Marika Nestor's projects on head and neck tumour targeting

Use of radio-immunotargeting to improve diagnostics and therapy of head and neck squamous cell carcinoma

Diana Spiegelberg, Anna-Karin Haylock, Anja C. Mortensen, Sara Lundsten, Marika Nestor

In this project, we aim to improve diagnostics and therapy of head and neck squamous cell carcinoma (HNSCC), by the use of radio-immunotargeting. We identify and characterize different promising antigens as new molecular targets in this setting. Novel tumour-targeting molecules are then developed and evaluated. Finally, the targeting molecules are radio-labelled with various radionuclides, and the radio-conjugates are optimized and assessed for diagnostic and therapeutic potential.

Possible novel antigens of interest for radionuclide targeting of HNSCC

We are assessing the possibility of targeting several promising novel therapeutic targets for radionuclide targeting. We are studying the density and distribution of primarily, but not limited to, different splice variants of CD44. In cases where surface markers differentially expressed in subpopulations are identified, subpopulations are evaluated for differences in e.g. proliferation, migration and radioresistance in vitro.

Development and characterisation of suitable targeting molecules for radio-immunotargeting in HNSCC

This is a translational project with the established goal of ultimately evaluating the most promising conjugate in the clinic. In the initial stages we mainly focus on developing conjugates for molecular imaging. Currently, we are assessing several different formats targeting CD44v6, such as antibody single-chain variable fragments (scFv), antigen-binding fragments (Fab fragments) and bivalent Fab Mini-antibodies (functionally equivalent to Fab2 fragments), as well as a promising peptide towards CD44v6, and a promising antibody towards EGFRvIII. We also assess different radionuclides and labelling methods in order to form our targeting radioconjugates, and evaluate the binding interactions and cellular processing of the conjugates in tumour cells both in vitro and in vivo.

Improving cancer therapy by combining radio-immunotherapy and p53 therapy

Anja C. Mortensen, Diana Spiegelberg, Sara Lundsten, Marika Nestor

The main objective for this project is to combine two cancer therapies, radio-immunotherapy and p53 therapy, to improve treatment outcomes and prolong patient survival. Ionizing radiation has been shown to induce p53-dependent Mdm2 gene transcription, eventually resulting in degradation of p53, leading to prevention of apoptosis. However, blocking the Mdm2/p53 interaction actively prevents this degradation, and could therefore improve the effectiveness of radio-immunotherapy.

The effect of radiolabelled conjugates in combination with p53/MdM2 therapeutic peptides in vitro

Several tumour associated antigens are investigated, and suitable targeting agents towards these targets are then selected. So far, we have focused on EGFRvIII, EGFR and CD44v6 as tumour targets, and antibodies or antibody fragments binding to one of these antigens as the targeting molecules. Selected molecules are then assessed for radiolabelling of suitable therapeutic radionuclides. We use radionuclides of interest for therapy, such as 177Lu and 131I, but we are also assessing more diagnostic radionuclides such as 111In, in case we obtain high synergistic effects with the combination therapies.

Cytotoxicity of peptides targeting the MdM2/p53 interaction is assessed in order to find suitable concentrations for combination therapy. Cytotoxicity of selected radio-conjugates of different specific activity is assessed in the same way. Finally, the cytotoxicity of p53 therapy, radio-immunotherapy, and the combination of the two in monolayer cell assays (where applicable) and in tumour spheroids is assessed.

Evaluation of the most promising combinations in vivo

For the most suitable combinations of radio-conjugates and p53 peptides, we plan to move on to therapy studies in tumour bearing mice. The optimal doses and specific activity for peptides and radio-conjugates will be evaluated, as well as in vivo kinetics, tumour uptake and uptake in normal tissue. Therapy experiments, in which mice will receive a) no treatment, b) p53 therapy, c) radio-immunotherapy, and d) p53 therapy and radio-immunotherapy, will then be performed.

Tools for the characterization of heterogeneous protein interactions

Hanna Björkelund, Sina Bondza, João Encarnação, Jos Buijs, Jonas Stenberg, Karl Andersson

Proteins are biological macromolecules that are essential for life. They serve as structural components in the cells and are involved in almost all biological processes. Their function can be catalytical (enzymes), DNA triggering (transcription factors) or involved in the immune response (antibodies), to mention a few possibilities. In most cases, proteins typically interact with other molecules and proteins in order to perform their tasks. The characterization of protein interactions is therefore an important part of cell-biology research.

A biosensor can detect how proteins bind to cells

The aim of the project is to improve the tools for characterization of protein – cell interactions, both from a measurement point of view and an analysis point of view. We have developed a novel class of biosensor that is capable of detecting how proteins bind to cells in real-time, and are now focusing on data analysis tools for interpretation of the acquired binding traces.

The majority of current biomolecular interaction analysis is based on simple models and assumptions, like 1:1 interactions (L + T ↔ LT). The heterogeneous cell surface contradicts such assumptions, and we therefore believe that a better description of protein cell interactions can lead to important improvements of how biological processes are explained and understood.