Activated leukocyte cell adhesion molecule (ALCAM) and annexin II are involved in the metastatic progression of tumor cells after chemotherapy with Adriamycin

The Clinical and Theranostic Values of Activated Leukocyte Cell Adhesion Molecule (ALCAM)/CD166 in Human Solid Cancers

Simple Summary

ALCAM (activated leukocyte cell adhesion molecule) is an important regulator in human cancers, particularly solid tumours. Its expression in cancer tissues has prognostic values depending on cancer types and is also linked to distant metastases. A truncated form, soluble form of ALCAM (sALCAM) in circulation has been suggested to be a prognostic indicator and a potential therapeutic tool. This article summarises recent findings and progress in ALCAM and its involvement in cancer, with a primary focus on its clinical connections and therapeutic values.

Abstract

Activated leukocyte cell adhesion molecule (ALCAM), also known as CD166, is a cell adhesion protein that is found in multiple cell types. ALCAM has multiple and diverse roles in various physiological and pathological conditions, including inflammation and cancer. There has been compelling evidence of ALCAM’s prognostic value in solid cancers, indicating that it is a potential therapeutic target. The present article overviews the recent findings and progress in ALCAM and its involvement in cancer, with a primary focus on its clinical connections in cancer and therapeutic values.

MiR-148a and miR-152 reduce tamoxifen resistance in ER+ breast cancer via downregulating ALCAM

Activated leukocyte cell adhesion molecule (ALCAM), also called CD166 is a 105-kDa transmembrane glycoprotein of the immunoglobin superfamily. In this study, we studied the association between ALCAM expression and tamoxifen resistance in ER + breast cancer and further investigated how ALCAM is regulated in the cancer cells. IHC staining data showed that the tumor tissues from non-responders (N = 20) generally had significantly stronger ALCAM staining than that from tamoxifen responders (N = 16). In vitro cell assay also confirmed ALCAM upregulation in tamoxifen resistant (TamR) MCF-7 cells than in tamoxifen sensitive (TamS) MCF-7 cells. ALCAM overexpression significantly alleviated 4-Hydroxytestosterone (4-OHT) induced cell viability inhibition and cell apoptosis in TamS MCF-7 cells, while ALCAM knockdown remarkably enhanced 4-OHT induced cell viability inhibition and cell apoptosis in TamR MCF-7 cells. Demethylation reagent treatment significantly restored miR-148a and miR-152 expression in TamR MCF-7 cells. MiR-148a and miR-152 can directly target ALCAM 3'UTR and decrease ALCAM expression. MiR-148a overexpression had similar effect as ALCAM siRNA on enhancing 4-OHT induced cell viability inhibition and cell apoptosis in TamR MCF-7 cells. MiR-152 overexpression alone caused growth inhibition and increased cell apoptosis in TamR MCF-7 cells. It also enhanced the effect of 4-OHT. Simultaneous inhibition of miR-148a and miR-152 significantly protected TamS MCF-7 cells from 4-OHT induced cell viability inhibition and cell apoptosis. Based on these findings, we infer that MiR-148a and miR-152 can sensitize TamR MCF-7 cells to tamoxifen at least via downregulating ALCAM.

Cell Adhesion Molecules and Ubiquitination-Functions and Significance

Cell adhesion molecules of the immunoglobulin (Ig) superfamily represent the biggest group of cell adhesion molecules. They have been analyzed since approximately 40 years ago and most of them have been shown to play a role in tumor progression and in the nervous system. All members of the Ig superfamily are intensively posttranslationally modified. However, many aspects of their cellular functions are not yet known. Since a few years ago it is known that some of the Ig superfamily members are modified by ubiquitin. Ubiquitination has classically been described as a proteasomal degradation signal but during the last years it became obvious that it can regulate many other processes including internalization of cell surface molecules and lysosomal sorting. The purpose of this review is to summarize the current knowledge about the ubiquitination of cell adhesion molecules of the Ig superfamily and to discuss its potential physiological roles in tumorigenesis and in the nervous system.

Effect of shRNA mediated down-regulation of Annexin A2 on biological behavior of human lung adencarcinoma cells A549

In the previous study, we found that Annexin A2 was significantly up-regulated in lung cancer and could induce related-antigen in lung cancer patients' serum. To further study the function of Annexin A2, the short hairpin RNA plasmid targeting Annexin A2 was constructed in vitro and transfected into human lung adencarcinoma A549 cells. Knocking down Annexin A2 expression by shRNA, the mRNA level of Annexin A2 was investigated by semi-quantitative RT-PCR. The expression of Annexin A2 protein was examined by Western Blotting and Immuocytochemistry. MTT assay and Transwell chamber model were used to evaluate proliferation and invasion of A549 cells in vitro. The concentration of matrix metalloproteinase-2 (MMP-2) and cathepsin B (CB) in the supernatant was evaluated by ELISA. At 48 h after transfection, the expression of Annexin A2 mRNA and protein was down-regulated significantly, respectively (p < 0.05).The proliferation and invasion capability of A549 cells also decreased significantly (p < 0.05). The concentration of MMP-2 and CB was down-regulated obviously, respectively (p < 0.05). This study implies that Annexin A2 might play an important role in the progression and invasion of human lung cancer cells, and could promote progression of lung cancer by regulating the expression of MMP-2 and CB.

