Biologic role of activated leukocyte cell adhesion molecule overexpression in breast cancer cell lines and clinical tumor tissue

Annexin A1 Is Involved in the Antitumor Effects of 5-Azacytidine in Human Oral Squamous Carcinoma Cells

Background: the treatment of squamous cell carcinomas of the oral cavity (OSCCs) is limited by the lack of reliable diagnostic/prognostic, and predictive markers, as well as by intrinsic tumor cell heterogeneity. 5-azacytidine (5-AZA) offers opportunities for cancer cell reprogramming to develop new target-specific treatments. The protein annexin A1 (ANXA1) is downregulated in head and neck squamous cell carcinoma (HNSCC), correlated with pathological differentiation grade. Objectives: this work aimed to further investigate the role of ANXA1 in OSCC progression based on 5-AZA activity. Methods: we used CAL27 and CAL33 cell lines, which differ in drug sensitivity and differentiation status. Results: CAL27 showed a higher expression of the stemness markers compared to CAL33 cells, but this positivity was lost after treatment with 5-AZA. This drug also decreased CAL27 cell motility, promoting a less aggressive phenotype. Moreover, 5-AZA increased ANXA1 expression only in CAL27. After siRNA-mediated downmodulation, we witnessed a significant rise in cell motility and the inversion of E-/N-cadherin expression, which was reverted again by 5-AZA. To investigate the role of exogenous ANXA1 derived from the tumor microenvironment, we treated CAL27 with Ac2-26, an ANXA1 mimetic peptide. Interestingly, we found that this peptide alone showed impacts similar to 5-AZA in reversing the aggressive phenotype. All these effects were not evidenced in CAL33 cells. Finally, to prove the loop of the exogenous protein, we detected increased expression of its receptors, formyl peptide receptors (FPRs), and their activation, leading to oncosuppressor effects. Conclusions: we propose that ANXA1 mediates the effects of 5-AZA only in poorly differentiated stemlike CAL27 cell lines. This suggests the relevance of ANXA1 as a diagnostic/prognostic biomarker in OSCCs, paving the way for personalized therapies to overcome treatment difficulties.

CD6 in Human Disease

CD6 is a cell surface protein expressed by T cells, a subset of NK cells, a small population of B cells, and thymocytes. CD6 has multiple and complex functions due to its distinct functional epitopes that mediate interactions with several ligands including CD166 (ALCAM) and CD318 (CDCP1). An additional molecule, CD44, is being investigated as a potential new ligand of CD6. CD6 plays critical roles in lymphocyte activation, proliferation, and adhesion to antigen-presenting, epithelial, and cancer cells. CD6 is a risk gene for multiple autoimmune diseases, possibly related to its numerous roles in regulating CD4+T-cell responses. Additionally, CD6 is a potential target for cancer immunotherapy. Here, we dissect the role of CD6 in the pathogenesis of more than 15 diseases and discuss recent data supporting the use of CD6-targeted therapy in humans.

Ligands of CD6: roles in the pathogenesis and treatment of cancer

Cluster of Differentiation 6 (CD6), an established marker of T cells, has multiple and complex functions in regulation of T cell activation and proliferation, and in adhesion of T cells to antigen-presenting cells and epithelial cells in various organs and tissues. Early studies on CD6 demonstrated its role in mediating cell-cell interactions through its first ligand to be identified, CD166/ALCAM. The observation of CD6-dependent functions of T cells that could not be explained by interactions with CD166/ALCAM led to discovery of a second ligand, CD318/CDCP1. An additional cell surface molecule (CD44) is being studied as a potential third ligand of CD6. CD166, CD318, and CD44 are widely expressed by both differentiated cancer cells and cancer stem-like cells, and the level of their expression generally correlates with poor prognosis and increased metastatic potential. Therefore, there has been an increased focus on understanding how CD6 interacts with its ligands in the context of cancer biology and cancer immunotherapy. In this review, we assess the roles of these CD6 ligands in both the pathogenesis and treatment of cancer.

