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result(s) for
"Ebert, Matthias P"
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In Vitro Generation of Functional Liver Organoid-Like Structures Using Adult Human Cells
by
Ramachandran, Sarada Devi
,
Heinz, Stefan
,
Ebert, Matthias P.
in
Adult
,
Albumins - genetics
,
Albumins - metabolism
2015
In this study we used differentiated adult human upcyte® cells for the in vitro generation of liver organoids. Upcyte® cells are genetically engineered cell strains derived from primary human cells by lenti-viral transduction of genes or gene combinations inducing transient proliferation capacity (upcyte® process). Proliferating upcyte® cells undergo a finite number of cell divisions, i.e., 20 to 40 population doublings, but upon withdrawal of proliferation stimulating factors, they regain most of the cell specific characteristics of primary cells. When a defined mixture of differentiated human upcyte® cells (hepatocytes, liver sinusoidal endothelial cells (LSECs) and mesenchymal stem cells (MSCs)) was cultured in vitro on a thick layer of Matrigel™, they self-organized to form liver organoid-like structures within 24 hours. When further cultured for 10 days in a bioreactor, these liver organoids show typical functional characteristics of liver parenchyma including activity of cytochromes P450, CYP3A4, CYP2B6 and CYP2C9 as well as mRNA expression of several marker genes and other enzymes. In summary, we hereby describe that 3D functional hepatic structures composed of primary human cell strains can be generated in vitro. They can be cultured for a prolonged period of time and are potentially useful ex vivo models to study liver functions.
Journal Article
MEK inhibitors activate Wnt signalling and induce stem cell plasticity in colorectal cancer
2019
In colorectal cancer (CRC), aberrant Wnt signalling is essential for tumorigenesis and maintenance of cancer stem cells. However, how other oncogenic pathways converge on Wnt signalling to modulate stem cell homeostasis in CRC currently remains poorly understood. Using large-scale compound screens in CRC, we identify MEK1/2 inhibitors as potent activators of Wnt/β-catenin signalling. Targeting MEK increases Wnt activity in different CRC cell lines and murine intestine in vivo. Truncating mutations of APC generated by CRISPR/Cas9 strongly synergize with MEK inhibitors in enhancing Wnt responses in isogenic CRC models. Mechanistically, we demonstrate that MEK inhibition induces a rapid downregulation of AXIN1. Using patient-derived CRC organoids, we show that MEK inhibition leads to increased Wnt activity, elevated
LGR5
levels and enrichment of gene signatures associated with stemness and cancer relapse. Our study demonstrates that clinically used MEK inhibitors inadvertently induce stem cell plasticity, revealing an unknown side effect of RAS pathway inhibition.
Wnt signaling is necessary for colorectal cancer tumorigenesis and stem cell maintenance. Here, the authors identify MEK1/2 inhibitors as potent activators of Wnt/β-catenin signalling and show that clinically approved MEK inhibitors inadvertently induce stem cell plasticity in colorectal cancer
Journal Article
The drug-induced phenotypic landscape of colorectal cancer organoids
2022
Patient-derived organoids resemble the biology of tissues and tumors, enabling ex vivo modeling of human diseases. They have heterogeneous morphologies with unclear biological causes and relationship to treatment response. Here, we use high-throughput, image-based profiling to quantify phenotypes of over 5 million individual colorectal cancer organoids after treatment with >500 small molecules. Integration of data using multi-omics modeling identifies axes of morphological variation across organoids: Organoid size is linked to IGF1 receptor signaling, and cystic vs. solid organoid architecture is associated with LGR5 + stemness. Treatment-induced organoid morphology reflects organoid viability, drug mechanism of action, and is biologically interpretable. Inhibition of MEK leads to cystic reorganization of organoids and increases expression of
LGR5
, while inhibition of mTOR induces IGF1 receptor signaling. In conclusion, we identify shared axes of variation for colorectal cancer organoid morphology, their underlying biological mechanisms, and pharmacological interventions with the ability to move organoids along them.
The heterogeneity underlying cancer organoid phenotypes is not yet well understood. Here, the authors develop an imaging analysis assay for high throughput phenotypic screening of colorectal organoids that allows to define specific morphological changes that occur following different drug treatments.
