Cooperative roles for emmprin and LYVE-1 in the regulation of chemoresistance for primary effusion lymphoma

Role of lymphatic endothelium specific hyaluronan receptor 1 in virus infection and associated diseases

Lymphatic vessel endothelial hyaluronan receptor 1 (LYVE-1) serves as a prominent marker for lymphatic endothelial cells (LECs) and is pivotal in the process of lymphangiogenesis, a critical factor in cancer development and metastasis. Overexpression of LYVE-1 has been observed in various cancers, where it is recognized as an adverse prognostic indicator. Targeting LYVE-1 has demonstrated inhibitory effects on tumor cell proliferation, migration, and the formation of lymph node metastases both in vitro and in vivo. While extensive research has focused on the role of LYVE-1 in cancer cells, its involvement in virus infection and associated diseases remains largely unexplored. This review consolidates recent findings regarding the expression of LYVE-1 and its functions in lymphangiogenesis during various viral infections and the development of related diseases, with a particular emphasis on Kaposi's sarcoma herpesvirus. Despite the limited available data, it is evident that further studies are essential to comprehensively understand the contribution of LYVE-1 to viral pathogenesis and oncogenesis.

A Single-Center Retrospective Analysis of Kaposi's Sarcoma: Is There a Relationship Between Emmprin/CD147 Expression and Biological Behavior?

OBJECTIVES

Emmprin (CD147/BSG) protein is estimated to play a key role in cell migration and chemoresistance in viral carcinogenesis. However, there are very limited studies investigating the CD147 in the oncogenesis of Kaposi's sarcoma-associated herpesvirus. This study aims to reveal the relationship between CD147 expression with histopathological parameters, disease pattern, and recurrence in Kaposi's sarcoma (KS).

METHODS

The study included 67 patients diagnosed with KS between January 1982 and September 2023. Clinical and histopathological features were analyzed retrospectively. HHV-8, CD31, and CD147 expressions were evaluated by immunohistochemistry.

RESULTS

Sixteen (24%) female and 51 (76%) male patients with median age of 64 (10-86) were included in the study. CD147 was positive in 57 (85%) cases and associated with nodular pattern (P = .001), presence of solid/fibrosarcomatous area (P = .005), and high mitotic activity (P = .035). The disease relapsed in 17 (27%) of the 63 patients with median 2 (0-12) years follow-up. While a 5-year relapse-free survival was 48.5% in the CD147 diffuse positive group, it was 83.4% in focal positive and 100% in negative cases (P = .029).

CONCLUSION

Our study exhibited the relationship between CD147 overexpression and recurrence in KS, but the inhomogeneity of the treatment groups and the small number of patients should also be considered. These findings may provide insight into the pathogenesis of KS and the development of targeted therapies in the future.

Basigin binds bacteria and activates Dorsal signaling to promote antibacterial defense in Penaeus vannamei

The NF-κB pathway plays an important role in immune regulation. Basigin, an immunoglobulin superfamily membrane protein, is involved in the activation of NF-κB. However, its role in NF-κB signaling in response to pathogen infection remains unclear. In this study, we identified the Basigin gene from Pacific white shrimp, Penaeus vannamei, a representative species for studying the innate immune system of invertebrates. Basigin promoted the degradation of the IκB homolog Cactus, facilitated the nuclear translocation of the NF-κB family member Dorsal, and positively regulated the expression of Dorsal pathway downstream antimicrobial peptide genes. Interestingly, recombinant Basigin protein could bind a variety of Gram-positive and Gram-negative bacteria. Silencing of Basigin inhibited the Dorsal signaling activated by V. parahaemolyticus infection and significantly decreased the survival rate of V. parahaemolyticus-infected shrimp. The expression levels of the antimicrobial peptides ALF1 and ALF2 were downregulated, and the phagocytosis of hemocytes was attenuated in Basigin-silenced shrimp. Similar results were observed in shrimp treated with a recombinant extracellular region of the Basigin protein that was able to compete with endogenous Basigin. Therefore, to the best of our knowledge, this study is the first to demonstrate the function of Basigin as a pathogen recognition receptor that activates NF-κB signaling for antibacterial immunity in shrimp.

CD147 Mediates 5-Fluorouracil Resistance in Colorectal Cancer by Reprogramming Glycolipid Metabolism

Chemoresistance against 5-fluorouracil (5-FU) is a major issue for colorectal cancer (CRC) patients. Increasing evidence for the roles of CD147 in glycolipid metabolic reprogramming and chemoresistance of tumor cells has emerged in recent years. However, whether CD147 contributes to 5-FU resistance in CRC and the role of abnormal glycolipid metabolism in this process remain poorly understood. We analyzed CD147 expression in primary tumor samples of CRC patients and found that upregulated CD147 correlated with decreased 5-FU chemosensitivity and an unfavorable prognosis of CRC patients. Moreover, in vivo and in vitro experiments confirmed that CD147 regulates glycolipid metabolism through two separate pathways. Mechanistically, CD147 upregulates HIF-1α-mediated glycolysis by activating the PI3K/AKT/mTOR pathway and CD147 also attenuates PPARα-mediated fatty acid oxidation by activation of the MAPK pathway. Most importantly, we found that CD147 confers 5-FU resistance in CRC via these glycolipid metabolic signatures. Our results demonstrated that CD147 is a potential 5-FU resistance biomarker for CRC patients and a candidate therapeutic target to restore 5-FU sensitivity of 5-FU-resistant CRC by remodeling glycolipid metabolism.

High Levels of Hyaluronic Acid Synthase-2 Mediate NRF2-Driven Chemoresistance in Breast Cancer Cells

Hyaluronic acid (HA), a ligand of CD44, accumulates in some types of tumors and is responsible for tumor progression. The nuclear factor erythroid 2-like 2 (NRF2) regulates cytoprotective genes and drug transporters, which promotes therapy resistance in tumors. Previously, we showed that high levels of CD44 are associated with NRF2 activation in cancer stem like-cells. Herein, we demonstrate that HA production was increased in doxorubicin-resistant breast cancer MCF7 cells (MCF7-DR) via the upregulation of HA synthase-2 (HAS2). HA incubation increased NRF2, aldo-keto reductase 1C1 (AKR1C1), and multidrug resistance gene 1 (MDR1) levels. Silencing of HAS2 or CD44 suppressed NRF2 signaling in MCF7-DR, which was accompanied by increased doxorubicin sensitivity. The treatment with a HAS2 inhibitor, 4-methylumbelliferone (4-MU), decreased NRF2, AKR1C1, and MDR1 levels in MCF7-DR. Subsequently, 4-MU treatment inhibited sphere formation and doxorubicin resistance in MCF7-DR. The Cancer Genome Atlas (TCGA) data analysis across 32 types of tumors indicates the amplification of HAS2 gene is a common genetic alteration and is negatively correlated with the overall survival rate. In addition, high HAS2 mRNA levels are associated with increased NRF2 signaling and poor clinical outcome in breast cancer patients. Collectively, these indicate that HAS2 elevation contributes to chemoresistance and sphere formation capacity of drug-resistant MCF7 cells by activating CD44/NRF2 signaling, suggesting a potential benefit of HAS2 inhibition.

The extracellular matrix of hematopoietic stem cell niches

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Comprehensive overview of different classes of ECM molecules in the HSC niche.

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Overview of current knowledge on role of biophysics of the HSC niche.

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Description of approaches to create artificial stem cell niches for several application.

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Importance of considering ECM in drug development and testing.

Hematopoietic stem cells (HSCs) are the life-long source of all types of blood cells. Their function is controlled by their direct microenvironment, the HSC niche in the bone marrow. Although the importance of the extracellular matrix (ECM) in the niche by orchestrating niche architecture and cellular function is widely acknowledged, it is still underexplored. In this review, we provide a comprehensive overview of the ECM in HSC niches. For this purpose, we first briefly outline HSC niche biology and then review the role of the different classes of ECM molecules in the niche one by one and how they are perceived by cells. Matrix remodeling and the emerging importance of biophysics in HSC niche function are discussed. Finally, the application of the current knowledge of ECM in the niche in form of artificial HSC niches for HSC expansion or targeted differentiation as well as drug testing is reviewed.

