The Expression Of AQP3 In Breast Cancer And The Transcriptional Regulation By RUNX2

Breast cancer has become the most common malignant tumor among female in the world,well understanding of the mechanisms of invasion,cell proliferation and migration is very important for investigating possible anti-tumor therapies.Aquaporins(AQPs)are a classes of small complete membrane proteins,widely distributed in organisms.There are thirteen members(AQP0-12),which have been identified in mammals.AQP3,a member of the aquaglyceroporins subgroup,which is widely distributed in the human renal collecting duct,epidermis,conjunctiva and mammary glands.According to reports,AQP3 could facilitate cell migration via transportation of water and glycerol for lamellipodia formation,what’s more,it could lead to cellular proliferation by maintaining a high level of cellular glycerol used for the generation of ATP and lipid biosynthesis.Animal experiments show that dysfunction of urinary concentration,the skin wound healing and the digestive tract mucosa repair delay.On the contrary,enhancement of AQP3 function,via upregulating AQP3 expression,may promote the formation and progress of tumor.Recent studies shows that AQP3 expression was related to tumor occurrence and development such as cutaneous squamous cell carcinoma,lung adenocarcinoma,gastric adenocarcinoma.Runx2 is a nuclear transcription factor,the expression of these proteins is closely related to the expression of tumor metastasis.In breast cancer,prostate cancer and other malignant tumors,the expression of Runx2 is significantly increased,and its high expression and cell transformation and tumor progression is closely related.The function of Runx2 is involved in several signal passageway,including P13K/AKT-MAPK/ERK and TGF-β-Smads pathway,which promotes the metastasis of malignant tumors.In our previous study,we found FGF-2-induced migration in MDA-MB-231 cell lines and increased AQP3 and Runx2 expression.Lentiviral sh RNA silencing Runx2 decreased AQP3 expression.We also found FGF-2-induced AQP3 expression via PI3 K and ERK pathway.However,the expression of AQP3 and its clinical significance is not very clear in breast cancer.Runx2,as a transcription factor,we do not known whether it regulates the transcription of AQP3 gene.In this article,we will study the characteristics ofAQP3 expression in breast cancer tissues and the transcriptional regulation of Runx2 on AQP3 gene,combining with previous studies,to clarify the role of AQP3 expression regulated by Runx2 in FGF-2 induced migration.IHC assay were used to evaluate the correlation between expression of AQP3 and clinic-pathology of breast cancer patients.and we found the expression of AQP3 was negatively correlated with the prognosis of breast cancer patients.Ch IP assay was performed to confirm the binding of Runx2 to AQP3 promoter in MDA-MB-231 cells,and the DNA fragment was detected and identified by PCR technique.PGL3-Basic-AQP3-Promoter Luciferase Report Gene was constructed in order to detect whether Runx2 directly upregulates AQP3 in the promoter of the AQP3 gene or not.The recombinant plasmid was transfected into MDA-MB-231 cells,and luciferase activity was detected.Disruption of Runx2 binding site led to significant decrease of AQP3 promoter activity in MDA-MB-231 cells,while upregulated the expression of Runx2 led to significant increase of AQP3 promoter activity.In conclusion,we found AQP3 were related to the prognosis of breast cancer patients.In vitro experiments,Ch IP assay confirmed that Runx2 binding AQP3 promoter,and luciferase assay confirmed that transcription factor Runx2 positively regulates the activity of AQP3 promoter.Therefore,AQP3 upstream regulatory gene Runx2 maybe a target for tumor therapy.