DNA Damage and Cytokine Production in Non-Target Irradiated Lymphocytes

In advanced radiotherapy, treatment of the tumor with high-intensity modulated fields is balanced with normal tissue sparing. However, the non-target dose delivered to surrounding healthy tissue within the irradiated volume is a potential cause for concern. Whether the effects observed are caused after exposure to out-of-field radiation or bystander effects through neighboring irradiated cells is not fully understood. The goal of this study was to determine the effect of exposure to out-of-field radiation in lymphocyte cell lines and primary blood cells. The role of cellular radiosensitivity in altering bystander responses in out-of-field exposed cells was also investigated. Target cells were positioned in a phantom in the center of the radiation field (in-field dose) and exposed to 2 Gy irradiation. Lymphocyte cell lines (C1, AT3ABR, Jurkat, THP-1, AT2Bi and AT3Bi) and peripheral blood were placed 1 cm away from the radiation field edge (out-offield dose) and received an average dose of 10.8 6 4.2 cGy. Double-stranded DNA damage, cell growth and gene expression were measured in the out-of-field cells. Radiosensitive AT3ABR and primary blood cells demonstrated the largest increase in c-H2AX foci after irradiation. Exposure of normal cells to bystander factors from irradiated radiosensitive cell lines also increased DNA damage. Expression of IL-1, IL-6, TNFa and TGFb after addition of bystander factors from radiosensitive cells showed differential effects in normally responding cells, with some evidence of an adaptive response observed. Exposure to out-of-field radiation induces DNA damage and reduces growth in radiosensitive cells. Bystander factors produced by directly irradiated cells in combination with out-of-field exposure may upregulate pro- and anti-inflammatory genes in responding cells of different radiosensitivities, with the potential of affecting the tumor microenvironment. A greater understanding of the radiobiological response in normal cells outside the primary treatment field would assist in radiation treatment planning and in reducing early and late toxicities

Voriconazole-induced periostitis post lung transplantation

Voriconazole is a broad-spectrum triazole antifungal used to treatinvasive fungal infections. It is commonly used prophylactically in immunocompromized patient cohorts, including transplant recipients. Diffuse periostitis is a very rare complication of chronic voricona zole use. It is associated with diffuse bone pain, elevated serum alkaline phosphatase and fluorine levels. Characteristic imaging findings include periosteal thickening with a dense, nodular, irregular and often bilateral pattern. We describe the case of a 71-year-old female who presented with multifocal bone pain six years following double lung transplantation. Her post transplantation course had been complicated by a life threatening episode of sepsis secondary to Scedosporium apiospermum, a rare invasive fungal infection following which lifelong prophylaxis with oral Voriconazole was commenced. We discuss the characteristic clinical and imaging manifestations of this rare condition

Identification of Different Classes of Luminal Progenitor Cells within Prostate Tumors

Primary prostate cancer almost always has a luminal phenotype. However, little is known about the stem/progenitor properties of transformed cells within tumors. Using the aggressive Pten/Tp53-null mouse model of prostate cancer, we show that two classes of luminal progenitors exist within a tumor. Not only did tumors contain previously described multipotent progenitors, but also a major population of committed luminal progenitors. Luminal cells, sorted directly from tumors or grown as organoids, initiated tumors of adenocarcinoma or multilineage histological phenotypes, which is consistent with luminal and multipotent differentiation potentials, respectively. Moreover, using organoids we show that the ability of luminal-committed progenitors to self-renew is a tumor-specific property, absent in benign luminal cells. Finally, a significant fraction of luminal progenitors survived in vivo castration. In all, these data reveal two luminal tumor populations with different stem/progenitor cell capacities, providing insight into prostate cancer cells that initiate tumors and can influence treatment response

<em>TMPRSS2-</em> Driven <em>ERG</em> Expression <em>In Vivo</em> Increases Self-Renewal and Maintains Expression in a Castration Resistant Subpopulation

<div><p>Genomic rearrangements commonly occur in many types of cancers and often initiate or alter the progression of disease. Here we describe an in vivo mouse model that recapitulates the most frequent rearrangement in prostate cancer, the fusion of the promoter region of <em>TMPRSS2</em> with the coding region of the transcription factor, <em>ERG</em>. A recombinant bacterial artificial chromosome including an extended <em>TMPRSS2</em> promoter driving genomic <em>ERG</em> was constructed and used for transgenesis in mice. <em>TMPRSS2-ERG</em> expression was evaluated in tissue sections and FACS-fractionated prostate cell populations. In addition to the anticipated expression in luminal cells, <em>TMPRSS2-ERG</em> was similarly expressed in the Sca-1^hi/EpCAM⁺ basal/progenitor fraction, where expanded numbers of clonogenic self-renewing progenitors were found, as assayed by in vitro sphere formation. These clonogenic cells increased intrinsic self renewal in subsequent generations. In addition, ERG dependent self-renewal and invasion in vitro was demonstrated in prostate cell lines derived from the model. Clinical studies have suggested that the <em>TMPRSS2-ERG</em> translocation occurs early in prostate cancer development. In the model described here, the presence of the <em>TMPRSS2-ERG</em> fusion alone was not transforming but synergized with heterozygous <em>Pten</em> deletion to promote PIN. Taken together, these data suggest that one function of <em>TMPRSS2-ERG</em> is the expansion of self-renewing cells, which may serve as targets for subsequent mutations. Primary prostate epithelial cells demonstrated increased post transcriptional turnover of ERG compared to the TMPRSS2-ERG positive VCaP cell line, originally isolated from a prostate cancer metastasis. Finally, we determined that <em>TMPRSS2-ERG</em> expression occurred in both castration-sensitive and resistant prostate epithelial subpopulations, suggesting the existence of androgen-independent mechanisms of TMPRSS2 expression in prostate epithelium.</p> </div

Identification of Different Classes of Luminal Progenitor Cells within Prostate Tumors

Primary prostate cancer almost always has a luminal phenotype. However, little is known about the stem/progenitor properties of transformed cells within tumors. Using the aggressive Pten/Tp53-null mouse model of prostate cancer, we show that two classes of luminal progenitors exist within a tumor. Not only did tumors contain previously described multipotent progenitors, but also a major population of committed luminal progenitors. Luminal cells, sorted directly from tumors or grown as organoids, initiated tumors of adenocarcinoma or multilineage histological phenotypes, which is consistent with luminal and multipotent differentiation potentials, respectively. Moreover, using organoids we show that the ability of luminal-committed progenitors to self-renew is a tumor-specific property, absent in benign luminal cells. Finally, a significant fraction of luminal progenitors survived in vivo castration. In all, these data reveal two luminal tumor populations with different stem/progenitor cell capacities, providing insight into prostate cancer cells that initiate tumors and can influence treatment response