间皮细胞损伤在胃癌腹膜转移中的作用

胃癌是我国发病率和死亡率均占第一位的恶性肿瘤。手术后仍有50%-60%的病人因腹膜转移而死亡。目前针对癌转移“种子—土壤”学说中“土壤”的研究方兴未艾,尤其对于在胃癌腹膜转移过程中,腹膜间皮细胞的形态、结构、功能的改变,及其影响因子可能成为胃癌腹膜转移研究的新方向。1间皮细胞在癌腹膜转移的改变1.1腹膜转移的屏障—间皮细胞间皮由广泛的间皮单层覆盖于浆膜面和器官表面,起初被认为只有润滑和防止组织粘连的作用。随着研究的深入,间皮细胞的特性不断被认识,目前间皮细胞的功能涉及抗原递呈、再生修复、纤维组织的清除、胞质合成…     

大肠癌术后如何预防肠粘连?

肠粘连是腹部手术后经常出现的一种并发症,它是指腹腔的壁层腹膜或内脏表面与肠表面发生的粘连。据统计,腹部外科手术后约有60%～90%的患者会出现不同程度的肠粘连,手术次数越多、损伤越大,肠粘连的机会也就越多。大部分肠粘连的患者其症状一般都比较轻微,轻     

胃癌MKN45细胞培养液上清对腹膜间皮细胞损伤的实验研究

目的:建立胃癌腹膜转移早期间皮细胞的损伤模型,探讨胃癌腹膜转移早期癌细胞对间皮细胞的损伤与细胞凋亡的联系,以及凋亡程度与相关蛋白表达。方法:将人胃癌细胞培养液上清,与人腹膜间皮细胞系HMrSV5共培养。观察间皮细胞形态、增殖改变,透射电镜观察细胞凋亡,流式细胞仪和荧光染色判断凋亡比例。免疫印迹法检测凋亡相关蛋白Bcl-2和Bax表达情况。结果:接触胃癌培养液上清24h后,间皮细胞大片脱落并出现典型凋亡表现。胃癌细胞的分泌物明显抑制间皮细胞的生长。胃癌细胞培养液上清可诱导间皮细胞凋亡、抑制细胞增殖,呈程度-时间依赖性地抑制间皮细胞抗凋亡蛋白Bcl-2的表达;并能增加促凋亡蛋白Bax表达。结论:胃癌细胞在腹膜转移早期可以通过其分泌物诱导间皮细胞损伤、凋亡,凋亡机制与Bcl-2和Bax的失调有关。提示保护间皮细胞,抗间皮细胞凋亡在胃癌腹膜转移治疗中可能有一定应用价值。     

胃癌的腹膜亚临床转移检测及阻断治疗研究

进行期胃癌根治术后腹膜转移约占４０％～５０％。是死亡的主要原因之一犤１犦。其途径是：１）癌细胞浸透胃浆膜；２）向腹腔脱落，在腹腔内环境作用下形成有生物活性的脱落癌细胞（ECC）；３）与腹膜粘附着床，增殖形成癌结节。转移病灶一旦形成，即为临床转移，治疗十分困难。因此将胃癌腹膜转移诊断和预测提高到亚临床水平，采取有效的阻断治疗，具有重要的临床意义。近年来，我们对此作了较为系统的基础与临床应用研究。１腹膜组织形态学及腹膜转移的病理生物学研究正常的腹膜是由单层间皮细胞及其下方细胞外基质（ExtracellularMatr…     

