MiRNA-101 inhibits breast cancer growth and metastasis by targeting CX chemokine receptor 7

Whereas miR-101 is involved in the development and progression of breast cancer, the underlying molecular mechanisms remain to be elucidated. Here, we report that miR-101 expression is inversely correlated with the clinical stage, lymph node metastasis and prognosis in breast cancers. Introduction of miR-101 inhibited breast cancer cell proliferation and invasion in vitro and suppressed tumor growth and lung metastasis of in vivo. CX chemokine receptor 7 (CXCR7) is a direct target of miR-101, positively correlating with the histological grade and the incidence of lymph node metastasis in breast cancer patients. The effects of miR-101 were mimicked and counteracted by CXCR7 depletion and overexpression, respectively. STAT3 signaling downstream of CXCR7 is involved in miR-101 regulation of breast cancer cell behaviors. These findings have implications for the potential application of miR-101 in breast cancer treatment.     

Calsequestrin 2 overexpression in breast cancer increases tumorigenesis and metastasis by modulating the tumor microenvironment

The spatial tumor shape is determined by the complex interactions between tumor cells and their microenvironment. Here, we investigated the role of a newly identified breast cancer‐related gene, calsequestrin 2 (CASQ2), in tumor–microenvironment interactions during tumor growth and metastasis. We analyzed gene expression and three‐dimensional tumor shape data from the breast cancer dataset of The Cancer Genome Atlas (TCGA) and identified CASQ2 as a potential regulator of tumor–microenvironment interaction. In TCGA breast cancer cases containing information of three‐dimensional tumor shapes, CASQ2 mRNA showed the highest correlation with the spatial tumor shapes. Furthermore, we investigated the expression pattern of CASQ2 in human breast cancer tissues. CASQ2 was not detected in breast cancer cell lines in vitro but was induced in the xenograft tumors and human breast cancer tissues. To evaluate the role of CASQ2, we established CASQ2‐overexpressing breast cancer cell lines for in vitro and in vivo experiments. CASQ2 overexpression in breast cancer cells resulted in a more aggressive phenotype and altered epithelial–mesenchymal transition (EMT) markers in vitro. CASQ2 overexpression induced cancer‐associated fibroblast characteristics along with increased hypoxia‐inducible factor 1α (HIF1α) expression in stromal fibroblasts. CASQ2 overexpression accelerated tumorigenesis, induced collagen structure remodeling, and increased distant metastasis in vivo. CASQ2 conferred more metaplastic features to triple‐negative breast cancer cells. Our data suggest that CASQ2 is a key regulator of breast cancer tumorigenesis and metastasis by modulating diverse aspects of tumor–microenvironment interactions.     

The chemokine receptor CCR4 promotes tumor growth and lung metastasis in breast cancer

Increasing evidence has shown that chemokines and chemokine receptors are associated with tumor growth and metastasis. CCR4, an important chemokine receptor for regulating immune homeostasis, is thought to be involved in hematologic malignancies and has also recently implicated in some solid tumors, such as gastric cancer. The possible role of CCR4 in breast cancer has not been well elucidated. In this study, we show that CCR4 is differentially expressed in human breast cancer cell lines. Specifically, we find that CCR4 is overexpressed in breast cancer cell lines with high metastatic potential. More importantly, we used a combination of overexpression and RNA interference to demonstrate that CCR4 promotes breast tumor growth and lung metastasis in mice. Furthermore, we find that microvessel density is significantly increased in tumors formed by CCR4-overexpressing cells and decreased in those formed by CCR4-knockdown cells. We find that overexpression of CCR4 can enhance the chemotactic response of breast cancer cells to CCL17. However, the expression of CCR4 does not affect the proliferation of breast cancer cells in vitro. Furthermore, we show that CCR4 expression is positively correlated with HER2 expression, tumor recurrence and lymph node, lung and bone metastasis (P < 0.05). Multivariate analysis showed that CCR4 expression is a significant independent prognostic factor for overall survival (P = 0.036) but not for disease-free survival in patients with breast cancer (P = 0.071). Survival analysis indicated a strong association between CCR4 expression and lower overall survival (P = 0.0001) and disease-free survival (P = 0.016) in breast cancer.     

