CD147 promotes Src-dependent activation of Rac1 signaling through STAT3/DOCK8 during the motility of hepatocellular carcinoma cells

RHO GTPase family in hepatocellular carcinoma

RHO GTPases are a subfamily of the RAS superfamily of proteins, which are highly conserved in eukaryotic species and have important biological functions, including actin cytoskeleton reorganization, cell proliferation, cell polarity, and vesicular transport. Recent studies indicate that RHO GTPases participate in the proliferation, migration, invasion and metastasis of cancer, playing an essential role in the tumorigenesis and progression of hepatocellular carcinoma (HCC). This review first introduces the classification, structure, regulators and functions of RHO GTPases, then dissects its role in HCC, especially in migration and metastasis. Finally, we summarize inhibitors targeting RHO GTPases and highlight the issues that should be addressed to improve the potency of these inhibitors.

Deciphering the role of DOCK8 in tumorigenesis by regulating immunity and the application of nanotechnology in DOCK8 deficiency therapy

The dedicator of cytokinesis 8 (DOCK8) immunodeficiency syndrome is a severe immune disorder and characterized by serum IgE levels elevation, fungal and viral infections, dermatitis and food allergies. It was well known that DOCK8 is crucial for the survival and function of multiple immune related cells. However, the critical role of DOCK8 on tumorigenesis through regulating immunity is poorly investigated. Accumulating evidences indicated that DOCK8 could affect tumorigenesis by regulating the immunity through immune cells, including NK cells, T cells, B cells and dendritic cells. Here, we summarized and discussed the critical role of DOCK8 in cytoskeleton reconstruction, CD4+ T cell differentiation, immune synaptic formation, tumor immune infiltration, tumor immune surveillance and tumorigenesis. Furthermore, the potential roles of nanotechnology in improving the hematopoietic stem cell transplantation-based therapy for DOCK8 deficiency diseases are also highlighted and discussed.

ERα inhibits mesenchymal and amoeboidal movement of liver cancer cell via Gα12

Hepatocellular carcinoma (HCC) is the second most common cancer worldwide, demonstrating aggressiveness and mortality more frequently in men than in women. Despite reports regarding the inhibitory ability of estrogen receptor alpha (ERα, ESR1) in certain cancer progression, targets and the basis of underlying gender disparity in HCC worsening remain elusive. Here, we report the ability of ERα to transcriptionally inhibit G protein subunit alpha 12 (Gα12) responsible for HCC worsening. First, using human samples and public database, the expression of ERα and Gα12 in HCC was examined. Then, quantitative real-time PCR, chromatin immunoprecipitation-assay, luciferase assay, and immunoblottings of liver cancer cell lines confirmed the inhibitory ability of ERα on Gα12 and HCC progression. Gα12 promoted mesenchymal characteristics and amoeboidal movement, which was antagonized by ERα overexpression. Additionally, we found microRNA-141 and -200a as downstream targets of the Gα12 signaling axis for cancer malignancy regulation under the control of ERα. As for in-depth mechanism, PTP4A1 was found to be directly inhibited by microRNA-141 and -200a. Moreover, we found the inhibitory effect of ERα on amoeboidal movement by analyzing the morphology and blebbing of liver cancer cells and the active form of MLC levels. The identified targets and ESR1 levels are inversely correlated in human specimens, as well as with sex-biased survival rates of HCC patients. Collectively, ERα-dependent repression of Gα12 and consequent changes in the Gα12 signaling may explain the gender disparity in HCC, providing pharmacological clues for the control of metastatic HCC. This article is protected by copyright. All rights reserved.

NETME: on-the-fly knowledge network construction from biomedical literature

BACKGROUND

The rapidly increasing biological literature is a key resource to automatically extract and gain knowledge concerning biological elements and their relations. Knowledge Networks are helpful tools in the context of biological knowledge discovery and modeling.

RESULTS

We introduce a novel system called NETME, which, starting from a set of full-texts obtained from PubMed, through an easy-to-use web interface, interactively extracts biological elements from ontological databases and then synthesizes a network inferring relations among such elements. The results clearly show that our tool is capable of inferring comprehensive and reliable biological networks.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s41109-021-00435-x.

Can CD147 work as a therapeutic target for tumors through COVID-19 infection?

In this review, we discussed an interesting case infected with "COVID-19" (Corona Virus Disease 2019). The patients with Hodgkin's lymphoma recovered after infection with COVID-19. It may be that COVID-19 activates the patient's immune system, or it may be a coincidence. COVID-19 spike protein can interact with CD147 and use it as an entry to invade host cells. CD147 is a partner of SLC3A2, which is the chaperone subunit of cystine/glutamate reverse transporter (system XC). The catalytic subunit of system XC is SLC7A11. SLC7A11 mediated cysteine uptake plays a key role in ferroptosis. Through literature review and data analysis, we suggest that CD147, as a new potential COVID-19 infection entry, may also lead to ferroptosis of host cells. Our hypothesis is that spike protein of COVID-19 induced ferroptosis in host cells via CD147/SLC3A2/SLC7A11 complex. This is another explanation for the cancer patient recovered after COVID-19 infection.

Activation of STAT transcription factors by the Rho-family GTPases

The Rho-family of small GTPases are biological molecular switches that are best known for their regulation of the actin cytoskeleton. Through their activation and stimulation of downstream effectors, the Rho-family control pathways involved in cellular morphology, which are commonly activated in cancer cell invasion and metastasis. While this makes them excellent potential therapeutic targets, a deeper understanding of the downstream signalling pathways they influence will be required for successful drug targeting. Signal transducers and activators of transcription (STATs) are a family of transcription factors that are hyper-activated in most cancer types and while STATs are widely understood to be activated by the JAK family of kinases, many additional activators have been discovered. A growing number of examples of Rho-family driven STAT activation, largely of the oncogenic family members, STAT3 and STAT5, are being identified. Cdc42, Rac1, RhoA, RhoC and RhoH have all been implicated in STAT activation, contributing to Rho GTPase-driven changes in cellular morphology that lead to cell proliferation, invasion and metastasis. This highlights the importance and therapeutic potential of the Rho-family as regulators of non-canonical activation of STAT signalling.

