LncRNA HOTAIR promotes the invasion and metastasis of oral squamous cell carcinoma through metastasis-associated gene 2

Despite therapeutic advancements, there has been little improvement in the survival status of patients with oral squamous cell carcinoma (OSCC). HOX antisense intergenic RNA (HOTAIR) has been shown to be dysregulated in several cancer types. However, the roles of HOTAIR in OSCC remain largely unknown. In this study, we investigated the association of HOTAIR expression with clinicopathological features in OSCC patients and the crucial roles of HOTAIR in the modulation of tumor progression. Our results showed that HOTAIR was highly expressed both in OSCC tissue samples and cell lines compared with corresponding normal oral mucosa tissues and human oral keratinocytes. Its overexpression was positively correlated with TNM (tumor-node-metastases) stage, histological grade, and regional lymph node metastasis. The knockdown of HOTAIR by short hairpin RNA significantly decreased the migration, invasion, and epithelial-mesenchymal transition of OSCC cells in vitro. Moreover, there was a negative correlation between HOTAIR and microRNA-326 expression in OSCC tissue samples and cell lines. Luciferase reporter and loss-of-function assays revealed that HOTAIR acted as a competitive endogenous RNA effectively sponging miR-326, thereby regulating the derepression of metastasis-associated gene 2 (MTA2). Finally, the expression and clinical significance of MTA2 were analyzed in another cohort of OSCC tissue samples. High MTA2 expression was significantly correlated with clinicopathological features of advanced OSCC and poor prognosis for patients with OSCC. Collectively, HOTAIR overexpression promoted the progression of OSCC. The HOTAIR–miR-326-MTA2 axis may contribute to a better understanding of OSCC pathogenesis and be a potential therapeutic target for OSCC.     

miR-451下调MIF的表达并抑制其促鼻咽癌细胞浸润和转移的作用

目的:研究巨噬细胞移动抑制因子(macrophage migration inhibitory factor,MIF)在鼻咽癌细胞浸润转移过程中的作用.方法:采用免疫印迹实验观察鼻咽癌细胞株HONE1、5-8F、CNE-1、CNE-2中MIF的表达水平.检验过表达MIF后鼻咽癌细胞株HONE1中黏附蛋白的表达水平以及miR-451对5-8F和293A细胞中MIF表达水平的影响,Transwell实验观察鼻咽癌细胞侵袭迁移能力,荧光报告系统验证miR-451对MIF的调控作用.结果:MIF在鼻咽癌高转移细胞株5-8F中表达量增高,MIF通过降低黏附蛋白的表达,减弱鼻咽癌细胞间黏附性,提高鼻咽癌细胞侵袭迁移能力.MIF的表达受miR-451的调控,miR-451能够抑制MIF的表达.结论:MIF能降低鼻咽癌细胞间的黏附性,在鼻咽癌的浸润转移过程中具有重要的促进作用,并且MIF的表达受miR-451的直接调控.     

Macrophage migration inhibitory factor: roles in regulating tumor cell migration and expression of angiogenic factors in hepatocellular carcinoma

Macrophage migration inhibitory factor (MIF) may contribute to multiple aspects of tumor progression, including control of cell proliferation, differentiation, cell survival and angiogenesis. However, the potential roles of MIF in regulating hepatocellular carcinoma (HCC) tumor cell migration and the expression of angiogenic factors by HCC tumor cells have not been studied yet. In our study, we reported that intracellular MIF mRNA and protein were overexpressed in HCC tissues compared to nontumor tissues by using in situ hybridization and immunohistochemic staining. HCC tumor cell lines also secreted large amounts of MIF into the supernatants of tumor cell culture. To assess the role of MIF in HCC, we employed the transwell invasion chamber to study the effect of MIF on tumor cell migration. Our results showed that recombinant MIF and the supernatants of tumor cell line culture could enhance the invasion and migration of HCC cells. This effect can be inhibited by the addition of a neutralizing anti-MIF antibody. We observed that increased MIF serum levels correlated with higher levels of interleukin-8 (IL-8) in the sera of patients with HCC than in normal volunteers. We therefore hypothesized that MIF may regulate the production of angiogenic factors by HCC cells. To test this hypothesis, we examined the effect of MIF treatment on vascular endothelial growth factor (VEGF) and IL-8 expression by HCC cell lines. MIF induced a significant dose-dependent increase in IL-8 and VEGF production. Taken together, our results indicated that MIF may act as an autocrine-acting factor that stimulates angiogenesis and metastasis in HCC by promoting expression of angiogenic factors and migration of tumor cells. A more detailed understanding of the MIF regulatory mechanisms involved may provide insight into new direction in the treatment of HCC.     

