High Expression Of CD9 Research Articles

Bioinformatics investigation of the prognostic value and mechanistic role of CD9 in glioma

In recent years, CD9 has been extensively studied as a potential biomarker for cancer. However, the biological role of CD9 in gliomas remains unclear. This study investigates the function of CD9 in gliomas and its molecular mechanisms. Utilizing pan-cancer analysis with TCGA, CGGA, and GEO databases, differential expression of CD9 was observed in 11 tumor types within the TCGA cohort, and it was associated with patient survival rates. Analysis of the CGGA glioma database revealed that patients with high CD9 expression had lower survival rates. The area under the ROC curve (AUC) for GSE16011 was greater than 0.7, indicating a high discriminative ability. Through gene set enrichment analysis (GSEA), immune-related analysis, and CD9 mutation detection, CD9 was found to have the strongest correlation with neutrophil involvement (cor = 0.30, P < 0.05), and the high CD9 expression group exhibited higher rejection responses and TIDE scores, suggesting a lower likelihood of successful immunotherapy. The high CD9 expression group was more sensitive to 81 drugs, indicating potential therapeutic effects for gliomas. Furthermore, overexpression of CD9 in gliomas may be associated with gene mutations. Down-regulation or up-regulation of CD9 expression in the glioblastoma cell line LN229 showed that CD9 could positively regulate the migratory ability of LN229 cells. Further, several marker genes, such as VEGFR-2, TGF-β1, CASP1 and PI3K, were down regulated in CD9 knockdown cell lines and up regulated in CD9 overexpression cell lines, compared with control cell line. This study preliminarily explores the role of CD9 in gliomas and its prognostic value, providing new insights for personalized treatment strategies in glioma therapy.

How does bariatric surgery remodel adipose tissue?

This lecture delves into the pivotal role of adipose tissue in obesity and its response to weight loss, particularly via bariatric surgery. Adipose tissue, responsible for storing excess energy, undergoes significant changes during obesity, marked by inflammation and fibrosis. Bariatric surgery, serving as a model, allow the exploration of adipose tissue remodeling post-weight loss, inducing metabolic and fibro-inflammatory shifts. Despite successful weight loss, inflammation and fibrosis persist, as evidenced by changes in immune cells, altered cytokine profiles and the accumulation of extracellular matrix (ECM). Unfortunately, these lingering effects impair the normal adipose tissue function. In this context, adipose progenitors, an heterogenous resident population of mesenchymal stromal cells, display functions important to fibrosis development, capable of differentiating into myofibroblasts and contributing to ECM deposition. Particularly, a distinct subpopulation of adipose progenitors with high CD9 expression (CD9high) is associated with fibrosis and insulin resistance in human obesity. The persistence of fibrosis post-weight loss poses challenges, correlating with metabolic dysfunction despite improved glucose tolerance. A comprehensive understanding of the mechanisms driving adipose tissue remodeling and fibrosis post-weight loss is imperative for the development of effective treatments for obesity. The intricate interplay between adipose tissue, inflammation, and fibrosis underscores the necessity for further in-depth research to elucidate these mechanisms and formulate targeted therapies for obesity-related complications.

High expression of CD9 and Epidermal Growth Factor Receptor promotes the development of tongue cancer.

Tongue cancer is distinguished by aggressive behavior, a high risk of recurrence, lymph, and distant metastases. Hypoxia-Induced Factor 1 α functions as a CD9 transcription factor. CD9 is a transmembrane protein that may be found on the cell membrane. It can modulate the expression of the Epidermal Growth Factor Receptor (EGFR) pathway. ELISA was used to measure serum CD9, p-EGFR, and p-Akt levels in 70 tongue cancer patients and 35 healthy controls. RT-PCR was used to analyze the gene expression of the related genes. The gene as well as protein expression of CD9, EGFR/p-EGFR, and Akt/p-Akt was significantly higher in case subjects when compared with the controls. The expression of CD9 was higher in case subjects who were smokers/alcoholics when to control subjects who were smokers/alcoholics. Overexpression of CD9 due to hypoxic conditions leads to the activation of EGFR-signaling pathway resulting in cancer progression, resistance to chemotherapy. Hence, CD9 could be a potential target to suppress cancer progression.

