Strategy for Biobanking of Ovarian Cancer Organoids: Addressing the Interpatient Heterogeneity across Histological Subtypes and Disease Stages

Summary

This protocol offers a systematic framework for the establishment of ovarian cancer organoids from different disease stages and addresses the challenges of patient-specific variability to increase yield and enable robust long-term expansion for subsequent applications. It includes detailed steps for tissue processing, seeding, adjusting media requirements, and immunofluorescence staining.

Abstract

While the establishment of an ovarian cancer biobank from patient-derived organoids along with their clinical background information promises advances in research and patient care, standardization remains a challenge due to the heterogeneity of this lethal malignancy, combined with the inherent complexity of organoid technology. This adaptable protocol provides a systematic framework to realize the full potential of ovarian cancer organoids considering a patient-specific variability of progenitors. By implementing a structured experimental workflow to select optimal culture conditions and seeding methods, with parallel testing of direct 3D seeding versus a 2D/3D route, we obtain, in most cases, robust long-term expanding lines suitable for a broad range of downstream applications.

Notably, the protocol has been tested and proven efficient in a great number of cases (N = 120) of highly heterogeneous starting material, including high-grade and low-grade ovarian cancer and stages of the disease with primary debulking, recurrent disease, and post-neoadjuvant surgical specimens. Within a low Wnt, high BMP exogenous signaling environment, we observed progenitors being differently susceptible to the activation of the Heregulin 1 ß (HERß-1)-pathway, with HERß-1 promoting organoid formation in some while inhibiting it in others. For a subset of the patient's samples, optimal organoid formation and long-term growth necessitate the addition of fibroblast growth factor 10 and R-Spondin 1 to the medium.

Further, we highlight the critical steps of tissue digestion and progenitor isolation and point to examples where brief cultivation in 2D on plastic is beneficial for subsequent organoid formation in the Basement Membrane Extract type 2 matrix. Overall, optimal biobanking requires systematic testing of all main conditions in parallel to identify an adequate growth environment for individual lines. The protocol also describes the handling procedure for efficient embedding, sectioning, and staining to obtain high-resolution images of organoids, which is required for comprehensive phenotyping.

Introduction

Clinical management of patients with epithelial ovarian cancer remains challenging due to its heterogeneous clinical presentation at advanced stages and high recurrence rates¹. Improving our understanding of ovarian cancer development and biological behavior requires research approaches that address the patient-specific variability during the course of the disease, treatment response, and histopathological as well as molecular features².

Biobanking, characterized by the systematic collection and long-term preservation of tumor samples derived from ovarian cancer patients along with their clini....

Protocol

Tumor tissue specimens from ovarian cancer surgeries were collected and patient-derived organoids were generated in compliance with the Ethics Committee of LMU University (17-471), adhering to the existing applicable EU, national, and local regulations. Each patient involved in the study has consented in written form. When working with fresh tissue samples, Biosafety Level 2 safety permission and Laminar Flow cabinets are required. Given the potentially infectious nature of the tissue samples, which cannot be ruled out due to the lack of routine testing of relevant infectious diseases, it is necessary to ensure that institutional bio-safety regulations are strictly ad....

Results

After initial tissue dissociation, filtration, and counting, cells are seeded in parallel directly in 3D format, as explained above, as well as the suspension in the flask for brief 2D expansion. In some cases, the transient 2D expansion positively influences the organoid formation, and the long-term line is successfully established via this route while comparative parallel 3D seeding can result in growth arrest (Figure 1). For each donor tissue that is processed, the cells are tested accord.......

