Biotinylated PAMAM G3 dendrimer conjugated with celecoxib and/or Fmoc-l-Leucine and its cytotoxicity for normal and cancer human cell lines

Design of nanosystems for melanoma treatment

Melanoma is a prevalent and concerning form of skin cancer affecting millions of individuals worldwide. Unfortunately, traditional treatments can be invasive and painful, prompting the need for alternative therapies with improved efficacy and patient outcomes. Nanosystems offer a promising solution to these obstacles through the rational design of nanoparticles (NPs) which are structured into nanocomposite forms, offering efficient approaches to cancer treatment procedures. A range of NPs consisting of polymeric, metallic and metal oxide, carbon-based, and virus-like NPs have been studied for their potential in treating skin cancer. This review summarizes the latest developments in functional nanosystems aimed at enhancing melanoma treatment. The fundamentals of these nanosystems, including NPs and the creation of various functional nanosystem types, facilitating melanoma treatment are introduced. Then, the advances in the applications of functional nanosystems for melanoma treatment are summarized, outlining both their benefits and the challenges encountered in implementing nanosystem therapies.

Advances, limitations and perspectives in the use of celecoxib-loaded nanocarriers in therapeutics of cancer

Cancer is highlighted as a major global health challenge in the XXI century. The cyclooxygenase-2 (COX-2) enzyme rises as a widespread tumor progression marker. Celecoxib (CXB) is a selective COX-2 inhibitor used in adjuvant cancer therapy, but high concentrations are required in humans. In this sense, the development of nanocarriers has been proposed once they can improve the biopharmaceutical, pharmacokinetic and pharmacological properties of drugs. In this context, this article reviews the progress in the development of CXB-loaded nanocarriers over the past decade and their prospects. Recent advances in the field of CXB-loaded nanocarriers demonstrate the use of complex formulations and the increasing importance of in vivo studies. The types of CXB-loaded nanocarriers that have been developed are heterogeneous and based on polymers and lipids together or separately. It was found that the work on CXB-loaded nanocarriers is carried out using established techniques and raw materials, such as poly (lactic-co-glicolic acid), cholesterol, phospholipids and poly(ethyleneglycol). The main improvements that have been achieved are the use of cell surface ligands, the simultaneous delivery of different synergistic agents, and the presence of materials that can provide imaging properties and other advanced features. The combination of CXB with other anti-inflammatory drugs and/or apoptosis inducers appears to hold effective pharmacological promise. The greatest advance to date from a clinical perspective is the ability of CXB to enhance the cytotoxic effects of established chemotherapeutic agents.

Application of nanoparticles in breast cancer treatment: a systematic review

It is estimated that cancer is the second leading cause of death worldwide. The primary or secondary cause of cancer-related mortality for women is breast cancer. The main treatment method for different types of cancer is chemotherapy with drugs. Because of less water solubility of chemotherapy drugs or their inability to pass through membranes, their body absorbs them inadequately, which lowers the treatment's effectiveness. Drug specificity and pharmacokinetics can be changed by nanotechnology using nanoparticles. Instead, targeted drug delivery allows medications to be delivered to the targeted sites. In this review, we focused on nanoparticles as carriers in targeted drug delivery, their characteristics, structure, and the previous studies related to breast cancer. It was shown that nanoparticles could reduce the negative effects of chemotherapy drugs while increasing their effectiveness. Lipid-based nanocarriers demonstrated notable results in this instance, and some products that are undergoing various stages of clinical trials are among the examples. Nanoparticles based on metal or polymers demonstrated a comparable level of efficacy. With the number of cancer cases rising globally, many researchers are now looking into novel treatment approaches, particularly the use of nanotechnology and nanoparticles in the treatment of cancer. In order to help clinicians, this article aimed to gather more information about various areas of nanoparticle application in breast cancer therapy, such as modifying their synthesis and physicochemical characterization. It also sought to gain a deeper understanding of the mechanisms underlying the interactions between nanoparticles and biologically normal or infected tissues.

Fluorinated PAMAM-Arginine Carrier Prodrugs for pH-Sensitive Sustained Ibuprofen Delivery

OBJECTIVE

The development of an efficient, multifunctional drug delivery system overcoming different obstacles generally associated with drug formulations, including the poor accumulation of the active principle in the target site and its sustained release for prolonged time.

