Intermediate Filaments Of Epithelial Cells Research Articles

Tescalcin over-expression increases Keratin 18 and 19 in K562 cells

Tescalcin (TESC) has been shown to be essential in mammalian cells as a regulator of intracellular Ca2+. Ca2+ is a second messenger functioning in many metabolic pathways as well as in cell differentiation, cell size and the cell cycle. K562 cells over-expressing TESC change their morphology and adopt adherent properties. Considering differences in morphology may have been reflected in changes of the cytoskeleton, we focused on the expression levels of keratins, which are cytoskeletal intermediate filaments in epithelial cells and also expressed in K562. We over-expressed the TESC gene via lentiviral transduction and analyzed keratin 8 (K8), keratin 18 (K18), and keratin 19 (K19) expression.

Acute effects of cell stretch on keratin filaments in A549 lung cells.

Keratin filaments (KFs) comprise the intermediate filaments of epithelial cells and are well known for their cytoprotective properties and their mechanical resilience. Although, several studies have demonstrated KFs' remarkable tensile properties relatively little is known about acute implications of mechanical stretch on KFs in living cells. This includes structural effects on the KFs and their higher level assembly structures as well as posttranslational response mechanisms to possibly modify KF's properties. We subjected simple epithelial A549 lung cells to 30% unidirectional stretch and already after 10seconds we observed morphological changes of the KF-network as well as structural effects on their desmosomal anchor sites-both apparently caused by the tensile strain. Interestingly, the effect on the desmosomes was attenuated after 30seconds of cell stretch with a concomitant increase in phosphorylation of keratin8-S432, keratin18-S53, and keratin18-S34 without an apparent increase in keratin solubility. When mimicking the phosphorylation of keratin18-S34 the stretch-induced effect on the desmosomes could be diminished and probing the cell surface with atomic force microscopy showed a lowered elastic modulus. We conclude that the stretch-induced KF phosphorylation affects KF's tensile properties, probably to lower the mechanical load on strained desmosomal cell-cell contacts, and hence, preserve epithelial integrity.

Cytokeratin expression profiles of canine epithelial tissues.

Cytokeratins (CKs) are intermediate filaments of epithelial cells. In humans, different types of epithelia as well as their neoplasms show distinct CK expression profiles. The aim of this study was to establish a panel of CKs for the identification of specialized canine epithelia that can be integrated in a routine diagnostic setting. Immunohistochemistry was performed on 42 formalin-fixed paraffin-embedded (FFPE) canine unaltered tissues including all epithelial tissues by using an antibody panel detecting CKs 7, 8, 13, 14, 17, 19 and 20 and the pancytokeratin marker AE1/AE3. Using this antibody panel, a differentiation scheme for the identification of canine tissues was developed. This allowed the identification of 23 out of the 42 examined canine tissues and the distinction of 9 groups of specialized epithelia. The statistical validation revealed high variations in the immunoreactivity for CKs 7, 8, 14, 17 and 20 between the donor dogs. The antibody detecting CK 7 (OV-TL 12/13) showed a decrease in immunostaining after a fixation time of 3 and 4 days. To the best of the authors' knowledge this is the first study that characterizes all canine epithelial tissues for their expression of CKs 7, 8, 13, 14, 17, 19 and 20 and the pancytokeratin marker AE1/AE3. Results of this study are an important prerequisite for comparative histology and for the investigation into similarities/differences of the cytokeratin expression between normal and neoplastic epithelia. Since this study was performed on FFPE tissue, it can be included in the workflow of a routine diagnostic laboratory.

Epithelial Keratins Modulate cMet Expression and Signaling and Promote InlB-Mediated Listeria monocytogenes Infection of HeLa Cells.

The host cytoskeleton is a major target for bacterial pathogens during infection. In particular, pathogens usurp the actin cytoskeleton function to strongly adhere to the host cell surface, to induce plasma membrane remodeling allowing invasion and to spread from cell to cell and disseminate to the whole organism. Keratins are cytoskeletal proteins that are the major components of intermediate filaments in epithelial cells however, their role in bacterial infection has been disregarded. Here we investigate the role of the major epithelial keratins, keratins 8 and 18 (K8 and K18), in the cellular infection by Listeria monocytogenes. We found that K8 and K18 are required for successful InlB/cMet-dependent L. monocytogenes infection, but are dispensable for InlA/E-cadherin-mediated invasion. Both K8 and K18 accumulate at InlB-mediated internalization sites following actin recruitment and modulate actin dynamics at those sites. We also reveal the key role of K8 and K18 in HGF-induced signaling which occurs downstream the activation of cMet. Strikingly, we show here that K18, and at a less extent K8, controls the expression of cMet and other surface receptors such TfR and integrin β1, by promoting the stability of their corresponding transcripts. Together, our results reveal novel functions for major epithelial keratins in the modulation of actin dynamics at the bacterial entry sites and in the control of surface receptors mRNA stability and expression.

