Characterization of monoclonal antibodies raised to C-terminal peptides of pS2: a major trefoil peptide and motility factor expressed in adenocarcinomas and regions of mucosal injury

Expression of trefoil factors and TWIST1 in colorectal cancer and their correlation with metastatic potential and prognosis

AIM

To detect the expression of trefoil factors (TFFs) and TWIST1 in colorectal cancer (CRC) and analyze their correlation with metastasis and survival.

METHODS

This study examined the expression of TFF1, TFF3 and TWIST1 in a total of 75 tumor samples, 47 matched normal samples (15 cm from the lesion margin), 30 metastatic lymph nodes, and 10 liver metastatic cancer samples from patients with CRC. The relationship was then analyzed between the protein expression and different clinical records. TFF1, TFF3, TWIST1,E-cadherin, vimentin and β-catenin mRNA and protein expression levels were measured in colon cancer cell lines with different metastatic potentials (HIEC, HT29, SW620, and LoVo cells), and the correlation of the expression levels with epithelial-mesenchymal transition (EMT) was discussed.

RESULTS

It was found that 66.7% (50/75), 78.7% (59/75) and 54.7% (41/75) of tumor tissue samples exhibited positive staining for TFF1, TFF3 and TWIST1 and so did 27.3% (13/47), 100% (47/47) and 17% (8/47) of adjacent normal colorectal tissues. Compared with adjacent normal tissues, significant differences were found in the expression of all three proteins in different cancerous tissues (P < 0.05). Higher expression of TFF3 and TWIST1 was significantly correlated with lymph node metastasis (P = 0.034, P = 0.000), advanced stage (P = 0.031, P = 0.003), and poorer survival (P = 0.042 for the TFF3 group, P = 0.003 for the TWIST1 group). The expression of TFF3 and TWIST1 in cancer cell lines was higher than that in HIEC (a normal human intestinal epithelial cell line)(P < 0.05), and the expression intensity demonstrated a tendency to rise with increased metastatic potential both at the protein and mRNA levels. However, TFF1 expression demonstrated the opposite tendency. It was also observed that the expression of E-cadherin and β-catenin tended to decrease while that of vimentin, TWIST1 and Snail tended to rise with the increase in metastatic potential.

CONCLUSION

The expression of TFF3 and TWIST1 might be associated with the survival of patients with CRC after curative resection and might be pivotal predictors of disease progression. TFF3 may be correlated to the invasiveness of CRC.

PS2 and HSP70 Expression in Rectal Adenocarcinomas

OBJECTIVE

To evaluate the expression of HSP70 and pS2 and to determine whether it may be an additional prognostic variable in the prediction of recurrence and survival in rectal adenocarcinomas.

METHODS

The paraffin sections of 45 patients with rectal carcinoma who were treated with surgical resection were stained with HSP70 and pS2 antibodies by using the standard biotin immunoperoxidase method. Cytoplasmic staining for both antibodies was scored semiquantitatively.

RESULTS

Only 16 (35.6%) tumors showed a positive cytoplasmic reaction with HSP70 antibody, while pS2 expression was observed in 26 (57.8%) tumors. There was an association between HSP70 and pS2 expression (P=0.002). No correlations were found between HSP70 and pS2 expression and tumor recurrence or overall survival and other prognostic factors. However, the type of surgical resection was significantly associated with pS2 expression status (P=0.013). Significant correlations were detected between tumor recurrence and other clinicopathologic parameters, such as clinical stage, lymph node involvement, and resection type (P=0.015, P=0.015, and P=0.03, respectively). Resection type was significantly associated with clinical outcome, recurrence, and metastasis (P=0.009, P=0.03, P<0.01, respectively). In addition, there was a statistically significant relationship between clinical stage and final outcome (P=0.005).

CONCLUSIONS

The strong correlation between pS2 expression and incomplete surgical resection suggests that pS2 may be related to invasive tumor behavior and may also play a role in tumor recurrence, although this latter association did not reach statistical significance in this study. HSP70 expression does not appear to be related to tumor invasiveness or tumor recurrence.

