Loss of hSef promotes metastasis through upregulation of EMT in prostate cancer

We have previously reported that the negative signaling regulator Similar Expression to FGF (hSef) is downregulated in prostate cancer and its loss is associated with clinical metastasis. Here, we explored the mechanistic basis of this finding. We first confirmed our clinical observation by testing hSef manipulation in an in vivo metastasis model. hSef stable expressing cells (PC3M‐hSef) or empty vector controls (PC3M‐EV) were injected subcutaneously into the lateral thoracic walls of NOD‐SCID gamma mice and lungs were harvested at autopsy. In this model, 6/7 PC3M‐EV xenografts had definitive lung micro‐metastasis whilst only 1/6 PC3M‐hSef xenografts exhibited metastasis recapitulating the clinical scenario (p = 0.03). Gene expression studies revealed key perturbations in genes involved in cell motility and epithelial to mesenchymal transition (EMT) along with alterations in cognate signaling pathways. These results were validated in an EMT specific PCR array whereby hSef over‐expression and silencing reciprocally altered E‐Cadherin expression (p = <0.001) amongst other EMT markers. Immunohistochemistry of excised tumors from the xenografts also confirmed the effect of hSef in suppressing E‐Cadherin expression at the protein level. Phosphokinase arrays further demonstrated a role for hSef in attenuating signaling of not only ERK‐MAPK but also the JNK and p38 pathways as well. Taken together, these data suggest evidence that loss of hSef may be a critical event facilitating tumor dissemination of prostate cancer through alteration of EMT. Detection of downregulated hSef, along with other negative regulators, may therefore be a useful biomarker heralding a transition to a metastatic phenotype and warrants further exploration in this context.     

ATP‐P2Y2‐β‐catenin axis promotes cell invasion in breast cancer cells

Extracellular adenosine 5′‐triphosphate (ATP), secreted by living cancer cells or released by necrotic tumor cells, plays an important role in tumor invasion and metastasis. Our previous study demonstrated that ATP treatment in vitro could promote invasion in human prostate cancer cells via P2Y2, a preferred receptor for ATP, by enhancing EMT process. However, the pro‐invasion mechanisms of ATP and P2Y2 are still poorly studied in breast cancer. In this study, we found that P2Y2 was highly expressed in breast cancer cells and associated with human breast cancer metastasis. ATP could promote the in vitro invasion of breast cancer cells and enhance the expression of β‐catenin as well as its downstream target genes CD44, c‐Myc and cyclin D1, while P2Y2 knockdown attenuated above ATP‐driven events in vitro and in vivo. Furthermore, iCRT14, a β‐catenin/TCF complex inhibitor, could also suppress ATP‐driven migration and invasion in vitro. These results suggest that ATP promoted breast cancer cell invasion via P2Y2‐β‐catenin axis. Thus blockade of the ATP‐P2Y2‐β‐catenin axis could suppress the invasive and metastatic potential of breast cancer cells and may serve as potential targets for therapeutic interventions of breast cancer.     

FBXO31 promotes cell proliferation,metastasis and invasion in lung cancer

FBXO31 is a member of F-box family which is involved in diverse biological functions and development of disease. Recent reports in breast cancer, hepatocellular carcinoma and ovarian cancer demonstrated inhibitory effect of FBXO31 on proliferation and tumorigenesis. However, the function of FBXO31 is not analyzed in lung cancer so far. In this study, we reported that expression of FBXO31 was higher in lung cancer tissues compared with non-cancerous lung tissues, and that higher expression of FBXO31 was significantly associated with tumor size, tumor infiltration, clinical stages and lymph node metastasis. In addition, exogenous expression of FBXO31 promoted cell growth, metastasis and invasion in A549 cells. Conversely, silencing FBXO31 by specific siRNA caused inhibitory effect on cell growth, metastasis and invasion. Moreover, tumorigenicity assays in nude mice showed FBXO31 promoted tumor growth in vivo. In conclusion, our data suggest FBXO31 promotes cell proliferation, metastasis and invasion in lung cancer.     

