Autophagy is a highly conservative biological behavior in eukaryotic cells. This dynamic process involves "wrapping" cytoplasmic components and combining with lysosomes in cells for catabolism. The catabolic effect of autophagy can eliminate toxic substances in cells, maintain homeostasis in the intracellular environment, and produce small molecules, such as amino acids, which nourish cells, thereby allowing them to survive. Autophagy can inhibit the occurrence of tumors by maintaining homeostasis in the intracellular environment. However, it can promote the proliferation, invasion, and metastasis of malignant tumor cells. Autophagy can regulate the microenvironment of tumor cells and has an important role in a series of processes, such as anoikis, tumor dormancy, and epithelial-mesenchymal transition.
Anoikis ; Autophagy ; Humans ; Neoplasm Invasiveness ; Neoplasms

OBJECTIVETo study the regulation of anoikis by tyrosine kinase receptor B (TrkB) in human nasopharyngeal carcinoma lines. METHODS; Expression levels of TrkB and brain-derived neurotrophic factor (BDNF) were evaluated by RT-PCR and Western blot. Colony formation ability of C666-1 was observed in soft agar. Proliferation rate and apoptosis, that change in cells by treating the TrkB inhibitor K252a and specificity ligand BDNF respectively under suspension culture, were measured by cell counting kit-8 (CCK-8) assay and the flow cytometry assay. The expression change of TrkB, BDNF and phosphorylation of serine threonine kinase (p-Akt) were investigated by Western blot analysis.

RESULTSTrkB and BDNF were identified in C666-1 cells. C666-1 cells could be decreased the proliferation of colony in soft agar by effect of K252a, but BDNF could make the colony prolific. K252a can inhibit the expression of TrkB in C666-1, and prevent p-Akt activation. And exogenous BDNF stimulated up-regulation TrkB and p-Akt, induced anoikis resistance.

CONCLUSIONTrkB inhibits anoikis in nasopharyngeal carcinoma cells. Inhibiton of TrkB by K252a can induce anoikis, and may prove particularly effective in treatment of nasopharyngeal carcinoma.

Anoikis ; Carcinoma ; Cell Line, Tumor ; Humans ; Nasopharyngeal Neoplasms ; metabolism ; pathology ; Receptor, trkB ; metabolism

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

Lung cancer remains the primary cause of cancer-related death in the world, and the number of cases continues to increase. Like any other human cancer, the development of lung cancer is associated with the activation of oncogenes or inactivation of tumor suppressor genes. Phosphatase and tensin homolog, deleted on chromosome ten (PTEN), is a part of a complex signaling system that affects a variety of important cell functions. PTEN opposes the action of phosphatidylinositol 3-kinase (PI3-kinase) by dephosphorylating the signaling lipid phosphatidylinositol 3, 4, 5-triphosphate (PIP3). In addition, it displays weak tyrosine phosphatase activity, which may down modulate the signaling pathways involving focal adhesion kinase (FAK) or Shc. Functions for PTEN have been identified in the regulation of many normal cell processes, including growth, adhesion, migration, invasion and apoptosis. PTEN appears to play particularly important roles in regulating anoikis (apoptosis of cells after loss of contact with extracellular matrix) and cell migration. Many studies have suggested that the loss of PTEN expression occurs commonly in primary lung cancers and correlates with the histological type. Regulation of PTEN expression may provide a new preventive and therapeutic modality in primary lung cancer. However, there is, in our opinion, a need for further study of this gene
Anoikis ; Apoptosis ; Cell Movement ; Focal Adhesion Protein-Tyrosine Kinases ; Genes, Tumor Suppressor ; Humans ; Lung Neoplasms* ; Lung* ; Oncogenes ; Phosphatidylinositol 3-Kinase ; Phosphatidylinositols ; Signal Transduction ; Tyrosine

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

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

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

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

Hepatocyte growth factor (HGF) is one of major growth factors in the bone marrow microenvironments with which the proliferation, differentiation and migration of bone marrow-derived mesenchymal stem cells were closely contacted. However, its roles in the regulation of proliferation, differentiation and migration of bone marrow-derived mesenchymal stem cells remain unclear. This study was aimed to investigate the effect of HGF on biological characteristics of bone marrow-derived mesenchymal stem cells. Expression of c-Met, the receptor for HGF was detected by immunohistochemistry assay, cell proliferation was determined by MTT, activity of ALP was quantitatively assayed, cell migration and anoikis-induced MSC apoptosis were analyzed. The results showed that HGF not influenced the proliferation and osteogenic differentiation of bone marrow-derived mesenchymal stem cells. Treatment of bone marrow-derived mesenchymal stem cells with recombinant human hepatocyte growth factor resulted in inhibition of anoikis-induced apoptosis. HGF significantly stimulated the migration of bone marrow-derived mesenchymal stem cells. Both PI-3 kinase and MAPK kinase were proved to be involved in HGF-induced migration. It is concluded that HGF/c-Met signal regulates the apoptosis and migration of bone marrow-derived mesenchymal stem cells.
Anoikis ; drug effects ; Bone Marrow Cells ; cytology ; drug effects ; metabolism ; Cell Movement ; drug effects ; Cell Proliferation ; drug effects ; Cells, Cultured ; Hepatocyte Growth Factor ; pharmacology ; Humans ; Immunohistochemistry ; Mesenchymal Stromal Cells ; cytology ; drug effects ; metabolism ; Proto-Oncogene Proteins c-met ; biosynthesis