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A splicing switch from ketohexokinase-C to ketohexokinase-A drives hepatocellular carcinoma formation

A Corrigendum to this article was published on 27 May 2016

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Abstract

Dietary fructose is primarily metabolized in the liver. Here we demonstrate that, compared with normal hepatocytes, hepatocellular carcinoma (HCC) cells markedly reduce the rate of fructose metabolism and the level of reactive oxygen species, as a result of a c-Myc-dependent and heterogeneous nuclear ribonucleoprotein (hnRNP) H1- and H2-mediated switch from expression of the high-activity fructokinase (KHK)-C to the low-activity KHK-A isoform. Importantly, KHK-A acts as a protein kinase, phosphorylating and activating phosphoribosyl pyrophosphate synthetase 1 (PRPS1) to promote pentose phosphate pathway-dependent de novo nucleic acid synthesis and HCC formation. Furthermore, c-Myc, hnRNPH1/2 and KHK-A expression levels and PRPS1 Thr225 phosphorylation levels correlate with each other in HCC specimens and are associated with poor prognosis for HCC. These findings reveal a pivotal mechanism underlying the distinct fructose metabolism between HCC cells and normal hepatocytes and highlight the instrumental role of KHK-A protein kinase activity in promoting de novo nucleic acid synthesis and HCC development.

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Figure 1: hnRNPH1/2 expression switches KHK-C expression to KHK-A expression in HCC cells.
Figure 2: c-Myc-enhanced hnRNPH1/2 expression switches from KHK-C expression to KHK-A expression in HCC cells.
Figure 3: KHK-A phosphorylates PRPS1 at Thr225.
Figure 4: KHK-A-mediated PRPS1 phosphorylation activates PRPS1.
Figure 5: KHK-A promotes de novo nucleic acid synthesis and reduces ROS production.
Figure 6: KHK-A-dependent phosphorylation of PRPS1 promotes hepatocellular tumorigenesis and is associated with the pathogenesis of HCC.

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  • 27 April 2016

    In the original version of this Article, the affiliations for Gilbert Cote, Hongxia Wang and Liwei Wang were incorrect. In addition, in the Acknowledgements section, 'National Science Foundation of China' should have read 'National Natural Science Foundation of China'. These errors have been corrected in all online versions.

References

  1. Havel, P. J. Dietary fructose: implications for dysregulation of energy homeostasis and lipid/carbohydrate metabolism. Nutr. Rev. 63, 133–157 (2005).

    Article  Google Scholar 

  2. Tappy, L. & Le, K. A. Metabolic effects of fructose and the worldwide increase in obesity. Physiol. Rev. 90, 23–46 (2010).

    Article  CAS  Google Scholar 

  3. Lyssiotis, C. A. & Cantley, L. C. Metabolic syndrome: F stands for fructose and fat. Nature 502, 181–182 (2013).

    Article  CAS  Google Scholar 

  4. Ishimoto, T. et al. Opposing effects of fructokinase C and A isoforms on fructose-induced metabolic syndrome in mice. Proc. Natl Acad. Sci. USA 109, 4320–4325 (2012).

    Article  CAS  Google Scholar 

  5. Fong, Z. V. & Tanabe, K. K. The clinical management of hepatocellular carcinoma in the United States, Europe, and Asia: a comprehensive and evidence-based comparison and review. Cancer 120, 2824–2838 (2014).

    Article  Google Scholar 

  6. Chan, S. L. et al. International validation of the Chinese university prognostic index for staging of hepatocellular carcinoma: a joint United Kingdom and Hong Kong study. Chin. J. Cancer 33, 481–491 (2014).

    Article  CAS  Google Scholar 

  7. Zuo, T. T., Zheng, R. S., Zhang, S. W., Zeng, H. M. & Chen, W. Q. Incidence and mortality of liver cancer in China in 2011. Chin. J. Cancer 34, 56 (2015).