Insulin-like growth factor receptor signaling in breast tumor epithelium protects cells from endoplasmic reticulum stress and regulates the tumor microenvironment

Background

Early analyses of human breast cancer identified high expression of the insulin-like growth factor type 1 receptor (IGF-1R) correlated with hormone receptor positive breast cancer and associated with a favorable prognosis, whereas low expression of IGF-1R correlated with triple negative breast cancer (TNBC). We previously demonstrated that the IGF-1R acts as a tumor and metastasis suppressor in the Wnt1 mouse model of TNBC. The mechanisms for how reduced IGF-1R contributes to TNBC phenotypes is unknown.

Methods

We analyzed the METABRIC dataset to further stratify IGF-1R expression with patient survival and specific parameters of TNBC. To investigate molecular events associated with the loss of IGF-1R function in breast tumor cells, we inhibited IGF-1R in human cell lines using an IGF-1R blocking antibody and analyzed MMTV-Wnt1-mediated mouse tumors with reduced IGF-1R function through expression of a dominant-negative transgene.

Results

Our analysis of the Molecular Taxonomy of Breast Cancer International Consortium (METABRIC) dataset revealed association between low IGF-1R and reduced overall patient survival. IGF-1R expression was inversely correlated with patient survival even within hormone receptor-positive breast cancers, indicating reduced overall patient survival with low IGF-1R was not due simply to low IGF-1R expression within TNBCs. Inhibiting IGF-1R in either mouse or human tumor epithelial cells increased reactive oxygen species (ROS) production and activation of the endoplasmic reticulum stress response. IGF-1R inhibition in tumor epithelial cells elevated interleukin (IL)-6 and C-C motif chemokine ligand 2 (CCL2) expression, which was reversed by ROS scavenging. Moreover, the Wnt1/dnIGF-1R primary tumors displayed a tumor-promoting immune phenotype. The increased CCL2 promoted an influx of CD11b⁺ monocytes into the primary tumor that also had increased matrix metalloproteinase (MMP)-2, MMP-3, and MMP-9 expression. Increased MMP activity in the tumor stroma was associated with enhanced matrix remodeling and collagen deposition. Further analysis of the METABRIC dataset revealed an increase in IL-6, CCL2, and MMP-9 expression in patients with low IGF-1R, consistent with our mouse tumor model and data in human breast cancer cell lines.

Conclusions

Our data support the hypothesis that reduction of IGF-1R function increases cellular stress and cytokine production to promote an aggressive tumor microenvironment through infiltration of immune cells and matrix remodeling.

     

趋化因子CXCL12及其受体CXCR4介导乳腺癌转移分子机制

趋化因子CXCL12及其受体CXCR4之间的相互作用在乳腺癌转移中起着枢轴作用.新近研究发现,CXCR4-CXCL12介导的乳腺癌转移与缺氧诱导因子-1(HIF-1)、Her-2、核因子-κB(NFκB)、尿激酶型纤维蛋白酶原激活剂受体(uPAR)等分子密切相关,明确CXCL12-CXCR4介导的乳腺癌转移分子机制,进而逐个阻断上游分子对二者的调控作用,开发出靶点明确、作用特异的抗转移药物将使乳腺癌患者获益.     

微环境中间质细胞通过趋化因子对乳腺癌生长和转移的影响

摘 要 大量研究表明，微环境中的多种间质细胞对肿瘤细胞的生长和转移具有多方面的影响，而在此过程中趋化因子及其受体则发挥着至关重要的作用。乳腺癌中的肿瘤相关性巨噬细胞在趋化因子CCL2及其受体CCR2作用下向肿瘤部位大量聚集，发挥促肿瘤血管形成的作用；癌症相关性成纤维细胞通过CXCL12/CXCR4生物轴作用于乳腺癌细胞，促进肿瘤生长和转移；间充质干细胞以旁分泌的方式分泌CCL5，作用于CCR5阳性的乳腺癌细胞，增强肿瘤细胞的运动、浸润和转移能力。除此之外，骨髓来源的细胞、造血前驱细胞、肿瘤浸润性树突状细胞、肿瘤浸润性淋巴细胞以及其他白细胞也能借助趋化因子及其受体在肿瘤微环境中发挥着重要作用。由此可见，对肿瘤微环境中间质细胞及趋化因子的深入研究，可能为肿瘤的生物学治疗提供新的靶点。     

