Dual Therapeutic Action of a Neutralizing Anti-FGF2 Aptamer in Bone Disease and Bone Cancer Pain

Polyamines promote xenobiotic nucleic acid synthesis by modified thermophilic polymerase mutants

The enzymatic synthesis of xenobiotic nucleic acids (XNA), which are artificially sugar-modified nucleic acids, is essential for the preparation of XNA libraries. XNA libraries are used in the in vitro selection of XNA aptamers and enzymes (XNAzymes). Efficient enzymatic synthesis of various XNAs can enable the screening of high-quality XNA aptamers and XNAzymes by expanding the diversity of XNA libraries and adding a variety of properties to XNA aptamers and XNAzymes. However, XNAs that form unstable duplexes with DNA, such as arabino nucleic acid (ANA), may dissociate during enzyme synthesis at temperatures suitable for thermophilic polymerases. Thus, such XNAs are not efficiently synthesised by the thermophilic polymerase mutants at the end of the sequence. This undesirable bias reduces the possibility of generating high-quality XNA aptamers and XNAzymes. Here, we demonstrate that polyamine-induced DNA/ANA duplex stabilisation promotes ANA synthesis that is catalysed by thermophilic polymerase mutants. Several polyamines, including spermine, spermidine, cadaverine, and putrescine promote ANA synthesis. The negative effect of polyamines on the fidelity of ANA synthesis was negligible. We also showed that polyamines promote the synthesis of other XNAs, including 2'-amino-RNA/2'-fluoro-RNA mixture and 2'-O-methyl-RNA. In addition, we found that polyamine promotes DNA synthesis from the 2'-O-methyl-RNA template. Polyamines, with the use of thermophilic polymerase mutants, may allow further development of XNA aptamers and XNAzymes by promoting the transcription and reverse transcription of XNAs.

RaptGen-Assisted Generation of an RNA/DNA Hybrid Aptamer against SARS-CoV-2 Spike Protein

Optimization of aptamers in length and chemistry is crucial for industrial applications. Here, we developed aptamers against the SARS-CoV-2 spike protein and achieved optimization with a deep-learning-based algorithm, RaptGen. We conducted a primer-less SELEX against the receptor binding domain (RBD) of the spike with an RNA/DNA hybrid library, and the resulting sequences were subjected to RaptGen analysis. Based on the sequence profiling by RaptGen, a short truncation aptamer of 26 nucleotides was obtained and further optimized by a chemical modification of relevant nucleotides. The resulting aptamer is bound to RBD not only of SARS-CoV-2 wildtype but also of its variants, SARS-CoV-1, and Middle East respiratory syndrome coronavirus (MERS-CoV). We concluded that the RaptGen-assisted discovery is efficient for developing optimized aptamers.

Safety and tolerability of intravitreal umedaptanib pegol (anti-FGF2) for neovascular age-related macular degeneration (nAMD): a phase 1, open-label study

OBJECTIVE

To evaluate the efficacy and safety of a single-dose intravitreal umedaptanib pegol (anti-FGF2, investigational new drug) for the treatment of neovascular age-related macular degeneration (nAMD).

METHODS

Nine participants who had a diagnosis of refractory nAMD were enrolled and received a single intravitreal injection of umedaptanib pegol at increasing doses of 0.2, 1.0 or 2.0 mg in the study eye.

RESULTS

All three doses of umedaptanib pegol evaluated in the study were safe and well tolerated. No severe adverse event (AE) was observed in the study. There was an improvement in retinal fluid measured by central subfield thickness (CST) in most subjects. Remarkably, all three subjects who received 2.0 mg/eye showed improvement of more than 150 μm.

CONCLUSIONS

Intravitreal umedaptanib pegol was safe, well tolerated, and demonstrated an indication of bioactivity in participants that have persistent subretinal fluid refractory to the treatment with anti-VEGFs.

Clinical proof of concept for anti-FGF2 therapy in exudative age-related macular degeneration (nAMD): phase 2 trials in treatment-naïve and anti-VEGF pretreated patients

BACKGROUND/OBJECTIVE

Intravitreal injections of anti-vascular endothelial growth factor (VEGF) agents are the first-line treatment for exudative age-related macular degeneration (nAMD). Due to the limitations of these standard therapies, targeting alternative mechanisms of action may be helpful for treatment of this very common disease. Here, we investigated an anti-fibroblast growth factor-2 (FGF2) aptamer, umedaptanib pegol, a next generation therapeutic for the treatment of nAMD.

METHODS

Three phase 2 studies were designed. First, a multicentre, randomized, double-masked TOFU study assessed the efficacy of intravitreal injections of umedaptanib pegol monotherapy or in combination with aflibercept, compared to aflibercept monotherapy in 86 subjects with anti-VEGF pretreated nAMD. Second, 22 subjects who had exited the TOFU study received 4 monthly intravitreal injections of umedaptanib pegol (extension, RAMEN study). Third, as an investigator-sponsored trial (TEMPURA study), a single-center, open-label, 4-month study was designed to evaluate the safety and treatment efficacy of umedaptanib pegol in five naïve nAMD patients who had not received any prior anti-VEGF treatment.

