Abstract PO-100: Lorazepam promotes desmoplasia and ischemic necrosis in murine pancreatic ductal adenocarcinoma

The goal of this research is to identify the effect of the GPR68-activator benzodiazepine (BZD) lorazepam on the pancreatic ductal adenocarcinoma (PDA) tumor microenvironment (TME). BZDs are commonly prescribed to PDA patients to treat anxiety and anticipatory nausea prior to chemotherapy. Certain types of BZDs are known to promote off-target activation of GPR68 under acidic conditions. We hypothesize that GPR68-activating BZDs will stimulate pro-fibrotic and pro-inflammatory signaling pathways by cancer-associated fibroblasts (CAFs), producing a more desmoplastic TME that will subsequently constrict the tumor vasculature, decreasing chemotherapeutic efficacy, and ultimately decreasing patient survival. Using a subcutaneous KPC allograft mouse model, we found that lorazepam modified the TME by significantly increasing α-SMA (smooth muscle actin) protein expression, collagen deposition, and ischemic necrosis. Preliminary, we found that treating tumor-bearing KPC mice with lorazepam similarly promoted ischemic necrosis. RNA sequencing of the lorazepam-treated allograft tumors indicated that CAF and ECM-related genes such as PDPN, LOX, SERPINB2, and ITGA11 were significantly upregulated. Pathway analysis revealed that lorazepam treatment promoted pathways related to inflammation, EMT, hypoxia, as well as known GPR68 downstream signaling pathways such as TNF-alpha signaling via NF-kB and IL6/JAK/STAT3 signaling. qRT-PCR of immortalized CAFs treated with lorazepam indicated that IL6 expression is increased by lorazepam in a GPR68-dependent manner at acidic pH, supporting that the promotion of IL6 expression we observed in vivo was likely GPR68 and CAF-dependent. To validate the clinical significance of our work, covariate adjusted analyses of pancreatic cancer patients who received chemotherapy at Roswell Park from 2004-2020 was performed. Patients taking GPR68 activator benzodiazepines versus non-activator benzodiazepines had poorer progression-free survival (HR 6.85(2.12,22.06)), suggesting that GPR68 activation by benzodiazepines may negatively impact survival. Overall, these findings suggest that lorazepam significantly modifies the PDA TME by promoting desmoplasia and ischemic necrosis, due in part to activation of GPR68. Future experimental work will determine if lorazepam negatively impacts survival and chemotherapeutic efficacy. Significance: This research may guide the development of new clinical recommendations for prescribing benzodiazepines to PDA patients, which will likely be applicable to other cancer types. Citation Format: Abigail C. Cornwell, Abdulrahman A. Alahmari, Arwen A. Tisdale, Kathryn Maraszek, Swati Venkat, Michael E. Feigin. Lorazepam promotes desmoplasia and ischemic necrosis in murine pancreatic ductal adenocarcinoma [abstract]. In: Proceedings of the AACR Virtual Special Conference on Pancreatic Cancer; 2021 Sep 29-30. Philadelphia (PA): AACR; Cancer Res 2021;81(22 Suppl):Abstract nr PO-100.