METHODS

Our study proposes the development of a fluorinated poly(amidoamine) (PAMAM) carrier prodrug combining drug release boosted in alkaline environments with a possible implementation in 19F MRI applications. In particular, we functionalized the terminal primary amines of PAMAM G2 and G4 through an ad hoc designed fluorinated ibuprofen-arginine Michael acceptor to obtain multifunctional ibuprofen-PAMAM-Arg conjugates.

RESULTS

These carriers demonstrated pH-dependent and sustained ibuprofen release for more than 5 days. This advantage was observed in both weak alkaline and physiological buffer solutions, allowing to overcome the limits associated to the burst release from similar fluorinated Arg-PAMAM dendrimers with ibuprofen physically encapsulated.

CONCLUSION

These findings, coupled to the high biocompatibility of the system, suggest a potential synergistic biomedical application of our conjugates, serving as vehicles for drug delivery and as 19F magnetic resonance imaging contrast agents.

Skin cancer: understanding the journey of transformation from conventional to advanced treatment approaches

Skin cancer is a global threat to the healthcare system and is estimated to incline tremendously in the next 20 years, if not diagnosed at an early stage. Even though it is curable at an early stage, novel drug identification, clinical success, and drug resistance is another major challenge. To bridge the gap and bring effective treatment, it is important to understand the etiology of skin carcinoma, the mechanism of cell proliferation, factors affecting cell growth, and the mechanism of drug resistance. The current article focusses on understanding the structural diversity of skin cancers, treatments available till date including phytocompounds, chemotherapy, radiotherapy, photothermal therapy, surgery, combination therapy, molecular targets associated with cancer growth and metastasis, and special emphasis on nanotechnology-based approaches for downregulating the deleterious disease. A detailed analysis with respect to types of nanoparticles and their scope in overcoming multidrug resistance as well as associated clinical trials has been discussed.

Advancements in nanoparticle-based treatment approaches for skin cancer therapy

Skin cancer has emerged as the fifth most commonly reported cancer in the world, causing a burden on global health and the economy. The enormously rising environmental changes, industrialization, and genetic modification have further exacerbated skin cancer statistics. Current treatment modalities such as surgery, radiotherapy, conventional chemotherapy, targeted therapy, and immunotherapy are facing several issues related to cost, toxicity, and bioavailability thereby leading to declined anti-skin cancer therapeutic efficacy and poor patient compliance. In the context of overcoming this limitation, several nanotechnological advancements have been witnessed so far. Among various nanomaterials, nanoparticles have endowed exorbitant advantages by acting as both therapeutic agents and drug carriers for the remarkable treatment of skin cancer. The small size and large surface area to volume ratio of nanoparticles escalate the skin tumor uptake through their leaky vasculature resulting in enhanced therapeutic efficacy. In this context, the present review provides up to date information about different types and pathology of skin cancer, followed by their current treatment modalities and associated drawbacks. Furthermore, it meticulously discusses the role of numerous inorganic, polymer, and lipid-based nanoparticles in skin cancer therapy with subsequent descriptions of their patents and clinical trials.

A Review on Increasing the Targeting of PAMAM as Carriers in Glioma Therapy

Glioma is an invasive brain cancer, and it is difficult to achieve desired therapeutic effects due to the high postoperative recurrence rate and limited efficacy of drug therapy hindered by the biological barrier of brain tissue. Nanodrug delivery systems are of great interest, and many efforts have been made to utilize them for glioma treatment. Polyamidoamine (PAMAM), a starburst dendrimer, provides malleable molecular size, functionalized molecular structure and penetrable brain barrier characteristics. Therefore, PAMAM-based nanodrug delivery systems (PAMAM DDS) are preferred for glioma treatment research. In this review, experimental studies on PAMAM DDS for glioma therapy were focused on and summarized. Emphasis was given to three major topics: methods of drug loading, linkers between drug/ligand and PAMAM and ligands of modified PAMAM. A strategy for well-designed PAMAM DDS for glioma treatment was proposed. Purposefully understanding the physicochemical and structural characteristics of drugs is necessary for selecting drug loading methods and achieving high drug loading capacity. Additionally, functional ligands contribute to achieving the brain targeting, brain penetration and low toxicity of PAMAM DDS. Furthermore, a brilliant linker facilitates multidrug combination and multifunctional PAMAM DDS. PAMAM DDS show excellent promise as drug vehicles and will be further studied for product development and safety evaluation.