RESULTS

The TOFU study demonstrated that umedaptanib pegol alone or in combination with aflibercept did not improve best-corrected visual acuity (BCVA) and central subfield thickness (CST) over aflibercept alone. However, the change in BCVA and CST at primary endpoint was marginal in all the three treatment groups, suggesting that umedaptanib pegol is effective to prevent the disease progression. The RAMEN study confirmed the cessation of disease progression. In the TEMPURA study, naïve nAMD patients showed improvement and no further macular degeneration, with striking improvement of visual acuity and central subfield thickness in some of the patients.

CONCLUSIONS

These results demonstrate, for the first time, clinical proof of concept for aptamer based anti-FGF2 therapy of nAMD.

Aptamer Technologies in Neuroscience, Neuro-Diagnostics and Neuro-Medicine Development

Aptamers developed using in vitro Systematic Evolution of Ligands by Exponential Enrichment (SELEX) technology are single-stranded nucleic acids 10-100 nucleotides in length. Their targets, often with specificity and high affinity, range from ions and small molecules to proteins and other biological molecules as well as larger systems, including cells, tissues, and animals. Aptamers often rival conventional antibodies with improved performance, due to aptamers' unique biophysical and biochemical properties, including small size, synthetic accessibility, facile modification, low production cost, and low immunogenicity. Therefore, there is sustained interest in engineering and adapting aptamers for many applications, including diagnostics and therapeutics. Recently, aptamers have shown promise as early diagnostic biomarkers and in precision medicine for neurodegenerative and neurological diseases. Here, we critically review neuro-targeting aptamers and their potential applications in neuroscience research, neuro-diagnostics, and neuro-medicine. We also discuss challenges that must be overcome, including delivery across the blood-brain barrier, increased affinity, and improved in vivo stability and in vivo pharmacokinetic properties.

Cell unit-inspired natural nano-based biomaterials as versatile building blocks for bone/cartilage regeneration

The regeneration of weight-bearing bone defects and critical-sized cartilage defects remains a significant challenge. A wide range of nano-biomaterials are available for the treatment of bone/cartilage defects. However, their poor compatibility and biodegradability pose challenges to the practical applications of these nano-based biomaterials. Natural biomaterials inspired by the cell units (e.g., nucleic acids and proteins), have gained increasing attention in recent decades due to their versatile functionality, compatibility, biodegradability, and great potential for modification, combination, and hybridization. In the field of bone/cartilage regeneration, natural nano-based biomaterials have presented an unparalleled role in providing optimal cues and microenvironments for cell growth and differentiation. In this review, we systematically summarize the versatile building blocks inspired by the cell unit used as natural nano-based biomaterials in bone/cartilage regeneration, including nucleic acids, proteins, carbohydrates, lipids, and membranes. In addition, the opportunities and challenges of natural nano-based biomaterials for the future use of bone/cartilage regeneration are discussed.

Discovery of Aptamers and the Acceleration of the Development of Targeting Research in Ophthalmology

Aptamers are widely applied to diagnosis and therapy because of their targeting. However, the current progress of research into aptamers for the treatment of eye disorders has not been well-documented. The current literature on aptamers was reviewed in this study. Aptamer-related drugs and biochemical sensors have been evaluated for several eye disorders within the past decade; S58 targeting TGF-β receptor II and pegaptanib targeting vascular endothelial growth factor (VEGF) are used to prevent fibrosis after glaucoma filtration surgery. Anti-brain-derived neurotrophic factor aptamer has been used to diagnose glaucoma. The first approved aptamer drug (pegaptanib) has been used to inhibit angiogenesis in age-related macular degeneration (AMD) and diabetic retinopathy (DR), and its efficacy and safety have been demonstrated in clinical trials. Aptamers, including E10030, RBM-007, AS1411, and avacincaptad pegol, targeting other angiogenesis-related biomarkers have also been discovered and subjected to clinical trials. Aptamers, such as C promoter binding factor 1, CD44, and advanced end products in AMD and DR, targeting other signal pathway proteins have also been discovered for therapy, and biochemical sensors for early diagnosis have been developed based on aptamers targeting VEGF, connective tissue growth factor, and lipocalin 1. Aptamers used for early detection and treatment of ocular tumors were derived from other disease biomarkers, such as CD71, nucleolin, and high mobility group A. In this review, the development and application of aptamers in eye disorders in recent years are systematically discussed, which may inspire a new link between aptamers and eye disorders. The aptamer development trajectory also facilitates the discovery of the pathogenesis and therapeutic strategies for various eye disorders.

Aptamer Technology and Its Applications in Bone Diseases

Aptamers are single-stranded nucleic acids (DNA, short RNA, or other artificial molecules) produced by the Systematic Evolution of Ligands by Exponential Enrichment (SELEX) technology, which can be tightly and specifically combined with desired targets. As a comparable alternative to antibodies, aptamers have many advantages over traditional antibodies such as a strong chemical stability and rapid bulk production. In addition, aptamers can bind targets in various ways, and are not limited like the antigen-antibody combination. Studies have shown that aptamers have tremendous potential to diagnose and treat clinical diseases. However, only a few aptamer-based drugs have been used because of limitations of the aptamers and SELEX technology. To promote the development and applications of aptamers, we present a review of the methods optimizing the SELEX technology and modifying aptamers to boost the selection success rate and improve aptamer characteristics. In addition, we review the application of aptamers to treat bone diseases.