Clinical implications of activated leukocyte cell adhesion molecule expression in breast cancer

In the study, we enrolled 150 breast cancer cases to investigate the expression status of activated leukocyte cell adhesion molecule (ALCAM), and the relationships between ALCAM expression and clinical-pathological characteristics and prognosis of breast cancer. It was observed that ALCAM was expressed at higher levels in breast cancer tissue compared to levels observed for tumor-adjacent tissue. Compared to cancers with low membranous ALCAM expression, cancers with high membranous ALCAM expression were prone to lymph node metastasis (χ2=15.910, P=0.010) and metastasis in general (χ2=5.211, P=0.029). High cytoplasmic ALCAM expression was noticeably correlated with local recurrence (χ2=7.379, P=0.012), especially for short-term recurrence (interval<2 years) (χ2=5.562, P=0.037), while not associated to long-term local recurrence (interval>2 years). The content of ALCAM protein is closely associated with the expression of estrogen receptor (ER) (P=0.024). The disease-free survival of patients with high cytoplasmic ALCAM expression was significantly shorter compared to the cases with low cytoplasmic ALCAM expression (P=0.036). In conclusion, ALCAM expressed at high levels in breast cancer. High membranous expression of ALCAM probably resulted in weakened adherent ability and metastasis. In addition, high cytoplasmic ALCAM expression strengthened invasive ability of malignant cells and then promoted tumor development.

A proteomic approach to study parathyroid glands

Parathyroid tumours are heterogeneous and in some cases the diagnosis may be difficult using histological features. In this study we used a two-dimensional electrophoresis (2D)/mass spectrometry (MS)-based approach to examine the global changes of parathyroid adenoma tissues protein profile compared to the parathyroid normal tissues. Validation of protein expression was performed by immunoblotting using specific antibodies. Ingenuity software was used to identify the biological processes to which these proteins belong and to construct a potential network. A total of 30 proteins were found to be differentially expressed, of which 22 resulted in being over-expressed. Proteins identified by 2D/MS/MS proteomics were classified into functional categories and a major change (≥ 2-fold) in terms of expression was found in proteins involved in response to biotic stimuli, cell organization and signal transduction. After Ingenuity analysis, 14-3-3 ζ/δ appears to be a key protein in the network of parathyroid adenoma, where it is linked to other proteins such as annexin A2, B box and SPRY domain-containing protein (BSPRY), p53 and epidermal growth factor receptor (EGFR). Our results suggest that the proteomic approach was able to differentiate the protein profiles of normal parathyroid and parathyroid adenoma and identify a panel of proteins which are differentially expressed. The functional role of these proteins in the network of intracellular pathways is discussed.

Increased expression of ALCAM/CD166 in pancreatic cancer is an independent prognostic marker for poor survival and early tumour relapse

Background:

ALCAM (activated leucocyte cell adhesion molecule, synonym CD166) is a cell adhesion molecule, which belongs to the Ig superfamily. Disruption of the ALCAM-mediated adhesiveness by proteolytic sheddases such as ADAM17 has been suggested to have a relevant impact on tumour invasion. Although the expression of ALCAM is a valuable prognostic and predictive marker in several types of epithelial tumours, its role as a prognostic marker in pancreatic cancer has not yet been reported.

Methods:

In this study, paraffin-embedded samples of 97 patients with pancreatic cancer undergoing potentially curative resection were immunostained against ALCAM, ADAM17 and CK19. Expression of ALCAM and ADAM17 was semiquantitatively evaluated and correlated to clinical and histopathological parameters.

Results:

We could show that in normal pancreatic tissue, ALCAM is predominantly expressed at the cellular membrane, whereas in pancreatic tumour cells, it is mainly localised in the cytoplasm. In addition, univariate and multivariate analyses show that increased expression of ALCAM is an adverse prognostic factor for recurrence-free and overall survival. Overexpression of ADAM17 in pancreatic cancer, however, failed to be a significant prognostic marker and was not coexpressed with ALCAM.

Conclusions:

Our findings support the hypothesis that the disruption of ALCAM-mediated adhesiveness is a relevant step in pancreatic cancer progression. Moreover, ALCAM overexpression is a relevant independent prognostic marker for poor survival and early tumour relapse in pancreatic cancer.

The role of annexins in tumour development and progression

The annexins are a super-family of closely related calcium and membrane-binding proteins. They have a diverse range of cellular functions that include vesicle trafficking, cell division, apoptosis, calcium signalling and growth regulation. Many studies have shown the annexins to be among the genes whose expression are consistently differentially altered in neoplasia. Some annexins show increased expression in specific types of tumours, while others show loss of expression. Mechanistic studies relating the changes in annexin expression to tumour cell function, particularly tumour invasion and metastasis, angiogenesis and drug resistance, are now also emerging. Changes in the expression of individual annexins are associated with particular types of tumour and hence the annexins may also be useful biomarkers in the clinic.

