab, a humanized monoclonal antibody targeting CD147, was confirmed to competitively block the binding between the spike of syndrome coronavirus 2 (SARS-CoV-2) and CD147, making meplazumab a promising candidate drug for COVID-19. In this study, biodistribution and dosimetry of 131I-labeled meplazumab were performed to further evaluate its potential as a therapeutic drug for COVID-19. 131I-meplazumab was both safe and tolerant in mice and healthy volunteers. A biodistribution study was performed in normal mice, and blood samples were used for pharmacokinetic analysis. Three healthy volunteers were included and subjected to single-photon-emission computed tomography (SPECT) imaging of 131I-meplazumab within 2 weeks. The distribution in mice and humans was consistent with the in vivo distribution of CD147. Biodistribution and SPECT imaging results exhibited that the liver was the organ with the highest uptake for both mice and humans. Deiodination of 131I-meplazumab can be observed in vivo, and taking Lugol's solution can protect the thyroid gland effectively. The pharmacokinetic characteristics of 131I-meplazumab in mice and humans best fit the two-compartment model. The clearance half-life (T1/2β) in mice and humans was 117.4 and 223.5 h, respectively. The results indicated that its pharmacokinetic properties in vivo were ideal. The effective dose calculated from healthy volunteers was 0.811 ± 0.260 mSv·MBq-1, which was twice the value calculated from mice. It was safe and feasible to perform human clinical imaging experiments using a diagnostic dose of 131I-meplazumab after thyroid closure by Lugol's solution. This study will provide more experimental basis for advancing the clinical translation of meplazumab and will be valuable in evaluating therapeutic interventions for patients with COVID-19, as well as providing a reference for clinical translation studies of other antibody drugs.

Targeting galectin-driven regulatory circuits in cancer and fibrosis

Galectins are a family of endogenous glycan-binding proteins that have crucial roles in a broad range of physiological and pathological processes. As a group, these proteins use both extracellular and intracellular mechanisms as well as glycan-dependent and independent pathways to reprogramme the fate and function of numerous cell types. Given their multifunctional roles in both tissue fibrosis and cancer, galectins have been identified as potential therapeutic targets for these disorders. Here, we focus on the therapeutic relevance of galectins, particularly galectin 1 (GAL1), GAL3 and GAL9 to tumour progression and fibrotic diseases. We consider an array of galectin-targeted strategies, including small-molecule carbohydrate inhibitors, natural polysaccharides and their derivatives, peptides, peptidomimetics and biological agents (notably, neutralizing monoclonal antibodies and truncated galectins) and discuss their mechanisms of action, selectivity and therapeutic potential in preclinical models of fibrosis and cancer. We also review the results of clinical trials that aim to evaluate the efficacy of galectin inhibitors in patients with idiopathic pulmonary fibrosis, nonalcoholic steatohepatitis and cancer. The rapid pace of glycobiology research, combined with the acute need for drugs to alleviate fibrotic inflammation and overcome resistance to anticancer therapies, will accelerate the translation of anti-galectin therapeutics into clinical practice.

Ligand conjugated lipid-based nanocarriers for cancer theranostics

Cancer is one of the major health-related issues affecting the population worldwide and subsequently accounts for the second-largest death. Genetic and epigenetic modifications in oncogenes or tumor suppressor genes affect the regulatory systems that lead to the initiation and progression of cancer. Conventional methods, including chemotherapy/radiotherapy/appropriate combinational therapy and surgery, are being widely used for theranostics of cancer patients. Surgery is useful in treating localized tumors, but it is ineffective in treating metastatic tumors, which spread to other organs and result in a high recurrence rate and death. Also, the therapeutic application of free drugs is related to substantial issues such as poor absorption, solubility, bioavailability, high degradation rate, short shelf-life, and low therapeutic index. Therefore, these issues can be sorted out using nano lipid-based carriers (NLBCs) as promising drug delivery carriers. Still, at most, they fail to achieve site targeted drug delivery and detection. This can be achieved by selecting a specific ligand/antibody for its cognate receptor molecule expressed on the surface of cancer cell. In this review, we have mainly discussed the various types of ligands used to decorate NLBCs. A list of the ligands used to design nanocarriers to target malignant cells has been extensively undertaken. The approved ligand decorated lipid-based nanomedicines with their clinical status has been explained in tabulated form to provide a wider scope to the readers regarding ligand coupled NLBCs. This article is protected by copyright. All rights reserved.