From Initiation to Maintenance: HIV-1 Gp120-induced Neuropathic Pain Exhibits Different Molecular Mechanisms in the Mouse Spinal Cord Via Bioinformatics Analysis Based on RNA Sequencing

Human immunodeficiency virus (HIV), which causes acquired immunodeficiency syndrome (AIDS), remains one of the most diverse crucial health and development challenges around the world. People infected with HIV constitute a large patient population, and a significant number of them experience neuropathic pain. To study the key mechanisms that mediate HIV-induced neuropathic pain (HNP), we established an HNP mouse model via intrathecal injection of the HIV-1 envelope glycoprotein gp120. The L3~L5 spinal cord was isolated on postoperative days 1/12 (POD1/12), 1 (POD1), and 14 (POD14) for RNA sequencing to investigate the gene expression profiles of the initiation, transition, and maintenance stages of HNP. A total of 1682, 430, and 413 differentially expressed genes were obtained in POD1/12, POD1, and POD14, respectively, and their similarity was low. Bioinformatics analysis confirmed that POD1/12, POD1, and POD14 exhibited different biological processes and signaling pathways. Inflammation, oxidative damage, apoptosis, and inflammation-related signaling pathways were enriched on POD1/12. Inflammation, chemokine activity, and downstream signaling regulated by proinflammatory cytokines, such as the MTOR signaling pathway, were enriched on POD1, while downregulation of ion channel activity, mitochondrial damage, endocytosis, MAPK and neurotrophic signaling pathways developed on POD14. Additionally, we screened key genes and candidate genes, which were verified at the transcriptional and translational levels. Our results suggest that the initiation and maintenance of HNP are regulated by different molecular mechanisms. Therefore, our research may yield a fresh and deeper understanding of the mechanisms underlying HNP, providing accurate molecular targets for HNP therapy.

New developments in the biology of fibroblast growth factors

The fibroblast growth factor (FGF) family is composed of 18 secreted signaling proteins consisting of canonical FGFs and endocrine FGFs that activate four receptor tyrosine kinases (FGFRs 1-4) and four intracellular proteins (intracellular FGFs or iFGFs) that primarily function to regulate the activity of voltage-gated sodium channels and other molecules. The canonical FGFs, endocrine FGFs, and iFGFs have been reviewed extensively by us and others. In this review, we briefly summarize past reviews and then focus on new developments in the FGF field since our last review in 2015. Some of the highlights in the past 6 years include the use of optogenetic tools, viral vectors, and inducible transgenes to experimentally modulate FGF signaling, the clinical use of small molecule FGFR inhibitors, an expanded understanding of endocrine FGF signaling, functions for FGF signaling in stem cell pluripotency and differentiation, roles for FGF signaling in tissue homeostasis and regeneration, a continuing elaboration of mechanisms of FGF signaling in development, and an expanding appreciation of roles for FGF signaling in neuropsychiatric diseases. This article is categorized under: Cardiovascular Diseases > Molecular and Cellular Physiology Neurological Diseases > Molecular and Cellular Physiology Congenital Diseases > Stem Cells and Development Cancer > Stem Cells and Development.

Neuropathogenicity of non-viable Borrelia burgdorferi ex vivo

Even after appropriate treatment, a proportion of Lyme disease patients suffer from a constellation of symptoms, collectively called Post-Treatment Lyme Disease Syndrome (PTLDS). Brain PET scan of patients with PTLDS have demonstrated likely glial activation indicating persistent neuroinflammatory processes. It is possible that unresolved bacterial remnants can continue to cause neuroinflammation. In previous studies, we have shown that non-viable Borrelia burgdorferi can induce neuroinflammation and apoptosis in an oligodendrocyte cell line. In this follow-up study, we analyze the effect of sonicated remnants of B. burgdorferi on primary rhesus frontal cortex (FC) and dorsal root ganglion (DRG) explants. Five FC and three DRG tissue fragments from rhesus macaques were exposed to sonicated B. burgdorferi and analyzed for 26 inflammatory mediators. Live bacteria and medium alone served as positive and negative control, respectively. Tissues were also analyzed for cell types mediating inflammation and overall apoptotic changes. Non-viable B. burgdorferi induced significant levels of several inflammatory mediators in both FC and DRG, similar to live bacteria. However, the levels induced by non-viable B. burgdorferi was often (several fold) higher than those induced by live ones, especially for IL-6, CXCL8 and CCL2. This effect was also more profound in the FC than in the DRG. Although the levels often differed, both live and dead fragments induced the same mediators, with significant overlap between FC and DRG. In the FC, immunohistochemical staining for several inflammatory mediators showed the presence of multiple mediators in astrocytes, followed by microglia and oligodendrocytes, in response to bacterial remnants. Staining was also seen in endothelial cells. In the DRG, chemokine/cytokine staining was predominantly seen in S100 positive (glial) cells. B. burgdorferi remnants also induced significant levels of apoptosis in both the FC and DRG. Apoptosis was confined to S100 + cells in the DRG while distinct neuronal apoptosis was also detected in most FC tissues in response to sonicated bacteria. Non-viable B. burgdorferi can continue to be neuropathogenic to both CNS and PNS tissues with effects likely more profound in the former. Persistence of remnant-induced neuroinflammatory processes can lead to long term health consequences.

Emerging therapies for Achondroplasia: changing the rules of the game

INTRODUCTION

Achondroplasia is the most common genetic cause of disproportionate short stature, affecting over 360,000 individuals. Serious complications contributing to significant morbidity in affected individuals include cranio-cervical junction compression and obstructive sleep apnoea. Current clinically available treatments are predominantly symptomatic, and associated with variable outcomes. We summarise the new precision investigational products that are currently in Phase 2 and Phase 3 clinical trials for the treatment of individuals with achondroplasia.

