Essential role of Drosophila black-pearl is mediated by its effects on mitochondrial respiration.

Black-pearl (Blp) is a highly conserved, essential inner-mitochondrial membrane protein. The yeast Blp homologue, Magmas/Pam16, is required for mitochondrial protein transport, growth, and survival. Our purpose was to determine the role of Drosophila Blp in mitochondrial function, cell survival, and proliferation. To this end, we performed mitotic recombination in Drosophila melanogaster, RNAi-mediated knockdown, MitoTracker staining, measurement of reactive oxygen species (ROS), flow cytometry, electron transport chain complex assays, and hemocyte isolation from Drosophila larvae. Proliferation-defective, Blp-deficient Drosophila Schneider cells exhibited mitochondrial membrane depolarization, a 60% decrease in ATP levels, increased amounts of ROS (3.5-fold), cell cycle arrest, and activation of autophagy that were associated with a selective 65% reduction of cytochrome c oxidase activity. N-acetyl cysteine (NAC) rescued Blp-RNAi-treated cells from cell cycle arrest, indicating that increased production of ROS is the primary cause of the proliferation and survival defects in Blp-depleted cells. blp hypomorph larvae had a 35% decreased number of plasmatocytes with a 45% reduced active mitochondrial staining and their viability was increased 2-fold by administration of NAC, which blocked melanotic lesions. Loss of Blp decreases cytochrome c oxidase activity and uncouples oxidative phosphorylation, causing ROS production, which selectively affects mitochondria-rich plasmatocyte survival and function, leading to melanotic lesions in Blp-deficient flies.

Design, synthesis, and biological activity of novel Magmas inhibitors.

Magmas (mitochondria associated, granulocyte-macrophage colony stimulating factor signaling molecule), is a highly conserved and essential gene, expressed in all cell types. We designed and synthesized several small molecule Magmas inhibitors (SMMI) and assayed their effects on proliferation in yeast. We found that the most active compound 9 inhibited growth at the 4 µM scale. This compound was shown by fluorometric titration to bind to Magmas with a K(d)=33 µM. Target specificity of the lead compound was established by demonstrating direct binding of the compound to Magmas and by genetic studies. Molecular modeling suggested that the inhibitor bound at the predicted site in Magmas.

Ovarian Cancer, Cancer Stem Cells and Current Treatment Strategies: A Potential Role of Magmas in the Current Treatment Methods.

Epithelial ovarian cancer (EOC) constitutes 90% of ovarian cancers (OC) and is the eighth most common cause of cancer-related death in women. The cancer histologically and genetically is very complex having a high degree of tumour heterogeneity. The pathogenic variability in OC causes significant impediments in effectively treating patients, resulting in a dismal prognosis. Disease progression is predominantly influenced by the peritoneal tumour microenvironment rather than properties of the tumor and is the major contributor to prognosis. Standard treatment of OC patients consists of debulking surgery, followed by chemotherapy, which in most cases end in recurrent chemoresistant disease. This review discusses the different origins of high-grade serous ovarian cancer (HGSOC), the major sub-type of EOC. Tumour heterogeneity, genetic/epigenetic changes, and cancer stem cells (CSC) in facilitating HGSOC progression and their contribution in the circumvention of therapy treatments are included. Several new treatment strategies are discussed including our preliminary proof of concept study describing the role of mitochondria-associated granulocyte macrophage colony-stimulating factor signaling protein (Magmas) in HGSOC and its unique potential role in chemotherapy-resistant disease.

Severe Evans syndrome with multi-system involvement is a distinct immunodeficiency disorder.

A female infant who presented with autoimmune hemolytic anemia and thrombocytopenia subsequently developed hepatic, dermatologic, renal, pulmonary, gastrointestinal, endocrine, and nervous system involvement. Prolonged and intensive treatment with prednisone, IVIG, mycophenolate mofetil, and anti-CD20 and anti-CD52 antibodies was necessary to control the symptoms. Laboratory evaluation showed normal lymphocyte subsets and function. There was normal Foxp3 and CD25 expression, no increased CD4(-)CD8(-) T-cell population, and the AIRE and Fas genes were without mutations. These features place the patient at the most severe portion of the Evans syndrome spectrum, and suggest that this case may represent a rare, new immunodeficiency disorder.

