Hyaluronic acid-modified polyamidoamine dendrimer G5-entrapped gold nanoparticles delivering METase gene inhibits gastric tumor growth via targeting CD44+ gastric cancer cells

The Role of Methionine Restriction in Gastric Cancer: A Summary of Mechanisms and a Discussion on Tumor Heterogeneity

Gastric cancer is ranked as the fifth most prevalent cancer globally and has long been a topic of passionate discussion among numerous individuals. However, the incidence of gastric cancer in society has not decreased, but instead has shown a gradual increase in recent years. For more than a decade, the treatment effect of gastric cancer has not been significantly improved. This is attributed to the heterogeneity of cancer, which makes popular targeted therapies ineffective. Methionine is an essential amino acid, and many studies have shown that it is involved in the development of gastric cancer. Our study aimed to review the literature on methionine and gastric cancer, describing its mechanism of action to show that tumor heterogeneity in gastric cancer does not hinder the effectiveness of methionine-restricted therapies. This research also aimed to provide insight into the inhibition of gastric cancer through metabolic reprogramming with methionine-restricted therapies, thereby demonstrating their potential as adjuvant treatments for gastric cancer.

Upregulation of E-cadherin by the combination of methionine restriction and HDAC2 intervention for inhibiting gastric carcinoma metastasis

Invasion and metastasis are the leading causes of death in individuals with malignant tumors, including gastric cancer. In this study, we aim to explore the effect and related mechanisms of methionine restriction (MR) on gastric carcinoma metastasis. In the MR cell model, gastric carcinoma cells are cultured in the MR medium, and in the animal model, BALB/c nude rodents are administered with a methionine-free diet after receiving injections of MKN45 cells into the caudal vein. Transwell assay is used to detect cell invasion and migration. Chromatin immunoprecipitation is performed to investigate the levels of H3K9me2, H3K27Ac, and H3K27me3 in the E-cadherin promoter. The results show that MR inhibits gastric carcinoma cell migration, invasion, and lung metastasis. MR increases E-cadherin while reducing the H3K27me3 level in the E-cadherin promoter. E-cadherin expression in gastric carcinoma cells is adversely regulated by HDAC2. Overexpressing HDAC2 reduces the H3K27Ac level in the E-cadherin promoter, while interfering with HDAC2 increases the H3K27Ac level. HDAC2 interference under MR conditions further upregulates E-cadherin expression and inhibits gastric carcinoma cell migration, invasion, and lung metastasis. MR combined with HDAC2 interference promotes E-cadherin expression by mediating the methylation and acetylation of E-cadherin, thus inhibiting the invasion, migration, and lung metastasis of gastric carcinoma cells. Our study provides a new theoretical basis for the inhibitory effect of MR on gastric cancer.

Metal nanoparticles as a potential technique for the diagnosis and treatment of gastrointestinal cancer: a comprehensive review

Gastrointestinal (GI) cancer is a major health problem worldwide, and current diagnostic and therapeutic approaches are often inadequate. Various metallic nanoparticles (MNPs) have been widely studied for several biomedical applications, including cancer. They may potentially overcome the challenges associated with conventional chemotherapy and significantly impact the overall survival of GI cancer patients. Functionalized MNPs with targeted ligands provide more efficient localization of tumor energy deposition, better solubility and stability, and specific targeting properties. In addition to enhanced therapeutic efficacy, MNPs are also a diagnostic tool for molecular imaging of malignant lesions, enabling non-invasive imaging or detection of tumor-specific or tumor-associated antigens. MNP-based therapeutic systems enable simultaneous stability and solubility of encapsulated drugs and regulate the delivery of therapeutic agents directly to tumor cells, which improves therapeutic efficacy and minimizes drug toxicity and leakage into normal cells. However, metal nanoparticles have been shown to have a cytotoxic effect on cells in vitro. This can be a concern when using metal nanoparticles for cancer treatment, as they may also kill healthy cells in addition to cancer cells. In this review, we provide an overview of the current state of the field, including preparation methods of MNPs, clinical applications, and advances in their use in targeted GI cancer therapy, as well as the advantages and limitations of using metal nanoparticles for the diagnosis and treatment of gastrointestinal cancer such as potential toxicity. We also discuss potential future directions and areas for further research, including the development of novel MNP-based approaches and the optimization of existing approaches.

