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Ling Wang, Zhengfeng Wang, Zhaoxia Huang, Xiaohui Hu, Shuai Li, Zachary G Woodward, Quan Dong Nguyen, David W Li, lens; The Small Heat Shock Protein AlphaA-Crystallin Acts as An Tumor Suppressor in Pancreas. Invest. Ophthalmol. Vis. Sci. 2015;56(7 ):5876.
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© ARVO (1962-2015); The Authors (2016-present)
aA-crystallin is a member of the small heat-shock protein family (sHSPs) with multiple functions. Small HSPs act as molecular chaperones, and participate in signaling transduction, cell proliferation, cell metabolism, cell survival, apoptosis, senescence, exocytosis and endocytosis. Studies from numerous laboratories including ours have revealed that sHSPs also actively regulate tumorigenesis. As a major lens structural protein, aA-crystallin is also expressed in non-lenticular tissues including retina, spleen and thymus. Our recent study demonstrated that aA-crystallin is significantly expressed in mouse pancreas. Regarding its function in pancreas, it remains to be investigated.
RT-PCR, immunocytochemistry and Western blot analysis were used for detection of gene expression. Overexpression and knockdown were used to enrich or attenuate gene expression. Colony assays were used to detect the cell transformation.
Analysis of aA-crystallin in the tissue samples from normal human pancreas and dozens of cases of pancreatic carcinoma reveals significant difference. aA-crystallin is downregulated over 10-fold in the pancreatic carcinoma of various types than that in normal pancreas, indicating that aA-crystallin has tumor suppression functions. Moreover, aA-crystallin negatively regulates cell migration as shown in the cell wound healing assay. In addition, expression of aA-crystallin is significantly lower in majority of cancer cell lines compared with the hTERT-transfected normal pancreatic cells (HPNE cells). When aA-crystallin is knocked down in the pancreatic cells expressing moderate aA-crystallin, the transformation and cell migration abilities are clearly enhanced. In contrast, when aA-crystallin is expressed in those pancreatic cancer cells lacking endogenous aA-crystallin, the transformation and cell migration abilities of the transgenic cells became significantly attenuated.
These results provide evidence to support the conclusion that aA-crystallin negatively regulates pancreatic carcinogenesis.
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