A selective small molecule inhibitor of c-Met, PHA665752, inhibits tumorigenicity and angiogenesis in mouse lung cancer xenografts

The c-Met receptor tyrosine kinase is emerging as a novel target in many solid tumors, including lung cancer. PHA-665752 was identified as a small molecule, ATP competitive inhibitor of the catalytic activity of the c-Met kinase. Here, we show that treatment with PHA665752 reduced NCI-H69 (small cell lung cancer) and NCI-H441 (non-small cell lung cancer) tumorigenicity in mouse xenografts by 99% and 75%, respectively. Reduction in tumor size was also observed by magnetic resonance imaging of tumors in mice. PHA665752 inhibited c-Met phosphorylation at the autophosphorylation and c-Cbl binding sites in mouse xenografts derived from non-small cell lung cancer cell lines (NCI-H441 and A549) and small cell lung cancer cell line (NCI-H69). PHA665752 also inhibited angiogenesis by >85% in all the abovementioned cell lines and caused an angiogenic switch which resulted in a decreased production of vascular endothelial growth factor and an increase in the production of the angiogenesis inhibitor thrombospondin-1. These studies show the feasibility of selectively targeting c-Met with ATP competitive small molecule inhibitors and suggest that PHA665752 may provide a novel therapeutic approach to lung cancer.     

PQ401, an IGF-1R inhibitor,induces apoptosis and inhibits growth,proliferation and migration of glioma cells

Growth factor signalling pathways transduce extra-cellular physiological cues to guide cells to maintain critical cellular functions, including cell proliferation, survival and metabolism. Dysregulation of certain growth factor signalling pathways has been shown as a major route to promote tumourigenesis. Glioma is a type of aggressive malignant tumour with no effective systematic therapy so far. Overexpression or hyperactivation of IGF-1R has been observed to be tightly associated with glioma progression and poor prognosis. Here, we examined the biological effects of a specific IGF-1R inhibitor, PQ401, on suppressing U87MG glioma cell growth and migration. Specifically, we observed that PQ401 not only induced cellular apoptosis in U87MG cells and subsequently reduced cell viability and proliferation but also attenuated cell mobility in vitro. More importantly, through a mouse xenograft model, we observed that administration of PQ401 on mice led to suppression of glioma tumour growth in vivo. In summary, our study suggests that PQ401 may serve as a promising leading drug for treating glioma patients with elevated IGF-1R signalling.     

腺苷抑制乳腺癌细胞增殖和迁移的机制

目的:检测腺苷对乳腺肿瘤细胞增殖及迁移能力的影响,并探究其潜在的分子机制。方法:以MCF-7细胞为模型,采用梯度浓度的腺苷处理细胞,MTT及细胞计数法检测腺苷对细胞增殖的影响,流式细胞术检测腺苷对细胞凋亡及周期的影响,划痕修复实验检测腺苷对细胞迁移能力的影响。结果:腺苷可显著抑制MCF-7细胞增殖,且抑制效果与腺苷浓度及作用时间呈相关性。流式细胞术检测结果表明腺苷可诱导MCF-7细胞凋亡,并引起细胞的 G2/M期阻滞。划痕实验结果表明腺苷抑制MCF-7细胞的迁移能力。实时定量PCR检测结果发现,促细胞凋亡分子Bax及Bak表达量显著升高,而凋亡抑制分子Bcl-2表达量显著下降,同时Caspase-3的表达量也显著升高。结论:腺苷可诱导MCF-7细胞凋亡,抑制细胞的增殖,同时腺苷可以抑制MCF-7细胞的迁移能力。腺苷诱导MCF-7细胞凋亡与其激活线粒体凋亡通路密切相关。     

Transforming growth factor beta2 inhibition of hepatocyte growth factor-induced endothelial proliferation and migration

