Downregulation of CD147 expression alters cytoskeleton architecture and inhibits gelatinase production and SAPK pathway in human hepatocellular carcinoma cells

RBC membrane biomechanics and Plasmodium falciparum invasion: probing beyond ligand-receptor interactions

A critical step in malaria blood-stage infections is the invasion of red blood cells (RBCs) by merozoite forms of the Plasmodium parasite. Much progress has been made in defining the parasite ligands and host receptors that mediate this critical step. However, less well understood are the RBC biophysical determinants that influence parasite invasion. In this review we explore how Plasmodium falciparum merozoites interact with the RBC membrane during invasion to modulate RBC deformability and facilitate invasion. We further highlight RBC biomechanics-related polymorphisms that might have been selected for in human populations due to their ability to reduce parasite invasion. Such an understanding will reveal the translational potential of targeting host pathways affecting RBC biomechanical properties for the treatment of malaria.

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.

Arf6-driven endocytic recycling of CD147 determines HCC malignant phenotypes

BACKGROUND

Adhesion molecules distributed on the cell-surface depends upon their dynamic trafficking that plays an important role during cancer progression. ADP-ribosylation factor 6 (Arf6) is a master regulator of membrane trafficking. CD147, a tumor-related adhesive protein, can promote the invasion of liver cancer. However, the role of Arf6 in CD147 trafficking and its contribution to liver cancer progression remain unclear.

METHODS

Stable liver cancer cell lines with Arf6 silencing and over-expression were established. Confocal imaging, flow cytometry, biotinylation and endomembrane isolation were used to detect CD147 uptake and recycling. GST-pull down, gelatin zymography, immunofluorescence, cell adhesion, aggregation and tight junction formation, Transwell migration, and invasion assays were used to examine the cellular phenotypes. GEPIA bioinformatics, patient's specimens and electronic records collection, and immunohistochemistry were performed to obtain the clinical relevance for Arf6-CD147 signaling.

RESULTS

We found that the endocytic recycling of CD147 in liver cancer cells was controlled by Arf6 through concurrent Rab5 and Rab22 activation. Disruption of Arf6-mediated CD147 trafficking reduced the cell-matrix and cell-cell adhesion, weakened cell aggregation and junction stability, attenuated MMPs secretion and cytoskeleton reorganization, impaired HGF-stimulated Rac1 activation, and markedly decreased the migration and invasion of liver cancer cells. Moreover, high-expression of the Arf6-CD147 signaling components in HCC (hepatocellular carcinoma) was closely correlated with poor clinical outcome of patients.

CONCLUSIONS

Our results revealed that Arf6-mediated CD147 endocytic recycling is required for the malignant phenotypes of liver cancer. The Arf6-driven signaling machinery provides excellent biomarkers or therapeutic targets for the prevention of liver cancer.

Listeria monocytogenes hijacks CD147 to ensure proper membrane protrusion formation and efficient bacterial dissemination

Efficient cell-to-cell transfer of Listeria monocytogenes (L. monocytogenes) requires the proper formation of actin-rich membrane protrusions. To date, only the host proteins ezrin, the binding partner of ezrin, CD44, as well as cyclophilin A (CypA) have been identified as crucial components for L. monocytogenes membrane protrusion stabilization and, thus, efficient cell-to-cell movement of the microbes. Here, we examine the classical binding partner of CypA, CD147, and find that this membrane protein is also hijacked by the bacteria for their cellular dissemination. CD147 is enriched at the plasma membrane surrounding the membrane protrusions as well as the resulting invaginations generated in neighboring cells. In cells depleted of CD147, these actin-rich structures appear similar to those generated in CypA depleted cells as they are significantly shorter and more contorted as compared to their straighter counterparts formed in wild-type control cells. The presence of malformed membrane protrusions hampers the ability of L. monocytogenes to efficiently disseminate from CD147-depleted cells. Our findings uncover another important host protein needed for L. monocytogenes membrane protrusion formation and efficient microbial dissemination.