The prognostic value of stem cell markers in triple-negative breast cancer

Among the many consecutive theories of cancer, the stem cell theory is currently the most accepted one. Cancer stem cells are located in small niches with specific environment, renew themselves and are believed to be responsible for many recurrences. They can be highlighted with stem cell markers, but often these markers also label tumor cells, and this may represent a phenotypical change associated with prognosis. In this study, we attempted to match tumor outcomes with the expression of the following stem cell markers: ALDH1, AnnexinA1, CD44, CD117, CD166, Nanog and oct-4. Tissue microarray blocks from triple-negative breast cancers were immunostained for the listed markers, and their expression by the majority of tumor cells (diffuse positivity) was correlated with prognosis. Of the 106 tumors investigated, diffuse positivity was seen in 7 (ALDH1), 33 (AnnexinA1), 53 (CD44), 44 (CD117 membranous only), 49 (CD117), 72 (CD166), 19 (Nanog), and 11 (oct-4) cases. With a median follow-up of 83 months, ALDH1 and CD117 expression was associated with DFS, whereas CD44, CD117 and CD166 were associated with OS estimates, based on Kaplan-Meier analyses. In the multivariate Cox proportional hazard models (including the examined markers and clinicopathological data which had a statistical impact in the univariate analysis), the pN category and the lack of ALDH1 expression were independent prognosticators for DFS, and the pN category and diffuse CD44 staining were independent prognosticators for OS. In the multivariate analysis including all of the examined clinicopathological data and markers, only CD117 showed a statistical impact on OS. We failed to demonstrate a prognostic impact for most stem cell markers tested in triple-negative breast cancer, but lack of ALDH1 staining and CD44 expression appears as of prognostic value, requiring further examination in independent studies.

TMT-Based Multiplexed Quantitation of N-Glycopeptides Reveals Glycoproteome Remodeling Induced by Oncogenic Mutations

Glycoproteomics, or the simultaneous characterization of glycans and their attached peptides, is increasingly being employed to generate catalogs of glycopeptides on a large scale. Nevertheless, quantitative glycoproteomics remains challenging even though isobaric tagging reagents such as tandem mass tags (TMT) are routinely used for quantitative proteomics. Here, we present a workflow that combines the enrichment or fractionation of TMT-labeled glycopeptides with size-exclusion chromatography (SEC) for an in-depth and quantitative analysis of the glycoproteome. We applied this workflow to study the cellular glycoproteome of an isogenic mammary epithelial cell system that recapitulated oncogenic mutations in the PIK3CA gene, which codes for the phosphatidylinositol-3-kinase catalytic subunit. As compared to the parental cells, cells with mutations in exon 9 (E545K) or exon 20 (H1047R) of the PIK3CA gene exhibited site-specific glycosylation alterations in 464 of the 1999 glycopeptides quantified. Our strategy led to the discovery of site-specific glycosylation changes in PIK3CA mutant cells in several important receptors, including cell adhesion proteins such as integrin β-6 and CD166. This study demonstrates that the SEC-based enrichment of glycopeptides is a simple and robust method with minimal sample processing that can easily be coupled with TMT-labeling for the global quantitation of glycopeptides.

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.

