Dual-targeting Agent Research Articles

Molecular modelling, synthesis, cytotoxicity and anti-tumour mechanisms of 2-aryl-6-substituted quinazolinones as dual-targeted anti-cancer agents: Development of novel dual-targeted anti-cancer agents

Molecular modelling, synthesis, cytotoxicity and anti-tumour mechanisms of 2-aryl-6-substituted quinazolinones as dual-targeted anti-cancer agents: Development of novel dual-targeted anti-cancer agents

Molecular Targeting of Ultrasonographic Contrast Agent for Detection of Head and Neck Squamous Cell Carcinoma

To investigate the feasibility of ultrasonographic (US) imaging of head and neck cancer with targeted contrast agents both in vitro and in vivo. We hypothesize that conjugation of microbubble contrast agent to tumor-specific antibodies may improve US detection of head and neck squamous cell carcinoma (HNSCC). Preclinical blinded assessment of anti-EGFR and anti-CD147 microbubble contrast agents for US imaging of HNSCC. Animal study. Immunodeficient mice. Injection of targeted microbubbles. Microbubble uptake in tumors as detected by US. In vitro assessment of anti-epidermal growth factor receptor (EGFR) and anti-CD147-targeted microbubbles in 6 head and neck cancer cell lines yielded a 6-fold improvement over normal dermal fibroblasts (P < .001). Binding of targeted agents had a positive correlation to both epidermal growth factor receptor (EGFR) (R(2) = 0.81) and CD147 (R(2) = 0.72) expression among all cell lines. In vivo imaging of flank tumors in nude mice (N = 8) yielded enhanced resolution of anti-EGFR-and anti-CD147-targeted microbubble agents over IgG control (P < .001), while dual-targeted contrast agents offered enhanced imaging over single-targeted contrast agents (P = .02 and P = .05, respectively). In a blinded in vivo assessment, targeted contrast agents increased intratumoral enhancement of flank tumors over controls. Targeted US contrast agents to both EGFR and CD147 were 100% sensitive and 87% specific in the detection of flank tumors. This preclinical study demonstrates feasibility of using molecular US to target HNSCC for contrast-enhanced imaging of HNSCC tumor in vivo.

Abstract 2974: Combating breast cancer brain metastasis by targeting Src family kinases

Abstract Background: Among 1.3 million women diagnosed with breast cancer every year, 10-16% will develop brain metastases. The median survival of patients with brain metastases is less than one year. A most challenging problem is no effective treatment for patients with refractory metastatic breast cancer to the brain. Therefore, novel and effective therapeutic approaches are urgently needed for this population. Recently, our retrospective analyses revealed a significant up-regulation of Src family kinase (SFK) in breast cancer brain metastasis lesions compared with primary tumors. Additionally, HER2-overexpressing breast cancers with Src activation have a higher incidence of brain metastasis. Thus, we hypothesize that activation of SFK plays a critical role in promoting breast cancer brain metastasis. Aims and Methodology: The major aims of this project are: 1) study the role of Src activation in breast cancer brain metastasis; 2) investigate the pre-clinical efficacy of combination Src inhibitor and HER2-targeting therapy Lapatinib in treatment of brain metastasis. We used HER2-overexpressing breast cancer cell line models, in vitro assays of metastasis-properties, and in vivo brain metastasis mouse model (intracarotid artery injection) to test our hypothesis. Results and Conclusions: Src activity is up-regulated in both brain-seek cells lines and human brain metastasis tumors when compared to either parental cells lines or primary breast cancers respectively. To test the role of Src activation in brain metastasis, we established stable cells lines with constitutive-activation of Src. The Src activation enhanced the tumor cell trans-blood brain barrier migration in vitro. Src activation in cells led to a higher brain metastasis incidence in vivo after intracarotid artery injection. We treated Src-activated brain metastasis in vivo with a Src inhibitor saracatinib, a drug under Phase II clinical trial. This Src-targeting treatment decreased the overall incidence of brain metastasis. Combining sarcatinib with EGFR-HER2 dual-targeting agent lapatinib further prolonged the overall survival of tumor bearing mice and significantly inhibited both micro- and macro-metastasis. In summary, novel SFK targeting regimens may be developed as promising therapies for breast cancer patients with brain metastasis. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 2974. doi:1538-7445.AM2012-2974

Combined therapy of temozolomide and ZD6474 (vandetanib) effectively reduces glioblastoma tumor volume through anti-angiogenic and anti-proliferative mechanisms

Currently, clinically available options for treating glioblastoma (GBM) are quite limited, and there is a clear need to develop novel treatment strategies that can more effectively manage tumors. Here, we present a combination treatment of temozolomide (TMZ), a blood-brain barrier penetrating DNA alkylating agent, and ZD6474 (vandetanib), a VEGFR2 and EGFR dual-targeting anti-angiogenic agent, as a novel treatment strategy for GBM. In a U-87MG orthotopic xenograft model, the combination treatment provided a marked 94% tumor volume reduction. This reduction was greater than that achieved by monotherapy of either agent, and was correlated with a statistically significant reduction in microvessel density (CD31+ cells) and proliferation (PCNA+ cells). These results confirm the necessity to target angiogenesis in addition to utilizing cytotoxic approaches, and provide the rationale for application of TMZ + ZD6474 combination therapy for treating GBM patients in the clinical setting.

