Abstract 5493: Novel strategy to make KRAS targeted therapies more effective for PDAC treatment
Authors: Bulnes Ana I. , Garcia Orlando , Shaji Poornima , Holla Swathi , Dan Nirnoy , Dhasmana Anupam , Malik Shabnam , Yallapu Murali , Behrman Stephen , Chauhan Subhash , Khan Sheema S. 
Published: April 2023

Introduction: Pancreatic Ductal Adenocarcinoma (PDAC) patients exhibit extremely poor prognosis. KRAS mutation on codon-12 is present in 70-95% of PDAC cases and it drives PDAC growth and progression. Galectin-1 (Gal-1) is present in both PDAC and stromal cells, being involved in tumor microenvironment, immune cell activation and metastasis. Therefore, this study discusses the efficiency of combined inhibition of mutated KRASG12D and Gal-1 inhibition to effectively suppress PDAC growth and progression. For this we have delivered KRASG12D inhibiting siRNA (siKRASG12D) using a superparamagnetic iron oxide nanoparticle (SPION) and a galectin inhibitor.

Methods: SPION nano-formulation was used to deliver siKRASG12D and investigate in conjunction with Gal-1 inhibitor for its anticancer efficacy. Particles were investigated for size, physico-chemical characterization (Dynamic light scattering), hemocompatibility (hemolysis assay) and the complexation of siKRAS (gel retardation assay). Cellular internalization and uptake of the particles were investigated. Anti-cancer efficacy was determined using in vitro functional assays for cell viability (MTT), migration (Boyden chambers), invasion (Matrigel), clonogenicity, tumor spheroid formation, and in a KrasG12D;LSL-Trp53R172H syngeneic mouse model.

Results: Our results demonstrate that SP-siKRAS efficiently internalized in PDAC cells and suppressed KRASG12D as well as its downstream targets, YAP and PDL-1. Combined targeting of siKRAS and Gal-1 inhibited cell proliferation, clonogenicity, migration, and invasion of PDAC cells and tumor spheroid growth in 3D cell models, which recapitulate the heterogeneity and pathophysiology of PDAC. We have used -KrasG12D;LSL-Trp53R172H syngeneic mouse model of PDAC for investigating efficacy of combined SP-siKRAS formulation and galectin-1 inhibitor. Our results showed that the combination treatment inhibited the fibrotic tumor growth and increased survival rate. The combined treatment increased infiltration of total T cell population and CD8+T cells, reduced the population of myeloid-derived suppressor cells (MDSCs) by 50%

(CD45+, CD3-, CD11b+, Ly6C high, Ly6G-) and T-Regulatory cells (Treg) by 57% (FoxP3+CD25+CD45+CD3+) and increased memory T cells by 34% in mice.

Conclusion: This gene therapy targeting KRAS G12D mutation with a Gal-1 inhibition has a potential to modulate the oncogenic network and tumor microenvironment resulting in the repression of growth, metastasis, chemoresistance, and improvement in patient survival. This study will develop a novel sustainable therapeutic approach to target PDAC growth and improve patient survivability.

Citation Format: Ana I. Bulnes, Orlando Garcia, Poornima Shaji, Swathi Holla, Nirnoy Dan, Anupam Dhasmana, Shabnam Malik, Murali Yallapu, Stephen Behrman, Subhash Chauhan, Sheema S. Khan. Novel strategy to make KRAS targeted therapies more effective for PDAC treatment. [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 5493.