Small Rho GTPases and their associated RhoGEFs mutations promote immunological defects in primary immunodeficiencies

Primary immunodeficiencies (PIDs) are associated with deleterious mutations of genes that encode proteins involved in actin cytoskeleton reorganisation. This deficiency affects haematopoietic cells. PID results in the defective function of immune cells, such as impaired chemokine-induced motility, receptor signalling, development and maturation. Some of the genes mutated in PIDs are related to small Ras homologous (Rho) guanosine triphosphatase (GTPase), one of the families of the Ras superfamily. Most of these genes act as molecular switches by cycling between active guanosine triphosphate-bound and inactive guanosine diphosphate-bound forms to control multiple cellular functions. They are best studied for their role in promoting cytoskeleton reorganisation, cell adhesion and motility. Currently, only three small Rho GTPases, namely, Rac2, Cdc42 and RhoH, have been identified in PIDs. However, several other Rho small G proteins might also contribute to the deregulation and phenotype observed in PIDs. Their contribution in PIDs may involve their main regulator, Rho guanine nucleotide exchange factors such as DOCK2 and DOCK8, wherein mutations may result in the impairment of small Rho GTPase activation. Thus, this review outlines the potential contribution of several small Rho GTPases to the promotion of PIDs.

Downregulation of caveolin-1 promotes murine breast cancer cell line progression by highly glycosylated CD147

Caveolin-1 (CAV-1) can extensively regulate lipid transportation, cell growth and cell death. In the present study, we revealed a novel function of CAV-1 in inhibiting glycosylation of other molecules in murine breast cancer cell line. After the silencing of CAV-1, we found that the mRNA and protein expressions of cluster of differentiation 147 (CD147) and its related molecules (MCT4, matrix metalloproteinase MMP2 and MMP9) increased in the breast cancer cells. Meanwhile, the migration and invasion of the breast cancer cells were significantly enhanced assessed by cell wound healing experiment and transwell assays. Further, the gelatin zymography and lactate assay in the cells also showed the strengthened enzyme activity of MMP9 and the increased extracellular lactate concentration, respectively, after the silencing of CAV-1. Notably, the glycosylation level of CD147 overtly increased after the inhibition of CAV-1 detected by Western Blot analysis, whereas upregulation of CAV-1 did the opposite. Therefore, the findings suggest that the downregulation of CAV-1 can promote breast cancer cell progression probably by highly glycosylated CD147.

Hemolysis inhibits humoral B-cell responses and modulates alloimmunization risk in patients with sickle cell disease

Red blood cell alloimmunization remains a barrier for safe and effective transfusions in sickle cell disease (SCD), but the associated risk factors remain largely unknown. Intravascular hemolysis, a hallmark of SCD, results in the release of heme with potent immunomodulatory activity, although its effect on SCD humoral response, specifically alloimmunization, remains unclear. Here, we found that cell-free heme suppresses human B-cell plasmablast and plasma cell differentiation by inhibiting the DOCK8/STAT3 signaling pathway, which is critical for B-cell activation, as well as by upregulating heme oxygenase 1 (HO-1) through its enzymatic byproducts, carbon monoxide and biliverdin. Whereas nonalloimmunized SCD B cells were inhibited by exogenous heme, B cells from the alloimmunized group were nonresponsive to heme inhibition and readily differentiated into plasma cells. Consistent with a differential B-cell response to hemolysis, we found elevated B-cell basal levels of DOCK8 and higher HO-1-mediated inhibition of activated B cells in nonalloimmunized compared with alloimmunized SCD patients. To overcome the alloimmunized B-cell heme insensitivity, we screened several heme-binding molecules and identified quinine as a potent inhibitor of B-cell activity, reversing the resistance to heme suppression in alloimmunized patients. B-cell inhibition by quinine occurred only in the presence of heme and through HO-1 induction. Altogether, these data suggest that hemolysis can dampen the humoral B-cell response and that B-cell heme responsiveness maybe a determinant of alloimmunization risk in SCD. By restoring B-cell heme sensitivity, quinine may have therapeutic potential to prevent and inhibit alloimmunization in SCD patients.

Tumor microenvironment and Oral Squamous Cell Carcinoma: A crosstalk between the inflammatory state and tumor cell migration

OBJECTIVES

To analyze the inflammatory millieu in oral squamous cell carcinoma (OSCC) tumors and the influence of macrophages related-cytokines on the tumor cell migration.

MATERIALS AND METHODS

Inflammatory protein profile and macrophage population (M2/M1 ratio) of human OSCC fragments were analyzed by proteomic analysis and flow cytometry assay respectively. To evaluate the effects of inflammation on OSCC behavior, we analyzed the role of polarized macrophages and cytokines (IL-6, IL-1β and TNF-α) on OSCC cell lines (SCC25 and Cal27) responsiveness by western blotting (cell signaling) and time-lapse (cell migration). Also, it was addressed the crosstalk of IL-6-STAT3 axis with cell migration signaling using a STAT3 inhibitor (Stattic®) and a pull down assay for the RhoGTPase Rac1 activity.

RESULTS

It was observed a ~2 fold predominance of M2 over M1 macrophages and a pro-inflammatory state in OSCC fragments. The M2 conditioned media increased migration speed and directionality of highly invasive OSCC cells (SCC25). OSCC cell lines were responsive to cytokine stimuli (IL6, IL-1β and TNF-α), but only IL-6 increased migration properties of OSCC cells. This effect was dependent on STAT3-phosphorylation levels, which interfered with Rac1 activation levels.

CONCLUSION

Our results suggest that the inflammatory milieu might favor invasion and metastasis of OSCC by the direct effect of macrophage-related cytokines on tumor migration.

CD147 promotes collective invasion through cathepsin B in hepatocellular carcinoma

Background

Mounting evidence suggests that solid tumors display the features of collective invasion, however, the molecular mechanisms are far from clear. This study aims to verify the role and the underlying mechanisms of CD147 in collective invasion in hepatocellular carcinoma.

Methods

Immunostaining was used to analyze human hepatocellular carcinoma specimens and three-dimensional cultures. Three-dimensional invasion model was established to mimic in vivo invasion. RNA-sequencing was used to identify downstream effectors.