    Article  Google Scholar 

  8. Bonthron, D. T., Brady, N., Donaldson, I. A. & Steinmann, B. Molecular basis of essential fructosuria: molecular cloning and mutational analysis of human ketohexokinase (fructokinase). Hum. Mol. Genet. 3, 1627–1631 (1994).

    Article  CAS  Google Scholar 

  9. Hayward, B. E. & Bonthron, D. T. Structure and alternative splicing of the ketohexokinase gene. Eur. J. Biochem. 257, 85–91 (1998).

    Article  CAS  Google Scholar 

  10. Diggle, C. P. et al. Ketohexokinase: expression and localization of the principal fructose-metabolizing enzyme. J. Histochem. Cytochem. 57, 763–774 (2009).

    Article  CAS  Google Scholar 

  11. Asipu, A., Hayward, B. E., O’Reilly, J. & Bonthron, D. T. Properties of normal and mutant recombinant human ketohexokinases and implications for the pathogenesis of essential fructosuria. Diabetes 52, 2426–2432 (2003).

    Article  CAS  Google Scholar 

  12. Lanaspa, M. A. et al. Endogenous fructose production and metabolism in the liver contributes to the development of metabolic syndrome. Nat. Commun. 4, 2434 (2013).

    Article  Google Scholar 

  13. Ishimoto, T. et al. High-fat and high-sucrose (western) diet induces steatohepatitis that is dependent on fructokinase. Hepatology 58, 1632–1643 (2013).

    Article  CAS  Google Scholar 

  14. Mirtschink, P. et al. HIF-driven SF3B1 induces KHK-C to enforce fructolysis and heart disease. Nature 522, 444–449 (2015).

    Article  CAS  Google Scholar 

  15. Yang, W. et al. ERK1/2-dependent phosphorylation and nuclear translocation of PKM2 promotes the Warburg effect. Nat. Cell Biol. 14, 1295–1304 (2012).

    Article  CAS  Google Scholar 

  16. Yang, W. & Lu, Z. Nuclear PKM2 regulates the Warburg effect. Cell Cycle 12, 3154–3158 (2013).

    Article  CAS  Google Scholar 

  17. Kornberg, A., Lieberman, I. & Simms, E. S. Enzymatic synthesis and properties of 5-phosphoribosylpyrophosphate. J. Biol. Chem. 215, 389–402 (1955).

    CAS  PubMed  Google Scholar 

  18. Khorana, H. G., Fernandes, J. F. & Kornberg, A. Pyrophosphorylation of ribose 5-phosphate in the enzymatic synthesis of 5-phosphorylribose 1-pyrophosphate. J. Biol. Chem. 230, 941–948 (1958).

    CAS  PubMed  Google Scholar 

  19. Hove-Jensen, B. Mutation in the phosphoribosylpyrophosphate synthetase gene (prs) that results in simultaneous requirements for purine and pyrimidine nucleosides, nicotinamide nucleotide, histidine, and tryptophan in Escherichia coli. J. Bacteriol. 170, 1148–1152 (1988).

    Article  CAS  Google Scholar 

  20. Nosal, J. M., Switzer, R. L. & Becker, M. A. Overexpression, purification, and characterization of recombinant human 5-phosphoribosyl-1-pyrophosphate synthetase isozymes I and II. J. Biol. Chem. 268, 10168–10175 (1993).

    CAS  PubMed  Google Scholar 

  21. Li, S., Lu, Y., Peng, B. & Ding, J. Crystal structure of human phosphoribosylpyrophosphate synthetase 1 reveals a novel allosteric site. Biochem. J. 401, 39–47 (2007).

    Article  CAS  Google Scholar 

  22. Li, B. et al. Negative feedback-defective PRPS1 mutants drive thiopurine resistance in relapsed childhood ALL. Nat. Med. 21, 563–571 (2015).

    Article  CAS  Google Scholar 

  23. Cunningham, J. T., Moreno, M. V., Lodi, A., Ronen, S. M. & Ruggero, D. Protein and nucleotide biosynthesis are coupled by a single rate-limiting enzyme, PRPS2, to drive cancer. Cell 157, 1088–1103 (2014).

