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

Galectin-8 inhibition and functions in immune response and tumor biology

Galectins are among organisms' most abundantly expressed lectins (carbohydrate-binding proteins) that specifically bind β-galactosides. They act not only outside the cell, where they bind to extracellular matrix glycans, but also inside the cell, where they have a significant impact on signaling pathways. Galectin-8 is a galectin family protein encoded by the LGALS8 gene. Its role is evident in both T- and B-cell immunity and in the innate immune response, where it acts directly on dendritic cells and induces some pro-inflammatory cytokines. Galectin-8 also plays an important role in the defense against bacterial and viral infections. It is known to promote antibacterial autophagy by recognizing and binding glycans present on the vacuolar membrane, thus acting as a danger receptor. The most important role of galectin-8 is the regulation of cancer growth, metastasis, tumor progression, and tumor cell survival. Importantly, the expression of galectins is typically higher in tumor tissues than in noncancerous tissues. In this review article, we focus on galectin-8 and its function in immune response, microbial infections, and cancer. Given all of these functions of galectin-8, we emphasize the importance of developing new and selective galectin-8 inhibitors and report the current status of their development.

ALCAM is a biomarker of tumor aggressiveness and worse prognosis in glottic laryngeal squamous cell carcinoma

BACKGROUND

Laryngeal squamous cell carcinoma (LSCC) is the second most frequent head and neck tumor. Prognosis of patients with LSCC has not improved in recent decades, showing a need for the identification of prognostic biomarkers and new therapeutic targets. Recently, we showed that ALCAM overexpression was associated with glottic LSCC prognosis.

OBJECTIVES AND METHODS

Aiming to validate the prognostic value of ALCAM, we evaluate the ALCAM protein levels by immunohistochemistry in 263 glottic LSCC surgically treated with neck dissection.

RESULTS

ALCAM was expressed in 48.7% and overexpressed in 36.5% of glottic LSCC samples. ALCAM overexpression was associated with lymph node metastasis (p = 0.030), lymphovascular involvement (p = 0.0002), high-grade tumors (p = 0.025), and tumor relapse (p = 0.043). Multivariate survival analyses showed an overfitting between ALCAM overexpression and lymph node metastasis as a prognostic variable.

CONCLUSIONS

High ALCAM expression was associated with an aggressive glottic LSCC profile.

Inhibition of miR-214 expression by small molecules alleviates head and neck cancer metastasis by targeting ALCAM/TFAP2 signaling

Predominantly, head and neck cancer (HNC) is considered a regional disease and develops in the nasal cavity, oral cavity, tongue, pharynx, and larynx. In the advanced stage, the HNC spread into distant organs. By the time head and neck cancer diagnosed, the estimated metastasis is occurred in 10-40% cases. The most important vital organs affected by distant metastasis are the lungs, bones, and liver. Despite several advancements in chemotherapies, no significant changes are observed as 5-year survival rate remains the same. Therefore, it is crucial to decipher molecular mechanisms contributing to the metastatic dissemination of head and neck cancer. Here, we tested a novel ALCAM/TFAP2 signaling by targeting multidisciplinary miR-214 expression in head and cancer cells. Our results revealed that HNC cell lines (CAL27, SCC-9, SCC-4, and SCC-25) exhibit higher expression of miR-214 compared with normal human bronchial epithelial (NHBE) cells. Higher expression of miR-214 drives the invasive potential of these cell lines. Down-regulation of miR-214 in CAL27 and SCC-9 cells either using an anti-miR-214 inhibitor (50nM) or a small molecule of green tea (EGCG) inhibited cell invasion. Treating CAL27 and SCC-9 cells with EGCG also reduces ALCAM expression, a key activated leukocyte cell adhesion molecule, potentially blocking mesenchymal phenotype. Dietary administration of EGCG significantly inhibits distant metastasis of SCC-9 cells into the lungs, liver, and kidneys. Our results also demonstrate that the reduction of miR-214 expression influences in vitro cell movement and extravasation, as evident by reduced CD31 expression, a neovascularization marker. Together, these studies suggest that identifying bioactive molecules that can inhibit distant metastasis regulated by the miRNAs may provide potent interventional approaches and a better understanding of the complex functions of miRNAs and their therapeutic targets for clinical application.

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.

ALCAM/CD166: A pleiotropic mediator of cell adhesion, stemness and cancer progression

Activated Leukocyte Cell Adhesion Molecule (ALCAM/CD166) is a glycoprotein involved in homotypic and heterotypic cell adhesion. ALCAM can be proteolytically cleaved at the cell surface by metalloproteases, which generate shedding of its ectodomain. In various tumors, ALCAM is overexpressed and serves as a valuable prognostic marker of disease progression. Moreover, CD166 has been identified as a putative cancer stem cell marker in particular cancers. Herein, we summarize biochemical aspects of ALCAM, including structure, proteolytic shedding, alternative splicing, and specific ligands, and integrate this information with biological functions of this glycoprotein including cell adhesion, migration and invasion. In addition, we discuss different patterns of ALCAM expression in distinct tumor types and its contribution to tumor progression. Finally, we highlight the role of ALCAM as a cancer stem cell marker and introduce current clinical trials associated with this molecule. Future studies are needed to define the value of shed ALCAM in biofluids or ALCAM isoform expression as prognostic biomarkers in tumor progression.

The role of activated leukocyte cell adhesion molecule (ALCAM) in cancer progression, invasion, metastasis and recurrence: A novel cancer stem cell marker and tumor-specific prognostic marker

Activated leukocyte cell adhesion molecule (ALCAM) or CD166 is a 100 to 105 KDa transmembrane immunoglobulin which is involved in activation of T-cells, hematopoiesis, neutrophils trans-endothelial migration, angiogenesis, inflammation and tumor propagation and invasiveness through formation of homophilic and heterophilic interactions. Recently, many studies have proposed that the expression pattern of ALCAM is highly associated with the grade, stage and invasiveness of tumors. Although ALCAM is a valuable prognostic marker in different carcinomas, similar expression patterns in different tumor types may be associated with completely different prognostic states, making it to be a tumor-type-dependent prognostic marker. In addition, ALCAM isoforms provide ways for primary detection of tumor cells with metastatic potential. More importantly, this prognostic marker has shown to be considerably dependent on the cytoplasmic and membranous expression, indirect and direct regulation of post-transcriptional molecules, pro-apoptotic proteins functionalities and several other oncogenic proteins or signalling pathways. This review mainly focuses on the pathways involved in expression of ALCAM and its prognostic value of in different types of cancers and the way in which it is regulated.

Tumoral Expression of CD166 in Human Esophageal Squamous Cell Carcinoma: Implications for Cancer Progression and Prognosis

Accumulating data showed that cancer stem cells (CSCs) identified by cell surface markers contribute to the initiation, progression, and prognosis of human cancers. In this study, the expression of CSC candidates CD166, CD44, and Lgr5 in 65 cases of esophageal squamous cell carcinoma (ESCC) and 16 cases of control esophageal tissues were examined with immunohistochemistry (IHC). The correlation between tumoral expression levels of these CSC candidates and clinicopathological variables was analyzed. IHC results showed that the expression of CD166 in esophageal control tissues was completely negative, but it was in 87.69% (57/65) ESCC tissues. The expression of CD44 and Lgr5 did not differ between esophageal control tissues and ESCC tissues (p > 0.05). In addition, there were not correlations found among the expression levels of CD166, CD44, and Lgr5 in ESCC tissues. Clinicopathological analysis revealed that the tumoral expression level of CD166 correlated with lymph node involvement and TNM staging in patients with ESCC, and lower tumoral expression of CD44 was found in patients with advanced TNM staging. Kaplan-Meier survival curves suggested that expression level of CD166 appeared to have a negative impact on overall survival rate after surgery in patients with ESCC. Such impact was not found in other two CSC candidates. The authors therefore conclude that CD166 is a potential prognostic biomarker and correlates with advanced progression features in patients with ESCC.

