Expression of KAI1 and tenascin, and microvessel density are closely correlated with liver metastasis of gastrointestinal adenocarcinoma

Tetraspanins: Novel Molecular Regulators of Gastric Cancer

Gastric cancer is the fourth and fifth most common cancer worldwide in men and women, respectively. However, patients with an advanced stage of gastric cancer still have a poor prognosis and low overall survival rate. The tetraspanins belong to a protein superfamily with four hydrophobic transmembrane domains and 33 mammalian tetraspanins are ubiquitously distributed in various cells and tissues. They interact with other membrane proteins to form tetraspanin-enriched microdomains and serve a variety of functions including cell adhesion, invasion, motility, cell fusion, virus infection, and signal transduction. In this review, we summarize multiple utilities of tetraspanins in the progression of gastric cancer and the underlying molecular mechanisms. In general, the expression of TSPAN8, CD151, TSPAN1, and TSPAN4 is increased in gastric cancer tissues and enhance the proliferation and invasion of gastric cancer cells, while CD81, CD82, TSPAN5, TSPAN9, and TSPAN21 are downregulated and suppress gastric cancer cell growth. In terms of cell motility regulation, CD9, CD63 and CD82 are metastasis suppressors and the expression level is inversely associated with lymph node metastasis. We also review the clinicopathological significance of tetraspanins in gastric cancer including therapeutic targets, the development of drug resistance and prognosis prediction. Finally, we discuss the potential clinical value and current limitations of tetraspanins in gastric cancer treatments, and provide some guidance for future research.

Oligometastatic Gastroesophageal Adenocarcinoma: Molecular Pathophysiology and Current Therapeutic Approach

Gastric and esophageal cancers are dreaded malignancies, with a majority of patients presenting in either a locally advanced or metastatic state. Global incidences are rising and the overall prognosis remains poor. The concept of oligometastasis has been established for other tumor entities and is also proposed for upper gastrointestinal tract cancers. This review article explores metastasis mechanisms on the molecular level, specific to esophageal and gastric adenocarcinoma. Existing data and recent studies that deal with upper gastrointestinal tumors in the oligometastatic state are reviewed. Furthermore, current therapeutic targets in gastroesophageal cancers are presented and discussed. Finally, a perspective about future diagnostic and therapeutic strategies is given.

Liver metastases of gastric cancer: Molecular mechanisms and comprehensive therapy

The liver is the main target organ of metastasis for gastric cancer. Gastric cancer with liver metastases (GCLM) has a poor prognosis and is a challenge for treatment of patients with gastric cancer. At present the mechanism of liver metastases of gastric cancer is unclear, and there have been no unified treatment guidelines. This paper mainly discusses the molecular mechanism and comprehensive therapy of liver metastases of gastric cancer.

Aberrant expression of EphA3 in gastric carcinoma: correlation with tumor angiogenesis and survival

BACKGROUND

EphA3, a member of the Eph receptor tyrosine kinases, plays important roles in tumor angiogenesis and progression. However, the function of EphA3 in solid tumors has not been widely studied. We aimed to explore EphA3 expression in gastric carcinoma and analyze its role as a potential prognostic factor.

METHODS

Quantitative reverse transcription polymerase chain reaction (qRT-PCR) was used to assess EphA3 mRNA in a normal gastric mucosa cell line and carcinoma cell lines. Immunohistochemistry for EphA3 and vascular endothelial growth factor (VEGF) was performed in 318 cases of gastric carcinoma. CD34 immunohistochemical staining was used for microvessel density (MVD) counting. Western blotting was used to analyze EphA3 expression in the cell lines and to determine the expression of EphA3 and VEGF in 75 cases of gastric carcinoma and matched normal mucosa.