Distribution of CD147 During Enteropathogenic Escherichia coli and Salmonella enterica Serovar Typhimurium Infections

Enteropathogenic Escherichia coli (EPEC) and Salmonella enterica serovar Typhimurium (S. Typhimurium) are highly infectious gastrointestinal human pathogens. These microbes inject bacterial-derived effector proteins directly into the host cell cytosol as part of their disease processes. A common host subcellular target of these pathogens is the actin cytoskeleton, which is commandeered by the bacteria and is used during their attachment onto (EPEC) or invasion into (S. Typhimurium) the host cells. We previously demonstrated that the host enzyme cyclophilin A (CypA) is recruited to the actin-rich regions of EPEC pedestals and S. Typhimurium membrane ruffles. To further expand the growing catalogue of host proteins usurped by actin-hijacking bacteria, we examined the host plasma membrane protein and cognate receptor of CypA, CD147, during EPEC and S. Typhimurium infections. Here, we show that CD147 is enriched at the basolateral regions of pedestals but, unlike CypA, it is absent from their actin-rich core. We show that the CD147 recruitment to these areas requires EPEC pedestal formation and not solely bacteria-host cell contact. Additionally, we demonstrate that the depletion of CD147 by siRNA does not alter the formation of pedestals. Finally, we show that CD147 is also a component of actin-rich membrane ruffles generated during S. Typhimurium invasion of host cells. Collectively, our findings establish CD147 as another host component present at dynamic actin-rich structures formed during bacterial infections. Anat Rec, 302:2224-2232, 2019. © 2019 American Association for Anatomy.

Role of C-Jun N-terminal Kinase in Hepatocellular Carcinoma Development

Hepatocellular carcinoma (HCC) is among the most frequently occurring cancers and the leading causes of cancer mortality worldwide. Identification of the signaling pathways regulating liver carcinogenesis is critical for developing novel chemoprevention and targeted therapies. C-Jun N-terminal kinase (JNK) is a member of a larger group of serine/threonine (Ser/Thr) protein kinases known as the mitogen-activated protein kinase (MAPK) family. JNK is an important signaling component that converts external stimuli into a wide range of cellular responses, including cell proliferation, differentiation, survival, migration, invasion, and apoptosis, as well as the development of inflammation, fibrosis, cancer growth, and metabolic diseases. Because of the essential roles of JNK in these cellular functions, deregulated JNK is often found to contribute to the development of HCC. Recently, the functions and molecular mechanisms of JNK in HCC development have been addressed using mouse models and human HCC cell lines. Furthermore, recent studies demonstrate that the activation of JNK by oncogenes can promote the development of cancers by regulating the transforming growth factor (TGF)-β/Smad pathway, which makes the oncogenes/JNK/Smad signaling pathway an attractive target for cancer therapy. Additionally, JNK-targeted therapy has a broad potential for clinical applications. In summary, we are convinced that promising new avenues for the treatment of HCC by targeting JNK are on the horizon, which will undoubtedly lead to better, more effective, and faster therapies in the years to come.

Upregulation of CD147 Promotes Metastasis of Cholangiocarcinoma by Modulating the Epithelial-to-Mesenchymal Transitional Process

CD147 is a transmembrane protein that can induce the expression and activity of matrix metalloproteinases (MMPs). Expression of CD147 has been shown to potentiate cell migration, invasion, and metastasis of cancer. In this study, the critical role of CD147 in metastasis was elucidated using CD147-overexpressing cholangiocarcinoma (CCA) cells in vitro and in vivo. The molecular mechanism, demonstrated herein, supported the hypothesis that metastasis increased in CD147-overexpressing cells. Five CD147-overexpressing clones (Ex-CD147) were established from a low CD147-expressing CCA cell line, KKU-055, using lentivirus containing pReceiver-Lenti-CD147. The metastatic capability was determined using the tail vein injection mouse model and an in vitro 3D invasion assay. Liver colonization was assessed using anti-HLA class I immunohistochemistry. Adhesion abilities, cytoskeletal arrangements, MMP activities, the expressions of adhesion molecules, and epithelial-mesenchymal transitional markers were analyzed. All Ex-CD147 clones exhibited a high CD147 expression and high liver colonization in the tail vein-injected mouse model, whereas parental cells lacked this ability. Ex-CD147 clones exhibited metastatic phenotypes (i.e., an increase in F-actin rearrangement) and cell invasion and a decrease in cell adhesion. The molecular mechanisms were shown to be via the induction of MMP-2 activity and enhancement of epithelial-mesenchymal transitions. An increase in mesenchymal markers Slug, vimentin, and N-cadherin, and a decrease in epithelial markers E-cadherin and claudin-1, together with suppression of the adhesion molecule ICAM-1, were observed in the Ex-CD147 clones. Moreover, suppression of CD147 expression using siCD147 in two CCA cell lines with high CD147 expression significantly decreased cell migration and invasion of these CCA cells. These findings emphasize the essential role of CD147 in CCA metastasis and suggest CD147 as a promising target for the effective treatment of CCA.

