Digvijay Singh1, Rohit K Deshmukh2, Amitava Das3. 1. Department of Applied Biology, Council of Scientific and Industrial Research-Indian Institute of Chemical Technology (CSIR-IICT), Uppal Road, Tarnaka, Hyderabad 500 007, TS, India; Academy of Science and Innovative Research (AcSIR), Ghaziabad, UP 201 002, India. 2. Department of Applied Biology, Council of Scientific and Industrial Research-Indian Institute of Chemical Technology (CSIR-IICT), Uppal Road, Tarnaka, Hyderabad 500 007, TS, India. 3. Department of Applied Biology, Council of Scientific and Industrial Research-Indian Institute of Chemical Technology (CSIR-IICT), Uppal Road, Tarnaka, Hyderabad 500 007, TS, India; Academy of Science and Innovative Research (AcSIR), Ghaziabad, UP 201 002, India. Electronic address: amitavadas@iict.res.in.
Abstract
BACKGROUND: Triple-negative breast cancer (TNBC) tumors are composed of a heterogeneous population containing both cancer cells and cancer stem cells (CSCs). These CSCs are generated through an epithelial-to-mesenchymal transition (EMT), thus making it pertinent to identify the unique EMT-molecular targets that regulate this phenomenon. METHODS AND RESULTS: In the present study, we performed in silico analysis of microarray data from luminal, Her2+, and TNBC cell lines and identified 15 relatively unexplored EMT-related differentially expressed genes (DEGs) along with the markedly high expression of EMT-transcription factor (EMT-TF), SNAI1. Interestingly, stable overexpression of SNAI1 in MCF-7 induced the expression of DEGs along with increased migration, invasion, and in vitro tumorigenesis that was comparable to TNBCs. Next, stable SNAI1 overexpression led to increased expression of DEGs that was reverted with SNAI1 silencing in both breast cancer cells and CSCs sorted from various TNBC cell lines. Higher fold enrichment of SNAI1 on E-boxes in the promoter regions suggested a positive regulation of ALCAM, MMP2, MMP13, MMP14, VCAN, ANKRD1, KRT16, CTGF, TGFRIIβ, PROCR negative regulation of CDH1, DSP and DSC3B by SNAI1 leading to EMT. Furthermore, SNAI1-mediated increased migration, invasion, and tumorigenesis in these sorted cells led to the activation of signaling mediators, ERK1/2, STAT3, Src, and FAK. Finally, the SNAI1-mediated activation of breast CSC phenotypes was perturbed by inhibition of downstream target, MMPs using Ilomastat. CONCLUSION: Thus, the molecular investigation for the gene regulatory framework in the present study identified MMPs, a downstream effector in the SNAI1-mediated EMT regulation.
BACKGROUND: Triple-negative breast cancer (TNBC) tumors are composed of a heterogeneous population containing both cancer cells and cancer stem cells (CSCs). These CSCs are generated through an epithelial-to-mesenchymal transition (EMT), thus making it pertinent to identify the unique EMT-molecular targets that regulate this phenomenon. METHODS AND RESULTS: In the present study, we performed in silico analysis of microarray data from luminal, Her2+, and TNBC cell lines and identified 15 relatively unexplored EMT-related differentially expressed genes (DEGs) along with the markedly high expression of EMT-transcription factor (EMT-TF), SNAI1. Interestingly, stable overexpression of SNAI1 in MCF-7 induced the expression of DEGs along with increased migration, invasion, and in vitro tumorigenesis that was comparable to TNBCs. Next, stable SNAI1 overexpression led to increased expression of DEGs that was reverted with SNAI1 silencing in both breast cancer cells and CSCs sorted from various TNBC cell lines. Higher fold enrichment of SNAI1 on E-boxes in the promoter regions suggested a positive regulation of ALCAM, MMP2, MMP13, MMP14, VCAN, ANKRD1, KRT16, CTGF, TGFRIIβ, PROCR negative regulation of CDH1, DSP and DSC3B by SNAI1 leading to EMT. Furthermore, SNAI1-mediated increased migration, invasion, and tumorigenesis in these sorted cells led to the activation of signaling mediators, ERK1/2, STAT3, Src, and FAK. Finally, the SNAI1-mediated activation of breast CSC phenotypes was perturbed by inhibition of downstream target, MMPs using Ilomastat. CONCLUSION: Thus, the molecular investigation for the gene regulatory framework in the present study identified MMPs, a downstream effector in the SNAI1-mediated EMT regulation.