Combination of biomarkers for neoadjuvant systemic chemotherapy before cystectomy in patients with urinary bladder cancer

Clinical utility of cisplatin based neoadjuvant chemotherapy (NAC) prior to radical cystectomy is limited because of lack of tools that can guide for a better patient selection. We aim to explore if a combination of biomarkers is superior to a single marker. Pretreatment tumor specimens and clinical data from two randomized trials including 250 patients with T2-T4 urothelial bladder cancer, were used. The information on the expressions on tumor tissue of four biomarkers; CCTα, emmprin, survivin, and BCL-2, detected by immunohistochemistry in our previous studies, was used. Cox proportional hazard models, including treatment-by-biomarker interaction terms, were used to assess the predictive value of the biomarkers for efficacy of NAC on overall survival. CCTα provided predictive information about the efficacy of NAC (interaction P=0.009). None of the other biomarkers provided statistically significant information additional to CCTα. The adjusted hazard ratio for NAC treated versus no-NAC was 0.42 (95% CI: 0.27-0.64) for patients with negative CCTα expression, when adding information about emmprin it decreased to 0.33 (95% CI: 0.19-0.56) for patients with both negative CCTα and emmprin. This corresponds to a decrease in number needed to treat from 4 to 3 patients. The combination of CCTα with survivin or BCL-2 yielded similar results. In a group of patients with muscle invasive bladder cancer a combination of two biomarkers might improve the possibility to identify patients most likely to benefit from the use of NAC. Further studies designed to have sufficient power to detect an interaction effect are needed.

Oncogenic viruses and chemoresistance: What do we know?

Chemoresistance is often referred to as a major leading reason for cancer therapy failure, causing cancer relapse and further metastasis. As a result, an urgent need has been raised to reach a full comprehension of chemoresistance-associated molecular pathways, thereby designing new therapy methods. Many of metastatic tumor masses are found to be related with a viral cause. Although combined therapy is perceived as the model role therapy in such cases, chemoresistant features, which is more common in viral carcinogenesis, often get into way of this kind of therapy, minimizing the chance of survival. Some investigations indicate that the infecting virus dominates other leading factors, i.e., genetic alternations and tumor microenvironment, in development of cancer cell chemoresistance. Herein, we have gathered the available evidence on the mechanisms under which oncogenic viruses cause drug-resistance in chemotherapy.

Developing new ceramide analogs and identifying novel sphingolipid-controlled genes against a virus-associated lymphoma

Primary effusion lymphoma (PEL) is an aggressive malignancy with poor prognosis even under chemotherapy. Kaposi sarcoma-associated herpesvirus (KSHV), one of the human oncogenic viruses, is the principal causative agent. Currently, there is no specific treatment for PEL; therefore, developing new therapies is of great importance. Sphingolipid metabolism plays an important role in determining the fate of tumor cells. Our previous studies have demonstrated that there is a correlation between sphingolipid metabolism and KSHV+ tumor cell survival. To further develop sphingolipid metabolism-targeted therapy, after screening a series of newly synthesized ceramide analogs, here, we have identified compounds with effective anti-PEL activity. These compounds induce significant PEL apoptosis, cell-cycle arrest, and intracellular ceramide production through regulation of ceramide synthesizing or ceramide metabolizing enzymes and dramatically suppress tumor progression without visible toxicity in vivo. These new compounds also increase viral lytic gene expression in PEL cells. Our comparative transcriptomic analysis revealed their mechanisms of action for inducing PEL cell death and identified a subset of novel cellular genes, including AURKA and CDCA3, controlled by sphingolipid metabolism, and required for PEL survival with functional validation. These data provide the framework for the development of promising sphingolipid-based therapies against this virus-associated malignancy.

Roles of Proteoglycans and Glycosaminoglycans in Cancer Development and Progression

The extracellular matrix (ECM) spatiotemporally controls cell fate; however, dysregulation of ECM remodeling can lead to tumorigenesis and cancer development by providing favorable conditions for tumor cells. Proteoglycans (PGs) and glycosaminoglycans (GAGs) are the major macromolecules composing ECM. They influence both cell behavior and matrix properties through direct and indirect interactions with various cytokines, growth factors, cell surface receptors, adhesion molecules, enzymes, and glycoproteins within the ECM. The classical features of PGs/GAGs play well-known roles in cancer angiogenesis, proliferation, invasion, and metastasis. Several lines of evidence suggest that PGs/GAGs critically affect broader aspects in cancer initiation and the progression process, including regulation of cell metabolism, serving as a sensor of ECM's mechanical properties, affecting immune supervision, and participating in therapeutic resistance to various forms of treatment. These functions may be implemented through the characteristics of PGs/GAGs as molecular bridges linking ECM and cells in cell-specific and context-specific manners within the tumor microenvironment (TME). In this review, we intend to present a comprehensive illustration of the ways in which PGs/GAGs participate in and regulate several aspects of tumorigenesis; we put forward a perspective regarding their effects as biomarkers or targets for diagnoses and therapeutic interventions.

Mechanistic Insights into Chemoresistance Mediated by Oncogenic Viruses in Lymphomas

Viral lymphomagenesis induced by infection with oncogenic viruses, such as Kaposi’s sarcoma associated herpesvirus (KSHV), Epstein–Barr virus (EBV) and human T-cell leukemia virus (HTLV-1), represents a group of aggressive malignancies with a diverse range of pathological features. Combined chemotherapy remains the standard of care for these virus-associated lymphomas; however, frequent chemoresistance is a barrier to achieving successful long-term disease-free survival. There is increasing evidence that indicates virus-associated lymphomas display more resistance to cytotoxic chemotherapeutic agents than that observed in solid tumors. Although the tumor microenvironment and genetic changes, such as key oncogene mutations, are closely related to chemoresistance, some studies demonstrate that the components of oncogenic viruses themselves play pivotal roles in the multidrug chemoresistance of lymphoma cells. In this review, we summarize recent advances in the understanding of the mechanisms through which oncogenic viruses mediate lymphoma cell chemoresistance, with a particular focus on KSHV and EBV, two major oncogenic viruses. We also discuss the current challenges to overcome these obstacles in the treatment of virus-associated lymphomas.

CD147 Is a Promising Target of Tumor Progression and a Prognostic Biomarker

Microenvironment plays a crucial role in tumor development and progression. Cancer cells modulate the tumor microenvironment, which also contribute to resistance to therapy. Identifying biomarkers involved in tumorigenesis and cancer progression represents a great challenge for cancer diagnosis and therapeutic strategy development. CD147 is a glycoprotein involved in the regulation of the tumor microenvironment and cancer progression by several mechanisms—in particular, by the control of glycolysis and also by its well-known ability to induce proteinases leading to matrix degradation, tumor cell invasion, metastasis and angiogenesis. Accumulating evidence has demonstrated the role of CD147 expression in tumor progression and prognosis, suggesting it as a relevant tumor biomarker for cancer diagnosis and prognosis, as well as validating its potential as a promising therapeutic target in cancers.

The CD147-HYALURONAN Axis in Cancer

CD147 (basigin; EMMPRIN), hyaluronan, and hyaluronan receptors (e.g., CD44) are intimately involved in several phenomena that underlie malignancy. A major avenue whereby they influence tumor progression is most likely their role in the characteristics of cancer stem cells (CSCs), subpopulations of tumor cells that exhibit chemoresistance, invasiveness, and potent tumorigenicity. Both CD147 and hyaluronan have been strongly implicated in chemoresistance and invasiveness, and may be drivers of CSC characteristics, since current evidence indicates that both are involved in epithelial-mesenchymal transition, a crucial process in the acquisition of CSC properties. Hyaluronan is a prominent constituent of the tumor microenvironment whose interactions with cell surface receptors influence several signaling pathways that lead to chemoresistance and invasiveness. CD147 is an integral plasma membrane glycoprotein of the Ig superfamily and cofactor in assembly and activity of monocarboxylate transporters (MCTs). CD147 stimulates hyaluronan synthesis and interaction of hyaluronan with its receptors, in particular CD44 and LYVE-1, which in turn result in activation of multiprotein complexes containing members of the membrane-type matrix metalloproteinase, receptor tyrosine kinase, ABC drug transporter, or MCT families within lipid raft domains. Multivalent hyaluronan-receptor interactions are essential for formation or stabilization of these lipid raft complexes and for downstream signaling pathways or transporter activities. We conclude that stimulation of hyaluronan-receptor interactions by CD147 and the consequent activities of these complexes may be critical to the properties of CSCs and their role in malignancy. Anat Rec, 2019. © 2019 Wiley Periodicals, Inc.

