Universität zu Köln

Fan, Ningbo ORCID: 0000-0002-1622-6747 (2024). GDF15 as a Potential Target for Overcoming Cancer-Associated Fibroblast Mediated Treatment Resistance in Esophageal Adenocarcinoma. PhD thesis, Universität zu Köln.

PDF (Doctoral dissertation_Ningbo Fan) Doctoral_thesis_Ningbo_Fan_10012024.pdf Download (11MB)

Abstract

Background: Esophageal cancer (EC) ranks as the 7th most common cancer and 6th leading cause of cancer-related deaths worldwide. The standard treatment for locally advanced EC involves neoadjuvant chemoradiotherapy (NCRT)/neoadjuvant chemotherapy (NT) followed by surgery. Cancer-associated fibroblasts (CAFs) play a pivotal role and contribute to various aspects of tumor initiation and progression within the tumor microenvironment (TME). We aim to compare the effectiveness of NCRT and NCT in treating EC patients and to explore the molecular mechanisms underlying treatment resistance in esophageal adenocarcinoma (EAC), with a specific focus on the involvement of CAFs. Methods: A network meta-analysis was performed to compare the effectiveness of NCRT, NCT, and surgery alone in randomized control trials (RCTs) published up to September 2021. EAC CAFs and EAC patient-derived organoids (PDOs) were established from primary patient tissues. Transcriptomic analysis was used to identify potential factors that were involved in CAF-tumor interaction. Lentiviral transduction was conducted to establish stable GDF15 knockdown EAC cells and CAFs. In vitro cell viability assays and apoptosis analysis were performed to assess the sensitivity of EAC cells to chemotherapy and radiotherapy. GDF15 concentration was determined using ELISA. To validate CAF-mediated EAC tumor progression, we utilized EAC PDOs and paired CAFs as an ex vivo preclinical model. The prognostic value of GDF15 was assessed using our in-house data and externally validated through public databases. Results: 25 RCTs with 4563 EC patients were included in the network meta-analysis. NCRT improved overall survival (OS) compared to NCT (HR: 0.83, 95%CrI: 0.69-0.99) and surgery alone (HR: 0.72, 95%CrI: 0.63-0.82). In vitro studies demonstrated that CAFs promoted EAC chemotherapy resistance and radiotherapy resistance. Transcriptomic analysis revealed the enrichment of GDF15 in the EAC tumor-CAF transwell co-culture system, showing opposite expression patterns between tumor and CAF cells. GDF15 concentration was significantly elevated in the co-culture medium. Knockdown of GDF15 in OE33 and OE19 cells restored treatment sensitivity against chemotherapy and radiotherapy. Similar results were obtained when OE33 and OE19 cells were co-cultured with GDF15-depleted CAFs. In the 3D EAC PDO model, enhanced chemoresistance was observed when PDOs were co-cultured with paired CAFs or cultured in a medium containing human GDF15 recombinant protein. Downstream exploration revealed that GDF15 was involved in AKT pathway activation and mitochondrial oxidative phosphorylation in EAC cells. Moreover, GDF15 expression was significantly higher in the tumor tissue than in adjacent normal tissue in EAC patients (p=0.0056). Low GDF15 mRNA expression was associated with better OS in EAC patients (p=0.025). Notably, GDF15 serum concentration was significantly higher after the CROSS treatment (p<0.0001), and a high serum concentration after the CROSS was an independent risk factor for a poor OS in EAC patients (HR: 3.100, 95%CI: 1.092-8.799, p=0.034). Conclusion: NCRT followed by surgery represents the optimal treatment strategy for managing locally advanced EC patients. The co-culture system of EAC PDOs with paired CAFs offers a viable approach for studying tumor-stroma interactions. CAFs play a crucial role in modulating EAC treatment resistance, with GDF15 partly linking CAFs and EAC communications within the tumor microenvironment. GDF15 exhibits a regulatory role in EAC mitochondrial function and therapy resistance. Moreover, the predictive value of GDF15 serum concentration highlights its potential as a prognostic biomarker in EAC patients.

Item Type:	Thesis (PhD thesis)
Translated abstract:	Abstract Language Durch eine umfassende Literaturanalyse konnte die nach aktuellen Richtlinien empfohlene neoadjuvante Radiochemotherapie (NCRT), gefolgt von einer Operation, als optimale Behandlungsstrategie von Patienten mit lokal fortgeschrittenem Ösophaguskarzinom bestätigt werden. Weiterhin fokussierten wir uns auf molekulare Mechanismen, die zur Behandlungsresistenz gegenüber Chemo- und Strahlentherapie in Ösophagus-Adenokarzinom (EAC)-Zellen führen. Wir generierten erfolgreich tumorassoziierte Fibroblasten (CAFs) und patienten-abgeleitete Organoidmodelle (PDOs) aus Primärgewebe von EAC-Patienten und setzten diese in einem ex vivo Ko-Kultursystem ein. EAC-CAFs spielten eine entscheidende Rolle bei der Förderung der Behandlungsresistenz von EAC-Tumorzellen in verschiedenen Tumor-CAF-Ko-Kultursystemen. Zudem verbesserten EAC-CAFs die mitochondriale Funktion in EAC-Zellen. Weiterhin identifizierten wir GDF15 aus unserer Tumor-CAF-Ko-Kultur durch transkriptomische Analysen. GDF15 ist teilweise an der CAF-vermittelten Behandlungsresistenz beteiligt. Die Depletion von GDF15 führte weiterhin zu Behandlungssensibilisierung und beeinträchtigter mitochondrialer Funktion in EAC-Zellen. Zusätzlich beobachteten wir, dass EAC-CAFs die Progression von EAC-Zellen, teilweise durch Aktivierung des AKT-Signalwegs, förderten, während die Depletion von GDF15 die Aktivierung des AKT-Signalwegs in EAC-Zellen abschwächte. Des Weiteren zeigten wir eine signifikante Zunahme des Serum-GDF15-Spiegels nach der CROSS-Behandlung bei EAC-Patienten, welcher einen unabhängigen Risikofaktor für ein schlechteres Gesamtüberleben darstellt. Die externe Validierung mithilfe öffentlicher Datenbanken bestätigte sowohl eine signifikant höhere GDF15-Expression in Tumorgewebe, im Vergleich zu normalem Ösophagus-Gewebe, als auch einen Zusammenhang zwischen einer hohen GDF15-Expression und einem schlechteren Gesamtüberleben bei EAC-Patienten. German
Creators:	Creators Email ORCID ORCID Put Code Fan, Ningbo ningbo.fan@outlook.com orcid.org/0000-0002-1622-6747 UNSPECIFIED
Contributors:	Contribution Name Email Thesis advisor Bruns, Christiane christiane.bruns@uk-koeln.de Thesis advisor Zhao, Yue yue.zhao@uk-koeln.de
URN:	urn:nbn:de:hbz:38-719335
Date:	10 January 2024
Publisher:	Druck-King
Place of Publication:	Köln
Language:	English
Faculty:	Faculty of Medicine
Divisions:	Faculty of Medicine > Chirurgie > Klinik und Poliklinik für Allgemein-, Viszeral- und Tumorchirurgie
Subjects:	Medical sciences Medicine
Uncontrolled Keywords:	Keywords Language esophageal adenocarcinoma English tumor microenvironment English cancer-associated fibroblasts English GDF15 English organoids English therapy resistance English
Date of oral exam:	12 December 2023
Referee:	Name Academic Title Hillmer, Axel Ph.D. Langer, Thomas Ph.D. Wolf, Jürgen Ph.D.
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/71933