AREAS COVERED

Fibroblast growth factor receptor 3 (FGFR3), a membrane-spanning tyrosine kinase receptor, binds various fibroblast growth factors (FGF) to regulate the normal process of endochondral bone growth. Gain of FGFR3 function in individuals with achondroplasia results in inhibition of normal endochondral ossification. A greater understanding of these molecular pathways through animal models has led to the development of several targeted therapies being tested in children, which we discuss in this review.

EXPERT OPINION

The last decade has been game-changing in terms of new precision therapies for children with achondroplasia that have the potential to fundamentally change the natural history of this condition. The next decade will see how these therapies compare, if they might be used in combination, and evaluate the balance of their long-term benefits and harms.

Evaluating the results of long tubular bone distraction with an advanced rod monolateral external fixator for achondroplasia

The work aimed to evaluate the effectiveness of the developed distraction system based on the rod external monolateral fixation mechanisms by comparing it with the classical technique of long tubular bones distraction based on the circular multi-axial system. The study included patients with a genetically confirmed diagnosis of achondroplasia. The experimental group consisted of 14 patients who underwent surgical limb lengthening by the rod monolateral external fixator with a distraction system developed by the authors. The lengthening was performed on 28 segments of tubular bones. The majority of the experimental group patients achieved the lengthening value close to the planned one and the deformation correction. The fixation period was averagely 83.8 ± 3.7 days, the regenerate length was 8.5 ± 0.6 cm, and the mechanical strength of the distraction regenerate was 10.3° ± 2.18°. The rod external fixator with a control distraction system developed by the authors has small dimensions and low weight of the external supporting elements of high durability. It is reported to provide a good psychological tolerance of the treatment process and significantly outperforms the circular multi-axis system. Considering the aforementioned, the proposed apparatus can grant good orthopedic care to patients with achondroplasia.

An RNA aptamer restores defective bone growth in FGFR3-related skeletal dysplasia in mice

Achondroplasia is the most prevalent genetic form of dwarfism in humans and is caused by activating mutations in FGFR3 tyrosine kinase. The clinical need for a safe and effective inhibitor of FGFR3 is unmet, leaving achondroplasia currently incurable. Here, we evaluated RBM-007, an RNA aptamer previously developed to neutralize the FGFR3 ligand FGF2, for its activity against FGFR3. In cultured rat chondrocytes or mouse embryonal tibia organ culture, RBM-007 rescued the proliferation arrest, degradation of cartilaginous extracellular matrix, premature senescence, and impaired hypertrophic differentiation induced by FGFR3 signaling. In cartilage xenografts derived from induced pluripotent stem cells from individuals with achondroplasia, RBM-007 rescued impaired chondrocyte differentiation and maturation. When delivered by subcutaneous injection, RBM-007 restored defective skeletal growth in a mouse model of achondroplasia. We thus demonstrate a ligand-trap concept of targeting the cartilage FGFR3 and delineate a potential therapeutic approach for achondroplasia and other FGFR3-related skeletal dysplasias.

Multiple Therapeutic Applications of RBM-007, an Anti-FGF2 Aptamer

Vascular endothelial growth factor (VEGF) plays a pivotal role in angiogenesis, but is not the only player with an angiogenic function. Fibroblast growth factor-2 (FGF2), which was discovered before VEGF, is also an angiogenic growth factor. It has been shown that FGF2 plays positive pathophysiological roles in tissue remodeling, bone health, and regeneration, such as the repair of neuronal damage, skin wound healing, joint protection, and the control of hypertension. Targeting FGF2 as a therapeutic tool in disease treatment through clinically useful inhibitors has not been developed until recently. An isolated inhibitory RNA aptamer against FGF2, named RBM-007, has followed an extensive preclinical study, with two clinical trials in phase 2 and phase 1, respectively, underway to assess the therapeutic impact in age-related macular degeneration (wet AMD) and achondroplasia (ACH), respectively. Moreover, showing broad therapeutic potential, preclinical evidence supports the use of RBM-007 in the treatment of lung cancer and cancer pain.

Advantages and Disadvantages of Different Treatment Methods in Achondroplasia: A Review

Achondroplasia (ACH) is a disease caused by a missense mutation in the FGFR3 (fibroblast growth factor receptor 3) gene, which is the most common cause of short stature in humans. The treatment of ACH is necessary and urgent because untreated achondroplasia has many complications, both orthopedic and neurological, which ultimately lead to disability. This review presents the current and potential pharmacological treatments for achondroplasia, highlighting the advantages and disadvantages of all the drugs that have been demonstrated in human and animal studies in different stages of clinical trials. The article includes the potential impacts of drugs on achondroplasia symptoms other than short stature, including their effects on spinal canal stenosis, the narrowing of the foramen magnum and the proportionality of body structure. Addressing these effects could significantly improve the quality of life of patients, possibly reducing the frequency and necessity of hospitalization and painful surgical procedures, which are currently the only therapeutic options used. The criteria for a good drug for achondroplasia are best met by recombinant human growth hormone at present and will potentially be met by vosoritide in the future, while the rest of the drugs are in the early stages of clinical trials.

