Patient-Derived Organotypic Epithelial Rafts Model Phenotypes in Juvenile-Onset Recurrent Respiratory Papillomatosis.

Juvenile-onset recurrent respiratory papillomatosis (JoRRP) is driven by human papillomavirus (HPV) low-risk strains and is associated with significant morbidity. While previous studies of 2D cultures have shed light on disease pathogenesis and demonstrated the utility of personalized medicine approaches, monolayer cultures lack the 3D tissue architecture and physiology of stratified, sequentially differentiated mucosal epithelium important in RRP disease pathogenesis. Herein we describe the establishment of JoRRP-derived primary cell populations that retain HPV genomes and viral gene expression in culture.

Cascade Screening for Familial Hypercholesterolemia in South Africa: The Wits FIND-FH Program.

Objective: Due to gene founder effects, familial hypercholesterolemia (FH) has a prevalence of ≈1:80 in populations of Afrikaner ancestry and is a major contributor to premature atherosclerotic cardiovascular disease in South Africans of Jewish and Indian descent. No systematic program exists to identify these families. Furthermore, information regarding FH prevalence in Black Africans is sparse.

Exosomes as a Surrogate Marker for Autophagy in Peripheral Blood, Correlative Data from Phase I Study of Chloroquine in Combination with Carboplatin/Gemcitabine in Advanced Solid Tumors.

Background: Autophagy is a catabolic process, utilized constitutionally by body cells to recycle nutrients and to remove unwanted/damaged intracellular constituents. It is enhanced during periods of stress, such as starvation and hypoxia, aiding in cell survival and it is linked to major cellular processes, such as apoptosis and antigen expression. The process has been extensively studied in vitro models or tumor tissue samples with rare application on human subjects.

Genetic mutations associated with lung cancer metastasis to the brain.

Approximately 90% of all cancer deaths arise from the metastatic spread of primary tumours. Of all the processes involved in carcinogenesis, local invasion and the formation of metastases are clinically the most relevant, but they are the least well understood at the molecular level. As a barrier to metastasis, cells normally undergo an apoptotic process known as 'anoikis', in circulation.

Comparative molecular profiling of HPV-induced squamous cell carcinomas.

Approximately 5% of all cancer incidences result from human papillomavirus (HPV) infection. HPV infection most commonly leads to cancers of the anogenital region or oropharynx. It is unknown whether different HPV-mediated cancers collectively share a molecular signature and it is important to determine if there are targetable alterations common to different types of HPV-positive tumors.

PLK1 inhibition enhances temozolomide efficacy in IDH1 mutant gliomas.

Despite multimodal therapy with radiation and the DNA alkylating agent temozolomide (TMZ), malignant gliomas remain incurable. Up to 90% of grades II-III gliomas contain a single mutant isocitrate dehydrogenase 1 (IDH1) allele. IDH1 mutant-mediated transformation is associated with TMZ resistance; however, there is no clinically available means of sensitizing IDH1 mutant tumors to TMZ.

Olig2-Dependent Reciprocal Shift in PDGF and EGF Receptor Signaling Regulates Tumor Phenotype and Mitotic Growth in Malignant Glioma.

Malignant gliomas exhibit extensive heterogeneity and poor prognosis. Here we identify mitotic Olig2-expressing cells as tumor-propagating cells in proneural gliomas, elimination of which blocks tumor initiation and progression. Intriguingly, deletion of Olig2 resulted in tumors that grow, albeit at a decelerated rate.

Whole genome sequence analysis links chromothripsis to EGFR, MDM2, MDM4, and CDK4 amplification in glioblastoma.

Background: Findings based on recent advances in next-generation sequence analysis suggest that, in some tumors, a single catastrophic event, termed chromothripsis, results in several simultaneous tumorigenic alterations. Previous studies have suggested that glioblastoma (GBM) may exhibit chromothripsis at a higher rate (39%) than other tumors (9%). Primary glioblastoma is an aggressive form of brain cancer that typically appears suddenly in older adults.

ROS1 amplification mediates resistance to gefitinib in glioblastoma cells.