Cancer Stem Cells: Emergent Nature of Tumor Emergency

A functional analysis of 167 genes overexpressed in Krebs-2 tumor initiating cells was performed. In the first part of the study, the genes were analyzed for their belonging to one or more of the three groups, which represent the three major phenotypic manifestation of malignancy of cancer cells, namely (1) proliferative self-sufficiency, (2) invasive growth and metastasis, and (3) multiple drug resistance. 96 genes out of 167 were identified as possible contributors to at least one of these fundamental properties. It was also found that substantial part of these genes are also known as genes responsible for formation and/or maintenance of the stemness of normal pluri-/multipotent stem cells. These results suggest that the malignancy is simply the ability to maintain the stem cell specific genes expression profile, and, as a consequence, the stemness itself regardless of the controlling effect of stem niches. In the second part of the study, three stress factors combined into the single concept of "generalized cellular stress," which are assumed to activate the expression of these genes, were defined. In addition, possible mechanisms for such activation were identified. The data obtained suggest the existence of a mechanism for the de novo formation of a pluripotent/stem phenotype in the subpopulation of "committed" tumor cells.

CD147 expression is associated with poor overall survival in chemotherapy treated triple-negative breast cancer

AIMS

In breast cancer models, the functional roles of CD147 in proliferation, invasion and treatment resistance have been widely reported. However, there are only a few studies examining the clinicopathological correlation and prognostic relevance of CD147 in breast cancer, especially in relation to breast cancer molecular subtypes.

METHODS

In this study, we analysed CD147 expression in a large cohort of breast cancers, correlating with clinicopathological features and the expression of a comprehensive panel of biomarkers in triple-negative breast cancer (TNBC) and non-TNBC subsets. Its relationship with patients' survival was also analysed.

RESULTS

CD147 was expressed in 11.9%(140/1174) of all cases and in 23.8% (40/168) of TNBC. The expression was associated with tumour histological subtypes (p=0.01) and most commonly seen in carcinoma with medullary features (26.0%). CD147 expression correlated with high tumour grade, presence of necrosis and basal-like breast cancer (BLBC) subtype, high Ki67 and expression of some other basal markers and stem-like markers. CD147 expression was also associated with poor overall survival in chemotherapy treated patients with TNBC.

CONCLUSIONS

CD147 is a putative marker in identifying TNBC or BLBC, and may be useful as a prognosis indicator for patients with TNBC or BLBC post chemotherapy.

Cluster of differentiation 147 mediates chemoresistance in breast cancer by affecting vacuolar H+-ATPase expression and activity

Vacuolar H⁺-ATPase (V-ATPase) serves a key role in adjusting and maintaining the intracellular pH, as well as in regulating the drug resistance of tumor cells. In recent years, the expression level of V-ATPase has been considered to be able to predict the sensitivity of breast cancer cells to chemotherapy drugs. Cluster of differentiation 147 (CD147) is known to serve a key role in the development and progression of breast cancer. The present study aimed to identify the role CD147 and V-ATPase in chemoresistance in breast cancer, and to characterize the regulation of CD147 on V-ATPase. Firstly, the expression levels of CD147 and V-ATPase were detected in chemotherapy-resistance breast cancer samples. It was demonstrated that V-ATPase was highly expressed in chemotherapy-resistance breast cancer samples, and that its expression was correlated with CD147 expression. Subsequently, MCF-7 and MDA-MB-231 cells were used to study the regulatory effect of CD147 on the expression and function of V-ATPase. Gene transfection or small interfering RNA transfection were used to control the expression of CD147 in the two cell lines. The results revealed that the overexpression of CD147 increased the expression of V-ATPase in MCF-7 cells, whereas CD147 knockdown decreased V-ATPase expression in MDA-MB-231 cells. It was also observed that CD147 affected the V-ATPase activity, regulating the transmembrane pH gradient of cancer cells. These results demonstrated that CD147 was associated with the sensitivity of chemotherapeutic drugs of epirubicin and docetaxel, while pantoprazole was able to partially reverse the CD147-mediated chemoresistance in breast cancer. Therefore, the current study provided a possible mechanism for further examination of drug resistance in breast cancer.

System analysis of the regulation of the immune response by CD147 and FOXC1 in cancer cell lines

CD147, encoded by BSG, is a highly glycosylated transmembrane protein that belongs to the immunological superfamily and expressed on the surface of many types of cancer cells. While CD147 is best known as a potent inducer of extracellular matrix metalloproteinases, it can also function as a key mediator of inflammatory and immune responses. To systematically elucidate the function of CD147 in cancer cells, we performed an analysis of genome-wide profiling across the Cancer Cell Line Encyclopedia (CCLE). We showed that CD147 mRNA expression was much higher than that of most other genes in cancer cell lines. CD147 varied widely across these cell lines, with the highest levels in the ovary (COLO704) and stomach (SNU668), intermediate levels in the lung (RERFLCKJ, NCIH596 and NCIH1651) and lowest levels in hematopoietic and lymphoid tissue (UT7, HEL9217, HEL and MHHCALL3) and the kidney (A704 and SLR20). Genome-wide analyses showed that CD147 expression was significantly negatively correlated with immune-related genes. Our findings implicated CD147 as a novel regulator of immune-related genes and suggest its important role as a master regulator of immune-related responses in cancer cell lines. We also found a high correlation between the expression of CD147 and FOXC1, and proved that CD147 was a direct transcriptional target of FOXC1. Our findings demonstrate that FOXC1 is a novel regulator of CD147 and confirms its role as a master regulator of the immune response.

Deregulated angiogenesis in chronic lung diseases: a possible role for lung mesenchymal progenitor cells (2017 Grover Conference Series)

Chronic lung disease (CLD), including pulmonary fibrosis (PF) and chronic obstructive pulmonary disease (COPD), is the fourth leading cause of mortality worldwide. Both are debilitating pathologies that impede overall tissue function. A common co-morbidity in CLD is vasculopathy, characterized by deregulated angiogenesis, remodeling, and loss of microvessels. This substantially worsens prognosis and limits survival, with most current therapeutic strategies being largely palliative. The relevance of angiogenesis, both capillary and lymph, to the pathophysiology of CLD has not been resolved as conflicting evidence depicts angiogenesis as both reparative or pathologic. Therefore, we must begin to understand and model the underlying pathobiology of pulmonary vascular deregulation, alone and in response to injury induced disease, to define cell interactions necessary to maintain normal function and promote repair. Capillary and lymphangiogenesis are deregulated in both PF and COPD, although the mechanisms by which they co-regulate and underlie early pathogenesis of disease are unknown. The cell-specific mechanisms that regulate lung vascular homeostasis, repair, and remodeling represent a significant gap in knowledge, which presents an opportunity to develop targeted therapies. We have shown that that ABCG2^pos multipotent adult mesenchymal stem or progenitor cells (MPC) influence the function of the capillary microvasculature as well as lymphangiogenesis. A balance of both is required for normal tissue homeostasis and repair. Our current models suggest that when lymph and capillary angiogenesis are out of balance, the non-equivalence appears to support the progression of disease and tissue remodeling. The angiogenic regulatory mechanisms underlying CLD likely impact other interstitial lung diseases, tuberous sclerosis, and lymphangioleiomyomatosis.