Prognostic value and multifaceted roles of tetraspanin CD9 in cancer.

CD9 is a crucial regulator of cell adhesion in the immune system and plays important physiological roles in hematopoiesis, blood coagulation or viral and bacterial infections. It is involved in the transendothelial migration of leukocytes which might also be hijacked by cancer cells during their invasion and metastasis. CD9 is found at the cell surface and the membrane of exosomes affecting cancer progression and therapy resistance. High expression of CD9 is mostly associated with good patients outcome, with a few exceptions. Discordant findings have been reported for breast, ovarian, melanoma, pancreatic and esophageal cancer, which might be related to using different antibodies or inherent cancer heterogeneity. According to in vitro and in vivo studies, tetraspanin CD9 is not clearly associated with either tumor suppression or promotion. Further mechanistic experiments will elucidate the role of CD9 in particular cancer types and specific conditions.

Advanced 3D dynamic culture system with transforming growth factor-β3 enhances production of potent extracellular vesicles with modified protein cargoes via upregulation of TGF-β signaling

IntroductionMesenchymal stromal cells (MSCs) release extracellular vesicles (MSC-EVs) containing various cargoes. Although MSC-EVs show significant therapeutic effects, the low production of EVs in MSCs hinders MSC-EV-mediated therapeutic development. ObjectivesHere, we developed an advanced three-dimensional (a3D) dynamic culture technique with exogenous transforming growth factor beta-3 (TGF-β3) treatment (T-a3D) to produce potent MSC-EVs. MethodsOur system enabled preparation of a highly concentrated EV-containing medium for efficient EV isolation and purification with higher yield and efficacy. ResultsMSC spheroids in T-a3D system (T-a3D spheroids) showed high expression of CD9 and TGF-β3, which was dependent on TGF-β signaling. Treatment with EVs produced under T-a3D conditions (T-a3D-EVs) led to significantly improved migration of dermal fibroblasts and wound closure in an excisional wound model. The relative total efficacy (relative yield of single-batch EVs (10–11-fold) × relative regeneration effect of EVs (2–3-fold)) of T-a3D-EVs was approximately up to 33-fold higher than that of 2D-EVs. Importantly the quantitative proteomic analyses of the T-a3D spheroids and T-a3D-EVs supported the improved EV production as well as the therapeutic potency of T-a3D-EVs. ConclusionTGF-β signalling differentially regulated by fluid shear stress produced in our system and exogenous TGF-β3 addition was confirmed to play an important role in the enhanced production of EVs with modified protein cargoes. We suggest that the T-a3D system leads to the efficient production of MSC-EVs with high potential in therapies and clinical development.

Naturally Equipped Urinary Exosomes Coated Poly (2-ethyl-2-oxazoline)-Poly (D, L-lactide) Nanocarriers for the Pre-Clinical Translation of Breast Cancer.

Recently, biomimetic nanoparticles for tumor−targeted therapy have attracted intensifying interest. Although exosomes are an excellent biomimetic material, numerous challenges are still hindering its clinical applications, such as low yield, insufficient targeting efficiency, and high cost. In this work, urinary exosomes (UEs) with high expression of CD9 and CD47 were extracted from breast cancer patients by a non−invasive method. Here, a nanotechnology approach is reported for tumor homologous targeting via CD9 and phagocytosis escape via CD47 through UE−coated poly (2−ethyl−2−oxazoline)−poly (D, L−lactide) (PEOz−PLA) nanoparticles (UEPP NPs). The cytotoxic agent doxorubicin (DOX)−loaded UEPP (UEPP−D) NPs with an initial particle size of 61.5 nm showed a burst release under acidic condition mimicking the tumor microenvironment. In vitro experiments revealed that UEPP−D NPs exhibited significantly improved cellular uptake, cytotoxicity, and apoptosis in MCF−7 cell lines as compared to DOX−loaded PEOz−PLA nanoparticles (PP−D NPs) and free DOX. More importantly, anti−phagocytosis and pharmacokinetic studies confirmed that UEPP−D NPs had superior immune escape ability and significantly prolonged the drug’s bloodstream circulation in vivo. Finally, UEPP−D NPs showed a markedly higher antitumor efficacy and lower side−toxicity in MCF−7 tumor bearing nude mice model. Thus, this versatile nano−system with immune escape, homologous targeting, and rapid response release characteristics could be a promising tool for breast cancer treatment.

