Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0027651 (tumor)
 685,946 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The MSV-MDCK-INV invasive variant of Moloney sarcoma virus (mos) transformed MDCK cells express multiple beta-actin-rich pseudopodia (P. U. Le et al., Cancer Res. 58, 1631-1635, 1998). We show here that the tips of these actively protruding cellular domains are morphologically distinct presenting numerous blebs and selectively pass through 1-microm-pore filters. The pseudopodia were purified from the underside of the filters and a major protein component was identified as the glycolytic enzyme, glyceraldehyde-3-phosphate dehydrogenase (GAPDH). By confocal microscopy, GAPDH colocalized with actin in MSV-MDCK-INV pseudopodia localizing this glycolytic enzyme to this site of active actin polymerization. Inhibition of glycolysis with 2-deoxyglucose or oxamate induced a rapid transformation of beta-actin-rich pseudopodia into extended lamellipodia and prevented cell motility. A localized glycolytic supply of energy therefore regulates the formation of beta-actin-rich pseudopodial protrusions and thereby the motility of invasive tumor cells.
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PMID:Purification and characterization of beta-actin-rich tumor cell pseudopodia: role of glycolysis. 1091 99

Thymidylate synthase (TS) is thought to be one of the target genes that the E2F1 transcription factor binds to and regulates. However, the relationship between the expressions of TS and E2F1 in primary colon cancer specimens remains unclear. The aim of this study was to define the relation of TS and E2F1 gene expressions in tumor samples from 23 colon cancer patients. TS and E2F1 gene expressions were measured by TaqMan reverse transcription-PCR assay using glyceraldehyde-3-phosphate dehydrogenase (GAPDH) as an internal standard and expressed as a TS:GAPDH or E2F1:GAPDH mRNA ratio. A close relationship was found between TS gene expression and E2F1 gene expression (r2 = 0.598, P < 0.001) in 23 tumor samples analyzed. Surprisingly, a high correlation between TS gene expression and E2F1 gene expression was observed even in advanced tumors from stage IV colon cancer patients. These results suggest that transcription of the TS gene may be regulated by E2F1 in primary colon cancer specimens and that this gene-regulatory pathway from E2F1 to TS may be highly conserved during malignant progression. Four of the 23 patients showed TS overexpression with increased E2F1 expression. These results suggest that the ability of a tumor to increase TS expression may possibly be due to an overexpression of E2F1. Although the number of patients was relatively small, our study provides new insights into the molecular mechanisms underlying the regulation of TS expression in colon cancers.
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PMID:Thymidylate synthase expression correlates closely with E2F1 expression in colon cancer. 1091 14

To determine the antiviral effects of drugs targeted to hepatitis C virus (HCV) in chronic hepatitis patients, an accurate quantitative method with high sensitivity is needed. Reverse transcription nested polymerase chain reaction (RT-PCR) is the most sensitive method for the detection of HCV sequences in clinical specimens. However, this method is not quantitative. For this purpose, a quantitative competitive assay was developed that combines RT and PCR followed by image analysis to quantify HCV RNA. This assay targets the highly conserved 5' non-coding region of HCV and is based on the co-amplification of wild type HCV RNA with known amounts of mutant synthetic RNA. The mutant internal control used in these experiments differs from the wild type RNA by two nucleotide substitutions, which introduces an internal restriction enzyme site. In this report, this method was used to determine the levels of positive strand RNA in 11 HCV positive hepatocellular carcinomas (HCC) and compared these with adjacent non-tumorous liver tissue. To confirm that the difference in viral titers is not related to variations in the amount of RNA used in the assay, glyceraldehyde 3-phosphate dehydrogenase (GAPDH) mRNA was also assessed by competitive RT-PCR in all tissue extracts. Using this competitive assay it was determined that HCV RNA levels in the liver and tumor samples ranged from 10(3) to 10(6) molecules per microg of total RNA which is similar to previous reports. Interestingly, the amount of HCV in all the non-tumorous liver specimens were found to be significantly higher (P<0.05) than the surrounding tumors, while the GAPDH mRNA levels were found to be similar in both liver and tumor. Competitive RT-PCR is a sensitive, accurate and reliable method to determine HCV titers in clinical specimens. Using this method it was determined that malignant tumor cells harbor less HCV as compared with the surrounding non-tumorous liver cells.
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PMID:HCV RNA levels in hepatocellular carcinomas and adjacent non-tumorous livers. 1101 Oct 77