Indium-111-labeled CD166-targeted peptide as a potential nuclear imaging agent for detecting colorectal cancer stem-like cells in a xenograft mouse model

BACKGROUND

Cancer stem cells (CSCs) are involved in drug resistance, metastasis, and relapse of cancers, which can significantly affect tumor therapy. Hence, to develop specifically therapeutic target probe at CSCs for improvement of survival and quality of life of cancer patients is urgently needed. The CD166 protein has been suggested to be involved in colorectal cancer (CRC) tumorigenesis and to be considered a marker for colorectal CSCs (CRCSCs) detection. In this study, therefore, we attend to apply a nuclear imaging agent probe, Glycine₁₈-Cystine-linked CD166-targeted peptides (CD166tp-G₁₈C), to detect the changes of CD166 level in a CRC xenograft mouse model.

RESULTS

We isolated the CD166-positive cells from the HCT15 CRC cell line (CD166⁺HCT15) and evaluated their morphology and ability of clone formation, migration, protein expression, and drug resistance. The CD166-positive HCT15 cells display the CSCs characteristics. We discovered and designed a CD166-targeted peptide (CD166tp-G₁₈C) as a targeted probe of CRC stem-like cell for cell binding assay. The CD166tp-G₁₈C confirmed the CD166 protein targeting ability in CD166⁺HCT15 cells. The diethylenetriaminopentaacetic acid (DTPA)-conjugated CD166tp-G₁₈C further was labeled with indium-111 (¹¹¹In-DTPA-CD166tp-G₁₈C) as nuclear imaging agent for imaging and bio-distribution analysis in vivo. Finally, we observed that the ¹¹¹In-DTPA-CD166tp-G₁₈C was significantly enhanced in tumor tissues of CD166⁺HCT15 xenograft mice as compared to the non-CD166tp-G₁₈C control.

CONCLUSIONS

Our results indicated that the indium-111-labeled CD166tp-G₁₈C may be served as a powerful tool for colorectal CSCs nuclear imaging in the CRC patients.

Downregulation of CD166 inhibits invasion, migration, and EMT in the radio-resistant human nasopharyngeal carcinoma cell line CNE-2R

Objective: CD166 is known as a tumor stem cell specific marker, associating with tumor metastasis. The purpose of this study was to further discuss CD166 gene on cell proliferation, invasion, metastasis, and the epithelial-mesenchymal transition (EMT) in CNE-2R cell line of nasopharyngeal carcinoma (NPC). Materials and methods: CNE-2R cells were transfected with lentivirus CD166-shRNA, and quantitative reverse transcription polymerase chain reaction (RT-qPCR), and Western blotting were used to confirm the silencing effects. The wound healing test and transwell test were carried out to assess cell invasive and migratory abilities in vitro. With the establishment of xenograft nude mouse model, Western blotting and immunohistochemistry were undertaken to detect the expression level of E-cadherin, N-cadherin, and vimentin. In vivo metastasis detection was carried out by injecting tumor cells into nude mice via the tail vein. Results: The invasive and migratory abilities of CNE-2R cells were significantly reduced after CD166 was downregulated. In addition, silencing of CD166 of CNE-2R cells increased the expression of E-cadherin, while down-regulated the expression of N-cadherin and vimentin. Immunohistochemistry of tumors showed consistent results with in-situ tumor formation experiment. Additionally, the growth of transplanted tumor was inhibited. In addition, in vivo metastasis test proved that knockdown of CD166 suppressed pulmonary metastasis and liver metastasis according to hematoxylin and eosin (H&E) staining. Expression of E-cadherin increased, while expression of N-cadherin and vimentin decreased, as revealed by Western blotting of metastatic lung tumors. Conclusion: Silencing of CD166 in CNE-2R cells evidently inhibited proliferation, invasion, metastasis, and EMT process in vivo and in vitro.

Antibody drug conjugates under investigation in phase I and phase II clinical trials for gastrointestinal cancer

INTRODUCTION

Antibody drug conjugates (ADCs) represent a developing class of anticancer therapeutics which are designed to selectively deliver a cytotoxic payload to tumors, while limiting systemic toxicity to healthy tissues. There are several ADCs which are currently in various stages of clinical development for the treatment of gastrointestinal malignancies.

AREAS COVERED

We discuss the biologic rationale and review the clinical experience with ADCs in the treatment of gastrointestinal malignancies, summarizing the pre-clinical and phase I/II clinical trial data that have been completed or are ongoing.

EXPERT OPINION

While there have been significant advances in the development of ADCs since they were first introduced, several challenges remain. These challenges include (i) the selection of an ideal antigen target which is tumor specific and internalized upon binding, (ii) selection of an antibody which has high affinity for its antigen target and low immunogenicity, (iii) selection of a potent payload which is cytotoxic at sub-nanomolar concentrations, and (iv) optimal design of a linker to confer ADC stability with limited off-site toxicity. Efforts are ongoing to address these issues and innovate the ADC technology to improve the safety and efficacy of these agents.

Activated leucocyte cell adhesion molecule (ALCAM/CD166) regulates T cell responses in a murine model of food allergy

Food allergy is a major public health problem. Studies have shown that long-term interactions between activated leucocyte cell adhesion molecule (ALCAM/CD166) on the surface of antigen-presenting cells, and CD6, a co-stimulatory molecule, influence immune responses. However, there are currently no studies on the functions of ALCAM in food allergy. Therefore, we aimed to identify the functions of ALCAM in ovalbumin (OVA)-induced food allergy using ALCAM-deficient mice. Wild-type (WT) and ALCAM-deficient (ALCAM^-/- ) mice were sensitized intraperitoneally and with orally fed OVA. The mice were killed, and parameters related to food allergy and T helper type 2 (Th2) immune responses were analysed. ALCAM serum levels increased and mRNA expression decreased in OVA-challenged WT mice. Serum immunoglobulin (Ig)E levels, Th2 cytokine mRNA and histological injuries were higher in OVA-challenged WT mice than in control mice, and these were attenuated in ALCAM^-/- mice. T cell proliferation of total cells, CD3⁺ CD4⁺ T cells and activated T cells in immune tissues were diminished in OVA-challenged ALCAM^-/- mice. Proliferation of co-cultured T cells and dendritic cells (DCs) was decreased by the anti-CD6 antibody. In addition, WT mice sensitized by adoptive transfer of OVA-pulsed ALCAM^-/- BM-derived DCs showed reduced immune responses. Lastly, serum ALCAM levels were higher in children with food allergy than in control subjects. In this study, serum levels of ALCAM were elevated in food allergy-induced WT mice and children with food allergy. Moreover, immune responses and T cell activation were attenuated in OVA-challenged ALCAM^-/- mice. These results indicate that ALCAM regulates food allergy by affecting T cell activation.

