Overexpression of carboxypeptidase A4 (CPA4) is associated with poor prognosis in patients with gastric cancer.
ABSTRACT: CarboxypeptidaseA4 (CPA4) is a zinc-containing exopeptidases, and its aberrant expression has been implicated in cancer development and progression. However, few studies have investigated the association between CPA4 over-expression and clinical significance in gastric cancer (GC). In this study, we employed immunohistochemistry to evaluate the expression of CPA4 in gastric cancer tissues, and found that elevated CPA4 expression was detected in 64% (n=100) of primary GCs, but was weak or no staining in the normal mucosa. Clinical relevance analysis showed that positive staining for CPA4 was significantly associated with Tumor size, Stage, Lymph node metastasis, Depth of invasion and Distant metastasis. As tumor markers p53 and Ki67 are closely associated with tumor progression, we further analyzed the correlations between CPA4 levels and these two factors. We found that abnormal expression of CPA4 was positively associated with Ki67 (P=0.002) and reversely correlated with p53 (P=0.035) in GC. In Kaplan-Meier survival analysis, high levels of CPA4 were significantly associated with unfavorable survival in GC patients (P<0.001). Multivariate Cox regression model showed that high expression of CPA4 was an independent prognostic factor for GC patients. In conclusion, our results suggested that CPA4 was highly expressed in gastric cancer tissues. Overexpression of CPA4 can be used as an independent poor prognostic factor in gastric cancer.
Project description:Hypoxia induces the expression of several genes through the activation of a master transcription factor, hypoxia-inducible factor (HIF)-1?. This study shows that hypoxia strongly induced the expression of two carboxypeptidases (CP), CPA4 and CPE, in an HIF-1?-dependent manner. The hypoxic induction of <i>CPA4</i> and <i>CPE</i> gene was accompanied by the recruitment of HIF-1? and upregulation in the active histone modification, H3K4me3, at their promoter regions. The hypoxic responsiveness of <i>CPA4</i> and <i>CPE</i> genes was observed in human adipocytes, human adipose-derived stem cells, and human primary fibroblasts but not mouse primary adipocyte progenitor cells. CPA4 and CPE have been identified as secreted exopeptidases that degrade and process other secreted proteins and matrix proteins. This finding suggests that hypoxia changes the microenvironment of the obese hypoxic adipose tissue by inducing the expression of not only adipokines but also peptidases such as CPA4 and CPE.
Project description:Due to contradictious findings of previous studies regarding Ki67's value in gastric cancer (GC), we reevaluated the expression of Ki67 in whole tissue sections (WTS) and tissue microarrays (TMAs) of GC testing the following hypotheses: does Ki67 show intratumoral heterogeneity; are TMAs representative in the determination of the Ki67 proliferation index (PI); is the Ki67 PI subject to an intralaboratory variability; and is the Ki67 PI related to clinico-pathological patient characteristics and/or prognostically relevant in GC.Corresponding WTS and TMAs samples from 315 GCs were stained immunohistochemically. The Ki67 PI evaluated on WTS was correlated with the Ki67 PI evaluated on TMAs, sample age, clinico-pathological characteristics, and patient survival.The overall amount of Ki67-positive tumor cells did not depend on sample age. Three distinct, partly heterogeneous Ki67 expression patterns were observed. The mean Ki67 PI evaluated on TMAs differed on average minus 16.9% from the Ki67 PI evaluated on WTS. Ki67 in WTS correlated significantly with the Laurén phenotype and tumor grade, but not with patient survival.TMAs carry the risk of a systematic underestimation of the Ki67 PI. Ki67 has no prognostic value in GC but might be a potential indicator of intratumoral heterogeneity.
