Development of a novel engineered antibody targeting human CD123

Development of an ostrich-derived single-chain variable fragment (scFv) against PTPRN extracellular domain

In type 1 diabetes, the immune system destroys pancreatic beta cells in an autoimmune condition. To overcome this disease, a specific monoclonal antibody that binds to pancreatic beta cells could be used for targeted immunotherapy. Protein tyrosine phosphatase receptor N (PTPRN) is one of the important surface antigen candidates. Due to its high sequence homology among mammals, so far, no single-chain monoclonal antibody has been produced against this receptor. In this study, we developed a novel single-chain variable fragment (scFv) against the PTPRN extracellular domain. To this aim, ostrich species was used as a host is far phylogenetically birds from mammals to construct a phage display library for the first time. An ostrich-derived scfv phage display library was prepared and biopanning steps were done to enrich and screen for isolating the best anti-PTPRN binders. An scFv with appropriate affinity and specificity to the PTPRN extracellular domain was selected and characterized by ELISA, western blotting, and flow cytometry. The anti-PTPRN scFv developed in this study could be introduced as an effective tool that can pave the way for the creation of antibody-based targeting systems in cooperation with the detection and therapy of type I diabetes.

Single-Chain Fragment Variable: Recent Progress in Cancer Diagnosis and Therapy

Simple Summary

Recombinant antibody fragments have shown remarkable potential as diagnostic and therapeutic tools in the fight against cancer. The single-chain fragment variable (scFv) that contains the complete antigen-binding domains of a whole antibody, has several advantages such as a high specificity and affinity for antigens, a low immunogenicity, and the proven ability to penetrate tumor tissues and diffuse. This review provides an overview of the current studies on the principle, generation, and applications of scFvs, particularly in the diagnosis and therapy of cancer, and underscores their potential use in clinical trials.

Abstract

Cancer remains a public health problem worldwide. Although conventional therapies have led to some excellent outcomes, some patients fail to respond to treatment, they have few therapeutic alternatives and a poor survival prognosis. Several strategies have been proposed to overcome this issue. The most recent approach is immunotherapy, particularly the use of recombinant antibodies and their derivatives, such as the single-chain fragment variable (scFv) containing the complete antigen-binding domains of a whole antibody that successfully targets tumor cells. This review describes the recent progress made with scFvs as a cancer diagnostic and therapeutic tool, with an emphasis on preclinical approaches and their potential use in clinical trials.

Breast cancer immunotherapy: Current and novel approaches

The crucial role of the immune system in the progression/regression of breast cancer (BC) should always be taken into account. Various immunotherapy approaches have been investigated for BC, including tumor-targeting antibodies (bispecific antibodies), adoptive T cell therapy, vaccines, and immune checkpoint blockade such as anti-PD-1. In addition, a combination of conventional chemotherapy and immunotherapy approaches contributes to improving patients' overall survival rates. Although encouraging outcomes have been reported in most clinical trials of immunotherapy, some obstacles should still be resolved in this regard. Recently, personalized immunotherapy has been proposed as a potential complementary medicine with immunotherapy and chemotherapy for overcoming BC. Accordingly, this review discusses the brief association of these methods and future directions in BC immunotherapy.

Anti-CXCR4 Single-Chain Variable Fragment Antibodies Have Anti-Tumor Activity

Monoclonal antibodies (mAbs) are large and have limitations as cancer therapeutics. Human single-chain variable fragment (scFv) is a small antibody as a good alternative. It can easily enter cancer tissues, has no immunogenicity and can be produced in bacteria to decrease the cost. The chemokine receptor CXCR4 is overexpressed in different cancer cells. It plays an important role in tumor growth and metastasis. Its overexpression is associated with poor prognosis in cancer patients and is regarded as an attractive target for cancer treatment. In this study, a peptide on the CXCR4 extracellular loop 2 (ECL2) was used as an antigen for screening a human scFv antibody library by yeast two-hybrid method. Three anti-CXCR4 scFv antibodies were isolated. They could bind to CXCR4 protein and three cancer cell lines (DU145, PC3, and MDA-MB-231) and not to 293T and 3T3 cells as negative controls. These three scFvs could decrease the proliferation, migration, and invasion of these cancer cells and promote their apoptosis. The two scFvs were further examined in a mouse xenograft model, and they inhibited the tumor growth. Tumor immunohistochemistry also demonstrated that the two scFvs decreased cancer cell proliferation and tumor angiogenesis and increased their apoptosis. These results show that these anti-CXCR4 scFvs can decrease cancer cell proliferation and inhibit tumor growth in mice, and may provide therapy for various cancers.

An updated review of pharmacokinetic drug interactions and pharmacogenetics of statins

INTRODUCTION

Hydroxymethylglutaryl-coenzyme A reductase inhibitors (statins) lower cholesterol synthesis in patients with hypercholesterolemia. Increased statin exposure is an important risk factor for skeletal muscle toxicity. Potent inhibitors of cytochrome P450 (CYP) 3A4 significantly increase plasma concentrations of the active forms of simvastatin, lovastatin, and atorvastatin. Fluvastatin is metabolized by CYP2C9, whereas pravastatin, rosuvastatin, and pitavastatin are unaffected by inhibition by either CYP. Statins also have different affinities for membrane transporters involved in processes such as intestinal absorption, hepatic absorption, biliary excretion, and renal excretion.