Interferon-gamma reduces cell surface expression of annexin 2 and suppresses the invasive capacity of prostate cancer cells

The effect of interferon-gamma (IFNgamma) treatment on cell surface protein expression was studied in the human prostate cancer cell line 1542CP3TX. IFNgamma increased both the number and abundance of proteins in membrane fractions. In contrast, the expression of annexin 2 and its binding partner p11 decreased by 4-fold after 24 h of exposure, with the remaining anx2(t) complexes localized to lipid rafts. Within the same time scale, IFNgamma reduced the abundance of the peripherally attached, anx2(t)-associated proteases procathepsin B and plasminogen. The invasive capacity of the cancer cells was reduced by treatment with IFNgamma or antibody to annexin 2 in 1542CP3TX cells, but not in LNCaP, an annexin 2-negative prostate cancer cell line. Expression of annexin 2 in LNCaP cells increased their invasiveness. IFNgamma induced calpain expression and activation and increased the phosphorylation and degradation of the calpain substrate ABCA1 in 1542CP3TX cancer cells. Surface expression of annexin 2 was reduced in cells treated with glyburide, an ABCA1 inhibitor, whereas inhibition of calpain abrogated IFNgamma-induced annexin 2 down-regulation and suppression of Matrigel invasion. The findings suggest annexin 2 externalization is coupled to lipid efflux in prostate epithelium and that IFNgamma induces down-regulation of the protease-binding anx2(t) scaffold at the cell surface and consequently acts to suppress invasiveness through calpain-mediated degradation of the lipid transporter ABCA1.

Expression of human NDRG2 by myeloid dendritic cells inhibits down-regulation of activated leukocyte cell adhesion molecule (ALCAM) and contributes to maintenance of T cell stimulatory activity

We reported previously that N-myc downstream-regulated gene 2 (NDRG2), a member of a new family of differentiation-related genes, is expressed specifically in dendritic cells (DC) differentiated from monocytes, CD34(+) progenitor cells, and the myelomonocytic leukemic cell line. In this study, we demonstrate that NDRG2 protein expression is detected, not only in in vitro-differentiated DC but also in primary DC from lymph nodes, thymus, and skin when anti-NDRG2 antibodies are used. As predicted from previous studies investigating the mRNA expression pattern of several types of cell lines, progenitor cells, and DC, NDRG2 protein was expressed strongly in DC. Its expression was detected at significant levels after differentiation from progenitor cells. RNA interference of NDRG2 demonstrated that activated leukocyte cell adhesion molecule (ALCAM) expression is down-regulated specifically in DC differentiated from NDRG2 small interfering RNA (siRNA)-transfected monocytes. This was consistent with our observation that U937 cells transfected with NDRG2 became resistant to the GM-CSF/IL-4-induced ALCAM reduction. Furthermore, DC, which had differentiated from NDRG2 siRNA-transfected monocytes, showed a reduced ability to induce T cell proliferation. Taken together, our results indicate that NDRG2 is able to preserve ALCAM expression during DC differentiation from monocytes under cytokine culture conditions and that its expression helps DC maintain costimulatory signals necessary for T cell stimulation.

Cytoplasmic overexpression of ALCAM is prognostic of disease progression in breast cancer

BACKGROUND

Activated leucocyte cell adhesion molecule (ALCAM, CD166) is a cell surface member of the immunoglobulin superfamily. ALCAM expression has prognostic relevance in prostate and colon cancer.

OBJECTIVE

To evaluate ALCAM protein expression in breast cancer by immunohistochemistry and to correlate expression levels with clinicopathological data.

METHODS

162 primary breast carcinomas with a mean clinical follow up time of 53 months were immunostained using a monoclonal ALCAM antibody. The staining was evaluated as an immunoreactive score (IRS) and grouped into low v high for both membranous and cytoplasmic staining.

RESULTS

Intraductal and invasive carcinomas showed a higher ALCAM expression (median IRS 4 and 6 respectively) than normal breast tissue (IRS 2). In univariate survival analyses a significant association of high cytoplasmic ALCAM expression with shortened patient disease-free survival (mean (SD) five year non-progression rate, 69.4 (4.6)% v 49.4 (11.1)%, p = 0.0142) was found. In multivariate analyses of disease-free survival times, high cytoplasmic ALCAM expression (relative risk (RR) = 2.086, p = 0.026) and nodal status (RR = 2.246, p = 0.035) were significantly associated with earlier disease progression, whereas tumour grading (RR = 1.6, p = 0.052) was of borderline significance.

CONCLUSIONS

The data suggest that strong cytoplasmic ALCAM expression in primary breast cancer, as detected by immunohistochemistry, might be a new marker for a more aggressive breast cancer biology.