胃癌细胞上清液对腹膜间皮细胞的作用

目的:探讨胃癌细胞上清液对腹膜间皮细胞的作用。方法:用胃癌细胞上清液处理人腹膜间皮细胞后,通过HE染色法观察腹膜间皮细胞的形态学变化,免疫细胞化学法检测腹膜间皮细胞中上皮细胞标志蛋白E-cadherin、cytokeratin和间质化标志蛋白N-cadherin、fibronectin的表达。将胃癌细胞上清液注射入裸鼠腹腔,应用免疫组织化学法和蛋白质印迹法检测裸鼠腹膜组织中上皮细胞标志蛋白E-cadherin、cytokeratin和间质化标志蛋白N-cadherin、fibronectin的表达。结果:经胃癌细胞上清液处理的腹膜间皮细胞呈梭形,细胞脱落,细胞间连接减少;胃癌细胞上清液处理的腹膜间皮细胞E-cadherin和cytokeratin的表达水平低于未处理的空白对照组和用无血清DMEM培养液处理的实验对照组(P值均<0.05),而N-cadherin和fi bronectin的表达水平则高于未处理的空白对照组和用无血清DMEM培养液处理的实验对照组(P值均<0.05)。腹腔注射胃癌细胞上清液的裸鼠腹膜组织E-cadherin和cytokeratin的表达水平低于未处理的空白对照组和腹腔注射无血清DMEM培养液的实验对照组(P值均<0.05),而N-cadherin和fi bronectin的表达水平则高于未处理的空白对照组和腹腔注射无血清DMEM培养液的实验对照组(P值均<0.05)。结论:胃癌细胞上清液可使腹膜间皮细胞失去原有的上皮细胞生物学行为,而获得间质细胞的生物学行为。     

二甲双胍通过AMPK/Smad3信号通路抑制卵巢癌腹腔间皮细胞的间皮-间质转化

目的:探讨二甲双胍对人腹腔间皮细胞（human peritoneal mesothelial cells,HPMC）间皮-间质转化的影响及其可能机制,以及进一步对卵巢癌细胞系SKOV3系膜清除能力的影响。方法:搜集2018年02月至2021年02月襄阳市第一人民医院妇产科正常网膜组织和高级别浆液性卵巢癌网膜转移灶标本进行免疫组织化学检测Calretinin表达情况;分离、培养原代人腹腔间皮细胞并进行Calretinin流式鉴定;Western blot和Transwell实验检测二甲双胍或肿瘤上清处理正常患者来源HPMC后其间皮-间质转化相关蛋白（E-cadherin、Vimentin、α-SMA）及迁移能力改变情况;Western blot检测二甲双胍、Smad3抑制剂及AMPK干扰处理前后正常来源原代人腹腔间皮细胞中MMP2、E-cadherin、Vimentin、p-AMPK和p-Smad3的表达情况;SKOV3球体的系膜清除实验验证二甲双胍预处理人腹膜间皮细胞系HMrSV5对SKOV3系膜清除能力的影响。结果:正常网膜中Calretinin表达于腹腔侧表面的腹腔内皮细胞,卵巢癌网膜转移灶表面Calretinin表达缺失,肿瘤间质中高表达Calretinin;分离培养的肿瘤来源原代人腹腔间皮细胞流式检测表现为CD326-CD45-CD31-Calretinin+;二甲双胍能够抑制肿瘤上清诱导的正常来源原代HPMC的间皮-间质转化及迁移;二甲双胍能够抑制肿瘤上清诱导的正常来源原代HPMC中Smad3/MMP2通路活化和E-cadherin表达,并依赖于AMPK信号活化;二甲双胍预处理HMrSV5通过AMPK信号的介导抑制了HMrSV5的间皮-间质转化进而间接抑制了SKOV3的系膜清除能力。结论:卵巢癌转移灶中的间质成分部分来源于腹腔间皮细胞,二甲双胍通过AMPK调控的Smad3信号通路抑制其间皮-间质转化,进而抑制卵巢癌肿瘤细胞的系膜清除。     

