The NF‐κB target genes ICAM‐1 and VCAM‐1 are differentially regulated during spontaneous differentiation of Caco‐2 cells

Abstract

Intestinal epithelial differentiation entails the formation of highly specialized cells with specific absorptive, secretory, digestive and immune functions. Cell–cell and cell–microenvironment interactions appear to be crucial in determining the outcome of the differentiation process. Using the Caco‐2 cell line, which undergoes spontaneous re‐differentiation when grown past confluency, we observed a loss of VCAM‐1 (vascular cell adhesion molecule 1) mRNA expression, while ICAM‐1 (intercellular cell adhesion molecule 1) mRNA expression was seen to increase over the course of differentiation. Protein kinase Cθ (PKCθ) acted downstream of protein kinase Cα (PKCα) to inactivate inhibitor of κB (IκB) and activate nuclear factor κB (NF‐κB) in undifferentiated cells, and this pathway was inhibited in the differentiated cells. The increase in ICAM‐1 mRNA expression in the differentiated cells was due to increased promoter recruitment of C/EBPβ, which transcriptionally up‐regulated ICAM‐1 mRNA. However, protein expression of ICAM‐1 was found to decrease over the course of differentiation due to degradation in the proteasome and lysosome. Immunohistochemistry using tumor samples from colon cancer patients indicated that non‐transformed matched normal cells (well‐differentiatied) showed no ICAM‐1 expression, but the poorly differentiated tumor cells showed higher expression. Functionally, a decrease in adhesion to human umbilical vein endothelial cells was observed in the differentiated Caco‐2 cells. Thus, regulation of ICAM‐1 and VCAM‐1, although both NF‐κB target genes, appears to be different over the course of epithelial differentiation in Caco‐2 cells.

Anti-invasion Effect of Crebanine and <i>O</i>-Methylbulbocapnine from <i>Stephania venosa</i> <i>via</i> Down-Regulated Matrix Metalloproteinases and Urokinase Plasminogen Activator

“…NF-κB activation involves its release from IκBα and the subsequent translocation from cytoplasm to the nucleus, where it binds to cognate sequences in the promoter region of many targeted genes, including VEGF, uPA, MMP-9, MT1-MMP, ICAM-1 and COX-2. [33][34][35] Therefore, NF-κB DNA binding activity and translocation from cytoplasm to nucleus are hallmark of its activation. In the present study, we demonstrated that CN and OMBC reduced NF-κB DNA binding activity.…”

Epigenetic Mechanisms Underlying the Dynamic Expression of Cancer-Testis Genes, PAGE2, -2B and SPANX-B, during Mesenchymal-to-Epithelial Transition

“…Cells grown in parallel cultures were used to determine phenotypic changes at days 0, 5, 10, 20 and 30, post-confluence. Additional measures of differentiation for cells used in this study have been reported elsewhere [15]. To induce dedifferentiation, cells at the 20th day of differentiation were detached and replated at about 50% confluence and RNA and protein were harvested 5 days following replating.…”

Snail1-dependent transcriptional repression of Cezanne2 in hepatocellular carcinoma

“…4,5 Several important targets of NF-kB-mediated transcription, such as intercellular adhesion molecule 1 (ICAM1), were reported to associate with and be highly expressed in HCC progression. 6,7 Although it was not associated with effects on cell survival, ICAM1 was linked to mediate cell adhesion and extravagation in both tumor progression and metastasis. 6,7 In addition, NF-kB was a key transcription factor in the regulation of the expression levels of matrix metalloproteinases (MMPs), and the activated NF-kB signaling cascade was reported to upregulate MMP2 and MMP9 expression levels in HCC cells.…”

“…6,7 Although it was not associated with effects on cell survival, ICAM1 was linked to mediate cell adhesion and extravagation in both tumor progression and metastasis. 6,7 In addition, NF-kB was a key transcription factor in the regulation of the expression levels of matrix metalloproteinases (MMPs), and the activated NF-kB signaling cascade was reported to upregulate MMP2 and MMP9 expression levels in HCC cells. [8][9][10] Therefore, tight regulation and modulation of the NF-kB signaling cascade is necessary in HCC progression and malignancy.…”