Abstract 1059: Paricalcitol, hydroxychloroquine and gemcitabine promote antitumor effects and modulate immune profile in pancreatic ductal adenocarcinoma
Authors: Ganji Purnachandra Nagaraju , Thomas Beena Elizabeth , Phillips Maggie , Herting Cameron , Ruggieri Amanda , Keilson Jessica Millian , Turgeon Michael Kim , Saraswatula Sisira , Pilcher William , Lesinski Gregory B. , Bhasin Manoj , El-Rayes Bassel F. 
Published: June 2022

Background Pancreatic ductal adenocarcinoma (PDAC) has low (&lt;5%) five-year survival. We hypothesized combined Vitamin D3 (Paricalcitol; Par) and hydroxychloroquine (HCQ) impacts stroma, anti-tumor immunity, and autophagy, thereby sensitizing PDAC to gemcitabine (Gem).

Methods For subcutaneous efficacy, 5-6-week-old female nude mice (n=5/group) were injected with KPC-Luc cells and randomized to: 1) vehicle (PBS), 2) Gem plus HCQ, 3) Gem plus Par, and 4) Gem, HCQ, and Par once tumors were palpable. Gem and Par (twice weekly) were administered via intraperitoneal injection. HCQ was given orally (daily). For orthotropic efficacy and single cell analysis, female C57BL/6J mice (n=6/group) were injected with 2×105 KPC-Luc cells into the pancreas tail. On day 5, animals were randomized to 1) PBS and 2) combined Gem/HCQ/Par as above. Tumors were analyzed via bioluminescent imaging. After 15 days, animals were euthanized, tumors were weighed and dissociated into single cells. High viability samples were used to generate scRNA-Seq libraries using 10X genomics droplet approach.

Results Gem, HCQ, and Par significantly (p&lt;0.001) reduced tumor growth/weight versus controls in both models. Single cell transcriptome profiles of 11,188 cells (controls) and 7,624 cells (Gem/HCQ/Par) were obtained. Split UMAP plots of samples were generated with cell clusters annotated from established gene markers. Eight clusters expressing PDAC-associated genes were designated as PDAC cells. The tumor microenvironment (TME) showed dramatic post-treatment changes with significant decreases in PDAC cells (p=0.007) and increases in B cells, monocytes/macrophages (p=0.0006, 0.03 respectively), and increased T/NK cells in treated versus control mice. Supervised analysis among T cells showed more activation (Cd44, Tnfrsf4/9) and exhaustion (Ctla4, Lag3, Pdcd1) associated gene expression post-treatment, indicating robust T cell response. ssGSEA analysis showed significant (p&lt;.001) activation of Th1/Th2/Th17 pathways. Monocyte/macrophages clusters analysis revealed greater expression of M1 genes and M2 genes in treated and control samples, respectively. Modified EMT was observed in stromal cells with enhanced MHC1 expression.

Conclusion HCQ and Par enhance the efficacy of Gem in two mice PDAC models. Single cell transcriptome analyses revealed the combination treatment promoted immune shifts in the PDAC TME. Effects of Par and HCQ and standard chemotherapy drugs, Gem and nab-paclitaxel are being studied in an ongoing clinical trial (NCT04524702).

Citation Format: Purnachandra Nagaraju Ganji, Beena Elizabeth Thomas, Maggie Phillips, Cameron Herting, Amanda Ruggieri, Jessica Millian Keilson, Michael Kim Turgeon, Sisira Saraswatula, William Pilcher, Gregory B. Lesinski, Manoj Bhasin, Bassel F. El-Rayes. Paricalcitol, hydroxychloroquine and gemcitabine promote antitumor effects and modulate immune profile in pancreatic ductal adenocarcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1059.