Journal Article
Precision medicine for metastatic colorectal cancer in clinical practice
by
Betge, Johannes
,
Ebert, Matthias P.
,
Riedesser, Julian E.
in
Cancer
,
Chemotherapy
,
Colorectal cancer
2022
Globally, metastatic colorectal cancer is one of the leading causes for cancer-related death. Treatment limited to conventional chemotherapeutics extended life for only a few months. However, advances in surgical approaches and medical treatment regimens have greatly increased survival, even leading to long-term remission in selected patients. Advances in multiomics analysis of tumors have built a foundation for molecular-targeted therapies. Furthermore, immunotherapies are on the edge of revolutionizing oncological practice. This review summarizes recent advances in the growing toolbox of personalized treatment for patients with metastatic colorectal cancer. We provide an overview of current multimodal therapy and explain novel immunotherapy and targeted therapy approaches in detail. We emphasize clinically relevant therapies, such as inhibitors of MAPK signaling, and give recommendations for clinical practice. Finally, we describe the potential predictive impact of molecular subtypes and provide an outlook on novel concepts, such as functional precision medicine.
Journal Article
Association of patterns of class I histone deacetylase expression with patient prognosis in gastric cancer: a retrospective analysis
by
Ebert, Matthias PA
,
Pross, Matthias
,
Denkert, Carsten
in
Aged
,
Biomarkers, Tumor - analysis
,
Biomarkers, Tumor - biosynthesis
2008
Although histone deacetylases (HDACs) are known to have an important regulatory role in cancer cells, and HDAC inhibitors (HDIs) have entered late-phase clinical trials for the treatment of several cancers, little is known about the expression patterns of HDAC isoforms in tumours. We aimed to clarify these expression patterns and identify potential diagnostic and prognostic uses of selected class I HDAC isoforms in gastric cancer.
Tissue samples from a training cohort and a validation cohort of patients with gastric cancer from two German institutions were used for analyses. Tissue microarrays were generated from tumour tissue collected from patients in the training group, whereas tissue slides were used in the validation group. The tissues were scored for expression of class I HDAC isoforms 1, 2, and 3. Overall expression patterns (gHDAC) were grouped as being negative (all three isoforms negative), partially positive (one or two isoforms positive), or completely positive (all isoforms positive), and correlated with clinicopathological parameters and patient survival. The main endpoints were amount of expression of each of the three HDAC isoforms, patterns of expression of gHDAC, effect of metastasis on expression of HDAC and gHDAC, and overall survival according to HDAC expression patterns.
2617 tissue microarray spots from 143 patients in the training cohort and 606 tissue slides from 150 patients in the validation cohort were studied. 52 of the 143 (36%) gastric tumours in the training cohort and 32 of the 150 (21%) gastric tumours in the validation cohort showed nuclear expression of all three HDAC isoforms. 60 (42%) of tumours in the training cohort and 65 (43%) in the validation cohort expressed one or two isoforms in the nuclei, whereas 31 (22%) of tumours in the training cohort and 53 (35%) in the validation cohort were scored negative for all three proteins. gHDAC expression in both cohorts was higher when lymph-node metastases were present (p=0·0175 for the training group and p=0·0242 for the validation group). Survival data were available for 49 patients in the training group and 123 patients in the validation group. In the validation cohort, 3-year survival was 44% (95% CI 34–57) in the HDAC1-negative group, 50% (39–64) in the HDAC2-negative group, and 48% (34–67) in the gHDAC-negative group. 3-year survival decreased to 21% (11–37) when HDAC1 was positive, 16% (9–31) when HDAC2 was positive, and 5% (1–31) when gHDAC (all isoforms) were positive. Those patients highly expressing one or two isoforms (the gHDAC-intermediate group) had an estimated 3-year survival of 40% (29–56). In multivariate analyses, high gHDAC and HDAC2 expression were associated with shorter survival in the training cohort (gHDAC: hazard ratio [HR] 4·15 [1·23–13·99], p=0·0250; HDAC2: HR 3·58 [1·36–9·44], p=0·0100) and in the validation cohort (gHDAC: HR 2·18 [1·19–4·01], p=0·0433; HDAC2: HR 1·72 [1·08–2·73], p=0·0225), independent of standard clinical predictors.