Molecular mechanisms of activating c-MET in KSHV+ primary effusion lymphoma

The oncogenic Kaposi's sarcoma–associated herpesvirus (KSHV) is a principal causative agent of primary effusion lymphoma (PEL), which is mostly seen in immunosuppressed patients. PEL is a rapidly progressing malignancy with a median survival time of approximately 6 months even under the conventional chemotherapy. We recently report that the hepatocyte growth factor (HGF)/c-MET pathway is highly activated in PEL cells and represents a promising therapeutic target (Blood. 2015;126(26):2821-31). However, the underlying mechanisms of c-MET activation within PEL cells remain largely unknown. To solve this puzzle, here we have utilized the next generation sequencing (NGS) based bioinformatics approach to investigate the genomic landscape of the c-MET gene and we found that there's no single nucleotide variations (SNVs) occurred in the c-MET genomic regions in a cohort of PEL samples. Consistently, Sanger sequencing analysis of frequently mutated exons such as exon 10, 14 and 19 shows no mutation of these c-MET exons in PEL cell-lines, which further supports the notion that mutations are not the major mechanism responsible for c-MET activation in PEL. Further, we found that a transmembrane receptor protein, Plexin-B1, is expressed in PEL cell-lines, which is required for c-MET-mediated PEL cell survival via direct protein interaction.

Ribonucleotide reductase represents a novel therapeutic target in primary effusion lymphoma

Primary effusion lymphoma (PEL) is a highly aggressive B-cell malignancy that is closely associated with one of oncogenic viruses infection, Kaposi's sarcoma-associated herpesvirus (KSHV). PEL prognosis is poor and patients barely survive more than 6 months even following active chemotherapy interventions. There is therefore an urgent need to discover more effective targets for PEL management. We recently found that the ribonucleotide reductase (RR) subunit M2 is potentially regulated by the key oncogenic HGF/c-MET pathway in PEL (Dai et al., Blood. 2015;126(26):2821-31). In the current study, we set to investigate the role of RR in PEL pathogenesis and to evaluate its potential as a therapeutic target. We report that the RR inhibitor 3-AP actively induces PEL cell cycle arrest through inhibiting the activity of the NF-κB pathway. Using a xenograft model, we found that 3-AP effectively suppresses PEL progression in immunodeficient mice. Transcriptome analysis of 3-AP treated PEL cell lines reveals altered cellular genes, most of whose roles in PEL have not yet been reported. Taken together, we propose that RR and its signaling pathway may serve as novel actionable targets for PEL management.

CD147 and downstream ADAMTSs promote the tumorigenicity of Kaposi's sarcoma-associated herpesvirus infected endothelial cells

Kaposi's sarcoma-associated herpesvirus (KSHV) is the etiologic agent of several human cancers, including Kaposi's sarcoma (KS), which preferentially arise in immunocompromised patients and lack effective therapeutic options. We have previously shown that KSHV or viral protein LANA up-regulates the glycoprotein CD147, thereby inducing primary endothelial cell invasiveness. In the current study, we identify the global network controlled by CD147 in KSHV-infected endothelial cells using Illumina microarray analysis. Among downstream genes, two specific metalloproteases, ADAMTS1 and 9, are strongly expressed in AIDS-KS tissues and contribute to KSHV-infected endothelial cell invasiveness through up-regulation of IL-6 and VEGF. By using a KS-like nude mouse model, we found that targeting CD147 and downstream ADAMTSs significantly suppressed KSHV-induced tumorigenesis in vivo. Taken together, targeting CD147 and associated proteins may represent a promising therapeutic strategy against these KSHV-related malignancies.

EMMPRIN Down-regulating miR-106a/b Modifies Breast Cancer Stem-like Cell Properties via Interaction with Fibroblasts Through STAT3 and HIF-1α

Extracellular matrix metalloproteinase inducer (EMMPRIN) is a heavily glycosylated protein and expresses in cancer cells widely, which plays important roles in tumor progression. However, the role of EMMPRIN in breast cancer stem-like cell properties by interaction with fibroblasts is not known. In the present study, we investigated the effects of fibroblasts on breast cancer stem-like cells. We found that fibroblasts activated by co-cultured breast cancer cells produced higher levels of EMMPRIN, which stimulated the stem-like cell specific, self-renewal and sphere-forming phenotype in breast cancer cells. Increased EMMPRIN expression in activated fibroblasts increased the expression of STAT3 and HIF-1α and showed cancer stem-like cell features in breast cancer cells. We also found that EMMPRIN could down-regulate miR-106a and miR-106b expression in breast cancer cells, which led to activating STAT3 and enhancing HIF-1α expression. Our results illustrated that EMMPRIN has an important role in breast cancer stem-like cells by activation STAT3/HIF-1α through interaction with cancer cells and fibroblasts. The study for the first time indicated that cancer cells and fibroblasts interaction promotes breast cancer cells showing stem-like cells through up-regulation EMMPRIN, and led to inhibiting miR-106a/b expression which targets both STAT3 and HIF-1α expression.

Genomic analysis of xCT-mediated regulatory network: Identification of novel targets against AIDS-associated lymphoma

Kaposi's sarcoma-associated herpesvirus (KSHV) is the etiological agent of primary effusion lymphoma (PEL), a rapidly progressing malignancy mostly arising in HIV-infected patients. Even under conventional chemotherapy, PEL continues to portend nearly 100% mortality within several months, which urgently requires novel therapeutic strategies. We have previously demonstrated that targeting xCT, an amino acid transporter for cystine/glutamate exchange, induces significant PEL cell apoptosis through regulation of multiple host and viral factors. More importantly, one of xCT selective inhibitors, Sulfasalazine (SASP), effectively prevents PEL tumor progression in an immune-deficient xenograft model. In the current study, we use Illumina microarray to explore the profile of genes altered by SASP treatment within 3 KSHV⁺ PEL cell-lines, and discover that many genes involved in oxidative stress/antioxidant defense system, apoptosis/anti-apoptosis/cell death, and cellular response to unfolded proteins/topologically incorrect proteins are potentially regulated by xCT. We further validate 2 downstream candidates, OSGIN1 (oxidative stress-induced growth inhibitor 1) and XRCC5 (X-ray repair cross-complementing protein 5), and evaluate their functional relationship with PEL cell survival/proliferation and chemoresistance, respectively. Together, our data indicate that targeting these novel xCT-regulated downstream genes may represent a promising new therapeutic strategy against PEL and/or other AIDS-related lymphoma.

How, with whom and when: an overview of CD147-mediated regulatory networks influencing matrix metalloproteinase activity

Matrix metalloproteinases (MMPs) comprise a family of 23 zinc-dependent enzymes involved in various pathologic and physiologic processes. In cancer, MMPs contribute to processes from tumour initiation to establishment of distant metastases. Complex signalling and protein transport networks regulate MMP synthesis, cell surface presentation and release. Earlier attempts to disrupt MMP activity in patients have proven to be intolerable and with underwhelming clinical efficacy; thus targeting ancillary proteins that regulate MMP activity may be a useful therapeutic approach. Extracellular matrix metalloproteinase inducer (EMMPRIN) was originally characterized as a factor present on lung cancer cells, which stimulated collagenase (MMP-1) production in fibroblasts. Subsequent studies demonstrated that EMMPRIN was identical with several other protein factors, including basigin (Bsg), all of which are now commonly termed CD147. CD147 modulates the synthesis and activity of soluble and membrane-bound [membrane-type MMPs (MT-MMPs)] in various contexts via homophilic/heterophilic cell interactions, vesicular shedding or cell-autonomous processes. CD147 also participates in inflammation, nutrient and drug transporter activity, microbial pathology and developmental processes. Despite the hundreds of manuscripts demonstrating CD147-mediated MMP regulation, the molecular underpinnings governing this process have not been fully elucidated. The present review summarizes our present knowledge of the complex regulatory systems influencing CD147 biology and provides a framework to understand how CD147 may influence MMP activity.