Recent Progress and Opportunities for Nucleic Acid Aptamers

Coined three decades ago, the term aptamer and directed evolution have now reached their maturity. The concept that nucleic acid could modulate the activity of target protein as ligand emerged from basic science studies of viruses. Aptamers are short nucleic acid sequences capable of specific, high-affinity molecular binding, which allow for therapeutic and diagnostic applications. Compared to traditional antibodies, aptamers have several advantages, including small size, flexible structure, good biocompatibility, and low immunogenicity. In vitro selection method is used to isolate aptamers that are specific for a desired target from a randomized oligonucleotide library. The first aptamer drug, Macugen, was approved by FDA in 2004, which was accompanied by many studies and clinical investigations on various targets and diseases. Despite much promise, most aptamers have failed to meet the requisite safety and efficacy standards in human clinical trials. Amid these setbacks, the emergence of novel technologies and recent advances in aptamer and systematic evolution of ligands by exponential enrichment (SELEX) design are fueling hope in this field. The unique properties of aptamer are gaining renewed interest in an era of COVID-19. The binding performance of an aptamer and reproducibility are still the key issues in tackling current hurdles in clinical translation. A thorough analysis of the aptamer binding under varying conditions and the conformational dynamics is warranted. Here, the challenges and opportunities of aptamers are reviewed with recent progress.

Specific inhibition of FGF5-induced cell proliferation by RNA aptamers

Fibroblast growth factor 5 (FGF5) is a crucial regulator of hair growth and an oncogenic factor in several human cancers. To generate FGF5 inhibitors, we performed Systematic Evolution of Ligands by EXponential enrichment and obtained novel RNA aptamers that have high affinity to human FGF5. These aptamers inhibited FGF5-induced cell proliferation, but did not inhibit FGF2-induced cell proliferation. Surface plasmon resonance demonstrated that one of the aptamers, F5f1, binds to FGF5 tightly (K_d = 0.7 ± 0.2 nM), but did not fully to FGF1, FGF2, FGF4, FGF6, or FGFR1. Based on sequence and secondary structure similarities of the aptamers, we generated the truncated aptamer, F5f1_56, which has higher affinity (K_d = 0.118 ± 0.003 nM) than the original F5f1. Since the aptamers have high affinity and specificity to FGF5 and inhibit FGF5-induced cell proliferation, they may be candidates for therapeutic use with FGF5-related diseases or hair disorders.

Novel therapeutic approaches for the treatment of achondroplasia

Achondroplasia is the most common form of human dwarfism. The molecular basis of achondroplasia was elucidated in 1994 with the identification of the fibroblast growth factor receptor 3 (FGFR3) as the causative gene. Missense mutations causing achondroplasia result in activation of FGFR3 and its downstream signaling pathways, disturbing chondrogenesis, osteogenesis, and long bone elongation. A more accurate understanding of the clinical and molecular aspects of achondroplasia has allowed new therapeutic approaches to be developed. These are based on: clear understanding of the natural history of the disease; proof-of-concept preclinical studies in mouse models; and the current state of knowledge regarding FGFR3 and related growth plate homeostatic pathways. This review provides a brief overview of the preclinical mouse models of achondroplasia that have led to new, non-surgical therapeutic strategies being assessed and applied to children with achondroplasia through pioneering clinical trials.

Clinical complexity of utilizing FGFR inhibitors in cancer therapeutics

INTRODUCTION

Fibroblast growth factor receptors (FGFR 1-4) are a highly conserved family of receptor tyrosine kinases, involved in several physiological processes. Genetic aberrations of FGFRs and their ligands, fibroblast growth factors (FGFs) are involved in several pathological processes including cancer. The FGF-FGFR axis has emerged as a treatment target in oncology. Because these aberrations drive cancer progression, the development of FGFR targeted therapies have been accelerated.

AREAS COVERED

In this comprehensive review, we evaluate molecular pathology and targeted therapies to FGFRs. We reviewed the evidence for safety and efficacy from preclinical and clinical studies (phase I-III) of FGFR targeted therapies. We also discuss potential challenges in bringing these targeted therapies from bench to bedside and the potential opportunities.

EXPERT OPINION

Despite the challenges of the clinical development of FGFR targeted therapies, two FGFR small-molecule inhibitors, namely Erdafitinib and Pemigatinib, are FDA approved for urothelial cancer and cholangiocarcinoma, respectively. Understanding and detection of FGFR genomic aberrations, protein overexpression and the development of isoform-specific inhibitors are factors in the clinical success of these therapies. An enhanced understanding of patient selection based on a gene signatures or biomarkers is key to success of FGFR targeted therapies.

Pharmacokinetics and safety after once and twice a day doses of meclizine hydrochloride administered to children with achondroplasia

Achondroplasia (ACH) is the most common short-limbed skeletal dysplasia caused by activating mutations in the fibroblast growth factor receptor 3 (FGFR3) gene. We identified that meclizine hydrochloride inhibited FGFR3 signaling in various chondrocytic cells and promoted longitudinal bone growth in mouse model of ACH. Meclizine has safely been used for more than 50 years, but it lacks the safety data for repeated administration and pharmacokinetics (PK) when administered to children. We performed a phase Ia study to evaluate the PK and safety of meclizine administered orally to ACH children. Twelve ACH children aged from 5 to younger than 11 years were recruited, and the first 6 subjects received once a day of meclizine in the fasted condition, subsequent 6 subjects received twice a day of meclizine in the fed condition. Meclizine was well tolerated in ACH children with no serious adverse events. The mean C_max, T_max, AUC_0-24h, t1/2 during 24 hours in the fasted condition were 130 ng/mL, 1.7 hours, 761 ng·h/mL, and 8.5 hours respectively. The simulation of repeated administration of meclizine for 14 days demonstrated that plasma concentration apparently reached steady state around 10 days after the first dose both at once a day and twice a day administration. The AUC_0-10h of the fasting and fed condition were 504 ng·h/mL and 813 ng·h/mL, respectively, indicating exposure of meclizine increased with the diet. Although higher drug exposure was confirmed in ACH children compared to adults, a single administration of meclizine seemed to be well tolerated.