Dual-Targeting for the Elimination of Cancer Cells with Increased Selectivity

Here we review recombinant proteins with a capability for dual-targeting. These molecules address two different antigens on the same tumor cell and therefore are called “dual-targeting agents”. By virtue of binding a chosen pair of antigens on the malignant cell, preferential binding to antigen double-positive over single-positive cells can be achieved when both are present in the same environment. Therapeutic effects of such agents are based on different modes of action: (1) They can act as pro-apoptotic agents or by inhibiting pro-survival signals; (2) The dual recognition moiety can be fused to effector-domains, such as bacterial toxins or other drugs, leading to the generation of bispecific antibody-drug conjugates (ADCs); (3) Dual-targeting agents can further be used to redirect an effector-cell to the tumor. A new generation of scFv-derived fusion proteins are the tandem single chain triplebodies (sctbs), which carry two scFv binding sites for antigens on the tumor cell plus a third, specific for a trigger molecule on an effector cell. The ability of preferential or selective targeting of antigen double-positive over single-positive cells opens attractive new perspectives for the use of dual-targeting agents in cancer therapy, and possibly also for the treatment of certain inflammatory and autoimmune disorders.

Dual-Targeted Agent Cabozantinib Shows Early Activity in Common Solid Tumors &amp; Bone Metastases

Dual-Targeted Agent Cabozantinib Shows Early Activity in Common Solid Tumors &amp; Bone Metastases

Comparison of In Vitro Activities of Fluoroquinolone-Like 2,4- and 1,3-Diones

Bacterial resistance presents a difficult issue for fluoroquinolone treatment of bacterial infections. In previous work, we reported that 8-methoxy-quinazoline-2,4-diones are active against quinolone-resistant mutants of Escherichia coli. Here, we demonstrate the activity of a representative 8-methoxy-quinazoline-2,4-dione against quinolone-resistant gyrases. Furthermore, 8-methoxy-quinazoline-2,4-dione and other diones are shown to inhibit Staphylococcus aureus gyrase and topoisomerase IV with similar degrees of efficacy, suggesting that the diones might act as dual-targeting agents against S. aureus.

Dual targeting improves microbubble contrast agent adhesion to VCAM-1 and P-selectin under flow

To improve ultrasound contrast agents targeted to the adhesion molecules P-selectin and VCAM-1 for the purpose of molecular imaging of atherosclerotic plaques, perfluorocarbon-filled phospholipid microbubble contrast agents were coupled by a polyethylene glycol–biotin–streptavidin bridge with mAb MVCAM.A(429), a sialyl Lewis x polymer (PAA-sLe x), or both (dual). Approximately three hundred thousand antibody molecules were coupled to the surface of each microbubble. Recombinant mouse P-selectin and/or VCAM-1 coated on flow chambers showed saturation of binding at approximately 15 ng/μl, resulting in 800 and 1200 molecules/µm 2 for P-selectin and VCAM-1, respectively. Dual substrates coated with equal concentrations of P-selectin and VCAM-1 had site densities between 50 and 60% of single substrates. When microbubbles were perfused through flow chambers at 5 × 10 6 microbubbles/ml (wall shear stress from 1.5 to 6 dyn/cm 2) dual-targeted microbubbles adhered almost twice as efficiently as single-targeted microbubbles at 6 dyn/cm 2. The present study suggests that dual-targeted contrast agents may be useful for atherosclerotic plaque detection at physiologically relevant shear stresses.

Integration of Ligand and Structure-Based Virtual Screening for the Identification of the First Dual Targeting Agent for Heat Shock Protein 90 (Hsp90) and Tubulin

We describe the discovery of a novel indazole-based scaffold that represents the "first-in-class" dual Hsp90/tubulin binding compound. Individual known ligands for both targets shared similar 3',4',5'-trimethoxyphenyl cores, and from this it was hypothesized that application of an integrated ligand and structure-based virtual screening (VS) workflow could yield a single scaffold with dual binding affinity. Following validation of the VS protocol, we successfully identified a novel dual inhibitor, sourced from a commercial screening collection of 160 000 compounds.

