The novel AKT inhibitor afuresertib suppresses human Merkel cell carcinoma MKL-1 cell growth.

Merkel cell carcinoma (MCC) is a highly aggressive neuroendocrine neoplasm of the skin, which has an exceedingly poor prognosis. The AKT/mammalian target of rapamycin (mTOR) signalling pathway, which plays a pivotal role in the modulation of protein synthesis and cell survival, has been shown to be extremely important for Merkel cell carcinogenesis. In the current study, we found that AKT has important regulatory functions in MCC cells and that inhibition of AKT with the novel ATP-competitive AKT inhibitor, afuresertib, has widespread effects on proliferative pathways. In particular, we found that treatment of MCC cells with afuresertib led to deactivation of mTOR and glycogen synthase kinase 3 pathway proteins while increasing activation of proapoptotic pathways through the upregulation of p16 expression and phosphomodulation of the B-cell lymphoma-2-associated death promoter. Overall, afuresertib treatment led to significant and robust inhibition of MCC cell proliferation, thus raising intriguing questions regarding the potential efficacy of AKT inhibition for the future clinical management of MCC.

Polyomaviruses of the skin: integrating molecular and clinical advances in an emerging class of viruses.

BACKGROUND: Human polyomaviruses (HPyVs) are small, nonenveloped, double-stranded DNA viruses that express tumour antigen proteins. Fourteen species of polyomaviruses have been discovered in humans, and since the 2008 discovery of the first cutaneous polyomavirus - Merkel cell polyomavirus (MCPyV) - six more species have been detected in the skin: trichodysplasia spinulosa-associated polyomavirus (TSPyV), HPyV6, HPyV7, HPyV9, HPyV10 and HPyV13. Of these cutaneous species, only MCPyV, TSPyV, HPyV6 and HPyV7 have been definitively associated with diseases of the skin, most commonly in immunocompromised individuals. MCPyV is a predominant aetiology in Merkel cell carcinomas. TSPyV is one of the aetiological factors of trichodysplasia spinulosa. HPyV6 and HPyV7 have been recently linked to pruritic skin eruptions. The roles of HPyV9, HPyV10 and HPyV13 in pathogenesis, if any, are still unknown, but their molecular features have provided some insight into their functional biology. RESULTS: In this review, we summarize the known molecular mechanisms, clinical presentation and targeted therapies of each of the eight cutaneous HPyVs. CONCLUSIONS: We hope that heightened awareness and clinical recognition of HPyVs will lead to increased reports of HPyV-associated diseases and, consequently, a more robust understanding of how to diagnose and treat these conditions.

Novel TMC8 splice site mutation in epidermodysplasia verruciformis and review of HPV infections in patients with the disease.

BACKGROUND: Epidermodysplasia verruciformis (EV) is a genodermatosis leading to infections with cutaneous HPV, persistent plane warts and a high rate of non-melanoma skin cancer (NMSC). Biallelic loss-of-function mutations in TMC6 and TMC8 are known to be causative. OBJECTIVE: The aim of this study was to report EV-causing mutations in four patients with EV and to give an overview of all described patients with EV. PATIENTS AND METHODS: We investigated four patients with classical features of EV from two families. All patients were affected by plane warts with typical EV histology since early childhood, and ß-HPVs were detected on their skin. One patient had recurring cutaneous squamous cell carcinomas (cSCC) and carcinomas in situ (Bowen type). We sequenced both TMC6/8 for disease-causing mutations and quantified levels of gene expression. We also performed a systematic literature review to discuss these patients in the context of previously reported cases, mutations already identified, as well as HPV types. RESULTS: Three patients of one family carried a homozygous splice site mutation in TMC8 resulting in aberrantly spliced transcripts that were not degraded. By contrast, no TMC6/8 mutation was detected in the patient from the other family. A systematic literature review revealed 501 described patients with EV. Around 40% of patients with EV analysed for genetic alterations carried no mutation in TMC6/8. While ß-HPVs were identified in the majority of cases, α-HPVs were detected in several individuals. CONCLUSION: The relatively high proportion of EV patients without mutation in TMC6/8 indicates the existence of EV-causing mutations in additional, presently unknown gene(s). However, a homozygous TMC8 splice site mutation in our patients resulted in aberrant transcripts which cannot retain the healthy phenotype. The literature review revealed that HPV-5 is the most commonly identified HPV in patients with EV, but HPV-3, HPV-14 and HPV-20 were unexpectedly identified more frequently than HPV-8.

Dysregulation of the MEK/ERK/MNK1 signalling cascade by middle T antigen of the trichoydsplasia spinulosa polyomavirus.

