Suppression of OSCC malignancy by oral glands derived-PIP identified by iTRAQ combined with 2D LC-MS/MS.

Qibo Wang,Xiao Liang,Shaoming Li,Keqian Zhi,Xinyu Quan,Yuting Wang,Yuan Zhi,Ling Gao,Wenhao Ren,Xiaoming Xing,Zhichao Dou,Chunmiao Jiang

doi:10.1002/jcp.28180

Abstract

Oral squamous cell carcinoma (OSCC) is the most common malignancy in head and neck cancer and a global cause of cancer‐related death. Due to the poor survival rates associated with OSCC, there is a growing need to develop novel technologies and predictive biomarkers to improve disease diagnosis. The identification of new cellular targets in OSCC tumors will benefit such developments. In this study, isobaric tags for relative and absolute quantitation (iTRAQ)‐based proteomics analysis combined with 2‐dimensional liquid chromatography and tandem mass spectrometry (2D LC‐MS/MS) were used to identify differentially expressed proteins (DEPs) between tumor and normal tissues. Of the DEPs detected, the most significantly downregulated protein in OSCC tissue was prolactin‐inducible protein (PIP). Clonogenic and 3‐(4,5‐dimethyl‐2‐thiazolyl)‐2,5‐diphenyl‐2H‐tetrazolium bromide (MTT) experiments showed that the proliferation capacity of OSCC cells overexpressing PIP decreased due to cell cycle arrest at the G0/G1 checkpoint. Wound‐healing and transwell assay further showed that PIP overexpression also reduced the migration and invasion of OSCC cells. Immunohistochemistry (IHC) was used to analyze the expression in OSCC, indicating that PIP may be secreted by glandular cells and have an inhibitory effect on OSCC cells to produce. In western blot analysis, silencing studies confirmed that PIP mediates these effects through the AKT/mitogen‐activated protein kinase (MAPK) signaling axis in OSCC cells. Taken together, this study reveals PIP as a key mediator of OSCC cell growth, migration, and invasion through its effect on AKT/MAPK signaling.

Highlights

Head and neck cancer is the sixth most common human malignancy worldwide and it is estimated that more than 90% of those are oral squamous cell carcinoma (OSCC; Choi & Myers, 2008; Markopoulos, 2012)
ITRAQ labeling was coupled with 2D LC‐MS/MS to detect the differentially expressed proteins (DEPs) between Oral squamous cell carcinoma (OSCC) and normal oral tissue (Xiao et al, 2015)
We found that prolactin‐inducible protein (PIP) could regulate the proliferation, migration, and invasion of OSCC through AKT/mitogen‐activated protein kinase (MAPK) signaling

Summary

| INTRODUCTION

Head and neck cancer is the sixth most common human malignancy worldwide and it is estimated that more than 90% of those are oral. The majority of patients with OSCC are diagnosed during the late stages of the disease. In this regard, new biomarkers are urgently required for early OSCC detection. Wang et al, 2017; Xiao et al, 2015; Yang, Chen, Chan, Li, & Zhang, 2017; Zhang et al, 2017) This technique permits the identification of differentially expressed proteins (DEPs) between tumor and normal tissues (Li et al, 2017). ITRAQ labeling was coupled with 2D LC‐MS/MS to detect the DEPs between OSCC and normal oral tissue (Xiao et al, 2015). We predict that PIP is secreted by acinar cells into the stroma to act on OSCC cells

| MATERIALS AND METHODS

| RESULTS

Findings

| DISCUSSION