• Asian Pacific Journal of Cancer Prevention
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• 제14권11호
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• pp.6305-6309
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• 2013

Background: TIAM2, a Rac guanine nucleotide exchange factor, is closely associated with cell adherence and migration. Here, we aimed to investigate the role of TIAM2 in non-small cell lung cancer (NSCLC) cells. Materials and Methods: A small interference RNA (siRNA) was introduced to silence the expression of TIAM2. Invasion and motility assays were then performed to assess the invasion and motility potential of NSCLC cells. GST-pull down assays were used to detect activation of Rac1. Results: TIAM2 was highly expressed in NSCLC cells. Knockdown of TIAM2 inhibited the invasion and motility, and suppressed activation of Rac1. Further experiments demonstrated that knockdown of TIAM2 could up-regulate the expression of E-cadherin, and down-regulate the expression of MMP-3, Twist and Snail. Conclusions: Our data suggest that TIAM2 can promote invasion and motility of NSCLC cells. Activation of Rac1 and regulation of some EMT/invasion-related genes may be involved in the underlying processes.

• Asian Pacific Journal of Cancer Prevention
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• 제13권2호
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• pp.613-615
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• 2012

The aim of this study was to ana1yze T-cell lymphoma invasion and metastasis-inducing factor 1 (Tiam1) expression in 1ung cancer patients. A total of 204 patients with lung cancer tissue lesions were enrolled in the present study, along with 40 cases of normal lung tissue and 40 of normal fetal lung tissue. Tiam1 protein expression level was determined using intensity quantitative analysis, for comparison in lung cancer, metastatic, normal lung, and fetal lung tissue. The positive unit (PU) of Tiam1 was $13.5{\pm}5.42$ in lung cancer,$5.67{\pm}1.56$ in norma1 epithelial cells, and $5.89{\pm}1.45$ in fetal lung epithelial cells. The value in the lung cancer tissue was significantly higher than that in the normal lung tissue and the fetal lung tissue (P<0.01). The Tiam1 PU values with lymph node metastasis and without 1ymph node metastasis were $15.2{\pm}4.34$ and $12.5{\pm}4.23$, respectively, and the difference was statistically significant (P<0.05). The Tiam1 PU values in different tumor, nodes, metastasis (TNM) stages, III-IV period, and I-II phase were $14.7{\pm}4.14$ and $11.0{\pm}5.34$ (P<0.05). A correlation was found between Tiam1 expression and the age of patient, tumor size, tumor type, and tumor differentiation. Tiam1 protein expression in the lung tumor tissue is significantly higher than that in the normal lung tissue and fetal lung tissue. Tiam1 expression may be closely related to lung cancer development and metastasis.

• Asian Pacific Journal of Cancer Prevention
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• 제14권1호
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• pp.201-208
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• 2013

