肿瘤微环境与肿瘤转移

肿瘤转移与肿瘤微环境中成纤维细胞、转化生长因子、肿瘤相关巨噬细胞、趋化因子及其受体、凝血酶等多种因素密切相关。成纤维细胞通过促进肿瘤血管生成、促进癌细胞与细胞外基质黏附、促进细胞外基质降解等环节参与肿瘤的转移。TGF-β是由巨噬细胞、间质细胞和肿瘤细胞产生,它能对抗血管内皮的紧密连接和黏附连接,使毛细血管壁完整性受到破坏,从而导致毛细血管通透性增加,使肿瘤细胞从血管中游出进入器官组织中形成种植转移。肿瘤相关性巨噬细胞可合成和分泌EGF等细胞因子,引导肿瘤细胞穿越血管壁,促进肿瘤的转移。趋化因子及其受体对肿瘤细胞的迁移起着决定性的作用。凝血酶能通过影响微环境中其他细胞的行为而为肿瘤转移提供一个相容的环境。明晰肿瘤转移与肿瘤微环境的关系,进而明确在肿瘤发生、发展、转移过程中发挥重要作用的关键分子,寻找其相对应的靶点,对于肿瘤的诊断及治疗具有重要的作用。     

肿瘤干细胞微环境与肿瘤转移

肿瘤干细胞(cancer stem cell,CSC)是肿瘤组织中一小部分具有自我更新、无限增殖能力和多向分化潜能的肿瘤细胞,是肿瘤发生、发展的根源,也可能是起始肿瘤转移发生的根本原因。由细胞外基质(extra cellular matrix,ECM)、血管微环境和骨髓微环境等组成了复杂的CSC微环境,为CSC的生长提供条件;同时,CSC还能招募、激活间充质干细胞等特殊类型的细胞形成适合CSC生长的微环境。并且,CSC微环境能分泌低氧诱导因子(hypoxia-inducible factor,HIF)、IL-1β等细胞因子,激活相关信号通路,通过诱导血管生成及抑制免疫等途径参与CSC的侵袭、转移等。近年来,靶向CSC微环境治疗肿瘤转移逐渐引起了研究人员的注意,尝试靶向一些分子和通路,如IL-6、IL-8及其受体、核因子-κB(nuclear factor-κB,NF-κB)和乙醛脱氢酶1(aldehyde dehydrogenase 1,ALDH1)等,借此抑制卵巢癌、乳腺癌中CSC的增殖,已经取得了一定成果。因此,针对CSC及其微环境的干扰的治疗将可能成为肿瘤治疗的新方向。     

肿瘤微环境的组成及其在肿瘤转移中的作用

肿瘤微环境是肿瘤细胞赖以生存的复杂环境,主要是由多种不同的细胞外基质和基质细胞组成。肿瘤微环境的成分与肿瘤细胞之间存在相互刺激作用,从而促进肿瘤进展和肿瘤细胞的转移。研究表明肿瘤细胞和基质细胞通过两种方式共同演变：基质变化导致上皮细胞转化,或者转化的上皮细胞可能以旁分泌方式激活基质细胞。肿瘤细胞引起细胞外基质重建,并参与肿瘤生长,进一步引起肿瘤侵袭和播撒。基因表达谱研究发现肿瘤基质中的动态变化有利于肿瘤细胞转移,以基质变化为标准的肿瘤分类能够预测其临床预后和转移靶器官。     

肿瘤微环境——肿瘤转移的关键因素

肿瘤转移是癌症治疗失败和患者死亡的主要原因,其分子机制复杂,涉及多步骤、多阶段、多基因的变化。作为肿瘤细胞赖以生存的场所,肿瘤微环境在肿瘤转移过程中起到至关重要的作用。因此,研究肿瘤微环境与肿瘤转移的动态关系,阐明微环境中不同因子在转移过程中的分子机制是抑制肿瘤转移的关键。     

髓源性抑制细胞在构筑转移前微环境促肿瘤转移中的作用

肿瘤细胞持续存活是肿瘤转移过程中的主要限速环节.与肿瘤微环境类似,转移前器官的局部微环境(转移前微环境)为肿瘤细胞的存活提供了适宜的环境,是肿瘤细胞在远端器官持续存活、增殖的重要条件.髓源性抑制细胞(myeloid-derived suppressor cells,MDSCs)是这一环境中的关键成分,其构筑的促增殖、炎症、免疫抑制及血管重塑的转移前微环境在肿瘤细胞的种殖、转移灶的形成过程中具有重要作用,是抗肿瘤转移治疗的潜在靶点.该研究主要介绍MDSCs构筑转移前微环境的机制及相关信号通路,为干预转移前微环境的抗肿瘤转移研究提供参考.     

