Crosstalk between osteoprotegerin (OPG), fatty acid synthase (FASN) and, cycloxygenase-2 (COX-2) in breast cancer: implications in carcinogenesis.
Crosstalk between osteoprotegerin (OPG), fatty acid synthase (FASN) and, cycloxygenase-2 (COX-2) in breast cancer: implications in carcinogenesis.
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DOI：
10.18632/oncotarget.9835
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发表时间：
2016-09-13
期刊：
影响因子：
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通讯作者：
Sharma-Walia N
中科院分区：
文献类型：
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作者：
Goswami S;Sharma-Walia N
在细胞因子/趋化因子的操纵下，肿瘤微环境中的恶性和非恶性细胞之间的串扰推动了乳腺癌的进展。在我们之前的研究中，我们发现骨保护素(OPG)是乳腺癌细胞大量分泌的细胞因子之一。与正常乳腺上皮HMEC细胞相比，高侵袭性乳腺癌细胞株SUM149PT和SUM1315MO2表达和分泌OPG的水平非常高。OPG参与调控乳腺癌的非整倍体、细胞增殖和血管生成。在这项研究中进行的质谱分析表明，OPG与脂肪酸合成酶(FASN)相互作用，FASN是乳腺癌细胞脂肪酸生物合成途径的关键酶。此外，电子显微镜、免疫荧光和荧光定量分析表明，与HMEC相比，SUM149PT和SUM1315MO2细胞中存在大量的脂体(脂滴)。我们最近发现，在SUM149PT和SUM1315MO2乳腺癌细胞中，COX-2炎症通路及其代谢物PGE2分泌上调。有趣的是，人类乳腺癌组织样本显示出OPG、PGE2和脂肪酸合成酶(FASN)的高表达。FASN是一种参与脂质生物合成的多功能酶。免疫荧光染色显示COX-2和FASN在乳腺癌细胞的脂体中共存。我们推测OPG、FASN和COX-2之间可能存在串扰，从而维持乳腺癌的炎症通路。有趣的是，通过CRISPR/Cas9基因编辑敲除乳腺癌细胞中的OPG，在蛋白质水平上降低了FASN的表达。在此，我们确定了参与重组人OPG(RhOPG)对COX-2和FASN转录调控的顺式作用元件。FASN抑制剂C75和COX-2抑制剂塞来昔布分别减少细胞内脂质小体数目，下调ERK、GSK3β的磷酸化，并通过激活caspase-3/7和caspase-9诱导细胞凋亡。但在联合治疗侵袭性癌细胞时，观察到更有效的脂体/细胞和存活激酶信号的减少。总的来说，OPG、FASN和COX-2之间的新的生物串扰倡导联合药物治疗，以阻断这些致癌因素，作为治疗高侵袭性乳腺癌的有前景的治疗靶点。
The crosstalk between malignant and nonmalignant cells in the tumor microenvironment, as maneuvered by cytokines/chemokines, drives breast cancer progression. In our previous study, we discovered Osteoprotegerin (OPG) as one of the cytokines heavily secreted by breast cancer cells. We demonstrated that OPG is expressed and secreted at very high levels from the highly invasive breast cancer cell lines SUM149PT and SUM1315MO2 as compared to normal human mammary epithelial HMEC cells. OPG was involved in modulating aneuploidy, cell proliferation, and angiogenesis in breast cancer. Mass spectrometry analysis performed in this study revealed OPG interacts with fatty acid synthase (FASN), which is a key enzyme of the fatty acid biosynthetic pathway in breast cancer cells. Further, electron microscopy, immunofluorescence, and fluorescence quantitation assays highlighted the presence of a large number of lipid bodies (lipid droplets) in SUM149PT and SUM1315MO2 cells in comparison to HMEC. We recently showed upregulation of the COX-2 inflammatory pathway and its metabolite PGE2 secretion in SUM149PT and SUM1315MO2 breast cancer cells. Interestingly, human breast cancer tissue samples displayed high expression of OPG, PGE2 and fatty acid synthase (FASN). FASN is a multifunctional enzyme involved in lipid biosynthesis. Immunofluorescence staining revealed the co-existence of COX-2 and FASN in the lipid bodies of breast cancer cells. We reasoned that there might be crosstalk between OPG, FASN, and COX-2 that sustains the inflammatory pathways in breast cancer. Interestingly, knocking down OPG by CRISPR/Cas9 gene editing in breast cancer cells decreased FASN expression at the protein level. Here, we identified cis-acting elements involved in the transcriptional regulation of COX-2 and FASN by recombinant human OPG (rhOPG). Treatment with FASN inhibitor C75 and COX-2 inhibitor celecoxib individually decreased the number of lipid bodies/cell, downregulated phosphorylation of ERK, GSK3β, and induced apoptosis by caspase-3/7 and caspase-9 activation. But a more efficient and effective decrease in lipid bodies/cell and survival kinase signaling was observed upon combining the drug treatments for the aggressive cancer cells. Collectively, the novel biological crosstalk between OPG, FASN, and COX-2 advocates for combinatorial drug treatment to block these players of carcinogenesis as a promising therapeutic target to treat highly invasive breast cancer.