Angiogenesis is a highly controlled event which depends on the proper equilibrium of activators and inhibitors present within the microenvironment. Hepatocyte Growth Factor (HGF) activates migration and proliferation of endothelial cells and is angiogenic, acting through the tyrosine kinase receptor encoded by the Met protooncogene. To get insights into the molecular mechanisms involved in HGF-induced angiogenesis, we searched for cDNAs differentially expressed in human endothelial cells exposed to HGF, a potent angiogenic factor. We found that HGF-treated endothelial cells upregulated the expression of Transforming Growth Factor (TGF) beta2. To understand the significance of this finding, we cultured endothelial cells with HGF and TGF beta2 simultaneously. We found that TGF beta2 impairs HGF-dependent proliferative and migratory responses. TGF beta2 did not prevent the tyrosine phosphorylation of Met, but it inhibited some signalling pathways activated by HGF. We show that endothelial proliferation induced by HGF required the activation of the MAPK cascade, while HGF-induced endothelial migration was dependent on the tyrosine phosphorylation of Src. Indeed, TGF beta2 inhibited HGF effects because it prevented HGF-induced MAP kinase activation and tyrosine phosphorylation of Src. We suggest that the induction of TGF beta2 by HGF in endothelial cells may represent a physiologic mechanism to counterbalance HGF angiogenic activity.     

microRNA-122抑制胰腺癌细胞增殖、迁移和侵袭

目的 明确microRNA-122(miR-122)在胰腺癌中的表达及miR-122对胰腺癌细胞增殖、迁移和侵袭的作用.方法 采用RT-qPCR方法检测20例胰腺癌组织、胰腺癌细胞株(ASPC1、PANC1、MP和SW1990)和人源正常胰腺导管上皮细胞株(HPDE)中miR-122的表达量.将miR-122模拟类似物...     

Prostaglandin D2 inhibits the proliferation of human neuroblastoma cells

The cytotoxic action of prostaglandin (PG) D₂, E₁ and F_2α was examined on human neuroblastoma cells (NB-1 cell line), and PGD₂ was found to be the most effective. PGE₁, thought to be the most effective among all PG_s in the therapy of neuroblastoma, was much less effective than PGD₂. PGF_2α did not show any inhibitory effect on the proliferation of NB-1 cells. When PGD₂ was added, the cytoplasma became microscopically larger, then the cells gradually died off. PGD₂ also exerted a dose-dependent inhibition of DNA and RNA syntheses. These results strongly suggest an antineoplastic activity of PGD₂ for human neuroblastoma.     

吴茱萸碱对神经母细胞瘤SK-N-SH细胞增殖、迁移及侵袭的影响

目的：探讨吴茱萸碱（Evo）是否通过调控lncRNA LINC00858 表达调控神经母细胞瘤SK-N-SH 细胞的增殖、迁移及侵袭。方法：在体外以3、6、12 μmol/L Evo 处理人神经母细胞瘤SK-N-SH 细胞,利用RNA干扰技术分别将si-NC、si-LINC00858转染至SK-N-SH 细胞,将pcDNA、pcDNA-LINC00858 转染至SK-N-SH 细胞并经12 μmol/L Evo 处理,实验分为对照组、Evo 低剂量组、Evo 中剂量组、Evo 高剂量组、si-NC 组、si-LINC00858 组、Evo+pcDNA 组、Evo+pcDNA-LINC00858 组。采用qPCR法检测各组细胞LINC00858 的表达量,MTT、Transwell 实验分别检测细胞的增殖、迁移、侵袭能力,WB 法检测细胞中cyclinD1、MMP-2、 MMP-9和p21 蛋白的表达。结果：与对照组相比,Evo低、中、高剂量组SK-N-SH 细胞中LINC00858 表达均显著降低（均P<0.05）,细胞增殖抑制率显著升高、迁移及侵袭细胞数显著减少（均P<0.01）,cyclinD1、MMP-2、MMP-9 蛋白表达降低、p21 蛋白表达升高（均P<0.01）。与si-NC 组相比,si-LINC00858 组细胞的增殖抑制率、迁移和侵袭细胞数及相关蛋白表达变化同Evo 低、中、高剂量组。与Evo+pcDNA 组相比,Evo+pcDNA-LINC00858 组细胞的增殖抑制率显著降低、迁移及侵袭细胞数均显著增多（均P<0.01）,cyclinD1、MMP-2、MMP-9蛋白表达升高、p21蛋白表达降低（均P<0.05）。结论：Evo 通过下调LINC00858 表达抑制神经母细胞瘤SK-N-SH细胞的增殖、迁移及侵袭。     

