The use of kallikrein-related peptidases as adjuvant prognostic markers in colorectal cancer.

Several members of the human tissue kallikrein-related peptidase (KLK) family are emerging cancer biomarkers. The aim of this study was to analyse the expression of a panel of KLKs in colorectal cancer and to find out if the multiparametric combination of them can increase the accuracy of prediction of patients survival beyond the traditional clinical information. Nine KLKs (KLK5-8, KLK10, KLK11, KLK13-15) were measured using ELISA assays in cytosolic extracts of 122 colon cancer tissues and their nearby normal mucosa, obtained during surgery. The mean levels of almost all KLKs in tumour tissues were significantly different from their counterparts of normal tissue (P<0.0001). KLK 5, 6, 7, 13, 14 were significantly associated with overall survival in univariate analysis, but after adjusting for age, TNM and differentiation stage, only KLK5 (HR: 1.24 (95% CI: 1.05-1.47)), KLK7 (HR: 1.57 (95% CI: 1.04-2.37)) and KLK14 (HR: 1.43 (95% CI: 1.05-1.94)) remained significant. Addition of a panel of selected KLK markers to clinical parameters gave an increment in AUC of 0.86 beyond the clinical factors at year 1, showing that it can increase the accuracy of prediction of overall survival beyond the traditional clinical information, particularly the short-term (1 year) survival after surgery.

The PRMT1 gene expression pattern in colon cancer.

The methylation of arginine has been implicated in many cellular processes, such as regulation of transcription, mRNA splicing, RNA metabolism and transport. The enzymes responsible for this modification are the protein arginine methyltransferases. The most abundant methyltransferase in human cells is protein arginine methyltransferase 1. Methylation processes appear to interfere in the emergence of several diseases, including cancer. During our study, we examined the expression pattern of protein arginine methyltransferase 1 gene in colon cancer patients. The emerging results showed that the expression of one of the gene variants is associated with statistical significant probability to clinical and histological parameters, such as nodal status and stage. This is a first attempt to acquire an insight on the possible relation of the expression pattern of protein arginine methyltransferase 1 and colon cancer progression.

Cytokinetic and cytotoxic effects of urea on HeLa cells in suspension cultures.

Total and viable cell counts, differential mitotic cell counts, and incorporation of tritiated thymidine were used to study the kinetics of suspension cultures of HeLa cells exposed to urea concentrations of 0.5-1.5%. Aside from any nonspecific osmotic effects, urea concentrations of 1.0-1.4% exhibited significant cytokinetic and cytotoxic effects. Most characteristically, mitotic cells arrested in metaphase began to accumulate 4-6 hours after addition of urea and reached a peak at 15-18 hours. Thus when the cells were in the S-phase or at the S/G2 boundary at the time of addition of urea, they exhibited metaphase arrest. Subsequently, cultures continuously exposed to urea showed a decline in the mitotic index, indicating that the entry rate of cells into mitosis is lower than the rate at which cells escape from the mitotic block. Such cultures exhibited numerous abnormal and abortive mitoses and a decrease in growth and viability of the cell populations. In contrast to the initial single wave of arrested mitosis seen with continuous exposure to urea, intermittent exposure on alternate days resulted in successive waves of arrested metaphases and had considerably more pronounced effects on the growth and viability of the cultures.

Polyadenylate polymerase enzymatic activity in mammary tumor cytosols: A new independent prognostic marker in primary breast cancer.

