Search PubMed⌕ Search

Biomedical subjects

D Coppola

Publications and source records attributed to D Coppola.

At least 55 records · Page 3Linked to original sources
PubMed1998

CD44V6 expression in human colorectal carcinoma.

CD44 is an adhesion molecule involved in cell-to-cell and cell-to-matrix interactions. This transmembrane glycoprotein exists in either standard or variant forms, originated by alternative splicing. One of the isoforms (CD44V6) has been shown, in some systems, to modify the metastatic potential of tumor cells. To investigate the role of this biomarker as possible prognostic antigen in colorectal cancer, we immunohistochemically analyzed the distribution of CD44V6 expression on formalin-fixed, paraffin-embedded tissues from resected colorectal cancers of 34 patients. The monoclonal antibody VFF7 against the amino acid sequence encoded by exon CD44V6 was applied using the avidin-biotin-peroxidase method. For each resected specimen, normal (N), adenomatous (AD), and carcinomatous (CA) colonic mucosa were tested. In 68% of the resected cases, these areas were present in the same slide, and in 76% of cases, nodal or liver metastases (MT) were available for evaluation. Adenomatous polyp biopsy specimens of 10 carcinoma-free patients were also tested. In selected cases, CD44V6 expression was also determined using the Western blot immunoprecipitation technique. CD44V6 immunoreactivity was detected in 100% of the ADs, and in 91% of CAs, but was mostly weak in only 38% of MTs (n=26). In 49% (n=35) of ADs, 11% (n=34) of CAs, and 4% of MTs (n=26), the stain was moderate to strong. CD44V6 immunoreactivity was predominantly membranous in ADs and cytoplasmic in MTs. In the CAs, both staining patterns were noted. Interestingly, the normal mucosa had a weak subnuclear localization of the stain. In the cases evaluated by Western blotting immunoprecipitation analysis, the level of CD44V6 protein expression was similar to that obtained by immunohistochemistry. No correlation was found with tumor type, stage, or patient survival. The predominant CD44V6 expression in ADs and CAs, but not in MTs, suggests that, in many cases, the expression of this adhesion molecule may be lost during the acquisition of migratory function by the tumor cells.

Adenocarcinoma↗
PubMed1998

Prognostic significance of p53, bcl-2, vimentin, and S100 protein-positive Langerhans cells in endometrial carcinoma.

Immunohistochemical expression of p53, Bc12, vimentin, and S100 protein-positive Langerhans cell was evaluated in 50 endometrial carcinomas (6 stage I, 14 stage II, 20 stage III, and 10 stage IV), in an attempt to use these markers as predictors of survival. Monoclonal antibodies to p53, Bcl-2, vimentin, and S100 proteins were applied to paraffin-embedded sections of endometrial adenocarcinoma, using the avidin-biotin peroxidase complex technique (ABC). All 20 patients with stage I and II carcinomas were alive with a mean follow-up of 3 years. Of 30 patients with stage III and IV carcinomas, 13 died of tumor (3-year survival, 57%; SE, 10%), eight were alive with tumor, and nine were alive with no evidence of tumor (mean follow-up, 46 months). Strong p53 positivity was present in 11 carcinomas (22%), including nine high-stage and two low-stage tumors. Bcl-2 positivity was identified in 33 tumors (66%). These tumors were mostly low stage; however, no correlation was found between Bcl-2 expression and prognosis. Vimentin positivity (P < .001), and tumor infiltration by a large number of S100 protein-positive Langerhans cells (P < .05) were associated with low-stage tumors. Vimentin was expressed in 23 carcinomas, including 70% of low-stage tumors and 20% of high-stage tumors. Most high-grade carcinomas were Langerhans cell depleted; most low-grade carcinomas showed >50 S100 protein-positive Langerhans cells/10 high-power fields. Our results indicate that Langerhans cell infiltration and vimentin positivity of tumor cells are favorable prognostic factors in endometrial carcinomas.

Adenocarcinoma↗
PubMed1998

Analysis of p53, p21WAF1, and TGF-beta1 in human ductal adenocarcinoma of the pancreas: TGF-beta1 protein expression predicts longer survival.

