Abstract 6792: Investigating differential expression of Palladin isoform 3 in 2D and 3D pancreatic cancer cell cultures

Abstract

Abstract Palladin (PALLD) is an actin-binding protein widely expressed in mammalian tissues that modulates cytoskeletal dynamics. Palladin is linked to the progression of breast, pancreatic, and renal cancers. There are at least 9 known isoforms of PALLD but isoforms 3 (iso3) and 4 (iso4) appear most significant in cancer cells and associated fibroblasts. Our goal is to understand iso3 in pancreatic cancer (PC) cell lines grown in various culture environments to shed light on the intricate interplay between culture conditions and gene regulation. Cell models were developed as 3D spheroids from hanging drops after optimizing culture conditions by utilizing a combination of inexpensive methylcellulose (MC) and rat tail collagen viscosity ranges across cell seeding densities. The quality of the developed spheroids was assessed using multiple parameters, like diameter, integrity, and circularity to determine ideal spheroid characteristics. Spheroids that formed at a lower MC viscosity range (350-550 mPa·s) led to peripheral loose cells and a higher viscosity range (7,000-10,000 mPa·s) resulted in elongated shapes. Moderate viscosity ranges (1,000-1,800 mPa·s and 3,500-5,600 mPa·s) consistently produced circular and compact spheroids. Optimal incubation times varied from 72 to 96 hr depending on the cell line. Invasion dynamics within collagen-MC gels revealed that PANC-1 had significantly higher invasion potential compared to BxPC-3 and a control cell line C2C12. RT-qPCR results show that PALLD iso3 was particularly overexpressed in the 3D culture environment of PANC-1, suggesting that elevated PALLD isoform 3 expression may be a characteristic of 3D culture, particularly in invasive PC types. Taken together, the study validates the importance of extracellular viscosity for influencing spheroid characteristics toward generating reproducible 3D spheroids. The investigation also highlights PALLD iso3 as a potentially valuable biomarker for aggressive forms of pancreatic cancer. Citation Format: Sonali Biswas, Jason A. Bush. Investigating differential expression of Palladin isoform 3 in 2D and 3D pancreatic cancer cell cultures [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6792.