MEMD/ALCAM: A Potential Marker for Tumor Invasion and Nodal Metastasis in Esophageal Squamous Cell Carcinoma

OBJECTIVE

The MEMD gene was reported to be overexpressed in human esophageal squamous cell carcinoma (ESCC), using differential display. The aim of this study was to determine the clinical significance of MEMD/ALCAM in esophageal tumorigenesis.

METHODS

Analysis of MEMD/ALCAM expression in esophageal tissues was carried out at protein and RNA level using immunohistochemistry and semiquantitative RT-PCR, respectively.

RESULTS

Increased MEMD/ALCAM expression was observed in 42/65 (65%) ESCCs (p = 0.000, odds ratio, OR = 3.665) and in 17/25 (68%) dysplasias (p = 0.000, OR = 4.248) compared to paired distant histologically normal esophageal tissues. Increased MEMD mRNAlevels were observed in ESCCs and dysplasias showing overexpression of MEMD/ALCAM protein. Interestingly, increased membranous MEMD/ALCAM expression was observed in dysplasias in comparison with ESCCs (p = 0.002, OR = 3.177). MEMD/ALCAM overexpression in ESCCs was associated with late clinical stage (p = 0.002, OR = 3.619), enhanced tumor invasiveness (p = 0.002, OR = 3.619), and nodal metastasis (p = 0.000, OR = 4.206).

CONCLUSION

To our knowledge, this is the first report showing MEMD expression at pre-malignant stage (dysplasia), suggesting that MEMD/ALCAM expression is an early event in the development of esophageal cancer. Furthermore, in ESCCs its correlation with late clinical stage, enhanced tumor invasiveness and nodal metastasis suggests an association with aggressive tumor behavior. Our data suggest that MEMD/ALCAM may serve as a potential marker for early diagnosis, tumor invasion and nodal metastasis in ESCCs.

Epidermal growth factor-induced hepatocellular carcinoma: gene expression profiles in precursor lesions, early stage and solitary tumours

Epidermal growth factor is an important mitogen for hepatocytes. Its overexpression promotes hepatocellular carcinogenesis. To identify the network of genes regulated through EGF, we investigated the liver transcriptome during various stages of hepatocarcinogenesis in EGF2B transgenic mice. Targeted overexpression of IgEGF induced distinct hepatocellular lesions and eventually solid tumours at the age of 6-8 months, as evidenced by histopathology. We used the murine MG U74Av2 oligonucleotide microarrays to identify transcript signatures in 12 tumours of small (n=5, pooled), medium (n=4) and large sizes (n=3), and compared the findings with three nontumorous transgenic livers and four control livers. Global gene expression analysis at successive stages of carcinogenesis revealed hallmarks linked to tumour size. A comparison of gene expression profiles of nontumorous transgenic liver versus control liver provided insight into the initial events predisposing liver cells to malignant transformation, and we found overexpression of c-fos, eps-15, TGIF, IGFBP1, Alcam, ets-2 and repression of Gas-1 as distinct events. Further, when gene expression profiles of small manifested tumours were compared with nontumorous transgenic liver, additional changes were obvious and included overexpression of junB, Id-1, minopontin, villin, claudin-7, RR M2, p34cdc2, cyclinD1 and cyclinB1 among others. These genes are therefore strongly associated with tumour formation. Our study provided new information on the tumour stage-dependent network of EGF-regulated genes, and we identified candidate genes linked to tumorigenes and progression of disease.

Internalization and recycling of ALCAM/CD166 detected by a fully human single-chain recombinant antibody

Activated leukocyte cell adhesion molecule (ALCAM/CD166), a member of the immunoglobulin superfamily with five extracellular immunoglobulin-like domains, promotes heterophilic (ALCAM-CD6) and homophilic (ALCAM-ALCAM) cell-cell interactions. Here we describe a fully human single-chain antibody fragment (scFv) directed to ALCAM/CD166. We selected the I/F8 scFv from a phage display library of human V-gene segments by cell panning and phage internalization into IGROV-I human ovary carcinoma cells. The I/F8 specificity was identified as ALCAM/CD166 by matrix-assisted laser desorption/ionisation time-of-flight (MALDI-TOF) peptide mass fingerprinting of the I/F8-immunoprecipitated protein. The I/F8 scFv reacts with the human, monkey and murine ALCAM/CD166 molecule, indicating that the recognized epitope is highly conserved. The I/F8 scFv completely abolished binding of both ALCAM/Fc and CD6/Fc soluble ligands, whereas it did not compete with the anti-ALCAM/CD166 murine monoclonal antibodies J4-81 and 3A6 and therefore recognizes a different epitope. Engagement through I/F8 scFv, 3A6 monoclonal antibody or CD6/Fc ligand induced ALCAM/CD166 internalization, with a kinetics slower than that of transferrin in the same cells. Newly internalized I/F8-ALCAM complexes colocalized with clathrin but not with caveolin and we demonstrated, using surface biotinylation and recycling assays, that endocytosed ALCAM/CD166 recycles back to the cell surface. Such an endocytic pathway allows the efficient delivery of an I/F8 scFv-saporin immunotoxin into tumor cells, as the conjugates are able to selectively kill cell lines expressing ALCAM/CD166. Altogether these data provide evidence of the suitability of the I/F8 scFv for further functional analysis of ALCAM/CD166 and intracellular delivery of effector moieties.