Circulating CD147 predicts mortality in advanced hepatocellular carcinoma

BACKGROUND AND AIM

The glycoprotein CD147 has a role in tumor progression, is readily detectable in the circulation, and is abundantly expressed in hepatocellular carcinoma (HCC). Advanced HCC patients are a heterogeneous group with some individuals having dismal survival. The aim of this study was to examine circulating soluble CD147 levels as a prognostic marker in HCC patients.

METHODS

CD147 was measured in 277 patients (110 HCC, 115 chronic liver disease, and 52 non-liver disease). Clinical data included etiology, tumor progression, Barcelona Clinic Liver Cancer (BCLC) stage, and treatment response. Patients with HCC were stratified into two groups based upon the 75th percentile of CD147 levels (24 ng/mL).

RESULTS

CD147 in HCC correlated inversely with poor survival (P = 0.031). Increased CD147 predicted poor survival in BCLC stages C and D (P = 0.045), and CD147 levels >24 ng/mL predicted a significantly diminished 90-day and 180-day survival time (hazard ratio [HR] = 6.1; 95% confidence interval [CI]: 2.1-63.2; P = 0.0045 and HR = 2.8; 95% CI: 1.2-12.6; P = 0.028, respectively). In BCLC stage C, CD147 predicted prognosis; levels >24 ng/mL were associated with a median survival of 1.5 months compared with 6.5 months with CD147 levels ≤24 ng/mL (P = 0.03). CD147 also identified patients with a poor prognosis independent from treatment frequency, modality, and tumor size.

CONCLUSIONS

Circulating CD147 is an independent marker of survival in advanced HCC. CD147 requires further evaluation as a potential new prognostic measure in HCC to identify patients with advanced disease who have a poor prognosis.

CD147 reprograms fatty acid metabolism in hepatocellular carcinoma cells through Akt/mTOR/SREBP1c and P38/PPARα pathways

BACKGROUND & AIMS

CD147 is a transmembrane glycoprotein which is highly expressed in various human cancers including hepatocellular carcinoma (HCC). A drug Licartin developed with (131)Iodine-labeled antibody against CD147 has been approved by the Chinese Food and Drug Administration (FDA) and enters into clinical use for HCC treatment. Increasing lines of evidence indicate that CD147 is implicated in the metabolism of cancer cells, especially glycolysis. However, the molecular mechanism underlying the relationship between CD147 and aberrant tumor lipid metabolism remains elusive.

METHODS

We systematically investigated the role of CD147 in the regulation of lipid metabolism, including de novo lipogenesis and fatty acid β-oxidation, in HCC cells and explored the underlying molecular mechanisms.

RESULTS

Bioinformatic analysis and experimental evidence demonstrated that CD147 significantly contributed to the reprogramming of fatty acid metabolism in HCC cells mainly through two mechanisms. On one hand, CD147 upregulated the expression of sterol regulatory element binding protein 1c (SREBP1c) by activating the Akt/mTOR signaling pathway, which in turn directly activated the transcription of major lipogenic genes FASN and ACC1 to promote de novo lipogenesis. On the other hand, CD147 downregulated peroxisome proliferator-activated receptor alpha (PPARα) and its transcriptional target genes CPT1A and ACOX1 by activating the p38 MAPK signaling pathway to inhibit fatty acid β-oxidation. Moreover, in vitro and in vivo assays indicated that the CD147-mediated reprogramming of fatty acid metabolism played a critical role in the proliferation and metastasis of HCC cells.