Assessment of the influence of gold nanoparticles stabilized with PAMAM dendrimers on HUVEC barrier cells

Civilization diseases, cancer, frequent mutations of viruses and other pathogens constitute the need to look for new drugs, as well as systems for their targeted delivery. One of the promising way of using drugs is supplying them by linking to nanostructures. One of the solution for the development of nanobiomedicine are metallic nanoparticles stabilized with various polymer structures. In this report, we present the synthesis of gold nanoparticles, their stabilization with polyamidoamine (PAMAM) dendrimers with ethylenediamine core and the characteristics of the obtained product (AuNPs/PAMAM). The presence, size and morphology of synthesized gold nanoparticles were evaluated by ultraviolet-visible light spectroscopy, transmission electron microscopy and atomic force microscopy. The hydrodynamic radius distribution of the colloids was analyzed by dynamic light scattering technique. Additionally, the cytotoxicity and changes in mechanical properties of human umbilical vein endothelial cell line (HUVEC) cells caused by AuNPs/PAMAM were assessed. The results of studies on the nanomechanical properties of cells suggest a two-step changes in cell elasticity as a response to contact with nanoparticles. When using AuNPs/PAMAM in lower concentrations, no changes in cell viability were observed and the cells were softer than untreated cells. When higher concentrations were used, a decrease in the cells viability to about 80 % were observed, as well as non-physiological stiffening of the cells. The presented results may play a significant role in the development of nanomedicine.

Dendrimers as Modifiers of Inorganic Nanoparticles for Therapeutic Delivery in Cancer

The formulation of nanoscale systems with well-defined sizes and shapes is of great interest in applications such as drug and gene delivery, diagnostics and imaging. Dendrimers are polymers that have attracted interest due to their size, shape, branching length, amine density, and surface functionalities. These unique characteristics of dendrimers set them apart from other polymers, their ability to modify nanoparticles (NPs) for biomedical applications. Dendrimers are spherical with multiple layers over their central core, each representing a generation. Their amphiphilic nature and hollow structure allow for the incorporation of multiple drugs or genes, in addition to enabling easy surface modification with cellular receptor-targeting moieties to ensure site-specific delivery of therapeutics. Dendrimers are employed in chemotherapeutic applications for the delivery of anticancer drugs. There are many inorganic NPs currently being investigated for cancer therapy, each with their own unique biological, chemical, and physical properties. To favor biomedical applications, inorganic NPs require suitable polymers to ensure stability, biodegradability and target specificity. The success of dendrimers is dependent on their unique structure, good bioavailability and stability. In this review, we describe the properties of dendrimers and their use as modifiers of inorganic NPs for enhanced therapeutic delivery. Herein, we review the significant developments in this area from 2015 to 2022. Databases including Web of Science, Scopus, Google Scholar, Science Direct, BioMed Central (BMC), and PubMed were searched for articles using dendrimers, inorganic nanoparticles and cancer as keywords.

Targeting cancer stem cells with polymer nanoparticles for gastrointestinal cancer treatment

Nanomaterials are developing rapidly in the medical field, bringing new hope for treating various refractory diseases. Among them, polymer nanomaterials, with their excellent properties, have been used to treat various diseases, such as malignant tumors, diabetes, and nervous system diseases. Gastrointestinal cancer is among the cancers with the highest morbidity and mortality worldwide. Cancer stem cells are believed to play an important role in the occurrence and development of tumors. This article summarizes the characteristics of gastrointestinal cancer stem cells and reviews the latest research progress in treating gastrointestinal malignant tumors using polymer nanoparticles to target cancer stem cells. In addition, the review article highlights the potential of polymer nanoparticles in targeting gastrointestinal cancer stem cells.