Mitochondrial targeting of potent nanoparticulated drugs in combating diseases

Mitochondrial dysfunction, characterized by the electron transport chain (ETC) leakage and reduced adenosine tri-phosphate synthesis, occurs primarily due to free radicals -induced mutations in either the mitochondrial deoxyribonucleic acid (mtDNA) or nuclear (n) DNA caused by pathogenic infections, toxicant exposures, adverse drug-effects, or other environmental exposures, leading to secondary dysfunction affecting ischemic, diabetic, cancerous, and degenerative diseases. In these concerns, mitochondria-targeted remedies may include a significant role in the protection and treatment of mitochondrial function to enhance its activity. Coenzyme Q10 pyridinol and pyrimidinol antioxidant analogues and other potent drug-compounds for their multifunctional radical quencher and other anti-toxic activities may take a significant therapeutic effectivity for ameliorating mitochondrial dysfunction. Moreover, the encapsulation of these bioactive ligands-attached potent compounds in vesicular system may enable them a superb biological effective for the treatment of mitochondria-targeted dysfunction-related diseases with least side effects. This review depicts mainly on mitochondrial enzymatic dysfunction and their amelioration by potent drugs with the usages of nanoparticulated delivery system against mitochondria-affected diseases.

Unraveling How Tumor-Derived Galectins Contribute to Anti-Cancer Immunity Failure

Simple Summary

This review compiles our current knowledge of one of the main pathways activated by tumors to escape immune attack. Indeed, it integrates the current understanding of how tumor-derived circulating galectins affect the elicitation of effective anti-tumor immunity. It focuses on several relevant topics: which are the main galectins produced by tumors, how soluble galectins circulate throughout biological liquids (taking a body-settled gradient concentration into account), the conditions required for the galectins’ functions to be accomplished at the tumor and tumor-distant sites, and how the physicochemical properties of the microenvironment in each tissue determine their functions. These are no mere semantic definitions as they define which functions can be performed in said tissues instead. Finally, we discuss the promising future of galectins as targets in cancer immunotherapy and some outstanding questions in the field.

Abstract

Current data indicates that anti-tumor T cell-mediated immunity correlates with a better prognosis in cancer patients. However, it has widely been demonstrated that tumor cells negatively manage immune attack by activating several immune-suppressive mechanisms. It is, therefore, essential to fully understand how lymphocytes are activated in a tumor microenvironment and, above all, how to prevent these cells from becoming dysfunctional. Tumors produce galectins-1, -3, -7, -8, and -9 as one of the major molecular mechanisms to evade immune control of tumor development. These galectins impact different steps in the establishment of the anti-tumor immune responses. Here, we carry out a critical dissection on the mechanisms through which tumor-derived galectins can influence the production and the functionality of anti-tumor T lymphocytes. This knowledge may help us design more effective immunotherapies to treat human cancers.

Targeting Galectins With Glycomimetics

Among glycan-binding proteins, galectins, β-galactoside-binding lectins, exhibit relevant biological roles and are implicated in many diseases, such as cancer and inflammation. Their involvement in crucial pathologies makes them interesting targets for drug discovery. In this review, we gather the last approaches toward the specific design of glycomimetics as potential drugs against galectins. Different approaches, either using specific glycomimetic molecules decorated with key functional groups or employing multivalent presentations of lactose and N-acetyl lactosamine analogs, have provided promising results for binding and modulating different galectins. The review highlights the results obtained with these approximations, from the employment of S-glycosyl compounds to peptidomimetics and multivalent glycopolymers, mostly employed to recognize and/or detect hGal-1 and hGal-3.

