MRTF-A and STAT3 synergistically promote breast cancer cell migration

Breast cancer is the leading cause of cancer death in women worldwide which is closely related to metastasis. But the exact molecular mechanism on metastasis is still not fully understood; we now report that both MRTF-A and STAT3 play important role in breast cancer migration of MDA-MB-231 cells. Moreover, MRTF-A and STAT3 synergistically increased MDA-MB-231 cell migration by promoting the expression of migration markers Myl-9 and Cyr-61. Importantly, we identified a detailed molecular mechanism of MDA-MB-231 cell migration controlled via physical interaction between MRTF-A and STAT3, which synergistically promote the transactivity of the migration marker Myl-9 and Cyr-61 by CArG box binding. Interestingly, the two signaling pathways RhoA-MRTF-A and JAK-STAT3 across talk to regulate MDA-MB-231 cell migration. Our data thus provide important and novel insights into the roles of MRTF-A and STAT3 in regulating MDA-MB-231 cell migration.     

Adipose-derived stem cells and cancer cells fuse to generate cancer stem cell-like cells with increased tumorigenicity

Adipose-derived stem cells (ADSCs) are a type of mesenchymal stem cells isolated from adipose tissue and have the ability to differentiate into adipogenic, osteogenic, and chondrogenic lineages. Despite their great therapeutic potentials, previous studies showed that ADSCs could enhance the proliferation and metastatic potential of breast cancer cells (BCCs). In this study, we found that ADSCs fused with BCCs spontaneously, while breast cancer stem cell (CSC) markers CD44⁺CD24^-/lowEpCAM⁺ were enriched in this fusion population. We further assessed the fusion hybrid by multicolor DNA FISH and mouse xenograft assays. Only single nucleus was observed in the fusion hybrid, confirming that it was a synkaryon. In vivo mouse xenograft assay indicated that the tumorigenic potential of the fusion hybrid was significantly higher than that of the parent tumorigenic triple-negative BCC line MDA-MB-231. We had compared the fusion efficiency between two BCC lines, the CD44-rich MDA-MB-231 and the CD44-poor MCF-7, with ADSCs. Interestingly, we found that the fusion efficiency was much higher between MDA-MB-231 and ADSCs, suggesting that a potential mechanism of cell fusion may lie in the dissimilarity between these two cell lines. The cell fusion efficiency was hampered by knocking down the CD44. Altogether, our findings suggest that CD44-mediated cell fusion could be a potential mechanism for generating CSCs.     

Specific expression of the human voltage-gated proton channel Hv1 in highly metastatic breast cancer cells, promotes tumor progression and metastasis

The newly discovered human voltage-gated proton channel Hv1 is essential for proton transfer, which contains a voltage sensor domain (VSD) without a pore domain. We report here for the first time that Hv1 is specifically expressed in the highly metastatic human breast tumor tissues, but not in poorly metastatic breast cancer tissues, detected by immunohistochemistry. Meanwhile, real-time RT-PCR and immunocytochemistry showed that the expression levels of Hv1 have significant differences among breast cancer cell lines, MCF-7, MDA-MB-231, MDA-MB-468, MDA-MB-453, T-47D and SK-BR-3, in which Hv1 is expressed at a high level in highly metastatic human breast cancer cell line MDA-MB-231, but at a very low level in poorly metastatic human breast cancer cell line MCF-7. Inhibition of Hv1 expression in the highly metastatic MDA-MB-231 cells by small interfering RNA (siRNA) significantly decreases the invasion and migration of the cells. The intracellular pH of MDA-MB-231 cells down-regulated Hv1 expression by siRNA is obviously decreased compared with MDA-MB-231 with the scrambled siRNA. The expression of matrix metalloproteinase-2 and gelatinase activity in MDA-MB-231 cells suppressed Hv1 by siRNA were reduced. Our results strongly suggest that Hv1 regulates breast cancer intracellular pH and exacerbates the migratory ability of metastatic cells.     