Keratin 8/18 regulation of insulin receptor signaling and trafficking in hepatocytes through a concerted phosphoinositide-dependent Akt and Rab5 modulation.

Keratins (Ks) are epithelial cell intermediate filament (IF) proteins that are expressed as pairs in a differentiation-regulated manner. Hepatocyte IFs are made only of K8/K18 pairs, which means that a K8 loss in K8-null mice leads to degradation of K18. Functionally, there is accumulating evidence that IFs contribute to signaling platforms. Here, we investigate the role of K8/K18 IFs in the regulation of insulin receptor (IR) signaling and trafficking in hepatocytes. We find that the IR substrate 1 (IRS1)/PI3K/Akt signaling cascade-downstream of IR-displays prolonged activation in K8-null compared with wild-type hepatocytes. Assessment of the Akt/mammalian target of rapamycin complex 1-mediated feedback loop to IRS1/PI3K, in the absence or presence of drug inhibitors, further supports a preferential K8/K18 IF intervention at the surface membrane. In K8-null hepatocytes, IR trafficking vesicles that are labeled by Rab5/EEA1/phosphatidylinositol 3-phosphate accumulate at a juxtanuclear region via a microtubule-dependent process. Moreover, interference with phosphatidylinositol 4,5-biphosphate signaling aggravates IR/Rab5 accumulation. Overall, results uncover K8/K18 IF regulation of IR signaling via a concerted modulation of phosphatidylinositol 4,5-biphosphate-dependent IRS1/PI3K/Akt signaling and Rab5/phosphatidylinositol 3-phosphate/microtubule trafficking in hepatocytes.-Roux, A., Loranger, A., Lavoie, J. N., Marceau, N. Keratin 8/18 regulation of insulin receptor signaling and trafficking in hepatocytes through a concerted phosphoinositide-dependent Akt and Rab5 modulation.

Keratin impact on PKCδ- and ASMase-mediated regulation of hepatocyte lipid raft size - implication for FasR-associated apoptosis.

Keratins are epithelial cell intermediate filament (IF) proteins that are expressed as pairs in a cell-differentiation-regulated manner. Hepatocytes express the keratin 8 and 18 pair (denoted K8/K18) of IFs, and a loss of K8 or K18, as in K8-null mice, leads to degradation of the keratin partner. We have previously reported that a K8/K18 loss in hepatocytes leads to altered cell surface lipid raft distribution and more efficient Fas receptor (FasR, also known as TNFRSF6)-mediated apoptosis. We demonstrate here that the absence of K8 or transgenic expression of the K8 G62C mutant in mouse hepatocytes reduces lipid raft size. Mechanistically, we find that the lipid raft size is dependent on acid sphingomyelinase (ASMase, also known as SMPD1) enzyme activity, which is reduced in absence of K8/K18. Notably, the reduction of ASMase activity appears to be caused by a less efficient redistribution of surface membrane PKCδ toward lysosomes. Moreover, we delineate the lipid raft volume range that is required for an optimal FasR-mediated apoptosis. Hence, K8/K18-dependent PKCδ- and ASMase-mediated modulation of lipid raft size can explain the more prominent FasR-mediated signaling resulting from K8/K18 loss. The fine-tuning of ASMase-mediated regulation of lipid rafts might provide a therapeutic target for death-receptor-related liver diseases.