Neutrophils secrete MIP-1 beta after adhesion to laminin contained in basement membrane of blood vessels

We have recently demonstrated that granulocyte colony-stimulating factor (G-CSF) stimulated the production of epithelial-cell-derived-neutrophil attractant-78 (ENA-78) by neutrophils and that ENA-78 might promote the accumulation of neutrophils that had migrated from the intravascular space into inflammatory tissues. In this study, we examined whether other chemokines could be secreted by neutrophils that had accumulated after migrating from the intravascular space into the inflammatory tissues. We demonstrated that adhesion to laminin contained in the basement membrane and Matrigel, which is an artificial basement membrane model, induced macrophage inflammatory protein-1 beta (MIP-1 beta) in neutrophils and that MIP-1 beta secreted by neutrophils induced the chemotaxis of dendritic cells. These findings suggest that neutrophils transmigrating through the basement membrane are stimulated to secrete MIP-1 beta by the basement membrane, inducing the transmigration of dendritic cells from the intravascular space into inflammatory tissues. We propose that neutrophils intervene between innate immune response and specific immune response by secreting MIP-1 beta during the transmigration through the basement membrane.

ALCAM/CD166 is overexpressed in colorectal carcinoma and correlates with shortened patient survival

BACKGROUND

Activated leucocyte cell adhesion molecule (ALCAM) has been implicated in tumorigenesis and tumour progression of malignant melanoma and prostate cancer.

AIMS

To clarify the expression patterns of ALCAM in colon cancer and to correlate these with clinicopathological parameters, including patient survival.

METHODS

One hundred and eleven colorectal carcinomas were immunostained for ALCAM (clone MOG/07) using a standard detection system. Cytoplasmic and membranous immunoreactivity were scored semiquantitatively. Fisher's exact test, chi2 test for trends, Kaplan-Meier analysis, and Cox's regression were applied.

RESULTS

In colorectal cancer, 58.6% and 30.6% of cases showed strong cytoplasmic and membranous expression of ALCAM, respectively. No significant correlation with patient age, tumour grade, stage, or nodal status was apparent. In survival analyses, membranous ALCAM expression correlated significantly (Cox's regression, p=0.028; relative risk, 2.3) with shortened patient survival.

CONCLUSIONS

ALCAM is frequently upregulated in colorectal cancer and is a new independent prognostic marker, underscoring the importance of ALCAM in tumour progression in this disease.

The RacGEF Tiam1 inhibits migration and invasion of metastatic melanoma via a novel adhesive mechanism

Rho-like GTPases such as RhoA, Rac1 and Cdc42 are key regulators of actin-dependent cell functions including cell morphology, adhesion and migration. Tiam1 (T lymphoma invasion and metastasis 1), a guanine nucleotide exchange factor that activates Rac, is an important regulator of cell shape and invasiveness in epithelial cells and fibroblasts. Overexpression of Tiam1 in metastatic melanoma cells converted the constitutive mesenchymal phenotype into an epithelial-like phenotype. This included the induction of stringent cell-cell contacts mediated by the Ig-like receptor ALCAM (activated leukocyte cell adhesion molecule) and actin redistribution to cell-cell junctions. This phenotypic switch was dependent on increased Rac but not Rho activity, and on the redistribution and adhesive function of ALCAM, whereas cadherins were not involved. Although cell proliferation was significantly enhanced, the gain of cell-cell junctions strongly counteracted cell motility and invasion as shown for two- and three-dimensional collagen assays as well as invasion into human skin reconstructs. The reverse transition from mesenchymal invasive to a resident epithelial-like phenotype implicates a role for Tiam1/Rac signaling in the control of cell-cell contacts through a novel ALCAM-mediated mechanism.

Increased expression and altered location of annexin IV in renal clear cell carcinoma: a possible role in tumour dissemination

The proteome of renal cell carcinoma and non-neoplastic kidney tissue was analysed from 12 patients by two-dimensional polyacrylamide gel electrophoresis to search for differentially expressed proteins in the tumour. Annexin IV was identified to be up-regulated in tumour cells. These patients and further 11 were characterized by RT-PCR. We found an increased amount of annexin IV mRNA. Immunohistochemical analysis revealed an altered localization of annexin IV in tumour cells. Additionally we demonstrate that over-expressed annexin IV promotes cell migration in a carcinoma model system. From these results above it seems possible that annexin IV plays an important role in the morphological diversification and dissemination of the clear cell renal cell carcinoma.

Expression, subcellular localization and phosphorylation status of annexins 1 and 5 in human pituitary adenomas and a growth hormone-secreting carcinoma

OBJECTIVE

Annexin 1 (ANXA1), a 37-kDa protein, plays an important role as a mediator of glucocorticoid action in the anterior pituitary gland and has been implicated in the processes of tumorigenesis in a number of other tissues. As a prelude to examining the potential role of ANXA1 in the pathophysiology of pituitary tumours, this study examined the expression, phosphorylation status and distribution of ANXA1 and the closely related protein, annexin 5 (ANXA5), in a series of pituitary adenomas and in two carcinomas.

