Gunnar Schulte

Diverse signaling systems are attractive targets for anti-cancer therapy, one of which is the WNT/Frizzled signaling system, where secreted WNT proteins activate Frizzled receptors driving cancer cell proliferation, migration and invasion. The WNT/Frizzled signaling systems is of particular interest in pancreatic cancer carrying a mutation in the gene RNF43, which directly amplifies FZD signaling. This opens the opportunity for a precision medicine approach and our recent work on the first small molecules inhibiting Frizzleds validates this hypothesis.My research team has investigated Frizzled transduction mechanisms for more than fifteen years and our recent progress in pharmacology and structural biology (cryogenic electron microscopy, CryoEM), enables us now to understand molecular details of FZD activation, how they contribute to oncogenesis and how they can be targeted pharmacologically. In a combined biochemical, pharmacological and biophysical approach, we will further detail mechanisms of receptor activation, pathway initiation and signal specification to engage in a mechanism-based and structure-guided drug discovery process. The combination of receptor pharmacology, novel genetically encoded biosensors, in silico ligand docking, molecular dynamics simulations and a structure-based approach aiming to obtain high resolution information of Frizzleds in complex with ligands or intracellular binding proteins will provide novel insights into FZDs as a drug target.

Some tumors are dependent on an overactive signaling pathway where WNT proteins activate Frizzled surface receptors in the tumor cells. The WNT/Frizzled signaling cascade controls survival and cell division in tumor cells and thus contributes to tumor growth. Among other things, rectal, pancreatic, skin and breast tumors show increased activity of WNT/Frizzled signals. Based on our new research findings that it is actually possible to develop small molecule drugs that directly affect Frizzled, we here propose various pharmacological approaches to slow down WNT/Frizzled dependent cell division and metastasis and thus create new treatment options for cancer. With newly developed methodology, we will study how Frizzled surface receptors are activated in tumors. By better understanding the activation mechanisms, we will be able to fight back and reduce FZD activation with specific drugs. We combine basic research into receptor activation with drug development. The new substances that are identified will be tested in various relevant, preclinical cancer models and further developed towards possible clinical use. The idea is to create new drugs through a mechanism-based and structure-driven process that reduces overactive Frizzled signaling in tumors such as FZD5 in pancreatic cancer and FZD7 in colon cancer. With the proposed experiments, we will increase the understanding of the regulation of tumor-causing WNT and Frizzled signals in different tumor forms. A better understanding will also open up new points of attack for therapy. In addition, we now have the opportunity to create drugs that directly affect Frizzled receptors. Such substances have been sought after for decades but the methodology to produce them was lacking. This first step in the development of substances that affect Frizzleds will enable a new therapeutic strategy for cancer therapy. The substances will both be important for cancer treatment as well as for advanced preclinical research around Frizzleds.

Frizzleds (FZD1-10) belong to the class F of the G protein-coupled receptor (GPCR) superfamily and play a key role in the signal transduction of secreted lipoglycoproteins of the Wingless-Int1 (WNT) family. In embryonal development, WNT signaling governs essential processes such as cellular differentiation, polarization, and migration, while in the adult, WNT signaling is involved in tissue homeostasis. Abnormal WNT and FZD signaling is related to cancer, fibrosis, arthritis, and Alzheimer’s disease. Upon WNT binding, FZDs pair with their co-receptors low-density lipoprotein receptor-related protein (LRP) 5/6 and initiate the formation of a large protein complex at the membrane, the signalosome. Signalosome formation ultimately leads to stabilization of the transcriptional cofactor β-catenin by disruption of the β-catenin-destruction complex. Due to the complexity of WNT signaling pathways, many questions remain unanswered on a molecular level, e.g. the stoichiometry of the signalosome or interaction parameters and surfaces between FZDs and their coreceptors. Furthermore, FZDs were shown to exhibit large conformational changes, typical to other GPCRs, upon ligand binding and it is currently not clear, whether and how these FZD dynamics are involved in FZD signaling. The proposed project is divided into three work packages. The first and main objective aims to form a coherent theory of FZDs in WNT signaling by integrating the concepts of signalosome formation and FZD dynamics. To this end, we will develop BRET biosensors to interrogate the protein-protein interactions between FZDs and LRPs in presence and absence of WNTs. For these experiments, we will create CRISPR-Cas9 edited cells lacking endogenous expression of respective proteins. By using additional tools, such as oncogenic FZD mutants, surrogate WNT peptides, conformational biosensors, and positive allosteric FZD modulators, we intend to characterize the FZD-LRP complex formation that initiates signalosome formation and to unravel the role of FZD dynamics in WNT signal transduction. In another work package, we intend to characterize the interaction between FZDs and other WNT-binding co-receptors, such as RO1/2, RYK, and PTK7 with similar methods. These proteins are known to play a role in WNT signaling, but currently, direct evidence for interactions between these proteins and FZDs is lacking due to unsuitable assay readouts. Lastly, we will investigate if FZDs interact with receptor-activity modifying proteins (RAMPs) and whether a possible interaction affects FZD signaling either directly or e.g. by modulating FZD trafficking in the cell.

