Abstract 1834: Tumor treating fields (TTFields) plus chemotherapy abrogates pancreatic ductal adenocarcinoma (PDAC) proliferation and alters the tumor microenvironment

Abstract Background: TTFields are non-invasive and novel treatment modality that utilizes low intensity, alternating, and intermediate frequency electrical fields to inhibit cancer cell proliferation through a multitude of mechanisms. These include inhibition of mitosis, disruption of cancer cell membranes, metabolomic dysregulation of cancer cells, and immunogenic activation of the tumor microenvironment (TME). TTFields are approved in glioblastoma multiforme, non-small cell lung cancer and malignant mesothelioma. The PANOVA2 trial demonstrated promising efficacy for TTFields when applied together with chemotherapy in patients with PDAC. Mechanisms of TTFields in PDAC need further delineation. We sought to investigate the efficacy of TTFields in vitro and in vivo in PDAC cell lines and mouse models. Preclinical studies were conducted in concert with an going clinical trial (NCT04605913). Experimental Procedures: Utilizing the inovitro apparatus we studied the effect of TTFields (150kHz, intensity 2.9+0.2 V cm RMS, 37ċ, over 72 hrs) in an array of PDAC (Panc1, KPC, Panc2, and AsPC1) and human pancreatic stellate cells (hPSC) cell lines, alone or together with cisplatin (Cis, 0.1μM) or gemcitabine (Gem, 0.01μM), compared to control. Cell viability analysis was conducted in each of the groups. In addition, cell lysates from Panc1 cells from concomitant treatment of TTFields plus Gem were probed for STAT3 and α-SMA to analyze stromal proteins and RAS pathway components (KRAS, P38, P42, and others) were performed via Westen Blot. We also performed RNA sequencing for the different groups to analyze gene expression levels. We further assessed the effect of TTFields (150kHz, intensity 1.8-2 V/cm RMS, over 2 weeks) using the inovivo system with and without chemotherapy (Cis, 0.25 mg/Kg per dose (i.p.) 3 times a week) compared to control in C57BL6 orthotopic murine models (6-7 weeks old C57BL6 mice). Summary of Results: Our analysis revealed statistically significant abrogation of PDAC cancer cell lines for the different groups and hPSC cell viability when compared to control for TTFields monotherapy (p <0.001) and TTFields concomitantly with Gem or Cis (p <0.0001). Western blot analysis demonstrated that TTFields alone and when combined with chemotherapy alters both the stroma and RAS pathways with confirmed downregulation of pSTAT3 and α-SMA and KRAS, P-P38, and P-P42. In vivo analysis revealed significant decrease in tumor volume and weight for the concomitant effect of TTFields + Cis. Conclusion: Our preclinical studies demonstrated the efficacy of TTFields as monotherapy and concomitantly with chemotherapy in PDAC and hPSC cell lines and mouse models. Mechanistic insights from the pre-clinical studies will inform the design of future TTFields studies in PDAC. Citation Format: Hani M. Babiker, Santanu Bhattacharya, Douaa Albelal, Shamit Kumar Dutta, Enfeng wang, Debabrata Mukhopadhyay. umor treating fields (TTFields) plus chemotherapy abrogates pancreatic ductal adenocarcinoma (PDAC) proliferation and alters the tumor microenvironment [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 1834.