S2013030013217), the Guangdong Natural Science Fund (grant no. to the cytoplasm and into the extracellular space. In addition, the overexpression of TCTP led to the activation of NF-B in LoVo cells, and this effect was reversed by treatment with antibodies targeting HMGB1 or to its receptors Toll-like receptor 4 (TLR4) and receptor for advanced glycation end products advanced glycation end products (RAGE). Furthermore, inhibition of the HMGB1-TLR4/RAGE-NF-B pathway significantly inhibited the TCTP-stimulated invasion of LoVo cells. experiments demonstrated that the over-expression of TCTP in nude mice promoted the development and spread of xenografted tumors, and concurrently enhanced the expression of HMGB1 in tumor tissues. Collectively, these findings suggested that TCTP promotes CRC metastasis through regulating the behaviors of HMGB1 and the downstream activation of the NF-B signaling pathway. luciferase was used as an internal control. The cell extracts were prepared in luciferase cell culture lysis buffer (Promega). The activities of firefly and luciferases were measured sequentially from a single sample with the Dual Luciferase Reporter Assay system (Promega) using a Lumat LB 9507 luminometer (Bethold Technologies, Bad Wildbad, Germany). Tumor xenografts Male BALB/c nude mice (n=6 each group), aged from 6 to 8 8 weeks and weighing approximately 18C22 g, were supplied by the Laboratory Animal Center of Southern Medical University (Guangzhou, China). All mice were bred under specific pathogen-free conditions, at light periods of 12 h each day, and were fed water and mouse chow experiments, it was noted that TCTP induced the cytoplasmic translocation of HMGB1 and its further release into the extracellular environment. These findings support the hypothesis that HMGB1 can be secreted from CRC cells, which has been documented previously (14,27), and provide important novel insight that the secretion of HMGB1 is regulated by TCTP. Furthermore, in xenograft tumors in nude mice, it was found that augmentation of expression of TCTP promoted liver metastasis of CRC cells, which was accompanied by a marked increase in the expression of HMGB1. This finding confirmed that TCTP regulated the behavior of HMGB1, which may produce synergistic effects on the formation and metastasis of CRC. It appears that, Angiotensin 1/2 (1-5) when secreted from cells, HMGB1 becomes a multifunctional cytokine for regulating cell proliferation, survival and migration (12C17). Previous evidence indicates that extracellular HMGB1 is not only involved in chronic inflammatory-reparative responses, which contribute to tumor cell survival and metastasis (27C29), but also induces apoptosis in immune cells, resulting in an attenuation of anticancer immune responses (30). TLR and RAGE, the main receptors Angiotensin 1/2 (1-5) of HMGB1, also contribute to the progression and metastasis of CRC (31C35). It has been shown that the HMGB1-TLR-RAGE tripod frequently activates the downstream NF-B signaling pathway (17C19), and it has subsequently been demonstrated that dimerized TCTP, the biologically active form of TCTP, can also activate the NF-B pathway and induce inflammation (36). However, there is no literature concerning whether the NF-B pathway is involved in TCTP-promoted tumor cell invasion and metastasis. The present study provided evidence that TCTP stimulated the activation of NF-B in colon adenocarcinoma cells, and that this was abrogated by antibodies against HMGB1, TLR4 or RAGE. These results indicated that TCTP can induce the activation of NF-B through the Angiotensin 1/2 (1-5) mediation of HMGB1 and its receptors TLR4 and RAGE. In addition, it was found that TCTP and the successive activation of the HMGB1-TLR4/RAGE-NF-B pathway enhanced the invasion potential Mouse monoclonal to IL-16 of LoVo cells, whereas the specific NF-B inhibitor Bay117082 attenuated the increased invasiveness of tumor cells. This indicated that the activation of NF-B signaling is essential for TCTP-mediated tumor cell migration and invasion. Although experimental studies have revealed the importance of Angiotensin 1/2 (1-5) NF-B in the initiation and propagation of CRC, the mechanisms underlying how NF-B promotes tumor metastasis remain to be fully elucidated. There.