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Papers by Michael Linnebacher

Research paper thumbnail of Immunization of an individual against carcinoma and the preliminary stages thereof

Research paper thumbnail of Immunization of an Individual Against Carcinomas and the Preliminary Stages Thereof

Research paper thumbnail of Tumor antigen and MHC expression in glioma cells for immunotherapeutic interventions

World Journal of Immunology, 2013

Research paper thumbnail of A Comprehensive Approach to Patient-individual Glioblastoma Multiforme Model Establishment

Patient-individual tumor models for Glioblastoma Multiforme (GBM) are important not only for basi... more Patient-individual tumor models for Glioblastoma Multiforme (GBM) are important not only for basic and translational research but also for the development and improvement of optimal and individualized treatment strategies. The model that has gained widest acceptance is the primary cell culture model. The laborious and time consuming process is rewarded with a relative high initial success rate (about 60%). We here describe and evaluate an extended biobanking methodology to simplify sample collection and model establishment. GBM resection specimen were collected ad hoc, partially prepared fresh for modeling, snap frozen for molecular testing and frozen down vitally. The established models were subject to subsequent detailed characterization in direct comparison to the patients´ tumors. Generally, molecular characteristics such as mutations, gene amplifications and epigenetic alterations were maintained in the models. Immortality, neuronal origin and stem cell characteristics of the c...

Research paper thumbnail of The molecular landscape of colorectal cancer cell lines unveils clinically actionable kinase targets

Nature Communications, 2015

Research paper thumbnail of Cannabinoids increase lung cancer cell lysis by lymphokine-activated killer cells via upregulation of ICAM-1

Biochemical Pharmacology, 2014

Cannabinoids have been shown to promote the expression of the intercellular adhesion molecule 1 (... more Cannabinoids have been shown to promote the expression of the intercellular adhesion molecule 1 (ICAM-1) on lung cancer cells as part of their anti-invasive and antimetastatic action. Using lung cancer cell lines (A549, H460) and metastatic cells derived from a lung cancer patient, the present study addressed the impact of cannabinoid-induced ICAM-1 on cancer cell adhesion to lymphokine-activated killer (LAK) cells and LAK cell-mediated cytotoxicity. Cannabidiol (CBD), a non-psychoactive cannabinoid, enhanced the susceptibility of cancer cells to adhere to and subsequently be lysed by LAK cells, with both effects being reversed by a neutralizing ICAM-1 antibody. Increased cancer cell lysis by CBD was likewise abrogated when CBD-induced ICAM-1 expression was blocked by specific siRNA or by antagonists to cannabinoid receptors (CB1, CB2) and to transient receptor potential vanilloid 1. In addition, enhanced killing of CBD-treated cancer cells was reversed by preincubation of LAK cells with an antibody to lymphocyte function associated antigen-1 (LFA-1) suggesting intercellular ICAM-1/LFA-1 crosslink as crucial event within this process. ICAM-1-dependent pro-killing effects were further confirmed for the phytocannabinoid Δ(9)-tetrahydrocannabinol (THC) and R(+)-methanandamide (MA), a hydrolysis-stable endocannabinoid analogue. Finally, each cannabinoid elicited no significant increase of LAK cell-mediated lysis of non-tumor bronchial epithelial cells, BEAS-2B, associated with a far less pronounced (CBD, THC) or absent (MA) ICAM-1 induction as compared to cancer cells. Altogether, our data demonstrate cannabinoid-induced upregulation of ICAM-1 on lung cancer cells to be responsible for increased cancer cell lysis by LAK cells. These findings provide proof for a novel antitumorigenic mechanism of cannabinoids.

Research paper thumbnail of Establishment and Characterization of Primary Glioblastoma Cell Lines from Fresh and Frozen Material: A Detailed Comparison

Research paper thumbnail of MicroRNA-mRNA interactions in colorectal cancer and their role in tumor progression

Genes, Chromosomes and Cancer, 2015

Research paper thumbnail of Tumor-infiltrating B cells: The ignored players in tumor immunology

Research paper thumbnail of COX-2 and PPAR-  Confer Cannabidiol-Induced Apoptosis of Human Lung Cancer Cells

Molecular Cancer Therapeutics, 2013

Research paper thumbnail of Identification of HLA-A*0201-restricted CTL epitopes encoded by the tumor-specificMAGE-2 gene product