Peripheral FGFR1 Regulates Myofascial Pain in Rats via the PI3K/AKT Pathway

Myofascial pain syndrome (MPS) is a type of skeletal pain identified by myofascial trigger points (MTrPs). The formation of MTrPs is linked to muscle damage. The fibroblast growth factor receptor (FGFR1) has been found to cause pain sensitivity while repairing tissue damage. The aim of the current study was to explore the mechanism of FGFR1 in MTrPs. We used a RayBio human phosphorylation array kit to measure p-FGFR1 levels in human control subjects and patients with MTrPs. P-FGFR1 was upregulated in the patients with MTrPs. Then a rat model of MPS was established by a blunt strike on the left gastrocnemius muscles (GM) and eccentric-exercise for 8 weeks with 4 weeks of recovery. After establishing the MPS model, the morphology of the GM changed, and the differently augmented sizes of round fibers (contracture knots) in the transverse section and fusiform shapes in the longitudinal section were clearly seen in the rats with myofascial pain. The expression of p-FGFR1 was upregulated on the peripheral nerves and dorsal root ganglion neurons in the MTrPs group. The spinal Fos protein expression was increased in the MTrPs group. Additionally, the mechanical pain threshold was reduced, and the expression of FGF2, p-FGFR1, PI3K-p110γ, and p-AKT increased in the MTrPs group. PD173074 increased the mechanical pain threshold of the MTrPs group, and inhibited the expression of p-FGFR1, PI3K-p110γ, and p-AKT. Moreover, LY294002 increased the mechanical pain threshold of the MTrPs group. These findings suggest that FGFR1 may regulate myofascial pain in rats through the PI3K/AKT pathway.

New developments in the management of achondroplasia

Achondroplasia is the most common form of disproportionate short stature. A dominantly inherited FGFR3 mutation permanently activates the fibroblast growth factor receptor 3 (FGFR3) and its downstream mitogen-activated protein kinase (MAPK) signalling pathway. This inhibits chondrocyte differentiation and puts a break on growth plate function, in addition to causing serious medical complications such as foramen magnum and spinal stenosis and upper airway narrowing. A great deal has been learned about complications and consequences of FGFR3 activation and management guidance is evolving aimed to reduce the increased mortality and morbidity in this condition, particularly deaths from spinal cord compression and sleep apnoea in infants and small children. To date, no drugs are licensed for treatment of achondroplasia. Here, we report on the various substances in the drug development pipeline which target elements in molecular disease mechanism such as FGF (fibroblast growth factor) ligands, FGFR3, MAPK signalling as well as the C‑type natriuretic peptide receptor NPR‑B (natriuretic peptide receptor B).

Progress in Research on the Role of FGF in the Formation and Treatment of Corneal Neovascularization

Corneal neovascularization (CNV) is a sight-threatening disease usually associated with inflammatory, infectious, degenerative, and traumatic disorders of the ocular surface. Fibroblast growth factor (FGF) family members play an important role in angiogenesis to induce corneal neovascularization, which significantly affects the differentiation, proliferation, metastasis, and chemotaxis of vascular endothelial cells. Both acidic fibroblast growth factor (aFGF) and basic fibroblast growth factor (bFGF) demonstrate positive staining in capillaries and induce corneal stromal cells. The anabolism of endothelial cells is induced by bFGF in corneal neovascularization. FGFs exert their effects via specific binding to cell surface-expressed specific receptors. We believe that both anti-FGF antibodies and anti-FGF receptor antibodies represent new directions for the treatment of CNV. Similar to anti-vascular endothelial growth factor antibodies, subconjunctival injection and eye drops can be considered effective forms of drug delivery.

Aptamers as Versatile Ligands for Biomedical and Pharmaceutical Applications

Aptamers are a class of targeting ligands that bind exclusively to biomarkers of interest. Aptamers have been identified as candidates for the construction of various smart systems for therapy, diagnosis, bioimaging, and drug delivery due to their high target affinity and specificity. Aptamers are accounted as chemical antibodies that can be readily linked to drugs, sensors, signal enhancers, or nanocarriers for functionalization. Use of aptamer-guided medications, especially nanomedicines, has resulted in encouraging outcomes compared to those use of aptamer-free counterparts. This article reviews recent advances in the use of aptamers as targeting ligands for various biomedical and pharmaceutical purposes. Special interests focus on aptamer-based theranostics, biosensing, bioimaging, drug potentiation, and targeted drug delivery.

