CD166/activated leukocyte cell adhesion molecule is expressed on glioblastoma progenitor cells and involved in the regulation of tumor cell invasion

The efficacy and applicability of chimeric antigen receptor (CAR) T cell-based regimens for primary bone tumors: A comprehensive review of current evidence

Primary bone tumors (PBT), although rare, could pose significant mortality and morbidity risks due to their high incidence of lung metastasis. Survival rates of patients with PBTs may vary based on the tumor type, therapeutic interventions, and the time of diagnosis. Despite advances in the management of patients with these tumors over the past four decades, the survival rates seem not to have improved significantly, implicating the need for novel therapeutic interventions. Surgical resection with wide margins, radiotherapy, and systemic chemotherapy are the main lines of treatment for PBTs. Neoadjuvant and adjuvant chemotherapy, along with emerging immunotherapeutic approaches such as chimeric antigen receptor (CAR)-T cell therapy, have the potential to improve the treatment outcomes for patients with PBTs. CAR-T cell therapy has been introduced as an option in hematologic malignancies, with FDA approval for several CD19-targeting CAR-T cell products. This review aims to highlight the potential of immunotherapeutic strategies, specifically CAR T cell therapy, in managing PBTs.

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.

Overall review of curative impact and barriers of CAR-T cells in osteosarcoma

Osteosarcoma (OS) is a rare form of cancer and primary bone malignancy in children and adolescents. Current therapies include surgery, chemotherapy, and amputation. Therefore, a new therapeutic strategy is needed to dramatically change cancer treatment. Recently, chimeric antigen receptor T cells (CAR-T cells) have been of considerable interest as it has provided auspicious results and patients suffering from low side effects after injection that resolve with current therapy. However, there are reports that cytokine release storm (CRS) can be observed in some patients. In addition, as researchers have faced problems that limit and suppress T cells, further studies are required to resolve these problems. In addition, to maximize the therapeutic benefit of CAR-T cell therapy, researchers have suggested that combination therapy could be better used to treat cancer by overcoming any problems and reducing side effects as much as possible. This review summarizes these problems, barriers, and the results of some studies on the evaluation of CAR-T cells in patients with osteosarcoma.

The Putative S1PR1 Modulator ACT-209905 Impairs Growth and Migration of Glioblastoma Cells In Vitro

Glioblastoma (GBM) is still a deadly tumor due to its highly infiltrative growth behavior and its resistance to therapy. Evidence is accumulating that sphingosine-1-phosphate (S1P) acts as an important tumor-promoting molecule that is involved in the activation of the S1P receptor subtype 1 (S1PR1). Therefore, we investigated the effect of ACT-209905 (a putative S1PR1 modulator) on the growth of human (primary cells, LN-18) and murine (GL261) GBM cells. The viability and migration of GBM cells were both reduced by ACT-209905. Furthermore, co-culture with monocytic THP-1 cells or conditioned medium enhanced the viability and migration of GBM cells, suggesting that THP-1 cells secrete factors which stimulate GBM cell growth. ACT-209905 inhibited the THP-1-induced enhancement of GBM cell growth and migration. Immunoblot analyses showed that ACT-209905 reduced the activation of growth-promoting kinases (p38, AKT1 and ERK1/2), whereas THP-1 cells and conditioned medium caused an activation of these kinases. In addition, ACT-209905 diminished the surface expression of pro-migratory molecules and reduced CD62P-positive GBM cells. In contrast, THP-1 cells increased the ICAM-1 and P-Selectin content of GBM cells which was reversed by ACT-209905. In conclusion, our study suggests the role of S1PR1 signaling in the growth of GBM cells and gives a partial explanation for the pro-tumorigenic effects that macrophages might have on GBM cells.

WDR5 represents a therapeutically exploitable target for cancer stem cells in glioblastoma

Glioblastomas (GBMs) are heterogeneous, treatment-resistant tumors driven by populations of cancer stem cells (CSCs). However, few molecular mechanisms critical for CSC population maintenance have been exploited for therapeutic development. We developed a spatially resolved loss-of-function screen in GBM patient-derived organoids to identify essential epigenetic regulators in the SOX2-enriched, therapy-resistant niche and identified WDR5 as indispensable for this population. WDR5 is a component of the WRAD complex, which promotes SET1 family-mediated Lys4 methylation of histone H3 (H3K4me), associated with positive regulation of transcription. In GBM CSCs, WDR5 inhibitors blocked WRAD complex assembly and reduced H3K4 trimethylation and expression of genes involved in CSC-relevant oncogenic pathways. H3K4me3 peaks lost with WDR5 inhibitor treatment occurred disproportionally on POU transcription factor motifs, including the POU5F1(OCT4)::SOX2 motif. Use of a SOX2/OCT4 reporter demonstrated that WDR5 inhibitor treatment diminished cells with high reporter activity. Furthermore, WDR5 inhibitor treatment and WDR5 knockdown altered the stem cell state, disrupting CSC in vitro growth and self-renewal, as well as in vivo tumor growth. These findings highlight the role of WDR5 and the WRAD complex in maintaining the CSC state and provide a rationale for therapeutic development of WDR5 inhibitors for GBM and other advanced cancers.

α2,6 Sialylation mediated by ST6GAL1 promotes glioblastoma growth

One of the least-investigated areas of brain pathology research is glycosylation, which is a critical regulator of cell surface protein structure and function. β-Galactoside α2,6-sialyltransferase (ST6GAL1) is the primary enzyme that α2,6 sialylates N-glycosylated proteins destined for the plasma membrane or secretion, thereby modulating cell signaling and behavior. We demonstrate a potentially novel, protumorigenic role for α2,6 sialylation and ST6GAL1 in the deadly brain tumor glioblastoma (GBM). GBM cells with high α2,6 sialylation exhibited increased in vitro growth and self-renewal capacity and decreased mouse survival when orthotopically injected. α2,6 Sialylation was regulated by ST6GAL1 in GBM, and ST6GAL1 was elevated in brain tumor-initiating cells (BTICs). Knockdown of ST6GAL1 in BTICs decreased in vitro growth, self-renewal capacity, and tumorigenic potential. ST6GAL1 regulates levels of the known BTIC regulators PDGF Receptor β (PDGFRB), Activated Leukocyte Cell Adhesion Molecule, and Neuropilin, which were confirmed to bind to a lectin-recognizing α2,6 sialic acid. Loss of ST6GAL1 was confirmed to decrease PDGFRB α2,6 sialylation, total protein levels, and the induction of phosphorylation by PDGF-BB. Thus, ST6GAL1-mediated α2,6 sialylation of a select subset of cell surface receptors, including PDGFRB, increases GBM growth.

Glioblastoma microenvironment contains multiple hormonal and non-hormonal growth-stimulating factors

Background

The growth of malignant tumors is influenced by their microenvironment. Glioblastoma, an aggressive primary brain tumor, may have cysts containing fluid that represents the tumor microenvironment. The aim of this study was to investigate whether the cyst fluid of cystic glioblastomas contains growth-stimulating factors. Identification of such growth factors may pave the way for the development of targeted anti-glioblastoma therapies.

Methods

We performed hormone analysis of cyst fluid from 25 cystic glioblastomas and proteomics analysis of cyst fluid from another 12 cystic glioblastomas.