结直肠癌微环境诱导腹膜间皮细胞凋亡的体外实验研究

目的:创建发生腹膜转移早期时结直肠癌对人腹膜间皮细胞HMrSV5的损伤模型,探讨结直肠癌细胞对腹膜间皮细胞的影响及凋亡相关蛋白的表达。方法:将人结直肠癌细胞培养液上清加入到人腹膜间皮细胞系HMrSV5。共培养后,光镜下观察间皮细胞的形态变化、CCK-8检测增殖改变、流式细胞仪判断凋亡比例、Western-blot检测凋亡相关蛋白Bcl-2和Bax、Transwell小室检测受损间皮细胞对结直肠癌细胞的影响。结果:结直肠癌细胞培养液上清接触间皮细胞后,发生了形态改变,细胞的增殖受到了抑制,凋亡蛋白Bcl-2与Bax表达失调。同时,受损间皮能够促进结直肠癌细胞的迁移。结论:结直肠癌细胞在发生腹膜转移的早期时候,就可以通过其分泌物促使间皮细胞发生凋亡,凋亡的发生与Bcl-2和Bax的失调有关;同时受损间皮能够反作用于结直肠癌细胞,促进其迁移。我们从中意识到,保护间皮细胞免受损伤,在预防和治疗结直肠癌腹膜转移中或许能起到一定的作用。     

乳斑肿瘤相关巨噬细胞诱导人腹膜间皮HMR-sv5细胞损伤的机制研究

  目的   研究胃癌细胞对巨噬细胞的诱导作用, 分析活化巨噬细胞对间皮细胞的损伤作用及机制。   目法   人正常胃腺上皮细胞系GES-1及人低分化胃癌细胞系SGC-7901与人单核巨噬细胞THP-1共培养, 诱导后者分化, 研究后者对人腹膜间皮细胞HMR-sv5的损伤作用及分子机制。   结果   胃癌细胞诱导THP-1形成肿瘤相关巨噬细胞(TAM), M1型巨噬细胞表面抗原的表达显著下调, 而M2表型的表面抗原明显上调, 细胞形态也发生明显改变。TAM显著抑制正常间皮细胞生长, 促进间皮细胞凋亡和上皮间质转化。   结论   胃癌细胞诱导巨噬细胞发生表型和功能转化, 进而导致间皮细胞发生EMT和凋亡, 促进形成腹膜转移癌。      

胃癌细胞与腹膜间皮相互作进用促腹膜纤维化致腹膜转移的研究

  目的   研究间皮细胞对胃癌细胞的抵御作用, 模拟游离癌细胞在接触腹膜前通过其分泌物导致的腹膜增厚、纤维化的过程, 同时观察了间皮细胞对胃癌细胞迁移及侵袭能力的反作用。   方法  用荧光显微镜观察共培养时间皮细胞对胃癌细胞的抵御作用; 体内实验观察腹膜变化; 电镜、光镜下观察体外实验中间皮层在胃癌-腹膜相互作用中的损伤和细胞骨架变化; 采用Millicell小室共培养观察间皮细胞对胃癌细胞迁移及侵袭能力的反作用。   结果  正常间皮细胞可防止肿瘤细胞对于腹膜的粘附, 受损脱落后胃癌细胞可轻易粘附。体内外实验均显示接触胃癌细胞上清后腹膜间皮细胞受损、凋亡, 并且受损残余的间皮可以反作用于癌细胞, 使其迁移转移力提高。   结论  正常间皮细胞可以抵御胃癌细胞的侵袭, 受损伤刺激后的间皮细胞可以反作用于胃癌细胞促进其迁移及侵袭。      

