1
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Vasalou C, Proia TA, Kazlauskas L, Przybyla A, Sung M, Mamidi S, Maratea K, Griffin M, Sargeant R, Urosevic J, Rosenbaum AI, Yuan J, Aluri KC, Ramsden D, Hariparsad N, Jones RDO, Mettetal JT. Quantitative evaluation of trastuzumab deruxtecan pharmacokinetics and pharmacodynamics in mouse models of varying degrees of HER2 expression. CPT Pharmacometrics Syst Pharmacol 2024. [PMID: 38532525 DOI: 10.1002/psp4.13133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2023] [Revised: 02/02/2024] [Accepted: 03/08/2024] [Indexed: 03/28/2024] Open
Abstract
Trastuzumab deruxtecan (T-DXd; DS-8201; ENHERTU®) is a human epithelial growth factor receptor 2 (HER2)-directed antibody drug conjugate (ADC) with demonstrated antitumor activity against a range of tumor types. Aiming to understand the relationship between antigen expression and downstream efficacy outcomes, T-DXd was administered in tumor-bearing mice carrying NCI-N87, Capan-1, JIMT-1, and MDA-MB-468 xenografts, characterized by varying HER2 levels. Plasma pharmacokinetics (PK) of total antibody, T-DXd, and released DXd and tumor concentrations of released DXd were evaluated, in addition to monitoring γΗ2AX and pRAD50 pharmacodynamic (PD) response. A positive relationship was observed between released DXd concentrations in tumor and HER2 expression, with NCI-N87 xenografts characterized by the highest exposures compared to the remaining cell lines. γΗ2AX and pRAD50 demonstrated a sustained increase over several days occurring with a time delay relative to tumoral-released DXd concentrations. In vitro investigations of cell-based DXd disposition facilitated the characterization of DXd kinetics across tumor cells. These outputs were incorporated into a mechanistic mathematical model, utilized to describe PK/PD trends. The model captured plasma PK across dosing arms as well as tumor PK in NCI-N87, Capan-1, and MDA-MB-468 models; tumor concentrations in JIMT-1 xenografts required additional parameter adjustments reflective of complex receptor dynamics. γΗ2AX longitudinal trends were well characterized via a unified PD model implemented across xenografts demonstrating the robustness of measured PD trends. This work supports the application of a mechanistic model as a quantitative tool, reliably projecting tumor payload concentrations upon T-DXd administration, as the first step towards preclinical-to-clinical translation.
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Affiliation(s)
- Christina Vasalou
- Clinical Pharmacology & Safety Sciences, Waltham, Massachusetts, USA
| | | | | | - Anna Przybyla
- AstraZeneca Research & Development, Waltham, Massachusetts, USA
| | - Matthew Sung
- AstraZeneca Research & Development, Waltham, Massachusetts, USA
| | | | - Kim Maratea
- Clinical Pharmacology & Safety Sciences, Waltham, Massachusetts, USA
| | - Matthew Griffin
- Clinical Pharmacology & Safety Sciences, Waltham, Massachusetts, USA
| | | | | | - Anton I Rosenbaum
- Integrated Bioanalysis, Clinical Pharmacology & Safety Sciences, South San Francisco, California, USA
| | - Jiaqi Yuan
- Integrated Bioanalysis, Clinical Pharmacology & Safety Sciences, South San Francisco, California, USA
| | - Krishna C Aluri
- AstraZeneca Research & Development, Waltham, Massachusetts, USA
| | - Diane Ramsden
- AstraZeneca Research & Development, Waltham, Massachusetts, USA
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2
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White MJ, Cheatham L, Wen S, Scarfe G, Cidado J, Reimer C, Hariparsad N, Jones RDO, Drew L, McGinnity DF, Vasalou C. A PKPD Case Study: Achieving Clinically Relevant Exposures of AZD5991 in Oncology Mouse Models. AAPS J 2023; 25:66. [PMID: 37380821 DOI: 10.1208/s12248-023-00836-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Accepted: 06/13/2023] [Indexed: 06/30/2023] Open
Abstract
Capturing human equivalent drug exposures preclinically is a key challenge in the translational process. Motivated by the need to recapitulate the pharmacokinetic (PK) profile of the clinical stage Mcl-1 inhibitor AZD5991 in mice, we describe the methodology used to develop a refined mathematical model relating clinically relevant concentration profiles to efficacy. Administration routes were explored to achieve target exposures matching the clinical exposure of AZD5991. Intravenous infusion using vascular access button (VAB) technology was found to best reproduce clinical target exposures of AZD5991 in mice. Exposure-efficacy relationships were evaluated, demonstrating that dissimilar PK profiles result in differences in target engagement and efficacy outcomes. Thus, these data underscore the importance of accurately ascribing key PK metrics in the translational process to enable clinically meaningful predictions of efficacy.