Results

Glioblastoma cyst fluid contained hormones within wide concentration ranges: Insulin-like growth factor 1 (0–13.7 nmol/L), insulin (1.4–133 pmol/L), erythropoietin (4.7–402 IU/L), growth hormone (0–0.93 µg/L), testosterone (0.2–10.1 nmol/L), estradiol (0–1.0 nmol/L), triiodothyronine (1.0–11.5). Tumor volume correlated with cyst fluid concentrations of growth hormone and testosterone. Survival correlated inversely with cyst fluid concentration of erythropoietin. Several hormones were present at concentrations that have been shown to stimulate glioblastoma growth in vitro. Concentrations of erythropoietin and estradiol (in men) were higher in cyst fluid than in serum, suggesting formation by tumor or brain tissue. Quantitatively, glioblastoma cyst fluid was dominated by serum proteins, illustrating blood–brain barrier leakage. Proteomics identified several proteins that stimulate tumor cell proliferation and invasiveness, others that inhibit apoptosis or mediate adaption to hypoxia and some that induce neovascularization or blood–brain barrier leakage.

Conclusion

The microenvironment of glioblastomas is rich in growth-stimulating factors that may originate from the circulation, the tumor, or the brain. The wide variation in cyst fluid hormone concentrations may differentially influence tumor growth.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12987-022-00333-z.

Landscape of surfaceome and endocytome in human glioma is divergent and depends on cellular spatial organization

Cancer immunotherapies, including checkpoint inhibitor blocking antibodies and antibody drug conjugates, currently revolutionize cancer treatment. However, a remaining challenge is the identification of tumor surfaceome (TS) targets for the design of more rational, individualized treatments. We have developed a procedure for unbiased mapping of TS targets in glioblastoma (GBM), i.e., the most common primary malignant brain tumor that remains among the most aggressive forms of cancer, and for which attempts to find effective treatments have failed so far. The present study provides additional layers of understanding fundamental to the future development of immunotherapy strategies, as well as procedures for proteomics-based target identification aimed at a better understanding of how to harness the TS for personalized immunotherapy.

Therapeutic strategies directed at the tumor surfaceome (TS), including checkpoint inhibitor blocking antibodies, antibody drug conjugates (ADCs), and chimeric antigen receptor T (CAR-T) cells, provide a new armament to fight cancer. However, a remaining bottleneck is the lack of strategies to comprehensively interrogate patient tumors for potential TS targets. Here, we have developed a platform (tumor surfaceome mapping [TS-MAP]) integrated with a newly curated TS classifier (SURFME) that allows profiling of primary 3D cultures and intact patient glioma tumors with preserved tissue architecture. Moreover, TS-MAP specifically identifies proteins capable of endocytosis as tractable targets for ADCs and other modalities requiring toxic payload internalization. In high-grade gliomas that remain among the most aggressive forms of cancer, we show that cellular spatial organization (2D vs. 3D) fundamentally transforms the surfaceome and endocytome (e.g., integrins, proteoglycans, semaphorins, and cancer stem cell markers) with general implications for target screening approaches, as exemplified by an ADC targeting EGFR. The TS-MAP platform was further applied to profile the surfaceome and endocytome landscape in a cohort of freshly resected gliomas. We found a highly diverse TS repertoire between patient tumors, not directly associated with grade and histology, which highlights the need for individualized approaches. Our data provide additional layers of understanding fundamental to the future development of immunotherapy strategies, as well as procedures for proteomics-based target identification and selection. The TS-MAP platform should be widely applicable in efforts aiming at a better understanding of how to harness the TS for personalized immunotherapy.

Activated leukocyte cell adhesion molecule (ALCAM)/CD166 in pancreatic cancer, a pivotal link to clinical outcome and vascular embolism

Activated leukocyte cell adhesion molecule (ALCAM, or CD166) is a cell adhesion molecule and one of potential tumour metastasis 'soil' receptors that via homotypic and heterotypic interactions, mediates cancer cell adhesion. The present study investigated clinical, pathological and prognostic values of ALCAM in patients with pancreatic cancer. Human pancreatic cancer (PANC-1 and Mia PaCa-2) and human vascular endothelial cell lines were used to construct cell models differentially expressing levels of ALCAM. Tumour-endothelial interaction and tumour migration were assessed by a DiI-based method and electric cell-substrate impedance sensing (ECIS) assay. Pancreatic cancer tissues (n=223), collected immediately after surgery, were analysed for levels of the ALCAM transcripts, which were also analysed against clinical, pathological and clinical outcomes of the patients. ALCAM protein was assessed by immunohistochemistry on a tissue array. Our study demonstrate that pancreatic cancer tissues had significantly higher levels of ALCAM transcripts than normal tissues (P<0.00001). There were no significant differences with staging, differentiation and tumour locations. Tumours from patients who died of pancreatic cancer had significantly high levels of ALCAM compared with those who lived (P=0.018), and this finding was further supported by ROC analysis (P=0.016). Multivariant analysis showed that ALCAM is an independent prognosis factor for overall survival (HR=5.485), with both nodal status and TNM staging contributing to the model (HR=2.578 and 3.02, respectively). A surprising finding was the relationship between ALCAM expression and microvessel embolism of tumour cells (P=0.021, with vs without tumour embolism). Levels of ALCAM were found to be a determinant factor to adherence of the pancreatic cancer cells to vascular endothelial cells, as demonstrated by pancreatic cancer cell models genetically engineered to express differential levels of ALCAM. The tumour-endothelial interaction mediated by ALCAM was readily blocked by addition of soluble ALCAM. Our data supports the conclusion that ALCAM expression is aberrant in pancreatic cancer and its raised expression is an independent prognostic factor for the survival of the patients and the microvascular embolism by cancer cells. Our results suggest that ALCAM plays a key role in mediating tumour-endothelial cell interactions and enhancing tumour embolism in pancreatic cancer, and targeting ALCAM represents a potential therapeutic strategy for treating human pancreatic cancer.

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.

Chimeric Antigen Receptor T-Cell Therapy: The Light of Day for Osteosarcoma

Simple Summary

As a novel immunotherapy, chimeric antigen receptor (CAR) T-cell therapy has achieved encouraging results in leukemia and lymphoma. Furthermore, CAR-T cells have been explored in the treatment of osteosarcoma (OS). However, there is no strong comprehensive evidence to support their efficacy. Therefore, we reviewed the current evidence on CAR-T cells for OS to demonstrate their feasibility and provide new options for the treatment of OS.

Abstract

Osteosarcoma (OS) is the most common malignant bone tumor, arising mainly in children and adolescents. With the introduction of multiagent chemotherapy, the treatments of OS have remarkably improved, but the prognosis for patients with metastases is still poor, with a five-year survival rate of 20%. In addition, adverse effects brought by traditional treatments, including radical surgery and systemic chemotherapy, may seriously affect the survival quality of patients. Therefore, new treatments for OS await exploitation. As a novel immunotherapy, chimeric antigen receptor (CAR) T-cell therapy has achieved encouraging results in treating cancer in recent years, especially in leukemia and lymphoma. Furthermore, researchers have recently focused on CAR-T therapy in solid tumors, including OS. In this review, we summarize the safety, specificity, and clinical transformation of the targets in treating OS and point out the direction for further research.

