Takuya Nakamura

Clinical significance of CYLD downregulation in breast cancer

Abstract Cylindromatosis (CYLD) is a tumor suppressor gene that is mutated in familial cylindromatosis, a rare autosomal dominant disorder associated with numerous benign skin adnexal tumors. CYLD is now known to regulate various signaling pathways, including transforming growth factor-β signaling, Wnt/β-catenin signaling, and NF-κB signaling by deubiquitinating upstream regulatory factors. Downregulation of CYLD has been reported in several malignancies; however, the clinical significance of CYLD expression in many malignancies, including breast cancer, remains to be elucidated. This study investigated the clinical significance of CYLD in breast cancer and its roles in tumor progression. We evaluated CYLD expression in matched normal breast tissue samples and tumor breast tissue samples from 26 patients with breast cancer and in a series of breast cancer cell lines. In addition, by means of immunohistochemistry, we investigated CYLD protein expression and its clinical significance in 244 breast cancer cases. We also analyzed the effects of CYLD repression or overexpression on breast cancer cell viability, cell migration, and NF-κB activity with or without receptor activator of NF-κB ligand (RANKL) stimulation. Breast cancer tissues demonstrated significantly reduced CYLD mRNA expression compared with normal breast tissues. Downregulation of CYLD promoted cell survival and migratory activities through NF-κB activation, whereas CYLD overexpression inhibited those activities in MDA-MB-231 cells. As an important finding, CYLD overexpression also inhibited RANKL-induced NF-κB activation. Our immunohistochemical analysis revealed that reduced CYLD protein expression was significantly correlated with estrogen receptor negativity, high Ki-67 index, high nuclear grade, decreased disease-free survival, and reduced breast cancer-specific survival in primary breast cancer. Moreover, reduced CYLD expression was an independent factor for poor prognosis in breast cancer. CYLD downregulation may promote breast cancer metastasis via NF-κB activation, including RANKL signaling.

Stromal expression of neutrophil gelatinase-associated lipocalin correlates with poor differentiation and adverse prognosis in oral squamous cell carcinoma

Neutrophil gelatinase‐associated lipocalin (NGAL) is a member of the lipocalin superfamily. Although its overexpression in various cancers has been reported, little is known about its expression and clinical significance in oral squamous cell carcinoma (OSCC). This study aimed to elucidate the clinical significance of NGAL in OSCC.

Predictive value of the combination of SMAD4 expression and lymphocyte infiltration in malignant transformation of oral leukoplakia

Oral leukoplakia (OL) is a common, potentially malignant disorder of the oral cavity. SMAD4 was initially identified as a tumor suppressor and central mediator of transforming growth factor (TGF)‐β signaling. In this study, we aimed to determine the expression patterns of SMAD4 in OL, its relationship with the degree of inflammation, and its clinical implications as a biomarker for OL malignant transformation. A total of 150 patients with OL were enrolled in this study. Paraffin‐embedded sections obtained from biopsy or resection specimens were subjected to immunohistochemical analysis. Associations among the status of epithelial SMAD4 expression, stromal lymphocyte infiltration, and malignant transformation of OL were examined. Malignant transformation was significantly associated with the status of SMAD4 expression (P = 0.0017) and lymphocyte infiltration status (P = 0.0054). Cox regression analysis, based on the event‐free survival (EFS), revealed that a low SMAD4 expression was a significant prognostic factor in OL patients (hazard ratio, 2.632; P = 0.043). In addition, a low SMAD4 expression was closely correlated with high lymphocyte infiltration (P = 0.00035), resulting in a significant correlation between the combination of low SMAD4 expression and high lymphocyte infiltration with malignant transformation of OL (P = 0.00027). The combination of the status of epithelial SMAD4 expression and stromal lymphocyte infiltration may be a useful biomarker for predicting malignant transformation in OL patients. These results suggest that not only epithelial SMAD4 loss, but also stromal features, may regulate the risk of malignant transformation of OL.