Therapeutic strategies for targeting mononuclear phagocytes in cancer.

The initiation and progression of cancer is dependent on factors both intrinsic and extrinsic to the malignant cells. Stromal, vascular endothelial, and inflammatory cells are the principal normal populations that support tumors by supplying factors and nutrients. The mononuclear phagocyte lineage, which includes monocytes, macrophages, and dendritic cells is of particular clinical interest because lineage members can enhance tumor angiogenesis and metastasis, or alternately contribute to tumor destruction. Thus therapies that regulate these cells represent an innovative approach for improving patient survival in childhood cancer.

New roles for mononuclear phagocytes in cancer biology.

The primary focus in the pathogenesis and treatment of human malignancies has been the tumor cell. However, the biologic properties of a malignancy are not all intrinsically determined. Interactions between heterogeneous cell populations influence the growth and survival of both normal and malignant cells. Studies defining the origin of endothelial cells involved in tumor angiogenesis first demonstrated the contributions of normal cellular environment. Recently, the mononuclear phagocyte lineage has been found to have biologically and clinically significant tumor enhancing and tumor suppressive effects. This article reviews the multiple roles of mononuclear phagocytes in cancer biology. A companion manuscript (J Pediatr Hematol Oncol. 2008, in press) describes the targeting of these cells for therapeutic benefit. Incorporating these strategies into future childhood cancer protocols could be an innovative approach for improving patient outcome.

Accumulation of an intron-retained mRNA for granulocyte macrophage-colony stimulating factor receptor common beta chain in neutrophils of myelodysplastic syndromes.

We recently identified a reduction in the neutrophil surface expression of common beta chain (beta c) of the receptor for granulocyte macrophage-colony stimulating factor (GM-CSF) in the patients with myelodysplastic syndromes (MDS). To determine the etiology of the impaired beta c expression, beta c mRNA from neutrophilic granulocytes of MDS patients and healthy controls was analyzed by a combination of direct reverse transcriptase-polymerase chain reaction-based single-strand conformational polymorphism and sequencing. Nine different beta c transcripts were detected, but none was specific for MDS. However, one of the transcripts (beta c79) containing a 79-base intron insertion between exons V and VI was significantly increased in MDS. This 27-kd isoform consisted of the beta c N-terminal 182 amino acids followed by a new 84-amino-acid sequence. beta c79 was overexpressed in all MDS subtypes. No genomic mutations were detected within the intron or at the intron/exon boundaries. The isoform is predominantly located in the cytoplasm by Western blot analysis and was unable to generate high-affinity binding sites or transduce a signal for proliferation when coexpressed with the receptor for human GM-CSF alpha chain. Our study suggests that the accumulation of the abnormal beta c transcripts with intron V retention results in the reduction in cell-surface expression of beta c observed in MDS.

Magmas expression in neoplastic human prostate.

Magmas, is a 13-kDa mitochondrial protein which is ubiquitously expressed in eukaryotic cells. It was identified as a granulocyte-macrophage-colony stimulating factor (GM-CSF) inducible gene in hematopoietic cells and has a key role in the transport of mitochondrial proteins in yeast. Because GM-CSF receptor levels are elevated in prostate cancer, Magmas expression was examined in normal and neoplastic tissue. Magmas protein levels were barely detectable in non-neoplastic prostate glands. Increased amounts were observed in some samples of intraepithelial neoplasia. Approximately one half of the adenocarcinoma samples examined had weak Magmas expression, while the remainder had intermediate to high levels. The increased Magmas observed in malignant tissue was a result of higher protein expression and not from changes in mitochondrial content. Interestingly, in some patients, the normal prostate tissue had more Magmas message than the malignant portion. The results indicated that Magmas expression in prostate cancer is heterogeneous and independent of clinical stage and Gleason score. Further studies are needed to determine if Magmas expression has prognostic significance in prostate cancer.

Acute myeloid leukemia presenting as spinal cord compression.