Prognostic Significance of Activated Leukocyte Cell Adhesion Molecule (ALCAM) in Association with Promoter Methylation of the ALCAM Gene in Breast Cancer

Activated leukocyte cell adhesion molecule (ALCAM) has been implicated in tumorigenesis. In this study, we studied DNA methylation status of the ALCAM gene using pyrosequencing in breast cancer tissues. We analyzed the association between the methylation status of the ALCAM gene and its expression. Also, the effects of inflammation on the ALCAM gene methylation and its expression were investigated. The ALCAM gene methylation was associated with the ALCAM transcripts in tumor tissues. The methylation status of the ALCAM gene was not significantly different between tumor and normal tissues. The level of ALCAM transcripts was associated with the expression of TNFα, NF-κB p50, IL-4, and intratumoral inflammation. The IHC expression of ALCAM was associated with histologic grade, HER2 overexpression and molecular subtype. The expression of TNFα, NF-κB p50, and IL-4 showed significant association with the clinicopathologic characteristics. In conclusion, the ALCAM gene methylation was related to the level of ALCAM transcripts. Also, the level of ALCAM transcripts was associated with the inflammatory markers in breast cancer. Our results suggest that the methylation of the ALCAM gene contributes to the decreased expression of ALCAM. Also, ALCAM is linked to the inflammatory response in breast cancer.

Epigenetic alterations of the Igf2 promoter and the effect of miR‑483‑5p on its target gene expression in esophageal squamous cell carcinoma

Esophageal squamous cell carcinoma (ESCC) is one of the most widespread malignancies in China. MicroRNAs (miRNAs/miRs) are endogenous evolutionarily-conserved small non-coding RNAs that are able to regulate ESCC formation and deterioration by negatively regulating specific target genes. In the present study, the expression levels of miR-483-5p and its associated mRNAs were measured by quantitative polymerase chain reaction (PCR) analysis, and the methylation levels of the insulin-like growth factor 2 (Igf2) promoter were detected via the methylation-specific PCR method in serum and tissues from patients with ESCC. The results demonstrated that the expression level of miR-483-5p was significantly upregulated in preoperative serum and cancer tissues from patients with ESCC (P<0.01), and the miR-483-5p expression levels were correlated with the tumor, node, metastasis stage (P<0.05) and lymph node metastasis (P<0.05). In addition, the mRNA levels of miR-483-5p target genes (Rho GDP dissociation inhibitor α, activated leukocyte cell adhesion molecule, and suppressor of cytokine signaling 3) in cancer tissues were significantly decreased compared with adjacent non-cancerous tissues. These results indicated that miR-483-5p and its target genes may be involved in the developmental process of ESCC. The Igf2 levels in cancer tissues were significantly increased compared with adjacent non-cancerous tissues (P<0.01). Additionally, the methylation levels of the Igf2 promoter region were 31.82 and 54.55% in cancer tissues and adjacent non-cancerous tissues, respectively, suggesting that low methylation of the Igf2 gene promoter region may promote the expression of Igf2 and miR-483-5p; this, in turn, induces the degradation of miR-483-5p target genes, and leads to the upregulation of oncogenes and the downregulation of tumor suppressors, which promotes the development of ESCC.

Roles of microRNAs and RNA-Binding Proteins in the Regulation of Colorectal Cancer Stem Cells

Colorectal cancer stem cells (CSCs) are responsible for the initiation, progression and metastasis of human colorectal cancers, and have been characterized by the expression of cell surface markers, such as CD44, CD133, CD166 and LGR5. MicroRNAs (miRNAs) are differentially expressed between CSCs and non-tumorigenic cancer cells, and play important roles in the maintenance and regulation of stem cell properties of CSCs. RNA binding proteins (RBPs) are emerging epigenetic regulators of various RNA processing events, such as splicing, localization, stabilization and translation, and can regulate various types of stem cells. In this review, we summarize current evidences on the roles of miRNA and RBPs in the regulation of colorectal CSCs. Understanding the epigenetic regulation of human colorectal CSCs will help to develop biomarkers for colorectal cancers and to identify targets for CSC-targeting therapies.

Can recurrences be predicted in craniopharyngiomas? β-catenin coexisting with stem cells markers and p-ATM in a clinicopathologic study of 45cases

Background

Recurrence is a common feature of craniopharyngiomas, benign tumors that origin from squamous epithelial remnants of Rathke’s pouch- arising at any segment of its whole course. There are two histotypes, showing different morphology and clinical behavior: adamantinomatous(adaCP) and papillary (papCP). An univocal strategy of management has not yet been defined, being considered the combination of surgery and radiotherapy the most effective, especially in case of incomplete resection. Therefore, the identification of factors influencing the biological and clinical behaviour is of paramount importance.

β-catenin is a cell-cell adhesion protein, whose nuclear localization has been linked to the pathogenesis of adaCP: its nuclear accumulation is associated to the presence of a tumor stem cell subpopulation. The latter is made of cells capable of self-renewal, hence believed to be responsible of recurrence, metastases and resistance to therapy in all tumors.

ATM is a kinase activated by autophosphorylation (p-ATM) upon DNA double-strand breaks. It is involved not only in DNA repair, but also in tumor migration and invasiveness. Its expression may have prognostic implications in many neoplastic diseases.

Methods

In this study, we measured the immunohistochemical expression of β-catenin, stem cell markers (CD133, CD166), Ki67 and pATMin 45 craniopharyngiomas and correlated it with clinicopathologic features.

Results

Statistical analysis revealed strong correlation of β-catenin with recurrence (p = 0.0039), Ki67 (p = 0.0011, r = 0.4903) and CD166 (p = 0.0002, r = 0.6218). A slight tendency to a higher expression of β-catenin was recorded for adaCP rather than papCP (p = 0.0895).Fisher’s exact test showed that CD166 was significantlyrelated with recurrence (p = 0.0040). Furthermore, cytoplasmic pATM was more expressed in adaCPs (p = 0.0470), compared to papCPs that displayed a more evident nuclear signal (p = 0.0313) instead.

Conclusions

Backing upon these data, we could weigh in on the need of identifying β-catenin and CD166 as prognostic markersthat could be useful in predicting thebiologicalbehavior, as recurrence risk incraniopharyngiomas. The final goal is to drew up a prognostic algorithm to be of aid in the planning of an appropriate treatment strategy. Furthermore, our findings demonstrate that pATM could be used as additional distinction-marker between the two histotypes.

Evaluation of ALCAM, PECAM-1 and selectin levels in intracranial meningiomas

OBJECTIVES

Cell adhesion molecules play a major role in various pathological states. The aim of this study was to evaluate the tissue levels of selectins (E-, L-, and P-Selectins), activated leukocyte cell adhesion molecule (ALCAM) and platelet endothelial cell adhesion molecule-1 (PECAM-1) in intracranial meningiomas and compare with the levels in control tissues.

PATIENTS AND METHODS

20 consecutive patients who were operated on meningiomas (grade-I: 17 and grade-II: 3) and 15 cerebral tissues obtained during the autopsy procedures as a resource for the healthy controls were included in this study.

RESULTS

All three selectins', ALCAM and PECAM-1 levels were found to be significantly higher in meningiomas when compared with the control tissues (p<0.001, p<0.001, p<0.001, p<0.05, p<0.001), respectively.

CONCLUSIONS

According to our results, the adhesion molecules were found to be higher in meningiomas suggesting that they may be involved in the pathological process of this type of brain tumors. We conceive that developing alternate therapies such as immunotherapeutic approaches against brain tumors might be amendatory in the treatment. Since this is the first study performed in meningioma type brain tumors demonstrating and comparing the levels of various adhesion molecules with control tissues, further clinical and experimental studies are needed to support our current findings with higher number of patients.