Dendrimers as Non-Viral Vectors in Gene-Directed Enzyme Prodrug Therapy

Gene-directed enzyme prodrug therapy (GDEPT) has been intensively studied as a promising new strategy of prodrug delivery, with its main advantages being represented by an enhanced efficacy and a reduced off-target toxicity of the active drug. In recent years, numerous therapeutic systems based on GDEPT strategy have entered clinical trials. In order to deliver the desired gene at a specific site of action, this therapeutic approach uses vectors divided in two major categories, viral vectors and non-viral vectors, with the latter being represented by chemical delivery agents. There is considerable interest in the development of non-viral vectors due to their decreased immunogenicity, higher specificity, ease of synthesis and greater flexibility for subsequent modulations. Dendrimers used as delivery vehicles offer many advantages, such as: nanoscale size, precise molecular weight, increased solubility, high load capacity, high bioavailability and low immunogenicity. The aim of the present work was to provide a comprehensive overview of the recent advances regarding the use of dendrimers as non-viral carriers in the GDEPT therapy.

Recent Advances in Preclinical Research Using PAMAM Dendrimers for Cancer Gene Therapy

Carriers of genetic material are divided into vectors of viral and non-viral origin. Viral carriers are already successfully used in experimental gene therapies, but despite advantages such as their high transfection efficiency and the wide knowledge of their practical potential, the remaining disadvantages, namely, their low capacity and complex manufacturing process, based on biological systems, are major limitations prior to their broad implementation in the clinical setting. The application of non-viral carriers in gene therapy is one of the available approaches. Poly(amidoamine) (PAMAM) dendrimers are repetitively branched, three-dimensional molecules, made of amide and amine subunits, possessing unique physiochemical properties. Surface and internal modifications improve their physicochemical properties, enabling the increase in cellular specificity and transfection efficiency and a reduction in cytotoxicity toward healthy cells. During the last 10 years of research on PAMAM dendrimers, three modification strategies have commonly been used: (1) surface modification with functional groups; (2) hybrid vector formation; (3) creation of supramolecular self-assemblies. This review describes and summarizes recent studies exploring the development of PAMAM dendrimers in anticancer gene therapies, evaluating the advantages and disadvantages of the modification approaches and the nanomedicine regulatory issues preventing their translation into the clinical setting, and highlighting important areas for further development and possible steps that seem promising in terms of development of PAMAM as a carrier of genetic material.

Hybrid Nanosystems for Biomedical Applications

Inorganic/organic hybrid nanosystems have been increasingly developed for their versatility and efficacy at overcoming obstacles not readily surmounted by nonhybridized counterparts. Currently, hybrid nanosystems are implemented for gene therapy, drug delivery, and phototherapy in addition to tissue regeneration, vaccines, antibacterials, biomolecule detection, imaging probes, and theranostics. Though diverse, these nanosystems can be classified according to foundational inorganic/organic components, accessory moieties, and architecture of hybridization. Within this Review, we begin by providing a historical context for the development of biomedical hybrid nanosystems before describing the properties, synthesis, and characterization of their component building blocks. Afterward, we introduce the architectures of hybridization and highlight recent biomedical nanosystem developments by area of application, emphasizing hybrids of distinctive utility and innovation. Finally, we draw attention to ongoing clinical trials before recapping our discussion of hybrid nanosystems and providing a perspective on the future of the field.

Targeted Combination of Antioxidative and Anti-Inflammatory Therapy of Rheumatoid Arthritis using Multifunctional Dendrimer-Entrapped Gold Nanoparticles as a Platform

Abundant reactive oxygen species and tumor necrosis factor-α (TNF-α) cytokine supply of M1-type macrophages boost rheumatoid arthritis (RA) pathological process. For efficient RA therapy, here a multifunctional nanoplatform is presented based on generation 5 (G5) poly(amidoamine) dendrimer-entrapped gold nanoparticles (Au DENPs) to achieve co-delivery of antioxidant alpha-tocopheryl succinate (α-TOS) and anti-inflammatory anti-TNF-α siRNA to macrophage cells. G5 dendrimers with amine termini are sequentially functionalized with 1,3-propane sultone (1,3-PS), α-TOS through a polyethylene glycol (PEG) spacer, and PEGylated folic acid (FA), and subsequently entrapped with Au NPs. The generated functional Au DENPs exhibit desired cytocompatibility, zwitterion-rendered antifouling property, and FA-mediated targeting specificity, enabling serum-enhanced siRNA delivery to M1-type macrophage cells. Meanwhile, the attached α-TOS affords enhanced oxidation resistance of macrophage cells. In vivo investigation shows that the treatment of a collagen-induced arthritis mouse model using α-TOS-modified Au DENPs/TNF-α siRNA polyplexes can achieve excellent combination therapy effect in inflammatory cytokines downregulation of RA lesion and bone erosions. The therapeutic efficacy is also supported by 3D micro-computed tomography analysis and TNF-α cytokine reduction of RA lesion joints in the mRNA, protein, and histology levels. The created multifunctional nanoplatform may be employed in antioxidative and anti-inflammatory combination therapy of RA.

