Abstract Non-small cell lung cancer (NSCLC) accounts for approximately 85% of all lung cancers. KRAS mutations and LKB1 inactivation commonly occur in NSCLC and are associated with poor prognosis. Several studies enunciate the role of the immune system in lung cancer progression through cancer cells' ability to escape immune surveillance. Therefore, understanding NSCLC progression requires the examination of the molecular mechanisms behind this process. The importance of oxidative phosphorylation (OXPHOS) and mitochondrial metabolism in lung cancer has been continuously emphasized; OXPHOS and mitochondrial biogenesis markers predict low survival in NSCLC patients. Additionally, heme is an essential molecule in the OXPHOS pathway, and previous studies have shown that heme sequestration using heme sequestering protein 2 (HeSP2) arrests tumor progression. HeSP2 can potentially normalize the tumor immune microenvironment (TIME) via multiple mechanisms including the normalization of vessels which may promote immune cell infiltration, the reduction of hypoxia which may promote antitumor immune function, and the reduction of heme levels which potentially decreases the production of immunosuppressive enzymes requiring heme as a cofactor. In this study, control and HeSP2-treated tumors generated from a genetically engineered mouse model LSL-KrasG12D LKB1-/- (LSL-KRASG12D; LKBloxP/loxP; LSL-Luciferase (KLLuc) infected with AdenoCre virus and sacrificed at 10 months were used for immunohistochemical analysis. We examined immune markers under HeSP2 treatment to determine the immune system response to heme targeting and its effects on tumor progression. Results demonstrated that HeSP2 can modulate the tumor immune microenvironment increasing the levels of immune markers, which suggests that heme targeting can potentiate immunotherapy efficacy in lung cancer treatment. Citation Format: Maria del Carmen Chacon Castro, Eranda Berisha, Narges Salamat, Li Zhang. Heme sequestration modulates the tumor immune microenvironment in KRAS mutation/LKB1 inactivation non-small cell lung cancer [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 1653.
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