OBJECTIVETo study the effects of MTA1 small interfering RNA (siRNA) on the anchorage-independent growth and anoikis of prostate cancer cell line PC-3.

METHODSAfter transfection of human prostate cancer PC-3 cells by MTA1 siRNA, we detected the expression of the MTA1 gene by real-time PCR and Western blot, the anchorage-independent growth of the cells by clone formation in soft agar, and their anoikis by DNA fragmentation assay and flow cytometry.

RESULTSCompared with the control group, MTA1 siRNA transfection significantly decreased the mRNA and protein levels of MTA1, inhibited the anchorage-independent growth of the PC-3 cells, and induced their anoikis, all in a dose- and time-dependent manner (r = 0.935, P = 0.001; r = 0.901, P = 0.0005; r = 0.916, P = 0.0003).

CONCLUSIONMTA1 siRNA can inhibit the anchorage-independent growth of prostate cancer cells by inducing their anoikis.

Anoikis ; genetics ; Gene Expression Regulation, Neoplastic ; Histone Deacetylases ; genetics ; Humans ; Male ; Prostatic Neoplasms ; genetics ; RNA, Small Interfering ; Repressor Proteins ; genetics ; Transfection ; Tumor Cells, Cultured

BACKGROUND AND OBJECTIVEAs a barrier to metastases, cells normally undergo apoptosis after they lose contact with their extra cellular matrix (ECM). This process has been termed "anoikis". Tumour cells that acquire malignant potential have developed mechanisms to resist anoikis and thereby survive after detachment from their primary site while traveling through the lymphatic and circulatory systems. This "anoikis resistance" is considered the first step to tumor metastases. The aim of this study was to screen metastasis-associated genes from anoikis resistant and adherent growth A549 lung cancer cell by Human Genome Array.

METHODSEstablish anoikis resistant A549 lung cancer cell lines by using poly-hydroxyethyl methacrylate resin processed petri dishes, which causes cell free from adherent. The different expressed gene between anoikis resistant A549 cell and adherent growth A549 cell was tested using human V2.0 whole-genome oligonucleotide microarray, a product of Capitalbio Corporation, Beijing. Screen metastasis-associated genes.

RESULTS745 different expressed genes were screened, including 63 highly metastasis-associated genes.

CONCLUSIONThe successfully established anoikis resistant A549 cell lines and screened different expressed genes provide us basis for further research on metastasis of lung cancer.

Anoikis ; genetics ; physiology ; Cell Line, Tumor ; Flow Cytometry ; Gene Expression Profiling ; Genome, Human ; genetics ; Humans ; Lung Neoplasms ; genetics ; Oligonucleotide Array Sequence Analysis

This study examined the effect of CD24 on anoikis of ovarian cancer cells. The expression of CD24 was detected by RT-PCR and Western blotting in ovarian cancer cells with high metastatic potential (HO-8910PM cells) and low metastatic potential (A2780 cells). Cell viability and cell proliferation were detected by MTT assay in suspension culture and adhesion culture. Soft agar culture was used to observe the colony formation. Anoikis was flow cytometrically detected. The results showed that the expression levels of CD24 mRNA and protein were significantly higher in HO-8910PM cells than in A2780 cells (P<0.01). In the suspension culture and soft agar culture, the HO-8910PM cells formed larger and more colonies (35.33 ± 5.51 vs. 16.67 ± 4.04; P<0.01), and showed a stronger resistance to anoikis than A2780 cells did (cell apoptosis rate: 5.93% ± 2 .38% vs. 16.32% ± 2.00%; P<0.01). After treated with CD24 monoclonal antibodies, the number of colony formed in HO-8910PM and A2780 cells was significantly decreased (9.33 ± 2.52 and 8.00 ± 2.00, respectively), and the anoikis rate of the two cell lines was also markedly increased (23.11% ± 2.87% and 28.36% ± 2.29%, respectively). Our study suggested that CD24 may play an important role in the development of anoikis resistance and CD24 can be used as a new therapeutic target to induce anoikis and inhibit metastasis in ovarian cancer.
Anoikis ; CD24 Antigen ; genetics ; metabolism ; Cell Line, Tumor ; Cell Proliferation ; Cell Survival ; Drug Resistance, Neoplasm ; Female ; Humans ; Ovarian Neoplasms ; genetics ; metabolism

OBJECTIVETo investigate the effect and mechanisms of tumor suppressor gene PTEN on the induction of anoikis of hepatocellular carcinoma SMMC-7721 cells.

