3,5-二氯苯基双胍抑制黑色素瘤肺转移的裸鼠体内药效学研究

目的 确认整合素αvβ3新型抑制剂3,5-二氯苯基双胍对人黑色素瘤肺转移的抑制作用.方法 应用前期建立的人黑色素瘤裸鼠肺转移模型,观察3,5-二氯苯基双胍的治疗效果.裸鼠尾静脉接种黑色素瘤细胞(第1天)后,于第5、9、13、17和21天给予该药物治疗.50 d实验结束,处死裸鼠并取完整的肺组织,Bouin氏液固定24 h后根据肺表面癌结节的大小和数量给予评分,以此评价肺转移的程度.结果 3,5-二氯苯基双胍6、12 mg/kg和24 mg/kg治疗组的转移分数分别为(55.25±13.60)、(35.13±17.36)和(12.83±11.44),与溶剂对照组(转移分数是82.50±17.72)相比具有明显差异(P＜0.05).阳性对照组的转移分数为(11.50±10.44)(P＜0.05 vs 溶剂对照组),阴性对照组和PBS对照组的转移分数分别为(88.50±17.21)、和(88.87±11.29) (P ＞0.05 vs溶剂对照组).结论 3,5-二氯苯基双胍在裸鼠体内能够明显抑制黑色素瘤肺转移,并呈现一定的剂量依赖性.     

C57BL/6 J小鼠黑色素瘤肺转移模型的构建

目的探讨建立C57BL/6 J小鼠黑色素瘤肺转移模型的影响因素,包括肿瘤的接种方式、细胞接种数量和成瘤周期。方法体外培养小鼠黑色素瘤细胞B16F10。1)取6~8周龄,雄性小鼠18只,随机分三组,每组6只,分别采取尾静脉注射、腹腔注射和皮下注射方式,每只小鼠注射100μL(3×10~6个细胞)B16F10细胞悬液,2周后,解剖小鼠并观察黑色素瘤的生长和转移情况;2)分3组,同上,经尾静脉分别注射3×10~6个细胞、1×10~6个细胞、3×10~5个细胞,2周后,解剖小鼠并观察黑色素瘤的生长和转移情况;3)分3组,同上,尾静脉注射1×10~6个细胞,分别于1周、2周、3周解剖小鼠,观察黑色素瘤的生长和转移情况。结果 1)尾静脉注射小鼠黑色素瘤细胞,小鼠发生肺转移的成功率为100%,而腹腔注射和皮下注射未发生肺转移。2)接种小鼠黑色素瘤细胞数量为1×10~6时,发生肺部转移的黑色素瘤细胞数量适中;接种细胞数量为3×10~6时,发生肺部转移的黑色素瘤细胞数量过多;接种细胞数量为3×10~5时,发生肺部转移的黑色素瘤细胞数量较少。3)尾静脉注射1×10~6个小鼠黑色素瘤细胞,饲养2周后,可以观察到黑色素瘤细胞明显的肺部转移,且不会导致小鼠死亡;饲养3周,黑色素瘤细胞肺部转移数量过多,且小鼠死亡过半;饲养1周,黑色素瘤细胞肺部转移数量较少。结论经尾静脉注射1×10~6个小鼠黑色素瘤细胞,生长2周时间,为构建C57BL/6 J小鼠黑色素瘤肺转移模型的推荐方法。     