趋化因子CXCL12及其受体与肿瘤转移的关系

趋化因子CXCL12(C-X-C chemokine ligand 12)及其受体CXCR4(c-x-c chemokine receptor4)在胚胎发育、干细胞的迁移和各种免疫反应中发挥重要作用,是许多生理和病理过程中指导细胞运动的中心因素.最近发现肿瘤细胞的转移机制和白细胞的迁移相类似,趋化因子CXCL12及其受体与肿瘤的生长、侵袭、转移和分泌密切相关,动物实验表明CXCR4可能成为抑制肿瘤生长、转移的重要靶目标.本文将对趋化因子CXCL12及其受体CXCR4在肿瘤转移、进展中的作用以及与此相关的信号转导、调节因子进行综述.     

AGPAT9 suppresses cell growth,invasion and metastasis by counteracting acidic tumor microenvironment through KLF4/LASS2/V-ATPase signaling pathway in breast cancer

Human 1-acylglycerol-3-phosphate O-acyltransferase 9 (AGPAT9) is the gene identified from adipose tissue in 2007. We found AGPAT9 expression was significantly higher in poorly invasive MCF7 human breast cancer cells than the highly invasive MDA-MB-231 cells. AGPAT9 significantly inhibited the proliferation of breast cancer cells in vitro and in vivo. Live-cell imaging and transwell assays showed that AGPAT9 could significantly inhibit the migration and invasive capacities of breast cancer cells. The inhibitory effect of AGPAT9 on metastasis was also observed in vivo in lung metastasis model. AGPAT9 inhibited breast cancer cell proliferation, migration and invasion through, at least in part, suppressing the V-ATPase activity. In addition, increased AGPAT9 expression in MCF-7/ADR cells could increase the chemosensitivity to doxorubicin (Dox). Our findings suggest that increasing AGPAT9 expression may be a new approach that can be used for breast cancer treatment.     

胰腺癌组织中CXCR7的表达与其临床病理特征的关系

目的：探讨CXCR7在人胰腺癌组织中的表达及与临床病理特征之间的关系。方法：应用免疫组织化学方法检测64例胰腺癌组织及24例正常组织中CXCR7的表达。结果：胰腺癌组织的CXCR7表达在是否淋巴结转移之间有显著差异（P〈0.05）。结论：CXCR7与胰腺癌的侵袭转移密切相关,有可能作为治疗胰腺癌的新靶点。     

Yanhusuo extract inhibits metastasis of breast cancer cells by modulating mitogen-activated protein kinase signaling pathways

Yanhusuo (Corydalis yanhusuo W.T. Wang) is a well-known traditional Chinese medicine (TCM). In this study, we attempted to characterize in detail the signaling cascades that produce its anti-metastatic effect on the human breast cancer cell line, MDA-MB-231. We found that the yanhusuo extract inhibited the migration and invasion of MDA-MB-231 cells in vitro. In addition, the yanhusuo extract inhibited the mRNA expression and activity of metalloproteinase-9 (MMP-9). The anti-cancer metastasis effect of yanhusuo involved the activation of p38 and inhibition of ERK1/2 and SAPK/JNK mitogen-activated protein kinase (MAPK) signaling. Our experiments identified the biological activity of yanhusuo against cancer metastasis in vitro and provide a rationale for its further investigation.     