Galectin Targeted Therapy in Oncology: Current Knowledge and Perspectives

The incidence and mortality of cancer have increased over the past decades. Significant progress has been made in understanding the underpinnings of this disease and developing therapies. Despite this, cancer still remains a major therapeutic challenge. Current therapeutic research has targeted several aspects of the disease such as cancer development, growth, angiogenesis and metastases. Many molecular and cellular mechanisms remain unknown and current therapies have so far failed to meet their intended potential. Recent studies show that glycans, especially oligosaccharide chains, may play a role in carcinogenesis as recognition patterns for galectins. Galectins are members of the lectin family, which show high affinity for β-galactosides. The galectin–glycan conjugate plays a fundamental role in metastasis, angiogenesis, tumor immunity, proliferation and apoptosis. Galectins’ action is mediated by a structure containing at least one carbohydrate recognition domain (CRD). The potential prognostic value of galectins has been described in several neoplasms and helps clinicians predict disease outcome and determine therapeutic interventions. Currently, new therapeutic strategies involve the use of inhibitors such as competitive carbohydrates, small non-carbohydrate binding molecules and antibodies. This review outlines our current knowledge regarding the mechanism of action and potential therapy implications of galectins in cancer.

Two birds, one stone: dual targeting of the cancer cell surface and subcellular mitochondria by the galectin-3-binding peptide G3-C12

Active tumor-targeting approaches using specific ligands have drawn considerable attention over the years. However, a single ligand often fails to simultaneously target the cancer cell surface and subcellular organelles, which limits the maximum therapeutic efficacy of delivered drugs. We describe a polymeric delivery system modified with the G3-C12 peptide for sequential dual targeting. In this study, galectin-3-targeted G3-C12 peptide was conjugated onto the N-(2-hydroxypropyl) methacrylamide (HPMA) copolymer for the delivery of _D(KLAKLAK)₂ (KLA) peptide. G3-C12-HPMA-KLA exhibited increased receptor-mediated internalization into galectin-3-overexpressing PC-3 cells. Furthermore, G3-C12 peptide also directed HPMA-KLA conjugates to mitochondria. This occurred because the apoptosis signal triggered the accumulation of galectin-3 in mitochondria, and the G3-C12 peptide that specifically bound to galectin-3 was trafficked along with its receptor intracellularly. As a result, G3-C12-HPMA-KLA disrupted the mitochondrial membrane, increased the generation of reactive oxygen species (ROS) and induced cytochrome c release, which ultimately resulted in enhanced cytotoxicity. An in vivo study revealed that the G3-C12 peptide significantly enhanced the tumor accumulation of the KLA conjugate. In addition, G3-C12-HPMA-KLA exhibited the best therapeutic efficacy and greatly improved the animal survival rate. Our work demonstrates that G3-C12 is a promising ligand with dual-targeting functionality.

Biodegradable brush-type copolymer modified with targeting peptide as a nanoscopic platform for targeting drug delivery to treat castration-resistant prostate cancer

