Fig. 1: p53 restoration limits SCLC growth and metastasis in vivo. | Nature Communications

Fig. 1: p53 restoration limits SCLC growth and metastasis in vivo.

From: p53 restoration in small cell lung cancer identifies a latent cyclophilin-dependent necrosis mechanism

Fig. 1

a Schematic of the p53XTR allele. Top, p53XTR (expressed): XTR gene trap cassette consists of a splice acceptor (SA), enhanced Green Fluorescent Protein (GFP), and the polyadenylation transcriptional terminator (pA). Stable inversion is achieved by the use of two pairs of mutually incompatible mutant loxP sites (Lox2272 and Lox5171) arranged in the ‘double-floxed’ configuration. Middle, p53TR (trapped): inhalation of Cre-expressing adenoviral vectors induces permanent gene trap inversion and conversion to the p53TR allele inactivating Trp53 expression. Transcripts are spliced from exon 1 to the GFP reporter. Bottom, p53R (restored): the Rosa26FlpO-ERT2 allele enables tamoxifen-dependent conversion of trapped p53TR to its restored p53R allelic state via excision of the gene trap. b RPR2 and RPXTRR2 mice were infected with 1.0 × 108 p.f.u of Ad:CMV-Cre to initiate tumor formation. Between 25–28 weeks after tumor initiation, mice were treated with vehicle or tamoxifen, as described. c H&E and IHC for the neuroendocrine markers, ASCL1, CGRP, and UCHL1 in RPR2, RPTRR2 and KP mice. Scale bars: 25 μm for H&E, 25 μm for IHC; insets are magnified 5×. d Representative scans of tumor-bearing lobes from RPR2 or RPTRR2 mice. e Tumor burden 25–28 weeks after tumor initiation. RPTRR2 and RPR2, n = 3 mice. Statistical significance was determined by two-tailed Student’s t-test. Error bars represent mean ± s.d. f Brightfield and fluorescent micrographs of lungs from RPTRR2 mice treated with vehicle (Control) or tamoxifen (Restored). Scale bars: 4.4 mm (g) Kaplan-Meier survival analysis. RPTRR2, n = 10 mice per treatment group (Control or Restored); RPR2, n = 10 mice. Statistical significance determined by Mantel-Cox log rank test. h Brightfield and fluorescent micrographs of metastatic liver nodules from control RPTRR2 mice. Scale bars: 4.4 mm (i) Quantification of metastatic liver nodules in control (n = 3 mice) and restored (n = 3 mice) after 9–16 days of tamoxifen treatment. Error bars represent mean ± SEM. Statistical significance determined by one-tailed Student’s t-test. Source data are provided as a Source Data file.

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