BACKGROUND: Trichodysplasia spinulosa (TS) is a disfiguring folliculocentric cutaneous disease caused by infection with the trichodysplasia spinulosa polyomavirus (TSPyV). The TSPyV genome contains splice variants encoding the middle tumour (mT) antigen, although the potential role for TSPyV mT antigen in disease development remains unknown. OBJECTIVE: The current study was designed to investigate the mechanistic properties of TSPyV mT antigen, which may further our understanding of TS pathogenesis and provide insight into potential therapies. METHODS: A lentiviral packaging system was used to create an inducible cell line expressing TSPyV mT antigen. Proteins were extracted, separated by SDS-PAGE and subjected to Western blot analysis. Co-immunoprecipitation experiments and mutational analyses were also performed to evaluate protein-protein interactions of mT antigen. RESULTS: We describe a novel mechanism of action for mT antigen that involves hyperactivation of MEK, ERK and MNK1. Our findings suggest that dysregulation of these key signalling molecules depends upon TSPyV mT antigen interaction with protein phosphatase 2A (PP2A) via intact Zn binding motifs. CONCLUSION: Given that PP2A interaction and MEK/ERK/MNK1 phosphorylation are associated with high levels of cell proliferation and inflammation, our findings provide new evidence that TSPyV mT antigen may contribute to the pro-proliferative conditions that lead to TS development.

BRAF inhibitor-associated cutaneous squamous cell carcinoma: new mechanistic insight, emerging evidence for viral involvement and perspectives on clinical management.

Mutations in the BRAF proto-oncogene occur in the majority of cutaneous melanomas. The commonly detected valine (V) to glutamate (E) mutation (V600E) is known to drive melanomagenesis and has thus been the target of two highly selective chemotherapeutic agents: vemurafenib and dabrafenib. While BRAF inhibitor therapy has revolutionized the treatment of metastatic melanoma, unanticipated cutaneous toxicities, including the development of cutaneous squamous cell carcinomas (cSCCs), are frequently reported and hinder therapeutic durability. However, the mechanisms by which BRAF inhibitors induce cutaneous neoplasms are poorly understood, thus posing a challenge for specific therapies. In this review, we summarize the clinical and molecular profiles of BRAF inhibitor-associated cSCCs, with a focus on factors that may contribute to disease pathogenesis. In particular, we discuss the emerging evidence pointing towards viral involvement in BRAF inhibitor-induced cutaneous neoplasms and offer new perspectives on future therapeutic interventions. Continued clinical and mechanistic studies along this line will not only allow for better understanding of the pathogenic progression of BRAF inhibitor-induced cSCCs, but will also lead to development of new therapeutic and preventative options for patients receiving targeted cancer therapy.

Molecular insight into the viral biology and clinical features of trichodysplasia spinulosa.

Trichodysplasia spinulosa (TS) is a disfiguring skin disease that occurs most frequently in patients receiving immunosuppressive therapies, and is thus frequently associated with organ transplantation. TS is characterized clinically by folliculocentric papular eruption, keratin spine formation and development of leonine face; and histologically by expansion of the inner root sheath epithelium and high expression of the proliferative marker Ki-67. Recent discovery of the TS-associated polyomavirus (TSPyV) and emerging studies demonstrating the role of TSPyV tumour antigens in cell proliferation pathways have opened a new corridor for research on TS. In this brief review, we summarize the clinical and histological features of TS and evaluate the current options for therapy. Furthermore, we address the viral aetiology of the disease and explore the mechanisms by which TSPyV may influence TS development and progression. As reports of TS continue to rise, clinician recognition of TS, as well as accompanying research on its underlying pathogenesis and therapeutic options, is becoming increasingly important. It is our hope that heightened clinical suspicion for TS will increase rates of diagnosis and will galvanize both molecular and clinical interest in this disease.

Generalized verrucosis in a patient with GATA2 deficiency.

Generalized verrucosis is a characteristic of several genetic and immunodeficiency disorders including epidermodysplasia verruciformis; warts, hypogammaglobulinaemia, infections and myelokathexis (WHIM) syndrome; warts, immunodeficiency, lymphoedema and anogenital dysplasia (WILD) syndrome; severe combined immune deficiency and HIV, among others. In recent years, it has been consistently recognized in patients with GATA2 deficiency, a novel immunodeficiency syndrome characterized by monocytopenia, B-cell and natural killer-cell lymphopenia, and a tendency to develop myeloid leukaemias and disseminated mycobacterial, human papillomavirus (HPV) and opportunistic fungal infections. Mutations in GATA2 cause haploinsufficiency and track in families as an autosomal dominant immunodeficiency. GATA2 is a transcription factor involved in early haematopoietic differentiation and lymphatic and vascular development. We describe a case of generalized verrucosis with HPV type 57 presenting in a young man with GATA2 deficiency. GATA2 deficiency is a novel dominant immunodeficiency that is often recognized later in life and should be considered in the differential diagnosis of patients with generalized verrucosis.