RESULTS

EphA3 mRNA and protein expression was significantly higher in gastric cancer than that in normal mucosa (all P < 0.001). EphA3 was significantly correlated with TNM stage and poor prognosis (all P < 0.001). Multivariate analysis showed that EphA3 had an independent effect on survival (P = 0.037). EphA3 was positively correlated with VEGF (P < 0.001), and MVD (P < 0.001). According to Western blot analysis, both EphA3 and VEGF expression were significantly higher in carcinoma than that in normal mucosa (all P < 0.001). A positive correlation was observed between EphA3 and VEGF expression in cancer (P < 0.001, r = 0.513).

CONCLUSIONS

EphA3 may play important roles in the angiogenesis and prognosis of gastric carcinoma, and thus may become a useful target for therapeutic intervention and a potential indicator for clinical assessment of tumor prognosis.

[Expression of CD82/KAI1 and HIF-1α in non-small cell lung cancer and their relationship to vasculogenic mimicry]

背景与目的

新近研究显示血管生成拟态存在于多种高侵袭性肿瘤中, 并与肿瘤细胞的侵袭、转移特性有关, 在形成血管生成拟态的肿瘤中有多种基因表达异常。本研究旨在寻找能预测非小细胞肺癌(non-small cell lung cancer, NSCLC)浸润、转移及术后生存率的指标。

方法

采用免疫组化Elivision^TM plus法和特殊组织化学法检测160例NSCLC和20例正常肺组织中缺氧诱导因子-1α(hypoxia inducible factor-1α, HIF-1α)、CD82/KAI1的表达和血管生成拟态(vasculogenic mimicry, VM)情况。

结果

在正常肺组织中HIF-1α、CD82/KAI1的表达率和VM分别为0、95.0%和0, 在NSCLC组织中分别为48.8%、37.5%和36.9%, 差异有统计学意义(P < 0.01);其水平与肿瘤细胞分化程度、淋巴结转移、临床分期和术后生存期有关(P < 0.01);CD82/KAI1的表达与HIF-1α的表达以及VM呈负相关, HIF-1α的表达水平与VM呈正相关(P < 0.05);CD82/KAI1、HIF-1α的表达以及VM均与微血管密度(microvessel density, MVD)有关联性(P < 0.01)。Kaplan-Meier生存分析表明HIF-1α的过表达和VM均与患者的生存率有关, 阳性的患者生存率明显低于阴性者(P < 0.01);而CD82/KAI1阳性表达的患者生存率明显高于阴性者(P < 0.01);MVD≥22的5年生存率明显低于MVD < 22的生存率(P < 0.01)。多因素分析:pTNM分期、CD82/KAI1、HIF-1α的表达以及VM是影响NSCLC根治术后患者预后的独立因素(P < 0.01)。

结论

CD82/KAI1、HIF-1α在NSCLC组织中的表达水平以及VM与肿瘤的分化程度、转移和预后等均有关, CD82/KAI1、HIF-1α和VM联合检测对NSCLC的进展及预后判断有重要意义。

The pathobiological features of gastrointestinal cancers (Review)

Gastrointestinal adenocarcinoma (GIA) is a common malignant disease worldwide. Its tumorigenesis and progression is a multistage process with the involvement of a multifactorial etiology. Knowledge regarding altered expression of these genes during carcinogenesis may not only provide information about the molecular events during the initiation and progression of cancer, but may also result in the discovery of biological markers for the evaluation of cancer diagnosis and prognosis. In this review, we assessed molecular markers of pathogenesis, invasion, metastasis and prognosis, such as tumor suppressor and metastasis suppressor genes, and angiogenesis, cell adhesion, cell mobility, ER stress, mucin production, threonine protein kinase and REG family protein expression, by the establishment of tissue microarray (TMA) of GIA and immunohistochemistry (IHC) by intermittent microwave irradiation and in situ hybridization (ISH). Finally, we characterized the pathobiological features of Lauren's and WHO subtypes. It was found that the aberrant and cell-specific expression of these molecules is important in the malignant transformation of gastrointestinal epithelium and subsequent progression. These molecules also underlie the histogenic mechanisms of gastric carcinoma according to Lauren's and WHO classification. The combination of TMA, IHC and ISH may be widely applied to screen for molecular markers in GIA.

