近年，癌症代謝已成為一個重要的研究領域，尤其研究脂質積累(lipid accumulation)與癌症惡化之間的關係。之前已證實大量表現IGFBP3 (insulin-like growth factor binding protein 3) 增強口腔癌細胞(OEC-M1) 細胞移動和淋巴轉移能力。通過免疫螢光染色，我們觀察到大量表現IGFBP3細胞(OEC-M1 IGFBP3)中的油滴(lipid droplet)量高於對照細胞(OEC-M1 PB)。經由GSEA (geneset enrichment analysis)分析發現脂肪酸代謝(fatty acid metabolism) 和IGFBP3表現量有相關。藉由西方墨點實驗(western blot)，證實大量表達IGFBP3活化ERK (extracellular regulated protein kinase)-AMPK (5' adenosine monophosphate-activated protein kinase)-ACC (acetyl-CoA carboxylase)信號。PD98059 (mitogen-activated protein kinase kinase inhibitor)抑制劑處理大量表達IGFBP3細胞(OEC-M1 IGFBP3)中檢測到脂質油滴累積累減少。此外，使用wound healing分析，油滴形成抑製劑(Tracisin C)或PD98059可抑制IGFBP3增強的細胞爬行能力。我們的結果顯示IGFBP3可通過ERK-AMPK-ACC信號路徑調節脂質油滴累積增強細胞移動活性。

Cancer metabolism has emerged as an important research area in recent years, especially in investigation of the relationship between lipid droplet accumulation and cancer malignancy. Previously, we have demonstrated that insulin-like growth factor binding protein 3 (IGFBP3) enhanced cell migration and lymph node metastasis in IGFBP3 overexpressing OSCC cells (OEC-M1 IGFBP3). By immunofluorescence , we observed the higher amount of lipid droplet (LD) in OEC-M1 IGFBP3 cells than that in the control cells (OEC-M1 PB). By geneset enrichment analysis (GSEA), we found that the pathway of fatty acid metabolism were associated with the IGFBP3 level. By western blot, we demonstrated that the ectopic expression of IGFBP3 activated the ERK (extracellular regulated protein kinase)-AMPK (5' adenosine monophosphate-activated protein kinase)-ACC (Acetyl-CoA carboxylase) signaling. The decrease of LD accumulation was detected in IGFBP3 overexpressing cells treated with PD98059, MAPK (mitogen-activated protein kinase) kinase inhibitor. Additionally, IGFBP3-enhanced cell migration was inhibited by either LD inhibitor (Tracisin C) or PD98059 using the wound healing assay. Our data revealed that IGFBP3 enhanced the cell migration activity through the regulation of LD accumulation by the ERK-AMPK-ACC signal cascade.

[1] S. Warnakulasuriya, “Global epidemiology of oral and oropharyngeal cancer,” Oral Oncol., vol. 45, no. 4–5, pp. 309–316, 2009, doi: 10.1016/j.oraloncology.2008.06.002.
[2] P. M. Speight and P. M. Farthing, “The pathology of oral cancer,” Br. Dent. J., 2018, doi: 10.1038/sj.bdj.2018.926.
[3] V. Ragos et al., “P53 mutations in oral cavity carcinoma,” Journal of B.U.ON. 2018.
[4] C. C. Harris, B. F. Trump, J. A. Welsh, and C. C. Harris, “p53 Mutation and Protein Accumulation during Multistage Human Esophageal Carcinogenesis,” Cancer Res., 1992.
[5] R. Ihsan et al., “Investigation on the role of p53 codon 72 polymorphism and interactions with tobacco, betel quid, and alcohol in susceptibility to cancers in a high-risk population from North East India,” DNA Cell Biol., 2011, doi: 10.1089/dna.2010.1119.
[6] W. Jerjes et al., “Clinicopathological parameters, recurrence, locoregional and distant metastasis in 115 T1-T2 oral squamous cell carcinoma patients,” Head Neck Oncol., 2010, doi: 10.1186/1758-3284-2-9.
[7] Y. A. Wen et al., “Adipocytes activate mitochondrial fatty acid oxidation and autophagy to promote tumor growth in colon cancer,” Cell Death Dis., 2017, doi: 10.1038/cddis.2017.21.
[8] C. Zhang et al., “FABP5 promotes lymph node metastasis in cervical cancer by reprogramming fatty acid metabolism,” Theranostics, 2020, doi: 10.7150/thno.44868.
[9] H. Li, Z. Feng, and M. L. He, “Lipid metabolism alteration contributes to and maintains the properties of cancer stem cells,” Theranostics, 2020, doi: 10.7150/thno.41388.
