Anti-Integrin β1 (Y783) Antibody (A25469)

Low back pain is associated with intervertebral disc degeneration (IVDD) due to cellular loss through apoptosis. Mechanical factors play an important role in maintaining the survival of the annulus fibrosus (AF) cells and the deposition of extracellular matrix. However, the mechanisms that excessive mechanical forces lead to AF cell apoptosis are not clear. The present study was to look for how AF cells sense mechanical changes. In vivo experiments, the involvement of mechanoreceptors in apoptosis was examined by RT-PCR and/or immunoblotting in the lumbar spine of rats subjected to unbalanced dynamic and static forces. In vitro experiments, we investigated apoptotic signaling pathways in untransfected and transfected AF cells with the lentivirus vector for rat β1 integrin overexpression after cyclic stretch. Apoptosis in AF cells was assessed using flow cytometry, Hoechst 33258 nuclear staining. Western blotting was used to analyze expression of β1 integrin and caspase-3 and ERK1/2 MAPK signaling molecules. In the rat IVDD model, unbalanced dynamic and static forces induced apoptosis of disc cells, which corresponded to decreased expression of β1 integrin. Cyclic stretch-induced apoptosis in rat AF cells correlated with the activation of caspase-3 and with decreased levels of β1 integrin and the phosphorylation levels of ERK1/2 activation level. However, the overexpression of β1 integrin in AF cells ameliorated cyclic stretch-induced apoptosis and decreased caspase-3 activation. Furthermore, ERK1/2-specific inhibitor promotes apoptosis in vector β1-infected AF cells. These results suggest that the disruption of β1 integrin signaling may underlie disc cell apoptosis induced by mechanical stress. Further work is necessary to fully elucidate the pathophysiological mechanisms that underlie IVDD caused by unbalanced dynamic and static forces.

In this study, a microgel composed of chitosan and inorganic phosphates was used to deliver poly(lactic-co-glycolic acid) (PLAGA) microspheres loaded with sphingolipid growth factor FTY720 to critical size cranial defects in Sprague Dawley rats. We show that sustained release of FTY720 from injected microspheres used alone or in combination with recombinant human bone morphogenic protein-2 (rhBMP2) improves defect vascularization and bone formation in the presence and absence of rhBMP2 as evaluated by quantitative microCT and histological measurements. Moreover, sustained delivery of FTY720 from PLAGA and local targeting of sphingosine 1-phosphate (S1P) receptors reduces CD45+ inflammatory cell infiltration, promotes endogenous recruitment of CD29+CD90+ bone progenitor cells and enhances the efficacy of rhBMP2 from chitosan microgels. Companion in vitro studies suggest that selective activation of sphingosine receptor subtype-3 (S1P3) via FTY720 treatment induces smad-1 phosphorylation in bone-marrow stromal cells. Additionally, FTY720 enhances stromal cell-derived factor-1 (SDF-1) mediated chemotaxis of CD90+CD11B-CD45- bone progenitor cells in vitro after stimulation with rhBMP2. We believe that use of such small molecule delivery formulations to recruit endogenous bone progenitors may be an attractive alternative to exogenous cell-based therapy.

In the past several years, the αv integrin subfamily has been repeatedly found to be involved in tumor progression and angiogenesis. The aim of this study was to investigate the expression of the integrin αv subfamily in laryngeal squamous cell carcinoma (LSCC), and to correlate the expression rate with tumor biological behavior and angiogenesis of the LSCC. The integrin αv subfamily, including αv, β1, β3, β5, β6 and β8 subunits, was immunohistochemically found to be expressed in 64 patients with LSCC, and we analyzed the relationship between the expression rate and the clinicopathological stage of this cancer. Immunohistochemical staining for CD105 was carried out in the same group of the patients. The intratumoral microvessel density (IMVD) of the LSCC was calculated by CD105 staining, and the correlation between the IMVD and αv subfamily expression was discussed. The results showed that all members of the integrin αv subfamily could be detected in the LSCC. The expression rate of integrin αv and β5 subunits in primary cancer was significantly higher than in normal tissue, and their expression rate in the group with lymphatic metastasis was significantly higher than in the group without metastasis. The IMVD of the group with positive expression of αv and β5 subunits was significantly higher than in the group with negative expression, but there were no significant effects on the β1, β3, β6 and β8 subunits in these biological processes. In conclusion, the expressions of integrin αv and β5 subunits were significantly associated with lymphatic metastasis and angiogenesis of the LSCC. Among the members of integrin αv subfamily, integrin αvβ5 might play an important role in invasion and metastases of the LSCC, and it may become a valuable marker for the evolution of the LSCC.

