Equine sarcoids: Bovine Papillomavirus type 1 transformed fibroblasts are sensitive to cisplatin and UVB induced apoptosis and show aberrant expression of p53

Expression of Cell-Cycle Regulatory Proteins pRb, Cyclin D1, and p53 Is Not Associated with Recurrence Rates of Equine Sarcoids

Sarcoids are among the most common tumors diagnosed in equids; their association with bovine papillomaviruses (BPV) infection has been widely reported, but the mechanism of carcinogenesis has not been fully elucidated. To verify whether BPV infection causes dysregulation of the pRb-Cyclin D1-p16CDKN2A-p53 pathway as reported for human papillomavirus (HPV), the study employed immunohistochemistry to test 55 equine sarcoid biopsies for the expression of pRb, Cyclin D1, and p53 cell cycle regulatory proteins and to evaluate the proliferative rate through Ki67. High Cyclin D1 and pRb expression were observed in 51% and 80% of cases, respectively, while low expression was observed in 49% and 20% of cases, respectively. Significantly higher Ki67 proliferation indexes were observed in fibroblastic, nodular, and mixed sarcoids compared to the occult and verrucous. High proliferation was significantly associated with high Cyclin D1 expression. In contrast with previous studies, p53 positivity was not observed in the cases examined in this study. Moreover, follow-up analysis revealed that fibroblastic, mixed sarcoids were associated with significantly higher local recurrence rates while the verrucous subtype was associated with higher rates of new sarcoid development at distant sites.

Equine Sarcoids-Causes, Molecular Changes, and Clinicopathologic Features: A Review

Equine sarcoid is the most common skin tumor of horses. Clinically, it occurs as a locally invasive, fibroblastic, wart-like lesion of equine skin, which has 6 clinical classes: occult, verrucose, nodular, fibroblastic, mixed, and malignant. Sarcoids may be single but multiple lesions are more frequent. The typical histological feature is increased density of dermal fibroblasts which form interlacing bundles and whorls within the dermis. Lesions are mostly persistent, resist therapy, and tend to recur following treatment. In general, sarcoids are not fatal but their location, size, and progression to the more aggressive form may lead to the withdrawal of a horse from use and serious infringement of their welfare leading to the loss of valuable animals. Bovine papillomavirus (BPV) type 1 and less commonly type 2 contribute to the development of equine sarcoid. The viral genome and proteins are detected in a high percentage of cases. Furthermore, viral oncoprotein activity leads to changes in the fibroblastic tissue similar to changes seen in other types of tumors. Equine sarcoids are characterized by a loss of tumor suppressor activity and changes allowing abnormal formation of the affected tissue, as well as y immune defense abnormalities that weaken the host's immune response. This impaired immune response to BPV infection appears to be crucial for the development of lesions that do not spontaneously regress, as occurs in BPV-infected cows.

Molecular approaches to equine sarcoids

Sarcoids are the most commonly diagnosed skin tumours in equines. Bovine papillomaviruses (BPVs) are the primary causative agent of sarcoids. There has been intensive research to discover the molecular mechanisms that may contribute to the aetiopathogenesis of this disease and tumour suppressors and proto-oncogenes known to play a role in human neoplastic conditions have been investigated in equine sarcoids. Current approaches include the identification of gene expression profiles, characterising sarcoid and normal skin tissues, and an assessment of epigenetic alterations such as microRNA differential expression and DNA methylation status. This review focuses on selected groups of genes that contribute to the molecular mechanisms of sarcoid formation. These genes have the potential to complement current clinical examinations of equine sarcoid disease in diagnosis, prognosis, therapeutic response and screening.

