# Investigation of novel signaling protein in 3D and in vivo PDAC models using second generation Ref-1 inhibitors

> **NIH NIH R01** · INDIANA UNIVERSITY INDIANAPOLIS · 2021 · $448,088

## Abstract

PROJECT SUMMARY/ABSTRACT
Five-year survival rate of pancreatic ductal adenocarcinoma (PDAC) still remains at a dismal 10%. This poor
outcome is attributed to PDAC’s complex tumor microenvironment (TME) containing a desmoplastic stroma,
which consists of cancer-associated fibroblasts (CAFs) and a dense extracellular matrix (ECM). This stroma
affects proliferation, invasion and drug resistance of pancreatic cancer cells (PCCs). Unexpectedly, the ablation
of CAFs or targeting of certain ECM proteins in the stroma led to changes that actually accelerated tumor growth
and impaired treatment outcome. To address this challenge, we are pursuing targets that selectively kill PCCs
rather than CAFs. Redox effector factor-1 (Ref-1) is upstream of several key signaling pathways as a regulator
of transcription factors (TFs). Blockade of Ref-1 redox function with our first-generation inhibitor blocks the
activation of key TFs including HIF-1α, NFkB, and AP-1, all of which are implicated in growth and metastasis
signaling in the tumor. However more potent second-generation compounds are necessary to effectively treat
PDAC. We recently synthesized new analogs and obtained data showing that these are more potent with a
significant decrease in tumor cell survival with minimal changes in CAF survival. This selective cancer cell killing
is a novel characteristic of our new analogs, as gemcitabine kills both PCCs and CAFs. The underlying
mechanism and therapeutic efficacy of these compounds are the focus of this proposal. Our overarching goal
is to evaluate second-generation Ref-1 inhibitors for treatment of PDAC by comparing the mechanisms of Ref-1
inhibition in PCCs and CAFs. Our hypothesis is that through inhibition of Ref-1, multiple cancer-associated
pathways are simultaneously and effectively targeted leading to suppression of survival signaling in PCCs while
sparing the CAFs. The heterogeneity and complexity of PDAC poses a significant challenge in screening and
evaluating the efficacy of new compounds on tumors and on stromal components. To overcome these technical
challenges and ultimately lead to new treatments, we will perform mechanistic screening of Ref-1 inhibitors using
newly developed in vitro tumor models based on patient-derived PCCs and CAFs - 1) 3D co-culture spheroids
for screening and tumor-stroma interaction; and 2) a microfluidic tumor-microenvironment-on-chip (T-MOC)
model for mechanistic evaluation. Findings using these novel in vitro systems will be validated with orthotopic
PDAC models. Specific aims are: Aim 1. Investigate the selectivity of Ref-1 signaling and the effects of its
inhibition in PCCs and CAFs using T-MOC models; Aim 2. Characterize the mechanism of Ref-1 inhibition for
second-generation compounds; and Aim 3. Validate the efficacy and pharmacodynamic profiles of Ref-1 analogs
in orthotopic PDAC models. The aims of this proposal will provide invaluable information regarding both the
effectiveness of new Ref-1 analogs in sophis...

## Key facts

- **NIH application ID:** 10297976
- **Project number:** 1R01CA254110-01A1
- **Recipient organization:** INDIANA UNIVERSITY INDIANAPOLIS
- **Principal Investigator:** Melissa L. Fishel
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $448,088
- **Award type:** 1
- **Project period:** 2021-06-01 → 2026-05-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10297976

## Citation

> US National Institutes of Health, RePORTER application 10297976, Investigation of novel signaling protein in 3D and in vivo PDAC models using second generation Ref-1 inhibitors (1R01CA254110-01A1). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10297976. Licensed CC0.

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