PIK۳R۱ targeting by miR-۵۵۷۱-۵p induced tumor progression and invasion in breast cancer

Backgrounds: Breast cancer is considered the most widespread malignancy in womenworldwide. Despite a lot of effort for better management of patients, there are still problems fortheir clinical application due to the complexity of the disease, and thus, new biomarkers foraccurate diagnosis would be of the suitable way. MiRNAs are highly conserved small noncodingregulatory RNAs involved in regulating gene expression during different cellularpathways. MiR-۵۵۷۱ was evaluated in a few cancers but there is no evidence of study in breastcancer. PIK۳R۱ gene is a tumor suppressor, inhibited proliferation, invasion, and metastaticproperties of breast cancer cells. PIK۳R۱ was significantly down-regulated in MDA-MB-۲۳۱compared with MCF-۷ cells line, thus possibly contributing to breast cancer metastasis.Therefore, this study aimed to determine the relationship between miR-۵۵۷۱-۵p expression andcorrelation with PIK۳R۱ gene in breast tumor samples.Materials and Methods: We investigate the expression profile of miR-۵۵۷۱-۵p and PIK۳R۱gene, as one of the putative targets of miR-۵۵۷۱-۵p, in ۵۰ paired breast tumors tissue and theiradjacent normal concerning the clinicopathological features of patients using real-time PCR.The correlation of both miR-۵۵۷۱ and PIK۳R۱gene expression with the overall survival of breastcancer patients was also examined by recruiting the Kaplan-Meier Plotter data portal.Results: According to our data, significant up-regulation of miR-۵۵۷۱-۵p and down-regulationof PIK۳R۱ were observed in clinical breast cancer samples compared with normal tissues (p <۰.۰۰۱). The higher expression of miR-۵۵۷۱ was associated with higher grades and poorprognosis (log-rank p = ۱.۷*۱۰-۵), also a significant difference in overall survival was observedbetween patients with lower expression of PIK۳R۱ (log rank p = ۶.۱*۱۰-۱۲).Conclusion: These results suggest that miR-۵۵۷۱ expression profiling might be clinicallyapplicable as a prognostic biomarker in breast cancer. In addition, up-regulation of miR-۵۵۷۱-۵pand down-regulation of PIK۳R۱ is associated with decreased breast cancer patient survival andpoor prognosis.

کلیدواژه ها:

PIK۳R۱ ، breast cancer ، miR-۵۵۷۱ ، overall survive