Abstract 5219: Effect of extracellular vesicles from gastric cancer cells on the morphologic and genetic changes of peritoneal mesothelial cells

Abstract Background: Gastric cancer is a major cause of cancer death, particularly on the basis of peritoneal metastasis. Human scirrhous gastric carcinoma (SGC), diffusely infiltrating carcinoma, or Borrman type 4 also known as linitis plastica-type carcinoma is characterized by rapid cancer cell infiltration and proliferation accompanied by extensive stromal fibrosis. SGC account for about 10% of all gastric carcinomas, and carry an extremely worse prognosis than other types of gastric carcinoma, reflecting their frequent peritoneal metastasis. We previously reported that SGC cells (“seed”) might change the peritoneum to favorable environment, so-called pre-metastatic niche (“soil”), (Cancer 77:1668-75, 1996). Recently, it has been clarified that extracellular vesicles (EVs) play an important role for cell-cell interactions. In this study, we investigated the effect of EVs from SGC cells on the pre-metastatic niche formation of the peritoneum. Methods: A SGC cell line, OCUM-2MD3, OCUM-12, KATO-III, gastric cancer cell line, MKN74, MKN45, and peritoneal mesothelial cells (PM cells) were used. PKH26-labeled EVs from OCUM-2MD3 cells were intravenously injected into nude mice, and the distribution of EVs was examined by a fluorescence microscope. The morphology of PM cells was investigated in the addiction of EVs from various gastric cancer cell lines using a phase-contrast microscope. And gene expression was examined by RT-PCR in the presence or absence of EVs from OCUM-2MD3. Clinical significance of EVs markers CD9 and CD63 was immunohistochemically evaluated using 63 human gastric cancer specimens. Results: PKH26-labeled EVs were frequently found in the peritoneum, stomach and liver, but rare in lung and brain of mice. Peritoneal mesothelial cells uptake EVs of gastric cancer cells and change morphology from cobblestone shape to spindle shape in vitro. mRNA expression level of MMPs and integrins in PM cells was increased following the addiction of EVs, in compared with the control. The high expression of CD9 and CD63 was significantly correlated with distant metastasis. Conclusion: EVs from gastric cancer cells might induce a pre-metastatic niche at peritoneum by the morphologic and genetic changes of mesothelial cells. Citation Format: Tomohisa Okuno, Masakazu Yashiro, Shingo Togano, Kenji Kuroda, Yuichiro Miki, Hiroaki Kasashima, Kosei Hirakawa, Masaichi Ohira. Effect of extracellular vesicles from gastric cancer cells on the morphologic and genetic changes of peritoneal mesothelial cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5219.

A PDGFRα-Mediated Switch toward CD9high Adipocyte Progenitors Controls Obesity-Induced Adipose Tissue Fibrosis

Obesity-induced white adipose tissue (WAT) fibrosis is believed to accelerate WAT dysfunction. However, the cellular origin of WAT fibrosis remains unclear. Here, we show that adipocyte platelet-derived growth factor receptor-α-positive (PDGFRα+) progenitors adopt a fibrogenic phenotype in obese mice prone to visceral WAT fibrosis. More specifically, a subset of PDGFRα+ cells with high CD9 expression (CD9high) originates pro-fibrotic cells whereas their CD9low counterparts, committed to adipogenesis, are almost completely lost in the fibrotic WAT. PDGFRα pathway activation promotes a phenotypic shift toward PDGFRα+CD9high fibrogenic cells, driving pathological remodeling and altering WAT function in obesity. These findings translated to human obesity as the frequency of CD9high progenitors in omental WAT (oWAT) correlates with oWAT fibrosis level, insulin-resistance severity, and type 2 diabetes. Collectively, our data demonstrate that in addition to representing a WAT adipogenic niche, different PDGFRα+ cell subsets modulate obesity-induced WAT fibrogenesis and are associated with loss of metabolic fitness.

