TIMP-1 interaction with αvβ3 integrin confers resistance to human osteosarcoma cell line MG-63 against TNF-α-induced apoptosis

Abstract

Tumor necrosis factor-α (TNF-α) is a pleiotropic cytokine affecting diverse cellular responses. TNF-α is cytotoxic in many systems, but it can also act as an anti-apoptotic signal to promote cell survival pathways activated through integrins and extracellular matrix components. This is particularly evident in cancer cells. To unravel the basis of resistance to TNF-α-induced apoptosis, human osteosarcoma MG-63 cell line was used. Our data showed that resistance to apoptosis was accompanied by high levels of TIMP-1 expression in part mediated by NF-κB activation, whereas under apoptotic conditions, in the presence of cycloheximide (CHX), TIMP-1 and αvβ3 integrin protein levels were significantly reduced. Silencing TIMP-1 using siRNA led to increased apoptosis following treatment with TNF-α, whereas exogenously-added recombinant TIMP-1 reduced the extent of apoptosis. Immunoprecipitation and confocal microscopy experiments demonstrated that TIMP-1 interacted with αvβ3 integrins. The biological role of this interaction was revealed by the use of echistatin, an antagonist of αvβ3 integrin. In the presence of echistatin, decreased protection against apoptosis by recombinant TIMP-1 was observed.

NOV inhibits proliferation while promoting apoptosis and migration in osteosarcoma cell lines through p38/MAPK and JNK/MAPK pathways

“…P38/MAPK and JNK/MAPK signaling pathways, which have been confirmed to be tightly associated with tumor cell apoptosis (18,19), including osteosarcoma (20,21), are two important intracellular signaling pathways. Certain studies have suggested that NOV was able to induce cell apoptosis or growth inhibition in various types of cancer through the activation of MAPKs signaling, such as choriocarcinoma, nephroblastoma and Ewing sarcoma (13).…”

The Role of Integrins in Osteosarcoma

“…Previous studies have correlated TIMP-1 expression to the inhibition of apoptosis [25,26] , and elevated TIMP-1 levels among cancer patients corresponded to poorer survival rates and increased chemotherapy resistance [27] . In the specific context of OS, treatment of MG-63 cells with TNF-α resulted in a 5-fold increase of TMP-1 secretion and upregulation of αvβ3 integrin, which was concomitant with apoptotic resistance [22] . Moreover, addition of the integrin inhibitor echistatin disrupted TIMP-1 ligation to αvβ3 and significantly decreased apoptotic resistance [22] .…”

“…In the specific context of OS, treatment of MG-63 cells with TNF-α resulted in a 5-fold increase of TMP-1 secretion and upregulation of αvβ3 integrin, which was concomitant with apoptotic resistance [22] . Moreover, addition of the integrin inhibitor echistatin disrupted TIMP-1 ligation to αvβ3 and significantly decreased apoptotic resistance [22] . In summary, increased αvβ3 integrin expression in tumor cells is directly correlated to the metastatic potential of multiple human OS cell lines including 143B, SAOS, U2OS, and MG-63 [20][21][22][23] .…”

“…Furthermore, the inhibition of formyl peptide receptor-1 (FPRL-1), an SAA receptor which regulates chemotaxis, corresponded to down regulation of SAA-induced αvβ3 integrin expression [23] . In another study, Tsagaraki et al [22] demonstrated that the interaction between αvβ3 integrin and tissue inhibitor of metalloproteinase-1 (TIMP-1) confers resistance in the MG-63 OS cell line against apoptosis induced by tumor necrosis factor-α (TNF-α). Previous studies have correlated TIMP-1 expression to the inhibition of apoptosis [25,26] , and elevated TIMP-1 levels among cancer patients corresponded to poorer survival rates and increased chemotherapy resistance [27] .…”

“…Other studies have also evaluated the cross-talk between αvβ3 integrin and various pathways that play a role in chemotaxis and apoptosis [22,23] . For example, Ren et al [24] found that serum amyloid A (SAA), which has been shown to regulate integrin expression and cytoskeleton arrangement, enhances the migratory and invasive ability of U2OS cells in a concentration and timedependent manner [23] .…”