Loss of p53 and p21WAF1 expression have previously been reported in pancreatic adenocarcinoma. Despite these findings in several reports of oncogene and tumor suppressor gene alterations in pancreatic cancer, the clinical significance of these changes is still poorly understood. In an attempt to detect molecular prognostic markers for pancreatic carcinoma, we studied the immunohistochemical expression of p53, p21WAF1, and TGF-beta1 proteins in 42 pancreatic adenocarcinomas of the ductal type. The results were correlated with clinicopathologic findings to identify the markers with prognostic significance. p53 nuclear immunoreactivity was seen in 20 (48%) of the cases, and it was strong to moderate in 14 (33%) of them. p21WAF1 cytoplasmic positivity was found in 16 (38%) of the tumors, with 72% staining strong to moderate. TGF-beta1 stained the cytoplasm of the tumor cells in 13 (31%). Of the p53-negative cases, 12 (54%) exhibited p21WAF1 expression. In 3 (30%) of cases, TGF-beta1 reactivity was seen in the absence of p53 and p21WAF1 p53 positivity identified tumors of higher grade, but did not correlate with stage or survival. TGF-beta1 expression, however, identified low-grade tumors and patients with longer survival. No correlation was found between the expression of any of these molecular markers and smoking history. We report a significant correlation between TGF-beta1 reactivity and low-grade tumors and between TGF-beta1 and better survival. This is a novel finding pointing to TGF-beta1 as a possible new stage-independent predictor of tumor survival in pancreatic ductal adenocarcinoma. In agreement with others, we also found p53 mutation in 20 (48%) of the tumors.

Adult↗
PubMed1998

Proton pump inhibitor-associated gastric polyps: a retrospective analysis of their frequency, and endoscopic, histologic, and ultrastructural characteristics.

Since 1992 there have been reports of proton pump inhibitors being associated with fundic gland-type gastric polyps. Endoscopic and histologic characteristics and natural history of these polyps have not been clearly defined. We performed a retrospective study of patients on long-term treatment with proton pump inhibitors who developed gastric polyps. Gastric polyps developed in 17 (10 males and 7 females, 7.3%) of the 231 patients who underwent 2 or more upper endoscopies for complicated gastroesophageal reflux disease and who were receiving long-term treatment with proton pump inhibitors. The mean interval of proton pump inhibitor use after which an endoscopy revealed gastric polyps was 32.5 months. In 1 patient, discontinuation of treatment resulted in disappearance of the polyps within 3 months. The polyps recurred 4 months after the treatment was restarted. Endoscopy established that typical polyps were generally small (<1 cm), sessile, multiple, and whitish pink with a mottled partially translucent surface. The polyps were most often present in the proximal/midgastric body. Of the 15 polyps removed endoscopically, 9 were of the fundic gland type, 4 were of the hyperplastic type, and 2 were of the inflammatory type. Eight of 9 polyps with typical endoscopic appearance were of the fundic gland type. None of the polyps contained dysplasia or carcinoma. Long-term use of proton pump inhibitors may be associated with the presence of small gastric fundic gland polyps and hyperplastic polyps. A prospective study is required to establish their incidence, natural history, and clinical significance.

Endoscopy, Digestive System↗
PubMed1998

Elevated c-Src protein expression is an early event in colonic neoplasia.

The molecular events regulating the development and progression of colonic neoplasia are currently being delineated. Recent studies have implicated c-Src protein kinase activation as an early event in the malignant transformation of colonic epithelial cells. However, increased c-Src activity has also been reported in colon carcinomas as well as in metastatic hepatic and extrahepatic colon carcinomas. To further investigate the potential role of c-Src in the progression of colonic neoplasia, we analyzed c-Src levels by immunohistochemistry in 27 colorectal resection specimens. Mouse monoclonal antibody to c-Src protein was applied to 3-micron sections from formalin-fixed, paraffin-embedded tissues using the avidin-biotin-peroxidase method. The combination of adenomatous (AD) and adjacent carcinomatous mucosa (CA) specimens were present in 20 of 27 patients. In 15 cases, synchronous metastatic (MT) lesions were available for evaluation. Strong c-Src expression was evident in 95% of AD (n = 20), in contradistinction to 32% of MT (n = 19) and 14% of CA (n = 22). Weak-to-moderate c-Src expression was seen in adjacent normal colonic mucosa (NM) in 96% of cases. Signed rank test univariate analysis revealed a statistically significant difference in c-Src expression between NM/AD (p = 0.0001), NM/CA (p = 0.0001), NM/MT (p = 0.0006), AD/CA (p = 0.0001), and AD/MT (p = 0.0002). No significant correlation between levels of c-Src expression and patient survival, tumor size, histologic grade, or tumor configuration was observed using the Cox's Regression Model. Similar results were obtained by analysis of c-Src protein levels and c-Src kinase activity as measured by Western blot and in vitro kinase assays of representative cases. Our results indicate that: (a) elevated c-Src expression is an important early event during colorectal carcinogenesis; (b) its activation may be involved in tumor progression in a subset of colonic carcinomas; and (c) additional molecular events are necessary for invasion to occur.

