Project description:Background: Docosahexaenoic acid (DHA) is a natural compound with anticancer and anti-angiogenesis activity that is currently under investigation as both a preventative agent and an adjuvant to breast cancer therapy. However, the precise mechanisms of DHA’s anticancer activities are unclear. It is understood that the intercommunication between cancer cells and their microenvironment is essential to tumor angiogenesis. Exosomes are extracellular vesicles that are important mediators of intercellular communication and play a role in promoting angiogenesis. However, very little is known about the contribution of breast cancer exosomes to tumor angiogenesis or whether exosomes can mediate DHA’s anticancer action. Results: Exosomes were collected from MCF7 and MDA-MB-231 breast cancer cells after treatment with DHA. We observed an increase in exosome secretion and exosome microRNA contents from the DHA-treated cells. The expression of 83 microRNAs in the MCF7 exosomes was altered by DHA (>2-fold). The most abundant exosome microRNAs (let-7a, miR-23b, miR-27a/b, miR-21, let-7, and miR-320b) are known to have anti-cancer and/or anti-angiogenic activity. These microRNAs were also increased by DHA treatment in the exosomes from other breast cancer lines (MDA-MB-231, ZR751 and BT20), but not in exosomes from normal breast cells (MCF10A). When DHA-treated MCF7 cells were co-cultured with or their exosomes were directly applied to endothelial cell cultures, we observed an increase in the expression of these microRNAs in the endothelial cells. Furthermore, overexpression of miR-23b and miR-320b in endothelial cells decreased the expression of their pro-angiogenic target genes (PLAU, AMOTL1, NRP1 and ETS2) and significantly inhibited tube formation by endothelial cells, suggesting that the microRNAs transferred by exosomes mediate DHA’s anti-angiogenic action. These effects could be reversed by knockdown of the Rab GTPase, Rab27A, which controls exosome release. Conclusions: We conclude that DHA alters breast cancer exosome secretion and microRNA contents, which leads to the inhibition of angiogenesis. Our data demonstrate that breast cancer exosome signaling can be targeted to inhibit tumor angiogenesis and provide new insight into DHA’s anticancer action, further supporting its use in cancer therapy. Examination of small RNA populations in MCF7 cells and exosomes after DHA treatment.

Project description:Background: Docosahexaenoic acid (DHA) is a natural compound with anticancer and anti-angiogenesis activity that is currently under investigation as both a preventative agent and an adjuvant to breast cancer therapy. However, the precise mechanisms of DHA’s anticancer activities are unclear. It is understood that the intercommunication between cancer cells and their microenvironment is essential to tumor angiogenesis. Exosomes are extracellular vesicles that are important mediators of intercellular communication and play a role in promoting angiogenesis. However, very little is known about the contribution of breast cancer exosomes to tumor angiogenesis or whether exosomes can mediate DHA’s anticancer action. Results: Exosomes were collected from MCF7 and MDA-MB-231 breast cancer cells after treatment with DHA. We observed an increase in exosome secretion and exosome microRNA contents from the DHA-treated cells. The expression of 83 microRNAs in the MCF7 exosomes was altered by DHA (>2-fold). The most abundant exosome microRNAs (let-7a, miR-23b, miR-27a/b, miR-21, let-7, and miR-320b) are known to have anti-cancer and/or anti-angiogenic activity. These microRNAs were also increased by DHA treatment in the exosomes from other breast cancer lines (MDA-MB-231, ZR751 and BT20), but not in exosomes from normal breast cells (MCF10A). When DHA-treated MCF7 cells were co-cultured with or their exosomes were directly applied to endothelial cell cultures, we observed an increase in the expression of these microRNAs in the endothelial cells. Furthermore, overexpression of miR-23b and miR-320b in endothelial cells decreased the expression of their pro-angiogenic target genes (PLAU, AMOTL1, NRP1 and ETS2) and significantly inhibited tube formation by endothelial cells, suggesting that the microRNAs transferred by exosomes mediate DHA’s anti-angiogenic action. These effects could be reversed by knockdown of the Rab GTPase, Rab27A, which controls exosome release. Conclusions: We conclude that DHA alters breast cancer exosome secretion and microRNA contents, which leads to the inhibition of angiogenesis. Our data demonstrate that breast cancer exosome signaling can be targeted to inhibit tumor angiogenesis and provide new insight into DHA’s anticancer action, further supporting its use in cancer therapy.

Project description:Background: Angiogenesis is an essential step for tissue development and its dysregulation is associated with various diseases, including moyamoya disease. Among the regulators of angiogenesis, galectin-1 encoded by LGALS1, plays essential roles, but the underlying mechanisms need to be further expounded. In this study, we systematically investigated the potential targets of galectin-1 by silencing LGALS1 (siLGALS1) in human umbilical vein endothelial cells (HUVECs) and performing whole transcriptome sequencing (RNA-seq) experiments. We also integrated galectin-1-interacting RNA data to explore how galectin-1 regulates gene expression and alternative splicing. Results: By systematical analysis, we found siLGALS1 treatment significantly regulated 1451 differentially expressed genes (DEGs), including 604 up-regulated DEGs and 847 down-regulated DEGs. The down-regulated DEGs were significantly enriched in angiogenesis and inflammatory response pathways. The involved genes included CCL2, GJA5, CALCRL, ACKR3, HEY1, AQP1, CD34, ECM1, RAMP2, and SELP, which were also validated by RT-qPCR experiment. We also analyzed the dysregulated alternative splicing (AS) profile by siLGALS1, and found siLGALS1 had obvious bias for dysregulated AS types, preferring to promote exon skipping and intron retention, and inhibit cassette exon events. Interestingly, we found the regulated AS genes (RASGs) were enriched in focal adhesion and VEGF signaling pathway, which were highly related to angiogenesis. Finally, we found hundreds of RASGs were also bound by galectin-1 using the published iRIP-seq data of galectin-1, including RASGs from angiogenesis pathway. Conclusions: In summary, our results demonstrated that galectin-1 could regulate angiogenesis-related genes at transcriptional and post-transcriptional levels, which is associated its RNA binding ability in HUVECs. The discovery extends our understanding on the functions and molecular mechanisms of galectin-1 during the development of angiogenesis, which could be served as a therapeutic option in anti-angiogenic treatment in future.

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