P-214 - Pattern of Dipkoff-2 gene expression in tumoral tissues of colorectal cancer and two tumor tissues of colorectal cancer and three cell lines (HUVEC,...

Date 04 July 2015
Event WorldGI 2015
Session Posters
Topics Basic Science
Colon Cancer
Rectal Cancer
Translational Research
Presenter F. Khodarahmi
Citation Annals of Oncology (2015) 26 (suppl_4): 1-100. 10.1093/annonc/mdv233
Authors F. Khodarahmi1, M.S. Fazeli2, H. Mahmoodzadeh2, A. Mehrtash3, N. Keikhosravi4, M. Ghadir3, L. Teimoori-Toolabi3
  • 1Department Of Genetics, Tehran Medical Sciences Branch, Islamic Azad University, Tehran/IR
  • 2Tehran University of Medical Sciences, Tehran/IR
  • 3Pasteur Institute of Iran, Tehran/IR
  • 4Molecular Medicine Department, Biotechnology Research Center, Pasteur Institute of Iran, Tehran/IR

Abstract

Introduction

The Wnt signaling pathway, which plays important roles in embryogenesis, development and homeostasis, is also closely linked to carcinogenesis of Colorectal cancer (CRC). There are different modulators of this pathway such as Dickkopf 2 (DKK2) that are assumed to play a dual role as a tumor suppressor gene or an oncogene. In this study we studied the expression of DKK2 in 10 patients affected with colorectal cancer also we examine expression status of this gene in three cell lines including SW480, HCT116 (colon cancer cell lines) and HUVEC, in addition to two tumor tissue of colorectal cancer.

Methods

Total RNA was extracted using TRIzol reagent thereafter cDNA was synthesized by Mu-MLV reverse transcriptase. The studied cell lines had been obtained from ATCC. Fresh tumor tissues of colorectal cancer were obtained from Imam Khomeini Hospital (Tehran, Iran). Total RNA of samples and cells were extracted using TRIzol and converted to cDNA using Mu-MLV reverse transcriptase. The expression of DKK2 and GAPDH (as the reference gene) in tumoral tissues was studied by using primers, probe, and Taqman master mix (TAKARA) while in cell lines the expression was studied by SYBR Green MasterMix.

Results

The age of patients was from 37 to 84 years old. Tumor and normal adjacent samples were obtained from 5 females (who suffered from colorectal cancer in colon, rectum and sigmoid sites) and 5 male patients (who suffered from colorectal cancer in colon, rectum and rectosigmoid sites) from Imam Khomeini Hospital (Tehran, Iran). In 100% of cases DKK2 was expressed in normal and tumoral tissues. In 90% of patients downregulation of this gene in tumoral tissue relative to adjacent normal tissues was seen (ΔΔCTs in males: -0.64, -1, -4.32, -8.27, -1.93 and in females: -1.46, -4.32, -1.1, -6.73) while in one tumor tissue (female, rectal cancer) overexpression of DKK2 was seen (ΔΔCT: 0.29). ΔΔCTs of DKK2 in tumor tissues (obtained from a 49 year old female and 70 year old male) in comparison to HUVEC were -0.88 and -0.97 while ΔΔCTs of DKK2 in SW480 and HCT116 in comparison to HUVEC were -4.65 and -3.35.

Conclusion

While DKK2 gene was observed to be downregulated in malignant melanoma and human ovarian carcinoma, it had been claimed that it was upregulated in primary colorectal cancers and even in adenomas. Our observations showed that DKK2 expression was downregulated in tumoral and to a greater extent in HCT116 and SW480 cancer cell lines in comparison to normal ones. While in the previous studies it was claimed that DKK2 expression was absent or barely detectable in SW480 and HCT116 cell lines and it is upregulated in primary colorectal cancers and even in adenomas, our study showed that generally expression of this gene was downregulated in colorectal cancer tissues and cells which should be validated more.