RGD肽联合丝裂霉素C对荷人膀胱癌T24裸鼠肿瘤生长的抑制作用

目的:探讨纤维连接蛋白(FN)拮抗剂精氨酸-甘氨酸-天冬氨酸三肽(RGD)联合丝裂霉素C(MMC)对荷膀胱癌T24裸鼠肿瘤生长的抑制作用。方法:建立荷膀胱癌T24裸鼠模型(n=32)。全部成瘤后随机分为4组:对照组(n=8):瘤体局部注射生理盐水,1次/3d;RGD组(n=8):瘤体局部注射RGD6μg/g,1次/3d;MMC组(n=8):瘤体局部注射MMC2μg/g,1次/3d;RGD MMC组(n=8):瘤体局部注射RGD6μg/g和MMC2μg/g,1次/3d。连续治疗5周后处死动物,取出肿瘤称重,计算抑瘤率。结果:RGD MMC、MMC组抑瘤率分别为77.6%和67.4%;与对照组比较差异均有统计学意义(P<0.05);RGD MMC组、MMC组肿瘤生长速度明显慢于对照组和RGD组;RGD MMC组、MMC组肿瘤体积分别为(351.4±86.5)mm3及(520.6±121.9)mm3,均明显小于对照组(1613.9±460.2)mm3(P<0.05);RGD MMC组、MMC组肿瘤重量分别为(366.5±93.4)mg及(534.7±135.6)mg,均明显小于对照组(1639.5±479.2)mg(P<0.05)。结论:FN拮抗剂RGD肽可协同MMC抑制荷膀胱癌T24裸鼠肿瘤的生长;RGD肽联合MMC治疗膀胱移行细胞癌可能有较好的临床应用前景。     

RGD肽对猪去细胞心脏瓣膜表面修饰的研究

目的 检测促黏附分子RGD肽(精-甘-天冬氨酸)表面修饰去细胞瓣天然支架可行性.方法 应用酶和去污剂法制备猪去细胞主动脉瓣,固相法合成含RGD短肽GRGDSPC.实验组采用化学交联剂Sulfo-LC-SPDP使GRGDSPC肽与之结合,去细胞瓣直接混合短肽和单纯去细胞瓣两组作对照.X射线光电子能谱法(XPS)支架材料表面分析.结果 XPS法显示,对照组未检出硫元素,实验组检出硫元素电子结合能中间峰位在163.1～165.7eV,提示二硫键形成,证明Sulfo-LC-SPDP使GRGDSPC肽成功固定于去细胞瓣表面.结论 通过化学交联法实现RGD肽对去细胞瓣表面修饰,有望促进组织工程心脏瓣膜构建.     

PRP及RGD联合修饰表面改性后仿生基质对ADSCs生物学行为的调控

目的 评估富血小板血浆(platelet rich plasma,PRP)及精氨酸-甘氨酸-天冬氨酸(Arg-Gly-Asp,RGD)联合修饰表面改性后支架的细胞生物学特征,验证优化界面整合的方法.方法 兔脂肪基质干细胞成骨诱导化,nβ-TCP/Cs/PCL仿生基质Nd:YAG激光处理,表面改性及细胞接种:A组(PRP凝胶加RGD修饰表面改性基质加ADSCs)、B组(RGD修饰表面改性基质加ADSCs)、C组(表面改性基质加ADSCs)、D组(未表面改性基质加ADSCs);第1、4、8、12、16、20、24、28天,显微镜和电镜、共聚焦技术观察和检测细胞的存活率、增殖活力、Westen blot测定碱性磷酸酶及Ⅰ型胶原蛋白表达活性,分析Runx2与OPG表达.结果 A组细胞生长旺盛、细胞外基质丰富,存活率高于其它组(88.16±1.29,P＜0.05),增殖活力、碱性磷酸酶及Ⅰ型胶原水平均高于其它组(0.92±0.13,87.27±3.08,93.27±3.91,P＜0.05),Runx2和OPG表达显著.结论 PRP及RGD修饰联合支架表面改性能促进细胞增殖,为理想的骨整合方法.     