A novel molecular magnetic resonance imaging agent targeting activated leukocyte cell adhesion molecule as demonstrated in mouse brain metastasis models

Molecular magnetic resonance imaging (MRI) allows visualization of biological processes at the molecular level. Upregulation of endothelial ALCAM (activated leukocyte cell adhesion molecule) is a key element for leukocyte recruitment in neurological disease. The aim of this study, therefore, was to develop a novel molecular MRI contrast agent, by conjugating anti-ALCAM antibodies to microparticles of iron oxide (MPIO), for detection of endothelial ALCAM expression in vivo. Binding specificity of ALCAM-MPIO was demonstrated in vitro under static and flow conditions. Subsequently, in a proof-of-concept study, mouse models of brain metastasis were induced by intracardial injection of brain-tropic human breast carcinoma, lung adenocarcinoma or melanoma cells to upregulate endothelial ALCAM. At selected time-points, mice were injected intravenously with ALCAM-MPIO, and ALCAM-MPIO induced hypointensities were observed on T2*-weighted images in all three models. Post-gadolinium MRI confirmed an intact blood-brain barrier, indicating endoluminal binding. Correlation between endothelial ALCAM expression and ALCAM-MPIO binding was confirmed histologically. Statistical analysis indicated high sensitivity (80-90%) and specificity (79-83%) for detection of endothelial ALCAM in vivo with ALCAM-MPIO. Given reports of endothelial ALCAM upregulation in numerous neurological diseases, this advance in our ability to image ALCAM in vivo may yield substantial improvements for both diagnosis and targeted therapy.

Activated leukocyte cell adhesion molecule expression correlates with the WNT subgroup in medulloblastoma and is involved in regulating tumor cell proliferation and invasion

Cluster of differentiation (CD) 166 or activated leukocyte cell adhesion molecule (ALCAM) is a transmembrane molecule known to be an intercellular adhesion factor. The expression and function of ALCAM in medulloblastoma (MB), a pediatric brain tumor with highly advanced molecular genetics, remains unclear. Therefore, this study aimed to clarify the significance and functional role of ALCAM expression in MB. ALCAM expression in 45 patients with MB was evaluated by immunohistochemical analysis of formalin-fixed paraffin-embedded clinical specimens and the relationship between ALCAM expression and pathological type/molecular subgroup, such as WNT, SHH, Group 3, and Group 4, was examined. Eight ALCAM positive (18%), seven partially positive (16%), and 30 negative (67%) cases were detected. All seven cases of the WNT molecular subgroup were ALCAM positive and ALCAM expression strongly correlated with this subgroup (P < 0.0001). In addition, functional studies using MB cell lines revealed ALCAM expression affected proliferation and migration as a positive regulator in vitro. However, ALCAM silencing did not affect survival or the formation of leptomeningeal dissemination in an orthotopic mouse model, but did induce a malignant phenotype with increased tumor cell invasion at the dissemination sites (P = 0.0029). In conclusion, our results revealed that ALCAM exhibited highly specific expression in the WNT subgroup of MB. Furthermore, we demonstrated that the cell kinetics of MB cell lines can be altered by the expression of ALCAM.

Is There Such a Thing as a Genuine Cancer Stem Cell Marker? Perspectives from the Gut, the Brain and the Dental Pulp

The conversion of healthy stem cells into cancer stem cells (CSCs) is believed to underlie tumor relapse after surgical removal and fuel tumor growth and invasiveness. CSCs often arise from the malignant transformation of resident multipotent stem cells, which are present in most human tissues. Some organs, such as the gut and the brain, can give rise to very aggressive types of cancers, contrary to the dental pulp, which is a tissue with a very remarkable resistance to oncogenesis. In this review, we focus on the similarities and differences between gut, brain and dental pulp stem cells and their related CSCs, placing a particular emphasis on both their shared and distinctive cell markers, including the expression of pluripotency core factors. We discuss some of their similarities and differences with regard to oncogenic signaling, telomerase activity and their intrinsic propensity to degenerate to CSCs. We also explore the characteristics of the events and mutations leading to malignant transformation in each case. Importantly, healthy dental pulp stem cells (DPSCs) share a great deal of features with many of the so far reported CSC phenotypes found in malignant neoplasms. However, there exist literally no reports about the contribution of DPSCs to malignant tumors. This raises the question about the particularities of the dental pulp and what specific barriers to malignancy might be present in the case of this tissue. These notable differences warrant further research to decipher the singular properties of DPSCs that make them resistant to transformation, and to unravel new therapeutic targets to treat deadly tumors.

A novel HDGF-ALCAM axis promotes the metastasis of Ewing sarcoma via regulating the GTPases signaling pathway

Ewing sarcoma (ES) is a type of highly aggressive pediatric tumor in bones and soft tissues and its metastatic spread remains the most powerful predictor of poor outcome. We previously identified that the transcription factor hepatoma-derived growth factor (HDGF) promotes ES tumorigenesis. However, the mechanisms underlying ES metastasis remain unclear. Here, we show that HDGF drives ES metastasis in vitro and in vivo, and HDGF reduces metastasis-free survival (MFS) in two independent large cohorts of human ES patients. Integrative analyses of HDGF ChIP-seq and gene expression profiling in ES cells reveal that HDGF regulates multiple metastasis-associated genes, among which activated leukocyte cell adhesion molecule (ALCAM) emerges as a major HDGF target and a novel metastasis-suppressor in ES. HDGF down-regulates ALCAM, induces expression and activation of the downstream effectors Rho-GTPase Rac1 and Cdc42, and promotes actin cytoskeleton remodeling and cell-matrix adhesion. In addition, repression of ALCAM and activation of Rac1 and Cdc42 are required for the pro-metastatic functions of HDGF in vitro. Moreover, analyses in murine models with ES tumor orthotopic implantation and experimental metastasis, as well as in human ES samples, demonstrate the associations among HDGF, ALCAM, and GTPases expression levels. Furthermore, high HDGF/low ALCAM expression define a subgroup of patients harboring the worst MFS. These findings suggest that the HDGF/ALCAM/GTPases axis represents a promising therapeutic target for limiting ES metastasis.

The Potential Role of Dysfunctions in Neuron-Microglia Communication in the Pathogenesis of Brain Disorders

The bidirectional communication between neurons and microglia is fundamental for the proper functioning of the central nervous system (CNS). Chemokines and clusters of differentiation (CD) along with their receptors represent ligand-receptor signalling that is uniquely important for neuron - microglia communication. Among these molecules, CX3CL1 (fractalkine) and CD200 (OX-2 membrane glycoprotein) come to the fore because of their cell-type-specific localization. They are principally expressed by neurons when their receptors, CX3CR1 and CD200R, respectively, are predominantly present on the microglia, resulting in the specific axis which maintains the CNS homeostasis. Disruptions to this balance are suggested as contributors or even the basis for many neurological diseases. In this review, we discuss the roles of CX3CL1, CD200 and their receptors in both physiological and pathological processes within the CNS. We want to underline the critical involvement of these molecules in controlling neuron - microglia communication, noting that dysfunctions in their interactions constitute a key factor in severe neurological diseases, such as schizophrenia, depression and neurodegeneration-based conditions.

CD166high Uveal Melanoma Cells Represent a Subpopulation With Enhanced Migratory Capacity

Purpose

Cancer stem cells (CSCs) are a subpopulation of cells with the capacity to drive tumor growth. While there is evidence of the existence of CSCs in uveal melanoma (UM), there is no consensus on their defining markers. In this study, we examined putative CSC markers in UM cell lines, primary UM (PUM), and normal choroidal melanocytes (NCM).

