Platelet-derived Growth factor-A Expression Research Articles

Increased Expression of PDGFA Is Associated With Poor Prognosis and Immune Infiltration in Head and Neck Squamous Cell Carcinoma.

Platelet-derived growth factor A (PDGFA) has been shown to be upregulated in several tumors, contributing to their malignant phenotypes. However, its expression and function in head and neck squamous cell carcinoma (HNSC) are not clearly understood. Thus, we aimed to evaluate this issue using bioinformatic analyses and primary experimental validation. The expression of PDGFA was analyzed using popular bio-databases and further validated by RT-PCR and immunohistochemical staining. Survival analyses were then performed. The association between PDGFA expression levels and immune cell infiltration in the immune microenvironment was assessed. PDGFA has been found to be significantly upregulated in a variety of cancers, including HNSC, and increased PDGFA expression may be an independent prognostic factor associated with immune cell infiltration in HNSC. Overexpression of PDGFA in HNSC is significantly associated with poor prognosis and immune cell infiltration in the tumor microenvironment (TME). PDGFA has potential as a molecular indicator for diagnosis, prognosis, and immune processes in HNSC.

High expression of PDGFA predicts poor prognosis of esophageal squamous cell carcinoma.

Platelet-derived growth factor A (PDGFA), the most known member of PDGF family, plays a crucial role in occurrence and progression of different tumors. However, PDGFA expression and its clinical significance in esophageal squamous cell carcinoma (ESCC) are not clear. The present study aimed to assess the expression and prognostic value of PDGFA in ESCC.The Gene Expression Omnibus databases (GSE53625, GSE23400, and GSE67269) and fresh clinical samples were employed for detecting PDGFA messenger RNA expression in ESCC. The associations of PDGFA expression with clinicopathological characteristics were evaluated by chi-square test. Kaplan–Meier analysis and Cox proportional hazard regression model were performed to determine the prognostic value of PDGFA in ESCC patients. PDGFA-related signaling pathways were defined by gene set enrichment analysis based on Gene Expression Omnibus databases.The PDGFA messenger RNA expression was upregulated in ESCC tissues compared with paired adjacent noncancerous tissues (P < .05) and was positively correlated with T stage (P < .05). Kaplan–Meier survival analysis suggested that ESCC patients with high PDGFA expression were associated with poorer overall survival compared to those with low PDGFA expression (P < .05), especially in advanced T stage (P < .05). Cox analyses showed that high expression of PDGFA was an independent predictor for poor prognosis in ESCC patients. Gene set enrichment analysis identified 3 signaling pathways (extracellular matrix receptor interaction, focal adhesion, and glycosaminoglycan biosynthesis chondroitin sulfate) that were enriched in PDGFA high expression phenotype (all P < .01).PDGFA may serve as an oncogene in ESCC and represent an independent molecular biomarker for prognosis of ESCC patients.

FOXE1 inhibits cell proliferation, migration and invasion of papillary thyroid cancer by regulating PDGFA

PurposeForkhead box E1 (FOXE1) plays an important role in the development, proliferation and differentiation of thyroid cells. However, the biological functions of FOXE1 in papillary thyroid cancer (PTC) remain unclear. Materials and methodsIn this study, the level of FOXE1 expression was examined in human PTC tissues and cells. Then, the high expression of FOXE1 was specifically silenced by RNA interference in vitro. Subsequently, FOXE1-shRNA was transfected into PTC cells (TPC-1 and K1). The effects on cell proliferation, migration and invasion were evaluated. In addition, FOXE1 targets were screened by cDNA microarray assays. The correlation between the expression of target gene platelet-derived growth factor A (PDGFA) and clinicopathological features of PTC patients was analysed. ResultsFOXE1 is highly expressed in PTC tissues and PTC cell lines. The silencing of FOXE1 significantly promotes PTC cell proliferation, migration and invasion in vitro. The cDNA microarray analyses show that PDGFA is a critical downstream target gene of FOXE1 in PTC cells. It was also observed that PDGFA is negatively regulated by FOXE1 in PTC. The clinical data indicate that the low expression level of PDGFA is correlated with the small size of PTC. ConclusionCollectively, the results indicate for the first time that high expression of FOXE1 may function as a tumour suppressor in the early stage of PTC and restrain the proliferation, migration and invasion of PTC by negatively regulating PDGFA expression. Thus, FOXE1 could serve as a prognostic biomarker for PTC.

