br may predominantly be causing side
may predominantly be causing side effects with little therapeutic response.
We observed that the huTGO1 and huTGO2 organoid lines expressed HER2, whereas huTGO4 and huTGO6 did not express this Cefepime protein (Figure 6A). This observation was contradictory to the pathologist’s observations of the tumor tissue that reported all patients to be negative for HER2. The patient from whom huTGO1 was derived did not undergo tumor resection, but rather HER2 status was determined on the basis of tissue collected from the met-astatic tumor. We tested whether HER2 inhibition sensi-tized the huTGOs to epirubicin, oxaliplatin, and 5-FU treatment (Figure 6B–E). For example, huTGO1 was most resistant to epirubicin (IC50, 17.66 ± 0.09), oxaliplatin (IC50, 31.57 ± 0.06), and 5-FU (IC50, 13.88 ± 0.07) (Figure 6B, Figure 7). However, when huTGO1s were pretreated with HER2 inhibitor, the IC50 decreased to 6.05
reproduce the effects that trastuzumab has on host immune surveillance.12 Including the patient’s immune cell in an organoid co-culture is part of our future plans. Thus, we may propose that on the basis of our observations, patient-derived gastric cancer organoids may serve as a platform for testing the efficacy of targeted therapies in individual patients.
164 Steele et al Cellular and Molecular Gastroenterology and Hepatology Vol. 7, No. 1
Figure 1. Morphologic differences and proliferative rate of patient-derived gastric cancer organoids (huTGOs). (A) Light micrographs of patient-derived gastric cancer organoid lines. (B) H&E staining of gastric cancer organoids. (C) Proliferation of huTGO lines as measured by EdU (red) uptake (Hoechst, cyan). (D) Quantification of proliferation as measured by %EdU expressing cells/total cell number in huTGOs. *P < .05 compared with huTGO1; n ¼ 6 individual organoids were quantified per line.
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Figure 2. Morphologic
differences and prolifera-tive rate of patient-derived gastric organoids (huFGOs). (A) Light micro-graphs of patient-derived gastric organoid lines. (B) H&E staining of gastric organoids. (C) Proliferation of huFGO lines as measured by EdU (red) uptake (Hoechst, cyan). (D) Quantification of prolifera-tion as measured by % EdU expressing cells/total cell number in huFGOs. *P < .05 compared with huTGO1; n ¼ 6 individual organoids were quantified per line.
Patient-Derived Gastric Cancer Organoids Phenotypically Resemble the Native Tumor Tissue
In support of carcinogenesis, these cultures also rapidly developed tumors in an in vivo xenograft mouse model (Figure 11A). We questioned the extent to which huTGOs
recapitulate their original tumor histology in vivo. HuTGO1 and 2 were xenotransplanted subcutaneously into NSG mice (Figure 11B and C). Notably, histologic and differentiation patterns of the patient tumor tissue were highly recapitu-lated in the xenograft tumors established from the
166 Steele et al Cellular and Molecular Gastroenterology and Hepatology Vol. 7, No. 1
Figure 3. Drug responses of patient-derived gastric cancer and normal orga-
noids. Dose-response curves generated from
patient-derived (A–C) gastric cancer (huTGO) and (D–F) normal (huFGO) organoid lines treated with epirubicin, oxaliplatin, or 5-FU. These plots demon-strate the percent of viable cells as measured by an MTS assay in response to micromolar doses of chemotherapeutic agents. Each assay was run in triplicate for each individ-ual organoid line.
organoids (Figure 11B and C). For example, huTGO2 derived from well-differentiated intestinal-type gastric adenocarci-noma is composed of glandular structures (Figure 11C, PDX-huTGO2) and is similar to patient’s specimen (Figure 11C, P-huTGO2). Organoids derived from mixed poorly differ-entiated diffuse and intestinal-type gastric cancer tissues (huTGO1) formed similar morphologies in vivo including infiltrating single tumor cells (diffuse-type) and adjacent cancer glands (intestinal-type) (Figure 11B, PDX-huTGO1).
Patient-Derived Gastric Cancer Organoids Engraft Within the Gastric Epithelium of a Mouse and Form Adenocarcinoma
Investigating the impact of the endogenous environment of the stomach on tumor growth is part of our future research plans. Thus, we sought to develop an orthotopic transplantation model using patient-derived gastric cancer organoids. HuTGO1 and 2 organoid lines were transplanted
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Figure 4. IC50 values for huTGO and huFGO dose-response curves. IC50 values for tumor-derived gastric organoids (huTGO) treated with (A) epirubicin, (B) oxaliplatin, and (C) 5-FU. IC50 values for normal gastric tissue (huF-GOs) treated with (D) epi-rubicin, (E) oxaliplatin, and (F) 5-FU. CI, confidence interval.
into the submucosa of the gastric epithelium of NSG mice (Figure 11D–F). After organoid transplantation we observed the development of adenocarcinoma with areas of cells invading the epithelium (Figure 11D–H). Of note, human cells were detected in areas of adenocarcinoma and the epithelium of the mouse gastric mucosa with the use of an