Results

Human hepatocellular carcinoma underwent collective invasion and CD147 was observed to be upregulated at the invasive front of tumor cell groups. CD147 was demonstrated to promote collective invasion using the modified three-dimensional invasion model, which recapitulated the main features of collective invasion. Through transcriptome analysis and enzyme activity assay, we found that CD147 enhanced cathepsin B expression and activity. Upregulated cathepsin B in hepatocellular carcinoma cells facilitated migration and invasion, which mediated CD147-induced invasive phenotype in hepatocellular carcinoma. In terms of mechanism, we found that CD147 promoted cathepsin B transcription by activating β-catenin signaling as a result of reduced GSK-3β expression. Furthermore, we found that elevated expression of CD147 as well as cathepsin B were correlated with poor prognosis in patients with hepatocellular carcinoma.

Conclusions

CD147 promotes hepatocellular carcinoma cells collective invasion via upregulating cathepsin B expression and targeting CD147 would be valuable for the development of novel therapeutic modalities against invasion and metastasis of cancer.

Cancer-Associated Fibroblasts Promote Angiogenesis of Hepatocellular Carcinoma by VEGF-Mediated EZH2/VASH1 Pathway

Background:

Hepatocellular carcinoma is a highly vascularized tumor, so it is critical to study its angiogenesis. Cancer-associated fibroblasts and enhancer of zeste homolog 2 play an important role in tumor angiogenesis and became significant hallmarks of cancer. But the relationship between enhancer of zeste homolog-2 and cancer-associated fibroblasts in response to angiogenesis and its precise mechanism remains unclear.

Methods:

The separation of cancer-associated fibroblasts was identified by immunofluorescence. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide analysis was used to reveal the proliferation of human umbilical vein endothelial cells. Vascular endothelial growth factor level was quantified by enzyme-linked immunosorbent assay. The wound healing, transwell, and vascular tube formation assays were used to identify the capability of migration, invasion, and tube formation of human umbilical vein endothelial cells in vitro. The detection of tumor angiogenesis was also performed in vivo. Finally, the level of enhancer of zeste homolog-2 and vasohibin 1 were determined by quantitative real-time polymerase chain reaction and Western blotting.

Results:

In comparison to control and condition medium noncancerous fibroblasts groups, the condition medium cancer-associated fibroblasts could significantly promote the proliferation, migration, invasion, and angiogenesis of human umbilical vein endothelial cells. We found that cancer-associated fibroblasts promoted angiogenesis of human umbilical vein endothelial cells via vascular endothelial growth factor secretion in vitro and in vivo. The upregulation of enhancer of zeste homolog 2 by vascular endothelial growth factor inhibited the expression of vasohibin 1, thus promoting the proliferation and angiogenesis of human umbilical vein endothelial cells. Taken together, the cancer-associated fibroblasts of hepatocellular carcinoma regulate the enhancer of zeste homolog-2/vasohibin 1 pathway via vascular endothelial growth factor secretion, thereby promoting the proliferation and angiogenesis of human umbilical vein endothelial cells.

Conclusion:

Our study identified the relationship between cancer-associated fibroblasts and enhancer of zeste homolog-2 and confirmed the pivotal role of cancer-associated fibroblasts in angiogenesis of hepatocellular carcinoma. Cancer-associated fibroblasts promote angiogenesis of hepatocellular carcinoma by vascular endothelial growth factor–mediated enhancer of zeste homolog-2/vasohibin 1 pathway and may be a potentially useful therapeutic target for hepatocellular carcinoma.

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.

Pseudolaric acid B exhibits anti-cancer activity on human hepatocellular carcinoma through inhibition of multiple carcinogenic signaling pathways

BACKGROUND

Pseudolaric acid B (PAB), a diterpene acid isolated from the root bark of Pseudolarix kaempferi, exhibits a potent anti-cancer activity in a variety of tumor cells.

PURPOSE

The present study was designed to evaluate the anti-cancer effects of PAB on hepatocellular carcinoma (HCC) cell lines in vitro, and to explore the underlying mechanism.

METHODS

The anti-proliferative activity of PAB on HCC cells were assessed via sulforhodamine B staining, colony formation, cell cycle analysis, respectively. Apoptosis was detected using Annexin V/propidium iodide double staining and diamidino-phenyl-indole staining, respectively. Protein expression regulated by PAB treatment was tested by western blotting.

RESULTS

The present results showed that PAB significantly inhibited the proliferation of HepG2, SK-Hep-1, and Huh-7 HCC cell lines in vitro with IC₅₀ values of 1.58, 1.90, and 2.06 μM, respectively. Furthermore, PAB treatment repressed the colony formation in HepG2, SK-Hep-1, and Huh-7 HCC cell lines. Flow cytometry analysis revealed that PAB caused an obvious cell cycle arrest in G2/M phase and induced apoptosis with the induction of p21, Bax, cleaved-caspase-3, and cleaved-PARP in human HepG2 and SK-Hep-1 cells. Mechanistically, PAB treatment down-regulated the phosphorylation of STAT3, ERK1/2, and Akt. Moreover, abnormal GSK-3β/β-catenin signaling in HepG2 cells was remarkably suppressed by PAB treatment. Finally, proliferation markers including cyclin D1 and c-Myc, and anti-apoptosis proteins such as Bcl-2 and survivin were also down-regulated by PAB treatment in HepG2 cells.

CONCLUSION

Taken together, our results suggest that PAB exerts anti-cancer activity in HCC cells through inhibition of STAT3, ERK1/2, Akt, and GSK-3β/β-catenin carcinogenic signaling pathways, and may be used as a phytomedicine in the treatment of HCC.