The reversible P2Y12 inhibitor ticagrelor inhibits metastasis and improves survival in mouse models of cancer

Tumor cells use activated platelets to promote their proliferation and metastatic potential. Because platelet activation is largely mediated through ADP engagement of purinergic P2Y12 receptors on platelets, we investigated the potential of the reversible P2Y12 inhibitor ticagrelor, a clinical agent used in the prevention of cardiovascular and cerebrovascular events, to inhibit tumor adhesion and metastasis. In B16‐F10 melanoma intravenous and intrasplenic metastasis models, mice treated with a clinical dose of ticagrelor (10 mg/kg) exhibited marked reductions in lung (84%) and liver (86%) metastases. Furthermore, ticagrelor treatment improved survival compared to saline‐treated animals. A similar effect was observed in a 4T1 breast cancer model, with reductions in lung (55%) and bone marrow (87%) metastases following ticagrelor treatment. In vitro, B16‐F10 cells exhibited decreased interaction with platelets from ticagrelor‐treated mice compared to saline‐treated mice, an effect similar to that observed with blockade of glycoprotein IIbIIIa. Similarly, B16‐F10 cells co‐incubated with platelets from ticagrelor‐treated mice exhibited reduced adhesion to endothelial monolayers compared to those co‐incubated with platelets from saline‐treated animals, an effect also observed in vivo. Interestingly, pretreatment of endothelial monolayers with ticagrelor did not result in reduced tumor cell adhesion. These findings support a role for P2Y12‐mediated platelet activation in promoting metastases, and provide proof‐of‐concept for the clinical use of ticagrelor in the prevention of tumor metastasis.     

RASAL2 down-regulation in ovarian cancer promotes epithelial-mesenchymal transition and metastasis

Ovarian cancer is the most lethal gynecologic malignancy, and transcoelomic metastasis is responsible for the greatest disease mortality. Although intensive efforts have been made, the mechanism behind this process remains unclear. RASAL2 is a GTPase activating proteins (GAPs) which was recently reported as a tumor suppressor in breast cancer. In this study, we identified RASAL2 as a regulator of epithelial-mesenchymal transition (EMT) and metastasis in ovarian cancer. RASAL2 was down-regulated in ovarian cancer samples compared with normal tissue samples, especially in advanced stages and grades. RASAL2 knockdown in ovarian cancer cell lines promoted in vitro anchorage-independent growth, cell migration and invasion and in vivo tumor formation. Moreover, we observed EMT in RASAL2-depleted cells. E-cadherin-mediated cell-cell adhesion was attenuated, and mesenchymal markers were up-regulated. Further investigation revealed that the oncogenic role of RASAL2 down-regulation was mediated by the Ras-ERK pathway. RASAL2 knockdown activated the Ras-ERK pathway, and inhibition of the pathway reversed the functional effects of RASAL2 depletion. Together, our results implicate RASAL2 as an EMT regulator and tumor suppressor in ovarian cancer, and down-regulation of RASAL2 promotes ovarian cancer progression.     

miRNA与肿瘤侵袭转移

目前,microRNA (miRNA)已成为肿瘤研究中最基本的参与者,主要通过与靶标基因3 'UTR(非翻译区)的完全或不完全配对,降解靶标基因mRNA或抑制其翻译,从而参与调控个体发育、细胞凋亡、增殖及分化等生命活动.miRNA作为调控基因表达的重要分子在肿瘤侵袭转移中的作用越来越受到重视,表明miRNA在肿瘤侵袭和转移中的作用机制具有重要的理论意义,同时也可为肿瘤的诊断和治疗提供新方法.本文就miRNA通过调控上皮间质转化及肿瘤干细胞导致肿瘤侵袭转移的最新研究进展作一综述.     

