Interactions of heparin derivatives with recombinant human keratinocyte growth factor: Structural stability and bioactivity effect study

Heparin and heparan sulfate are important glycosaminoglycans that can regulate the activities of many vital proteins, especially the fibroblast growth factor (FGF) family. Because FGF7 (KGF) has an important role in tissue repair and maintaining the integrity of the mucosal barrier, recombinant human keratinocyte growth factor (rhKGF, palifermin) has been approved for the treatment of wound healing and oral cavity. Due to heparin plays an important role in the KGF signaling pathway, a more detailed study of the drug-drug interactions (DDIs) between rhKGF and heparin at the atomic level and investigating their synergistic effect on each other in terms of biology, especially in silico, is necessary for a better understanding of DDIs. In this study, DDIs between rhKGF and low-molecular weight heparin types (LMWH) were investigated. In this regard, scrutiny of the influence of the synergistic heparin types on the structure and biostability of rhKGF is accomplished using computational methods such as molecular docking and molecular dynamic simulations (MDs). Subsequently, the motion behavior of rhKGF in interaction with LMWHs was evaluated based on eigenvectors by using principal component analysis (PCA). Also, the binding free energies of rhKGF-LMWH complexes were calculated by the molecular mechanics/Poisson-Boltzmann surface area (MM-BPSA) method. The result showed that rhKGF-idraparinux (-6.9 kcal/mol) and rhKGF-heparin (-6.0 kcal/mol) complexes had significant binding affinity as well as they had a more stable binding to rhKGF than to other LMWH during 100 ns simulation. However, in order to confirm the curative effect of these drugs, clinical trials must be done.

Roles of the fibroblast growth factor signal transduction system in tissue injury repair

Following injury, tissue autonomously initiates a complex repair process, resulting in either partial recovery or regeneration of tissue architecture and function in most organisms. Both the repair and regeneration processes are highly coordinated by a hierarchy of interplay among signal transduction pathways initiated by different growth factors, cytokines and other signaling molecules under normal conditions. However, under chronic traumatic or pathological conditions, the reparative or regenerative process of most tissues in different organs can lose control to different extents, leading to random, incomplete or even flawed cell and tissue reconstitution and thus often partial restoration of the original structure and function, accompanied by the development of fibrosis, scarring or even pathogenesis that could cause organ failure and death of the organism. Ample evidence suggests that the various combinatorial fibroblast growth factor (FGF) and receptor signal transduction systems play prominent roles in injury repair and the remodeling of adult tissues in addition to embryonic development and regulation of metabolic homeostasis. In this review, we attempt to provide a brief update on our current understanding of the roles, the underlying mechanisms and clinical application of FGFs in tissue injury repair.

Topical heparin as an effective and safe treatment for patients with capecitabine-induced hand-foot syndrome: results of a phase IIA trial supported by proteomic profiling of skin biopsies

Background:

Hand-foot syndrome (HFS) is a common adverse reaction associated with capecitabine chemotherapy that significantly affects the quality of life of patients. This study evaluates the safety and effectiveness of a topical heparin (TH) treatment on the clinical manifestations and anatomopathological alterations of capecitabine-induced HFS. In addition, we performed proteome profiling of skin biopsies obtained from patients with HFS at baseline and after heparin treatment.

Methods:

Patients with grade ⩽ 2 HFS associated with capecitabine were included in this study. The primary end point was the effectiveness of TH in reducing HFS of any grade. Clinical improvement was evaluated by clinicians, and an improvement was perceived by patients who performed a weekly visual analog scale questionnaire. Secondary end points included a comparative histological analysis and protein expression in skin biopsies at baseline and after 3 weeks of HT treatment. Proteomic profiling was carried out using quantitative isobaric labelling and subsequently validated by a T-array.

Results:

Twenty-one patients were included in the study. The median TH treatment time was 7.6 weeks (range = 3.6–41.6 weeks), and the median response time was 3.01 weeks (95% CI = 2.15–3.97). At the end of treatment, 19 of 21 patients (90.48%) responded to treatment with a decrease in one or more grades of HFS. None of the patients experienced adverse effects related to TH usage, nor did they suspend chemotherapy treatment. The main findings observed in skin biopsies after treatment were a decrease in hyperkeratosis and lymphocytic infiltrates. The proteomic analysis showed altered expression of 34 proteins that were mainly related to wound healing, cell growth, and the immune response.