TGF-β1小干扰RNA影响人腹膜间皮细胞黏附胃癌细胞株SGC-7901的研究

目的:观察人腹膜间皮细胞转染TGFβ1小干扰RNA后对胃癌细胞株SGC7901黏附的变化,探讨其治疗腹膜转移的作用。方法:使用线性化的pcPURβicassette质粒构建针对TGFβ1基因的siRNA表达载体;采用胰蛋白酶EDTA消化法,从人的腹膜组织中分离腹膜间皮细胞。将TGFβ1siRNA载体转染人腹膜间皮细胞,以半定量RTPCR和Western蛋白印迹方法检测转染后间皮细胞中TGFβ1表达水平的变化,以3HTdR掺入实验测定腹膜间皮细胞和人胃癌细胞株SGC7901之间的黏附变化。结果:电泳、DNA测序证实合成的siRNA基因序列正确并已准确克隆入pcPURβicassette载体。免疫组化染色结果显示腹膜间皮细胞角蛋白、波形蛋白表达阳性,而白细胞共同抗原(CD45)、第Ⅷ因子相关抗原阴性。与对照组比较,TGFβ1siRNA载体能显著下调TGFβ1mRNA(0.779±0.091vs0.503±0.064,P=0.013)和蛋白(77.67±5.69vs29.33±6.03,P=0.001)在腹膜间皮细胞中的表达,间皮细胞黏附胃癌细胞的能力减弱。结论:载体介导的RNAi技术可成功地干扰TGFβ1在腹膜间皮细胞中的表达。同时,降低了间皮细胞黏附肿瘤细胞的能力,有望减少胃癌腹膜转移的发生。     

Novel strategy of ovarian cancer implantation: Pre‐invasive growth of fibrin‐anchored cells with neovascularization

Although direct adhesion of cancer cells to the mesothelial cell layer is considered to be a key step for peritoneal invasion of ovarian cancer cell masses (OCM), we recently identified a different strategy for the peritoneal invasion of OCM. In 6 out of 20 cases of ovarian carcinoma, extraperitoneal growth of the OCM was observed along with the neovascularization of feeding vessels, which connect the intraperitoneal host stroma and extraperitoneal lesions through the intact mesothelial cell layer. As an early step, the OCMs anchor in the extraperitoneal fibrin networks and then induce the migration of CD34‐positive and vascular endothelial growth factor A (VEGF‐A)‐positive endothelial cells, constructing extraperitoneal vascular networks around the OCM. During the extraperitoneal growth of OCM, podoplanin‐positive and α smooth muscle actin (αSMA)‐positive cancer‐associated fibroblasts (CAF) appears. In more advanced lesions, the boundary line of mesothelial cells disappears around the insertion areas of feeding vessels and then extraperitoneal and intraperitoneal stroma are integrated, enabling the OCM to invade the host stroma, being associated with CAF. In addition, tissue factors (TF) are strongly detected around these peritoneal implantation sites and their levels in ascites were higher than that in blood. These findings demonstrate the presence of neovascularization around fibrin net‐anchored OCMs on the outer side of the intact peritoneal surface, suggesting a novel strategy for peritoneal invasion of ovarian cancer and TF‐targeted intraperitoneal anti‐cancer treatment. We observed and propose a novel strategy for peritoneal implantation of ovarian cancer. The strategy includes the preinvasive growth of fibrin‐anchored cancer cells along with neovascularization on the outer side of the intact peritoneal surface.     

Peritoneal mesothelial cell injury factors in rat cancerous ascites

To elucidate the mechanism of the peritoneal dissemination of cancer, the influence of cancerous ascites on peritoneal mesothelial cells was studied by scanning electron microscopy and light microscopy. We inoculated normal Donryu rats with AH100B ascites hepatoma cells and studied the influence of the supernatant from cancerous ascites on the normal rat peritoneal surface by i.p. injection. The mesothelial cells were damaged and exfoliated markedly, which is supposed to be a profitable condition for cancer cells to proliferate on the peritoneal surface. Therefore, the presence of mesothelial cell injury factors was noted. Subsequently, we divided the supernatant from rat cancerous ascites into four fractions by gel filtration and revealed the distribution of mesothelial cell injury factors by studying the influence of each fraction on the normal rat peritoneal surface. Although Fraction I (fibrin fraction) and Fraction II (IgG fraction) made no changes on the peritoneal surface, Fraction III (albumin fraction) and Fraction IV provoked damages on the mesothelial cells. We found that the mesothelial cell injury factors are present in the albumin fraction and in the fraction containing low-molecular-weight substances.     