Clinico-Histopathological and Immunohistochemical Study of Ruminant's Cutaneous Papillomavirus in Iraq

The papilloma viruses are constituted of double-stranded DNA and are a more common lesion in ruminant's skin in Iraq. The p53 tumor suppressor protein reveals an essential role in cell cycle control. This study intends to investigate the clinical, histopathological, and immunohistochemical features of cutaneous papilloma in ruminants in Iraq. Samples had been collected from a total of 10 animals (three cattle, three goats, and four sheep) with multiple papillomatosis lesions. The samples were processed for histopathological and immunohistochemical techniques. Clinically, the lesions appeared as multiple various sizes (0.5–11 cm), cauliflower exophytic masses on different parts of the animal's body. The histopathological features of the epidermis granular layer revealed perinuclear vacuolation (koilocytosis) accompanied by various degrees of hypergranulosis, hyperkeratosis, acanthosis, orthokeratosis, and parakeratosis. Strong positive reaction for papillomavirus antigen was seen in both epidermal basal and granular layers in the immunohistochemical investigation (IHC). Moreover, all papilloma lesions revealed an intense positive p53 reaction in cytoplasmic and perinuclear of the basal and parabasal layers. In conclusion, this study described the papillomavirus lesions in bovine, ovine, and caprine animals, which were found in different parts areas of the affected animals. All lesions show similar histopathological features with minor variations. PV antigen and p53 protein expression showed positive results in immunohistochemistry that can be used as diagnostic markers for ruminant's papilloma.

Oral sarcoid in a cat

A 10-month-old, domestic shorthaired, spayed female cat was presented to the Veterinary Medical Centre, Western College of Veterinary Medicine, for evaluation of an oral mucosal mass. Histopathology and polymerase chain reaction with sequencing allowed for a definitive diagnosis of bovine papillomavirus type-14-associated oral sarcoid. The mass resolved spontaneously following incisional biopsy and was still grossly absent 10 months later.

Comparative transcriptomic analysis of bovine papillomatosis

BACKGROUND

Bovine papillomavirus (BPV) belongs to the Papillomaviridae family and infects epithelial cells of bovines and closely related animals, causing hyperproliferative lesions known as warts or papillomas, which may regress or progress to form benign or malignant tumors. The virus enters the host cell and interacts with it by altering the regulation of genes that are responsible for controlling the cell cycle, thus triggering lesion formation. It is not yet known which host genes are regulated by viral infection. Therefore, the objective of this study was to make use of next-generation RNA sequencing methods to identify differentially expressed genes associated with BPV infection, which might elucidate possible marker genes that could be used to control the disease.

RESULTS

Transcriptome analysis revealed that 1343 genes were differentially regulated (FDR < 0.05). A comparison of gene expression in infected and noninfected cows indicated that 655 genes were significantly upregulated, and 688 genes were significantly downregulated. Most differentially expressed genes were associated with BPV infection pathways, which supports the hypothesis that viral infection was the mechanism associated with this regulation.

CONCLUSIONS

This is the first study that focused on a large-scale evaluation of gene expression associated with BPV infection, which is important to identify possible metabolic pathways regulated by host genes for lesion development. In addition, novel targets could be identified in order to find ligands that interact with BPV, with the aim of interrupting the infection cycle.

Malignant transformation of canine oral papillomavirus (CPV1)-associated papillomas in dogs: An emerging concern?

Canine oral papillomavirus (CPV1, also known as COPV), the most common cause of non-neoplastic papillomas, has not been shown to cause squamous cell carcinomas (SCC). Furthermore, malignant transformation of benign papillomas to SCC has only been reported in a single group of dogs with severe combined immunodeficiency infected with CPV2. Here, we report a series of 7 dogs with benign CPV1-associated papillomas with histologic evidence of CPV1 causing malignant transformation to carcinoma in situ and ultimately SCC. Expression of p53 and p16 proteins in CPV1-infected cells within the benign papillomas and lesions that progressed into SCC also supported an association between papillomavirus and malignant transformation. Moreover, our retrospective analysis indicated that while there have been increased numbers of viral papillomas with malignant transformation, the number of annually diagnosed canine viral papillomas has remained constant over the past decade in our laboratory. We speculate that either an altered host immunity from increased usage of immunosuppressive drugs or changing environmental factors, e.g. increase exposure to UV radiation, may cause an increased oncogenic potential of this “low-risk” virus. This study aims to raise awareness of the malignant potential of CPV1 and to encourage further investigations into the cause of this suspected change in its oncogenic potential.

