Ding Yq

Promotion of colorectal cancer growth and metastasis by the LIM and SH3 domain protein 1

Background LIM and SH3 protein 1 (LASP-1), initially identified from a cDNA library of metastatic axillary lymph nodes of breast cancer patients, is a specific focal adhesion protein involved in numerous biological and pathological processes. The overexpression of LASP-1 has been described in several types of cancers, but the role of LASP-1 in colorectal cancer (CRC) is unknown. In a previous study, comparative proteomic analysis was performed and LASP-1 was identified as a CRC-associated protein in those patients with CRC. Methods Using immunohistochemistry, we analysed LASP-1 protein expression in 126 clinicopathologically characterised CRC cases. Using gene transfection and RNA interference, we investigated the effects of LASP-1 overexpression and depletion on tumor cellular behavior in vitro and in vivo. Using 2-D DIGE, we analysed the effect of the presence and absence of LASP-1 gene on protein expression profiles of CRC cells. Results Overexpression of LASP-1 was found in metastatic CRC tissues (p=0.002), and its expression level was closely correlated with overall survival of patients with CRC (p=0.002). RNA interference-mediated silencing of the LASP-1 gene in SW620 CRC cells inhibited cell proliferation and migration significantly. However, gene transfection-mediated overexpression of LASP-1 in SW480 CRC cells resulted in aggressive phenotypes of cancer cells and promoted cancer growth and metastasis. Furthermore, both overexpression and silencing of the LASP-1 gene caused a very similar protein expression pattern in different CRC cell lines. The identified LASP-1-modulated proteins, including some key cellular molecules, were involved in various biological processes. Conclusions The results show that LASP-1 might be a promising target in the treatment of patients with CRC with growth and metastasis of CRC.

Increased expression of high mobility group box 1 (HMGB1) is associated with progression and poor prognosis in human nasopharyngeal carcinoma

High mobility group box 1 (HMGB1) is a versatile protein with intranuclear and extracellular functions that is involved in numerous biological and pathological processes, such as transcription, DNA repair, and response to infection and inflammation. The expression of HMGB1 has been described in many types of cancers, but the role of HMGB1 in nasopharyngeal carcinoma (NPC) is unknown. The aim of this study was to analyse the roles of HMGB1 in NPC progression and clinical outcome using NPC clinical samples. In an immunohistochemical study, HMGB1 had high expression in 89 of 166 cases of NPC (53.6%). HMGB1 overexpression was significantly associated with T classification (p = 0.01), N classification (p = 0.003), distant metastasis (p = 0.046), and clinical stage (p < 0.001). Patients with higher levels of HMGB1 expression had poorer overall survival and disease‐free survival, whereas patients with lower levels of HMGB1 expression had better survival. Multivariate analysis showed that HMGB1 expression was an independent prognostic indicator for patient survival. Disruption of endogenous HMGB1 using small interfering RNAs suppressed NPC cell invasive ability. These data support the notion that HMGB1 overexpression has a role in the progression of NPC and hence its poor clinical outcome. Copyright

Differential proteomic analysis of human colorectal carcinoma cell lines metastasis-associated proteins

PurposeMetastasis is a common phenomenon and the major lethal cause of colorectal carcinoma (CRC). To better comprehend the mechanism underlying CRC metastasis and to search for potential markers for predicting CRC metastasis, two CRC cell lines with different metastatic potentials, SW480 and SW620, were investigated by phenotypic analyses and proteomics technologies.MethodsThe surgical orthotopic implantation (SOI) technique was originally used to develop a reproducible colorectal cancer model in nude mice with stable tumor growth and metastasizing course. Furthermore, differential proteome analysis of two CRC cell lines was conducted using two-dimensional (2-D) gel electrophoresis combined with matrix-assisted laser desorption/time of flight (MALDI-TOF) mass spectrometry.ResultsAmong the differential spots, 12 protein spots (11 proteins) were further identified using in-gel tryptic digestion and peptide mass fingerprinting (PMF). Interestingly, most of these proteins we identified have been reported to be associated with distinct aspect of tumor metastasis to some extent. Our immunohistochemistry assays of colorectal cancer revealed that heat shock protein (HSP) 27 overexpression relates to metastatic behavior of CRC cell.ConclusionsThe protein profile between two colorectal cell lines with different potential metastasis displayed obvious differences. The results imply that various different proteins may lead to CRC metastasis together. HSP27 overexpression played an important role in metastasis and progression of CRC.