Adhesion of human gastric and pancreatic cancer cells to peritoneal mesothelial cells is mediated by CD44 and beta(1) integrin

Peritoneal dissemination is a common cause of the recurrence of gastric or pancreatic cancer after patients have undergone surgery. The presence of peritoneal metastasis after surgery affects the prognosis of patients with gastric or pancreatic cancer. Very little is known about the biochemical processes involved in the initial attachment of cancer cells to peritoneal mesothelial cells. We conducted in vitro and in vivo studies to assess the role of adhesion molecules in this process, using 5 cell lines derived from human gastric and pancreatic cancers. NUGC-4 and SW1990 cells, which disseminate earlier than the other 3 types of cancer cells after inoculation into the abdominal cavity of nude mice, express large amounts of CD44H. We found that NUGC-4 and SW1990 cells adhere to monolayers of mesothelial cells more firmly than the other cell lines, as shown by adhesion assays performed at 4 degrees C. The adhesion of NUGC-4 and SW1990 cells to mesothelial cells was partially inhibited by antibodies against CD44H or the beta(1) subunit of integrin, and they almost completely blocked adhesion when these 2 antibodies were used in combination in vitro. These 2 antibodies also inhibited the peritoneal metastasis of NUGC-4 and SW1990 cells and prolonged their mean survival time in vivo. These findings suggest that CD44H and beta(1) integrin play important roles in the initial attachment of gastric and pancreatic cancer cells to mesothelial cells. Our results suggest that changes in the expression of CD44H and beta(1) integrin in cancer cells is associated with their ability to adhere to peritoneal mesothelial cells, and thus with the peritoneal metastatic ability of gastric and pancreatic cancer cells. Therefore, the expression of CD44H and beta(1) integrin in gastric and pancreatic cancers could be used as prognostic indicators of peritoneal metastasis. It is possible that a treatment strategy that interferes with the functions of CD44H or beta(1) integrin may result in decreased intra-abdominal spread of cancer.     

Adhesion molecules and TGF-β1 are involved in the peritoneal dissemination of NUGC-4 human gastric cancer cells

Peritoneal dissemination frequently occurs after surgery in patients with gastric cancer. The presence of peritoneal metastasis after surgery affects prognosis. Very little is known about the biochemical processes involved in the initial attachment of gastric cancer cells to peritoneal mesothelial cells. We conducted in vitro and in vivo studies to assess the role of adhesion molecules and TGF-β1 in this process, using 4 cell lines derived from human gastric cancers. NUGC-4 cells, which disseminate early after inoculation into the abdominal cavity of nude mice, predominantly express CD44H and β₁ integrin. We found that NUGC-4 cells adhered to monolayers of mesothelial cells more firmly than to other cell lines. Adhesion of NUGC-4 cells to mesothelial cells was partially inhibited by antibodies against CD44H or the β₁ subunit of integrin and was completely blocked by a combination of these 2 antibodies. Treatment with ligands for CD44H and β₁ integrin also inhibited adhesion. In the NUGC-4 cell culture medium, larger amounts of TGF-β₁ were detected in relation to the increase in cancer cells than in the other cell lines. TGF-β1 increased the expression of CD44H in NUGC-4 cells and in mesothelial cells and augmented adhesion and implantation of NUGC-4 cells to mesothelial cells accompanied by accumulation of extracellular matrix (ECM) components. Treatment with antibodies against both CD44H and β₁ integrin inhibited the dissemination of NUGC-4 cells in the peritoneal cavity of nude mice and prolonged their survival time. Our findings suggest that CD44H and integrins mediate the initial attachment of gastric cancer cells to mesothelial cells and that TGF-β1 participates in the promotion of the disease. Increased expression of CD44H and of the amount of ligands for CD44H and integrins induced by TGF-β1 promotes early development of peritoneal dissemination. Int. J. Cancer 70:612–618. © 1997 Wiley-Liss Inc     