Induction of nuclear protein-1 by thyroid hormone enhances platelet-derived growth factor A mediated angiogenesis in liver cancer.

Background & Aims: Hepatocellular carcinoma (HCC) is among the leading causes of cancer deaths worldwide. Many studies indicate that disruption of cellular thyroid hormone signaling promotes HCC progression. However, the mechanisms underlying the regulation of genes downstream of thyroid hormone actions in HCC have remained elusive. In the current study, we identified NUPR1 (nuclear protein-1), a stress-induced protein that overexpresses in various neoplasia, is upregulated by triiodothyronine/thyroid hormone receptor (T3/TR) signaling and aimed to elucidate its role in angiogenesis in cancer progression.Methods: Quantitative reverse transcription-PCR, luciferase promoter and chromatin immunoprecipitation assays were performed to identify the NUPR1 regulatory mechanism by T3/TR. In vitro and In vivo vascular formations were performed to detect the angiogenic function of NUPR1. Human angiogenesis arrays were performed to identify the downstream angiogenic pathway. The sorafenib resistant ability of TR/NUPR1 was further examined in vitro and in vivo. Clinical relevance of TR, NUPR1 and platelet-derived growth factor A (PDGFA) were investigate in HCC samples using qRT-PCR and western blot.Results: Our experiments disclosed positive regulation of NUPR1 expression by T3/TR through direct binding to the -2066 to -1910 region of the NUPR1 promoter. Elevated NUPR1 and TR expression link to poor survival in clinical HCC specimens. An analysis of clinicopathological parameters showed that expression of NUPR1 is associated with vascular invasion and pathology stage. Functional studies revealed that NUPR1 induced endothelial cell angiogenesis in vitro and in vivo. Using a human angiogenesis array, we identified PDGFA as a target of NUPR1 in the downstream angiogenic pathway. NUPR1 induced transcription of PDGFA through direct binding to the corresponding promoter region, and inhibition of the PDGFA signaling pathway impaired angiogenesis in human umbilical vein endothelial cells (HUVECs). Notably, the angiogenic effects of NUPR1/PDGFA were mediated by the MEK/ERK signaling pathway. TR/NUPR1 expression increased cell viability and resistance to sorafenib treatment. Moreover NUPR1 expression was positively correlated with TRα, TRβ, and PDGFA expression.Conclusions: We propose that the T3/TR/NUPR1/PDGFA/MEK/ERK axis has a vital role in hepatocarcinogenesis and suggest NUPR1 as a potential therapeutic target in HCC.

Autocrine DUSP28 signaling mediates pancreatic cancer malignancy via regulation of PDGF-A

Pancreatic cancer remains one of the most deadly cancers with a grave prognosis. Despite continuous efforts to improve remedial values, limited progress has been made. We have reported that dual specificity phosphatase 28 (DUSP28) has a critical role of chemo-resistance and migration in pancreatic cancers. However, its mechanism remains unclear. Here, we further clarify the function of DUSP28 in pancreatic cancers. Analysis using a public microarray database and in vitro assay indicated a critical role of platelet derived growth factor A (PDGF-A) in pancreatic cancer malignancy. PDGF-A was positively regulated by DUSP28 expression at the mRNA and protein levels. Enhanced DUSP28 sensitized pancreatic cancer cells to exogenous PDGF-A treatment in migration, invasion, and proliferation. Transfection with siRNA targeting DUSP28 blunted the influence of administered PDGF-A by inhibition of phosphorylation of FAK, ERK1/2, and p38 signalling pathways. In addition, DUSP28 and PDGF-A formed an acquired autonomous autocrine-signaling pathway. Furthermore, targeting DUSP28 inhibited the tumor growth and migratory features through the blockade of PDGF-A expression and intracellular signaling in vivo. Our results establish novel insight into DUSP28 and PDGF-A related autonomous signaling pathway in pancreatic cancer.