Adult↗
PubMed1997

Activation of c-Src by receptor tyrosine kinases in human colon cancer cells with high metastatic potential.

Recent data suggest that signal transduction may have a critical role in the development and regulation of the metastatic phenotype. Here, we investigated the role of c-Src activation in the process of human colon cancer metastasis to the liver. Our data, derived from two different sets of human colon cancer cell line metastatic variants, suggest that not only do highly-metastatic cells display constitutively elevated c-Src protein kinase activity when compared to poorly metastatic cells, but also that receptor tyrosine kinases participate in the ligand-activation of c-Src above basal levels. Specifically, the epidermal growth factor receptor (EGFR), p185HER2/Neu and the hepatocyte growth factor receptor (c-Met) appear to be linked to the process because they preferentially activate c-Src in highly-metastatic cells. EGFR was found to associate with c-Src in colon cancer cells and specific inhibitors of the EGFR resulted in a reduction of c-Src activity to basal levels. In addition, c-Src transfectants displayed partially-activated EGFRs, suggesting a feedback role for c-Src in the regulation of the EGFR. p185HER2/Neu was also identified in immunocomplexes of c-Src following ligand activation of the EGFR, but only in highly-metastatic cells. Collectively, these observations suggest a paradigm whereby c-Src interacts with multiple cell-surface growth factors in a catalytic fashion for the development of tumor cells with metastatic potential.

Colonic Neoplasms↗
PubMed1997

The efficacy of BAY y 1015 in dextran sulfate model of mouse colitis.

OBJECTIVE AND DESIGN: There is crucial evidence that leukotrienes are significant mediators of inflammation in inflammatory bowel diseases (IBD). Thus, selective inhibition of leukotriene synthesis is believed to provide a novel approach to therapy of IBD. The aim of the study is to study the efficacy of a potent 5-lipoxygenase activating protein inhibitor (FLAP), BAY y 1015 in a dextran sulfate model of mouse colitis. MATERIAL: Outbred female mice weighing approximately 25 grams were used to produce acute or chronic colitis by feeding 5% dextran sulfate in drinking water. TREATMENT: Colitic mice were treated with placebo (3% starch suspension, 0.1 ml. p.o., bid) or BAY y 1015 at 8 or 24 mg/kg, p.o., bid or olsalazine, 150 mg/kg/day, p.o. METHODS: Efficacy was determined by measuring daily disease activity index (DAI), quantitative histological scores, qualitative histology and measurement of tissue myeloperoxidase (MPO) and leukotriene B4 (LTB4) levels. RESULTS: BAY y 1015 was significantly more effective in improving the qualitative histology, inhibiting the DAI, inflammation scores (37-79%), crypt scores (28-71%), MPO (49-57%) and LTB4 levels (56-63%) compared to placebo treatment at all levels of colitis. The two doses of BAY y 1015 were equipotent in decreasing TLB4 levels. BAY y 1015 was significantly better than olsalazine in two of the three protocols used in this study. In the advanced disease level both doses of BAY y 1015 were equipotent in inhibiting crypt and (28-32%) inflammation scores (34-36%), LTB4 (34-56%) and MPO 41-49%) compared to olsalazine. CONCLUSION: This study suggests the possibility of investigating the use of this compound for the treatment of human inflammatory bowel diseases.

Animals↗
PubMed1997

Overexpression of normal c-Src in poorly metastatic human colon cancer cells enhances primary tumor growth but not metastatic potential.

