Epidermal growth factor induces STAT1 expression to exacerbate the IFNr‐mediated PD‐L1 axis in epidermal growth factor receptor‐positive cancers

Abstract

The epidermal growth factor (EGF) receptor (EGFR) overexpressed in many cancers, including lung and head and neck cancers, and is involved in cancer cell progression and survival. PD-L1, increases in tumor cells to evade and inhibit CD8+ T cells, is a clinical immunotherapeutic target. This study investigated the molecular mechanism of EGF on regulating PD-L1 in EGFR-positive cancers and determined potential agents to reduce PD-L1 expression. RNA sequencing (RNAseq) and bioinformatics analysis were performed to determine potential driver genes that regulate PD-L1 in tumor cells-derived tumorspheres which mimicking cancer stem cells. Then, the specific inhibitors targeting EGFR were applied to reduce the expression of PD-L1 in vitro and in vivo. We validated that EGF could induce PD-L1 expression in the selected EGFR-positive cancers. RNAseq results revealed that STAT1 increased as a driver gene in KOSC-3-derived tumorspheres; these data were analyzed using PANTHER followed by NetworkAnalyst. The blockade of EGFR by afatinib resulted in decreased STAT1 and IRF-1 levels, both are transcriptional factors of PD-L1, and disabled the IFNr-STAT1-mediated PD-L1 axis in vitro and in vivo. Moreover, STAT1 knockdown significantly reduced EGF-mediated PD-L1 expression, and ruxolitinib, a JAK1/JAK2 inhibitor, significantly inhibited STAT1 phosphorylation to reduce the IFNr-mediated PD-L1 axis. These results indicate that EGF exacerbates PD-L1 by increasing the protein levels of STAT1 to enforce the IFNr-JAK1/2-mediated signaling axis in selected EGFR-positive cancers. The inhibition of EGFR by afatinib significantly reduced PD-L1 and may be a potential strategy for enhancing immunotherapeutic efficacy.

CD147‐mediated glucose metabolic regulation contributes to the predictive role of 18F‐FDG PET/CT imaging for EGFR‐TKI treatment sensitivity in NSCLC

“…Coincidentally, NSCLC patients with these clinicopathologic factors were inclined to have EGFR‐activating mutations. Consistently, high PD‐L1 expression was likely to be associated with the presence of EGFR‐activating mutations in NSCLC, and increased PD‐L1 expression can be considered an independently negative prognosis indicator for NSCLC . In our study, the cell surface expression of PD‐L1 was high in both the HCC827 sensitive cell line and the H1975 resistant cell line, both of which had an EGFR‐activating mutation (a E476‐A750 deletion mutation in exon 19 for the HCC827 cell line and a L858R point mutation in exon 21 for the H1975 cell line).…”

“…Consistently, high PD-L1 expression was likely to be associated with the presence of EGFR-activating mutations in NSCLC, and increased PD-L1 expression can be considered an independently negative prognosis indicator for NSCLC. [63][64][65] In our study, the cell surface expression of PD-L1 was high in both the HCC827 sensitive suggested that PD-L1 expression could be increased by the CD147mediated promotion of glucose metabolic reprogramming via EGFR signaling conferred by EGFR-activating mutations. Intriguingly, a preliminary study indicated that the metabolic response detected by 18 F-FDG PET/CT was predictive of early response and survival at 1 month after anti-PD1 treatment (nivolumab) in previously treated NSCLC.…”

EGFR‐ERK pathway regulates CSN6 to contribute to PD‐L1 expression in glioblastoma

“…PD‐1/PD‐L1 checkpoint blockades have positively changed the treatment patterns for advanced non‐small cell lung cancer (NSCLC), renal cancer, chronic Hodgkin's lymphoma, gastric cancer, urothelial cancer, cervical cancer, head and neck squamous cell carcinoma, hepatocellular carcinoma, and melanoma 10‐14 . The mechanisms of PD‐L1 expression in cancer cells involve multiple levels, including gene amplification, chromatin modification, transcription, and posttranscription 15‐19 . Oncogenic RAS signaling can upregulate PD‐L1 expression through a mechanism involving messenger RNA (mRNA) stability 17 .…”

“…Oncogenic RAS signaling can upregulate PD‐L1 expression through a mechanism involving messenger RNA (mRNA) stability 17 . Epidermal growth factor (EGF) can exacerbate PD‐L1 expression by increasing the protein levels of STAT1 to enforce the IFNr‐JAK1/2‐mediated signaling axis in cancers 18 . Song et al reported that the inhibition of PTEN upregulated PD‐L1 expression at the protein level, but not at the mRNA level, suggesting that posttranscription regulation is critical in PD‐L1 expression 15 .…”

“…[10][11][12][13][14] The mechanisms of PD-L1 expression in cancer cells involve multiple levels, including gene amplification, chromatin modification, transcription, and posttranscription. [15][16][17][18][19] Oncogenic RAS signaling can upregulate PD-L1 expression through a mechanism involving messenger RNA (mRNA) stability. 17 Epidermal growth factor (EGF) can exacerbate PD-L1 expression by increasing the protein levels of STAT1 to enforce the IFNr-JAK1/2-mediated signaling axis in cancers.…”