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Affiliation(s)
- Michael J White
- AstraZeneca Research and Development Boston: AstraZeneca R&D Boston, Waltham, Massachusetts, USA.
| | - Letitia Cheatham
- AstraZeneca Research and Development Boston: AstraZeneca R&D Boston, Waltham, Massachusetts, USA
| | - Shenghua Wen
- AstraZeneca Research and Development Boston: AstraZeneca R&D Boston, Waltham, Massachusetts, USA
| | - Graeme Scarfe
- AstraZeneca Research and Development Boston: AstraZeneca R&D Boston, Waltham, Massachusetts, USA
| | - Justin Cidado
- AstraZeneca Research and Development Boston: AstraZeneca R&D Boston, Waltham, Massachusetts, USA
| | - Corinne Reimer
- AstraZeneca Research and Development Boston: AstraZeneca R&D Boston, Waltham, Massachusetts, USA
| | - Niresh Hariparsad
- AstraZeneca Research and Development Boston: AstraZeneca R&D Boston, Waltham, Massachusetts, USA
| | - Rhys D O Jones
- AstraZeneca Research and Development Boston: AstraZeneca R&D Boston, Waltham, Massachusetts, USA
| | - Lisa Drew
- AstraZeneca Research and Development Boston: AstraZeneca R&D Boston, Waltham, Massachusetts, USA
| | - Dermot F McGinnity
- AstraZeneca Research and Development Boston: AstraZeneca R&D Boston, Waltham, Massachusetts, USA
| | - Christina Vasalou
- AstraZeneca Research and Development Boston: AstraZeneca R&D Boston, Waltham, Massachusetts, USA
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3
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Michaelides IN, Collie GW, Börjesson U, Vasalou C, Alkhatib O, Barlind L, Cheung T, Dale IL, Embrey KJ, Hennessy EJ, Khurana P, Koh CM, Lamb ML, Liu J, Moss TA, O'Neill DJ, Phillips C, Shaw J, Snijder A, Storer RI, Stubbs CJ, Han F, Li C, Qiao J, Sun DQ, Wang J, Wang P, Yang W. Discovery and Optimization of the First ATP Competitive Type-III c-MET Inhibitor. J Med Chem 2023. [PMID: 37343272 DOI: 10.1021/acs.jmedchem.3c00401] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/23/2023]
Abstract
Recent clinical reports have highlighted the need for wild-type (WT) and mutant dual inhibitors of c-MET kinase for the treatment of cancer. We report herein a novel chemical series of ATP competitive type-III inhibitors of WT and D1228V mutant c-MET. Using a combination of structure-based drug design and computational analyses, ligand 2 was optimized to a highly selective chemical series with nanomolar activities in biochemical and cellular settings. Representatives of the series demonstrate excellent pharmacokinetic profiles in rat in vivo studies with promising free-brain exposures, paving the way for the design of brain permeable drugs for the treatment of c-MET driven cancers.