Different anticancer effects of Saxifragifolin A on estrogen receptor-positive and estrogen receptor-negative breast cancer cells

BackgroundBreast cancer is the leading cause of cancer-related death among women worldwide. For treating breast cancer, numerous natural products have been considered as chemotherapeutic drugs.Hypothesis/purposeThe present study aims to investigate the apoptotic effect of Saxifragifolin A (Saxi A) isolated from Androsace umbellata in two different human breast cancer cells which are ER-positive MCF-7 cells and ER-negative MDA-MB-231 cells, and examine the molecular basis for its anticancer actions.Study designThe inhibitory effects of Saxi A on cell survival were examined in MCF-7 cells and MDA-MB-231 cells in vitro.MethodsMTT assays, Annexin V/PI staining analysis, ROS production assay, Hoechst33342 staining and Western blot analysis were performed.ResultsOur results showed that MDA-MB-231 cells were more sensitive to Saxi A-induced apoptosis than MCF-7 cells. Saxi A induced apoptosis in MDA-MB-231 cells through ROS-mediated and caspase-dependent pathways, whereas treatment with Saxi A induced apoptosis in MCF-7 cells in a caspase-independent manner. In spite of Saxi A-induced activation of MAPKs in both breast cancer cell lines, only p38 MAPK and JNK mediated Saxi A-induced apoptosis. In addition, cell survival of shERα-transfected MCF-7 cells was decreased, while MDA-MB-231 cells that overexpress ERα remained viable.ConclusionSaxi A inhibits cell survival in MCF-7 cells and MDA-MB-231 cells through different regulatory pathway, and ERα status appears to be important for regulating Saxi A-induced apoptosis in breast cancer cells. Thus, Saxi A may have a potential therapeutic use for treating breast cancer.     

BIOCOCKTAIL对乳腺癌细胞MDA-MB-231凋亡的促进作用

目的从细胞凋亡方面观察BIOCOCKTAIL（益生菌微生物制剂）对乳腺癌细胞MDA-MB-231的抑制作用。方法采用FITC和PI双染色法及TUNEL法检测凋亡。结果通过FITC和PI双染色法,观察到BIOCOCKTAIL可显著增加乳腺癌细胞MDA-MB一231凋亡细胞。I组乳腺癌细胞系（8．1％绑38．7％,P〈0．05）,Ⅱ组乳腺癌细胞系（6．9％掷19．4％,P〈0．05）。TUNEL法检测MDA-MB-231细胞凋亡现象明显增多。结论BIOCOCKTAIL能够有效诱导乳腺癌细胞MDA-MB-231凋亡,有可能成为乳腺癌治疗的补充方案。     

Progranulin stimulated by LPA promotes the migration of aggressive breast cancer cells

Activator and inhibitor roles for the 88-kDa-secreted glycoprotein progranulin (PGRN) have been demonstrated in ovarian cancer cells. Here, we investigated the effects of PGRN in breast cancer migration. Testing MCF7, MDA-MB-453, and MDA-MB-231 human breast cancer cells and the MCF10A breast epithelial cell line, we demonstrate that LPA-induced PGRN stimulation led to a significant increase in cell invasion of MDA-MB-453 and MDA-MB-231 cells only (p<0.05). Moreover, incubation with an anti-PGRN antibody, an inhibitor of the ERK pathway (PD98059) or both in combination inhibited the ability of MDA-MB-231 cells to invade. Furthermore, the expression of focal adhesion kinases promoted by LPA-induced PGRN was also inhibited by PD98059 alone or in combination with an anti-PGRN antibody (p<0.05). Taken together, these results suggest that the LPA activation of PGRN involving the ERK pathway is critical to promote MDA-MB-231 breast cancer cell invasion.     

人间充质干细胞对乳腺癌细胞生长的影响研究

目的通过构建间充质干细胞(MSC)与乳腺癌细胞间相互作用的共培养模型,探讨MSC对乳腺癌细胞生长的影响。方法用含荧光基因第三代自身失活慢病毒载体感染人类脐带分离提取的MSC和乳腺癌细胞MDA-MB-231、MCF-7,以单独培养的乳腺癌细胞MDA-MB-231和MCF-7分别设立对照,2种乳腺癌细胞分别与MSC共培养,检测乳腺癌细胞在MSC作用下增生能力的改变,流式细胞术检测共培养后细胞表面标记物表达。两组间比较采用独立样本t检验,多组间比较采用单因素方差分析,多重比较采用Dunnet-t检验。结果MSC在与乳腺癌细胞共培养过程中促进肿瘤细胞生长,第3天共培养组乳腺癌MDA-MB-231细胞数高于单独MDA-MB-231培养组[(5.50±0.71)×10^3个比(1.63±0.41)×10^3个],培养至第7天,两组间MDA-MB-231细胞数差异进一步增大[(81.25±7.40)×10^3个比(26.25±4.15)×10^3个],差异具有统计学意义(P均<0.001);共培养后MSC促进乳腺癌细胞表达干细胞特有标记物CD90,MCF-7从共培养第2天CD90表达率(1.38±0.30)﹪升高至第9天(92.45±2.04)﹪。在共培养中MSC围绕肿瘤细胞集落方式生长,在形态上变长,并发现一种新型混合细胞(hybrid融合细胞)同时表达绿色和红色荧光,且对化疗药物更敏感。结论MSC促进乳腺癌细胞的生长,伴随MSC形态学改变和hybrid融合细胞出现,乳腺癌细胞获得MSC特有CD90表达。     