PATIENTS AND DESIGN

Forty-two human pituitary adenomas were examined. Parallel studies were performed on normal pituitary tissue, obtained postmortem, a GH-secreting carcinoma and a grade 4 astrocytoma.

MEASUREMENTS

The tissue was processed for analysis of ANXA1 mRNA and protein expression by reverse transcriptase polymerase chain reaction (RT-PCR), Western blot analysis and immunogold electron-microscopic histochemistry. Parallel measures of ANXA5 mRNA and protein were also made.

RESULTS

ANXA1 mRNA and protein were detected in all but three adenomas studied; the protein was localized mainly, but not exclusively, to nonendocrine cells. ANXA5 expression was more variable and was contained within both endocrine and nonendocrine cells of these tumours. In comparison with the adenomas, the GH-secreting carcinoma showed abundant expression of both ANXA1 and ANXA5, with intense ANXA1 staining in some but not all tumour/endocrine cells. A serine-phosphorylated species of ANXA1 was detected in all pituitary tumours studied; by contrast, tyrosine-phosphorylated ANXA1 was detected in only four adenomas and in the GH carcinoma. ANXA1 and ANXA5 were also expressed in abundance in the astrocytoma.

CONCLUSIONS

The results demonstrate expression of both ANXA1 and ANXA5 in human pituitary tumours and thus raise the possibility that these proteins influence the growth and/or functional activity of the tumours.

Expression and regulation of NDRG2 (N-myc downstream regulated gene 2) during the differentiation of dendritic cells

We searched for genes with expressions specific to human monocyte-derived dendritic cells (DCs) using differential display reverse transcription-polymerase chain reaction, and found that N-myc downstream regulated gene 2 (NDRG2), a member of a new family of differentiation-related genes, was expressed in DCs. While DCs derived from CD34(+) progenitor cells also showed strong NDRG2 expression, the corresponding mRNA expression was absent in other cell lines including monocytes, B cells, and NK cells. The inhibition of DC differentiation by dexamethasone or vitamin D(3) treatment down-regulated the expression of the NDRG2 gene in DCs. In addition, gene expression was induced in a myelomonocytic leukemia cell line, which is capable of differentiating into DCs in cytokine-conditioned culture. The level of NDRG2 gene expression in DCs was significantly higher than that of other members of the NDRG gene family. Finally, in contrast to the stable NDRG2 expression in CD40-stimulated DCs, the induction of DC maturation by lipopolysaccharide (LPS) resulted in the down-regulation of NDRG2 gene expression. This down-regulation is likely to be due to a modification and subsequent destabilization of NDRG2 mRNA, because co-treating with actinomycin D and LPS significantly blocked this LPS effect. Taken together, our results indicate that NDRG2 is expressed during the differentiation of DCs, and that NDRG2 gene expression is differentially regulated by maturation-inducing stimuli.

Nuclear annexin II negatively regulates growth of LNCaP cells and substitution of ser 11 and 25 to glu prevents nucleo-cytoplasmic shuttling of annexin II

BACKGROUND

Annexin II heavy chain (also called p36, calpactin I) is lost in prostate cancers and in a majority of prostate intraepithelial neoplasia (PIN). Loss of annexin II heavy chain appears to be specific for prostate cancer since overexpression of annexin II is observed in a majority of human cancers, including pancreatic cancer, breast cancer and brain tumors. Annexin II exists as a heterotetramer in complex with a protein ligand p11 (S100A10), and as a monomer. Diverse cellular functions are proposed for the two forms of annexin II. The monomer is involved in DNA synthesis. A leucine-rich nuclear export signal (NES) in the N-terminus of annexin II regulates its nuclear export by the CRM1-mediated nuclear export pathway. Mutation of the NES sequence results in nuclear retention of annexin II.

RESULTS

Annexin II localized in the nucleus is phosphorylated, and the appearance of nuclear phosphorylated annexin II is cell cycle dependent, indicating that phosphorylation may play a role in nuclear entry, retention or export of annexin II. By exogenous expression of annexin II in the annexin II-null LNCaP cells, we show that wild-type annexin II is excluded from the nucleus, whereas the NES mutant annexin II localizes in both the nucleus and cytoplasm. Nuclear retention of annexin II results in reduced cell proliferation and increased doubling time of cells. Expression of annexin II, both wild type and NES mutant, causes morphological changes of the cells. By site-specific substitution of glutamic acid in the place of serines 11 and 25 in the N-terminus, we show that simultaneous phosphorylation of both serines 11 and 25, but not either one alone, prevents nuclear localization of annexin II.

CONCLUSION

Our data show that nuclear annexin II is phosphorylated in a cell cycle-dependent manner and that substitution of serines 11 and 25 inhibit nuclear entry of annexin II. Aberrant accumulation of nuclear annexin II retards proliferation of LNCaP cells.