CD147: regulator of hyaluronan signaling in invasiveness and chemoresistance

Major determinants that influence negative outcome in cancer patients are the abilities of cancer cells to resist current therapies and to invade surrounding host tissue, consequently leading to local and metastatic dissemination. Hyaluronan (HA), a prominent constituent of the tumor microenvironment, not only provides structural support but also interacts with cell surface receptors, especially CD44, that influence cooperative signaling pathways leading to chemoresistance and invasiveness. CD147 (emmprin; basigin) is a member of the Ig superfamily that has also been strongly implicated in chemoresistance and invasiveness. CD147 both regulates HA synthesis and interacts with the HA receptors, CD44, and LYVE-1. Increased CD147 expression induces formation of multiprotein complexes containing CD44 (or LYVE-1) as well as members of the membrane-type matrix metalloproteinase, receptor tyrosine kinase, ABC drug transporter, or monocarboxylate transporter families, which become assembled in specialized lipid raft domains along with CD147 itself. In each case, multivalent HA-receptor interactions are essential for formation or stabilization of the lipid raft complexes and for downstream signaling pathways or transporter activities that are driven by these complexes. We conclude that cooperativity between HA, HA receptors, and CD147 may be a major driver of the interconnected pathways of invasiveness and chemoresistance widely critical to malignancy.

Hyaluronan in the healthy and malignant hematopoietic microenvironment

The fate of both endogenous and transplanted stem cells is dependent on the functional status of the regulatory local microenvironment, which is compromised by disease and therapeutic intervention. The glycosaminoglycan hyaluronan (HA) is a critical component of the hematopoietic microenvironment. We summarize recent advances in our understanding of the role of HA in regulating mesenchymal stem cells, osteoblasts, fibroblasts, macrophages, and endothelium in bone marrow (BM) and their crosstalk within the hematopoietic microenvironment. HA not only determines the volume, hydration, and microfluidics of the BM interstitial space, but also, via interactions with specific receptors, regulates multiple cell functions including differentiation, migration, and production of regulatory factors. The effects of HA are dependent on the polymer size and are influenced by the formation of complexes with other molecules. In healthy BM, HA synthases and hyaluronidases form a molecular network that maintains extracellular HA levels within a discrete physiological window, but HA homeostasis is often perturbed in pathological conditions, including hematological malignancies. Recent studies have suggested that HA synthases may have functions beyond HA production and contribute to the intracellular regulatory machinery. We discuss a possible role for HA synthases, intracellular and extracellular HA in the malignant BM microenvironment, and resistance to therapy.

Induction of hyaluronan production by oncogenic KSHV and the contribution to viral pathogenesis in AIDS patients

Kaposi sarcoma-associated herpesvirus (KSHV) is the etiologic agent for Kaposi's sarcoma (KS) and primary effusion lymphoma (PEL), malignancies arising primarily in immunocompromised patients particularly AIDS-patients, which still lack effective therapy. Hyaluronan (HA) is a large glucuronic acid and has been found closely related to multiple functions in cancer cells, although its role in viral oncogenesis remains largely unknown. Here we provide first evidence that KSHV de novo infection induces HA production from primary endothelial cells through upregulation of HA synthase gene 1 (Has1) and a multifunctional glycoprotein, CD147. Further data demonstrate that KSHV-induced HA production requires viral latent protein, LANA (in particular functional domain A) and MAPK/ERK signaling activities. In functions, HA production is necessary for KSHV/LANA-induced primary endothelial cell invasion, a hallmark feature for KS development. For clinical relevance, our data indicate that the KSHV+ group has higher levels of HA and Has1 activities in its plasma than the KSHV- group of cohort HIV-infected patients. Together, our findings provide innovative insights into the mechanisms of oncogenic virus activation of HA production and its role in virus-associated malignancy pathogenesis, which may help to develop novel therapeutic strategies by targeting HA and related signaling.

xCT, not just an amino-acid transporter: a multi-functional regulator of microbial infection and associated diseases

Expression of xCT, a component of the x_c^– amino-acid transporter, is essential for the uptake of cystine required for intracellular glutathione (GSH) synthesis and maintenance of the intracellular redox balance. Therefore, xCT plays an important role not only in the survival of somatic and immune cells, but also in other aspects of tumorigenesis, including the growth and malignant progression of cancer cells, resistance to anticancer drugs, and protection of normal cells against oxidative damage induced by carcinogens. xCT also functions as a factor required for infection by Kaposi’s sarcoma-associated herpesvirus (KSHV), the causative agent of Kaposi’s sarcoma (KS) and other lymphoproliferative diseases associated with HIV/AIDS. In spite of these advances, our understanding of the role of xCT in the pathogenesis of infectious diseases is still limited. Therefore, this review will summarize recent findings about the functions of xCT in diseases associated with microbial (bacterial or viral) infections, in particular KSHV-associated malignancies. We will also discuss the remaining questions, future directions, as well as evidence that supports the potential benefits of exploring system x_c^– as a target for prevention and clinical management of microbial diseases and cancer.

The biological function and clinical utilization of CD147 in human diseases: a review of the current scientific literature

CD147 or EMMPRIN is a member of the immunoglobulin superfamily in humans. It is widely expressed in human tumors and plays a central role in the progression of many cancers by stimulating the secretion of matrix metalloproteinases (MMPs) and cytokines. CD147 regulates cell proliferation, apoptosis, and tumor cell migration, metastasis and differentiation, especially under hypoxic conditions. CD147 is also important to many organ systems. This review will provide a detailed overview of the discovery, characterization, molecular structure, diverse biological functions and regulatory mechanisms of CD147 in human physiological and pathological processes. In particular, recent studies have demonstrated the potential application of CD147 not only as a phenotypic marker of activated regulatory T cells but also as a potential diagnostic marker for early-stage disease. Moreover, CD147 is recognized as an effective therapeutic target for hepatocellular carcinoma (HCC) and other cancers, and exciting clinical progress has been made in HCC treatment using CD147-directed monoclonal antibodies.

The ability of hyaluronan fragments to reverse the resistance of C6 rat glioma cell line to temozolomide and carmustine

Aim of the study

Hyaluronan (HA) is an extracellular matrix (ECM) polymer that may contribute to the emergence of anti-cancer drug resistance. Attempts to reverse drug resistance using small hyaluronan oligomers (oHA) are being made. The initial reports suggest that the oHA fraction may effectively reverse anti-cancer drug resistance in glioma models. However, the reversal effects of oHA of defined molecular length on glioma cells have not been investigated yet. In this study, we examined HA fragments containing 2 disaccharide units (oHA-2), 5 disaccharide units (oHA-5), and 68 kDa hyaluronan polymer (HA-68k) as agents possibly reversing the resistance of a C6 rat glioma cell line to temozolomide (TMZ) and carmustine (BCNU).

Material and methods

A 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) viability assay was used to assess the cytotoxicity of TMZ and BCNU in the presence or absence of the hyaluronan fragments. By comparing viability of the cells, the reversal effects of HA fragments on TMZ and BCNU resistance in C6 glioma cells were assessed.

Results

We found statistically significant decreases in the viability of cells in the presence of TMZ+oHA-5 as compared to TMZ alone (51.2 ±4.5 vs. 74.2 ±5.8, p = 0.0031), BCNU+o-HA5 as compared to BCNU alone (49.3 ±4.4 vs. 65.6 ±5.7, p = 0.0119), and BCNU+HA-68k as compared to BCNU alone (55.2 ±2.3 vs. 65.6 ±5.7, p = 0.0496).

Conclusions

Conclusions: Hyaluronan oligomers of 5 disaccharide units (oHA-5) significantly reversed the resistance of C6 cells to TMZ and BCNU. The results are only preliminary and a more thorough follow-up investigation is required to assess their actual role.

