Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2014 Jul 10;8(1):40-9.
doi: 10.1016/j.celrep.2014.05.036. Epub 2014 Jun 19.

Sox2 cooperates with Lkb1 loss in a mouse model of squamous cell lung cancer

Anandaroop Mukhopadhyay  1 , Kristofer C Berrett  1 , Ushma Kc  1 , Phillip M Clair  1 , Stelian M Pop  1 , Shamus R Carr  2 , Benjamin L Witt  3 , Trudy G Oliver  4
Affiliations

Sox2 cooperates with Lkb1 loss in a mouse model of squamous cell lung cancer

Anandaroop Mukhopadhyay et al. Cell Rep. .

Abstract

Squamous cell carcinoma (SCC) of the lung is the second most common subtype of lung cancer. With limited treatment options, the 5-year survival rate of SCC is only 15%. Although genomic alterations in SCC have been characterized, identifying the alterations that drive SCC is critical for improving treatment strategies. Mouse models of SCC are currently limited. Using lentiviral delivery of Sox2 specifically to the mouse lung, we tested the ability of Sox2 to promote tumorigenesis in multiple tumor suppressor backgrounds. Expression of Sox2, frequently amplified in human SCC, specifically cooperates with loss of Lkb1 to promote squamous lung tumors. Mouse tumors exhibit characteristic histopathology and biomarker expression similar to human SCC. They also mimic human SCCs by activation of therapeutically relevant pathways including STAT and mTOR. This model may be utilized to test the contribution of additional driver alterations in SCC, as well as for preclinical drug discovery.

PubMed Disclaimer

Figures

Figure 1
Figure 1. Lenti-Sox2;Lkb1fl/fl Tumors Express Biomarkers of Human SCC
(A) Left panels: two representative microCT images with tumor outlined in dashed blue lines and heart outlined in solid red lines in axial view. Middle panels: three-dimensional microCT reconstructions (3D recon) with lung tumors in blue. Right panels: gross morphology of dissected lungs with tumors indicated by blue arrows. Mouse IDs (JC156 and JC163) correspond to tumors in Table 1. (B) Lenti-Sox2;Lkb1fl/fl tumors and human SCC stained with H&E. Top scale bars represent 100 μM; bottom scale bars represent, 50 μM. (C) Representative KrasG12D/+ mouse lung adenocarcinomas, Lenti-Sox2;Lkb1fl/fl tumors, or human lung SCCs stained with K5, K14, p63, or TTF1. Scale bar represents 50 μM. (D) Average IHC score based on 0–5 scoring system where 5 indicates >90% positive; 4 indicates >75%; 3 indicates >50%; 2 indicates >25%; 1 indicates >10%; and 0 indicates negative. Human SCCs (n = 12), tumors from Table 1, and KrasG12D/+ adenocarcinomas were compared for K5, p63, and TTF1 IHC. Number of tumors analyzed is indicated in the color key. Error bars represent mean ± SEM. Student’s unpaired t test, *p = 0.02 for Sox2/Lkb1 versus Kras, and p = 0.04 for Sox2/Lkb1 versus human SCC. See also Figure S1.
Figure 2
Figure 2. Lenti-Sox2;Lkb1fl/fl Tumors Express Sox2 and Exhibit Activation of the mTOR Pathway Similar to Human SCCs
(A) Representative IHC of Sox2, p4EBP1, and pAMPK in KrasG12D/+ mouse lung adenocarcinomas, Lenti-Sox2;Lkb1fl/fl tumors, human lung SCCs, and KrasG12D/+Lkb1fl/fl squamous tumors. Brown/red staining is positive. Scale bar represents 50 μm. (B) Average IHC scores for Sox2 and p4EBP1 from individual tumors indicated in Table 1 based on 0–5 scoring system where 5 indicates >90% positive; 4 indicates >75%; 3 indicates >50%; 2 indicates >25%; 1 indicates >10%; and 0 indicates negative. Number of tumors analyzed is indicated in color key at right. Error bars represent mean ± SEM. Student’s unpaired t test, ****p < 0.001. (C) PCR validation of Lkb1 recombination in tumor samples from mice indicated in Table 1. Wild-type (WT), floxed (flox), and recombined (del) Lkb1 alleles indicated. Actin serves as input control. Mixed 1:1 Lkb1 WT and floxed DNA, Lkb1+/+, and Lkb1fl/fl normal lung DNA serve as controls. (D) Left panels: representative images of Sox2− and p4EBP1-positive and -negative IHC. Right panels: contingency table of human SCCs (n = 12) stained with antibodies to SOX2 and p4EBP1. See also Figure S2.
Figure 3
Figure 3. Murine SCCs Exhibit Expression of Potential Therapeutic Targets
(A) Representative IHC of KrasG12D/+ mouse lung adenocarcinomas, mouse Lenti-Sox2;Lkb1fl/fl tumors, human lung SCCs, and KrasG12D/+Lkb1fl/fl squamous tumors stained with indicated antibodies. Brown/red staining is positive. Scale bar represents 50 μm. (B) Average IHC score of FGFR2, pErk, pAkt, and pStat3 stains in individual tumors from Table 1, human SCCs, and KrasG12D/+Lkb1fl/fl squamous tumors. Number of tumors analyzed is indicated in color key at right. IHC scoring system is based on scoring system where 5 indicates >75% positive; 4 indicates >50%; 3 indicates >25%; 2 indicates >10%; 1 indicates >2.5%; and 0 indicates negative. Error bars represent mean ± SEM. For Student’s unpaired t test, *** indicates p < 0.0002 and *p < 0.01. (C) Immunoblot of cytoplasmic (c) and nuclear (n) protein extracts for SOX2, pStat3, and NF-κB p65 from human lung cancer cell lines under control (−) or 48 hr SOX2 induction (+) in stable Tet-On cells. Nemo and Parp serve as loading controls for cytoplasmic and nuclear fractions, respectively. See also Figure S3.
See this image and copyright information in PMC

Similar articles

See all similar articles

Cited by

See all "Cited by" articles

References

    1. Bass AJ, Watanabe H, Mermel CH, Yu S, Perner S, Verhaak RG, Kim SY, Wardwell L, Tamayo P, Gat-Viks I, et al. SOX2 is an amplified lineage-survival oncogene in lung and esophageal squamous cell carcinomas. Nat Genet. 2009;41:1238–1242. - PMC - PubMed
    1. Boyer LA, Lee TI, Cole MF, Johnstone SE, Levine SS, Zucker JP, Guenther MG, Kumar RM, Murray HL, Jenner RG, et al. Core transcriptional regulatory circuitry in human embryonic stem cells. Cell. 2005;122:947–956. - PMC - PubMed
    1. Brcic L, Sherer CK, Shuai Y, Hornick JL, Chirieac LR, Dacic S. Morphologic and clinicopathologic features of lung squamous cell carcinomas expressing Sox2. Am J Clin Pathol. 2012;138:712–718. - PubMed
    1. Cancer Genome Atlas Research Network. Comprehensive genomic characterization of squamous cell lung cancers. Nature. 2012;489:519–525. - PMC - PubMed
    1. Ding L, Getz G, Wheeler DA, Mardis ER, McLellan MD, Cibulskis K, Sougnez C, Greulich H, Muzny DM, Morgan MB, et al. Somatic mutations affect key pathways in lung adenocarcinoma. Nature. 2008;455:1069–1075. - PMC - PubMed

Publication types

MeSH terms