αυβ3抗体对人肝癌细胞系MHCC97的黏附抑制作用

整合素介导的黏附行为与肿瘤的发生、发展、浸润及转移等过程密不可分。研究结果表明，整合素是细胞表面受体家族。通过识别细胞外基质中的RGD序列（Arg-Cly-Asp，精氨酸、甘氨酸、天冬氨酸）介导细胞与细胞外基质之间的黏附。     

精氨酸—甘氨酸—天门冬氨酸肽在急性肾衰中的潜在治疗作用

精氨酸－甘氨酸－天门冬氨酸三肽（ＲＧＤ）是整合系受体与细胞外基质配体或基膜成份配体相结合的识别位点，在急性缺血性肾衰时可抑制肾小管上皮细胞之间的粘附，从而预防肾小管阻塞，改善急性肾衰预后，具有潜在临床应用价值，本文综述了急性肾衰整合受体分布异常及其病理生理学意义，ＲＧＤ肽结合位点的组织分布，ＲＧＤ肽对急性肾衰的潜在治疗作用。     

MAGE-1抗原肽致敏DC活化淋巴细胞对裸鼠肝癌移植瘤的免疫防护作用

目的　观察黑色素瘤 1基因 (MAGE 1)抗原肽致敏树突状细胞 (DC)所活化的淋巴细胞(CTL)对人肝癌HCC移植瘤的抑制和消退作用 ,评估临床治疗HCC的可行性和有效性。　方法BEL 74 0 2HCC细胞于 30只裸鼠背部皮下接种 ,建立裸鼠HCC移植瘤模型 ,其中 2 2只成瘤 ;用MAGE 1九肽致敏DC所活化的淋巴细胞 (1× 10 6)注入肿瘤部位皮下 (治疗组A ,n =5 ) ,其余 17只随机分成 5组 (B、C、D、E、F) ,用其他不同性质的细胞治疗 ,观察各组肿瘤生长情况并进行病理学分析和统计学处理 ,阐明特异性CTL对肿瘤的作用机制。　结果　 (1)A组HCC移植瘤均停止生长并趋于缩小 ,荷瘤裸鼠观察期内无死亡 ;而其他 5组肿瘤均快速生长 ,大部分荷瘤裸鼠 2周内死亡。MAGE 1九肽致敏DC所活化淋巴细胞能显著抑制HCC移植瘤生长 ,促使肿瘤消退 (P <0 0 1)。 (2 )A组移植肿瘤广泛坏死 ,肿瘤细胞广泛凋亡。　结论　MAGE 1九肽致敏DC有抑制HCC生长 ,促进HCC消退 ,防止肿瘤转移、复发的作用。肿瘤细胞凋亡增强是DC肿瘤免疫的可能机制。MAGE 1九肽联合DC可作为治疗HCC的新型疫苗。     

含精氨酸-甘氨酸-天冬氨酸肽白细胞介素-24突变体蛋白对肝癌细胞抑制作用

目的 观察含精氨酸-甘氨酸-天冬氨酸(RGD)肽模体的白细胞介素(IL)-24突变体蛋白(RGD-IL-24)对肝癌细胞的抑制作用.方法 肝癌HepG2细胞分别加入各10μl的RGD-IL-24(8 mg/L)、IL-24(8 mg/L)和磷酸盐缓冲液(PBS),噻唑蓝(MTT)比色法检测HepG2细胞生长抑制作用;DAPI染色检测HepG2细胞凋亡;免疫印迹法检测HepG2细胞bax、bcl-2及Caspase-3蛋白表达;黏附实验检测与HepG2细胞的靶向黏附.结果 RGD-IL-24、IL-24治疗4 d后HepG2细胞存活率分别为(0.219±0.015)、(0.397±0.009),与对照组(0.823±0.013)比较差异有统计学意义(P<0.01).RGD-IL-24、IL-24治疗组细胞凋亡率分别为(0.631±0.027)、(0.472±0.031),与对照组(0.082±0.013)比较差异有统计学意义(P<0.01).RGD-IL-24抑制HepG2细胞生长、诱导凋亡效果均比IL-24显著增强(P<0.05).与IL-24治疗组比较,RGD-IL-24治疗组HepG2细胞促凋亡蛋白bax增加、抗凋亡蛋白bcl-2减少、活化Caspase-3蛋白量增加.黏附实验证实RGD-IL-24与HepG2细胞的靶向结合作用增强.结论 含RGD肽模体的IL-24蛋白能通过与肝癌HepG2细胞的靶向结合增强其凋亡诱导作用.     