Tumor-derived circulating DNA has been found in the plasma of cancer patients. Alterations include decreased strand stability, mutations of oncogenes or of tumor suppressor genes, microsatellite alterations, and hypermethylation of several genes. RNA has also been found circulating in the plasma of normal subjects and cancer patients. Tyrosinase mRNA has been extracted from the serum of melanoma patients and subjected to RT-PCR. Moreover, the presence of cell-free EBV-associated RNA has been reported in the plasma of patients with nasopharyngeal carcinoma. Human telomerase comprises two RNA subunits, telomerase RNA template (hTR) and its catalytic component, telomerase reverse transcriptase protein (hTERT). Expression of these subunits correlates with telomerase activity. Using RT-PCR, we investigated whether these RNA subunits were present in the serum of 18 patients with breast cancer, 2 patients with benign breast disease, and 21 normal subjects. The presence of amplifiable RNA was confirmed in all tissue and serum samples using RT-PCR of glyceraldehyde-3-phosphate dehydrogenase RNA. hTR was found in 17 of 18 tumors (94%) and 5 of 18 serum samples (28%). hTERT was also detected in 17 of 18 tumors (94%) and in 4 of 16 available serum samples (25%). hTR and hTERT were undetectable in tissues and sera taken from 2 patients with benign disease and in the sera of 21 normal subjects. We conclude that RNA is detectable in the serum of breast cancer patients and that tumor-derived mRNA can be extracted and amplified using RT-PCR, even in patients with localized disease. This may have implications for cancer diagnosis and follow-up in the future.
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PMID:Telomerase RNA as a detection marker in the serum of breast cancer patients. 1105 Dec 24

We analyzed the expression of vascular endothelial growth factor (VEGF) messenger ribonucleic acid (mRNA) isoforms and platelet-derived endothelial cell growth factor (PDECGF) mRNA in bladder cancer. We also attempted to determine if correlation exists between their expression level and conventional clinical variables in patients with bladder cancer. Tissues obtained from 60 patients with bladder carcinoma were used for analysis. Expression levels of VEGF isoforms and PDECGF were examined using reverse transcription-polymerase chain reaction (RT-PCR). Correlations between the expression levels of each VEGF isoform and PDECGF and histopathologic findings were evaluated. Four VEGF isoforms corresponding to VEGF121, 165, 189, and 206 were detected in bladder cancer tissue by RT-PCR. Gene expression of all VEGF isoforms as a ratio of the target to glyceraldehyde 3-phosphate dehydrogenase (GAPDH) showed no correlation with pathologic stage of bladder cancer. However, with regard to relative expression levels of VEGF isoform, which is the ratio to the sum of total VEGF isoforms, the levels of VEGF206 and VEGF189 in tumor samples of grade pT2 or higher were significantly lower than those in tumors of grade pT1 or lower (P<.05). In contrast, the levels of VEGF121 in >/=pT2 tumors tended to be higher than those in </=pT1 tumors (P=.056). The expression level of PDECGF as a ratio to GAPDH in pT2</= tumors was significantly higher than that in either pTa or pT1 tumors (P<.05). Moreover, a higher expression level of PDECGF was observed in G3 tumors than in G1 tumors (P<.05). The results indicated that gene expression of VEGF isoforms do not play a significant role in tumor progression or invasion; however, the distribution of VEGF isoforms may play a role in tumor progression of bladder cancer. A high expression level of PDECGF correlated significantly with the tumor progression of bladder cancer.
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PMID:Expression of vascular endothelial growth factor isoforms and platelet-derived endothelial cell growth factor in bladder cancer. 1111 67