Modulation of growth and angiogenic potential of oral squamous carcinoma cells in vitro using salvianolic acid B

Background

Our previous studies showed that Salvianolic acid B (Sal B) inhibited 7,12-dimethylbenz[a]anthracene (DMBA)-induced oral carcinogenesis in hamsters and such anti-cancer effects might be related to the inhibition of angiogenesis. This study was aimed to further investigate the anti-proliferative effect of Sal B on the most common type of oral cancer, oral squamous cell carcinoma (OSCC) and the possible mechanisms of action with respect to angiogenesis inhibition.

Methods

Two well-characterized oral squamous cell carcinoma cell lines, CAL27 and SCC4, and premalignant leukoplakia cells were treated with different concentrations of Sal B. Cytotoxicity was assessed by MTT assay. cDNA microarray was utilized to evaluate the expression of 96 genes known to be involved in modulating the biological processes of angiogenesis. Real-time reverse transcription-polymerase chain reaction analysis was conducted to confirm the cDNA microarray data.

Results

Sal B induced growth inhibition in OSCC cell lines but had limited effects on premalignant cells. A total of 17 genes showed a greater than 3-fold change when comparing Sal B treated OSCC cells to the control. Among these genes, HIF-1α, TNFα and MMP9 are specifically inhibited, expression of THBS2 was up-regulated.

Conclusions

Sal B has inhibitory effect on OSCC cell growth. The antitumor effect can be attributed to anti-angiogenic potential induced by a decreased expression of some key regulator genes of angiogenesis. Sal B may be a promising modality for treating oral squamous cell carcinoma.

Role of PTEN in gastric carcinogenesis

The PTEN (phosphatase and tensin homolog deleted on chromosome ten) gene is another important tumor suppressor gene found after p53 gene, and its encoded protein is involved in cellular differentiation, reproduction and apoptosis, as well as cellular adhesion and mobility, and genetic stability that is often lost in various human cancers. Recently, some studies have indicated that down-regulation of PTEN protein expression due to genetic or epigenetic changes, like mutation, loss of heterozygosity (LOH) and promoter hypermethylation, participates in gastric carcinogenesis. These studies could help us understand the pathogenesis of gastric cancer (GC), and show us a new molecular marker that could be used to evaluate TNM stage, histological type, or differentiation grade of GC biopsies, and GC treatment. In this article, we will focus on the functions of PTEN, the mechanisms of its inactivation in GC, and the important role of its inactivation in the development and prognosis of GC.

Role of alternative splicing events in gastric carcinogenesis

Alternative splicing affects many essential biologic processes and is the basis for a number of pathologic conditions, including cancer. Inherited and acquired changes in pre-mRNA splicing have been documented to play a significant role in human disease development. Many cancer-associated genes are regulated by alternative splicing. In this review, we will summarize the evidence supporting the association between alternative splicing and gastric carcinogenesis. The potential significance of alternative splicing events as a target for the diagnosis and treatment of gastric cancer will also be discussed.

Up-regulated EMMPRIN/CD147 protein expression might play a role in colorectal carcinogenesis and its subsequent progression without an alteration of its glycosylation and mRNA level

PURPOSE

Extracellular matrix metalloproteinase inducer (EMMPRIN) was reported to involve in the invasion and metastasis of malignancies by regulating the expression of vascular endothelial growth factor (VEGF) in stromal and cancer cells. The study aimed to clarify the role of EMMPRIN expression in tumorigenesis and progression of colorectal carcinomas (CRC).

METHODS

EMMPRIN expression was examined on tissue microarray containing colorectal carcinomas, adenoma and non-neoplastic mucosa (NNM) by immunohistochemistry and in situ hybridization (ISH). Colorectal carcinoma cell lines (DLD-1, HCT-15, SW480 and WiDr) and tissues were studied for EMMPRIN expression by Western blot or RT-PCR, followed by sequencing.