Methods

Nonadherent sphere assays were used to assess the tumorigenic potential of 15 PUMs, 8 high (M3) and 7 low (D3) metastatic risk. Flow cytometry was used to compare the expression of CSC markers between 10 PUMs and 4 NCMs, as well as in 8 UM cell lines grown under adherent and nonadherent conditions. Based on the data generated and from TCGA analyses, CD166 was investigated in detail, including its effect on cell migration using a tumor transendothelial migration assay.

Results

M3 PUM had a greater melanosphere-forming efficiency than D3 PUM. CD166 and Nestin expression was upregulated in PUM compared to NCM by flow cytometry. UM cell lines resistant to anoikis had increased levels of CD271, Nestin, and CD166 compared with adherent cells. TCGA analysis showed that patients with higher CD166 expression had a poorer prognosis: this was supported by a Mel270 CD166high subpopulation that had enhanced migratory capabilities compared with CD166low cells. IHC showed that CD166 is expressed in the cytoplasm and cell membrane of PUM cells.

Conclusions

UM contain a population of cells with characteristics of CSCs. In particular, CD166high UM cells appear to represent a subpopulation with enhanced migratory capacity.

Iron (II) Polypyridyl Complexes as Antiglioblastoma Agents to Overcome the Blood-Brain Barrier and Inhibit Cell Proliferation by Regulating p53 and 4E-BP1 Pathways

Background and Purpose: It is urgently required to develop promising candidates to permeate across blood-brain barrier (BBB) efficiently with simultaneous disrupting vasculogenic mimicry capability of gliomas. Previously, a series of iron (II) complexes were synthesized through a modified method. Hence, the aim of this study was to evaluate anticancer activity of Fe(PIP)₃SO₄ against glioma cancer cells. Methods: Cytotoxic effects were determined via MTT assay, and IC₅₀ values were utilized to evaluate the cytotoxicity. Cellular uptake of Fe(PIP)₃SO₄ between U87 and HEB cells was conducted by subtracting content of the complex remaining in the cell culture supernatants. Propidium Iodide (PI)-flow cytometric analysis was used to analyze cell cycle proportion of U87 cells treated with Fe(PIP)₃SO₄. The reactive oxygen species levels induced by Fe(PIP)₃SO₄ were measured by 2'-deoxycoformycin (DCF) probe; ABTS assay was utilized to examine the radical scavenge capacity of Fe(PIP)₃SO₄. To study the bind efficiency to thioredoxin reductase (TrxR), Fe(PIP)₃SO₄ was introduced into solution containing TrxR. To verify if Fe(PIP)₃SO₄ could penetrate BBB, HBMEC/U87 coculture as BBB model was established, and penetrating capability of Fe(PIP)₃SO₄ was tested. In vitro U87 tumor spheroids were formed to test the permeating ability of Fe(PIP)₃SO₄. Acute toxicity and biodistribution of Fe(PIP)₃SO₄ were tested on mice for 72 h. Protein profiles associated with U87 cells treated with Fe(PIP)₃SO₄ were determined by Western blotting analysis. Results: Results showed that Fe(PIP)₃SO₄ could suppress cell proliferation by inducing G2/M phase cycle retardation and apoptotic pathways, which was related with expression of p53 and initiation factor 4E binding protein 1. In addition, Fe complex could suppress cell proliferation by downregulating reactive oxygen species levels via scavenging free radicals and interaction with TrxR. Furthermore, Fe(PIP)₃SO₄ could permeate across BBB and simultaneously inhibited the vasculogenic mimicry-channel of U87 cells, suggesting favorable antiglioblastoma efficacy. Acute toxicity manifested lower degree of the complex compared with cisplatin and temozolomide. Conclusion: Fe(PIP)₃SO₄ exhibited favorable anticancer activity against glioma cells associated with p53 and 4E binding protein 1, accompanied with negligible toxic effects on normal tissues. Herein, Fe(PIP)₃SO₄ could be developed as a promising metal-based chemotherapeutic agent to overcome BBB and antagonize glioblastomas.

Syntenin: PDZ Protein Regulating Signaling Pathways and Cellular Functions

Syntenin is an adaptor-like molecule that has two adjacent tandem postsynaptic density protein 95/Discs large protein/Zonula occludens 1 (PDZ) domains. The PDZ domains of syntenin recognize multiple peptide motifs with low to moderate affinity. Many reports have indicated interactions between syntenin and a plethora of proteins. Through interactions with various proteins, syntenin regulates the architecture of the cell membrane. As a result, increases in syntenin levels induce the metastasis of tumor cells, protrusion along the neurite in neuronal cells, and exosome biogenesis in various cell types. Here, we review the updated data that support various roles for syntenin in the regulation of neuronal synapses, tumor cell invasion, and exosome control.

Establishment and Characterization of a New Triple Negative Breast Cancer Cell Line from an Iranian Breast Cancer Tissue

Breast cancer is the most common malignancy and the leading cause of cancer-related death among women worldwide. The underlying mechanisms for breast cancer development, especially in young women, are not completely understood. Although there are several experimental models to understand the biology of breast cancer such as immortalized cell lines, many of these cell lines have been in culture for decades and most of them have been derived from Caucasians or African-Americans. So, it is required to establish a new cell line derived from primary tumors and Asian women. In this study Pari-Institute for Cancer Research (Pari-ICR) was derived from the primary breast tumor of a 36-years old patient with invasive ductal carcinoma. We characterized the cell line by examining morphology, expression of different markers, and functional profile. Immunocytochemistry showed that this cell line does not express estrogen and progesterone receptors as well as human epidermal growth factor receptor 2 (HER2). Pari-ICR cell line expresses high levels of Vimentin, Ezrin, and S100 but does not express EpCAM, Cytokeratin19, Pan-cytokeratin, Nestin, and Desmin. Its doubling time of Pari-ICR was about 22h and was able to grow as colonies in soft agar. It displayed a higher ability of migration and invasion in comparison with MCF-7 cell line. This breast cancer cell line can serve as a model for understanding the molecular mechanisms of breast carcinogenesis. Moreover, it can be used as an appropriate resource to find novel biomarkers or assess new drugs.

Engineering stem cell cardiac patch with microvascular features representative of native myocardium

The natural myocardium is a highly aligned tissue with an oriented vasculature. Its characteristic cellular as well as nanoscale extracellular matrix (ECM) organization along with an oriented vascular network ensures appropriate blood supply and functional performance. Although significant efforts have been made to develop anisotropic cardiac structure, currently neither an ideal biomaterial nor an effective vascularization strategy to engineer oriented and high-density capillary-like microvessels has been achieved for clinical cardiovascular therapies. A naturally derived oriented ECM nanofibrous scaffold mimics the physiological structure and components of tissue ECM and guides neovascular network formation. The objective of this study was to create an oriented and dense microvessel network with physiological myocardial microvascular features.

METHODS

Highly aligned decellularized human dermal fibroblast sheets were used as ECM scaffold to regulate physiological alignment of microvascular networks by co-culturing human mesenchymal stem cells (hMSCs) and endothelial cells (ECs). The influence of topographical features on hMSC and EC interaction was investigated to understand underlying mechanisms of neovasculature formation.