Peptide-Based Bioconjugates and Therapeutics for Targeted Anticancer Therapy

With rapidly growing knowledge in bioinformatics related to peptides and proteins, amino acid-based drug-design strategies have recently gained importance in pharmaceutics. In the past, peptide-based biomedicines were not widely used due to the associated severe physiological problems, such as low selectivity and rapid degradation in biological systems. However, various interesting peptide-based therapeutics combined with drug-delivery systems have recently emerged. Many of these candidates have been developed for anticancer therapy that requires precisely targeted effects and low toxicity. These research trends have become more diverse and complex owing to nanomedicine and antibody–drug conjugates (ADC), showing excellent therapeutic efficacy. Various newly developed peptide–drug conjugates (PDC), peptide-based nanoparticles, and prodrugs could represent a promising therapeutic strategy for patients. In this review, we provide valuable insights into rational drug design and development for future pharmaceutics.

Synthesis of Biotinylated PAMAM G3 Dendrimers Substituted with R-Glycidol and Celecoxib/Simvastatin as Repurposed Drugs and Evaluation of Their Increased Additive Cytotoxicity for Cancer Cell Lines

Simple Summary

New anti-cancer drugs can be created through the combination of well-known substances acting on different molecular targets. Repurposed drugs selected in this way can then be attached to special carriers that have specific, high affinity for cancer cells. In this study, two anti-glioma drugs, celecoxib and simvastatin, were chosen and linked to the PAMAM G3 dendrimer targeted to cancer cells by attached biotin and R-glycidol. In vitro studies performed with human glioblastoma (U-118 MG) and squamous cell carcinoma (SCC-15) cells revealed that dendrimer conjugate containing both celecoxib and simvastatin was 20–50 times more potent than either drug administered alone or in combination. Thus, the obtained combined conjugate can be considered as a potential candidate for a new therapy of malignant glioblastoma.

Abstract

Recent achievement in anticancer therapy considers the application of repurposed drugs in optimal combinations with the use of specific carriers for their targeted delivery. As a result, new optimized medications with reduced side effects can be obtained. In this study, two known anticancer drugs, celecoxib and/or simvastatin, were conjugated covalently with PAMAM G3 dendrimer and tested in vitro against human squamous carcinoma (SCC-15-15) and glioblastoma (U-118 MG) cells, as well as normal human fibroblasts (BJ). The obtained conjugates were also substituted with biotin and R-glycidol to increase their affinity for cancer cells and were characterized with NMR spectroscopy and dynamic light scattering technique. Conjugates furnished with two celecoxib and four simvastatin residues revealed the very high effectiveness and dramatically decreased the SCC-15 and U-118 MG cell viability at very low concentrations with IC₅₀ equal to about 3 µM. Its action was 20–50-fold stronger than that of either drug alone or as a mixture. Combined conjugate revealed also additive action since it was 2–8-fold more effective than conjugates with either single drug. The combined conjugate revealed rather low specificity since it was also highly cytotoxic for BJ cells. Despite this, it may be concluded that biotinylated and R-glycidylated PAMAM G3 dendrimers substituted with both celecoxib and simvastatin can be considered as a new perspective anticancer agent, effective in therapy of malignant, incurable glioblastomas.

Smart poly(amidoamine) dendron-functionalized magnetic graphene oxide for cancer therapy

A novel multicomponent magnetic nanocomposite whose drug release behavior is pH and temperature dependent.

A comprehensive review on immuno-nanomedicine for breast cancer therapy: Technical challenges and troubleshooting measures