Methionine represses the autophagy of gastric cancer stem cells via promoting the methylation and phosphorylation of RAB37

This study focused on the role of methionine (MET) in the autophagy of gastric cancer stem cells (GCSCs) and aims to elaborate its regulatory mechanism. In the present study, the GCSCs were isolated from human gastric cancer cell lines using an anti-CD44 antibody, and then cultured in MET⁺ homocysteine (HCY)^- or MET^-HCY⁺ medium. In MET⁺HCY^-treated GCSCs, autophagy was suppressed, the methylation and phosphorylation of RAB37 were elevated, and miR-200b expression was down-regulated. Lentiviral vector (LV-) carrying methionine-γ lyase (an enzyme that could specifically lyse MET; Metase) promoted autophagy, reduced the methylation and phosphorylation of RAB37, and up-regulated miR-200b expression in MET⁺HCY^--treated GCSCs. Then, we found that miR-200b suppressed the expression of protein kinase C α (PKCα), a protein that could inactivate RAB37 through promoting its phosphorylation. LV-Metase down-regulated RAB37 phosphorylation via miR-200b/PKCα, thus promoting the RAB37-mediated autophagy and suppressing cell viability in MET⁺HCY^-treated GCSCs. Finally, the in vivo study proved that LV-Metase treatment inhibited tumor growth through up-regulating RAB37 expression. In conclusion, MET suppressed RAB37 expression via enhancing its methylation and suppressed RAB37 activity via miR-200b/PKCα axis, thus repressing RAB37-mediated autophagy in GCSCs. The supplementation of Metase lysed MET, thus inducing the autophagy of GCSCs and inhibiting tumor growth.

The antilymphatic metastatic effect of hyaluronic acid in a mouse model of oral squamous cell carcinoma

Objectives: Lymphatic metastasis is the main cause of low patient survival in cases of oral squamous cell carcinoma (OSCC). Several animal models have been established to uncover the mechanism that regulates lymph node metastasis of OSCC cells. Unfortunately, these models often take a long time to establish. The prolonged tumor burden can lead to animal cachexia, which may ultimately affect the experimental outcome. To overcome the disadvantages of these models, we established an orthotopic metastatic animal model of OSCC that showed quick lymph node metastasis potential.Results: DiR dye-labeled CAL27 cells were injected into tongue tissues of BALB/c nude mice, and the cells metastasized to lymph nodes on day 3. Metastasis was monitored using an in vivo imaging system and confirmed by histological observation. Using this model, we investigated the role of hyaluronic acid (HA) on the cervical metastasis of OSCC cells. Surprisingly, we found that the presence of HA significantly reduced the incidence of metastasis to cervical lymph nodes compared with the control group. Further analysis revealed that the presence of exogenous HA promoted mesenchymal-epithelial transition (MET) in primary tumors while reducing the metastatic potential of OSCC.Conclusion: Our findings confirmed the establishment of a fast and reliable lymphatic metastatic mouse model of OSCC that can be used for investigating metastatic mechanisms and analyzing various antimetastasis strategies. An equally important discovery is the antimetastatic property of HA, which could provide a potential therapeutic strategy for OSCC.

Nanoparticles guided drug delivery and imaging in gastric cancer

Gastric cancer represents a deadly malignancy worldwide, yet current therapeutic regimens remain ineffective. Nanoparticle (NP) -based solutions could allow the design of novel therapeutic methods to eliminate this fatal disease. NPs typically carry out a significant role in multifunctional, multimodal imaging, and drug delivery carriers. In the recent decade, they have emerged as candidate approaches for the design of novel treatment strategies. Tumor nanotherapeutics characteristically possess various distinct advantages compared to conventional anti-cancer medications, which suffer from nonspecific bio-distribution, low solubility, and poor bioavailability. In this review, we will discuss the application of NPs in diagnosis and controlled drug delivery in gastric cancer (GC). We will focus on various NPs-based strategies employed against GC.

