We found that differential miRNA expression in breast cancer could be variable between Lebanese and Western populations. miR-10b was positively correlated with the ER and PR status and miR-155 could be a noteworthy biomarker for the menopausal state, age at diagnosis, PR and Her2 status.
As a result, the relatively larger (<100 nm) particles precipitated by PEG5k clearly exhibited the greatest amount of epithelial cell adhesion molecule (EpCAM), from both breast cancer (MCF-7) and colon cancer (HCT116) cells, and a larger quantity of microRNA (miRNA) specific to breast cancer cells (miRNA155 for MCF-7) seemed to be contained in the PEG-precipitated particles.
By virtue of these advantages, the PA nanoprobes may provide a powerful platform for in situ detection of miR-155 and thus real-time monitoring of tumorigenesis and drug response in breast cancer.
The relative concentrations of breast cancer-associated miR10b, miR34a, miR141 and miR155 were measured in the blood serum of 89 patients with primary breast cancer (M0, n = 59) and metastatic disease (M1, n = 30), and 29 healthy women by a TaqMan MicroRNA Assay.
The developed biosensor not only was capable to identification of fully matched versus one-base mismatch miRNA-155 sequence, but also it could detect target miRNA-155 in spiked real human serum and extracts from human breast cancer cell-line samples.
Here, we identified 33 miRNAs with similar deregulated expression in both benign and malignant tumors compared with the expression levels of those in normal tissue, including breast cancer-related miRNAs such as let-7, miR-21 and miR-155.
Furthermore, the relative expression of miR-21, miR-126, miR-155, miR-199a and miR-335 was closely associated with clinicopathologic features of breast cancer (P < 0.05), such as histological tumor grades and sex hormone receptor expression.
In this work we show that MGP is significantly repressed by miR-155 in breast cancer MCF-7 cells, and concomitantly there is a stimulation of cell proliferation and cell invasiveness.
Certain well-known oncogenes (MYC and HGF), cytokines (CSF2, IFNG and IL5) and microRNAs (miR-21, miR-155-5p and let-7) may participate in the ILF2 expression network in breast cancer.
In conclusion, detection of the miRNA-17-5p, miR-155 and miRNA-222 expression levels in serum samples is significant promising molecular markers for early breast cancer diagnosis.
We observed that the oncogenic miR-155 level was down-regulated in the antitumor CTL against breast cancer, and it may be used as the effective treatment to eliminate the malignant cells in the breast cancer patients.
In summary, we have demonstrated that the transfer of miR-155 from exosomes acts as an oncogenic signal reprograming systemic energy metabolism and leading to cancer-associated cachexia in breast cancer.
Using quantitative reverse transcription polymerase chain reaction (RT-qPCR), we demonstrated that serum miR-155 had significant increased levels in breast cancer patients (n = 103) compared with healthy subjects (n = 55) (p<0.001), which had a mean fold change of 2.94.
In the present study, we have evaluated the expression of 6 circulating miRNAs, (miR-16, miR-21, miR-23α, miR-146α, miR-155 and miR-181α), in operable BCa patients, with non-metastatic, invasive ductal carcinoma, not receiving neoadjuvant chemotherapy.
The results of this pilot study indicate a possible involvement of miR-155 in surgery-induced angiogenesis and potential prognostic significance of high postoperative levels of circulating miR-195 in patients with breast cancer.