Transcription factor GATA4 associates with mesenchymal-like gene expression in human hepatoblastoma cells

GATA4, a transcription factor crucial for early liver development, has been implicated in the pathophysiology of hepatoblastoma, an embryonal tumor of childhood. However, the molecular and phenotypic consequences of GATA4 expression in hepatoblastoma are not fully understood. We surveyed GATA4 expression in 24 hepatoblastomas using RNA in situ hybridization and immunohistochemistry. RNA interference was used to inhibit GATA4 in human HUH6 hepatoblastoma cells, and changes in cell migration were measured with wound healing and transwell assays. RNA microarray hybridization was performed on control and GATA4 knockdown HUH6 cells, and differentially expressed genes were validated by quantitative polymerase chain reaction or immunostaining. Plasmid transfection was used to overexpress GATA4 in primary human hepatocytes and ensuring changes in gene expression were measured by quantitative polymerase chain reaction. We found that GATA4 expression was high in most hepatoblastomas but weak or negligible in normal hepatocytes. GATA4 gene silencing impaired HUH6 cell migration. We identified 106 differentially expressed genes (72 downregulated, 34 upregulated) in knockdown versus control HUH6 cells. GATA4 silencing altered the expression of genes associated with cytoskeleton organization, cell-to-cell adhesion, and extracellular matrix dynamics (e.g. ADD3, AHNAK, DOCK8, RHOU, MSF, IGFBP1, COL4A2). These changes in gene expression reflected a more epithelial (less malignant) phenotype. Consistent with this notion, there was reduced F-actin stress fiber formation in knockdown HUH6 cells. Forced expression of GATA4 in primary human hepatocytes triggered opposite changes in the expression of genes identified by GATA4 silencing in HUH6 cells. In conclusion, GATA4 is highly expressed in most hepatoblastomas and correlates with a mesenchymal, migratory phenotype of hepatoblastoma cells.

Modulation of sonic hedgehog-induced mouse embryonic stem cell behaviours through E-cadherin expression and integrin β1-dependent F-actin formation

BACKGROUND AND PURPOSE

The sonic hedgehog pathway (Shh) plays a central role in maintaining stem cell function and behaviour in various processes related to self-renewal and tissue regeneration. However, the therapeutic effect of Shh on mouse embryonic stem cells (mESCs) has not yet been clearly elucidated. Thus, we investigated the effect of Shh on the regulation of mESC behaviour as well as the effect of Shh-pretreated mESCs in skin wound healing.

EXPERIMENTAL APPROACH

The underlying mechanisms of Shh signalling pathway in growth and motility of mESCs were investigated using Western blot analysis, a cell proliferation assay and cell migration assay. In addition, the effect of Shh-pretreated mESCs in skin wound healing was determined using a mouse excisional wound splinting model.

KEY RESULTS

Shh disrupted the adherens junction through proteolysis by activating MMPs. In addition, the release of β-catenin from adherens junctions mediated by Shh led to cell cycle-dependent mESC proliferation. Shh-mediated Gli1 expression led to integrin β1 up-regulation, followed by FAK and Src phosphorylation. Furthermore, among the Rho-GTPases, Rac1 and Cdc42 were activated in a Shh-dependent manner while F-actin expression was suppressed by Rac1 and Cdc42 siRNA transfection. Consistent with the in vitro results, the skin wound healing assay revealed that Shh-treated mESCs increased angiogenesis and skin wound repair compared to that in Shh-treated mESCs transfected with integrin β1 siRNA in vivo.

CONCLUSIONS AND IMPLICATIONS

Our results imply that Shh induces adherens junction disruption and integrin β1-dependent F-actin formation by a mechanism involving FAK/Src and Rac1/Cdc42 signalling pathways in mESCs.

Complex polymorphisms in endocytosis genes suggest alpha-cyclodextrin as a treatment for breast cancer

Most breast cancer deaths are caused by metastasis and treatment options beyond radiation and cytotoxic drugs, which have severe side effects, and hormonal treatments, which are or become ineffective for many patients, are urgently needed. This study reanalyzed existing data from three genome-wide association studies (GWAS) using a novel computational biostatistics approach (muGWAS), which had been validated in studies of 600-2000 subjects in epilepsy and autism. MuGWAS jointly analyzes several neighboring single nucleotide polymorphisms while incorporating knowledge about genetics of heritable diseases into the statistical method and about GWAS into the rules for determining adaptive genome-wide significance. Results from three independent GWAS of 1000-2000 subjects each, which were made available under the National Institute of Health's "Up For A Challenge" (U4C) project, not only confirmed cell-cycle control and receptor/AKT signaling, but, for the first time in breast cancer GWAS, also consistently identified many genes involved in endo-/exocytosis (EEC), most of which had already been observed in functional and expression studies of breast cancer. In particular, the findings include genes that translocate (ATP8A1, ATP8B1, ANO4, ABCA1) and metabolize (AGPAT3, AGPAT4, DGKQ, LPPR1) phospholipids entering the phosphatidylinositol cycle, which controls EEC. These novel findings suggest scavenging phospholipids as a novel intervention to control local spread of cancer, packaging of exosomes (which prepare distant microenvironment for organ-specific metastases), and endocytosis of β1 integrins (which are required for spread of metastatic phenotype and mesenchymal migration of tumor cells). Beta-cyclodextrins (βCD) have already been shown to be effective in in vitro and animal studies of breast cancer, but exhibits cholesterol-related ototoxicity. The smaller alpha-cyclodextrins (αCD) also scavenges phospholipids, but cannot fit cholesterol. An in-vitro study presented here confirms hydroxypropyl (HP)-αCD to be twice as effective as HPβCD against migration of human cells of both receptor negative and estrogen-receptor positive breast cancer. If the previous successful animal studies with βCDs are replicated with the safer and more effective αCDs, clinical trials of adjuvant treatment with αCDs are warranted. Ultimately, all breast cancer are expected to benefit from treatment with HPαCD, but women with triple-negative breast cancer (TNBC) will benefit most, because they have fewer treatment options and their cancer advances more aggressively.