Colon cancer incidence and mortality rates are lower in females compared with males, and numerous epidemiological studies suggest that estrogen replacement therapy (ERT) reduces cancer risk in postmenopausal women. Two estrogen receptor (ER) subtypes, ERalpha and ERbeta, mediate genomic effects in target cells. The aim of this study was to determine the relative mRNA expression levels for ER subtypes and ERbeta isoforms in colon tumors, normal colonic mucosa, and colon cancer cell lines. ERalpha and ERbeta isoform mRNA levels were investigated in paired samples of colon tumors and normal mucosa from 26 patients using comparative reverse transcription-PCR and then Southern analyses. Constitutive steroid hormone receptor mRNA levels were determined for five colon adenocarcinoma cell lines using reverse transcription-PCR, and ERbeta levels were further studied in Caco-2 cells using Northern and Western analyses. ERbeta mRNA steady-state levels (relative to glyceraldehyde-3-phosphate dehydrogenase mRNA) were significantly decreased in colon tumors compared with normal mucosa in female patients. ERbeta1 and ERbeta2 isoform mRNA levels were significantly decreased in tumors from female patients, and ERbeta1 mRNA levels were also significantly lower in tumors from female patients compared with tumors from males. ERalpha mRNA levels were much lower than ERbeta levels and were similar between normal mucosa and tumor samples in both genders. ERbeta mRNA was detected in Caco-2, T84, and SW1116 cell lines and all lines were essentially negative for ERalpha mRNA. Caco-2 cells coexpressed ERbeta1, ERbeta2, and ERbeta5 mRNA, though a single protein transcript was observed. ERbeta protein was detected in normal colonic superficial epithelium, vascular smooth muscle and endothelium, and enteric neurons by immunohistochemistry. These data show that ERbeta is the predominant ER subtype in the human colon and that decreased levels of ERbeta1 and ERbeta2 mRNA are associated with colonic tumorigenesis in females. This information suggests that activation of ERbeta-mediated processes in the superficial colonic epithelium may have a role in the preventive effects observed for female gender and ERT usage.
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PMID:Expression of estrogen receptor (ER) subtypes and ERbeta isoforms in colon cancer. 1121 61

Alpha-feto protein (AFP) mRNA levels increase in hepatocellular carcinoma (HCC) cells as compared with non-neoplastic tissue. Therefore, detection of AFP mRNA in blood nuclear cells is useful for the evaluation of treatment efficacy and prognosis of HCC. In this study, simple and reproducible methods were developed to quantify AFP mRNA using the real-time RT-PCR assay (Taq Man assay). By using in vitro synthesized AFP and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) RNA, the sensitivity and dynamic range of the RT-PCR assay were established. AFP mRNA in both HCC and non-neoplastic tissue, as well as in cell lines, were measured using this assay system. The expression of the AFP mRNA level was normalized using the GAPDH house keeping gene product as an endogenous reference. AFP and GAPDH mRNA can be quantified in the range of 10-10(8) copies when using this quantitative assay. Among HCC cell lines, Huh 7 and HepG2 cells, respectively, represented 1.5x10(6) and 6.0x10(5) AFP mRNA/10(6) GAPDH mRNA, in contrast to 6, 23 and 230 AFP mRNA/10(6) GAPDH mRNA for HLE, HLF and PLC/PRF/5 cells, respectively. Other cell lines derived from stomach, pancreas, and colon cancers have 10 AFP mRNA copies/10(6) GAPDH mRNA. In liver tissue from patients with chronic hepatitis, and the non-neoplastic portion of the liver from HCC patients, AFP mRNA distributes from 2.5x10(3) to 5.8x10(4)/10(6) GAPDH transcripts. In contrast, AFP mRNA in tumor cells were more than 100-fold higher than that found in corresponding non-neoplastic portions in two patients who had a high level of AFP in serum. The establishment of the TaqMan quantifying system for AFP mRNA may have important clinical implications.
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PMID:Simple quantitative assay of alpha-fetoprotein mRNA in liver tissue using the real-time detection polymerase chain reaction assay - its application for clinical use. 1128 88

It is well known that iron plays an essential role in many biochemical reactions and that rapidly growing cells require more iron for their growth and metabolism than resting cells. Transferrin and its receptor are required for entry of iron into the cell. In contrast, ferritin is a cellular storage protein whose main function is to sequester excess ferric iron and thus prevent high concentrations of soluble ferric iron from becoming toxic to the cell. However, the clinical significance of both transferrin receptor and ferritin mRNA levels have not previously been described in tumors from breast cancer patients. In this study, tumor tissue mRNA levels of transferrin receptor and ferritin were quantitated on forty-two breast cancer patients. A highly sensitive non-radioisotopic cDNA polymerase chain reaction assay was used to quantitate expression of mRNA. The expression of glyceraldehyde-3-phosphate dehydrogenase served as the control. In the tumor tissue from the 42 breast cancer patients the transferrin receptor mRNA levels were significantly correlated to the ferritin H-chain mRNA levels (Spearman correlation r = 0.5433, p = 0.0002; Pearson correlation r = 0.6276, p < 0.0001). The level of amplified transferrin receptor complementary DNA was related to differentiation (ANOVA, p = 0.042) with poorly differentiated tumors having high levels of transferrin receptor mRNA. Further, the levels of amplified gene for ferritin heavy chain complementary DNA was directly related to axillary lymph nodes status (Student's t-test, p = 0.044), presence of metastatic disease (Student's t-test, p = 0.046) and clinical stage (stage I + stage II versus stage III + stage IV; Student's t-test, p = 0.0181). These results demonstrate that non-radioisotopic RT-PCR is a very sensitive method for determining mRNA levels in tumor tissue. Additionally, the quantitation of expression of transferrin receptor and ferritin heavy chain mRNA may be useful for assessing prognosis and guiding therapeutic decisions in breast cancer patients.
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PMID:Expression of transferrin receptor and ferritin H-chain mRNA are associated with clinical and histopathological prognostic indicators in breast cancer. 1129 1