Dual-targeted Contrast Agent for US Assessment of Tumor Angiogenesis in Vivo

To develop and validate a dual-targeted ultrasonographic (US) imaging agent with microbubbles (MBs) that attaches to both vascular endothelial growth factor (VEGF) receptor 2 (VEGFR2) and alpha(v)beta(3) integrin and to compare the US imaging signal obtained from dual-targeted MBs (MB(D)) with that from single-targeted MBs (MB(S)) in a murine model of tumor angiogenesis. Animal protocols were approved by the institutional Administrative Panel on Laboratory Animal Care. Single- and dual-targeted US imaging agents were prepared by attaching anti-VEGFR2, anti-alpha(v)beta(3) integrin, or both antibodies to the shell of perfluorocarbon-filled MBs. Binding specificities of targeted MBs compared with isotype-matched immunoglobulin G-labeled control MBs (MB(C)) and nontargeted nonlabeled MBs (MB(N)) were tested with VEGFR2-positive and alpha(v)beta(3) integrin-positive cells (mouse SVR cells) and control cells (mouse 4T1 cells). In vivo imaging signals of contrast material-enhanced US by using anti-VEGFR2-targeted MBs (MB(V)), anti-alpha(v)beta(3) integrin-targeted MBs (MB(I)), MB(D), and MB(C) were quantified in 49 mice bearing SK-OV-3 tumors (human ovarian cancer). Tumor tissue was stained for VEGFR2, alpha(v)beta(3) integrin, and CD31. Attachment of MB(D) to SVR cells (mean, 0.74 MBs per cell +/- 0.05 [standard deviation]) was significantly higher than attachment to 4T1 cells (mean, 0.04 +/- 0.03), and attachment to SVR cells was higher for MB(D) than for MB(V) (mean, 0.58 +/- 0.09), MB(I) (mean, 0.42 +/- 0.21), MB(C) (mean, 0.11 +/- 0.13), and MB(N) (mean, 0.01 +/- 0.01) (P < .05). Imaging signal in the murine tumor angiogenesis model was significantly higher (P < .001) for MB(D) (mean, 16.7 +/- 7.2) than for MB(V) (mean, 11.3 +/- 5.7), MB(I) (mean, 7.8 +/- 5.3), MB(C) (mean, 2.8 +/- 0.9), and MB(N) (mean, 1.1 +/- 0.4). Immunofluorescence confirmed expression of VEGFR2 and alpha(v)beta(3) integrin on tumor vasculature. Dual-targeted contrast-enhanced US directed at both VEGFR2 and alpha(v)beta(3) integrin improves in vivo visualization of tumor angiogenesis in a human ovarian cancer xenograft tumor model in mice. http://radiology.rsnajnls.org/cgi/content/full/248/3/936/DC1.

Small-colony mutants of Staphylococcus aureus allow selection of gyrase-mediated resistance to dual-target fluoroquinolones.

Fluoroquinolones acting equally through DNA gyrase and topoisomerase IV in vivo are considered desirable in requiring two target mutations for emergence of resistant bacteria. To investigate this idea, we have studied the response of Staphylococcus aureus RN4220 to stepwise challenge with sparfloxacin, a known dual-target agent, and with NSFQ-105, a more potent sulfanilyl fluoroquinolone that behaves similarly. First-step mutants were obtained with both drugs but only at the MIC. These mutants exhibited distinctive small-colony phenotypes and two- to fourfold increases in MICs of NSFQ-105, sparfloxacin, and ciprofloxacin. No changes were detected in the quinolone resistance-determining regions of the gyrA, gyrB, grlA, or grlB gene. Quinolone-induced small-colony mutants shared the delayed coagulase response but not the requirement for menadione, hemin, or thymidine characteristic of small-colony variants, a subpopulation of S. aureus that is often defective in electron transport. Second-step mutants selected with NSFQ-105 had gyrA(S84L) alterations; those obtained with sparfloxacin carried a gyrA(D83A) mutation or a novel gyrB deletion (DeltaRKSAL, residues 405 to 409) affecting a trypsin-sensitive region linking functional domains of S. aureus GyrB. Each mutation was associated with four- to eightfold increases in MICs of NSFQ-105 and sparfloxacin, but not of ciprofloxacin, which we confirm targets topoisomerase IV. The presence of wild-type grlB-grlA gene sequences in second-step mutants excluded involvement of topoisomerase IV in the small-colony phenotype. Growth revertants retaining mutant gyrA or gyrB alleles were quinolone susceptible, indicating that resistance to NSFQ-105 and sparfloxacin was contingent on the small-colony mutation. We propose that small-colony mutations unbalance target sensitivities, perhaps through altered ATP or topoisomerase levels, such that gyrase becomes the primary drug target. Breaking of target parity by genetic or physiological means eliminates the need for two target mutations and provides a novel mechanism for stepwise selection of quinolone resistance.