细胞黏附介导的耐药在肿瘤的研究

临床上肿瘤细胞获得性耐药仍然是肿瘤化疗失败的一个重要原因.大量研究认为细胞外基质在介导肿瘤获得性耐药中起主要作用.整合素表达于多种细胞表面,是细胞和细胞外基质相互作用的桥梁.近年来,整合素粘附介导的细胞耐药机制开始受到关注.本文综述了整合素及细胞外基质在获得性耐药中的作用.     

组织因子途径抑制物2在肿瘤发生转移和侵袭中的作用

细胞外基质(extracellularmatrix,ECM)降解是肿瘤发生浸润转移过程中的关键一步,肿瘤细胞分泌的多种丝氨酸蛋白酶包括基质金属蛋白酶(matrixmetallopoteinases,MMPs)参与细胞外ECM降解。组织因子途径抑制物2(tissuefactorpathwayinhibitor-2,TFPI-2)是一种具有32000丝氨酸蛋白酶抑制物,可抑制包括纤溶酶、胰蛋白酶、MMPs在内的多种蛋白酶。越来越多的研究表明,TFPI-2通过降解MMPs等抑制肿瘤转移、降低肿瘤的侵袭转移能力。TFPI-2在抑制肿瘤细胞迁徙及浸润转移过程中发挥重要作用,可作为一种潜在的基因治疗靶点。     

含精氨酸-甘氨酸-天冬氨酸肽白细胞介素-24突变体蛋白的表达及其生物活性

目的 获得含精氨酸-甘氨酸-天冬氨酸(RGD)肽的白细胞介素(IL)-24突变体(RGD-IL-24)蛋白,研究其生物活性.方法 用重叠聚合酶链反应(PCR)技术在IL-24 cDNA序列中引入甘氨酸密码子GGC,构建RGD-IL-24 cDNA,将其克隆人质粒pET28a(+)获得pET28a/RGD-IL-24.pET28a/RGD-IL-24转化菌株BL21(DE3),采用亲合层析纯化蛋白,透析复性.SDS-PAGE电泳和Western blot鉴定RGD-IL-24蛋白.酶联免疫吸附试验(ELISA)法检测RGD-IL-24刺激外周血单核细胞(PBMC)产生IL-6、肿瘤坏死因子(TNF)-α和干扰素(IFN)-γ的能力来测定RGD-IL-24免疫活性.细胞黏附实验检测RGD-IL-24与多种肿瘤细胞结合特性.结果 成功获得RGD-IL-24基因,并构建表达质粒pET28a/RGD-IL-24.表达的RGD-IL-24蛋白约占菌体总蛋白的30%,纯化后蛋白纯度超过90%.RGD-IL-24处理的人PBMC培养上清IL-6、TNF-α和IFN-γ浓度(ng/L)分别为(780.5 ±98.3、2399.1 ±113.2、2130.1 ±98.6),显著高于IL-24处理组(551.0±52.1、1982.5 ±138.2、1762.9 ±119.8).黏附实验证实RGD-IL-24能增强与肿瘤A549、HeLa和ACHN细胞靶向结合作用.结论 含RGD肽的RGD-IL-24蛋白免疫生物活性及与肿瘤细胞靶向结合能力较IL-24明显增强.     

