We analyzed the expression of several microRNAs (miRs) implicated in breast cancer (BC) pathogenesis (miR-21, miR-10b, miR17-5p, mir-31, miR-155, miR-200c, miR-18a, miR-205, and miR-27a) in 80 breast carcinomas obtained from patients with bilateral BC (biBC) and 40 cases of unilateral BC (uBC).
To explore the relevance of miRNA polymorphisms and female physiological characteristics to breast cancer risk, SNPs located within hsa-miR-605 (rs2043556), hsa-miR-149 (rs2292832), hsa-miR-27a (rs895819), hsa-miR-196a-2 (rs11614913) and hsa-miR-618 (rs2682818) were selected, and their associations with breast cancer risk were analysed.
We observed that the expression levels of miR-23a, miR-24-2 and miR-27a were significantly higher in breast cancer with lymph node metastasis, compared with that from patients without lymph node metastasis or normal tissue.
This meta-analysis suggests that the pre-miR-27ars895819 polymorphism may contribute to the susceptibilities of some specific-type of cancers, including breast cancer, renal cell cancer, nasopharyngeal cancer and digestive tract cancers, as well as the susceptibilities of cancers in Caucasians to some extent.
The rs9383935 risk allele A showed decreased activity of reporter gene in both the MCF-7 and BT-474 breast cancer cell lines, which might be due to an altered binding capacity of miR-27a to the 3' untranslated region (3' UTR) sequence of CCDC170.
Compared with the ancestral T allele in miR-196a2 rs11614913, the variant C allele was consistently associated with an increased risk of breast cancer (odds ratio = 2.20, 95% confidence interval = 1.19-4.09, P < 0.01) and clinical pathological type (P < 0.01). miR-27ars895819 A>G and miR-499 rs3746444 A>G were not associated with breast cancer risk.
When stratified by ethnicity, the effects remained in Asians. rs895819 (miR-27a) was associated with BC risk in the overall population based on the allele contrast genetic model (OR = 0.91, 95%CI = 0.85-0.98, P=0.02); heterozygote comparison (OR = 0.89, 95 %CI = 0.80-0.99, P=0.03) and the dominant model (OR = 0.89, 95% CI = 0.80-0.98, P=0.02).
Our findings support the following conclusions: a) rs6505162:C > A in pre-miR-423 increases risk of familial BC in families with a strong history of BC; b) the C/A genotype at rs2682818:C > A (pre-miR-618) increases BC risk in non-familial early-onset BC; and c) the G/G genotype at rs895819:A > G (miR-27a) reduces BC risk in families with a moderate history of BC.
Therefore, the present study aimed to explain this phenomenon in regards to the relationship between microRNAs (miRNAs) and their target genes and to predict how AMPKα2 may be a downstream target gene of miR-27a, thus exploring the new mechanism of metformin in the treatment of breast cancer regarding miRNAs.
This study aims to explore the effects of microRNA-27a (miR-27a) targeting of SFRP1 on the proliferation, migration and invasion of breast cancer (BC) cells through the regulation of Wnt/β-catenin signaling pathway.
Altogether, the results of the present study indicated the important function of miR‑27a in regulating the metastasis of breast cancer in a FBXW7‑dependent manner, and provide evidence for the potential application of miR‑27a in breast cancer therapy.