Prostate field cancerization: deregulated expression of macrophage inhibitory cytokine 1 (MIC-1) and platelet derived growth factor A (PDGF-A) in tumor adjacent tissue.

Prostate field cancerization denotes molecular alterations in histologically normal tissues adjacent to tumors. Such alterations include deregulated protein expression, as we have previously shown for the key transcription factor early growth response 1 (EGR-1) and the lipogenic enzyme fatty acid synthase (FAS). Here we add the two secreted factors macrophage inhibitory cytokine 1 (MIC-1) and platelet derived growth factor A (PDGF-A) to the growing list of protein markers of prostate field cancerization. Expression of MIC-1 and PDGF-A was measured quantitatively by immunofluorescence and comprehensively analyzed using two methods of signal capture and several groupings of data generated in human cancerous (n = 25), histologically normal adjacent (n = 22), and disease-free (n = 6) prostate tissues. A total of 208 digitized images were analyzed. MIC-1 and PDGF-A expression in tumor tissues were elevated 7.1x to 23.4x and 1.7x to 3.7x compared to disease-free tissues, respectively (p<0.0001 to p = 0.08 and p<0.01 to p = 0.23, respectively). In support of field cancerization, MIC-1 and PDGF-A expression in adjacent tissues were elevated 7.4x to 38.4x and 1.4x to 2.7x, respectively (p<0.0001 to p<0.05 and p<0.05 to p = 0.51, respectively). Also, MIC-1 and PDGF-A expression were similar in tumor and adjacent tissues (0.3x to 1.0x; p<0.001 to p = 0.98 for MIC-1; 0.9x to 2.6x; p<0.01 to p = 1.00 for PDGF-A). All analyses indicated a high level of inter- and intra-tissue heterogeneity across all types of tissues (mean coefficient of variation of 86.0%). Our data shows that MIC-1 and PDGF-A expression is elevated in both prostate tumors and structurally intact adjacent tissues when compared to disease-free specimens, defining field cancerization. These secreted factors could promote tumorigenesis in histologically normal tissues and lead to tumor multifocality. Among several clinical applications, they could also be exploited as indicators of disease in false negative biopsies, identify areas of repeat biopsy, and add molecular information to surgical margins.

Dependence of fibroblast infiltration in tumor stroma on type IV collagen-initiated integrin signal through induction of platelet-derived growth factor

Cancer-associated fibroblasts play a crucial role in accelerating tumor progression, but there is a knowledge gap regarding the chemotactic signal activated in a tumor microenvironment. In this study, the expression of type IV collagen was knocked down using a lentiviral-mediated short hairpin RNA strategy. Although there was no obvious effect on cell growth in vitro, silencing the Col4-α1 gene decreased the tumorigenicity of B16F10 in C57BL/6 mice, which was accompanied by a reduction in the infiltration of alpha-smooth muscle actin-positive (α-SMA+) fibroblasts. Silencing the Col4-α1 gene or disrupting integrin engagement by blocking the antibody reduced the expression of platelet-derived growth factor A (PDGF-A), a potent chemotactic factor for fibroblasts. Furthermore, ectopic expression of the autoclustering integrin mutant significantly stimulated PDGF-A expression in murine B16F10 and human U118MG and Huh7 cells. PDGF-A-specific sh-RNA and neutralizing anti-PDGF-A antibody effectively inhibited the transwell migration of fibroblasts. Adding recombinant PDGF-A back to shCol cell-conditioned media restored the fibroblast-attraction ability indicating that PDGF-A is a major chemotactic factor for fibroblasts in the current study model. The integrin-associated PDGF-A production correlated with the activation of Src and ERK. High type IV collagen staining intensity colocalized with elevated PDGF-A expression was observed in tumor tissues obtained from hepatoma and glioma patients. The integrin signal pathway was activated by collagen engagement through Src and ERK, leading to enhanced PDGF-A production, which serves as a key regulator of fibroblast recruitment.