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Affiliation(s)
| | - Gavin W Collie
- Discovery Sciences, R&D, AstraZeneca, Cambridge CB4 0WG, United Kingdom
| | - Ulf Börjesson
- Discovery Sciences, R&D, AstraZeneca, 43183 Mölndal, Sweden
| | - Christina Vasalou
- DMPK, Oncology R&D, AstraZeneca, Boston, Waltham, Massachusetts 02451, United States
| | - Omar Alkhatib
- Discovery Sciences, R&D, AstraZeneca, Cambridge CB4 0WG, United Kingdom
| | - Louise Barlind
- Discovery Sciences, R&D, AstraZeneca, 43183 Mölndal, Sweden
| | - Tony Cheung
- Bioscience, Oncology R&D, AstraZeneca, Boston, Waltham, Massachusetts 02451, United States
| | - Ian L Dale
- Discovery Sciences, R&D, AstraZeneca, Cambridge CB4 0WG, United Kingdom
| | - Kevin J Embrey
- Discovery Sciences, R&D, AstraZeneca, Cambridge CB4 0WG, United Kingdom
| | - Edward J Hennessy
- Medicinal Chemistry, Oncology R&D, AstraZeneca, Boston, Waltham, Massachusetts 02451, United States
| | - Puneet Khurana
- Discovery Sciences, R&D, AstraZeneca, Cambridge CB4 0WG, United Kingdom
| | - Cheryl M Koh
- Bioscience, Oncology R&D, AstraZeneca, Boston, Waltham, Massachusetts 02451, United States
| | - Michelle L Lamb
- Computational Chemistry, Oncology R&D, AstraZeneca, Boston, Waltham, Massachusetts 02451, United States
| | - Jianming Liu
- Discovery Sciences, R&D, AstraZeneca, 43183 Mölndal, Sweden
| | - Thomas A Moss
- Medicinal Chemistry, Oncology R&D, AstraZeneca, Cambridge, CB4 0WG, United Kingdom
| | - Daniel J O'Neill
- Discovery Sciences, R&D, AstraZeneca, Cambridge CB4 0WG, United Kingdom
| | | | - Joseph Shaw
- Discovery Sciences, R&D, AstraZeneca, Cambridge CB4 0WG, United Kingdom
| | - Arjan Snijder
- Discovery Sciences, R&D, AstraZeneca, 43183 Mölndal, Sweden
| | - R Ian Storer
- Discovery Sciences, R&D, AstraZeneca, Cambridge CB4 0WG, United Kingdom
| | | | - Fujin Han
- Pharmaron Beijing Co., Ltd., 6 Taihe Road BDA, 100176 Beijing, People's Republic of China
| | - Chengzhi Li
- Pharmaron Beijing Co., Ltd., 6 Taihe Road BDA, 100176 Beijing, People's Republic of China
| | - Jingchuan Qiao
- Pharmaron Beijing Co., Ltd., 6 Taihe Road BDA, 100176 Beijing, People's Republic of China
| | - Dong-Qing Sun
- Pharmaron Beijing Co., Ltd., 6 Taihe Road BDA, 100176 Beijing, People's Republic of China
| | - Jingwen Wang
- Pharmaron Beijing Co., Ltd., 6 Taihe Road BDA, 100176 Beijing, People's Republic of China
| | - Peng Wang
- Pharmaron Beijing Co., Ltd., 6 Taihe Road BDA, 100176 Beijing, People's Republic of China
| | - Wenzhen Yang
- Pharmaron Beijing Co., Ltd., 6 Taihe Road BDA, 100176 Beijing, People's Republic of China
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Vasalou C, Harding J, Jones RDO, Hariparsad N, McGinnity DF. Interspecies evaluation of a physiologically based pharmacokinetic model to predict the biodistribution dynamics of dendritic nanoparticles. PLoS One 2023; 18:e0285798. [PMID: 37195991 DOI: 10.1371/journal.pone.0285798] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Accepted: 05/02/2023] [Indexed: 05/19/2023] Open
Abstract
The exposure of a dendritic nanoparticle and its conjugated active pharmaceutical ingredient (API) was determined in mouse, rat and dog, with the aim of investigating interspecies differences facilitating clinical translation. Plasma area under the curves (AUCs) were found to be dose proportional across species, while dose normalized concentration time course profiles in plasma, liver and spleen were superimposable in mouse, rat and dog. A physiologically based pharmacokinetic (PBPK) model, previously developed for mouse, was evaluated as a suitable framework to prospectively capture concentration dynamics in rat and dog. The PBPK model, parameterized either by considering species-specific physiology or using alternate scaling methods such as allometry, was shown to capture exposure profiles across species. A sensitivity analysis highlighted API systemic clearance as a key parameter influencing released API levels. The PBPK model was utilized to simulate human exposure profiles, which overlaid dose-normalized data from mouse, rat and dog. The consistency in measured interspecies exposures as well as the capability of the PBPK model to simulate observed dynamics support its use as a powerful translational tool.
