Clinical implication and mitotic effect of CD44 cleavage in relation to osteopontin/CD44 interaction and dysregulated cell cycle protein in gastrointestinal stromal tumor

Osteopontin promotes infarct repair

Understanding how macrophages promote myocardial repair can help create new therapies for infarct repair. We aimed to determine what mechanisms underlie the reparative properties of macrophages. Cytokine arrays revealed that neonatal cardiac macrophages from the injured neonatal heart secreted high amounts of osteopontin (OPN). In vitro, recombinant OPN stimulated cardiac cell outgrowth, cardiomyocyte (CM) cell-cycle re-entry, and CM migration. In addition, OPN induced nuclear translocation of the cytoplasmatic yes-associated protein 1 (YAP1) and upregulated transcriptional factors and cell-cycle genes. Significantly, by blocking the OPN receptor CD44, we eliminated the effects of OPN on CMs. OPN also activated the proliferation and migration of non-CM cells: endothelial cells and cardiac mesenchymal stromal cells in vitro. Notably, the significant role of OPN in myocardial healing was demonstrated by impaired healing in OPN-deficient neonatal hearts. Finally, in the adult mice, a single injection of OPN into the border of the ischemic zone induced CM cell-cycle re-entry, improved scar formation, local and global cardiac function, and LV remodelling 30 days after MI. In summary, we have shown, for the first time, that recombinant OPN activates cell-cycle re-entry in CMs. In addition, recombinant OPN stimulates multiple cardiac cells and improves scar formation, LV remodelling, and regional and global function after MI. Therefore, we propose OPN as a new cell-free therapy to optimize infarct repair.

Human Malignant Rhabdoid Tumor Antigens as Biomarkers and Potential Therapeutic Targets

INTRODUCTION

Atypical teratoid rhabdoid tumor (ATRT) is a lethal type of malignant rhabdoid tumor in the brain, seen mostly in children under two years old. ATRT is mainly linked to the biallelic inactivation of the SMARCB1 gene. To understand the deadly characteristics of ATRT and develop novel diagnostic and immunotherapy strategies for the treatment of ATRT, this study investigated tumor antigens, such as alpha-fetoprotein (AFP), mucin-16 (MUC16/CA125), and osteopontin (OPN), and extracellular matrix modulators, such as matrix metalloproteinases (MMPs), in different human malignant rhabdoid tumor cell lines. In addition, the roles of MMPs were also examined.

MATERIALS AND METHODS

Five human cell lines were chosen for this study, including two ATRT cell lines, CHLA-02-ATRT and CHLA-05-ATRT; a kidney malignant rhabdoid tumor cell line, G401; and two control cell lines, human embryonic kidney HEK293 and HEK293T. Both ATRT cell lines were treated with a broad-spectrum MMP inhibitor, GM6001, to investigate the effect of MMPs on cell proliferation, viability, and expression of tumor antigens and biomarkers. Gene expression was examined using a reverse transcription polymerase chain reaction (RT-PCR), and protein expression was characterized by immunocytochemistry and flow cytometry.

RESULTS

All the rhabdoid tumor cell lines tested had high gene expression levels of MUC16, OPN, AFP, and MSLN. Low expression levels of neuron-specific enolase (ENO2) by the two ATRT cell lines demonstrated their lack of neuronal genotype. Membrane-type 1 matrix metalloproteinase (MT1-MMP/MMP-14) and tissue inhibitor of metalloproteinases-2 (TIMP-2) were highly expressed in these malignant rhabdoid tumor cells, indicating their invasive phenotypes. GM6001 significantly decreased ATRT cell proliferation and the gene expression of MSLN, OPN, and several mesenchymal markers, suggesting that inhibition of MMPs may reduce the aggressiveness of rhabdoid cancer cells.

CONCLUSION

The results obtained from this study may advance our knowledge of the molecular landscapes of human malignant rhabdoid tumors and their biomarkers for effective diagnosis and treatment. This work analyzed the expression of human malignant rhabdoid tumor antigens that may serve as biomarkers for the development of novel therapeutic strategies, such as cancer vaccines and targeted and immunotherapies targeting osteopontin and mesothelin, for the treatment of patients with ATRT and other malignant rhabdoid tumors.