脉络膜黑色素瘤中整合素αvβ3表达的研究

目的：整合素αvβ3整合素家族成员之一,是一类跨膜粘附分子,其在多种肿瘤细胞及新生内皮血管细胞中高表达而在成熟血管内皮、上皮细胞及正常细胞中表达较低或无表达。基于这些特征,整合素αvβ3年来成为分子影像研究的热点之一。鉴于整合素αvβ3人眼脉络膜黑色素瘤中是否存在表达尚不可知,本课题拟研究整合素αvβ3人脉络膜黑色素瘤中表达情况,为以整合素αvβ3基础的分子显像提供理论基础。方法：培养人源脉络膜黑色素瘤细胞株OCM-1,使用蛋白免疫印迹方法检测整合素αvβ3OCM-1中表达水平,并使用免疫组化方法检测人脉络膜黑色素瘤病理切片中整合素αvβ3达分布。结果：蛋白免疫印迹实验表明在OCM-1细胞株中存在整合素αvβ3达,其表达水平介于已知高表达整合素αvβ3头颈鳞癌细胞株HEP-2和较低表达整合素αvβ3头颈鳞癌细胞株CNE-1之间,免疫组化方法检测人脉络膜黑色素瘤病理切片中也存在整合素αvβ3达。结论：人脉络膜黑色素瘤中具有整合素αvβ3达,可以为后期研究基于整合素αvβ3分子显像技术提供依据。     

整合素αVβ3与病毒感染

整合素αvβ3是一类表达于细胞表面的跨膜糖蛋白粘附分子,由α和β两种Ⅰ型膜蛋白亚单位以非共价键形式连接形成异源二聚体分子。整合素αvβ3可表达于多种细胞,细胞外信号通过不同分子可与其发生相互作用,经整合素αvβ3将细胞外信号传递至细胞内,引起钙离子、Pyk2和磷脂酰肌醇-3(PI-3)激酶等细胞内信号发生变化。整合素αvβ3在血管生成、胚胎发育、肿瘤转移、免疫应答等多种生理和病理过和中发挥着重要的作用。近几年,整合素αvβ3与病毒感染的相关研究进展迅速,本文就整合素αvβ3与病毒感染作一综述。1整合素αvβ3概述1·1整合素αv…     

α_vβ_3整合素与恶性肿瘤侵袭转移关系的研究进展

整合素家族是细胞粘附分子的重要种类之一,主要作用是介导细胞与细胞之间、细胞与细胞外基质之间的粘附效应。医学研究证实整合素家族与肿瘤的侵袭及远处转移等生物学行为密切相关。整合素αvβ3是整合素家族中的一种重要分子,肿瘤血管内皮细胞中αvβ3的表达水平对肿瘤侵袭转移及血管生成有着重要作用,调节αvβ3的表达水平可明显影响肿瘤的侵袭转移及肿瘤组织中新生血管的形成。深入研究整合素αvβ3的分子调节机制可以为肿瘤治疗提供新的治疗靶点。     

骨唾液酸蛋白通过整合素αvβ3调控ILK信号通路

旨在探究骨唾液酸蛋白(BSP)是否通过整合素αvβ3对整合素连接激酶(ILK)信号通路进行调控。BSP基因沉默乳腺癌MDA-MB-231细胞,流式细胞仪在细胞水平检测BSP不同水平的细胞株中整合素αvβ3的表达量。Western blotting检测磷酸化ILK水平的变化,MTT法检测细胞增殖能力。与对照组231BO-Scrambled细胞相比,BSP基因沉默组231BO-BSP27细胞中整合素αvβ3的表达水平明显下调(61.32±1.94)%(P<0.01)。整合素αvβ3鼠抗单克隆抗体(LM609)处理前的BSP基因沉默组231BO-BSP27细胞与21BO-Scrambled细胞相比,ILK磷酸化水平下调明显(39.38±1.38)%(P<0.01);LM609处理后的231BO-BSP27细胞与21BO-Scrambled细胞相比,ILK磷酸化水平下调明显(33.78±1.51)%(P<0.01)。向乳腺癌细胞231BO-scrambled和231BO-BSP27中添加LM609,MTT试验结果显示两株乳腺癌细胞的增殖能力均有降低(P<0.05)。BSP通过整合素αvβ3对乳腺癌MDA-MB-231细胞ILK信号通路进行调控,并影响细胞增殖。     