Keratin 23 represents a novel liver injury marker reflecting the severity of ductular reaction

Keratins (K) are the intermediate filaments of epithelial cells and constitute established diagnostic tools. In the liver, K7/K19 expression is restricted to hepatic progenitor cells (HPCs) and biliary epithelial cells (BECs). Consequently, K7/K19 represent a widely used marker of the regenerative liver response termed ductular reaction (DR) that consists of activated BECs and HPCs. Methods: Since K23 is a largely unknown keratin family member, we analysed its expression and localization in selected human liver disorders and mouse liver injury models using custom-made antibodies. Serum K23 levels were measured via dot blot analysis. K23 regulation in response to IL1b was studied in hepatocellular and bile duct carcinoma cell lines. Results: In untreated mice, K23 was found in biliary epithelia but not hepatocytes. It was (together with K7/K19) markedly up-regulated in three different DR/cholestatic injury models, i.e. MDR2 knockouts, animals treated with 3,5-diethoxycarbonyl-1,4-dihydrocollidine or subjected to bile duct ligation. No changes in K23 levels were seen in hepatocellular injury models such as partial hepatectomy or carbon tetrachloride-induced fibrogenesis. K23 levels correlated with the DR marker Fn14 and immunofluorescence staining showed a distinct but not perfect co-localization with K7/K19. In cell culture, K23 expression was upregulated after IL1b treatment. In humans, K23 levels were moderately up-regulated in active HCV (˜3 times) and ALD (˜10 times). K23 expression was higher in patients with more prominent inflammation/fibrosis. A dramatic increase (> 200 times) was observed in patients with ALF and end-stage PBC. K23 serum levels were significantly higher in patients with alcoholic liver cirrhosis compared to control subjects. In conclusion, K23 represents a novel, stress inducible DR marker and its levels correlate with the severity of the liver disease. Given its release into the serum and its rather specific expression pattern, it may represent an attractive non-invasive marker of liver injury/regeneration.

Cytokeratin 18 for chemotherapy efficacy in gastric cancer

Cytokeratin 18 (CK18) is the major component of intermediate filaments in epithelial cells and released into the blood in either intact (M65) or caspase-cleaved forms (M30) during apoptotic and necrotic cell death. M30 and M65 are relatively described as novel sandwich ELISA assays that determine different circulating forms of the protein CK18 in either plasma or serum and are proposed to be surrogate endpoints of different forms of cell death. Serum M65 and M30 levels have shown to be elevated in patients with different types of carcinoma. The measurement of M30 or M65 values from epithelial-derived tumors could be a simple, noninvasive way to monitor or predict tumor progression and prognosis. Recently, predictive significance of the increase in the serum M30 and M65 values after chemotherapy in patients advanced nonsmall cell lung cancer (NSCLC) and gastric cancer have been evaluated. It shown that increased serum M65 levels, 48 hours after chemotherapy, could be predicted tumor response in advanced-gastric cancer patients. Although these assays may be useful for evaluating treatment effects and survival in patients with gastric cancer, their importance should be tested after multiple chemotherapy sessions in larger prospective studies with long follow-up time. In this review, prognostic and predictive significance of CK18 for advanced-gastric cancer are summarized in the light of recent advances.

Abstract LB-045: Detection of keratin fusions in oral squamous cell carcinoma

Abstract Keratin cytoskeleton proteins form intermediate filaments in epithelial cells to regulate cell shape, mobility, membrane trafficking and cellular signaling. Although keratin-6 (K6) and -14 (K14) are highly expressed in certain squamous cell carcinomas and have been suggested as tumor markers, molecular mechanisms of how keratins contribute to cancer development still remain elusive. Here, we demonstrated novel K6-K14 chimeras in oral squamous cell carcinomas (OSCCs) by pair-ended transcriptome sequencing and subsequent validation by fluorescence in situ hybridization and junction site mapping. Two unique fusion types (type-1 and type-2) were identified with a total of 23 in-frame fusion variants verified in OSCCs. Clinical screening confirmed high detection rate of K6-K14 fusions in tumor samples: 33% for type-1 and 25% for type-2. Notably, K6-K14 fusions could be only detected in tumor lesions at late carcinoma stage, but not the ones at early stages, suggesting potential benefits of K6-K14 fusions in promoting aggressive tumors. Functional domain analyses revealed a potent role involved in EMT and metastasis. Citation Format: Jim Jinn-Chyuan Sheu. Detection of keratin fusions in oral squamous cell carcinoma. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr LB-045. doi:10.1158/1538-7445.AM2015-LB-045

Group B Streptococcal Infection of the Choriodecidua Induces Dysfunction of the Cytokeratin Network in Amniotic Epithelium: A Pathway to Membrane Weakening