CONCLUSION

Our findings demonstrate that CD147 is a critical regulator of fatty acid metabolism, which provides a strong line of evidence for this molecule to be used as a drug target in cancer treatment.

EtpE Binding to DNase X Induces Ehrlichial Entry via CD147 and hnRNP-K Recruitment, Followed by Mobilization of N-WASP and Actin

Obligate intracellular bacteria, such as Ehrlichia chaffeensis, perish unless they can enter eukaryotic cells. E. chaffeensis is the etiological agent of human monocytic ehrlichiosis, an emerging infectious disease. To infect cells, Ehrlichia uses the C terminus of the outer membrane invasin entry-triggering protein (EtpE) of Ehrlichia (EtpE-C), which directly binds the mammalian cell surface glycosylphosphatidyl inositol-anchored protein, DNase X. How this binding drives Ehrlichia entry is unknown. Here, using affinity pulldown of host cell lysates with recombinant EtpE-C (rEtpE-C), we identified two new human proteins that interact with EtpE-C: CD147 and heterogeneous nuclear ribonucleoprotein K (hnRNP-K). The interaction of CD147 with rEtpE-C was validated by far-Western blotting and coimmunoprecipitation of native EtpE with endogenous CD147. CD147 was ubiquitous on the cell surface and also present around foci of rEtpE-C-coated-bead entry. Functional neutralization of surface-exposed CD147 with a specific antibody inhibited Ehrlichia internalization and infection but not binding. Downregulation of CD147 by short hairpin RNA (shRNA) impaired E. chaffeensis infection. Functional ablation of cytoplasmic hnRNP-K by a nanoscale intracellular antibody markedly attenuated bacterial entry and infection but not binding. EtpE-C also interacted with neuronal Wiskott-Aldrich syndrome protein (N-WASP), which is activated by hnRNP-K. Wiskostatin, which inhibits N-WASP activation, and cytochalasin D, which inhibits actin polymerization, inhibited Ehrlichia entry. Upon incubation with host cell lysate, EtpE-C but not an EtpE N-terminal fragment stimulated in vitro actin polymerization in an N-WASP- and DNase X-dependent manner. Time-lapse video images revealed N-WASP recruitment at EtpE-C-coated bead entry foci. Thus, EtpE-C binding to DNase X drives Ehrlichia entry by engaging CD147 and hnRNP-K and activating N-WASP-dependent actin polymerization.

Ehrlichia chaffeensis, an obligate intracellular bacterium, causes a blood-borne disease called human monocytic ehrlichiosis, one of the most prevalent life-threatening emerging tick-transmitted infectious diseases in the United States. The survival of Ehrlichia bacteria, and hence, their ability to cause disease, depends on their specific mode of entry into eukaryotic host cells. Understanding the mechanism by which E. chaffeensis enters cells will create new opportunities for developing effective therapies to prevent bacterial entry and disease in humans. Our findings reveal a novel cellular signaling pathway triggered by an ehrlichial surface protein called EtpE to induce its infectious entry. The results are also important from the viewpoint of human cell physiology because three EtpE-interacting human proteins, DNase X, CD147, and hnRNP-K, are hitherto unknown partners that drive the uptake of small particles, including bacteria, into human cells.

Overexpression of CD147 in ovarian cancer is initiated by the hypoxic microenvironment

Ovarian cancer is a lethal malignant tumour characterised by activated invasion, distant metastasis, anti-cancer drug resistance, angiogenesis and metabolism. CD147, an extracellular matrix metalloproteinase inducer, is overexpressed in most ovarian tumours and plays an important role in the progression of ovarian cancer and other malignant tumours. However, the factor(s) initiating this overexpression is unknown. Because of rapid reproduction and their hypoxic microenvironment, malignant tumours use glycolysis for energy, and lactic acid produced is harmful to the cells. For survival, excessive lactate needs to be transported by monocarboxylate transporters (MCTs). Functioning of MCT1 and MCT4 require the ancillary of CD147. The gene for CD147 possesses two hypoxia-inducible factors binding sites in its 3'-flank. It is logical to postulate that the hypoxic microenvironment is a major initiator of the overexpression of CD147, thus conferring on ovarian cancers their malignant properties. A model that can represent spontaneous ovarian cancer is necessary to verify this hypothesis.

