1. Key Laboratory of Translational Radiation Oncology, Hunan Province, Hunan Cancer Hospital and The Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, 283 Tongzipo Road, Changsha 410013, Hunan, China;
2. The Key Laboratory of Carcinogenesis of the Chinese Ministry of Health and The Key Laboratory of Carcinogenesis and Cancer Invasion of the Chinese Ministry of Education, Cancer Research Institute, Central South University, 110 Xiangya Road, Changsha 410078, Hunan, China;
3. Hunan Key Laboratory of Nonresolving Inflammation and Cancer, Disease Genome Research Center, The Third Xiangya Hospital, Central South University, 138 Tongzipo Road, Changsha 410013, Hunan, China.
# These authors contributed equally to this work.
Objective: This study aims to investigate the roles and mechanisms of long palate, lung and nasal epithelium clone 1 (LPLUNC1) in nasopharyngeal carcinoma (NPC).
Methods: The two-dimensional fluorescence difference gel electrophoresis (2-D DIGE) and matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF-TOF-MS/MS) was applied to identify differentially expressed proteins after over-expressing LPLUNC1 in NPC cells. The qRT-PCR and Western Blot were used to further validate differentially expression of Hypoxia up-regulated 1 (HYOU1). We also applied immunohistochemistry (IHC) to validate the expression of HYOU1 protein in NPC tissues.
Results: Totally 44 differentially expressed proteins were identified, among which 19 proteins were up-regulated and 25 proteins were down-regulated. Function annotation indicated that these proteins were involved in molecular chaperone, cytoskeleton, metabolism and signal transduction. It was shown that the expression of HYOU1 both at mRNA level and protein level was up-regulated significantly in NPC tissues, and HYOU1 protein expression was positively correlated with clinical staging and metastasis of NPC. Kaplan-Meier survival curves showed that high expression of HYOU1 protein in NPC patients had shorter progression-free survival (PFS) and overall survival (OS). COX multivariate regression analysis further indicated that over-expressed HYOU1 was one of the predictors for poor prognosis in NPC patients.
Conclusion: Through regulating proteins in different pathways, LPLUNC1 may inhibit the growth of NPC through participating in cell metabolism, proliferation, transcription and signaling transduction. HYOU1 can be regarded as potential molecular biomarker for progression and prognosis of NPC.
Keywords: Nasopharyngeal carcinoma, LPLUNC1, Proteomics, 2-D DIGE, MALDI-TOF-TOF-MS/MS, HYOU1.