SRC激酶抑制剂对前列腺癌细胞侵袭与增殖的影响

目的：以PP2[4-Amino-5-（4-Chloro-Phenyl）-7-（t-Butyl）Pyrazolo（3,4-d）Pyrimidine]药物（src激酶抑制剂）处理前列腺癌细胞,检测src激酶及E-cadherin蛋白表达水平的变化,探讨PP2对前列腺癌细胞增殖和侵袭能力的影响。方法：PP2处理前列腺癌细胞PC-3,Western blot检测src及其相关蛋白的表达;Boyden小室实验检测细胞侵袭能力;MTT检测细胞的增殖能力。结果：PP2处理PC-3细胞后,src表达水平明显降低,E-cadherin表达水平升高;细胞的增殖和侵袭能力均受到明显抑制,剂量越高抑制作用越明显（P〈0.05）。结论：PP2通过提高细胞黏附分子E-cadherin的表达抑制前列腺癌细胞PC-3的增殖和侵袭能力。     

SRC激酶抑制剂对前列腺癌细胞侵袭与增殖的影响

目的:以PP2[4-Amino-5-(4-Chloro-Phenyl)-7-(t-Butyl)Pyrazolo(3,4-d)Pyrimidine]药物(src激酶抑制剂)处理前列腺癌细胞,检测src激酶及E-cadherin蛋白表达水平的变化,探讨PP2对前列腺癌细胞增殖和侵袭能力的影响。方法:PP2处理前列腺癌细胞PC-3,Western blot检测src及其相关蛋白的表达;Boyden小室实验检测细胞侵袭能力;MTT检测细胞的增殖能力。结果:PP2处理PC-3细胞后,src表达水平明显降低,E-cadherin表达水平升高;细胞的增殖和侵袭能力均受到明显抑制,剂量越高抑制作用越明显(P<0.05)。结论:PP2通过提高细胞黏附分子E-cadherin的表达抑制前列腺癌细胞PC-3的增殖和侵袭能力。     

ARHGEF40通过上皮间质转化促进结肠癌细胞侵袭

目的:研究鸟嘌呤核苷酸交换因子40(recombinant human rho guanine nucleotide exchange factor 40,ARHGEF40)对结肠癌细胞侵袭能力和上皮间质转化(epithelial-mesenchymal transition,EMT)标志蛋白表达的影响,探索ARHGE...     

Estrogen and estrogen receptor alpha promotes malignancy and osteoblastic tumorigenesis in prostate cancer

The role of estrogen signaling in regulating prostate tumorigenesis is relatively underexplored. Although, an increasing body of evidence has linked estrogen receptor beta (ERβ) to prostate cancer, the function of estrogen receptor alpha (ERα) in prostate cancer is not very well studied. We have discovered a novel role of ERα in the pathogenesis of prostate tumors. Here, we show that prostate cancer cells express ERα and estrogen induces oncogenic properties in prostate cancer cells through ERα. Importantly, ERα knockdown in the human prostate cancer PacMetUT1 cells as well as pharmacological inhibition of ERα with ICI 182,780 inhibited osteoblastic lesion formation and lung metastasis in vivo. Co-culture of pre-osteoblasts with cancer cells showed a significant induction of osteogenic markers in the pre-osteoblasts, which was attenuated by knockdown of ERα in cancer cells suggesting that estrogen/ERα signaling promotes crosstalk between cancer and osteoblastic progenitors to stimulate osteoblastic tumorigenesis. These results suggest that ERα expression in prostate cancer cells is essential for osteoblastic lesion formation and lung metastasis. Thus, inhibition of ERα signaling in prostate cancer cells may be a novel therapeutic strategy to inhibit the osteoblastic lesion development as well as lung metastasis in patients with advanced prostate cancer.     

Suppression of death receptor 5 enhances cancer cell invasion and metastasis through activation of caspase-8/TRAF2-mediated signaling

The role of death receptor 5 (DR5), a well-known cell surface pro-apoptotic protein, in the negative regulation of invasion and metastasis of human cancer cells and the underlying mechanisms are largely unknown and were hence the focus of this study. In this report, we have demonstrated that DR5 functions to suppress invasion and metastasis of human cancer cells, as evidenced by enhanced cancer cell invasion and metastasis upon genetic suppression of DR5 either by gene knockdown or knockout. When DR5 is suppressed, FADD and caspase-8 may recruit and stabilize TRAF2 to form a metastasis and invasion signaling complex, resulting in activation of ERK and JNK/AP-1 signaling that mediate the elevation and activation of matrix metalloproteinase-1 (MMP1) and eventual promotion of cancer invasion and metastasis. Our findings thus highlight a novel non-apoptotic function of DR5 as a suppressor of human cancer cell invasion and metastasis and suggest a basic working model elucidating the underlying biology.     