ERK1/2 signalling pathway is involved in CD147-mediated gastric cancer cell line SGC7901 proliferation and invasion

This study aimed to investigate the role of CD147 in the progression of gastric cancer and the signalling pathway involved in CD147-mediated gastric cancer cell line SGC7901 proliferation and invasion. Short hairpin RNA (shRNA) expression vectors targeting CD147 were constructed to silence CD147, and the expression of CD147 was monitored by quantitative realtime reverse transcriptase polymerase chain reaction and Western blot and further confirmed by immunohistochemistry in vivo. Cell proliferation was determined by Cell Counting Kit-8 assay, the activities of matrix metalloproteinase (MMP)-2 and MMP-9 were determined by gelatin zymography, and the invasion of SGC7901 was determined by invasion assay. The phosphorylation and non-phosphorylation of the mitogen-activated protein kinases, extracellular signal-regulated kinase1/2 (ERK1/2), P38 and c-Jun NH2-terminal kinase were examined by Western blot. Additionally, the ERK1/2 inhibitor U0126 were used to confirm the signalling pathway involved in CD147-mediated SGC7901 progression. The BALB/c nude mice were used to study tumour progression in vivo. The results revealed that CD147 silencing inhibited the proliferation and invasion of SGC7901 cells, and down-regulated the activities of MMP-2 and MMP-9 and the phosphorylation of the ERK1/2 in SGC7901 cells. ERK1/2 inhibitor U0126 decreased the proliferation, and invasion of SGC7901 cells, and down-regulated the MMP-2 and MMP-9 activities. In a nude mouse model of subcutaneous xenografts, the tumour volume was significantly smaller in the SGC7901/shRNA group compared to the SGC7901 and SGC7901/snc-RNA group. Immunohistochemistry analysis showed that CD147 and p-ERK1/2 protein expressions were down-regulated in the SGC7901/shRNA2 group compared to the SGC7901 and SGC7901/snc-RNA group. These results suggest that ERK1/2 pathway involves in CD147-mediated gastric cancer growth and invasion. These findings further highlight the importance of CD147 in cancer progression, indicating that CD147 would be an attractive therapeutic target for gastric cancer.

Regulation of invadopodia formation and activity by CD147

A defining feature of malignant tumor progression is cellular penetration through the basement membrane and interstitial matrices that separate various cellular compartments. Accumulating evidence supports the notion that invasive cells employ specialized structures termed invadopodia to breach these structural barriers. Invadopodia are actin-based, lipid-raft-enriched membrane protrusions containing membrane-type-1 matrix metalloproteinase (MT1-MMP; also known as matrix metalloproteinase 14; MMP14) and several signaling proteins. CD147 (emmprin, basigin), an immunoglobulin superfamily protein that is associated with tumor invasion and metastasis, induces the synthesis of various matrix metalloproteinases in many systems. In this study we show that upregulation of CD147 is sufficient to induce MT1-MMP expression, invasiveness and formation of invadopodia-like structures in non-transformed, non-invasive, breast epithelial cells. We also demonstrate that CD147 and MT1-MMP are in close proximity within these invadopodia-like structures and co-fractionate in membrane compartments with the properties of lipid rafts. Moreover, manipulation of CD147 levels in invasive breast carcinoma cells causes corresponding changes in MT1-MMP expression, invasiveness and invadopodia formation and activity. These findings indicate that CD147 regulates invadopodia formation and activity, probably through assembly of MT1-MMP-containing complexes within lipid-raft domains of the invadopodia.

