Expression of cell cycle associated proteins cyclin A, CDK-2, p27kip1 and p53 in equine sarcoids

Nicolson

Marchetti

et al. 2008

J Virol

Bovine papillomavirus type 1 (BPV-1) and, less commonly, BPV-2 are associated with the pathogenesis of common equine skin tumors termed sarcoids. In an attempt to understand the mechanisms by which BPV-1 induces sarcoids, we used gene expression profiling as a screening tool to identify candidate genes implicated in disease pathogenesis. Gene expression profiles of equine fibroblasts transformed by BPV-1 experimentally or from explanted tumors were compared with those of control equine fibroblasts to identify genes associated with expression of BPV-1. Analysis of the microarray data identified 81 probe sets that were significantly (P < 0.01) differentially expressed between the BPV-1-transformed and control cell lines. Expression of several deregulated genes, including MMP-1, CXCL5, FRA-1, NKG7, TLR4, and the gene encoding the major histocompatibility complex class I (MHC-I) protein, was confirmed using other BPV-1-transformed cell lines. Furthermore, expression of these genes was examined using a panel of 10 sarcoids. Increased expression of MMP-1, CXCL5, FRA-1, and NKG7 was detected in a subset of tumors, and TLR4 and MHC I showed robust down-regulation in all tumors. Deregulated expression was confirmed at the protein level for MMP-1 and MHC-I. The present report identifies genes modulated by BPV-1 transformation and will help identify the molecular mechanisms involved in disease pathogenesis.

“…Up-regulation of c-IAP-1 would abrogate apoptotic responses in sarcoids. Interestingly, p53 is disabled in sarcoids and sarcoid cells (10,49,69).…”

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 88%

Transcriptional Changes Induced by Bovine Papillomavirus Type 1 in Equine Fibroblasts

Nicolson

Marchetti

et al. 2008

J Virol

“…Bovine papillomavirus type 1 (BPV-1) and less commonly BPV-2 are the main causes of equine sarcoids. The viral genome is frequently detected in the tumours (Ashrafi et al, 2008; Martens et al, 2001a, b;Nixon et al, 2005;Otten et al, 1993) and the viral proteins are expressed (Borzacchiello et al, 2008;Carr et al, 2001;Nixon et al, 2005).Tumour cell invasion involves degradation of both basement membranes and stromal extracellular matrix by proteinases including matrix metalloproteinases (MMPs) (Birkedal-Hansen, 1995). In the past decades, MMPs have been demonstrated to play a crucial role in initiating degradation of basement membrane and extracellular matrix to allow tumour cell invasion (Westermarck & Kähäri, 1999).…”

mentioning

confidence: 99%

Upregulation of equine matrix metalloproteinase 1 by bovine papillomavirus type 1 is through the transcription factor activator protein-1

Journal of General Virology

Gault

Campo

et al. 2011

Self Cite

Equine sarcoids represent the most common skin tumours in equids worldwide, characterized by extensive invasion and infiltration of lymphatics, rare regression and high recurrence after surgical intervention. Bovine papillomavirus type 1 (BPV-1) activity is necessary for the transformation phenotype of equine fibroblasts. Among the many changes induced by BPV-1, matrix metalloproteinase 1 (MMP-1) upregulation contributes to the invasiveness of equine fibroblasts. However, it is not yet known how BPV-1 proteins regulate equine MMP-1 expression. To elucidate this mechanism, the equine MMP-1 promoter was cloned and analysed. A putative activator protein-1 (AP-1)-binding site was demonstrated to be crucial for upregulated MMP-1 promoter activity by BPV-1. BPV-1 E6 and E7 proteins increased MMP-1 promoter activity, and inhibition of BPV-1 gene expression by small interfering RNA significantly reduced the promoter activity. c-Jun and Fra-1, two components of the AP-1 transcription factor complex, were overexpressed and activated by BPV-1 in equine fibroblasts. Finally, BPV-1 E5, E6 and E7 proteins increased MMP-1 mRNA and protein expression. In conclusion, the expression of MMP-1 can be enhanced by BPV-1 oncoproteins E6 and E7 through the AP-1 transcription factor and by E5 via an indirect mechanism. These findings shed light on the mechanism of BPV-1-mediated equine fibroblast infiltration and indicate that both BPV-1 oncoproteins and AP-1 could be potential targets for equine sarcoid therapy. INTRODUCTIONEquine sarcoids are the most common skin tumour in equids worldwide (Jackson, 1936;Pascoe & Summers, 1981;Ragland et al., 1970), with reported prevalence rates ranging from 12.9 to 67 % of all equine tumours (Lavach et al., 1985). They are characterized by extensive localized infiltration and invasion, rare regression and high recurrence (Knottenbelt, 2005;Martens et al., 2001a;Tarwid et al., 1985). Equine sarcoids exhibit six clinical subtypes: occult, verrucose, nodular, fibroblastic, mixed and malevolent (Knottenbelt, 2005). Whilst some lesions may remain quiescent for many years, the milder forms of the disease (occult and verrucose) can undergo transformation to the aggressive fibroblastic type, especially following trauma (Ragland et al., 1970;Tarwid et al., 1985). The high recurrence of equine sarcoids may stem from the high invasiveness of sarcoid fibroblasts (Yuan et al., 2010a). Bovine papillomavirus type 1 (BPV-1) and less commonly BPV-2 are the main causes of equine sarcoids. The viral genome is frequently detected in the tumours (Ashrafi et al., 2008; Martens et al., 2001a, b;Nixon et al., 2005;Otten et al., 1993) and the viral proteins are expressed (Borzacchiello et al., 2008;Carr et al., 2001;Nixon et al., 2005).Tumour cell invasion involves degradation of both basement membranes and stromal extracellular matrix by proteinases including matrix metalloproteinases (MMPs) (Birkedal-Hansen, 1995). In the past decades, MMPs have been demonstrated to play a crucial role in initiating degradation of baseme...

