Spleen Tyrosine Kinase Inhibitor TAK-659 Prevents Splenomegaly and Tumor Development in a Murine Model of Epstein-Barr Virus-Associated Lymphoma.

Epstein-Barr virus (EBV) is associated with several B and epithelial cell cancers. EBV-encoded latent membrane protein 2A (LMP2A) contributes to cellular transformation by mimicking B cell receptor signaling. LMP2A/MYC double transgenic mice develop splenomegaly and B cell lymphoma much faster than MYC transgenic mice do. In this study, we explored the potential therapeutic efficacy of a novel spleen tyrosine kinase (SYK) and FLT3 inhibitor TAK-659 for development of a treatment option for EBV-associated malignancies. In our transgenic model, TAK-659 treatment totally abrogated splenomegaly and tumor development in LMP2A/MYC mice in both pretumor and tumor cell transfer experiments. TAK-659 treatment killed tumor cells, but not host cells within the spleen and tumors. Furthermore, TAK-659 treatment abrogated metastasis of tumor cells into bone marrow. Our data also show that TAK-659 inhibits SYK phosphorylation and induces apoptosis in LMP2A/MYC tumor cells at low nanomolar concentrations. Therefore, TAK-659 may provide an effective therapeutic option for treatment of LMP2A-positive EBV-associated malignancies and should be explored further in clinical trials.IMPORTANCE The novel SYK and FLT3 inhibitor TAK-659 prevents the enlargement of spleen and tumor development in a mouse model of EBV-associated lymphoma by counteracting the activation of cellular kinase SYK through the viral LMP2A gene by inducing cell death in tumor cells but not in nontumor cells. These findings indicate that TAK-659 may be a very effective nontoxic therapeutic molecule especially for EBV-positive hematologic malignancies.

Roles of Signal Transducer Pathways in Investigation of Biopsies from Patients with Bladder Tumors

Background:The process of development of bladder cancer features alteration of normal biological conditions caused by changes in molecular pathways. Removing control over regulation of these pathways could lead to changes in signal transduction and abnormal regulation of genes. During tumor formation and progression, genes regulate critical cellular processes, involved in cell cycling, growth and death. Here we evaluated the expression and prognostic importance of FGFR1, HRAS, CCND1, CCND3, STAT3 and FAS genes. Methods: Tumor tissues of 44 patients diagnosed with bladder cancer were investigated for changes in expression levels of FGFR1, HRAS, CCND1, CCND3, FAS and STAT3 genes by the RT-PCR method. Signal transduction pathways and expression of individual genes related to these pathways were analyzed using the "One Sample Test". Results: There were statistically significant changes in the expression levels of HRAS, CCND1, CCND3 and STAT3, but not FGFR1 and FAS genes. Examination of associations with age, gender, smoking, chemotherapy, tumor grade and tumor growth pattern using the "Independent Samples Test", showed importance relations between the CCND1 gene and cigarette smoking and sex. Conclusion: Over-expression of HRAS, CCND1, CCND3 and STAT3 genes may play roles in bladder cancer development and progression, while cigarette smoking is significantly associated with CCND1 gene expression and consequently concluded to be contributing to the development of bladder cancer.

Comparison of the cytogenetic and molecular analyses in the assessment of imatinib response in chronic myelocytic leukemia.

We aimed to compare the cytogenetic and molecular analyses in the assessment of imatinib mesylate response in patients suffering the chronic phase of chronic myelocytic leukemia who were refractory to alpha-interferon treatment. A total of 117 patients in the chronic phase of chronic myelocytic leukemia were included. The patients were treated with 400 mg/day imatinib mesylate. Bone marrow samples were obtained for the cytogenetic and molecular analyses. Patients without the Ph chromosome were defined as complete cytogenetic responders. Partial cytogenetic response was determined when the Ph chromosome was detected in 1-35% of the cells. Molecular response was determined by quantitative real-time reverse transcriptase polymerase chain reaction (QR-PCR) and defined as no detection of BCR-ABL mRNA. The frequencies of complete and partial cytogenetic response were 29% (n = 34) and 15% (n = 18), respectively. No cytogenetic response was achieved in 56% (n = 65) of the patients. Molecular response was achieved in 62% (n = 21) and 33% (n = 6) of the complete and partial cytogenetic responders, respectively. All of the 65 patients with no cytogenetic response were also molecular nonresponders. We conclude that there is reasonable agreement between the cytogenetic and molecular analyses. Both methods are complementary in the assessment of response to therapy.

Increased sister chromatid exchange frequency in young women with breast cancer and in their first-degree relatives.

