0000000000160984
AUTHOR
Stefan Wöll
showing 14 related works from this author
Aberrantly activated claudin 6 and 18.2 as potential therapy targets in non-small-cell lung cancer
2014
Claudins (CLDNs) are central components of tight junctions that regulate epithelial-cell barrier function and polarity. Altered CLDN expression patterns have been demonstrated in numerous cancer types and lineage-specific CLDNs have been proposed as therapy targets. The objective of this study was to assess which fraction of patients with non-small-cell lung cancer (NSCLC) express CLDN6 and CLDN18 isoform 2 (CLDN18.2). Protein expression of CLDN6 and CLDN18.2 was examined by immunohistochemistry on a tissue microarray (n=355) and transcript levels were supportively determined based on gene expression microarray data from fresh-frozen NSCLC tissues (n=196). Both were analyzed with regard to …
Abstract 1778: Preclinical characterization of the safety and antitumor activity of IMAB027-vcMMAE, an anticlaudin 6 antibody-drug conjugate
2018
Abstract Background Claudin 6 (CLDN6) is a tight junction membrane protein whose expression in normal tissue is confined to embryonic cells, but is aberrantly expressed in various human cancers. The anti-CLDN6 monoclonal antibody (mAb), IMAB027, has shown promising antitumor activity in preclinical human CLDN6-positive (CLDN6+) cancer models. Conjugation of IMAB027 with monomethyl auristatin E (MMAE) may utilize the precision tumor-targeting of the mAb to deliver a highly effective cytotoxic drug to the tumor. In this report we present the preclinical characterization of this antibody–drug conjugate, IMAB027–vcMMAE. Methods Internalization of IMAB027 in various CLDN6+ human ovarian (OC) and…
Claudin 18.2 is a target for IMAB362 antibody in pancreatic neoplasms
2013
The majority of pancreatic neoplasms are characterized by a generally lethal progress within a short period of time after primary diagnosis and the mortality of patients is expected to increase further. Due to lack of efficient screening programs and moderate response to treatments, novel compounds for treatment are needed. We investigated the CLDN18.2 expression in affected patients as in vitro feasibility study for a potential treatment with the novel antibody IMAB362. Therefore, we analyzed the expression of CLDN18.2 in normal pancreatic tissues (N = 24), primary lesions (N = 202), metastases (N = 84) and intra-individually matched samples (N = 48) of patients with pancreatic ductal aden…
Characterization of zolbetuximab in pancreatic cancer models
2018
ABSTRACT In healthy tissue, the tight junction protein Claudin 18.2 (CLDN18.2) is present only in the gastric mucosa. Upon malignant transformation of gastric epithelial tissue, perturbations in cell polarity lead to cell surface exposure of CLDN18.2 epitopes. Moreover, CLDN18.2 is aberrantly expressed in malignancies of several other organs, such as pancreatic cancer (PC). A monoclonal antibody, zolbetuximab (formerly known as IMAB362), has been generated against CLDN18.2. In a phase 2 clinical trial (FAST: NCT01630083), zolbetuximab in conjunction with chemotherapy prolonged overall and progression-free survival over chemotherapy alone and improved quality of life. In this study, the mech…
Focal adhesions are hotspots for keratin filament precursor formation
2006
Recent studies showed that keratin filament (KF) formation originates primarily from sites close to the actin-rich cell cortex. To further characterize these sites, we performed multicolor fluorescence imaging of living cells and found drastically increased KF assembly in regions of elevated actin turnover, i.e., in lamellipodia. Abundant KF precursors (KFPs) appeared within these areas at the distal tips of actin stress fibers, moving alongside the stress fibers until their integration into the peripheral KF network. The earliest KFPs were detected next to actin-anchoring focal adhesions (FAs) and were only seen after the establishment of FAs in emerging lamellipodia. Tight spatiotemporal …
Dissection of keratin dynamics: different contributions of the actin and microtubule systems.