Discussion

The designed protocol addresses previous challenges of ovarian cancer organoid biobanking with regard to organoid formation and long-term passage potential and ensures the generation of fully expandable lines from the majority of solid tumor deposits. The surgical collection process of tumor samples to be used for organoid generation significantly impacts yield and expansion potential. Tumor tissue samples can be obtained during various procedures, including multi-visceral surgery, diagnostic laparoscopy, or biopsy. The .......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
100 Sterican 26 G	Braun, Melsungen, Germany	4657683
100 Sterican 27 G	Braun, Melsungen, Germany	4657705
293T HA Rspo1-Fc	R&D systems, Minneapolis, USA	3710-001-01	Alternative: R-Spondin1 expressing Cell line, Sigma-Aldrich, SC111
A-83-01 (TGF-b RI Kinase inhibitor IV)	Merck, Darmstadt, Germany	616454
Advanced DMEM/F-12 Medium	Gibco, Thermo Scientific, Waltham, USA	12634028
Anti-p53 antibody (DO1)	Santa Cruz Biotechnology, Texas, USA	sc-126
Anti-PAX8 antibody	Proteintech, Manchester, UK	10336-1-AP
B-27 Supplement (50x)	Gibco, Thermo Scientific, Waltham, USA	17504-044
Bottle-top vacuum filter 0.2 µm	Corning, Berlin, Germany	430049
CELLSTAR cell culture flask, 175 cm2	Greiner Bio-one, Kremsmünster, Austria	661175
CELLSTAR cell culture flask, 25 cm2	Greiner Bio-one, Kremsmünster, Austria	690160
CELLSTAR cell culture flask, 75 cm2	Greiner Bio-one, Kremsmünster, Austria	658175
Collagenase I	Thermo Scientific, Waltham, USA	17018029
Costar 48-well Clear TC-treated	Corning, Berlin, Germany	3548
Cryo SFM	PromoCell – Human Centered Science, Heidelberg, Germany	C-29912
Cultrex Reduced Growth Factor Basement Membrane Extract, Type 2, Pathclear	R&D systems, Minneapolis, USA	3533-005-02	Alternative: Matrigel, Growth Factor Reduced Basement membrane matrix  Corning, 356231
Cy5 AffiniPure Donkey Anti-Mouse IgG	Jackson Immuno	715-175-151
DAKO  Citrate Buffer, pH 6.0, 10x Antigen Retriever	Sigma-Aldrich, Merck, Darmstadt, Germany	C9999-1000ML
DAPI	Thermo Scientific, Waltham, USA	62248
Donkey anti rabbit Alexa Fluor Plus 555	Thermo Scientific, Waltham, USA	A32794
Donkey anti-Goat IgG Alexa Fluor Plus 488	Thermo Scientific, Waltham, USA	A32814
Dulbecco´s Phosphate-Buffered Saline	Gibco, Thermo Scientific, Waltham, USA	14190-094
Epredia Richard-Allan Scientific HistoGel	Thermo Scientific, Waltham, USA	Epredia HG-4000-012
Falcon 24-well Polystyrene	Corning, Berlin, Germany	351447
Feather scalpel	Pfm medical, Cologne, Germany	200130010
Fetal Bovine Serum	Gibco, Thermo Scientific, Waltham, USA	10270106
Formalin 37% acid free, stabilized	Morphisto, Offenbach am Main, Germany	1019205000
GlutaMAX	Gibco, Thermo Scientific, Waltham, USA	35050038
HEPES (1 M)	Gibco, Thermo Scientific, Waltham, USA	156630080
Human EpCAM/TROP-1 Antibody	R&D systems, Minneapolis, USA	AF960
Human FGF10	Peprotech, NJ, USA	100-26
Human recombinant BMP2	Gibco, Thermo Scientific, Waltham, USA	PHC7146
Human recombinant EGF	Gibco, Thermo Scientific, Waltham, USA	PHG0311L
Human recombinant Heregulin beta-1	Peprotech, NJ, USA	100-03
LAS X core Software	Leica Microsystems		https://webshare.leica-microsystems.com/latest/core/widefield/
Leica TCS SP8 X White Light Laser Confocal Microscope	Leica Microsystems
N-2 Supplement (100x)	Gibco, Thermo Scientific, Waltham, USA	17502-048
Nicotinamide	Sigma-Aldrich, Merck, Darmstadt, Germany	N0636
Omnifix 1 mL	Braun, Melsungen, Germany	3570519
Paraffin
Parafilm	Omnilab, Munich, Germany	5170002
Paraformaldehyd	Morphisto, Offenbach am Main, Germany	1176201000
Pen Strep	Gibco, Thermo Scientific, Waltham, USA	15140-122
Penicillin-Streptomycin (10,000 U/mL)	Sigma-Aldrich, Merck, Darmstadt, Germany	P4333-100
PluriStrainer 400 µm	PluriSelect, Leipzig, Germany	43-50400-01
Primocin	InvivoGen, Toulouse, France	ant-pm-05
Red Blood Cell Lysing Buffer	Sigma-Aldrich, Merck, Darmstadt, Germany	11814389001
Roticlear	Carl Roth, Karlsruhe, Germany	A538.5
Surgipath Paraplast	Leica, Wetzlar, Germany	39602012
Thermo Scientific Nunc Cryovials	Thermo Scientific, Waltham, USA	375418PK
Triton X-100	Sigma-Aldrich, Merck, Darmstadt, Germany	T8787
Trypan Blue Stain	Sigma-Aldrich, Merck, Darmstadt, Germany	T8154
TrypLE Express Enzyme	Gibco, Thermo Scientific, Waltham, USA	12604-013
Tween-20	PanReac AppliChem, Darmstadt, Germany	A4974-0100
Y-27632	TOCRIS biotechne, Wiesbaden, Germany	1254
Zeocin	Invitrogen, Thermo Scientific, Waltham, USA	R25001