Integrin signaling via RGD peptides and anti-beta1 antibodies confers resistance to apoptosis in islets of Langerhans

Islet transplantation is associated with a high rate of early graft failure caused by early immune attack and poor functionality of islets. Apoptosis of islet cells appears soon after islet isolation and primarily involves the beta-cell. The purpose of this study was to determine the effect of ligation to extracellular matrix (ECM) proteins on survival of the islets of Langerhans following islet isolation. Islets that had been cultured for 24 h on collagen type I showed an islet survival of 59.7 +/- 8.7%, while islets that had been cultured on collagen type IV and laminin showed an islet survival of 88.6 +/- 10.3 and 94.3 +/- 5.6%, respectively. Islets that had been pretreated with anti-beta1 antibodies and argenin-glycin-aspartic acid (RGD) peptides showed a decrease in the level of apoptosis by a factor of 2.5 and 3.1, respectively, and an increase of phospho-Akt Ser 473 activity by a factor of 3.1 and 2.9, respectively, compared with untreated islets. When detached from their natural ECM surrounding in the pancreas, islet cells undergo apoptosis, unless islets are cultured on collagen IV or laminin or treated with anti-beta1 integrin antibodies or RGD peptides to mimic ECM ligation. These results indicate that inhibition of anoikis may offer opportunities to improve function and viability of islet cells.     

In Vivo Analysis of Arg‐Gly‐Asp Sequence/Integrin α5β1‐Mediated Signal Involvement in Embryonic Enchondral Ossification by Exo Utero Development System

Enchondral ossification is a fundamental mechanism for longitudinal bone growth during vertebrate development. In vitro studies suggested that functional blockade with RGD peptides or with an antibody that interferes with integrin α5β1–ligand interactions inhibited pre‐hypertrophic chondrocyte differentiation. The purpose of this study is to elucidate in vivo the roles of the integrin α5β1‐mediated signal through the Arg‐Gly‐Asp (RGD) sequence in the cell–extracellular matrix (ECM) interaction in embryonic enchondral ossification by an exo utero development system. We injected Arg‐Gly‐Asp‐Ser (RGDS) peptides and anti‐integrin α5β1 antibody (α5β1 ab) in the upper limbs of mouse embryos at embryonic day (E) 15.5 (RGDS‐injected limbs, α5β1 ab‐injected limbs), and compared the effects on enchondral ossification with those found in the control limbs (Arg‐Gly‐Glu‐Ser peptide‐, mouse IgG‐, or vehicle‐injected, and no surgery) at E16.5. In the RGDS‐injected limbs, the humeri were shorter and there were fewer BrdU‐positive cells than in the control limbs. The ratios of cartilage length and area to those of the humerus were higher in the RGDS‐injected limbs. The ratios of type X collagen to type 2 collagen mRNA and protein (Coll X/Coll 2) were significantly lower in the RGDS‐injected limbs. In those limbs, TUNEL‐positive cells were hardly observed, and the ratios of fractin to the Coll X/Coll 2 ratio were lower than in the control limbs. Furthermore, the α5β1 ab‐injected limbs showed results similar to those of RGDS‐injected limbs. The present in vivo study by exo utero development system showed that RGDS and α5β1 ab injection decreased chondrocyte proliferation, differentiation, and apoptosis in enchondral ossification, and suggested that the integrin α5β1‐mediated ECM signal through the RGD sequence is involved in embryonic enchondral ossification. © 2014 American Society for Bone and Mineral Research.     

Mechanism of perturbation of integrin-mediated cell-matrix interactions by reactive carbonyl compounds and its implication for pathogenesis of diabetic nephropathy

Perturbation of interactions between cells and the extracellular matrix (ECM) of renal glomeruli may contribute to characteristic histopathological lesions found in the kidneys of patients with diabetic nephropathy. However, the mechanism by which the diabetic conditions may affect cell-ECM interactions is unknown. Existing hypotheses suggest a role of glucose in direct modification of ECM. Here, we have demonstrated that carbonyl compound methylglyoxal (MGO) completely inhibited endothelial cell adhesion to recombinant alpha3 noncollagenous 1 domain of type IV collagen mediated via a short collagenous region containing RGD (Arg-Gly-Asp) sequence as well as binding of purified alpha(v)beta(3) integrin to this protein. Specific MGO adducts of the arginine residue were detected within RGD sequence using mass spectrometry. Modification by carbonyl compounds glyoxal or glycolaldehyde had similar but smaller effects. MGO strongly inhibited adhesion of renal glomerular cells, podocytes, and mesangial cells to native collagen IV and laminin-1 as well as binding of collagen IV to its major receptor in glomerular cells, alpha(1)beta(1) integrin. In contrast, modification of these proteins by glucose had no effect on cell adhesion. Pyridoxamine, a promising drug for treatment of diabetic nephropathy, protected cell adhesion and integrin binding from inhibition by MGO. We suggest that in diabetes, perturbation of integrin-mediated cell-matrix interactions occurs via the modification of critical arginine residues in renal ECM by reactive carbonyl compounds. This mechanism may contribute to the development of diabetic nephropathy.     