Hypoxia-induced epithelial mesenchymal transition (EMT) is an essential step in cancer metastasis. Luteolin, a flavonoid that is widely distributed in plants, is a novel anticancer agent. However, the mechanism underlying its anticancer effects remains undefined. In this study, for the first time, we demonstrate that luteolin inhibits hypoxia-induced EMT in human non-small cell lung cancer cells in culture, which is demonstrated by the fact that hypoxia-induced EMT reduced the expression of E-cadherin and other epithelial markers and increased the expression of N-cadherin, vimentin and other mesenchymal markers; these effects were markedly attenuated by luteolin. In addition, luteolin also inhibited hypoxia-induced proliferation, motility and adhesion in the cells. Furthermore, we reveal that luteolin inhibits the expression of integrin β1 and focal adhesion kinase (FAK).Since integrin β1 and FAK signaling are closely related to EMT formation, these results suggest that luteolin inhibits hypoxia-induced EMT, at least in part, by inhibiting the expression of integrin β1 and FAK.

Because cells are sensitive to mechanical forces,microgravity might act on stress-dependent cell changes. Regulation of focal adhesions (FAs) and cytoskeletal activity plays a role in cell maintenance, cell movement,and migration. Human MCF-7 cells were exposed to modeled microgravity (MMG) to test the hypothesis that migration responsiveness to microgravity is associated with cytoskeleton and FA anomalies. MMG acts on MCF-7 cells by disorganizing cytoskeleton filaments (microfilaments and microtubules). Microfilaments in MMG did not display their typical radial array. Likewise, microtubules were disrupted in MCF-7 cells within 4 h of initiation of MMG and were partly reestablished by 48 h. FAs generated inmicrogravity were less mature than those established in controls, shown by reduced FAs number and clustering. In parallel, MMG decreased kinases activity (such as FAK,PYK2, and ILK) of FAs in MCF-7 cells. The expression of both integrinbeta1 and integrinbeta4 were downregulated by MMG. We conclude that cytoskeletal alterations and FAs changes in MMG are concomitant with cell invasion and migration retardation. We suggest that reduced migration response in MCF-7 cells following MMG is linked to changes of cytoskeleton and FAs.

PURPOSE:

We evaluated the higher levels of carcinoembryonic antigen (CEA) secreted by the LoVo human colon carcinoma cells in a medium containing anticancer drugs. Drug-resistant LoVo cells were analyzed by subcutaneously xenotransplanting them into mice. The aim of this study was to evaluate whether the drug-resistant cells isolated in this study were cancer-initiating cells, known also as cancer stem cells (CSCs).

METHODS:

The production of CEA was investigated in LoVo cells that were cultured with 0-10 mM of anticancer drugs, and we evaluated the increase in CEA production by the LoVo cells that were stimulated by anticancer drug treatment. The expression of several CSC markers in LoVo cells treated with anticancer drugs was also evaluated. Following anticancer drug treatment, LoVo cells were injected subcutaneously into the flanks of severe combined immunodeficiency mice in order to evaluate the CSC fraction.

RESULTS:

Production of CEA by LoVo cells was stimulated by the addition of anticancer drugs. Drug-resistant LoVo cells expressed lower levels of CSC markers, and LoVo cells treated with any of the anticancer drugs tested did not generate tumors within 8 weeks from when the cells were injected subcutaneously into severe combined immunodeficiency mice. These results suggest that the drug-resistant LoVo cells have a smaller population of CSCs than the untreated LoVo cells.

CONCLUSION:

Production of CEA by LoVo cells can be stimulated by the addition of anticancer drugs. The drug-resistant subpopulation of LoVo colon cancer cells could stimulate the production of CEA, but these cells did not act as CSCs in in vivo tumor generation experiments.