AKT1 and MYC induce distinctive metabolic fingerprints in human prostate cancer.

Cancer cells may overcome growth factor dependence by deregulating oncogenic and/or tumor-suppressor pathways that affect their metabolism, or by activating metabolic pathways de novo with targeted mutations in critical metabolic enzymes. It is unknown whether human prostate tumors develop a similar metabolic response to different oncogenic drivers or a particular oncogenic event results in its own metabolic reprogramming. Akt and Myc are arguably the most prevalent driving oncogenes in prostate cancer. Mass spectrometry-based metabolite profiling was performed on immortalized human prostate epithelial cells transformed by AKT1 or MYC, transgenic mice driven by the same oncogenes under the control of a prostate-specific promoter, and human prostate specimens characterized for the expression and activation of these oncoproteins. Integrative analysis of these metabolomic datasets revealed that AKT1 activation was associated with accumulation of aerobic glycolysis metabolites, whereas MYC overexpression was associated with dysregulated lipid metabolism. Selected metabolites that differentially accumulated in the MYC-high versus AKT1-high tumors, or in normal versus tumor prostate tissue by untargeted metabolomics, were validated using absolute quantitation assays. Importantly, the AKT1/MYC status was independent of Gleason grade and pathologic staging. Our findings show how prostate tumors undergo a metabolic reprogramming that reflects their molecular phenotypes, with implications for the development of metabolic diagnostics and targeted therapeutics.

Global levels of H3K27me3 track with differentiation in vivo and are deregulated by MYC in prostate cancer.

Cancer cells and stem cells share a number of biological characteristics including abundant amounts of decondensed chromatin. However, the molecular correlates and the factors involved in altering chromatin structure in cancer cells are not well known. Here, we report that less differentiated stem-like cells in the basal compartment of human and mouse prostate contain lower levels of the polycomb heterochromatin marker H3K27me3 than more differentiated luminal cells. This link to differentiated normal cells is also found in a number of other human and rodent tissues characterized by hierarchical differentiation. In addition to MYC's traditional role as a gene-specific transcription factor, recent studies indicate that MYC also affects global chromatin structure where it is required to maintain "open" or active chromatin. We now demonstrate that in both MYC-driven prostate cancers in mice and human prostate cancers, global levels of H3K27me3 are reduced in prostatic intraepithelial neoplasia and invasive adenocarcinoma lesions. Moreover, decreased levels of H3K27me3 correlate with increased markers of disease aggressiveness (eg, Gleason score and pathological stage). In vitro, experimentally forced reductions in MYC levels result in increased global levels of H3K27me3. These findings suggest that increased levels of decondensed chromatin in both normal progenitor cells and cancer cells are associated with global loss of H3K27me3, which is linked to MYC overexpression.

Alterations in nucleolar structure and gene expression programs in prostatic neoplasia are driven by the MYC oncogene.

Increased nucleolar size and number are hallmark features of many cancers. In prostate cancer, nucleolar enlargement and increased numbers are some of the earliest morphological changes associated with development of premalignant prostate intraepithelial neoplasia (PIN) lesions and invasive adenocarcinomas. However, the molecular mechanisms that induce nucleolar alterations in PIN and prostate cancer remain largely unknown. We verify that activation of the MYC oncogene, which is overexpressed in most human PIN and prostatic adenocarcinomas, leads to formation of enlarged nucleoli and increased nucleolar number in prostate luminal epithelial cells in vivo. In prostate cancer cells in vitro, MYC expression is needed for maintenance of nucleolar number, and a nucleolar program of gene expression. To begin to decipher the functional relevance of this transcriptional program in prostate cancer, we examined FBL (encoding fibrillarin), a MYC target gene, and report that fibrillarin is required for proliferation, clonogenic survival, and proper ribosomal RNA accumulation/processing in human prostate cancer cells. Further, fibrillarin is overexpressed in PIN lesions induced by MYC overexpression in the mouse prostate, and in human clinical prostate adenocarcinoma and PIN lesions, where its expression correlates with MYC levels. These studies demonstrate that overexpression of the MYC oncogene increases nucleolar number and size and a nucleolar program of gene expression in prostate epithelial cells, thus providing a molecular mechanism responsible for hallmark nucleolar alterations in prostatic neoplasia.

MYC overexpression induces prostatic intraepithelial neoplasia and loss of Nkx3.1 in mouse luminal epithelial cells.