Osteopontin‐integrin αvβ3 axis is crucial for 5‐fluorouracil resistance in oral squamous cell carcinoma

Clinical applications of a chemotherapeutic agent, 5‐fluorouracil (5‐FU) in oral squamous cell carcinoma (OSCC) have been limited because of drug resistance. This study aimed to identify novel mechanisms of 5‐FU resistance. Here we found increased osteopontin (OPN) gene expression in OSCC tissues with resistance to 5‐FU‐based chemoradiotherapy. OPN overexpression in OSCC cells led to 5‐FU resistance and abrogated the prosurvival effect of the drug in a mouse xenograft model. OPN‐induced 5‐FU resistance required integrin αvβ3. Targeting integrin αvβ3 reversed the resistance in a 5‐FU‐resistant clone highly expressing OPN. Our data suggest that the OPN‐integrin αvβ3 axis is crucial for 5‐FU resistance in OSCC.

Abstract 16: Downregulation of CYLD leads to acquisition of mesenchymal state and increased migration via ligand-independent TGFβR1 activation in human oral squamous cell carcinoma cells

The 5-year survival of patients with oral squamous cell carcinoma (OSCC) has not changed apparently for the past 30 years. Although cylindromatosis (CYLD) is thought as a potent tumor suppressor, its biological significances in malignancies are largely unknown. The aim of this study was to clarify the role of CYLD in OSCC progression. We investigated expression of CYLD in OSCC including intraepithelial neoplasia (IEN; n = 48) and invasive carcinomas (n = 133) tissues and normal oral mucosal tissues (n = 35) by immunohistochemistry. In addition, effects of CYLD knockdown by siRNA transfection on OSCC progression using 5 OSCC cell lines (SAS, Tu4, HSC3, Ca9-22, and SCC-NA) and HaCaT keratinocytes. Our immunohistochemical analyses revealed that CYLD expression was significantly reduced at invasive lesions in OSCC tissues whereas it was conserved in normal epithelium and IEN. In addition, lower CYLD expression was associated with the correlation with the increased tumor size, advanced clinical stage, and poor overall survival in invasive OSCC. Accordingly, CYLD knockdown led to acquisition of mesenchymal state and increased migratory activity in all the OSCC cell lines as well as HaCaT keratinocytes. Notably, such EMT-like changes were completely blocked by a TGFβR1 inhibitor in all the OSCC cell lines, but not in HaCaT keratinocytes. Furthermore, treatment with excess amount of anti-TGFβ antibody (1D11) did not inhibit the EMT-like changes induced by CYLD repression. These findings suggest that downregulation of CYLD promotes invasion through EMT-like changes via ligand-independent TGFβR1 activation in OSCC cells in mechanisms distinct from normal epithelium. Further studies for these mechanisms probably provide new insights into the biology including “TGFβ switch” and development of a novel therapy in OSCC. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 16. doi:1538-7445.AM2012-16

Loss of CYLD promotes cell invasion via ALK5 stabilization in oral squamous cell carcinoma: Association of CYLD with OSCC-related invasion

Oral squamous cell carcinoma (OSCC) has a very poor prognosis because of its highly invasive nature, and the 5‐year survival rate has not changed appreciably for the past 30 years. Although cylindromatosis (CYLD), a deubiquitinating enzyme, is thought to be a potent tumour suppressor, its biological and clinical significance in OSCC is largely unknown. This study aimed to clarify the roles of CYLD in OSCC progression. Our immunohistochemical analyses revealed significantly reduced CYLD expression in invasive areas in OSCC tissues, whereas CYLD expression was conserved in normal epithelium and carcinoma in situ. Furthermore, downregulation of CYLD by siRNA led to the acquisition of mesenchymal features and increased migratory and invasive properties in OSCC cells and HaCaT keratinocytes. It is interesting that CYLD knockdown promoted transforming growth factor‐β (TGF‐β) signalling by inducing stabilization of TGF‐β receptor I (ALK5) in a cell autonomous fashion. In addition, the response to exogenous TGF‐β stimulation was enhanced by CYLD downregulation. The invasive phenotypes induced by CYLD knockdown were completely blocked by an ALK5 inhibitor. In addition, lower expression of CYLD was significantly associated with the clinical features of deep invasion and poor overall survival, and also with increased phosphorylation of Smad3, which is an indicator of activation of TGF‐β signalling in invasive OSCC. These findings suggest that downregulation of CYLD promotes invasion with mesenchymal transition via ALK5 stabilization in OSCC cells. Copyright

Abstract 1859: CYLD downregulation induces aerobic glycolysis in human oral squamous cell carcinoma cells.