RESULTS

Results demonstrate that the ECM topography can be translated to ECs via CD166 tracks and significantly improved hMSC-EC crosstalk and vascular network formation. The aligned ECM nanofibers enhanced structure, length, and density of microvascular networks compared to randomly organized nanofibrous ECM. Moreover, hMSC-EC co-culture promoted secretion of pro-angiogenic growth factors and matrix remodeling via metalloprotease-2 (MMP-2) activation, which resulted in highly dense vascular network formation with intercapillary distance (20 μm) similar to the native myocardium.

CONCLUSION

HMSC-EC co-culture on the highly aligned ECM generates physiologically oriented and dense microvascular network, which holds great potential for cardiac tissue engineering.

A homing system targets therapeutic T cells to brain cancer

Successful T cell immunotherapy for brain cancer requires that the T cells can access tumour tissues, but this has been difficult to achieve. Here we show that, in contrast to inflammatory brain diseases such as multiple sclerosis, where endothelial cells upregulate ICAM1 and VCAM1 to guide the extravasation of pro-inflammatory cells, cancer endothelium downregulates these molecules to evade immune recognition. By contrast, we found that cancer endothelium upregulates activated leukocyte cell adhesion molecule (ALCAM), which allowed us to overcome this immune-evasion mechanism by creating an ALCAM-restricted homing system (HS). We re-engineered the natural ligand of ALCAM, CD6, in a manner that triggers initial anchorage of T cells to ALCAM and conditionally mediates a secondary wave of adhesion by sensitizing T cells to low-level ICAM1 on the cancer endothelium, thereby creating the adhesion forces necessary to capture T cells from the bloodstream. Cytotoxic HS T cells robustly infiltrated brain cancers after intravenous injection and exhibited potent antitumour activity. We have therefore developed a molecule that targets the delivery of T cells to brain cancer.

Mesenchymal stem cells enhance tumorigenic properties of human glioblastoma through independent cell-cell communication mechanisms

Mesenchymal stem cells (MSC) display tumor tropism and have been addressed as vehicles for delivery of anti-cancer agents. As cellular components of the tumor microenvironment, MSC also influence tumor progression. However, the contribution of MSC in brain cancer is not well understood since either oncogenic or tumor suppressor effects have been reported for these cells. Here, MSC were found capable of stimulating human Glioblastoma (GBM) cell proliferation through a paracrine effect mediated by TGFB1. Moreover, when in direct cell-cell contact with GBM cells, MSC elicited an increased proliferative and invasive tumor cell behavior under 3D conditions, as well as accelerated tumor development in nude mice, independently of paracrine TGFB1. A secretome profiling of MSC-GBM co-cultures identified 126 differentially expressed proteins and 10 proteins exclusively detected under direct cell-cell contact conditions. Most of these proteins are exosome cargos and are involved in cell motility and tissue development. These results indicate a dynamic interaction between MSC and GBM cells, favoring aggressive tumor cell traits through alternative and independent mechanisms. Overall, these findings indicate that MSC may exert pro-tumorigenic effects when in close contact with tumor cells, which must be carefully considered when employing MSC in targeted cell therapy protocols against cancer.

Introduction to Cancer Stem Cells: Past, Present, and Future

The Cancer Stem Cell (CSC) hypothesis postulates the existence of a small population of cancer cells with intrinsic properties allowing for resistance to conventional radiochemotherapy regiments and increased metastatic potential. Clinically, the aggressive nature of CSCs has been shown to correlate with increased tumor recurrence, metastatic spread, and overall poor patient outcome across multiple cancer subtypes. Traditionally, isolation of CSCs has been achieved through utilization of cell surface markers, while the functional differences between CSCs and remaining tumor cells have been described through proliferation, differentiation, and limiting dilution assays. The generated insights into CSC biology have further highlighted the importance of studying intratumoral heterogeneity through advanced functional assays, including CRISPR-Cas9 screens in the search of novel targeted therapies. In this chapter, we review the discovery and characterization of cancer stem cells populations within several major cancer subtypes, recent developments of novel assays used in studying therapy resistant tumor cells, as well as recent developments in therapies targeted at cancer stem cells.

Identification of Plasma Membrane Glycoproteins Specific to Human Glioblastoma Multiforme Cells Using Lectin Arrays and LC-MS/MS

Glioblastoma, also known as glioblastoma multiforme (GBM), is the most malignant type of brain cancer and has poor prognosis with a median survival of less than one year. While the structural changes of tumor cell surface carbohydrates are known to be associated with invasive behavior of tumor cells, the cell surface glycoproteins to differentiate the low- and high-grade glioma cells can be potential diagnostic markers and therapeutic targets for GBMs. In the present study, lectin arrays consisting of eight lectins were employed to explore cell surface carbohydrate expression patterns on low-grade oligodendroglioma cells (Hs683) and GBM cells (T98G). Griffonia simplicifolia I (GS I) was found to selectively bind to T98G cells and not to Hs683 cells. For identification of the glioblastoma-specific cell surface markers, the glycoproteins from each cell type were captured by a GS I lectin column and analyzed by LC-MS/MS. The identified proteins from the two cell types were quantified using label-free quantitative analysis based on spectral counting. Of cell surface glycoproteins showing significant increases in T98G cells, five proteins were selected for verification of both protein and glycosylation level changes using Western blot and GS I lectin-based immunosorbent assay.

MicroRNA-138 promotes acquired alkylator resistance in glioblastoma by targeting the Bcl-2-interacting mediator BIM

Glioblastoma is the most aggressive brain tumor in adults with a median survival below 12 months in population-based studies. The main reason for tumor recurrence and progression is constitutive or acquired resistance to the standard of care of surgical resection followed by radiotherapy with concomitant and adjuvant temozolomide (TMZ/RT→TMZ). Here, we investigated the role of microRNA (miRNA) alterations as mediators of alkylator resistance in glioblastoma cells. Using microarray-based miRNA expression profiling of parental and TMZ-resistant cultures of three human glioma cell lines, we identified a set of differentially expressed miRNA candidates. From these, we selected miR-138 for further functional analyses as this miRNA was not only upregulated in TMZ-resistant versus parental cells, but also showed increased expression in vivo in recurrent glioblastoma tissue samples after TMZ/RT→TMZ treatment. Transient transfection of miR-138 mimics in glioma cells with low basal miR-138 expression increased glioma cell proliferation. Moreover, miR-138 overexpression increased TMZ resistance in long-term glioblastoma cell lines and glioma initiating cell cultures. The apoptosis regulator BIM was identified as a direct target of miR-138, and its silencing mediated the induced TMZ resistance phenotype. Altered sensitivity to apoptosis played only a minor role in this resistance mechanism. Instead, we identified the induction of autophagy to be regulated downstream of the miR-138/BIM axis and to promote cell survival following TMZ exposure. Our data thus define miR-138 as a glioblastoma cell survival-promoting miRNA associated with resistance to TMZ therapy in vitro and with tumor progression in vivo.

Therapeutic and Diagnostic Antibodies to CD146: Thirty Years of Research on Its Potential for Detection and Treatment of Tumors

CD146 (MCAM, MUC18, S-Endo1) is a transmembrane glycoprotein belonging to both CAM and mucin families. It exists as different splice variants and is cleaved from the membrane by metalloproteases to generate a soluble form. CD146 is expressed by numerous cancer cells as well as being one of the numerous proteins expressed by the vascular endothelium. It has also been identified on smooth muscle cells, pericytes, and some immune cells. This protein was initially described as an actor involved in tumor growth and metastatic dissemination processes. Some recent works highlighted the role of CD146 in angiogenesis. Interestingly, this knowledge allowed the development of therapeutic and diagnostic tools specifically targeting the different CD146 variants. The first anti-CD146 antibody designed to study the function of this molecule, MUC18, was described by the Pr. J.P. Jonhson in 1987. In this review, we will discuss the 30 following years of research focused on the detection, study, and blocking of this protein in physiological and pathological processes.