Objective: To investigate changes in the invasive capacity of gastric cancer cells in vitro after expression inhibition of T lymphoma invasion and metastasis inducing factor 1 (Tiam 1) and underlying mechanisms. Methods: Using adhesion selection, two subpopulations with high ($M_H$) or low ($M_L$) invasive capacity were separated from the human gastric cancer cell line MKN-45 ($M_0$). Tiam 1 antisense oligodeoxynucleotide (ASODN) was transfected into $M_H$ cells with liposomes, and expression of Tiam 1 mRNA and protein was determined by RT-PCR and quantitative cellular-ELISA. Changes in the cytoskeleton, invasive capacity in vitro and expression of ras-related $C_3$ botulinum toxin substrate 1 (Rac 1), integrin ${\beta}1$ and matrix metalloproteinase 2 (MMP 2) between Tiam 1 ASODN transfected $M_H$ cells and non-transfected cells were observed by HE staining, cytoskeletal protein staining, scanning electron microscopy, Boyden chamber tests and cyto-immunohistochemistry. Results: A positive correlation existed between the expression level of Tiam l mRNA or protein and the invasion capacity of gastric cancer cells. After ASODN treatment ($0.43{\mu}M$ for 48 h), Tiam 1 mRNA transcription and protein expression in $M_H$ cells were decreased by 80% and 24% respectively (P < 0.05), compared with untreated controls, while invasive capacity in vitro was suppressed by 60% (P < 0.05). Morphologic and ultrastructural observation also showed that ASODN-treated $M_H$ cells exhibited smooth surfaces with obviously reduced filopodia and microspikes, which resembled $M_0$ and $M_L$ cells. Additionally, cytoskeletal distribution dramatically altered from disorder to regularity with reduced long filament-like structure, projections, pseudopodia on cell surface, and with decreased acitn-bodies in cytoplasm. After Tiam 1 ASODN treatment, the expression of Rac 1 and Integrin ${\beta}1$ in $M_H$ cells was not affected (P > 0.05), but that of MMP 2 in $M_H$ cells was significantly inhibited compared with untreated cells (P < 0.05). Conclusion: Over-expression of Tiam-1 contributes to the invasive phenotype of gastric cancer cells. Inhibition of Tiam 1 expression could impair the invasive capacity of gastric cancer cells through modulating reconstruction of the cytoskeleton and regulating expression of MMP 2.

• Asian Pacific Journal of Cancer Prevention
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• 제14권6호
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• pp.3681-3684
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• 2013

Deregulated miRNAs participate in osteosarcoma genesis. In this study, the expression of miRNA-218 in human osteosarcomas, adjacent normal tissues and Saos-2 human osteosarcoma cells was first assessed. Then the precise role of miRNA-218 in osteosarcoma cells was investigated. Upon transfection with a miR-218 expression vector, the proliferation of Saos-2 human osteosarcoma cells determined using the ATPlite assay was significantly suppressed, whilw migration of Saos-2 cells detected by wound healing and invasion determined using transwells were dramatically inhibited. Potential target genes of miR-218 were predicted and T-cell lymphoma invasion and metastasis 1 (TIAM1) and matrix metalloproteinase 2 (MMP2) and 9 (MMP9) were identified. This was confirmed by western blotting, which showed that miR-218 expression inhibited TIAM1, MMP2 and MMP9 protein expression. Collectively, these data suggest that miR-218 acts as a tumor suppressor in osteosarcomas by down-regulating TIAM1, MMP2 and MMP9 expression.

• Journal of Chest Surgery
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• 제42권2호
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• pp.141-147
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• 2009

배경: 폐암의 암화과정에 관여하는 21번 염색체 장완에 존재하는 종양억제유전자를 발굴하고자 하였다. 대상 및 방법: 21q11.2 구역의 USP25, 21q21.2 구역의 NCAM2, ADAMTS1, 그리고 21q22.1 구역의 Claudin-8 (CLDN8), Claudin-17 (CLDN17), TIAM1 유전자를 대상으로 비소세포폐암 세포주에서 이들 유전자의 발현 정도와 돌연변이 및 촉진자 메틸화 유무를 조사하였다. 결과: 13가지 비소세포폐암 세포주 가운데 7가지 세포주(L132, H157, H358, H522, H1299, H1703, HCC2108)에서 CLDN8, CLDN17의 발현이 유의하게 감소되었고, ADAMTS1의 경우 6가지 세포주(A549, SW900, H1299, H1373, H1703, H1793)에서 발현양이 유의하게 감소되었다. 유전자 발현의 감소가 있는 세포주와 그렇지 않은 세포주간의 PCR-SSCP의 band pattern의 차이가 없으며 염기서열의 분석에서도 genetic alteration은 관찰되지 않았다. 발현이 감소되어 있는 세포주에 5-Aza-CdR을 처리한 경우 유전자의 발현양이 유의하게 증가되었다. 결론: ADMTS1, CLDN8, CLDN17 유전자는 폐암의 암화과정에 관여하는 종양억제유전자일 가능성을 시사하며, 유전자의 발현 감소는 유전자 촉진자 부위의 methylation에 의함을 시사한다.