METHODSSMMC-7721 cells were transfected with GFP plasmids containing wild-type PTEN or phosphatase inactivating mutant PTEN (C124A-PTEN) in vitro; The PTEN expression and the phosphorylation levels of focal adhesion kinase (FAK) and protein kinase B (PKB/Akt) were detected by Western blotting; Flow cytometry assay and laser scanning confocal microscopy were used to analyze apoptosis in adherent and non-adherent cells.

RESULTSCompared with the control, PTEN expression in the cells transfected with wild-type PTEN increased to 248%, while the phosphorylation level of FAK and Akt decreased 65.2% and 89.1%, respectively; and the anoikis percentage increased from 9.5% to 31.3%. In the cells transfected with C124A-PTEN, neither the phosphorylation of FAK and Akt nor the anoikis percentage had obviously changed, although the PTEN expression enhanced dramatically in comparison with the control.

CONCLUSIONThrough its phosphatase activity, tumor suppressor gene PTEN can suppress the phosphorylation of FAK and Akt, and induce anoikis in hepatocellular carcinoma cells.

Anoikis ; physiology ; Carcinoma, Hepatocellular ; pathology ; Focal Adhesion Protein-Tyrosine Kinases ; metabolism ; Humans ; Liver Neoplasms ; pathology ; PTEN Phosphohydrolase ; biosynthesis ; genetics ; Phosphoric Monoester Hydrolases ; metabolism ; Phosphorylation ; Tumor Cells, Cultured

Objective To investigate the effects of microRNA497 (miR-497) on the metastasis of gastric cancer and its possible molecular mechanism. Methods SGC-7901 gastric cancer parent cells were cultured in an ultra-low adhesion environment, and the anoikis resistance model of SGC-7901 cells was created after re-adhesion. Clone formation assay, flow cytometry, Transwell^TM test and scratch healing test were used to detect the differences of biological behavior compared with their parent cells. Fluorescence quantitative PCR was performed to detect the expression of miR-497. Western blot analysis was used to detect the changes of key proteins of Wnt/β-catenin signaling pathway and epithelial mesenchymal transformation (EMT) related proteins such as vimentin and E-cadherin. Parent cells and anoikis resistant SGC-7901 cells were transfected with miR-497 inhibitor or miR-497 mimic, and CCK-8 assay was used to detect the proliferation activity. Transwell^TM invasion assay was performed to detect the invasion ability of cells. Transwell^TM migration test and scratch healing assay was used to determine the migration ability. Western blot analysis was used to detect the expressions of Wnt1, β-catenin, vimentin and E-cadherin. By transfecting miR-497 mimic into the anoikis resistance SGC-7901 cells and inoculating them subcutaneously in nude mice, the changes in the volume and mass of tumor tissues were measured and recorded. Western blot analysis was used to determine the expressions of Wnt1, β-catenin, vimentin and E-cadherin of tumor tissues. Results Compared with the parent cells, the anoikis resistance SGC-7901 gastric cancer cells had faster proliferation rate, stronger colony formation, lower apoptosis rate, stronger invasion and migration ability. The expression of miR-497 was significantly decreased. After down-regulation of miR-497, the proliferation ability, invasion and migration ability were significantly enhanced. The expressions of Wnt1, β-catenin and vimentin increased significantly, while E-cadherin decreased notably. The results of up-regulation miR-497 were the opposite. The tumor growth rate, tumor volume and mass of miR-497 overexpression group were significantly lower than those of control group. The expressions of Wnt1, β-catenin and vimentin decreased significantly, while the expression of E-cadherin increased significantly. Conclusion The expression of miR-497 is low in the anoikis resistance SGC-7901 cells. miR-497 can inhibit the growth and metastasis of gastric cancer cells by blocking Wnt/β-catenin signaling pathway and EMT.
Animals ; Mice ; Humans ; beta Catenin/metabolism* ; MicroRNAs/metabolism* ; Vimentin/metabolism* ; Stomach Neoplasms/pathology* ; Anoikis/genetics* ; Wnt Signaling Pathway/genetics* ; Mice, Nude ; Cell Proliferation/genetics* ; Cadherins/genetics* ; Cell Line, Tumor ; Epithelial-Mesenchymal Transition/genetics* ; Cell Movement/genetics*