Co-expression of hepatocyte growth factor and c-Met predicts peritoneal dissemination established by autocrine hepatocyte growth factor/c-Met signaling in gastric cancer

Epithelial-mesenchymal transition (EMT) promotes and facilitates migration and invasion of epithelial tumor cells. EMT is induced by factors such as hepatocyte growth factor (HGF). This study aimed to establish whether the HGF/c-Met pathway is associated with gastric cancer metastasis; especially peritoneal dissemination. HGF and c-Met expression and EMT-related molecules were evaluated using real-time PCR and immunohistochemistry. The role of the HGF/c-Met pathway in EMT and anoikis was determined, and kinase inhibitor SU11274 was tested for its ability to block HGF-induced biological effects. In HGF(-) /c-Met(+) gastric cancer cells, recombinant HGF promoted an EMT phenotype that was characterized by morphology, impaired E-cadherin and induction of vimentin. HGF promoted cell growth, invasiveness and migration and inhibition of anoikis. SU11274 blocked HGF-induced EMT and biological effects in vitro. In HGF(+) /c-Met(+) gastric cancer cells, HGF did not affect the biological outcome of EMT and anoikis, but SU11274 exerted the same inhibitory effects as in HGF(-) /c-Met(+) cells. In vivo, HGF(+) /c-Met(+) gastric cancer cells only established peritoneal dissemination and SU11274 inhibited tumor growth. Clinically, HGF expression was significantly correlated with c-Met expression in gastric cancer. Increased HGF and c-Met had a significant association with poor prognosis and predicted peritoneal dissemination. We demonstrated that the HGF/c-Met pathway induces EMT and inhibition of anoikis in gastric cancer cells. Co-expression of HGF and c-Met has the potential to promote peritoneal dissemination in gastric cancer. Blockade of the autocrine HGF/c-Met pathway could be clinically useful for the treatment of peritoneal dissemination in gastric cancer.     

Silencing of c-Met by RNA interference inhibits the survival,proliferation, and invasion of nasopharyngeal carcinoma cells

c-Met is a tyrosine kinase receptor that mediates pleiotropic cellular responses following its activation by hepatocyte growth factor. The overexpression of c-Met in nasopharyngeal carcinoma (NPC) has been described recently, but the functional role of c-Met in NPC remains incompletely understood. This study aimed to investigate the potential mechanism by which c-Met contributes to the tumorigenesis of NPC. In the present study, by using RNA interference we silenced the expression of c-Met in CNE-2 cells, a poorly differentiated NPC cell line. Our in vitro studies showed that shRNA-mediated depletion of c-Met resulted in the suppression of proliferation, migration, and invasion, as well as an increase in the apoptosis of CNE-2 cells. Moreover, in xenograft nude mice we demonstrated that the depletion of c-Met resulted in reduced tumor growth and increased apoptosis in xenografts. Taken together, these results suggest that c-Met plays an oncogenic role in the development of NPC and reveal it as a potential novel therapeutic target for NPC.     

Demethoxycurcumin inhibits cell proliferation, migration and invasion in prostate cancer cells

Curcumin (CUR) is a natural agent that has been demonstrated to effectively inhibit prostate cancer growth. However, natural CUR is relatively unstable and can be easily degraded in vivo. Therefore, it is essential to develop other stable curcuminoids. Demethoxycurcumin (DMC) is a candidate that has been verified in several tumor types and has potential for the treatment of prostate cancer. In the present study, we investigated the effects of DMC on proliferation, apoptosis and migration of PC-3 cells. MTT assay results indicated that DMC inhibited PC-3 cell viability in a dose- and time-dependent manner, and DMC induced G2/M phase arrest. Furthermore, PC-3 cells in DMC-treated groups had a higher apoptotic rate compared with DMSO-treated control. This effect may be due to the activation of the caspase-3 pathway. In DMC-treated groups, migrating and invasive cells were dramatically reduced (P<0.05). The activity of MMP-2, which is correlated with migration and invasion was also suppressed by DMC. These results indicated that DMC may inhibit PC-3 cell migration and invasion partially by affecting MMP-2 activity. In conclusion, DMC significantly inhibits proliferation, migration and invasion of cultured PC-3 cells, and this study may provide evidence for future in vivo studies and clinical use.     