Well-defined amphiphilic tumor-targeting brush-type copolymers, poly(oligo(ethylene glycol) monomethyl ether methacrylate-co-G3-C12)-g-poly(ε-caprolactone) (P(OEGMA-co-G3-C12)-g- PCL), were synthesized by the combination of ring-opening polymerization (ROP), reversible addition-fragmentation transfer (RAFT) polymerization and polymer post-functionalization, in which G3-C12 was castration-resistant prostate cancer (CRPC) targeting peptide. The obtained polymers were then employed for the targeted treatment of CRPC by delivering a hydrophobic anticancer drug (bufalin, BUF). Polymerizable monomer, 3-((2-(methacryloyloxy)ethyl)thio)propanoic acid (BSMA) and PCL-based macromolecular monomer (PCLMA) were synthesized at first. RAFT polymerization of OEGMA, BSMA, and PCLMA afforded amphiphilic brush-type copolymers, P(OEGMA-co-BSMA)-g-PCL. Post-functionalization of the obtained polymers with G3-C12 led to the formation of the final amphiphilic targeting brush-type copolymers, P(OEGMA-co-G3-C12)-g- PCL. In aqueous media, P(OEGMA-co-G3-C12)-g-PCL self-assembles into micelles with a hydrodynamic diameter (Dh) of ∼66.1±0.44nm. It was demonstrated that the obtained micellar nanoparticles exhibited good biocompatibility and biodegradability. Besides, BUF-loaded micellar nanoparticles assembled from P(OEGMA-co-G3-C12)-g-PCL, BUF-NP-(G3-C12), showed a controlled drug release in vitro and improved anticancer efficacy both in vitro and in vivo.

Turning-Off Signaling by Siglecs, Selectins, and Galectins: Chemical Inhibition of Glycan-Dependent Interactions in Cancer

Aberrant glycosylation, a common feature associated with malignancy, has been implicated in important events during cancer progression. Our understanding of the role of glycans in cancer has grown exponentially in the last few years, concurrent with important advances in glycomics and glycoproteomic technologies, paving the way for the validation of a number of glycan structures as potential glycobiomarkers. However, the molecular bases underlying cancer-associated glycan modifications are still far from understood. Glycans exhibit a natural heterogeneity, crucial for their diverse functional roles as specific carriers of biologically relevant information. This information is decoded by families of proteins named lectins, including sialic acid-binding immunoglobulin (Ig)-like lectins (siglecs), C-type lectin receptors (CLRs), and galectins. Siglecs are primarily expressed on the surface of immune cells and differentially control innate and adaptive immune responses. Among CLRs, selectins are a family of cell adhesion molecules that mediate interactions between cancer cells and platelets, leukocytes, and endothelial cells, thus facilitating tumor cell invasion and metastasis. Galectins, a family of soluble proteins that bind β-galactoside-containing glycans, have been implicated in diverse events associated with cancer biology such as apoptosis, homotypic cell aggregation, angiogenesis, cell migration, and tumor-immune escape. Consequently, individual members of these lectin families have become promising targets for the design of novel anticancer therapies. During the past decade, a number of inhibitors of lectin–glycan interactions have been developed including small-molecule inhibitors, multivalent saccharide ligands, and more recently peptides and peptidomimetics have offered alternatives for tackling tumor progression. In this article, we review the current status of the discovery and development of chemical lectin inhibitors and discuss novel strategies to limit cancer progression by targeting lectin–glycan interactions.

G3-C12 Peptide Reverses Galectin-3 from Foe to Friend for Active Targeting Cancer Treatment

Galectin-3 is overexpressed by numerous carcinomas and is a potential target for active tumor treatments. On the other hand, galectin-3 also plays a key role in cancer progression and prevents cells from undergoing apoptosis, thereby offsetting the benefits of active targeting drugs. However, the relative contribution of the protective antiapoptotic effects of galectin-3 and the proapoptotic effects of galectin-3-targeted therapies has remained yet unrevealed. Here, we show that a galectin-3-binding peptide G3-C12 could reverse galectin-3 from foe to friend for active targeting delivery system. Results showed G3-C12 modified N-(2-hydroxypropyl)methacrylamide copolymer doxorubicin conjugates (G3-C12-HPMA-Dox) could internalize into galectin-3 overexpressed PC-3 cells via a highly specific ligand-receptor pathway (2.2 times higher cellular internalization than HPMA-Dox). The internalized Dox stimulated the translocation of galectin-3 to the mitochondria to prevent from apoptosis. In turn, this caused G3-C12-HPMA-Dox to concentrate into the mitochondria after binding to galectin-3 intracellularly. Initially, mitochondrial galectin-3 weakened Dox-induced mitochondrial damage; however, as time progressed, G3-C12 active-mediation allowed increasing amounts of Dox to be delivered to the mitochondria, which eventually induced higher level of apoptosis than nontargeted copolymers. In addition, G3-C12 downregulates galectin-3 expression, 0.43 times lower than control cells, which could possibly be responsible for the suppressed cell migration. Thus, G3-C12 peptide exerts sequential targeting to both cell membrane and mitochondria via regulating galectin-3, and eventually reverses and overcomes the protective effects of galectin-3; therefore, it could be a promising agent for the treatment of galectin-3-overexpressing cancers.