Osteopontin b and c Splice isoforms in Leukemias and Solid Tumors: Angiogenesis Alongside Chemoresistance

Osteopontin (OPN) is a glycoprotein involved in regulation of various influences on tumor progression, such as cellular proliferation, apoptosis, angiogenesis, and metastasis. Vascular endothelial growth factor (VEGF) is a secreted molecule supporting angiogenesis in various cancers through activation of the PI3K/AKT/ERK1/2 pathway. OPN and VEGF have a number of isoforms with various activities. In spite of the well-defined association between OPN and VEGF isoform expression and cure rate for solid tumors, there is a scarcity of information as to any association in leukemia. Based on the critical role of OPN in cell survival, it seems reasonable to hypothesize that OPN and VEGF isoform expression levels may impact on chemoresistance and relapse in leukemia the same as in solid tumors. Hence, the aim of our review was to explain relationships between OPN and VEGF isoforms and angiogenesis and related pathways in chemoresistance of leukemia and solid tumors. Our findings demonstrated that OPNb and OPNc alongside with VEGF isoforms and other gene pathways are involved in angiogenesis and also might promote chemoresistance and even recurrence in leukemia and solid tumors. To sum up, targeting OPN isoforms, particularly b and c, might be a novel therapeutic strategy for the treatment of leukemia as well as solid tumors.

Dual role of CD44 isoforms in ampullary adenocarcinoma: CD44s predicts poor prognosis in early cancer and CD44ν is an indicator for recurrence in advanced cancer

Background

Although postoperative adjuvant chemoradiotherapies prevent recurrence for some patients with ampullary cancer, the recurrence rate is as high as 29 % in patients with stage I cancer. In an effort to identify predictors of recurrence in patients with ampullary adenocarcinoma, we investigated the clinical value of assessing standard and variant forms of CD44.

Methods

Immunohistochemistry staining and reverse-transcription polymerase chain reaction (RT-PCR) was used to detect standard and variant forms of CD44 in samples of ampullary adenocarcinoma. The cDNA microarray analysis comparing tumors with or without pancreatic invasion was undertaken and analyzed by Ingenuity Pathway Analysis.

Results

The standard CD44 (CD44s) isoform was detected in 76 of 98 patients with ampullary adenocarcinoma, and the negative or weak expression of CD44s was correlated with pancreatic invasion, lymphovascular invasion, advanced stage and bone metastasis. Moderate to dense expression of CD44s was correlated with shorter overall survival in patients with localized cancer (T1 or T2 disease, P = 0.0268). The patients with advanced cancer (T3 or T4 disease) and moderate or dense CD44s expression had a trend toward better survival. Alternative splicing of CD44 was confirmed using RT-PCR, which revealed that the CD44ν3-10 isoform was only expressed in patients with cancer recurrence. Fold change of CD44ν6-10 was also increased. In addition, networks containing CD44, vascular endothelial growth factor (VEGF), epidermal growth factor receptor (EGFR), transforming growth factor-β (TGF-β), matrix metalloproteinase 2 (MMP2), AKT, extracellular signal-regulated protein kinase 1 and 2 (ERK1/2), p38 MAPK, activated protein 1 (AP1)‚ and CTNNB1 were constructed after comparing microarray data from patients with and without pancreatic invasion.

Conclusions

Whereas CD44s functions as tumor-promoting oncoprotein in early localized ampullary adenocarcinoma, CD44 variants are expressed in advanced cancer and patients with recurrence. Regional invasiveness and distant metastasis of ampullary cancer is controlled by a complex interacting network.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-015-1924-3) contains supplementary material, which is available to authorized users.

Osteopontin-CD44 signaling in the glioma perivascular niche enhances cancer stem cell phenotypes and promotes aggressive tumor growth

Stem-like glioma cells reside within a perivascular niche and display hallmark radiation resistance. An understanding of the mechanisms underlying these properties will be vital for the development of effective therapies. Here, we show that the stem cell marker CD44 promotes cancer stem cell phenotypes and radiation resistance. In a mouse model of glioma, Cd44(-/-) and Cd44(+/-) animals showed improved survival compared to controls. The CD44 ligand osteopontin shared a perivascular expression pattern with CD44 and promoted glioma stem cell-like phenotypes. These effects were mediated via the γ-secretase-regulated intracellular domain of CD44, which promoted aggressive glioma growth in vivo and stem cell-like phenotypes via CBP/p300-dependent enhancement of HIF-2α activity. In human glioblastoma multiforme, expression of CD44 correlated with hypoxia-induced gene signatures and poor survival. Altogether, these data suggest that in the glioma perivascular niche, osteopontin promotes stem cell-like properties and radiation resistance in adjacent tumor cells via activation of CD44 signaling.