Sphingosine kinase-2 maintains viral latency and survival for KSHV-infected endothelial cells

Phosphorylation of sphingosine by sphingosine kinases (SphK1 and SphK2) generates sphingosine-1-phosphate (S1P), a bioactive sphingolipid which promotes cancer cell survival and tumor progression in vivo. We have recently reported that targeting SphK2 induces apoptosis for human primary effusion lymphoma (PEL) cell lines infected by the Kaposi’s sarcoma-associated herpesvirus (KSHV), and this occurs in part through inhibition of canonical NF-κB activation. In contrast, pharmacologic inhibition of SphK2 has minimal impact for uninfected B-cell lines or circulating human B cells from healthy donors. Therefore, we designed additional studies employing primary human endothelial cells to explore mechanisms responsible for the selective death observed for KSHV-infected cells during SphK2 targeting. Using RNA interference and a clinically relevant pharmacologic approach, we have found that targeting SphK2 induces apoptosis selectively for KSHV-infected endothelial cells through induction of viral lytic gene expression. Moreover, this effect occurs through repression of KSHV-microRNAs regulating viral latency and signal transduction, including miR-K12-1 which targets IκBα to facilitate activation of NF-κB, and ectopic expression of miR-K12-1 restores NF-κB activation and viability for KSHV-infected endothelial cells during SphK2 inhibition. These data illuminate a novel survival mechanism and potential therapeutic target for KSHV-infected endothelial cells: SphK2-associated maintenance of viral latency.

Prognostic significance of lactate/proton symporters MCT1, MCT4, and their chaperone CD147 expressions in urothelial carcinoma of the bladder

OBJECTIVE

To investigate the prognostic significance of lactate/proton monocarboxylate transporters MCT1, MCT4, and their chaperone CD147 expressions in urothelial carcinoma of the bladder (UCB).

METHODS

We examined the expressions of MCT1, MCT4, and CD147 proteins in a total of 360 cases of UCB by immunohistochemistry. The immunohistochemical expressions were quantified using an ImageJ-based analysis program.

RESULTS

MCT1, MCT4, and CD147 expressions were increased in 130 (36.1%), 168 (46.7%), and 228 (63.3%) UCB cases, respectively. Most tumor cells showed diffuse membranous staining, whereas normal urothelial cells showed negative or weak staining. High levels of MCT1 expression correlated with high World Health Organization grade (P<.001), advanced tumor node metastasis (TNM) stage (P<.001), nonpapillary growth type (P<.001), and lymphatic tumor invasion (P=.010), whereas high levels of MCT4 expression did not significantly correlate with any of these variables. High CD147 expression was associated with high World Health Organization grade (P<.001), advanced tumor node metastatis stage (P<.001), and nonpapillary growth type (P=.003). Univariate analyses revealed that high MCT1 (P<.001) and CD147 (P=.029) expressions were associated with poor overall survival and that high MCT4 expression was correlated with poor recurrence-free survival (P=.036). Multivariate analyses revealed that high MCT1 and MCT4 expressions were independent prognostic factors for poor overall survival and poor recurrence-free survival, respectively, in UCB patients.

CONCLUSION

Our results indicate that increased MCT1, MCT4, and CD147 expressions have prognostic implications in UCB and suggest their roles in urothelial cancer metabolism.

Targeting xCT, a cystine-glutamate transporter induces apoptosis and tumor regression for KSHV/HIV-associated lymphoma

Kaposi’s sarcoma-associated herpesvirus (KSHV) is the etiological agent of primary effusion lymphoma (PEL), which represents a rapidly progressing malignancy arising in HIV-infected patients. Conventional chemotherapy for PEL treatment induces unwanted toxicity and is ineffective — PEL continues to portend nearly 100% mortality within a period of months, which requires novel therapeutic strategies. The amino acid transporter, xCT, is essential for the uptake of cystine required for intracellular glutathione (GSH) synthesis and for maintaining the intracellular redox balance. Inhibition of xCT induces growth arrest in a variety of cancer cells, although its role in virus-associated malignancies including PEL remains unclear. In the current study, we identify that xCT is expressed on the surface of patient-derived KSHV⁺ PEL cells, and targeting xCT induces caspase-dependent cell apoptosis. Further experiments demonstrate the underlying mechanisms including host and viral factors: reducing intracellular GSH while increasing reactive oxygen species (ROS), repressing cell-proliferation-related signaling, and inducing viral lytic genes. Using an immune-deficient xenograft model, we demonstrate that an xCT selective inhibitor, Sulfasalazine (SASP), prevents PEL tumor progression in vivo. Together, our data provide innovative and mechanistic insights into the role of xCT in PEL pathogenesis, and the framework for xCT-focused therapies for AIDS-related lymphoma in future.

EMMPRIN co-expressed with matrix metalloproteinases predicts poor prognosis in patients with osteosarcoma

Several studies have focused on the relationships between the expression of extracellular matrix metalloproteinase inducer (EMMPRIN) and the prognosis of patients with malignant tumors. However, few of these have investigated the expression of EMMPRIN in osteosarcoma. We examined expression levels of EMMPRIN immunohistochemically in 53 cases of high-grade osteosarcoma of the extremities and analyzed the correlation of its expression with patient prognosis. The correlation between matrix metalloproteinases (MMPs) and EMMPRIN expression and the prognostic value of co-expression were also analyzed. Staining positivity for EMMPRIN was negative in 7 cases, low in 17, moderate in 19, and strong in 10. The overall and disease-free survivals (OS and DFS) in patients with higher EMMPRIN expression (strong-moderate) were significantly lower than those in the lower (weak-negative) group (0.037 and 0.024, respectively). In multivariate analysis, age (P=0.004), location (P=0.046), and EMMPRIN expression (P=0.038) were significant prognostic factors for overall survival. EMMPRIN expression (P=0.024) was also a significant prognostic factor for disease-free survival. Co-expression analyses of EMMPRIN and MMPs revealed that strong co-expression of EMMPRIN and membrane-type 1 (MT1)-MMP had a poor prognostic value (P=0.056 for DFS, P=0.006 for OS). EMMPRIN expression and co-expression with MMPs well predict the prognosis of patients with extremity osteosarcoma, making EMMPRIN a possible therapeutic target in these patients.

SELDI-TOF analysis of glioblastoma cyst fluid is an approach for assessing cellular protein expression

OBJECTIVES

In about 10% of glioblastoma patients, preoperative MRI discloses the presence of tumor cysts. Whereas the impact of cystic appearance on prognosis has been discussed extensively, only little is known about the tumor cyst fluid. In this study, we tested the feasibility of the surface enhanced laser desorption ionization time of flight (SELDI-TOF) technique to detect cyst fluid proteins.

METHODS

Cyst fluid was collected from 21 glioblastoma patients for SELDI-TOF analysis and compared to control cerebrospinal fluids from 15 patients with spinal stenosis. Resulting protein peaks with significant differences between groups were further described, using the molecular weight in an internet search of protein databases and publications. Two potential cyst fluid proteins, basigin and ferritin light chain, were selected for immunohistological detection in the histologic slides of the patients, metallothionein (MT) served as negative control.

RESULTS

As supposed from the results of the SELDI-TOF analysis, basigin and ferritin were detected immunohistochemically in the cyst wall, whereas MT was more equally distributed between the cyst wall and the surrounding tumor tissue. Median survival time of the patients was 20 months (range 2 to 102 months) and correlated with age, but not with expression of the three proteins.

DISCUSSION

The SELDI-TOF approach reveals a number of proteins, potentially present in glioblastoma cyst fluid. Identification of these proteins in tumor cells may help understand the pathogenetic pathways and the prognostic value of cystic changes.