Trailblazing perspectives on targeting breast cancer stem cells

Breast cancer (BCa) is one of the most prevalent malignant tumors affecting women's health worldwide. The recurrence and metastasis of BCa have made it a long-standing challenge to achieve remission-persistent or disease-undetectable clinical outcomes. Cancer stem cells (CSCs) possess the ability to self-renew and generate heterogeneous tumor bulk. The existence of CSCs has been found to be vital in the initiation, metastasis, therapy resistance, and recurrence of tumors across cancer types. Because CSCs grow slowly in their dormant state, they are insensitive to conventional chemotherapies; however, when CSCs emerge from their dormant state and become clinically evident, they usually acquire genetic traits that make them resistant to existing therapies. Moreover, CSCs also show evidence of acquired drug resistance in synchrony with tumor relapses. The concept of CSCs provides a new treatment strategy for BCa. In this review, we highlight the recent advances in research on breast CSCs and their association with epithelial-mesenchymal transition (EMT), circulating tumor cells (CTCs), plasticity of tumor cells, tumor microenvironment (TME), T-cell modulatory protein PD-L1, and non-coding RNAs. On the basis that CSCs are associated with multiple dysregulated biological processes, we envisage that increased understanding of disease sub-classification, selected combination of conventional treatment, molecular aberration directed therapy, immunotherapy, and CSC targeting/sensitizing strategy might improve the treatment outcome of patients with advanced BCa. We also discuss novel perspectives on new drugs and therapeutics purposing the potent and selective expunging of CSCs.

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.

Dual in vitro invasion/migration suppressing and tamoxifen response modulating effects of a recombinant anti-ALCAM scFv on breast cancer cells

It has been shown that overexpression of activated leukocyte cell adhesion molecule (ALCAM) is involved in development of resistance to tamoxifen therapy and promotion of cell invasion, migration and metastasis in ER+ breast cancer cells. Thus, we hypothesized that blockade of ALCAM interconnections with antibodies could be an effective approach for reversing mentioned negative events associated with ALCAM overexpression in breast cancer cells. Here, an anti-ALCAM scFv was recombinantly expressed and used throughout study for examination of the putative anticancer effects of ALCAM blockade. The anti-ALCAM scFv coding sequence was obtained from GenBank database and after addition of a 6× His-tag moiety, signal peptide and flanking sequences, the whole construct was expressed in Escherichia coli. Tamoxifen resistant MCF7 cells were then pretreat for 24 hours with purified recombinant anti-ALCAM scFv prior to administration of tamoxifen. In parallel, the cytotoxicity profile of anti-ALCAM scFv and tamoxifen co-treatments against tamoxifen resistant and sensitive MCF7 cell lines was also evaluated using CompuSyn software. The invasion/migration inhibitory effects of anti-ALCAM scFv on MDA-MB-231 cells were also evaluated. Pretreatment with anti-ALCAM scFv could successfully enhance anti-proliferative effects of tamoxifen against resistant MCF-7 cell lines. Furthermore, the combination of 19.2:1 of tamoxifen to anti-ALCAM scFv demonstrated synergistic cell inhibitory effect against tamoxifen resistant MCF7 cell lines. Also, incubating MDA-MB-231 cell lines with anti-ALCAM scFv resulted in a 30% and 25% reduction in number of invaded and migrated cells respectively. Overall, application of anti-ALCAM scFv could significantly suppress cancer cells metastasis in vitro and modulate tamoxifen resistant ER+ MCF7 cell line's sensitivity to tamoxifen. SIGNIFICANCE OF THE STUDY: Acquisition of resistance to tamoxifen therapy is one of the major challenges associated with cancer chemotherapy, gradually turning a responsive tumour into a refractory more invasive one which ultimately ends in disease progression and relapse. Here, we reported expression of an anti-ALCAM scFv, capable of increasing the sensitivity of tamoxifen resistant ER+ MCF-7 cells to tamoxifen therapy following a 24-hour pretreatment period. In addition, we demonstrated that the anti-ALCAM scFv monotherapy was also capable of suppressing invasion and migration of MDA-MB-231 cells in Boyden chamber assays.

Importance of activated leukocyte cell adhesion molecule (ALCAM) in prostate cancer progression and metastatic dissemination