Purpose: The hypermetabolic nature of cancer cells, especially their increased reliance on aerobic glycolysis which has been associated with more aggressive phenotype, is considered metabolic hallmarks of cancer cells including oral squamous cell carcinoma (OSCC) cells. However, its precise mechanisms remain unknown. Cylindromatosis (CYLD) is recognized as a tumor suppressor gene whereas little is available about its impact on cancer progression. Our unpublished data showed that lower CYLD expression was associated with poor prognosis in OSCC patients. The objective of our study was to address specific contributions of CYLD to the signature metabolic features of OSCC cells. Materials and methods: We determined the level of glucose consumption as well as lactate production to evaluate the effects of CYLD knockdown by siRNA on aerobic glycolysis in human OSCC cell lines. In addition, we measured extracellular acidification and oxygen consumption rates in OSCC cells by using XF Extracellular Flux Analyzers. Results: Downregulation of CYLD significantly suppressed cell proliferation through cell cycle arrest while it inhibited apoptosis induced by serum withdrawal in vitro. In addition, loss of CYLD led to the increase in both of glucose consumption and lactate production in several OSCC cell lines. Consistently, culture medium became more acidic by CYLD nockdown,compared with the control. Furthermore, glycolysis was promoted by CYLD downregulation whereas no significant difference was found in mitochondrial respiration. Conclusions: Dysfunction of CYLD may contribute to aerobic glycolysis without apparent influence on mitochondrial respiration. Further investigation on the advantage of such increased glycolysis and the change in metabolome profiling may lead to development of effective therapeutic strategies for OSCC and other malignancies. Citation Format: Takuya Nakamura, Satoru Shinriki, Mitsuhiro Hayashi. CYLD downregulation induces aerobic glycolysis in human oral squamous cell carcinoma cells. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1859. doi:10.1158/1538-7445.AM2013-1859

Abstract 3466: Reduced expression of CYLD is an independent prognostic factor in breast cancer and confers treatment resistance and migratory activity in vitro.

Background: CYLD was originally identified as a tumor suppressor that is mutated in familial cylindromatosis. CYLD has deubiquitinase activity and can negatively regulate NF-κB pathways. Recent study has revealed that CYLD plays important roles in tumor progression as well as immune response and osteoclastogenesis. CYLD loss of function has been associated with several tumors. Despite the broad relevance of CYLD to various tumors, its clinical and biological significances in breast cancer are still largely unknown. Materials and Methods: We assessed CYLD expression in 171 primary breast cancer tissues by immunohistochemistry and examined the correlations with CYLD expression and clinicopathological factors as well as patients’ prognosis. In addition, we investigated effects of CYLD knockdown by using siRNA on malignant state in breast cancer cell lines. Results: Our immunohistochemical analysis revealed a significant correlation between loss of CYLD expression and poor patients’ disease free survival (log-rank, p = 0.004), particularly in luminal and triple negative breast cancer patients. Multivariate analysis revealed that loss of CYLD expression was an independent poor prognosis factor (Hazard ratio 2.95, 95% CI 1.20 - 7.98, p = 0.02) in addition to hormone receptor expression status. Loss of CYLD expression correlated with high nuclear grade but not hormone and HER2 status. Consistent with our clinical data, repression of CYLD increased CD44 high/ CD24 low cancer stem-like cell population with acquisition of resistance to apoptosis induced by conventional therapy in MDA-MB-231 cells. Moreover, CYLD knockdown promoted migration through downregulation of Maspin which is a potent suppressor of breast cancer metastasis. Conclusions: CYLD expression was an independent prognostic factor in primary breast cancer. Reduced CYLD function may promote breast cancer progression and treatment resistance. Citation Format: Mitsuhiro Hayashi, Satoru Shinriki, Hirofumi Jono, Takuya Nakamura, Jianying Guo, Yutaka Yamamoto, Hirotaka Iwase, Yukio Ando. Reduced expression of CYLD is an independent prognostic factor in breast cancer and confers treatment resistance and migratory activity in vitro . [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 3466. doi:10.1158/1538-7445.AM2013-3466

Abstract 5149: CYLD downregulation induces aerobic glycolysis via mTOR pathway in human oral squamous cell carcinoma cells