Pancreatic cancer is a notorious disease with a poor prognosis and low survival rates, which is due to limited advances in understanding of the molecular mechanism and inadequate development of effective treatment options over the decades. In previous studies, we demonstrated that a novel soluble protein named pancreatic adenocarcinoma up-regulated factor (PAUF) acts on tumor and immune cells and plays an important role in metastasis and progression of pancreatic cancer. Here we show that PAUF promotes adhesiveness of pancreatic cancer cells to various extracellular matrix (ECM). Our results further support a positive correlation of activation and expression of focal adhesion kinase (FAK), a key player in tumor cell metastasis and survival, with PAUF expression. PAUF-mediated adhesiveness was significantly attenuated upon blockade of the FAK pathway. Moreover, PAUF appeared to enhance resistance of pancreatic cancer cells to anoikis via modulation of FAK. Our results suggest that PAUF-mediated FAK activation plays an important role in pancreatic cancer progression.
Anoikis/genetics ; Cell Line, Tumor ; Focal Adhesion Protein-Tyrosine Kinases/*metabolism ; Focal Adhesions/genetics/*metabolism ; Humans ; Lectins/genetics/*metabolism ; Pancreatic Neoplasms/enzymology/genetics/*metabolism ; Proto-Oncogene Proteins pp60(c-src)/metabolism ; Signal Transduction/genetics

Anoikis ; Autophagy ; Autophagy-Related Protein 5 ; genetics ; metabolism ; Blotting, Western ; Cell Line, Tumor ; Humans ; MicroRNAs ; genetics ; metabolism ; Microscopy, Fluorescence ; Microtubule-Associated Proteins ; genetics ; metabolism ; Poly (ADP-Ribose) Polymerase-1 ; metabolism ; Transfection

Metastasis is a multistep process involving modification of morphology to suit migration, reduction of tumor cell adhesion to the extracellular matrix, increase of cell mobility, tumor cell resistance to anoikis, and other steps. MicroRNAs are well-suited to regulate tumor metastasis due to their capacity to repress numerous target genes in a coordinated manner, thereby enabling their intervention at multiple steps of the invasion-metastasis cascade. In this study, we identified a microRNA exemplifying these attributes, miR-124, whose expression was reduced in aggressive MDA-MB-231 and SK-3rd breast cancer cells. Down-regulation of miR-124 expression in highly aggressive breast cancer cells contributed in part to DNA hypermethylation around the promoters of the three genes encoding miR-124. Ectopic expression of miR-124 in MDA-MB-231 cells suppressed metastasis-related traits including formation of spindle-like morphology, migratory capacity, adhesion to fibronectin, and anoikis. These findings indicate that miR-124 suppresses multiple steps of metastasis by diverse mechanisms in breast cancer cells and suggest a potential application of miR-124 in breast cancer treatment.
Anoikis ; Breast Neoplasms ; genetics ; metabolism ; pathology ; Cell Adhesion ; Cell Line, Tumor ; Cell Movement ; Connective Tissue Growth Factor ; metabolism ; DNA Methylation ; Down-Regulation ; Female ; Gene Expression Regulation, Neoplastic ; Humans ; MicroRNAs ; genetics ; metabolism ; Neoplasm Metastasis ; rho GTP-Binding Proteins ; metabolism ; rho-Associated Kinases ; metabolism