Src inhibitor dasatinib inhibits growth of breast cancer cells by modulating EGFR signaling

EGF-receptor family members (EGFRs) as well as c-Src are over expressed in 70% of breast cancer, and in most of the tumors c-Src is co-over expressed with at least one of the EGFRs, suggesting that they may interact functionally and play a role in the development and progression of the malignancy. We hypothesize that a small molecule inhibitor of c-Src dasatinib (BMS-354825; Bristol Myers Squibb), exerts its effects on breast cancer cells by modulating EGFR signaling. Indeed, we found that dasatinib causes inhibition of breast cancer cells overexpressing EGFR, HER-2 and HER-3 (MDA-MB-468, SKBR3, MDA-MB-453, and MDA-MB-231) in a dose and time-dependent manner. Dasatinib also stimulated apoptosis in MDA-MB-468 cells, which could be attributed to activation of both caspase-9 and -8 and arrest of the cell cycle at G₀/G₁ cycle. Furthermore, dasatinib markedly inhibited colony formation, cell invasion, migration and angiogenesis, accompanied by decreased phosphorylation of EGFR and c-Src and their downstream effector molecules Akt and Erks. Our data suggest that dasatinib mediates its action in part through EGFR signaling and could be a potential therapeutic agent for breast cancer.     

Ron receptor signaling augments mammary tumor formation and metastasis in a murine model of breast cancer

The tyrosine kinase receptor Ron has been implicated in several types of cancer, including overexpression in human breast cancer. This is the first report describing the effect of Ron signaling on tumorigenesis and metastasis in a mouse model of breast cancer. Mice with a targeted deletion of the Ron tyrosine kinase signaling domain (TK-/-) were crossed to mice expressing the polyoma virus middle T antigen (pMT) under the control of the mouse mammary tumor virus promoter. Both pMT-expressing wild-type control (pMT+/- TK+/+) and pMT+/- TK-/- mice developed mammary tumors and lung metastases. However, a significant decrease in mammary tumor initiation and growth was found in the pMT+/- TK-/- mice compared with controls. An examination of mammary tumors showed that there was a significant decrease in microvessel density, significantly decreased cellular proliferation, and a significant increase in terminal deoxynucleotidyl transferase-mediated nick end labeling-positive staining in mammary tumor cells from the pMT+/- TK-/- mice compared with the pMT+/- TK+/+ mice. Biochemical analyses on mammary tumor lysates showed that whereas both the pMT-expressing TK+/+ and TK-/- tumors have increased Ron expression compared with normal mammary glands, the pMT-expressing TK-/- tumors have deficits in mitogen-activated protein kinase and AKT activation. These results indicate that Ron signaling synergizes with pMT signaling to induce mammary tumor formation, growth, and metastasis. This effect may be mediated in part through the regulation of angiogenesis and through proliferative and cell survival pathways regulated by mitogen-activated protein kinase and AKT.     

MicroRNA let-7a suppresses breast cancer cell migration and invasion through downregulation of C-C chemokine receptor type 7

Introduction  

C-C chemokine receptor type 7 (CCR7) plays an important role in chemotactic and metastatic responses in various cancers, including breast cancer. In the present study, the authors demonstrated that microRNA (miRNA) let-7a downregulates CCR7 expression and directly influences the migration and invasion of breast cancer cells.     

Role of estrogen receptor alpha in modulating IGF-I receptor signaling and function in breast cancer

The insulin-like growth factor I (IGF-I) receptor (IGF-IR) is a multifunctional transmembrane tyrosine kinase that has been implicated in neoplastic transformation. The tumorigenic potential of IGF-IR relies on its strong anti-apoptotic and mitogenic activity. The growth and survival signals of IGF-IR are mediated through multiple intracellular pathways, many of which emanate from insulin receptor substrate 1 (IRS-1). In hormone-dependent breast cancer cells, IGF-IR and IRS-1 are often co-expressed with the estrogen receptor alpha (ERalpha), and IGF-I and ER systems are engaged in a powerful functional cross-talk. Most notably, activation of ERalpha upregulates the expression of IRS-1, IGF-IR, and IGF-1, which results in amplification of IGF-I responses. Reciprocally, stimulation of IGF-IR increases the phosphorylation and activity of ERalpha. In contrast, in ERalpha-negative breast cancer cells and tumors, the levels of IGF-IR and IRS-1 are often decreased and IGF-I is non-mitogenic. Our data suggest that defective IGF-IR signaling in ERalpha-negative cells is related, at least in part, to improper activation of the IRS-1/PI-3K/Akt/GSK-3 pathway and lack of Rb1 phosphorylation. These defects are partially reversed by re-expression of ERalpha. Interestingly, some non-mitogenic IGF-I responses, such as migration and invasion are retained in the absence of ERalpha, suggesting that IGF-IR function in breast cancer cells might depend on the ERalpha status. The understanding of how ERalpha may dictate IGF-I responses will help in devising rational anti-IGF-IR strategies for breast cancer treatment.     