肿瘤微环境与肿瘤的进展和转移

1肿瘤微环境 肿瘤是由异型细胞组成的,具有自我无限增殖及侵袭的能力。新证据显示,肿瘤的形成和进展不单只与肿瘤细胞本身有关,它是一种由多种异形细胞相互作用而形成的复杂组织,由此产生肿瘤微环境的概念。肿瘤微环境内存在各种不同类型的细胞,包括内皮细胞及其前体细胞、周细胞、平滑肌细胞、成纤维细胞、肿瘤相关性成纤维细胞、肌纤维母细胞、中性粒细胞、嗜酸性粒细胞、嗜碱性粒细胞、肥大细胞、T、B淋巴细胞、自然杀伤细胞和抗原提呈细胞（APCs）如巨噬细胞和树突状细胞。     

肿瘤微环境中的炎性机制与肿瘤转移

炎性微环境是肿瘤微环境中影响肿瘤复发转移的关键因素之一.肿瘤炎性微环境可以通过调节上皮细胞向间充质细胞转变,启动肿瘤转移;可以通过降解细胞外基质从而破坏细胞外基质膜促进肿瘤细胞的侵袭;同时,炎性微环境促进肿瘤血管的新生为肿瘤的发生发展提供保障.     

肿瘤预转移微环境形成的研究进展

摘 要：原发灶肿瘤通过诱导并改造未来转移器官,使之成为适合循环肿瘤细胞（circulatingtumor cells,CTCs）定植的微环境,即肿瘤预转移微环境（pre-metastatic niche,PMN）。PMN形成包括血管渗漏及通透性改变、凝血异常、细胞外基质重塑、骨髓源细胞的迁移和募集、免疫抑制等过程,其中肿瘤来源外泌体,肿瘤来源可溶性因子（tumor-derived soluble factors,TDSFs）,骨髓源细胞（bone marrow-derived cells,BMDCs）等在这过程中至关重要。全文结合国内外最新研究成果,对外泌体、TDSFs、BMDCs等在PMN形成过程中发挥的作用进行综述,探讨其涉及的具体机制以及可能发现针对肿瘤转移治疗的新靶点和可能面临的挑战。     

细胞微环境microRNAs在肿瘤侵袭转移中的作用

肿瘤微环境是肿瘤发生、发展的重要组成成分,微环境中microRNAs作为原癌基因或抑癌基因能够进入靶细胞,调控相关靶基因的表达和功能,从而影响微环境的构成,并在肿瘤细胞侵袭和转移中发挥重要作用。因此,microRNAs在肿瘤诊断治疗中具有诱人的应用前景。     

树突状细胞诱导的抗肿瘤免疫预防肝癌转移

目的 探讨树突状细胞（ＤＣ）体外诱导的抗肿瘤免疫在肝癌患者体内的抗转移作用。方法 直癌患者外周血ＤＣ及Ｔ淋巴细胞,ＨｅｐＧ２细胞抗原激活ＤＣ,粒／巨噬细胞集落刺激因子和白细胞介素－４联合刺激ＤＣ,ＤＣ诱导自体Ｔ淋巴细胞增殖分化为细胞毒性Ｔ细胞（ＣＴＬ）,ＤＣ及其诱导的ＣＴＬ回输肝癌患者,检测肝癌患者外周血ＡＦＰ为ｍＲＮＡ。结果 ＡＦＰ ｍＲＮＡ阳性组经ＤＣ及其诱导的ＣＴＫ,治疗２月后,治疗组９例Ａ     

BNIPL-2 promotes the invasion and metastasis of human hepatocellular carcinoma cells

Enhanced cell migration and invasion play key roles in cancer metastasis. However, the molecules involved in this process are not fully understood. In this study, a full-length human BNIPL-2 (Bcl-2/adenovirus E1B 19 kDa interacting protein 2 like-2) cDNA was transfected into human hepatocellular carcinoma cells with low metastatic potential (MHCC97-L). The in vitro and in vivo effects of BNIPL-2 on cell invasion and metastasis were examined. In vitro analysis showed that the overexpression of BNIPL-2 increases cell invasion and promotes cell migration. The rates of intrahepatic and pulmonary metastasis in nude mice were also increased. Cdc42 activation assays and immunoblot analysis indicated that the activation of Cdc42 and the upregulation of CD44 were involved in the metastasis of cancer cells. The overexpression of BNIPL-2 promotes the invasion and metastasis of MHCC97-L cells. Thus, BNIPL-2 is a gene related with cancer metastasis.     

肝癌血管生成的研究

肝癌是比较典型的多血管肿瘤,其生长和转移依赖肿瘤血管生成。栓塞已有的血管(肝动脉栓塞化疗),和阻断血管生成(索拉菲尼)的治疗已是临床标准的肝癌治疗方法。最近的证据显示侵袭性较强的肝癌可在癌周诱导特殊的环境     

Rho kinase phosphorylation promotes ezrin-mediated metastasis in hepatocellular carcinoma