Nanosized drug carriers have received a major attention in cancer therapeutics and theranostics. The immuno-nanomedicine is a combination of monoclonal antibody (mAb)/mAb-drug-nanoparticles. The immuno-nanomedicine offers a promising strategy to target cancer cells. However, the understating of nanotechnology, cancer biology, immunomedicine, and nanoparticle surface chemistry has provided a better clue to prepare the effective immuno-nanomedicine for cancer therapy. Moreover, the selection of nanoparticles type and its composition is essential for development of efficient drug delivery system (DDS) to target the cancer cell site. Immuno-nanomedicine works in the ligand-receptor binding mechanism through the interaction of mAb conjugated nanoparticles and specific antigen over expressed on target cancer cells. Therefore, the selection of specific receptors in the cancer cell and their ligand is important to prepare the active immuno-nanomedicines. Moreover, the factors such as drug loading, entrapment efficiency, size, shape, and ligand conjugation of a nanocarrier are considered as major factors for a better cancer cell, internalization, drug release, and cancer cell ablation. The target-based over-expression of antigen, mAb is engineered and conjugated with nanoparticles for successful targeting of the cancer cells without causing adverse effects to normal cells. Therefore, this review analyzed the fundamental factors in the immuno-nanomedicine for breast cancer and its technical challenges in the fabrication of the antibody alone/and drug conjugated nanoparticles.

Biotin Transport-Targeting Polysaccharide-Modified PAMAM G3 Dendrimer as System Delivering α-Mangostin into Cancer Cells and C. elegans Worms

The natural xanthone α-mangostin (αM) exhibits a wide range of pharmacological activities, including antineoplastic and anti-nematode properties, but low water solubility and poor selectivity of the drug prevent its potential clinical use. Therefore, the targeted third-generation poly(amidoamine) dendrimer (PAMAM G3) delivery system was proposed, based on hyperbranched polymer showing good solubility, high biocompatibility and low immunogenicity. A multifunctional nanocarrier was prepared by attaching αM to the surface amine groups of dendrimer via amide bond in the ratio 5 (G3^2B12gh5M) or 17 (G3^2B10gh17M) residues per one dendrimer molecule. Twelve or ten remaining amine groups were modified by conjugation with D-glucoheptono-1,4-lactone (gh) to block the amine groups, and two biotin (B) residues as targeting moieties. The biological activity of the obtained conjugates was studied in vitro on glioma U-118 MG and squamous cell carcinoma SCC-15 cancer cells compared to normal fibroblasts (BJ), and in vivo on a model organism Caenorhabditis elegans. Dendrimer vehicle G3^2B12gh at concentrations up to 20 µM showed no anti-proliferative effect against tested cell lines, with a feeble cytotoxicity of the highest concentration seen only with SCC-15 cells. The attachment of αM to the vehicle significantly increased cytotoxic effect of the drug, even by 4- and 25-fold for G3^2B12gh5M and G3^2B10gh17M, respectively. A stronger inhibition of cells viability and influence on other metabolic parameters (proliferation, adhesion, ATP level and Caspase-3/7 activity) was observed for G3^2B10gh17M than for G3^2B12gh5M. Both bioconjugates were internalized efficiently into the cells. Similarly, the attachment of αM to the dendrimer vehicle increased its toxicity for C. elegans. Thus, the proposed α-mangostin delivery system allowed the drug to be more effective in the dendrimer-bound as compared to free state against both cultured the cancer cells and model organism, suggesting that this treatment is promising for anticancer as well as anti-nematode chemotherapy.

The Therapeutic Efficacy of Dendrimer and Micelle Formulations for Breast Cancer Treatment

Breast cancer is among the most common types of cancer in women and it is the cause of a high rate of mortality globally. The use of anticancer drugs is the standard treatment approach used for this type of cancer. However, most of these drugs are limited by multi-drug resistance, drug toxicity, poor drug bioavailability, low water solubility, poor pharmacokinetics, etc. To overcome multi-drug resistance, combinations of two or more anticancer drugs are used. However, the combination of two or more anticancer drugs produce toxic side effects. Micelles and dendrimers are promising drug delivery systems that can overcome the limitations associated with the currently used anticancer drugs. They have the capability to overcome drug resistance, reduce drug toxicity, improve the drug solubility and bioavailability. Different classes of anticancer drugs have been loaded into micelles and dendrimers, resulting in targeted drug delivery, sustained drug release mechanism, increased cellular uptake, reduced toxic side effects of the loaded drugs with enhanced anticancer activity in vitro and in vivo. This review article reports the biological outcomes of dendrimers and micelles loaded with different known anticancer agents on breast cancer in vitro and in vivo.