Distribution of TFF peptides in corneal disease and pterygium

The central cornea of 10 cadavers and 33 patients suffering from keratoconus, herpetic keratitis, Fuchs' dystrophy and pterygium were analysed focusing on the expression of TFF peptides by means of reverse transcription polymerase chain reaction and immunohistochemistry. TFF1 and TFF3 transcripts were detected in healthy corneae as well as in pterygia. Only TFF3 mRNA was transcribed in keratoconus, Fuchs' dystrophy and herpetic keratitis. Immunohistochemistry revealed absence of all three TFF peptides in healthy corneae but production of TFF3 in each of the diseased corneae. In pterygia both TFF1 and TFF3 synthesis was detectable in goblet cells. The absence of TFF peptide production in the healthy cornea indicates that TFF3 secretion is induced in different corneal diseases by yet unknown stimuli. Here TFF3 synthesis can be interpreted as a protection mechanism, because all corneal diseases analysed are characterized by progressive tissue destruction. TFF1 and TFF3 production by goblet cells in pterygia is comparable to the healthy conjunctiva suggesting that TFF peptides do not play a significant role in the pathogenesis of pterygia.

TFF1 is membrane-associated in breast carcinoma cell line MCF-7

Trefoil factor family (TFF) domain peptides, products of mucin-secreting epithelial cells, are thought to influence mucosal integrity. Molecular studies revealed that mammalian TFFs lack transmembrane domains. Using immunocytochemistry and FACS analysis we demonstrated the association of TFF1 with the cell membrane in MCF-7 (a breast adenocarcinoma cell line), and tested the hypothesis that glycosylphosphatidylinositol (GPI) linkage is the mechanism for this association. Cleavage of GPI anchorage using phospholipase C did not affect TFF1 binding to the cell membrane. Our results demonstrate for the first time that TFF1 is associated with the cell membrane of MCF-7 cells and is not linked via a GPI anchor.

Immunohistochemical detection of pS2 protein and heat shock protein-70 in pancreatic adenocarcinomas. Relationship with disease extent and patient survival

We investigated pS2 and HSP-70 protein expression in 36 pancreatic adenocarcinomas for their effect on disease extent and patient outcome. The cases were reviewed, histologically diagnosed, typed, graded, and staged. Lymphatic vessel, blood vessel and perineural invasion as well as lymph node, resection margin and adjacent organ involvements were re-evaluated. The standard streptavidin biotin immunperoxidase method was used for immunostaining with pS2 and HSP-70 antibodies. Cytoplasmic staining with both antibodies was scored semiquantitatively. The scores were compared with histopathological prognostic parameters using statistical methods. Standard prognostic parameters and staining scores were tested by survival analysis in terms of their effect on survival. All the tumors showed a positive cytoplasmic reaction with HSP-70 antibody. Seventy-seven percent of the tumors showed positive cytoplasmic staining with pS2 antibody (22.2% +, 13.9% ++ and 41.7% +++). There was a statistically significant difference between HSP-70 staining scores with N status and final stages of the tumors (Chi-square, p = 0.03 and p = 0.026, respectively), while neither direct nor inverse correlation was detected for both parameters. PS2 staining scores showed no statistically significant relationship with tumor grade T, M status, perineural invasion, lymph and blood vessel invasion. In tumors with extensive staining with pS2, tumor stage tended to be low (Chi square, p = 0.024, Kendall Tau-b, r: -0.336, p = 0.036). There was a statistically significant difference and inverse correlation between tumors with extensive pS2 staining and tumors with less intense staining in terms of lymph node metastasis (Chi-square, p = 0.041, Kendall Tau: p = 0.024, r = -0,373). In the R0 resection group, in univariate analysis, we found that with higher scores of HSP-70 staining, the prognosis of the patient tended to improve. (Cox regression, p = 0.013). In multivariate analysis, HSP-70 expression was found to be an independent prognostic factor. We found no relationship between pS2 staining and patient survival.