Genetic Variation in CD166 Gene and Its Association with Bladder Cancer Risk in North Indian Population

Adhesion molecules play a key role in cancer progression and tumorigenesis. Genetic polymorphism of adhesion molecules may alter the normal functioning thereby leading to bladder cancer susceptibility. Hence we aimed to evaluate three SNPs of CD166 gene (CD166rs6437585 C/T, CD166rs10511244 C/T, and CD166rs1157 A/G) in bladder cancer patients and normal controls of North Indian population. A total of 270 healthy controls and 240 confirmed bladder cancer patients were recruited for this study. Three SNPs of CD166 gene viz. CD166rs6437585 C/T, CD166rs10511244 C/T, and CD166rs1157 A/G were selected for this study. CD166rs6437585 C/T and CD166rs10511244 C/T were genotyped by Taqman allelic discrimination assay and CD166rs1157 A/G was genotyped by PCR-RFLP. The statistical analysis was done using the SPSS software, version 16.0 (SPSS, Chicago, IL), and p < 0.05 was considered statistically significant. Haplotypic analysis was done by using SNP analyzer version 1.2A. CD166rs6437585 C/T and CD166rs10511244 C/T showed significant association with reduced risk in bladder cancer while CD166rs1157 A/G showed significant high risk along with association at genotypic and allelic levels. Haplotypic analysis showed 1.8-folds risk in CCG combination, whereas CTA and TCG showed significant association with reduced risk. Further stratification on the basis of smoking, tumor grade/stage and BGC therapy revealed no association of these three polymorphic sites of CD166. Our study suggests that CD166rs6437585 C/T and CD166rs10511244 C/T are predictive for the reduced risk of bladder cancer, whereas CD166rs1157 A/G had shown significant association with high risk of bladder cancer in North Indians. This somehow suggests that CD166rs1157 A/G can be used as a marker for risk prediction of bladder cancer.

Characterization of cancer stem cells from different grades of human colorectal cancer

Colorectal cancer (CRC) is one of the most common solid tumors worldwide. Recent evidence suggests that a population of cancer cells, called cancer stem cells (CSCs), is responsible for tumor heterogeneity, invasion, metastasis, therapeutic resistance, and recurrence of CRC. The isolation and characterization of CSCs using cell surface markers have been reported previously with varying results. In this study, we investigated a panel of four putative CSC markers, CD44, CD24, CD166, and EpCAM, to define CRC-CSC. Paraffin embedded tissue samples from different grades of primary, untreated CRC were analyzed for the expression of four CSC markers CD44, CD326, CD24, and CD166, using immunohistochemistry. Flow cytometric analysis of CRC-CSC from HT29 (low grade) and HCT116 (high grade) human colorectal cancer cell lines was done. Marker-based isolation of CSC and non-CSC-bulk-tumor cells from HT29 was done using FACS, and tumor sphere assay was performed. There was a statistically significant difference (p < 0.05) in the expression of CD44, CD326, and CD166 between cases and controls. A novel cutoff distribution of CD44 and CD166 was suggested to help for better immunohistochemical analysis of CRC. Higher prevalence of CSC was seen in high-grade CRC as compared to low-grade CRC. Sorted and cultured CD44 + CD166+ cells formed tumor spheres, suggesting that these cells, having properties of self renewal and anchorage independent proliferation, were in fact CSC. Hence, CD44 and CD166 may serve as good CRC-CSC markers when used together with novel cutoff immunohistochemistry (IHC) expression levels.

Targeting ALCAM in the cryo-treated tumour microenvironment successfully induces systemic anti-tumour immunity

Cryoablative treatment has been widely used for treating cancer. However, the therapeutic efficacies are still controversial. The molecular mechanisms of the cryo-induced immune responses, particularly underlying the ineffectiveness, remain to be fully elucidated. In this study, we identified a new molecular mechanism involved in the cryo failure. We used cryo-ineffective metastatic tumour models that murine melanoma B16-F10 cells were subcutaneously and intravenously implanted into C57BL/6 mice. When the subcutaneous tumours were treated cryoablation on day 7 after tumour implantation, cells expressing activated leucocyte cell adhesion molecule (ALCAM/CD166) were significantly expanded not only locally in the treated tumours but also systemically in spleen and bone marrow of the mice. The cryo-induced ALCAM(+) cells including CD45(-) mesenchymal stem/stromal cells, CD11b(+)Gr1(+) myeloid-derived suppressor cells, and CD4(+)Foxp3(+) regulatory T cells significantly suppressed interferon γ production and cytotoxicity of tumour-specific CD8(+) T cells via ALCAM expressed in these cells. This suggests that systemic expansion of the ALCAM(+) cells negatively switches host-immune directivity to the tumour-supportive mode. Intratumoural injection with anti-ALCAM blocking monoclonal antibody (mAb) following the cryo treatment systemically induced tumour-specific CD8(+) T cells with higher cytotoxic activities, resulting in suppression of tumour growth and metastasis in the cryo-resistant tumour models. These suggest that expansion of ALCAM(+) cells is a determinant of limiting the cryo efficacy. Further combination with an immune checkpoint inhibitor anti-CTLA4 mAb optimized the anti-tumour efficacy of the dual-combination therapy. Targeting ALCAM may be a promising strategy for overcoming the cryo ineffectiveness leading to the better practical use of cryoablation in clinical treatment of cancer.

PRMT1 regulates tumor growth and metastasis of human melanoma via targeting ALCAM

Overexpression of protein arginine methyltransferases (PRMTs) is associated with various types of cancer. The present study aimed to determine the expression level of PRMT1 in human melanoma and investigate its biological function. The clinical significance of PRMT1 was determined by screening the Oncomine database, and the increased expression of PRMT in melanoma was confirmed by western blot analysis. Furthermore, the current study demonstrated that PRMT1 was overexpressed in melanoma cell lines compared with human immortalized keratinocytes and PIG1 immortalized human melanocytes. Silencing PRMT1 in A375 and Hs294T cells significantly suppressed tumor growth and metastatic ability of the melanoma cell line compared with the negative control. These changes were in accordance with the upregulation of the cadherin 1 level and downregulation of several metastatic‑associated genes determined by a quantitative polymerase chain reaction array. Liquid chromatography‑mass spectrometry demonstrated that activated leukocyte cell adhesion molecule (ALCAM) may be a direct target of PRMT1, and the interaction was confirmed by co‑immunoprecipitation. Compared with negative controls, the protein level of ALCAM was decreased following the silencing of PRMT1, and re‑expression of ALCAM in A375/shPRMT1 or Hs294T/shPRMT1 cells using an expression vector restored the colony formation and metastatic ability of the cells. In conclusion, the current results indicated that PRMT1 is overexpressed in human melanoma, and may regulate tumor growth and metastasis via targeting ALCAM.