Transporter-Targeted Nano-Sized Vehicles for Enhanced and Site-Specific Drug Delivery

Nano-devices are recognized as increasingly attractive to deliver therapeutics to target cells. The specificity of this approach can be improved by modifying the surface of the delivery vehicles such that they are recognized by the target cells. In the past, cell-surface receptors were exploited for this purpose, but plasma membrane transporters also hold similar potential. Selective transporters are often highly expressed in biological barriers (e.g., intestinal barrier, blood-brain barrier, and blood-retinal barrier) in a site-specific manner, and play a key role in the vectorial transfer of nutrients. Similarly, selective transporters are also overexpressed in the plasma membrane of specific cell types under pathological states to meet the biological needs demanded by such conditions. Nano-drug delivery systems could be strategically modified to make them recognizable by these transporters to enhance the transfer of drugs across the biological barriers or to selectively expose specific cell types to therapeutic drugs. Here, we provide a comprehensive review and detailed evaluation of the recent advances in the field of transporter-targeted nano-drug delivery systems. We specifically focus on areas related to intestinal absorption, transfer across blood-brain barrier, tumor-cell selective targeting, ocular drug delivery, identification of the transporters appropriate for this purpose, and details of the rationale for the approach.

Dendrimers as Modulators of Brain Cells

Nanostructured hyperbranched macromolecules have been extensively studied at the chemical, physical and morphological levels. The cellular structural and functional complexity of neural cells and their cross-talk have made it rather difficult to evaluate dendrimer effects in a mixed population of glial cells and neurons. Thus, we are at a relatively early stage of bench-to-bedside translation, and this is due mainly to the lack of data valuable for clinical investigations. It is only recently that techniques have become available that allow for analyses of biological processes inside the living cells, at the nanoscale, in real time. This review summarizes the essential properties of neural cells and dendrimers, and provides a cross-section of biological, pre-clinical and early clinical studies, where dendrimers were used as nanocarriers. It also highlights some examples of biological studies employing dendritic polyglycerol sulfates and their effects on glia and neurons. It is the aim of this review to encourage young scientists to advance mechanistic and technological approaches in dendrimer research so that these extremely versatile and attractive nanostructures gain even greater recognition in translational medicine.

Celecoxib substituted biotinylated poly(amidoamine) G3 dendrimer as potential treatment for temozolomide resistant glioma therapy and anti-nematode agent

Glioblastoma multiforme (GBM) is a one of the most widely diagnosed and difficult to treat type of central nervous system tumors. Resection combined with radiotherapy and temozolomide (TMZ) chemotherapy prolongs patients' survival only for 12 - 15 months after diagnosis. Moreover, many patients develop TMZ resistance, thus important is search for a new therapy regimes including targeted drug delivery. Most types of GBM reveal increased expression of cyclooxygenase-2 (COX-2) and production of prostaglandin E2 (PGE₂), that are considered as valuable therapeutic target. In these studies, the anti-tumor properties of the selective COX-2 inhibitor celecoxib (CXB) and biotinylated third generation of the poly(amidoamine) dendrimer substituted with 31 CXB residues (G3BC31) on TMZ -resistant U-118 MG glioma cell line were examined and compared with the effect of TMZ alone including viability, proliferation, migration and apoptosis, as well as the cellular expression of COX-2, ATP level, and PGE₂ production. Confocal microscopy analysis with the fluorescently labeled G3BC31 analogue has shown that the compound was effectively accumulated in U-118 MG cells in time-dependent manner and its localization was confirmed in lysosomes but not nuclei. G3BC31 reveal much higher cytotoxicity for U-118 MG cells at relatively low concentrations in the range of 2-4 µM with compared to CBX alone, active at 50-100 µM. This was due to induction of apoptosis and inhibition of proliferation and migration. Observed effects were concomitant with reduction of PGE₂ production but independent of COX-2 expression. We suggest that investigated conjugate may be a promising candidate for therapy of TMZ-resistant glioblastoma multiforme, although applicable in local treatment, since our previous study of G3BC31 did not demonstrate selectivity against glioma cells compared to normal human fibroblasts. However, it has to be pointed that in our in vivo studies conducted with model organism, Caenorhabditis elegans indicated high anti-nematode activity of G3BC31 in comparison with CXB alone that confirms of usefulness of that organism for estimation of anti-cancer drug toxicity.

