Carvacrol potentiates immunity and sorafenib anti-cancer efficacy by targeting HIF-1α/STAT3/ FGL1 pathway: in silico and in vivo study

Hypoxia and tumor cell immunological escape greatly hinder the hepatocellular carcinoma (HCC) treatment efficiency. This study is designed to investigate the capability of carvacrol (CVR) to enhance sorafenib (SOR) anti-cancer efficacy and modulate anti-HCC immunity. CVR target and biological activities were predicted using Swiss Target Prediction website and PASS web server. UALCAN and LinkedOmics databases were used to examine hypoxia-inducible factor 1-alpha (HIF-1α) expression and the relationship between studied genes and tumor clinical features. Kaplan-Meier plotter (KM plotter) and TISIDB databases were used to illustrate correlation of HIF-1α with HCC prognosis and immune infiltration. The binding affinities of CVR to p300, KAT2B, CREBBP, and Hsp90 were demonstrated by molecular docking. In vivo analysis was performed in male Sprague-Dawley rats. The STAT3, JAK2, and fibrinogen-like protein 1 (FGL1) expressions were assessed by qRT-PCR. FGL1 was determined by ELISA. CD8⁺ T cell number was counted by flow cytometry. HIF-1α was determined by immunohistochemistry. CVR showed an HIF-1α inhibitory potential, which is highly expressed in HCC tissues. Also, elevated HIF-1α expression has been found to be correlated with clinicopathological characteristics, poor survival in HCC patients, and tumor immune cell infiltration. CVR/SOR enhanced liver functions and decreased AFP level. CVR/SOR hindered HCC progression by downregulating STAT3, JAK2, and FGL1. CVR/SOR induced tumor immunity via increasing CD8⁺ T cells. CVR/SOR is a powerful combination for tumor repression and enhancing SOR efficiency in HCC by modulating FGL1. Moreover, CVR/SOR might exert the aforementioned effects through HIF-1α/STAT3/FGL1 pathway.