During progression of hepatocellular carcinoma, multiple genetic and epigenetic alterations act to posttranslationally modulate the function of proteins that promote cancer invasion and metastasis. To define such abnormalities that contribute to liver cancer metastasis, we carried out a proteomic comparison of primary hepatocellular carcinoma and samples of intravascular thrombi from the same patient. Mass spectrometric analyses of the liver cancer samples revealed a series of acidic phospho-isotypes associated with the intravascular thrombi samples. In particular, we found that Thr567 hyperphosphorylation of the cytoskeletal protein ezrin was tightly correlated to an invasive phenotype of clinical hepatocellular carcinomas and to poor outcomes in tumor xenograft assays. Using phospho-mimicking mutants, we showed that ezrin phosphorylation at Thr567 promoted in vitro invasion by hepatocarcinoma cells. Phospho-mimicking mutant ezrinT567D, but not the nonphosphorylatable mutant ezrinT567A, stimulated formation of membrane ruffles, suggesting that Thr567 phosphorylation promotes cytoskeletal-membrane remodeling. Importantly, inhibition of Rho kinase, either by Y27632 or RNA interference, resulted in inhibition of Thr567 phosphorylation and a blockade to cell invasion, implicating Rho kinase-ezrin signaling in hepatocellular carcinoma cell invasion. Our findings suggest a strategy to reduce liver tumor metastasis by blocking Rho kinase-mediated phosphorylation of ezrin.     

Twist promotes the migration of hepatocellular carcinoma cells

OBJECTIVE To study the effect of the Twist gene on the migration of human hepatocellular carcinoma cells and the possible mechanisms involved. METHODS RT-PCR was used to detect expression of the Twist gene in primary （Hep11） and recurrent （Hep12） cell lines from the same HCC patient. Hep11 cells were stably transfected with Twist-cDNA, and Hep12 cells were transiently transfected with Twist RNAi plasmid. Cell migration assays were performed on Twist up-regulated Hep11 cells and Twist RNAi Hep12 cells. RT- PCR and Western blot were used to test the expression of EMT markers. RESULTS Twist was expressed higher level and had increased migration capability in recurrent Hep12 cells than those in primary Hep11 cells. Cell models （Twist-Hep11） in which Twist protein was steadily and highly expressed were obtained. Compared with pcDNA3-Hep11 cells, migration of Twist-Hep11 cells was clearly increased. However, migration of Twist RNAi （Si-Twist-Hep12） Hep12 cells were reduced. Overexpression of Twist in Hep11 cells promoted expression of N-cad and vimentin. CONCLUSION These results indicate that Twist promotes the migration of hepatocellular carcinoma cells in vitro and may play an important role in the upregulation of mesenchymal markers.     

CTHRC1基因在人肝癌中高表达并促进MHCC97L肝癌细胞的转移

目的：分析CTHRC1基因在人肝癌组织和肝癌细胞株中的表达情况及其对MHCC97L肝癌细胞转移能力的影响。方法：采用northem blot、RT—PCR和荧光定量PCR分析人肝癌组织和肝癌细胞株中CTHRC1 mRNA水平。构建包含CTHRC1基因编码框的真核表达载体pCMV-3Tag-CTHRC1，通过体外实验分析CTHRC1在MHCC97L细胞中过表达对MHCC97L细胞迁移、侵袭等转移能力的影响。结果：Northern blot、RT—PCR和荧光定量PCR结果显示，14例肝癌患者中11例存在癌组织CTHRC1 mRNA表达水平高于癌旁组织，8种肝癌细胞株中5种肝癌细胞株存在着CTHRC1的高表达。当CTHRC1过表达后，MHCC97L细胞的迁移及侵袭能力显著增强（P〈0．001）。结论：CTHRC1基因在人肝癌组织和人肝癌细胞株中存在着高表达，同时该基因可使肝癌细胞MHCC97L的转移能力明显增强，提示CTHRC1基因可能在肿瘤转移中起重要作用。     

Downregulation of microRNA-100 enhances the ICMT-Rac1 signaling and promotes metastasis of hepatocellular carcinoma cells

Metastasis is responsible for rapid recurrence of hepatocellular carcinoma (HCC) and poor survival of HCC patients. Here we showed that miR-100 downregulation in HCC tissues was significantly associated with venous invasion, advanced TNM stage, tumor nodule without complete capsule, poorer cell differentiation, and shorter recurrence-free survival. Both gain- and loss-of-function studies showed that miR-100 dramatically suppressed the ability of HCC cells to migrate and to invade through Matrigel in vitro. Analyses using mouse orthotopic xenograft model further revealed that xenografts of miR-100-stable-expressing HCC cells displayed a significant reduction in pulmonary metastasis, compared with control group. Subsequent investigations revealed that miR-100 directly inhibited the expression of isoprenylcysteine carboxyl methyltransferase (ICMT) and ras-related C3 botulinum toxin substrate 1 (Rac1) by binding to their 3′-UTRs, and in turn suppressed lamellipodia formation and matrix metallopeptidase 2 (MMP2) activation. Furthermore, knockdown of ICMT and Rac1 phenocopied the anti-metastasis effect of miR-100, whereas overexpression of the constitutively active Rac1 (Q61L) antagonized the function of miR-100. Taken together, miR-100 represses metastasis of HCC cells by abrogating the ICMT-Rac1 signaling. Downregulation of miR-100 contributes to HCC metastasis and the restoration of miR-100 is a potential strategy for cancer therapy.