We report the findings of a 10-year-old boy who presented to a pediatric emergency department with symptoms of spinal cord compression. Radiological imaging demonstrated multiple soft tissue masses in the head and spine. The surgical pathology showed that the masses were comprised of myeloid leukemia cells. These findings were consistent with those observed on bone marrow aspiration. The characteristics and management of extramedullary leukemia are discussed.

Developmental expression of Magmas in murine tissues and its co-expression with the GM-CSF receptor.

Magmas is a protein that is involved in GM-CSF signaling in a myeloid cell line. Its precise role in the signal transduction process is unclear. To accurately characterize Magmas expression in a variety of cells, mouse embryos and adult murine tissues were analyzed for both mRNA and protein content. Magmas expression was detected as early as the day 6.5 embryo. The level of expression was developmentally regulated. During embryogenesis, elevated Magmas was observed in several structures, including heart, liver, notochord, choroid plexus, cervical ganglion, and nasal mucosa. Muscle, pancreas, intestinal mucosa, and testes were among the adult tissues with high Magmas expression. Most cell types, including hepatocytes and skeletal, smooth, and cardiac myocytes, also expressed the GM-CSF receptor (GMR) but the relative tissue levels of GMR were not always proportional to Magmas. The expression patterns suggest that Magmas has a role in both developing and mature tissues.

Thrombotic thrombocytopenic purpura in a newborn.

This report describes a newborn who presented with hyperbilirubinemia and thrombocytopenia. The patient recovered after treatment with antibiotics, phototherapy, and a platelet transfusion. Analysis of the plasma von Willebrand factor-cleaving metalloprotease, ADAMTS13, revealed low protease activity in the patient and her two siblings, and a mild deficiency in both parents. These results confirmed the clinical suspicion of hereditary thrombotic thrombocytopenic purpura (TTP). Although most cases of thrombocytopenia and hyperbilirubinemia in the newborn period are caused by other causes, genetic deficiency of ADAMTS13 may not be as uncommon as previously believed. Early diagnosis may have important implications for the patients.

Verification of supraselective drug delivery for retinoblastoma using intra-arterial gadolinium.

We present a description of retinoblastoma treated with supraselective intra-arterial chemotherapy, demonstrating selective delivery of the infused chemotherapeutic agent into the tumor bed by MRI. A 7-month-old presented with group E (international classification) unilateral retinoblastoma. We treated the patient with several rounds of intra-ophthalmic artery melphalan. Gadolinium was infused along with melphalan to visualize the distribution of this chemotherapeutic drug. Intraoperative MRI was obtained within 15 min after treatment and showed increased enhancement of the tumor and subretinal space. We demonstrate here that supraselective administration of chemotherapy into the ophthalmic artery appears to result in drug delivery to the tumor and subretinal space.

Verification of supraselective drug delivery for retinoblastoma using intra-arterial gadolinium.

We present a description of retinoblastoma treated with supraselective intra-arterial chemotherapy, demonstrating selective delivery of the infused chemotherapeutic agent into the tumor bed by MRI. A 7-month-old presented with group E (international classification) unilateral retinoblastoma. We treated the patient with several rounds of intra-ophthalmic artery melphalan. Gadolinium was infused along with melphalan to visualize the distribution of this chemotherapeutic drug. Intraoperative MRI was obtained within 15 min after treatment and showed increased enhancement of the tumor and subretinal space. We demonstrate here that supraselective administration of chemotherapy into the ophthalmic artery appears to result in drug delivery to the tumor and subretinal space.

The yeast magmas ortholog pam16 has an essential function in fermentative growth that involves sphingolipid metabolism.

