The tumor microenvironment is composed of tumor cells, fibroblasts, endothelial cells and infiltrating immune cells, which may inhibit or promote tumor growth and progression. The objectives of this retrospective study were to characterize the density of tumor-associated macrophages (TAMs) in breast cancer, and to correlate the density of TAMs with clinicopathological parameters. Paraffin-embedded specimens and clinicopathological data, including up to 5 years follow-up information, were obtained from 172 breast cancer patients. Immunohistochemical staining for CD68 (marker for macrophages) was performed and evaluated in a blinded fashion. We found that TAMs were significantly frequent in high histopathological grade breast cancer patients. Breast cancer patients with a high density of TAMs had significantly lower rates of disease-free survival and 5-year overall survival than patients with low density of TAMs. Furthermore, high-infiltration of TAMs indicated worse survival rate for patients with node-negative breast cancer. In conclusion, the number of TAMs in the tumor stroma is an independent predictor of survival time for breast cancer patients. High-infiltration of TAMs is a significant unfavorable prognostic factor for patients with invasive breast cancer and, as such, is a potentially useful prognostic marker for breast cancer.
BackgroundEstrogen plays a critical role in breast cancer (BC) progression through estrogen receptor (ER)-mediated gene regulation. Emerging studies suggest that the malignant progress of BC cells is influenced by the cross talk between microRNAs (miRNAs) and ER-α signaling. However, the mechanism and functional linkage between estrogen and miRNAs remain unclear.MethodsThe expression levels of miR-196a and SPRED1 in BC were tested by qRT-PCR in 46 paired BC and adjacent tissues and by the GEO datasets. The role of miR-196a in estrogen-induced BC development was examined by CCK-8 assay, wound healing assay, Matrigel invasion assay and tumorigenicity assay in nude mice. The binding site of ER-α in miR-196a promoter region was analyzed by ChIP-seq, ChIP assay and luciferase reporter assay. The potential targets of miR-196a in BC cells were explored using the luciferase reporter assay and western blot analysis, and the correlation between miR-196a and SPRED1 was analyzed by Spearman’s correlation analysis in BC specimens and GEO dataset. TCGA BRCA data was used to characterize the ESR1 signatures according to MSigDB gene set.ResultsThe expression levels of miR-196a were higher in ER-positive (ER+) breast tumors compared to ER-negative (ER-) tumor tissue samples. Besides, miR-196a was involved in estrogen-induced BC cell proliferation, migration and invasion. Notably, the up-regulation of miR-196a was mediated by a direct interaction with estrogen receptor α (ER-α) but not estrogen receptor β (ER-β) in its promoter region, and miR-196a expression levels were positively correlated to ER-α signature scores. Furthermore, SPRED1 was a new direct target of miR-196a which participated in miR-196a-promoted BC development and was suppressed by ligand-activated ER-α signal pathway. Finally, forced expression of miR-196a induced tumor growth of MCF7 cells, while inhibition of miR-196a significantly suppressed the tumor progress in vivo.ConclusionsOverall, the identification of estrogen/miR-196a/SPRED1 cascade will shed light on new molecular mechanism of estrogen signaling in BC development and therapy.Electronic supplementary materialThe online version of this article (10.1186/s12943-018-0830-0) contains supplementary material, which is available to authorized users.
Colorectal cancer (CRC) is one of the leading cancer-related causes of death in the world. Recently, downregulation of microRNA-497 (miR-497) has been observed in CRC tissues. In this study, we found that miR-497 expression levels were downregulated in human CRC specimens compared to the adjacent normal tissues. MiR-497 expression levels were strongly correlated with clinical stages and lymph node metastases. Furthermore, kinase suppressor of ras 1 (KSR1), a known oncogene, was a direct target of miR-497, and KSR1 expression levels were inversely correlated with miR-497 expression levels in human CRC specimens. Overexpression of miR-497 inhibited cell proliferation, migration, invasion and increased chemosensitivity to 5-fl uorouracil treatment, whereas forced expression of KSR1 had the opposite effect. Taken together, these results revealed that lower miR-497 levels in human CRC tissues induce KSR1 expression which is associated with CRC cancer occurrence, advanced stages, metastasis and chemoresistance. Lower miR-497 levels may be a potential biomarker for CRC advanced stages and treatment response.
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