Anti-Angiogenic and Anti-Scarring Dual Action of an Anti-Fibroblast Growth Factor 2 Aptamer in Animal Models of Retinal Disease

Currently approved therapies for age-related macular degeneration (AMD) are inhibitors against vascular endothelial growth factor (VEGF), which is a major contributor to the pathogenesis of neovascular AMD (nAMD). Intravitreal injections of anti-VEGF drugs have shown dramatic visual benefits for AMD patients. However, a significant portion of AMD patients exhibit an incomplete response to therapy and, over the extended management course, can lose vision, with the formation of submacular fibrosis as one risk factor. We investigated a novel target for AMD treatments, fibroblast growth factor 2 (FGF2), which has been implicated in the pathophysiology of both angiogenesis and fibrosis in a variety of tissue and organ systems. The anti-FGF2 aptamer, RBM-007, was examined for treatment of nAMD in animal models. In in vivo studies conducted in mice and rats, RBM-007 was able to inhibit FGF2-induced angiogenesis, laser-induced choroidal neovascularization (CNV), and CNV with fibrosis. Pharmacokinetic studies of RBM-007 in the rabbit vitreous revealed high and relatively long-lasting profiles that are superior to other approved anti-VEGF drugs. The anti-angiogenic and anti-scarring dual action of RBM-007 holds promise as an additive or alternative therapy to anti-VEGF treatments for nAMD.

Effect of FGF/FGFR pathway blocking on lung adenocarcinoma and its cancer-associated fibroblasts

Cancer-associated fibroblasts (CAFs) are known to promote tumourigenesis through various mechanisms. Fibroblast growth factor (FGF)/FGF receptor (FGFR)-dependent lung cancers have been described. We have developed a mouse model of lung adenocarcinoma that was constructed through the induction of Fgf9 overexpression in type 2 alveolar cells. The expression of Fgf9 in adult lungs resulted in the rapid development of multiple adenocarcinoma-like tumour nodules. Here, we have characterised the contribution of CAFs and the Fgf/Fgfr signalling pathway in maintaining the lung tumours initiated by Fgf9 overexpression. We found that CAF-secreted Fgf2 contributes to tumour cell growth. CAFs overexpressed Tgfb, Mmp7, Fgf9, and Fgf2; synthesised more collagen, and secreted inflammatory cell-recruiting cytokines. CAFs also enhanced the conversion of tumour-associated macrophages (TAMs) to the tumour-supportive M2 phenotype but did not influence angiogenesis. In vivo inhibition of Fgfrs during early lung tumour development resulted in significantly smaller and fewer tumour nodules, whereas inhibition in established lung tumours caused a significant reduction in tumour size and number. Fgfr inhibition also influenced tumour stromal cells, as it significantly abolished TAM recruitment and reduced tumour vascularity. However, the withdrawal of the inhibitor caused a significant recurrence/regrowth of Fgf/Fgfr-independent lung tumours. These recurrent tumours did not possess a higher proliferative or propagative potential. Our results provide evidence that fibroblasts associated with the Fgf9-induced lung adenocarcinoma provide multiple means of support to the tumour. Although the Fgfr blocker significantly suppressed the tumour and its stromal cells, it was not sufficient to completely eliminate the tumour, probably due to the emergence of alternative (resistance/maintenance) mechanism(s). This model represents an excellent tool to further study the complex interactions between CAFs, their related chemokines, and the progression of lung adenocarcinoma; it also provides further evidence to support the need for a combinatorial strategy to treat lung cancer. © 2019 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

The FGF2 aptamer inhibits the growth of FGF2-FGFR pathway driven lung cancer cells

Cancers, including lung cancer, are a leading cause of death worldwide. To overcome this deadly disease, multiple modality inhibitors have been developed. These include cytotoxic agents, molecular targeted small molecules, such as tyrosine kinase inhibitors, and neutralizing antibodies. An aptamer is a short single-stranded nucleic acid molecule that is selected in vitro from a large random sequence library based on its high and specific affinity to a target molecule. Aptamers can be applied to therapeutics of various types of diseases, including cancer, due to their strong and specific neutralizing activities. However, the efficacy of aptamer-based therapy for cancer cells is not well characterized. In this study, we aimed to show that the FGF2 aptamer is effective for the treatment of FGF2 dependent lung cancer cells. We previously developed PC9GR lung cancer cells, whose proliferation is dependent on EGFR and FGF2-FGFR pathways in a cell autonomous manner. Using PC9GR cells, we demonstrate that the addition of the FGF2 aptamer induces more significant inhibition of PC9GR cell proliferation than does the addition of EGFR inhibitor alone. Furthermore, the addition of the FGF2 aptamer more significantly inhibits the downstream signals and induces apoptosis to a higher extent than does the addition of EGFR inhibitor alone. Our results show that the FGF2 aptamer inhibits the growth of FGF2-FGFR pathway-dependent lung cancer cells. The findings provide preclinical evidence that aptamers can be useful for cancer treatment.