Polyadenylate polymerase (PAP) is one of the enzymes involved in the formation of the polyadenylate tail of the 3' end of mRNA. High levels of PAP activity were associated with rapidly proliferating cells. Here we evaluate the prognostic value of PAP activity in breast cancer patients. PAP specific activity values were measured by a highly sensitive assay in the tumor cytosols of 228 women with primary breast cancer. The median follow-up period was 58 months. PAP specific activity values ranged from 2.1-39.4 units/mg protein in the breast tumor cytosols, and the activity was correlated with the level of expression of the antigen. An optimal cutoff value of 5.5 units/mg extracted protein was first defined by statistical analysis. PAP status was then compared with other established prognostic factors in terms of relapse-free survival (RFS) and overall survival (OS). PAP activity levels had a tendency to increase with tumor-node-metastasis (TNM) stage and were higher in node-positive patients. Evaluation of the prognostic value of PAP was performed using univariate and multivariate analyses. Univariate analysis showed that PAP-positive patients had a less favorable prognosis for both RFS (relative risk (RR) = 2.35; P < 0.001] and OS (RR = 3.15; P < 0.001). PAP significantly added to the prognostic power for RFS (RR = 2.51; P = 0.0012) and OS (RR = 4.21; P < 0.001) in multivariate analysis, whereas patient age, tumor size, and nodal and ER status remained independent factors for predicting survival. When only node-negative patients were examined, PAP was found to be an independent factor for predicting RFS (RR = 3.68; P = 0.0032) and OS (RR = 4.81; P < 0.001). PAP did not appear to have a prognostic significance for node-positive patients. PAP is a new prognostic factor for early recurrence and death in breast cancer patients. Our results suggest that PAP may be used as an independent unfavorable prognostic factor in node-negative breast cancer patients because there were no significant associations between PAP and the other prognostic indicators evaluated in this group of patients.

Chromogenic in situ hybridization analysis of chromosomes 7, 9, and 17 in pancreatic ductal adenocarcinoma based on tissue microarrays.

PURPOSE: Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive neoplasm. Many different chromosomal alterations have been identified including structural or numerical changes. In this study we performed a molecular analysis of chromosomes 7,9, and 17 based on tissue microarrays (TMA). MATERIALS AND METHODS: Using TMA technology, 50 paraffin-embedded tissue samples of histologically confirmed primary PDACs were cored twice and re-embedded to the final recipient block. Chromogenic in situ hybridization (CISH) was performed using centromeric probes of the corresponding chromosomes. SPSS(chi square test and interrater kappa) was performed for statistical analysis. RESULTS: Chromosome 17 analysis detected aneuploidy in 19 (38%) cases. Similarly, aneuploidy regarding chromosome 9 was identified in 9 (18%) cases, whereas 14 (28%) cases were aneuploid, concerning chromosome 7. Statistical significance was assessed, correlating chromosome 7 with grade and stage (p=0.016 and p=0.027, respectively) and chromosome 9 to grade (p=0.023). Similarly, analyzing normal-appearing ductal epithelia adjacent to cancer cell populations, 2 cases were found with alterations regarding chromosome 9 and 17. CONCLUSION: Molecular analysis for chromosomes 7, 9 and 17 in PDAC confirmed that there is a variety of numerical alterations, and some of them represent very early genetic events in the progression of carcinogenetic process. Performance of CISH, also, provides an easy, accurate approach for their detection, even in a small tissue sample, such as TMA cylindrical cores.

Predictive value of c-erbB-2 and cathepsin-D for Greek breast cancer patients using univariate and multivariate analysis.

The value of various prognostic factors in breast cancer patients has been determined in a number of studies. One hundred thirty-eight Greek women were followed up over a 5-year period after surgery for breast cancer. Amplification and overexpression of c-erbB-2 was found in 22.4% and 29.7% of the respective cases, and the concentration of total cytosolic Cathepsin-D (CD) in 46.4% of them was high (> or = 60 pmol/mg protein). The examined biological variables were compared with standard clinicopathological prognostic factors for the disease and related to early relapse (ER; before 3 years), relapse-free survival (RFS; median, 5 years), and overall survival (OS; median, 5 years). It was found that high CD levels significantly shorten ER of both node-negative and node-positive patients (P < 0.0001 and P = 0.002, respectively) and have prognostic value for RFS and OS of node-negative patients (P = 0.0012 and P = 0.0288, respectively), but lose their value as relapse predictors for node-positive patients for periods longer than 3 years. Overexpression of c-erbB-2 was found to be predictive for OS of node-positive and -negative patients (P = 0.0048 and P = 0.0285, respectively), but its predictive power was weak for ER (P = 0.0456) and RFS (P = 0.0455) of node-negative patients and disappeared for node-positive patients. c-erbB-2 amplification offers minimal assistance to the prediction. In conclusion, high CD concentration is indicative of ER of patients, and c-erbB-2 overexpression correlates with OS of patients.

Development of a quantitative luminometric hybridization assay for the determination of telomerase activity.