    Article  CAS  Google Scholar 

  24. Mannava, S. et al. Direct role of nucleotide metabolism in C-MYC-dependent proliferation of melanoma cells. Cell Cycle 7, 2392–2400 (2008).

    Article  CAS  Google Scholar 

  25. McMahon, S. B. Control of nucleotide biosynthesis by the MYC oncoprotein. Cell Cycle 7, 2275–2276 (2008).

    Article  CAS  Google Scholar 

  26. Martinez-Contreras, R. et al. hnRNP proteins and splicing control. Adv. Exp. Med. Biol. 623, 123–147 (2007).

    Article  Google Scholar 

  27. Keller, W. The RNA lariat: a new ring to the splicing of mRNA precursors. Cell 39, 423–425 (1984).

    Article  CAS  Google Scholar 

  28. Rauch, J. et al. c-Myc regulates RNA splicing of the A-Raf kinase and its activation of the ERK pathway. Cancer Res. 71, 4664–4674 (2011).

    Article  CAS  Google Scholar 

  29. Zimonjic, D. B. & Popescu, N. C. Role of DLC1 tumor suppressor gene and MYC oncogene in pathogenesis of human hepatocellular carcinoma: potential prospects for combined targeted therapeutics (review). Int. J. Oncol. 41, 393–406 (2012).

    Article  CAS  Google Scholar 

  30. Trinh, C. H., Asipu, A., Bonthron, D. T. & Phillips, S. E. Structures of alternatively spliced isoforms of human ketohexokinase. Acta Crystallogr. D 65, 201–211 (2009).

    Article  CAS  Google Scholar 

  31. Eriksen, T. A., Kadziola, A., Bentsen, A. K., Harlow, K. W. & Larsen, S. Structural basis for the function of Bacillus subtilis phosphoribosyl-pyrophosphate synthetase. Nat. Struct. Biol. 7, 303–308 (2000).

    Article  CAS  Google Scholar 

  32. Willemoes, M., Hove-Jensen, B. & Larsen, S. Steady state kinetic model for the binding of substrates and allosteric effectors to Escherichia coli phosphoribosyl-diphosphate synthase. J. Biol. Chem. 275, 35408–35412 (2000).

    Article  CAS  Google Scholar 

  33. Lim, J. S., Mietus-Snyder, M., Valente, A., Schwarz, J. M. & Lustig, R. H. The role of fructose in the pathogenesis of NAFLD and the metabolic syndrome. Nat. Rev. Gastroenterol. Hepatol. 7, 251–264 (2010).

    Article  CAS  Google Scholar 

  34. Bose, T. & Chakraborti, A. S. Fructose-induced structural and functional modifications of hemoglobin: implication for oxidative stress in diabetes mellitus. Biochim. Biophys. Acta 1780, 800–808 (2008).

    Article  CAS  Google Scholar 

  35. Bunn, H. F. & Higgins, P. J. Reaction of monosaccharides with proteins: possible evolutionary significance. Science 213, 222–224 (1981).

    Article  CAS  Google Scholar 

  36. Wang, Y. et al. Prognostic significance of c-myc and AIB1 amplification in hepatocellular carcinoma. A broad survey using high-throughput tissue microarray. Cancer 95, 2346–2352 (2002).

    Article  CAS  Google Scholar 

  37. Ji, H. et al. EGF-induced ERK activation promotes CK2-mediated disassociation of α-Catenin from β-Catenin and transactivation of β-Catenin. Mol. Cell 36, 547–559 (2009).

    Article  CAS  Google Scholar 

  38. Xia, Y. et al. c-Jun downregulation by HDAC3-dependent transcriptional repression promotes osmotic stress-induced cell apoptosis. Mol. Cell 25, 219–232 (2007).