Activated Leukocyte Cell Adhesion Molecule (ALCAM) has been linked to the progression of numerous human cancers, where it appears to play a complex role. The current study aims to further assess the importance of ALCAM in prostate cancer and the prognostic potential of serum ALCAM as a biomarker for prostate cancer progression. Here we demonstrate enhanced levels of tissue ALCAM are associated with metastasis. Additionally, elevated serum ALCAM is indicative of progression and poorer patient outlook, and demonstrates comparable prognostic ability to PSA in terms of metastasis and prostate cancer survival. ALCAM suppression enhanced proliferation and invasiveness in PC-3 cells and motility/migration in PC-3 and LNCaP cells. ALCAM suppressed PC-3 cells were generally less responsive to HGF and displayed reduced MET transcript expression. Furthermore a recombinant human ALCAM-Fc chimera was able to inhibit LNCaP cell attachment to HECV and hFOB1.19 cells. Taken together, ALCAM appears to be a promising biomarker for prostate cancer progression, with enhanced serum expression associated with poorer prognosis. Suppression of ALCAM appears to impact cell function and cellular responsiveness to certain micro environmental factors.

Dual knockdown of Galectin-8 and its glycosylated ligand, the activated leukocyte cell adhesion molecule (ALCAM/CD166), synergistically delays in vivo breast cancer growth

Galectin-8 (Gal-8), a 'tandem-repeat'-type galectin, has been described as a modulator of cellular functions including adhesion, spreading, growth arrest, apoptosis, pathogen recognition, autophagy, and immunomodulation. We have previously shown that activated leukocyte cell adhesion molecule (ALCAM), also known as CD166, serves as a receptor for endogenous Gal-8. ALCAM is a member of the immunoglobulin superfamily involved in cell-cell adhesion through homophilic (ALCAM-ALCAM) and heterophilic (i.e. ALCAM-CD6) interactions in different tissues. Here we investigated the physiologic relevance of ALCAM-Gal-8 association and glycosylation-dependent mechanisms governing these interactions. We found that silencing of ALCAM in MDA-MB-231 triple negative breast cancer cells decreases cell adhesion and migration onto Gal-8-coated surfaces in a glycan-dependent fashion. Remarkably, either Gal-8 or ALCAM silencing also disrupted cell-cell adhesion, and led to reduced tumor growth in a murine model of triple negative breast cancer. Moreover, structural characterization of endogenous ALCAM N-glycosylation showed abundant permissive structures for Gal-8 binding. Importantly, we also found that cell sialylation controls Gal-8-mediated cell adhesion. Altogether, these findings demonstrate a central role of either ALCAM or Gal-8 (or both) in controlling triple negative breast cancer.

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.

Wnt5a-induced cell migration is associated with the aggressiveness of estrogen receptor-positive breast cancer

Elevated expression of Wnt5a is associated with malignancy, cell invasion, and metastasis. The role of Wnt5a expression in breast cancer remains elusive. We investigated the significance of Wnt5a expression in breast cancer. The relationship between Wnt5a expression and clinicopathologic factors was assessed in invasive breast cancer (n = 178) resected at Hiroshima University Hospital between January 2011 and February 2014. Wnt5a was expressed in 69 of 178 cases (39%) of invasive breast cancer and correlated strongly with estrogen receptor (ER) expression (P < 0.001). Wnt5a expression in ER-positive breast cancer correlated significantly with lymph node metastasis, nuclear grade, and lymphatic invasion. The recurrence-free survival was shorter in breast cancer patients with Wnt5a expression than in those without (P = 0.024). The migratory capacity of ER-positive breast cancer cells increased with constitutive expression of Wnt5a and decreased with Wnt5a knockdown. DNA microarray analysis identified activated leukocyte cell adhesion molecule (ALCAM) as the primary gene induced by Wnt5a. ALCAM was expressed in 69% of Wnt5a-positive but only 27% of Wnt5a-negative cancers (κ = 0.444; P < 0.001). The inhibition of ALCAM reversed the enhanced migratory effect of Wnt5a, confirming the importance of this protein in the migration of ER-positive breast cancer cells. Wnt5a expression is related to high malignancy and a poor prognosis in ER-positive breast cancer. We suspect that Wnt5a expression increases the malignancy of breast cancer by increasing the migratory capacity of cancer cells through the induction of ALCAM expression.

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.