Basolateral CD147 induces hepatocyte polarity loss by E-cadherin ubiquitination and degradation in hepatocellular carcinoma progress

Hepatocytes are epithelial cells with highly specialized polarity. The disorder and loss of hepatocyte polarity leads to a weakness of cell adhesion and connection, the induction of epithelial-mesenchymal transition, and eventually the occurrence of hepatocellular carcinoma (HCC). Cluster of differentiation 147 (CD147), a tumor-related glycoprotein, promotes epithelial-mesenchymal transition and the invasion of HCC. However, the function of CD147 in hepatocyte depolarization is unknown. Here we identified that CD147 was basolaterally polarized in hepatocyte membrane of liver tissues and HepG2 cells. CD147 not only promoted transforming growth factor-β1-mediated hepatocyte polarity loss but also directly induced endocytosis and down-regulation of E-cadherin which contributed to hepatocyte depolarization. Overexpression of CD147 induced Src activation and subsequently recruited ubiquitin ligase Hakai for E-cadherin ubiquitination and lysosomal degradation, leading to decreases of partitioning defective 3 expression and β-catenin nuclear translocation. This signal transduction was initiated by competitive binding of CD147 with integrin β1 that interrupted the interaction between the Arg-Gly-Asp motif of fibronectin and integrin β1. The specific antibodies targeting integrin α5 and β1 reversed the decrease of E-cadherin and partitioning defective 3 levels induced by CD147 overexpression. In human liver tissues, CD147 polarity rates significantly declined from liver cirrhosis (71.4%) to HCC (10.4%). CD147-polarized localization negatively correlated with Child-Pugh scores in human liver cirrhosis (r = -0.6092, P < 0.0001) and positively correlated with differentiation grades in HCC (r = 0.2060, P = 0.004). HCC patients with CD147-polarized localization had significantly better overall survival than patients with CD147 nonpolarity (P = 0.021).

CONCLUSION

The ectopic CD147-polarized distribution on basolateral membrane promotes hepatocyte depolarization by activation of the CD147-integrin α5β1-E-cadherin ubiquitination-partitioning defective 3 decrease and β-catenin translocation signaling cascade, replenishing a molecular pathway in hepatic carcinogenesis. (Hepatology 2018;68:317-332).

K15 Protein of Kaposi's Sarcoma Herpesviruses Increases Endothelial Cell Proliferation and Migration through Store-Operated Calcium Entry

Kaposi's sarcoma (KS) is a tumor of the vascular endothelium that is caused by Kaposi's sarcoma-associated herpesvirus (KSHV). K15 of KSHV is a specific gene encoding a transmembrane protein. Two highly different forms of K15, the predominant (K15P) and minor (K15M) have been identified in different KSHV strains. In genomic locations and protein topology, two K15 alleles resemble the latent membrane protein (LMP) 1 and LMP2A of Epstein⁻Barr virus. Both K15 proteins have motifs similar to those found in LMP1 and LMP2A. K15 therefore seems to be a hybrid of a distant evolutionary relative of LMP1 and LMP2A. Ca²⁺ is a second messenger and participates in numerous activities in cells, like proliferation, migration and metastasis. It has been found previously that LMP1 increased Ca²⁺ influx through store-operated calcium channels and blockade of LMP1 reduced store-operated Ca²⁺ entry (SOCE). LMP2A has similar activity. So we sought to determine whether K15 had similar activity. We showed that K15P induced Ca²⁺ influx and enhanced expression of Orail1, which is a vital protein in SOCE, and overexpression of K15P improved cell motility. Mutant K15P did not show these activities in HEK-293T and EA.hy 926 cells. Our results showed that K15P increased cell proliferation and migration though SOCE and established a novel mechanism for the development of KS and KSHV-associated diseases.

Dock8 regulates BCR signaling and activation of memory B cells via WASP and CD19

Dock8 deficiency leads to immunodeficiency, and the role of Dock8 in B-cell development and function has been revealed; however, the role of DocK8 on B-cell receptor (BCR) signaling and function of memory B cells remains elusive. In this study, we generated a Dock8 knockout mouse model and collected peripheral blood mononuclear cells from Dock8 patients to study the effect of Dock8 deficiency on the BCR signaling and activation of memory B cells with confocal microscopy and total internal reflection fluorescence microscopy. The activation of key, positive upstream BCR signaling molecules, pCD19 and phosphorylated Brutons tyrosine kinase (pBtk), is reduced. Interestingly, the total protein and activated levels of Wiskott-Aldrich syndrome protein (WASP) are decreased in Dock8-deficient mouse B cells. Our previous research has shown that WASP positively regulates cd19 transcription; furthermore, we found that Dock8 regulates cd19 transcription. What we found in Dock8 patients can be a phenotype copied from Dock8 mice. The early activation of memory B cells from Dock8 patients is disrupted with reduced BCR clustering, B-cell spreading, and signalosome recruitment into the degree of naïve B cells, as well as the transition from naïve B cells to unswitched memory B cells. Overall, our study provides a novel mechanism for Dock8 regulation of BCR signaling by regulating cd19 transcription, as well as the underlying mechanism of noncompetence of memory B cells in Dock8 patients.

The altered glucose metabolism in tumor and a tumor acidic microenvironment associated with extracellular matrix metalloproteinase inducer and monocarboxylate transporters

Extracellular matrix metalloproteinase inducer, also knowns as cluster of differentiation 147 (CD147) or basigin, is a widely distributed cell surface glycoprotein that is involved in numerous physiological and pathological functions, especially in tumor invasion and metastasis. Monocarboxylate transporters (MCTs) catalyze the proton-linked transport of monocarboxylates such as L-lactate across the plasma membrane to preserve the intracellular pH and maintain cell homeostasis. As a chaperone to some MCT isoforms, CD147 overexpression significantly contributes to the metabolic transformation of tumor. This overexpression is characterized by accelerated aerobic glycolysis and lactate efflux, and it eventually provides the tumor cells with a metabolic advantage and an invasive phenotype in the acidic tumor microenvironment. This review highlights the roles of CD147 and MCTs in tumor cell metabolism and the associated molecular mechanisms. The regulation of CD147 and MCTs may prove to be with a therapeutic potential for tumors through the metabolic modification of the tumor microenvironment.

Molecular targets and signaling pathways regulated by nuclear translocation of syndecan-1

Background

The cell-surface heparan sulfate proteoglycan syndecan-1 is important for tumor cell proliferation, migration, and cell cycle regulation in a broad spectrum of malignancies. Syndecan-1, however, also translocates to the cell nucleus, where it might regulate various molecular functions.