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Affiliation(s)
- Christina Vasalou
- Oncology R&D, AstraZeneca, Boston, Massachusetts, United States of America
| | | | | | - Niresh Hariparsad
- Oncology R&D, AstraZeneca, Boston, Massachusetts, United States of America
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5
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Beaumont K, Pike A, Davies M, Savoca A, Vasalou C, Harlfinger S, Ramsden D, Ferguson D, Hariparsad N, Jones O, McGinnity D. ADME and DMPK considerations for the discovery and development of antibody drug conjugates (ADCs). Xenobiotica 2022; 52:770-785. [PMID: 36314242 DOI: 10.1080/00498254.2022.2141667] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The therapeutic concept of antibody drug conjugates (ADCs) is to selectively target tumour cells with small molecule cytotoxic drugs to maximise cell kill benefit and minimise healthy tissue toxicity.An ADC generally consists of an antibody that targets a protein on the surface of tumour cells chemically linked to a warhead small molecule cytotoxic drug.To deliver the warhead to the tumour cell, the antibody must bind to the target protein and in general be internalised into the cell. Following internalisation, the cytotoxic agent can be released in the endosomal or lysosomal compartment (via different mechanisms). Diffusion or transport out of the endosome or lysosome allows the cytotoxic drug to express its cell-killing pharmacology. Alternatively, some ADCs (e.g. EDB-ADCs) rely on extracellular cleavage releasing membrane permeable warheads.One potentially important aspect of the ADC mechanism is the 'bystander effect' whereby the cytotoxic drug released in the targeted cell can diffuse out of that cell and into other (non-target expressing) tumour cells to exert its cytotoxic effect. This is important as solid tumours tend to be heterogeneous and not all cells in a tumour will express the targeted protein.The combination of large and small molecule aspects in an ADC poses significant challenges to the disposition scientist in describing the ADME properties of the entire molecule.This article will review the ADC landscape and the ADME properties of successful ADCs, with the aim of outlining best practice and providing a perspective of how the field can further facilitate the discovery and development of these important therapeutic modalities.
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Affiliation(s)
- Kevin Beaumont
- Drug Metabolism and Pharmacokinetics, Early Oncology Research and Development, Cambridge, UK
| | - Andy Pike
- Drug Metabolism and Pharmacokinetics, Early Oncology Research and Development, Cambridge, UK
| | - Michael Davies
- Drug Metabolism and Pharmacokinetics, Early Oncology Research and Development, Cambridge, UK
| | - Adriana Savoca
- Drug Metabolism and Pharmacokinetics, Early Oncology Research and Development, Cambridge, UK
| | - Christina Vasalou
- Drug Metabolism and Pharmacokinetics, Early Oncology Research and Development, AstraZeneca, Boston, MA, USA
| | - Steffi Harlfinger
- Drug Metabolism and Pharmacokinetics, Early Oncology Research and Development, Cambridge, UK
| | - Diane Ramsden
- Drug Metabolism and Pharmacokinetics, Early Oncology Research and Development, AstraZeneca, Boston, MA, USA
| | - Douglas Ferguson
- Drug Metabolism and Pharmacokinetics, Early Oncology Research and Development, AstraZeneca, Boston, MA, USA
| | - Niresh Hariparsad
- Drug Metabolism and Pharmacokinetics, Early Oncology Research and Development, AstraZeneca, Boston, MA, USA
| | - Owen Jones
- Drug Metabolism and Pharmacokinetics, Early Oncology Research and Development, Cambridge, UK
| | - Dermot McGinnity
- Drug Metabolism and Pharmacokinetics, Early Oncology Research and Development, Cambridge, UK
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6
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Proia T, Urosevic J, Vasalou C, Sargeant R, Griffin M, Yuan J, Rosenbaum AI, Mettetal J. Abstract 1141: Pharmacokinetic and pharmacodynamic evaluation of human tumor xenograft models treated upon administration of trastuzumab deruxtecan. Cancer Res 2022. [DOI: 10.1158/1538-7445.am2022-1141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
Introduction: Trastuzumab deruxtecan (T-DXd) is an antibody-drug conjugate comprised of an anti-HER2 antibody, a cleavable tetrapeptide-based linker, and a cytotoxic topoisomerase I inhibitor approved for the treatment of HER2 positive metastatic breast and gastric cancer. T-DXd has demonstrated antitumor activity in both HER2+ and HER2-low patient populations.