MCAM, as a novel receptor for S100A8/A9, mediates progression of malignant melanoma through prominent activation of NF-κB and ROS formation upon ligand binding

The dynamic interaction between tumor cells and their microenvironment induces a proinflammatory milieu that drives cancer development and progression. The S100A8/A9 complex has been implicated in chronic inflammation, tumor development, and progression. The cancer microenvironment contributes to the up-regulation of this protein complex in many invasive tumors, which is associated with the formation of pre-metastatic niches and poor prognosis. Changing adhesive preference of cancer cells is at the core of the metastatic process that governs the reciprocal interactions of cancer cells with the extracellular matrices and neighboring stromal cells. Cell adhesion molecules (CAMs) have been confirmed to have high-level expression in various highly invasive tumors. The expression and function of CAMs are profoundly influenced by the extracellular milieu. S100A8/A9 mediates its effects by binding to cell surface receptors, such as heparan sulfate, TLR4 and RAGE on immune and tumor cells. RAGE has recently been identified as an adhesion molecule and has considerably high identity and similarity to ALCAM and MCAM, which are frequently over-expressed on metastatic malignant melanoma cells. In this study, we demonstrated that ALCAM and MCAM also function as S100A8/A9 receptors as does RAGE and induce malignant melanoma progression by NF-κB activation and ROS formation. Notably, MCAM not only activated NF-κB more prominently than ALCAM and RAGE did but also mediated intracellular signaling for the formation of lung metastasis. MCAM is known to be involved in malignant melanoma development and progression through several mechanisms. Therefore, MCAM is a potential effective target in malignant melanoma treatment.

Squamous Cell Carcinoma - Similarities and Differences among Anatomical Sites

Squamous cell carcinoma (SCC) is an epithelial malignancy involving many anatomical sites and is the most common cancer capable of metastatic spread. Development of early diagnosis methods and novel therapeutics are important for prevention and mortality reduction. In this effort, numerous molecular alterations have been described in SCCs. SCCs share many phenotypic and molecular characteristics, but they have not been extensively compared. This article reviews SCC as a disease, including: epidemiology, pathology, risk factors, molecular characteristics, prognostic markers, targeted therapy, and a new approach to studying SCCs. Through this comparison, several themes are apparent. For example, HPV infection is a common risk factor among the four major SCCs (NMSC, HNSC, ESCC, and NSCLC) and molecular abnormalities in cell-cycle regulation and signal transduction predominate. These data reveal that the molecular insights, new markers, and drug targets discovered in individual SCCs may shed light on this type of cancer as a whole.

miR-483-5p promotes invasion and metastasis of lung adenocarcinoma by targeting RhoGDI1 and ALCAM

The nodal regulatory properties of microRNAs (miRNA) in metastatic cancer may offer new targets for therapeutic control. Here, we report that upregulation of miR-483-5p is correlated with the progression of human lung adenocarcinoma. miR-483-5p promotes the epithelial-mesenchymal transition (EMT) accompanied by invasive and metastatic properties of lung adenocarcinoma. Mechanistically, miR-483-5p is activated by the WNT/β-catenin signaling pathway and exerts its prometastatic function by directly targeting the Rho GDP dissociation inhibitor alpha (RhoGDI1) and activated leukocyte cell adhesion molecule (ALCAM), two putative metastasis suppressors. Furthermore, we found that downregulation of RhoGDI1 enhances expression of Snail, thereby promoting EMT. Importantly, miR-483-5p levels are positively correlated with β-catenin expression, but are negatively correlated with the levels of RhoGDI1 and ALCAM in human lung adenocarcinoma. Our findings reveal that miR-483-5p is a critical β-catenin-activated prometastatic miRNA and a negative regulator of the metastasis suppressors RhoGDI1 and ALCAM.

P21 and CD166 as predictive markers of poor response and outcome after fluorouracil-based chemoradiotherapy for the patients with rectal cancer

Background

Pre-operative chemoradiotherapy (CRT) is the standard treatment in clinical stage T3/4 or node positive rectal cancer. However, there are no established biomarkers that can predict the pathological response and clinical outcome to CRT.

Methods

Immunohistochemical staining was performed in tissue arrays constructed from core tissue specimens taken before treatment and from operative specimens from 112 patients who received 5-FU based pre-operative CRT and surgery. Expression of Ki67, TS, BAX, EpCAM, p53, p21, EGFR, CD44, CD133, CD166, HIF1α and ALDH1 were assessed and correlated with tumor regression grades and disease free survival.

Results

Of the 112 patients (M/F 74/38, median age: 62), 20 (17.9%) patients achieved pathologic complete remission (pCR). In analyzing the associations between marker expressions and tumor regression grades, high p21 expression at the pretreatment biopsy was significantly associated with non-pCR (p = 0.022) and poor disease free survival (median DFS - low vs high p21: 75.8 vs 58.1 months, p = 0.002). In the multivariate analysis, high p21 expression level at the pre-treatment biopsy was significantly associated with poor DFS (p = 0.001, HR 6.14; 95% CI 2.03, 18.55). High CD166 expression level at the pretreatment biopsy was also associated with poor DFS (p = 0.003; HR 5.61; 95% CI 1.81, 17.35).

Conclusion

These show high p21 and CD166 expression at the pretreatment biopsy were associated with tumor regression and poor prognosis in patients treated with 5-FU based CRT. Larger, prospective and functional studies are warranted to determine the role of p21 and CD166 as predictive biomarker of response to CRT.

Prognostic value of CD166 expression in cancers of the digestive system: a systematic review and meta-analysis

Objective

Many studies have reported the prognostic predictive value of CD166 as a cancer stem cell marker in cancers of the digestive system; however, its predictive value remains controversial. Here, we investigate the correlation between CD166 positivity in digestive system cancers and clinicopathological features using meta-analysis.

Methods

A comprehensive search in PubMed and ISI Web of Science through March of 2013 was performed. Only articles containing CD166 antigen immunohistochemical staining in cancers of the digestive system were included,including pancreatic cancer, esophageal cancer, gastric cancer and colorectal cancer. Data comparing 3- and 5-year overall survival along with other clinicopathological features were collected.

Results

Nine studies with 2553 patients who met the inclusion criteria were included for the analysis. The median rate of CD166 immunohistochemical staining expression was 56% (25.4%–76.3%). In colorectal cancer specifically, the results of a fixed-effects model indicated that CD166-positive expression was an independent marker associated with a smaller tumor burden (T category; RR = 0.93, 95%, CI: 0.88–0.98) but worse spread to nearby lymph nodes (N category; RR = 1.17, 95% CI: 1.05–1.30). The 5-year overall survival rate was showed relationship with cytoplasmic positive staining of CD166 (RR = 1.47 95% 1.21–1.79), but no significant association was found in the pool or any other stratified analysis with 3- or 5- year overall survival rate.

Conclusion

Based on the published studies, different cellular location of CD166 has distinct prognostic value and cytoplasmic positive expression is associated with worse prognosis outcome. Besides, our results also find CD166 expression indicate advanced T category and N-positive status in colorectal cancer specifically.

