ETK-1

ETK-1 is a human intrahepatic cholangiocarcinoma (IHCCA) cell line originally established from the ascitic fluid of an adult patient with sarcomatoid cholangiocarcinoma. The tumor from which ETK-1 was derived exhibited both tubular adenocarcinoma and sarcomatoid components, and the cell line reflects the sarcomatoid phenotype. ETK-1 cells grow adherently as a uniform epithelial monolayer with a cobblestone appearance, composed mainly of small polygonal cells with round to oval nuclei and prominent nucleoli. Early passage cells demonstrated a population doubling time of approximately 70 hours and a hyperdiploid karyotype with a modal chromosome number in the mid-70s, consistent with chromosomal instability typical of aggressive biliary tract malignancies.

Immunophenotypically, ETK-1 cells express biliary epithelial markers including γ-glutamyl transpeptidase (GGT), cytokeratin 18 (CK18), and cytokeratin 19 (CK19), confirming their cholangiocytic origin. They are negative for hepatocyte-associated markers such as alpha-fetoprotein (AFP) and albumin under basal conditions. ETK-1 cells express vimentin, reflecting their sarcomatoid characteristics and partial mesenchymal phenotype, while lacking expression of carcinoembryonic antigen (CEA) and carbohydrate antigen 19-9 (CA19-9). This marker profile corresponds to the sarcomatoid component observed in the primary tumor and highlights features consistent with epithelial-mesenchymal transition-like properties.

ETK-1 has also been used as a model to study cellular plasticity and lineage differentiation in cholangiocarcinoma. Treatment with the DNA methyltransferase inhibitor 5-azacytidine induced morphological and phenotypic changes, resulting in a derivative cell line with hepatocyte-like features, including expression of AFP, albumin, integrin α1, and thrombopoietin, along with loss of certain biliary markers. In xenograft models, untreated ETK-1 cells form tumors consistent with tubular adenocarcinoma displaying a ductal phenotype. These findings demonstrate that ETK-1 retains differentiation plasticity and serves as a valuable in vitro system for investigating biliary epithelial-to-hepatocytic transdifferentiation, epigenetic regulation, and tumor heterogeneity in intrahepatic cholangiocarcinoma.

37°C, 5% CO₂, humidified atmosphere.

1. Confirm that the vial remains deeply frozen upon delivery, as cells are shipped on dry ice to maintain optimal temperatures during transit.

2. Upon receipt, either store the cryovial immediately at temperatures below -150°C to ensure the preservation of cellular integrity, or proceed to step 3 if immediate culturing is required.

3. For immediate culturing, swiftly thaw the vial by immersing it in a 37°C water bath with clean water and an antimicrobial agent, agitating gently for 40-60 seconds until a small ice clump remains.

4. Perform all subsequent steps under sterile conditions in a flow hood, disinfecting the cryovial with 70% ethanol before opening.

5. Carefully open the disinfected vial and transfer the cell suspension into a 15 ml centrifuge tube containing 8 ml of room-temperature culture medium, mixing gently.

6. Centrifuge the mixture at 200 x g for 5 minutes, carefully discard the supernatant containing freezing medium.

7. Follow the procedure described under Post-Thaw Recovery

For long-term preservation, place vials in vapor-phase liquid nitrogen at about −150 to −196 °C. Storage at −80 °C is acceptable only as a short interim step before transfer to liquid nitrogen.

Cryopreserved cell lines are shipped on dry ice in validated, insulated packaging with sufficient refrigerant to maintain approximately −78 °C throughout transit. On receipt, inspect the container immediately and transfer vials without delay to appropriate storage.

At Cytion, we stand behind the quality and viability of our products. We guarantee that our cells will be viable at the start of culture for 60 days after shipment from our facilities. We assure that all materials conform to the specifications described in the Certificate of Analysis and/or Product Sheet.

For full details, please refer to our Warranty Statement.