Screening of Conditionally Reprogrammed Patient-Derived Carcinoma Cells Identifies ERCC3–MYC Interactions as a Target in Pancreatic Cancer

Abstract

Purpose Even when diagnosed prior to metastasis, pancreatic ductal adenocarcinoma (PDAC) is a devastating malignancy with almost 90% lethality, emphasizing the need for new therapies optimally targeting the tumors of individual patients. Experimental Design We first developed a panel of new physiological models for study of PDAC, expanding surgical PDAC tumor samples in culture using short-term culture and conditional reprogramming with the Rho kinase inhibitor Y-27632, and creating matched patient-derived xenografts (PDX). These were evaluated for sensitivity to a large panel of clinical agents, and promising leads further evaluated mechanistically. Results Only a small minority of tested agents was cytotoxic in minimally passaged PDAC cultures in vitro. Drugs interfering with protein turnover and transcription were among most cytotoxic. Among transcriptional repressors, triptolide, a covalent inhibitor of ERCC3, was most consistently effective in vitro and in vivo causing prolonged complete regression in multiple PDX models resistant to standard PDAC therapies. Importantly, triptolide showed superior activity in MYC-amplified PDX models, and elicited rapid and profound depletion of the oncoprotein MYC, a transcriptional regulator. Expression of ERCC3 and MYC was interdependent in PDACs, and acquired resistance to triptolide depended on elevated ERCC3 and MYC expression. TCGA analysis indicates ERCC3 expression predicts poor prognosis, particularly in CDKN2A-null, highly proliferative tumors. Conclusion This provides initial preclinical evidence for an essential role of MYC-ERCC3 interactions in PDAC, and suggests a new mechanistic approach for disruption of critical survival signaling in MYC-dependent cancers.

Precision Oncology: The Road Ahead

“…Patient-derived cell lines via CR can be rapidly established [203] and are suitable to screen large drug libraries [204, 205], or to test drug combinations to overcome acquired resistance to targeted therapy [206]. While phenotypic features and the genetic heterogeneity of the original tumor are retained in short term CR cultures, the enrichment of specific cell populations, including non-transformed epithelial cells in this model, requires cross-verification of pheno- and genotypic features of donor tissues and CR cells.…”

Conditional reprogramming and long-term expansion of normal and tumor cells from human biospecimens

“…In tumor CR cell cultures, phenotypic and genotypic features of the primary tumor are maintained 7 and the technique has recently been used to identify an appropriate therapy for respiratory papillomatosis 14 . Therefore, it is clear that potential applications of the CR method are far-reaching, and, as described by independent laboratories, it can be adapted for live biobanking 7 and basic research 15–21 , as well as for diagnostic 22,23 , therapeutic 21,24,25 and regenerative medicine 21,26,27 …”

Establishment of pancreatic cancer cell lines with endoscopic ultrasound‐guided biopsy via conditionally reprogrammed cell culture

“…However, PDX takes many months to establish and is difficult to use for high‐throughput screening in cancer patients . Because of these limitations, a recent patient‐derived cancer cell line model, CRCs, are extensively used in cancer research . CRCs induce the propagation and immortalization of human tumor epithelial cells and generate patient‐specific cell lines within 2 or 4 weeks .…”

“…Until now, several preclinical models have been used for drug sensitivity tests, subtype specific functional analysis, and drug development for various cancers, including PDAC. 3,15,16 Previous studies have reported their results using patient-derived xenografts (PDX) as representative preclinical models. However, PDX takes many months to establish and is difficult to use for high-throughput screening in cancer patients.…”

“…3 Because of these limitations, a recent patient-derived cancer cell line model, CRCs, are extensively used in cancer research. 11,15,17,18 CRCs induce the propagation and immortalization of human tumor epithelial cells and generate patient-specific cell lines within 2 or 4 weeks. 10,11 Considering that small tissues from biopsy can be a source of primary cell lines using the CRC technique, EUS-FNB should also be evaluated as a source of primary cancer cell lines.…”