OBJECTIVES: To develop a quantitative luminometric hybridization assay for the determination of telomerase activity in tissue and cell extracts. DESIGN AND METHODS: Quantification is based on the coamplification of telomeric repeats synthesized by telomerase along with a specifically designed recombinant DNA-internal standard (DNA-IS). The DNA-IS has a similar size and the same primer recognition sites as the telomerase DNA products and differs from them only in a central 18 bp sequence. PCR products are captured on microtiter wells via the biotin-streptavidin system and hybridized with two distinct digoxigenin-labeled oligonucleotide probes that are designed to recognize specifically telomerase products and DNA-IS. The hybrids are quantified by a luminometric reaction using an antidigoxigenin antibody conjugated to alkaline phosphatase. The hybridization assay was validated with the MCF-7 breast carcinoma and leukemia K-562 cell lines and a synthetic telomerase product (R(8)). RESULTS: Luminescence ratios for telomerase products and DNA-IS were linearly related to the concentration of the pre-PCR product synthesized by telomerase (R(8)), in the range of 0.0005 to 10 pM. The overall reproducibility of the assay (between-run) varied between 11.3 and 15%. Application of the method in eleven breast tumors showed a great variation in the levels of telomerase enzymatic activity. CONCLUSIONS: The proposed luminometric hybridization assay for the quantitative determination of telomerase enzymatic activity is highly sensitive and can be used for a large-scale prospective evaluation of clinical samples.

c-erbB-2 overexpression may be used as an independent prognostic factor for breast cancer patients.

Insight into correlations between specific gene amplification and the clinical behavior of tumors may provide new prognostic tools High c-erbB-2 expression is an early feature in some breast tumors, whereas c-myc may be involved in the development of neoplasia. After an initial flurry of excitement about their prognostic significance, controversy has arisen about their independent importance. In an attempt to solve this problem, we decided to study c-erbB-2 and c-myc amplification and overexpression in 62 unselected breast carcinomas. This was done in order to correlate them statistically with one another, as well as with other prognostic parameters. A positive correlation was discovered between c-erbB-2 amplification and overexpression (P = 0.02); however, the correlations between c-erbB-2 amplification and c-myc amplification and overexpression (P = 0.06 and P = 0.095 respectively) were found to be negative. In addition, no correlation was found to exist between c-erbB-2 amplification and Cathepsin-D, steroid receptors, node status and menopausal status, as well as between c-erbB-2 overexpression and Cathepsin-D, node invasiveness, tumor status, grade or menopausal status. In conclusion, the c-erbB-2 overexpression has positive correlation with only a few other prognostic parameters, and therefore can be used as an independent prognostic factor.

Cathepsin-D and c-erb-B 2 have an additive prognostic value for breast cancer patients.

In breast cancer, axillary lymph node invasiveness is the major prognostic factor in predicting relapse and metastasis. Nevertheless, since 30% of node-negative tumours also relapse, it is necessary to develop other independent prognostic factors. Oncogene amplification and overexpression as well as the level of cathepsin-D have been proposed as additional prognostic factors. Recent studies suggest that the acidic lysosomal proteinase cath-D, present in all cells and known to be secreted in breast cancer cells, may be implicated in the process of tumour invasion and metastasis. We have compared the cytosolic cath-D level with the amplification and the overexpression of the oncogenes c-myc and c-erb-b-2 in 62 breast carcinomas (52 primary and 10 metastatic). Using a cut-off level of 60 pmol/mg protein, the status of cath-D showed a positive correlation with c-myc amplification (P = 0.01) or overexpression (P = 0.02). In contrast, no correlation was found between cath-D and c-erb-B-2 amplification or overexpression. Also, no correlation was found between cath-D and established prognostic factors such as node invasiveness, steroid receptors, grade and menopausal status. Nevertheless, a weak correlation was found between cath-D levels and tumour status (P = 0.05). In conclusion, in breast cancer, a high cytosolic cath-D concentration is more frequent in tumours with c-myc amplification and overexpression but is dissociated from c-erb-B-2 amplification or overexpression, suggesting that the determination of cath-D, as well as the latter two markers, will have an additional prognostic value.

Poly(A)polymerase activity levels in breast tumour cytosols.

