Co-cultures of colon cancer cells and cancer-associated fibroblasts recapitulate the aggressive features of mesenchymal-like colon cancer

Background

Poor prognosis in colon cancer is associated with a high content of cancer-associated fibroblasts (CAFs) and an immunosuppressive tumor microenvironment. The relationship between these two features is incompletely understood. Here, we aimed to generate a model system for studying the interaction between cancer cells and CAFs and their effect on immune-related cytokines and T cell proliferation.

Methods

CAFs were isolated from colon cancer liver metastases and were immortalized to prolong lifespan and improve robustness and reproducibility. Established medium and matrix compositions that support the growth of patient-derived organoids were adapted to also support CAF growth. Changes in growth pattern and cellular re-organization were assessed by confocal microscopy, live cell imaging, and immunofluorescence. Single cell RNA sequencing was used to study CAF/organoid co-culture-induced phenotypic changes in both cell types. Conditioned media were used to quantify the production of immunosuppressive factors and to assess their effect on T cell proliferation.

Results

We developed a co-culture system in which colon cancer organoids and CAFs spontaneously organize into superstructures with a high capacity to contract and stiffen the extracellular matrix (ECM). CAF-produced collagen IV provided a basement membrane supporting cancer cell organization into glandular structures, reminiscent of human cancer histology. Single cell RNA sequencing analysis showed that CAFs induced a partial epithelial-to-mesenchymal-transition in a subpopulation of cancer cells, similar to what is observed in the mesenchymal-like consensus molecular subtype 4 (CMS4) colon cancer. CAFs in co-culture were characterized by high expression of ECM components, ECM-remodeling enzymes, glycolysis, hypoxia, and genes involved in immunosuppression. An expression signature derived from CAFs in co-culture identified a subpopulation of glycolytic myofibroblasts specifically residing in CMS1 and CMS4 colon cancer. Medium conditioned by co-cultures contained high levels of the immunosuppressive factors TGFβ1, VEGFA and lactate, and potently inhibited T cell proliferation.

Conclusion

Co-cultures of organoids and immortalized CAFs recapitulate the histological, biophysical, and immunosuppressive features of aggressive mesenchymal-like human CRC. The model can be used to study the mechanisms of immunosuppression and to test therapeutic strategies targeting the cross-talk between CAFs and cancer cells. It can be further modified to represent distinct colon cancer subtypes and (organ-specific) microenvironments.

Abstract 2822: Maximizing radiotherapy impact: a novel pre-clinical platform for screening of radiosensitizing agents in patient-derived tumor organoids

Introduction: Radiotherapy (RT) is widely used for various cancer types, however, radiotoxicity in healthy neighbouring tissues remains challenging. To optimize effectiveness of current therapeutic regimens, there is a clinical need to enhance radiotherapy-mediated killing by radiosensitizing agents. Radiosensitizers show great potential by accelerating DNA damage, production of free radicals and disturbing cell cycle processes by induction of cytostatic and -toxic effects, but pre-clinical drug efficacy testing methods are limited. Patient-derived organoids (PDOs) have emerged as clinically relevant in vitro screening tools to enable drug discovery for specific mutational and molecular subtypes of many cancer indications. Although some radiosensitizing agents have been identified, potential radiosensitizing effects of standard of care as well as novel anti-cancer drugs remain largely unknown. Here, we present a unique screening platform that enables radiosensitizer discovery by showing in-depth insight in cytostatic-and toxic changes and RT-drug synergy.

Methods: Twelve PDO models from colorectal, pancreas, breast, lung, melanoma, cervical and ovarian tumors were screened for responsiveness to potential radiosensitizing agents using our organoid screening platforms. PDOs were seeded in 384-wells format in suspension or 3D gel (for cell-titer-glo (CTG) or imaging purposes) and compound exposure (three concentrations) was performed prior to irradiation (0, 2, 4, 6, 10 Gy). Cell viability data was obtained using both CTG-based assays and high content imaging (HCI)-based assay. Assay robustness and reproducibility were ensured (Z-scores <0.6, reproducible IC50 values). To assess radiosensitizing effects, data was normalized to non-irradiated control conditions. Morphological changes were assessed using HCI.

Results: Clear differences in radiosensitivity were observed, with six out of twelve PDOs showing sensitivity to 10 Gy RT (<30% viability), one breast, two melanoma and two lung PDOs showing limited sensitivity (47-86% viability) and one ovarian PDO showing no response to RT (98% viability). A wide range of responses to the chemo-irradiation treatments were observed, with oxaliplatin exhibiting radiosensitizing effects in cervical and colorectal PDOs, gemcitabine in cervical PDOs and docetaxel showing radioprotective properties in melanoma PDO.

Conclusion and Discussion: Our novel platform for testing potential radiosensitizing anti-cancer agents holds great promise for advanced drug discovery in a clinically relevant and readily available PDO panel, harbouring a wide range of RT-sensitive to insensitive models. CTG and HCI read-outs offer both fast and in-depth assessment of cytotoxic and cytostatic effects and organoid morphology, creating omnipotent potential for tailored compound screening of radiosensitizers.

