Correlation between Muc1, Il-32 Genes Silencing and Fas Mrna Levels in Breast Tumors

Breast cancer development is associated with changes in expression of genes that involved in regulation of immune responses. Mucin 1 (MUC1) is aberrantly overexpressed in breast tumors. In cancer cells MUC1 gene expression changes, deviations from the normal protein glycosylation and intracellular localization changes is recorded. MUC1 properties changes lead to metabolic reprogramming, new functions appearance and play an important role in the development of tumors. NF-Kβ linking stimulates the release of inflammatory mediators, cytokines such as IL6. MUC1 is associated with the expression of FAS mRNA, which responsible for apoptosis. MUC1 plays an important regulatory role in the transcription of genes associated with tumor invasiveness, metastasis, angiogenesis, proliferation, apoptosis, drug resistant inflammation. The purpose of our study is investigation the relationship of gene expression.

We studied the expression of genes that may influence on inflammation - interleukin 32 (IL32), on cell metabolism - MUC1 and on Fas-dependent apoptosis (Fas). Tumor samples were collected after surgery from 40 patients with breast cancer. Quantitative reverse transcription PCR (qRTPCR) was carried out to analyze mRNA levels of IL32, MUC1 and Fas. The B2M (Beta-2-microglobulin), UBC (Ubiquitin C), HPRT1 (Hypoxanthinephosphoribosyl transferase 1), YWHAZ (Tyrosine 3 monooxygenase activation protein, zeta polypeptide) house-keeping gene were used as endogenous controls. The levels of gene expressions were measured by comparative Ct-method (ΔΔCt).  At first, we assessed stability of house-keeping gene expression in breast tumor samples. Analysis by the BestKeeper computer program shows that B2M is suitable for the normalization of mRNA expression in human breast tumors samples. MUC1 mRNA was detected in 32 (80%) tumor samples, mRNA IL32 – 26 (65%) tumor samples and Fas mRNA in 38 (95%) tumor samples. It has been noted that all MUC1 mRNA-negative samples were IL-32 mRNA-negative which may indicate common mechanisms of gene regulation. Comparison of mRNA levels of MUC1 and IL32 in the breast tumors showed no differences. Importantly, results of our investigation showed a correlation between increased levels of Fas mRNA and gene silencing IL-32 (r = 0.47, p = 0.004) and MUC1 (r = 0.57, p = 0.002) in breast tumors. This data show the correlation between gene expression mediating inflammation, metabolism and apoptosis in breast cancer tumors. We propose that common regulation mechanisms through NFk-B pathway may take part in the described processes.