Proceedings: AACR 103rd Annual Meeting 2012‐‐ Mar 31‐Apr 4, 2012; Chicago, IL The hypermetabolic nature of cancer cells and their increased reliance on “aerobic glycolysis,” as originally described by Otto Warburg et al, are considered metabolic hallmarks of cancer cells including oral squamous cell carcinoma (OSCC) cells. However, its precise mechanisms remain unknown. Cylindromatosis (CYLD) is recognized as a tumor suppressor gene whereas little is available about its impact on cancer progression. Our unpublished data showed that lower CYLD expression was associated with poor prognosis in OSCC patients. The objective of our study was to address specific contributions of CYLD to the signature metabolic features of cancer cells, including the so-called “Warburg effect”. We investigated effects of CYLD knockdown by siRNA on aerobic glycolysis in human OSCC cell lines. As the result of CYLD knockdown, both glucose consumption and lactate production significantly increased in several OSCC cell lines with increased expression of LDHA which is known to be important for glycolysis. Consistently, culture medium became more acidic after CYLD knockdown compared with the control. Repression of CYLD expression induced Akt phosphorylation. Importantly, the increase in aerobic glycolysis induced by CYLD repression was completely blocked by an mTOR inhibitor, rapamycin as well as a PIK inhibitor, LY294002. Our study indicats that dysfunction of CYLD contributs to the Warburg effect through Akt-mTOR pathway in OSCC. Further investigation on the advantage of such increased glycolysis and the change in metabolome profiling may lead to development of effective therapeutic strategies for OSCC and other malignancies. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 5149. doi:1538-7445.AM2012-5149

Abstract 700: Reduced CYLD expression is an independent prognostic factor in breast cancer: A possible link with RANKL-RANK signaling

Proceedings: AACR 103rd Annual Meeting 2012‐‐ Mar 31‐Apr 4, 2012; Chicago, IL Background: Deubiquitinase CYLD plays an important role in tumorigenesis and immune response. RANKL-RANK system is required for osteoclast development and is also involved in bone metastasis in various malignancies while it has been also implicated in tumorigenesis, metastasis to distant organs other than bone in breast cancer through unknown mechanisms. Importantly, a recent study has reported that CYLD negatively regulated RANKL-RANK signaling in osteoclastogenesis. However, not only the role of CYLD but also its involvement in RANKL-RANK signaling in breast cancer is largely unknown. The purpose of this study was to elucidate clinical and biological significance of CYLD as well as its association with RANKL-RANK signaling in breast cancer. Materials and Methods: We assessed CYLD mRNA expression in 305 primary invasive breast cancer tissues including 26 matched-pair of tumoral and adjacent non-tumoral tissues, and 9 breast cancer cell lines as well as a nonmalignant breast epithelial cell line, HMEC by quantitative real-time RT-PCR. In addition, effect of CYLD knockdown by using siRNA on cell proliferation, migratory activity and the biological activity of RANKL in MDA-MB-231 cells. Results: Expression levels of CYLD mRNA were lower in tumoral lesion than the matched non-tumoral lesion in all of 26 cases. Our statistical analysis revealed that lower CYLD mRNA expression was significantly associated with reduced disease free survival rate (rog-rank, p = 0.025), irrespectively of breast cancer subtype. Multivariate analyses for disease free survival confirmed that low CYLD mRNA expression (Hazard ratio: HR 2.23, 95% CI 1.09 - 4.36, p = 0.029) in addition to estrogen receptor status (HR 0.15, 95% CI 0.05 - 0.44, p = 0.0003) and lymph node metastasis (HR 2.21, 95% CI 1.10 - 4.62, p = 0.026) were significant factors. Consistent with our clinical data, CYLD gene expression was reduced in all the breast cancer cell lines compared with HMEC cells. Repression of CYLD gene expression led to increased cell number in MDA-MB-231 cells. Interestingly, combination of CYLD knockdown and RANKL stimulation promoted cell migration while no change was observed in the setting of each alone. Conclusion: Downregulation of CYLD was common and an independent poor prognostic factor in invasive breast cancer. CYLD repression may promote breast cancer development and/ or progression in coordination with RANKL-RANK signaling. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 700. doi:1538-7445.AM2012-700