Potential drugs used in the antibody–drug conjugate (ADC) architecture for cancer therapy

Cytotoxic small-molecule drugs have a major influence on the fate of antibody–drug conjugates (ADCs). An ideal cytotoxic agent should be highly potent, remain stable while linked to ADCs, kill the targeted tumor cell upon internalization and release from the ADCs, and maintain its activity in multidrug-resistant tumor cells. Lessons learned from successful and failed experiences in ADC development resulted in remarkable progress in the discovery and development of novel highly potent small molecules. A better understanding of such small-molecule drugs is important for development of effective ADCs. The present review discusses requirements making a payload appropriate for antitumor ADCs and focuses on the main characteristics of commonly-used cytotoxic payloads that showed acceptable results in clinical trials. In addition, the present study represents emerging trends and recent advances of payloads used in ADCs currently under clinical trials. © 2019 Wiley Periodicals, Inc

Development of a novel explant culture method for the isolation of mesenchymal stem cells from human breast tumor

Background: Mesenchymal stem cells (MSCs) were isolated from various sources, including various types of tumors. However choosing an appropriate isolation method is an important step in obtaining cells with optimal quality and yield in companion with economical considerations. The purpose of this study was to isolate more pure MSCs from human breast tumor tissue by a modified explant culture method. Methods and Materials: The tumor tissues (n = 8) were cut into 1 to 3-mm cube-like pieces (explant). Each explant was placed in a well of 24-well format plates, cultured in Dulbecco’s Modified Eagle’s medium (DMEM), and maintained at 37°C with 5 humidified incubator. Morphological phenotypes of the cells were surveyed by an inverted microscope and wells with rather homogenous fibroblast-like morphology cell were considered as positive and selected for more expansion and characterization. Results: A total of 185 wells, 63.7 of wells were positive that were chosen for expansion. Flowcytometry analysis demonstrated that isolated cells were positive for CD73, CD44, CD29, CD105, and CD90 but negative for CD11b, CD45, CD34, and HLA‑DR. In addition, cells possessed the capability of multipotential differentiation into osteoblasts and adipocytes. © 2018 Taylor & Franci

The effect of CRISPR constructs microinjection on the expression of developmental genes in Rag1 knocked-out mice embryo

Despite all the advances in the production of transgenic mice, the production efficiency of these animal models is still low. Given that the expression of developmental genes has a critical role in growth and development of embryo, we determined the expression pattern of pluripotency, trophectoderm and imprinting genes in the Rag1 (recombination-activating gene 1) knocked-out blastocysts resulting from microinjection of CRISPR/Cas9 (clustered regularly interspaced short palindromic repeats/CRISPR-associated protein 9) constructs into the zygote cytoplasm of C57bl6 mice. Following microinjection, the embryos were cultured and the gene expression of developed blastocysts and natural blastocysts (Sham and control groups) were evaluated using real-time PCR. The agarose gel to confirm the deletion in the Rag1 gene in Rag1 knocked-out blastocyst. Our results showed that the expression of trophectoderm genes (-TEAD-4 and Cdx2), pluripotency genes (Nanog and Oct-4) and imprinting gene (H19) in the Rag1 knocked-out group was significantly lower compared with the embryos obtained from Natural fertilization. According to these findings, manipulation, embryo culture and microinjection of CRISPR constructs into the zygote cytoplasm of mice led to reduced expression of imprinting, pluripotency and trophectoderm genes. Therefore, the Rag1 knocked-out embryos produced by the CRISPR/Cas9 system are of low quality, which reduces the chances of live birth in these animals and may cause various abnormalities in fetuses. © 2021 The Authors Veterinary Medicine and Science Published by John Wiley & Sons Lt

Comparative immunomodulatory properties of mesenchymal stem cells derived from human breast tumor and normal breast adipose tissue

Objective: Mesenchymal stem cells (MSCs), one of the most important stromal cells in the tumor microenvironment, play a major role in the immunomodulation and development of tumors. In contrast to immunomodulatory effects of bone marrow-derived MSCs, resident MSCs were not well studied in tumor. The aim of this study was to compare the immunomodulatory properties and protein secretion profiles of MSCs isolated from breast tumor (T-MSC) and normal breast adipose tissue (N-MSC). Materials and methods: T-MSCs and N-MSCs were isolated by the explant culture method and characterized, and their immunomodulatory function was assessed on peripheral blood lymphocytes (PBLs) by evaluating the effects of MSC conditioned media on the proliferation and induction of some cytokines and regulatory T cells (Tregs) by BrdU assay, ELISA, and flow cytometry. In addition, we compared the secretion of indoleamine 2,3-dioxygenase (IDO), vascular endothelial growth factor (VEGF), matrix metallopeptidase (MMP)-2, MMP-9, and Galectin-1. Results: T-MSCs showed a higher secretion of transforming growth factor beta (TGF-β), prostaglandin E2 (PGE2), IDO, and VEGF and lower secretion of MMP-2 and MMP-9 compared with N-MSCs. However, no significant difference was found in the secretion of interferon gamma (IFN-γ), interleukin 10 (IL10), IL4, IL17, and Galectin-1 in T-MSCs and N-MSCs. The immunomodulatory effect of soluble factors on PBLs showed that T-MSCs, in contrast to N-MSCs, stimulate PBL proliferation. Importantly, the ability of T-MSCs to induce IL10, TGF-β, IFN-γ, and PGE2 was higher than that of N-MSCs. In addition, T-MSCs and N-MSCs exhibited no significant difference in Treg induction. Conclusion: MSCs educated in stage II breast cancer and normal breast adipose tissue, although sharing a similar morphology and immunophenotype, exhibited a clearly different profile in some immunomodulatory functions and protein secretions. © 2020, Springer-Verlag GmbH Germany, part of Springer Nature

