Lung cancer (LC) with its different subtypes is generally known as a therapy resistant cancer with the highest morbidity rate worldwide. Therapy resistance of a tumor is thought to be related to cancer stem cells (CSCs) within the tumors. There have been indications that the lung cancer is propagated and maintained by a small population of CSCs. To study this question we established a panel of 15 primary lung cancer cell lines (PLCCLs) from 20 fresh primary tumors using a robust serum-free culture system. We subsequently focused on identification of lung CSCs by studying these cell lines derived from 4 representative lung cancer subtypes such as small cell lung cancer (SCLC), large cell carcinoma (LCC), squamous cell carcinoma (SCC) and adenocarcinoma (AC). We identified a small population of cells strongly positive for CD44 (CD44) and a main population which was either weakly positive or negative for CD44 (CD44). Co-expression of CD90 further narrowed down the putative stem cell population in PLCCLs from SCLC and LCC as spheroid-forming cells were mainly found within the CD44CD90 sub-population. Moreover, these CD44CD90 cells revealed mesenchymal morphology, increased expression of mesenchymal markers and , increased mRNA levels of the embryonic stem cell related genes and and increased resistance to irradiation compared to other sub-populations studied, suggesting the CD44CD90 population a good candidate for the lung CSCs. Both CD44CD90 and CD44CD90 cells in the PLCCL derived from SCC formed spheroids, whereas the CD44 cells were lacking this potential. These results indicate that CD44CD90 sub-population may represent CSCs in SCLC and LCC, whereas in SCC lung cancer subtype, CSC potentials were found within the CD44 sub-population.
Source: Identification and characterization of cells with cancer stem cell properties in human primary lung cancer cell lines. Wang P, Gao Q, Suo Z, Munthe E, Solberg S, Ma L, Wang M, Westerdaal NA, Kvalheim G, Gaudernack G (firstname.lastname@example.org). PLoS One. 2013;8(3):e57020.
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