6]-Gingerol inhibits metastasis of MDA-MB-231 human breast cancer cells

Gingerol (Zingiber officinale Roscoe, Zingiberaceae) is one of the most frequently and heavily consumed dietary condiments throughout the world. The oleoresin from rhizomes of ginger contains [6]-gingerol (1-[4′-hydroxy-3′-methoxyphenyl]-5-hydroxy-3-decanone) and its homologs which are pungent ingredients that have been found to possess many interesting pharmacological and physiological activities, such as anti-inflammatory, antihepatotoxic and cardiotonic effects. However, the effects of [6]-gingerol on metastatic processes in breast cancer cells are not currently well known. Therefore, in this study, we examined the effects of [6]-gingerol on adhesion, invasion, motility, activity and the amount of MMP-2 or -9 in the MDA-MB-231 human breast cancer cell line. We cultured MDA-MB-231 cells in the presence of various concentrations of [6]-gingerol (0, 2.5, 5 and 10 μM). [6]-Gingerol had no effect on cell adhesion up to 5 μM, but resulted in a 16% reduction at 10 μM. Treatment of MDA-MB-231 cells with increasing concentrations of [6]-gingerol led to a concentration-dependent decrease in cell migration and motility. The activities of MMP-2 or MMP-9 in MDA-MB-231 cells were decreased by treatment with [6]-gingerol and occurred in a dose-dependent manner. The amount of MMP-2 protein was decreased in a dose-dependent manner, although there was no change in the MMP-9 protein levels following treatment with [6]-gingerol. MMP-2 and MMP-9 mRNA expression were decreased by [6]-gingerol treatment. In conclusion, we have shown that [6]-gingerol inhibits cell adhesion, invasion, motility and activities of MMP-2 and MMP-9 in MDA-MB-231 human breast cancer cell lines.     

Cdc42 negatively regulates intrinsic migration of highly aggressive breast cancer cells

The small GTPase Cdc42 has been implicated as an important regulator of cell migration. However, whether Cdc42 plays similar role in all cancer cells irrespective of metastatic potential remains poorly defined. Here, we show by using three different breast cancer cell lines with different metastatic potential, the role of Cdc42 in cell migration/invasion and its relationship with a number of downstream signaling pathways controlling cell migration. Small interfering RNA (siRNA)-mediated knockdown of Cdc42 in two highly metastatic breast cancer cell lines (MDA-MB-231 and C3L5) resulted in enhancement, whereas the same in moderately metastatic (Hs578T) cell line resulted in inhibition of intrinsic cellular migration/invasion. Furthermore, Cdc42 silencing in MDA-MB-231 and C3L5 but not Hs578T cells was shown to be accompanied by increased RhoA activity and phosphorylation of protein kinase C (PKC)-δ, extracellular signal regulated kinase1/2 (Erk1/2), and protein kinase A (PKA). Pharmacological inhibition of PKCδ, MEK-Erk1/2, or PKA was shown to inhibit migration of both control and Cdc42-silenced MDA-MB-231 cells. Furthermore, introduction of constitutively active Cdc42 was shown to decrease migration/invasion of MDA-MB-231 and C3L5 but increase migration/invasion of Hs578T cells. This decreased migration/invasion of MDA-MB-231 and C3L5 cells was also shown to be accompanied by the decrease in the phosphorylations of PKCδ, Erk1/2, and PKA. These results suggested that endogenous Cdc42 could exert a negative regulatory influence on intrinsic migration/invasion and some potentially relevant changes in phosphorylation of PKCδ, Erk1/2, and PKA of some aggressive breast cancer cells.