Biology subjects

Engle, D. D.

Publications and source records attributed to Engle, D. D..

3 recordsLinked to original sources

bioRxiv2023

The impact of extracellular matrix on the precision medicine utility of pancreatic cancer patient-derived organoids

The use of patient-derived organoids (PDOs) to characterize therapeutic sensitivity and resistance (pharmacotyping) is a promising precision medicine approach. The potential of this approach to inform clinical decisions is now being tested in several large multi-institutional clinical trials. PDOs are cultivated in extracellular matrix from basement membrane extracts (BMEs) that are most commonly acquired commercially. Each clinical site utilizes distinct BME lots and may be restricted due to the availability of commercial BME sources. However, the impact of different sources and lots of BMEs on organoid drug response is unknown. Here, we tested the impact of BME source and lot on proliferation, chemotherapy and targeted therapy drug response, and gene expression in mouse and human pancreatic ductal adenocarcinoma (PDA) organoids. Both human and mouse organoids displayed increased proliferation in Matrigel (Corning) compared to Cultrex (RnD) and UltiMatrix (RnD). However, we observed no substantial impact on drug response when oragnoids were cultured in Matrigel, Cultrex, or UltiMatrix. We also did not observe major shifts in gene expression across the different BME sources, and PDOs maintained their Classical or Basal-like designation. Overall, we find that BME source (Matrigel, Cultrex, UltiMatrix) does not shift PDO dose-response curves and drug testing results, indicating that PDO pharmacotyping is a robust approach for precision medicine.

cancer biology↗

bioRxiv2022

Identification of a distinct ductal subpopulation with self-renewal and differentiation potential from the adult murine pancreas

Pancreatic ducts function to deliver digestive enzymes into the intestines. Upon injury, ducts can become proliferative and contribute to tissue regeneration; however, the identity of the ductal cells that contribute to these processes is unknown. We combined fluorescence-activated cell sorting, a methylcellulose-containing 3-dimensional culture, droplet RNA-sequencing, and a clonal lineage tracing tool to identify and isolate a distinct subpopulation of pancreatic ductal cells that exhibit progenitor cell properties. These ductal cells are unique in that they form tightly-bound clusters (termed FSCmid-high), with an average of 8 cells per cluster. FSCmid-high clusters comprise only about 0.1% of the total pancreas, are tri-potent for duct, acinar and endocrine lineages, and self-renew robustly in vitro. Transcriptomic analysis of FSCmid-high clusters reveals enrichment for genes involved in cell-cell interactions, organ development, and cancer pathways. FSCmid-high clusters express embryonic pancreatic progenitor markers Sox9, Pdx1, and Nkx6-1 at both transcription and protein levels. FSCmid-high clusters are resistant to enzymatic dissociation and survive severe in vivo acinar injury, which induces formation of ductal rosettes that become proliferative within 14 days. Thus, FSCmid-high clusters represent a small subset of ductal cells with progenitor cell properties. These rare progenitor-like duct cell clusters have implications in pancreas regeneration and tumor initiation/progression.

cell biology↗

bioRxiv2021

The autophagy initiating kinase ULK1 is required for pancreatic cancer cell growth and survival

Amongst cancer subtypes, pancreatic ductal adenocarcinoma (PDA) has been demonstrated to be most sensitive to autophagy inhibition, which may be due to unique metabolic rewiring in these cells. The serine/threonine kinase ULK1 forms the catalytic center of a complex mediating the first biochemical step of autophagy. ULK1 directly recieves signals from mTORC1 and AMPK to trigger autophagy under stress and nutrient poor conditions. Studies in genetic engineered mouse models of cancer have revealed that deletion of core downstream autophagy genes (ATG5, ATG7) at the time of tumor iniation leads to a profound block in tumor progression leading to the development of autophagy inhibitors as cancer therapeutics. However, most preclinical studies and all clinical studies have relied on non-specific lysomotropic agents such as chloroquine and its derivatives, whose toxicity and off-target issues preclude further clinical development and which do not represent the impact of solely biochemically disrupting the autophagy pathway. Furthermore, druggable targets in the core autophagy pathway are quite limited, with ULK1 and ULK2 representing the only protein kinases in the pathway. Here we explore the genetic requirement for ULK1 and ULK2 in human PDA cancer cell lines and xenografts, and take advantage of new small molecule ULK1 inhibitors to demonstrate that ULK inhibition can overcome autophagy induction triggered by PDA therapeutics including chemotherapy and MEK inhibition. Finally we show that ULK inhibitors increase MHC Class I in PDA cells, suggestion a potential therapeutic avenue for such agents in combination with checkpoint immunotherapy.

cancer biology↗