7 research outputs found
Abstract 2894: XMT-1592, a site-specific Dolasynthen-based NaPi2b-targeted antibody-drug conjugate for the treatment of ovarian cancer and lung adenocarcinoma
No full textAbstract The Dolasynthen platform incorporates the highly potent anti-mitotic agent auristatin F-HPA (AF-HPA), with its associated DolaLock mechanism of controlled bystander effect, and enables the synthesis of antibody-drug conjugates (ADCs) with precise control of the drug-to-antibody ratio (DAR) and site-specific bioconjugation. XMT-1592 is a novel ADC comprised of an anti-NaPi2b antibody and Dolasynthen, conjugated in a site-specific manner to yield DAR 6. NaPi2b, also known as SLC34A2, is a transmembrane sodium-phosphate transporter that is broadly expressed on tumor cells in ovarian carcinoma, NSCLC lung adenocarcinoma and other tumor types. Recent studies have shown that NaPi2b expression is enriched in the EGFR and KRAS mutant subtypes of lung adenocarcinoma. Binding studies showed a specific, high-affinity interaction of XMT-1592 with NaPi2b that was not affected by conjugated Dolasynthen. XMT-1592 elicited potent and specific in vitro cytotoxicity against NaPi2b-expressing ovarian carcinoma cells. XMT-1592 exhibited potent and specific in vivo activity in NaPi2b-expressing tumor xenografts derived from ovarian carcinoma or lung adenocarcinoma. Consistent with the targeted delivery benefits of the ADC approach, XMT-1592 yielded high and sustained concentrations of AF-HPA to tumors but not normal tissues. To evaluate the benefits of site-specific bioconjugation of Dolasynthen, we conducted in vitro and in vivo comparisons of XMT-1592 to a stochastically conjugated version of the ADC. XMT-1592 had improved in vivo activity, pharmacokinetics, and clinical pathology relative to its stochastic counterpart. Taken together, these results support XMT-1592 as a development candidate for the treatment of NaPi2b-expressing tumors. Citation Format: Shawn Fessler, Anouk Dirksen, Scott D. Collins, Ling Xu, Winnie Lee, Jason Wang, Ron Eydelloth, Elena Ter-Ovanesyen, Jeffrey Zurita, Elizabeth Ditty, Barrett Nehilla, Susan Clardy, Susan Clardy, Tyler Carter, Kenneth Avocetien, Mark Nazzaro, Nam Le, Kalli C. Catcott, Alex Uttard, Bingfan Du, Chen-Ni Chin, Rebecca Mosher, Kelly Slocum, Liuliang Qin, David Lee, Dorin Toader, Marc Damelin, Timothy B. Lowinger. XMT-1592, a site-specific Dolasynthen-based NaPi2b-targeted antibody-drug conjugate for the treatment of ovarian cancer and lung adenocarcinoma [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 2894
Stimuli-Responsive Polymer-Antibody Conjugates via RAFT and Tetrafluorophenyl Active Ester Chemistry
No full textHighly efficient polymer-antibody conjugations were demonstrated
via a tetrafluorophenyl active ester. A well-defined diblock copolymer
was synthesized by reversible addition–fragmentation chain
transfer (RAFT) polymerization with a temperature-responsive block,
poly(N-isopropylacrylamide), and a block of N,N-dimethylacrylamide and 2,3,5,6-tetrafluorophenyl
acrylate active ester. The polymer was conjugated to anti-p24 IgG
antibody with about 100% efficiency in as little as 2 h at room temperature
in a pH 10.8 buffer. The temperature-responsiveness of the polymer
was conferred to the polymer–antibody conjugates after conjugation.
The conjugates bound p24 antigen specifically and with binding efficiency
comparable to native antibodies. Thus, the active ester diblock copolymer
can facilitate the synthesis of temperature-responsive bioconjugates,
which may be promising reagents for immunoassays, bioseparations,
and specimen-enrichment applications
Peptide-Conjugated Quantum Dots Activate Neuronal Receptors and Initiate Downstream Signaling of Neurite Growth
No full textQuantum dots (QDs) could serve as fluorescent scaffolds for effecting specific physiological and pharmacological responses in cells. Here,
we conjugate the peptide ligand βNGF to QD surfaces, and confirm surface modification and single QD nanostructure using AFM. We show
that βNGF-QDs retain bioactivity, activate TrkA receptors, and initiate neuronal differentiation in PC12 cells. Receptor-evoked activity of QD-immobilized ligands has wide-ranging implications for the development of molecular tools and therapeutics targeted at understanding and
regulating cell function
A Stimuli-Responsive, Binary Reagent System for Rapid Isolation of Protein Biomarkers
No full textMagnetic
microbeads exhibit rapid separation characteristics and
are widely employed for biomolecule and cell isolations in research
laboratories, clinical diagnostics assays, and cell therapy manufacturing.
However, micrometer particle diameters compromise biomarker recognition,
which leads to long incubation times and significant reagent demands.
Here, a stimuli-responsive binary reagent system is presented that
combines the nanoscale benefits of efficient biomarker recognition
and the microscale benefits of rapid magnetic separation. This system
comprises magnetic nanoparticles and polymer–antibody (Ab)
conjugates that transition from hydrophilic nanoscale reagents to
microscale aggregates in response to temperature stimuli. The binary
reagent system was benchmarked against Ab-labeled Dynabeads in terms
of biomarker isolation kinetics, assay speed, and reagent needs. Surface
plasmon resonance (SPR) measurements showed that polymer conjugation
did not significantly alter the Ab’s binding affinity or kinetics.
ELISA analysis showed that the unconjugated Ab, polymer–Ab
conjugates, and Ab-labeled Dynabeads exhibited similar equilibrium
dissociation constants (Kd), ∼2
nM. However, the binary reagent system isolated HIV p24 antigen from
spiked serum specimens (150 pg/mL) much more quickly than Dynabeads,
which resulted in shorter binding times by tens of minutes, or about
30–50% shorter overall assay times. The binary reagent system
showed improved performance because the Ab molecules were not conjugated
to large, solid microparticle surfaces. This stimuli-responsive binary
reagent system illustrates the potential advantages of nanoscale reagents
in molecule and cell isolations for both research and clinical applications