Cell death-inducing properties of selected dendrimers against different breast cancer and leukemia cell lines

Dendrimers represent an opportunity for targeted drug delivery into tumor cells. This is facilitated, for example, by loading of dendrimers with anticancer compounds. However, to assess the effects caused by such conjugates, knowledge of the cytotoxicity of the dendrimers themselves is necessary. The poly(amido amine)-derived dendrimers G₁ (Phe)₆ , G₁ (Dan)₃ , and G₂ were selected due to their different numbers of free amino groups and the poly(propylene imine) (PPI) dendrimer PPI-G₃ served as a reference. The compounds were evaluated for cell-death induction using breast cancer (MCF-7, MDA-MB-231) and leukemia (LAMA-84, K562, SD-1, SUP-B15) cell lines. The compounds exhibited concentration-dependent effects in the low micromolar range against the mammary carcinoma cells. A dependency on the generation, and particularly on the type of dendrimer, was deduced while the quantity of the free amino groups was subsidiary. G₂ revealed to be most cytotoxic, also against all tested leukemia cell lines. The cell line SD-1, however, was susceptible to all dendrimers. The mode of cell death was mainly determined by necrosis, especially at higher concentrations, while apoptosis played a subordinate role. The other dendrimers exerted no antimetabolic effects against LAMA-84, K562, and SUP-B15 cells. Therefore, these dendrimers are generally suitable as nontoxic drug carriers for leukemia cells.

Biotin-Decorated PAMAM G4.5 Dendrimer Nanoparticles to Enhance the Delivery, Anti-Proliferative, and Apoptotic Effects of Chemotherapeutic Drug in Cancer Cells

Biotin receptors are overexpressed by various types of solid cancer cells and play a significant role in tumor metabolism, growth, and metastasis. Thus, targeting the biotin receptors on tumor cells may enhance the efficiency and reduce the side-effects of chemotherapy. The aim of this study was to develop a biotin-coupled poly(amido)amine (PAMAM) (PG4.5) dendrimer nanoparticle to enhance the tumor-specific delivery and intracellular uptake of anticancer drugs via receptor-mediated endocytosis. We modified PG4.5 with diethylenetriamine (DETA) followed by biotin via an amide bond and characterized the resulting PG4.5-DETA-biotin nanoparticles by 1H NMR, FTIR, and Raman spectroscopy. Loading and releasing of gemcitabine (GEM) from PG4.5-DETA-biotin were evaluated by UV-Visible spectrophotometry. Cell viability and cellular uptake were examined by MTT assay and flow cytometry to assess the biocompatibility, cellular internalization efficiency and antiproliferative activity of PG4.5-DETA-biotin/GEM. Gemcitabine-loaded PG4.5-DETA-biotin nanoparticles were spherical with a particle size of 81.6 ± 6.08 nm and zeta potential of 0.47 ± 1.25 mV. Maximum drug-loading content and encapsulation efficiency were 10.84 ± 0.16% and 47.01 ± 0.71%, respectively. Nearly 60.54 ± 1.99% and 73.96 ± 1.14% of gemcitabine was released from PG4.5-DETA-biotin/GEM nanoparticles after 48 h at the acidic pH values of 6.5 and 5, respectively. Flow cytometry and fluorescence microscopy of cellular uptake results revealed PG4.5-DETA-biotin/GEM nanoparticles selectively targeted cancer cells in vitro. Cytotoxicity assays demonstrated gemcitabine-loaded PG4.5-DETA-biotin significantly reduced cell viability and induced apoptosis in HeLa cells. Thus, biotin-coupled PG4.5-DETA nanocarrier could provide an effective, targeted drug delivery system and selectively convey gemcitabine into tumor cells.