Ocular squamous cell carcinoma in Holstein cows from the South of Brazil

Aim

The aim of this study was to investigate 10 cases of bovine ocular squamous cell carcinoma (OSCC) diagnosed in Holstein or Holstein-crosses cows.

Materials and Methods

The investigation was performed exclusively in OSCC cases diagnosed in the State of Paraná and Santa Catarina. A combination of two previously existing histopathological classifications systems was used. The tissue samples were tested for immunoexpression of p53 and p16 and polymerase chain reaction (PCR) for bovine herpesvirus and papillomavirus.

Results

A positive correlation between number of mitotic figures and tissue invasion was found. Anaplasia parameters did not correlate well with tumor invasion of deeper tissues and mitotic counts. Six of 10 OSCC cases were in animals with heavily pigmented eyes. Immunoexpression of p53 and p16 was observed in 3 cases each. Bovine herpesvirus and papillomavirus were not detected by PCR.

Conclusions

Our results indicate that OSCC occurrence is most likely multifactorial with genetic, phenotypic, and environmental influences contributing to the pathogenesis of the disease.

Expression of bcl-2 and p53 in bovine cutaneous fibropapillomas

BACKGROUND

Bovine cutaneous fibropapillomas are benign hyperproliferative lesions induced by Bovine Papillomaviruses (BPVs). Bcl-2 is an important anti-apoptotic protein which is expressed in several cancer types. In contrary, p53 is a tumour suppressor protein that mediates cell cycle arrest, apoptosis and senescence in response to cellular stresses.

FINDINGS

Here, we investigated immunohistochemically and biochemically, the expression of bcl-2 and p53 in a subset of BPV positive fibropapillomas and bovine normal skin. Normal skin samples showed a weak signal for both proteins in the cytoplasm of the basal cells. Nine out of twelve (75%) tumour samples stained positive for bcl-2 throughout basal and parabasal layers, with most of cells showing strong cytoplasmic immunoreactivity. Nine out of twelve (75%) fibropapillomas were found to be positive for p53 expression, showing a strong cytoplasmic and perinuclear staining of p53 protein mainly in the basal and parabasal layers.

CONCLUSIONS

Our data reveal an altered bcl-2 and p53 immunoreactivity in bovine cutaneous fibropapillomas, suggesting involvement of these two proteins in the cutaneous neoplastic transformation through an impaired apoptotic process.

BAG3 protects bovine papillomavirus type 1-transformed equine fibroblasts against pro-death signals

In human cancer cells, BAG3 protein is known to sustain cell survival. Here, for the first time, we demonstrate the expression of BAG3 protein both in equine sarcoids in vivo and in EqS04b cells, a sarcoid-derived fully transformed cell line harbouring bovine papilloma virus (BPV)-1 genome. Evidence of a possible involvement of BAG3 in equine sarcoid carcinogenesis was obtained by immunohistochemistry analysis of tumour samples. We found that most tumour samples stained positive for BAG3, even though to a different grade, while normal dermal fibroblasts from healthy horses displayed very weak staining pattern for BAG3 expression. By siRNA technology, we demonstrate in EqS04b the role of BAG3 in counteracting basal as well as chemical-triggered pro-death signals. BAG3 down-modulation was indeed shown to promote cell death and cell cycle arrest in G₀/G₁. In addition, we found that BAG3 silencing sensitized EqS04b cells to phenethylisothiocyanate (PEITC), a promising cancer chemopreventive/chemotherapeutic agent present in edible cruciferous vegetables. Notably, such a pro-survival role of BAG3 was less marked in E. Derm cells, an equine BPV-negative fibroblast cell line taken as a normal counterpart. Altogether our findings might suggest a mutual cooperation between BAG3 and viral oncoproteins to sustain cell survival.