Some tumors are dependent on an overactive signaling pathway where WNT proteins activate Frizzled surface receptors in the tumor cells. The WNT/Frizzled signaling cascade controls survival and cell division in tumor cells and thus contributes to tumor growth. Among other things, rectal, pancreatic, skin and breast tumors show increased activity of WNT/Frizzled signals. Based on our new research findings that it is actually possible to develop small molecule drugs that directly affect Frizzled, we here propose different pharmacological approaches to slow down WNT/Frizzled dependent cell division and metastasis and thus create new treatment options for cancer. With newly developed methodology, we will study in detail how Frizzled surface receptors are activated. By better understanding the activation mechanisms, we will be able to fight back and reduce FZD activation with specific drugs. We combine basic research into receptor activation with drug development. The new substances that are identified will be tested in various relevant, preclinical cancer models and further developed towards possible clinical use. The idea is to create new drugs through a mechanism-based and structure-driven process that reduces overactive Frizzled signaling in tumors such as FZD5 in pancreatic cancer. With the proposed experiments, we will increase the understanding of the regulation of tumor-causing WNT and Frizzled signals in different tumor forms. A better understanding will also open up new points of attack for therapy. In addition, we now have the opportunity to create drugs that directly affect Frizzled receptors. Such substances have been sought after for decades but the methodology to produce them was lacking. This first step in the development of substances that affect Frizzleds will enable a new therapeutic strategy for cancer therapy. The substances will both be important for cancer treatment as well as for advanced preclinical research around Frizzleds.

Some tumors rely on an overactive signaling pathway where WNT proteins activate Frizzled surface receptors in the tumor cells. The WNT / Frizzled signal cascade controls survival and cell division in tumor cells and thus contributes to tumor growth. Among other things, rectal, pancreatic, skin and breast tumors show increased activity of WNT / Frizzled signals. Based on our new research findings on the ability of Frizzled to give rise to various biochemical changes within the cell, we here propose various pharmacological approaches to slow down WNT / Frizzled dependent cell division and thus create new treatment possibilities for cancer. Previously, we have supported specific signaling pathways that are activated by Frizzled receptors on the inside of cells, with the support of the cancer fund. We will use the new research findings to more accurately describe the interaction between different signal cascades in regulation of tumor growth. We will use models for pancreatic, skin and breast cancer in experiments with cell, zebrafish and mouse models. Patient tests serve to confirm our hypothesis in man. In addition, we will use new measurement methods for Frizzled activation that will enable to find molecules that reduce activation of Frizzled and which are therefore candidates for new cancer treatments. With the proposed experiments, we will increase the understanding of the regulation of tumor-causing WNT signals in various tumor forms. A better understanding will also open new approaches for therapy. In addition, we now have the opportunity to create drugs that directly affect Frizzled receptors. Such substances have been coveted for decades but the methodology was lacking to produce them. This first step in the development of substances that affect Frizzleds will begin a new wave of drug development. The substances will both be important for cancer treatment and for the more advanced preclinical research around Frizzleds.

Some tumors rely on an overactive signaling pathway where WNT proteins activate Frizzled surface receptors in the tumor cells. The WNT / Frizzled signal cascade controls survival and cell division in tumor cells and thus contributes to tumor growth. Among other things, rectal, pancreatic, skin and breast tumors show increased activity of WNT / Frizzled signals. Based on our new research findings on the ability of Frizzled to give rise to various biochemical changes within the cell, we here propose various pharmacological approaches to slow down WNT / Frizzled dependent cell division and thus create new treatment possibilities for cancer. Previously, we have supported specific signaling pathways that are activated by Frizzled receptors on the inside of cells, with the support of the cancer fund. We will use the new research findings to more accurately describe the interaction between different signal cascades in regulation of tumor growth. We will use models for pancreatic, skin and breast cancer in experiments with cell, zebrafish and mouse models. Patient tests serve to confirm our hypothesis in man. In addition, we will use new measurement methods for Frizzled activation that will enable to find molecules that reduce activation of Frizzled and which are therefore candidates for new cancer treatments. With the proposed experiments, we will increase the understanding of the regulation of tumor-causing WNT signals in various tumor forms. A better understanding will also open new approaches for therapy. In addition, we now have the opportunity to create drugs that directly affect Frizzled receptors. Such substances have been coveted for decades but the methodology was lacking to produce them. This first step in the development of substances that affect Frizzleds will begin a new wave of drug development. The substances will both be important for cancer treatment and for the more advanced preclinical research around Frizzleds.