Heat shock factor 1 in cancer‐associated fibroblasts is a potential prognostic factor and drives progression of oral squamous cell carcinoma

Heat shock factor 1 (HSF1) is highly expressed in various malignancies and is a potential modulator of tumor progression. Emerging evidence suggests that HSF1 activation in stromal cells is closely related to poor patient prognosis. However, the role of HSF1 in oral squamous cell carcinoma (OSCC) remains elusive. We aimed to investigate the function of HSF1 in cancer‐associated fibroblasts (CAFs) of the tumor microenvironment (TME) and in tumor development. In the present study, we found that HSF1 was highly expressed in both CAFs and tumor cells, and was significantly correlated with poor prognosis and overall survival. Moreover, HSF1 overexpression in CAFs resulted in a fibroblast‐like phenotype of Cal27 cells, induced epithelial‐mesenchymal transition (EMT), and promoted proliferation, migration and invasion in Cal27 cells. HSF1 knockdown attenuated features of CAFs and reduced EMT, proliferation, migration and invasion in Cal27 cells. Furthermore, HSF1 in CAFs promoted tumor growth in nude mice. Taken together, these data suggest that HSF1 expression in CAFs drive OSCC progression, and could serve as an independent prognostic marker of patients with OSCC. Thus, HSF1 is a potent mediator of OSCC malignancy.     

Mesenchymal stem cell‐derived CCN2 promotes the proliferation,migration and invasion of human tongue squamous cell carcinoma cells

Recent studies have demonstrated that mesenchymal stem cells (MSC) exhibit a tropism to tumors and form the tumor stroma. In addition, we found that MSC can secrete different types of factors. However, the involvement of MSC‐derived factors in human tongue squamous cell carcinoma (TSCC) growth has not been clearly addressed. The CCN family includes multifunctional signaling molecules that affect the initiation and development events of various tumors. In our study, we report that CCN2/connective tissue growth factor (CTGF) was the most highly induced among the CCN family members in MSC that were co‐cultured with TSCC cells. To evaluate the relationship between CCN2 and TSCC growth, we downregulated MSC‐derived CCN2 expression with shRNA targeting CCN2 and found that MSC‐secreted CCN2 promotes TSCC cell proliferation, migration and invasion. We also confirmed that MSC‐derived CCN2 partially accelerated tumor growth in vitro. Taken together, these results suggest that MSC‐derived CCN2 contributes to the promotion of proliferation, migration and invasion of TSCC cells and may be a possible therapy target in the future.     

Polycomb group protein EZH2‐mediated E‐cadherin repression promotes metastasis of oral tongue squamous cell carcinoma

Enhancer of Zeste homolog 2 (EZH2) is a critical component of the polycomb‐repressive complex 2 (PRC2) that regulates many essential biological processes, including embryogenesis and many developmental events. The oncogenic role of EZH2 has recently been implicated in several cancer types. In this study, we first confirmed that the over‐expression of EZH2 is a frequent event in oral tongue squamous cell carcinoma (OTSCC). We further demonstrated that EZH2 over‐expression is correlated with advanced stages of the disease and is associated with lymph node metastasis. Statistical analysis revealed that EZH2 over‐expression was correlated with reduced overall survival. Furthermore, over‐expression of EZH2 was correlated with reduced expression of tumor suppressor gene E‐cadherin. These observations were confirmed in vitro, in which knockdown of EZH2‐induced E‐cadherin expression and reduced cell migration and invasion. In contrast, ectopic transfection of EZH2 led to reduced E‐cadherin expression and enhanced cell migration and invasion. Furthermore, EZH2 may act on cell migration in part by suppressing the E‐cadherin expression. Taken together, these data suggest that EZH2 plays major roles in the progression of OTSCC, and may serve as a biomarker or therapeutic target for patients at risk of metastasis. © 2011 Wiley Periodicals, Inc.     

miR‐122 promotes metastasis of clear‐cell renal cell carcinoma by downregulating Dicer

Although overall downregulation of microRNAs (miRNAs) is a general feature of clear‐cell renal cell carcinoma (ccRCC), several miRNAs are consistently upregulated, among which miR‐122 was markedly increased in ccRCC tissues. Our study aims to determine the functional importance and underlying mechanism of miR‐122 in ccRCC metastasis. Here, we demonstrate that the expression of miR‐122 increased in ccRCC tissues, and higher miR‐122 expression was found in ccRCC tissues with metastatic disease than in those without metastasis. The increased miR‐122 levels were associated with poor metastasis‐free survival in ccRCC patients with localized disease. Dicer was validated as a direct functional target of miR‐122. Overexpression of miR‐122 promoted migration and invasion of ccRCC cells in vitro and metastatic behavior of ccRCC cells in vivo. Inhibition of miR‐122 attenuated this metastatic phenotype in vitro. Importantly, miR‐122 exerted its pro‐metastatic properties in ccRCC cells by downregulating Dicer and its downstream effector, the miR‐200 family, thereby inducing epithelial–mesenchymal transition (EMT). Our results suggest an important role of the miR‐122/Dicer/miR‐200s/EMT pathway in ccRCC metastasis. Furthermore, miR‐122 may serve as a biomarker for discriminating ccRCC with metastatic potential.     

