Abstract A011: Targeting tumor-associated macrophage vulnerabilities to enhance therapy in pancreatic cancer
Migachelle Romano, Makenna May, Laura Pike, Rachel Kvaal, Christopher H. Lieu, Wells A. Messersmith, Todd M. Pitts, Carlo MarchettiAbstract
Background:
PDAC chemotherapy, including standard-of-care gemcitabine (GEM)/nab-paclitaxel (NP) regimen, is associated with the accumulation of TAMs that are functionally linked to therapeutic resistance and worse prognosis. GEM, but not NP, drives TAM polarization toward an immunosuppressive, M2-like phenotype characterized by preferential reliance on oxidative phosphorylation and suppression of glycolysis. These GEM-conditioned M2-like TAMs are associated with therapy resistance and worse prognosis. The mechanism(s) driving this GEM-mediated TAM reprogramming remain unclear. Our investigation identifies a pivotal role for NLRP3, an intracellular receptor overexpressed in PDAC TAMs following chemotherapy.
Methods:
NLRP3 expression was measured by immunofluorescence in pancreatic tumor specimens obtained from patients undergoing pancreatoduodenectomy, comparing samples from patients who had received neoadjuvant chemotherapy (N=6) with those from treatment-naïve patients (N=6) at the time of resection. To assess the role of NLRP3 in response to GEM-based therapy in vivo, we employed both genetic and pharmacological inhibition of NLRP3 in orthotopic and subcutaneous models of PDAC (KPC). At sacrifice, primary tumors were isolated, and scRNA-seq, metabolomic, and functional investigations were conducted to determine the role of NLRP3 in TAMs polarization and metabolism following chemotherapy.
Results:
NLRP3 expression was significantly increased in tumors from chemotherapy-treated versus untreated patients, predominantly localizing to TAMs (CD68+), with little to no expression in CD68- cells. Buffy coat analysis from the same cohort and paired pre- and post-treatment samples consistently confirmed increased NLRP3 expression following chemotherapy. Collectively, these data demonstrate that PDAC chemotherapy induces NLRP3 expression in TAMs both within the TME and peripherally, across treatment regimens. Strikingly, genetic and pharmacological inhibition of NLRP3 dramatically increased the in vivo efficacy of GEM-based treatment compared to controls. Cellular analysis of the primary tumors revealed that NLRP3 inhibition reduced the frequency of M2-like TAMs (CD68+/CD163+) following treatment. Additionally, scRNA-seq and metabolic analyses demonstrated that NLRP3-deficient TAMs exhibit increased glycolysis and reduced oxidative metabolism, suggesting that NLRP3 mediates critical metabolic properties of immunosuppressive macrophages. Further, imaging analysis revealed co-localization of NLRP3 with the mitochondrial membrane following treatment.
Conclusions:
Our findings suggest that NLRP3 is a key driver of GEM-based therapy-induced TAMs reprogramming, which correlates with PDAC progression and resistance to therapy. Together, these data identify NLRP3 as a key, previously unrecognized regulator of GEM-induced TAM adaptations that contribute to therapy resistance in PDAC. These findings support NLRP3 as a promising, clinically actionable target to enhance chemotherapy efficacy in PDAC patients.
Citation Format:
Migachelle Romano, Makenna May, Laura Pike, Rachel Kvaal, Christopher H. Lieu, Wells A. Messersmith, Todd M. Pitts, Carlo Marchetti. Targeting tumor-associated macrophage vulnerabilities to enhance therapy in pancreatic cancer [abstract]. In: Proceedings of the AACR Conference on Pancreatic Cancer: New Frontiers in Biology and Therapeutic Development; 2026 Sep 25-28; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(18_Suppl_2):Abstract nr A011.