267 - Tilting Immunometabolic Balance of Tumor Microenvironment by Targeting ENO1 in KRAS-Mutated Colorectal and Pancreatic Cancers

K. S. C. Chao¹, H. Y. Chang², W. C. Huang², T. T. Yuan², W. T. L. Chen³, T. W. Ke³, J. A. Liang³, W. Z. Hong⁴, and K. C. Y. Huang³; ¹Department of Radiation Oncology, China Medical University Hospital, China Medical University, Taichung, Taiwan, ²HuniLife Biotechnology, Taipei, Taiwan, ³China Medical University, Taichung, Taiwan, ⁴China Medical University Hospital, Taichung, Taiwan

Purpose/Objective(s): KRAS is a key driver gene of multiple cancers as its mutation found in ~40% of colorectal cancers (CRC) and ~90% of pancreatic cancer (PDAC) cases. Although with limited success in G12C-mutated lung cancer, currently, there is no effective therapy for G12D and G12V mutations as the majority of CRC and PDAC fall into this category. Oncogenic KRAS signaling pathway not only involves in cancer metastasis but also drives metabolic reprogramming by upregulating glycolytic enzyme such as enolase 1(ENO1) leading to lactate accumulation causing the immunosuppressive tumor microenvironment (TME), which hinders the therapeutic effect of radiotherapy. In cancer cells, in addition to its enzymatic function, ENO1 also undergoes surface translocation and serves as a plasminogen receptor leading to cancer invasion/metastasis. Here we show that targeting surface ENO1 tilted immunometabolic balance of TME, remodeled macrophage polarization, enhanced radiotherapy effect in KRAS-mutated CRC and PDAC cancers. Materials/

Methods: We first examined the relationship between KRAS status and surface ENO1 in CRC patients (n=300) and PDAC patients (n=150) to determine the prognostic significance of surface expression of ENO1. We then characterized whether targeting ENO1 by a novel therapeutic GMP-compliant ENO1 antibody (HuL001), which has completed a phase 1 safety, tolerability, pharmacokinetics and immunogenicity study in healthy subjects (NCT04540770), could affect the metabolic balance and remodeling TME +/- radiotherapy. We conducted in vitro assay and in vivo animal experiments with syngeneic animal model. Tumors were irradiated upon reaching 100 mm^3 with three 8 Gy fractions. The ENO1 antibody (HuL001, 40mg/kg) was given via intraperitoneal injection every three days. Extracellular flux analyses were performed on tumor cells and CD8 T cells to determine metabolic phenotypic changes.
Results: We found that surface expression of ENO1 was significantly associated KRAS mutations, and negatively correlated with survival outcome in CRC and PDAC patients. KRAS mutation triggered ENO1 surface translocation and promoted lactate release. Blockade of ENO1 by anti-ENO1 antibody reduced the lactate release via interacting with the lactate transporter MCT4. Moreover, combined radiation and ENO1 blockade significantly improved tumor response and remodeled the immune landscape within TME as evidenced by the increase of M1-macrophages infiltration and cytotoxic CD8⁺ T cells aggregation in vivo.
Conclusion: These results showed that oncogenic KRAS triggered surface translocation of ENO1 leading to lactate accumulation in TME. Targeting surface ENO1 not only inhibits cancer invasion/metastasis via blocking plasminogen receptor but also improved therapeutic effect by tilting immunometabolic balance of TME. We are in the process of initiating a phase I/II clinical trial to validate the dosing and efficacy of this immunometabolic approach in KRAS-mutated cancers.