Whereas genetic paradigms are now defined for the development of human colon cancer, little is known regarding the mechanisms that regulate development of the metastatic phenotype. Recent reports have indirectly linked the expression and activation of c-Src to the process of human colon cancer metastasis. Whereas v-Src, a highly activated mutational derivative of c-Src, has been shown to induce metastasis, normal c-Src has not been tested for this property. We hypothesized that c-Src overexpression in the milieu of a poorly metastatic cancer cell might permit the development of a highly metastatic cell. Two poorly metastatic human colon cancer cell lines were stably transfected with expression vectors encoding normal human c-Src. Clones producing 4-10-fold more c-Src than controls were injected s.c. and intrasplenically into the nude mouse to assess primary tumor growth and liver metastatic potential. Whereas metastatic potential was unaffected, primary tumor growth in vivo was significantly enhanced by c-Src overexpression. No effects on rates of tumor cell proliferation were seen in vitro. Our findings suggest that normal c-Src may be necessary but is insufficient for the induction of the metastatic phenotype.

Cell Division↗
PubMed1996

The extraordinarily rapid disappearance of entoptic images.

It has been known for more than 40 years that images fade from perception when they are kept at the same position on the retina by abrogating eye movements. Although aspects of this phenomenon were described earlier, the use of close-fitting contact lenses in the 1950s made possible a series of detailed observations on eye movements and visual continuity. In the intervening decades, many investigators have studied the role of image motion on visual perception. Although several controversies remain, it is clear that images deteriorate and in some cases disappear following stabilization; eye movements are, therefore, essential to sustained exoptic vision. The time course of image degradation has generally been reported to be a few seconds to a minute or more, depending upon the conditions. Here we show that images of entoptic vascular shadows can disappear in less than 80 msec. The rapid vanishing of these images implies an active mechanism of image erasure and creation as the basis of normal visual processing.

Arterioles↗
PubMed1996

Ethanol-induced inhibition of cell proliferation is modulated by insulin-like growth factor-I receptor levels.

Ethanol inhibits the tyrosine autophosphorylation of the insulin-like growth factor (IGF)-I receptor, an action that correlates with the inhibition of IGF-I-stimulated cell proliferation [J. Biol. Chem. 268:21777-21782 (1993)]. In the current study, the IGF-I-dependent proliferation of mouse BALB/c3T3 cells was completely inhibited by ethanol, but the growth of BALB/c3T3 cells that overexpress the IGF-I receptor (p6 cells) was only partially inhibited by ethanol BALB/ c3T3 cells that simultaneously overexpress both the IGF-I receptor and IGF-I were insensitive to growth inhibition by ethanol. In p6 cells, increasing concentrations of IGF-I overcame the inhibition of IGF-I receptor tyrosine autophosphorylation in the presence of ethanol. The importance of the IGF-I receptor as a specific target for ethanol was further investigated in C6 rat giloblastoma cells that respond mitogenically to both epidermal growth factor (EGF) and IGF-I. The mitogenic response of C6 cells to EGF was abrogated in cells expressing antisense mRNA to the IGF-I receptor. Thus, EGF action in these cells is dependent on activation of an IGF-I/IGF-I receptor autocrine pathway. Indeed, EGF stimulated an increase in IGF-I receptor levels by more than 100%. Ethanol completely inhibited the proliferation of C6 cells in response to either EGF or IGF-I. However, ethanol did not directly interfere with EGF receptor function, because EGF-induced cell proliferation was unaffected by ethanol when added exclusively during a 1-hr exposure to EGF. Ethanol did not interfere with the EGF-induced increase in IGF-I receptor expression. The addition of both EGF and IGF-I overcame the inhibitory action of ethanol. In conclusion, the potency of ethanol as an inhibitor of IGF-I-mediated cell proliferation correlates with the level of IGF-I receptors. In contrast to its effect on the IGF-I-receptor, ethanol has no direct effect on EGF receptor activation.

Animals↗
PubMed1996

Bcl-2, p53, CD44, and CD44v6 isoform expression in neuroendocrine tumors of the lung.