MicroRNA-34a regulates WNT/TCF7 signaling and inhibits bone metastasis in Ras-activated prostate cancer

Aberrant activation of Ras and WNT signaling are key events that have been shown to be up-regulated in prostate cancer that has metastasized to the bone. However, the regulatory mechanism of combinatorial Ras and WNT signaling in advanced prostate cancer is still unclear. TCF7, a WNT signaling-related gene, has been implicated as a critical factor in bone metastasis, and here we show that TCF7 is a direct target of miR-34a. In samples of prostate cancer patients, miR-34a levels are inversely correlated with TCF7 expression and a WNT dependent gene signature. Ectopic miR-34a expression inhibited bone metastasis and reduced cancer cell proliferation in a Ras-dependent xenograft model. We demonstrate that miR-34a can directly interfere with the gene expression of the anti-proliferative BIRC5, by targeting BIRC5 3′UTR. Importantly, BIRC5 overexpression was sufficient to reconstitute anti-apoptotic signaling in cells expressing high levels of miR-34a. In prostate cancer patients, we found that BIRC5 levels were positively correlated with a Ras signaling signature expression. Our data show that the bone metastasis and anti-apoptotic effects found in Ras signaling-activated prostate cancer cells require miR-34a deficiency, which in turn aids in cell survival by activating the WNT and anti-apoptotic signaling pathways thereby inducing TCF7 and BIRC5 expressions.     

Scavenger receptor class B type I regulates cellular cholesterol metabolism and cell signaling associated with breast cancer development

Introduction

Previous studies have identified cholesterol as an important regulator of breast cancer development. High-density lipoprotein (HDL) and its cellular receptor, the scavenger receptor class B type I (SR-BI) have both been implicated in the regulation of cellular cholesterol homeostasis, but their functions in cancer remain to be established.

Methods

In the present study, we have examined the role of HDL and SR-BI in the regulation of cellular signaling pathways in breast cancer cell lines and in the development of tumor in a mouse xenograft model.

Results

Our data show that HDL is capable of stimulating migration and can activate signal transduction pathways in the two human breast cancer cell lines, MDA-MB-231 and MCF7. Furthermore, we also show that knockdown of the HDL receptor, SR-BI, attenuates HDL-induced activation of the phosphatidylinositol 3-kinase (PI3K)/protein Kinase B (Akt) pathway in both cell lines. Additional investigations show that inhibition of the PI3K pathway, but not that of the mitogen-activated protein kinase (MAPK) pathway, could lead to a reduction in cellular proliferation in the absence of SR-BI. Importantly, whereas the knockdown of SR-BI led to decreased proliferation and migration in vitro, it also led to a significant reduction in tumor growth in vivo. Most important, we also show that pharmacological inhibition of SR-BI can attenuate signaling and lead to decreased cellular proliferation in vitro. Taken together, our data indicate that both cholesteryl ester entry via HDL-SR-BI and Akt signaling play an essential role in the regulation of cellular proliferation and migration, and, eventually, tumor growth.

Conclusions

These results identify SR-BI as a potential target for the treatment of breast cancer.     