Targeting sphingosine kinase induces apoptosis and tumor regression for KSHV-associated primary effusion lymphoma

Sphingosine kinase (SPHK) is overexpressed by a variety of cancers, and its phosphorylation of sphingosine results in accumulation of sphingosine-1-phosphate (S1P) and activation of antiapoptotic signal transduction. Existing data indicate a role for S1P in viral pathogenesis, but roles for SPHK and S1P in virus-associated cancer progression have not been defined. Rare pathologic variants of diffuse large B-cell lymphoma arise preferentially in the setting of HIV infection, including primary effusion lymphoma (PEL), a highly mortal tumor etiologically linked to the Kaposi's sarcoma-associated herpesvirus (KSHV). We have found that ABC294640, a novel clinical-grade small molecule selectively targeting SPHK (SPHK2 >> SPHK1), induces dose-dependent caspase cleavage and apoptosis for KSHV(+) patient-derived PEL cells, in part through inhibition of constitutive signal transduction associated with PEL cell proliferation and survival. These results were validated with induction of PEL cell apoptosis using SPHK2-specific siRNA, as well as confirmation of drug-induced SPHK inhibition in PEL cells with dose-dependent accumulation of proapoptotic ceramides and reduction of intracellular S1P. Furthermore, we demonstrate that systemic administration of ABC294640 induces tumor regression in an established human PEL xenograft model. Complimentary ex vivo analyses revealed suppression of signal transduction and increased KSHV lytic gene expression within drug-treated tumors, with the latter validated in vitro through demonstration of dose-dependent viral lytic gene expression within PEL cells exposed to ABC294640. Collectively, these results implicate interrelated mechanisms and SPHK2 inhibition in the induction of PEL cell death by ABC294640 and rationalize evaluation of ABC294640 in clinical trials for the treatment of KSHV-associated lymphoma.

Chemotherapy-induced hyaluronan production: a novel chemoresistance mechanism in ovarian cancer

Background

Hyaluronan (HA) an important component of the extracellular matrix, has been linked to tumor progression and drug resistance in several malignancies. However, limited data is available for ovarian cancer. This study investigated the role of hyaluronan (HA) and a potential link between the HA-CD44 pathway and membrane ATP binding cassette (ABC) transporter proteins in ovarian cancer chemoresistance.

Methods

We investigated the ability of HA to block the cytotoxic effects of the chemotherapy drug carboplatin, and to regulate the expression of ABC transporters in ovarian cancer cells. We also examined HA serum levels in ovarian cancer patients prior to and following chemotherapy and assessed its prognostic relevance.

Results

HA increased the survival of carboplatin treated ovarian cancer cells expressing the HA receptor, CD44 (OVCAR-5 and OV-90). Carboplatin significantly increased expression of HAS2, HAS3 and ABCC2 and HA secretion in ovarian cancer cell conditioned media. Serum HA levels were significantly increased in patients following platinum based chemotherapy and at both 1st and 2nd recurrence when compared with HA levels prior to treatment. High serum HA levels (>50 μg/ml) prior to chemotherapy treatment were associated with significantly reduced progression-free (P = 0.014) and overall survival (P = 0.036). HA production in ovarian cancer cells was increased in cancer tissues collected following chemotherapy treatment and at recurrence. Furthermore HA treatment significantly increased the expression of ABC drug transporters (ABCB3, ABCC1, ABCC2, and ABCC3), but only in ovarian cancer cells expressing CD44. The effects of HA and carboplatin on ABC transporter expression in ovarian cancer cells could be abrogated by HA oligomer treatment. Importantly, HA oligomers increased the sensitivity of chemoresistant SKOV3 cells to carboplatin.

Conclusions

Our findings indicate that carboplatin chemotherapy induces HA production which can contribute to chemoresistance by regulating ABC transporter expression. The HA-CD44 signaling pathway is therefore a promising target in platinum resistant ovarian cancer.

Lymphatic vessel endothelial hyaluronan receptor-1 is a novel prognostic indicator for human hepatocellular carcinoma

Angiogenesis is an important mechanism of tumor development, growth and metastasis in hepatocellular carcinoma (HCC). The poor prognosis of HCC patients has been associated with a failure to detect recurrences following surgery. In the present study, we investigated the association between the patient characteristics and the expression of angiogenic genes to identify early biomarkers of HCC. A comprehensive angiogenic gene expression profile was obtained by paired TaqMan gene array analysis of primary HCC nodules and adjacent non-HCC liver tissue from 12 patients. A total of 14 genes were found to be differentially expressed in HCC liver nodules (>2-fold change); the genes encoding collagen type XVα1, IVα1 and IVα2 were upregulated and the genes associated with vessel growth, neuropilin 2 (NRP2) and lymphatic vessel endothelial hyaluronan receptor-1 (LYVE-1) were downregulated. The histopathological analysis revealed that the evolution of HCC nodules from well to poorly differentiated was associated with a 5-fold decrease in LYVE-1 expression, reaching its lowest level early during the transition. The significance of this gene as a biomarker of postoperative survival was demonstrated by a 2-fold decrease in overall survival (OS) rates in the low expression group compared to the high expression group. The multivariate and univariate Cox regression analyses identified LYVE-1 expression as a significant independent prognostic parameter of OS [hazard ratio (HR)=3.067; 95% confidence interval (CI): 1.507-6.273; P=0.0021]. Thus, the results of this study suggested that LYVE-1 expression may constitute a novel early biomarker of postoperative survival in HCC patients.

CD147, CD44, and the epidermal growth factor receptor (EGFR) signaling pathway cooperate to regulate breast epithelial cell invasiveness

The immunoglobulin superfamily glycoprotein CD147 (emmprin; basigin) is associated with an invasive phenotype in various types of cancers, including malignant breast cancer. We showed recently that up-regulation of CD147 in non-transformed, non-invasive breast epithelial cells is sufficient to induce an invasive phenotype characterized by membrane type-1 matrix metalloproteinase (MT1-MMP)-dependent invadopodia activity (Grass, G. D., Bratoeva, M., and Toole, B. P. (2012) Regulation of invadopodia formation and activity by CD147. J. Cell Sci. 125, 777-788). Here we found that CD147 induces breast epithelial cell invasiveness by promoting epidermal growth factor receptor (EGFR)-Ras-ERK signaling in a manner dependent on hyaluronan-CD44 interaction. Furthermore, CD147 promotes assembly of signaling complexes containing CD147, CD44, and EGFR in lipid raftlike domains. We also found that oncogenic Ras regulates CD147 expression, hyaluronan synthesis, and formation of CD147-CD44-EGFR complexes, thus forming a positive feedback loop that may amplify invasiveness. Last, we showed that malignant breast cancer cells are heterogeneous in their expression of surface-associated CD147 and that high levels of membrane CD147 correlate with cell surface EGFR and CD44 levels, activated EGFR and ERK1, and activated invadopodia. Future studies should evaluate CD147 as a potential therapeutic target and disease stratification marker in breast cancer.

Emmprin and KSHV: new partners in viral cancer pathogenesis

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Emmprin regulates pathogenic elements relevant to virus-associated cancer, including drug resistance and cell migration.

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Kaposi's sarcoma-associated herpesvirus (KSHV) regulates emmprin expression and downstream function.

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Targeting emmprin or its interacting proteins at the cell surface suppresses KSHV-induced pathogenesis in vitro.

Emmprin (CD147; basigin) is a multifunctional glycoprotein expressed at higher levels by cancer cells and stromal cells in the tumor microenvironment. Through direct effects within tumor cells and promotion of tumor–stroma interactions, emmprin participates in induction of tumor cell invasiveness, angiogenesis, metastasis and chemoresistance. Although its contribution to cancer progression has been widely studied, the role of emmprin in viral oncogenesis still remains largely unclear, and only a small body of available literature implicates emmprin-associated mechanisms in viral pathogenesis and tumorigenesis. We summarize these data in this review, focusing on the role of emmprin in pathogenesis associated with the Kaposi sarcoma-associated herpesvirus (KSHV), a common etiology for cancers arising in the setting of immune suppression. We also discuss future directions for mechanistic studies exploring roles for emmprin in viral cancer pathogenesis.

CD147 mediates chemoresistance in breast cancer via ABCG2 by affecting its cellular localization and dimerization

CD147 and ABCG2 both have been reported to mediate Multidrug resistance (MDR) in breast cancer. Recent study demonstrates that CD147 could form a complex with ABCG2 on the cell membrane in primary effusion lymphoma. However, whether these two molecules regulate each other in breast cancer and result in MDR is not clear. We established four MCF-7 cell lines transfected with CD147 and/or ABCG2 and found that CD147 could increase the expression and dimerization of ABCG2, affect its cellular localization and regulate its drug transporter function. The findings derived from cells were confirmed subsequently in clinic samples of chemotherapy-sensitive/resistant breast cancer.