Immunohistochemical expression of p53, bcl-2, CD44 standard (CD44S), and the v6 isoform of CD44 (CD44v6) proteins were studied in 14 typical carcinoid tumors (TCs), 11 atypical carcinoids (ACs), and eight small cell carcinomas (SCLCs) in an attempt to use these markers of mutational events and cellular adhesion to discriminate neoplasms demonstrating neuroendocrine differentiation. p53 and bcl-2 overexpression were associated with more aggressive neuroendocrine cell types. p53 nuclear staining was weakly positive in 21% of the TCs, whereas strong nuclear staining was seen in 64% of the ACs and 88% of the SCLCs (P = 0.0047). bcl-2 was present in 21% of the TCs, 91% of the ACs, and 100% of the SCLCs (P = 0.0001). In contrast, CD44S and CD44v6 were inversely correlated with more aggressive types of neuroendocrine tumors. CD44S expression was moderate to strong in all of the TCs and 91% of the ACs but in only 37% of the SCLCs (P = 0.0018). There was no correlation between expression of these markers and tumor size or nodal status, although loss of CD44v6 was associated with lymph node metastases in the TC group only. In the spectrum of neuroendocrine tumors of the lung, p53 and bcl-2 overexpression correlates with more aggressive histologic cell types. The decreasing CD44S expression in AC and SCLC is similar to findings in cancer of the colon and in non-small cell carcinoma of the lung, where loss of CD44S is associated with poor prognosis. In AC and SCLC, but not in cancer of the colon, loss of CD44v6 correlates with more aggressive neoplasms and might correlate with lymph node metastases in TCs.

Adult↗
PubMed1996

CD44v6 expression in primary bronchioloalveolar carcinoma and conventional pulmonary adenocarcinoma.

CD44 is a family of transmembrane glycoproteins involved in cell-to-cell and cell-to-matrix interactions. Of the CD44 isoforms characterized, the v6 variant has been shown to confer metastatic potential in animal models and its expression has been correlated with aggressive behavior in some human malignancies. In an attempt to provide further insight into the heterogeneous appearance and behavior of bronchioloalveolar carcinomas (BACs), the pattern of CD44v6 staining in five mucinous, five nonmucinous, and eight sclerosing stage I BACs were compared with 12 comparably staged conventional pulmonary adenocarcinomas (CPAs). Formalin-fixed, paraffin-embedded sections were stained with monoclonal antibodies to CD44v6 (clone VFF-7). Neoplastic goblet cells, whether growing in a lepidic pattern in mucinous BACs or in an invasive pattern in CPAs, consistently demonstrated low level expression of CD44v6. In contrast, lepidic growth by neoplastic cells of type 2 pneumocyte or Clara cell differentiation demonstrated high levels in five of five cases of nonmucinous BACs, seven of eight cases of sclerosing BACs, and six of nine cases of CPAs. Similar cells of type 2 pneumocyte or Clara cell differentiation within the scarred area of sclerosing BAC demonstrated an intermediate degree of staining with four of eight cases marking with high levels, whereas none of the nine cases of CPAs with invasion by these cells showed high levels in the desmoplastic areas. From these results, two patterns of CD44v6 expression were recognized in BACs and CPAs. First, the expression appeared to be partly dependent on differentiation as cells demonstrating mucinous differentiation, whether in BACs or CPAs, consistently lacked CD44v6 staining. Second, in cells of type pneumocyte or Clara cell differentiation the expression was dependent on the growth pattern and their relationship to the stroma. High level expression was noted in neoplastic cells growing in a lepidic pattern, whereas those demonstrating invasion gradually lost the expression with increasing degrees of stromal reaction. Thus, the expression of CD44v6 in pulmonary BACs and similarly staged CPAs appears to be different from other human malignancies that have a positive correlation with aggressive behavior.

Adenocarcinoma↗
PubMed1994

Growth inhibition of human melanoma cells in nude mice by antisense strategies to the type 1 insulin-like growth factor receptor.