Early events leading to intrauterine infection remain poorly defined, but may hold the key to preventing preterm delivery. To determine molecular pathways within fetal membranes (chorioamnion) associated with early choriodecidual infection that may progress to preterm premature rupture of membranes (PPROM), we examined the effects of a Group B Streptococcus (GBS) choriodecidual infection on chorioamnion in a nonhuman primate model. Ten chronically catheterized pregnant monkeys (Macaca nemestrina) at 118–125 days gestation (term = 172 days) received choriodecidual inoculation of either GBS (n = 5) or saline (n = 5). Cesarean section was performed in the first week after GBS or saline inoculation. RNA extracted from chorioamnion (inoculation site) was profiled by microarray. Single gene, Gene Set, and Ingenuity Pathway Analysis results were validated using qRT-PCR (chorioamnion), Luminex (amniotic fluid, AF), immunohistochemistry, and transmission electron microscopy (TEM). Despite uterine quiescence in most cases, significant elevations of AF cytokines (TNF-α, IL-8, IL-1β, IL-6) were detected in GBS versus controls (p<0.05). Choriodecidual infection resolved by the time of cesarean section in 3 of 5 cases and GBS was undetectable by culture and PCR in the AF. A total of 331 genes were differentially expressed (>2-fold change, p<0.05). Remarkably, GBS exposure was associated with significantly downregulated expression of multiple cytokeratin (CK) and other cytoskeletal genes critical for maintenance of tissue tensile strength. Immunofluorescence revealed highly significant changes in the CK network within amniocytes with dense CK aggregates and retraction from the cell periphery (all p = 0.006). In human pregnancies affected by PPROM, there was further evidence of CK network retraction with significantly shorter amniocyte foot processes (p = 0.002). These results suggest early choriodecidual infection results in decreased cellular membrane integrity and tensile strength via dysfunction of CK networks. Downregulation of CK expression and perturbations in the amniotic epithelial cell intermediate filament network occur after GBS choriodecidual infection, which may contribute to PPROM.

X-ray nano-diffraction on cytoskeletal networks

The nano-scale structure of cytoskeletal biopolymers as well as sophisticated superstructures determine the versatile cellular shapes and specific mechanical properties. One example is keratin intermediate filaments in epithelial cells, which form thick bundles that can further organize in a cross-linked network. To study the native structure of keratin bundles in whole cells, high-resolution techniques are required, which do at the same time achieve high penetration depths. We employ scanning x-ray diffraction using a nano-focused x-ray beam to study the structure of keratin in freeze-dried eukaryotic cells. By scanning the sample through the beam we obtain x-ray dark-field images with a resolution of the order of the beam size, which clearly show the keratin network. Each individual diffraction pattern is further analyzed to yield insight into the local sample structure, which allows us to determine the local structure orientation. Due to the small beam size we access the structure in a small sample volume without performing the ensemble average over one complete cell.

Keratin 8/18 Regulation of Cell Stiffness-Extracellular Matrix Interplay through Modulation of Rho-Mediated Actin Cytoskeleton Dynamics

Cell mechanical activity generated from the interplay between the extracellular matrix (ECM) and the actin cytoskeleton is essential for the regulation of cell adhesion, spreading and migration during normal and cancer development. Keratins are the intermediate filament (IF) proteins of epithelial cells, expressed as pairs in a lineage/differentiation manner. Hepatic epithelial cell IFs are made solely of keratins 8/18 (K8/K18), hallmarks of all simple epithelia. Notably, our recent work on these epithelial cells has revealed a key regulatory function for K8/K18 IFs in adhesion/migration, through modulation of integrin interactions with ECM, actin adaptors and signaling molecules at focal adhesions. Here, using K8-knockdown rat H4 hepatoma cells and their K8/K18-containing counterparts seeded on fibronectin-coated substrata of different rigidities, we show that the K8/K18 IF-lacking cells lose their ability to spread and exhibit an altered actin fiber organization, upon seeding on a low-rigidity substratum. We also demonstrate a concomitant reduction in local cell stiffness at focal adhesions generated by fibronectin-coated microbeads attached to the dorsal cell surface. In addition, we find that this K8/K18 IF modulation of cell stiffness and actin fiber organization occurs through RhoA-ROCK signaling. Together, the results uncover a K8/K18 IF contribution to the cell stiffness-ECM rigidity interplay through a modulation of Rho-dependent actin organization and dynamics in simple epithelial cells.

