MicroRNA Analysis of ATM-Deficient Cells Indicate PTEN and CCDN1 as Potential Biomarkers of Radiation Response.

Genetic and epigenetic profile changes associated with individual radiation sensitivity are well documented and have led to enhanced understanding of the mechanisms of the radiation-induced DNA damage response. However, the search continues to identify reliable biomarkers of individual radiation sensitivity. Herein, we report on a multi-biomarker approach using traditional cytogenetic biomarkers, DNA damage biomarkers and transcriptional microRNA (miR) biomarkers coupled with their potential gene targets to identify radiosensitivity in ataxia-telangiectasia mutated (ATM)-deficient lymphoblastoid cell lines (LCL); ATM-proficient cell lines were used as controls. Cells were 0.05 and 0.5 Gy irradiated, using a linear accelerator, with sham-irradiated cells as controls. At 1 h postirradiation, cells were fixed for γ-H2AX analysis as a measurement of DNA damage, and cytogenetic analysis using the G2 chromosomal sensitivity assay, G-banding and FISH techniques. RNA was also isolated for genetic profiling by microRNA (miR) and RT-PCR analysis. A panel of 752 miR were analyzed, and potential target genes, phosphatase and tensin homolog (PTEN) and cyclin D1 (CCND1), were measured. The cytogenetic assays revealed that although the control cell line had functional cell cycle checkpoints, the radiosensitivity of the control and AT cell lines were similar. Analysis of DNA damage in all cell lines, including an additional control cell line, showed elevated γ-H2AX levels for only one AT cell line. Of the 752 miR analyzed, eight miR were upregulated, and six miR were downregulated in the AT cells compared to the control. Upregulated miR-152-3p, miR-24-5p and miR-92-15p and all downregulated miR were indicated as modulators of PTEN and CCDN1. Further measurement of both genes validated their potential role as radiation-response biomarkers. The multi-biomarker approach not only revealed potential candidates for radiation response, but provided additional mechanistic insights into the response in AT-deficient cells.

Allogeneic Hematopoietic Stem Cell Transplantation for a BCR-FGFR1 Myeloproliferative Neoplasm Presenting as Acute Lymphoblastic Leukemia.

Hematopoietic myeloproliferative neoplasms (MPNS) with rearrangements of the receptor tyrosine kinase FGFR1 gene, located on chromosome 8p11, are uncommon and associated with diverse presentations such as atypical chronic myeloid leukemia, acute myeloid leukemia, or an acute T- or B-lymphoblastic leukemia, reflecting the hematopoietic stem cell origin of the disease. A review of MPN patients with the t(8;22) translocation that results in a chimeric BCR-FGFR1 fusion gene reveals that this disease either presents or rapidly transforms into an acute leukemia that is generally unresponsive to currently available chemotherapeutic regimens including tyrosine kinase inhibitors (TKIS). The first case of a rare BCR-FGFR1 MPN presenting in a B-acute lymphoblastic phase who underwent allogeneic hematopoietic stem cell transplantation (HSCT) with a subsequent sustained complete molecular remission is described. Allogeneic HSCT is currently the only available therapy capable of achieving long-term remission in BCR-FGFR1 MPN patients.

Estrogen induces phospholipase A2 activation through ERK1/2 to mobilize intracellular calcium in MCF-7 cells.

The principal secreted estrogen, 17beta-estradiol rapidly activates signaling cascades that regulate important physiological processes including ion transport across membranes, cytosolic pH and cell proliferation. These effects have been extensively studied in the MCF-7 estrogen-responsive human breast carcinoma cell line. Here, we demonstrate that a physiological concentration of 17beta-estradiol caused a rapid, synchronous and transient increase in intracellular calcium concentration in a confluent monolayer of MCF-7 cells 2-3 min after treatment. This response was abolished when cells were pre-incubated with the phospholipase A(2) (PLA(2)) inhibitor quinacrine or with the cyclooxygenase inhibitor indomethacin. The translocation of GFP-cPLA(2)alpha to perinuclear membranes occurred 1-2 min after 17beta-estradiol treatment; this translocation was concurrent with the transient phosphorylation of cPLA(2)alpha at serine residue 505. The phosphorylation and translocation of cPLA(2) were sensitive to inhibition of the extracellular signal regulated kinase (ERK) signaling cascade and occurred simultaneously with a transient activation of ERK. The phosphorylation of cPLA(2) could be stimulated by membrane impermeable 17beta-estradiol conjugated to bovine serum albumen and was blocked by an antagonist of the classical estrogen receptor. Here we show, for the first time, that PLA(2) and the eicosanoid biosynthetic pathway are involved in the 17beta-estradiol induced rapid calcium responses of breast cancer cells.