Abstract 1399: Characterization of cancer stem cell properties and identification of invasion as well as metastatic process in head and neck cancer
Authors: Gunduz Mehmet , Hatipoglu Omer Faruk , Gunduz Esra , Cetin Elif Nihan , Uctepe Eyyup , Cigdem Sadık , Grenman Reidar , Acar Muradiye 
Published: August 2015

Abstract
Cancer stem cells (CSC) are thought to be a sub-population of cancer cells, which are the main tumorigenic cells in the tumors. Although chemoradiotherapy may kill the majority of rapidly dividing cells, CSC-like cell populations may be left behind due to their low turnover and infrequent cell cycling. In 2007, Prince et al. reported the presence of head and neck cancer stem cells for the first time.
In the current study, UTTSCC74A and UTTSCC74B head and neck cancer cell lines as material derived from the primary tumor and their lymph node metastasis, respectively, were used. FACS was used for isolation of cancer stem cells using antibodies against CD44 and ALDH1. However we could not get specific response from CD44 antigen ie can not isolate cancer stem cell. However ALDH1 antibody selection gave us isolation of cancer stem cells from both of UTTSCC74A and B cell lines though much less cancer stem cells existed in UTTSCC74B cell line. The cells were first cultured in normal DMEM with 10% FBS under the condition of 5% CO2. Then the cells were changed into stem cell medium and cultured. Cancer stem cells were isolated using antibody against ALDH1 and these cells were cultured in stem cell medium and its characteristics were confirmed through sphere formation as well as immunofluorescence staining with antibody against ALDH1 and control antibody against DAPI. Expressions of sox-2, oct-4 and klf-4 were confirmed. After characterization of cancer stem cell from head and neck cancer cell line was confirmed, microarray analysis were performed using Gene Chip PrimeView Human expression Array (U133-HG133/ 47,000 transcript). Each group of ALDH1+ (cancer stem) and - cells isolated from each of UTTSCC74A and UTTSCC74B cell lines were exposed to microarray analysis. RNA extraction and cDNA construction from each sub group were prepared for microarray analysis. Comparison of UTTSCC74A ALDH1+ and - provided increased expression of 2037 and decreased expression in 2263 genes in various ratios. Similarly comparison of UTTSCC74B ALDH1+ and - provided increased expression of 6349 and decreased expression in 5322 genes in various ratios. 26 genes with most up and down regulation were selected and confirmation was done through real-time RT-PCR designing custom primers. Similar results were taken as in microarray analysis. From these 26 genes with confirmation of their expressions, 5 up regulated and 5 downregulated genes were selected for further analysis. We currently prepare expression plasmids of these genes and continue their in vitro functional analysis.
Thus, the identification of the cancer-stem cell related signalling pathways in head and neck cancer stem cell would provide valuable information for a better understanding of cancer stem cell properties, molecular mechanisms of carcinogenesis, invasion and metastasis in this cancer type. By this way, effective therapeutic options targeting CSCs may be developed.
Citation Format: Mehmet Gunduz, Omer Faruk Hatipoglu, Esra Gunduz, Elif Nihan Cetin, Eyyup Uctepe, Sadık Cigdem, Reidar Grenman, Muradiye Acar. Characterization of cancer stem cell properties and identification of invasion as well as metastatic process in head and neck cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 1399. doi:10.1158/1538-7445.AM2015-1399