Human osteoblast-like cell adhesion on titanium substrates covalently functionalized with synthetic peptides

Biomaterials to be used for the production of endosseous devices in dental, orthopedic and maxillo-facial applications, might be designed to support, guide and enhance osteoblast adhesion. Cell recruitment onto biomaterial surface is a fundamental step within the complex process responsible for implant osseointegration; this process involves several proteins from the extra cellular matrix (ECM), cytoskeleton and cell membrane. A new strategy to improve endosseous implant integration is based on preparing biomimetic surfaces able to present adhesive factors to cells. Osteoblast adhesion takes place by at least two different mechanisms: the most investigated one implies the interaction with RGD sequences via cell-membrane integrin receptors; a further mechanism concerns the interaction between cell-membrane heparan sulfate proteoglycans and heparin-binding sites of ECM proteins. In the present study two different biomimetic surfaces were obtained by covalently grafting two adhesive peptides on oxidized titanium substrates after silanization: an RGD-containing peptide and a peptide mapped on human vitronectin. The two sequences are known to act via different adhesive mechanisms. The amount of human osteoblasts adhered onto peptide-enriched or not enriched titanium oxidized surfaces and the strength of cell binding were estimated, thus comparing the capacity of the bioactive substrates in promoting cell adhesion.     

Fibronectin induces ureteric bud cells branching and cellular cord and tubule formation

BACKGROUND: The extracellular matrix (ECM) protein fibronectin is involved in several stages of embryogenesis. Fibronectin exerts its effect through interaction with cellular integrin and nonintegrin receptors. METHODS: We investigated the effect of fibronectin on branching and tubulogenesis of ureteric bud cells in a three-dimensional gel culture system. Primary ureteric bud cells from mouse embryos at gestation 11 days (E11) were isolated and established in culture. Fibronectin and integrin subunits were localized using immunoperoxidase staining. RESULTS: In three-dimensional collagen type I gel culture of ureteric bud cell, fibronectin dose dependently induces cord and tubule formation. Both ureteric bud cells and ureteric bud branches in embryonic kidney express the same multiple integrin subunits that include beta(1), beta(3), alpha(3), alpha(4) and alpha(v). Embryonic kidneys examined at E12, E14, and E16 days of gestation express fibronectin in the undifferentiated mesenchyme especially next to ureteric bud branches and in the interstitium around glomerulotubular structures and blood vessels. Fibronectin expression was similar at the tips and stalks of branching ureteric bud. Fibronectin expression is maximum at E12 and decreases with advanced gestation. Cultured ureteric bud cells also express fibronectin. RGD peptides inhibit cord and tubular formation in the three-dimensional gel. Anti-alpha(3)beta(1) antibody partially inhibits fibronectin-induced cord and tubule formation. Hepatocyte growth factor (HGF), fibroblast growth factor (FGF), and glial cell line-derived neurotrophic factor (GDNF) induce ureteric bud cell cord formation in three-dimensional gel. The effects of growth factors are delayed and quantitatively less compared to the effect of fibronectin. CONCLUSION: Fibronectin induces ureteric bud cells branching and tubulogenesis through interaction with multiple integrin receptors. Cultured ureteric bud cells express fibronectin and the origin of fibronectin at mesenchyme-ureteric bud interface is likely both the metanephric mesenchyme and ureteric bud epithelium. Addition of individual neutralizing antibodies to beta(1), beta(3), alpha(3), alpha(4,)alpha(6) and alpha(v) integrin subunits does not block the effect of fibronectin. Only an antibody to alpha(3)beta(1) integrin substantially blocks the effect of fibronectin. Other mechanisms, including unidentified integrins, are likely involved in fibronectin-induced cord and tubule formation.     