    Article  CAS  Google Scholar 

  39. Dyballa, N. & Metzger, S. Fast and sensitive colloidal Coomassie G-250 staining for proteins in polyacrylamide gels. J. Vis. Exp. 30, 1431 (2009).

    Google Scholar 

  40. Lu, Z. et al. Activation of protein kinase C triggers its ubiquitination and degradation. Mol. Cell. Biol. 18, 839–845 (1998).

    Article  CAS  Google Scholar 

  41. Kashima, T., Rao, N., David, C. J. & Manley, J. L. hnRNP A1 functions with specificity in repression of SMN2 exon 7 splicing. Hum. Mol. Genet. 16, 3149–3159 (2007).

    Article  CAS  Google Scholar 

  42. Xu, Y. et al. Cell type-restricted activity of hnRNPM promotes breast cancer metastasis via regulating alternative splicing. Genes Dev. 28, 1191–1203 (2014).

    Article  CAS  Google Scholar 

  43. Taus, T. et al. Universal and confident phosphorylation site localization using phosphoRS. J. Proteome Res. 10, 5354–5362 (2011).

    Article  CAS  Google Scholar 

  44. Chen, Z. Y. et al. Dovitinib preferentially targets endothelial cells rather than cancer cells for the inhibition of hepatocellular carcinoma growth and metastasis. J. Transl. Med. 10, 245 (2012).

    Article  CAS  Google Scholar 

  45. Yang, W. et al. Nuclear PKM2 regulates β-catenin transactivation upon EGFR activation. Nature 480, 118–122 (2011).

    Article  CAS  Google Scholar 

Download references

Acknowledgements

We thank B.-F. Pan for technical support and D. Norwood for critical reading of this manuscript. This work was supported by National Cancer Institute grants 2R01 CA109035 (Z.L.) and 1R0 CA169603 (Z.L.), National Institute of Neurological Disorders and Stroke grant 1R01 NS089754 (Z.L.), MD Anderson Support Grant CA016672, the James S. McDonnell Foundation 21st Century Science Initiative in Brain Cancer Research Award 220020318 (Z.L.), 2P50 CA127001 (Brain Cancer SPORE), a Sister Institution Network Fund from MD Anderson (Z.L.; C.-N.Q.), NIH High-End Instrumentation program grant 1S10OD012304-01 (D.H.H.), CPRIT Core Facility Grant RP130397 (D.H.H.), the Odyssey Fellowship from MD Anderson (X.L.), and research grants 81272340 (C.-N.Q.) and 81472386 (C.-N.Q.) from the National Natural Science Foundation of China. Z.L. is a Ruby E. Rutherford Distinguished Professor.

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Authors

Contributions

This study was conceived by Z.L. and X.L.; Z.L. and X.L. designed the study; X.L., X.Q., L.-X.P., Y.J., D.H.H., Y.Z., Y.X., J.-H.L. and G.C. performed experiments; L.W., H.W. and C.-N.Q. provided reagents and technical assistance; Z.L. and X.L. wrote the paper with comments from all authors.

Corresponding author

Correspondence to Zhimin Lu.

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The authors declare no competing financial interests.

Integrated supplementary information

Supplementary Figure 4 Pathways of fructose metabolism, glycolysis, tricarboxylic acid (TCA) cycle-derived fatty acids, and de novo synthesis of nucleotides and nucleic acids from the pentose phosphate pathway (PPP).

Supplementary Figure 5 hnRNPH1/2 expression switches KHK-C expression to KHK-A expression in HCC cells.

(a) Total RNA was extracted from 30 human HCC and paired non-tumor tissue samples. The RT-PCR products were digested by BsmAI and resolved on agarose gels. N, non-tumor tissue; T, tumor tissue. (b) Immunoprecipitation of hnRNPH1/2 (bottom left panel) from Hep3B cells was followed by RT-PCR analysis of hnRNPH1/2-associated RNAs (bottom right panel) with the indicated primers (top panel). (c) Amino acid sequences of hnRNPH1 and hnRNPH2 were aligned. Different amino acids in two proteins are highlighted. (d) Schematic diagram of synthesized pre-mRNAs of AdML and the indicated AdML-KHK exon 3C fused products (left panel). Incubation of the synthesized pre-mRNAs with a Hep3B nuclear extract with or without hnRNPH1/2 depletion was followed by PCR analysis (right panel).

