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

Figure 3.

Figure 3

Metformin increases infiltration, perforin production, and cytotoxicity of HNSCC NK cells. (A) Immunofluorescence images of HNSCC tumor biopsy before treatment and resection after metformin treatment. Red=pan-cytokeratin, pink=NKG2D, orange=CD3, and blue=DAPI nuclear stain. (B) Quantification of total and infiltrating NK cells within the stained tumor tissue. Patients sourced from Amin et al. (C) Bulk cytokine analysis by IsoLight 24 hours after treatment with vehicle or 12 mM metformin treatment. (D) Cytotoxicity of HNC NK cells co-cultured with target cells treated with 12 mM metformin for 24 hours. Target cells included the established cell lines, CAL-27 which are HPV–, and UMSCC47 which are HPV+, and primary cells are derived from matched HNC tumor tissue from patients. Peripheral NK cells are derived from blood while infiltrating NK cells are derived from tumor-infiltrating lymphocytes. (E) Cytotoxicity of HNC cells compared with healthy donor (NML). (B), (C) and (D) were analyzed by paired student’s t-test. (E) was analyzed by two-way analysis of variance. HNC, head and neck cancers; HNSCC, head and neck are squamous cell carcinoma; HPV, human papilloma virus; IFN, interferon; IL, interleukin; NK, natural killer.