CD147/EMMPRIN: an effective therapeutic target for hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is characterized by high resistance to conventional systemic therapies, rapid progression, easy metastasis and frequent recurrence. There is therefore an urgent requirement to develop novel systemic agents which specifically target hepatoma-associated antigen in the tumors of HCC patients. CD147, a transmembrane glycoprotein, is highly expressed by HCC cells and is strongly associated with HCC progression and prognosis. CD147 in HCC cells modulates HCC growth, promotes invasion and metastasis by stimulating adjacent fibroblasts and HCC cells to produce elevated levels of several extracellular matrix metalloproteinases (MMPs) in the HCC microenvironment. It is also involved in HCC angiogenesis and multidrug resistance (MDR). Clinical progress has been made in HCC treatment using CD147-directed monoclonal antibodies. Here, we give an overview of the literature regarding the molecular features and expression of CD147 in human HCC tissues. We specifically focus on the role of CD147 in HCC invasion and metastasis, as well as in angiogenesis and multidrug resistance. In addition, advances in therapeutic strategies targeting HCC CD147 are summarized.

Extracellular matrix metalloproteinase inducer: a novel poor prognostic marker for human seminomas

OBJECTIVE

Extracellular matrix metalloproteinase inducer (EMMPRIN) is a glycosylated member of the immunoglobulin superfamily whose function in human seminomas is unknown. We have recently determined that EMMPRIN possesses the ability to stimulate fibroblast and endothelial cell matrix metalloproteinase production, and that its expression was frequently up-regulated in several tumours of the urinary system. Thus, EMMPRIN expression might be associated with the progression of human seminomas. The aim of this study was to investigate whether the presence of EMMPRIN in seminoma tissues might help to predict the patients' prognosis.

METHODS

Paraffin-embedded tissues from 65 patients with seminomas and 20 normal testes were processed for immunohistochemical staining using a mouse monoclonal antibody generated against human EMMPRIN, as primary antibody, and a biotinylated goat-anti-mouse IgG, as secondary antibody. In addition, the correlation of EMMPRIN expression with clinicopathologic characteristics and patients' prognosis was also analysed.

RESULTS

EMMPRIN was detected in cancerous tissues of 53 patients with seminoma, but not normal testes. Thirty- five patients showed weakly to moderately positive and 18 patients intensely positive expression. Moreover, positive EMMPRIN staining correlated significantly with various clinicopathological factors (increased TNM stage and higher histological differentiation type) as well as decreased tumour-specific survival (log-rank, p=0.02). In particular, EMMPRIN expression was an independent prognosticator as shown by Cox regression analysis (p<0.001).

CONCLUSION

EMMPRIN expression in a primary tumour predicts an unfavourable prognosis in human seminoma, suggesting its crucial role in the progression of this tumour.

Clinical impact of HAb18G/CD147 expression in esophageal squamous cell carcinoma

BACKGROUND

HAb18G/CD147 expression has been associated with many tumor invasion molecules, which play important roles in recurrence and poor differentiation of esophageal squamous cell carcinoma (ESCC). However, the clinical implications of HAb18G/CD147 in ESCC are still unclear.

AIMS

In this study, we clarified the clinical significance of HAb18G/CD147 and characterized the association between HAb18G/CD147 and tumor invasion in ESCC cases.

METHODS

Tumor tissues were obtained from 86 ESCC patients who underwent surgical resection between 2002 and 2005. All patients that had received previous therapy were excluded. ESCC tissues were analyzed by IHC using anti HAb18G/CD147 antibody. The expression of HAb18G/CD147 mRNA in esophageal cancer cell lines was analyzed by RT-PCR.

RESULTS

HAb18G/CD147 was uniformly expressed in EC109 and EC871214 cell lines, but negatively expressed in EPC2, esophageal normal squamous cell line. HAb18G/CD147 mainly localized to the membrane of tumor cells in 84.9% of ESCC patients (64 out of 86 cases). Furthermore, we also found that higher HAb18G/CD147 expression levels significantly correlated with lymph node metastasis, depth of tumor invasion and differentiation (P < 0.05). But the expression levels of HAb18G/CD147 in lymph node metastatic tissues were almost equal to that in the primary tumor tissues. Furthermore, lymph node metastasis and expression of HAB18G/CD147 were independent prognostic indicators in ESCC.

