KRT18

Case study 1: Ruizan Shi, 2020

Induction of epithelial-mesenchymal transition (EMT) and cancer stem cell (CSC) characteristics underlie the development of metastasis, chemoresistance, and tumor recurrence in breast cancer. Downregulation of cytokeratin 18 (CK18) is a critical molecular event of EMT; however, its importance in the induction of EMT and CSC features has not been defined to date. This study aimed to investigate the biological significance and underlying molecular mechanisms of CK18 in inducing EMT phenotype and stemness properties of breast cancer cells.

CK18 expression was extremely low in highly metastatic, resistant, and transforming growth factor (TGF)-β1/tumor necrosis factor (TNF)-α-treated breast cancer cells with mesenchymal phenotype and increased expression of CSC markers. Depletion of CK18 promoted partial EMT and the acquisition of stemness properties in breast cancer MCF-7 cells. Mechanistically, CK18 interference in MCF-7 cells activated the Wnt/β-catenin signaling. In conclusion, downregulation of CK18 promotes partial EMT and enhances breast cancer stemness by increasing EpCAM expression partly via the Wnt/β-catenin pathway.

Fig1. The expression of EMT markers (E-cadherin, N-cadherin, and Vimentin), stemness markers (Oct4, Klf4, and Sox2), and CK18 in MCF-7, MDA-MB-231, and MCF-7/MX cells was detected using western blot assay.

Fig2. Expression of EpCAM (green) in MCF-7 and MCF-7-shCK18 cells was analyzed by immunofluorescence staining and DAPI (blue).

Case study 2: Kenta Soeta, 2020

Cytokeratin (CK) 18 is an intermediate filament protein that plays a major functional role in the integrity and mechanical stability of cells. CK18 is also cleaved by some caspases during apoptosis. Three-dimensional (3D)-cultured cancer cells are useful for cancer research as an intermediate model between in vitro cancer cell line cultures and in vivo tumors.

In this study, the researchers produced rat monoclonal antibodies (mAbs) through immunization of the lysate from 3D-cultured DLD-1 cells to elucidate a characteristic feature of a tumor, and the results showed that mAb 2H7 recognized human CK18.

Fig3. Comparison of recognition of endogenous CK18 by mAb 2H7 and mouse mAb through immunoblotting using several human cell lines.

Fig4. Immunofluorescence staining of mAb 2H7 and mouse mAb using DLD-1 cells. DLD-1 cells were immunostained with mAb 2H7 or anti-CK18 mAb.

KRT18 involved in several pathways and played different roles in them. We selected most pathways KRT18 participated on our site, such as Pathogenic Escherichia coli infection, which may be useful for your reference. Also, other proteins which involved in the same pathway with KRT18 were listed below. Creative BioMart supplied nearly all the proteins listed, you can search them on our site.

KRT18 has several biochemical functions, for example, poly(A) RNA binding, protein binding, scaffold protein binding. Some of the functions are cooperated with other proteins, some of the functions could acted by KRT18 itself. We selected most functions KRT18 had, and list some proteins which have the same functions with KRT18. You can find most of the proteins on our site.

KRT18 has direct interactions with proteins and molecules. Those interactions were detected by several methods such as yeast two hybrid, co-IP, pull-down and so on. We selected proteins and molecules interacted with KRT18 here. Most of them are supplied by our site. Hope this information will be useful for your research of KRT18.

KRT8; YWHAZ; DNAJB6; TRADD