The growth of human melanoma cells FO-1 in nude mice is strongly inhibited or even abrogated when the cells are stably transfected with a plasmid expressing an antisense RNA to the insulin-like growth factor 1 receptor (IGF-1R) RNA, which causes a marked reduction in the number of IGF-1 receptors. When a tumor arises after a long delay in nude mice, it can be shown that the tumor cells have lost the expression plasmid and that the number of IGF-1 receptors has returned to wild-type levels. The antisense effect is even more remarkable, since the growth of FO-1 melanoma cells in monolayers is not affected by the expression of the antisense RNA. Inhibition of tumorigenesis was also evident when FO-1 melanoma cells were treated with antisense oligodeoxynucleotides to the IGF-1R RNA prior to injection into nude mice. These results confirm in human cells that the IGF-1R plays a dominant role in transformation and tumorigenesis and that its effect on tumorigenesis is more profound than its effect on mitogenesis.

Animals↗
PubMed1994

Rat glioblastoma cells expressing an antisense RNA to the insulin-like growth factor-1 (IGF-1) receptor are nontumorigenic and induce regression of wild-type tumors.

Insulin-like growth factor-1 (IGF-1) and IGF-2 are critical regulators of cell proliferation. The growth-promoting action of both ligands is mediated by the type 1 IGF receptor (IGF-1R). We have investigated the role of the IGF-1R in the growth and tumorigenicity of rat C6 glioblastoma cells. For this purpose, antisense RNA to IGF-1R RNA was introduced into cells by either the addition of oligodeoxynucleotides or by transfection with plasmids that express antisense RNA to IGF-1R RNA. At low cell density, C6 cells grew slowly in serum-free medium and proliferated with the sole addition of IGF-1 or IGF-2. Both antisense IGF-1R oligodeoxynucleotides and stable transfection with a plasmid expressing an antisense IGF-1R RNA inhibited IGF-1-mediated growth in monolayers and clonogenicity in soft agar. Sense oligodeoxynucleotides and sense-expressing plasmid had no effect on either parameter. In stable antisense transfectants, tyrosine-phosphorylated IGF-1 receptors were not detectable, although they were easily detected in wild-type cells. When wild-type C6 cells were injected s.c. into syngeneic immunocompetent rats, tumors developed within 1 week. In contrast, stably transfected C6 cells overexpressing antisense IGF-1R RNA were nontumorigenic. Moreover, when C6 IGF-1R antisense cells were injected, subsequent tumor formation by wild-type C6 cells was completely prevented. Finally, injection of C6 IGF-1R antisense cells into rats carrying an established wild-type C6 tumor caused complete regression of the tumors. The results demonstrate the critical importance of the IGF-1R in glioblastoma cell growth, clonogenicity, and tumorigenicity. Although the mechanism is presently unknown, the fact that the injection of C6 cells expressing an antisense RNA to IGF-1R RNA leads to regression of already established wild-type C6 tumors suggests the possibility of practical applications.

Animals↗
PubMed1994

Growth regulation of human glioblastoma T98G cells by insulin-like growth factor-1 and its receptor.

The interaction of insulin-like growth factors (IGFs) with the IGF-1 receptor is an important step in the control of cell proliferation and development. In particular, IGF-1 and IGF-2 are key regulators of central nervous system development, and may modulate the growth of glial tumors. We have investigated the growth factor regulation of the human glioblastoma cell line T98G. These cells growth arrested in serum-free medium at 34 degrees C, despite their secretion of substantial amounts of bioactive IGF-1. To be stimulated to divide, growth-arrested cells required the addition of platelet-derived growth factor (PDGF) or its equivalent, 1% serum. Cell proliferation in serum-free medium could also be obtained by shifting the cells to a temperature of 39.6 degrees C. Treatment of growth-arrested cells with PDGF or temperature shift was accompanied by a transient increase in the expression of the mRNA for the IGF-1 receptor. Transfection with a plasmid constitutively expressing the full cDNA for the human IGF-1 receptor allowed autonomous growth in serum-free medium at 34 degrees C. By contrast, growth induction by growth factors or temperature shift was abrogated by transfection of the cells with a plasmid expressing a 300 bp segment of mRNA antisense to the IGF-1 receptor mRNA. Cloning in soft agar was also inhibited by expression of antisense IGF-1 receptor mRNA. These results demonstrate that the IGF-1 receptor is strictly required for the growth of T98G glioblastoma cells. Moreover, the autocrine interaction of IGF-1 with its receptor regulates both autonomous and anchorage-independent growth of these cells.

Base Sequence↗