Epidermodysplasia verruciformis in a HIV-positive patient homozygous for the c917A-->T polymorphism in the TMC8/EVER2 gene.

BACKGROUND: Epidermodysplasia verruciformis (EV) is a rare autosomal-recessive disorder characterized by widespread and persistent infection with human papilloma virus (HPV) and a risk of malignant degeneration. Most cases of EV are caused by mutations in the two EV genes, EVER1/TMC6 and EVER2/TMC8. The clinical presentation of EV takes two different forms, which coexist in most cases. Over a period of years, patients develop plane warts and pityriasis versicolor-like lesions. Sixteen cases of EV in HIV-positive patients have been clinically investigated and reported in the literature. However, different inherited susceptibilities towards HPV infection in immunodeficient patients, like HIV-positive patients, have only rarely been addressed. OBSERVATION: We describe a 22-year-old female patient with a congenital HIV infection, who presented with slowly progressing and confluent erythematous papules on her hands and hypopigmented macules on her extremities. The histopathology was typical for EV, and HPV5 was detected by PCR and reverse hybridization. The 44-year-old HIV-positive mother has no typical EV lesions. The patient is homozygous for an A to T single nucleotide polymorphism (SNP) at position 917 of the TMC8/EVER2 gene. The mother of the patient is heterozygous for this SNP. CONCLUSION: These results support the hypothesis that the combination of immunodeficiency and a susceptibility allele may contribute to the differences in occurrence of EV in HIV-positive patients.

Human papillomavirus (HPV) viral load and HPV type in the clinical outcome of HIV-positive patients treated with imiquimod for anogenital warts and anal intraepithelial neoplasia.

OBJECTIVE: To evaluate the efficacy of 5% imiquimod in HIV-positive male patients with anogenital warts or anal intraepithelial neoplasia (AIN), and to elucidate whether human papillomavirus (HPV) type and viral load were important for clinical outcome and recurrences. METHODS: Thirty-seven patients with histologically proven anogenital warts or AIN were enrolled. Topical 5% imiquimod was applied three times per week for more than 8 h overnight for 16 weeks, although patients were allowed to continue therapy for 4 more weeks if they did not have complete clearance of lesions. RESULTS: Mean age was 34 years. The perianal area was the main lesion location. Thirty-three patients had CD4 counts of < 500 cells/mm(3). Eighteen patients had a histopathological diagnosis of AIN-1. Main HPV types detected corresponded to low-risk HPV types. At 20 weeks of therapy, 46% patients achieved total clearance whereas 14 patients had > 50% clearance. Recurrence was observed in 5 of 17 patients who cleared. Clearance was not influenced by patients' CD4 counts, wart location, HIV viral load or HPV viral load. CONCLUSIONS: The assumption that visible perianal warts are benign lesions in HIV-positive patients has to be reevaluated since an important number of such lesions could correspond to low-grade anal disease, which in turn could progress to high-grade anal disease or cancer. In addition, our results in this preliminary study indicate that imiquimod appears to be effective in treating AIN in HIV-positive patients. Further studies are needed to document its utility to prevent high-grade dysplasia and/or anal cancer.

Association between HLA-DQB1 and cervical dysplasia in Vietnamese women.

Host genetic background seems to play a key role in cervical carcinogenesis as only a small subset of women infected with high-risk human papillomaviruses (HPVs) develop cervical cancer. The rate of cervical cancer in Vietnamese women is notably high. To explore the association of human leukocyte antigen (HLA)-DQB1 alleles, HPV infection, and cervical dysplasia in this population, cervical smears were obtained from 101 women attending the obstetrics and gynecology clinic of Da Nang General Hospital in Vietnam. Besides the Papanicolaou test, HPV and HLA-DQB1 genotyping were performed using cervical smear DNA. Additionally, a subset of 30 blood samples was used as the gold standard for HLA genotyping. HLA-DQB1 alleles showed no association with HPV infection status. However, a positive association with cervical dysplasia was found for HLA-DQB1*0302 (P= 0.0229, relative risk (RR) = 4.737) and HLA-DQB1*0601 (P= 0.0370, RR = 4.038), whereas HLA-DQB1*0301 (P= 0.0152, RR = 0.221) was found negatively associated. The low diversity of HLA-DQB1 alleles, wide spectrum of HPV genotypes, and high prevalence of HPV 16 and HPV 18 observed in the study population suggest a permissive/susceptible genetic background that deserves further research. Total concordance of HLA-DQB1 genotyping results between blood and cervical cells confirms the potential value of cervical smears as an effective tool for the development of cervical cancer biomarkers.