The suitability of "real-time" quantitative reverse transcriptase polymerase chain reaction (RT-PCR) for the detection of isolated carcinoma cells in bone marrow was investigated by evaluating the expression of cytokeratin (CK)7, CK8, CK18, CK19, and CK20 in 17 gastrointestinal cancer cell lines, 64 control bone marrow specimens from noncancer patients, and 30 bone marrow specimens from patients with gastric or colorectal cancer. RT-PCR products for CK8 and CK18 were detected in all cancer cell lines, but only 16, 5, and 11 cell lines provided evidence for CK19, CK7, and CK20 transcription. Variable numbers of bone marrow specimens from noncancer patients demonstrated background transcription of CK8 (78.1%), CK18 (95.3%), CK19 (35.9%), CK20 (29.6%), and CK7 (16.7%). Maximal background transcription for CK8, CK18, and CK19 ranged from 52.2 to 56.1 copies/10(3) copies glyceraldehyde-3-phosphate dehydrogenase (GAPDH), the corresponding values of 0.06 and 0.76 copies for CK7 and CK20 being distinctly lower. When maximal background values were used as a threshold value to define positivity in tumor cell dilution experiments, sensitivity levels of one tumor cell in 10(4) bone marrow cells were determined for CK7 and CK20 RT-PCR assays. Maximal background expression values of the different CKs as obtained in the control series were exceeded once (CK20), twice (CK18 and CK19), and 18 times (CK7) in bone marrow specimens from cancer patients, with none of these specimens exceeding the maximal background expression value of CK8. We conclude that RT-PCR for CK8, CK18, and CK19 cannot be recommended for the detection of isolated tumor cells in bone marrow of cancer patients. On the other side, the limited number of gastric and colorectal cancer cell lines expressing CK7 and CK20 indicates that assay sensitivity for these CKs might be limited because of their selective expression by carcinoma cells.
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PMID:Transcription of cytokeratins 8, 18, and 19 in bone marrow and limited expression of cytokeratins 7 and 20 by carcinoma cells: inherent limitations for RT-PCR in the detection of isolated tumor cells. 1159 48

To identify novel tumor suppressor genes involved in ovarian carcinogenesis, we generated four down-regulated suppression subtraction cDNA libraries from two early-stage (stage I/II) and two late-stage (stage III) primary ovarian tumors, each subtracted against cDNAs derived from normal ovarian epithelial cell brushings. Approximately 600-700 distinct clones were sequenced from each library. Comparison of down-regulated clones obtained from early- and late-stage tumors revealed genes that were unique to each library which suggested tumor-specific differences. We found 45 down-regulated genes that were common in all four libraries. We also identified several genes, the role of which in tumor development has yet to be elucidated, in addition to several under expressed genes, the potential role of which in carcinogenesis has been described previously (Bagnoli et al., Oncogene, 19: 4754-4763, 2000; Yu et al., Proc. Natl. Acad. Sci. USA, 96: 214-219, 1999; Mok et al., Oncogene, 12: 1895-1901, 1996). The differential expression of a subset of these genes was confirmed by semiquantitative reverse transcription-PCR using glyceraldehyde-3-phosphate dehydrogenase (GAPDH) as control in a panel of 15 stage I and 15 stage III tumors of mixed histological subtypes. Chromosomal sorting of library sequences revealed that several of the genes mapped to known regions of deletion in ovarian cancer. Loss of heterozygosity (LOH) analysis revealed multiple genomic regions with a high frequency of loss in both early- and late-stage tumors. To determine whether loss of expression of some of the genes corresponds to loss of an allele by LOH, we used a microsatellite marker for one of the novel genes on 8q and have shown that loss of expression of this novel gene correlates with loss of an allele by LOH. In conclusion, our analysis has identified down-regulated genes, which map to known as well as novel regions of deletions and may represent potential candidate tumor suppressor genes involved in ovarian cancer.
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PMID:Identification of underexpressed genes in early- and late-stage primary ovarian tumors by suppression subtraction hybridization. 1178 86


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