PAMAM Dendrimer Nanomolecules Utilized as Drug Delivery Systems for Potential Treatment of Glioblastoma: A Systematic Review

Glioblastoma (GB) is a grade IV astrocytoma that maintains a poor prognosis with respect to current treatment options. Despite major advancements in the fields of surgery and chemoradiotherapy over the last few decades, the life expectancy for someone with glioblastoma remains virtually unchanged and warrants a new approach for treatment. Poly(amidoamine) (PAMAM) dendrimers are a type of nanomolecule that ranges in size (between 1 and 100 nm) and shape and can offer a new viable solution for the treatment of intracranial tumors, including glioblastoma. Their ability to deliver a variety of therapeutic cargo and penetrate the blood-brain barrier (BBB), while preserving low cytotoxicity, make them a favorable candidate for further investigation into the treatment of glioblastoma. Here, we present a systematic review of the current advancements in PAMAM dendrimer technology, including the wide spectrum of dendrimer generations formulated, surface modifications, core modifications, and conjugations developed thus far to enhance tumor specificity and tumor penetration for treatment of glioblastoma. Furthermore, we highlight the extensive variety of therapeutics capable of delivery by PAMAM dendrimers for the treatment of glioblastoma, including cytokines, peptides, drugs, siRNAs, miRNAs, and organic polyphenols. While there have been prolific results stemming from aggressive research into the field of dendrimer technology, there remains a nearly inexhaustible amount of questions that remain unanswered. Nevertheless, this technology is rapidly developing and is nearing the cusp of use for aggressive tumor treatment. To that end, we further highlight future prospects in focus as researchers continue developing more optimal vehicles for the delivery of therapeutic cargo.

Biotinylated Phosphorus Dendrimers as Control Line in Nucleic Acid Lateral Flow Tests

Lateral flow assays (LFA) are an affordable, easy-to-use, qualitative rapid test for clinical diagnosis in nonlaboratory environments and low-resource facilities. The control line of these tests is very important to provide a valid result, confirming that the platform operates correctly. A clear, nondiffused line is desirable. The number of colored nanoparticles that reach the control line in a positive test can be very small, and they should all be trapped efficiently by the molecules adsorbed there. In this work, we proposed the use of robust biotinylated dendrimers of two different generations as signal amplifiers in control lines of LFA, able to react with streptavidin-modified gold nanoparticles. Besides the synthesis and characterization, the analytical performance as control lines will be studied, and their response will be compared with other commercially available biotinylated molecules. Finally, the utility of the dendrimer implemented in a NALF (Nucleic Acid Lateral Flow) strip was also demonstrated for detection of the amplicons obtained by double-tagging PCR (polymerase chain reaction) for the detection of E. coli as a model of foodborne pathogen.

Dendrimer nanoparticles for colorectal cancer applications

Cancer nanotechnology is a prolific field of research, where nanotools are employed to diagnose and treat cancer with unprecedented precision. Targeted drug delivery is fundamental for more efficient cancer treatments. For this, nanoparticles have been extensively used during the past few years in order to improve the specificity, selectivity and controlled release of drug delivery. It holds potential in minimizing systemic toxicity through the development of functionalized particles for targeted treatment. Among all the type of nanoparticles, dendrimers display several advantages, which make them ideal candidates for improved and targeted drug delivery in cancer research. Dendrimers can transport large amounts of drug into specific areas. In addition, they can be employed for monitoring the progress of the treatment process, with an unprecedented theranostic capability. Special emphasis is given to colorectal cancer and to the preferred employed strategies for producing drug-loaded/functionalized NPs for cancer therapy in the past few years.

The Effect of Biotinylated PAMAM G3 Dendrimers Conjugated with COX-2 Inhibitor (celecoxib) and PPARγ Agonist (Fmoc-L-Leucine) on Human Normal Fibroblasts, Immortalized Keratinocytes and Glioma Cells in Vitro

Glioblastoma multiforme (GBM) is the most malignant type of central nervous system tumor that is resistant to all currently used forms of therapy. Thus, more effective GBM treatment strategies are being investigated, including combined therapies with drugs that may cross the blood brain barrier (BBB). Another important issue considers the decrease of deleterious side effects of therapy. It has been shown that nanocarrier conjugates with biotin can penetrate BBB. In this study, biotinylated PAMAM G3 dendrimers substituted with the recognized anticancer agents cyclooxygenase-2 (COX-2) inhibitor celecoxib and peroxisome proliferator-activated receptor γ (PPARγ) agonist Fmoc-L-Leucine (G3-BCL) were tested in vitro on human cell lines with different p53 status: glioblastoma (U-118 MG), normal fibroblasts (BJ) and immortalized keratinocytes (HaCaT). G3-BCL penetrated efficiently into the lysosomal and mitochondrial compartments of U-118 MG cells and induced death of U-118 MG cells via apoptosis and inhibited proliferation and migration at low IC₅₀ = 1.25 µM concentration, considerably lower than either drug applied alone. Comparison of the effects of G3-BCL on expression of COX-2 and PPARγ protein and PGE₂ production of three different investigated cell line phenotypes revealed that the anti-glioma effect of the conjugate was realized by other mechanisms other than influencing PPAR-γ expression and regardless of p53 cell status, it was dependent on COX-2 protein level and high PGE₂ production. Similar G3-BCL cytotoxicity was seen in normal fibroblasts (IC₅₀ = 1.29 µM) and higher resistance in HaCaT cells (IC₅₀ = 4.49 µM). Thus, G3-BCL might be a good candidate for the targeted, local glioma therapy with limited site effects.