CONCLUSIONS

The expression of HAb18G/CD147 might be involved in the progression and survival of ESCC. Therefore, HAb18G/CD147 could be a clinical marker for the poor prognosis in ESCC patients and may also be a potentially therapeutic target to improve the progression of ESCC.

Knockdown of ribonuclease inhibitor expression with siRNA in non-invasive bladder cancer cell line BIU-87 promotes growth and metastasis potentials

Human ribonuclease inhibitor (RI) is a cytoplasmic acidic protein. RI is constructed almost entirely of leucine-rich repeats, which might be involved in some unknown biological functions like other structurally similar proteins besides inhibiting RNase A and angiogenin activities. Our previous experiments demonstrated that up-regulating RI might effectively inhibit some tumor growth and metastasis. However, the down-regulating RI influence on the tumor does not have any report until now, the mechanisms underlying antitumor of RI have not been fully understood. In this study, the efficient RNA interferences of RI were constructed using a plasmid vector and identified with RT-PCR, Western blot and Immunocytochemistry, then were transfected into non-invasive bladder cancer BIU-87 cells. We demonstrated that knockdown RI expression in BIU-87 cells could obviously change the cell morphology, rearrange the microfilaments and extend the lamellipodia, as well as enhance proliferation, increase migration, invasion and matrix metalloprotease level, and also reduce adhesion in vitro. BALB/C nude mice that were injected with the BIU-87 cells transfected RI siRNA showed a significant facilitation of the tumor with heavier tumor weight, higher density of microvessels, lower nm23-H1 and E-Cadherin expressions than those in the control group. Taken together, these experiments suggest that knockdown of RI could promote growth and metastasis potentials of BIU-87 cells. Our present findings reveal the novel mechanism that anti-tumor effect of RI is also involved in suppressing growth and metastasis, besides antiangiogenesis. The results show that RI may be a therapeutic target protein for bladder cancer and may be of biological importance.

Lowered HGK expression inhibits cell invasion and adhesion in hepatocellular carcinoma cell line HepG2

AIM: To investigate the effects of RNA interference targeting hepatocyte progenitor kinase-like kinase (HGK) in the invasion and adhesion of hepatocellular carcinoma (HCC) cell line HepG2.

METHODS: Three paired insert DNA fragments specific to HGK gene and one negative control DNA fragment were synthesized and inserted into RNAi-Ready pSIREN-RetroQ-ZsGreen vector. Western blotting assay and real-time reverse transcriptase polymerase chain reaction (RT-PCR) were used to screen the vector with a highest inhibitory rate. The vector was used to generate recombinant retrovirus specific to HGK. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2h-tetrazolium bromide (MTT) assay was used to examine cell growth; wound closure assay and cell adhesion assay were employed to investigate cell migration and adhesion respectively; and transwell assay and three-dimensional culture invasion assay were used to detect cell invasion. The expressions of matrix metalloproteinase (MMP)-2, MMP-9 and nuclear factor (NF)-κB were detected by Western blotting assay.

RESULTS: The real time RT-PCR and Western blotting assay showed that cells transfected with retrovirus mediating RNAi targeting of HGK (RV-shHGK)-1 vector had the strongest inhibition of HGK protein, with an inhibition rate of 76%, and this vector was used to generate recombinant retrovirus RV-shHGK-1. Cell adhesion assay and MTT assay found that cell adhesion and growth of the cells infected with RV-shHGK-1 were significantly lower than those of the control cells (P < 0.05). Wound closure assay, transwell assay and three-dimensional culture invasion assay showed that the cell invasiveness was significantly less in HGK knockdown cells than in the control cells (P < 0.05). The expressions of MMP-2, MMP-9 and NF-κB were inhibited in HepG2 cells infected with RV-shHGK-1.

CONCLUSION: Down-regulation of HGK can obviously inhibit the migration and invasion of HepG2 cells in vitro. HGK may be a new therapeutic target for treatment of HCC.