Anti-apoptotic effects of osteopontin through the up-regulation of Mcl-1 in gastrointestinal stromal tumors

Background

Osteopontin (OPN) is a secreted phosphoprotein expressed by neoplastic cells involved in the malignant potential and aggressive phenotypes of human malignancies, including gastrointestinal stromal tumors (GISTs). Our previous study showed that OPN can promote tumor cell proliferation in GISTs. In this series, we further aim to investigate the effect of OPN on apoptosis in GISTs.

Methods

The expression of apoptotic and anti-apoptotic proteins in response to OPN was evaluated. In vitro effects of OPN against apoptosis in GIST were also assessed. GIST specimens were also used for analyzing protein expression of specific apoptosis-related molecules and their clinicopathologic significance.

Results

Up-regulation of β-catenin and anti-apoptotic proteins Mcl-1 with concomitant suppression of apoptotic proteins in response to OPN was noted. A significant anti-apoptotic effect of OPN on imatinib-induced apoptosis was identified. Furthermore, Mcl-1 overexpression was significantly associated with OPN and β-catenin expression in tumor tissues, as well as worse survival clinically.

Conclusions

Our study identifies anti-apoptotic effects of OPN that, through β-catenin-mediated Mcl-1 up-regulation, significantly antagonized imatinib-induced apoptosis in GISTs. These results provide a potential rationale for therapeutic strategies targeting both OPN and Mcl-1 of the same anti-apoptotic signaling pathway, which may account for resistance to imatinib in GISTs.

Proteomic approach toward personalized sarcoma treatment: lessons from prognostic biomarker discovery in gastrointestinal stromal tumor

Sarcomas range from curable tumors to those causing death via metastasis and recurrence. Thus, there is an urgent need for biomarker identification in order to assess the degree of malignancy, predict prognosis, and evaluate possible therapies. Various proteomic approaches and different clinical materials have been used to this end, and candidate biomarkers have been reported for the different types of sarcomas. However, the sample size used in these biomarker studies was generally insufficient, and thus far, no biomarker has been proved useful in clinics. Given that sarcomas are rare, biomarker validation in this setting is more challenging than in other malignancies. In gastrointestinal stromal tumor, adjuvant therapy has proven to be effective. However, only 40% patients experience metastasis after curative surgery alone, and the rest of the patients may not need adjuvant therapy. Using a proteomic approach, we identified pfetin (potassium channel tetramerization domain containing 12, KCTD 12) as a novel prognostic biomarker for sarcoma, and immunohistochemically confirmed its clinical usefulness by a multiinstitutional validation study. Here, we describe our experience and discuss the critical points in the discovery of this biomarker.

Significance of CD44 expression in head and neck cancer: a systemic review and meta-analysis

BACKGROUND

CD44 has been reported to be involved with tumor growth and metastasis and has also been implicated as a CSC marker in head and neck squamous cell cancer (HNSCC). However, the prognostic value of CD44 still remains controversial; hence, we investigated the correlation between CD44 and the clinicopathological features of HNSCC by meta-analysis.

METHODS

A comprehensive search was performed using PubMed, ISI web of Science and China National Knowledge Infrastructure (CNKI) up to April 2013. Only studies with immunohistochemical staining of HNSCC were considered. Data on TNM classification, tumor grade, disease free survival and 3- or 5-year overall survival rate were extracted.

