Conjugate Potency Assay Service
Overview
The development of ligand-conjugated oligonucleotides has revolutionized the targeting of "undruggable" transcripts. However, the complexity of these multi-component systems, comprising a targeting ligand, a chemical linker, and an oligonucleotide payload, demands rigorous bioactivity validation. CD BioGlyco offers a specialized conjugate potency assay service designed to quantify the functional efficacy of your therapeutic candidates. Our platform evaluates the entire "potency chain," from receptor-mediated internalization to final target mRNA degradation or splicing modulation. By providing high-precision IC50 and EC50 data, we help researchers determine the precise relationship between conjugate structure and biological output, ensuring only the most potent leads progress toward clinical evaluation.
Core Technologies
Our potency assessment platform integrates cutting-edge molecular biology and biophysical tools to provide a holistic view of conjugate performance:
- Quantitative Real-Time PCR (RT-qPCR) & ddPCR
We utilize ultra-sensitive mRNA quantification to measure target knockdown. Our droplet digital PCR (ddPCR) capabilities allow for the absolute quantification of transcripts, providing high-fidelity data even for low-abundance targets.
- Reporter Systems
To assess the direct silencing activity of siRNAs or ASOs, we develop custom reporter constructs. These assays provide a rapid and highly reproducible readout of the conjugate's ability to engage the RNA-induced silencing complex (RISC) or recruit RNase H.
- High-Content Imaging (HCI)
Our automated microscopy platform tracks the spatial distribution of fluorescently labeled conjugates within cells. We quantify endosomal escape efficiency and nuclear localization, which are critical determinants of ASO and siRNA potency.
- Surface Plasmon Resonance (SPR)
We measure the binding kinetics between the conjugate's targeting moiety (e.g., GalNAc or mAb) and its cognate receptor (e.g., ASGPR or Transferrin Receptor). This ensures that the conjugation process has not compromised the ligand's binding affinity.
Validating the Bioactivity of Next-Generation RNA Therapeutics
Our assay service is engineered to support a wide range of therapeutic platforms and research stages. We provide comprehensive bioactivity profiling for GalNAc-siRNA, GalNAc-ASO, peptide-oligonucleotide conjugates, and AOCs. Our scope includes both in vitro and ex vivo assays, utilizing a library of over 200 validated cell lines and access to primary tissues for high-translation studies.
We offer specialized assays for different molecular mechanisms, including RNase-mediated cleavage, RNAi-mediated degradation, steric blocking for exon skipping, and microRNA inhibition. Furthermore, we provide "structure-activity relationship" (SAR) support, where we test the potency of various linker lengths and attachment sites to help you optimize the conjugate's architecture. Whether you are conducting initial lead screening or preparing data for an IND submission, our service provides the quantitative evidence required to validate your therapeutic hypothesis.
Workflow
Assay Design & Customization
Our process begins with the careful selection or genetic engineering of biologically relevant cell models. We prioritize cell lines that reliably express both the target receptor (e.g., ASGPR for GalNAc conjugates) and the endogenous transcript of interest. For liver-targeted therapies, we utilize primary human hepatocytes or advanced co-culture systems to ensure physiological relevance and predictive validity for in vivo outcomes. The assay conditions, including media composition and duration, are fully customized to align with your specific conjugate's mechanism of action.
Conjugate Characterization
Prior to all biological testing, the provided conjugate undergoes a mandatory quality control verification. We accurately determine its concentration using validated methods (e.g., UV-Vis spectroscopy) and assess its purity via analytical chromatography. This critical pre-characterization ensures that all subsequent potency data is normalized to the precise molar amount of the bioactive oligonucleotide payload, guaranteeing the accuracy and interpretability of dose-response relationships.
Dose-Response Treatment
Cells are treated with your conjugate across a multi-log, serial dilution in biologically relevant media, which may be serum-containing or serum-free based on the study design. This dose-response matrix is designed to capture the full dynamic range of activity, from no effect to maximal silencing. Crucially, cell viability is monitored in parallel using metabolic or membrane integrity assays to confirm that any observed gene modulation is a direct therapeutic effect and not an artifact of non-specific cytotoxicity.
Target Quantification
At empirically optimized time points post-treatment, typically ranging from 24 to 72 hours to capture both initial mRNA knockdown and subsequent protein depletion, cells are harvested. Target engagement is quantified at the RNA level using sensitive, sequence-specific RT-qPCR assays. For a direct functional readout, protein-level knockdown is validated via quantitative western blot analysis or ELISA, providing a comprehensive view of the conjugate's biological activity.
Data Modeling & Reporting
The raw quantification data (mRNA or protein levels) are rigorously analyzed. Our bioinformaticians fit the dose-response curves to a four-parameter logistic (4PL) regression model to calculate precise potency metrics, including IC50, IC90, and Hill slope values. You receive a comprehensive, interpretative report containing the calculated pharmacokinetic parameters, full statistical analysis, dose-response curves, and, when applicable, comparative benchmarking against internal or industry-standard reference compounds.
