Cisplatin exhibits superiority over MMC as a perfusion agent in a peritoneal mesothelioma patient specific organoid HIPEC platform.

Peritoneal mesothelioma (PM) is a rare malignancy with poor prognosis, representing about 10-15% of all mesothelioma cases. Herein we apply PM patient-derived tumor organoids (PTOs) in elucidating personalized HIPEC responses to bypass rarity of disease in generating preclinical data. Specimens were obtained from PM patients undergoing cytoreductive surgery with HIPEC. PTOs were fabricated with tumor cells suspended in ECM-hydrogel and treated with HIPEC regimen parameters. Viability and characterization analyses were performed post-treatment. Treatment efficacy was defined as ≥ 50% viability reduction and p < 0.05 compared to controls. From October 2020 to November 2022, 17 tumors from 7 patients were biofabricated into organoids, with 16/17 (94.1%) sites undergoing comparative 37° and 42° treatments with cisplatin and mitomycin C (MMC). Hyperthermic cisplatin and MMC enhanced cytotoxicity which reduced treatment viability by 25% and 22%, respectively, compared to normothermia. Heated cisplatin displayed the greatest cytotoxicity, with efficacy in 12/16 (75%) tumors and an average viability of 38% (5-68%). Heated MMC demonstrated efficacy in 7/16 (43.8%) tumors with an average treatment viability of 51% (17-92.3%). PTOs fabricated from distinct anatomic sites exhibited site-specific variability in treatment responses. PM PTOs exhibit patient and anatomic location treatment responses suggestive of underlying disease clonality. In PM organoids cisplatin is superior to MMC in HIPEC.

Application of immune enhanced organoids in modeling personalized Merkel cell carcinoma research.

Merkel cell carcinoma (MCC) is a rare neuroendocrine cutaneous cancer, with incidence of less than 1/100,000, low survival rates and variable response to chemotherapy or immunotherapy. Herein we explore the application of patient tumor organoids (PTOs) in modeling personalized research in this rare malignancy. Unsorted and non-expanded MCC tumor cells were isolated from surgical specimens and suspended in an ECM based hydrogel, along with patient matched blood and lymph node tissue to generate immune enhanced organoids (iPTOs). Organoids were treated with chemotherapy or immunotherapy agents and efficacy was determined by post-treatment viability. Nine specimens from seven patients were recruited from December 2018-January 2022. Establishment rate was 88.8% (8/9) for PTOs and 77.8% (7/9) for iPTOs. Histology on matched patient tissues and PTOs demonstrated expression of MCC markers. Chemotherapy response was exhibited in 4/6 (66.6%) specimens with cisplatin and doxorubicin as the most effective agents (4/6 PTO sets) while immunotherapy was not effective in tested iPTO sets. Four specimens from two patients demonstrated resistance to pembrolizumab, correlating with the corresponding patient's treatment response. Routine establishment and immune enhancement of MCC PTOs is feasible directly from resected surgical specimens allowing for personalized research and exploration of treatment regimens in the preclinical setting.

Organoid Platform in Preclinical Investigation of Personalized Immunotherapy Efficacy in Appendiceal Cancer: Feasibility Study.

PURPOSE: Immunotherapy efficacy data on appendiceal cancer from clinical trials does not exist, due to appendiceal cancer incidence of 0.97 per 100,000. The goal of this study was to preclinically explore the application of immunotherapy in treating appendiceal cancer in a personalized organoid model. EXPERIMENTAL DESIGN: Patient tumor organoids (PTO) were fabricated using unsorted tumor cells with and without enrichment with patient-matched immune components derived from peripheral blood leukocytes, spleen, or lymph nodes [immune-enhanced PTOs (iPTO)]. Organoids were cultured for 7 days, followed by treatment with immunotherapy (pembrolizumab, ipilimumab, nivolumab), and assessed for treatment efficacy. RESULTS: Between September 2019 and May 2021, 26 patients were enrolled in the study. Successful testing was conducted in 19 of 26 (73.1%) patients, with 13 of 19 (68.4%) and 6 of 19 (31.6%) patients having low-grade appendiceal (LGA) and high-grade appendiceal (HGA) primaries, respectively. Immunotherapy response, with increased expression of granzyme B and cleaved caspase 3 and decreased expression of CK20 and ATP activity, was exhibited in 4 of 19 (21.1%) pembrolizumab-treated and 2 of 19 (10.5%) nivolumab-treated iPTOs. Post-immunotherapy cellular viability, in responding HGA organoids to pembrolizumab, decreased to less than 15% (P < 0.05). LGA iPTO treatment responses were observed in pembrolizumab and nivolumab, with an 8%-47.4% (P < 0.05) viability compared with controls. Ipilimumab showed no efficacy in the examined cohort. CONCLUSIONS: Immunotherapy shows measurable efficacy in appendiceal cancer organoids. Information derived from immunocompetent organoids may be applied in selecting patients for clinical trial enrollment in rare diseases where preclinical models of disease are lacking.