Integration of metabolomics, transcriptomics, and microRNA expression profiling reveals a miR-143-HK2-glucose network underlying zinc-deficiency-associated esophageal neoplasia.

Louise Y Fong,Oliver Fiehn,Johannes Fahrmann,Karl J Smalley,Cristian Taccioli,Carlo M Croce,Ruiyan Jing,Dinesh K Barupal,John L Farber,Hansjuerg Alder

doi:10.18632/oncotarget.18434

Abstract

Esophageal squamous cell carcinoma (ESCC) in humans is a deadly disease associated with dietary zinc (Zn)-deficiency. In the rat esophagus, Zn-deficiency induces cell proliferation, alters mRNA and microRNA gene expression, and promotes ESCC. We investigated whether Zn-deficiency alters cell metabolism by evaluating metabolomic profiles of esophageal epithelia from Zn-deficient and replenished rats vs sufficient rats, using untargeted gas chromatography time-of-flight mass spectrometry (n = 8/group). The Zn-deficient proliferative esophagus exhibits a distinct metabolic profile with glucose down 153-fold and lactic acid up 1.7-fold (P < 0.0001), indicating aerobic glycolysis (the “Warburg effect”), a hallmark of cancer cells. Zn-replenishment rapidly increases glucose content, restores deregulated metabolites to control levels, and reverses the hyperplastic phenotype. Integration of metabolomics and our reported transcriptomic data for this tissue unveils a link between glucose down-regulation and overexpression of HK2, an enzyme that catalyzes the first step of glycolysis and is overexpressed in cancer cells. Searching our published microRNA profile, we find that the tumor-suppressor miR-143, a negative regulator of HK2, is down-regulated in Zn-deficient esophagus. Using in situ hybridization and immunohistochemical analysis, the inverse correlation between miR-143 down-regulation and HK2 overexpression is documented in hyperplastic Zn-deficient esophagus, archived ESCC-bearing Zn-deficient esophagus, and human ESCC tissues. Thus, to sustain uncontrolled cell proliferation, Zn-deficiency reprograms glucose metabolism by modulating expression of miR-143 and its target HK2. Our work provides new insight into critical roles of Zn in ESCC development and prevention.

Highlights

Cancer mortality rates have declined worldwide since the mid 1980s, esophageal squamous cell carcinoma (ESCC), the predominant esophageal cancer subtype, has a 5-year survival of only 10% [1]
To understand the distribution and localization of miR-143 in esophageal neoplasia in relation to localization of its target HK2 protein and the level of cell proliferation, we performed in situ hybridization (ISH) and immunohistochemical staining (IHC) on near serial sections of rat esophageal tissues (n = 10 rats/group), as well as in the archived human ESCC tissues for which we previously reported overexpression of miR-31, -21, -223 [27, 28]
Glucose downregulation (153-fold, P < 0.001) was accompanied by up-regulation of lactic acid (1.7-fold, P < 0.001), a result indicating a high rate of aerobic glycolysis, a common feature of cancer cell metabolism

Summary

Introduction

Cancer mortality rates have declined worldwide since the mid 1980s, esophageal squamous cell carcinoma (ESCC), the predominant esophageal cancer subtype, has a 5-year survival of only 10% [1]. Clarification of the mechanisms underlying the pathogenesis of ESCC and development of new prevention and therapeutic strategies are critically needed. Zinc (Zn)-deficiency (ZD) is recognized as a major worldwide public health problem [2,3,4,5,6], affecting ~31% of the global population with higher rates in developing countries [5]. Abnet et al [11] demonstrated that tissue Zn concentration is inversely associated with the subsequent risk of developing ESCC. Because Zn is required for the activity of hundreds of enzymes, for proper immune function, and for the conformation of > 2000 transcription factors that control cell proliferation, apoptosis, and signaling pathways [12, 13], ZD predisposes to disease by adversely affecting many processes

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Conclusion