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To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.ydbio.2008.08.011 Byline: Yan I. Liu (a), Mikyung V. Chang (a), Hui E. Li (a), Scott Barolo (b), Jinhee L. Chang (a), Tim A. Blauwkamp (a), Ken M. Cadigan (a) Keywords: ACF1; Chromatin; ISWI; TCF; Wingless Abstract: The highly conserved Wingless/Wnt signaling pathway controls many developmental processes by regulating the expression of target genes, most often through members of the TCF family of DNA-binding proteins. In the absence of signaling, many of these targets are silenced, by mechanisms involving TCFs that are not fully understood. Here we report that the chromatin remodeling proteins ISWI and ACF1 are required for basal repression of WG target genes in Drosophila. This regulation is not due to global repression by ISWI and ACF1 and is distinct from their previously reported role in chromatin assembly. While ISWI is localized to the same regions of Wingless target gene chromatin as TCF, we find that ACF1 binds much more broadly to target loci. This broad distribution of ACF1 is dependent on ISWI. ISWI and ACF1 are required for TCF binding to chromatin, while a TCF-independent role of ISWI-ACF1 in repression of Wingless targets is also observed. Finally, we show that Wingless signaling reduces ACF1 binding to WG targets, and ISWI and ACF1 regulate repression by antagonizing histone H4 acetylation. Our results argue that WG signaling activates target gene expression partly by overcoming the chromatin barrier maintained by ISWI and ACF1. Author Affiliation: (a) Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, Michigan 48109-1048, USA (b) Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, Michigan 48109, USA Article History: Received 23 March 2008; Revised 1 August 2008; Accepted 9 August 2008

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.ydbio.2008.05.551 Byline: Jinhee L. Chang (a), Mikyung V. Chang (a), Scott Barolo (b), Ken M. Cadigan (a) Keywords: Naked cuticle; Feedback antagonist; Wnt; TCF; Wingless Abstract: Signaling pathways usually activate transcriptional targets in a cell type-specific manner. Notable exceptions are pathway-specific feedback antagonists, which serve to restrict the range or duration of the signal. These factors are often activated by their respective pathways in a broad array of cell types. For example, the Wnt ligand Wingless (Wg) activates the naked cuticle (nkd) gene in all tissues examined throughout Drosophila development. How does the nkd gene respond in such an unrestricted manner to Wg signaling? Analysis in cell culture revealed regions of the nkd locus that contain Wg response elements (WREs) that are directly activated by the pathway via the transcription factor TCF. In flies, Wg signaling activates these WREs in multiple tissues, in distinct but overlapping patterns. These WREs are necessary and largely sufficient for nkd expression in late stage larval tissues, but only contribute to part of the embryonic expression pattern of nkd. These results demonstrate that nkd responsiveness to Wg signaling is achieved by several WREs which are broadly (but not universally) activated by the pathway. The existence of several WREs in the nkd locus may have been necessary to allow the Wg signaling-Nkd feedback circuit to remain intact as Wg expression diversified during animal evolution. Author Affiliation: (a) Department of Molecular, Cellular and Developmental Biology, University of Michigan, 830 N. University Avenue Ann Arbor MI 48109-1048, USA (b) Department of Cell and Developmental Biology, University of Michigan Medical School, 109 Zina Pitcher Place, Ann Arbor, MI 48109-2200, USA Article History: Received 8 April 2008; Revised 24 May 2008; Accepted 27 May 2008

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.ydbio.2007.11.023 Byline: Jinhee L. Chang, Hua V. Lin, Timothy A. Blauwkamp, Ken M. Cadigan Keywords: Drosophila; Wingless; Wnt; Split ends; Spenito; SHARP; Mint; OTT; RBM-15 Abstract: Wingless (Wg)/Wnt signaling directs a variety of cellular processes during animal development by promoting the association of Armadillo/[beta]-catenin with TCFs on Wg-regulated enhancers (WREs). Split ends (Spen), a nuclear protein containing RNA recognition motifs (RRMs) and a SPOC domain, is required for optimal Wg signaling in several fly tissues. In this report, we demonstrate that Spenito (Nito), the only other fly protein containing RRMs and a SPOC domain, acts together with Spen to positively regulate Wg signaling. The partial defect in Wg signaling observed with spen RNAi was enhanced by simultaneous knockdown of nito while it was rescued by expression of nito in wing imaginal discs. In cell culture, depletion of both factors causes a greater defect in the activation of several Wg targets than RNAi of either spen or nito alone. These nuclear proteins are not required for Armadillo stabilization or the recruitment of TCF and Armadillo to a WRE. Loss of Wg target gene activation in cells depleted for spen and nito was not dependent on the transcriptional repressor Yan or Suppressor of Hairless, two previously identified targets of Spen. We propose that Spen and Nito act redundantly downstream of TCF/Armadillo to activate many Wg transcriptional targets. Author Affiliation: Department of Molecular, Cellular and Developmental Biology, University of Michigan, Natural Science Building, Ann Arbor, MI 48109-1048, USA Article History: Received 29 June 2007; Revised 10 November 2007; Accepted 12 November 2007

Most patients with lung squamous cell carcinoma (LSCC) undergo chemotherapy, radiotherapy, and adjuvant immunotherapy for locally advanced disease. The efficacy of these treatments is still limited because of dose-limiting toxicity or locoregional recurrence. New combination approaches and targets such as actionable oncogenic drivers are needed to advance treatment options for patients with LSCC. Moreover, other options for chemotherapy-ineligible patients are limited. As such, there is a critical need for the development of selective and potent chemoradiosensitizers for locally advanced LSCC. In this study, we investigated inhibiting TRAF2- and NCK-interacting protein kinase (TNIK), which is amplified in 40% of patients with LSCC, as a strategy to sensitize LSCC tumors to chemotherapy and radiotherapy. Employing a range of human LSCC cell lines and the TNIK inhibitor NCB-0846, we investigated the potential of TNIK as a chemo- and radiosensitizing target with in vitro and in vivo preclinical models. The combination of NCB-0846 with cisplatin or etoposide was at best additive. Interestingly, pre-treating LSCC cells with NCB-0846 prior to ionizing radiation (IR) potentiated the cytotoxicity of IR in a TNIK-specific fashion. Characterization of the radiosensitization mechanism suggested that TNIK inhibition may impair the DNA damage response and promote mitotic catastrophe in irradiated cells. In a subcutaneous xenograft in vivo model, pretreatment with NCB-0846 significantly enhanced the efficacy of IR and caused elevated necrosis in TNIKhigh LK2 tumors but not TNIKlow KNS62 tumors. Overall, these results indicate that TNIK inhibition may be a promising strategy to increase the efficacy of radiotherapy in patients with LSCC with high TNIK expression., (©2024 The Authors; Published by the American Association for Cancer Research.)