Correction: Characterization of Platelet-Derived Growth Factor-A Expression in Mouse Tissues Using a lacZ Knock-In Approach

Correction: Characterization of Platelet-Derived Growth Factor-A Expression in Mouse Tissues Using a lacZ Knock-In Approach

Effect of unfocused extracorporeal shock wave therapy on growth factor gene expression in wounds and intact skin of horses

To compare the effect of extracorporeal shock wave therapy (ESWT) on expression of fibroblast growth factor-7 (FGF-7), transforming growth factor-β1 (TGF-β1), insulin-like growth factor-1 (IGF-1), platelet-derived growth factor-A (PDGF), and vascular endothelial growth factor-A (VEGF) in skin with surgically created skin wounds and intact skin in horses. 14 healthy horses. 8 horses were treated with ESWT at 6 locations along the neck at 36, 24, 12, 6, 2, or 1 hour prior to collection of full-thickness biopsy specimens from each location; a control specimen was collected from a sham-treated location. In 6 horses, 5 full-thickness wounds were created in each forelimb. Wounds in 1 forelimb/horse received ESWT immediately after creation and subsequently on days 7, 14, and 21; wounds in the contralateral forelimb remained untreated. Biopsy specimens were collected from 1 wound on each forelimb on days 7, 14, 21, 28, and 35. Expression levels of FGF-7, TGF-β1, IGF-1, PDGF, and VEGF were assessed in tissue samples from the horses' necks and forelimbs. In surgically created wounds, ESWT treatment was associated with reduced TGF-β1 expression, compared with expression in control wounds, during the entire study period. At 28 days following wound creation, IGF-1 expression was significantly increased for treated and untreated wounds, compared with findings on days 7, 14, 21, and 35. There was no significant effect of treatment on FGF-7, TGF-β1, IGF-1, PDGF, or VEGF expression in intact skin. Intervention with ESWT to suppress TGF-β1 may decrease granulation tissue production, resulting in improved wound healing on the distal portion of horses' limbs.

Gene and protein expression of cartilage canal and osteochondral junction chondrocytes and full-thickness cartilage in early equine osteochondrosis

The objective of this study was to investigate the expression of several regulatory factors associated with cartilage maturation in horses with early osteochondrosis (OC) compared to normal controls. The hypothesis was that expression levels of Indian hedgehog (Ihh), parathyroid hormone-related peptide (PTH-rP), vascular endothelial growth factor (VEGF), platelet-derived growth factor-A (PDGF-A), and matrix metalloproteinase-13 and -3 (MMP-13, -3) would be increased in OC. Articular cartilage and osteochondral samples were collected from the femoropatellar joints from seven OC and eight normal young (1-6 months) horses after euthanasia and snap frozen or suspended in 4% paraformaldehyde. Laser capture microdissection was used to capture cells surrounding cartilage canals and the osteochondral junction. Total RNA was isolated from whole cartilage and laser-captured cells. Equine-specific Ihh, PTH-rP, VEGF, PDGF-A, MMP-13, and MMP-3 mRNA expression levels were evaluated by real-time (RT)-PCR. Spatial tissue protein expression was determined by immunohistochemistry. In laser-captured samples, there was significantly increased MMP-13 and PDGF-A gene expression in chondrocytes adjacent to cartilage canals and increased PDGF-A gene expression in osteochondral junction chondrocytes of OC-affected foals. In full-thickness cartilage samples, there was significantly increased Ihh, MMP-3, and MMP-13 gene expression in OC samples, while PTH-rP protein expression was significantly higher along the osteochondral junction. The results suggest that pathways involving cartilage maturation and ossification are altered in early OC and may be associated with disease pathogenesis.