Citation Format: Liza Wijler, Jara Garcia, Muntaser Abdulrahman, Linda van Seters, My Nguyen, Annelot Staes, Bram Herpers, Leo Price, Marrit Putker. Maximizing radiotherapy impact: a novel pre-clinical platform for screening of radiosensitizing agents in patient-derived tumor organoids [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2822.

Abstract 198: Pan-cancer assay-ready organoid drug screening with robust, reproducible and clinically-relevant output

Introduction The pharmaceutical industry has mostly relied on 2D cancer cell lines and 3D spheroids for in vitro testing, but poor correlation of pre-clinical and clinical outcomes has driven the development of more predictive models. Patient-derived organoids (PDOs) have emerged as representative in vitro avatars of tumor biology, allowing the generation of biobanks covering a large variety in indications and genetic backgrounds. Here, we assess the robustness of our drug screening platform by testing the reproducibility of our organoid assays within and between organoid batches, read-outs, and different labs. We present an assay-ready organoid platform, allowing short timelines, repeated assays from a single batch of organoids, high throughput assays and large panel screens.

Methods Colorectal, breast, lung, pancreatic, ovarian, cervix and melanoma PDO models were selected for subtype and driver mutation variety, banked in large batches, and preserved in assay-ready format. Outgrowth and drug responses of these batches were compared to those of organoids produced in the classic method. Experiments were executed using automated liquid handling equipment to standardize procedures and increase consistency. Performance of the drug screens were assessed by repeated drug sensitivity testing and by calculating intra- and interplate variability, control variability (CV), Z-factor, assay windows and IC50 values. Moreover, drug responses were tested in both celltiterglo-based and high content imaging-based assays.

Results Assay performance of the organoid drug testing platform was high, with high Z-factors (>0.6), and low intra- and interplate variability (CV <15%) indicating reproducible assays. Both the classic and assay-ready organoid technologies resulted in highly reproducible IC50outputs, also when assays were executed months apart or in different labs. Timelines were shortened from months to weeks, and the reduced logistical burden allows screening of large organoid panels of >50 models. Drug sensitivity testing in our fast-paced panel screening platform distinguished sensitive from partially and insensitive models, illustrating how organoids allow patient stratification.

Conclusion and Discussion The assay-ready organoid technology presented here has further improved our already highly predictive and reproducible organoid drug testing platform. The resulting short timelines and large panel screening capabilities will further unlock the great potential of PDO technology. Using large organoid panels in pre-clinical drug development and in combination with biomarker analysis will allow identification of responsive indications, subtypes, and genotypes, and for early patient stratification. Moreover, as most models presented in our panel screen platform are also available as PDX models, it allows for easy translation into in vivo follow-up studies.

Citation Format: Liza Wijler, Jara Garcia Mateos, My Nguyen, Annelot Staes, Linda van Seters, Lama Alhaj Hasan, Victor Tiroille, Bram Herpers, Leo Price, Mariusz Madej, Michiel Fokkelman, Marrit Putker. Pan-cancer assay-ready organoid drug screening with robust, reproducible and clinically-relevant output [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 198.

Specialized Nutritional Support Improves Muscle Function and Maintains Physical Activity Without Affecting Chemotherapy Efficacy in a Colorectal Cancer Mouse Model

Objectives

Skeletal muscle wasting and fatigue are commonly observed in cancer patients receiving chemotherapy and are associated with reduced treatment outcome and quality of life. Nutritional support may mitigate these side effects, but potential interference with chemotherapy efficacy could be of concern. Here, we investigated the effects of a ω-3-PUFA (EPA and DHA), leucine-enriched, high protein (100% whey), additional vitamin D and prebiotic fibers “Specific Nutritional Composition” (SNC) and chemotherapy on state-of-the-art tumor organoid models and muscle cells and studied muscle function, physical activity, systemic inflammation, and chemotherapy efficacy in a mouse model of aggressive colorectal cancer (CRC).

Methods

Chemotherapy treatment consisted of oxaliplatin and 5-fluorouracil. Tumor formation (caliper) and physical activity (infrared camera's) were assessed over time, while tumor-bearing mice received a diet with or without SNC. Ex vivo muscle performance was determined by myography, muscle fatty acid composition by gas-chromatography, and plasma cytokine levels by Luminex xMAP technology. Patient-derived CRC-organoids and C2C12-myotubes were used to determine whether SNC affects chemotherapy-sensitivity in vitro.

Results

SNC increased the muscle contraction capacity of chemotherapy-treated tumor-bearing mice (P < 0.05), and enriched ω-3 fatty acid composition in muscle without affecting treatment efficacy (P < 0.0001) compared to control tumor-bearing mice. Mice receiving SNC maintained physical activity after chemotherapy and showed decreased systemic inflammation and splenomegaly. Therapeutic response of CRC-organoids was unaffected by SNC nutrients, while C2C12 cell viability and protein synthesis significantly improved.

Conclusions

The results show that specialized nutritional support can be used to maintain muscle function and levels of physical activity during chemotherapy without increasing tumor viability. Therefore, nutritional strategies have potential value in promoting cancer and chemotherapy tolerance.

Funding Sources

This research is part of the SCOPE project (Specialized nutrition to improve outcomes of COlorectal cancer PatiEnts) and is supported by the Province of Utrecht, The Netherlands.