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Studies have shown that some peptides and small molecules can induce non IgE-mediated anaphylactoid reactions through mast cell activation. Upon activation, mast cells degranulate and release vasoactive and proinflammatory mediators, from cytoplasmic granules into the extracellular environment which can induce a cascade of severe adverse reactions. This study describes a lead optimization strategy to select NaV1.7 inhibitor peptides that minimize acute mast cell degranulation (MCD) toxicities. Various in vitro, in vivo, and PKPD models were used to screen candidates and guide peptide chemical modifications to mitigate this risk. Anesthetized rats dosed with peptides demonstrated treatment-related decreases in blood pressure and increases in plasma histamine concentrations which were reversible with a mast cell stabilizer, supporting the MCD mechanism. In vitro testing in rat mast cells with NaV1.7 peptides demonstrated a concentration-dependent increase in histamine. Pharmacodynamic modeling facilitated establishing an in vitro to in vivo correlation for histamine as a biomarker for blood pressure decline via the MCD mechanism. These models enabled assessment of structure-activity relationship (SAR) to identify substructures that contribute to peptide-mediated MCD. Peptides with hydrophobic and cationic characteristics were determined to have an elevated risk for MCD, which could be reduced or avoided by incorporating anionic residues into the protoxin II scaffold. Our analyses support that in vitro MCD assessment in combination with PKPD modeling can guide SAR to improve peptide lead optimization and ensure an acceptable early in vivo tolerability profile with reduced resources, cycle time, and animal use. [ABSTRACT FROM AUTHOR]

The chemo enzymatic synthesis of two G (sub M3)-derived reagents and their use in the panning of a phage-displayed human single-chain Fv (scFv) antibody library derived from the blood of cancer patients is described. The result is a significant step toward effective immunotherapies for the treatment of cancer.

The chiral complexes of three of the most commonly utilized and commercially available alkyllithium reagents, n-Butyllithium (BuLi), sec-BuLi and tert-BuLi, were isolated and characterized. The compounds are analogous to alkoxysilyl aggregates and phenyl glycidol derived amide. An n-BuLi alkyllithium/lithium containing aggregate was crystallized and characterized. This aggregate possesses a non-crystallographic 2-fold axis of symmetry if the alkyl group is not considered. The best selectivity was observed in a chiral Li amide ligand from an O-methyl-alpha amino alcohol.

Peptide hybrids (phybrids) comprisingcovalently linked peptidehormones can leverage independent biological pathways for additiveor synergistic metabolic benefits. PEGylation of biologics offersenhanced stability, duration, and reduced immunogenicity. These twomodalities can be combined to produce long-acting therapeutics withdual pharmacology and enhanced efficacy. Compound 10iscomposed of an exenatide (AC2993) analogue, AC3174, and an amylinomimetic,davalintide (AC2307), with an intervening 40 kD PEG moiety. It displayeddose-dependent and prolonged efficacy for glucose control and bodyweight reduction in rodents with superior in vitroand in vivoactivities compared to those of a side-chainPEGylated phybrid 6. In diet-induced obese (DIO) rats,the weight-loss efficacy of 10was similar to that ofa combination of PEG-parents 3and 4. Asingle dose of 10elicited sustained body weight reductionin DIO rats for at least 21 days. Compound 10’sterminal half-life of ∼27 h should translate favorably to weeklydosing in humans. [ABSTRACT FROM AUTHOR]

Selective antitumor chemotherapy can be achieved by using antibody-drug conjugates that recognize surface proteins upregulated in cancer cells. One such receptor is integrin α3β1, which is overexpressed on malignant melanoma, prostate carcinoma, and glioma cells. We previously identified a human single-chain Fv antibody (scFv), denoted Pan10, specific for integrin α3β1 that is internalized by human pancreatic cancer cells. Herein, we describe the chemical introduction of reactive thiol groups onto Pan10, the specific conjugation of the modified scFv to maleimide-derivatized analogs of the potent cytotoxic agent duocarmycin SA, and the properties of the resultant conjugates. Our findings provide evidence that Pan10-drug conjugates maintain the internalizing capacity of the parent scFv and are cytotoxic at nanomolar concentrations. Our Pan10-drug conjugates may be promising candidates for targeted chemotherapy of malignant diseases associated with overexpression of integrin α3β1. [Copyright &y& Elsevier]

Inhibitor cystine knot peptides, derived from venom, have evolved to block ion channel function but are often toxic when dosed at pharmacologically relevant levels in vivo . The article describes the design of analogues of ProTx-II that safely display systemic in vivo blocking of Na v 1.7, resulting in a latency of response to thermal stimuli in rodents. The new designs achieve a better in vivo profile by improving ion channel selectivity and limiting the ability of the peptides to cause mast cell degranulation. The design rationale, structural modeling, in vitro profiles, and rat tail flick outcomes are disclosed and discussed.