Results

We used a fibrosarcoma model to dissect the functions of syndecan-1 related to the nucleus and separate them from functions related to the cell-surface. Nuclear translocation of syndecan-1 hampered the proliferation of fibrosarcoma cells compared to the mutant lacking nuclear localization signal. The growth inhibitory effect of nuclear syndecan-1 was accompanied by significant accumulation of cells in the G0/G1 phase, which indicated a possible G1/S phase arrest.

We implemented multiple, unsupervised global transcriptome and proteome profiling approaches and combined them with functional assays to disclose the molecular mechanisms that governed nuclear translocation and its related functions. We identified genes and pathways related to the nuclear compartment with network enrichment analysis of the transcriptome and proteome. The TGF-β pathway was activated by nuclear syndecan-1, and three genes were significantly altered with the deletion of nuclear localization signal: EGR-1 (early growth response 1), NEK11 (never-in-mitosis gene a-related kinase 11), and DOCK8 (dedicator of cytokinesis 8). These candidate genes were coupled to growth and cell-cycle regulation. Nuclear translocation of syndecan-1 influenced the activity of several other transcription factors, including E2F, NFκβ, and OCT-1. The transcripts and proteins affected by syndecan-1 showed a striking overlap in their corresponding biological processes. These processes were dominated by protein phosphorylation and post-translation modifications, indicative of alterations in intracellular signaling. In addition, we identified molecules involved in the known functions of syndecan-1, including extracellular matrix organization and transmembrane transport.

Conclusion

Collectively, abrogation of nuclear translocation of syndecan-1 resulted in a set of changes clustering in distinct patterns, which highlighted the functional importance of nuclear syndecan-1 in hampering cell proliferation and the cell cycle. This study emphasizes the importance of the localization of syndecan-1 when considering its effects on tumor cell fate.

Electronic supplementary material

The online version of this article (10.1186/s12860-017-0150-z) contains supplementary material, which is available to authorized users.

"Stealth dissemination" of macrophage-tumor cell fusions cultured from blood of patients with pancreatic ductal adenocarcinoma

Here we describe isolation and characterization of macrophage-tumor cell fusions (MTFs) from the blood of pancreatic ductal adenocarcinoma (PDAC) patients. The MTFs were generally aneuploidy, and immunophenotypic characterizations showed that the MTFs express markers characteristic of PDAC and stem cells, as well as M2-polarized macrophages. Single cell RNASeq analyses showed that the MTFs express many transcripts implicated in cancer progression, LINE1 retrotransposons, and very high levels of several long non-coding transcripts involved in metastasis (such as MALAT1). When cultured MTFs were transplanted orthotopically into mouse pancreas, they grew as obvious well-differentiated islands of cells, but they also disseminated widely throughout multiple tissues in "stealth" fashion. They were found distributed throughout multiple organs at 4, 8, or 12 weeks after transplantation (including liver, spleen, lung), occurring as single cells or small groups of cells, without formation of obvious tumors or any apparent progression over the 4 to 12 week period. We suggest that MTFs form continually during PDAC development, and that they disseminate early in cancer progression, forming "niches" at distant sites for subsequent colonization by metastasis-initiating cells.

CD147 expression was positively linked to aggressiveness and worse prognosis of gastric cancer: a meta and bioinformatics analysis

CD147 (also named as Basigin or EMMPRIN) might promote cancer invasion and metastasis by inducing MMP and VEGF synthesis in tumor microenvironment. We performed a systematic meta and bioinformatics analysis through multiple online databases up to March 14, 2017. Up-regulated CD147 expression was found in gastric cancer, compared with normal mucosa (p < 0.05). The male patients with gastric cancer showed higher CD147 expression than the female ones (p < 0.0001). CD147 expression was positively correlated with tumor size, depth of invasion, lymph node metastasis, TNM staging and unfavorable prognosis of gastric cancer (p < 0.05). At mRNA level, CD147 expression was higher in intestinal-type and mixed-type gastric carcinomas than normal tissues (p < 0.05). CD147 mRNA expression was negatively associated with histological grading and dedifferentiation of gastric cancer (p < 0.05). A higher CD147 mRNA expression was negatively correlated with overall and progression-free survival rates of all cancer patients, even stratified by clinicopathological features (p < 0.05). These findings indicated that CD147 expression might be employed as a potential marker to indicate gastric carcinogenesis and subsequent progression, even prognosis.

Current Status of Dedicator of Cytokinesis-Associated Immunodeficiency: DOCK8 and DOCK2

DOCK8 deficiency is an autosomal recessive combined immunodeficiency disease associated with elevated IgE, atopy, recurrent sinopulmonary and cutaneous viral infections, and malignancy. The DOCK8 protein is critical for cytoskeletal organization, and deficiency impairs dendritic cell transmigration, T-cell survival, and NK cell cytotoxicity. Early hematopoietic stem cell transplantation is gaining prominence as a definitive treatment given the potential for severe complications and mortality in this disease. Recently, DOCK2 deficiency has been identified in several patients with early-onset invasive bacterial and viral infections.

A novel small-molecule compound targeting CD147 inhibits the motility and invasion of hepatocellular carcinoma cells

CD147, a type I transmembrane glycoprotein, is highly expressed in various cancer types and plays important roles in tumor progression, especially by promoting the motility and invasion of hepatocellular carcinoma (HCC) cells. These crucial roles make CD147 an attractive target for therapeutic intervention in HCC, but no small-molecule inhibitors of CD147 have been developed to date. To identify a candidate inhibitor, we used a pharmacophore model derived from the structure of CD147 to virtually screen over 300,000 compounds. The 100 highest-ranked compounds were subjected to biological assays, and the most potent one, dubbed AC-73 (ID number: AN-465/42834501), was studied further. We confirmed that AC-73 targeted CD147 and further demonstrated it can specifically disrupt CD147 dimerization. Moreover, molecular docking and mutagenesis experiments showed that the possible binding sites of AC-73 on CD147 included Glu64 and Glu73 in the N-terminal IgC2 domain, which two residues are located in the dimer interface of CD147. Functional assays revealed that AC-73 inhibited the motility and invasion of typical HCC cells, but not HCC cells that lacked the CD147 gene, demonstrating on-target action. Further, AC-73 reduced HCC metastasis by suppressing matrix metalloproteinase (MMP)-2 via down-regulation of the CD147/ERK1/2/signal transducer and activator of transcription 3 (STAT3) signaling pathway. Finally, AC-73 attenuated progression in an orthotopic nude mouse model of liver metastasis, suggesting that AC-73 or its derivatives have potential for use in HCC intervention. We conclude that the novel small-molecule inhibitor AC-73 inhibits HCC mobility and invasion, probably by disrupting CD147 dimerization and thereby mainly suppressing the CD147/ERK1/2/STAT3/MMP-2 pathways, which are crucial for cancer progression.