[10] A. Bleve, B. Durante, A. Sica, and F. M. Consonni, “Lipid metabolism and cancer immunotherapy: Immunosuppressive myeloid cells at the crossroad,” Int. J. Mol. Sci., 2020, doi: 10.3390/ijms21165845.
[11] J. Long et al., “Lipid metabolism and carcinogenesis, cancer development.,” Am. J. Cancer Res., 2018.
[12] A. H. Romano and T. Conway, “Evolution of carbohydrate metabolic pathways,” in Research in Microbiology, 1996, doi: 10.1016/0923-2508(96)83998-2.
[13] H. A. Krebs and W. A. Johnson, “The role of citric acid in intermediate metabolism in animal tissues,” FEBS Lett., 1980, doi: 10.1016/0014-5793(80)80564-3.
[14] Q. Qu, F. Zeng, X. Liu, Q. J. Wang, and F. Deng, “Fatty acid oxidation and carnitine palmitoyltransferase I: Emerging therapeutic targets in cancer,” Cell Death and Disease. 2016, doi: 10.1038/cddis.2016.132.
[15] C. Frezza, “Metabolism and cancer: the future is now,” British Journal of Cancer. 2020, doi: 10.1038/s41416-019-0667-3.
[16] H. D. Grahame, “AMPK: A target for drugs and natural products with effects on both diabetes and cancer,” Diabetes. 2013, doi: 10.2337/db13-0368.
[17] H. Ngo, S. M. Tortorella, K. Ververis, and T. C. Karagiannis, “The Warburg effect: molecular aspects and therapeutic possibilities,” Molecular biology reports. 2015, doi: 10.1007/s11033-014-3764-7.
[18] X. Wang et al., “UDP-glucose accelerates SNAI1 mRNA decay and impairs lung cancer metastasis,” Nature, 2019, doi: 10.1038/s41586-019-1340-y.
[19] H. Pelicano, D. S. Martin, R. H. Xu, and P. Huang, “Glycolysis inhibition for anticancer treatment,” Oncogene. 2006, doi: 10.1038/sj.onc.1209597.
[20] Y. C. Yen et al., “Insulin-like growth factor-independent insulin-like growth factor binding protein 3 promotes cell migration and lymph node metastasis of oral squamous cell carcinoma cells by requirement of integrin β1,” Oncotarget, 2015, doi: 10.18632/oncotarget.5995.
[21] A. Grimberg and P. Cohen, “Role of insulin-like growth factors and their binding proteins in growth control and carcinogenesis,” Journal of Cellular Physiology. 2000, doi: 10.1002/(SICI)1097-4652(200004)183:1<1::AID-JCP1>3.0.CO;2-J.
[22] Y. Higashi, S. Sukhanov, A. Anwar, S. Y. Shai, and P. Delafontaine, “Aging, atherosclerosis, and IGF-1,” Journals of Gerontology - Series A Biological Sciences and Medical Sciences. 2012, doi: 10.1093/gerona/gls102.
[23] S. Zhu, F. Xu, J. Zhang, W. Ruan, and M. Lai, “Insulin-like growth factor binding protein-related protein 1 and cancer,” Clinica Chimica Acta. 2014, doi: 10.1016/j.cca.2014.01.037.
[24] M. D. Lacher, R. J. Pincheira, and A. F. Castro, “Consequences of interrupted Rheb-to-AMPK feedback signaling in tuberous sclerosis complex and cancer,” Small GTPases, 2011, doi: 10.4161/sgtp.2.4.16703.
[25] D. Garcia and R. J. Shaw, “AMPK: Mechanisms of Cellular Energy Sensing and Restoration of Metabolic Balance,” Molecular Cell. 2017, doi: 10.1016/j.molcel.2017.05.032.
[26] Y. Yen et al., “Insulin-like growth factor-independent insulin-like growth factor binding protein 3 promotes cell migration and lymph node metastasis of oral squamous cell carcinoma cells by requirement of integrin β1,” vol. 6, no. 39, 2015.
[27] S. Varma Shrivastav, A. Bhardwaj, K. A. Pathak, and A. Shrivastav, “Insulin-Like Growth Factor Binding Protein-3 (IGFBP-3): Unraveling the Role in Mediating IGF-Independent Effects Within the Cell,” Frontiers in Cell and Developmental Biology. 2020, doi: 10.3389/fcell.2020.00286.
[28] L. Girnita, C. Worrall, S. I. Takahashi, S. Seregard, and A. Girnita, “Something old, something new and something borrowed: Emerging paradigm of insulin-like growth factor type 1 receptor (IGF-1R) signaling regulation,” Cellular and Molecular Life Sciences. 2014, doi: 10.1007/s00018-013-1514-y.