重组FN多肽CH50抑制黑色素瘤B16细胞体内转移的研究

目的研究重组纤黏连蛋白（FN）多肽CH50对小鼠黑色素瘤B16细胞体内转移的影响,以探讨CH50多肽抑制肿瘤转移的可能分子机制。方法体外培养黑色素瘤B16细胞,用荧光染料CFSE标记,接种脾脏后24h取脾、肝、肺做冰冻切片,观察肿瘤细胞在3种组织中的侵袭情况。从脾脏接种B16细胞,建立体内肿瘤转移动物模型,采用基于流体动力学的体内基因转染方法于小鼠体内表达CH50多肽,RT-PCR检测CH50mRNA在肝组织的表达,Western印迹检测CH50多肽的表达。通过比较原位肿瘤结节及转移结节在数量、大小、分布上的差异及检测原位肿瘤组织中MMP-2、MMP-9表达差异,观察CH50多肽的治疗效果。结果注射24h后即可在脾脏形成荧光结节。pCH510质粒通过尾静脉注射后,可在肝组织中检测到CH50mRNA及CH50多肽的表达。从脾脏接种B16细胞后第14天可在脾脏形成原发肿瘤,至第35天肝脏表面已形成转移瘤结节,成功建立了体内器官问（脾转肝）肿瘤转移动物模型。体内转染表达CH50多肽能抑制肿瘤生长、侵袭和转移,抑制原位肿瘤结节中MMP-2、MMP-9的表达。结论CH50多肽可以通过对MMP-2、MMP-9蛋白表达的抑制作用来抑制黑色素瘤B16细胞的成瘤能力和体内侵袭、转移能力。     

肺癌转移瘤动物模型的建立

目的通过尾静脉注射,建立一种符合临床特征的肺腺癌转移瘤动物模型,为下一步的肺腺癌转移机制的研究提供可靠的实验造模方法。方法取对数生长期的A549细胞,11只SPF级、4~6周龄BALB/c裸鼠,分别以1×106个细胞/只注射入裸鼠尾静脉。接种后每天观察小鼠状态。分别于接种肿瘤细胞后第4、5、6、7周随机处死2只,余3只小鼠处于濒死状态时处死。解剖小鼠,观察肺部有无转移、转移结节的数目及全身其他器官的转移情况,并做病理取材,HE染色观察。结果注射过程中小鼠均存活。未处死的3只分别于第11、13、14周出现恶液质。第4周肺部未见转移结节;第5周出现镜下肺部转移结节;第6周肉眼可见肺部转移结节;第7周转移结节数增多;第11周出现纵隔淋巴结转移。第11、13、14周出现肺部结构大量破坏,弥漫性的肿瘤细胞浸润,出现淋巴结浸润,病理证实为腺癌。结论通过尾静脉注射A549细胞可以成功建立人肺腺癌转移瘤模型。     

siRNA干扰MMP-9和FAK双基因抑制小鼠黑色素瘤生长和在体迁移

目的:观察干扰MMP-9和FAK双基因对恶性黑色素瘤高转移细胞B16F10体内转移的影响。方法:构建PGV102-MMP9-siRNA、PGV102-FAK-siRNA重组质粒载体,脂质体^TM2000介导转染小鼠黑色素瘤B16F10细胞,RT-PCR检测基因的干扰效果;建立C57BL/6小鼠皮下移植瘤模型观察细胞在体成瘤和肿瘤的生长情况,常规组织切片,H&E染色观察肿瘤组织病理学特征;经C57BL/6小鼠尾静脉注射细胞5×10⁵个/只,24天后计数小鼠肺转移结节数评价肿瘤细胞在体迁移能力。结果:RT-PCR结果表明,重组质粒转染细胞组的MMP-9和FAK的mRNA水平显著低于正常细胞组(P<0.01),转染细胞组C57BL/6小鼠皮下成瘤的肿瘤生长速率、黑色素瘤肺转移结节数明显低于正常细胞组(P<0.01)。结论:干扰B16F10细胞MMP-9和FAK双基因可明显抑制小鼠体内恶性肿瘤的生长和迁移。     