Plasma membrane proteomics of tumor spheres identify CD166 as a novel marker for cancer stem-like cells in head and neck squamous cell carcinoma

Patients with advanced head and neck squamous cell carcinoma (HNSCC) have a poor prognosis with the currently available therapy, and tumor recurrence is frequently observed. The discovery of specific membrane-associated cancer stem cell (CSC) markers is crucial for the development of novel therapeutic strategies to target these CSCs. To address this issue, we established sphere cultures to enrich CSCs and used them for plasma membrane proteomics to identify specific membrane signatures of the HNSCC spheres. Of a dataset that included a total of 376 identified proteins, 200 were bona fide membrane proteins. Among them, 123 proteins were at least 1.5-fold up- or down-regulated in the spheres relative to the adherent cultures. These proteins included cell adhesion molecules, receptors, and transporter proteins. Some of them play key roles in wnt, integrin, and TGFβ signaling pathways. When we compared our dataset with two published hESC membrane protein signatures, we found 18 proteins common to all three of the databases. CD166 and CD44 were two such proteins. Interestingly, the expression of CD166, rather than that of the well-established HNSCC CSC marker CD44, was significantly related to the malignant behavior of HNSCC. Relative to CD166(low) HNSCC cells, CD166(high) HNSCC cells had a greater sphere-formation ability in vitro and tumor formation ability in vivo. Patients whose tumors expressed high levels of CD166 had a significantly poorer clinical outcome than those whose tumors expressed low levels of CD166 (cohort 1: 96 cases, p = 0.040), whereas the level of CD44 expression had only a marginal influence on the clinical outcome of patients with HNSCC (p = 0.078). The level of CD166 expression in HNSCC tumors was also associated with the tumor recurrence rate (cohort 2: 104 cases, p = 0.016). This study demonstrates that CD166 is a valuable cell surface marker for the enrichment of HNSCC stem cells and that plasma membrane proteomics is a promising biological tool for investigating the membrane proteins of CSCs.

Activated leukocyte cell adhesion molecule is a marker for thyroid carcinoma aggressiveness and disease-free survival

BACKGROUND

Currently, there are no protein biomarkers for aggressive subtypes of thyroid carcinomas (TC) in clinical use that would allow for early detection and patient management. We hypothesized that activated leukocyte cell adhesion molecule (ALCAM or CD166) expression in thyroid tissues will reveal ALCAM to be a potential diagnostic and/or prognostic marker for TC aggressiveness.

METHODS

Forty-five benign and 158 malignant thyroid tissues were analyzed for ALCAM expression using immunohistochemistry. ALCAM expression was correlated with different subtypes and clinicopathological features of TC, as well as patient disease-free survival.

RESULTS

Combined membranous and cytoplasmic (total) expression of ALCAM was significantly reduced in patients with poorly/undifferentiated (aggressive) TC as compared to well-differentiated (nonaggressive) tumors (p<0.001; area-under-curve=0.865, sensitivity=82%, specificity=74%). The decreased ALCAM expression in TC correlated significantly with extrathyroidal extension, distant metastasis, and TC histotype. Notably, Kaplan-Meier survival analysis for follow-up data of 134 patients revealed significantly reduced disease-free survival for patients with TC with decreased ALCAM membranous, cytoplasmic, and total expression. Median survival of patients with decreased cytoplasmic ALCAM expression was 6 years, as compared to 13.7 years for patients with higher ALCAM expression (p<0.001).

CONCLUSION

ALCAM has the potential to serve as a diagnostic and prognostic biomarker for aggressive TC. This protein can be taken forward for analysis in sera of patients with TC to determine its applicability as a minimally invasive serum biomarker for TC aggressiveness and patient disease-free survival.

HMMC-1, a human monoclonal antibody to fucosylated core 1 O-glycan, suppresses growth of uterine endometrial cancer cells

HMMC-1 is a human monoclonal antibody that reacts with a fucosylated and extended core 1 O-glycan, Fucα1-2Galβ1-4GlcNAcβ1-3Galβ1-3GalNAc-Ser/Thr, as an epitope. In the present study, we examined the effects of HMMC-1 on cell proliferation of two human uterine endometrial cancer cell lines, HEC8 and HEC9, to investigate the role of glycoproteins bearing the HMMC-1 epitope in cancer progression. HEC9 cells expressed high levels of the HMMC-1 epitope, but HMMC-1 reactivity was hardly detected in HEC8 cells. In a mouse model of lymph node metastasis using orthotopic implantation, HEC8 and HEC9 showed low (10%) and high (80%) metastatic potency, respectively. Growth of HEC9, but not HEC8, was remarkably inhibited by addition of HMMC-1 to the culture medium. Cell cycle analysis and expression analysis showed that HMMC-1 treatment increased the G(1) phase population of HEC9 cells and induced cyclin-dependent kinase inhibitors p16 and p21. Two glycoproteins, 97 and 137 kDa, with a strong reactivity to HMMC-1 were purified, and the 97-kDa glycoprotein was identified as CD166, an immunoglobulin superfamily cell adhesion molecule assumed to be involved in cancer metastasis. CD166 gene-silencing dramatically reduced HMMC-1 epitope expression and growth in HEC9 cells, indicating that CD166 is the primary glycoprotein presenting the HMMC-1 epitope in HEC9 cells. Collectively, HMMC-1 might arrest the cell cycle in the G(1) phase by binding to O-glycans on the CD166 expressed in HEC9 cells, raising the possibility that HMMC-1 extensively inhibits invasive growth of HMMC-1 epitope-positive uterine endometrial cancer cells by targeting the cancer-associated form of CD166.

Activated leukocyte cell-adhesion molecule (ALCAM) promotes malignant phenotypes of malignant mesothelioma

INTRODUCTION

Cell-adhesion molecules play important roles involving the malignant phenotypes of human cancer cells. However, detailed characteristics of aberrant expression status of cell-adhesion molecules in malignant mesothelioma (MM) cells and their possible biological roles for MM malignancy remain poorly understood.

METHODS

DNA microarray analysis was employed to identify aberrantly expressing genes using 20 MM cell lines. Activated leukocyte cell-adhesion molecule (ALCAM) expression in MM cell lines was analyzed with quantitative reverse transcription-polymerase chain reaction and Western blot analyses in 47 primary MM specimens with immunohistochemistry. ALCAM knockdown in MM cell lines was performed with lentivirus-mediated short hairpin RNA (shRNA) transduction. Purified soluble ALCAM (sALCAM) protein was used for in vitro experiments, whereas MM cell lines infected with the sALCAM-expressing lentivirus were tested for tumorigenicity in vivo.

RESULTS

ALCAM, a member of the immunoglobulin superfamily, was detected as one of the most highly upregulated genes among 103 cell-adhesion molecules with microarray analysis. Elevated expression levels of ALCAM messenger RNA and protein were detected in all 20 cell lines. Positive staining of ALCAM was detected in 26 of 47 MM specimens (55%) with immunohistochemistry. ALCAM knockdown with shRNA suppressed cell migration and invasion of MM cell lines. Purified sALCAM protein impaired the migration and invasion of MM cells in vitro, and the infection of sALCAM-expressing virus into MM cells significantly prolonged survival periods of MM-transplanted nude mice in vivo.

CONCLUSION

Our study suggests that overexpression of ALCAM contributes to tumor progression in MM and that ALCAM might be a potential therapeutic target of MM.

Cloning of the human activated leukocyte cell adhesion molecule promoter and identification of its tissue-independent transcriptional activation by Sp1

Activated leukocyte cell adhesion molecule (ALCAM) belongs to the immunoglobulin cell adhesion molecule super family. ALCAM is implicated in tumor progression, inflammation, and the differentiation of hematopoietic stem cells. Hitherto, the identity of regulatory DNA elements and cognate transcription factors responsible for ALCAM gene expression remained unknown. In this report, the human ALCAM promoter was cloned and its transcriptional mechanisms elucidated. The promoter is TATA-less and contains multiple GC-boxes. A proximal 650-bp promoter fragment conferred tissue-independent activation, whereas two contiguous regions upstream of this region negatively influenced promoter activity in a tissue-specific manner. The positive regulatory promoter region was mapped to a core 50 base pair sequence containing a conical Sp1 element. Mutation analysis revealed that this element alone or in tandem with elements immediately upstream was required for maximal promoter activity. Chromatin analysis revealed that Sp1 binds exclusively to the canonical binding sequence in vivo, but not to DNA sequence immediately upstream. Finally, we showed that over-expression of Sp1 significantly increased the basal promoter activity. Thus, Sp1 activated the ALCAM promoter in most cells. These findings have important ramifications for unraveling the roles of ALCAM in inflammation and tumorigenesis.

