# Longitudinal Circulating Tumor Cell Collection, Culture, and Characterization in Pancreatic Adenocarcinomas

## TL;DR

This study shows how tracking and analyzing cancer cells in the blood of pancreatic cancer patients can reveal key pathways involved in treatment resistance and help guide personalized therapies.

## Contribution

The study introduces a novel approach for longitudinal collection, culture, and characterization of CTCs in pancreatic cancer to uncover resistance mechanisms.

## Key findings

- CTC cultures revealed activation of TNFα/NF-kB, hedgehog, and EMT pathways linked to PDAC progression and resistance.
- Longitudinal analysis showed dynamic changes in chemoresistance pathways like PI3K/Akt/mTOR and TGF-β.
- Patient-specific gene expression patterns suggest potential for precision medicine in PDAC treatment.

## Abstract

This research focuses on pancreatic adenocarcinomas and takes advantage of novel unbiased culture and characterization models to evaluate circulating tumor cells (CTCs). By collecting and growing CTCs from patients, this study highlights the importance of certain molecular pathways, such as TNF/NF-kB and hedgehog signaling, in cancer progression and treatment failure. These insights could help personalize treatments by identifying specific genetic changes in tumors, making therapies more targeted and effective. This study demonstrates the promise of liquid biopsies for monitoring cancer and shaping future treatment strategies.

Background/Objectives: Pancreatic adenocarcinoma (PDAC) remains one of the most lethal cancers, with limited advancements in treatment efficacy due to high rates of chemoresistance. Circulating tumor cells (CTCs) derived from liquid biopsies offer a non-invasive approach to monitoring tumor evolution and identifying molecular mechanisms of resistance. This study aims to longitudinally collect, culture, and characterize CTCs from PDAC patients to elucidate resistance mechanisms and tumor-specific gene expression profiles. Methods: Blood samples from 10 PDAC patients were collected across different treatment stages, yielding 16 CTC cultures. Differential gene expression, pathway dysregulation, and protein–protein interaction studies were utilized, highlighting patient-specific and disease progression-associated changes. Longitudinal comparisons within five patients provided further insights into dynamic molecular changes associated with therapeutic resistance. Results: CTC cultures exhibited the activation of key pathways implicated in PDAC progression and resistance, including TNFα/NF-kB, hedgehog signaling, and the epithelial-to-mesenchymal transition. Longitudinal samples revealed dynamic changes in signaling pathways, highlighting upregulated mechanisms of chemoresistance, including PI3K/Akt/mTOR and TGF-β pathways. Additionally, protein–protein interaction analysis emphasized the role of the immune system in PDAC progression and therapy response. Patient-specific gene expression patterns therefore suggest potential applications for precision medicine. Conclusions: This proof-of-concept study demonstrates the feasibility of longitudinally capturing and analyzing CTCs from PDAC patients. The findings provide critical insights into molecular drivers of chemoresistance and highlight the potential of CTC profiling to inform personalized therapeutic strategies. Future large-scale studies are warranted to validate these findings and further explore CTC-based approaches in PDAC management.