Correction to: Nature https://doi.org/10.1038/s41586-019-1340-y Published online 26 June 2019

In the Methods section “Measurement of UDP-Glc, UDP-GlcUA”, we forgot to remove the HPLC method (originally for pre-experiments) from the final version. We apologize for any confusion it may have caused. We also updated the Methods to include a detailed description of sample preparation and mass spectrometry analysis for the metabolites, as below.

Metabolite extraction from cultured cells, tissues and serum

Cultured cells (10 cm dish) were washed with PBS and immediately incubated with 1 ml ice-cold methanol:acetonitrile:water (40:40:20) with 0.5% formic acid on ice for 5 min. Fifty μl 15% NH4HCO3 was then added. The cells were scraped and centrifuged at 15,000g for 10 min at 4 °C. The supernatant was then transferred to a clean tube and evaporated to dryness under nitrogen. The metabolite pellet was redissolved in 200 μl methanol:acetonitrile:water (40:40:20) and centrifuged at 14,000g for 10 min at 4 °C. The supernatant was analysed by liquid chromatography mass spectrometry (LC-MS). Dissected tumour tissues (50 mg) were incubated with 500 μl ice-cold methanol (80%) and then ground with a tissue grinder (OMNI) on dry ice. The sample was vortexed for 1 min at 4 °C and then incubated at –80 °C for 2 h, followed by centrifugation at 14,000g for 20 min at 4 °C. The supernatant was transferred to a clean tube and then lyophilized using a SpeedVac (Labconco). The metabolite pellet was redissolved in 200 μl methanol:acetonitrile:water (40:40:20) and centrifuged at 14,000g for 10 min at 4 °C. The supernatant was analysed by LC-MS. Ice-cold methanol was added to serum (100 μl) to make a methanol solution (80%, v/v). The sample was gently shaken to mix and incubated at –80 °C for 2 h, followed by centrifugation at 14,000g for 10 min at 4 °C. The supernatant was transferred to a clean tube and then lyophilized using a SpeedVac (Labconco). The metabolite pellet was re-dissolved in 200 μl methanol:acetonitrile:water (40:40:20) and centrifuged at 14,000g for 10 min at 4 °C. The supernatant was analysed by LC-MS.

Liquid chromatography mass spectrometry

Chromatographic elution was performed on an Agilent 1290 Infinity System (Agilent Technologies, USA) equipped with a sample manager coupled to a mass spectrometer with an electrospray ion source in negative ion mode. The separation was carried out on a Waters BEH amide column (100 mm × 2.1 mm, 1.7 μm) at 40 °C. The mobile phase A was Ultra-Pure water containing 0.3% ammonia and 15 mM ammonium acetate, and the mobile phase B was acetonitrile/water (9:1) containing 0.3% ammonia and 15 mM ammonium acetate. The flow rate was 0.3 ml min–1, and the gradient of mobile phase A was held at 15% for 1 min, 15% to 45% in 11 min, held at 45% for 2 min, then 45% to 15% in 0.5 min, and finally held at 15% for 1.5 min. The sample volume injected was 5 μl.

Detection was done with an Agilent 6545 Q/TOF-MS system in negative mode. The parameters used were as follows: capillary voltage, 4,000 V; nozzle voltage (Expt), 1,500 V; nebulizer gas, 35 psi; drying gas flow rate, 8 L min–1; and gas temperature, 350 °C. A full scan was run with a mass range from m/z 60 to 1,250 using Extended Dynamic Range 2 GHz. Also, to produce accurate mass correction, an automated calibration delivery system was used to calibrate the MS results automatically by prepared calibration solutions before and during the analysis.

Data processing was done using Qualitative Workflow and Profinder 10.0 software (Agilent). The retention time of UDP-glucose is 6.3 min, and the theoretical monoisotopic mass is 565.0477, the m/z error is within 5 ppm. The retention time of UDP-glucuronic acid is 7.1 min, and the theoretical monoisotopic mass is 579.0270, the m/z error is within 5 ppm. The retention time in both of the samples and standard solutions was consistent.