International Journal of Cancer, 1997

Research paper thumbnail of Mistletoe lectin has a shiga toxin-like structure and should be combined with other Toll-like receptor ligands in cancer therapy

Cancer Immunology, Immunotherapy, 2013

Research paper thumbnail of Characterization of FAMPAC, a newly identified human pancreatic carcinoma cell line with a hereditary background

Research paper thumbnail of Expression of young HERV-H loci in the course of colorectal carcinoma and correlation with molecular subtypes

Oncotarget, Jan 24, 2015

Expression of the human endogenous retrovirus (HERV)-H family has been associated with colorectal... more Expression of the human endogenous retrovirus (HERV)-H family has been associated with colorectal carcinomas (CRC), yet no individual HERV-H locus expression has been thoroughly correlated with clinical data.Here, we characterized HERV-H reactivations in clinical CRC samples by integrating expression profiles, molecular patterns and clinical data. Expression of relevant HERV-H sequences was analyzed by qRT-PCR on two well-defined clinical cohorts (n = 139 pairs of tumor and adjacent normal colon tissue) including samples from adenomas (n = 21) and liver metastases (n = 16). Correlations with clinical and molecular data were assessed. CRC specific HERV-H sequences were validated and found expressed throughout CRC disease progression. Correlations between HERV-H expression and lymph node invasion of tumor cells (p = 0.0006) as well as microsatellite instable tumors (p < 0.0001) were established. No association with regard to age, tumor localization, grading or common mutations beca...

Research paper thumbnail of Functional Characterization and Drug Response of Freshly Established Patient-Derived Tumor Models with CpG Island Methylator Phenotype

PloS one, 2015

Patient-individual tumor models constitute a powerful platform for basic and translational analys... more Patient-individual tumor models constitute a powerful platform for basic and translational analyses both in vitro and in vivo. However, due to the labor-intensive and highly time-consuming process, only few well-characterized patient-derived cell lines and/or corresponding xenografts exist. In this study, we describe successful generation and functional analysis of novel tumor models from patients with sporadic primary colorectal carcinomas (CRC) showing CpG island methylator phenotype (CIMP). Initial DNA fingerprint analysis confirmed identity with the patient in all four cases. These freshly established cells showed characteristic features associated with the CIMP-phenotype (HROC40: APCwt, TP53mut, KRASmut; 3/8 marker methylated; HROC43: APCmut, TP53mut, KRASmut; 4/8 marker methylated; HROC60: APCwt, TP53mut, KRASwt; 4/8 marker methylated; HROC183: APCmut, TP53mut, KRASmut; 6/8 marker methylated). Cell lines were of epithelial origin (EpCAM+) with distinct morphology and growth ki...

Research paper thumbnail of Bacteriolytic therapy of experimental pancreatic carcinoma

World Journal of Gastroenterology Wjg, 2010

Research paper thumbnail of Genes and their genetic products pertinent to microsatellite instable (msi+) tumours

Research paper thumbnail of Celecoxib increases lung cancer cell lysis by lymphokine-activated killer cells via upregulation of ICAM-1

Oncotarget, Jan 22, 2015

The antitumorigenic mechanism of the selective cyclooxygenase-2 (COX-2) inhibitor celecoxib is st... more The antitumorigenic mechanism of the selective cyclooxygenase-2 (COX-2) inhibitor celecoxib is still a matter of debate. Using lung cancer cell lines (A549, H460) and metastatic cells derived from a lung cancer patient, the present study investigates the impact of celecoxib on the expression of intercellular adhesion molecule 1 (ICAM-1) and cancer cell lysis by lymphokine-activated killer (LAK) cells. Celecoxib, but not other structurally related selective COX-2 inhibitors (i.e., etoricoxib, rofecoxib, valdecoxib), was found to cause a substantial upregulation of ICAM-1 protein levels. Likewise, ICAM-1 mRNA expression was increased by celecoxib. Celecoxib enhanced the susceptibility of cancer cells to be lysed by LAK cells with the respective effect being reversed by a neutralizing ICAM-1 antibody. In addition, enhanced killing of celecoxib-treated cancer cells was reversed by preincubation of LAK cells with an antibody to lymphocyte function associated antigen 1 (LFA-1), suggesting...