Immunohistochemical Localization of Cytokeratins in the Junctional Region of Ectoderm and Endoderm

Although tridermic species have two junctional regions of ectoderm and endoderm between their epidermis and digestive tract, we actually know little about these particular boundaries. Cytokeratins are the major intermediate filaments of epithelial cells and show a high degree of tissue specificity. Therefore, to characterize the epithelial cells in the junctional region of ectoderm and endoderm, we immunohistochemically examined the localization of cytokeratins 5, 7/17, 14, 18, Sox17, and alpha-fetoprotein (AFP) in the oropharyngeal and anorectal regions during the mouse gastrulation process. At embryonic day (E) 9.5, cytokeratins 5, 7/17, 14, and 18 were detected in all epithelial cells of the oropharyngeal region. At E12.5, cytokeratin 5-positive cells were not observed in the middle area of the oral cavity; however, the immunoreactivity was strong in the anterior and posterior areas. The immunoreaction of cytokeratins 18 was seen only in the middle and posterior areas of the oral mucosa. Cytokeratins 7/17 and 14 were localized in all areas of the oropharyngeal region. Sox17 and AFP, which are endodermal markers, were detected in the middle and posterior areas of the oral mucosa, but not in the anterior area. Moreover, this same localization pattern of cytokeratins also existed in the anorectal region of the E12.5 embryo, suggesting that the localization of cytokeratins and endodermal markers might give an implication for the boundary between ectoderm and endoderm. These results also suggest that these cytokeratins are useful molecules for monitoring the epithelial cell differentiation in the junctional region of the germ layers.

GCP6 Binds to Intermediate Filaments: A Novel Function of Keratins in the Organization of Microtubules in Epithelial Cells

In simple epithelial cells, attachment of microtubule-organizing centers (MTOCs) to intermediate filaments (IFs) enables their localization to the apical domain. It is released by cyclin-dependent kinase (Cdk)1 phosphorylation. Here, we identified a component of the gamma-tubulin ring complex, gamma-tubulin complex protein (GCP)6, as a keratin partner in yeast two-hybrid assays. This was validated by binding in vitro of both purified full-length HIS-tagged GCP6 and a GCP6(1397-1819) fragment to keratins, and pull-down with native IFs. Keratin binding was blocked by Cdk1-mediated phosphorylation of GCP6. GCP6 was apical in normal enterocytes but diffuse in K8-null cells. GCP6 knockdown with short hairpin RNAs (shRNAs) in CACO-2 cells resulted in gamma-tubulin signal scattered throughout the cytoplasm, microtubules (MTs) in the perinuclear and basal regions, and microtubule-nucleating activity localized deep in the cytoplasm. Expression of a small fragment GCP6(1397-1513) that competes binding to keratins in vitro displaced gamma-tubulin from the cytoskeleton and resulted in depolarization of gamma-tubulin and changes in the distribution of microtubules and microtubule nucleation sites. Expression of a full-length S1397D mutant in the Cdk1 phosphorylation site delocalized centrosomes. We conclude that GCP6 participates in the attachment of MTOCs to IFs in epithelial cells and is among the factors that determine the peculiar architecture of microtubules in polarized epithelia.

Cytokeratin expression in pseudoepitheliomatous hyperplasia of oral paracoccidioidomycosis

Paracoccidioidomycosis (Pmycosis) is one the most prevalent deep systemic mycoses in Latin America. It is characterized by granulomatous inflammation and pseudoepitheliomatous hyperplasia. Cytokeratins (CKs) are a group of intermediate filaments of epithelial cells and their expression varies according to the epithelium type, differentiation and pathological processes. This study describes cytokeratin expression as examined by immunohistochemistry, in 28 cases of oral Pmycosis involving the buccal mucosa, lip, gingiva and hard palate. Expression of CKs in the basal layer of the epithelium in pseudoepitheliomatous hyperplasia of Pmycosis was similar to that in normal oral mucosa (NOM), but in Pmycosis CK1 and CK10 were not expressed in the spinous and superficial layers of the lip, gingiva or hard palate, and, in the spinous and superficial layers of the lip and buccal mucosa, CK14 was positive in contrast to NOM where it was negative. In Pmycosis, CK6 was more frequently expressed in the spinous layer of the lip, gingiva and hard palate, but nevertheless CK16 expression was decreased in the spinous and superficial layers of the gingiva and hard palate. We conclude that pseudoepitheliomatous hyperplasia in oral Pmycosis shows a different pattern of CK expression, particularly CKs 1, 10 and 14, compared with NOM.