Overexpression of Tiam1 in hepatocellular carcinomas predicts poor prognosis of HCC patients

Little research has been done to test the usefulness of T‐lymphoma invasion and metastasis 1 (Tiam1) as a prognostic marker for hepatocellular carcinoma (HCC). In this study, we investigated Tiam1 expression and its prognostic value for HCC. HCC surgical tissue samples were taken from 152 HCC patients who had been followed up for 5 years. Overexpression of Tiam1 (Tiam1 2+ to 3+) was shown in 63.8% of the cases. The Tiam1 expression level did not correlate with any clinicopathological parameters. However, survival analysis showed that the Tiam1 overexpression group had a significantly shorter overall survival time than the Tiam1 downexpression group (p = 0.008). Multivariate analysis showed that Tiam1 expression was a significant and independent prognostic parameter (p = 0.042) for HCC patients. Tiam1 expression may be a novel and independent predictor for the prognosis of HCC patients.

Proteomic analysis of Tiam1-mediated metastasis in colorectal cancer.

Tiam1 (T lymphoma invasion and metastasis 1), a guanine nucleotide exchange factor that activates Rac, was recently identified as a novel colorectal cancer metastasis‐related gene. To better understand the mechanism underlying Tiam1‐mediated metastasis, we applied two‐dimensional polyacrylamide gel electrophoresis (2‐DE) and matrix‐assisted laser desorption ionization time‐of‐flight mass spectrometry (MALDI‐TOF MS) analysis to identify differentially expressed proteins between Tiam1 transfected and mock transfected colorectal cancer HT29 cells. Eleven differentially expressed proteins were identified and further validated by Western blot and/or real‐time PCR. The results revealed that Tiam1 transfection in colorectal cancer cells could upregulate the expression of Fascin‐1, heat shock protein 27 (HSP27), high‐mobility group box 1 (HMGB1), glutathione S‐transferase omega 1 (GSTO1) and downregulate the expression of annexin IV. These differentially expressed proteins may be directly or indirectly regulated by Tiam1 and be helpful in studying mechanisms that lead to the function of Tiam1. These results give some clues to elucidate the mechanism of Tiam1‐mediated metastasis for colorectal cancer.

Identification of potential genes/proteins regulated by Tiam1 in colorectal cancer by microarray analysis and proteome analysis

Tiam1 (T‐cell lymphoma invasion and metastasis‐inducing protein 1), a guanine nucleotide exchange factor that activates Rac, is a colorectal cancer metastasis‐related gene. In this study, we aimed to better understand the mechanism underlying Tiam1‐mediated metastasis. We applied gene microarray and proteome analysis and compared expression of genes and proteins in a stable Tiam1‐silencing colorectal cancer cell line and in a control cell line. Our analysis identified three genes, high‐mobility group box1 (HMGB1), annexin IV (ANXA4) and phosphoglycerate mutase 1 (PGAM1) that were associated with Tiam1. Analysis of these proteins, which may be directly or indirectly regulated by Tiam1, may provide insight into the role and mechanism of Tiam1 in colorectal cancer metastasis.