Glioblastoma (GBM) is the most aggressive brain tumor in adults and remains incurable despite multimodal intensive treatment regimens. The majority of GBM tumors show a mutated or overexpressed EGFR, however, tumors treated with tyrosine kinase inhibitors (TKIs) will inevitably recur highlighting the need to identify signalling pathways involved in GBM resistance to these drugs. To this end, we treated GBM cells that overexpress EGFR with increasing concentrations of gefitinib and isolated resistant clones.

Brain Tumor Epidemiology - A Hub within Multidisciplinary Neuro-oncology. Report on the 15th Brain Tumor Epidemiology Consortium (BTEC) Annual Meeting, Vienna, 2014.

The Brain Tumor Epidemiology Consortium (BTEC) is an open scientific forum, which fosters the development of multi-center, international and inter-disciplinary collaborations. BTEC aims to develop a better understanding of the etiology, outcomes, and prevention of brain tumors (http://epi.grants.

Next-generation sequencing technologies: breaking the sound barrier of human genetics.

Demand for new technologies that deliver fast, inexpensive and accurate genome information has never been greater. This challenge has catalysed the rapid development of advances in next-generation sequencing (NGS). The generation of large volumes of sequence data and the speed of data acquisition are the primary advantages over previous, more standard methods.

Whole genome sequencing of glioblastoma multiforme identifies multiple structural variations involved in EGFR activation.

Next generation sequencing has become a powerful tool in dissecting and identifying mutations and genomic structural variants that accompany tumourigenesis. Sequence analysis of glioblastoma multiforme (GBM) illustrates the ability to rapidly identify mutations that may affect phenotype. Approximately 50% of human GBMs overexpress epidermal growth factor receptor (EGFR) which renders the EGFR protein a compelling therapeutic target.

Detection of EGFRvIII mutant DNA in the peripheral blood of brain tumor patients.

Glioblastoma multiforme (GBM) is the most aggressive brain tumor in adults and remains incurable despite multimodal intensive treatment regimens including surgical resection, radiation and chemotherapy. EGFRvIII is a truncated extracellular mutant of the EGF receptor (EGFR) found in about a third of GBMs. It confers enhanced tumorigenic behavior and is associated with chemo- and radio-resistance.

A patient-derived somatic mutation in the epidermal growth factor receptor ligand-binding domain confers increased sensitivity to cetuximab in head and neck cancer.

Background: Cetuximab is an epidermal growth factor receptor (EGFR)-blocking antibody that has been approved for the treatment of patients with head and neck squamous cell carcinoma (HNSCC) and metastatic colorectal cancer, but no predictive biomarkers of activity have been yet identified. Establishment of such biomarkers will help identify a subset of patients that will benefit from cetuximab therapy.

Methods: In this paper, we report on a patient with HNSCC who had a complete tumour regression following treatment with cetuximab given as a single agent after initial surgery and radiation therapy.

Targeting DNA repair mechanisms in cancer.

Preservation of genomic integrity is an essential process for cell homeostasis. DNA-damage response (DDR) promotes faithful transmission of genomes in dividing cells by reversing the extrinsic and intrinsic DNA damage, and is required for cell survival during replication. Radiation and genotoxic drugs have been widely used in the clinic for years to treat cancer but DNA repair mechanisms are often associated with chemo- and radio-resistance.

Functional and molecular interactions between ERK and CHK2 in diffuse large B-cell lymphoma.

Distinct oncogenic signalling cascades have been associated with non-Hodgkin lymphoma. ERK1/2 signalling elicits both transcriptional and post-transcriptional effects through phosphorylation of numerous substrates. Here we report a novel molecular relationship between ERK1/2 and CHK2, a protein kinase that is a key mediator of the DNA damage checkpoint that responds to DNA double-strand breaks.

Polo-like kinases and DNA damage checkpoint: beyond the traditional mitotic functions.

Polo-like kinases (Plks) are a family of serine-threonine kinases that play a pivotal role in cell cycle progression and in cellular response to DNA damage. The Plks are highly conserved from yeast to mammals. There are five Plk family members (Plk1-5) in humans, of which Plk1, is the best characterized.

Absence of polo-like kinase 3 in mice stabilizes Cdc25A after DNA damage but is not sufficient to produce tumors.

