Abstract 1038: Novel therapy targeting mutant-KRASG12D and galectin-1 in pancreatic cancer
Authors: Martinez Bulnes Ana I. , Shaji Poornima , Dan Nirnoy , Cantu Melida , Malik Shabnam , Behrman Stephen , Holla Swathi , Yallapu Murali Mohan , Jaggi Meena , Chauhan Subhash C. , Khan Sheema 
Published: June 2022

Introduction: In pancreatic ductal adenocarcinoma (PDAC), low patient survival rate remains a problem. The activating point mutation of KRAS on codon-12 is present in 70-95% of PDAC cases and so far, no success has been achieved to inhibit KRAS. KRASG12D regulates cell proliferation, differentiation, apoptosis; recent preliminary and published studies show high Galectin-1 (Gal-1) levels in both PDAC and stromal cells, which modulate tumor microenvironment and metastasis. Therefore, we have developed a novel combination therapy for PDAC by targeting mutated KRASG12D and Gal-1 to target both proliferation and metastasis in PDAC. This includes the delivery of KRASG12D inhibiting siRNA (siKRASG12D) using a superparamagnetic iron oxide nanoparticle (SPION) and a galectin inhibitor.

Methods: Our patented SPION nano-formulation was used to deliver siKRASG12D and investigated 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 mouse model.

Results: Our results demonstrate optimal particle size/zeta potential of SP-siKRAS formulation. 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. It inhibited cell proliferation, clonogenicity, migration, and invasion of PDAC cells. This resulted in activation of death related mechanisms, such as Bax, bcl-2, PARP cleavage in KRASG12D cells. Interestingly, the formulation was highly effective in inhibiting KRASG12D and growth of tumor spheroid in 3D cell models, which recapitulate the heterogeneity and pathophysiology of PDAC. This further provides a clinical validation demonstrating potential of SP-siKRAS particles to efficiently silence KRAS expression. SP-siKRAS also exhibited hemocompatibility and stability suggesting its potential of silencing KRAS without being toxic to the body. The formulation efficiently exhibited KRasG12D silencing and inhibited tumor growth and metastasis in nude 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. Martinez Bulnes, Poornima Shaji, Nirnoy Dan, Melida Cantu, Shabnam Malik, Stephen Behrman, Swathi Holla, Murali Mohan Yallapu, Meena Jaggi, Subhash C. Chauhan, Sheema Khan. Novel therapy targeting mutant-KRASG12D and galectin-1 in pancreatic cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1038.