Interaction of stellate cells with pancreatic carcinoma cells

Pancreatic cancer is characterized by its late detection, aggressive growth, intense infiltration into adjacent tissue, early metastasis, resistance to chemo- and radiotherapy and a strong “desmoplastic reaction”. The dense stroma surrounding carcinoma cells is composed of fibroblasts, activated stellate cells (myofibroblast-like cells), various inflammatory cells, proliferating vascular structures, collagens and fibronectin. In particular the cellular components of the stroma produce the tumor microenvironment, which plays a critical role in tumor growth, invasion, spreading, metastasis, angiogenesis, inhibition of anoikis, and chemoresistance. Fibroblasts, myofibroblasts and activated stellate cells produce the extracellular matrix components and are thought to interact actively with tumor cells, thereby promoting cancer progression. In this review, we discuss our current understanding of the role of pancreatic stellate cells (PSC) in the desmoplastic response of pancreas cancer and the effects of PSC on tumor progression, metastasis and drug resistance. Finally we present some novel ideas for tumor therapy by interfering with the cancer cell-host interaction.

A Competitive ELISA for quantifying serum CD147: reduction of soluble CD147 levels in cancer patient sera

CD147/EMMPRIN (extracellular matrix metalloproteinase inducer) is a cell surface glycoprotein that displays increased expression in many cancers. It has been previously demonstrated to participate in cancer metastasis and progression. In this study we used an anti-CD147 monoclonal antibody and a recombinant CD147 protein generated in our laboratory to establish a competitive ELISA for quantifying serum CD147 levels. Unexpectedly, the CD147 level was highest in sera of normal subjects and significantly reduced in sera of cancer patients. There was no significant difference in serum CD147 level between benign, non-metastatic, and metastatic stages of cancers. In regard to liver diseases, the maximal CD147 level was observed in sera of patients with hepatitis and hepatocellular carcinoma, and significantly decreased in patients with liver cirrhosis and cholangiocarcinoma. Our results imply that there may be homeostasis of CD147 levels in sera under normal physiological conditions, while such a level is altered in cancer patients.

Annexin II promotes invasion and migration of human hepatocellular carcinoma cells in vitro via its interaction with HAb18G/CD147

HAb18G/CD147, a member of the immunoglobulin family enriched on the surface of tumor cells, is reported to be correlated with invasion, metastasis, growth, and survival of malignant cells. Here, we found that annexin II, a 36-kDa Ca(2+)- and phospholipid-binding protein and in vivo substrate for tyrosine kinase and PKC, is a new interaction protein of HAb18G/CD147 in human hepatocellular carcinoma (HCC) cells. In the present study, we explored the unclear role of annxin II in HCC invasion and migration and the interaction effects between HAb18G/CD147 and annexin II. Our data show that downregulation of annexin II in HCC cells significantly decreased the secretion of MMP, migration ability, and invasive potential, and affected the cytoskeleton rearrangement of tumor cells. The MMP-2 level and invasive potential of HCC cells were regulated by both annexin II and HAb18G/CD147. Also, interaction effects exist between the two molecules in tumor progression, including MMP-2 production, migration, and invasion. These results suggest that annexin II promotes the invasion and migration of HCC cells in vitro, and annexin II and HAb18G/CD147 interact with each other in the same signal transduction pathway working as a functional complex in tumor progression.

Role and significance of focal adhesion proteins in hepatocellular carcinoma

Focal adhesions are structural links between the extracellular matrix and actin cytoskeleton. They are important sites where dynamic alterations of proteins in the focal contacts are involved during cell movement. Focal adhesions are composed of diverse molecules, for instance, receptors, structural proteins, adaptors, GTPase, kinases and phosphatases. These molecules play critical roles in normal physiological events such as cellular adhesion, movement, cytoskeletal structure and intracellular signaling pathways. In cancers, aberrant expression and altered functions of focal adhesion proteins contribute to adverse tumor behavior. It is evident that these proteins do not function alone, but rather associate and work together in the process of tumor development and cancer metastasis. Focal adhesion proteins have been shown to play critical roles in hepatocellular carcinoma. Understanding the molecular interactions and mechanisms of the interconnected focal adhesion proteins is of particular importance in understanding mechanisms underlying hepatocellular carcinoma progression and development of potential effective treatment.