Fludarabine induces pro-inflammatory activation of human monocytic cells through a MAPK/ERK pathway

Fludarabine modulates expression of type VII collagen during haematopoietic stem cell transplantation for recessive dystrophic epidermolysis bullosa

BACKGROUND

Recessive dystrophic epidermolysis bullosa (RDEB) is a severe, complicated inherited blistering skin disease with few treatment options currently available. Recently, haematopoietic stem cell transplantation (HCT) has been used as an alternative therapy that can improve skin integrity, but it is not known if the preparative HCT regimen also contributes to the therapeutic response.

OBJECTIVES

To determine whether chemotherapy drugs used in the HCT preparative regimen influence type VII collagen (C7) expression, which is inherently reduced or absent in RDEB skin, and to explore the pathomechanisms of such responses, if present.

METHODS

Drugs from the HCT preparative regimen (busulfan, cyclophosphamide, ciclosporin A, fludarabine and mycophenolate) with inhibitors (PD98059, U0126, LY294002, SR11302, SIS3 and N-acetyl-l-cysteine) were added to normal human dermal and human RDEB fibroblasts. C7 expression was measured using reversetranscription polymerase chain reaction and immunoblotting.

RESULTS

We uncovered a previously unknown consequence of fludarabine whereby dermal fibroblasts exposed to fludarabine upregulate C7. This effect is mediated, in part, through activation of the mitogen-activated protein kinase/extracellular signal-regulated kinase, phosphoinositide 3-kinase/protein kinase B and transforming growth factor-β pathways. Activation of these pathways leads to activation of downstream transcription factors, including activator protein 1 (AP-1) and SMAD. Subsequently, both AP-1 and SMAD bind the COL7A1 promoter and increase COL7A1 expression.

CONCLUSIONS

Fludarabine influences the production of type VII collagen in RDEB fibroblasts.

Pentraxin 3 plasma levels at graft-versus-host disease onset predict disease severity and response to therapy in children given haematopoietic stem cell transplantation

Acute Graft-versus-Host Disease (GvHD) remains a major complication of allogeneic haematopoietic stem cell transplantation, with a significant proportion of patients failing to respond to first-line systemic corticosteroids. Reliable biomarkers predicting disease severity and response to treatment are warranted to improve its management. Thus, we sought to determine whether pentraxin 3 (PTX3), an acute-phase protein produced locally at the site of inflammation, could represent a novel acute GvHD biomarker. Using a murine model of the disease, we found increased PTX3 plasma levels after irradiation and at GvHD onset. Similarly, plasma PTX3 was enhanced in 115 pediatric patients on day of transplantation, likely due to conditioning, and at GvHD onset in patients experiencing clinical symptoms of the disease. PTX3 was also found increased in skin and colon biopsies from patients with active disease. Furthermore, PTX3 plasma levels at GvHD onset were predictive of disease outcome since they resulted significantly higher in both severe and therapy-unresponsive patients. Multiple injections of rhPTX3 in the murine model of GvHD did not influence the disease course. Taken together, our results indicate that PTX3 constitutes a biomarker of GvHD severity and therapy response useful to tailor treatment intensity according to early risk-stratification of GvHD patients.

2-chloroadenosine modulates PAR-1 and IL-23 expression and enhances docetaxel effects on PC3 cells

BACKGROUND

Docetaxel-based chemotherapy is the only treatment that demonstrated an overall survival benefit in men with hormone refractory prostate cancer. 2-CADO inhibits the growth of PC3 cells by inducing apoptosis and cell cycle arrest through a mechanism that involves cellular uptake.

METHODS

Androgen-independent and -sensitive (PC3 and LNCaP) prostate cancer cells and non-neoplastic HECV cells were used in the study. Proliferation and cell cycle progression were analyzed in the presence of 2-CADO and Docetaxel. Invasive potential was assessed by soft agar assay and metastatic ability by adhesion assay. IL-23 and PAR-1 expression were determined by real time PCR.

RESULTS

2-CADO pre-treatment followed by Docetaxel at subclinical dosage reduced the viability of either PC3 or LNCaP while it did not enhance Docetaxel-induced cytotoxicity in adherent non-neoplastic HECV. The drugs reduced the invasive potential of PC3 cells by inducing apoptosis and blocking cell cycle progression in the S-phase. Down-regulation of PAR-1 gene expression resulted in a slightly lower metastatic potential, whereas up-regulation of IL-23 induced the activation of the immune system.

CONCLUSIONS

Pretreatment of PC3 cells with 2-CADO decreased the effective concentration of Docetaxel, lowered the metastatic potential, and induced the production of cytokines known to stimulate the immune response against cancer. The treatment was effective for prostate cancer cells independently on their androgen sensitiveness.

Mycophenolic Acid Induces Islet Apoptosis by Regulating Mitogen-Activated Protein Kinase Activation

Mycophenolic acid (MPA), an inosine monophosphate dehydrogenase inhibitor, is widely used as an immunosuppressive drug after transplantations including those of pancreas islet cells. However, recent reports have indicated that MPA has apoptotic effects on islet cells in vitro. To study the effect of MPA on islet cells and determine its mechanism, we used an insulin secreting cell-line, HIT-T15. We examined mitogen-activated protein kinase (MAPK) activation after MPA treatment, and determining cell death levels using methylthiazdetetrazolium assays. The activations of extracellular signal-regulated protein kinase (ERK), c-jun N-terminal kinase (JNK), and p38 MAPK and caspase-3 cleavage were measured by Western blotting. MPA (1, 10, 30 micromol/L) increased cell death and caspase-3 cleavage within 24 hours. Exogenous 500 micromol/L guanosine reversed the MPA-induced islet cell death, but exogenous adenosine did not. MPA 10 micromol/L induced cell apoptosis and increased the activations of JNK, ERK, and p38 MAPK. Furthermore, exogenous guanosine, but not exogenous adenosine, reversed these effects induced by MPA. This study demonstrated that MPA may induce islet apoptosis in HIT-T15 cells by increasing activations of JNK, ERK, and p38 MAPK in a guanosine-dependent manner.