Conclusion:

Based on our results, topical heparin is an effective and safe treatment for clinical manifestations of HFS, probably due to the restauration of skin homeostasis after heparin treatment, as supported by our proteomics-derived data.

Trial registration:

EudraCT 2009-018171-13

Keratinocyte growth factor in focus: A comprehensive review from structural and functional aspects to therapeutic applications of palifermin

Palifermin (Kepivance™) is the first therapeutic approved by the Food and Drug Administration for preventing and managing the oral mucositis provoked by myelotoxic and mucotoxic therapies. Palifermin is a recombinant protein generated from human keratinocyte growth factor (KGF) and imitates the function of endogenous KGF. KGF is an epithelial mitogen involved in various biological processes which belongs to the FGF family. KGF possesses a high level of receptor specificity and plays an important role in tissue repair and maintaining of the mucosal barrier integrity. Based on these unique features, palifermin was developed to enhance the growth of damaged epithelial tissues. Administration of palifermin has shown success in the reduction of toxicities of chemotherapy and radiotherapy, and improvement of the patient's quality of life. Notwithstanding all merits, the clinical application of palifermin is limited owing to its instability and production challenges. Hence, a growing number of ongoing researches are designed to deal with these problems and enhance the physicochemical and pharmaceutical properties of palifermin. In the current review, we discuss KGF structure and function, potential therapeutic applications of palifermin, as well as the latest progress in the production of recombinant human KGF and its challenges ahead.

Targeting Drugs Against Fibroblast Growth Factor(s)-Induced Cell Signaling

BACKGROUND

The fibroblast growth factor (FGF) family is comprised of 23 highly regulated monomeric proteins that regulate a plethora of developmental and pathophysiological processes, including tissue repair, wound healing, angiogenesis, and embryonic development. Binding of FGF to fibroblast growth factor receptor (FGFR), a tyrosine kinase receptor, is facilitated by a glycosaminoglycan, heparin. Activated FGFRs phosphorylate the tyrosine kinase residues that mediate induction of downstream signaling pathways, such as RAS-MAPK, PI3K-AKT, PLCγ, and STAT. Dysregulation of the FGF/FGFR signaling occurs frequently in cancer due to gene amplification, FGF activating mutations, chromosomal rearrangements, integration, and oncogenic fusions. Aberrant FGFR signaling also affects organogenesis, embryonic development, tissue homeostasis, and has been associated with cell proliferation, angiogenesis, cancer, and other pathophysiological changes.

OBJECTIVE

This comprehensive review will discuss the biology, chemistry, and functions of FGFs, and its current applications toward wound healing, diabetes, repair and regeneration of tissues, and fatty liver diseases. In addition, specific aberrations in FGFR signaling and drugs that target FGFR and aid in mitigating various disorders, such as cancer, are also discussed in detail.

CONCLUSION

Inhibitors of FGFR signaling are promising drugs in the treatment of several types of cancers. The clinical benefits of FGF/FGFR targeting therapies are impeded due to the activation of other RTK signaling mechanisms or due to the mutations that abolish the drug inhibitory activity on FGFR. Thus, the development of drugs with a different mechanism of action for FGF/FGFR targeting therapies is the recent focus of several preclinical and clinical studies.

Current trends in drug metabolism and pharmacokinetics

Pharmacokinetics (PK) is the study of the absorption, distribution, metabolism, and excretion (ADME) processes of a drug. Understanding PK properties is essential for drug development and precision medication. In this review we provided an overview of recent research on PK with focus on the following aspects: (1) an update on drug-metabolizing enzymes and transporters in the determination of PK, as well as advances in xenobiotic receptors and noncoding RNAs (ncRNAs) in the modulation of PK, providing new understanding of the transcriptional and posttranscriptional regulatory mechanisms that result in inter-individual variations in pharmacotherapy; (2) current status and trends in assessing drug-drug interactions, especially interactions between drugs and herbs, between drugs and therapeutic biologics, and microbiota-mediated interactions; (3) advances in understanding the effects of diseases on PK, particularly changes in metabolizing enzymes and transporters with disease progression; (4) trends in mathematical modeling including physiologically-based PK modeling and novel animal models such as CRISPR/Cas9-based animal models for DMPK studies; (5) emerging non-classical xenobiotic metabolic pathways and the involvement of novel metabolic enzymes, especially non-P450s. Existing challenges and perspectives on future directions are discussed, and may stimulate the development of new research models, technologies, and strategies towards the development of better drugs and improved clinical practice.

