High-throughput screening (HTS) of natural products with triple-negative breast cancer (TNBC) organoids.

Abstract

e12558 Background: Breast cancer is one of the most malignant diseases threatening the health of our society. Triple negative breast cancer (TNBC) is an aggressive histological subtype representing 15–20% of all breast cancers. Comparing with other breast cancer subtypes, TNBC is characterized with limited treatment options and a worse clinical outcome. Resistance to chemotherapies is common for TNBC. Therefore, continuously developing new anti-cancer drugs is of great importance for TNBC. Nature products a source of medicinal leads, but lacking suitable pre-clinical models, which could faithfully reflect in vivo tumor property, prevents these compounds from further characterizing. Now cancer organoids, as a new in vitro 3-D culture technique, were demonstrated to largely retain the biological characteristics of tumors from patients, and potentially served as an ideal platform for drug sensitivity test. Methods: Here we set up system to efficiently establish breast cancer organoids from clinical patients and further test the sensitivity of these organoids to various nature products. Results: A total of 29 TNBC organoid models were established with fresh biopsy or surgery tumor tissues from TNBC patients. Estrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor receptor 2 (HER2) in TNBC PDOs were evaluated with qPCR, western blot, Immunohistochemistry (IHC). A high-throughput cell viability assay was established for identifying lead compounds from a unique collection of 969 natural products. Primary hits were serial diluted and further evaluated for IC50 and percentage of inhibition. Preliminary mechanism of action (MOA) studies was performed with gene reporter assays, western blot and qPCR. Interestingly, organoids derived from paclitaxel resistant TNBC patients also show less sensitivity to paclitaxel in vitro, which indicated a high clinical relevance. Conclusions: Triple negative breast cancer organoid, as a good pre-clinical model largely containing tumor in vivo property, provides an ideal platform for new drug discovery and inhibitor screening. Moreover, serving as in vitro replacements for breast cancer, organoid models make it possible to test drug sensitivity for individual patient to achieve precise and personalize medication.