Functional characterization of the oncofetal marker Neighbor of Punc E11 (Nope) in a liver-specific knockout mouse model.

• Applicant: Dr. Susanne Zweerink
• Subject Area: Gastroenterology
• Term: since 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 496556962

According to the WHO, HCC is the second most common cancer that causes death. The prognosis and survival rate for the patient depends strongly on the stage of HCC at the time of diagnosis. The identification of biomarkers for early detection of HCC is therefore an important research approach to improve the prognosis. Biomarkers are characterized by the fact that they do not occur in healthy tissue and only occur in case of damage or tissue alteration (e.g. carcinogenesis). Our current findings on the expression of Neighbor of Punc E11 (Nope) underline the potential of this biomarker to improve current HCC diagnostics. Nope is an oncofetal hepatocellular membrane protein. It is physiologically expressed in fetal liver development until about 3 weeks postnatally. It is not detectable in the adult liver, but is expressed directly in acute and progressive liver damage models, especially in damage associated with loss of polarization. In addition, it has been shown to detect murine and human hepatocellular carcinomas (HCC) with high sensitivity and specificity and as a complementary biomarker especially with glypican 3 (GPC-3) it could complement the diagnosis of human HCC. Although the protein is similar in structure to cell adhesion molecules and has a high structural similarity to Punc and the axon guidance receptors Neogenin and deleted in colorectal cancer (DCC), the biological process in which Nope is involved as well as the molecular function of Nope are still unknown. In subproject 1 we will investigate the influence of Nope on the functional microarchitecture of the liver, the polarization of hepatocytes and the differentiation during liver development. Therefore, a liver-specific conditional Nope -/- mouse line will be analyzed phenotypically, macroscopically and microscopically. In subproject 2 the biological process in which Nope is involved will be identified. To this end, the Nope -/- mouse line will be confronted with known damage models in which Nope is normally expressed. In subproject 3 the molecular function of Nope will be analyzed on the intracellular level using activity-based protein profiling (ABPP). After the identification of possible interaction partners, they will finally be tested for their therapeutic efficiency (druggable kinases, potential anti-cancer chemotherapeutics). The overall project provides new insights into the organogenesis of the liver, expands the knowledge on polarization and repolarization of hepatocytes in liver damage and regeneration, and enables a preclinical evaluation of Nope as a biomarker for new therapy-relevant interaction partners in human HCC.

• DFG Programme: Research Grants