Peritoneal dissemination is inhibited by treatment with antibodies against CD44H, beta(1) integrin, and carcinostatic agents in NUGC-4 human gastric cancer cells

Peritoneal dissemination frequently occurs after surgery in patients with gastric cancer. The presence of peritoneal metastasis after surgery affects the prognosis, therefore, a way must be found to effectively prevent the development of peritoneal dissemination. Very little is known about the biochemical processes involved in the initial attachment of gastric cancer cells to peritoneal mesothelial cells. We conducted in vitro and in vivo studies to assess the role of adhesion molecules and TGF-beta 1 in this process, using 4 gastric cancer cell lines. NUGC-4 cells, which disseminate early after inoculation into the abdominal cavity of nude mice, predominantly expressed CD44H and beta(1) integrin. We found that NUGC-4 cells adhered to monolayers of mesothelial cells more firmly than other cell lines. Adhesion of NUGC-4 cells to mesothelial cells was partially inhibited by antibodies against CD44H or the beta(1) subunit of integrin, and was completely blocked by a combination of these 2 antibodies. Treatment with ligands for CD44H and beta(1) integrin also inhibited this adhesion. In the NUGC-4 cell culture medium, larger amounts of transforming growth factor beta 1(TGF-beta 1) was detected in proportion to the increase in cancer cells than in the other cell lines. TGF-beta 1 increased the expression of CD44H in NUGC-4 cells and in mesothelial cells, and augmented the adhesion and implantation of NUGC-4 cells to mesothelial cells accompanied by accumulation of extracellular matrix (ECM) components. Carcinostatic agents decreased the expression of CD44H but increased the expression of E-cadherin in NUGC-4 cells. Treatment with carcinostatic agents and antibodies against CD44H and beta(1) integrin inhibited the dissemination of NUGC-4 cells in the peritoneal cavity of nude mice, and prolonged their survival time. These findings suggest that CD44H and integrins mediate in the initial attachment of gastric cancer cells to mesothelial cells, and TGF-beta 1 participates in the promotion of the disease. It is possible that a treatment strategy that interferes with CD44H or integrins function and increases the functions of E-cadherin immediately after surgery may result in the decreased intra-abdominal spread of gastric cancer.     

Use of E-cadherin and CD44 aids in the differentiation between reactive mesothelial cells and carcinoma cells in pelvic washings

BACKGROUND: The presence of malignant cells in peritoneal washings is an independent prognostic factor in the evaluation of gynecologic malignancies. The differentiation between reactive mesothelial cells and carcinoma cells can be a diagnostic challenge based on morphology alone. The expression of some cell adhesion molecules may be helpful in the differential diagnosis. METHODS: To evaluate the specificity of 2 transmembrane cell adhesion proteins (E-cadherin and CD44) in the differentiation of mesothelial cells from carcinoma cells in pelvic washings, formalin fixed, paraffin embedded cell blocks of pelvic washings from 19 cases of metastatic ovarian adenocarcinoma and 16 cases of benign peritoneal washings were immunostained with monoclonal antibodies to E-cadherin and CD44. The staining patterns were evaluated blindly by three observers. Positive staining was defined as uniform membranous staining for each marker. RESULTS: Fourteen benign peritoneal washings (87.5%) demonstrated immunoreactivity with anti-CD44. On the contrary, only four adenocarcinomas (21.1%) demonstrated anti-CD44 immunoreactivity. E-cadherin expression was identified in only 2 benign peritoneal washings (12.5%) whereas 16 adenocarcinomas (84.2%) strongly expressed E-cadherin. The differences in immunostaining for both CD44 and E-cadherin between benign and malignant peritoneal washings were statistically significant. The combination of positive staining for E-cadherin and negative staining for CD44 was 100% specific for metastatic adenocarcinoma, whereas a combination of negative staining for E-cadherin and positive staining for CD44 was 100% specific for reactive mesothelial cells. CONCLUSIONS: Both E-cadherin and CD44 reliably distinguish reactive mesothelial cells from adenocarcinoma. The combination of E-cadherin/CD44 is highly specific and is a useful diagnostic adjunct with which to distinguish benign reactive mesothelial cells from adenocarcinoma in pelvic washings.     