Integrated diagnostic network construction reveals a 4-gene panel and 5 cancer hallmarks driving breast cancer heterogeneity

Breast cancer encompasses a group of heterogeneous diseases, each associated with distinct clinical implications. Dozens of molecular biomarkers capable of categorizing tumors into clinically relevant subgroups have been proposed which, though considerably contribute in precision medicine, complicate our understandings toward breast cancer subtyping and its clinical translation. To decipher the networking of markers with diagnostic roles on breast carcinomas, we constructed the diagnostic networks by incorporating 6 publically available gene expression datasets with protein interaction data retrieved from BioGRID on previously identified 1015 genes with breast cancer subtyping roles. The Greedy algorithm and mutual information were used to construct the integrated diagnostic network, resulting in 37 genes enclosing 43 interactions. Four genes, FAM134B, KIF2C, ALCAM, KIF1A, were identified having comparable subtyping efficacies with the initial 1015 genes evaluated by hierarchical clustering and cross validations that deploy support vector machine and k nearest neighbor algorithms. Pathway, Gene Ontology, and proliferation marker enrichment analyses collectively suggest 5 primary cancer hallmarks driving breast cancer differentiation, with those contributing to uncontrolled proliferation being the most prominent. Our results propose a 37-gene integrated diagnostic network implicating 5 cancer hallmarks that drives breast cancer heterogeneity and, in particular, a 4-gene panel with clinical diagnostic translation potential.

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.

Key Factors in Breast Cancer Dissemination and Establishment at the Bone: Past, Present and Future Perspectives

Bone metastases associated with breast cancer remain a clinical challenge due to their associated morbidity, limited therapeutic intervention and lack of prognostic markers. With a continually evolving understanding of bone biology and its dynamic microenvironment, many potential new targets have been proposed. In this chapter, we discuss the roles of well-established bone markers and how their targeting, in addition to tumour-targeted therapies, might help in the prevention and treatment of bone metastases. There are a vast number of bone markers, of which one of the best-known families is the bone morphogenetic proteins (BMPs). This chapter focuses on their role in breast cancer-associated bone metastases, associated signalling pathways and the possibilities for potential therapeutic intervention. In addition, this chapter provides an update on the role receptor activator of nuclear factor-κB (RANK), RANK ligand (RANKL) and osteoprotegerin (OPG) play on breast cancer development and their subsequent influence during the homing and establishment of breast cancer-associated bone metastases. Beyond the well-established bone molecules, this chapter also explores the role of other potential factors such as activated leukocyte cell adhesion molecule (ALCAM) and its potential impact on breast cancer cells' affinity for the bone environment, which implies that ALCAM could be a promising therapeutic target.

Stromal expression of ALDH1 in human breast carcinomas indicates reduced tumor progression

Interactions between cancer cells and microenvironment are emerging issue in tumor progression. Aldehyde dehydrogenase 1 (ALDH1) is a recognized cancer stem cell marker but little is known about its role in intratumoral stroma. Therefore, we focused on ALDH1 expression in tumor-associated stroma of breast carcinomas (BrCa).

Stromal and tumoral ALDH1 expression was evaluated immunohistochemically in BrCa and their lymph node metastases (LNMs), and related to clinico-pathological characteristics, patients’ outcome, presence of CD68, HLADR, retinoic acid (RA) in stroma, and selected proteins in tumor cells.

ALDH1(+) stromal cells were detected in 53% of 374 BrCa and 61% of 102 LNMs. ALDH1(+) stroma in primary tumor correlated to longer disease-free (p = 0.030), metastasis-free (p = 0.024), and overall survival (p = 0.043) having an independent prognostic impact on DFS (multivariate analysis, p = 0.047). It was associated with concomitant presence of HLA-DR(+) stromal cells and RA in tumor cells (both p < 0.001), and inversely associated with vimentin expression in tumor cells (p = 0.036). ALDH1(+) stroma in LNMs correlated inversely to presence of disseminated tumor cells in patients’ bone marrow (p = 0.014) and was independent prognosticator of shorter DFS and MFS (multivariate analysis, p = 0.004 and p = 0.002, respectively).