Research paper thumbnail of Reactivity against microsatellite instability-induced frameshift mutations in patients with inflammatory bowel disease

World journal of gastroenterology : WJG, Jan 7, 2015

To analyze the cellular immune response towards microsatellite-instability (MSI)-induced frameshi... more To analyze the cellular immune response towards microsatellite-instability (MSI)-induced frameshift-peptides (FSPs) in patients suffering from inflammatory bowel disease (IBD) with and without thiopurine-based immunosuppressive treatment. Frequencies of peripheral blood T cell responses of IBD patients (n = 75) against FSPs derived from 14 microsatellite-containing candidate genes were quantified by interferon-γ enzyme-linked immunospot. T cells derived from 20 healthy individuals served as controls. Significant T cell reactivities against MSI-induced FSPs were observed in 59 of 75 IBD patients (78.7%). This was significantly more as we could observe in 20 healthy controls (P = 0.001). Overall, the reactivity was significantly influenced by thiopurine treatment (P = 0.032) and duration of disease (P = 0.002) but not by duration or cumulative amount of thiopurine therapy (P = 0.476). Unexpected, 15 of 24 (62.5%) IBD patients without prior thiopurine treatment also showed increased FS...

Research paper thumbnail of Establishment and characterization of cell lines from chromosomal instable colorectal cancer

World journal of gastroenterology : WJG, Jan 7, 2015

To generate novel tumor models for preclinical validation of biomarkers that allow drug response ... more To generate novel tumor models for preclinical validation of biomarkers that allow drug response prediction and individual therapeutic decisions. Cell line establishment was conducted by both direct in vitro culturing and in vivo xenografting followed by in vitro culturing procedure. A comprehensive characterization was subsequently performed. This included quality control, consisting of the confirmation of human and colorectal cancer (CRC) origin by DNA fingerprint and epithelial cell adhesion molecule (EpCAM) staining, as well as mycoplasma and human virus testing. Phenotypic analysis was done by light microscopy and multicolor flow cytometry. Histopathological examination (β-catenin and cytokeratin staining) was conducted in direct comparison to parental tumor tissues. Extensive molecular-pathological profiling included mutation analysis for CRC-associated driver mutations, assessment of chromosomal and microsatellite instability, and the grade of CpG island methylation. Addition...

Research paper thumbnail of Immunization of an individual against carcinoma and the preliminary stages thereof

Research paper thumbnail of Immunization of an Individual Against Carcinomas and the Preliminary Stages Thereof

Research paper thumbnail of Tumor antigen and MHC expression in glioma cells for immunotherapeutic interventions

World Journal of Immunology, 2013

Research paper thumbnail of A Comprehensive Approach to Patient-individual Glioblastoma Multiforme Model Establishment

Patient-individual tumor models for Glioblastoma Multiforme (GBM) are important not only for basi... more Patient-individual tumor models for Glioblastoma Multiforme (GBM) are important not only for basic and translational research but also for the development and improvement of optimal and individualized treatment strategies. The model that has gained widest acceptance is the primary cell culture model. The laborious and time consuming process is rewarded with a relative high initial success rate (about 60%). We here describe and evaluate an extended biobanking methodology to simplify sample collection and model establishment. GBM resection specimen were collected ad hoc, partially prepared fresh for modeling, snap frozen for molecular testing and frozen down vitally. The established models were subject to subsequent detailed characterization in direct comparison to the patients´ tumors. Generally, molecular characteristics such as mutations, gene amplifications and epigenetic alterations were maintained in the models. Immortality, neuronal origin and stem cell characteristics of the c...

Research paper thumbnail of The molecular landscape of colorectal cancer cell lines unveils clinically actionable kinase targets

Nature Communications, 2015

Research paper thumbnail of Cannabinoids increase lung cancer cell lysis by lymphokine-activated killer cells via upregulation of ICAM-1