CD147 regulates cancer migration via direct interaction with Annexin A2 and DOCK3-β-catenin-WAVE2 signaling

The acquisition of inappropriate migratory feature is crucial for tumor metastasis. It has been suggested that CD147 and Annexin A2 are involved in regulating tumor cell movement, while the regulatory mechanisms are far from clear. In this study, we demonstrated that CD147 physically interacted with the N-terminal domain of Annexin A2 and decreased Annexin A2 phosphorylation on tyrosine 23. In vitro kinase assay showed that the I domain of CD147 was indispensable for CD147-mediated downregulation of Annexin A2 phosphorylation by Src. Furthermore, we determined that p-Annexin A2 promoted the expression of dedicator of cytokinesis 3 (DOCK3) and DOCK3 blocked β-catenin nuclear translocation, resulting in inhibition of β-catenin signaling. In addition, DOCK3 inhibited lamellipodium dynamics and tumor cell movement. Also, we found that β-catenin signaling increased WAVE2 expression. Therefore, DOCK3 was characterized as a negative regulator of WAVE2 expression via inhibiting β-catenin signaling. Our study provides the first evidence that CD147 promotes tumor cell movement and metastasis via direct interaction with Annexin A2 and DOCK3-β-catenin-WAVE2 signaling axis.

Comprehensive analysis of the long noncoding RNA HOXA11-AS gene interaction regulatory network in NSCLC cells

Background

Long noncoding RNAs (lncRNAs) are related to different biological processes in non-small cell lung cancer (NSCLC). However, the possible molecular mechanisms underlying the effects of the long noncoding RNA HOXA11-AS (HOXA11 antisense RNA) in NSCLC are unknown.

Methods

HOXA11-AS was knocked down in the NSCLC A549 cell line and a high throughput microarray assay was applied to detect changes in the gene profiles of the A549 cells. Bioinformatics analyses (gene ontology (GO), pathway, Kyoto Encyclopedia of Genes and Genomes (KEGG), and network analyses) were performed to investigate the potential pathways and networks of the differentially expressed genes. The molecular signatures database (MSigDB) was used to display the expression profiles of these differentially expressed genes. Furthermore, the relationships between the HOXA11-AS, de-regulated genes and clinical NSCLC parameters were verified by using NSCLC patient information from The Cancer Genome Atlas (TCGA) database. In addition, the relationship between HOXA11-AS expression and clinical diagnostic value was analyzed by receiver operating characteristic (ROC) curve.

Results

Among the differentially expressed genes, 277 and 80 genes were upregulated and downregulated in NSCLC, respectively (fold change ≥2.0, P < 0.05 and false discovery rate (FDR) < 0.05). According to the degree of the fold change, six upregulated and three downregulated genes were selected for further investigation. Only four genes (RSPO3, ADAMTS8, DMBT1, and DOCK8) were reported to be related with the development or progression of NSCLC based on a PubMed search. Among all possible pathways, three pathways (the PI3K-Akt, TGF-beta and Hippo signaling pathways) were the most likely to be involved in NSCLC development and progression. Furthermore, we found that HOXA11-AS was highly expressed in both lung adenocarcinoma and squamous cell carcinoma based on TCGA database. The ROC curve showed that the area under curve (AUC) of HOXA11-AS was 0.727 (95% CI 0.663–0.790) for lung adenocarcinoma and 0.933 (95% CI 0.906–0.960) for squamous cell carcinoma patients. Additionally, the original data from TCGA verified that ADAMTS8, DMBT1 and DOCK8 were downregulated in both lung adenocarcinoma and squamous cell carcinoma, whereas RSPO3 expression was upregulated in lung adenocarcinoma and downregulated in lung squamous cell carcinoma. For the other five genes (STMN2, SPINK6, TUSC3, LOC100128054, and C8orf22), we found that STMN2, TUSC3 and C8orf22 were upregulated in squamous cell carcinoma and that STMN2 and USC3 were upregulated in lung adenocarcinoma. Furthermore, we compared the correlation between HOXA11-AS and de-regulated genes in NSCLC based on TCGA. The results showed that the HOXA11-AS expression was negatively correlated with DOCK8 in squamous cell carcinoma (r = −0.124, P = 0.048) and lung adenocarcinoma (r = −0.176, P = 0.005). In addition, RSPO3, ADAMTS8 and DOCK8 were related to overall survival and disease-free survival (all P < 0.05) of lung adenocarcinoma patients in TCGA.

Conclusions

Our results showed that the gene profiles were significantly changed after HOXA11-AS knock-down in NSCLC cells. We speculated that HOXA11-AS may play an important role in NSCLC development and progression by regulating the expression of various pathways and genes, especially DOCK8 and TGF-beta pathway. However, the exact mechanism should be verified by functional experiments.

N-linked glycosylation at Asn152 on CD147 affects protein folding and stability: promoting tumour metastasis in hepatocellular carcinoma

Cluster of differentiation 147 (CD147), also known as extracellular matrix metalloproteinase inducer, is a transmembrane glycoprotein that mediates oncogenic processes partly through N-glycosylation modifications. N-glycosylation has been demonstrated to be instrumental for the regulation of CD147 function during malignant transformation. However, the role that site-specific glycosylation of CD147 plays in its defective function in hepatocellular carcinomacells needs to be determined. Here, we demonstrate that the modification of N-glycosylation at Asn152 on CD147 strongly promotes hepatocellular carcinoma (HCC) invasion and migration. After the removal of N-glycans at Asn152, CD147 was more susceptible to degradation by ER-localized ubiquitin ligase-mediated endoplasmic reticulum-associated degradation (ERAD). Furthermore, N-linked glycans at Asn152 were required for CD147 to acquire and maintain proper folding in the ER. Moreover, N-linked glycans at Asn152 functioned as a recognition motif that was directly mediated by the CNX quality control system. Two phases in the retention-based ER chaperones system drove ER-localized CD147 trafficking to degradation. Deletion of N-linked glycosylation at Asn152 on CD147 significantly suppressed in situ tumour metastasis. These data could potentially shed light on the molecular regulation of CD147 through glycosylation and provide a valuable means of developing drugs that target N-glycans at Asn152 on CD147.

