Notch-effector CSL promotes squamous cell carcinoma by repressing histone demethylase KDM6B
Dania Al Labban, … , Renato Panizzon, G. Paolo Dotto
Dania Al Labban, … , Renato Panizzon, G. Paolo Dotto
Published May 14, 2018
Citation Information: J Clin Invest. 2018;128(6):2581-2599. https://doi.org/10.1172/JCI96915.
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Research Article Cell biology Oncology

Notch-effector CSL promotes squamous cell carcinoma by repressing histone demethylase KDM6B

Abstract

Notch 1/2 genes play tumor-suppressing functions in squamous cell carcinoma (SCC), a very common malignancy in skin and internal organs. In contrast with Notch, we show that the transcription factor CSL (also known as RBP-Jκ), a key effector of canonical Notch signaling endowed with intrinsic transcription-repressive functions, plays a tumor-promoting function in SCC development. Expression of this gene decreased in upper epidermal layers and human keratinocytes (HKCs) undergoing differentiation, while it increased in premalignant and malignant SCC lesions from skin, head/neck, and lung. Increased CSL levels enhanced the proliferative potential of HKCs and SCC cells, while silencing of CSL induced growth arrest and apoptosis. In vivo, SCC cells with increased CSL levels gave rise to rapidly expanding tumors, while cells with silenced CSL formed smaller and more differentiated tumors with enhanced inflammatory infiltrate. Global transcriptomic analysis of HKCs and SCC cells with silenced CSL revealed major modulation of apoptotic, cell-cycle, and proinflammatory genes. We also show that the histone demethylase KDM6B is a direct CSL-negative target, with inverse roles of CSL in HKC and SCC proliferative capacity, tumorigenesis, and tumor-associated inflammatory reaction. CSL/KDM6B protein expression could be used as a biomarker of SCC development and indicator of cancer treatment.

Authors

Dania Al Labban, Seung-Hee Jo, Paola Ostano, Chiara Saglietti, Massimo Bongiovanni, Renato Panizzon, G. Paolo Dotto

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Figure 8

Effect of CSL modulation on inflammatory cytokines in vivo.

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Effect of CSL modulation on inflammatory cytokines in vivo. (A) SCC13 an...
(A) SCC13 and SCCO28 cells infected with CSL-silencing lentivirus versus empty vector control were injected into backs of NOD/SCID mice. Shown are a representative image of 1 mouse (left panel) and nodule volumes at weeks 1 and 2 after injection (right panel). (B) Representative images of nodule sections processed for fluorescence-guided LCM utilizing anti–pan-keratin–Alexa Fluor 488–conjugated antibody. Shown is a stained section before UV cutting (upper panel) and captured material on an LCM cap after UV cutting (lower panel). Scale bars: 150 μm (upper panel); 500 μm (lower panel). (C) RNA samples from LCM-captured material were examined by RT-qPCR for cytokine marker expression. n = 4 mice for SCC13 at week 1; n = 5 mice for SCC13 at week 2; n = 5 mice for SCCO28 at week 1; n = 4 mice for SCCO28 at week 2. (D) SCC13 cells stably infected with lentiviral vector for doxycycline-inducible Myc-tagged CSL or empty vector control (pIND20) were injected into backs of NOD/SCID mice. Shown is a representative image of 1 mouse (left panel) and nodule volumes at weeks 1 and 2 after injection (right panel). (E) RNA samples from LCM-captured material were examined by RT-qPCR for cytokine marker expression. n = 5 mice at week 1; n = 5 mice at week 2. (C and E) Data are shown as mean ± SEM. *P < 0.1; ***P < 0.001, 1-tailed 1-sample t test followed by Benjamini-Hochberg correction.