DeltaNp63 versatilely regulates a Broad NF-kappaB gene program and promotes squamous epithelial proliferation, migration, and inflammation

Head and neck squamous cell carcinoma (HNSCC) and many other epithelial malignancies exhibit increased proliferation, invasion, and inflammation, concomitant with aberrant nuclear activation of TP53 and NF-κB family members ΔNp63, cRel, and RelA. However, the mechanisms of cross-talk by which these transcription factors coordinate gene expression and the malignant phenotype remain elusive. In this study, we showed that ΔNp63 regulates a cohort of genes involved in cell growth, survival, adhesion, and inflammation, which substantially overlaps with the NF-κB transcriptome. ΔNp63 with cRel and/or RelA are recruited to form novel binding complexes on p63 or NF-κB/Rel sites of multitarget gene promoters. Overexpressed ΔNp63- or TNF-α-induced NF-κB and inflammatory cytokine interleukin-8 (IL-8) reporter activation depended on RelA/cRel regulatory binding sites. Depletion of RelA or ΔNp63 by small interfering RNA (siRNA) significantly inhibited NF-κB-specific, or TNF-α-induced IL-8 reporter activation. ΔNp63 siRNA significantly inhibited proliferation, survival, and migration by HNSCC cells in vitro. Consistent with these data, an increase in nuclear ΔNp63, accompanied by increased proliferation (Ki-67) and adhesion (β4 integrin) markers, and induced inflammatory cell infiltration was observed throughout HNSCC specimens, when compared with the basilar pattern of protein expression and minimal inflammation seen in nonmalignant mucosa. Furthermore, overexpression of ΔNp63α in squamous epithelial cells in transgenic mice leads to increased suprabasilar cRel, Ki-67, and cytokine expression, together with epidermal hyperplasia and diffuse inflammation, similar to HNSCC. Our study reveals ΔNp63 as a master transcription factor that, in coordination with NF-κB/Rels, orchestrates a broad gene program promoting epidermal hyperplasia, inflammation, and the malignant phenotype of HNSCC.link_to_OA_fulltex

YAP dysregulation by phosphorylation or Δnp63-mediated gene repression promotes proliferation, survival and migration in head and neck cancer subsets

Overexpression of the Yes-associated protein (YAP), and TP53 family members ΔNp63 and p73, have been independently detected in subsets of head and neck squamous cell carcinomas (HNSCCs). YAP may serve as a nuclear cofactor with ΔNp63 and p73, but the functional role of YAP and their potential relationship in HNSCCs are unknown. In this study, we show that in a subset of HNSCC lines and tumors, YAP expression is increased but localized in the cytoplasm in association with increased AKT and YAP phosphorylation, and with decreased expression of ΔNp63 and p73. In another subset, YAP expression is decreased but detectable in the nucleus in association with lower AKT and YAP phosphorylation, and with increased ΔNp63 and p73 expression. Inhibiting AKT decreased serine-127 phosphorylation and enhanced nuclear translocation of YAP. ΔNp63 bound to the YAP promoter and suppressed its expression. Transfection of a YAP-serine-127-alanine phosphoacceptor-site mutant or ΔNp63 knockdown significantly increased nuclear YAP and cell death. Conversely, YAP knockdown enhanced cell proliferation, survival, migration and cisplatin chemoresistance. Thus, YAP function as a tumor suppressor may alternatively be dysregulated by AKT phosphorylation at serine-127 and cytoplasmic sequestration, or by transcriptional repression by ΔNp63, in different subsets of HNSCC. AKT and/or ΔNp63 are potential targets for enhancing YAP-mediated apoptosis and chemosensitivity in HNSCCs. © 2010 Macmillan Publishers Limited All rights reserved

Attenuated transforming growth factor beta signaling promotes nuclear factor-kappaB activation in head and neck cancer

Although constitutively activated nuclear factor-kappaB (NF-kappaB), attenuated transforming growth factor beta (TGFbeta) signaling, and TP53 mutations frequently occur in human cancers, how these pathways interact and together contribute to malignancy remains uncertain. Here, we found an association between overexpression of NF-kappaB-related genes, reduced expression of TGFbeta receptor (TbetaR) subunits and downstream targets, and TP53 genotype in head and neck squamous cell carcinoma (HNSCC). In response to recombinant TGFbeta1, both growth inhibition and TGFbeta target gene modulation were attenuated or absent in a panel of human HNSCC lines. However, in HNSCC cells that retained residual TGFbeta signaling, TGFbeta1 inhibited both constitutive and tumor necrosis factor alpha-stimulated NF-kappaB activity. Furthermore, HNSCC lines overexpressing mutant (mt) TP53 and human tumor specimens with positive TP53 nuclear staining exhibited reduced TbetaRII and knocking down mtTP53 induced TbetaRII, increasing TGFbeta downstream gene expression while inhibiting proinflammatory NF-kappaB target gene expression. Transfection of ectopic TbetaRII directly restored TGFbeta signaling while inhibiting inhibitor kappaBalpha degradation and suppressing serine-536 phosphorylation of NF-kappaB p65 and NF-kappaB transcriptional activation, linking these alterations. Finally, experiments with TbetaRII conditional knockout mice show that abrogation of TGFbeta signaling promotes the sustained induction of NF-kappaB and its proinflammatory target genes during HNSCC tumorigenesis and progression. Together, these findings elucidate a regulatory framework in which attenuated TGFbeta signaling promotes NF-kappaB activation and squamous epithelial malignancy in the setting of altered TP53 status.link_to_OA_fulltex