Long non-coding RNA linc-cdh4-2 inhibits the migration and invasion of HCC cells by targeting R-cadherin pathway

Long non-coding RNAs (LncRNAs) have played very important roles in the malignancy behaviors of hepatocellular carcinoma (HCC). Linc-cdh4-2 (TCONS_00027978) is a novel LncRNA that has been identified in HCC tissues from our previous study. Overexpression of linc-cdh4-2 in HCC cell lines (SK-Hep-1 and Huh7) significantly decreases the migration and invasion abilities of these cells, while knockdown the expression of linc-cdh4-2 significantly increases the migration and invasion abilities. Interestingly, neither the over expression nor the knock down of linc-cdh4-2 could affect the viability and proliferation of HCC cells. Mechanistically, the linc-cdh4-2 could up-regulate the protein level of R-cadherin through direct binding that might improve the protein stability. Over expression of linc-cdh4-2 could significantly increase the protein levels of R-cadherin and decrease the protein levels of small GTPase RAC1, and vice-versa. Further knockdown R-cadherin in linc-cdh4-2 stably overexpressed cells, could significantly upregulate the protein levels of RAC1 and improve the cell migration and invasion abilities. Taken together, the novel linc-cdh4-2 may negatively regulate the motility of the HCC cells through targeting R-cadherin-RAC1 signaling pathway.

GB virus type C E2 protein inhibits human immunodeficiency virus type 1 Gag assembly by downregulating human ADP-ribosylation factor 1

GB virus type C (GBV-C) glycoprotein E2 protein disrupts HIV-1 assembly and release by inhibiting Gag plasma membrane targeting, however the mechanism by which the GBV-C E2 inhibits Gag trafficking remains unclear. In the present study, we identified ADP-ribosylation factor 1 (ARF1) contributed to the inhibitory effect of GBV-C E2 on HIV-1 Gag membrane targeting. Expression of GBV-C E2 decreased ARF1 expression in a proteasomal degradation-dependent manner. The restoration of ARF1 expression rescued the HIV-1 Gag processing and membrane targeting defect imposed by GBV-C E2. In addition, GBV-C E2 expression also altered Golgi morphology and suppressed protein traffic through the secretory pathway, which are all consistent with a phenotype of disrupting the function of ARF1 protein. Thus, our results indicate that GBV-C E2 inhibits HIV-1 assembly and release by decreasing ARF1, and may provide insights regarding GBV-C E2's potential for a new therapeutic approach for treating HIV-1.

CD147 promotes cell motility via upregulation of p190-B RhoGAP in hepatocellular carcinoma

BACKGROUND

The acquisition of inappropriate migratory feature is crucial for tumor metastasis. Rho-family GTPases including RhoA are molecular switches that play critical roles in regulating cell movement. We investigated the molecular mechanism underlying CD147 induced RhoA deactivation in hepatocellular carcinoma (HCC) cells.

METHODS

Wound-healing assay was performed to study the cell motility. Analysis of RhoA activation in living cells was conducted using RhoA biosensor. Changes in the expression of certain genes were determined by quantitative real-time PCR. The expression of proteins was evaluated by Western blot. Cytoskeleton reorganization and focal adhesion formation were observed by immunofluorescence staining. Further investigation on the correlation between CD147 and p190-B RhoGAP (p190-B) in HCC tissues was performed by immunological histological chemistry analysis.

RESULTS

CD147 promoted cell movement and suppressed RhoA activation. p190-B, a negative regulator of RhoA activity, was upregulated by CD147 at both mRNA and protein levels. This regulatory relationship was further confirmed by analyzing the expression pattern of CD147 and p190-B in human HCC tissues. Silencing of p190-B caused the increased formation of stress fiber and focal adhesion and blunted the impact of CD147 overexpression on cell movement, indicating that the regulatory effect of CD147 on cell movement is mediated, at least partially, by p190-B.

CONCLUSIONS

These findings indicated that p190-B, a negative regulator of RhoA, is positively regulated by CD147 and contributes to the regulation of cell movement in HCC. CD147 plays critical roles in the motility of cancer cells and may be therefore a valuable drug target for anti-cancer therapy.

Inhibition of STAT3 reduces proliferation and invasion in salivary gland adenoid cystic carcinoma

In this study, we accessed the expression and correlation of p-STAT3 with Survivin, Cyclin D1, CD147, Slug and Ki67 by immunohistochemical staining of human tissue microarray which contains 72 adenoid cystic carcinoma (AdCC), 12 pleomorphic adenoma (PMA) and 18 normal salivary gland (NSG) using digital pathological scanner and scoring system. We found that the expression of p-STAT3, Survivin, Slug, Cyclin D1 and CD147 was significantly increased in AdCC as compared with PMA and (or) NSG (p<0.05). While, the level of p-STAT3 and expression of Cyclin D1 and CD147 was not associated with pathological type of human AdCC (p>0.05). Correlation analysis of these proteins revealed that p-STAT3 up-regulates the expression of Survivin, Slug, Cyclin D1 and CD147 (p<0.05). Moreover, the activation of STAT3 was associated with proliferation marker Ki-67 (p<0.05). Selective inhibition of STAT3 by a small molecule S3I-201 significantly reduced human SACC-83 and SACC-LM cells proliferation, migration and invasion with the corresponding decrease in expression of Survivin, Slug, Cyclin D1 and CD147. These findings indicate that high phosphorylation level of STAT3 in AdCC is related to Survivin, Slug, Cyclin D1 and CD147. We suggest that the inhibition of STAT3 may be a novel strategy for neoadjuvant chemotherapeutic treatment of AdCC.