High HDAC expression is significantly associated with nodal spread and is an independent prognostic marker for gastric cancer. Additionally, we postulate that immunohistochemical detection of HDAC as a companion diagnostic method might predict treatment response to HDIs, thereby enabling selection of patients for this specific targeted treatment in gastric cancer.
Journal Article
TFAP2E–DKK4 and Chemoresistance in Colorectal Cancer
by
Porschen, Rainer
,
Stöhlmacher-Williams, Jan
,
Kretzschmar, Antje Karen
in
5-Fluorouracil
,
Aged
,
Antineoplastic Agents - therapeutic use
2012
Patients whose tumors showed methylation and decreased expression of the gene
TFAP2E
were more than five times as likely as patients with normal
TFAP2E
gene expression to have resistance to fluorouracil.
The treatment options and prognosis for patients with advanced colorectal cancer have improved through the development of novel drugs.
1
,
2
However, studies of the molecular biology of cancer initiation and progression have so far provided scant knowledge of the molecular mechanisms contributing to chemotherapy resistance.
2
Epigenetic alterations underlying the pathogenesis of colorectal cancer have been reported by several groups.
3
These alterations include hypomethylation and hypermethylation of DNA as well as histone modifications, all of which have a profound effect on transcriptional gene regulation. The role of these molecular alterations in response prediction and treatment resistance are far less well known. . . .
Journal Article
Liver cancer cell lines distinctly mimic the metabolic gene expression pattern of the corresponding human tumours
by
Rothley, Melanie
,
Piorońska, Weronika
,
Ebert, Matthias P.
in
Apoptosis
,
Biomarkers
,
Biomedical and Life Sciences
2018
Background
Although metabolism is profoundly altered in human liver cancer, the extent to which experimental models, e.g. cell lines, mimic those alterations is unresolved. Here, we aimed to determine the resemblance of hepatocellular carcinoma (HCC) cell lines to human liver tumours, specifically in the expression of deregulated metabolic targets in clinical tissue samples.
Methods
We compared the overall gene expression profile of poorly-differentiated (HLE, HLF, SNU-449) to well-differentiated (HUH7, HEPG2, HEP3B) HCC cell lines in three publicly available microarray datasets. Three thousand and eighty-five differentially expressed genes in ≥2 datasets (
P
< 0.05) were used for pathway enrichment and gene ontology (GO) analyses. Further, we compared the topmost gene expression, pathways, and GO from poorly differentiated cell lines to the pattern from four human HCC datasets (623 tumour tissues). In well- versus poorly differentiated cell lines, and in representative models HLE and HUH7 cells, we specifically assessed the expression pattern of 634 consistently deregulated metabolic genes in human HCC. These data were complemented by quantitative PCR, proteomics, metabolomics and assessment of response to thirteen metabolism-targeting compounds in HLE versus HUH7 cells.
Results
We found that poorly-differentiated HCC cells display upregulated MAPK/RAS/NFkB signaling, focal adhesion, and downregulated complement/coagulation cascade, PPAR-signaling, among pathway alterations seen in clinical tumour datasets. In HLE cells, 148 downregulated metabolic genes in liver tumours also showed low gene/protein expression – notably in fatty acid β-oxidation (e.g. ACAA1/2, ACADSB, HADH), urea cycle (e.g. CPS1, ARG1, ASL), molecule transport (e.g.
SLC2A2, SLC7A1, SLC25A15/20
), and amino acid metabolism (e.g. PHGDH, PSAT1, GOT1, GLUD1). In contrast, HUH7 cells showed a higher expression of 98 metabolic targets upregulated in tumours (e.g. HK2, PKM, PSPH, GLUL, ASNS, and fatty acid synthesis enzymes ACLY, FASN). Metabolomics revealed that the genomic portrait of HLE cells co-exist with profound reliance on glutamine to fuel tricarboxylic acid cycle, whereas HUH7 cells use both glucose and glutamine. Targeting glutamine pathway selectively suppressed the proliferation of HLE cells.
Conclusions
We report a yet unappreciated distinct expression pattern of clinically-relevant metabolic genes in HCC cell lines, which could enable the identification and therapeutic targeting of metabolic vulnerabilities at various liver cancer stages.