RESULTS

Thirty studies with 2102 patients met the inclusion criteria for the meta-analysis. Fifteen studies used anti-pan-CD44 antibody, 9 used anti-CD44-v6 antibody, 2 used anti-CD44-v3 and 2 used anti-CD44s antibody, 1 used anti-CD44-v9, and 1 used anti-CD44-v6,-v3 and -v4-5 simultaneously. The total percentage of CD44 expression was 57.8%, with 49.3% in oral cancer patients, 66.4% in pharynx and 54.7% in larynx cancer patients expressing CD44. No significant correlation between clinical features and CD44 expression was revealed for oral cancer patients, but CD44 was shown to be associated with advanced T categories (larynx: RR = 1.33, 95% CI 1.01-1.76; larynx & pharynx RR = 1.21, 95% CI 1.08-1.35), worse N categories (larynx: RR = 2.53, 95% CI 1.99-3.21; larynx & pharynx RR = 1.95, 95% CI 1.35-2.82), higher tumor grades (larynx & pharynx RR = 1.71, 95% CI 1.04-2.79) and 5-year OS rates (larynx: RR = 0.62, 95% CI 0.47-0.83; larynx & pharynx RR = 0.66, 95% CI 0.47-0.94) in patients with laryngeal and pharyngolaryngeal cancer. In stratified analysis, pan-CD44 and CD44-v6 expression were both correlated with 5-year OS rate of patients with laryngeal (CD44: RR = 0.66, 95% CI 0.46-0.95; CD44-v6 RR = 0.53, 95% CI 0.37-0.77) and pharyngolaryngeal cancer (CD44: RR = 0.56, 95% CI 0.34-0.93; CD44-v6 RR = 0.53, 95% CI 0.37-0.77).

CONCLUSIONS

Our analysis suggested that CD44 is related to worse T category, N category, tumor grade and prognosis, in pharyngeal and laryngeal cancer, but no clear association was revealed between CD44 expression and oral cancer.

Isolation and genomic characterization of stem cells in head and neck cancer

BACKGROUND

This study investigated the use of 3 different established cell-sorting strategies to isolate and characterize stem cells from head and neck cancer cell lines.

METHODS

Five low-passage cell lines were subjected to cell sorting based on Hoechst side population, Aldefluor, and CD44 expression. Isolated cell populations were studied for gene expression, radiosensitivity, and chemosensitivity to cisplatin and paclitaxel.

RESULTS

Each sorting method identified a different set of genes associated with different gene ontology categories, with mitosis being the only common category. CD44-associated gene changes were almost exclusively associated with cell cycle and in particular mitosis. There were no significant differences in radiosensitivity or cisplatin sensitivity of stem or non-stem cells, but CD44-isolated stem cells were more resistant to paclitaxel.

CONCLUSIONS

This study suggested that CD44 may be the most promising cell-sorting strategy to isolate and investigate the impact of stem cells in head and neck squamous cell cancer (HNSCC).

Osteopontin expression is an independent adverse prognostic factor in resectable gastrointestinal stromal tumor and its interaction with CD44 promotes tumor proliferation

BACKGROUND

Osteopontin (OPN) is a multifunctional secreted glycophosphoprotein involved in miscellaneous physiologic and pathologic processes and is functionally related to the transmembrane receptor CD44. Although OPN expression has been identified to be associated with poor prognosis in several gastrointestinal malignancies, its expression in gastrointestinal stromal tumor (GIST) has not been thoroughly investigated. This study was designed to evaluate the clinicopathologic significance of OPN expression in patients with resectable GIST.

METHODS

OPN expression was analyzed for its clinicopathologic significance in surgical specimens from 99 patients with resectable GIST by immunohistochemistry. In situ Proximity Ligation Assay was used for examining OPN and CD44 interaction in tumor tissues and GIST cell lines. The in vitro effects of OPN and its interaction with CD44 also were assessed.

RESULTS

Increased OPN expression was a significant poor prognostic factor that independently predicted recurrence and poor disease-free survival in patients with resectable GIST. The interaction of OPN and CD44 was confirmed by their significant correlation in both GIST tumor tissues and cell lines by in situ Proximity Ligation Assay analysis. OPN and its interaction with CD44 were related to increased mitosis and significantly enhanced GIST tumor cell proliferation in vitro.

CONCLUSIONS

Our study identified the clinicopathologic significance and biologic effects of OPN expression in resectable GIST. Increased OPN expression was an independent poor prognostic factor and its interaction with CD44 significantly correlated with increased mitosis as well as in vitro proliferation-promoting effects.