Methods: To establish exposure profiles of T-DXd and link with tumor biomarker changes, we administered a single IV dose of T-DXd at 10 mg/kg in human tumor xenograft models representing HER2-positive (NCI-N87; nude) and Her2-low (Capan-1; NOD-SCID) and collected tumor and plasma from 6 h to 336 h post dose. We measured tumor volume in addition to total ADC, total antibody, and free payload in the plasma and assessed biomarkers related to DNA damage in the tumor by western blot (WB) and immunohistochemistry (IHC).
Results: In HER2+ NCI-N87 tumor-bearing mice, T-DXd plasma AUC was 342.6ug/ml*day and T1/2 was 3.5 days, while in the HER2-low Capan-1 tumor-bearing mice, T-DXd plasma AUC was 297.2ug/ml*day and T1/2 was 1.4 days. Plasma exposures of free payload (DXd) were less than 1 ng/mL. Both models responded to T-DXd, demonstrating regression over the 14 day study (T/C =-6.08%, NCI-N87 and -96.1%, Capan-1). In NCI-N87, we observed rapid and sustained increases in gamma H2AX (gH2AX), with a 3.5-fold increase in % positive staining by IHC (H-score p<0.001) with gH2AX foci as early as 24h post treatment, and sustained out to 96h. Western blot analysis and quantification of gH2AX revealed a 4.3-fold increase at 48h (p<0.0001), which was sustained out to 96h. Further, we observed significant increases in pRAD50 at 24h (3.6-fold increase by IHC, H-score p<0.001) which was sustained out to 96h. In Capan-1, we observed more diffuse staining of gH2AX and non-significant 1.4-fold increase in gH2AX at 24h. pRAD50 increases were delayed in the Capan-1 model with a 2.8-fold increase observed at 48h and sustained out to 168h post treatment.
Conclusions: Plasma exposure of T-DXd in NCI-N87 tumor bearing mice was prolonged compared to Capan-1, possibly due to mouse strain differences. The increased systemic exposure resulted in more rapid and sustained DNA damage as measured by gH2AX and pRAD50 in the NCI-N87 tumor compared to Capan-1. This profile suggests exploration of combinations with DNA damage response inhibitors to inform design of dose and schedule of combination therapy may be warranted.
Citation Format: Theresa Proia, Jelena Urosevic, Christina Vasalou, Rebecca Sargeant, Matthew Griffin, Jiaqi Yuan, Anton I. Rosenbaum, Jerome Mettetal. Pharmacokinetic and pharmacodynamic evaluation of human tumor xenograft models treated upon administration of trastuzumab deruxtecan [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1141.
