Abstract A007: Expression and activity of Rac, Cdc42, and their downstream effector PAK in Puerto Rican pancreatic cancer patients

Abstract

Abstract Pancreatic ductal adenocarcinoma (PDAC) is often diagnosed after the localized tumor has metastasized, which decreases its survival rate to a grim 3%. Mortality from PDAC is also increasing in Puerto Rico with lower survival rates than in the US. Therefore, it is pivotal to identify viable targets for the late stages of PDAC. The small GTPase Ras is the most mutated oncogene in PDAC. Oncogenic Ras, as well as multiple oncogenic cell surface receptors, activate the related GTPases Rac and Cdc42, which in turn activate p21-activated kinase (PAK) by autophosphorylation (p-PAK), to drive cancer cell invasion, and thus metastasis. Rac and Cdc42 are overexpressed in 21% of PDAC patients and contribute to poor prognosis. To determine the feasibility of treating PDAC with Rac/Cdc42 inhibitors that we are developing, this study aims to identify the p-PAK levels and Rac/Cdc42 expression in PDAC tissue from Puerto Rican patients. The hypothesis is that p-PAK levels, as well as Rac/Cdc42 expression, are selectively elevated in high-grade invasive PDAC. Immunohistochemistry for p-PAK and immunofluorescence for Rac/Cdc42 were conducted in fixed, paraffin-embedded PDAC biopsy samples of Puerto Rican patients. Preliminary results demonstrate that higher p-PAK levels are correlated with stage 3 and stage 4 tissue, and Rac and Cdc42 are expressed in ductal regions of PDAC tissue. Taken together, p-PAK has potential as a diagnostic biomarker for high-grade PDAC and will aid patient stratification in the planned clinical trials for our lead Rac/Cdc42 inhibitor, MBQ-167. Citation Format: Anamaris Torres-Sanchez, Jahdiel Berrios-Rodriguez, Jerry Cruz-Rodriguez, Jasmin Contreras-Santini, Victor Carlo, Suranganie Dharmawardhane. Expression and activity of Rac, Cdc42, and their downstream effector PAK in Puerto Rican pancreatic cancer patients [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Pancreatic Cancer; 2023 Sep 27-30; Boston, Massachusetts. Philadelphia (PA): AACR; Cancer Res 2024;84(2 Suppl):Abstract nr A007.