miR-34a inhibits migration and invasion by down-regulation of c-Met expression in human hepatocellular carcinoma cells

Several studies have shown that miR-34a represses the expression of many genes and induces G1 arrest, apoptosis, and senescence. In the present study, we identified the role of miR-34a in the regulation of tumor cell scattering, migration, and invasion. Down-regulation of miR-34a expression was highly significant in 19 of 25 (76%) human hepatocellular carcinoma (HCC) tissues compared with adjacent normal tissues and associated with the metastasis and invasion of tumors. Furthermore, resected normal/tumor tissues of 25 HCC patients demonstrated an inverse correlation between miR-34a and c-Met-protein. In HepG2 cells, ectopic expression of miR-34a potently inhibited tumor cell migration and invasion in a c-Met-dependent manner. miR-34a directly targeted c-Met and reduced both mRNA and protein levels of c-Met; thus, decreased c-Met-induced phosphorylation of extracellular signal-regulated kinases 1 and 2 (ERK1/2). Taken together, these results provide evidence to show the suppression role of miR-34a in tumor migration and invasion through modulation of the c-Met signaling pathway.     

microRNA-449抑制脉络膜黑色素瘤细胞的增殖和迁移

目的探讨脉络膜黑色素瘤细胞M21转染microRNA-449后对增殖和迁移的影响,及其分子机制的初探。方法采用阳离子脂质体Lipofectamine介导的方法,将microRNA-449转染入体外培养的人脉络膜黑色素瘤细胞。应用MTS法检测转染后细胞增殖的影响;Transwell小室检测细胞迁移的变化;Western blotting检测c-Met蛋白的表达。结果转染microRNA-449后,脉络膜黑色素瘤细胞增殖明显被抑制（P〈0.01）,迁移亦受抑制（P〈0.01）,c-Met表达量下降。结论转染microRNA-449对体外培养的人脉络膜黑色素瘤细胞的增殖和迁移具有抑制作用,microRNA-449可下调c-Met蛋白的表达水平。     

The HSP90 inhibitor 17-PAG effectively inhibits the proliferation and migration of androgen-independent prostate cancer cells

Castration-resistant prostate cancer (CRPC) ultimately occurs after a period of treatment with androgen deprivation therapy. Furthermore, CRPC patients can only derive limited survival benefits from traditional cytotoxic drugs. HSP90, which is a molecular chaperone, plays a vital role in client protein processing and maintaining the function of cells. HSP90 is usually overexpressed in prostate cancer tissues, which makes it a potential target for managing prostate cancer. Geldanamycin (GA), which was recognized as the first natural HSP90 inhibitor, has demonstrated potent anti-tumor efficacy in large-scale pre-clinical studies, but its application in the clinic is not permitted due to its liver toxicity and unstable physical properties. In this study, we report a new GA derivative, 17-PAG (17-(propynylamino)-17-demethoxygeldanamycin), which demonstrates highly effective anti-tumor activity against androgen-independent prostate cancer cells. Treating cells with 17-PAG dose-dependently suppressed proliferation, reduced colony formation and induced apoptosis of DU-145/C4-2B cells. Moreover, 17-PAG suppressed the migration and invasion of DU-145/C4-2B cells by regulating epithelial mesenchymal transition (EMT). 17-PAG also downregulated the HSP90 client proteins, including Her2, EGFR, C-Raf, AKT, p-AKT, and CDK4. Animal assays confirmed that 17-PAG shows strong anti-tumor effects with no obvious organ toxicity in DU-145 cell xenografted nude mice. These results provide us with a potential target for treating androgen-independent prostate cancer in a safe and effective manner.     