The enzyme poly(A) polymerase (PAP) catalyses the polyadenylation of mRNA and its activity levels vary within the cell cycle. The levels of activity of this enzyme were measured in the cytosol of breast tumours from 62 untreated patients and compared to clinical prognostic parameters as well as other biological markers. The enzyme levels measured ranged from 3 to 46 units/mg protein. A statistically significant association was observed between high PAP activity values and the TNM stage of the disease as well as node invasiveness. Furthermore, there was a positive correlation between PAP activity values and c-erbB-2 overexpression but not with its amplification. No significant correlation was observed with c-myc amplification or overexpression and cathepsin D levels. A direct relationship between steroid receptor content and PAP activity levels, which was more prominent in the case of the progesterone receptor, was observed. However, also on the basis of previous data PAP activity may prove to be indicative of aggressive disease. Furthermore, measurements of PAP activity may contribute to the definition of the biological profile of tumour cells.

Kallikrein-related peptidases (KLKs) in gastrointestinal cancer: mechanistic and clinical aspects.

The human tissue kallikrein (KLK1) and kallikrein-related peptidases (KLKs) are secreted serine proteases with diverse expression patterns and physiological roles in different systems, including the digestive system. The aberrant expression of KLKs in gastrointestinal malignancies as well as their implication in carcinogenesis including cell growth regulation, angiogenesis, invasion, and metastasis, has prompted scientists to investigate their potential as cancer biomarkers. Expression of distinct KLKs is associated with various clinic-pathological parameters of patients with gastric, colorectal, pancreatic, hepatic, and esophageal cancer. Moreover, several KLKs possess significant favourable or unfavourable prognostic value in these human malignancies. Identification of novel diagnostic, prognostic and predictive biomarkers will contribute utmost to clinical decision-making, since early diagnosis of gastrointestinal cancer and early detection of recurrence following surgery are critical for the effective treatment of patients and for a positive clinical outcome. The current review provides a brief overview of the functional role of KLKs in gastric, colorectal, pancreatic, hepatic, and esophageal cancer, and describes the current status of KLKs as potential tumour biomarkers in these human malignancies.

mRNA quantification and clinical evaluation of telomerase reverse transcriptase subunit (hTERT) in intracranial tumours of patients in the island of Crete.

Telomerase is a reverse transcriptase that maintains telomeres by adding telomeric TTAGGG repeats to the ends of human chromosomes. The aim of this study was to evaluate quantitatively the mRNA expression of telomerase catalytic subunit (hTERT) in different types of intracranial tumours in relation to their histologic pattern and grade and correlate it with progression-free (PFS) and overall survival (OS) of patients. Human telomerase reverse transcriptase mRNA levels were estimated by the use of real time RT-PCR in 68 samples of intracranial tumours. It revealed statistical correlation between hTERT mRNA expression levels and the grade of the tumours (P<0.001). Patients having negative expression of hTERT mRNA had statistically longer PFS (P=0.031) and OS (P=0.047). Cox univariate regression analysis revealed that hTERT mRNA-positive patients had a high and statistically significant risk of relapse (hazard ratio (HR) of 2.24 and P=0.038). In the Cox multivariate regression model, the levels of hTERT mRNA were adjusted for tumour grade and patients age, and since there was statistically significant relationship between the levels of hTERT mRNA and the grade of the tumours (P=0.003 or P=0.006, respectively), hTERT mRNA levels could not be considered as an independent prognostic factor for PFS or OS.

Chromosomal aberrations in early stages of development of methotrexate resistance in HeLa cells.

High incidence of dicentrics, rings, double rings, acentric rod-like fragments and double minutes in polyploid cells during the early stages of development of methotrexate resistance in HeLa cells suggests that hypertetraploid cells are precursors of cells with higher resistance levels.

Cytogenetical changes during early stages of development of methotrexate resistance in HeLa cells.