Co-delivery of doxorubicin and TRAIL plasmid by modified PAMAM dendrimer in colon cancer cells, in vitro and in vivo evaluation

One strategy for cancer treatment is combination therapy using nanoparticles (NPs), which has resulted in enhanced anti-cancer effects and reduced cytotoxicity of therapeutic agents. Polyamidoamine dendrimer (PAMAM) has attracted considerable attention because of its potential applications ranging from drug delivery to molecular encapsulation and gene therapy. In this study, PAMAM G5 modified with cholesteryl chloroformate and alkyl-PEG was applied for co-delivery of doxorubicin (DOX) and plasmid encoding TRAIL into colon cancer cells, in vitro and in vivo. The results showed DOX was efficiently encapsulated in modified carrier (M-PAMAM) with loading level about 90%, and the resulting DOX-loaded M-PAMAM complexed with TRAIL plasmid showed much stronger antitumor effect than M-PAMAM containing DOX or TRAIL plasmid. On the other hand, the obtained results demonstrated that the treatment of mice bearing C26 colon carcinoma with this developed co-delivery system significantly decreased tumor growth rate. Thus, this modified PAMAM G5 can be considered as a potential carrier for co-delivery of drug and gene in cancer therapy.

Hyaluronan-CD44 axis orchestrates cancer stem cell functions

The prominent role of CD44 in tumor cell signaling together with its establishment as a cancer stem cell (CSC) marker for various tumor entities imply a key role for CD44 in CSC functional properties. Hyaluronan, the main ligand of CD44, is a major constituent of CSC niche and, therefore, the hyaluronan-CD44 signaling axis is of functional importance in this special microenvironment. This review aims to provide recent advances in the importance of hyaluronan-CD44 interactions in the acquisition and maintenance of a CSC phenotype. Hyaluronan-CD44 axis has a substantial impact on stemness properties of CSCs and drug resistance through induction of EMT program, oxidative stress resistance, secretion of extracellular vesicles/exosomes and epigenetic control. Potential therapeutic approaches targeting CSCs based on the hyaluronan-CD44 axis are also presented.

Multiply clustered gold-based nanoparticles complexed with exogenous pDNA achieve prolonged gene expression in stem cells

Development of a stable and prolonged gene delivery system is a key goal in the gene therapy field. To this end, we designed and fabricated a gene delivery system based on multiply-clustered gold particles that could achieve prolonged gene delivery in stem cells, leading to improved induction of differentiation.

Methods: Inorganic gold nanoparticles (AuNPs) underwent three rounds of complexation with catechol-functionalized polyethyleneimine (CPEI) and plasmid DNAs (pDNAs), in that order, with addition of heparin (HP) between rounds, yielding multiply-clustered gold-based nanoparticles (mCGNPs). Via metal-catechol group interactions, the AuNP surface was easily coordinated with positively charged CPEIs, which in turn allowed binding of pDNAs.

Results: Negatively charged HP was encapsulated with the positive charge of CPEIs via electrostatic interactions, making the NPs more compact. Repeating the complexation process yielded mCGNPs with improved transfection efficiency in human mesenchymal stem cells (hMSCs); moreover, these particles exhibited lower cytotoxicity and longer expression of pDNAs than conventional NPs. This design was applied to induction of chondrogenesis in hMSCs using pDNA harboring SOX9, an important chondrogenic transcription factor. Prolonged expression of SOX9 induced by mCGNPs triggered expression of chondrocyte extracellular matrix (ECM) protein after 14 days, leading to more efficient chondrogenic differentiation in vitro and in vivo.

Ruthenium dendrimers against acute promyelocytic leukemia: in vitro studies on HL-60 cells

Coordination of ruthenium arene fragments on carbosilane dendrimers' surface greatly increases their antitumor properties. Newly synthetized ruthenium dendrimers are water-soluble, monodisperse and stable. Since carbosilane dendrimers are good carriers of drugs and genes, the presence of ruthenium in their structure makes them promising candidates for new drug delivery systems with improved antitumor potential. Carbosilane ruthenium dendrimers are more toxic to cancer cells than normal cells. Results of several in vitro studies applied here indicate that carbosilane ruthenium dendrimers induce apoptosis in promyelocytic leukemia HL-60 cells.

