B7-H1 and B7-H3, two members of the B7 family that are thought to regulate T-cell activation, are expressed in human non-small cell lung cancer (NSCLC). However, their prognostic significance is poorly understood. In the present study we reported that B7-H1 and B7-H3 were expressed in 96/128 (72.7%) and 89/128 (69.5%) samples, respectively. B7-H1 and B7-H3 expression and the number of infiltrating T-cell intracellular antigen-1+ and interferon-γ+ cells in NSCLC tissues were significantly higher than those in the adjacent tissues (p<0.01). High B7-H1 or B7-H3 expression was associated with lymph node metastasis and TNM stage (p<0.05, respectively). Sex, TNM stage, B7-H1, B7-H3, and T-cell intracellular antigen-1 expression remained significant prognostic factors after adjusting for other prognostic factors in a multivariate Cox proportional hazards regression model. In vitro studies revealed that knockdown of B7-H3 on tumor cells enhanced T-cell growth and interferon-γ secretion when stimulated by anti-CD3 and anti-CD28 monoclonal antibodies. Interferon-γ reduced CXCR4 expression on cancer cells and inhibited the CXCL12-induced cell migration. B7-H1 and B7-H3 are independent predictors of poorer survival in patients with NSCLC. Interference of the signal pathways of these negative regulatory molecules might be a new strategy for treating NSCLC.

We found that artesunate (ART) inhibited the growth of MCF-7 and MDA-MB-231 breast cancer cells. ART arrested the cell cycle in the G2/M phase, which was accompanied by an upregulation of p21. ART upregulated the expression of Beclin1, an initiator of autophagy (type II programmed cell death). In addition, ART stimulated the aggregation of LC3, which is considered to be a marker of autophagosome formation. We further verified the transformation of LC3 from type I into type II. 3-MA, a classical autophagy inhibitor, attenuated ART-induced autophagosome formation, cell growth repression, G2/M arrest, and p21 upregulation. Autophagy induction and p21 upregulation were also repressed by knockdown of Beclin1. Furthermore, ART sensitized breast cancer cells to the chemotherapeutic agent epirubicin through an autophagy-dependent cascade. Our study showed that ART induced autophagy in breast cancer cells and indicated that the anticancer effects of ART were exerted through an autophagy pathway. Moreover, ART sensitized breast cancer cells to epirubicin chemotherapy. Our results provide a basis for further development of ART as a novel therapeutic agent for the treatment of breast cancer.

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Cancer metastasis is a highly coordinated and dynamic multistep process in which cancer cells interact with a variety of host cells. Morphological studies have documented the association of circulating tumor cells with host platelets. Tumor cell-induced platelet aggregation (TCIPA) contributes significantly to hematogenous metastasis; however, the molecular mechanisms involved in breast cancer TCIPA are poorly characterized. In this study, MCF-7 metastatic human breast cancer cells induced dose-dependent aggregation of washed platelets. Four major platelet activation pathways, glycoprotein (GP)-Ib-IX, GPIIb/IIIa, thromboxane (TX)-A2 and adenosine diphosphate (ADP) were activated during TCIPA and were inhibited by their respective inhibitors, 7E3, SZ-1, aspirin and apyrase. Pretreatment of platelets with 7E3, SZ-1 or apyrase significantly inhibited TCIPA, while pretreatment with aspirin had no effect. Moreover, combined pretreatment of platelets with 7E3, SZ-1 and apyrase significantly inhibited TCIPA, compared to single inhibitors. Combinations of antiplatelet drugs may represent a promising strategy to prevent cancer metastasis.

PurposeDespite new developments in cancer therapy, chemotherapy and radiotherapy remain the cornerstone of breast cancer treatment. Therefore, finding ways to reduce the toxicity and increase sensitivity is particularly important. Tumor necrosis factor alpha (TNF-α) exerts multiple functions in cell proliferation, differentiation and apoptosis. In the present study, we investigated whether TNF-α could enhance the effect of chemotherapy and radiotherapy against breast cancer cells.MethodsCell growth was determined by MTT assay in vitro, and by using nude mouse tumor xenograft model in vivo. Cell cycle and apoptosis/necrosis were evaluated by flow cytometry. DNA damage was visualized by phospho-Histone H2A.X staining. mRNA expression was assessed by using real-time PCR. Protein expression was tested by Western blot assay.ResultsTNF-α strengthened the cytotoxicity of docetaxel, 5-FU and cisplatin against breast cancer cells both in vitro and in vivo. TNF-α activated NF-κB pathway and dependently up-regulated expressions of CyclinD1, CyclinD2, CyclinE, CDK2, CDK4 and CDK6, the key regulators participating in G1→S phase transition. As a result, TNF-α drove cells out of quiescent G0/G1 phase, entering vulnerable proliferating phases. Treatment of TNF-α brought more DNA damage after Cs137-irradiation and strengthened G2/M and S phase cell cycle arrest induced by docetaxel and cisplatin respectively. Moreover, the up-regulation of RIP3 (a necroptosis marker) by 5-FU, and the activation of RIP3 by TNF-α, synergistically triggered necroptosis (programmed necrosis). Knockdown of RIP3 attenuated the synergetic effect of TNF-α and 5-FU.ConclusionTNF-α presented radiotherapy- and chemotherapy-sensitizing effects against breast cancer cells.