Project description:Using whole transcriptome analysis and a lentiviral short hairpin RNA screening library, carboxypeptidase A4 (CPA4) was identified as a novel marker in breast cancer and a therapeutic target in triple?negative breast cancer (TNBC) in the present study. Immunohistochemistry was used to evaluate the presence of CPA4, estrogen receptor, progesterone receptor, human epidermal growth factor receptor 2, Ki67, epidermal growth factor receptor, cytokeratin 5/6, aldehyde dehydrogenase 1, cluster of differentiation (CD)44, CD24, claudins, E?cadherin, vimentin and androgen receptor in 221 cases of breast cancer, including 68 TNBC cases. The effects of CPA4 on the viability and migration ability of TNBC cells were analyzed using RNA interference methods. Increased CPA4 expression, specifically in the cytoplasm of cancer tissue cells, was detected. Furthermore, high CPA4 expression in TNBC cases was associated with low expression of E?cadherin and with the expression of cancer stem cell markers (high CD44/low CD24). Patients with TNBC and high levels of CPA4 expression had a significantly poorer prognosis compared with those with low CPA4 expression. Notably, viability and migration were reduced, but E?cadherin expression was upregulated in CPA4?suppressed TNBC cells. The present data suggested that CPA4 may be a novel inducer for epithelial?mesenchymal transition, which is characterized by the downregulation of E?cadherin and mesenchymal phenotypes. To conclude, CPA4 may be a marker for poor prognosis and a promising therapeutic target in TNBC with aggressive phenotypes.
Project description:An increasing body of evidence indicates that miR-149 can both suppress and promote tumor growth depending on the tumor type. However, the role of miR-149 in the progression of gastric cancer (GC) remains unknown. Here we report that miR-149 is a tumor suppressor in human gastric cancer. miR-149 expression is decreased in GC cell lines and clinical specimens in comparison to normal gastric epithelial cell and tissues, respectively. The expression levels of miR-149 also correlate with the differentiation degree of GC cells and tissues. Moreover, ectopic expression of miR-149 in gastric cancer cells inhibits proliferation and cell cycle progression by down-regulating ZBTB2, a potent repressor of the ARF-HDM2-p53-p21 pathway, with a potential binding site for miR-149 in its mRNA's 3'UTR. It is also found that ZBTB2 expression increases in GC cells and tissues compared to normal gastric epithelial cell and tissues, respectively. Silencing of ZBTB2 leads to suppression of cell growth and cell cycle arrest in G0/G1 phase, indicating that ZBTB2 may act as an oncogene in GC. Furthermore, transfection of miR-149 mimics into gastric cancer cells induces down-regulation of ZBTB2 and HDM2, and up-regulation of ARF, p53, and p21 compared to the controls. In summary, our data suggest that miR-149 functions as a tumor suppressor in human gastric cancer by, at least partially through, targeting ZBTB2.
Project description:Background:Liver kinase B1 (LKB1) is a newly discovered tumor suppressor gene that plays a role in apoptosis induction. However, the precise impact of LKB1 expression on gastric cancer (GC) progression and its correlation with survivin and p53 in GC have not yet been elucidated. Purpose:The aim of this study was to explore the significance of LKB1 expression and its correlation with p53 and survivin in GC. Patients and methods:In this study, LKB1 expression was detected in GC and adjacent paracancerous tissues from 150 patients through immunohistochemical (IHC) staining. The relationship between LKB1 expression and clinical pathological factors in GC was analyzed, alongside its correlation with p53 and survivin expression. Results:LKB1 expression was reduced in GC tissues compared with adjacent paracancerous tissues (P=0.001). In patients with GC, lower LKB1 expression was associated with greater invasion depth (P=0.013), higher pTNM stage (P=0.009), and lymph node metastasis (P=0.029). Furthermore, LKB1 expression in GC was inversely associated with p53 (r=-0.181, P=0.027) and survivin expression (r=-0.198, P=0.015). Kaplan-Meier analysis indicated that the expression of LKB1, p53 and survivin, as well as tumor differentiation, invasion, and pTNM and lymph node metastasis were all associated with overall survival (OS) (all P<0.05). Finally, multivariate analysis showed that LKB1 expression [hazard ratio (HR): 0.605 (0.414-0.882), P=0.009], p53 expression [hazard ratio (HR): 1.840 (1.232-2.750), P=0.003], and survivin expression [hazard ratio (HR): 1.561 (1.039-2.345), P=0.032] were all independent prognostic factors for patients with GC. Conclusion:Our study suggests that LKB1 expression is reduced in GC, negatively correlated with p53 and survivin expression, and plays an important role in predicting invasion and metastasis of GC.