ALCAM regulates motility, invasiveness, and adherens junction formation in uveal melanoma cells

ALCAM, a member of the immunoglobulin superfamily, has been implicated in numerous developmental events and has been repeatedly identified as a marker for cancer metastasis. Previous studies addressing ALCAM's role in cancer have, however, yielded conflicting results. Depending on the tumor cell type, ALCAM expression has been reported to be both positively and negatively correlated with cancer progression and metastasis in the literature. To better understand how ALCAM might regulate cancer cell behavior, we utilized a panel of defined uveal melanoma cell lines with high or low ALCAM levels, and directly tested the effects of manipulating these levels on cell motility, invasiveness, and adhesion using multiple assays. ALCAM expression was stably silenced by shRNA knockdown in a high-ALCAM cell line (MUM-2B); the resulting cells displayed reduced motility in gap-closure assays and a reduction in invasiveness as measured by a transwell migration assay. Immunostaining revealed that the silenced cells were defective in the formation of adherens junctions, at which ALCAM colocalizes with N-cadherin and ß-catenin in native cells. Additionally, we stably overexpressed ALCAM in a low-ALCAM cell line (MUM-2C); intriguingly, these cells did not exhibit any increase in motility or invasiveness, indicating that ALCAM is necessary but not sufficient to promote metastasis-associated cell behaviors. In these ALCAM-overexpressing cells, however, recruitment of ß-catenin and N-cadherin to adherens junctions was enhanced. These data confirm a previously suggested role for ALCAM in the regulation of adherens junctions, and also suggest a mechanism by which ALCAM might differentially enhance or decrease invasiveness, depending on the type of cadherin adhesion complexes present in tissues surrounding the primary tumor, and on the cadherin status of the tumor cells themselves.

Cancer-initiating enriched cell lines from human glioblastoma: preparing for drug discovery assays

Glioblastoma multiforme (GBM) is the most lethal type of brain tumour in the adult humans. The cancer-initiating cell (CIC) hypothesis supports the notion that failures in current approaches to GBM treatment might be attributed to the survival of the CIC subpopulation. Recent evidence shows the idea that using CIC-enriched cell lines derived from human GBM as new targets for drug discovery programs, may improve the chance of successfully translating the basic research findings into clinical trials. Although this approach appears promising, many important biological and technical issues (characterization of functional CIC markers, inter- and intra-tumoral CIC heterogeneity, and isolation and maintenance inconsistency) need to be resolved.

Relevance of activated leukocyte cell adhesion molecule (ALCAM) in tumor tissue and sera of cervical cancer patients

Background

An altered expression of the activated leukocyte cell adhesion molecule (ALCAM) is associated with cancer progression in various cancer types. In some cancers ALCAM has a prognostic value or is predictive for the benefit of therapeutic interventions. To date there are no data on the role of ALCAM in cervical cancer available.

Methods

In this study, ALCAM expression was analysed by immunohistochemistry (IHC) in tissue samples of 233 patients with cervical cancer, among them 178 with complete follow-up information. In addition, soluble (s-)ALCAM was measured in sera of a subset of the included patients (n = 55) by enzyme-linked immunosorbent assay (ELISA).

Results

ALCAM overexpression was detected (immunoreactive score (IRS) 2-12) in 58.4% of the cervical cancer samples. The normal ectocervical or endocervical epithelium showed no ALCAM reactivity. In untreated patients, ALCAM overexpression in tumor tissue tended to be associated with shorter cancer-specific survival (CSS) and disease-free survival (DFS). Patients, whose tumor samples showed ALCAM overexpression receiving a cytotoxic therapy like radiotherapy or chemoradiation, however, had a favourable prognosis compared to those patients, whose cancers showed no or minimal ALCAM staining. This effect was particularly apparent in patients receiving chemoradiation where the CSS was significantly longer in patients with ALCAM-positive tumors (p = 0.038; cumulative incidence rates at 96 months 8%, 95% CI 0%-23%, and 26%, CI 3%-43% in ALCAM-positive and ALCAM-negative cases, respectively).

Median preoperative s-ALCAM concentration in sera from tumor patients was 27.6 ng/ml (range 17.5-55.1 ng/ml, mean 28.9 ng/ml), serum levels did not correlate with intratumoral ALCAM expression.

Conclusions

The data of our retrospective study suggest that the prognostic value of ALCAM expression in cervical carcinoma might be therapy-dependent, and that ALCAM might function as a predictive marker for the response to chemoradiation. This should be confirmed in further, prospective studies.

ALCAM (CD166) expression and serum levels are markers for poor survival of esophageal cancer patients

The expression of the activated leukocyte cell adhesion molecule (ALCAM and CD166) is increased in various types of cancer. We aimed to evaluate its role as a prognostic marker for esophageal cancer (EC). We retrospectively analyzed ALCAM expression in 299 primary lesions, 147 lymph node and 46 distant metastases from EC patients, on a tissue microarray using immunohistochemistry. Bone marrow samples from representative cancer patients (n = 16), taken before primary surgery, were stained by double-immunofluorescence for ALCAM and cytokeratins (CK). Blood serum samples from 236 cancer patients and 127 controls were analyzed for serum ALCAM (s-ALCAM) by ELISA. The immunohistochemical analysis showed increased ALCAM expression in the majority of lesions (primary tumor 71%, lymph node 76% and distant metastases 80%). ALCAM expression was not associated with histopathological parameters except for tumor grading (p = 0.015). ALCAM-positive patients had significantly worse recurrence-free and overall survival (OS; p = 0.002). Disseminated tumor cells (DTC) in bone marrow showed two phenotypes, ALCAM+/CK+ (36%) and ALCAM-/CK+ (64%). Multivariate analysis revealed that ALCAM expression and elevated s-ALCAM serum values are powerful prognostic variables for OS in patients with EC (hazard ratio [HR] 3.987, 95% confidence interval [95%CI] 1.906-8.340, p < 0.001 and HR 1.915, 95%CI 1.021-3.592, p = 0.043). The results of our study provide preliminary evidence for the potential clinical utility of ALCAM as a prognostic biomarker for EC, which might be a basis for future clinical application. In addition, ALCAM expression in a subset of DTC of the bone marrow indicates a potential function in the metastatic cascade of EC.