Nucleolin-targeted selenium nanocomposites with enhanced theranostic efficacy to antagonize glioblastoma

Glioblastoma is considered as the most lethal cancer, due to the inability of chemotherapeutic agents to reach the glioma core as well as the infiltration zone of the invasive glioma cells. Nanotechnology based delivery systems bring new hope to cancer targeted therapy and diagnosis owing to their enhancement of selective cellular uptake and cytotoxicity to cancer cells through various smart designs. We prepared a novel selenium-based composite nanosystem (QDs/Se@Ru(A)) surface functionalized with the AS1411 aptamer and loaded with quantum dots to realize selectivity against glioblastoma and enhance theranostic effects. This cancer targeted nanosystem significantly enhanced the cellular uptake in glioma cells through nucleolin mediated endocytosis, and increased selectivity between cancer and normal cells. The QDs/Se@Ru(A) nanosystem can also be used for spontaneous fluorescence of biological probes to explore their localization in cancer cells, because of the green fluorescent quantum dots loaded into the selenium nanoparticles. QDs/Se@Ru(A) promotes excess reactive oxygen species (ROS) production in glioma cells to induce DNA damage, thus activating diverse downstream signaling pathways, and inhibiting proliferation of U87 cells through the G2/M phase cycle. Thus, this study provides an effective strategy to design a theranostic agent to simultaneously realize cell imaging and therapy for glioblastoma treatment.

Introduction of High Throughput Magnetic Resonance T2-Weighted Image Texture Analysis for WHO Grade 2 and 3 Gliomas

Reports have suggested that tumor textures presented on T2-weighted images correlate with the genetic status of glioma. Therefore, development of an image analyzing framework that is capable of objective and high throughput image texture analysis for large scale image data collection is needed. The current study aimed to address the development of such a framework by introducing two novel parameters for image textures on T2-weighted images, i.e., Shannon entropy and Prewitt filtering. Twenty-two WHO grade 2 and 28 grade 3 glioma patients were collected whose pre-surgical MRI and IDH1 mutation status were available. Heterogeneous lesions showed statistically higher Shannon entropy than homogenous lesions (p = 0.006) and ROC curve analysis proved that Shannon entropy on T2WI was a reliable indicator for discrimination of homogenous and heterogeneous lesions (p = 0.015, AUC = 0.73). Lesions with well-defined borders exhibited statistically higher Edge mean and Edge median values using Prewitt filtering than those with vague lesion borders (p = 0.0003 and p = 0.0005 respectively). ROC curve analysis also proved that both Edge mean and median values were promising indicators for discrimination of lesions with vague and well defined borders and both Edge mean and median values performed in a comparable manner (p = 0.0002, AUC = 0.81 and p < 0.0001, AUC = 0.83, respectively). Finally, IDH1 wild type gliomas showed statistically lower Shannon entropy on T2WI than IDH1 mutated gliomas (p = 0.007) but no difference was observed between IDH1 wild type and mutated gliomas in Edge median values using Prewitt filtering. The current study introduced two image metrics that reflect lesion texture described on T2WI. These two metrics were validated by readings of a neuro-radiologist who was blinded to the results. This observation will facilitate further use of this technique in future large scale image analysis of glioma.

Time-lapse phenotyping of invasive glioma cells ex vivo reveals subtype-specific movement patterns guided by tumor core signaling

The biology of glioblastoma invasion and its mechanisms are poorly understood. We demonstrate using time-lapse microscopy that grafting of glioblastoma (GBM) tumorspheres into rodent brain slices results in experimental ex vivo tumors with invasive properties that recapitulate the invasion observed after orthotopic transplantation into the rodent brain. The migratory movements and mitotic patterns were clearly modified by signals extrinsic to the invading cells. The cells migrated away from the tumorspheres, and removal of the spheres reduced the directed invasive movement. The cell cultures contained different populations of invasive cells that had distinct morphology and invasive behavior patterns. Grafts of the most invasive GBM culture contained 91±8% cells with an invasive phenotype, characterized by small soma with a distinct leading process. Conversely, the majority of cells in less invasive GBM grafts were phenotypically heterogeneous: only 6.3±4.1% of the cells had the invasive phenotype. Grafts of highly and moderately invasive cultures had different proportions of cells that advanced into the brain slice parenchyma during the observation period: 89.2±2.2% and 23.1±6.8%, respectively. In grafts with moderately invasive properties, most of the cells (76.8±6.8%) invading the surrounding brain tissue returned to the tumor bulk or stopped centrifugal migration. Our data suggest that the invasion of individual GBM tumors can be conditioned by the prevalence of a cell fraction with particular invasive morphology and by signaling between the tumor core and invasive cells. These findings can be important for the development of new therapeutic strategies that target the invasive GBM cells.

Tailoring Particle Size of Mesoporous Silica Nanosystem To Antagonize Glioblastoma and Overcome Blood-Brain Barrier

The blood-brain barrier (BBB) is the main bottleneck to prevent some macromolecular substance entering the cerebral circulation, resulting the failure of chemotherapy in the treatment of glioma. Cancer nanotechnology displays potent applications in glioma therapy owing to their penetration across BBB and accumulation into the tumor core. In this study, we have tailored the particle size of mesoporous silica nanoparticles (MSNs) through controlling the hydrolysis rate and polycondensation degree of reactants, and optimized the nanosystem that could effectively penetrate BBB and target the tumor tissue to achieve enhanced antiglioma efficacy. The nanoparticle was conjugated with cRGD peptide to enhance its cancer targeting effect, and then used to load antineoplastic doxorubicin. Therefore, the functionalized nanosystem (DOX@MSNs) selectively recognizes and binds to the U87 cells with higher expression level of ανβ3 integrin, sequentially enhancing the cellular uptake and inhibition to glioma cells, especially the particle size at 40 nm. This particle could rapidly enter cancer cells and was difficult to excrete outside the cells, thus leading to high drug accumulation. Furthermore, DOX@MSNs exhibited much higher selectivity and anticancer activity than free DOX and induced the glioma cells apoptosis through triggering ROS overproduction. Interestingly, DOX@MSNs at about 40 nm exhibited stronger permeability across the BBB, and could disrupt the VM-capability of glioma cells by regulating the expression of E-cadherin, FAK, and MMP-2, thus achieving satisfactory antiglioblastoma efficacy and avoiding the unwanted toxic side effects to normal brain tissue. Taken together, these results suggest that tailoring the particle size of MSNs nanosystem could be an effective strategy to antagonize glioblastoma and overcome BBB.