Clinical aspects of epidermodysplasia verruciformis.

Thirteen patients with epidermodysplasia verruciformis (EV) were studied over a period of 7 years. EV is a rare genodermatosis characterized by a generalized infection with a specific group of human papilloma virus (HPV) and a propensity for developing skin malignant tumours in 30%-50% of patients. The diagnosis of EV was confirmed by histopathological and immunohistochemical findings. Three of our patients had the benign form of EV, which is characterized by monomorphous lesions and no malignant changes, whereas 10 had the malignant form, which is characterized by polymorphic lesions and development of cutaneous malignant tumours. All EV patients with the malignant form developed multiple skin tumours (77%). They started to appear at age 20, predominantly on the forehead (50%). Most were squamous cell carcinoma, extremely aggressive and invasive, which provoked metastasis and death in two patients.

Malonyl CoA decarboxylase deficiency: C to T transition in intron 2 of the MCD gene.

Malonyl CoA decarboxylase (MCD) is an enzyme involved in the metabolism of fatty acids synthesis. Based on reports of MCD deficiency, this enzyme is particular important in muscle and brain metabolism. Mutations in the MCD gene result in a deficiency of MCD activity, that lead to psychomotor retardation, cardiomyopathy and neonatal death. To date however, only a few patients have been reported with defects in MCD. We report here studies of a patient with MCD deficiency, who presented with hypotonia, cardiomyopathy and psychomotor retardation. DNA sequencing of MCD revealed a homozygous intronic mutation, specifically a -5 C to T transition near the acceptor site for exon 3. RT-PCR amplification of exons 2 and 3 revealed that although mRNA from a normal control sample yielded one major DNA band, the mutant mRNA sample resulted in two distinct DNA fragments. Sequencing of the patient's two RT-PCR products revealed that the larger molecular weight fragments contained exons 2 and 3 as well as the intervening intronic sequence. The smaller size band from the patient contained the properly spliced exons, similar to the normal control. Western blotting analysis of the expressed protein showed only a faint band in the patient sample in contrast to a robust band in the control. In addition, the enzyme activity of the mutant protein was lower than that of the control protein. The data indicate that homozygous mutation in intron 2 disrupt normal splicing of the gene, leading to lower expression of the MCD protein and MCD deficiency.

Knock-out mouse for Canavan disease: a model for gene transfer to the central nervous system.

BACKGROUND: Canavan disease (CD) is an autosomal recessive leukodystrophy characterized by deficiency of aspartoacylase (ASPA) and increased levels of N-acetylaspartic acid (NAA) in brain and body fluids, severe mental retardation and early death. Gene therapy has been attempted in a number of children with CD. The lack of an animal model has been a limiting factor in developing vectors for the treatment of CD. This paper reports the successful creation of a knock-out mouse for Canavan disease that can be used for gene transfer. METHODS: Genomic library lambda knock-out shuttle (lambdaKOS) was screened and a specific pKOS/Aspa clone was isolated and used to create a plasmid with 10 base pair (bp) deletion of exon four of the murine aspa. Following linearization, the plasmid was electroporated to ES cells. Correctly targeted ES clones were identified following positive and negative selection and confirmed by Southern analysis. Chimeras were generated by injection of ES cells to blastocysts. Germ line transmission was achieved by the birth of heterozygous mice as confirmed by Southern analysis. RESULTS: Heterozygous mice born following these experiments have no overt phenotype. The homozygous mice display neurological impairment, macrocephaly, generalized white matter disease, deficient ASPA activity and high levels of NAA in urine. Magnetic resonance imaging (MRI) and spectroscopy (MRS) of the brain of the homozygous mice show white matter changes characteristic of Canavan disease and elevated NAA levels. CONCLUSION: The newly created ASPA deficient mouse establishes an important animal model of Canavan disease. This model should be useful for developing gene transfer vectors to treat Canavan disease. Vectors for the central nervous system (CNS) and modulation of NAA levels in the brain should further add to the understanding of the pathophysiology of Canavan disease. Data generated from this animal model will be useful for developing strategies for gene therapy in other neurodegenerative diseases.

Novel splice site mutation of aspartoacylase gene in a Turkish patient with Canavan disease.

Canavan disease is a severe, progressive autosomal recessive neurodegenerative leukodystrophy. Canavan disease occurs more frequently among Ashkenazi Jewish individuals with two predominant mutations in the aspartoacylase (ASPA) gene. The disease is less frequent in non-Jewish individuals and the mutations randomly reside on the ASPA gene, with one mutation seen more frequently among patients of European extraction. In the present study we report a novel homozygous donor splice site mutation of intron 4 in a child with first-cousin parents of Turkish extraction.