Binding of multivalent CD147 phage induces apoptosis of U937 cells

Generation and Characterization of Fibroblast-Specific Basigin Knockout Mice

Basigin is a well-known extracellular stimulator of fibroblasts and may confer resistance to apoptosis of fibroblasts in vitro under some pathological status, but its exact function in fibroblasts and the underlying mechanism remain poorly understood. The systematic Basigin gene knockout leads to the perinatal lethality of mice, which limits the delineation of its function in vivo. In this study, we generated a fibroblast-specific Basigin knock-out mouse model and demonstrated the successful deletion of Basigin in fibroblasts. The fibroblast-specific deletion of Basigin did not influence the growth, fertility and the general condition of the mice. No obvious differences were found in the size, morphology, and histological structure of the major organs, including heart, liver, spleen, lung and kidney, between the knockout mice and the control mice. The deletion of Basigin in fibroblasts did not induce apoptosis in the tissues of the major organs. These results provide the first evidence that the fibroblast-specific Basigin knock-out mice could be a useful tool for exploring the function of Basigin in fibroblasts in vivo.

Potent inhibition of OKT3-induced T cell proliferation and suppression of CD147 cell surface expression in HeLa cells by scFv-M6-1B9

CD147, a multifunctional type I transmembrane glycoprotein, has been implicated in various physiological and pathological processes. It is involved in signal transduction pathways and also plays a crucial role in the invasive and metastatic activity of malignant tumor cells. Diminished expression of this molecule has been shown to be beneficial in suppression of tumor progression. In a previous study, we generated and characterized a recombinant antibody fragment, scFv, which reacted specifically to CD147. In the present study, we further investigated the biological properties, function and the effect of generated scFv on CD147 expression. The in vitro study showed that soluble scFv-M6-1B9 produced from E. coli HB2151 bound to CD147 surface molecule and inhibited OKT3-induced T cell proliferation. Furthermore, soluble lysate of scFv-M6-1B9 from 293A cells, transduced with a scFv-M6-1B9 expressing adenovirus vector, recognized both recombinant and native CD147. These results indicate that scFv-M6-1B9 binds with high efficiency and specificity. Importantly, scFv-M6-1B9 intrabody reduced the expression of CD147 on the cell surface of HeLa cells suggesting that scFv-M6-1B9 is biologically active. In conclusion, our present study demonstrated that scFv-M6-1B9 has a great potential to target both the intracellular and the extracellular CD147. The generated scFv-M6-1B9 may be an effective agent to clarify the cellular function of CD147 and may aid in efforts to develop a novel treatment in various human carcinomas.

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.

Recombinant Multivalent EMMPRIN Extracellular Domain Induces U937 Human Leukemia Cell Apoptosis by Downregulation of Monocarboxylate Transporter 1 and Activation of Procaspase-9

This study was carried out to understand the effect of the recombinant multivalent extracellular matrix metalloproteinase inducer (EMMPRIN) extracellular domain, designated as rmEMMPRINex, on the apoptotic cell death of human leukemia U937 cells. Expression of monocarboxylate transporter 1 (MCT1) and caspase-9 in U937 treated with rmEMMPRINex was investigated in this study. Levels of membrane MCT1 and intracellular procaspase-9 were decreased in rmEMMPRINex-treated cells in comparison to controls. However, the expression of activated caspase-9 was undetectable. rmEMMPRINex also induced DNA fragmentation and apoptosis in U937 cells. Taken together, we concluded that interaction of rmEMMPRINex with U937 cells leads to inhibition of MCT1 membrane expression, intracellular activation of procaspase-9, followed by DNA fragmentation and apoptosis. This may contribute to the conceptual development of novel cancer drugs in the future.