HeLa cells cultured in ever-increasing doses of methotrexate (MTX) acquired resistance to this drug. Chromosomal changes occurring at early stages during the development of resistance to various doses (0.1, 0.3, 0.5, 1.0, 2.1, 3.0, 10.0 and 100.0 micrograms/ml) of MTX included: (a) an increase in the percentage of hypertetraploid cells (greater than 92 chromosomes) at all doses, and most profoundly at 1.0, 2.1 and 3.0 micrograms/ml; (b) an increase in the percentage of cells with structural abnormalities; (c) a remarkable increase in the percentage of hypertetraploid cells containing dicentrics, particularly at MTX dose levels 0.5-3.0 micrograms/ml and (d) emergence of increasing numbers of double minutes per cell with increasing MTX doses. At dose levels 2.1 and 3.0 micrograms/ml the modal chromosome number increased to 82, while at 0.1-1.0 microgram/ml it was similar to the mode of sensitive HeLa (64, 66) and at 10.0 and 100.0 micrograms/ml dropped to 62, 63. The results obtained suggest that polyploidization and formation of dicentrics are associated with the earlier stages of development of resistance to methotrexate.

Significance of urokinase-type plasminogen activator and plasminogen activator inhibitor-1 (PAI-1) expression in human colorectal carcinomas.

Despite the advances in the medical care of colorectal carcinoma patients, the prognosis has improved only marginally over recent decades. Thus, additional prognostic indicators would be of great clinical value to select patients for adjuvant therapy. In the present study, the antigen levels of urokinase-type plasminogen activator (uPA) and its inhibitor PAI-1, and their immunohistochemical staining were compared in paired colorectal tumor (n = 64) and background colon tissue of the same patients with clinical and pathological staging. The antigen levels, measured with an ELISA method, were found to be significantly higher in cancer tissue (mean 1.92 ng/mg protein for uPA and 7.08 for PAI-1) than in corresponding normal mucosa (0.29 ng/mg protein for uPA and 1.11 ng/mg protein for PAI-1). There was a positive correlation between uPA and PAI-1 antigen levels and clinicopathological parameters such as grade (p < 0.001 and p = 0.01, respectively), while for Dukes' stage, only PAI-1 correlated positively (p = 0.018). Nodal status correlated positively with uPA but not with PAI-1 antigen levels. Immunohistochemical localization of both antigens was observed mainly in cancer cells and much less in stromal cells. Staining intensity increased from adenoma to adenocarcinoma. The degree of staining was associated with grade, Dukes' stage and nodal status for uPA (p < 0.001, p = 0.002, p < 0.001, respectively) and only with grade for PAI-1 (p = 0.007).

Overexpression of matrix-metalloproteinase-9 in human breast cancer: a potential favourable indicator in node-negative patients.

Matrix metalloprotease-9 (MMP-9; 92 kDa type IV collaganase, gelatinase B) is regarded as, important for degradation of the basement membrane and extracellular matrix during cancer invasion and other tissue-remodelling events. In this study we evaluate the prognostic value of MMP-9, by immunoperoxidase staining in a series of 210 breast cancer tissues. The results were quantitated using the HSCORE system, which consider both staining intensity and the percentage of cells stained at given intensities. MMP-9 status was compared with the concentration of cytosolic Cathepsin-D and with other established prognostic factors, in terms of disease free survival and overall survival. The median follow-up period was 62 months. MMP-9 staining was observed primarily in cancer cells, and to a lesser degree in surrounding stromal cells. MMP-9 expression was not detected in normal breast tissue. Levels of MMP-9 expression below the cut-off point were more frequently observed in larger (P = 0.014), invasive ductal histologic (P = 0.037), progesterone receptor (PR)-negative and PR-strong positive tumours (P< 0.001), as well as samples belonging to patients with stage III-IV disease (P = 0.009) and age 45-55 years (P = 0.011). In univariate analysis, node-negative breast cancer patients with tumors positive for MMP-9 had a considerable reduction in risk for relapse (RR = 0.45;P = 0.039) or death (RR = 0.32;P = 0.009). Multivariate analysis indicated that MMP-9 status was an independent favourable predictor of OS (RR = 0.47;P = 0.034) in node-negative but not in node-positive patients. Our results suggest that MMP-9 may be an independent favourable prognostic factor in node-negative breast cancer patients. The overexpression of MMP-9 in breast cancer may be also used as a marker to subdivide node negative breast cancer patients in order to determine the optimal treatment modality.

Expression of gelatinase-A (MMP-2) in human colon cancer and normal colon mucosa.