Activated leukocyte cell adhesion molecule expression and shedding in thyroid tumors

Activated leukocyte cell adhesion molecule (ALCAM, CD166) is expressed in various tissues, cancers, and cancer-initiating cells. Alterations in expression of ALCAM have been reported in several human tumors, and cell adhesion functions have been proposed to explain its association with cancer. Here we documented high levels of ALCAM expression in human thyroid tumors and cell lines. Through proteomic characterization of ALCAM expression in the human papillary thyroid carcinoma cell line TPC-1, we identified the presence of a full-length membrane-associated isoform in cell lysate and of soluble ALCAM isoforms in conditioned medium. This finding is consistent with proteolytically shed ALCAM ectodomains. Nonspecific agents, such as phorbol myristate acetate (PMA) or ionomycin, provoked increased ectodomain shedding. Epidermal growth factor receptor stimulation also enhanced ALCAM secretion through an ADAM17/TACE-dependent pathway. ADAM17/TACE was expressed in the TPC-1 cell line, and ADAM17/TACE silencing by specific small interfering RNAs reduced ALCAM shedding. In addition, the CGS27023A inhibitor of ADAM17/TACE function reduced ALCAM release in a dose-dependent manner and inhibited cell migration in a wound-healing assay. We also provide evidence for the existence of novel O-glycosylated forms and of a novel 60-kDa soluble form of ALCAM, which is particularly abundant following cell stimulation by PMA. ALCAM expression in papillary and medullary thyroid cancer specimens and in the surrounding non-tumoral component was studied by western blot and immunohistochemistry, with results demonstrating that tumor cells overexpress ALCAM. These findings strongly suggest the possibility that ALCAM may have an important role in thyroid tumor biology.

Functional polymorphisms in CD166/ALCAM gene associated with increased risk for breast cancer in a Chinese population

Activated Leukocyte Cell Adhesion Molecules (ALCAM, also called CD166, MEMD) are cell surface immunoglobulins that are considered to be prognostic markers for breast cancer. CD166/ALCAM has gained increasing attention because of its significant association with tumor progression and the metastatic spread of breast cancer. Two polymorphisms have been identified in the CD166/ALCAM gene: 5'UTR C/T (rs6437585) and 3'UTR A/G (rs11559013). We analyzed the genotypes of 1033 individuals with breast cancer, and 1116 controls; odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using logistic regression. The effects and functions of polymorphisms were examined using luciferase gene expression assays and real-time PCR analyses. Our data demonstrated that individuals with the rs6437585 CT + TT genotype had an OR of 1.38 (95% CI, 1.11-1.72) for developing breast cancer, compared to those with the CC genotype. The T allele increased the risk of breast cancer in a dose-dependent manner (P (trend) < 0.001). However, there were no significant differences found between cases and controls at the rs11559013 A/G site. Additional experiments that we performed, which focused on reporter gene expression driven by CD166/ALCAM promoters, demonstrated that the presence of an rs6437585 T allele led to greater transcriptional activity than the rs6437585 C allele. This was consistent with the increased cancer risk that we observed in our case-control analysis.

Characterization of the intestinal cancer stem cell marker CD166 in the human and mouse gastrointestinal tract

BACKGROUND & AIMS

CD166 (also called activated leukocyte cell adhesion molecule [ALCAM]) is a marker of colorectal cancer (CRC) stem cells; it is expressed by aggressive tumors. Although the presence of CD166 at the tumor cell surface has been correlated with shortened survival, little is known about its function and expression in normal intestinal epithelia.

METHODS

We characterized the expression pattern of CD166 in normal intestinal tissue samples from humans and mice using immunohistochemisty, flow cytometry, and quantitative reverse-transcriptase polymerase chain reaction. Human and mouse intestinal tumors were also analyzed.

RESULTS

CD166 was expressed on the surface of epithelial cells within the stem cell niche and along the length of the intestine; expression was conserved across species. In the small intestine, CD166 was observed on crypt-based Paneth cells and intervening crypt-based columnar cells (putative stem cells). A subset of CD166-positive, crypt-based columnar cells coexpressed the stem cell markers Lgr5, Musashi-1, or Dcamkl-1. CD166 was located in the cytoplasm and at the surface of cells within human CRC tumors. CD166-positive cells were also detected in benign adenomas in mice; rare cells coexpressed CD166 and CD44 or epithelial-specific antigen.

CONCLUSIONS

CD166 is highly expressed within the endogenous intestinal stem cell niche. CD166-positive cells appear at multiple stages of intestinal carcinoma progression, including benign and metastatic tumors. Further studies should investigate the function of CD166 in stem cells and the stem cell niche, which might have implications for normal intestinal homeostasis. CD166 has potential as a therapeutic target for CRC.

Mechanisms of transcriptional regulation and prognostic significance of activated leukocyte cell adhesion molecule in cancer

Background

Activated leukocyte cell adhesion molecule (ALCAM) is implicated in the prognosis of multiple cancers with low level expression associated with metastasis and early death in breast cancer. Despite this significance, mechanisms that regulate ALCAM gene expression and ALCAM's role in adhesion of pre-metastatic circulating tumor cells have not been defined. We studied ALCAM expression in 20 tumor cell lines by real-time PCR, western blot and immunochemistry. Epigenetic alterations of the ALCAM promoter were assessed using methylation-specific PCR and bisulfite sequencing. ALCAM's role in adhesion of tumor cells to the vascular wall was studied in isolated perfused lungs.

Results

A common site for transcription initiation of the ALCAM gene was identified and the ALCAM promoter sequenced. The promoter contains multiple cis-active elements including a functional p65 NF-κB motif, and it harbors an extensive array of CpG residues highly methylated exclusively in ALCAM-negative tumor cells. These CpG residues were modestly demethylated after 5-aza-2-deoxycytidine treatment. Restoration of high-level ALCAM expression using an ALCAM cDNA increased clustering of MDA-MB-435 tumor cells perfused through the pulmonary vasculature of ventilated rat lungs. Anti-ALCAM antibodies reduced the number of intravascular tumor cell clusters.

Conclusion

Our data suggests that loss of ALCAM expression, due in part to DNA methylation of extensive segments of the promoter, significantly impairs the ability of circulating tumor cells to adhere to each other, and may therefore promote metastasis. These findings offer insight into the mechanisms for down-regulation of ALCAM gene expression in tumor cells, and for the positive prognostic value of high-level ALCAM in breast cancer.

Combination of osteopontin and activated leukocyte cell adhesion molecule as potent prognostic discriminators in HER2- and ER-negative breast cancer

BACKGROUND

To analyse the discriminative impact of osteopontin (OPN) and activated leukocyte cell adhesion molecule (ALCAM), combined with human epidermal growth factor 2 (HER2) and oestrogen receptor (ER) in breast cancer.

METHODS

Osteopontin, ALCAM, HER2 and ER mRNA expression in breast cancer tissues of 481 patients were analysed (mRNA microarray analysis, kinetic RT-PCR). Hierarchical clustering was performed in training cohort A (N=100, adjuvant treatment) and validation cohorts B (N=200, no adjuvant treatment, low-risk) and C (N=181, adjuvant treatment, high-risk).

RESULTS

Negative/low ER and HER2, high OPN and low ALCAM mRNA expression helped to identify patients at particularly high risk, showing shorter DFS, P<0.001, and OAS, P=0.001. Although both validation cohorts showed diverse risk and treatment profiles, this marker constellation was concordantly associated with shorter DFS and OAS (P<0.001 and P=0.075 for cohort B and P=0.043 and P<0.001 for cohort C, respectively). In multivariate analysis, this algorithm was the main independent prognostic factor. Cohort B: DFS, P=0.0065, OAS, not significant; cohort C: DFS, P=0.026, OAS, P<0.001.

CONCLUSION

Activated leukocyte cell adhesion molecule and OPN mRNA expression has a strong discriminative impact on survival within cancer patients with low or negative expression of ER and HER2, so called 'high-risk' breast cancers, and might help in identifying patients who could benefit from new treatment approaches like targeted therapies in the adjuvant setting.