Abstract 632: Establishment and characterization of xenografts and cell lines trom nasopharyngeal carcinoma

Abstract

Nasopharyngeal carcinoma (NPC) is a common cancer among ethnic Cantonese living in Hong Kong and southern China. It is closely associated with Epstein-Barr virus (EBV) infection. Unfortunately, there are very few representative xenografts and cell lines established from NPC available for investigation. Most of the NPC xenografts established have been passaged in immune deficient animals for over 20 years and may not be representative of the original NPC in patients. For in vitro NPC cell lines, there is only one cell line which retains the EBV genomes. Other NPC cell lines have all lost their EBV episomes. Furthermore, many of these NPC cell lines are found to be contaminated with genetic components from HeLa cells (HPV16 genome) which raised issues on their origins and limited their uses as NPC cells. There is great urgency in establishment new NPC cell lines both in vivo and in vitro for various research investigations and for the study of pathogenic role of EBV infection in NPC. We have carried out continuous efforts since 2010 to attempt establishment of new NPC xenografts and cell lines from surgical and biopsies NPC tissues. NPC tissues from resected recurrent NPC and biopsies from primary NPC were explanted to subrenal capsular sites and maintained for four months to one year to observe for growth of new NPC xenografts. Attempts to establish new NPC celles were also carried out. At present, we have successfully established 3 NPC xenografts (Xeno 23, Xeno 32, Xeno 47) which could be passages at subcutaneously sites and one in vitro NPC cells (NPC43) which harbors EBV genomes. The growth properties and genetic alterations of these newly established NPC cell lines have been characterized. Novel genetic alterations and growth signaling pathways were observed in these newly established NPC cell lines and may represent driver mutations and signaling pathways essential for progression of NPC. Profiling of EBV gene expression of these newly established NPC cell lines revealed predominant latent EBV infection and expression of EBV-encoded mRNA from the BART transcripts which are characteristic of EBV infection in NPC. The establishment of new NPC cells will contribute to investigate the pathogenesis of NPC and its intimate relationship with EBV infection. Funding acknowledgement: University Grant Council (HK) grants (AoE NPC (AoE/M-06/08); TBRS (T12-401/13R); GRF); University of Hong Kong (CRCG and SRT cancer) Citation Format: WT Lin, L Xia, Dan Dan Wen, CM Tsang, KW Lo, ML Lung, George Sai-Wah Tsao. Establishment and characterization of xenografts and cell lines trom nasopharyngeal carcinoma. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 632.

Significance of Expression of Human METCAM/MUC18 in Nasopharyngeal Carcinomas and Metastatic Lesions

“…However, it is not clear if this is applicable to NPC cell lines, so that the low expression levels of huMETCAM/MUC18 in NPCs may promote tumorigenesis and metastasis. Consistent with this notion, the two NPC cell lines, which only expressed about 6-11 % of the protein in comparison with that in SK-Mel-28 cells, were previously shown that they were able to form tumor subcutaneously and to establish metastatic lesions on the surface of diaphragm and in lung parenchyma and liver, when the very high number of cells (5 x 10 7 cells) were subcutaneously injected into Balb/c nude mice ( (Lin et al, 1990;Lin et al, 1993). However, the possibility that this might be an experimental artifact of injecting a very high number of cells in immunodeficient mice can not be completely ruled out until the results of a similar animal test by using a much lower number of cells for injection are confirmed.…”

“…Two NPC cell lines, NPC-TW01 and NPC-TW04, were from Dr. Chin-Tarng Lin, Department of Pathology, National Taiwan University, Taipei, Taiwan (Lin et al, 1990;Lin et al, 1993). Anti-huMETCAM/ MUC18 antibody was prepared from chicken immunized with the middle fragment of a recombinant huMETCAM/ MUC18 protein, which was over-expressed in E. coli (Wu et al, 2001a;Wu et al, 2001b;Wu, 2004).…”

“…The mean expression level of huMETCAM/MUC18 in NPC tissues was about 1/5 of that in the normal counterparts and metastatic lesions. Figure 2 shows the expression of huMETCAM/MUC18 protein in two established NPC cell lines, NPC-TW-01, which was established from a keratinizing squamous nasopharyngeal carcinoma (WHO type I), and NPC-TW-04, which was established from a (Lin et al, 1990;Lin et al, 1993). As shown in Figure 2, the molecular weight of huMETCAM/ MUC18 expressed in NPC-TW01 was similar to that in other cancer cell lines, but that in the NPC-TW04 was slightly lower than that in most of human cancer cell lines.…”

Nasopharyngeal Carcinoma: An Evolving Role for the Epstein–Barr Virus

“…Early studies using renaturation kinetics determined that the viral genome was essentially the same as that found in BL and during IM and that the viral genome was maintained as an extrachromosomal episome within the nucleus (Pagano et al 1975;Nonoyama and Pagano 1972). However, unlike EBV infection of B cells, epithelial cells are extremely difficult to infect and the viral genome is frequently not maintained in stable cell lines established from the tumors (Dittmer et al 2008;Cheung et al 1999;Lin et al 1990). Thus, much of the early molecular biology of NPC utilized biopsy material and rare examples of NPC that could grow as xenografts in nude mice (Raab-Traub et al 1983;Busson et al 1988).…”

“…Surprisingly, the viral genome is frequently lost in epithelial cell lines established from EBV (Dittmer et al 2008;Lin et al 1990). In BL cell lines, the loss of EBV results in cell death (Vereide and Sugden 2009;Kennedy et al 2003).…”