Abstract Bryophyllum pinnatum (BP) has been widely used in tropical regions as traditional medicine. It is reported to have antioxidant, immunomodulatory, antidiabetic, anti-inflammatory, antihypertensive, wound healing, cytotoxic, and antitumor-promoting activities. Its major secondary metabolites include bufadienolides, flavonoids, triterpenes, and steroids. Pancreatic cancer is usually symptom-free during development and is advanced by the time of diagnosis with a poor prognosis. BxPC-3 is a pancreatic adenocarcinoma cell derived from a 61-year-old female with adenocarcinoma while PANC-1 is a pancreatic ductal carcinoma cell derived from a 56-year-old male with adenocarcinoma in the head of the pancreas and metastasized to the duodenal wall. Apoptosis is a controlled program cell death process that the body uses to combat cancer development. We previously showed that an aqueous extract of BP effectively modulated apoptosis in glioblastoma U-87 MG brain cancer cells. It also induced apoptosis in colon HCT 116 cancer cells but not in colon CCD 841 CoN normal epithelial cells by modulating the pro-apoptotic and anti-apoptotic proteins. In this study, we used the green/red/blue fluorescent Apoptosis/Necrosis Detection Kit and the Human Apoptosis Antibody Array - Membrane [43 Targets] Test (Abcam) to assess the effect of BP in the induction and modulation of apoptosis on BxPC-3 and PANC-1 cells. Our fluorescent apoptosis data showed that a 2-hour treatment with 1.5 mg and 3.0 mg aqueous extract of BP induced a statistically significant percentage of apoptosis in BxPC-3 and PANC-1 cells (74.0 ± 1.0%, 90.0 ± 1.0% > 14.0% ± 4.0%, p < 0.05; 85.0 ± 3.0%, 96.5 ± 0.5% > 11.5%± 3.5%, p < 0.05) as compared to the negative control respectively. Similar results were obtained with the 4-hour incubation period (57.0 ± 1.0%, 78.5 ± 6.5% > 9.5% ± 2.5%, p < 0.05; 89.0 ± 1.0%, 85.5 ± 5.5% > 18.2% ± 2.0%, p < 0.05). From the antibody array-membrane experiments, modulation of various apoptosis markers by BP such as the pro-apoptotic proteins Bad, Bax, p27, and p53 as compared to the negative controls were revealed; and regulation of anti-apoptotic proteins Bcl-2, IGF-I, and p21 were also observed. These results suggest that BP contains phytochemicals that induce apoptosis in pancreatic adenocarcinoma BxPC-3 and PANC-1 cells via the modulation of various apoptotic protein productions. Further study of their specific modulation effects of apoptosis is warranted to reveal the potential chemopreventive and therapeutic properties of BP against pancreatic cancer. Citation Format: Jasmine Cha, Elim Choi, Jessica Yi, Sarah Wolf, Rekha Isaac, Min S. Kang, Allana Benjamin, Christine Choi, Ryan Hayes, Brian Yuen Yau Wong. Modulation of apoptosis in pancreatic adenocarcinoma BxPC-3 cells and ductal carcinoma PANC-1 cells by aqueous extract of Bryophyllum pinnatum [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2540.