Abstract 4159: Ovarian cancer ex vivo 3D tumor cultures predict patient specific drug sensitivity

Introduction While systemic treatment has been quite static in the past decade in ovarian cancer, the challenge for the coming years is to stratify patients for optimal and new treatment strategies, such as targeting DNA damage response pathways, or immune modulation. Patient primary tumor from resections, biopsy or ascites can be cultured such that tumor heterogeneity and resident immune cells are preserved. These can be used to predict treatment response in patients or to test new cancer therapies. Here we present a high throughput short-term 3D ex-vivo culture platform combined with high content image-based analysis. This platform allows visualization and quantification of standard of care therapy and new drugs on fresh and cryopreserved patient derived ovarian cancer tumoroids.

Methods Patients with advanced primary or relapsing ovarian carcinoma are included in ongoing multi-center clinical trials in the Netherlands. Ovarian cancer derived tumoroids, freshly isolated or cryopreserved, are embedded in a protein-rich hydrogel and exposed to up to 20 drugs during a short term 3D culture. The automated high content imaging analysis platform measures a large panel of tumoroid morphological features, and responses such as tumor cell killing, growth arrest and local invasion are measured to define the response for each drug. In addition, clinical response data from the ongoing trials are collected to be correlated to clinical outcome of patients treated with systemic therapy.

Results We present results of drug sensitivity testing in patient-derived primary tumor cells of fresh and cryopreserved ascites and solid tumor. Patient-specific drug sensitivity is identified for up to 20 drugs including standard of care (e.g. carboplatin, paclitaxel) and novel treatment strategies (e.g. PARP inhibitors). Activity of immunomodulatory drugs were also monitored successfully in vitro. Accurate response evaluation demonstrates the feasibility of high-throughput drug screening on patient primary material within OcellO's platform. Our results show a high reproducibility in testing freshly isolated or cryopreserved material, highlighting the potential of a cryopreserved collection of patient derived primary material to test new drugs.

Conclusion OcellO's advanced 3D image analysis of patient primary material represents a rapid and biologically relevant approach to test various candidate compounds (e.g. antibodies, antibody-drug conjugates and small molecules) for ovarian cancer. The availability of drug response data combined with patient clinical data, including BRCA mutation and cytology/histology pathologist evaluation is expected to support drug discovery, improve the efficiency of clinical trials and establish predictive testing in the clinical setting.

Citation Format: Fanny Grillet, Abbas Jariani, Juul Overkamp, Lidia Daszkiewicz, Kuan Yan, Leo S. Price, Willemijn Vader. Ovarian cancer ex vivo 3D tumor cultures predict patient specific drug sensitivity [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 4159.

Abstract B139: Patient specific drug sensitivity to novel treatment approaches in ovarian cancer ex vivo 3D tumor cultures

Background: Many new drugs and treatment strategies are in development for ovarian cancer. While systemic treatment has been quite static in the past decade, the challenge for the coming years is to stratify ovarian cancer patients for optimal treatment strategies, like targeting DNA damage response pathways or immune modulatory approaches. Patient primary tumor material collection offers cryopreserved viable primary tumor cell clusters, containing the whole heterogeneity found in the patient ascites (including potential immune cells) to predict treatment response in patients or to test new cancer therapies. Here we present a high throughput short-term 3D ex-vivo culture platform combined with high content image-based analysis. This platform allows visualization and quantification of standard of care therapy and new drugs on fresh and cryopreserved patient derived ovarian cancer tumoroids. Methods: Patients with ovarian carcinoma are included in ongoing multi-center clinical trials in the Netherlands. Ovarian cancer derived primary tumoroids, freshly isolated or cryopreserved, are embedded in a protein-rich hydrogel and exposed to up to 20 drugs during a short term 3D culture. The automated high content imaging analysis platform measures a large panel of tumoroid morphological features, and responses such as tumor cell killing, growth arrest and local invasion are measured to define the response for each drug. In addition, clinical response data from the ongoing trials will be correlated to clinical outcome of patients treated with systemic therapy. Results:We present first results of drug sensitivity in patient-derived primary tumor cells of fresh and cryopreserved ascites. Patient-specific drug sensitivity is identified for up to 20 drugs including standard of care (e.g. carboplatin, paclitaxel) and novel treatment strategies (e.g. PARP inhibitors). Accurate response evaluation demonstrates the feasibility of high-throughput drug screening on patient primary material within OcellO’s platform. Our results show a high reproducibility in testing freshly isolated or cryopreserved material, highlighting the potential of a cryopreserved collection of patient derived primary material to test new drugs. Conclusion: OcellO’s advanced 3D image analysis of patient primary material represents a rapid and biologically relevant approach to test various candidate compounds (e.g. antibodies, antibody-drug conjugates and small molecules) for ovarian cancer. The availability of drug response data combined with patient clinical data, including BRCA mutation and cytology/histology pathologist evaluation is expected to support drug discovery, improve the efficiency of clinical trials and establish predictive testing in the clinical setting.

Citation Format: Fanny Grillet, Abbas Jariani, Juul Overkamp, Lidia Daszkiewicz, Kuan Yan, Leo Price, Willemijn Vader. Patient specific drug sensitivity to novel treatment approaches in ovarian cancer ex vivo 3D tumor cultures [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapeutics; 2019 Oct 26-30; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2019;18(12 Suppl):Abstract nr B139. doi:10.1158/1535-7163.TARG-19-B139

Prolonged re-expression of the hypermethylated gene EPB41L3 using artificial transcription factors and epigenetic drugs

Epigenetic silencing of tumor suppressor genes (TSGs) is considered a significant event in the progression of cancer. For example, EPB41L3, a potential biomarker in cervical cancer, is often silenced by cancer-specific promoter methylation. Artificial transcription factors (ATFs) are unique tools to re-express such silenced TSGs to functional levels; however, the induced effects are considered transient. Here, we aimed to improve the efficiency and sustainability of gene re-expression using engineered zinc fingers fused to VP64 (ZF-ATFs) or DNA methylation modifiers (ZF-Tet2 or ZF-TDG) and/or by co-treatment with epigenetic drugs [5-aza-2'-deoxycytidine or Trichostatin A (TSA)]. The EPB41L3-ZF effectively bound its methylated endogenous locus, as also confirmed by ChIP-seq. ZF-ATFs reactivated the epigenetically silenced target gene EPB41L3 (∼ 10-fold) in breast, ovarian, and cervical cancer cell lines. Prolonged high levels of EPB41L3 (∼ 150-fold) induction could be achieved by short-term co-treatment with epigenetic drugs. Interestingly, for otherwise ineffective ZF-Tet2 or ZF-TDG treatments, TSA facilitated re-expression of EPB41L3 up to twofold. ATF-mediated re-expression demonstrated a tumor suppressive role for EPB41L3 in cervical cancer cell lines. In conclusion, epigenetic reprogramming provides a novel way to improve sustainability of re-expression of epigenetically silenced promoters.