Biochemical Pharmacology, 2014

Cannabinoids have been shown to promote the expression of the intercellular adhesion molecule 1 (... more Cannabinoids have been shown to promote the expression of the intercellular adhesion molecule 1 (ICAM-1) on lung cancer cells as part of their anti-invasive and antimetastatic action. Using lung cancer cell lines (A549, H460) and metastatic cells derived from a lung cancer patient, the present study addressed the impact of cannabinoid-induced ICAM-1 on cancer cell adhesion to lymphokine-activated killer (LAK) cells and LAK cell-mediated cytotoxicity. Cannabidiol (CBD), a non-psychoactive cannabinoid, enhanced the susceptibility of cancer cells to adhere to and subsequently be lysed by LAK cells, with both effects being reversed by a neutralizing ICAM-1 antibody. Increased cancer cell lysis by CBD was likewise abrogated when CBD-induced ICAM-1 expression was blocked by specific siRNA or by antagonists to cannabinoid receptors (CB1, CB2) and to transient receptor potential vanilloid 1. In addition, enhanced killing of CBD-treated cancer cells was reversed by preincubation of LAK cells with an antibody to lymphocyte function associated antigen-1 (LFA-1) suggesting intercellular ICAM-1/LFA-1 crosslink as crucial event within this process. ICAM-1-dependent pro-killing effects were further confirmed for the phytocannabinoid Δ(9)-tetrahydrocannabinol (THC) and R(+)-methanandamide (MA), a hydrolysis-stable endocannabinoid analogue. Finally, each cannabinoid elicited no significant increase of LAK cell-mediated lysis of non-tumor bronchial epithelial cells, BEAS-2B, associated with a far less pronounced (CBD, THC) or absent (MA) ICAM-1 induction as compared to cancer cells. Altogether, our data demonstrate cannabinoid-induced upregulation of ICAM-1 on lung cancer cells to be responsible for increased cancer cell lysis by LAK cells. These findings provide proof for a novel antitumorigenic mechanism of cannabinoids.

Research paper thumbnail of Establishment and Characterization of Primary Glioblastoma Cell Lines from Fresh and Frozen Material: A Detailed Comparison

Research paper thumbnail of MicroRNA-mRNA interactions in colorectal cancer and their role in tumor progression

Genes, Chromosomes and Cancer, 2015

Research paper thumbnail of Tumor-infiltrating B cells: The ignored players in tumor immunology

Research paper thumbnail of COX-2 and PPAR-  Confer Cannabidiol-Induced Apoptosis of Human Lung Cancer Cells

Molecular Cancer Therapeutics, 2013

Research paper thumbnail of Identification of HLA-A*0201-restricted CTL epitopes encoded by the tumor-specificMAGE-2 gene product

International Journal of Cancer, 1997

Research paper thumbnail of Mistletoe lectin has a shiga toxin-like structure and should be combined with other Toll-like receptor ligands in cancer therapy

Cancer Immunology, Immunotherapy, 2013

Research paper thumbnail of Characterization of FAMPAC, a newly identified human pancreatic carcinoma cell line with a hereditary background

Research paper thumbnail of Expression of young HERV-H loci in the course of colorectal carcinoma and correlation with molecular subtypes

Oncotarget, Jan 24, 2015

Expression of the human endogenous retrovirus (HERV)-H family has been associated with colorectal... more Expression of the human endogenous retrovirus (HERV)-H family has been associated with colorectal carcinomas (CRC), yet no individual HERV-H locus expression has been thoroughly correlated with clinical data.Here, we characterized HERV-H reactivations in clinical CRC samples by integrating expression profiles, molecular patterns and clinical data. Expression of relevant HERV-H sequences was analyzed by qRT-PCR on two well-defined clinical cohorts (n = 139 pairs of tumor and adjacent normal colon tissue) including samples from adenomas (n = 21) and liver metastases (n = 16). Correlations with clinical and molecular data were assessed. CRC specific HERV-H sequences were validated and found expressed throughout CRC disease progression. Correlations between HERV-H expression and lymph node invasion of tumor cells (p = 0.0006) as well as microsatellite instable tumors (p < 0.0001) were established. No association with regard to age, tumor localization, grading or common mutations beca...

Research paper thumbnail of Functional Characterization and Drug Response of Freshly Established Patient-Derived Tumor Models with CpG Island Methylator Phenotype

PloS one, 2015

Patient-individual tumor models constitute a powerful platform for basic and translational analys... more Patient-individual tumor models constitute a powerful platform for basic and translational analyses both in vitro and in vivo. However, due to the labor-intensive and highly time-consuming process, only few well-characterized patient-derived cell lines and/or corresponding xenografts exist. In this study, we describe successful generation and functional analysis of novel tumor models from patients with sporadic primary colorectal carcinomas (CRC) showing CpG island methylator phenotype (CIMP). Initial DNA fingerprint analysis confirmed identity with the patient in all four cases. These freshly established cells showed characteristic features associated with the CIMP-phenotype (HROC40: APCwt, TP53mut, KRASmut; 3/8 marker methylated; HROC43: APCmut, TP53mut, KRASmut; 4/8 marker methylated; HROC60: APCwt, TP53mut, KRASwt; 4/8 marker methylated; HROC183: APCmut, TP53mut, KRASmut; 6/8 marker methylated). Cell lines were of epithelial origin (EpCAM+) with distinct morphology and growth ki...