Characterization of gene expression profiles in intraductal papillary-mucinous tumors of the pancreas

The molecular pathology of precursor lesions leading to invasive pancreatic ductal adenocarcinomas remains relatively unknown. We have applied cDNA microarray analysis to characterize gene expression profiles in a series of intraductal papillary-mucinous tumors (IPMTs) of the pancreas, which represents one of the alternative routes of intraepithelial progression to full malignancy in the pancreatic duct system. Using a cDNA microarray containing 4992 human genes, we screened a total of 13 IPMTs including nine noninvasive and four invasive cases. Expression change in more than half of the tumors was observed for 120 genes, ie, 62 up-regulated and 58 down-regulated genes. Some of the up-regulated genes in this study have been previously described in classical pancreatic carcinomas such as lipocalin 2, galectin 3, claudin 4, and cathepsin E. The most highly up-regulated genes in IPMTs corresponded to three members of the trefoil factor family (TFF1, TFF2, and TFF3). Immunohistochemistry performed on five genes found to be differentially expressed at the RNA level (TFF1, TFF2, TFF3, lipocalin 2, and galectin 3) showed a good concordance between transcript level and protein abundance, except for TFF2. Hierarchical clustering organized the cases according to the dysplastic and invasive phenotype of theIPMTs. This analysis has permitted us to implicate several genes (caveolin 1, glypican 1, growth arrest-specific 6 protein, cysteine-rich angiogenic inducer 61) in tumor progression. The observation that several genes are differentially expressed both in IPMTs and pancreatic carcinomas suggests that they may be involved at an early stage of pancreatic carcinogenesis.

MUC1 mucin and trefoil factor 1 protein expression in renal cell carcinoma: correlation with prognosis

This study examines the coexpression of MUC1 mucin and trefoil factor 1 (TFF1) and their relationship to progression of renal cell carcinoma (RCC). Immunohistochemistry was performed on tumor and adjacent normal tissue from clear-cell RCC (n = 60) and tissues from normal controls (n = 5) using a set of well-characterized monoclonal antibodies recognizing different epitopes of MUC1 and TFF1. Results of immunohistochemistry were compared with clinical parameters, including tumor grade, tumor size, presence of metastasis, and progression-free survival of patients after surgery. In normal tissue, MUC1 and TFF1 were absent from the normal proximal tubular epithelium but were identified in distal and collecting tubular epithelium. In RCC, increased MUC1 expression positively correlated to tumor progression. MUC1 recognized by HMFG1 was associated with large tumor size (P < .05), distant metastasis (P < .05), and invasion of large veins (P < .05). Expression of the under-glycosylated form of MUC1 recognized by SM3 was found to correlate to time to progression (recurrence, metastasis, or death of patient; P < .001). Expression of TFF1 did not significantly correlate with any prognostic parameters. However, there was a significant correlation (P < .01) between TFF1 and MUC1 expression (HMFG2 epitope) in RCCs. These results are consistent with the following conclusions: (1) MUC1 may be an independent prognostic marker in RCC; (2) TFF1 is frequently coexpressed with MUC1 and may act synergistically; and (3) RCC may originate from distal tubular epithelium.

Human MUC1 mucin: a potent glandular morphogen

Human MUC1 mucin is a high-molecular-weight transmembrane glycoprotein, which is apically expressed in the majority of glandular epithelia. During embryonic development, changes in the pattern of MUC1 mucin expression coincide with the onset of glandular differentiation. This mucin is also frequently overexpressed and aberrantly glycosylated in carcinomas. To investigate the potential role of MUC1 mucin in morphogenesis, a full length MUC1 cDNA was transfected into murine mammary adenocarcinoma (410.4) and Madin-Darby canine kidney (MDCK) cells. This generated four clonal cell lines. Western blotting, FACS analysis, and immunohistochemistry confirmed expression of MUC1. All four MUC1-expressing clones demonstrated altered morphogenesis when cultured in three-dimensional type I collagen gels. While parental and vector control 410.4 cells formed compact spherical structures, the MUC1-expressing clones formed complex branching structures. Similarly, while parental and vector control MDCK cells formed small circumscribed colonies with a central lumen, the MUC1-expressing clones formed elongated tubules. MUC1 expression was also associated with reduced cellular cohesion and enhanced migration on type I collagen-coated surfaces for all except one of the clones, which expressed only low levels of MUC1 on the cell surface. These results show that MUC1 expression stimulates morphogenetic changes in two distinct epithelial cell lines. Taken together with previous observations on MUC1 expression in embryonic development and carcinomas, this finding suggests that MUC1 may induce changes in tissue architecture in both normal development and cancer.

