Silencing of Astrocyte Elevated Gene-1 (AEG-1) inhibits the proliferative and invasive potential through interaction with Exostosin-1 (EXT-1) in primary and metastatic colon cancer cells

Colon cancer is the third major cause of cancer deaths, accounting for about 8% in terms of mortality globally. The present study aims to explore the effect of silencing Astrocyte Elevated Gene-1 (AEG-1), a metastasis mediating factor, and how it interacts with Exostosin-1 (EXT-1) protein to inhibit the proliferative and invasive potential in colon cancer cells. Forward siRNA transfection was performed using AEG-1 siRNA in SW480 and SW620 colon cancer cell lines, and the expression levels of mRNA and protein were analyzed by Real-time PCR and Immunofluorescence. A simple bioinformatics approach was carried out to identify the possible interactions between AEG-1 and EXT-1 using Easy Networks and Pathway Commons Database. Cell survival and clonal efficiency were determined using Cell Counting Kit-8 assay and clonogenic assay, apoptosis using flow cytometry analysis, migration and invasion using scratch and Transwell assays, respectively. Forward siRNA transfection significantly suppressed the expression of AEG-1 in mRNA and protein levels on SW480 and SW620 colon cancer cells. From our results, we found that EXT-1 mRNA and protein level was significantly upregulated in AEG-1 siRNA transfected cells. Moreover, treatment with AEG-1 siRNA inhibited the proliferation, clonogenic ability, migration, and invasion and also induced apoptosis. Through the bioinformatic approach, our data analyses pointed towards the crosstalk between AEG-1 and EXT-1 mediated through Patched-1 (PTCH-1) protein. Our current results demonstrated that silencing AEG-1 can restrain cell proliferation, migration, and invasion, ultimately leading to apoptosis. In AEG-1 siRNA transfected cells, PTCH-1 activity might be modulated by several genes and, in turn, affects the EXT-1 activity. Collectively, these observations not only provide insight into the interplay between AEG-1 and EXT-1 but also suggest that AEG-1 may represent a possible candidate therapeutic target through interaction with EXT-1 in colon cancer.