Fig. 2

Reversible HK1-specific effects on the response of TOV-112D cells to metformin. a HK1 but not HK2 deletion induces the strong decline in the alamarBlue absorbance when cultivated with 2 mM metformin in the medium with only 0.4 mM glucose (one-way ANOVA F = 418.5, df = 9, p < 0.001; Student–Newman–Keuls post-test p < 0.001 are indicated by asterisks). b Concentration dependence of the decline in the alamarBlue absorbance in response to metformin treatment of the HK1⁻ or HK2⁻ TOV-112D cells that were cultivated in DMEM with 0.4 mM glucose for 36 h. The differences between the alamarBlue absorbance were tested by one-way ANOVA (F = 407.5, df = 23, p < 0.001); Student–Newman–Keuls post-test p < 0.001 are indicated by asterisks. c Cytostatic effects of the treatment with 2 mM metformin on HK1⁻ but not HK2⁻ or control cells in the presence of 5.5 mM glucose. d–f The NADPH/NADP (d), NAD/NADH (e), and glutathione (f) ratios in metformin-treated HK1⁻ or HK2⁻ TOV-112D cells that were cultivated in DMEM with 0.4 mM glucose for 36 h. The differences in glutathione levels were tested by one-way ANOVA (F = 23.7, df = 29, p < 0.001); Student–Newman–Keuls post-test p < 0.05 are indicated by asterisks. g The glutamine and glutamate ratios in the HK1⁻ or HK2⁻ TOV-112D cells that were cultivated in DMEM with 0.4 mM or 5.5 mM glucose in the presence or absence of 2 mM metformin for 24 h. h The ATP levels in metformin-treated HK1⁻ or HK2⁻ TOV-112D cells that were cultivated in DMEM with altered glucose (5.5 mM or 0.4 mM), glutamine (2 mM or 0 mM) in the presence or absence of 2 mM or 10 mM metformin for 24 h. i Doubling time of the HK1⁻ or HK2⁻ TOV-112D cells that were cultivated in DMEM with glucose replaced with 5.5 mM fructose, maltose, or mannose in the presence or absence of 2 mM metformin. The differences in doubling time were tested by one-way ANOVA (F = 46.6, df = 53, p < 0.001); Student–Newman–Keuls post-test p < 0.05 are indicated by asterisks. j AlamarBlue absorbance relative to that in the medium with 5.5 mM glucose generated by the HK1⁻ or HK2⁻ TOV-112D cells that were cultivated for 24h in DMEM with glucose replaced with 5.5 mM fructose, galactose, mannose, or maltose in the presence or absence of 2 mM metformin. Asterisks indicate p < 0.05 in one-way ANOVA followed by Student–Newman–Keuls post-tests