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Description
A specific subgroup of breast cancer patients carry a fingerprint molecule named Her2New receptor which is used for many years as a target for specific anticancer therapy. Her2 antibodies effectively block tumour cells development and prevent tumour growth. While effective initially, cancer cells develop metabolic mechanisms to escape therapeutic inhibition and a very valuable therapeutic tool is as such lost. We identified two goals: to manipulate the cancer cells such as to become again responsive to the biological therapy targeting Her2New receptor; to augment distribution of intended drug such as to limit drug delivery to tumour tissue and limit systemic toxicity associated with non-targeted distribution. The team will produce and test polymeric chains that are capable to change their spatial configuration in relation with the pH of the medium. As such these chains will form a complex mycelia in neutral pH and will act like sponge absorbing the chemical compound needed to be delivered. We will use the specific behaviour of tumour tissue that will induce an acidic environment. .The new approach we develop will also be available for other types of tumours, as all of them share the acidic environment generated by rapid, uncontrolled multiplication of cancer cells.The group has also experience in the introduction of new drugs on the market and they will benefit from the cooperation with the Romanian partners by using a mechanism of feedback in production and in vitro studies that will allow rapid adjustments of nano-carriers structure.
Summary of project results
Cancer is a major contributor to disease burden worldwide. Cancer incidence and mortality is rapidly growing, and female breast cancer surpasses lung cancer as the most commonly diagnosed cancer. New data supports the urgent need for comprehensive cancer prevention and new treatment to effectively reduce the global burden of breast cancer. One breast cancer subtype, overexpressing Her2 receptors - called Her2 positive, is frequently associated with invasion and metastasis. Trastuzumab is the first clinically used humanized monoclonal antibody used in targeted treatment of this subtype. The toxicity of Her2 targeted therapies and the development of resistance to treatment challenge clinicians and researchers to search for novel and efficient treatment options. The resistance to trastuzumab involves modulation of signaling pathways that prevent biological effects of trastuzumab. Modifying these pathways should prevent the appearance of resistance and allow for restoration of response to treatment, allowing patients to further benefit from trastuzumab treatment. While numerous alternatives are researched, our challenge was to restore the efficacy of long term treatment with trasutzumab using functionalized nanocarriers. These nanosize particles will use trastuzumab for targeting cancer cells overexpressi ng Her2 receptor, and should be loaded with an inhibitor of the Axl receptor expressed on the cancer cell surface.
The project started by identifying a very efficient pH-dependent release nanostructure. We have tested three type of micelles and we have selected·.for further investigations the one that is most stable at the physiological pH {7.6 -7:4) but in the same time with most efficient release at pH 7.2. We have focused our research on pH 7:''l sensitive nanostructures due to the fact that primary tumors {where pH · is very acidic) are· surgically removed while metastases and the remaining tissue adjacent to primary tumors have a pH closer to the physiological one. Up to 40% of women develop local recurrence after surgery, despite apparently tumor-free margins. In addition to ''the physical-chemically characterization, the release have been also investigated in cancer cell cultures. The selected micelles have been functionalized by linking trastuzumab for targeting the cancer cells. The biological effects of functionalized micelles have been tested by various techniques in several Her2 positive and negative cancer cell lines and in laboratory mice. Animal experiments have been performed according with the European legislation on the protection of animals used for scientific research. Functionalized micelles have been loaded with Axl inhibitor and investigate biological effect using sensitive and induced trastuzumab resistant clones.
Using a Her2 positive cancer cell line, linking trastuzumab to micelles enhance therapeutical effects compared to free trastuzumab. Extending investigations to demonstrate the potentiated therapeutical effect of linked trastuzumab to micelles, we have used additional cell lines, both human Her2 positive and human and murine Her2 negative, as negative controls. Her2 negative cell lines have a low expression of Her2 receptor, while Her2 positive overexpress this receptor. As expected, free trastuzumab impaired cell viability only in the Her2 positive and responsive to treatment cell lines while did not reduce cell viability of tested Her2 negative cell lines. To our surprise, linked trastuzumab to micelles significantly impaired cell viability of particularly Her2 negative selected cell lines. Our overall results, demonstrates that trastuzumab functionalized micelles reduce metastasis, the process of spreading cancer by forming metastases in distal organs. This may open the possibility that these particular patients which have chemotherapy as the only systemic therapeutic alternative to benefit from the new therapy option. The results on Her2 positive investigations revealed a double mechanism of resistance, by increasing Axl expression and by decreasing Her2 expression. The release of Axl inhibitor loaded into functionalized micelles restores the therapeutically effects of trastuzumab in resistant clone.
Summary of bilateral results
Working in partnership is a complex and challenging activity requiring new skills for adapting new and controversial ideas and being able to negotiate and compromise in the group. Numerous meetings and brainstorming sessions made us better in recognizing how to make a step forward and to be able to identify a good solution and a dead end in research. We wrote together 3 more application for research and better understood how to divide work between partners and join together in assessing results. This project made us able to better estimate each partner''s strong points and how to mix these qualities together in a major project. We were exposed to criticism from our partners and by doing it we were all able to better evaluate our work and discuss steps in developing new experiments and analyse the results.