Indian Journal of Experimental Biology Vol. 47, May 2009, pp. 327-332 Mouse acquired HPV tumor using dorsal skin-fold window chamber Monthon Lertworapreecha 1 , Suthiluk Patumraj 2 , Somchai Niruthisard 3 , Pokrath Hansasuta 4 & Parvapan Bhattarakosol 4* 1 Inter-Department of Medical Microbiology, Graduate School, Departments of 2 Physiology, 3 Gynaecology and 4 Microbiology, Faculty of Medicine, Chulalongkorn University, Rama 4 road, Bangkok 10330, Thailand Received 27 November 2008; revised 24 February 2009 Human papillomavirus (HPV) plays important role in developing several types of cancer especially cervical cancer. In order to understand the viral pathogenesis, the animal model of HPV infection is very necessary. This communication reports establishment of an animal model carrying implanted HeLa cells, a human cervical cancer cell line via dorsal skin- fold window chambers. Nude mice were divided into 4 groups; each group contained different amount of HeLa cells, 2.5×10 5 , 5×10 5 , and 1×10 6 cells, and cell free medium (control), respectively. The results showed that even using the low number of HeLa cells (2.5×10 5 ), the tumor microvasculature was developed at 2 weeks after implantation with the enlarged tumor margin which then progressed to tumor mass in the following week. The existing tumor was confirmed to be HeLa- cell type by PCR, in situ hybridization, and HPV genotyping. By using linear regression analysis, it indicated that means of tumor size from each group significantly increased in relation to number of HeLa cells used (R 2 = 0.98, y = 0.1171x+4.35). This mouse model will be useful for the further HPV studies particularly anti-cancer drugs efficacy. Keywords: Dorsal skin-fold window chamber, HPV Tumor, Mouse model Human papillomavirus (HPV) is a naked, icosahedral capsid, about 8 kb circular double stranded DNA virus, belonging to the family Papillomaviridae 1 . At present more than 150 different HPV types have been reported 2 . Approximately 40 types of HPV involve in anogenital tract infection and they can be classified as high risk (i.e., HPV 16, 18, 31, 33, and 35) and low risk (i.e., HPV 6 and 11) types according to the spectrums of their abilities to induce cancers 2,3 . Unlike other viruses, HPV is highly host-specific, unable to propagate in normal cell culture and its replication cycle requires the differentiation process of keratinocytes 2,4 . Thus, the interaction of virus and host is not well understood. Many attempts have been made using several means to develop animal model, starting from direct inoculation of HPV extracted from naturally human lesion to human neonatal foreskin and then grafted underneath the renal capsule of athymic mice 5 , direct transplant tumor tissue by xenograft technique and development of transgenic mice containing HPV E6 gene 6,7 . An attempt has been made by inoculating HPV transformed cervical cell line, HeLa, into dorsal skin- fold window chamber. An animal model carrying human cervical cancer cells was conducted. The implanted mice were monitored for their weight changes and size of tumor. The tumor microvasculature was also investigated under an intravital fluorescence videomicroscope. In addition, tumor lesion was then confirmed to be HeLa mass by using PCR technique, in situ hybridization, and HPV genotyping. Materials and Methods Animals―Female BALB/c-nude mice from National Laboratory Animal Center of Salaya Campus, Mahidol University, Bangkok, Thailand aged 4-8 weeks and weighing 20-25 g were used. The animals were handled as recommended by the guide for the care and use of experimental animals 1996, Institute of Laboratory Animal Resources, Commission on Life Sciences, National Research Council, USA. Cervical cancer cell line―HeLa cell is a human cervical cancer cell line which contains integrated HPV-18 genome approximately 10-30 copies/cell 8 . The cells were cultured in MEM medium (HyClone; USA) supplemented with 10% heat-inactivated fetal bovine serum (HyClone, USA), penicillin (50 unit/ml) and streptomycin (50 µg/ml) with split ratio of 1:3. They were subcultured every 2-3 days regularly to __________ *Correspondent author Telephone: 66-2-256-4132; ext. 616 Fax: 66-2-252-5952 E-mail: parvapan@chula.ac.th