脉络膜黑色素瘤中整合素α_vβ_3表达的研究

目的:整合素α_vβ_3为整合素家族成员之一,是一类跨膜粘附分子,其在多种肿瘤细胞及新生内皮血管细胞中高表达而在成熟血管内皮、上皮细胞及正常细胞中表达较低或无表达。基于这些特征,整合素α_vβ_3近年来成为分子影像研究的热点之一。鉴于整合素α_vβ_3在人眼脉络膜黑色素瘤中是否存在表达尚不可知,本课题拟研究整合素α_vβ_3在人脉络膜黑色素瘤中表达情况,为以整合素α_vβ_3为基础的分子显像提供理论基础。方法:培养人源脉络膜黑色素瘤细胞株OCM-1,使用蛋白免疫印迹方法检测整合素α_vβ_3在OCM-1中表达水平,并使用免疫组化方法检测人脉络膜黑色素瘤病理切片中整合素α_vβ_3表达分布。结果:蛋白免疫印迹实验表明在OCM-1细胞株中存在整合素α_vβ_3表达,其表达水平介于已知高表达整合素α_vβ_3的头颈鳞癌细胞株HEP-2和较低表达整合素α_vβ_3的头颈鳞癌细胞株CNE-1之间,免疫组化方法检测人脉络膜黑色素瘤病理切片中也存在整合素α_vβ_3表达。结论:人脉络膜黑色素瘤中具有整合素α_vβ_3表达,可以为后期研究基于整合素α_vβ_3的分子显像技术提供依据。     

Src, PKCα, and PKCδ are required for αvβ3 integrin-mediated metastatic melanoma invasion

Background

Integrins, cell-surface receptors that mediate adhesive interactions between cells and the extracellular matrix (ECM), play an important role in cancer progression. Expression of the vitronectin receptor αvβ3 integrin correlates with increased invasive and metastatic capacity of malignant melanomas, yet it remains unclear how expression of this integrin triggers melanoma invasion and metastasis.

Results

Two melanoma cell lines C8161.9 and M14 both express high levels of αvβ3 integrin and adhere to vitronectin. However, only the highly metastatic C8161.9 cells are capable of invading vitronectin-enriched Matrigel in an αvβ3-depenent manner. Elevated levels of PKCα and PKCδ, and activated Src were detected specifically in the highly metastatic melanoma cells, but not in the low metastatic M14 cells. Inhibition of Src or PKC activity suppressed αvβ3-dependent invasion. Furthermore, over expression of Src or PKCα and PKCδ was sufficient to confer αvβ3-dependent invasiveness to M14 cells. Stress fiber formation and focal adhesion formation were almost completely absent in C8161.9 cells compared to M14 cells. Inhibition of Src signaling was sufficient to restore normal actin architecture, and resulted in decreased p190RhoGAP phosphorylation and enhanced RhoA activity. Src had no effect on Rac activity. Loss of PKCα expression, but not PKCδ, by siRNA inhibited Rac and PAK activity as well as invasiveness. Loss of PKCα restored focal adhesion formation and partially restored stress fiber formation, while loss of PKCδ primarily restored stress fibers.

Conclusion

The misregulated expression of PKCα and PKCδ and elevated Src activity in metastatic melanoma cells is required for efficient αvβ3-mediated invasion. PKCα and Src enhance αvβ3-mediated invasion in part by increasing the GTPase activity of Rac relative to RhoA. PKCα influences focal adhesion formation, while PKCδ controls stress fibers.     

Interaction between integrin alpha(5) and fibronectin is required for metastasis of B16F10 melanoma cells

In this study, we report the role of integrin alpha(5) in promoting melanoma metastasis. The alpha(5) expression was remarkably elevated in highly metastatic B16F10 melanoma cells compared to lowly metastatic B16F1 cells, whereas no significant changes were detected in those of integrin alpha(4), alpha(v), and beta(1) subunits. Neutralization of alpha(5) with anti-alpha(5) antibody significantly suppressed the potential of B16F10 cells for pulmonary metastasis in mice and inhibited cell adhesion or spreading to fibronectin in vitro. Furthermore, loss of the interaction between alpha(5) and fibronectin diminished cell survival and induced apoptosis in B16F10 cells. Above results provide clear evidence that integrin alpha(5) is positively correlated with melanoma metastasis and might be an anti-melanoma target.     

