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. 2022 Nov 3;10(11):e005632. doi: 10.1136/jitc-2022-005632

Figure 4.

Figure 4

Metformin reduces CXCL1, activates pSTAT1, and inhibits pSTAT3. (A) RNA sequencing heat map of patient NK cells treated with vehicle or 12 mM metformin for 24 hours resulted in four most significantly downregulated and three most significantly upregulated genes (p value<0.0001 and fold change >1.5). Red indicates upregulated genes while blue indicates downregulated. (B) CXCL1 expression by ELISA in supernatant of HNC peripheral NK cells treated with vehicle or 12 mM metformin for 24 hours. (C) Cytotoxicity assay of HNC peripheral NK cells treated with 12 mM metformin, 50 ng CXCL1, or 10 µM CXCR2 inhibitor navarixin for 24 hours and subsequently co-cultured with CAL-27 target cells at 5:1 ratio. (D) Perforin in supernatant of experiment (C) analyzed by ELISA. (E) Western blot analysis of NK92 cells treated with 12 mM metformin, 50 ng CXCL1, or 10 µM CXCR2 inhibitor navarixin for 24 hours and probed for STAT1, STAT3, and actin. (F) Quantification of blot (E) using ImageJ. (B), (C), and (D) were analyzed by matched one-way analysis of variance. HNC, head and neck cancers; NK, natural killer.