MicroRNA-206 functions as a tumor suppressor in colorectal cancer by targeting FMNL2

AbstractBackground Colorectal cancer (CRC) is one of the most common cancers in the world. MicroRNAs play important roles in the progression of CRC. This study aimed to investigate the role of miR-206 and its novel mechanism in the invasion and metastasis of CRC.MethodologyReal-time RT-PCR or Western blotting was used to detect the expressions of miR-206, FMNL2 and c-MET in CRC cell lines and tissues. Luciferase reporter assays were conducted to detect the associations between miR-206 and 3′UTRs of FMNL2 and c-MET. A series of loss-of-function and gain-of-function assays were performed to evaluate the effect of miR-206 on the proliferation, invasion and metastasis of CRC cells.Results miR-206 was significantly down-regulated in CRC tissues and correlated closely with differentiation, lymphatic metastasis and serosal invasion. miR-206 suppressed CRC cell proliferation by arresting CRC cells in the G1/G0 phase and accelerating apoptosis. miR-206 also inhibited cell invasion and lung metastasis in CRC cells. Mechanically, FMNL2 and c-MET were identified as direct targets of miR-206. And FMNL2 rescued the suppression of miR-206 in the proliferation and invasion of CRC cells.ConclusionsThis study revealed functional and mechanistic links between miR-206 and oncogene FMNL2 and c-MET in the progression of CRC. miR-206 functioned as a tumor suppressor in the progression of CRC by targeting FMNL2 and c-MET. Restoration of miR-206 expression may represent a promising therapeutic approach for targeting malignant CRC.

Gene expression profile changes and possible molecular subtypes in differentiated-type nonkeratinizing nasopharyngeal carcinoma

Nasopharyngeal carcinoma (NPC) is a human malignant tumor with a high incidence and a poor prognosis in Southern China and South‐eastern Asia. In this study, we comprehensively analyzed the gene expression profiles in 24 samples of primary differentiated‐type nonkeratining NPC (DNK‐NPC) tissues, 24 samples of normal nasopharyngeal tissues and 4 DNK‐NPC cell lines using cDNA microarray technology and bioinformatics methods. We found expression level of some genes was wildly alerted in the DNK‐NPC samples. In addition, our hierarchical clustering analysis revealed 2 distinctive subtypes of gene expression patterns in DNK‐NPC tissue samples. The discriminator genes were identified using a signal‐to‐noise (S2N) algorithm by permuting of the data set 10,000 times. To further characterize the clinical relevance of the tumor subtypes, we evaluated a surrogate marker, CCND2, differentially expressed between the 2 tumor subgroups by using immunohistochemistry in an independent set of 137 DNK‐NPC samples. CCND2 was highly expressed in the subgroups with “aggressive” features and was associated with T classification (p = 0.006) and clinical stage (p = 0.013). Patients with high level of CCND2 expression had poorer overall survival than those with low level (p = 0.034). Our results suggest that DNK‐NPC can be classified into 2 subtypes based on gene expression patterns, which can be used in determining prognosis and treatment of the tumor.

Down-regulation of DAB2IP promotes colorectal cancer invasion and metastasis by translocating hnRNPK into nucleus to enhance the transcription of MMP2: Down-regulation of DAB2IP

DOC‐2/DAB2 interacting protein (DAB2IP) is a RasGAP protein that shows a suppressive effect on cancer progression. Our previous study showed the involvement of transcription regulation of DAB2IP in metastasis of colorectal cancer (CRC). However, the molecular mechanisms of DAB2IP in regulating the progression of CRC need to be further explored. Here, we identified heterogeneous nuclear ribonucleoprotein K (hnRNPK) and matrix metalloproteinase 2 (MMP2) as vital downstream targets of DAB2IP in CRC cells by two‐dimensional fluorescence difference gel electrophoresis and cDNA microassay, respectively. Mechanistically, down‐regulation of DAB2IP increased the level of hnRNPK through MAPK/ERK signaling pathway. Subsequently, translocation of hnRNPK into nucleus enhanced the transcription activity of MMP2, and therefore promoted invasion and metastasis of CRC. Down‐regulation of DAB2IP correlated negatively with hnRNPK and MMP2 expressions in CRC tissues. In conclusion, our study elucidates a novel mechanism of the DAB2IP/hnRNPK/MMP2 axis in the regulation of CRC invasion and metastasis, which may be a potential therapeutic target.

Malignant glomus tumour of the lung

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