Gastric carcinoma exhibits distinct types of cell differentiation: an immunohistochemical study of trefoil peptides (TFF1 and TFF2) and mucins (MUC1, MUC2, MUC5AC, and MUC6)

The expression of trefoil peptides (TFF1 and TFF2) and mucins (MUC1, MUC2, MUC5AC, and MUC6) has previously been described in gastric polyps. In the present study, the expression profile of these trefoil peptides and mucins was characterized in 96 gastric carcinomas, in an attempt to further the understanding of the histogenesis and cell differentiation of gastric carcinoma. Taking together the co-expression of trefoil peptides and mucins, three phenotypes were defined: complete gastric, incomplete gastric, and non-gastric phenotype. Gastric differentiation (complete and incomplete) was observed in 30 out of 33 (90.9%) diffuse carcinomas and in 38 out of 53 (71.7%) intestinal carcinomas. Non-gastric differentiation was observed in only three (9.1%) diffuse carcinomas and in 15 (28.3%) intestinal carcinomas. The phenotypes observed in intestinal carcinomas were similar to those previously observed in adenomatous polyps, whereas most diffuse carcinomas mimicked the phenotype of hyperplastic polyps. The percentage of cases displaying a non-gastric phenotype was higher, though not significantly, in tumours that had invaded the gastric wall than in T1 tumours, regardless of histotype. It is concluded that gastric-type differentiation is retained in the majority of gastric carcinomas, being more prominent in diffuse than in intestinal carcinomas, and in early than in advanced carcinomas.

Gastric carcinoma exhibits distinct types of cell differentiation: an immunohistochemical study of trefoil peptides (TFF1 and TFF2) and mucins (MUC1, MUC2, MUC5AC, and MUC6)

The expression of trefoil peptides (TFF1 and TFF2) and mucins (MUC1, MUC2, MUC5AC, and MUC6) has previously been described in gastric polyps. In the present study, the expression profile of these trefoil peptides and mucins was characterized in 96 gastric carcinomas, in an attempt to further the understanding of the histogenesis and cell differentiation of gastric carcinoma. Taking together the co-expression of trefoil peptides and mucins, three phenotypes were defined: complete gastric, incomplete gastric, and non-gastric phenotype. Gastric differentiation (complete and incomplete) was observed in 30 out of 33 (90.9%) diffuse carcinomas and in 38 out of 53 (71.7%) intestinal carcinomas. Non-gastric differentiation was observed in only three (9.1%) diffuse carcinomas and in 15 (28.3%) intestinal carcinomas. The phenotypes observed in intestinal carcinomas were similar to those previously observed in adenomatous polyps, whereas most diffuse carcinomas mimicked the phenotype of hyperplastic polyps. The percentage of cases displaying a non-gastric phenotype was higher, though not significantly, in tumours that had invaded the gastric wall than in T1 tumours, regardless of histotype. It is concluded that gastric-type differentiation is retained in the majority of gastric carcinomas, being more prominent in diffuse than in intestinal carcinomas, and in early than in advanced carcinomas.

Trefoil factor family domain peptides in the human respiratory tract

Trefoil factor family domain peptides (TFF) are thought to be involved in mucosal epithelial restitution and wound healing of the gastrointestinal tract and are up-regulated in ulceration and in a variety of solid tumours. It was hypothesized that TFFs are also expressed on mucosal surfaces of the human respiratory tract. Lung tissue, nasal polyps, and sputum samples from seven patients with cystic fibrosis (CF), two with chronic and acute bronchitis, and non-dysplastic material from two cases of bronchial adenocarcinoma were analysed for TFF expression by immunohistochemistry, immunofluorescence, western blot and RT-PCR. Expression of TFF1 and TFF3 was observed in material from all patients. TFFs were localized in goblet and ciliated cells, as well as in some submucosal cells of tracheobronchial tissues and nasal polyps from normal and CF individuals. In sputa of patients with CF and with chronic or acute bronchitis, TFF1 and TFF3 were detected by western blotting. Freshly cultivated nasal epithelial cells transcribed and secreted TFFs and mucins, whereas nasal cells cultivated for 6 weeks still expressed mucins, but not TFFs. Secreted TFFs and mucins also bound to the surface of Staphylococcus aureus in infected CF airways. In conclusion, TFF1 and TFF3 are expressed and secreted in normal and inflamed airways. The association of TFFs with bacteria may contribute to the anti-microbial mucociliary defence system.