Brain tumors such as glioma belong to the most angry cancers with very short survival after diagnosis. In this project, we focus on the communication between tumor cells in the brain and the brain's immune cells using a signaling system called WNT / Frizzled. The signaling system is important in several types of cancer and is found to be of importance also for glioma. Unfortunately, the signal transmission through WNT / Frizzled is so complex that we do not understand how communication works at the molecular level. Because of this, there are currently no drugs that are able to selectively attack WNT / Frizzled communication. During the project, we want to increase our understanding of the WNT / Frizzled signaling in particular between glioma cells and the brain's immune cells. We want to characterize the significance of the WNT / Frizzled signals to the emergence, maintenance and spread of the glioma cells in the brain. The interaction between astrocytes and glioma cells is in focus as we believe it benefits the tumor spread. In addition, the WNT signals appear to be important for a localized reduction of the immune system in the tumor, which in turn favors tumor survival. Thus, we have identified two important goals for a mechanism-based glioma treatment. To be able to, with pharmacological agents, interfere with cellular interaction between the glioma cells and the brain's immune cells for improved treatment, we will use the newly acquired knowledge of WNT / Frizzled signals to find and create drugs that block tumor-supporting WNT / Frizzled signals in glioma. It is hoped that our research will help to develop drugs that work directly at Frizzleds. These tumor-inhibiting substances could be used as a supplement to more conventional therapy to improve patients' situation. Such substances are also attractive for the treatment of other cancers and diseases.

Brain tumors such as glioma belong to the most angry cancers with very short survival after diagnosis. In this project, we focus on the communication between tumor cells in the brain and the brain's immune cells using a signaling system called WNT / Frizzled. The signaling system is important in several types of cancer and is found to be of importance also for glioma. Unfortunately, the signal transmission through WNT / Frizzled is so complex that we do not understand how communication works at the molecular level. Because of this, there are currently no drugs that are able to selectively attack WNT / Frizzled communication. During the project, we want to increase our understanding of the WNT / Frizzled signaling in particular between glioma cells and the brain's immune cells. We want to characterize the significance of the WNT / Frizzled signals to the emergence, maintenance and spread of the glioma cells in the brain. The interaction between astrocytes and glioma cells is in focus as we believe it benefits the tumor spread. In addition, the WNT signals appear to be important for a localized reduction of the immune system in the tumor, which in turn favors tumor survival. Thus, we have identified two important goals for a mechanism-based glioma treatment. To be able to, with pharmacological agents, interfere with cellular interaction between the glioma cells and the brain's immune cells for improved treatment, we will use the newly acquired knowledge of WNT / Frizzled signals to find and create drugs that block tumor-supporting WNT / Frizzled signals in glioma. It is hoped that our research will help to develop drugs that work directly at Frizzleds. These tumor-inhibiting substances could be used as a supplement to more conventional therapy to improve patients' situation. Such substances are also attractive for the treatment of other cancers and diseases.

Brain tumors such as glioma belong to the most angry cancers with very short survival after diagnosis. In this project, we focus on the communication between tumor cells in the brain and the brain's immune cells using a signaling system called WNT / Frizzled. The signaling system is important in several types of cancer and is found to be of importance also for glioma. Unfortunately, the signal transmission through WNT / Frizzled is so complex that we do not understand how communication works at the molecular level. Because of this, there are currently no drugs that are able to selectively attack WNT / Frizzled communication. During the project, we want to increase our understanding of the WNT / Frizzled signaling in particular between glioma cells and the brain's immune cells. We want to characterize the significance of the WNT / Frizzled signals to the emergence, maintenance and spread of the glioma cells in the brain. The interaction between astrocytes and glioma cells is in focus as we believe it benefits the tumor spread. In addition, the WNT signals appear to be important for a localized reduction of the immune system in the tumor, which in turn favors tumor survival. Thus, we have identified two important goals for a mechanism-based glioma treatment. To be able to, with pharmacological agents, interfere with cellular interaction between the glioma cells and the brain's immune cells for improved treatment, we will use the newly acquired knowledge of WNT / Frizzled signals to find and create drugs that block tumor-supporting WNT / Frizzled signals in glioma. It is hoped that our research will help to develop drugs that work directly at Frizzleds. These tumor-inhibiting substances could be used as a supplement to more conventional therapy to improve patients' situation. Such substances are also attractive for the treatment of other cancers and diseases.