New Diagnosis of Salivary Gland tumors with RT-PCR and differentiation of Salivary Gland Stem Cell into Acinic Cell

1998 Fiscal Year Final Research Report Summary

• Project/Area Number: 09671919
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: 病態科学系歯学(含放射線系歯学)
• Research Institution: Osaka University
• Principal Investigator: OKURA Masaya Hospital Attached to Faculty of Dentistry, Osaka University.lecturer, 歯学部・附属病院, 講師 (10281130)
• Project Period (FY): 1997 – 1998
• Keywords: salivary gland / differentiation / cell biology / salivary gland tumor / salivary alpha-amylase

Research Abstract

In our 1997 study, human salivary gland tissues, cultured salivary gland cells and salivary gland neoplasms have expressedsalivary alpha-amylase (AMY) mRNA and alpha-smooth-muscle-actin (SMA) mRNA with reverse transcriptional polymerase chain reaction (RT-PCR).The expresssions show a tendency to reduce in proportion to malignant transformation.MUC7 specific bands were detected in human salivary gland tissues of normal salivary gland and salivary gland neoplasms, but not detected in cultured cells.Then the different MUC7 primers were generated.With using these primers, cultured cells of both normal cells and pleomorphic adenoma cells expressed MUC7 mRNA, while adenocarcinoma and adenoid cystic carcinoma cells did not.The expression level of AMY mRNA, SMA mRNA and MUC7 mRNA has reduced in proportion to their malignancy.Then we submitted these study to a certain journal.However, the number of malignant salivary gland tissues we studied were small, and our RT-PCR method was pointed out to have a limit for competitive study.Unfortunately, we do have only a small amount of RNAs of salivaly gland neoplasm tissues, because the neoplasms have rare nature.we have maken the new primers and attempted the competitive reverse transcriptional polymerase chain reaction by using double primers and RNA-protection-assay.Because it was difficult to set the suitable anneling temperature and to avoid generating primer dimer, we did not get the reproducible results, but the trend of our results was similar to our previous one.We do not have the reproducible results yet, and the amount of RNAs of salivaly gland neoplasm tissues is limited to use.Now we are studying in expressions of only cultured cells.As regards with the differentiation of salivary gland stem cell into acinic cell, spindle-shaped cells, which were initially thought to be myoepthelial cell, had the characteristics of acinar cell as a result of electron microscopic study and expression analysis of cytoskeleton.For acinar differentiation of stem cells, it needs the following conditions : medium contains a fetal bovin serum, cell population is enough high in some degree and a time more than one week needs for acinar differentiation, and there might be an intermediated stage between mature acinic cells and stem cells.The necessary time for differentiation might suggest that the differetiations not simple one signal transduction, but the complicated signals have induced the differentiation.We are now studying to make sure what is an important signal.