Immortalization is an essential process of the transformation of cells to a neoplastic growth. High risk human papillomavirus (hrHPV) infection has been the major cause of head and neck squamous cell carcinoma (HNSCC). The aim of this study was to search for a novel pathway causing immortalization in HPV16 E6/E7 transfected immortalized oral keratinocytes (IHOK). hrHPV integration sites were identified through DNA sequencing. HPV16 E6/E7 genes were integrated into 1q32.2, 12q21.2, 15q15.2, and 19q13.43 in IHOKs. Array-CGH was conducted to examine the deranged sites of the genes of IHOK. Of the 587 amplification genes, 70 genes were resided on chromosome 20. We selected PLAGL2 and MAPRE1 as the most amplified genes. PLAGL2 and MAPRE1 mRNA showed higher expression in IHOK than in normal keratinocytes. Knockdown of MAPRE1 significantly reduced telomerase activity. The analysis using a public database substantiated our data, showing the amplification of chromosome 20 and MAPRE1. In conclusion, our results suggest that MAPRE1 could play a crucial role in activating telomerase activity in hrHPV-infected cells. This finding may provide basic data to develop a novel target therapy for hrHPV-related HNSCC.

A cell line of bovine origin was immortalized to isolate foot-and-mouth disease virus (FMDV). The immortalization was performed by infection of bovine primary epithelial cells with a recombinant retrovirus that overexpressed the human telomerase (hTERT), after primary culture of fetal bovine kidney tissue and removal of fibroblasts. After cloning the immor- talized cell line into single cells, the cloned cell lines were named JNUBK-1, JNUBK-2, JNUBK-3 and JNUBK-4, according to their characteristics. To confirm the epithelial phenotype of the cell lines JNUBK-3 and JNUBK-4, which showed stable proliferation capability over 35 generations after immortalization, the expression of cytokeratin and fibronectin was measured. Finally, the FMDV titer in the JNUBK-3 and JNUBK-4 cell lines was measured and was 800∼2,000 times higher than that of the currently used cell line IRBS-2. In conclusion, more sensitive isolation and production of FMDV became possible through the use of the immortalized JNUBK-3 and JNUBK-4 cell lines.

Trophoblasts, in the placenta, play a role for placental development as well as implantation in the early pregnancy. The characteristics and functions of trophoblast are identified by their localization and potency for proliferation, differentiation, and invasion. Thus, inadequate trophoblast cell death induces trophoblast dysfunction resulting in abnormal placental development and several gynecological diseases. Recently, it was reported that increased immortalization-upregulated protein-2 (IMUP-2) by hypoxia influences trophoblast apoptosis. However, IMUP-2 function on autophagy, which is type II programmed cell death remains unclear. In this study, we analyzed IMUP-2 expression in trophoblast cells (HTR8-SVneo) and compared IMUP-2 effects on cell death including apoptosis and autophagy in trophoblast regardless of IMUP-2 expression. Increased IMUP-2 in trophoblast by IMUP-2 gene transfection induces cell death, especially, apoptosis increases more than autophagy (p<0.05). However, the decreased IMUP-2 in trophoblasts after siRNA treatment decreased apoptosis with the decreased activities of caspase 3 and 7. The expressions of LC3 and MDC as an autophagosome makers and phosphorylated mTOR, which is a negative regulator for autophagy, increased. In addition, the S phase of cell cycle increased in trophoblasts when IMUP-2 expression decreased. Taken together, the alteration of IMUP-2 can control the balance between apoptosis and autophagy of trophoblasts resulting in functional involvement in placental development and in gynecological diseases by regulating the function of trophoblasts.