Different patterns of human serum procollagen C-proteinase enhancer1 (PCPE1)

Procollagen C-proteinase enhancer-1 and renal failure in multiple myeloma

BACKGROUND

Renal involvement is present in approximately 50% of multiple myeloma (MM) cases and is associated with a poor prognosis. Procollagen C-Proteinase Enhancer 1 (PCPE-1) is an extracellular matrix glycoprotein that has been shown to increase collagen production by enhancing the activity of Procollagen C-Proteinase (PCP) involved in collagen fibrillogenesis and contribute to the fibrotic process. This study investigates the relationship between PCPE-1 and renal function in myeloma patients.

METHODS

Eighty-one adults, consisting of 61 patients diagnosed with MM and 20 healthy controls, were included in this cross-sectional study. The MM patients with renal injury (RI) were classified as "MM-RI( +)" and those with no RI as "MM-RI(-)".

RESULTS

The median serum PCPE-1 level was 10.7 (5.0-39.4) ng/mL for the entire study population, 9.9 (5.0-13.6) ng/mL for the control group, 10.0 (6.4-22.5) ng/mL for the MM-RI(-) group, and 11.4 (8.1-39.4) ng/mL for the MM-RI( +) group. The difference between the control group and MM-RI( +) group was statistically significant (p < 0.013). PCPE-1 levels negatively correlated with estimated glomerular filtration rate (eGFR), serum albumin, and hemoglobin levels but positively correlated with serum creatinine and CRP levels in the entire study population. Among MM patients, only serum phosphorus and beta-2-microglobulin (β2M) were positively correlated with PCPE-1. PCPE-1 levels was not affected by other parameters in the entire study population and in the MM group.

CONCLUSIONS

Although serum PCPE-1 was higher in the MM-RI( +) group, it was thought to be associated with low GFR reflecting non-specific kidney injury rather than myeloma-related kidney injury.

Procollagen C-proteinase enhancer-1 (PCPE-1), a potential biomarker and therapeutic target for fibrosis

The correct balance between collagen synthesis and degradation is essential for almost every aspect of life, from development to healthy aging, reproduction and wound healing. When this balance is compromised by external or internal stress signals, it very often leads to disease as is the case in fibrotic conditions. Fibrosis occurs in the context of defective tissue repair and is characterized by the excessive, aberrant and debilitating deposition of fibril-forming collagens. Therefore, the numerous proteins involved in the biosynthesis of fibrillar collagens represent a potential and still underexploited source of therapeutic targets to prevent fibrosis. One such target is procollagen C-proteinase enhancer-1 (PCPE-1) which has the unique ability to accelerate procollagen maturation by BMP-1/tolloid-like proteinases (BTPs) and contributes to trigger collagen fibrillogenesis, without interfering with other BTP functions or the activities of other extracellular metalloproteinases. This role is achieved through a fine-tuned mechanism of action that is close to being elucidated and offers promising perspectives for drug design. Finally, the in vivo data accumulated in recent years also confirm that PCPE-1 overexpression is a general feature and early marker of fibrosis. In this review, we describe the results which presently support the driving role of PCPE-1 in fibrosis and discuss the questions that remain to be solved to validate its use as a biomarker or therapeutic target.

Up-regulation of PCOLCE by TWIST1 promotes metastasis in Osteosarcoma

Procollagen C-proteinase enhancer protein (PCOLCE) was originally identified as an enhancer to facilitate the catalysis of procollagens by BMP1. PCOLCE participates in the reconstitution of extracellular and corneal repair. The elevation of PCOLCE in blood indicates that breast cancer has metastasized into the bones. However, direct research on PCOLCE has not been reported.

Methods: ECM candidates were identified by RNA-seq analysis from 4 normal and 16 osteosarcoma tissues. The in vitro migration and invasion abilities of osteosarcoma cells were determined by a Transwell assay. A spontaneous metastatic osteosarcoma model was established to assess osteosarcoma metastasis in vivo. The N-linked glycosylated amino acids were identified by PNGase F treatment combined with Western blotting. The mechanism of TWIST1 regulating PCOLCE transcription was elucidated by luciferase, qPCR and ChIP assays.