Project description:Promoter methylation plays a vital role in tumorigenesis through transcriptional silencing of tumor suppressive genes. Using genome-wide methylation array, we first identified PBX/Knotted Homeobox 2 (PKNOX2) as a candidate tumor suppressor in gastric cancer. PKNOX2 mRNA expression is largely silenced in gastric cancer cell lines and primary gastric cancer via promoter methylation. Promoter methylation of PKNOX2 was associated with poor survival in gastric cancer patients. A series of in vitro and in vivo functional studies revealed that PKNOX2 functions as a tumor suppressor. Ectopic PKNOX2 expression inhibited cell proliferation in GC cell lines and suppressed growth of tumor xenografts in mice via induction of apoptosis and cell cycle arrest; and suppressed cell migration and invasion by blocking epithelial-to-mesenchymal transition. On the other hand, knockdown PKNOX2 in normal gastric epithelial cells triggered diverse malignant phenotypes. Mechanistically, PKNOX2 exerts its tumor suppressive effect by promoting the up-regulation of Insulin like Growth Factor Binding Protein 5 (IGFBP5) and TP53. PKNOX2 binds to the promoter regions of IGFBP5 and TP53 and transcriptionally activated their expression by chromatin immunoprecipitation (ChIP)-PCR assay. IGFBP5 knockdown partly abrogated tumor suppressive effect of PKNOX2, indicating that the function(s) of PKNOX2 are dependent on IGFBP5. IGFBP5 promoted PKNOX2-mediated up-regulation of p53. As a consequence, p53 transcription target genes were coordinately up-regulated in PKNOX2-expressing GC cells, leading to tumor suppression. In summary, our results identified PKNOX2 as a tumor suppressor in gastric cancer by activation of IGFBP5 and p53 signaling pathways. PKNOX2 promoter hypermethylation might be a biomarker for the poor survival of gastric cancer patients.
Project description:CPA4 belongs to a member of the metallocarboxypeptidase family, and its expression in pancreatic cancer samples and clinical significance are still not investigated until now. In this study, we aimed to evaluate the level of CPA4 in pancreatic cancer samples and study its clinical implications as a diagnostic marker for pancreatic cancer. The levels of CPA4 in pancreatic cancer tissues and serum samples were measured by immunohistochemistry (IHC) and enzyme-linked immunosorbent assay (ELISA), respectively. Among 150 pancreatic cancer tissues examined, 86.7% (130/150) of cases showed positive staining for CPA4. Clinicopathological relevance analysis showed that CPA4 expression was correlated with advanced clinical stage and lymph node metastasis. Also, we found that the levels of CPA4 in serum samples were significantly high in cases whose expression was also high in paired tissue samples (N=50). In a larger sample set, we found that serum CPA4 in pancreatic cancer patients was significantly higher than for healthy controls (P<0.05). In addition, high serum CPA4 was significantly associated with the TNM stage, Lymph node involvement and distant metastasis. At a cutoff value of 0.3 ng/ml, CPA4 might be a better diagnostic biomarker of pancreatic cancer than CA199. In conclusion, CPA4 overexpression is associated with pancreatic cancer progression, and it might be a potential diagnostic serum marker for pancreatic cancer.
