Instituto Nacional de CâncerBreast cancer (BC) is a heterogeneous disease composed of multiple subtypes with different molecular characteristics and clinical outcomes. In Brazil, this neoplasia is the first cause of cancer death in women due to diagnosis in advanced stages and occurrence of metastasis. The metastatic process is related to expression of epithelial-to-mesenchymal transition transcription factors (EMT-TFs) SNAIL, SLUG, SIP1 and TWIST1. We recently described the role of NF-κB as a transcriptional regulator of TWIST1, SLUG and SIP1 in aggressive BC cells HCC-1954 (Her2 positive) and MDA-MB-231 (Triple-negative, TNBC). Here, we investigated the expression of mRNA levels for NF-κB and the EMT-TFs through RT-qPCR in breast tumor samples. We observed a clear positive correlation between NF-κB and Twist (r = 0.923; P < 0.0001), Slug (r = 0.786; P = 0.007) and Sip1 expression (r = 0.940; P < 0.0001), confirming that NF-κB activates these EMT-TFs. A comparison among the breast cancer subtypes revealed that TNBC group expressed significantly more NF-κB, Slug and Sip1. We also observed more expression of Twist1 in HER2 group than other subtypes. The role of Twist1 during the evolution of different BC subtypes remains unclear. We inhibited the expression of Twist1 in HCC-1954 cells (Her2 positive), using the specific interfering RNA (shTwist), that was confirmed in relation to negative silencing control. A large-scale microarray analysis of the effect of this silencing showed profound molecular alterations: 141 genes showed increased or decreased expression. Metacore analysis software grouped these genes according to molecular function, revealing numerous correlations between Twist1 and important biological processes and signaling pathways such as Blood Coagulation, TGF-b/SMADs signaling, Interleukin-17, and e.g. Our findings may contribute to a greater understanding of the metastatic process of this neoplasia and highlight NF-κB and Twist1 as potential target for breast cancer treatment. breast cancer, Epithelial-Mesenchymal Transition, Metastasis, NF-kappaB, Twist1
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REGULATORY NETWORK OF THE METASTATIC PROCESS IN BREAST CANCER
Pires, B.R.B. (Instituto Nacional de Câncer ), Ferreira, G. M. (Instituto Nacional de Câncer ), Binato, R. (Instituto Nacional de Câncer ), Abdelhay, E. (Instituto Nacional de Câncer )
Instituto Nacional de CâncerBreast cancer (BC) is a heterogeneous disease composed of multiple subtypes with different molecular characteristics and clinical outcomes. In Brazil, this neoplasia is the first cause of cancer death in women due to diagnosis in advanced stages and occurrence of metastasis. The metastatic process is related to expression of epithelial-to-mesenchymal transition transcription factors (EMT-TFs) SNAIL, SLUG, SIP1 and TWIST1. We recently described the role of NF-κB as a transcriptional regulator of TWIST1, SLUG and SIP1 in aggressive BC cells HCC-1954 (Her2 positive) and MDA-MB-231 (Triple-negative, TNBC). Here, we investigated the expression of mRNA levels for NF-κB and the EMT-TFs through RT-qPCR in breast tumor samples. We observed a clear positive correlation between NF-κB and Twist (r = 0.923; P < 0.0001), Slug (r = 0.786; P = 0.007) and Sip1 expression (r = 0.940; P < 0.0001), confirming that NF-κB activates these EMT-TFs. A comparison among the breast cancer subtypes revealed that TNBC group expressed significantly more NF-κB, Slug and Sip1. We also observed more expression of Twist1 in HER2 group than other subtypes. The role of Twist1 during the evolution of different BC subtypes remains unclear. We inhibited the expression of Twist1 in HCC-1954 cells (Her2 positive), using the specific interfering RNA (shTwist), that was confirmed in relation to negative silencing control. A large-scale microarray analysis of the effect of this silencing showed profound molecular alterations: 141 genes showed increased or decreased expression. Metacore analysis software grouped these genes according to molecular function, revealing numerous correlations between Twist1 and important biological processes and signaling pathways such as Blood Coagulation, TGF-b/SMADs signaling, Interleukin-17, and e.g. Our findings may contribute to a greater understanding of the metastatic process of this neoplasia and highlight NF-κB and Twist1 as potential target for breast cancer treatment. breast cancer, Epithelial-Mesenchymal Transition, Metastasis, NF-kappaB, Twist1