Expression of CD9 and CD82 in clear cell renal cell carcinoma and its clinical significance

CD9 and CD82, members of the tetraspanin family, act as metastasis suppressors in many human malignant tumors, but the role of these molecules is not well known in clear cell renal cell carcinoma (CCRCC). This study was designed to evaluate the immunohistochemical expression of CD9 and CD82 in 644 cases of CCRCC and to determine the clinicopathologic and prognostic significance of their expression. The percentage of positive tumor cells was evaluated, and the expression was classified into 2 categories: low expression (less than 10% positive cells) or high expression (more than 10% positive cells) for CD9 expression and negative (no positive cells) or positive for CD82 expression. CD9 high expression was found in 303 (47.0%) patients, and CD82 positivity was found in 98 (15.2%) patients. High expression of CD9 was statistically associated with older patients (p=0.003). The cases showing positive immunoreactivity for CD82 exhibited a high stage (p<0.001) and high nuclear grade (p<0.001). The overall, cancer-specific and progression-free survival rates were significantly higher in patients with a CD82-negative profile compared to patients with a CD82-positive profile (p<0.001). Although the biological function of CD82 in CCRCC remains unclear, the CCRCC patients with CD82 positive expression show poor prognosis.

Osteopontin Promotes the Invasive Growth of Melanoma Cells by Activating Integrin αvβ3 and Down-Regulating Tetraspanin CD9

Overexpression of osteopontin (OPN) is strongly associated with the invasiveness/metastasis of many cancers, including melanomas. However, the molecular mechanisms of OPN in these processes remain poorly understood. We found that forced expression of OPN in early vertical-growth-phase melanoma cells dramatically increased their migration/invasion and growth/survival in a three-dimensional collagen I gel. Neutralizing antibodies to OPN, integrin β1, and integrin αvβ3, but not to CD44, negated the effects of OPN. Conversely, knocking down OPN in metastatic melanoma cells abrogated the invasive growth. OPN overexpression activated and OPN knockdown inactivated αvβ3 and αvβ5 integrins, negligibly affecting their expression. We further found OPN expression to inversely correlate with tetraspanin CD9 expression. Early-stage melanoma cells displayed low OPN and high CD9 expression, and conversely, metastatic cells displayed high OPN and low CD9 expression. Overexpression of OPN in vertical-growth-phase melanoma cells induced down-regulation of CD9, and knockdown of OPN in metastatic melanoma cells up-regulated CD9. Reversion of these CD9 changes abolished the effects of OPN. Furthermore, knockdown of CD9 in early-stage melanoma cells stimulated their invasive capacity in three-dimensional collagen. Similarly, microarray analyses of benign nevi and primary melanomas from different stages revealed an inverse correlation between OPN and CD9. These data suggest that OPN promotes melanoma cell invasion by activating integrin αvβ3 and down-regulating CD9, a putative metastasis suppressor.

