Figure 2
From: The pluripotency factor NANOG promotes the formation of squamous cell carcinomas
Nanog overexpression promotes skin squamous cell carcinoma.
(A) Experimental layout for two-stage chemically-induced carcinogenesis. CTR and TG mice (see Fig. 1A) were treated with doxycycline (DOX) in their drinking water (2 mg/ml) during the entire protocol. DMBA was applied 48 hr after initiation of DOX treatment. TPA application started the following week, twice a week during 15 weeks. Tumors were counted and measured weekly. Histological analysis was performed at the humane endpoint or at the end of the experiment (30 weeks). (B) Average number of tumors per mouse during the treatment. Statistical significance was determined for each time point by two-tailed Student’s t test: (*) p < 0.05. (C) Representative images of DMBA/TPA treated mice. Arrow indicates a squamous cell carcinoma. (D) Hematoxylin and eosin (H&E) staining of TG carcinomas and lymph node metastasis. Two magnifications are shown for each tissue (bars correspond to 200 μm in the low magnification pictures and to 50 μm in the high magnification pictures). (E) Left, percentage of CTR and TG mice with squamous cell carcinomas (SCCs) at the end of the treatment. Right, conversion rate showing the number of SCCs relative to the total number of tumors. Statistical significance was assessed by the Fisher’s exact test: (**) p < 0.01. (F) Top, immunoblots of NANOG using total lysates from the indicated cell lines. γTUBULIN was used as a loading control. Bottom, endogenous Nanog mRNA levels from the indicated cell lines. Mouse ESCs were used as a positive control for Nanog expression. mRNA levels were normalized by Gapdh levels. Values correspond to the mean ± SD of two independent isolates (n = 2), each one analyzed in triplicate. SpSCC, spindle SCC.
