PO-296 Elucidating the potential role of CD109 as a biomarker for cancer stem-like cells in cervical cancer

Abstract

IntroductionCervical cancer is a common genital tract cancer. Radiotherapy is the mainstay of management for advanced cervical cancer. Response to radiation varies widely which may be explained by the existence of cancer stem-like cells (CSCs). Since CSCs is implicated in cervical cancer and demonstrated a high degree of resistance to radiation, the identification of novel CSC markers could be critical to specifically target the cervical CSC. In our pilot study, we established attached and spheroid cells from primary cervical tumour tissue. Multiple ‘stemness’ genes were detected in spheroid cells which indicated primary cervical cancer tissue harboured CSCs population. cDNA microarray analysis was performed to compare cDNA expression profile and CD109 was significantly up-regulated in spheroid cells. Therefore, we hypothesise that CD109 may serve as a potential cervical CSCs marker.Material and methodsFlow cytometry was performed to analyse the CD109 expression and isolate the CD109 positive and negative sub-populations in cervical cancer cells. Following the sorting, cell proliferation and migration assay were performed. In order to investigate the effect on the blockade of CD109, SiHa, Caski and C4-1 cells were transfected with CD109 siRNAs. XTT assay, migration and invasion assay and spheroid formation assay were performed. Immunohistochemistry (IHC) was performed for the detection of CD109 expression in cervical cancer tissue microarray (TMA).Results and discussionsThe post-sorted CD109 (+) cells grew remarkably faster and have stronger migration capability than CD109(-) cells in Caski and C4-1. The CD109 knockdown cells with siRNA exhibited a slower cell growth, decreasing migration and self-renewal ability, as compared with the control group in SiHa, Caski and C4-1 cells. IHC of TMA indicated that CD109 was highly expressed in cancer cases than that in normal/benign cases.ConclusionCD109 increased cell proliferation rate and migration ability in post-sorted cervical cancer cell lines Caski and C4-1. On the contrary, CD109 knockdown reduced cell growth, migration and self-renewal capability in cervical cancer SiHa, Caski and C4-1 cells. Cervical carcinoma showed high expression of CD109 protein by IHC. Further in vivo and in vitro functional assays are essential to characterise the CD109-positive sub-population in cervical cancer which may provide more information of cervical CSCs-related properties and resistance of radiation therapy, with the underlying molecular mechanism involved.