Acid ceramidase-mediated production of sphingosine 1-phosphate promotes prostate cancer invasion through upregulation of cathepsin B

Invasiveness is one of the key features of aggressive prostate cancer; however, our understanding of the precise mechanisms effecting invasion remains limited. The ceramide hydrolyzing enzyme acid ceramidase (AC), overexpressed in most prostate tumors, causes an aggressive and invasive phenotype through downstream effectors that have not yet been well characterized. Here, we demonstrate that AC, through generation of sphingosine-1-phosphate (S1P), promotes Ets1 nuclear expression and binding to the promoter region of matrix-degrading protease cathepsin B. Through confocal microscopy and flow cytometry, we found that AC overexpression promotes pericellular localization of cathepsin B and its translocation to the outer leaflet of the cell membrane. AC overexpressing cells have an increased abundance of cathepsin B-enriched invasive structures and enhanced ability to invade through a collagen matrix, but not in the presence of an inhibitor of cathepsin B. In human prostate tissues, AC and cathepsin B overexpression were strongly associated and may relate to poor outcome. These results demonstrate a novel pathway by which AC, through S1P, promotes an invasive phenotype in prostate cancer by causing overexpression and secretion of cathepsin B through activation and nuclear expression of Ets1. As prostate cancer prognosis is dramatically worse when invasion has occurred, this study provides critical insight into the progression toward lethal prostate cancer.     

Exogenous fatty acid binding protein 4 promotes human prostate cancer cell progression

Epidemiologic studies have found that obesity is associated with malignant grade and mortality in prostate cancer. Several adipokines have been implicated as putative mediating factors between obesity and prostate cancer. Fatty acid binding protein 4 (FABP4), a member of the cytoplasmic fatty acid binding protein multigene family, was recently identified as a novel adipokine. Although FABP4 is released from adipocytes and mean circulating concentrations of FABP4 are linked with obesity, effects of exogenous FABP4 on prostate cancer progression are unclear. In this study, we examined the effects of exogenous FABP4 on human prostate cancer cell progression. FABP4 treatment promoted serum‐induced prostate cancer cell invasion in vitro. Furthermore, oleic acid promoted prostate cancer cell invasion only if FABP4 was present in the medium. These promoting effects were reduced by FABP4 inhibitor, which inhibits FABP4 binding to fatty acids. Immunostaining for FABP4 showed that exogenous FABP4 was taken up into DU145 cells in three‐dimensional culture. In mice, treatment with FABP4 inhibitor reduced the subcutaneous growth and lung metastasis of prostate cancer cells. Immunohistochemical analysis showed that the number of apoptotic cells, positive for cleaved caspase‐3 and cleaved PARP, was increased in subcutaneous tumors of FABP4 inhibitor‐treated mice, as compared with control mice. These results suggest that exogenous FABP4 might promote human prostate cancer cell progression by binding with fatty acids. Additionally, exogenous FABP4 activated the PI3K/Akt pathway, independently of binding to fatty acids. Thus, FABP4 might be a key molecule to understand the mechanisms underlying the obesity‐prostate cancer progression link.     

TOP2Ahigh is the phenotype of recurrence and metastasis whereas TOP2Aneg cells represent cancer stem cells in prostate cancer