Down-regulation of c-Met and Bcl2 by microRNA-206, activates apoptosis,and inhibits tumor cell proliferation,migration and colony formation

Hsa-miRNA-206 (miR-206), highly expressed in skeletal muscle, has recently been discovered to have anticancer properties in different tissues. However, the role of miR-206 on lung cancer is still ambiguous. In this study, we investigated the role of miR-206 on the development of lung cancer. The results indicated that miR-206 expression was suppressed in lung cancer tissues and very low levels were found in non-small cell lung cancer (NSCLS) cell liness. Transient transfection of miR-206 into cultured A549 and SK-MES-1 cells led to significant decrease in cell growth, migration, invasion and colony formation, and promoted cell apoptosis. Using bioinformatics, we identified putative miR-206 binding sites within the 3′-untranslated region (3′-UTR) of the human c-Met and Bcl2 mRNA. The expression of c-Met and Bcl2 proteins were shown to be down-regulated after treated with miR-206 by subsequent Western blot and qRT-PCR analysis. Conversely, up-regulation of c-Met and Bcl2 were confirmed in tissue samples of human lung cancer, with its level inversely correlated with miR-206 expression. In addition, miR-206 also decreased the gene expression of MMP-9, CCND1 and CCND2 while increased the gene expression of p57 (Kip2) in A549 and SK-MES-1 cells. Taken together, our results demonstrated that miR-206 suppressed c-Met and Bcl2 expression in NSCLS and could function as a potent tumor suppressor in c-Met/Bcl2-over expressing tumors. Inhibition of miR-206 function could contribute to aberrant cell proliferation, migration, invasion and apoptosis, leading to NSCLS development.     

Epac inhibits migration and proliferation of human prostate carcinoma cells

Background:

It was recently found that cAMP mediates protein kinase A-independent effects through Epac proteins. The aim of this study was to investigate the role of Epac in migration and proliferation of prostate carcinoma cells.

Methods:

The effect of Epac activation was determined by [³H]thymidine incorporation and scratch assays in PC-3 and DU 145 cells. Furthermore, cytoskeletal integrity was analysed by phalloidin staining. The participation of intracellular Epac effectors such as mitogen-activated protein (MAP) kinases, Rap1- and Rho-GTPases was determined by immunoblotting and pull-down assay.

Results:

The specific Epac activator 8-pCPT-2′-O-Me-cAMP (8-pCPT) interfered with cytoskeletal integrity, reduced DNA synthesis, and migration. Although 8-pCPT activated Rap1, it inhibited MAP kinase signalling and RhoA activation. These findings were translated into functional effects such as inhibition of mitogenesis, cytoskeletal integrity, and migration.

Conclusion:

In human prostate carcinoma cells, Epac inhibits proliferative and migratory responses likely because of inhibition of MAP kinase and RhoA signalling pathways. Therefore, Epac might represent an attractive therapeutic target in the treatment of prostate cancer.     

Anesthetic pentobarbital inhibits proliferation and migration of malignant glioma cells

Malignant gliomas are common and aggressive brain tumors in adults. The rapid proliferation and diffuse brain migration are main obstacles to successful treatment. Here we show that pentobarbital, a central depressant introduced clinically a century ago, is capable of suppressing proliferation and migration of C6 malignant glioma cells in a concentration-dependent manner. Pentobarbital also leads to a G1 phase cell cycle arrest accompanied by suppressed G1 cell cycle regulatory proteins Cyclin D1, Cyclin D3, CDK2 and phosphorylated Rb. In addition, noticeable morphological changes and interrupted α-tubulin microtubule assembly are induced by pentobarbital exposure. Intracellular signal pathways involved in the effect of pentobarbital is concerned with inactivation of ERK, c-Jun and Akt. Together, these findings suggest anti-proliferation and anti-migration effects of pentobarbital on malignant gliomas, most likely by arresting cell cycle and interfering microtubule. ERK, c-Jun MAPK and PI3K/Akt are possible signaling pathways involved.     