2005
It has only recently been recognized that intermediate filaments (IFs) and their assembly intermediates are highly motile cytoskeletal components with cell-type- and isotype-specific characteristics. To elucidate the cell-type-independent contribution of actin filaments and microtubules to these motile properties, fluorescent epithelial IF keratin polypeptides were introduced into non-epithelial, adrenal cortex-derived SW13 cells. Time-lapse fluorescence microscopy of stably transfected SW13 cell lines synthesizing fluorescent human keratin 8 and 18 chimeras HK8-CFP and HK18-YFP revealed extended filament networks that are entirely composed of transgene products and exhibit the same dynamic…
Abstract 1907: Claudin 6 is a carcinoembryonic antigen with cancer stem cell marker features
2018
Abstract Background Claudin 6 (CLDN6) is a tight junction membrane protein whose expression in normal tissue is confined to embryonic cells, but is aberrantly expressed in various human cancers, such as ovarian cancer (OC) and testicular cancer (TC). A monoclonal antibody against CLDN6, IMAB027, has shown promising antitumor activity in preclinical human CLDN6-positive (CLDN6+) cancer models. In this series of nonclinical studies, we investigated CLDN6 expression in normal and cancer tissues, as well as the localization and possible function of CLDN6 in cancer cells. Methods Expression of CLDN6 was assessed in a wide range of human tissues (eg, lung, colon, skin, ovary) and cultured cells b…
Abstract 882: The anti-claudin 6 antibody, IMAB027, induces antibody-dependent cellular and complement-dependent cytotoxicity in claudin 6-expressing…
2018
Abstract Background Claudin 6 (CLDN6) is a tight junction membrane protein whose expression in normal tissue is confined to embryonic cells, but aberrantly expressed in various human cancer types, including some with a high medical need (eg, ovarian and uterine cancers). This tumor-specific expression in adult organs makes CLDN6 an attractive drug target; as such, IMAB027, an anti-CLDN6 monoclonal antibody (mAb), was developed. This report describes the preclinical characteristics of IMAB027. Methods IMAB027 was generated by hybridoma technology; the discovery process was set up so that mAbs that were good binders as well as inducers of the immune effector mechanisms of antibody-dependent c…
Identification of Novel Principles of Keratin Filament Network Turnover in Living Cells
2004
It is generally assumed that turnover of the keratin filament system occurs by exchange of subunits along its entire length throughout the cytoplasm. We now present evidence that a circumscribed submembranous compartment is actually the main site for network replenishment. This conclusion is based on the following observations in living cells synthesizing fluorescent keratin polypeptides: 1) Small keratin granules originate in close proximity to the plasma membrane and move toward the cell center in a continuous motion while elongating into flexible rod-like fragments that fuse with each other and integrate into the peripheral KF network. 2) Recurrence of fluorescence after photobleaching i…
The Process-inducing Activity of Transmembrane Agrin Requires Follistatin-like Domains
2009
Clustering or overexpression of the transmembrane form of the extracellular matrix proteoglycan agrin in neurons results in the formation of numerous highly motile filopodia-like processes extending from axons and dendrites. Here we show that similar processes can be induced by overexpression of transmembrane-agrin in several non-neuronal cell lines. Mapping of the process-inducing activity in neurons and non-neuronal cells demonstrates that the cytoplasmic part of transmembrane agrin is dispensable and that the extracellular region is necessary for process formation. Site-directed mutagenesis reveals an essential role for the loop between beta-sheets 3 and 4 within the Kazal subdomain of t…
Clustering transmembrane-agrin induces filopodia-like processes on axons and dendrites
2005
The transmembrane form of agrin (TM-agrin) is primarily expressed in the CNS, particularly on neurites. To analyze its function, we clustered TM-agrin on neurons using anti-agrin antibodies. On axons from the chick CNS and PNS as well as on axons and dendrites from mouse hippocampal neurons anti-agrin antibodies induced the dose- and time-dependent formation of numerous filopodia-like processes. The processes appeared within minutes after antibody addition and contained a complex cytoskeleton. Formation of processes required calcium, could be inhibited by cytochalasine D, but was not influenced by staurosporine, heparin or pervanadate. Time-lapse video microscopy revealed that the processes…
An RNA vaccine drives expansion and efficacy of claudin-CAR-T cells against solid tumors.
2019
A one-two, CAR-T cell punch Chimeric antigen receptor (CAR)–T cells have been clinically effective in killing certain hematological malignancies, but achieving long-term patient responses for solid tumors remains a challenge. Reinhard et al. describe a two-part “CARVac” strategy to overcome poor CAR-T cell stimulation and responses in vivo. They introduce the tight junction protein claudin 6 (CLDN6) as a new CAR-T cell target and designed a nanoparticulate RNA vaccine encoding a chimeric receptor directed toward CLDN6. This lipoplex RNA vaccine promotes CLDN6 expression on the surface of dendritic cells, which in turn stimulates and enhances the efficacy of CLDN6-CAR-T cells for improved tu…
In vivo imaging and quantification of the continuous keratin filament network turnover
2008
Keratin polypeptides are major components of the epithelial cytoskeleton forming a filamentous 3D-network. Like intermediate filament polypeptides of other cell types, keratins make up a stable, but elastic network that is responsible for mechanical stress resilience. At the same time the keratin network is able to change its shape during development, cell division, metastasis and cell migration.
p38 MAPK-dependent shaping of the keratin cytoskeleton in cultured cells
2007
Plasticity of the resilient keratin intermediate filament cytoskeleton is an important prerequisite for epithelial tissue homeostasis. Here, the contribution of stress-activated p38 MAPK to keratin network organization was examined in cultured cells. It was observed that phosphorylated p38 colocalized with keratin granules that were rapidly formed in response to orthovanadate. The same p38p recruitment was noted during mitosis, in various stress situations and in cells producing mutant keratins. In all these situations keratin 8 became phosphorylated on S73, a well-known p38 target site. To demonstrate that p38-dependent keratin phosphorylation determines keratin organization, p38 activity …