MUC1 regulates PDGFA expression during pancreatic cancer progression

Pancreatic Ductal Adenocarcinoma (PDA) has one of the worst prognoses of all cancers. Mucin 1 (MUC1), a transmembrane mucin glycoprotein, is a key modulator of several signaling pathways that affect oncogenesis, motility, and metastasis. Its expression is known to be associated with poor prognosis in patients. However, the precise mechanism remains elusive. We report a novel association of MUC1 with Platelet-Derived Growth Factor-A (PDGFA). PDGFA is one of the many drivers of tumor growth, angiogenesis, and metastasis in PDA. Using mouse PDA models as well as human samples, we show clear evidence that MUC1 regulates the expression and secretion of PDGFA. This, in turn, influences proliferation and invasion of pancreatic cancer cells leading to higher tumor burden in vivo. In addition, we reveal that MUC1 over expressing cells are heavily dependent on PDGFA both for proliferation and invasion while MUC1-null cells are not. Moreover, PDGFA and MUC1 are critical for translocation of βcatenin to the nucleus for oncogenesis to ensue. Finally, we elucidate the underlying mechanism by which MUC1 regulates PDGFA expression and secretion in pancreatic cancer cells. We show that MUC1 associates with Hif1-α, a known transcription factor involved in controlling PDGFA expression. Furthermore, MUC1 facilitates Hif1-α translocation to the nucleus. In summary, we have demonstrated that MUC1-induced invasion and proliferation occurs via increased exogenous production of PDGFA. Thus, impeding MUC1 regulation of PDGFA signaling may be therapeutically beneficial for patients with PDA.

FGF-2, TGFβ-1, PDGF-A and respective receptors expression in pleomorphic adenoma myoepithelial cells: an in vivo and in vitro study

Myoepithelial cells have an important role in salivary gland tumor development, contributing to a low grade of aggressiveness of these tumors. Normal myoepithelial cells are known by their suppressor function presenting increased expression of extracellular matrix genes and protease inhibitors. The importance of stromal cells and growth factors during tumor initiation and progression has been highlighted by recent literature. Many tumors result from the alteration of paracrine growth factors pathways. Growth factors mediate a wide variety of biological processes such as development, tissue repair and tumorigenesis, and also contribute to cellular proliferation and transformation in neoplastic cells.ObjectivesThis study evaluated the expression of fibroblast growth factor-2 (FGF-2), transforming growth factor β-1 (TGFβ-1), platelet-derived growth factor-A (PDGF-A) and their respective receptors (FGFR-1, FGFR-2, TGFβR-II and PDGFR-α) in myoepithelial cells from pleomorphic adenomas (PA) by in vivo and in vitro experiments.Material and MethodsSerial sections were obtained from paraffin-embedded PA samples obtained from the school’s files. Myoepithelial cells were obtained from explants of PA tumors provided by surgery from different donors. Immunohistochemistry, cell culture and immunofluorescence assays were used to evaluate growth factor expression.ResultsThe present findings demonstrated that myoepithelial cells from PA were mainly positive to FGF-2 and FGFR-1 by immunohistochemistry and immunofluorescence. PDGF-A and PDGFR-α had moderate expression by immunohistochemistry and presented punctated deposits throughout cytoplasm of myoepithelial cells. FGFR-2, TGFβ-1 and TGFβR-II were negative in all samples.ConclusionsThese data suggested that FGF-2 compared to the other studied growth factors has an important role in PA benign myoepithelial cells, probably contributing to proliferation of these cells through the FGFR-1.

Expression of platelet-derived growth factor and its receptor at human and mouse neuromuscular junctions

Objective To investigate the immunoreactivity of platelet-derived growth factor-A (PDGF-A) and its receptor at human and mouse neuromuscular junctions and to explore their regulatory effects on neuromuscular junctions. Methods Specific polyclonal antibodies were used to detect PDGF-A and PDGF a-receptor expression. Double immunohistochemistry for platelet-derived growth factor and the acetylcholine receptor was performed on normal human muscle biopsy specimens. Double fluorescence labeling was applied to detect immunoreactivity for PDGF-A, its receptor and acetylcholine receptors. Results PDGF-A and its receptor was closely co-localized with acetylcholine receptors at human and mouse neuromuscular junctions. Conclusion PDGF-A and its receptor concentrated at human and mouse neuromuscular junctions. PDGF might be involved in the interaction between the presynaptic and postsynaptic components, PDGF-A and its receptor might play regulatory role in signaling at neuromuscular junctions in normal muscle. Key words: Platelet-derived growth factor; Receptor; Neuromuscular junction