The well-known increased risk of breast cancer (BC) in first-degree relatives of patients with BC has been related to shared genetic factors including defective DNA repair, with loss of genomic integrity. On the other hand, it can be hypothesized that early-onset breast cancer is also associated with overburden of heritable factors leading to increased DNA injury. In this respect, we analyzed sister chromatid exchange frequency (SCE) in 20 women with breast cancer (all < or =40 years old), in their first-degree female relatives, and in 20 age-matched healthy females without a personal or family history of cancer. SCE was significantly increased (P < 0.05) in patients (7.17 +/- 1.81 per metaphase) and in their first-degree relatives (6.44 +/- 0.98), compared with controls (5.85 +/- 0.72). There was no difference in SCE frequency between patients and their first-degree relatives. We suggest that the increased SCE in patients reflects a genomic instability that may be operative in carcinogenesis. Further, genomic instability is shared also by first-degree relatives, although none of them had a history of breast cancer at the time of the study.

Myeloid/natural killer cell precursor acute leukemia with tetraploidy.

Myeloid/natural killer (NK) cell precursor acute leukemia is characterized by coexpression of myeloid and natural killer cell antigens and an aggressive clinical course. Here we report a case of myeloid/NK precursor acute leukemia in a 37-year-old woman. Clinical presentation was correlated with leukemic blast morphology, immunophenotype, and cytogenetic analysis. The patient had noted fever, weakness, purpura, peripheral lymphadenopathy, and moderate hepatosplenomegaly. Peripheral blood smears and bone marrow aspirate smears at presentation revealed blastic cells, which were generally L2 shaped, with variation in cell size, round to moderately irregular nuclei and prominent nucleoli, pale cytoplasm, and a lack of azurophilic granules. Immunophenotypic analysis of the blasts displayed coexpression of myeloid and natural killer cell antigens with relatively immature phenotype: CD7+, CD33+, CD34+, CD56+, CD57+, CD16-, MPO-. Cytogenetic analysis of marrow cells showed 62% of cells with a normal female karyotype; in the remaining 38%, tetraploid changes were detected, where the chromosome number was 92, with no preferential losses or gains of chromosomes. Fluorescence in situ hybridization analysis revealed the same abnormality. The patient did not respond to chemotherapy (cytosine arabinoside and idarubicin) and died of a septic complication on the 34th day after admission. To our knowledge, this is the first description of tetraploidy in myeloid/NK cell precursor acute leukemia.

Genotoxicity and sister chromatid exchange in patients with myelodysplastic disorders.

In this study, we aimed to evaluate genotoxicity by sister chromatid exchange frequency in the peripheral lymphocytes of patients with myelodysplastic syndrome (MDS). The study population consisted of 16 patients (females/males:6/10; mean age: 61.68 +/- 13.08 years) diagnosed with "refractory anemia" according to FAB classification. The results were compared with an age- and sex-matched control group. The sister chromatid exchange frequency in the study group was found to be significantly higher than the control group (8.3 +/- 11 vs. 6.83 +/- 1.07, P=0.0046). We suggest that increased DNA damage, which is revealed by the increased sister chromatid exchange in the present study may play a role in the etiopathogenesis of MDS.

Sister chromatid exchange and mitotic index in patients with cirrhosis related to hepatitis B and C viruses and in chronic carriers.

BACKGROUND/AIMS: It is controversial whether hepatitis B or C viruses induce liver cancer through non-specific mechanisms (inflammation and cell renewal) or direct genotoxicity. Considering that both viruses infect peripheral lymphocytes, studying sister chromatid exchange frequency and mitotic index in peripheral lymphocytes is a reasonable experimental approach to investigate their genotoxic potential separately. In the present study we investigated sister chromatid exchange frequency and mitotic index in the peripheral lymphocytes of patients with cirrhosis and chronic carriers with positive serology for HBV or HCV infections. METHODOLOGY: The study population consisted of 3 groups: group I involved 23 HBsAg positive chronic carriers; group II involved 30 HBsAg positive patients with cirrhosis and group III involved 9 HCV-positive patients with cirrhosis. The control group involved 30 healthy individuals. RESULTS: Sister chromatid exchange frequency was significantly higher in all the study groups than the control group (p < 0.05). The mitotic index was significantly lower in all the study groups than the control group (p < 0.05). CONCLUSIONS: The increased sister chromatid exchange frequency and low mitotic index may be reflecting a direct genotoxic effect of HBV and HCV in peripheral lymphocytes. We suggest that the same genotoxicity may also operate in the liver and contribute to hepatocarcinogenesis.