Supplementary Figure 6 KHK-A but not KHK-C phosphorylates PRPS1 at Thr225.

(a) Purified recombinant GST-KHK-A was incubated with immobilized purified recombinant His-PRPS1 or His-PRPS2. An in vitro pulldown assay was performed. Immunoblot analysis was conducted with the indicated antibodies. (b) Schematic diagram of the restriction site of HindIII in PRPS1 cDNA (left panel). Total RNA was extracted from normal hepatocytes and the indicated HCC cells (right panel). (c) The Km of purified GST-KHK-A for fructose with representative plotting of 1/V vs. 1/[fructose] (left panel) or for purified His-PRPS1 with representative plotting of 1/CPM vs. 1/[PRPS1] (right panel) was determined. (d) Hep3 cells were centrifuged and washed with PBS. 100 μl of the cell pellets with removal of PBS were mixed with 900 μl lysate buffer. 10 μl cell lysate was mixed with 10 μl of purified recombinant his-PRPS1 with the indicated concentrations were analyzed by immunoblot assay with an anti-PRPS antibody. (e) Bacterially purified indicated KHK-A and PRPS1 proteins were stained with colloidal coomassie blue. (f) In vitro phosphorylation analysis, SDS-PAGE and autoradiography were performed by mixing purified GST-KHK-A with purified His-PRPS1 or His-PRPS2 in the presence of [γ32P]-ATP. Immunoblot analysis was conducted with the indicated antibodies. (g) Hep3B cells were transiently transfected with a vector expressing the indicated Flag-PRPS proteins. Immunoblot analysis was conducted with the indicated antibodies. (h) GST pull-down analysis was performed by mixing purified immobilized WT GST-KHK-A, GST-KHK-A G257R on glutathione agarose beads with purified His-PRPS1. (i) [γ32P]-ATP was mixed with WT KHK-A or the KHK-A G257R mutant. KHK-A–bound [γ32P]-ATP was measured. The data represent the mean ± SD from n = 3 independent experiments. (j) In vitro phosphorylation assays were performed by mixing purified WT KHK-A or KHK-C with purified PRPS1 in the presence of ATP. Immunoblot analysis was conducted with the indicated antibodies (k) Hep3B cells were cultured in the medium with added fructose with the indicated concentrations. Immunoblot analysis was conducted with the indicated antibodies.

Supplementary Figure 7 Phosphorylated PRPS1 was not regulated by the allosteric regulators.

(a) Activity of bacterially purified WT His-PRPS1 was measured in the presence or absence of phosphate (50 mM) ADP (100 μM). The data represent the mean ± SD from n = 3 independent experiments. (b) The activity of bacterially purified WT His-PRPS1 with or without phosphorylation by GST-KHK-A was measured in the presence or absence of IMP (100 μM), AMP (100 μM), or GMP (100 μM). The data represent the mean ± SD from n = 3 independent experiments. Immunoblot analysis was conducted with the indicated antibodies. (c) The activity of bacterially purified WT His-PRPS1 was measured in the presence or absence of phosphate (50 mM), IMP (100 μM), AMP (100 μM), or GMP (100 μM). The data represent the mean ± SD from n = 3 independent experiments. Immunoblot analysis was conducted with the indicated antibody. (d) Immunoprecipitation analyses with PRPS1 pT225 antibody was performed using Hep3B cell lysates. Immunoblot analysis was conducted with the indicated antibodies. The amount of phosphorylated PRPS1 was quantified. HC represents heavy chain.

Supplementary Figure 8 KHK-A-mediated PRPS1 phosphorylation promotes glucose-derived de novo nucleotide synthesis.