Characterization of the G-quadruplexes in the duplex nuclease hypersensitive element of the PDGF-A promoter and modulation of PDGF-A promoter activity by TMPyP4

The proximal 5′-flanking region of the human platelet-derived growth factor A (PDGF-A) promoter contains one nuclease hypersensitive element (NHE) that is critical for PDGF-A gene transcription. On the basis of circular dichroism (CD) and electrophoretic mobility shift assay (EMSA), we have shown that the guanine-rich (G-rich) strand of the DNA in this region can form stable intramolecular parallel G-quadruplexes under physiological conditions. A Taq polymerase stop assay has shown that the G-rich strand of the NHE can form two major G-quadruplex structures, which are in dynamic equilibrium and differentially stabilized by three G-quadruplex-interactive drugs. One major parallel G-quadruplex structure of the G-rich strand DNA of NHE was identified by CD and dimethyl sulfate (DMS) footprinting. Surprisingly, CD spectroscopy shows a stable parallel G-quadruplex structure formed within the duplex DNA of the NHE at temperatures up to 100°C. This structure has been characterized by DMS footprinting in the double-stranded DNA of the NHE. In transfection experiments, 10 μM TMPyP4 reduced the activity of the basal promoter of PDGF-A ∼40%, relative to the control. On the basis of these results, we have established that ligand-mediated stabilization of G-quadruplex structures within the PDGF-A NHE can silence PDGF-A expression.

Role of CL-100, a Dual Specificity Phosphatase, in Thrombin-induced Endothelial Cell Activation

Using a cDNA microarray screening approach, we have identified seven novel thrombin-responsive genes in human umbilical vein endothelial cells that were verifiable by Northern blot analysis. Among them CL-100, a dual-specificity phosphatase also known as MAP kinase phosphatase-1 (MKP-1), showed greatest induction by thrombin. Steady-state levels of CL-100 mRNA induction by thrombin peaked at 1 h and declined rapidly (t1/2 approximately 45 min). Induction by thrombin was protease-activated receptor-1-mediated, protein synthesis-independent, and transcriptionally regulated. Metabolic labeling followed by immunoprecipitation verified that the thrombin-induced CL-100 mRNA was translated into protein. We found that both Src-kinase and p42/p44 ERK activity are critical for thrombin-induced CL-100 expression, whereas phosphatidylinositol 3-kinase and protein kinase C activity were not required. Antisense-mediated inhibition of CL-100 was shown to prolong thrombin-induced ERK activity in endothelial cells, concomitant with an inhibition in thrombin-induced PDGF-A (platelet-derived growth factor A) and PDGF-B gene expression and an up-regulation in thrombin-induced VCAM-1 and E-selectin gene expression. Inhibition of ERK activation by PD98059 in endothelial cells was shown to potentiate thrombin-induced expression of PDGF-B (approximately 3-fold) while inhibiting thrombin-induced VCAM-1 and E-selectin gene expression by 60 and 70%, respectively. These results suggested that induced expression of the CL-100 phosphatase and its subsequent regulation of ERK activity play a key regulatory role in the thrombin signaling pathway and in the transcriptional regulation of pathologically important "endothelial cell activation genes."

Regulation of postnatal lung development and homeostasis by estrogen receptor beta.

Estrogens have well-documented effects on lung development and physiology. However, the classical estrogen receptor alpha (ERalpha) is undetectable in the lung, and this has left many unanswered questions about the mechanism of estrogen action in this organ. Here we show, both in vivo and in vitro, that ERbeta is abundantly expressed and biologically active in the lung. Comparisons of lungs from wild-type mice and mice with an inactivated ERbeta gene (ERbeta(-/-)) revealed decreased numbers of alveoli in adult female ERbeta(-/-) mice and findings suggesting deficient alveolar formation as well as evidence of surfactant accumulation. Platelet-derived growth factor A (PDGF-A) and granulocyte-macrophage colony-stimulating factor (GM-CSF), key regulators of alveolar formation and surfactant homeostasis, respectively, were decreased in lungs of adult female ERbeta(-/-) mice, and direct transcriptional regulation of these genes by ERbeta was demonstrated. This suggests that estrogens act via ERbeta in the lung to modify PDGF-A and GM-CSF expression. These results provide a potential molecular mechanism for the gender differences in alveolar structure observed in the adult lung and establish ERbeta as a previously unknown regulator of postnatal lung development and homeostasis.