Integrin αvβ6 Promotes Lung Cancer Proliferation and Metastasis through Upregulation of IL-8–Mediated MAPK/ERK Signaling

Lung cancer is notorious for high morbidity and mortality around the world. Interleukin (IL)-8, a proinflammatory chemokine with tumorigenic and proangiogenic effects, promotes lung cancer cells growth and migration and contributes to cell aggressive phenotypes. Integrin αvβ6 is a receptor of transmembrane heterodimeric cell surface adhesion, and its overexpression correlates with poor survival from non–small cell lung cancer. However, the cross talk between αvβ6 and IL-8 in lung cancer has not been characterized so far. Herein, human lung cancer samples were analyzed, and it revealed that the immunohistochemical and mRNA expression of integrin αvβ6 was significantly correlated with the expression of IL-8. Furthermore, in vitro, integrin αvβ6 increased cell proliferation, migration, and invasion by impairing the expressions of MMP-2 and MMP-9 and inhibited cell apoptosis in human lung cancer cells A549 and H460. In addition, integrin αvβ6 upregulated IL-8 expression through activating MAPK/ERK signaling. The in vivo experiment showed that integrin αvβ6 promoted tumor growth in xenograft model mice by accelerating tumor volume and reducing apoptosis. Meanwhile, lung metastasis model experiment suggested that integrin αvβ6 stimulated tumor metastasis with the increase of lung/total weight and tumor nodules. Simultaneously, integrin αvβ6 upregulated IL-8 expression detected by both Western blots and immunohistochemistry, along with the activation of MAPK/ERK signaling. Overall, these data suggested that, in vitro and in vivo, integrin αvβ6 promoted lung cancer proliferation and metastasis, at least in part, through upregulation of IL-8–mediated MAPK/ERK signaling. Thus, the inhibition of integrin αvβ6 and IL-8 may be the key for the treatment of lung cancer.     

Suppression of Mouse Melanoma Metastasis by EA-1, A Monoclonal Antibody Specific for α6 Integrins

The rat monoclonal antibody (mAb) termed EA-1 was originally selected for its capacity to block the adhesion of T lymphocyte progenitors to mouse thymic endothelium. Here we show that the mAb EA-1 recognizes the α6 chain of α6β1 and α6β4 integrins. Both molecules are present at a high level on the luminal and basolateral side of vascular endothelium and α6β1 integrin is expressed on the highly metastatic cell lines B16/129 (melanoma) and KLN-205 (carcinoma). These lung specific tumors bind preferentially to lung frozen sections, and EA-1 blocked this interaction in vitro. Moreover, mAb EA-1 inhibited experimental metastasis to the lung of B16/129 cells injected intravenously. Metastasis in vivo was blocked when the antibody was injected into mice before or simultaneously with the melanoma cells, as well as when melanoma cells were precoated with EA-1 before injection. We suggest that α6 integrins play a dual role in the metastatic process, mediating the adhesion of tumor cells to the luminal surface of the endothelium and the adhesion to laminin in the subendothelial extracellular matrix during extravasation. Despite the fact that α6 integrins are laminin receptors, EA-1 did not interfere with melanoma cell binding to laminin fragments. Our antibody EA-1 may therefore recognize a binding domain on α6 integrins of a novel ligand involved in cell-cell interaction.     