Proteolytic enzymes, such as type IV collagenases (MMP-2 gelatinase A, 72-kD type IV collagenase and MMP-9 gelatinase B, 92-kD type IV collagenase) play an important role in tumor invasion and metastasis. In the present study the levels of MMP-2 antigenic concentration and immunohistochemical staining were compared in paired colorectal tumor (n = 64) and background colon tissue of the same patients with clinical and pathological staging. The antigenic concentrations were found to be statistically significantly higher in cancer tissue (mean 11.29 ng/mg protein) than in corresponding normal mucosa (10.23 ng/mg protein) (p = 0.008). There was also a positive correlation between MMP-2 antigenic concentration and clinicopathologic parameters such as grade (p < 0.001) and Dukes' stage (p = 0.001), but not with lymph node involvement. Immunohistological localization of MMP-2 was observed in tumor as well as in stromal cells. Staining intensity increased from adenoma to adenocarcinoma. The degree of staining was associated with grade (p < 0.001), Dukes' stage (p < 0.001) and lymph node involvement (p < 0.001).

Determination of c-myc amplification and overexpression in breast cancer patients: evaluation of its prognostic value against c-erbB-2, cathepsin-D and clinicopathological characteristics using univariate and multivariate analysis.

C-myc and c-erbB-2 amplification and/or overexpression as well as total cathepsin-D (CD) concentration have been reported to be associated with poor prognosis in breast cancer. The prognostic significance, however, remains somewhat controversial, partly because of discrepancies among the different methodologies used. We determined the amplification and overexpression of c-myc oncogene in 152 breast cancer patients and examined its prognostic value in relation to c-erbB-2 amplification and overexpression, high concentration of CD (> or = 60 pmol mg(-1) protein) and standard clinicopathological prognostic factors of the disease. High CD concentration, as well as c-myc amplification and overexpression, proved to be the best of the new variables examined for prediction of early relapse (ER; before 3 years). After multivariate analysis only CD remained significant, which suggests that the prognostic power of these variables is similar. Using univariate analysis we proved that c-myc amplification and overexpression were highly significant for disease-free survival (DFS) (P = 0.0016 and P = 0.0001 respectively) and overall survival (OS) (P < 0.0001 and P = 0.0095 respectively), although by multivariate analysis c-myc overexpression was statistically significant only for DFS (P = 0.0001) and c-myc amplification only for OS (P = 0.0006). With regard to c-erbB-2, only its overexpression appeared to be significant for DFS and OS, although after multivariate analysis its prognostic power was weaker (P = 0.030 and P = 0.024 respectively). c-myc amplification and overexpression exhibited a tendency for locoregional recurrence (LRR) (P = 0.0024 and P = 0.0075 respectively), however, their prognostic value was lower after multivariate analysis and only CD remained significant.

Genomic organization, physical mapping, and expression analysis of the human protein arginine methyltransferase 1 gene.

Protein arginine methyltransferases (PRMTs) regulate mRNA processing and maturation by modulating the activity of RNA-binding proteins through methylation. The cDNA for human PRMT1 (HRMT1L2) was recently identified. In this paper, we describe the complete genomic organization of the human PRMT1 gene (GenBank Accession No. AF222689), together with its precise chromosomal localization in relation to other neighboring genes. We have also examined its expression in a total RNA panel of 26 human tissues, the BT-474 breast carcinoma cell line, and 16 breast tumors. PRMT1, which spans 11.2 kb of genomic sequence on chromosome 19q13.3, is located in close proximity to the IRF3 and RRAS genes and is transcribed in the opposite direction. It is formed of 12 coding exons and 11 intervening introns, and shows structural similarity to other PRMT genes. Three PRMT1 isoforms exist as a result of alternative mRNA splicing. Amino acid sequence comparison of the splicing variants indicates that they are all enzymatically active methyl transferases, but with different N-terminal hydrophobic regions. PRMT1 expression was detected in a variety of tissues. We have shown that the relative prevalence of alternatively spliced forms of PRMT1 is different between normal and cancerous breast tissues. Although PRMT1 was not found to be hormonally regulated by steroid hormones in breast cancer cells, our results suggest that two variants of PRMT1 are down regulated in breast cancer.