Effect of BO-653 and probucol on c-MYC and PDGF-A messenger RNA of the iliac artery after balloon denudation in cholesterol-fed rabbits

Antioxidants have been proposed as a promising treatment for restenosis after percutaneous transluminal coronary angioplasty (PTCA), but their mechanism of action remains unclear. Here, we investigated the effect of antioxidants on gene expression in the artery after balloon denudation. We developed a sensitive ribonuclease (RNase) protection assay for the messenger RNA (mRNA) levels of immediate early (IE) genes ( c- jun, c- fos and c- myc), as well as platelet-derived growth factor-A (PDGF-A), platelet-derived growth factor-ß receptor, transforming growth factor-ß1, and vascular endothelial growth factor. New Zealand White rabbits were fed a 0.17% cholesterol diet containing vehicle, BO-653 or probucol, and balloon denudation for iliac arteries was performed. The iliac arteries were then removed at 4 h after the denudation, for IE genes, and 10 days after for growth factors and receptors. Both BO-653 and probucol significantly reduced neointimal thickening, compared with the control. In terms of gene expression, BO-653, but not probucol, significantly inhibited c- myc induction. On the other hand, probucol, but not BO-653, significantly inhibited PDGF-A expression. Neither treatment had any effect on the expression of other genes. These results suggest that antioxidants affect the gene expression of the neointimal response and that both BO-653 and probucol inhibit gene expression in specific manners.

New therapeutic strategy for gastric carcinoma: a two-step evaluation of malignant potential from its molecular biologic and pathologic characteristics.

A previous study of ours indicated that platelet-derived growth factor-A (PDGF-A) mRNA expression in biopsy specimens can identify a subgroup of high-risk gastric carcinoma patients, while clinicopathologic studies have shown that lymph node involvement is an important risk factor for predicting overall survival. To identify gastric carcinoma patients at high risk for recurrence, we assessed a two-step evaluation consisting of mRNA expression of tumor growth-related factors and the histopathologic findings. The reverse transcriptase-polymerase chain reaction (RT-PCR) was used to assay the gene expression of PDGF-A and transforming growth factor-beta1 (TGF-beta1) in 69 gastric carcinoma endoscopic biopsy specimens (prospective cohort). The corresponding gastric carcinoma surgical specimens were classified histologically. Finally, the patients' survival curves were calculated. The relationships among the mRNA expression, histopathologic findings, and survival period were analyzed statistically. Nodal involvement correlated with PDGF-A and TGF-beta1 mRNA expression in early and advanced carcinomas, respectively. Both PDGF-A mRNA and TGF-beta1 mRNA expression were independent preoperative prognostic indicators in advanced cases. The ratio of involved nodes (n1) to total perigastric lymph nodes dissected (percentage of involved nodes) was the most independent postoperative prognostic indicator in advanced cases. Early carcinomas were divided preoperatively into two types. Advanced carcinomas were divided preoperatively into three. These were divided again postoperatively according to the percentage of involved nodes into high- and low-malignacy groups. A two-step evaluation of the malignant potential of gastric carcinoma by a combination of preoperative evaluation for PDGF-A and TGF-beta1 expression and postoperative pathologic examination would yield a more accurate prognosis for patients with gastric carcinoma.