FGF Family: From Drug Development to Clinical Application

Fibroblast growth factor (FGF) belongs to a large family of growth factors. FGFs use paracrine or endocrine signaling to mediate a myriad of biological and pathophysiological process, including angiogenesis, wound healing, embryonic development, and metabolism regulation. FGF drugs for the treatment of burn and ulcer wounds are now available. The recent discovery of the crucial roles of the endocrine-acting FGF19 subfamily in maintaining homeostasis of bile acid, glucose, and phosphate further extended the activity profile of this family. Here, the applications of recombinant FGFs for the treatment of wounds, diabetes, hypophosphatemia, the development of FGF receptor inhibitors as anti-neoplastic drugs, and the achievements of basic research and applications of FGFs in China are reviewed.

Regulation of drug-metabolizing enzymes in infectious and inflammatory disease: implications for biologics-small molecule drug interactions

INTRODUCTION

Drug-metabolizing enzymes (DMEs) are primarily down-regulated during infectious and inflammatory diseases, leading to disruption in the metabolism of small molecule drugs (smds), which are increasingly being prescribed therapeutically in combination with biologics for a number of chronic diseases. The biologics may exert pro- or anti-inflammatory effect, which may in turn affect the expression/activity of DMEs. Thus, patients with infectious/inflammatory diseases undergoing biologic/smd treatment can have complex changes in DMEs due to combined effects of the disease and treatment. Areas covered: We will discuss clinical biologics-SMD interaction and regulation of DMEs during infection and inflammatory diseases. Mechanistic studies will be discussed and consequences on biologic-small molecule combination therapy on disease outcome due to changes in drug metabolism will be highlighted. Expert opinion: The involvement of immunomodulatory mediators in biologic-SMDs is well known. Regulatory guidelines recommend appropriate in vitro or in vivo assessments for possible interactions. The role of cytokines in biologic-SMDs has been documented. However, the mechanisms of drug-drug interactions is much more complex, and is probably multi-factorial. Studies aimed at understanding the mechanism by which biologics effect the DMEs during inflammation/infection are clinically important.

Drug Development of Therapeutic Monoclonal Antibodies

Monoclonal antibodies (MAbs) have become a substantial part of many pharmaceutical company portfolios. However, the development process of MAbs for clinical use is quite different than for small-molecule drugs. MAb development programs require careful interdisciplinary evaluations to ensure the pharmacology of both the MAb and the target antigen are well-understood. Selection of appropriate preclinical species must be carefully considered and the potential development of anti-drug antibodies (ADA) during these early studies can limit the value and complicate the performance and possible duration of preclinical studies. In human studies, many of the typical pharmacology studies such as renal or hepatic impairment evaluations may not be needed but the pharmacokinetics and pharmacodynamics of these agents is complex, often necessitating more comprehensive evaluation of clinical data and more complex bioanalytical assays than might be used for small molecules. This paper outlines concerns and strategies for development of MAbs from the early in vitro assessments needed through preclinical and clinical development. This review focuses on how to develop, submit, and comply with regulatory requirements for MAb therapeutics.

Therapeutic protein-drug interactions: plausible mechanisms and assessment strategies

INTRODUCTION

Over the last three decades, therapeutic proteins have played an increasingly important role in pharmacotherapy. Owing to an expected significant increase in the coadministration of biotherapeutics with established pharmacotherapy regimens or even with other biotherapeutic agents, there is an increasing likelihood for the occurrence of clinically relevant drug interactions, so called therapeutic protein-drug interactions (TP-DIs). Areas covered: Our current understanding of TP-DIs and recent collaborations among industry, academia and regulatory agencies are reviewed in this article. Although most of the observed TP-DIs are mediated by disease states, immune status, and/or target physiology, TP-DI assessments are still done empirically. Plausible mechanisms of major TP-DIs involving therapeutic proteins (primarily monoclonal antibodies), either as victims or as perpetrators, are proposed, with mechanism-based strategies and assessment approaches to better evaluate their propensity are recommended. Expert opinion: Our current understanding of the mechanisms of TP-DIs is in its infancy. Much of the basic research needs to be conducted to verify existing TP-DI hypotheses or help predict and manage potential ones, whose efforts are not considered trivial and may be better achieved through close collaborations among scientists from academia, industry, and regulatory agencies.