miRNA control of tumor cell invasion and metastasis

MicroRNAs have emerged as a novel class of noncoding RNAs that regulate gene expression at the post‐translational level in almost every biological event. A large body of evidence indicates that microRNAs regulate the expression of different genes that play an important role in cancer cell invasion, migration and metastasis. In this review, we briefly describe the role of various miRNAs in invasion, migration and metastasis which are essential steps during cancer progression.     

RACK1对食管鳞癌细胞侵袭转移能力的抑制作用

目的:探讨RACK1表达水平与食管鳞状细胞癌不同转移潜能细胞侵袭转移能力的关系.方法:Transwell实验检测食管鳞癌EC9706-H、EC9706-L和EC109-H、EC109-L细胞的转移潜能;利用RT-PCR和Western blot方法,检测食管鳞癌高低转移细胞系EC9706-H、EC9706-L和EC109-H、EC109-L中RACK1的mRNA和蛋白表达水平.利用慢病毒转染技术上调RACK1低表达细胞中RACK1的表达后,采用Transwell实验检测其侵袭和迁移能力的变化.结果:EC9706-H细胞和EC109-H细胞的体外侵袭和迁移能力显著高于EC9706-L和EC109-L细胞系.RT-PCR和Western blot实验结果显示,RACK1在EC9706-H细胞和EC109-H细胞中呈低表达;而在EC9706-L细胞和EC109-L细胞中呈高表达.通过慢病毒转染技术上调EC9706-H和EC109-H细胞系中RACK1的表达,二者的侵袭转移能力明显降低.结论:RACK1表达水平与食管鳞癌细胞的侵袭转移能力负相关,过表达RACK1能够抑制食管鳞癌细胞的侵袭转移能力.这提示,RACK1在食管鳞癌的侵袭转移中发挥重要作用,有可能成为其诊断、治疗及预后评估的新靶点.     

上皮间充质转化对肺鳞状细胞癌侵袭和迁移能力的影响*

目的：研究肺鳞状细胞癌（lung squamous cell carcinoma ,LSCC）上皮间充质转化（epithelial-to-mesenchymal transition ,EMT ）的临床意义,并阐述EMT 对肺鳞癌侵袭转移能力的影响。方法：对79例肺鳞癌组织切片进行E-cadherin 、Vimentin 及TGF-β 1 的免疫组织化学染色,分析其临床意义。将肺鳞癌细胞系SK-MES-1 于含有不同浓度转化生长因子- β 1（transforming growth factor,TGF-β 1）的培养基中,分别诱导培养5、10d 后,利用Western blot、RT-PCR 检测E-cadherin 、Vimentin 的表达变化,以划痕、侵袭实验来判断不同浓度、诱导时间对SK-MES-1 细胞功能的影响。结果：肺鳞癌发生淋巴转移病例中E-cadherin 表达较未发生淋巴转移者低,而Vimentin 表达则高于未发生淋巴转移的病例,差异具有统计学意义（P < 0.05）。 TGF-β 1 阳性表达与淋巴结转移相关,差异具有统计学意义（P < 0.05）。 Western blot和RT-PCR 显示10ng/mL TGF-β 1 诱导培养的SK-MES-1 细胞中,Vi ?mentin 表达增强明显,E-cadherin 表达减弱。细胞划痕和侵袭实验结果表明SK-MES-1 经诱导后,迁移和体外侵袭能力增强。结论：肺鳞癌的淋巴转移与上皮间充质转化有关,TGF-β 1 可诱导肺鳞癌细胞发生EMT ,增强其侵袭和迁移的能力。     

MIIP对肾癌细胞增殖、侵袭及迁移能力的影响

目的:利用质粒转染技术制备过表达迁移侵袭抑制蛋白(migration and invasion inhibitory protein,MIIP)的肾癌786-0/MIIP细胞系,观察MIIP对细胞增殖、侵袭及迁移能力的影响.方法:构建携带MIIP基因的质粒,通过脂质体质粒转染技术上调肾癌786-0细胞系MIIP基因表达.Western-blot、Real-time PCR检测转染效果;利用MTT实验检测MIIP对786-0细胞增殖能力的影响;Transwell实验、划痕实验检测MIIP对786-0细胞侵袭、迁移能力的影响.结果:Westem-blot、Real-time PCR检测发现实验组786-0/MIIP细胞MIIP蛋白及mRNA表达量有效上调.MTT实验显实验组786-0/MIIP细胞增殖能力明显减弱(P＜0.01).Transwell实验显实验组786-0/MIIP细胞侵袭能力减弱,穿透小室细胞数明显减少(P＜0.01).细胞划痕实验显实验组786-0/MIIP细胞迁移能力显著下降(P＜0.01).结论:通过质粒转染技术能够制备过表达MIIP的肾癌细胞系.转染成功的肾癌786-0/MIIP细胞系MIIP表达量增加,有效抑制了肾癌细胞的增殖、侵袭与迁移.     

