A model system that allows for functional assays to assess for DNA damage repair or other subtype relevant defects, activity of the anti-tumor immune response, and prediction of response to therapies targeting functional defects or the immune system is needed for all ovarian cancer subtypes. Organoids are three-dimensional structures derived from human tumor tissue that anatomically and functionally mimic the tumor from which they were derived allowing for functional analysis of the parent tumor. Based on initial work (S. Hill et al.), the Hill lab is able to reproducibly grow patient-derived epithelial ovarian cancer (HGSC, low grade serous, clear cell, and mucinous), borderline, fallopian tube, and ovarian surface epithelium organoids from small biopsies, fluid samples, and large surgical resections. A major project in the Hill lab is to create more complete organoid culture systems, but at this time, we utilize these models to study all aspects of ovarian cancer biology. We are currently utilizing our organoid models with three goals in mind:
1) To utilize organoids for basic science discovery of mechanisms of ovarian cancer development, disease progression, disease heterogeneity across multiple tumor sites, and therapeutic response evolution.
2) To develop and utilize functional assays performed on tumor organoids as predictors of patient response in the clinic to specific therapies.
3) To utilize panels of patient derived organoids of each epithelial ovarian cancer subtype to develop new therapies or rational therapeutic combinations that can target the unique molecular defects present in each patient's unique tumor.
Details about our organoid model generation and assay development are described in the figures below.
Our organoids are all generated using appropriate IRB approved tissue protocols, and for surgical specimens a pathologist harvests tumor and normal tissue for each patient guaranteeing that the correct tissue is being used and ensuring high quality cultures. To collaborate, please contact Dr. Hill about the Hill Lab Ovarian Cancer Organoid Bank.
The above figure illustrates all steps of organoid generation in the Hill lab. When a patient comes to BWH/DFCI with ovarian cancer, she often presents with large pelvic masses and peritoneal carcinomatosis, as shown in the scan above. As a pathologist, Dr. Hill is able to work with her surgical colleagues to meet the surgical specimens from the operating room in our frozen section room at BWH where she harvests tumor tissue from multiple sites for organoid generation. Tumor tissue is brought back to the Hill lab where it is mechanically and enzymatically digested to small cell clumps or single cells. The Hill lab also receives ascites and pleural effusion samples and biopsies which are plated similarly to surgical resection solid tumors. The tumor cells are mixed with Matrigel and plated in tissue culture plates. Special media (Hill et al.) is added to the plates, and the media components are altered based on the type of assays to be performed on the forming organoids. Spherical organoids (as shown in the brightfield image above) form within 3-10 days of plating, which is a unique property of ovarian cancer organoids and allows for rapid functional assessment of the cultures. This also allows for cultures containing a full complement of immune cells to be generated for short term analysis of immuno-oncologic agent response. All organoid cultures are eventually morphologically matched to the parent tumor with the help of our pathology colleagues or by Dr. Hill herself, and also undergo sequencing analysis to confirm molecular matching to the parent tumor. Short term organoids can be used for a variety of functional assays illustrated below, and the cultures can also be maintained for many passages in the long term to aid in studying ovarian cancer biology (see Hill Lab Ovarian Cancer Organoid Bank).
The Hill lab utilizes multiple types of functional assays on each organoid culture to understand ovarian cancer biology and to determine what types of functional assays on what formulation of organoids may be predictive of patient response. The above figure illustrates a subset of the functional assays the Hill lab performs on ovarian cancer organoids. For high grade serous ovarian cancer (HGSC), the Hill lab performs a standard series of DNA damage repair assays including replication combing assays, sensitivity analysis, and analysis of relevant post-damage protein complex activity all to help understand the DNA damage repair capacity and sensitivity of the HGSC organoids to specific DNA damage repair drugs. For other ovarian cancer subtypes, the lab performs subtype specific assays which are relevant to therapeutic response in those subtypes. The lab also performs a series of immunologic assays examining response of short-term co-cultures to immuno-oncologic agents. Our hope is that by utilizing these functional assays to understand tumor biology now, we may develop specific organoid functional assays for each ovarian tumor subtype which can be utilized in the clinic as predictive biomarkers. The Hill lab continues to expand the array of functional assays for each subtype with every new biologic discovery.