Protective effects of pharmacological agents against aminoglycoside-induced nephrotoxicity: A systematic review

Introduction: Aminoglycosides have been long used for antibacterial treatment and are still commonly used in clinical practice. Despite their extensive application and positive effects, drug-related toxicity is considered as the main obstacle for aminoglycosides. Aminoglycosides induce nephrotoxicity through the endocytosis and accumulation of the antibiotics in the epithelial cells of proximal tubule. Most importantly, however, a number of pharmacological agents were demonstrated to have protective activities against nephrotoxicity in experimental animals. Areas covered: In the present systematic review, the authors provide and discuss the mechanisms and epidemiological features of aminoglycoside-induced nephrotoxicity, and focus mainly on recent discoveries and key features of pharmacological interventions. In total, 39 articles were included in this review. Expert opinion: The majority of studies investigated gentamicin-induced nephrotoxicity in animal models. Antioxidants, chemicals, synthetic drugs, hormones, vitamins, and minerals showed potential values to prevent gentamicin-induced nephrotoxicity. Indicators used to evaluate the effectiveness of nephroprotection included antioxidative indexes, inflammatory responses, and apoptotic markers. Among the nephroprotective agents studied, herbs and natural antioxidant agents showed excellent potential to provide a protective strategy against gentamicin-induced nephrotoxicity. © 2020, © 2020 Informa UK Limited, trading as Taylor & Francis Group

Potential drugs used in the antibody-drug conjugate (ADC) architecture for cancer therapy

Cytotoxic small-molecule drugs have a major influence on the fate of antibody-drug conjugates (ADCs). An ideal cytotoxic agent should be highly potent, remain stable while linked to ADCs, kill the targeted tumor cell upon internalization and release from the ADCs, and maintain its activity in multidrug-resistant tumor cells. Lessons learned from successful and failed experiences in ADC development resulted in remarkable progress in the discovery and development of novel highly potent small molecules. A better understanding of such small-molecule drugs is important for development of effective ADCs. The present review discusses requirements making a payload appropriate for antitumor ADCs and focuses on the main characteristics of commonly-used cytotoxic payloads that showed acceptable results in clinical trials. In addition, the present study represents emerging trends and recent advances of payloads used in ADCs currently under clinical trials

Trastuzumab-monomethyl auristatin E conjugate exhibits potent cytotoxic activity in vitro against HER2-positive human breast cancer

Targeted therapy using specific monoclonal antibodies (mAbs) conjugated to chemotherapeutic agents or toxins has become one of the top priorities in cancer therapy. Antibody�drug conjugates (ADCs) are emerging as a promising strategy for cancer-targeted therapy. In this study, trastuzumab, a humanized monoclonal anti-HER2 antibody, was reduced by dithiothreitol and conjugated to the microtubule-disrupting agent monomethyl auristatin E (MMAE) through a valine-citrulline peptide linker (trastuzumab-MC-Val-Cit-PABC-MMAE trastuzumab-vcMMAE). After conjugation, ADCs were characterized by using UV�vis, sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), and flow cytometry. The antitumor activity of the ADC was evaluated in breast cancer cells in vitro. In addition, ADCs were further characterized using purification by the protein A chromatography, followed by assessment using apoptosis and MTT (3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide) assays. Hydrophobic interaction chromatography was used to determine drug-to-antibody ratio species of ADCs produced. Our finding showed that approximately 5.12 drug molecules were conjugated to each mAb. H2L2, H2L, HL, H2, H, and L forms of ADCs were detected in nonreducing SDS-PAGE. The binding of trastuzumab-vcMMAE to HER2-positive cells was comparable with that of the parental mAb. The MTT assay showed that our ADCs induced significant cell death in HER2-positive cells, but not in HER2-negative cells. The ADCs produced was a mixture of species, unconjugated trastuzumab (14.147%), as well as trastuzumab conjugated with two (44.868%), four (16.886%), six (13.238%), and eight (10.861%) molecules of MMAE. These results indicated that MMAE-conjugated trastuzumab significantly increases the cytotoxic activity of trastuzumab, demonstrating high affinity, specificity, and antitumor activity in vitro. Trastuzumab-vcMMAE is an effective and selective agent for the treatment of HER2-positive breast tumors. © 2018 Wiley Periodicals, Inc