RESULTS

All carcinoma cell lines showed EMMPRIN expression at both mRNA and protein levels. Two synonymous mutations were found in carcinoma cell lines at codon109 (GCT → GCC: Ala) or 179 (GAT → GAC: Asp). Frozen CRC tissues displayed higher EMMPRIN expression than paired NNM (P < 0.05). EMMPRIN expression was immunohistochemically stronger in colorectal high-grade adenoma, adenocarcinoma and metastatic carcinoma than non-neoplastic superficial epithelium and low-grade adenoma (P < 0.05). In contrast, its mRNA level was similar from colorectal NNM, adenoma to adenocarcinoma by ISH, in line with the findings of RT-PCR (P > 0.05). Immunohistochemically, EMMPRIN expression was positively correlated with tumor size, depth of invasion, vascular or lymphatic invasion, grade of infiltration (INF), ki-67 and VEGF expression of CRCs (P < 0.05). Among them, depth of invasion was an independent associated factor for EMMPRIN expression in CRCs (P < 0.05).

CONCLUSIONS

Up-regulated EMMPRIN protein expression might contribute to colorectal carcinogenesis without the alteration of its glycosylation and mRNA level. Aberrant EMMPRIN protein expression might promote growth or invasion of CRCs possibly through increased ki-67 expression and inducible angiogenesis via up-regulating VEGF expression.

Use of KAI-1 as a prognostic factor in gastric carcinoma

AIMS

The purpose of this study was to investigate the expression level of KAI-1 in gastric carcinomas and compare with the clinicopathological characteristics.

METHODS

KAI-1 expressions were detected with immunohistochemical methods in 257 patients with gastric carcinomas.

RESULTS

KAI-1 was highly expressed in normal gastric epithelium, whereas only 86 of 257 (33.5%) patients with gastric carcinomas were KAI-1 positive. The expression levels, however, decreased with the loss of tumor differentiation, increase in tumor invasion depth, increase in the number of metastatic lymph nodes and perinodal invasions, and progression in the tumor stage. Distant metastatic and stage 4 tumors were all KAI-1 negative. All of these results were statistically significant (P<0.05). There were no correlations between KAI-1 expression and the other parameters such as age, sex, tumor location, tumor size, WHO, Lauren's and Bormann's classifications, neural and angiovascular invasion of the tumor and intestinal metaplasia in adjacent gastric mucosa (P>0.05).

CONCLUSION

Loss of KAI-1 may be considered a significant prognostic parameter in predicting the progression of the gastric carcinomas when evaluated along with the clinical and pathological parameters.

Expression profiling of supraglottic carcinoma: PTEN and thrombospondin 2 are associated with inhibition of lymphatic metastasis

CONCLUSION

Down-regulation of metastasis inhibitor genes PTEN and thrombospondin 2 may play a role in the lymphatic metastasis of supraglottic carcinoma.

OBJECTIVES

To investigate differentially expressed genes in supraglottic squamous cell carcinoma with and without lymphatic metastasis using cDNA microarray.

MATERIALS AND METHODS

cDNA microarray was used to detect the expression profiles of supraglottic carcinoma and the results were validated with real-time PCR.

RESULTS

Compared with normal laryngeal tissues, the expression of 15.6% (15/96) genes including cathepsin B, cathepsin D, cathepsin L, Ets1, c-Ets2, and PEA3 were up-regulated in both cases of supraglottic carcinoma. Compared with the supraglottic carcinoma with no lymph node metastasis, the expression of metastasis inhibitor genes PTEN and thrombospondin 2 was down-regulated in the supraglottic carcinoma tissue with lymph node metastasis.