In conclusion, ALDH1 expression in tumor-associated stromal cells indicates reduced BrCa progression, possibly via RA secretion.

Chromatin immunoprecipitation-sequencing predicts p300 binding sites in the MCF7 human breast cancer cell line

The aim of the present study was to identify the distribution characters of p300 binding sites in estradiol (E2) stimulated MCF7 cell lines and controls, and to study the roles of transcriptional coactivator p300 in the tumorigenesis and progression of various human cancers following E2 stimulation. The chromatin immunoprecipitation followed by sequencing data of GSES9623 was downloaded from the Gene Expression Omnibus database, including breast cancer data of GSM986085 and control data of GSM986087. MACS peak‑calling software was employed to identify the p300‑bound sites in the two groups. The differential target genes of p300‑bound sites were further analyzed and the concordant factors were predicted. The Gene Ontology (GO) was used to conduct functional enrichment analysis. There were 32,249 p300 binding sites identified in the E2 stimulation group and 43,156 in the control group. GO enrichment analysis of the target genes showed that p300‑regulated target genes mainly participated in the neural cell differentiation‑associated biology process; while in the E2 stimulation group, partial functions of the target genes had changed. A total of 24,899 differential p300‑bound sites of the two groups were identified and GO enrichment analysis demonstrated that E2 stimulation changed p300 binding sites, but did not influence the regulatory function of p300. The effect of E2 in the MCF7 cells suggested that E2 affected the binding affinity of DNA and transcription factors in a large scale. By analyzing the concordant factors, several important factors were discovered, such as BRCA1 and ESR1. Overall, the results of the present study suggested an association between p300 and carcinogenic genes. This may provide theoretical guidance for cancer therapy.

Loss of CADM1 expression is associated with poor prognosis and brain metastasis in breast cancer patients

Breast cancer brain metastases (BCBM) are detected with increasing incidence. In order to detect potential genes involved in BCBM, we first screened for genes down-regulated by methylation in cell lines with site-specific metastatic ability. The expression of five genes, CADM1, SPARC, RECK, TNFAIP3 and CXCL14, which were also found down-regulated in gene expression profiling analyses of BCBM tissue samples, was verified by qRT-PCR in a larger patient cohort. CADM1 was chosen for further down-stream analyses. A higher incidence of CADM1 methylation, correlating with lower expression levels, was found in BCBM as compared to primary BC. Loss of CADM1 protein expression was detected most commonly among BCBM samples as well as among primary tumors with subsequent brain relapse. The prognostic role of CADM1 expression was finally verified in four large independent breast cancer cohorts (n=2136). Loss of CADM1 protein expression was associated with disease stage, lymph node status, and tumor size in primary BC. Furthermore, all analyses revealed a significant association between loss of CADM1 and shorter survival. In multivariate analyses, survival was significantly shorter among patients with CADM1-negative tumors. Loss of CADM1 expression is an independent prognostic factor especially associated with the development of brain metastases in breast cancer patients.

Overexpression of activated leukocute cell adhesion molecule in gastric cancer is associated with advanced stages and poor prognosis and miR-9 deregulation