New therapeutic strategy for gastric carcinoma: A two‐step evaluation of malignant potential from its molecular biologic and pathologic characteristics

Background and Objectives A previous study of ours indicated that platelet-derived growth factor-A (PDGF-A) mRNA expression in biopsy specimens can identify a subgroup of high-risk gastric carcinoma patients, while clinicopathologic studies have shown that lymph node involvement is an important risk factor for predicting overall survival. To identify gastric carcinoma patients at high risk for recurrence, we assessed a two-step evaluation consisting of mRNA expression of tumor growth–related factors and the histopathologic findings. Methods The reverse transcriptase–polymerase chain reaction (RT-PCR) was used to assay the gene expression of PDGF-A and transforming growth factor-β1 (TGF-β1) in 69 gastric carcinoma endoscopic biopsy specimens (prospective cohort). The corresponding gastric carcinoma surgical specimens were classified histologically. Finally, the patients' survival curves were calculated. The relationships among the mRNA expression, histopathologic findings, and survival period were analyzed statistically. Results Nodal involvement correlated with PDGF-A and TGF-β1 mRNA expression in early and advanced carcinomas, respectively. Both PDGF-A mRNA and TGF-β1 mRNA expression were independent preoperative prognostic indicators in advanced cases. The ratio of involved nodes (n1) to total perigastric lymph nodes dissected (percentage of involved nodes) was the most independent postoperative prognostic indicator in advanced cases. Early carcinomas were divided preoperatively into two types. Advanced carcinomas were divided preoperatively into three. These were divided again postoperatively according to the percentage of involved nodes into high- and low-malignacy groups. Conclusions A two-step evaluation of the malignant potential of gastric carcinoma by a combination of preoperative evaluation for PDGF-A and TGF-β1 expression and postoperative pathologic examination would yield a more accurate prognosis for patients with gastric carcinoma. J. Surg. Oncol. 1999;72:142–149. © 1999 Wiley-Liss, Inc.

Temporal gradient in shear but not steady shear stress induces PDGF-A and MCP-1 expression in endothelial cells: role of NO, NF kappa B, and egr-1.

Three well-defined laminar flow profiles were created to distinguish the influence of a gradient in shear and steady shear on platelet-derived growth factor A (PDGF-A) and monocyte chemoattractant protein-1 (MCP-1) expression in human endothelial cells. The flow profiles (16 dyne/cm2 maximum shear stress) were ramp flow (shear stress smoothly transited at flow onset), step flow (shear stress abruptly applied at flow onset), and impulse flow (shear stress abruptly applied for 3 s only). Ramp flow induced only minor expression of PDGF-A and did not increase MCP-1 expression. Step flow increased PDGF-A and MCP-1 mRNA levels 3- and 2-fold at 1.5 hours, respectively, relative to ramp flow. In contrast, impulse flow increased PDGF-A and MCP-1 expression 6- and 7-fold at 1.5 hours, and these high levels were sustained for at least 4 hours. These results indicate that a temporal gradient in shear (impulse flow and the onset of step flow) and steady shear (ramp flow and the steady component of step flow) stimulates and diminishes the expression of PDGF-A and MCP-1, respectively. NO synthase inhibitor NG-amino-L-arginine (L-NAA) was found to markedly enhance MCP-1 and PDGF-A expression induced by step flow, but decrease their expression induced by impulse flow, in a dose-dependent manner. NO donor spermine-NONOate (SPR/NO) dose-dependently reduced the MCP-1 and PDGF-A expression induced by impulse flow. Moreover, impulse flow was found to stimulate sustained (4 hours) I kappa B-alpha degradation and egr-1 mRNA induction. L-NAA prevented I kappa B-alpha degradation, whereas SPR/NO increased I kappa B-alpha resynthesis 2 hours after impulse flow. Both L-NAA and SPR/NO inhibited the impulse flow inducibility of egr-1 4 hours after the flow stimulation. The results show that both NO induced by steady shear and NO donor inhibit temporal gradient in shear-induced MCP-1 and PDGF-A expression by downregulation of their respective transcription factors NF kappa B and egr-1, whereas NO induced by impulse flow stimulates MCP-1 and PDGF-A expression by upregulation of the transcription factors. The above findings suggest distinct roles of temporal gradient in shear and steady shear in atherogenesis in vivo.