Alkaline-tolerant RNA aptamers useful to purify acid-sensitive antibodies in neutral conditions

Recently, several oligonucleotides have been launched for clinical use and a number of therapeutic oligonucleotides are under clinical trials. Aptamer is one of the oligonucleotide therapeutics and has received a lot of attention as a new technology and an efficacious pharmaceutical compound comparable to antibody. Aptamer could be used for various purposes, not only therapeutics but also diagnostics, and applicable to affinity chromatography as a carrier molecule to purify proteins of interest. Here we demonstrate the usage and advantages of RNA aptamer to Fc region of human IgG (i.e., IgG aptamer) for purification of human antibodies. IgG aptamer requires divalent cations for binding to IgG and bound IgG dissociates easily upon treatment with chelating reagent, such as EDTA, under neutral conditions. This elution step is very mild and advantageous for maintaining active conformations of therapeutic antibodies compared to the widely used affinity purification with Protein A/G, which requires acidic elution that often damages the active conformation of antibodies. In fact, of several monoclonal antibodies tested, three antibodies were prone to aggregate on acidic elution from the Protein A/G resin, while remained fully active upon neutral elution from the IgG aptamer resin. The IgG aptamer was fully manipulated to alkaline resistant by ribose 2'-modifications, and thereby reusable numerous times with 1 N NaOH washing. The capacity of the aptamer resin to bind IgG was equivalent to that of the Protein A/G resin. Therefore, the IgG aptamer will provide us with a unique tool to uncover and purify human monoclonal antibodies, which hold therapeutic potential but lose the activity upon acidic elution from Protein A/G-based affinity resin.

Aptamers as therapeutic middle molecules

Therapeutic molecules can be classified as low-, middle- and high-molecular weight drugs depending on their molecular masses. Antibodies represent high-molecular weight drugs and their clinical applications have been developing rapidly. Aptamers, on the other hand, are middle-molecular weight molecules that are short, single-stranded nucleic acid sequences that are selected in vitro from large oligonucleotide libraries based on their high affinity to a target molecule. Hence, aptamers can be thought of as a nucleic acid analog to antibodies. However, several viewpoints hold that the potential of aptamers arises from interesting characteristics that are distinct from, or in some cases, superior to those of antibodies. Recently, therapeutic middle molecules gain considerable attention as protein-protein interaction (PPI) inhibitors. This review summarizes the recent achievements in aptamer development in our laboratory in terms of PPI and non-PPI inhibitors.

Optimization and In Vivo Profiling of a Refined Rat Model of Walker 256 Breast Cancer Cell-Induced Bone Pain Using Behavioral, Radiological, Histological, Immunohistochemical and Pharmacological Methods

In the majority of patients with advanced breast cancer, there is metastatic spread to bones resulting in pain. Clinically available drug treatments for alleviation of breast cancer-induced bone pain (BCIBP) often produce inadequate pain relief due to dose-limiting side-effects. A major impediment to the discovery of novel well-tolerated analgesic agents for the relief of pain due to bony metastases is the fact that most cancer-induced bone pain models in rodents relied on the systemic injection of cancer cells, causing widespread formation of cancer metastases and poor general animal health. Herein, we have established an optimized, clinically relevant Wistar Han female rat model of breast cancer induced bone pain which was characterized using behavioral assessments, radiology, histology, immunohistochemistry and pharmacological methods. In this model that is based on unilateral intra-tibial injection (ITI) of Walker 256 carcinoma cells, animals maintained good health for at least 66 days post-ITI. The temporal development of hindpaw hypersensitivity depended on the initial number of Walker 256 cells inoculated in the tibiae. Hindpaw hypersensitivity resolved after approximately 25 days, in the continued presence of bone tumors as evidenced by ex vivo histology, micro-computed tomography scans and immunohistochemical assessments of tibiae. A possible role for the endogenous opioid system as an internal factor mediating the self-resolving nature of BCIBP was identified based upon the observation that naloxone, a non-selective opioid antagonist, caused the re-emergence of hindpaw hypersensitivity. Bolus dose injections of morphine, gabapentin, amitriptyline and meloxicam all alleviated hindpaw hypersensitivity in a dose-dependent manner. This is a first systematic pharmacological profiling of this model by testing standard analgesic drugs from four important diverse classes, which are used to treat cancer induced bone pain in the clinical setting. Our refined rat model more closely mimics the pathophysiology of this condition in humans and hence is well-suited for probing the mechanisms underpinning breast cancer induced bone pain. In addition, the model may be suitable for efficacy profiling of new molecules from drug discovery programs with potential to be developed as novel agents for alleviation of intractable pain associated with disseminated breast cancer induced bony metastases.

NMR monitoring of the SELEX process to confirm enrichment of structured RNA

RNA aptamers are RNA molecules that bind to a target molecule with high affinity and specificity using uniquely-folded tertiary structures. RNA aptamers are selected from an RNA pool typically comprising up to 1015 different sequences generated by iterative steps of selection and amplification known as Systematic Evolution of Ligands by EXponential enrichment (SELEX). Over several rounds of SELEX, the diversity of the RNA pool decreases and the aptamers are enriched. Hence, monitoring of the enrichment of these RNA pools is critical for the successful selection of aptamers, and several methods for monitoring them have been developed. In this study, we measured one-dimensional imino proton NMR spectra of RNA pools during SELEX. The spectrum of the initial RNA pool indicates that the RNAs adopt tertiary structures. The structural diversity of the RNA pools was shown to depend highly on the design of the primer-binding sequence. Furthermore, we demonstrate that enrichment of RNA aptamers can be monitored using NMR. The RNA pools can be recovered from the NMR tube after measurement of NMR spectra. We also can monitor target binding in the NMR tubes. Thus, we propose using NMR to monitor the enrichment of structured aptamers during the SELEX process.

Selenadiazole derivatives antagonize glucocorticoid-induced osteoblasts cells apoptosis by blocking ROS-mediated signaling, a new anti-osteoporosis strategy

Herein we demonstrate that synthetic selenadiazole derivatives could protect osteoblasts cells against Dex-induced cell apoptosisviaattenuating oxidative stress and downstream signalling pathways.