Extrinsic and Intrinsic Mechanisms by Which Mesenchymal Stem Cells Suppress the Immune System

Mesenchymal stem cells (MSCs) are a group of fibroblast-like multipotent mesenchymal stromal cells that have the ability to differentiate into osteoblasts, adipocytes, and chondrocytes. Recent studies have demonstrated that MSCs possess a unique ability to exert suppressive and regulatory effects on both adaptive and innate immunity in an autologous and allogeneic manner. A vital step in stem cell transplantation is overcoming the potential graft-versus-host disease, which is a limiting factor to transplantation success. Given that MSCs attain powerful differentiation capabilities and also present immunosuppressive properties, which enable them to survive host immune rejection, MSCs are of great interest. Due to their ability to differentiate into different cell types and to suppress and modulate the immune system, MSCs are being developed for treating a plethora of diseases, including immune disorders. Moreover, in recent years, MSCs have been genetically engineered to treat and sometimes even cure some diseases, and the use of MSCs for cell therapy presents new perspectives for overcoming tissue rejection. In this review, we discuss the potential extrinsic and intrinsic mechanisms that underlie MSCs' unique ability to modulate inflammation, and both innate and adaptive immunity.

Activated Leukocyte Cell Adhesion Molecule (ALCAM) in Saudi Breast Cancer Patients as Prognostic and Predictive Indicator

BACKGROUND

Activated leukocyte cell adhesion molecules (ALCAMs) play an essential role in tumor metastasis and are higher in some patients with breast cancer.

AIM

This study aimed to evaluate ALCAM as an early diagnostic biomarker for breast cancer and how it compares with other markers.

SUBJECTS AND METHODS

One-hundred and sixty-one women were selected for this study. They were divided into three groups: Group 1 consisted of 42 healthy individuals (control) while a patients groups divided into two groups according to tumour grade, Group II, Include 58 breast cancer patient’s grade II and Group III, Include 61 patients with grade III of breast cancer. Tumour markers CEA, CA 15-3 and s ALCAM levels were determined and Group 2 consisted of breast cancer patients.

RESULTS

A highly significant elevation was recorded in s ALCAM, CA 15-3 and CEA. Percent change for grade II and grade III were [sALCAM (90, 127)], [CA15-3 (40, 72)] and [CEA (33, 156)]. Operating characteristic (ROC) curves were used to evaluate the diagnostic performance of the biomarkers ALCAM, CA15-3 and CEA with area under the curve (AUC) of (0.99 & 1.0) (AUC 0.947 & 0.99) and (AUC 0.88 & 0.94) for grade II and grade III respectively the incremental values of AUC were statistically highly significant (p < 0.001).

CONCLUSION

It could be concluded that serum ALCAM concentration represents a suitable biomarker for Saudi arabian breast carcinoma with high sensitivity and has the potential to be used as a diagnostic tool comparable to CA15-3 and CEA.

The evidence of glioblastoma heterogeneity

Cancers are composed of heterogeneous combinations of cells that exhibit distinct phenotypic characteristics and proliferative potentials. Because most cancers have a clonal origin, cancer stem cells (CSCs) must generate phenotypically diverse progenies including mature CSCs that can self-renew indefinitely and differentiated cancer cells that possess limited proliferative potential. However, no convincing evidence exists to suggest that only single CSCs are representative of patients' tumors. To investigate the CSCs' diversity, we established 4 subclones from a glioblastoma patient. These subclones were subsequently propagated and analyzed. The morphology, the self-renewal and proliferative capacities of the subclones differed. Fluorescence-activated cell sorting and cDNA-microarray analyses revealed that each subclone was composed of distinct populations of cells. Moreover, the sensitivities of the subclones to an inhibitor of epidermal growth factor receptor were dissimilar. In a mouse model featuring xenografts of the subclones, the progression and invasion of tumors and animal survival were also different. Here, we present clear evidence that a brain tumor contains heterogeneous subclones that exhibit dissimilar morphologies and self-renewal and proliferative capacities. Our results suggest that single cell-derived subclones from a patient can produce phenotypically heterogeneous self-renewing progenies in both in vitro and in vivo settings.

Recruited brain tumor-derived mesenchymal stem cells contribute to brain tumor progression

The identity of the cells that contribute to brain tumor structure and progression remains unclear. Mesenchymal stem cells (MSCs) have recently been isolated from normal mouse brain. Here, we report the infiltration of MSC-like cells into the GL261 murine glioma model. These brain tumor-derived mesenchymal stem cells (BT-MSCs) are defined with the phenotype (Lin-Sca-1+CD9+CD44+CD166+/-) and have multipotent differentiation capacity. We show that the infiltration of BT-MSCs correlates to tumor progression; furthermore, BT-MSCs increased the proliferation rate of GL261 cells in vitro. For the first time, we report that the majority of GL261 cells expressed mesenchymal phenotype under both adherent and sphere culture conditions in vitro and that the non-MSC population is nontumorigenic in vivo. Although the GL261 cell line expressed mesenchymal phenotype markers in vitro, most BT-MSCs are recruited cells from host origin in both wild-type GL261 inoculated into green fluorescent protein (GFP)-transgenic mice and GL261-GFP cells inoculated into wild-type mice. We show the expression of chemokine receptors CXCR4 and CXCR6 on different recruited cell populations. In vivo, the GL261 cells change marker profile and acquire a phenotype that is more similar to cells growing in sphere culture conditions. Finally, we identify a BT-MSC population in human glioblastoma that is CD44+CD9+CD166+ both in freshly isolated and culture-expanded cells. Our data indicate that cells with MSC-like phenotype infiltrate into the tumor stroma and play an important role in tumor cell growth in vitro and in vivo. Thus, we suggest that targeting BT-MSCs could be a possible strategy for treating glioblastoma 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.

CD166/ALCAM expression is characteristic of tumorigenicity and invasive and migratory activities of pancreatic cancer cells

BACKGROUND

CD166, also known as activated leukocyte cell adhesion molecule (ALCAM), is expressed by various cells in several tissues including cancer. However, the role of CD166 in malignant tumors is controversial, especially in pancreatic cancer. This study aimed to clarify the role and significance of CD166 expression in pancreatic cancer.

METHODS

We performed immunohistochemistry and flow cytometry to analyze the expression of CD166 in surgical pancreatic tissues and pancreatic cancer cell lines. The differences between isolated CD166+ and CD166- pancreatic cancer cells were analyzed by invasion and migration assays, and in mouse xenograft models. We also performed quantitative RT-PCR and microarray analyses to evaluate the expression levels of CD166 and related genes in cultured cells.

RESULTS

Immunohistochemistry revealed high expression of CD166 in pancreatic cancer tissues (12.2%; 12/98) compared with that in normal pancreas controls (0%; 0/17) (p = 0.0435). Flow cytometry indicated that CD166 was expressed in 33.8-70.2% of cells in surgical pancreatic tissues and 0-99.5% of pancreatic cancer cell lines. Invasion and migration assays demonstrated that CD166- pancreatic cancer cells showed stronger invasive and migratory activities than those of CD166+ cancer cells (p<0.05). On the other hand, CD166+ Panc-1 cells showed a significantly stronger colony formation activity than that of CD166- Panc-1 cells (p<0.05). In vivo analysis revealed that CD166+ cells elicited significantly greater tumor growth than that of CD166- cells (p<0.05) in both subcutaneous and orthotopic mouse tumor models. mRNA expression of the epithelial-mesenchymal transition activator Zeb1 was over-expressed in CD166- cells (p<0.001). Microarray analysis showed that TSPAN8 and BST2 were over-expressed in CD166+ cells, while BMP7 and Col6A1 were over-expressed in CD166- cells.