Mixed-Generation PAMAM G3-G0 Megamer as a Drug Delivery System for Nimesulide: Antitumor Activity of the Conjugate Against Human Squamous Carcinoma and Glioblastoma Cells

Polyhydroxylated dendrimer was synthesized from poly(amidoamine) (PAMAM) dendrimer generation 3 by addition of glycidol (G3^gl). G3^gl megamer was further modified by binding PAMAM G0 dendrimers by activation of G3^gl with p-nitrophenylchloroformate, followed by the addition of excess PAMAM G0 and purification using dialysis. The maximum G0 binding capacity of G3^gl was 12 in the case when G0 was equipped with two covalently attached nimesulide equivalents. Nimesulide (N) was converted into N-(p-nitrophenyl) carbonate derivative and fully characterized using X-ray crystallography and spectral methods. Nimesulide was then attached to G0 via a urea bond to yield G0^2N. The mixed generation G3^gl–G0^2N megamer was characterized using ¹H NMR spectroscopy, and its molecular weight was estimated to be 22.4 kDa. The AFM image of G3^gl–G0^2N deposited on mica demonstrated aggregation of nimesulide-covered megamer. The height of the deposited megamer was 8.5 nm. The megameric conjugate with nimesulide was tested in vitro on three human cell lines: squamous cell carcinoma (SCC-15) and glioblastoma (U-118 MG) overexpressing cyclooxygenase-2 (COX-2), and normal skin fibroblasts (BJ). The conjugate efficiently penetrated into all cells and was more cytotoxic against SCC-15 than against BJ. Moreover, the conjugate produced a strong and selective antiproliferative effect on both cancer cell lines (IC₅₀ < 7.5 µM).

Synthesis and Different Effects of Biotinylated PAMAM G3 Dendrimer Substituted with Nimesulide in Human Normal Fibroblasts and Squamous Carcinoma Cells

Squamous cell carcinoma (SCC) remains a main cause of mortality in patients with neck and head cancers, with poor prognosis and increased prevalence despite of available therapies. Recent studies have identified a role of cyclooxygenases, particularly inducible isoform cyclooxygenase-2 (COX-2) and its metabolite prostaglandin E2 (PGE₂) in cancer cell proliferation, and its inhibition become a target for control of cancer development, particularly in the view of recognized additive or synergic action of COX-2 inhibitors with other forms of therapy. Nimesulide (N), the selective COX-2 inhibitor, inhibits growth and proliferation of various types of cancer cells by COX-2 dependent and independent mechanisms. In the presented study, the conjugates of biotinylated third generation poly(amidoamine) dendrimer (PAMAM) with covalently linked 18 (G3^B18N) and 31 (G3^B31N) nimesulide residues were synthesized and characterized by NMR spectroscopy. Biological properties of conjugates were evaluated, including cytotoxicity, proliferation, and caspase 3/7 activities in relation to COX-2/PGE₂ axis signaling in human normal fibroblast (BJ) and squamous cell carcinoma (SCC-15). Both conjugates exerted a selective cytotoxicity against SCC-15 as compared with BJ cells at low 1.25-10 µM concentration range and their action in cancer cells was over 250-fold stronger than nimesulide alone. Conjugates overcome apoptosis resistance and sensitized SCC-15 cells to the apoptotic death independently of COX-2/PGE₂ axis. In normal human fibroblasts the same concentrations of G3^B31N conjugate were less effective in inhibition of proliferation and induction of apoptosis, as measured by caspase 3/7 activity in a manner depending on increase of PGE₂ production by either COX-1/COX-2.