Project description:Patient-derived xenografts (PDX) have a biologically stable in tumor architecture, drug responsiveness, mutational status and global gene-expression patterns. Numerous PDX models have been established to date, however their thorough characterization regarding the tumor formation and rates of tumor growth in the established models remains a challenging task. Our study aimed to provide more detailed information for establishing the PDX models successfully and effectively.We transplanted four different types of solid tumors from 108 Chinese patients, including 21 glioblastoma (GBM), 11 lung cancers (LC), 54 gastric cancers (GC) and 21 colorectal cancers (CRC), and took tumor tissues passaged for three successive generations. Here we report the rate of tumor formation, tumor-forming times, tumor growth curves and mortality of mice in PDX model. We also report H&E staining and immunohistochemistry for HLA-A, CD45, Ki67, GFAP, and CEA protein expression between patient cancer tissues and PDX models.Tumor formation rate increased significantly in subsequent tumor generations. Also, the survival rates of GC and CRC were remarkably higher than GBM and LC. As for the time required for the formation of tumors, which reflects the tumor growth rate, indicated that tumor growth rate always increased as the generation number increased. The tumor growth curves also illustrate this law. Similarly, the survival rate of PDX mice gradually improved with the increased generation number in GC and CRC. And generally, there was more proliferation (Ki67+) in the PDX models than in the patient tumors, which was in accordance with the results of tumor growth rate. The histological findings confirm similar histological architecture and degrees of differentiation between patient cancer tissues and PDX models with statistical analysis by GraphPad Prism 5.0.We established four different types of PDX models successfully, and our results add to the current understanding of the establishment of PDX models and may contribute to the extension of application of different types of PDX models.
Project description:Gastric cancer (GC) is one of the most common human cancers. The molecular mechanisms underlying GC carcinogenesis and progression are still not well understood. In this study, we showed that heterogeneous nuclear ribonucleoprotein K (HNRNPK) was an effective prognostic marker for GC patients especially in early stage. Overexpression of HNRNPK can retard tumor cell proliferation and colony formation in vitro and inhibit tumor growth in vivo through p53/p21/CCND1 axis. Bioinformatics analyses indicated that HNRNPK associated genes were enriched in cell cycle and DNA replication process. Protein-protein interaction network showed that HNRNPK was physically interacted with p53, p21 and other cancer related genes. Besides, GSEA showed that HNRNPK expression was positively correlated with GAMMA radiation response and DNA repair, while negatively correlated with angiogenesis, TGF-? and Hedgehog pathway activation. Finally, several chemicals including Glycine that may repress GC progression through upregulating HNRNPK are suggested. Our study demonstrated that HNRNPK may play as a tumor suppressor in gastric cancer and could be a potential therapeutic target for GC.
Project description:This study aims to investigate the prognostic power of carcinoembryonic antigen-related cell adhesion molecule 6 (CEACAM6) in gastric cancer (GC) and its potential role in cancer development and progression. Data mining results show that CEACAM6 is overexpressed in gastric cancer and is correlated with lymph node metastasis. Subsequently, immunohistochemical staining was performed to determine CEACAM6 protein levels in paraffin gastric tumor specimens. Real-time reverse-transcription-polymerase chain reaction (RT-PCR) was conducted to detect CEACAM6 mRNA levels in fresh GC samples. CEACAM6 protein and mRNA levels were significantly up regulated in GC compared with paired normal mucosa. The IHC staining intensity of CEACAM6 was positively correlated with tumor size, Lauren's classification, vascular invasion, lymph node metastasis, distant metastasis, and TNM stage. CEACAM6 expression was inversely correlated with the five-year survival rate of GC patients. Cox multivariate analysis results demonstrated that the overall survival was independently correlated with CEACAM6 expression. A significant association was observed between CEACAM6 and distant metastases. Network analysis of downstream gene signatures revealed several hub genes such as SRC and DNM1L etc. which may mediating tumor promoting functions of CEACAM6. Further data mining discovered that Tamoxifen etc. could be therapeutic alternatives for gastric patients with CEACAM6 overexpression. Collectively, CEACAM6 overexpression is a common characteristic of GC and is associated with poor 5 year survival rate in GC. Besides, potential molecular mechanisms and treatment options were also provided.