Improvement of anti-tumor abilities on human non-small cell lung carcinoma by micellization and cross-linking of N-(2-hydroxypropyl) methacrylamide copolymers

Non-small cell lung carcinoma is one of the most frequently occurred cancers with a very high rate of recurrence. Self-assembly N-(2-hydroxypropyl) methacrylamide (HPMA) micelles and cross-linked micelles were developed to improve antitumor ability of linear HPMA copolymer. The characters of HPMA micelles were investigated and compared using human non-small cell lung carcinoma 3-D culture model and nude mice xenograft model. Cross-linked micelles showed highest cytotoxicity on A549 cell monolayers after a short time treatment in vitro. Moreover, both of the two micelles exhibited better in vitro anti-tumor activity on A549 tumor spheroids than linear HPMA conjugates especially the cross-linked micelles. On BALB/c nude mice bearing A549 xenograft tumors, the cross-linked micelles exhibited the greatest tumor accumulation and the best anti-tumor activity due to the highly improved stabilities and the more pronounced enhanced permeability and retention (EPR) effect, which were followed by the non-cross-linked micelles. Meanwhile, neither the two micelles nor the linear HPMA copolymers showed significant toxicity on the main organs of mice while free doxorubicin (DOX) showed obvious cardiac toxicity. All the results suggested that micellization improved the anti-tumor activity of HPMA copolymers on A549 human non-small cell lung carcinoma, furthermore, cross-linked HPMA copolymer micelles with pH-sensitivity and biodegradability showed more excellent anti-tumor activity.

Polymeric nanomedicine for tumor-targeted combination therapy to elicit synergistic genotoxicity against prostate cancer

To improve the therapeutic efficacy of anticancer combination therapy, we designed a nanoplatform based on N-(2-hydroxypropyl) methacrylamide (HPMA) copolymers that allows covalent bonding of two chemotherapeutics acting via different anticancer mechanisms and that can enter target cells by receptor-mediated endocytosis. Doxorubicin (DOX) was covalently conjugated to a nanosized HPMA copolymer using a pH-sensitive hydrazone bond and 5-fluorouracil (5-Fu) was conjugated to the same backbone using an enzymatically degradable oligopeptide Gly-Phe-Leu-Gly sequence. Then, the conjugate was decorated with galectin-3 targeting peptide G3-C12 [P-(G3-C12)-DOX-Fu]. The two drugs showed similar in vitro release profiles, suggesting that they may be able to work synergistically in the codelivery system. In galectin-3 overexpressed PC-3 human prostate carcinoma cells, P-(G3-C12)-DOX-Fu surprisingly exhibited comparable cytotoxicity to free DOX at high concentration by increasing cell internalization and exerting synergistic genotoxic effects of cell cycle arrest, caspase-3 activation, and DNA damage. In mice bearing PC-3 tumor xenografts, the use of tumor-targeting ligand substantially enhanced the intracellular delivery of P-(G3-C12)-DOX-Fu in tumors. The targeted dual drug-loaded conjugate inhibited tumor growth to a greater extent (tumor inhibition of 81.6%) than did nontargeted P-DOX-Fu (71.2%), P-DOX (63%), DOX·HCl (40.5%), P-Fu (32.0%), or 5-Fu (14.6%), without inducing any obvious side effects. These results demonstrate the potential of synergistic combination therapy using targeted nanocarriers for efficient treatment of prostate cancer.