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7
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Vasalou C, Ferguson D, Li W, Muse V, Gibbons FD, Sonzini S, Zhang G, Pop-Damkov P, Gangl E, Balachander SB, Wen S, Schuller AG, Puri S, Mazza M, Ashford M, Fretland AJ, McGinnity DF, Jones RDO. Quantitative Evaluation of Dendritic Nanoparticles in Mice: Biodistribution Dynamics and Downstream Tumor Efficacy Outcomes. Mol Pharm 2022; 19:172-187. [PMID: 34890209 DOI: 10.1021/acs.molpharmaceut.1c00715] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A physiologically based pharmacokinetic model was developed to describe the tissue distribution kinetics of a dendritic nanoparticle and its conjugated active pharmaceutical ingredient (API) in plasma, liver, spleen, and tumors. Tumor growth data from MV-4-11 tumor-bearing mice were incorporated to investigate the exposure/efficacy relationship. The nanoparticle demonstrated improved antitumor activity compared to the conventional API formulation, owing to the extended released API concentrations at the site of action. Model simulations further enabled the identification of critical parameters that influence API exposure in tumors and downstream efficacy outcomes upon nanoparticle administration. The model was utilized to explore a range of dosing schedules and their effect on tumor growth kinetics, demonstrating the improved antitumor activity of nanoparticles with less frequent dosing compared to the same dose of naked APIs in conventional formulations.
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Affiliation(s)
- Christina Vasalou
- Oncology R&D, AstraZeneca, Boston, Massachusetts 02451, United States
| | - Douglas Ferguson
- Oncology R&D, AstraZeneca, Boston, Massachusetts 02451, United States
| | - Weimin Li
- Pharmaceutical Sciences, R&D, AstraZeneca, Macclesfield SK10 2NA, U.K
| | - Victorine Muse
- Novo Nordisk Foundation Center for Protein Research, Copenhagen 2200, Denmark
| | | | - Silvia Sonzini
- Pharmaceutical Sciences, R&D, AstraZeneca, Macclesfield SK10 2NA, U.K
| | - Guangnong Zhang
- Dicerna Pharmaceuticals, Inc, Lexington, Massachusetts 02421, United States
| | - Petar Pop-Damkov
- Takeda Pharmaceuticals, Cambridge, Massachusetts 02139, United States
| | - Eric Gangl
- Oncology R&D, AstraZeneca, Boston, Massachusetts 02451, United States
| | | | - Shenghua Wen
- Oncology R&D, AstraZeneca, Boston, Massachusetts 02451, United States
| | - Alwin G Schuller
- Oncology R&D, AstraZeneca, Boston, Massachusetts 02451, United States
| | - Sanyogitta Puri
- Pharmaceutical Sciences, R&D, AstraZeneca, Macclesfield SK10 2NA, U.K
| | - Mariarosa Mazza
- Pharmaceutical Sciences, R&D, AstraZeneca, Macclesfield SK10 2NA, U.K
| | - Marianne Ashford
- Pharmaceutical Sciences, R&D, AstraZeneca, Macclesfield SK10 2NA, U.K
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8
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Abstract
Antibody drug conjugates (ADCs) represent novel anti-cancer modalities engineered to specifically target and kill tumor cells expressing corresponding antigens. Due to their large size and their complex kinetics, these therapeutic agents often face heterogeneous distributions in tumors, leading to large untargeted regions that escape therapy. We present a modeling framework which includes the systemic distribution, vascular permeability, interstitial transport, as well as binding and payload release kinetics of ADC-therapeutic agents in mouse xenografts. We focused, in particular, on receptor dynamics such as endocytic trafficking mechanisms within cancer cells, to simulate their impact on tumor mass shrinkage upon ADC administration. Our model identified undesirable tumor properties that can impair ADC tissue homogeneity, further compromising ADC success, and explored ADC design optimization scenarios to counteract upon such unfavorable intrinsic tumor tissue attributes. We further demonstrated the profound impact of cytotoxic payload release mechanisms and the role of bystander killing effects on tumor shrinkage. This model platform affords a customizable simulation environment which can aid with experimental data interpretation and the design of ADC therapeutic treatments.