Results: PCOLCE was markedly up-regulated in human osteosarcoma tissues compared to its expression in noncancerous adjacent tissues; high PCOLCE expression in tissues correlated with a poor patient prognosis, and the knockdown of PCOLCE by shRNAs impaired the migration, invasion and lung metastasis of osteosarcoma cells. The overexpression of wild-type PCOLCE, but not its N29Q mutant, promoted migration, invasion and metastasis, indicating that the glycosylation of PCOLCE at Asn29 is necessary for its functions in osteosarcoma. TWIST1, a key transcription factor in metastasis, was also overexpressed in osteosarcoma tissues and positively correlated with either PCOLCE or its potential procollagen substrates, such as COL1A1, COL1A2, COL5A1, COL8A2 and COL10A1.

Conclusion: Our findings are the first to provide evidence that PCOLCE plays a critical role in promoting the lung metastasis of osteosarcoma, and this up-regulation of PCOLCE by TWIST1 may lead to a new therapeutic strategy to treat patients with metastatic osteosarcoma.

Procollagen C-Proteinase Enhancer 1 (PCPE-1) in Liver Fibrosis

Fibrosis is characterized by excessive deposition of collagen and additional extracellular matrix (ECM) components in response to chronic injuries. Liver fibrosis often results from chronic hepatitis C virus infection and alcohol abuse that can deteriorate to cirrhosis and liver failure. Current noninvasive diagnostic methods of liver fibrosis are limited in their ability to detect and differentiate between early and intermediate stages of fibrosis. New biomarkers of fibrosis that reflect ECM turnover are therefore badly needed. Procollagen C-proteinase enhancer 1 (PCPE-1), a connective tissue glycoprotein that functions as a positive regulator of C-terminal procollagen processing and subsequent collagen fibril assembly, is a promising candidate. Its tissue distribution and expression profile overlap those of collagen, and its expression in fibrosis is upregulated in parallel to the increase in collagen expression. The potential of PCPE-1 as a biomarker of liver fibrosis was recently established using a CCl₄ mouse model of liver fibrosis by showing that the increase in collagen and PCPE-1 content in the fibrotic mouse liver was reflected by elevated plasma levels of PCPE-1. This was achieved using a newly developed highly sensitive, specific, accurate, and reproducible ELISA for mouse PCPE-1, which is based on commercially available antibodies and is offered as a new research tool in the field. A similar ELISA test was developed for human PCPE-1, and preliminary results with plasma from liver fibrosis patients revealed increased plasma concentrations of PCPE-1 in some patients. The protocols of both ELISA tests are outlined herein in great detail to permit their application by any laboratory with similar interests.

Breast cancer cells obtain an osteomimetic feature via epithelial-mesenchymal transition that have undergone BMP2/RUNX2 signaling pathway induction

Bone is one of the most common organs of breast cancer metastasis. Cancer cells that mimic osteoblasts by expressing bone matrix proteins and factors have a higher likelihood of metastasizing to bone. However, the molecular mechanisms of osteomimicry formation of cancer cells remain undefined. Herein, we identified a set of bone-related genes (BRGs) that are ectopically co-expressed in primary breast cancer tissues and determined that osteomimetic feature is obtained due to the osteoblast-like transformation of epithelial breast cancer cells that have undergone epithelial-mesenchymal transition (EMT) followed by bone morphogenetic protein-2 (BMP2) stimulation. Furthermore, we demonstrated that breast cancer cells that transformed into osteoblast-like cells with high expression of BRGs showed enhanced chemotaxis, adhesion, proliferation and multidrug resistance in an osteoblast-mimic bone microenvironment in vitro. During these processes, runt-related transcription factor 2 (RUNX2) functioned as a master mediator by suppressing or activating the transcription of BRGs that underlie the dynamic antagonism between the TGF-β/SMAD and BMP/SMAD signaling pathways in breast cancer cells. Our findings suggest a novel mechanism of osteomimicry formation that arises in primary breast tumors, which may explain the propensity of breast cancer to metastasize to the skeleton and contribute to potential strategies for predicting and targeting breast cancer bone metastasis and multidrug resistance.