Dangerous liaisons: molecular basis for a syndemic relationship between Kaposi's sarcoma and P. falciparum malaria

The most severe manifestations of malaria (caused by Plasmodium falciparum) occur as a direct result of parasitemia following invasion of erythrocytes by post-liver blood-stage merozoites, and during subsequent cyto-adherence of infected erythrocytes to the vascular endothelium. However, the disproportionate epidemiologic clustering of severe malaria with aggressive forms of endemic diseases such as Kaposi's sarcoma (KS), a neoplasm that is etiologically linked to infection with KS-associated herpesvirus (KSHV), underscores the significance of previously unexplored co-pathogenetic interactions that have the potential to modify the overall disease burden in co-infected individuals. Based on recent studies of the mechanisms that P. falciparum and KSHV have evolved to interact with their mutual human host, several new perspectives are emerging that highlight a surprising convergence of biological themes potentially underlying their associated co-morbidities. Against this background, ongoing studies are rapidly constructing a fascinating new paradigm in which the major host receptors that control parasite invasion (Basigin/CD147) and cyto-adherence (CD36) are, surprisingly, also important targets for exploitation by KSHV. In this article, we consider the major pathobiological implications of the co-option of Basigin/CD147 and CD36 signaling pathways by both P. falciparum and KSHV, not only as essential host factors for parasite persistence but also as important mediators of the pro-angiogenic phenotype within the virus-infected endothelial microenvironment. Consequently, the triangulation of interactions between P. falciparum, KSHV, and their mutual human host articulates a syndemic relationship that points to a conceptual framework for prevalence of aggressive forms of KS in malaria-endemic areas, with implications for the possibility of dual-use therapies against these debilitating infections in resource-limited parts of the world.

CD147 promotes MTX resistance by immune cells through up-regulating ABCG2 expression and function

BACKGROUND

Methotrexate (MTX) is a drug used to treat psoriasis due to inducing immune cell apoptosis. However, certain patients show MTX resistant. CD147, highly expressed by psoriatic PBMCs, is assumed to regulate MTX sensitivity. The underlining mechanism is still relatively understudied.

OBJECTIVE

To understand the mechanisms of that CD147 promotes MTX resistance in immune cells.

METHODS

The expression of CD147 and ABCG2 in PBMCs from psoriatic patients, cellular apoptosis and intracellular MTX amount were measured. We also checked the cellular drug sensitivity of CHO (Chinese Hamster Ovary) cell lines with introduced CD147 and Jurkat T cells depeleted CD147. By immunoprecipitation, we detected the interaction between CD147 and ABCG2.

RESULTS

Both ABCG2 and CD147 are highly expressed in psoriatic PBMCs. Cultured in vitro, the PBMCs from psoriatic patients were more resistant to MTX-induced apoptosis comparing to PBMCs from healthy people. Further studies demonstrated that exogenous overexpression of CD147 in CHO cells increased ABCG2 protein level. After MTX treatment, CD147 overexpressing CHO cells showed lower apoptosis rate and lower intracellular MTX concentration. On the contrary, knockdown of CD147 by shRNA in Jurkat T cells decreased ABCG2 expression, as well as increased MTX-induced apoptosis and decreased MTX efflux. Immunoprecipitation experiment revealed that the trans-membrane domain of CD147 conferred its' interaction with ABCG2.

CONCLUSION

Our study suggests a role of CD147 in regulating ABCG2 transportation of MTX in immune cells. Strategies involving targeting CD147 could be considered in clinical treatment of psoriatic patients resistant to MTX.

CD147-dependent heterogeneity in malignant and chemoresistant properties of cancer cells

CD147 (alias emmprin or basigin), an integral plasma membrane glycoprotein and a member of the Ig superfamily, is widespread in normal tissues, but highly up-regulated in many types of malignant cancer cells. CD147 is multifunctional, with numerous binding partners. Recent studies suggest that complexes of CD147 with the hyaluronan receptor CD44 and associated transporters and receptor tyrosine kinases are enriched in the plasma membrane of cancer stem-like cells. Here, we show that subpopulations of tumor cell lines constitutively expressing high levels of cell-surface CD147 exhibit cancer stem-like cell properties; that is, they exhibit much greater invasiveness, anchorage-independent growth, spheroid formation, and drug resistance in vitro and higher tumorigenicity in vivo than those constitutively expressing low levels of cell-surface CD147. Primary CD147-rich cell subpopulations derived from mouse mammary adenocarcinomas also exhibit high levels of invasiveness and spheroid-forming capacity, whereas CD147-low cells do not. Moreover, localization at the plasma membrane of CD44, the EGF receptor, the ABCB1 and ABCG2 drug transporters, and the MCT4 monocarboxylate transporter is elevated in cells constitutively expressing high levels of cell-surface CD147. These results show that CD147 is associated with assembly of numerous pro-oncogenic proteins in the plasma membrane and may play a fundamental role in properties characteristic of cancer stem-like cells.

Kaposi's sarcoma herpesvirus lytic replication compromises apoptotic response to p53 reactivation in virus-induced lymphomas

Primary effusion lymphomas (PELs) are aggressive Kaposi's sarcoma herpesvirus (KSHV)-induced malignancies with median survival time <6 months post-diagnosis. Mutations in the TP53 gene seldom occur in PELs, suggesting that genetic alterations in the TP53 are not selected during PEL progression. We have reported that p53 reactivation by an inhibitor of the p53-MDM2 interaction, Nutlin-3, induces selective and massive apoptosis in PEL cells leading to efficient anti-tumor activity in a subcutaneous xenograft model for PEL. Here, we show compelling anti-tumor activity of Nutlin-3 in the majority of intraperitoneal PEL xenografts in vivo. Interestingly, our results demonstrate that spontaneous induction of viral lytic replication in tumors could drastically attenuate the p53-dependent apoptotic response to Nutlin-3. Moreover, viral reactivation compromised p53-dependent apoptosis in PEL cells treated with genotoxic anti-cancer agents doxorubicin and etoposide. We have recently demonstrated that the Ser/Thr kinases Pim 1 and 3 are required to trigger induction of the lytic replication cascade of KSHV. We have now assessed the ability of a novel Pim kinase inhibitor to restore the Nutlin-3-induced cytotoxicity in lytic PEL cells. PEL cells induced to lytic replication by phorbol esters showed 50% inhibition of active viral replication following treatment with the Pim kinase inhibitor. Importantly, co-treatment of these cells with the kinase inhibitor and Nutlin-3 resulted in a robust restoration of the Nutlin-3-induced cell death. These results highlight the potential impact of activation of viral lytic replication on disease progression and response to treatment in KSHV-induced lymphomas.

KSHV-Encoded MicroRNAs: Lessons for Viral Cancer Pathogenesis and Emerging Concepts

The human genome contains microRNAs (miRNAs), small noncoding RNAs that orchestrate a number of physiologic processes through regulation of gene expression. Burgeoning evidence suggests that dysregulation of miRNAs may promote disease progression and cancer pathogenesis. Virus-encoded miRNAs, exhibiting unique molecular signatures and functions, have been increasingly recognized as contributors to viral cancer pathogenesis. A large segment of the existing knowledge in this area has been generated through characterization of miRNAs encoded by the human gamma-herpesviruses, including the Kaposi's sarcoma-associated herpesvirus (KSHV). Recent studies focusing on KSHV miRNAs have led to a better understanding of viral miRNA expression in human tumors, the identification of novel pathologic check points regulated by viral miRNAs, and new insights for viral miRNA interactions with cellular ("human") miRNAs. Elucidating the functional effects of inhibiting KSHV miRNAs has also provided a foundation for further translational efforts and consideration of clinical applications. This paper summarizes recent literature outlining mechanisms for KSHV miRNA regulation of cellular function and cancer-associated pathogenesis, as well as implications for interactions between KSHV and human miRNAs that may facilitate cancer progression. Finally, insights are offered for the clinical feasibility of targeting miRNAs as a therapeutic approach for viral cancers.