Keratinocyte Heal Thyself: A New Form of “Natural Gene Therapy”

In little more than a decade, the biologic importance and clinical significance of keratin intermediate filaments in epithelial cells has become very evident. Indeed, several autosomal dominant (and less commonly, recessive) human diseases involving mutated keratin genes have been described (Irvine and McLean, 1999;Smith, 2003). From such studies, the accumulating mutation databases provide useful clinical information for predicting prognosis, optimizing genetic counseling, and, if clinically and ethically appropriate, undertaking DNA-based prenatal diagnosis. Delineation of the exact nature of the pathogenic mutations also provides a basis for the development of suitable and perhaps optimal approaches to gene therapy.

Detection of tumor circulating cells by cytokeratin-20 in the blood of patients with granulosa cell tumors.

Cytokeratins (CKs) are constituents of the intermediate filaments of epithelial cells which are expressed in various combinations, depending on the epithelial type and the degree of differentiation. Using the reverse transcriptase-polymerase chain reaction (RT-PCR) technique, we recently demonstrated that cytokeratin-20 (CK-20), the most recently discovered cytokeratin, is expressed in endometrial carcinoma tumors, in blood, and in lymph nodes with micrometastases of patients treated for endometrial carcinomas. However, CK-20 expression could not be demonstrated in the endometrium of patients with benign diseases, in peripheral blood, in lymph nodes of healthy subjects, or in normal blood cells. The aim of this study was to examine whether CK-20 expression in blood can be used as a biomarker for the detection of the dissemination of malignant cells in patients treated for granulosa cell tumors (GCTs). In this study, we used RT-PCR to determine the expression of CK-20 in the following groups: (i) blood of patients (n = 14) treated for GCTs, (ii) GCT samples (n = 4); (iii) lymph nodes (n = 2) of patients treated for GCTs; (iv) blood from subjects with benign sex-cord-stromal tumors (n = 2); (v) normal ovaries of two menstruating women (n = 4); (vi) tumor specimens of epithelial ovarian carcinomas (EOCs) (n = 14); and (vii) blood samples (n = 18) and lymph nodes (n = 11) of healthy women. In Group I, CK-20 was positive in the blood in 86% (12/14) of the patients. In Group II, CK-20 was positive in 100% (4/4) of the GCT samples. In Group III, CK-20 was positive in 100% (2/2) of the lymph nodes examined. In Groups IV and V, CK-20 was negative in 100% (2/2) of the blood samples and in the normal ovarian specimens (4/4) that were examined. In Group VI, CK-20 was positive in 14% (2/14) of nonmucinous EOCs. In Group VII, CK-20 was negative in 100% (18/18) of blood and in (11/11) lymph node specimens (specificity 100%). These results indicate that RT-PCR of CK-20, because of its high sensitivity and specificity, is a potential biomarker for detecting metastases in blood and in micrometastases in lymph nodes of patients treated for GCTs.

Detection of Tumor Circulating Cells by Cytokeratin 20 in the Blood of Patients with Endometrial Carcinoma

Background. Cytokeratins are constituents of the intermediate filaments of epithelial cells which are expressed in various combinations depending on the epithelial type and the degree of differentiation. Using the reverse transcriptase-polymerase chain reaction technique (RT-PCR) we recently demonstrated that: (1) Cytokertin 20—the most recent discovered cytokeratin—is expressed in endometrial carcinoma tumors but not in the endometrium of patients with benign diseases, and (2) CK-20 is not expressed in blood cells. The aim of this study is to examine whether CK-20 expression in blood can be used as a biomarker for the detection of the dissemination of malignant cells in patients treated for endometrial carcinoma.Methods. In the present study, we have used RT-PCR to determine the expression of CK-20 in the peripheral blood of the following groups: (1) preop new diagnosed patients (n = 20), (2) patients with no clinical evidence of disease following completion of definitive treatment (n = 33; 17 at low risk; 16 at high risk), (3) patients with recurrent disease (n = 6), and (4) a control group of healthy subjects (n = 16). RNA was extracted from cell pellets and analysed by RT-PCR using primers for CK-20.Results. Of the 20 patients of the first group 7 (35%) were CK-20 positive. Of the 33 patients of the second group 17 (51%) were CK-20 positive. Subdivision of this group showed that 9 of 17 (53%) were positive in the low-risk subgroup, and 8 of 16 (50%) were positive in the high-risk subgroup. All 6 patients with recurrent disease were positive, and all subjects in the control group were negative.Conclusion. These results indicate that RT-PCR of CK-20, because of its high sensitivity, is a potential biomarker for detecting metastasis in blood samples of patients with endometrial carcinoma.