Effect of verbascoside on apoptosis and metastasis in human oral squamous cell carcinoma

Despite significant advances in therapy, the 5‐year survival rates for patients with advanced stage oral cancers still remains poor as an appropriate treatment has not been found yet, due to side effects of chemo/radiotherapy. Verbascoside (VB), a major bioactive constituent of the Tsoong herb, displays pharmacological properties by exhibiting anti‐oxidative, anti‐inflammatory and anti‐cancer activities. However, the underlining function and mechanism of VB in human oral squamous cell carcinoma (OSCC) remains unclear. In this study, we show that VB significantly decreased the viability and metastasis of HN4 and HN6 tumor cells, while promoting apoptosis. A xenograft OSCC mouse model further showed that intraperitoneal injection of VB strongly inhibited growth and lung metastasis of implanted tumor cells. Immunoblot analysis confirmed that VB effectively suppressed nuclear factor (NF)‐κB activation and downstream Bcl‐2/Bcl‐XL expression, resulting in increased OSCC cell apoptosis. In addition, VB suppressed mRNA and protein expression of matrix metalloproteinase‐9 via suppression of NF‐κB activation, thereby inhibiting tumor cell metastasis. Inspiringly, compared to cisplatin‐treated group, VB is a biocompatible agent without signficant side effects in vivo. Collectively, our results demonstrate that VB effectively inhibits OSCC tumor cell growth and metastasis via suppression of IκB kinase complex (IKK)/NF‐κB‐related signaling activation, suggesting that VB has potential use as a potent anticancer agent in OSCC therapeutic strategies.     

Podoplanin promotes the invasion of oral squamous cell carcinoma in coordination with MT1-MMP and Rho GTPases

Podoplanin overexpression has been reported in various cancers, however, the precise mechanism for podoplanin to promote tumor progression remains elusive. In the present study, podoplanin overexpression was found associated with invasiveness both in OSCC tissues and cell lines. Moreover, the cell invasiveness increased with forced podoplanin expression and decreased when podoplanin was knockdown, indicating podoplanin-mediated cell invasion during OSCC progression. To further identify the role of podoplanin in tumor invasion, cell spreading and immunofluorescence assay were performed firstly. It was found that podoplanin knockdown caused an impaired cell spreading with reduced filopodia and the premature assembly of stress fibers while podoplanin overexpression induced an increase in cellular protrusions and stress fibers with extensive parallel bundles. Then, pull-down assays revealed forced podoplanin expression increased Cdc42 activity and reduced RhoA activity while podoplanin knockdown decreased Cdc42 and increased RhoA markedly. Moreover, a hierarchy of crosstalk between RhoA and Cdc42 was confirmed in podoplanin-mediated cell motility. On the other hand, a significant correlation between podoplanin and MT1-MMP expression in OSCCs was found both in vivo and in vitro, co-located in invasive cells and cellular protrusions. Furthermore, our data showed MT1-MMP knockdown significantly blocked the upregulation of cell motility by forced podoplanin expression, indicating that MT1-MMP played a role in podoplanin-mediated tumor invasion. To further confirm the interaction between RhoA/Cdc42 complex, MT1-MMP and podoplanin, co-precipitation experiments were performed. Both the co-precipitation of podoplanin with MT1-MMP and the podoplanin-induced specific binding of MT1-MMP to Cdc42 were found, and immunofluorescence revealed the co-location of podoplanin, MT1-MMP and Cdc42 at the plasma membrane and filopodia induced an increase in cellular protrusion and stress fibers formation. Moreover, MT1-MMP inhibition could partly rescue the increase of Cdc42 activity caused by forced podoplanin expression. Taken together, our data demonstrated a hierarchy of crosstalk between RhoA and Cdc42 was involved in podoplanin-mediated cytoskeleton remodeling and invasion; the co-location and co-ordination of podoplanin, Cdc42 and MT1-MMP in the invadopodia might induce cytoskeleton remodeling, ECM degradation and tumor invasion, while podoplanin-induced EMT may not be indispensible during OSCC progression.