(a) Intracellular IMP levels in lysates of Hep3B cells expressing hnRNPH1/2 shRNA were measured. The data represent the mean ± SD from n = 3 independent experiments. A two-tailed Student’s t test was used. represents P < 0.01 between the cells with or without hnRNPH1/2 depletion. (b) Intracellular IMP levels in lysates of Hep3B cells expressing KHK shRNA with or without reconstituted expression of WT rKHK-A, rKHK-A L83A, or WT rKHK-C were measured. The data represent the mean ± SD from n = 3 independent experiments. A two-tailed Student’s t test was used. represents P < 0.01 between the cells with or without KHK depletion. #represents P < 0.01 between the KHK-depleted cells reconstituted expression of WT rKHK-A and the KHK-depleted cells reconstituted expression of rKHK-A L83A and WT rKHK-C. (c) Intracellular IMP levels in lysates of Hep3B cells expressing PRPS1 shRNA with or without reconstituted expression of WT rPRPS1, rPRPS1 T225A, rPRPS1 A190T were measured. The data represent the mean ± SD from n = 3 independent experiments. A two-tailed Student’s t test was used. represents P < 0.01 between the cells with or without PRPS1 depletion. #represents P < 0.01 between the PRPS1-depleted cells reconstituted expression of WT rPRPS1 and the rPRPS1 T225A. (d,e) Hep3B cells with reconstituted expression of KHK-C or KHK-A were cultured in the presence or absence of fructose (10 mM). The intracellular levels of AT (d) and phosphate (e) were measured. The data represent the mean ± SD from n = 3 independent experiments. A two-tailed Student’s t test was used. represents P < 0.01; NS represents not significant difference between the indicated cells with or without fructose treatment.

Supplementary Figure 9 KHK-A-mediated PRPS1 phosphorylation promotes hepatocellular tumorigenesis and is associated with the pathogenesis of HCC.

(a) The apoptosis of Hep3B and Huh-7 cells with depletion of hnRNP1/2 (left panel), KHK-A (middle panel), and PRPS1 (right panel) and with or without reconstituted expression of the indicated proteins were examined. The data represent the mean ± SD from n = 3 independent experiments. (b) The proliferation rates of Hep3B cells with the depletion of KHK-A and reconstituted expression of the indicated proteins were examined in the presence or absence of added fructose (10 mM) and NAC (2 mM). The data represent the mean ± SD from n = 3 independent experiments. P < 0.05. (c) Lysates of tumors derived from Huh-7 cells with KHK or PRPS1 depletion and with or without reconstituted WT rKHK-A, rKHK-A L83A, WT rKHK-C, WT rPRPS1, or rPRPS1 T225A expression were prepared. Immunoblot analyses with the indicated antibodies were conducted (d) The antibody specificities were validated. Immunohistochemical analysis of the tissues from the tumors derived from Huh-7 cells (left and right panel) or Huh-7 cells with KHK depletion and reconstituted expression of WT rKHK-C (middle panel) with the indicated antibodies was performed in the presence or absence of blocking peptides specific for KHK Exon 3A- or Exon 3C-coded regions or phosphorylated PRPS1 T225. (e) IHC staining of n = 90 human HCC samples with anti-phospho-PRPS1 T225, anti-KHK-A, anti-hnRNPH1/2, and anti-c-Myc antibodies was performed. Chi-square analysis was performed depending on the staining score for each antibody (high staining score 4.1-8.0; low staining score 0-4).

Supplementary Table 1 Multivariate analysis of c-Myc, hnRNPH1/2, KHK-A, and PRPS1 pT225 expression in HCC samples and patient information (Cox regression model).
Supplementary Table 2 The antibody information.
Supplementary Table 3 The PCR primers and shRNA information.

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Li, X., Qian, X., Peng, LX. et al. A splicing switch from ketohexokinase-C to ketohexokinase-A drives hepatocellular carcinoma formation. Nat Cell Biol 18, 561–571 (2016). https://doi.org/10.1038/ncb3338

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