RGD peptide-induced cell death of chondrocytes and synovial cells

Background  Small peptides including the Arg-Gly-Asp (RGD) motif have been used in studies on cell-extracellular matrix (ECM) attachment due to their ability to disturb integrin-mediated attachment on the cell surface. As another biological action of RGD peptides, several reports have shown that RGD peptides are incorporated into cytoplasm and induce apoptosis by direct activation of caspase-3. This study evaluated the effect of RGD peptides on chondrocytes and synovial cells and studied the involvement of caspases. Methods  Chondrocytes and synovial cells were isolated and cultured from the knee joints of New Zealand White rabbits. Cells were incubated in serum-free medium with peptides (RGD, RGDS, GRGDSP, GRGDNP, RGES), and the survival rates were evaluated. The rate of apoptotic cells was measured by flow cytometry in cells treated with RGDS, GRGDSP, and RGES. Caspase-3, -8 and -9 activity was measured in cells treated with RGDS and GRGDSP. Osteochondral explants harvested from rabbits were also incubated with RGD peptides (RGDS, GRGDSP, and GRGDNP), and the survival rate of chondrocytes was evaluated. Results  The survival rate of cultured chondrocytes was significantly decreased in the GRGDSP- and GRGDNP-treated groups. The survival rate of synovial cells was significantly decreased with four of the RGD peptides (RGD, RGDS, GRGDSP, and GRGDNP) at 5 mM, and in the RGDS- and GRGDSP-treated groups at 1 mM. Flow cytometric assay revealed increases of apoptotic chondrocytes with GRGDSP and increases of apoptotic synovial cells with RGDS and GRGDSP. Caspase-3 was activated in chondrocytes treated with GRGDSP and it was also activated in synovial cells treated with RGDS and GRGDSP. Caspases-8 and -9 were not activated in chondrocytes or in synovial cells. The survival rate of chondrocytes in explants decreased in the superficial layer with all three RGD peptides (RGDS, GRGDSP, and GRGDNP) and in the middle layer with GRGDSP. Conclusions  RGD peptides induced apoptosis in cultured chondrocytes as well as in cells in cartilage explants and synovial cells, presumably through direct activation of caspase-3.     

Collagen IV significantly enhances migration and transplantation of embryonic stem cells: involvement of α2β1 integrin-mediated actin remodeling

Embryonic stem (ES) cell transplantation represents a potential means for the treatment of degenerative diseases and injuries. As appropriate distribution of transplanted ES cells in the host tissue is critical for successful transplantation, the exploration of efficient strategies to enhance ES cell migration is warranted. In this study we investigated ES cell migration under the influence of various extracellular matrix (ECM) proteins, which have been shown to stimulate cell migration in various cell models with unclear effects on ES cells. Using two mouse ES (mES) cell lines, ESC 26GJ9012-8-2 and ES-D3 GL, to generate embryoid bodies (EBs), we examined the migration of differentiating cells from EBs that were delivered onto culture surfaces coated with or without collagen I, collagen IV, Matrigel, fibronectin, and laminin. Among these ECM proteins, collagen IV exhibited maximal migration enhancing effect. mES cells expressed α2 and β1 integrin subunits and the migration enhancing effect of collagen IV was prevented by RGD peptides as well as antibodies against α2 and β1 integrins, indicating that the enhancing effect of collagen IV on cell migration was mediated by α2β1 integrin. Furthermore, staining of actin cytoskeleton that links to integrins revealed well-developed stress fibers and long filopodia in mES cells cultured on collagen IV, and the actin-disrupting cytochalasin D abolished the collagen IV-enhanced cell migration. In addition, pretreatment of undifferentiated or differentiated mES cells with collagen IV resulted in improved engraftment and growth after transplantation into the subcutaneous tissue of nude mice. Finally, collagen IV pretreatment of osteogenically differentiated mES cells increased osteogenic differentiation-like tissue and decreased undifferentiation-like tissue in the grafts grown after transplantation. Our results demonstrated that collagen IV significantly enhanced the migration of differentiating ES cells through α2β1 integrin-mediated actin remodeling and could promote ES cell transplantation efficiency, which may be imperative to stem cell therapy.     

