Macrophage migration inhibitory factor promotes breast cancer metastasis via activation of HMGB1/TLR4/NF kappa B axis.

Macrophage migration inhibitory factor (MIF) is up-regulated in diverse solid tumors and acts as the critical link between immune response and tumorigenesis. In this study, we demonstrated that MIF overexpression promoted migration of breast cancer cells by elevating TLR4 expression. Further investigation evidenced that MIF induced ROS generation. MIF-induced ROS led to ERK phosphorylation, which facilitated HMGB1 release from the nucleus to the cytoplasm. MIF overexpression also induced caveolin-1 phosphorylation. Caveolin-1 phosphorylation contributed to HMGB1 secretion from the cytoplasm to the extracellular matrix. The extracellular HMGB1 activated TLR4 signaling including NF-κB phosphorylation, which was responsible for the transcription of Snail and Twist as well as MMP2 activation. Furthermore, MIF-induced caveolin-1-dependent HMGB1 secretion might control the recruitment of CD11b+ immune cells. Our data suggested that MIF affected the intrinsic properties of tumors and the host immune response in tumor microenvironment by regulating the TLR4/HMGB1 axis, leading to metastasis of breast cancer.

Decreased HCRP1 expression is associated with poor prognosis in breast cancer patients.

BACKGROUND: Downregulation of hepatocellular carcinoma related protein 1 (HCRP1) has been reported to be associated with a poor prognosis in a variety of malignant tumors. The purpose of this study was to assess HCRP1 expression in breast cancer and to examine its possible correlation with commonly used prognostic factors, particularly epidermal growth factor receptor (EGFR). METHODS: Immunohistochemical analysis was performed on tumors from 194 patients with primary breast cancer. HCRP1 expression was analyzed along with major clinicopathological variables. RESULTS: HCRP1 protein expression was shown to be correlated with age (P = 0.001), histological grade (P = 0.005), tumor progression (P = 0.013), and death (P = 0.001), but not with tumor size, lymph-node metastasis, or Ki67 status. Kaplan-Meier survival curves showed that lower HCRP1 expression was significantly correlated with increased short-term survival (P < 0.001), and both univariate and multivariate analyses revealed that HCRP1, tumor size, lymph-node metastasis, and human epidermal growth factor receptor-2 (HER-2) were independent prognostic factors (all P < 0.05). In addition, low HCRP1 expression was much more frequent in triple negative breast cancer (TNBC; 63.89%) than in luminal (16.95%) and HER-2 overexpression phenotypes (7.5%; P < 0.001), and significant correlations between HCRP1 and survival time were observed for the TNBC group (P < 0.004). Furthermore, an inverse relationship between HCRP1 and EGFR expression was found both for the complete set of all cases (P < 0.001), and for each phenotype analyzed individually (P < 0.05). CONCLUSION: Our results suggest that HCRP1 may play an important role in EGFR regulation and that its decreased expression is an independent predictor of breast cancer, especially in TNBC patients.

Role of mitochondrial function in the protective effects of ischaemic postconditioning on ischaemia/reperfusion cerebral damage.

OBJECTIVE: To investigate the effects of ischaemic postconditioning on brain injury and mitochondria in focal ischaemia and reperfusion, in rats. METHODS: Adult male Wistar rats (n = 15 per group) underwent sham surgery, ischaemia (2-h middle cerebral artery occlusion), or ischaemia followed by ischaemic postconditioning (three cycles of 30 s reperfusion/30 s reocclusion). Brain infarction size, neurological function, mitochondrial reactive oxygen species (ROS) production, mitochondrial membrane potential and mitochondrial swelling were evaluated 24 h postsurgery. RESULTS: Infarct size was significantly smaller, and neurological function was significantly better, in the ischaemic postconditioning group than in the ischaemia group. Ischaemia resulted in significant increases in mitochondrial ROS production and swelling, and a reduction in mitochondrial membrane potential, all of which were significantly reversed by postconditioning. CONCLUSIONS: The protective role of ischaemic postconditioning in focal ischaemia/reperfusion may be due to decreased mitochondrial ROS production, reduced mitochondrial membrane potential and suppressed mitochondria swelling. Mitochondria are potential targets for new therapies to prevent brain damage caused by ischaemia and reperfusion.