Molecular differentiation of high- and moderate-grade human prostate cancer by cDNA microarray analysis

The prognosis of men with moderate-grade prostate cancer is uncertain. At present, there are few if any reliable molecular markers that can distinguish moderate-grade tumors from those that behave more aggressively. To better understand the molecular basis of human prostate cancer and potentially provide information toward more accurate prognosis, we measured and analyzed gene expression profiles of 13 high- and moderate-grade human prostate tumors using cDNA microarrays. The expression of 136 genes was observed to differ significantly (P < 0.001) between normal prostate and tumors using one-sample t testing and Wilcoxon ranking. Hierarchical clustering of genes demonstrated a relatively similar pattern of differential expression across the tumors. However, importantly, permutation t tests (two-tailed P < 0.001) revealed 21 genes whose expression profiles segregated moderate- and high-grade tumors from each other, which was significantly (P < 0.03) greater than what was expected by chance. These results were compared in silico with prostate cancer profiling efforts performed by other groups, including a meta-analysis of four data sets, which validated many of the dysregulated genes. We suggest that these data provide insight into the molecular nature of clinically aggressive prostate cancer.

Dominant-negative hypoxia-inducible factor-1 alpha reduces tumorigenicity of pancreatic cancer cells through the suppression of glucose metabolism

In the tumor cells exposed to hypoxia, hypoxia-inducible factor-1 (HIF-1)-mediated adaptation responses such as angiogenesis and anaerobic metabolism are induced for their survival. We have recently reported that the constitutive expression of HIF-1 alpha renders pancreatic cancer cells resistant to apoptosis induced by hypoxia and glucose deprivation. We then established dominant-negative HIF-1 alpha (dnHIF-1 alpha) transfectants and examined their susceptibility to apoptosis and growth inhibition induced by hypoxia and glucose deprivation in vitro and their tumorigenicity in SCID mice. We further examined the expressions of aldolase A and Glut-1 in vitro and Glut-1 expression and glucose uptake in the tumor tissues and microvessel counts in the tumor tissues. As a result, dnHIF-1 alpha rendered the pancreatic cancer cells sensitive to apoptosis and growth inhibition induced by hypoxia and glucose deprivation. Also it abrogated the enhanced expression of Glut-1 and aldolase A mRNAs under hypoxia and reduced the expression of Glut-1 and the glucose uptake in the tumor tissues and consequently in vivo tumorigenicity. We found no significant difference in the microvessel counts among the tumor tissues. From these results, we suggest that the disruption of the HIF-1 pathway might be effective in the treatment of pancreatic cancers.

Adrenomedullin antagonist suppresses in vivo growth of human pancreatic cancer cells in SCID mice by suppressing angiogenesis

Since it is reported that adrenomedullin (AM) upregulated by hypoxia inhibits hypoxic cell death, we examined the effects of AM antagonist (AM C-terminal fragment; AM(22-52)) on the growth of pancreatic cancer cells. We, for the first time, demonstrated that AM antagonist significantly reduced the in vivo growth of the pancreatic cancer cell line. Immunohistochemical analysis demonstrated that the mean diameter of blood vessels was significantly smaller in the tumor tissues treated with AM antagonist than in those treated with AM N-terminal fragment (AM(1-25)), and that the PCNA-labeling index was lower in the former than in the latter. Then we demonstrated that AM antagonist showed no effect on the in vitro growth of the pancreatic cancer cell line. These results showed that AM played an important role in the growth of pancreatic cancer cells in vivo, suggesting that AM antagonist might be a useful tool for treating pancreatic cancers.

ALCAM/CD166 is up-regulated in low-grade prostate cancer and progressively lost in high-grade lesions

BACKGROUND

Activated leukocyte cell adhesion molecule (ALCAM, CD166) is expressed in various tissues, including malignant melanoma, prostate cancer cell lines, and prostate cancer. We aimed to clarify the expression patterns of ALCAM in normal and malignant prostate tissue.

METHODS

RNA from 54 matched pairs of microdissected prostate tissue (tumor and normal) was hybridized to a custom built 4K GeneChip. Frozen section immunohistochemistry was used to confirm the ALCAM expression.

RESULTS

Chip-based transcript analysis revealed an up-regulation of ALCAM in prostate cancer in 22% of cases. Immunohistochemistry showed a focally raised ALCAM expression in 81% and a decreased expression in 19% of cases. These expression patterns correlated significantly with Gleason tumor grade: ALCAM up-regulation was found in most low-grade tumors (Gleason grade 1-3), whereas down-regulation occurred preferentially in high-grade tumors (Gleason grade 4 and 5), although up-regulation of ALCAM expression was preserved in two Gleason grade 5 tumors.

CONCLUSION

ALCAM expression is commonly disturbed in prostate cancer, which might indicate a role of ALCAM in the progression of this disease.