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Affiliation(s)
- Christina Vasalou
- Advanced Quantitative Sciences, Novartis, Cambridge, MA, United States of America
| | - Gabriel Helmlinger
- Advanced Quantitative Sciences, Novartis, Cambridge, MA, United States of America
| | - Bruce Gomes
- Advanced Quantitative Sciences, Novartis, Cambridge, MA, United States of America
- * E-mail:
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9
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Vasalou C, Herzog E, Henson M. Multicellular model for intercellular synchronization in circadian neural networks. Biophys J 2011; 101:12-20. [PMID: 21723810 PMCID: PMC3127187 DOI: 10.1016/j.bpj.2011.04.051] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2010] [Revised: 03/22/2011] [Accepted: 04/18/2011] [Indexed: 12/22/2022] Open
Abstract
We developed a multicellular model characterized by a high degree of heterogeneity to investigate possible mechanisms that underlie circadian network synchronization and rhythmicity in the suprachiasmatic nucleus (SCN). We populated a two-dimensional grid with 400 model neurons coupled via γ-aminobutyric acid (GABA) and vasoactive intestinal polypeptide (VIP) neurotransmitters through a putative Ca(2+) mediated signaling cascade to investigate their roles in gene expression and electrical firing activity of cell populations. As observed experimentally, our model predicted that GABA would affect the amplitude of circadian oscillations but not synchrony among individual oscillators. Our model recapitulated experimental findings of decreased synchrony and average periods, loss of rhythmicity, and reduced circadian amplitudes as VIP signaling was eliminated. In addition, simulated increases of VIP reduced periodicity and synchrony. We therefore postulated a physiological range of VIP within which the system is able to produce sustained and synchronized oscillations. Our model recapitulated experimental findings of diminished amplitudes and periodicity with decreasing intracellular Ca(2+) concentrations, suggesting that such behavior could be due to simultaneous decrease of individual oscillation amplitudes and population synchrony. Simulated increases in Cl(-) levels resulted in increased Cl(-) influx into the cytosol, a decrease of inhibitory postsynaptic currents, and ultimately a shift of GABA-elicited responses from inhibitory to excitatory. The simultaneous reduction of IPSCs and increase in membrane resting potential produced GABA dose-dependent increases in firing rates across the population, as has been observed experimentally. By integrating circadian gene regulation and electrophysiology with intracellular and intercellular signaling, we were able to develop the first (to our knowledge) multicellular model that allows the effects of clock genes, electrical firing, Ca(2+), GABA, and VIP on circadian system behavior to be predicted.
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Affiliation(s)
- Christina Vasalou
- Department of Chemical Engineering, University of Massachusetts, Amherst, Massachusetts
| | - Erik D. Herzog
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri
| | - Michael A. Henson
- Department of Chemical Engineering, University of Massachusetts, Amherst, Massachusetts
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10
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Vasalou C, Herzog ED, Henson MA. Small-world network models of intercellular coupling predict enhanced synchronization in the suprachiasmatic nucleus. J Biol Rhythms 2009; 24:243-54. [PMID: 19465701 DOI: 10.1177/0748730409333220] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The suprachiasmatic nucleus (SCN) of the hypothalamus is a multioscillator system that drives daily rhythms in mammalian behavior and physiology. Based on recent data implicating vasoactive intestinal polypeptide (VIP) as the key intercellular synchronizing agent, we developed a multicellular SCN model to investigate the effects of cellular heterogeneity and intercellular connectivity on circadian behavior. A 2-dimensional grid was populated with 400 model cells that were heterogeneous with respect to their uncoupled rhythmic behavior (intrinsic and damped pacemakers with a range of oscillation periods) and VIP release characteristics (VIP producers and nonproducers). We constructed small-world network architectures in which local connections between VIP producing cells and their 4 nearest neighbors were augmented with random connections, resulting in long-range coupling across the grid. With only 10% of the total possible connections, the small-world network model was able to produce similar phase synchronization indices as a mean-field model with VIP producing cells connected to all other cells. Partial removal of random connections decreased the synchrony among neurons, the amplitude of VIP and cAMP response element binding protein oscillations, the mean period of intrinsic periods across the population, and the percentage of oscillating cells. These results indicate that small-world connectivity provides the optimal compromise between the number of connections and control of circadian amplitude and synchrony. This model predicts that small decreases in long-range VIP connections in the SCN could have dramatic effects on period and amplitude of daily rhythms, features commonly described with aging.
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Affiliation(s)
- Christina Vasalou
- Department of Chemical Engineering, University of Massachusetts, Amherst, Massachusetts 01003, USA
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