Research paper thumbnail of Bacteriolytic therapy of experimental pancreatic carcinoma

World Journal of Gastroenterology Wjg, 2010

Research paper thumbnail of Genes and their genetic products pertinent to microsatellite instable (msi+) tumours

Research paper thumbnail of Celecoxib increases lung cancer cell lysis by lymphokine-activated killer cells via upregulation of ICAM-1

Oncotarget, Jan 22, 2015

The antitumorigenic mechanism of the selective cyclooxygenase-2 (COX-2) inhibitor celecoxib is st... more The antitumorigenic mechanism of the selective cyclooxygenase-2 (COX-2) inhibitor celecoxib is still a matter of debate. Using lung cancer cell lines (A549, H460) and metastatic cells derived from a lung cancer patient, the present study investigates the impact of celecoxib on the expression of intercellular adhesion molecule 1 (ICAM-1) and cancer cell lysis by lymphokine-activated killer (LAK) cells. Celecoxib, but not other structurally related selective COX-2 inhibitors (i.e., etoricoxib, rofecoxib, valdecoxib), was found to cause a substantial upregulation of ICAM-1 protein levels. Likewise, ICAM-1 mRNA expression was increased by celecoxib. Celecoxib enhanced the susceptibility of cancer cells to be lysed by LAK cells with the respective effect being reversed by a neutralizing ICAM-1 antibody. In addition, enhanced killing of celecoxib-treated cancer cells was reversed by preincubation of LAK cells with an antibody to lymphocyte function associated antigen 1 (LFA-1), suggesting...

Research paper thumbnail of Reactivity against microsatellite instability-induced frameshift mutations in patients with inflammatory bowel disease

World journal of gastroenterology : WJG, Jan 7, 2015

To analyze the cellular immune response towards microsatellite-instability (MSI)-induced frameshi... more To analyze the cellular immune response towards microsatellite-instability (MSI)-induced frameshift-peptides (FSPs) in patients suffering from inflammatory bowel disease (IBD) with and without thiopurine-based immunosuppressive treatment. Frequencies of peripheral blood T cell responses of IBD patients (n = 75) against FSPs derived from 14 microsatellite-containing candidate genes were quantified by interferon-γ enzyme-linked immunospot. T cells derived from 20 healthy individuals served as controls. Significant T cell reactivities against MSI-induced FSPs were observed in 59 of 75 IBD patients (78.7%). This was significantly more as we could observe in 20 healthy controls (P = 0.001). Overall, the reactivity was significantly influenced by thiopurine treatment (P = 0.032) and duration of disease (P = 0.002) but not by duration or cumulative amount of thiopurine therapy (P = 0.476). Unexpected, 15 of 24 (62.5%) IBD patients without prior thiopurine treatment also showed increased FS...

Research paper thumbnail of Establishment and characterization of cell lines from chromosomal instable colorectal cancer

World journal of gastroenterology : WJG, Jan 7, 2015

To generate novel tumor models for preclinical validation of biomarkers that allow drug response ... more To generate novel tumor models for preclinical validation of biomarkers that allow drug response prediction and individual therapeutic decisions. Cell line establishment was conducted by both direct in vitro culturing and in vivo xenografting followed by in vitro culturing procedure. A comprehensive characterization was subsequently performed. This included quality control, consisting of the confirmation of human and colorectal cancer (CRC) origin by DNA fingerprint and epithelial cell adhesion molecule (EpCAM) staining, as well as mycoplasma and human virus testing. Phenotypic analysis was done by light microscopy and multicolor flow cytometry. Histopathological examination (β-catenin and cytokeratin staining) was conducted in direct comparison to parental tumor tissues. Extensive molecular-pathological profiling included mutation analysis for CRC-associated driver mutations, assessment of chromosomal and microsatellite instability, and the grade of CpG island methylation. Addition...