Differential gene expression profiles of normal human parotid and submandibular glands

Background: Parotid and submandibular glands have different properties including characteristics of the secreted saliva and tumor incidences. The differences in properties of parotid and submandibular glands are not clear from a genetic viewpoint. Objective: To study differential gene expression profiles between normal human parotid and submandibular glands. Materials and methods: Three pairs of normal parotid and submandibular glands were obtained. RNA was extracted from these samples. After reverse transcription, the cDNA was in vitro-transcribed to produce biotin-labeled cRNA. The purified biotin-labeled cRNA samples were hybridized to microarray chips. Results: Among the 54 675 tested transcripts, 47 transcripts were upregulated at least twofold in the parotid gland compared with the submandibular gland, including tumor-associated genes (pleiotrophin, WNT5A, ABCC1) and transport-associated genes (SLCO1A2, SLC13A5, KCNJ15). Ninety-eight transcripts were upregulated at least twofold in the submandibular gland compared with the parotid gland, including the chloride channel CFTR and mucin-associated genes that belong to the starch and sucrose metabolism pathway (GalNAc-T4, GalNAc-T7 and GalNAc-T13). Quantitative real-time reverse transcriptase-polymerase chain reaction (RT-PCR) analysis of nine differentially expressed genes confirmed the microarray results. Conclusion: This study revealed the different gene expression profiles of normal human parotid and submandibular glands, providing a genetic basis for their differing properties.