Mechanisms of the formation of the peritoneal dissemination in gastric cancer

To clarify the mechanisms of the formation of peritoneal dissemination, a new animal model by the i.p. inoculation of highly metastatic gastric cancer cell line MKN-45-P was developed. Peritoneal dissemination with bloody ascites was found in 100% of nude mice, injected 1x10(7) MKN-45-P cells in suspension into the peritoneal cavity. By a highly sensitive method for specific detection of metastasized human tumor cells in nude mice using polymerase chain reaction, a human beta-globin-related sequence in the DNA from various parts of the peritoneum was specifically amplified and detected by gel electrophoresis and by a specific oligonucleotide probe. Greater omentum showed a strong signal of the amplified fragments of human beta-globin gene from the 1st day and the signals gradually increased. The signals in the gonadal fat, mesentery and ovarium could be weakly detected on the Ist day, transiently decreased on the 3rd day, and then increased from the 7th day. In the diaphragm, and abdominal wall, signals could be detected from the 7th day. In contrast, small intestine and colon did not show any human beta-globin signals. In greater omentum and gonadal fat, cancer cells were selectively detected in the milky spots stained by activated carbon on the 3rd day. In the diaphragm, cancer cells adhered to the small pores termed stomata, and invaded into the subdiaphragmatic lymphatic lacunae connected with stomata. From the 3rd day, mesothelial cells of the abdominal cavity became round and separated, resulting in the exposure of the underlying connective tissue. MKN-45-P cells were found to adhere to the naked areas of the submesothelial connective tissue. From these results, we conclude that the major metastatic route of the peritoneum may be firstly through milky spots, secondly through the diaphragmatic stomata, and thirdly by the adhesion to the naked connective tissue exposed after shrinkage of the mesothelial cells. The third process may be related to the interaction between some adhesion molecules and their ligands.     

CD44H Plays an Important Role in Peritoneal Dissemination of Scirrhous Gastric Cancer Cells

The role of the adhesion molecule CD44H in the peritoneal adhesion and invasion of cancer cells was assessed using cell lines with low and high peritoneal seeding ability, OCUM-2M (2M) and OCUM-2MD3 (2MD3), respectively. The in vitro binding ability to peritoneal components (mesothelial cells, fibroricetin and type I collagen) and invasive ability of 2MD3 cells were higher than those of 2M cells. The expression level of CD44H on 2MD3 cells was higher than that on 2M cells as determined by western blot analysis and flow cytometry. The adhesiveness of 2MD3 cells to hyaluronic acid, which is expressed on the surfaces of mesothelial cells, was greater than that of 2M cells. The binding ability of 2MD3 cells to mesothelial cells was inhibited in the presence of anti-CD44H monoclonal antibody, but that of 2M cells was not. These results suggested that the 2MD3 cell binding to mesothelial cells is regulated by the CD44-hyaluronic acid dependent system. The in vitro binding to submesothelial components and the invasiveness of 2MD3 cells were also inhibited in the presence of anti-CD44H antibody. The in vivo inoculation of 2MD3 cells treated with an anti-CD44H antibody resulted in a significant prolongation of survival time as compared with control mice that were inoculated with 2MD3 cells alone. In conclusion, CD44H was associated with attachment not only to hyaluronic acid on mesothelial cells, but also to peritoneal stromal components. Thus, CD44H may play an important role in cancer cell binding and invasion in the peritoneal dissemination of scirrhous gastric cancer cells.