The trefoil peptide TFF1 inhibits the growth of the human gastric adenocarcinoma cell line AGS

TFF1 is a 60-amino acid peptide produced in normal gastric mucosa which forms dimers spontaneously. Tumours of patients with gastric cancer usually have reduced TFF1 levels and disruption of the TFF1 gene causes animals to develop gastric adenomas and carcinomas. The effect of normal sequence human recombinant TFF1 and an analogue (Cys(58)-->Ser(58)), which is unable to dimerize, on the proliferation and morphology of the human gastric adenocarcinoma cell line AGS was therefore investigated. Proliferation, assessed by total cell number and [methyl-(3)H]thymidine incorporation, was reduced by dimeric TFF1 in a dose-dependent manner. Monomeric TFF1 also reduced proliferation but was less potent than the dimeric form. It is concluded that TFF1 may be an important controller of gastric cell proliferation, that dimerization of TFF1 is important in this effect, and that the reduced levels of TFF1 seen in gastric cancer may be of clinical relevance.

Dimerization of human pS2 (TFF1) plays a key role in its protective/healing effects

Human pS2 (trefoil factor family 1, TFF1), a 60-amino acid member of the trefoil peptide family, forms dimers via Cys58 and may stimulate gut repair. The effects of dimeric pS2-TFF1 and monomeric pS2-TFF1 (Cys58 replaced by Ser58) were compared in models of wound healing. Rats given dimeric pS2-TFF1 at 25 and 50 micrograms/kg per h had 50 per cent and 70 per cent reduction in gastric damage induced respectively by indomethacin (20 mg/kg subcutaneously) and restraint (P < 0.01). Monomeric pS2-TFF1, at the same doses, was significantly less effective at reducing injury (about half the amount of protection, P < 0.01 vs. same doses of dimeric). The rate of migration of cells at the leading edge of wounded monolayers of the human colonic cell line HT29 was increased by addition of dimeric or monomeric forms of pS2-TFF1 (0.65-325 micrograms/ml). Dimeric pS2-TFF1 had a greater effect than the monomeric form at all doses tested (P < 0.05). Cell migration induced by pS2-TFF1 was blocked by a pS2-TFF1 antibody, but not by a transforming growth factor beta neutralizing antibody. pS2-TFF1 did not influence cell proliferation as assessed by thymidine incorporation. The increased biological effects of dimeric pS2-TFF1 might be due to direct interaction of Cys58 with a putative trefoil receptor or, more likely, dimerization of pS2-TFF1 might stabilize the interaction with its receptor. This may involve a bivalent interaction of residues on the surfaces of the two trefoil domains.

The pS2 protein in colorectal carcinomas and metastases

Expression of pS2 protein in 50 primary tumors, metastases and recurrent tumors of colorectal carcinomas has been analyzed by immunohistochemistry. Sixty percent of the primary tumors were at least focally positive for the antigen. There was no correlation between pS2 expression and histologic grade of the lesions. In contrast, pS2 expression in T4 and T3 tumors was significantly higher than in T2 carcinomas. Immunoreactions in carcinomas with distant metastases (MI) were stronger than in M0 cases. However, this difference did not reach statistical significance. The presence of lymph node metastases did not correlate with pS2 expression. High expression of pS2 in T4 and T3 carcinomas together with the finding of pronounced expression of the antigen at invasion fronts in single cases could be interpreted as a function in tumor cell invasion and motility. However, in metastases and recurrent tumors, pS2 expression did not differ from primary lesions (53% positive lesions). All in all, under consideration of the latter finding in particular and together with the randomly distributed immunopositive tumor cells and cell clusters in the majority of cases, it is more likely that the expression pattern of pS2 in colorectal carcinomas is a result of overall tumor cell heterogeneity.