Magmas is a growth factor responsive gene encoding an essential mitochondrial protein in mammalian cells. Pam16, the Magmas ortholog in Saccharomyces cerevisiae, is a component of the presequence translocase-associated motor. A temperature-sensitive allele (pam16-I61N) was used to query an array of non-essential gene-deletion strains for synthetic genetic interactions. The pam16-I61N mutation at ambient temperature caused synthetic lethal or sick phenotypes with genes involved in lipid metabolism, perixosome synthesis, histone deacetylation and mitochondrial protein import. The gene deletion array was also screened for suppressors of the pam16-I61N growth defect to identify compensatory pathways. Five suppressor genes were identified (SUR4, ISC1, IPT1, SKN1, and FEN1) and all are involved in sphingolipid metabolism. pam16-I61N cells cultured in glucose at non-permissive temperatures resulted in rapid growth inhibition and G1 cell cycle arrest, but cell viability was maintained. Altered mitochondria morphology, reduced peroxisome induction in glycerol/ethanol and oleate, and changes in the levels of several sphingolipids including C18 alpha-hydroxy-phytoceramide, were also observed in the temperature sensitive strain. Deletion of SUR4, the strongest suppressor, reversed the temperature sensitive fermentative growth defect, the morphological changes and the elevated levels of C18 alpha-hydroxy phytoceramide in pam16-I61N. Deletion of the other four suppressor genes had similar effects on C18 alpha-hydroxy-phytoceramide levels and restored proliferation to the pam16-I61N strain. In addition, pam16-I61N inhibited respiratory growth, likely by reducing cardiolipin, which is essential for mitochondrial function. Our results suggest that the pleiotropic effects caused by impaired Pam16/Magmas function are mediated in part by changes in lipid metabolism.

A unique case of rhabdoid tumor presenting as hemoperitoneum in an infant.

We report the first pediatric case of an extrarenal, noncentral nervous system, diffusely metastatic, gastrointestinal rhabdoid tumor in a 106-day-old, previous 25-week preterm infant. The unusual clinical presentation, the diagnosis, and biology of this tumor as well as the etiology of hemoperitoneum in neonates and infants are discussed.

A syndrome of holoprosencephaly, recurrent infections, and monocytosis.

We describe three siblings with holoprosencephaly, recurrent infections, and increased peripheral blood monocytes. These children were born to apparently healthy parents in a family with one unaffected child. Affected individuals had microcephaly, severe developmental delay, failure to thrive, and brachydactyly. The clinical courses were complicated by endocrine dysfunction, multiple respiratory, and skin infections. Laboratory studies showed normal karyotypes, normal lymphocyte function, and a peripheral blood monocytosis with markedly abnormal morphology. Mutation analysis of the seven genes (SHH, ZIC2, SIX3, TGI, FTDGF1, GLI2, and PTCH) known to be involved in holoprosencephaly was normal. This is the first report demonstrating an association between abnormal mononuclear phagocytes and holoprosencephaly.

Successful treatment of a patient with mixed warm and cold antibody mediated Evans syndrome and glucose intolerance.

Thrombocytopenia and autoimmune hemolytic anemia (Evans syndrome) with the presence of both warm and cold autoantibodies (mixed type) are rare in the pediatric age group. This condition may be associated with other autoimmune disorders and is notoriously difficult to treat. This case describes an adolescent male who presented with rapid onset Evans syndrome and diabetes. After failing to respond to high dose prednisone and intravenous immunoglobulin, the patient was successfully treated with monoclonal antibody against CD20 (anti-CD20). This suggests that anti-CD20 is a valuable treatment for severe warm and cold antibody mediated Evans syndrome, and possibly for select cases of antibody mediated diabetes.

Abdominal pain in a patient with osteosarcoma.

Abdominal pain often occurs in patients receiving chemotherapy. The authors describe a patient with osteosarcoma who developed severe right-sided abdominal discomfort several days after being admitted for fever, neutropenia, and mucositis. Unexpectedly, the patient's pain was not therapy-related, but rather was caused by a midline pelvic mass.

Successful treatment of an unresectable choroid plexus carcinoma in a patient with Li-Fraumeni syndrome.

Choroid plexus carcinoma (CPC) is an uncommon central nervous system tumor requiring complete surgical excision for favorable outcome. The authors report the successful treatment of a 2-year-old patient with widely disseminated CPC and Li-Fraumeni syndrome. Following a partial resection of the tumor the patient received chemotherapy consisting of cyclophosphamide, etoposide, and carboplatin. There were no additional surgical procedures and radiation was not administered. Remarkably, the patient remains without evidence of active disease more than 3 years from the completion of therapy. Additional studies are necessary to determine whether this treatment plan can be beneficial to other patients with CPC and whether the patient's p53 mutation had an effect on outcome.