Expression of cytokeratin 20 in the blood of patients with disseminated carcinoma of the pancreas, colon, stomach, and lung

Cytokeratins are constituents of the intermediate filaments of epithelial cells that are expressed in various combinations depending on the epithelial type and the degree of differentiation. The recently identified cytokeratin 20 (CK-20) was found to be expressed in colonic, gastric, and pancreatic carcinoma tumor tissues. A low rate of incidence of expression of CK-20 was found in tumor tissue from lung carcinoma but no expression was found in blood even with the sensitive reverse transcriptase-polymerase chain reaction (RT-PCR) method. The objective of the current study was to examine whether CK-20 expression in the blood can be used as a biomarker for the detection of dissemination in patients with carcinoma of the colon, stomach, and pancreas. In the current study, RT-PCR was used to determine the expression of CK-20 in the blood cells from patients with metastatic colon carcinoma (n = 22), metastatic pancreatic carcinoma (n = 28), metastatic gastric carcinoma (n = 18), metastatic lung carcinoma (n = 13), no metastatic colon carcinoma (n = 13) and no known malignant diseases (n = 22). RNA was extracted from cell pellets and analyzed by RT-PCR using primers for CK-20. In the group of 22 patients with metastatic colon carcinoma, 14 were found to be CK-20 positive (sensitivity of 63.6% and specificity of 92.3%), 22 of the 28 pancreatic carcinoma patients showed positive CK-20 expression, and 12 of 18 patients with gastric carcinoma showed positive CK-20 expression. All patients with metastatic lung carcinoma except 1 were negative (12 of 13 patients), and 12 of 13 patients with colonic carcinoma with no known metastases also were negative. Negative CK-20 results were obtained in all 22 patients with no known malignant diseases. The results of the current study indicate that because of its high sensitivity, RT-PCR of CK-20 is a potential biomarker for detecting metastases in blood samples from patients with carcinoma of the colon, stomach, and pancreas.

CYTOKERATIN 20: A NEW MARKER FOR EARLY DETECTION OF BLADDER CELL CARCINOMA

Purpose Cytokeratins are constituents of the intermediate filaments of epithelial cells in which they are expressed in various combinations depending on epithelial type and degree of differentiation. Of the 20 known cytokeratins, cytokeratin 19 is expressed in normal urothelium cells, whereas the recently identified cytokeratin 20 (CK-20) is expressed in urothelial carcinoma but not normal urothelium cells. We examine whether CK-20 expression can be used as a bladder tumor marker for transitional cell carcinoma in cells isolated from urine. Materials and Methods The reverse transcriptase polymerase chain reaction method was used to determine expression of CK-20 in cells separated from urine of patients with bladder carcinoma. Cells were obtained from urine of 192 patients stratified into 3 groups of 21 healthy young volunteers without a history of transitional cell carcinoma, 27 with a negative bladder biopsy for transitional cell carcinoma and 144 with bladder transitional cell carcinoma. The parameters were tumor stage and grade, tumor size, number of tumors, urinary cytology and CK-20. Results CK-20 amplification band (370 base pairs) was obtained with messenger ribonucleic acid extracted from transitional cell carcinoma cells of bladder tumor. CK-20 in the urine samples of the control group was negative (no false-positive results, specificity 100%). Among the 27 patients with pTo disease CK-20 was negative in 20 (specificity 74.1%). In the 7 patients with positive CK-20 histology showed chronic inflammation in 2, atypical hyperplasia in 3 and metaplasia in 1. In 1 patient who had a known history of transitional cell carcinoma the urothelium was normal. Among 144 patients with bladder transitional cell carcinoma CK-20 was positive in 131. Sensitivity of the method was much higher than urinary cytology (91 versus 56.3%, p <0.0001). We demonstrated no correlation between CK-20 and tumor grade. Conclusions Our results indicate that CK-20 is a potential marker for bladder cancer. The noninvasive detection method assesses urothelial cells from the voided urine specimen using reverse transcriptase-polymerase chain reaction. The CK-20 marker was significantly more sensitive than urinary cytology.