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Macrophages are a double-edged sword with potential cancer-promoting and anticancer effects. Controversy remains regarding the effect of macrophages, especially M1 macrophages, on tumor promotion and suppression. We aimed to investigate the role of M1 macrophages in the occurrence and progression of esophageal squamous cell carcinoma (ESCC). Analyzing the data in Gene Expression Omnibus database by the CIBERSORT algorithm found that M1 macrophages were one of the important components of many immune cells in ESCCs, and the increase in their number was obviously negatively correlated with tumor T staging. This result was verified by our experimental data: the density of CD68/HLA-DR double-stained M1 macrophages in ESCC tumor nest and tumor stroma was significantly higher than that in cancer-adjacent normal (CAN) tissues. The density of M1 macrophages in ESCC tumor nest was negatively correlated with the patient's lymph node metastasis and clinical stage (P < 0.05), and the negative tendency was more obvious for M1 macrophages in ESCC tumor stroma (P < 0.001). Exposure to M1 macrophage-conditioned medium inhibited ESCC cell migration and invasion ability significantly (P < 0.05). Moreover, the increased M1 macrophage density in ESCC tumor stroma correlated positively with good prognosis of ESCC. M1 macrophages were involved in inhibiting ESCC cell migration and invasion, which could serve as a good prognostic factor in patients with ESCC. [ABSTRACT FROM AUTHOR]

Dysregulation of microRNA (miRNA) biogenesis is implicated in cancer development and progression. Dicer and Drosha are established regulators of miRNA biogenesis. In this study, we used a miRNA array to evaluate the miRNA expression profiles in nasopharyngeal carcinoma (NPC) samples. The significance analysis of microarrays showed a global downregulation of miRNA expression in NPC samples compared with normal nasopharyngeal epithelial tissues. Notably, miR-18a, a member of the oncogenic miR-17–92 cluster, was upregulated in the NPC samples and ell lines. Clinical parameter studies showed that higher levels of miR-18a correlated with NPC advanced stage, lymph node metastasis, Epstein-Barr virus infection and a higher death rate from NPC, indicating oncogenic roles in NPC development. The expression levels of miR-18a and Dicer1 were inversely related in NPC tissues. Further studies demonstrated that miR-18a negatively regulated Dicer1 by binding to the 3′ untranslated regions of Dicer1. In vitro and in vivo biological function assays showed that miR-18a promoted the growth, migration and invasion of NPC cells by regulating Dicer1 expression, which caused the global downregulation of miRNA expression levels including miR-200 family and miR-143. Furthermore, we found that the epithelial mesenchymal transition marker E-cadherin and the oncogene K-Ras were aberrantly expressed after miR-18a transduction, and these alterations were directly induced by downregulation of the miR-200 family and miR-143. Collectively, our findings indicate that miR-18a plays an oncogenic role in the development of NPC by widespread downregulation of the miRNome and could be a potential therapeutic target for NPC. [ABSTRACT FROM PUBLISHER]

Emerging evidence has pointed to biological roles of melanoma-associated antigens (MAGEs) in cancer development, progression and resistance to treatment. However, the mechanisms involved remain to be fully elucidated. In this report, we show that one of the MAGE proteins, MAGE-D2, suppresses the expression of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) death receptor 2 (TRAIL-R2) and plays an important role in protecting melanoma cells from apoptosis induced by TRAIL. MAGE-D2 was commonly expressed at increased levels in melanoma cells compared with melanocytes. Although its inhibition by small interfering RNA (siRNA) did not cause cell death, it rendered melanoma cells more sensitive to TRAIL-induced apoptosis. This was associated with enhanced formation of TRAIL death-inducing signaling complex and up-regulation of TRAIL-R2, and was blocked by a recombinant TRAIL-R2/Fc chimeric protein or siRNA knockdown of TRAIL-R2. Regulation of TRAIL-R2 by MAGE-D2 appeared to be mediated by p53, in that knockdown MAGE-D2 did not up-regulate TRAIL-R2 in p53-null or mutant p53 melanoma cells. In addition, inhibition of MAGE-D2 did not result in up-regulation of TRAIL-R2 in wild-type p53 cell lines with p53 inhibited by short hairpin RNA. Indeed, knockdown of MAGE-D2 led to up-regulation of p53 due to a transcriptional increase. The regulatory effect of MAGE-D2 on TRAIL-R2 expression and TRAIL-induced apoptosis was recapitulated in studies on fresh melanoma isolates. Taken together, these results identify the expression of MAGE-D2 as an important mechanism that inhibit TRAIL-induced apoptosis and suggest that targeting MAGE-D2 may be a useful strategy in improving the therapeutic efficacy of TRAIL in melanoma. [ABSTRACT FROM PUBLISHER]