KRC-408, a novel c-Met inhibitor,suppresses cell proliferation and angiogenesis of gastric cancer

Among many cancer therapeutic targets, c-Met receptor tyrosine kinase has recently given particular attention. This kinase and its ligand, hepatocyte growth factor (HGF), play a central role in cell proliferation and the survival of several human cancers. Thus, we developed KRC-408 as a novel c-Met inhibitor and investigated its anti-cancer effects on human gastric cancer. KRC-408 inhibited the phosphorylation of c-Met and its constitutive downstream effectors such as phosphatidylinositol 3-kinase (PI3K), Akt, Mek, and Erk. This compound was found to exert anti-cancer effects stronger than those of 5-fluorouracil (5-FU) on gastric cancer cells, especially cell lines that overexpressed c-Met. Interestingly, cytotoxicity of KRC-408 was lower than that of 5-FU in normal gastric cells. Apoptosis induced by KRC-408 was accompanied by increased levels of cleaved caspase-3 and PARP as well as DNA condensation and fragmentation. Flow cytometry analysis showed an accumulation of gastric cancer cells in the G2/M phase with concomitant loss of cells in the S phase following treatment with this drug. In the angiogenesis studies, KRC-408 inhibited tube formation and migration of human umbilical vein endothelial cells (HUVECs), and suppressed microvessel sprouting from rat aortic rings ex vivo along with blood vessel formation in a Matrigel plug assay in mice. Results of an in vivo mouse xenograft experiment showed that the administration of KRC-408 significantly delayed tumor growth in a dose-dependent manner, and suppressed Akt and Erk phosphorylation as well CD34 expression in tumor tissues. These findings indicate that KCR-408 may exert anti-tumor effects by directly affecting tumor cell growth or survival via the c-Met receptor tyrosine kinase pathway. We therefore suggest that KRC-408 is a novel therapeutic candidate effective against gastric cancers that overexpress c-Met.     

PP121, a dual inhibitor of tyrosine and phosphoinositide kinases,inhibits anaplastic thyroid carcinoma cell proliferation and migration

The tyrosine and phosphoinositide kinases play crucial roles in the regulation of many cancer cell processes including cell survival and cell motility. Anaplastic thyroid carcinoma (ATC) is a rare and deadly type of thyroid cancer, and so far, there are no effective therapeutic compounds for ATC. Herein, we investigate the anticancer activities of PP121, a dual inhibitor of tyrosine and phosphoinositide kinases, in ATC therapy. We found that PP121 is effective at suppressing cell viability, inducing cell apoptosis, and inhibiting cell migration and invasion. The potential anticancer mechanism for PP121 might be its inhibitory effects on phosphatidylinositol 3-kinase (PI3K)/Akt signaling pathways in ATC cells. Furthermore, PP121 is effective at suppressing ATC tumor growth in vivo. In summary, our studies suggest that PP121 might be a promising therapeutic compound for ATC treatment, which might shed new light on ATC therapy.     

Rapamycin inhibits proliferation of human neuroblastoma cells without suppression of MycN

MYCN and insulin-like growth factor (IGF) system are important for the pathogenesis and development of neuroblastoma. We previously reported evidence of a direct linkage between MycN and the IGF system in KP-N-RT human neuroblastoma cells, where IGF-I induced both MycN expression at the RNA level and G1-S cell cycle progression through the IGF-I receptor (IGF-IR)/ MEK/ mitogen-activated protein kinase (MAPK) pathway (A. Misawa et al., Cancer Res, 2000; 60:64-9). Our data also showed the possibility of a potent IGF-IR downstream signal cascade that accelerates progression into the S-phase, other than the MAPK pathway. In this study, we further investigated the role of this alternative pathway in the growth of neuroblastoma cells. A phosphoinositide 3-kinase (PI3K) inhibitor wortmannin blocked IGF-I-mediated induction of MycN. Our data suggest that the inhibition of MycN by wortmannin was transmitted through the MAPK pathway. Progression of the cell cycle from G1 to S phase was inhibited up to 90% by wortmannin or rapamycin, an inhibitor of mTOR, which acts downstream of PI3K. Despite its effects on induction of MycN and on progression through S phase, wortmannin did not block proliferation of neuroblastoma cells. On the other hand, rapamycin inhibited both IGF-I-induced cell cycle progression and cell proliferation in complete medium, although it had no effect on IGF-I-mediated MycN induction. Our study indicates maintenance of cell proliferation requires mTOR function, which is independent of MycN induction in human neuroblastoma cells.