Fig. 4: β-OHB metabolism contributes to cytosolic acetyl-CoA synthesis in vivo and supports tumour growth through both OXCT1 and AACS.
C57BL/6J mice bearing a B16 sgNTC tumour on one flank and a knockout tumour on the other flank were infused with [U-13C]-β-OHB for 6.5 h. a, Plasma β-OHB labelling in mice bearing the indicated knockout tumours. n = 3 mice for each knockout tumour. b, [M+2] and [M+4] fractional labelling of β-OHB in the indicated sgNTC versus knockout tumours. Data are paired between sgNTC and knockout tumours from the same mouse. n = 3 biological replicates for each knockout tumour. c–f, Representative palmitate (16:0) MIDs from n = 1 biological replicate of a mouse bearing an sgNTC tumour versus an sgBdh1 #1 tumour (c), sgOxct1 #1 tumour (d), sgAacs #1 tumour (e) and sgOxct1/Aacs tumour (f). See Extended Data Fig. 8 for additional biological replicates. g,h, [M+2] fractional labelling of cytosolic acetyl-CoA (g) and citrate (h) in the indicated sgNTC versus knockout tumours. Data are paired between sgNTC and knockout tumours from the same mouse. n = 3 biological replicates for each knockout tumour. i, Tumour volumes of the indicated subcutaneous AL1376 tumours in C57BL/6J male mice. sgNTC n = 6 mice, sgBdh1 #1 n = 4 mice, sgOxct1 #1 n = 6 mice, sgAacs #1 n = 4 mice and sgOxct1/Aacs n = 5 mice. j, Endpoint tumour weights of the indicated AL1376 tumours implanted orthotopically in the pancreas in C57BL/6J male mice. sgNTC n = 8 mice, sgBdh1 #1 n = 7 mice, sgOxct1 #1 n = 7 mice, sgAacs #1 n = 8 mice and sgOxct1/Aacs n = 8 mice. k,l, Tumour volumes of the indicated subcutaneous B16 tumours in C57BL/6J male mice. sgNTC n = 6 mice, sgBdh1 #1 n = 6 mice, sgOxct1 #1 n = 5 mice, sgAacs #1 n = 6 mice (k) and sgNTC n = 3 mice and sgOxct1/Aacs n = 4 mice (l). m,n, Tumour volumes of the indicated subcutaneous B16 tumours in C57BL/6J male mice exposed to a control or calorie-restricted diet. sgNTC control n = 6 mice, CR n = 6 mice; sgBdh1 #1 control n = 6 mice, CR n = 6 mice; sgOxct1 #1 control n = 5 mice, CR n = 5 mice; sgAacs #1 control n = 6 mice, CR n = 6 mice (m). sgNTC control n = 3 mice, CR n = 4 mice; sgOxct1/Aacs control n = 4 mice, CR n = 4 mice (n). o, Schematic of β-OHB contribution to cytosolic acetyl-CoA synthesis through both a mitochondrial citrate-dependent route through OXCT1 and a citrate-independent route through AACS. Data are presented as means; error bars, s.e.m (a,i,k–n) or as box-and-whisker plots displaying median, interquartile range (boxes) and minima and maxima (whiskers) (j). Comparisons were made using a two-tailed paired t-test (g,h), a one-way ANOVA (j) or a two-way ANOVA (i,k–n).