CONCLUSIONS

CD166+ pancreatic cancer cells are strongly tumorigenic, while CD166- pancreatic cancer cells exhibit comparatively stronger invasive and migratory activities. These findings suggest that CD166 expression is related to different functions in pancreatic cancer cells.

Targeting tumor invasion: the roles of MDA-9/Syntenin

INTRODUCTION

Melanoma differentiation-associated gene - 9 (MDA-9)/Syntenin has become an increasingly popular focus for investigation in numerous cancertypes. Originally implicated in melanoma metastasis, it has diverse cellular roles and is consistently identified as a regulator of tumor invasion and angiogenesis. As a potential target for inhibiting some of the most lethal aspects of cancer progression, further insight into the function of MDA-9/Syntenin is mandatory.

AREAS COVERED

Recent literature and seminal articles were reviewed to summarize the latest collective understanding of MDA-9/Syntenin's role in normal and cancerous settings. Insights into its participation in developmental processes are included, as is the functional significance of the N- and C-terminals and PDZ domains of MDA-9/Syntenin. Current reports highlight the clinical significance of MDA-9/Syntenin expression level in a variety of cancers, often correlating directly with reduced patient survival. Also presented are assessments of roles of MDA-9/Syntenin in cancer progression as well as its functions as an intracellular adapter molecule.

EXPERT OPINION

Multiple studies demonstrate the importance of MDA-9/Syntenin in tumor invasion and progression. Through the use of novel drug design approaches, this protein may provide a worthwhile therapeutic target. As many conventional therapies do not address, or even enhance, tumor invasion, an anti-invasive approach would be a worthwhile addition in cancer therapy.

VAMP8 facilitates cellular proliferation and temozolomide resistance in human glioma cells

BACKGROUND

Malignant glioma is a common and lethal primary brain tumor in adults. Here we identified a novel oncoprotein, vesicle-associated membrane protein 8 (VAMP8), and investigated its roles in tumorigenisis and chemoresistance in glioma.

METHODS

The expression of gene and protein were determined by quantitative PCR and Western blot, respectively. Histological analysis of 282 glioma samples and 12 normal controls was performed by Pearson's chi-squared test. Survival analysis was performed using the log-rank test and Cox proportional hazards regression. Cell proliferation and cytotoxicity assay were conducted using Cell Counting Kit-8. Autophagy was detected by confocal microscopy and Western blot.

RESULTS

VAMP8 was significantly overexpressed in human glioma specimens and could become a potential novel prognostic and treatment-predictive marker for glioma patients. Overexpression of VAMP8 promoted cell proliferation in vitro and in vivo, whereas knockdown of VAMP8 attenuated glioma growth by arresting cell cycle in the G0/G1 phase. Moreover, VAMP8 contributed to temozolomide (TMZ) resistance by elevating the expression levels of autophagy proteins and the number of autophagosomes. Further inhibition of autophagy via siRNA-mediated knockdown of autophagy-related gene 5 (ATG5) or syntaxin 17 (STX17) reversed TMZ resistance in VAMP8-overexpressing cells, while silencing of VAMP8 impaired the autophagic flux and alleviated TMZ resistance in glioma cells.

CONCLUSION

Our findings identified VAMP8 as a novel oncogene by promoting cell proliferation and therapeutic resistance in glioma. Targeting VAMP8 may serve as a potential therapeutic regimen for the treatment of glioma.

Cancer stem cells: progress and challenges in lung cancer

The identification of a subpopulation of tumor cells with stem cell-like characteristics first in hematological malignancies and later in solid tumors has emerged into a novel field of cancer research. It has been proposed that this aberrant population of cells now called "cancer stem cells" (CSCs) drives tumor initiation, progression, metastasis, recurrence, and drug resistance. CSCs have been shown to have the capacity of self-renewal and multipotency. Adopting strategies from the field of stem cell research has aided in identification, localization, and targeting of CSCs in many tumors. Despite the huge progress in other solid tumors such as brain, breast, and colon cancers no substantial advancements have been made in lung cancer. This is most likely due to the current rudimentary understanding of lung stem cell hierarchy and heterogeneous nature of lung disease. In this review, we will discuss the most recent findings related to identification of normal lung stem cells and CSCs, pathways involved in regulating the development of CSCs, and the importance of the stem cell niche in development and maintenance of CSCs. Additionally, we will examine the development and feasibility of novel CSC-targeted therapeutic strategies aimed at eradicating lung CSCs.

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.

Syntenin-1 and ezrin proteins link activated leukocyte cell adhesion molecule to the actin cytoskeleton

Activated leukocyte cell adhesion molecule (ALCAM) is a type I transmembrane protein member of the immunoglobulin superfamily of cell adhesion molecules. Involved in important pathophysiological processes such as the immune response, cancer metastasis, and neuronal development, ALCAM undergoes both homotypic interactions with other ALCAM molecules and heterotypic interactions with the surface receptor CD6 expressed at the T cell surface. Despite biochemical and biophysical evidence of a dynamic association between ALCAM and the actin cytoskeleton, no detailed information is available about how this association occurs at the molecular level. Here, we exploit a combination of complementary microscopy techniques, including FRET detected by fluorescence lifetime imaging microscopy and single-cell force spectroscopy, and we demonstrate the existence of a preformed ligand-independent supramolecular complex where ALCAM stably interacts with actin by binding to syntenin-1 and ezrin. Interaction with the ligand CD6 further enhances these multiple interactions. Altogether, our results propose a novel biophysical framework to understand the stabilizing role of the ALCAM supramolecular complex engaged to CD6 during dendritic cell-T cell interactions and provide novel information on the molecular players involved in the formation and signaling of the immunological synapse at the dendritic cell side.

Systematic review of protein biomarkers of invasive behavior in glioblastoma

Glioblastoma (GBM) is an aggressive and incurable brain tumor with a grave prognosis. Recurrence is inevitable even with maximal surgical resection, in large part because GBM is a highly invasive tumor. Invasiveness also contributes to the failure of multiple cornerstones of GBM therapy, including radiotherapy, temozolomide chemotherapy, and vascular endothelial growth factor blockade. In recent years there has been significant progress in the identification of protein biomarkers of invasive phenotype in GBM. In this article, we comprehensively review the literature and survey a broad spectrum of biomarkers, including proteolytic enzymes, extracellular matrix proteins, cell adhesion molecules, neurodevelopmental factors, cell signaling and transcription factors, angiogenic effectors, metabolic proteins, membrane channels, and cytokines and chemokines. In light of the marked variation seen in outcomes in GBM patients, the systematic use of these biomarkers could be used to form a framework for better prediction, prognostication, and treatment selection, as well as the identification of molecular targets for further laboratory investigation and development of nascent, directed therapies.

New treatment strategies to eradicate cancer stem cells and niches in glioblastoma

Glioblastoma multiforme (GBM) harbors are not only rapidly dividing cells but also small populations of slowly dividing and dormant cells with tumorigenesity, self-renewal, and multi-lineage differentiation capabilities. Known as glioblastoma stem cells (GSCs), they are resistant to conventional chemo- and radiotherapy and may be a causative factor in recurrence. The treatment outcome in patients with GBM remains unsatisfactory and their mean survival time has not improved sufficiently. We studied clinical evidence and basic research findings to assess the possibility of new treatment strategies that target GSCs and their specific microenvironments (GBM niches) and raise the possibility of adding new treatments to eradicate GSCs and GBM niches.