Associations of C-X-C motif chemokine ligands 1/2/8/13/14 with clinicopathological features and survival profile in patients with colorectal cancer

The present study aimed to assess the correlation of C-X-C motif chemokine ligand (CXCL)1, CXCL2, CXCL8, CXCL13 and CXCL14 with clinicopathological features and survival profile in patients with colorectal cancer (CRC). Patients with primary CRC (n=232) were retrospectively reviewed, with their tumor tissue specimens acquired from the Department of Pathology (The First Hospital of Jilin University, Changchun, China), their demographic data and preoperative tumor features collected from the hospital database, and their survival data obtained from the follow-up documents. Tumor CXCL expression was detected by immunohistochemistry (IHC). Based on the total IHC score, the expression of CXCL1, CXCL2, CXCL8, CXCL13 and CXCL14 was categorized as low expression (IHC score ≤3) and high expression (IHC score >3). CXCL1 (51.3% high and 48.7% low), CXCL2 (59.9% high and 40.1% low), CXCL8 (44.4% high and 55.6% low), CXCL13 (40.9% high and 59.1% low) and CXCL14 (31.0% high and 69.0% low) were expressed in CRC tumor tissues, and their expression levels were correlated with each other, except between CXCL8 and CXCL14, and between CXCL13 and CXCL14. CXCL1 was associated with a larger tumor size, and an advanced T stage, N stage and Tumor-Node-Metastasis (TNM) stage. CXCL2 was associated with an advanced N stage and TNM stage, and CXCL8 was associated with a greater T stage and TNM stage. CXCL13 was associated with a greater T stage, N stage and TNM stage, while CXCL14 was not associated with any clinical characteristics. As for survival, CXCL1, CXCL2, CXCL8 and CXCL13, but not CXCL14, were associated with poor overall survival (OS) rate, and further multivariate Cox''s regression model analysis revealed that CXCL1 independently predicted unfavorable OS in patients with CRC. Overall, CXCL1, CXCL2, CXCL8 and CXCL13 have good potential as an indicator for tumor features and survival in patients with CRC.     

Crk-associated substrate lymphocyte type regulates transforming growth factor-beta signaling by inhibiting Smad6 and Smad7

Crk-associated substrate lymphocyte type (Cas-L) is a 105 kDa docking protein with diverse functional properties, including regulation of cell division, proliferation, migration and adhesion. Cas-L is also involved in beta1 integrin- or antigen receptor-mediated signaling in B and T cells. In the present study, we demonstrate that Cas-L potentiates transforming growth factor-beta (TGF-beta) signaling pathway by interacting with Smad6 and Smad7. Immunoprecipitation experiments reveal that single domain deletion of full-length Cas-L completely abolishes its docking function with Smad6 and Smad7, suggesting that the natural structure of Cas-L is necessary for its association with Smad6 and Smad7. On the other hand, both N-terminal and C-terminal deletion mutants of Smad6 and Smad7 still retain their docking ability to Cas-L, suggesting that Smad6 and Smad7 possess several binding motifs to Cas-L. Moreover, Cas-L interaction with Mad-homology (MH)2 domain, but not with MH1 domain of Smad6 or Smad7, ameliorates TGF-beta-induced signaling pathway. Finally, depletion of Cas-L by small-interfering RNA oligo attenuates TGF-beta-induced growth inhibition of Huh-7 cells, with a concomitant reduction in phosphorylation of Smad2 and Smad3. These results strongly suggest that Cas-L is a potential regulator of TGF-beta signaling pathway.     

EMMPRIN regulates tumor growth and metastasis by recruiting bone marrow-derived cells through paracrine signaling of SDF-1 and VEGF

EMMPRIN, a cell adhesion molecule highly expressed in a variety of tumors, is associated with poor prognosis in cancer patients. Mechanistically, EMMPRIN has been characterized to contribute to tumor development and progression by controlling the expression of MMPs and VEGF. In the present study, by using fluorescently labeled bone marrow-derived cells (BMDCs), we found that the down-regulation of EMMPRIN expression in cancer cells reduces tumor growth and metastasis, and is associated with the reduced recruitment of BMDCs. Further protein profiling studies suggest that EMMPRIN controls BMDC recruitment through regulating the secretion of soluble factors, notably, VEGF and SDF-1. We demonstrate that the expression and secretion of SDF-1 in tumor cells are regulated by EMMPRIN. This study reveals a novel mechanism by which EMMPRIN promotes tumor growth and metastasis by recruitment of BMDCs through controlling secretion and paracrine signaling of SDF-1 and VEGF.