The tetrahydrofuran tetrasolvated dimeric lithium dienolate derived from 2,2,7,7-tetramethyloctan-3,6-dione is characterized in the solid state by X-ray diffraction analysis and in solution by diffusion NMR. This dienolate was reacted with tropanone to yield two new products that are also described.

A chiral enolate aggregate 1 containing a lithium enolate and a chiral lithium amide was systematically investigated by various NMR techniques. (1)H and (13)C DOSY at 25 and -78 degrees C provide its solution structure, aggregation number, and formula weight. Multiple 2D (6)Li NMR techniques, such as (6)Li-(6)Li EXSY, (6)Li-(1)H HOESY, were utilized to investigate its stereochemical structure. The configuration of the enolate in complex 1 was confirmed by (6)Li-(1)H HOESY and trapping with TMS-Cl. A unique (6)Li-(1)H coupling through the Li-N-C-H network was observed. This scalar coupling was corroborated by (6)Li-(1)H HMQC, deuterium labeling experiments, and selective (1)H decoupling (6)Li NMR. The stereostructure of 1 provides a model for the origin of enantioselectivity of chiral lithium amide-induced enolate addition reactions.

Selective antitumor chemotherapy can be achieved by using antibody-drug conjugates that recognize surface proteins upregulated in cancer cells. One such receptor is integrin alpha3beta1, which is overexpressed on malignant melanoma, prostate carcinoma, and glioma cells. We previously identified a human single-chain Fv antibody (scFv), denoted Pan10, specific for integrin alpha3beta1 that is internalized by human pancreatic cancer cells. Herein, we describe the chemical introduction of reactive thiol groups onto Pan10, the specific conjugation of the modified scFv to maleimide-derivatized analogs of the potent cytotoxic agent duocarmycin SA, and the properties of the resultant conjugates. Our findings provide evidence that Pan10-drug conjugates maintain the internalizing capacity of the parent scFv and are cytotoxic at nanomolar concentrations. Our Pan10-drug conjugates may be promising candidates for targeted chemotherapy of malignant diseases associated with overexpression of integrin alpha3beta1.

Expression of legumain, a novel asparaginyl endopeptidase, in tumors was identified from gene expression profiling and tumor tissue array analysis. Legumain was demonstrated in membrane-associated vesicles concentrated at the invadopodia of tumor cells and on cell surfaces where it colocalized with integrins. Legumain was demonstrated to activate progelatinase A. Cells overexpressing legumain possessed increased migratory and invasive activity in vitro and adopted an invasive and metastatic phenotype in vivo, inferring significance of legumain in tumor invasion and metastasis. A prodrug strategy incorporating a legumain-cleavable peptide substrate onto doxorubicin was developed. The prototype compound, designated legubicin, exhibited reduced toxicity and was effectively tumoricidal in vivo in a murine colon carcinoma model.

Overexpression of the cell-surface glycosphingolipid G(M3) is associated with a number of different cancers, including those of the skin, colon, breast, and lung. Antibodies against the G(M3) epitope have potential application as therapeutic agents in the treatment of these cancers. We describe the chemoenzymatic synthesis of two G(M3)-derived reagents and their use in the panning of a phage-displayed human single-chain Fv (scFv) antibody library derived from the blood of cancer patients. Three scFv-phage clones, GM3A6, GM3A8, and GM3A15, were selected for recombinant expression and were characterized using BIAcore and flow cytometry. BIAcore measurements using the purified, soluble scFvs yielded dissociation constants (K(d)) ranging from 4.2 x 10(-7) to 2.1 x 10(-5) M. Flow cytometry was used to evaluate the ability of each scFv to discriminate between normal human cells (human dermal fibroblast, HDFa), melanoma cells (HMV-1, M21, and C-8161), and breast cancer cells (BCM-1, BCM-2, and BMS). GM3A6 displayed cross-reactivity with normal cells, as well as tumor cells, and GM3A15 possessed little or no binding activity toward any of the cell lines tested. However, GM3A8 bound to five of the six tumor cell lines and showed no measurable reactivity against the HDFa cells. Hence, we have demonstrated that a synthetic G(M3) panning reagent can be used to isolate a fully human scFv that is highly specific for native G(M3) on the surface of tumor cells. The result is a significant step toward effective immunotherapies for the treatment of cancer.