The polo-like kinases (Plks1-5) are emerging as an important class of proteins involved in many facets of cell cycle regulation and response to DNA damage and stress. Here we show that Plk3 phosphorylates the key cell cycle protein phosphatase Cdc25A on two serine residues in its cyclinB/cdk1 docking domain and regulates its stability in response to DNA damage. We generated a Plk3 knock-out mouse and show that Cdc25A protein from Plk3-deficient cells is less susceptible to DNA damage-mediated degradation than cells with functional Plk3.

A human cancer-predisposing polymorphism in Cdc25A is embryonic lethal in the mouse and promotes ASK-1 mediated apoptosis.

Background: Failure to regulate the levels of Cdc25A phosphatase during the cell cycle or during a checkpoint response causes bypass of DNA damage and replication checkpoints resulting in genomic instability and cancer. During G1 and S and in cellular response to DNA damage, Cdc25A is targeted for degradation through the Skp1-cullin-β-TrCP (SCFβ-TrCP) complex. This complex binds to the Cdc25A DSG motif which contains serine residues at positions 82 and 88.

Chk2*1100delC Acts in synergy with the Ron receptor tyrosine kinase to accelerate mammary tumorigenesis in mice.

The CHEK2 (Chk2 in mice) polymorphic variant, CHEK2*1100delC, leads to genomic instability and is associated with an increased risk for breast cancer. The Ron receptor tyrosine kinase is overexpressed in a large fraction of human breast cancers. Here, we asked whether the low penetrance Chk2*1100delC allele alters the tumorigenic efficacy of Ron in the development of mammary tumors in a mouse model.

The novel mouse Polo-like kinase 5 responds to DNA damage and localizes in the nucleolus.

Polo-like kinases (Plk1-4) are emerging as an important class of proteins involved in many aspects of cell cycle regulation and response to DNA damage. Here, we report the cloning of a fifth member of the polo-like kinase family named Plk5. DNA and protein sequence analyses show that Plk5 shares more similarities with Plk2 and Plk3 than with Plk1 and Plk4.

Mice with the CHEK2*1100delC SNP are predisposed to cancer with a strong gender bias.

The CHEK2 kinase (Chk2 in mouse) is a member of a DNA damage response pathway that regulates cell cycle arrest at cell cycle checkpoints and facilitates the repair of dsDNA breaks by a recombination-mediated mechanism. There are numerous variants of the CHEK2 gene, at least one of which, CHEK2*1100delC (SNP), associates with breast cancer. A mouse model in which the wild-type Chk2 has been replaced by a Chk2*1100delC allele was tested for elevated risk of spontaneous cancer and increased sensitivity to challenge by a carcinogenic compound.

Prolactin confers resistance against cisplatin in breast cancer cells by activating glutathione-S-transferase.

Resistance to chemotherapy is a major obstacle for successful treatment of breast cancer patients. Given that prolactin (PRL) acts as an anti-apoptotic/survival factor in the breast, we postulated that it antagonizes cytotoxicity by chemotherapeutic drugs. Treatment of breast cancer cells with PRL caused variable resistance to taxol, vinblastine, doxorubicin and cisplatin.

The breast cancer susceptibility allele CHEK2*1100delC promotes genomic instability in a knock-in mouse model.

Allelic variants of CHEK2 contribute to an elevated risk for human breast cancer and possibly other cancer types. In particular, the CHEK2*1100delC polymorphic variant has been identified as a low-penetrance breast cancer susceptibility allele in breast cancer families with wild type BRCA1 and BRCA2. To better understand the molecular basis by which this allele increases risk for disease, we have generated a mouse in which the wild type CHEK2 (Chk2 in mouse) allele has been replaced with the 1100delC variant.

Priming phosphorylation of Chk2 by polo-like kinase 3 (Plk3) mediates its full activation by ATM and a downstream checkpoint in response to DNA damage.

The tumor suppressor gene Chk2 encodes a serine/threonine kinase that signals DNA damage to cell cycle checkpoints. In response to ionizing radiation, Chk2 is phosphorylated on threonine 68 (T68) by ataxia-telangiectasia mutated (ATM) protein leading to its activation. We have previously shown that polo-like kinase 3 (Plk3), a protein involved in DNA damage checkpoint and M-phase functions, interacts with and phosphorylates Chk2.