Activated leukocyte cell adhesion molecule (ALCAM) has been identified as a novel potential molecular marker of human tumors. The present study aimed to assess ALCAM as a prognostic marker for gastric cancer (GC), and to explore the mRNA deregulation underlying the abnormal expression of ALCAM. The mRNA and protein expression of ALCAM in GC and adjacent non‑tumor tissues from 66 patients with GC were analyzed. The association between miR‑9 and ALCAM mRNA expression was determined by quantitative polymerase chain reaction. Serum soluble ALCAM (sALCAM) was analyzed by ELISA in 72 patients with GC, 82 patients with gastric precancerous lesions and 73 controls. ALCAM and sALCAM levels were associated with certain clinicopathological variables, including overall survival. Compared with the non‑tumor tissues, the expression of ALCAM mRNA in the GC tissues was significantly upregulated (P=0.013). The expression of miR‑9 was reduced and inversely correlated with ALCAM mRNA levels in GC tissues and cell lines. The ALCAM mRNA level was reduced following ectopic overexpression of miR‑9 in SGC‑7901 human gastric cancer cells. The rates of membranous and cytoplasmic expression of ALCAM in GC tissues were 59.1 and 48.48%, respectively, and the serum sALCAM levels were significantly elevated in patients with GC. Elevated ALCAM mRNA, membranous ALCAM expression in GC tissues and high sALCAM levels are associated with advanced tumor stage, lymphatic invasion and shorter overall survival duration. The results of the current study indicated that membranous ALCAM expression and high serum sALCAM levels are independent prognostic markers of poor survival for patients with GC, and that the overexpression of ALCAM may be due to the downregulation of miR‑9.

MiR-378 as a biomarker for response to anti-angiogenic treatment in ovarian cancer

OBJECTIVE

To determine the role of miR-378 as a biomarker for anti-angiogenic therapy response in ovarian cancer.

METHODS

Expression of miR-378 was analyzed in ovarian cancer cell lines and human tumors vs. normal ovarian epithelial cells by qRT-PCR. After miR-378 transfection in SKOV3 cells, dysregulated genes were identified using microarray. Data from The Cancer Genome Atlas (TCGA) was utilized to correlate miR-378 expression with progression-free survival (PFS) among patients treated with anti-angiogenic therapy by using Kaplan-Meier and Cox proportional hazards.

RESULTS

MiR-378 was overexpressed in ovarian cancer cells and tumors vs. normal ovarian epithelial cells. Overexpressing miR-378 in ovarian cancer cells altered expression of genes associated with angiogenesis (ALCAM, EHD1, ELK3, TLN1), apoptosis (RPN2, HIPK3), and cell cycle regulation (SWAP-70, LSM14A, RDX). In the TCGA dataset, low vs. high miR-378 expression was associated with longer PFS in a subset of patients with recurrent ovarian cancer treated with bevacizumab (9.2 vs. 4.2months; p=0.04). On multivariate analysis, miR-378 expression was an independent predictor for PFS after anti-angiogenic treatment (HR=2.04, 95% CI: 1.12-3.72; p=0.02). Furthermore, expression levels of two miR-378 targets (ALCAM and EHD1) were associated with PFS in this subgroup of patients who received anti-angiogenic therapy (9.4 vs. 4.2months, p=0.04 for high vs. low ALCAM; 7.9 vs. 2.3months, p<0.01 for low vs. high EHD1).

CONCLUSIONS

Our data suggest that miR-378 is overexpressed in ovarian cancer cells and tumors vs. normal ovarian epithelial cells. MiR-378 and its downstream targets may serve as markers for response to anti-angiogenic therapy.

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.

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.

Integrative analysis of multiple cancer prognosis studies with gene expression measurements

Although in cancer research microarray gene profiling studies have been successful in identifying genetic variants predisposing to the development and progression of cancer, the identified markers from analysis of single datasets often suffer low reproducibility. Among multiple possible causes, the most important one is the small sample size hence the lack of power of single studies. Integrative analysis jointly considers multiple heterogeneous studies, has a significantly larger sample size, and can improve reproducibility. In this article, we focus on cancer prognosis studies, where the response variables are progression-free, overall, or other types of survival. A group minimax concave penalty (GMCP) penalized integrative analysis approach is proposed for analyzing multiple heterogeneous cancer prognosis studies with microarray gene expression measurements. An efficient group coordinate descent algorithm is developed. The GMCP can automatically accommodate the heterogeneity across multiple datasets, and the identified markers have consistent effects across multiple studies. Simulation studies show that the GMCP provides significantly improved selection results as compared with the existing meta-analysis approaches, intensity approaches, and group Lasso penalized integrative analysis. We apply the GMCP to four microarray studies and identify genes associated with the prognosis of breast cancer.