Correction: Exploration of surgical blood pressure management and expected motor recovery in individuals with traumatic spinal cord injury.

A correction to this paper has been published and can be accessed via a link at the top of the paper

Exploration of surgical blood pressure management and expected motor recovery in individuals with traumatic spinal cord injury.

Study designRetrospective analysis.ObjectiveTo assess the impact of mean arterial blood pressure (MAP) during surgical intervention for spinal cord injury (SCI) on motor recovery.SettingLevel-one Trauma Hospital and Acute Rehabilitation Hospital in San Jose, CA, USA.MethodsTwenty-five individuals with traumatic SCI who received surgical and acute rehabilitation care at a level-one trauma center were included in this study. The Surgical Information System captured intraoperative MAPs on a minute-by-minute basis and exposure was quantified at sequential thresholds from 50 to 104 mmHg. Change in International Standards for Neurological Classification of Spinal Cord Injury (ISNCSCI) motor score was calculated based on physiatry evaluations at the earliest postoperative time and at discharge from acute rehabilitation. Linear regression models were used to estimate the rate of recovery across the entire MAP range.ResultsAn exploratory analysis revealed that increased time within an intraoperative MAP range (70-94 mmHg) was associated with ISNCSCI motor score improvement. A significant regression equation was found for the MAP range 70-94 mmHg (F[1, 23] = 5.07, r2 = 0.181, p = 0.034). ISNCSCI motor scores increased 0.039 for each minute of exposure to the MAP range 70-94 mmHg during the operative procedure; this represents a significant correlation between intraoperative time with MAP 70-94 and subsequent motor recovery. Blood pressure exposures above or below this range did not display a positive association with motor recovery.ConclusionsHypertension as well as hypotension during surgery may impact the trajectory of recovery in individuals with SCI, and there may be a direct relationship between intraoperative MAP and motor recovery

Correction: Exploration of surgical blood pressure management and expected motor recovery in individuals with traumatic spinal cord injury.

An amendment to this paper has been published and can be accessed via a link at the top of the paper

Correction: Exploration of surgical blood pressure management and expected motor recovery in individuals with traumatic spinal cord injury

A correction to this paper has been published and can be accessed via a link at the top of the paper

TAZ Expression as a Prognostic Indicator in Colorectal Cancer

Agency of Science, Technology, and Research (A*STAR), SingaporeThe Hippo pathway restricts the activity of transcriptional coactivators TAZ (WWTR1) and YAP. TAZ and YAP are reported to be overexpressed in various cancers, however, their prognostic significance in colorectal cancers remains unstudied. The expression levels of TAZ and YAP, and their downstream transcriptional targets, AXL and CTGF, were extracted from two independent colon cancer patient datasets available in the Gene Expression Omnibus database, totaling 522 patients. We found that mRNA expressions of both TAZ and YAP were positively correlated with those of AXL and CTGF (p<0.05). High level mRNA expression of TAZ, AXL or CTGF significantly correlated with shorter survival. Importantly, patients co-overexpressing all 3 genes had a significantly shorter survival time, and combinatorial expression of these 3 genes was an independent predictor for survival. The downstream target genes for TAZ-AXL-CTGF overexpression were identified by Java application MyStats. Interestingly, genes that are associated with colon cancer progression (ANTXR1, EFEMP2, SULF1, TAGLN, VCAN, ZEB1 and ZEB2) were upregulated in patients co-overexpressing TAZ-AXL-CTGF. This TAZ-AXL-CTGF gene expression signature (GES) was then applied to Connectivity Map to identify small molecules that could potentially be utilized to reverse this GES. Of the top 20 small molecules identified by connectivity map, amiloride (a potassium sparing diuretic,) and tretinoin (all-trans retinoic acid) have shown therapeutic promise in inhibition of colon cancer cell growth. Using MyStats, we found that low level expression of either ANO1 or SQLE were associated with a better prognosis in patients who co-overexpressed TAZ-AXL-CTGF, and that ANO1 was an independent predictor of survival together with TAZ-AXL-CTGF. Finally, we confirmed that TAZ regulates Axl, and plays an important role in clonogenicity and non-adherent growth in vitro and tumor formation in vivo. These data suggest that TAZ could be a therapeutic target for the treatment of colon cancer