B7-H3, a novel member of the B7 family, was previously known as a regulatory ligand regulating T-cell-mediated immune response, and in recent years it was found to take a significant role in various cancers. In some tumor types, high expression of B7-H3 had been linked to a poor prognosis, whereas in other cancers the opposite effect had been observed. The precise role of B7-H3 in tumor immunity is unclear, and further investigations are needed. In the present study, we studied the expression of B7-H3 in the pathologic specimens of 221 patients treated for breast cancer by immunohistochemistry. Strong B7-H3 expression was found in cancer tissues from 80.55% patients, and B7-H3 expression had a negative relation with vascular endothelial growth factor (VEGF) expression, microvascular density for CD34, and tumor size. Furthermore, through lipopolysaccharide-mediated delivery of stable short hairpin ribonucleic acid we observed that silencing of B7-H3 could increase the transcription and secreting of VEGF in breast cancer cell line MCF-7. In summary, the present study demonstrated that B7-H3 suppressed tumor growth through inhibiting VEGF expression. These results increased knowledge of the nonimmunological role of B7-H3 protein and provided novel insights into great biological functions and a putative therapeutic target in breast cancer.

B7-H3, a member of the B7 family of molecules, is expressed in certain types of human cancer and is important in tumor development and progression. Although several studies have reported that the expression of B7-H3 is correlated with poor outcomes in patients with cancer, its exact role in cancer remains unknown. In the present study, the expression levels of B7-H3 in the pathological specimens of 105 patients treated for non-small cell lung cancer (NSCLC) were examined by immunohistochemistry. A high expression level of B7-H3 was observed in 46.9% of the 105 NSCLC tissue specimens. These patients demonstrated a more advanced tumor grade and a shorter survival time. In addition, we also examined the levels of tumor-associated macrophages (TAMs) in NSCLC tissues and observed that the levels were positively correlated with the expression of B7-H3, and that higher levels of macrophages were associated with lower levels of infiltrating T cells and a shorter survival time. These results demonstrated that TAMs are important in the evasion of tumor immune surveillance in NSCLC. Furthermore, through knockdown of B7-H3 by RNA interference, we observed that soluble B7-H3 was capable of inducing macrophages to express higher levels of macrophage mannose receptor (MMR) and lower levels of human leukocyte antigen (HLA)-DR, as well as higher levels of interleukin-10 (IL-10) and lower levels of IL-1β in vitro. These observations are characteristic of an anti-inflammatory/reparatory (alternative/M2) phenotype. Therefore, our data suggests that B7-H3 proteins are involved in the progression of NSCLC by inducing the development of monocytes into anti-inflammatory cells.

MTT assay showed that NOChR markedly inhibited proliferation of SGC-7901 cells in a dose-dependent manner, and when IC(50) was 4.14 micromol/L, the potency of NOChR was 10 times than that of lead compound, chrysin (ChR, IC(50) was 40.56 micromol/L), and was similar to 5-fluorouracil (5-FU, IC(50) was 4.51 micromol/L). FCM with propidium iodide (PI) staining demonstrated that the apoptosis rates of SGC-7901 cells treated with 1.25, 5.00 and 20.00 micromol/L NOChR for 48 h were 9.8% +/- 0.2%, 36.8% +/- 1.9% and 45.5% +/- 3.5%, respectively, and were significantly higher when treated with 5.00 and 20.00 micromol/L NOChR than that with 20.00 micromol/L ChR (12.9% +/- 1.5%). DNA agarose gel electrophoresis showed that treatment of SGC-7901 cells with 20.00 micromol/L NOChR for 48 h resulted in typical DNA ladder bands of DNA of SGC-7901 cells, which could be eliminated by treating with 10.00 micromol/L GW9662, a blocker of PPARgamma. Western blot analysis revealed that after 24 h of treatment with 20.00 micromol/L NOChR, PPARgamma and Bax protein expression of SGC-7901 cells increased but Bcl-2 expression decreased; however, pre-incubation with 10.00 micromol/L GW9662 could efficiently antagonize and weaken the regulatory effect of 20.00 micromol/L NOChR on Bax and Bcl-2 protein expression of SGC-7901 cells.