PMC

Three samples from each diet group were loaded as indicated at the top (SD, CR-SD, KD and CR-KD). Representative subunits of CI-CV were probed as given on the left. Both cell types show consistent strong downregulation of CII, with the other complexes being relatively more preserved at the protein level. GAPDH is shown as loading control. As controls (cont1 and cont2), kidney cortex was used as described in []. Quantification of loading adjusted staining intensities is given in .

CR reduces proliferation in both cell lines whereas KD caused no reduction of proliferative activity in the SK-N-BE(2) xenograft group. A) shows a representative SD Ki-67 staining pattern in comparison to the CR-KD pattern (B) in SK-N-BE(2) tumor samples. For SH-SY5Y xenografts, PHH3 staining is depicted in D) and E) for SD and CR-KD treatment, respectively. Results are given as mean ± SEM. Statistics: ANOVA (p <0.05) followed by Dunnett’s test correcting for multiple comparisons. Diet groups are compared to the corresponding SD. * p≤0.05; ** p≤0.01; *** p≤0.001.

IHC staining of NB sections were scored on a scale from 0–3 as described in the methods section. The CR-KD group showed a significant decrease in complex I staining. All other evaluated parameters were unaffected by dietary changes. Voltage-dependent ion channel (VDAC) protein levels are used as a surrogate marker of mitochondrial mass. Statistics: ANOVA (p <0.05) followed by two-tailed Dunnett’s test correcting for multiple comparisons. Diet groups are compared to the corresponding SD group.

Both cell types SH-SY5Y A) and SK-N-BE(2) C) show consistent low copies of the mitochondrial genome (mean <150). Panels B) SH-SY5Y and D) SK-N-BE(2) show mean complex II (succinate dehydrogenase) enzyme activities in xenografts of the different diet groups. Enzyme activities of all individual OXPHOS complexes are additionally given in the and Figs. No significant differences were detected between the different diet groups. For the SK-N-BE(2) xenografts, only representative samples were measured (n≥5). Statistics: ANOVA (p <0.05) followed by two-tailed Dunnett’s test correcting for multiple comparisons. Diet groups are compared to the corresponding SD group. The gray bars represent control values from kidney cortex tissue as reported previously [].

After establishing tumors on the right flank of CD-1nu mice, the mice were randomized to diet groups as indicated. Tumor volume was measured twice weekly. A) For SH-SY5Y xenografts at day 19, the tumors of all diet groups showed significant growth inhibition compared to the SD group (CR-SD p = 0.001, KD p<0.001, CR-KD p<0.001). B) At day 33, SK-N-BE(2) tumor growth was significantly inhibited by CR (CR-SD p = 0.040, CR-KD p = 0.004). Inhibition of tumor growth was less pronounced in the KD group (p = 0.918). C) SH-SY5Y and D) SK-N-BE(2) show the results of Kaplan-Meier survival analysis of the corresponding treatment groups. Survival of mice with SH-SY5Y tumors at day 22 on SD was 0% compared to 75% on CR-SD (p<0.001), 50% on KD (p<0.001) and 100% on CR-KD (p<0.001). Survival of mice with SK-N-BE(2) xenografts at day 33 on SD was 36% compared to 83% on CR-SD (p = 0.017), 73% on KD (p = 0.09) and 100% on CR–KD (p<0.001). A, B) Data points for tumor growth curves represent mean values ± SEM of the corresponding diet group (n = 8–11). Statistics: ANOVA (p<0.05) followed by two-tailed Dunnett’s test correcting for multiple comparisons. C, D) Survival is expressed by the Kaplan–Meier method and differences between groups were determined in a univariate analysis with the log-rank test. Death is coded: tumor volume above 3000 mm³, tumor ulceration or impaired health condition. Diet groups are compared to the corresponding SD. * p≤0.05; ** p≤0.01; *** p≤0.001.