Publication Data
Journal: Molecular Therapy
DOI: 10.1016/j.ymthe.2019.06.009
IF: 12.0
Published: 2019
Results: This research investigates the potential of enhancing ASO therapies for hepatocellular carcinoma (HCC) through GalNAc conjugation, which targets the asialoglycoprotein receptor (ASGR) highly expressed on hepatocytes. The authors conducted comprehensive in vitro studies using HCC cell lines with varying ASGR levels and in vivo experiments in diethylnitrosamine-induced mouse models, demonstrating that GalNAc-conjugated ASOs exhibit significantly improved potency, 5 to 10-fold greater than unconjugated ASOs, even in tumors with reduced ASGR expression. Key findings include efficient gene knockdown, reduced tumor burden, and enhanced antitumor activity, validated through pharmacodynamic and efficacy assessments. Furthermore, the study utilized circulating tumor cells from HCC patients to confirm functional ASGR activity and ASO response, proposing a non-invasive method for patient stratification. These results underscore the clinical promise of GalNAc-ASOs as a targeted therapeutic strategy for HCC, leveraging receptor-mediated delivery to overcome limitations of conventional oligonucleotide treatments.
Applications
Metabolic Disease Research
We quantify the potency of GalNAc-siRNA conjugates targeting hepatic factors like PCSK9 or ANGPTL3, providing the IC50 data needed to optimize cholesterol-lowering and lipid-regulating therapies.
Neuromuscular Disorder Therapeutics
Our assays measure the exon-skipping efficiency of AOCs and peptide-ASO conjugates in muscle cell models, helping researchers develop effective treatments for conditions like Duchenne Muscular Dystrophy.
Precision Oncology Programs
We evaluate the potency of antibody-oligonucleotide conjugates designed to deliver toxic siRNAs or antisense payloads specifically to tumor cells, minimizing systemic exposure while maximizing intra-tumoral gene silencing.
Viral Infection Modeling
We assess the ability of conjugates to inhibit viral replication in primary cells. We measure the knockdown of viral transcripts (e.g., HBV pre-genomic RNA) to identify the most potent antiviral candidates.
Advantages
Holistic Potency Evaluation
We don't just measure RNA levels; we evaluate the entire delivery and action cycle. Our assays account for receptor binding, internalization, endosomal escape, and final target engagement, providing a complete picture of therapeutic performance.
High-Precision IC50 Determination
Our standardized protocols and automated liquid handling minimize technical variability. This results in highly reproducible dose-response curves with narrow confidence intervals, which is essential for differentiating between closely related lead candidates.
Multiplexed Readouts
We can simultaneously measure target knockdown and cell health in a single well. This "multiplexing" approach allows for the immediate identification of toxic sequences, ensuring that your potency data is not confounded by off-target cellular stress.
Validated Control Library
Every project includes access to our internal library of reference conjugates. Benchmarking your new candidate against industry-standard molecules provides critical context and validates the performance of our assay system.
Frequently Asked Questions
Customer Review
The depth of the technical report was impressive. Seeing the imaging data of the conjugate's endosomal escape helped us understand why one linker outperformed the others.
— By Manager, Bioanalytical Chemistry
We've tried several CROs, but CD BioGlyco's expertise in primary hepatocyte culture is unmatched. Their data gave us the confidence to move into NHP studies.
— By Dr. L.B., Senior Principal Researcher
The ddPCR data provided by CD BioGlyco was exceptionally clean. They helped us detect a 25% knockdown in a very low-abundance transcript that other labs had missed.
— By Dr. P.L., Associate Professor
Associated Services
Peptide-Therapeutic Oligonucleotide Delivery Service
Enhancing cellular penetration and tissue-specific targeting via high-affinity peptide ligands.
LNP-Therapeutic Oligonucleotide Delivery Service
State-of-the-art lipid nanoparticle formulation for the systemic delivery of mRNA and siRNA payloads.
PEG-Therapeutic Oligonucleotide Delivery Service
PEGylation strategies to enhance the pharmacokinetics and stability of therapeutic oligonucleotides.
CD BioGlyco is the industry leader in the functional validation of complex RNA conjugates. Our conjugate potency assay service provides the rigorous, high-resolution data necessary to transform chemical conjugates into viable clinical therapeutics. By bridging the gap between synthesis and biological effect, we empower our clients to make data-driven decisions that accelerate the discovery of life-changing medicines. Contact us!
Reference
- Kim, Y.; et al. Enhanced potency of GalNAc-conjugated antisense oligonucleotides in hepatocellular cancer models. Molecular Therapy. 2019, 27(9): 1547-1557. (Open Access)