[29] M. M. Chitnis, J. S. P. Yuen, A. S. Protheroe, M. Pollak, and V. M. Macaulay, “The type 1 insulin-like growth factor receptor pathway,” Clinical Cancer Research. 2008, doi: 10.1158/1078-0432.CCR-07-4879.
[30] C. C. Chung et al., “A fluorescence-based thiol quantification assay for ultra-high-throughput screening for inhibitors of coenzyme A production,” Assay Drug Dev. Technol., 2008, doi: 10.1089/adt.2007.105.
[31] P. E. Porporato, S. Dhup, R. K. Dadhich, T. Copetti, and P. Sonveaux, “Anticancer targets in the glycolytic metabolism of tumors: A comprehensive review,” Front. Pharmacol., 2011, doi: 10.3389/fphar.2011.00049.
[32] H.-S. Kim, “Role of insulin-like growth factor binding protein-3 in glucose and lipid metabolism,” Ann. Pediatr. Endocrinol. Metab., 2013, doi: 10.6065/apem.2013.18.1.9.
[33] H. Itabe, T. Yamaguchi, S. Nimura, and N. Sasabe, “Perilipins: a diversity of intracellular lipid droplet proteins,” Lipids in Health and Disease. 2017, doi: 10.1186/s12944-017-0473-y.
[34] S. M. Jeon, “Regulation and function of AMPK in physiology and diseases,” Experimental & molecular medicine, vol. 48, no. 7. p. e245, 2016, doi: 10.1038/emm.2016.81.
[35] E. B. Taylor et al., “Discovery of TBC1D1 as an insulin-, AICAR-, and contraction-stimulated signaling nexus in mouse skeletal muscle,” J. Biol. Chem., 2008, doi: 10.1074/jbc.M708839200.
[36] K. Sakamoto and G. D. Holman, “Emerging role for AS160/TBC1D4 and TBC1D1 in the regulation of GLUT4 traffic,” American Journal of Physiology - Endocrinology and Metabolism. 2008, doi: 10.1152/ajpendo.90331.2008.
[37] E. L. Greer et al., “The energy sensor AMP-activated protein kinase directly regulates the mammalian FOXO3 transcription factor,” J. Biol. Chem., 2007, doi: 10.1074/jbc.M705325200.
[38] X. N. Li et al., “Activation of the AMPK-FOXO3 pathway reduces fatty acid-induced increase in intracellular reactive oxygen species by upregulating thioredoxin,” Diabetes, 2009, doi: 10.2337/db08-1512.
[39] S. H. Wang et al., “Insulin-like growth factor binding protein 3 promotes radiosensitivity of oral squamous cell carcinoma cells via positive feedback on NF-κB/IL-6/ROS signaling,” J. Exp. Clin. Cancer Res., 2021, doi: 10.1186/s13046-021-01898-7.
[40] S. M. Jeon, N. S. Chandel, and N. Hay, “AMPK regulates NADPH homeostasis to promote tumour cell survival during energy stress,” Nature, 2012, doi: 10.1038/nature11066.
[41] Y. Guo, W. Pan, S. Liu, Z. Shen, Y. Xu, and L. Hu, “ERK/MAPK signalling pathway and tumorigenesis (Review),” Exp. Ther. Med., 2020, doi: 10.3892/etm.2020.8454.
[42] S. R. Fox, L. M. Hill, S. Rawsthorne, and M. J. Hills, “Inhibition of the glucose-6-phosphate transporter in oilseed rape (Brassica napus L.) plastids by acyl-CoA thioesters reduces fatty acid synthesis,” Biochem. J., 2000, doi: 10.1042/0264-6021:3520525.
[43] J. Vogt, R. Traynor, and G. P. Sapkota, “The specificities of small molecule inhibitors of the TGFß and BMP pathways,” Cell. Signal., 2011, doi: 10.1016/j.cellsig.2011.06.019.
[44] L. Tangeman, C. N. Wyatt, and T. L. Brown, “Knockdown of AMP-activated protein kinase alpha 1 and alpha 2 catalytic subunits,” J. RNAi Gene Silenc., 2012.
[45] J. J. Volpe and P. R. Vagelos, “Mechanisms and regulation of biosynthesis of saturated fatty acids,” Physiological Reviews. 1976, doi: 10.1152/physrev.1976.56.2.339.
[46] S. G. Straub, H. Yajima, M. Komatsu, T. Aizawa, and G. W. G. Sharp, “The effects of cerulenin, an inhibitor of protein acylation, on the two phases of glucose-stimulated insulin secretion,” in Diabetes, 2002, doi: 10.2337/diabetes.51.2007.s91.
[47] X. Guo et al., “Glycolysis in the control of blood glucose homeostasis,” Acta Pharm. Sin. B, 2012, doi: 10.1016/j.apsb.2012.06.002.