Characterization of A Bifunctional Synthetic RNA Aptamer and A Truncated Form for Ability to Inhibit Growth of Non-Small Cell Lung Cancer

Targeted therapy for cisplatin-resistant lung cancer via aptamer-guided nano-zinc carriers containing USP14 siRNA

Cisplatin (DDP) is a common therapeutic option for non-small cell lung carcinoma (NSCLC). However, some patients fail to respond to the DDP chemotherapy. Therefore, identifying novel biomarkers to improve the diagnosis and treatment of NSCLC is important. Ubiquitin-specific protease (USP14) is involved in various pathological conditions including cancer; however, the role of USP14 in NSCLC remains elusive. The SELEX technology was used to identify aptamers that specifically recognize DDP-resistant lung cancer cells and couple them with nano-zinc (zinc hydroxide, Zn(OH)2) carriers. USP14 levels were higher in DDP-resistant lung cancer compared to DDP-sensitive lung cancer. The survival rate of lung cancer patients with increased USP14 expression was significantly lower than the survival rate of patients with low USP14 expression. Silencing USP14 increased the tumor antagonistic action of DDP in A549 cisplatin-resistant (A549/DDP) cells, while USP14 overexpression decreased the antagonist effects. Aptamer-targeted nano-zinc carriers were loaded with USP14 siRNA to target DDP-resistant lung cancer cells. Aptamer-targeted nano-zinc carriers containing USP14 siRNA increased the antitumor effects of DDP in A549/DDP cells and mice bearing A549/DDP cells. These results indicate that aptamer-guided nano-zinc carriers may be a potent carrier for the precise treatment of drug-resistant tumors.

Identification and characterization of a novel cell binding and cross-reactive region on spike protein of SARS-CoV-2

Given that COVID-19 continues to wreak havoc around the world, it is imperative to search for a conserved region involved in viral infection so that effective vaccines can be developed to prevent the virus from rapid mutations. We have established a twelve-fragment library of recombinant proteins covering the entire region of spike protein of both SARS-CoV-2 and SARS-CoV from Escherichia coli. IgGs from murine antisera specifically against 6 spike protein fragments of SARS-CoV-2 were produced, purified, and characterized. We found that one specific IgG against the fusion process region, named COVID19-SF5, serologically cross-reacted with all twelve S-protein fragments. COVID19-SF5, with amino acid sequences from 880 to 1084, specifically bound to VERO-E6 and BEAS-2B cells, with K_d values of 449.1 ± 21.41 and 381.9 ± 31.53 nM, and IC₅₀ values of 761.2 ± 28.2 nM and 862.4 ± 32.1 nM, respectively. In addition, COVID19-SF5 greatly enhanced binding of the full-length CHO cell-derived spike protein to the host cells in a concentration-dependent manner. Furthermore, COVID19-SF5 and its IgGs inhibited the infection of the host cells by pseudovirus. The combined data from our studies reveal that COVID19-SF5, a novel cell-binding fragment, may contain a common region(s) for mediating viral binding during infection. Our studies also provide valuable insights into how virus variants may evade host immune recognition. Significantly, the observation that the IgGs against COVID19-SF5 possesses cross reactivity to all other fragments of S protein, suggesting that it is possible to develop universal neutralizing monoclonal antibodies to curb rapid mutations of COVID-19.

Cell-specific aptamers as potential drugs in therapeutic applications: A review of current progress

Cell-specific aptamers are a promising emerging player in the field of disease therapy. This paper reviews the multidimensional research progress made in terms of their classification, modification, and application. Based on the target location of cell-specific aptamers, it is defined and classified cell-specific aptamers into three groups including aptamers for cell surface markers, aptamers for intracellular components, and aptamers for extracellular components. Moreover, the modification methods of aptamers to achieve improved stability and affinity are concluded. In addition, recent advances in the application of cell-specific aptamers are discussed, mainly focusing on the increasing research attraction of cell state improving helpers and cell recruitment mediators in the improvement of cellular microenvironments to achieve successful disease therapy. This review also highlights 11 types of clinical aptamer drugs. Finally, the challenges and future directions of potential clinical applications are presented. In summary, we believe that cell-specific aptamers are promising drugs in disease therapy.

