Andrew T. Millican

Conversion of highly malignant colon cancer from an aggressive to a controlled disease by oral administration of a metalloproteinase inhibitor

In this study, we describe the activity of CT1746, an orally-active synthetic MMP inhibitor that has a greater specificity for gelatinase A, gelatinase B and stromelysin than for interstitial collagenase and matrilysin, in a nude mouse model that better mimics the clinical development of human colon cancer. The model is constructed by surgical orthotopic implantation (SOI) of histologically-intact tissue of the metastatic human colon tumor cell line Co-3. Animals were gavaged with CT1746 twice a day at 100 mg/kg for 5 days after the SOI of Co-3 for 43 days. In this model CT1746 significantly prolonged the median survival time of the tumor-bearing animals from 51 to 78 days. Significant efficacy of CT1746 was observed on primary tumor growth (32% reduction in mean tumor area at day 36), total spread and metastasis (6/20 treated animals had no detectable spread and metastasis at autopsy compared to 100% incidence of secondaries in control groups). Efficacy of CT1746 could also be seen on reducing tumor spread and metastasis to individual organ sites such as the abdominal wall, cecum and lymph nodes compared to vehicle and untreated controls. We conclude that chronic administration of a peptidomimetic MMP inhibitor via the oral route is feasible and results in inhibition of solid tumor growth, spread and metastasis with increase in survival in this model of human cancer, thus converting aggressive cancer to a more controlled indolent disease.

The in vivo release of 90Y from cyclic and acyclic ligand-antibody conjugates

Yttrium binding ligands DOTA, caDTPA and CT-DTPA were each conjugated to monoclonal antibody B72.3, labelled with 90Y and injected into mice in order to assess the in vivo inertness of the antibody-linked 90Y-ligand complexes. Levels of 90Y in femur shafts of the DOTA-B72.3 mice were low, being approximately 7 and 44%, respectively, of levels in the femur shafts of the caDTPA-B72.3 and CT-DTPA-B72.3 treated mice. This finding demonstrates the greater inertness and by implication the greater suitability for immunotherapy of the DOTA-90Y complex.

Synthesis of a kinetically stable yttrium-90 labelled macrocycle–antibody conjugate

Lysine is a precursor for the synthesis of an aminobutyl C-functionalised tetra-azacyclododecane tetra-acid which has been linked to B72.3 antibody and may be labelled with 90Y to form a kinetically stable complex of potential use in radioimmunotherapy.

Towards tumour imaging with indium-111 labelled macrocycle–antibody conjugates

C-Functionalised triazacyclododecane and triazacyclononane triacid macrocycles have been covalently attached to a monoclonal antibody and may be labelled with 111In to form kinetically inert radiolabelled complexes.

Potent and selective inhibitors of gelatinase-a 1. hydroxamic acid derivatives

Abstract A series of hydroxamic acid derivatives were prepared. By introducing aromatic substituents at the P1′ and P3′ positions highly potent gelatinase-A inhibitors, which possess a high degree of selectivity over collagenase and stromelysin, were obtained. These inhibitors may be of therapeutic value in the control of tumour metastasis.

Potent and selective inhibitors of gelatinase-A 2. carboxylic and phosphonic acid derivatives

Abstract A series of zinc binding groups was introduced into a pseudopeptide sequence containing aromatic groups in the P1′ position in order to obtain selective inhibitors of gelatinase-A. Carboxylic acid and phosphonic acid groups provided the most potent inhibitors

Towards tumour targeting with copper-radiolabelled macrocycle–antibody conjugates: synthesis, antibody linkage, and complexation behaviour

A set of four tetra-azamacrocyclic ligands bearing aminomethylphenyl substituents have been prepared and may be attached to a monoclonal antibody via an intermediate thiol-specific vinylpyridine linker molecule. The resultant conjugates may be efficiently radiolabelled with 64Cu or 67Cu at pH 4 to minimise non-specific protein binding, and the copper labelled antibody-conjugate is stable with respect to copper loss in vivo. The forward rate of copper binding has been optimised through a kinetic analysis using stopped-flow spectrophotometry. In succinate buffer, anionic copper species Cu(succ)22–(log β= 4.35) and HCu(succ)2–(log β= 9.64) are the kinetically significant copper species in the pH range 3.6–5.6.

Synthesis of C- and N-functionalised derivatives of 1,4,7-triazacyclononane-1,4,7-triyltriacetic acid (NOTA), 1,4,7,10-tetra-azacyclododecane-1,4,7,10-tetrayltetra-acetic acid (DOTA), and diethylenenetriaminepenta-acetic acid (DTPA): bifunctional complexing agents for the derivatisation of antibodies

Using (2S)-lysine as a precursor, the syntheses of aminobutyl derivatives of 1,4,7-triazacyclononane, 1,4,7,10-tetra-azacyclododecane, and 3-azapentane-1,5-diamine are described. Transformation into their reactive maleimide derivatives is described and alternative strategies for synthesising the title complexing agents involving nitrogen functionalisation are defined.

Towards tumour targeting with copper-radiolabelled macrocycle–antibody conjugates

Tetra-aza-macrocycles covalently attached to a monoclonal antibody may be efficiently radiolabelled with 64Cu or 67Cu at pH 4, minimising non-specific binding to the protein, giving a kinetically stable conjugate in vivo.

Antibody labelling with functionalised cyclam macrocycles

Functionalised ‘cyclam’ macrocyclic ligands have been selectively attached to thiol residues on a monoclonal antibody and form kinetically inert complexes with Cu2+ and TcV.