Journal Article
Performance of Epigenetic Markers SEPT9 and ALX4 in Plasma for Detection of Colorectal Precancerous Lesions
2010
Screening for colorectal cancer (CRC) has shown to reduce cancer-related mortality, however, acceptance and compliance to current programmes are poor. Developing new, more acceptable non-invasive tests for the detection of cancerous and precancerous colorectal lesions would not only allow preselection of individuals for colonoscopy, but may also prevent cancer by removal of precancerous lesions.
Plasma from 128 individuals (cohort I - exploratory study: 73 cases / 55 controls) was used to test the performance of a single marker, SEPT9, using a real-time quantitative PCR assay. To validate performance of SEPT9, plasma of 76 individuals (cohort II - validation study: 54 cases / 22 controls) was assessed. Additionally, improvement of predictive capability considering SEPT9 and additionally ALX4 methylation was investigated within these patients.
In both cohorts combined, methylation of SEPT9 was observed in 9% of controls (3/33), 29% of patients with colorectal precancerous lesions (27/94) and 73% of colorectal cancer patients (24/33). The presence of both SEPT9 and ALX4 markers was analysed in cohort II and was observed in 5% of controls (1/22) and 37% of patients with polyps (18/49). Interestingly, also 3/5 (60%) patients with colorectal cancer were tested positive by the two marker panel in plasma.
While these data confirm the detection rate of SEPT9 as a biomarker for colorectal cancer, they also show that methylated DNA from advanced precancerous colorectal lesions can be detected using a panel of two DNA methylation markers, ALX4 and SEPT9. If confirmed in larger studies these data indicate that screening for colorectal precancerous lesions with a blood-based test may be as feasible as screening for invasive cancer.
Journal Article
MUC1, MUC2, MUC5AC, and MUC6 in colorectal cancer: expression profiles and clinical significance
2016
Mucin glycoprotein expression can be altered during the carcinogenic process. The impact on the prognosis of patients with colorectal cancer (CRC) is controversial. We analyzed tumors from 381 patients for MUC1, MUC2, MUC5AC, and MUC6 expression by immunohistochemical staining, using tissue microarrays. Progression-free and cancer-specific survival were determined using the Kaplan-Meier method. Expression of intestinal mucin MUC2 was lost in 85 (23 %) CRCs, and patients with MUC6-negative tumors showed shorter progression-free survival (PFS,
p
= 0.043). Gastric mucins MUC5AC and MUC6 showed high (>50 %) aberrant expression in 28 (8 %) and 9 (2 %) cases, respectively. High expression of MUC5AC was associated with longer PFS (
p
= 0.055). High expression of MUC6 was associated with 100 % PFS (
p
= 0.024) and longer cancer-specific survival (CSS,
p
= 0.043). MUC1 was expressed in 238 (64 %) tumors and had no impact on outcome. When analysis was restricted to stages II and III, loss of MUC2 was associated with adverse outcome. Overexpression of both MUC5AC and MUC6 significantly predicted favorable PFS and CSS. In conclusion, loss of MUC2 expression proved to be a predictor of adverse outcome, while the gain of aberrant expression of MUC5AC and particularly of MUC6 was associated with favorable outcome in CRC, notably in intermediate stages II and III.
Journal Article
Privacy-preserving large language models for structured medical information retrieval
by
Juglan, Radhika
,
Wiest, Isabella Catharina
,
Zhu, Jiefu
in
692/1807/1808
,
692/699/1503/1607
,
692/700
2024
Most clinical information is encoded as free text, not accessible for quantitative analysis. This study presents an open-source pipeline using the local large language model (LLM) “Llama 2” to extract quantitative information from clinical text and evaluates its performance in identifying features of decompensated liver cirrhosis. The LLM identified five key clinical features in a zero- and one-shot manner from 500 patient medical histories in the MIMIC IV dataset. We compared LLMs of three sizes and various prompt engineering approaches, with predictions compared against ground truth from three blinded medical experts. Our pipeline achieved high accuracy, detecting liver cirrhosis with 100% sensitivity and 96% specificity. High sensitivities and specificities were also yielded for detecting ascites (95%, 95%), confusion (76%, 94%), abdominal pain (84%, 97%), and shortness of breath (87%, 97%) using the 70 billion parameter model, which outperformed smaller versions. Our study successfully demonstrates the capability of locally deployed LLMs to extract clinical information from free text with low hardware requirements.
Journal Article