Procollagen C-Proteinase Enhancer 1 (PCPE-1) as a Plasma Marker of Muscle and Liver Fibrosis in Mice

Current non-invasive diagnostic methods of fibrosis are limited in their ability to identify early and intermediate stages of fibrosis and assess the efficacy of therapy. New biomarkers of fibrosis are therefore constantly sought for, leading us to evaluate procollagen C-proteinase enhancer 1 (PCPE-1), a fibrosis-related extracellular matrix glycoprotein, as a plasma marker of fibrosis. A sandwich ELISA that permitted accurate measurements of PCPE-1 concentrations in mouse plasma was established. Tissue fibrosis was assessed using histochemical, immunofluorescence, and immunoblotting analyses for type I collagen and PCPE-1. The normal plasma concentration of PCPE-1 in 6 weeks to 4 months old mice was ~200 ng/ml (189.5 ± 11.3 to 206.8 ± 13.8 ng/ml). PCPE-1 plasma concentrations in four and 8.5 months old mdx mice displaying fibrotic diaphragms increased 27 and 40% respectively relatively to age-matched control mice, an increase comparable to that of the N-propeptide of procollagen type III (PIIINP), a known blood marker of fibrosis. PCPE-1 plasma levels in mice with CCl4-induced liver fibrosis increased 34 to 50% relatively to respective controls and reflected the severity of the disease, namely increased gradually during the progression of fibrosis and went down to basal levels during recovery, in parallel to changes in the liver content of collagen I and PCPE-1. The results favor PCPE-1 as a potential new clinically valuable fibrosis biomarker.

Metalloproteinases in Drosophila to humans that are central players in developmental processes

Many secreted proteins are synthesized as precursors with propeptides that must be cleaved to yield the mature functional form of the molecule. In addition, various growth factors occur in extracellular latent complexes with protein antagonists and are activated upon cleavage of such antagonists. Research in the separate fields of embryonic patterning and extracellular matrix formation has identified members of the BMP1/Tolloid-like family of metalloproteinases as key players in these types of biosynthetic processing events in species ranging from Drosophila to humans.

The proteome and gene expression profile of cementoblastic cells treated by bone morphogenetic protein-7 in vitro

AIM

Regenerative periodontal therapy is often unpredictable and limited. Cementum regeneration is necessary for the proper repair of a periodontal ligament. The precise mechanism how bone morphogenetic protein-7 (BMP7) induces differentiation and mineralization of cementoblasts remains undetermined. The purpose of this study was to evaluate the effect of BMP7 on early proteome and gene expression profile of cementoblastic OCCM.30 cells in vitro.

MATERIALS AND METHODS

Immortalized murine cementoblasts (OCCM.30) were exposed to BMP7 and evaluated for: (1) proliferation; (2) mineralization; (3) early proteome profile using liquid chromatography-mass spectrometry (LC-MS); and (4) gene expression by quantitative RT-PCR.

RESULTS

Bone morphogenetic protein-7 increased the cell proliferation at 24 h and 48 h, while higher doses suppressed the cell proliferation at 48 h. BMP7 induced the mineralization of cementoblasts following 8 days of therapy. Using LC-MS we identified 1117 proteins from the cell lysate. Many belonged to extracellular matrix formation such as PCPE1, collagens, annexins and integrin receptors. RT-PCR analyses revealed a BMP7 dose-dependent upregulation of BMP1, TGFβ1, osterix, osteoprotegerin, procollagen I and II, PCPE1, and noggin, while BMP6 and chordin expression were decreased. The high BMP7 dose down regulated most of the genes 24 h following therapy.

CONCLUSION

Bone morphogenetic protein-7 promotes differentiation and mineralization of cementoblasts via inducing PCPE1 and BMP1 responsible for processing of type I collagen.

Quantification of human serum procollagen C-proteinase enhancer (hsPCPE) glycopattern

BACKGROUND

Procollagen C-proteinase enhancer 1 (PCPE1), a glycoprotein secreted from differentiating osteoblast, enhances the rate-limiting step of collagen type I fibrillar formation. It is expressed and secreted by cells that produce collagen type I and has the potential to be a marker for bone pathologies.

METHODS

We developed an assay to quantify PCPE glycopattern based on isoelectric focusing (IEF) and detection with a bio-imaging camera (coefficient of variation within and between assays, 15% and 20%, respectively).

RESULTS

PCPE was quantified in 39 serum samples from healthy subjects (17 females and 22 males). The concentration in the serum was 305(274) ng/ml, median(IQR). The level of the PCPE isoforms and their relative distribution were altered in patients with bone disorders.

CONCLUSIONS

The data generated by our system, support our hypothesis that combined data on PCPE concentration and isoforms may be useful for the diagnosis and follow-up of bone diseases. Further research, on larger cohorts of both normal subjects and patients, must be done.