Recurrence and metastasis are the main causes of death for prostate cancer patients and cancer stem cells (CSCs) are proposed to play important roles in cancer recurrence and metastasis. It is generally thought that genes upregulated in recurrent/metastatic disease are likely biomarkers of CSCs. Hence we analyzed multiple microarray datasets on prostate tumor tissues to identify upregulated genes associated with cancer recurrence/metastasis, and tried to explore whether those genes were true biomarkers of prostate CSCs. Our results indicated that TOP2A was the most highly upregulated gene in recurrent/metastatic prostate cancer, and its high expression was positively correlated with poor prognosis in patients. Using a promoter reporter system, we unexpectedly discovered enrichment of CSCs in TOP2A^neg cells. Compared to TOP2A^high cells, TOP2A^neg cells formed spheres and tumors more efficiently, and became enriched in the presence of stresses. Analysis of cell divisions by time lapse imaging indicated that more slow-cycling cells were observed in TOP2A^neg cells while the proportion of abnormal divisions was higher in TOP2A^high cells. Our studies demonstrate that TOP2A^high is the phenotype of recurrence/metastasis but TOP2A^neg cells show slow cycling and have CSCs properties in prostate cancer, which has significant implications for prostate cancer therapy.     

干扰CIP2A表达对前列腺癌细胞增殖、凋亡和侵袭的影响

目的 探讨干扰蛋白磷酸酶2A癌性抑制因子(CIP2A)表达对前列腺癌细胞增殖、凋亡和侵袭的影响.方法 应用siRNA干扰前列腺癌DU-145细胞的CIP2A表达后,检测细胞的增殖及凋亡水平.采用实时定量PCR和蛋白质印迹法检测CIP2A的表达水平;采用MTT实验检测细胞增殖水平;采用流式细胞术检测细胞周期和凋亡水平;采用TranswellTM实验检测细胞侵袭水平.结果 siRNA干扰前列腺癌DU-145细胞的CIP2A表达,干扰效率为80%.培养120 h后,CIP2A siRNA组前列腺癌DU-145细胞的增殖率为(94.02±4.21)%,低于对照组的(135.21±4.13)%(P﹤0.05).CIP2A siRNA组G1期细胞所占比例为(58.07±2.10)%,高于对照组的(50.73±2.30)%(P﹤0.05).CIP2A siRNA组前列腺癌DU-145细胞的穿膜细胞数为(93.00±4.80)个,少于对照组的(143.00±15.80)个(P﹤0.05).结论 CIP2A在前列腺癌细胞的增殖、凋亡和侵袭中起着及其重要的作用,并有可能成为前列腺癌的治疗新靶点.     

环加氧酶-2 通过调控EMT促进乳腺癌MDA-MB-231 细胞的迁移和侵袭

[摘要] 目的：探讨环加氧酶-2（COX-2）在乳腺癌转移中的作用及其可能的机制。方法：收集从2015 年10 月至2018 年4 月在云南省肿瘤医院接受乳腺切除术的患者中获得的原发乳腺癌组织和脑转移乳腺癌组织临床病理样本共45 例,其中原发30 例、脑转移15 例。采用qPCR检测COX-2 在原位乳腺癌和脑转移乳腺癌组织中的表达。将COX-2 过表达重组病毒（LV6-COX2）或敲减COX-2 重组病毒（LV3-COX2 shRNA1、LV3-COX2 shRNA2）感染人乳腺癌MDA-MB-231 细胞并获得稳转细胞株后,CCK-8法检测COX-2 表达对MDA-MB-231 细胞增殖的影响,划痕实验和Transwell 法检测对MDA-MB-231 细胞迁移和侵袭的影响。qPCR和WB实验分析各组细胞中COX-2 mRNA和蛋白的表达水平,qPCR检测COX-2 表达对MDA-MB-231 细胞内EMT相关基因表达的影响。结果：COX-2 表达水平在脑转移乳腺癌患者组织中显著高于原位乳腺癌组织（P<0.01）;并且与乳腺癌患者肿瘤TMN分期有关。成功构建稳定过表达/敲减COX-2 的MDA-MB-231 细胞株。过表达COX-2 促进MDA-MB-231 细胞的迁移和侵袭（均P<0.01）,同时显著提高MMP2、MMP1、N-cadherin 和vimentin 的表达（均P<0.01）,但对细胞增殖无明显影响;而沉默COX-2 则有相反的作用,且可促进细胞增殖（P<0.05）。结论：COX-2 在脑转移乳腺癌组织中高表达,其可能通过调控EMT过程促进乳腺癌MDA-MB-231 细胞的迁移和侵袭。