AREAS COVERED

In this review, the pharmacokinetic aspects of drug-drug interactions with statins and genetic polymorphisms of CYPs and drug transporters involved in the pharmacokinetics of statins are discussed.

EXPERT OPINION

Understanding the mechanisms underlying statin interactions can help minimize drug interactions and reduce the adverse side effects caused by statins. Since recent studies have shown the involvement of drug transporters such as OATP and BCRP as well as CYPs in statin pharmacokinetics, further clinical studies focusing on the drug transporters are necessary. The establishment of biomarkers based on novel mechanisms, such as the leakage of microRNAs into the peripheral blood associated with the muscle toxicity, is important for the early detection of statin side effects.

Impact of CD123 expression, analyzed by immunohistochemistry, on clinical outcomes in patients with acute myeloid leukemia

Aberrant expression of the interleukin-3 receptor alpha chain (IL3RA or CD123) is frequently observed in patients with a subset of leukemic disorders, including acute myeloid leukemia (AML), particularly in leukemia stem cells. We analyzed the relationships between immunohistochemical (IHC) expression, including that of CD123, and clinical outcomes. This study involved a retrospective analysis of 48 patients diagnosed with de novo AML (M0-M5, n = 48) at our hospital between February 2008 and September 2015. Among patients with de novo AML, CD123 expression was associated with a failure to achieve complete response (CR) to initial induction chemotherapy (P = 0.044) and poor overall survival (OS) (P = 0.036). This is the first study using IHC to demonstrate that CD123 expression is associated with a poor CR rate and poor OS in de novo AML patients. These results support previous reports using flow cytometry (FCM). CD123 expression may thus be useful for assessing AML patients' prognoses. At the time of diagnosis, CD123 expression analysis using IHC may represent a clinically useful assessment for de novo AML patients.

New synergistic combinations of differentiation-inducing agents in the treatment of acute promyelocytic leukemia cells

Acute promyelocytic leukemia (APL) was considered to be one of the most lethal forms of leukemia in adults before the introduction of the vitamin A metabolite all-trans retinoic acid (ATRA). Surprisingly, it has been confirmed that FICZ (6-Formylindolo (3, 2-b) carbazole) enhances ATRA-induced differentiation. Moreover, a number of studies have demonstrated that anti CD44 monoclonal antibody (mAb) induces to bring back differentiation blockage the leukemic stem cells. The level of differentiation markers including CD11b and CD11c in NB4 cells was assessed by flow cytometry. The induction of apoptosis was also evaluated. We estimated the induction potential of a triple compound of ATRA-FICZ, anti-CD44 maps. The cells showed the gradually increased expression levels of CD11b and CD11c. A mixture of a "CD44 mAb, ATRA and FICZ effectively promoted granulocytic maturation resulting in increased rates of apoptosis. The differences in expression of CD11b and CD11c at 5 μg/ml and 10 μg/ml were significant. These phenomena were highest at 10 μg/ml CD44 mAb concentrations. Synergistic induction differentiation and apoptosis of APL cells by using a co-treatment with novel triple compound are more effective for eradicating blasts and controlling the metastasis. Our results show that the addition of anti-CD44 mAb improves "ATRA-FICZ"-induced differentiation and has potential to reduce usual chemotherapy based treatments. Taken together, this compound may lead to novel clinical applications of differentiation-based approaches for APL and other types of leukemia. Further clinical studies would be recommended to clarify the clinical efficacy.

Novel CD123-aptamer-originated targeted drug trains for selectively delivering cytotoxic agent to tumor cells in acute myeloid leukemia theranostics

Since conventional chemotherapy for acute myeloid leukemia (AML) has its limitations, a theranostic platform with targeted and efficient drug transport is in demand. In this study, we developed the first CD123 (AML tumor marker) aptamers and designed a novel CD123-aptamer-mediated targeted drug train (TDT) with effective, economical, biocompatible and high drug-loading capacity. These two CD123 aptamers (termed as ZW25 and CY30, respectively) can bind to a CD123 peptide epitope and CD123 + AML cells with high specificities and KD of 29.41 nM and 15.38 nM, respectively, while has minimal cross reactivities to albumin, IgG and trypsin. Further, TDT is self-assembled from two short primers by ligand-modified ZW25 that acted as initiation position for elongation, while intercalated by doxorubicin (Dox). TDT is capable of transporting high capacity of Dox to CD123 + cells and retains the efficacy of Dox, while significantly reducing drug uptake and eased toxicity to CD123- cells in vitro (p < .01). Moreover, TDT can ease Dox cytoxicity to normal tissues, prolong survivals and inhibit tumor growth of mouse xenograft tumor model in vivo. These suggest that CD123 aptamer and CD123 aptamer-mediated targeted drug delivery system may have potential applications for selective delivery cytotoxic agents to CD123-expressing tumors in AML theranostics.

Datasets of a novel bivalent single chain antibody constructed by overlapping oligonucleotide annealing method targeting human CD123

Current therapies for acute myeloid leukemia (AML), are associated with high relapse rates. Hence, development of new therapeutic strategies is crucial to circumvent this problem. Bivalent antibody technology has been used to engineer novel antibody fragments with increased avidity, by assembling two scFv in a single molecule. Here, we present accompanying data from construction and characterization experiments of a biscFv antibody targeting CD123, the most important biomarker of leukemic cancer stem cells which play a key role in relapsed AML after chemotherapy. Data in this article are related to the research paper “Development of a novel engineered antibody targeting human CD123” Moradi-Kalbolandi S. et al. (2016) [1].