New insights into germ cell migration and survival/apoptosis in spermatogenesis: Lessons from CD147

CD147, also named basigin (Bsg) or extracellular matrix (ECM) metalloproteinase inducer (EMMPRIN), is a highly glycosylated protein first identified as a tumor cell surface molecule. In cancer, it is well established that CD147 promotes metastasis by stimulating the production of MMPs. Recent studies have also suggested that it may be associated with tumor growth and angiogenesis. Interestingly, CD147 is expressed in germ cells of different development stages in the testis and its knockout mice are infertile, indicating an essential role of CD147 in spermatogenesis. While the detailed involvement of CD147 in spermatogenesis remains elusive, our recent findings have revealed a dual role of CD147 in germ cell development. On the one hand, it regulates the migration of spermatogonia and spermatocytes via the induction of MMP-2 production; on the other hand, it specifically regulates the survival/apoptosis of spermatocytes but not spermatogonia through a p53-independent pathway. In this review, we aim to provide an overview on the functions of CD147, comparing its roles in cancer and the testis, thereby providing new insights into the regulatory mechanisms underlying the process of spermatogenesis.

Upregulation of HAb18G/CD147 in activated human umbilical vein endothelial cells enhances the angiogenesis

Previous studies demonstrated that CD147 molecule, highly expressed on the surface of various malignant tumor cells, significantly correlated with the malignancy of these cancers; however, the role of HAb18G/CD147 in endothelial cells has yet to be established. In this study, we found that the expression of HAb18G/CD147 was significantly upregulated in activated HUVECs. The inhibition of HAb18G/CD147 expression by specific siRNA led to significantly decreased angiogenesis in vitro. Our data indicate that HAb18G/CD147 may regulate angiogenesis via several mechanisms including proliferation, survival, migration, MMPs secretion, and PI3K/Akt activation. Our findings for the first time suggest that upregulation of HAb18G/CD147 in activated HUVECs might play an important role in angiogenesis.

Inhibition of CD147 gene expression via RNA interference reduces tumor cell proliferation, activation, adhesion, and migration activity in the human Jurkat T-lymphoma cell line

CD147, a leukocyte surface molecule over-expressed in T-lymphoma cells, is reportedly associated with lymphocyte activation and proteinase production via interactions with fibroblasts and plays a role in stromal invasion by lymphoma cells. To determine the role of CD147 in the progression of T-lymphoma, we performed siRNA interference-mediated knockdown of CD147 in a CD147-expressing Jurkat T-cell line. CD147 knockdown resulted in the decreased proliferation and migration of Jurkat cells and reduced the adhesion of Jurkat cells to extracelluar matrix fibronectin in vitro. CD147-siRNA inhibited the activation of Jurkat cells via down-regulation of CD25 expression. Our results indicate that CD147 is involved in T-lymphoma progression, a finding useful in efforts to develop targeted therapies to treat patients with T-lymphoma.

Generation of functional scFv intrabody to abate the expression of CD147 surface molecule of 293A cells

BACKGROUND

Expression of intracellular antibodies (intrabodies) has become a broadly applicable technology for generation of phenotypic knockouts in vivo. The method uses surface depletion of cellular membrane proteins to examine their biological function. In this study, we used this strategy to block the transport of cell surface molecule CD147 to the cell membrane. Phage display technology was introduced to generate the functional antibody fragment to CD147, and we subsequently constructed a CD147-specific scFv that was expressed intracellularly and retained in the endoplasmic reticulum by adenoviral gene transfer.

RESULTS

The recombinant antibody fragments, Fab and scFv, of the murine monoclonal antibody (clone M6-1B9) reacted specifically to CD147 by indirect enzyme-linked immunosorbent assays (ELISA) using a recombinant CD147-BCCP as a target. This indicated that the Fab- and scFv-M6-1B9 displaying on phage surfaces were correctly folded and functionally active. We subsequently constructed a CD147-specific scFv, scFv-M6-1B9-intrabody, in 293A cells. The expression of CD147 on 293A cell surface was monitored at 36 h after transduction by flow cytometry and demonstrated remarkable reduction. Colocalization of scFv-M6-1B9 intrabody with CD147 in the ER network was depicted using a 3D deconvolution microscopy system.

CONCLUSION

The results suggest that our approach can generate antibody fragments suitable for decreasing the expression of CD147 on 293A cells. This study represents a step toward understanding the role of the cell surface protein, CD147.