Expression of cell surface CD9 in fertile and infertile women

CD9 is a cell surface protein that plays a crucial role in mouse sperm-oocyte fusion. We compared the CD9 expression levels on human platelets in women with unexplained infertility vs. age, weight, and race-matched fertile women. In in vitro fertilization (IVF) patients, we also compared platelet CD9 levels to fertilization rates. Prospective, observational, cohort study of women with unexplained infertility as compared to fertile women. Twenty women with unexplained infertility ages 26–43 were recruited from an academic fertility clinic. Each study subject demonstrated positive ovulatory function, normal ovarian reserve, patent fallopian tubes, and a normal semen analysis from the male partner. Twenty women with demonstrated fertility were recruited as control subjects. Each control subject had at least one liveborn offspring and no history of infertility or use of fertility drugs. Subjects were matched one to one to a control within 2 years of age, 1.5 kg/m2 of BMI, and by race. From each study subject and control, platelet CD9 expression was evaluated by flow cytometry. Fertilization rates of the study subjects who underwent IVF were calculated and compared to corresponding CD9 levels. Infertile patients (mean 113.2 MFI ± 38) demonstrated higher CD9 levels than the fertile controls (mean 99.5 MFI ± 25) though this was not statistically significant (p = 0.120). Using linear regression analysis, there was an inverse relationship between CD9 levels and fertilization rates of the 12 IVF patients (r = -0.6547, p = 0.0209). CD9 levels of infertile patients were increased over that of fertile patients though not statistically significant. Studies by Le Naour et al. with female CD9 knockout mice showed decreased fertility rates. Contrary to this, our study, using platelets as a cell surrogate for oocytes, revealed higher CD9 levels in infertile patients. Furthermore, the IVF patients with higher CD9 levels had decreased fertilization rates. Our data suggest that the high CD9 expression may have a negative effect on fertility via competition, as may decreased levels, ultimately affecting the efficiency of sperm-egg fusion. If so, we would expect infertile patients with abnormal CD9 levels to have improved fertilization rates by eliminating sperm-egg fusion via intracytoplasmic sperm injection (ICSI). Our study suggests that CD9 may play a crucial role in unexplained human infertility.

Tetraspanin CD9 Is Associated With Very Late–Acting Integrins in Human Vascular Smooth Muscle Cells and Modulates Collagen Matrix Reorganization

CD9, a member of the tetraspanin family, and very late-acting (VLA) integrins are known to associate and form functional units on the surface of several cell types. We studied the changes in expression of CD9 and beta1-integrins (CD29, VLA) in human vascular smooth muscle cells (VSMCs) under in vitro culture conditions mimicking proliferative vascular diseases. We also investigated possible interactions between CD9 and VLA integrins in VSMCs. We found that CD9 is highly expressed in VSMCs and is subject to modulation, depending on the proliferative/contractile state of the cells. In the contractile phenotype, the levels of CD9, CD81, another tetraspanin, and CD29 are approximately 50% of those found in the proliferative phenotype. Coimmunoprecipitation experiments showed physical association between CD9 and CD29. CD9 was mainly associated with alpha2 and alpha3-integrins (CD49b and c) and also with alpha5-integrin to a weaker extent. Functionally, the addition of anti-CD9 monoclonal antibodies (MoAbs) doubled the extent of collagen gel contraction mediated by VSMCs, a model for the reorganization of the extracellular collagen matrix occurring in the vessel wall. Anti-CD29 MoAbs inhibited gel contraction, but anti-CD9 MoAbs counteracted this inhibitory effect of anti-CD29 MoAbs. Transfection of human CD9 into Chinese hamster ovary cells more than doubled the extent of Chinese hamster ovary cell-mediated collagen gel contraction (130% stimulation), confirming a role for CD9 in extracellular matrix reorganization. Thus, CD9 seems to be involved in the modulation of VLA integrin-mediated collagen matrix reorganization by VSMCs. These findings suggest that high CD9 expression is associated with a proliferative state of VSMCs. The role of CD9 could be to modulate the function of VLA integrins on the surface of VSMCs.

Expression of transmembrane 4 superfamily member, CD9, is related to improved progression-free survival in patients with diffuse non-Hodgkin's lymphoma.

Decreased expression of the transmembrane 4 superfamily member, CD9, is associated with poor prognosis in patients with breast or non-small cell lung cancer. The expression of CD9 in lymphoma was examined in this study. Fifty-one sections with diffuse lymphomas were examined. Thirty-seven had low expression and 14 high expression of CD9. At 5 years the progression-free survival rates were 83.3+/-10.8% and 32.8+/-9.2% (p=0.018), and the actual survival were 83.3+/-10.8% and 56.8+/-8.9% (p=0.256) for those with high and low CD9 expression respectively. Decreased expression of CD9 appears to be a prognostic factor for poor survival in patients with diffuse lymphomas.