“…Whereas p38 has previously been considered as a mediator of stress-induced apoptosis (Boosani et al, 2009), it is also associated with enhanced cellular proliferation particularly in breast cancer cells with non-functional p53 (Zhao et al, 1999). We have previously demonstrated that in some sarcoids, p53 expression is perinuclear and its function is abrogated in vitro (Nixon et al, 2005;Yuan et al, 2008a). BPV-1 E6 can inhibit the function of p53 by interaction with its co-activator CBP/ p300 (Zimmermann et al, 2000).…”

Section: Discussionmentioning

confidence: 99%

“…Experimental inoculation of equine skin with BPV induces sarcoid-like lesions in horses (Ragland & Spencer, 1969). The viral genome is frequently detected in tumours (Ashrafi et al, 2008; Martens et al, 2001a, b;Nixon et al, 2005;Otten et al, 1993) and its proteins are expressed (Borzacchiello et al, 2008;Carr et al, 2001;Nasir & Reid, 1999;Nixon et al, 2005). It is likely that sarcoidspecific BPV DNA is transmitted between equids by flies (Finlay et al, 2009).…”

mentioning

confidence: 99%

p38 mitogen-activated protein kinase is crucial for bovine papillomavirus type-1 transformation of equine fibroblasts

Journal of General Virology

Gault

Campo

et al. 2011

Self Cite

Equine sarcoids represent the most common skin tumours in equids worldwide, characterized by extensive invasion and infiltration of lymphatics, rare regression and high recurrence after surgical intervention. Bovine papillomavirus type-1 (BPV-1) and less commonly BPV-2 are the causative agents of the diseases. It has been demonstrated that BPV-1 viral gene expression is necessary for maintaining the transformation phenotype. However, the underlying mechanism for BPV-1 transformation remains largely unknown, and the cellular factors involved in transformation are not fully understood. Previously mitogen-activated protein kinase (MAPK) signalling pathway has been shown to be important for cellular transformation. This study investigated the role of p38 MAPK (p38) in the transformation of equine fibroblasts by BPV-1. Elevated expression of phosphorylated p38 was observed in BPV-1 expressing fibroblasts due to the expression of BPV-1 E5 and E6. The phosphorylation of the MK2 kinase, a substrate of p38, was also enhanced. Inhibition of p38 activity by its selective inhibitor SB203580 changed cell morphology, reduced the proliferation of sarcoid fibroblasts and inhibited cellular invasiveness, indicating the indispensable role of p38 in BPV-1 transformation of equine fibroblasts. These findings provide new insights into the pathogenesis of equine sarcoids and suggest that p38 could be a potential target for equine sarcoid therapy. INTRODUCTIONEquine sarcoids are the most common fibroblastic skin tumours in equids worldwide (Jackson, 1936;Pascoe & Summers, 1981;Ragland et al., 1970). These tumours can occur as single or multiple lesions in different clinical types including occult, verrucose, nodular, fibroblastic, mixed and malevolent types (Knottenbelt, 2005). Extensive localized infiltration and invasion, rare regression and high recurrence are characteristic of this type of tumour (Knottenbelt, 2005;Martens et al., 2001a;Tarwid et al., 1985). It is now widely accepted that bovine papillomavirus (BPV) types 1 and 2 are the causative agents of sarcoids. Experimental inoculation of equine skin with BPV induces sarcoid-like lesions in horses (Ragland & Spencer, 1969). The viral genome is frequently detected in tumours (Ashrafi et al., 2008; Martens et al., 2001a, b;Nixon et al., 2005;Otten et al., 1993) and its proteins are expressed (Borzacchiello et al., 2008;Carr et al., 2001;Nasir & Reid, 1999;Nixon et al., 2005). It is likely that sarcoidspecific BPV DNA is transmitted between equids by flies (Finlay et al., 2009). The BPV-1 genome isolated from a sarcoid can transform equine fetal fibroblasts and inhibition of viral gene expression by small interfering RNAs (siRNA) reverts the transformed phenotype of sarcoid fibroblasts (Yuan et al., 2008a(Yuan et al., , 2011.While BPV infection plays a major role in the pathogenesis of sarcoid, numerous cellular factors have been shown to be important for initiation and progression of tumours. The downregulation of major histocompatibility complex type I (MHC I) by BPV-1 E5 and...