Metabolic targeting with recombinant methioninase combined with palbociclib regresses a doxorubicin-resistant dedifferentiated liposarcoma

Liposarcoma is the most common type of soft tissue sarcoma. Among the subtypes of liposarcoma, dedifferentiated liposarcoma (DDLPS) is recalcitrant and has the lowest survival rate. The aim of the present study is to determine the efficacy of metabolic targeting with recombinant methioninase (rMETase) combined with palbociclib (PAL) against a doxorubicin (DOX)-resistant DDLPS in a patient-derived orthotopic xenograft (PDOX) model. A resected tumor from a patient with recurrent high-grade DDLPS in the right retroperitoneum was grown orthotopically in the right retroperitoneum of nude mice to establish a PDOX model. The PDOX models were randomized into the following groups when tumor volume reached 100 mm³: G1, control without treatment; G2, DOX; G3, PAL; G4, recombinant methioninase (rMETase); G5, PAL combined with rMETase. Tumor length and width were measured both pre- and post-treatment. On day 14 after initiation, all treatments significantly inhibited tumor growth compared to the untreated control except DOX. PAL combined with rMETase was significantly more effective than both DOX, rMETase alone, and PAL alone. Combining PAL and rMETase significantly regressed tumor volume on day 14 after initiation of treatment and was the only treatment to do so. The relative body weight on day 14 compared with day 0 did not significantly differ between each treatment group. The results of the present study indicate the powerful combination of rMETase and PAL should be tested clinically against DDLPS in the near future.

METase promotes cell autophagy via promoting SNHG5 and suppressing miR-20a in gastric cancer

BACKGROUND

Gastric cancer (GC) severely threatens human life, and METase seemed to inhibit tumor growth. However, the potential mechanism underlying it is still unclear.

METHODS

Both clinical tissues and cell lines were used in the present study. SNHG5 and miR-20a expressions were determined using real-time PCR. Western blot was performed to determine the expression of autophagy-related proteins. The interaction between miR-20a and SNHG5 was determined using luciferase reporter assay and RNA immunoprecipitation (RIP).

RESULTS

The expression of SNHG5 was decreased in GC tissues and cell lines. Overexpressed METase significantly promoted cell apoptosis and autophagy, as well as the expression of SNHG5. SNHG5 directly regulated the expression of miR-20a. GC cells transfected with pcDNA-SNHG5 significantly promoted cell apoptosis and autophagy, while the co-transfected with miR-20a mimic dramatically reversed the effects of pcDNA-SNHG5. Overexpressed METase significantly promoted cell autophagy, which was abolished by down-regulated SNHG5.

CONCLUSION

Overexpressed METase promoted cell apoptosis and autophagy via up-regulating the expression of SNHG5 and down-regulating miR-20a in GC.

Bioactive and Bioadhesive Catechol Conjugated Polymers for Tissue Regeneration

The effective treatment of chronic wounds constitutes one of the most common worldwide healthcare problem due to the presence of high levels of proteases, free radicals and exudates in the wound, which constantly activate the inflammatory system, avoiding tissue regeneration. In this study, we describe a multifunctional bioactive and resorbable membrane with in-built antioxidant agent catechol for the continuous quenching of free radicals as well as to control inflammatory response, helping to promote the wound-healing process. This natural polyphenol (catechol) is the key molecule responsible for the mechanism of adhesion of mussels providing also the functionalized polymer with bioadhesion in the moist environment of the human body. To reach that goal, synthesized statistical copolymers of N-vinylcaprolactam (V) and 2-hydroxyethyl methacrylate (H) have been conjugated with catechol bearing hydrocaffeic acid (HCA) molecules with high yields. The system has demonstrated good biocompatibility, a sustained antioxidant response, an anti-inflammatory effect, an ultraviolet (UV) screen, and bioadhesion to porcine skin, all of these been key features in the wound-healing process. Therefore, these novel mussel-inspired materials have an enormous potential for application and can act very positively, favoring and promoting the healing effect in chronic wounds.