Engineering synthetic RNA devices for cell control

The versatility of RNA in sensing and interacting with small molecules, proteins and other nucleic acids while encoding genetic instructions for protein translation makes it a powerful substrate for engineering biological systems. RNA devices integrate cellular information sensing, processing and actuation of specific signals into defined functions and have yielded programmable biological systems and novel therapeutics of increasing sophistication. However, challenges centred on expanding the range of analytes that can be sensed and adding new mechanisms of action have hindered the full realization of the field's promise. Here, we describe recent advances that address these limitations and point to a significant maturation of synthetic RNA-based devices.

Selection of aptamers against triple negative breast cancer cells using high throughput sequencing

Triple-negative breast cancer is the most aggressive subtype of invasive breast cancer with a poor prognosis and no approved targeted therapy. Hence, the identification of new and specific ligands is essential to develop novel targeted therapies. In this study, we aimed to identify new aptamers that bind to highly metastatic breast cancer MDA-MB-231 cells using the cell-SELEX technology aided by high throughput sequencing. After 8 cycles of selection, the aptamer pool was sequenced and the 25 most frequent sequences were aligned for homology within their variable core region, plotted according to their free energy and the key nucleotides possibly involved in the target binding site were analyzed. Two aptamer candidates, Apt1 and Apt2, binding specifically to the target cells with \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$K_{d}$$\end{document}Kd values of 44.3 ± 13.3 nM and 17.7 ± 2.7 nM, respectively, were further validated. The binding analysis clearly showed their specificity to MDA-MB-231 cells and suggested the targeting of cell surface receptors. Additionally, Apt2 revealed no toxicity in vitro and showed potential translational application due to its affinity to breast cancer tissue sections. Overall, the results suggest that Apt2 is a promising candidate to be used in triple-negative breast cancer treatment and/or diagnosis.

Advances in Oligonucleotide Aptamers for NSCLC Targeting

Non-small-cell lung cancer (NSCLC) is the most common type of lung cancer worldwide, with the highest incidence in developed countries. NSCLC patients often face resistance to currently available therapies, accounting for frequent relapses and poor prognosis. Indeed, despite great recent advancements in the field of NSCLC diagnosis and multimodal therapy, most patients are diagnosed at advanced metastatic stage, with a very low overall survival. Thus, the identification of new effective diagnostic and therapeutic options for NSCLC patients is a crucial challenge in oncology. A promising class of targeting molecules is represented by nucleic-acid aptamers, short single-stranded oligonucleotides that upon folding in particular three dimensional (3D) structures, serve as high affinity ligands towards disease-associated proteins. They are produced in vitro by SELEX (systematic evolution of ligands by exponential enrichment), a combinatorial chemistry procedure, representing an important tool for novel targetable biomarker discovery of both diagnostic and therapeutic interest. Aptamer-based approaches are promising options for NSCLC early diagnosis and targeted therapy and may overcome the key obstacles of currently used therapeutic modalities, such as the high toxicity and patients’ resistance. In this review, we highlight the most important applications of SELEX technology and aptamers for NSCLC handling.

Aptamers in Non-Small Cell Lung Cancer Treatment

Aptamers are short, single-stranded oligonucleotides which are capable of specifically binding to single molecules and cellular structures. Aptamers are also known as “chemical antibodies”. Compared to monoclonal antibodies, they are characterized by higher reaction specificity, lower molecular weight, lower production costs, and lower variability in the production stage. Aptamer research has been extended during the past twenty years, but only Macugen^® has been accepted by the Food and Drug Administration (FDA) to date, and few aptamers have been examined in clinical trials. In vitro studies with aptamers have shown that they may take part in the regulation of cancer progression, angiogenesis, and metastasis processes. In this article, we focus on the potential use of aptamers in non-small cell lung cancer treatment.