实体恶性肿瘤循环肿瘤细胞检测的研究进展

恶性实体肿瘤远处转移是导致肿瘤患者死亡的主要原因。目前,恶性肿瘤的诊断主要依赖影像学检查、病理学检查及肿瘤标志物等。随着精准医疗时代的到来,循环肿瘤细胞(CTC)检测技术应运而生,已成为肿瘤学界的研究热点,使人类对恶性肿瘤的检测达到单细胞水平,从而被视为恶性肿瘤的"液体活检"样本,并具有无创、多次、实时获取及整体性等优点,在实体恶性肿瘤的诊断、治疗及病情监测等方面具有独特优势。本文通过综述相关文献,分析了常见CTC检测技术的特点及其临床应用现状,旨在为进一步完善CTC检测技术,指导其在科研及临床中的应用提供参考。     

Anti-beta1 integrin antibody reduces surgery-induced adhesion of colon carcinoma cells to traumatized peritoneal surfaces

OBJECTIVE: To study the mechanisms behind surgery-induced augmentation of tumor outgrowth. SUMMARY BACKGROUND DATA: Surgery provides the best chance of cure for most primary intra-abdominal carcinomas. Effective treatment is however relatively frequent complicated by peritoneal recurrences, which often originate from free-floating intraperitoneal tumor cells that implant on peritoneal surfaces. We previously reported that surgical trauma promotes development of peritoneal metastases. METHODS: Evaluation of adhesion of CC531s rat colon carcinoma cell line intraperitoneally after laparotomy using in vivo, ex vivo, and in vitro models. Also, human ex vivo models were used to study peritoneal tumor cell adhesion. RESULTS: Peritoneal imprints of operated rats showed that direct damaging of the peritoneum resulted in enhanced adhesion of rat CC531 colon carcinoma cells to submesothelial extracellular matrix (ECM) proteins in vivo, which was confirmed by electron microscopy. Additionally, the inflammatory reaction of the peritoneal cavity led to retraction of mesothelial cells, hereby also exposing ECM at peritoneal surfaces that had not been traumatized directly. Furthermore, we demonstrated that beta1 integrin subunits represented the primary mediators involved in adherence to either isolated ECM components or excised traumatized rat and human peritoneum. Importantly, incubation of CC531s cells with anti-beta1 integrin antibodies resulted in a significant decrease of tumor cell adhesion in vivo. CONCLUSIONS: Surgical trauma results in exposure of ECM at directly and nondirectly damaged peritoneal surfaces, leading to increased beta1 integrin-dependent tumor cell adhesion. Perioperative therapies, which aim to block beta1 integrin subunits, might therefore serve as new clinical tools for the prevention of peritoneal recurrences.     

Cytoprotective Effects of a Cyclic RGD Peptide in Steatotic Liver Cold Ischemia and Reperfusion Injury

The serious need for expanding the donor population has attracted attention to the use of steatotic donor livers in orthotopic liver transplantation (OLT). However, steatotic livers are highly susceptible to hepatic ischemia–reperfusion injury (IRI). Expression of fibronectin (FN) by endothelial cells is an important feature of hepatic response to injury. We report the effect of a cyclic RGD peptide with high affinity for the α5β1, the FN integrin receptor, in a rat model of steatotic liver cold ischemia, followed by transplantation. RGD peptide therapy ameliorated steatotic IRI and improved the recipient survival rate. It significantly inhibited the recruitment of monocyte/macrophages and neutrophils, and depressed the expression of pro-inflammatory mediators, such as inducible nitric oxide synthase (iNOS) and interferon (IFN)-γ. Moreover, it resulted in profound inhibition of metalloproteinase-9 (MMP-9) expression, a gelatinase implied in leukocyte migration in damaged livers. Finally, we show that RGD peptide therapy reduced the expression of the 17-kDa active caspase-3 and the number of apoptotic cells in steatotic OLTs. The observed protection against steatotic liver IRI by the cyclic RGD peptides with high affinity for the α5β1 integrin suggests that this integrin is a potential therapeutic target to allow the successful utilization of marginal steatotic livers in transplantation.