Down-regulation of the metastasis suppressor protein KAI1/CD82 correlates with occurrence of metastasis, prognosis and presence of HPV DNA in human penile squamous cell carcinoma

In penile squamous cell carcinoma (PSCC), the outcome largely depends on early detection and resection of inguinal lymph node metastases. We investigated the role of metastasis suppressor protein kang ai 1 (KAI1)/cluster of differentiation 82 (CD82), which is known to be of prognostic significance for a wide variety of cancers. Moreover, we analysed the tumours for human papillomavirus (HPV) DNA and loss of heterozygosity at the 11p11.2 locus. Tissue samples of 30 primary PSCCs were investigated immunohistochemically using an anti-KAI1/CD82 polyclonal antibody. The expression was assessed according to the degree of KAI1/CD82-positive tumour cells as positive, decreased or negative. The presence of HPV6/11, HPV16 and HPV18 DNA was analysed by polymerase chain reaction. All patients with decreased or negative expression of KAI1/CD82 in primary lesions had lymph node metastases (p = 0.0002). Patients with positive KAI1/CD82 expression showed a significant better prognosis for survival compared to the other groups (p = 0.0042). Presence of HPV DNA was associated with decreased or negative KAI1/CD82 expression. Lacking or decreased expression of metastasis suppressor gene KAI1/CD82 appears to be a prognostic parameter for the occurrence of lymph node metastases in PSCC. Our study suggests an association of decreased KAI1/CD82 expression with tumour progression, development of metastases and disease-specific death.

Upregulated EMMPRIN/CD147 might contribute to growth and angiogenesis of gastric carcinoma: a good marker for local invasion and prognosis

Tumour growth depends on angiogenesis, which is closely associated with vascular endothelial growth factor (VEGF) and matrix metalloproteinases (MMPs). Extracellular MMP inducer (EMMPRIN) was reported to involve in the progression of malignancies by regulating expression of VEGF and MMPs in stromal cells. To clarify the role of EMMPRIN in progression and angiogenesis of gastric carcinoma, expression of EMMPRIN, ki-67, MMP-2, MMP-9 and VEGF was examined on tissue microarray containing gastric carcinomas (n=234) and non-cancerous mucosa adjacent to carcinoma (n=85) by immunohistochemistry. Additionally, microvessel density (MVD) was assessed after labelling with anti-CD34 antibody. Extracellular MMP inducer expression was compared with clinicopathological parameters of tumours, including levels of ki-67, MMP-2, MMP-9 and vascular endothelial growth factor (VEGF), MVD as well as survival time of carcinoma patients. Gastric carcinoma cell lines (HGC-27, MKN28 and MKN45) were studied for EMMPRIN expression by immunohistochemistry and Western blot. Extracellular MMP inducer expression was gradually increased from normal mucosa to carcinomas through hyperplastic or metaplastic mucosa of the stomach (P<0.05). There was strong EMMPRIN expression in all gastric carcinoma cell lines despite different levels of glycosylation. Extracellular MMP inducer expression was positively correlated with tumour size, depth of invasion, lymphatic invasion, expression of ki-67, MMP-2, MMP-9 and VEGF of tumours (P<0.05), but not with lymph node metastasis, UICC staging or differentiation (P>0.05). Interestingly, there was a significantly positive relationship between EMMPRIN expression and MVD in gastric carcinomas (P<0.05). Survival analysis indicated EMMPRIN expression to be negatively linked to favourable prognosis (P<0.05), but not be independent factor for prognosis (P>0.05). Further analysis showed three independent prognostic factors, depth of invasion, lymphatic and venous invasion, to influence the relationship between EMMPRIN expression and prognosis. Upregulated expression of EMMPRIN possibly contributes to genesis, growth and local invasion of gastric carcinomas. Altered EMMPRIN expression might enhance growth, invasion and angiogenesis of gastric carcinoma via upregulating MMP expression of both stromal fibroblasts and gastric cancer cells and could be considered as an objective and effective marker to predict invasion and prognosis.