Lo-MYC and Hi-MYC mice develop prostatic intraepithelial neoplasia (PIN) and prostatic adenocarcinoma as a result of MYC overexpression in the mouse prostate. However, prior studies have not determined precisely when, and in which cell types, MYC is induced. Using immunohistochemistry (IHC) to localize MYC expression in Lo-MYC transgenic mice, we show that morphological and molecular alterations characteristic of high grade PIN arise in luminal epithelial cells as soon as MYC overexpression is detected. These changes include increased nuclear and nucleolar size and large scale chromatin remodeling. Mouse PIN cells retained a columnar architecture and abundant cytoplasm and appeared as either a single layer of neoplastic cells or as pseudo-stratified/multilayered structures with open glandular lumina-features highly analogous to human high grade PIN. Also using IHC, we show that the onset of MYC overexpression and PIN development coincided precisely with decreased expression of the homeodomain transcription factor and tumor suppressor, Nkx3.1. Virtually all normal appearing prostate luminal cells expressed high levels of Nkx3.1, but all cells expressing MYC in PIN lesions showed marked reductions in Nkx3.1, implicating MYC as a key factor that represses Nkx3.1 in PIN lesions. To determine the effects of less pronounced overexpression of MYC we generated a new line of mice expressing MYC in the prostate under the transcriptional control of the mouse Nkx3.1 control region. These "Super-Lo-MYC" mice also developed PIN, albeit a less aggressive form. We also identified a histologically defined intermediate step in the progression of mouse PIN into invasive adenocarcinoma. These lesions are characterized by a loss of cell polarity, multi-layering, and cribriform formation, and by a "paradoxical" increase in Nkx3.1 protein. Similar histopathological changes occurred in Hi-MYC mice, albeit with accelerated kinetics. Our results using IHC provide novel insights that support the contention that MYC overexpression is sufficient to transform prostate luminal epithelial cells into PIN cells in vivo. We also identified a novel histopathologically identifiable intermediate step prior to invasion that should facilitate studies of molecular pathway alterations occurring during early progression of prostatic adenocarcinomas.

Experimental infection of an African dormouse (Graphiurus kelleni) with monkeypox virus.

Suitable animal models are needed to study monkeypox virus (MPXV) as human monkeypox clinically resembles smallpox and MPXV is a zoonotic and potential bioterroristic agent. We have demonstrated that a species of African dormice, Graphiurus kelleni, is susceptible to a lethal infection of MPXV and that MPXV replicated in multiple organs of this species. Following intranasal administration, MPXV replicated locally in the nasal mucosa causing necrosis and hemorrhage with subsequent systemic spread to lymph nodes, spleen, liver, and other tissues where it caused severe necrosis and/or hemorrhage leading to death. The dormouse model was validated for testing prophylactic (Dryvax vaccine) and therapeutic (cidofovir) test articles against intranasal challenges with MPXV.

How to conduct effective skill building workshops.

Skill building workshops need to be successful learning events that provide value for money. The strategies in this article are based on a review of the literature and evaluations received from workshop participants who have attended the many workshops conducted as part of the Primary Health Care Research Evaluation and Development (PHCRED) strategy.

Diagnosis and attempted surgical repair of hemivertebrae in an African penguin (Spheniscus demersus).

Spinal injuries and congenital or developmental spinal deformities have rarely been reported in pet birds, and treatment for these conditions is even less often described. In poultry, spinal and leg deformities have been well documented, but treatment of the individual is not considered, because affected individuals are typically culled. A 10-week-old male African black-footed penguin (Spheniscus demersus) from the penguin exhibit at the Maryland Zoo in Baltimore was evaluated for ataxia, weakness, and motor deficits and was diagnosed with a spinal deformity. Further investigation by using magnetic resonance imaging was conducted, and the penguin subsequently underwent an attempted surgical repair of the malformation. The penguin never regained normal motor control and was found dead 4 weeks after the surgery. Necropsy results revealed hemivertebrae and compression of the spinal cord with associated myositis. Although attempted treatment was unsuccessful in this case, this report illustrates the diagnostic and treatment challenges of avian spinal disease.

Human monkeypox: an emerging zoonotic disease.

Zoonotic monkeypox virus is maintained in a large number of rodent and, to a lesser extent, nonhuman primate species in West and central Africa. Although monkeypox virus was discovered in 1958, the prototypic human cases were not witnessed until the early 1970s. Before this time, it is assumed that infections were masked by smallpox, which was then widely endemic. Nevertheless, since the 1970s, reported monkeypox virus infections of humans have escalated, as have outbreaks with reported human-to-human transmission. This increase is likely due to numerous factors, such as enhanced surveillance efforts, environmental degradation and human urbanization of areas where monkeypox virus is maintained in its animal reservoir(s) and, consequently, serve as a nidus for human infection. Furthermore, viral genetic predispositions enable monkeypox virus to infect many animal species, represented in expansive geographic ranges. Monkeypox virus was once restricted to specific regions of Africa, but its environ has expanded, in one case intercontinentally--suggesting that human monkeypox infections could continue to intensify. As a zoonotic agent, monkeypox virus is far less sensitive to typical eradication measures since it is maintained in wild-animal populations. Moreover, human vaccination is becoming a less viable option to control poxvirus infections in today's increasingly immunocompromised population, particularly with the emergence of HIV in Sub-Saharan Africa. An increased frequency of human monkeypox virus infections, especially in immunocompromised individuals, may permit monkeypox virus to evolve and maintain itself independently in human populations.