MyD88 is involved in the signalling pathway for Taxol-induced apoptosis and TNF-alpha expression in human myelomonocytic cells

Taxol is an effective anti-tumour drug against a variety of tumour cells. Taxol directly induces apoptosis in addition to a G2/M cell cycle arrest. However, it remains poorly understood how Taxol induces apoptosis in tumour cells. Taxol induces the secretion of inflammatory cytokines in murine macrophages in a toll-like receptor-4 (TLR-4)-dependent manner in addition to its anti-tumour effects, but the effect of Taxol on human macrophages is controversial. In this study, we demonstrated that low doses (less than 1000 nmol/l) of Taxol induced the expression of tumour necrosis factor (TNF)-alpha in human myelomonocytic cells and that the induction of TNF-alpha mRNA was inhibited by dominant-negative myeloid differentiation protein (dnMyD88). Furthermore, we demonstrated that the same doses of Taxol induced apoptosis of the same myelomonocytic cells and that the Taxol-induced apoptosis was also inhibited by dnMyD88. In accordance with the previous reports, Taxol induced the expression of TNF-alpha and apoptosis in a TLR4-independent manner. These results suggest that TNF-alpha expression and apoptosis, both induced by Taxol in human myelomonocytic cells, share the signal transduction molecule MyD88.

Hypoxia enhances the expression of autocrine motility factor and the motility of human pancreatic cancer cells

The incidence of distant metastases is higher in the tumours with low oxygen pressure than in those with high oxygen pressure. It is well known that hypoxia induces the transcription of various genes involved in angiogenesis and anaerobic metabolism necessary for the growth of tumour cells in vivo, suggesting that hypoxia may also induce the transcription of metastasis-associated genes. We sought to identify the metastasis-associated genes differentially expressed in tumour cells under hypoxic conditions with the use of a DNA microarray system. We found that hypoxia enhanced the expression of autocrine motility factor mRNA in various cancer cells and also enhanced the random motility of pancreatic cancer cells. Autocrine motility factor inhibitors abrogated the increase of motility under hypoxic conditions. In order to explore the roles of hypoxia-inducible factor-1alpha, we established hypoxia-inducible factor-1alpha-transfectants and dominant negative hypoxia-inducible factor-1alpha-transfectants. Transfection with hypoxia-inducible factor-1alpha and dominant-negative hypoxia-inducible factor-1alpha enhanced and suppressed the expression of autocrine motility factor/phosphohexase isomerase/neuroleukin mRNA and the random motility, respectively. These results suggest that hypoxia may promote the metastatic potential of cancer cells through the enhanced autocrine motility factor/phosphohexase isomerase/neuroleukin mRNA expression and that the disruption of the hypoxia-inducible factor-1 pathway may be an effective treatment for metastasis.

Thymosin-beta4 regulates motility and metastasis of malignant mouse fibrosarcoma cells

We identified a thymosin-beta4 gene overexpression in malignant mouse fibrosarcoma cells (QRsP-30) that were derived from clonal weakly tumorigenic and nonmetastatic QR-32 cells by using a differential display method. Thymosin-beta4 is known as a 4.9-kd polypeptide that interacts with G-actin and functions as a major actin-sequestering protein in cells. All of the six malignant fibrosarcoma cell lines that have been independently converted from QR-32 cells expressed high levels of thymosin-beta4 mRNA and its expression in tumor cells was correlated with tumorigenicity and metastatic potential. Up-regulation of thymosin-beta4 in QR-32 cells (32-S) transfected with sense thymosin-beta4 cDNA converted the cells to develop tumors and formed numerous lung metastases in syngeneic C57BL/6 mice. In contrast, antisense thymosin-beta4 cDNA-transfected QRsP-30 (30-AS) cells reduced thymosin-beta4 expression, and significantly lost tumor formation and metastases to distant organs. Vector-alone transfected cells (32-V or 30-V cells) behaved like their parental cells. We observed that tumor cell motility, cell shape, and F-actin organization is regulated in proportion to the level of thymosin-beta4 expression. These findings indicate that thymosin-beta4 molecule regulates fibrosarcoma cell tumorigenicity and metastasis through actin-based cytoskeletal organization.

Autocrine production of epithelial cell–derived neutrophil attractant-78 induced by granulocyte colony-stimulating factor in neutrophils

Whereas mobilization to inflammatory sites is an important function of neutrophils, it remains to be determined whether granulocyte colony-stimulating factor (G-CSF) stimulates the mobilization of neutrophils to the inflammatory sites. This study compared the expression of more than 9000 genes in neutrophils treated with and without G-CSF with the use of a DNA microarray system to determine the effects of G-CSF on the function of neutrophils. It was found that messenger RNA expression of epithelial cell–derived neutrophil attractant-78 (ENA-78), which has been reported to be a chemotactic factor for neutrophils, was induced by G-CSF in neutrophils. The study demonstrated that the supernatant of G-CSF–treated neutrophils induced the chemotaxis of neutrophils and that anti–ENA-78 antibody and anti–CXCR-2 antibody inhibited the chemotaxis. These data suggest that G-CSF may enhance the mobilization of neutrophils and consequently augment the accumulation of neutrophils in the inflammatory sites through the secretion of ENA-78.