Inhibition of metastasis of syngeneic murine melanoma in vivo and vasculogenesis in vitro by monoclonal antibody C11C1 targeted to domain 5 of high molecular weight kininogen

Metastasis of malignant tumors is a major cause of morbidity and mortality. Inhibition of tumor growth in distant organs is of clinical importance. We have demonstrated that C11C1, a murine monoclonal antibody to the light chain region of high molecular weight kininogen (HK), reduces growth of murine multiple myeloma in normal mice and human colon cancer in nude mice. C11C1 inhibits angiogenesis by reducing tumor microvascular density by blocking binding of HK to endothelial cells. We now evaluate the anti-metastatic effect of C11C1 on C57BL/6 mouse lung metastatic model using B16F10 melanoma cells. The tail veins of mice were injected with 0.5 × 10⁶ cells of melanoma B16F10. One group received C11C1 and the other received saline (control) intraperitoneally. When mice were killed at 28 days, 6 of 10 control mice had detectable metastatic pulmonary nodules which stained positive with an antibody against S-100 protein, a tumor antigen present in malignant melanoma cells. In the C11C1 groups, none of the mice showed metastatic foci in their lungs. We showed that C11C1 inhibits endothelial cell tube formation in a 3-D collagen fibrinogen gel model by inhibiting the rate of cleavage of HK by plasma kallikrein without changing the binding affinity for HK. These studies demonstrate that a monoclonal antibody to HK has the potential to prevent metastasis with minimal side effects.     

RGD cadherins and α2β1 integrin in cancer metastasis: A dangerous liaison

We propose a new cadherin family classification comprising epithelial cadherins (cadherin 17 [CDH17], cadherin 16, VE-cadherin, cadherin 6 and cadherin 20) containing RGD motifs within their sequences. Expression of some RGD cadherins is associated with aggressive forms of cancer during the late stages of metastasis, and CDH17 and VE-cadherin have emerged as critical actors in cancer metastasis. After binding to α2β1 integrin, these cadherins promote integrin β1 activation, and thereby cell adhesion, invasion and proliferation, in liver and lung metastasis. Activation of α2β1 integrin provokes an affinity increase for type IV collagen, a major component of the basement membrane and a critical partner for cell anchoring in liver and other metastatic organs. Activation of α2β1 integrin by RGD motifs breaks an old paradigm of integrin classification and supports an important role of this integrin in cancer metastasis. Recently, synthetic peptides containing the RGD motif of CDH17 elicited highly specific and selective antibodies that block the ability of CDH17 RGD to activate α2β1 integrin. These monoclonal antibodies inhibit metastatic colonization in orthotopic mouse models of liver and lung metastasis for colorectal cancer and melanoma, respectively. Hopefully, blocking the cadherin RGD ligand capacity will give us control over the integrin activity in solid tumors metastasis, paving the way for development of new agents of cancer treatment.     

Integrin αXβ2 Is a Leukocyte Receptor for Candida albicans and Is Essential for Protection against Fungal Infections

The opportunistic fungus Candida albicans is one of the leading causes of infections in immunocompromised patients, and innate immunity provides a principal mechanism for protection from the pathogen. In the present work, the role of integrin α(X)β(2) in the pathogenesis of fungal infection was assessed. Both purified α(X)β(2) and α(X)β(2)-expressing human epithelial kidney 293 cells recognized and bound to the fungal hyphae of SC5314 strain of C. albicans but not to the yeast form or to hyphae of a strain deficient in the fungal mannoprotein, Pra1. The binding of the integrin to the fungus was inhibited by β-glucans but not by mannans, implicating a lectin-like activity in recognition but distinct in specificity from that of α(M)β(2). Mice deficient in α(X)β(2) were more prone to systemic infection with the LD(50) fungal inoculum decreasing 3-fold in α(X)β(2)-deficient mice compared with wild-type mice. After challenging i.v. with 1.5 × 10(4) cell/g, 60% of control C57BL/6 mice died within 14 d compared with 100% mortality of α(X)β(2)-deficient mice within 9 d. Organs taken from α(X)β(2)-deficient mice 16 h postinfection revealed a 10-fold increase in fungal invasion into the brain and a 2-fold increase into the liver. These data indicate that α(X)β(2) is important for protection against systemic C. albicans infections and macrophage subsets in the liver, Kupffer cells, and in the brain, microglial cells use α(X)β(2) to control fungal invasion.