The vitamin E derivative (þ)a-tocopheryl succinate (a-TOS) exerts pro-apoptotic effects in a wide range of tumors and is well tolerated by normal tissues. Previous studies point to a mitochondrial involvement in the action mechanism; however, the early steps have not been fully elucidated. In a model of acute promyelocytic leukemia (APL) derived from hCG-PML-RARa transgenic mice, we demonstrated that a-TOS is as effective as arsenic trioxide or all-trans retinoic acid, the current gold standards of therapy. We also demonstrated that a-TOS induces an early dissipation of the mitochondrial membrane potential in APL cells and studies with isolated mitochondria revealed that this action may result from the inhibition of mitochondrial respiratory chain complex I. Moreover, a-TOS promoted accumulation of reactive oxygen species hours before mitochondrial cytochrome c release and caspases activation. Therefore, an in vivo antileukemic action and a novel mitochondrial target were revealed for a-TOS, as well as mitochondrial respiratory complex I was highlighted as potential target for anticancer therapy.

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A total of 162 rotavirus strains detected between 1996 and 2006 among individuals with diarrhea in Rio de Janeiro, Brazil, were analyzed by multiple-gene genotyping. Characterization of strains was done by RT-PCR assay for amplification and typing of the VP7-, VP4-, VP6-, and NSP4-encoding genes. Overall, 139 (85.8%) strains belonged to the common group A rotavirus combinations: 67 (41.4%) belonged to genotype G1-P[8]-I1-E1; 18 (11.1%) were G2-P[4]-I2-E2; 11 (6.8%) were G3-P[8]-I1-E1; 12 (7.4%) were G4-P[8]-I1-E1; and 31 (19.1%) were G9-P[8]-I1-E1. Two samples presented mixed genotypes (G1 + G3-P[8]-I1-E1 and G1 + G9-P[9]-I1-E1) and rare combinations, such as G2-P[6]-I2-E2 and G9-P[6]-I2-E2, were detected in six (3.7%) strains. The results suggest a linkage among all four genes. Genotypes G1/G3/G4/G5/G9-P[8] were correlated strongly to I1-E1 genotypes and G2-P[4]/P[6] were correlated to I2-E2 genotypes. Unusual combinations of genes, such as G3-P[9]-I2-E2, G9-P[9]-I1-E2, and G3-P[9]-I3-E3, were observed in 15 (9.3%) strains. The characterization of multiple genes allows a more complete analysis of the rotavirus isolates and provides evidence of natural reassortment of strains.

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The aims of this study were to compare the detection of human herpesviruses (HHVs) in the saliva of HIV-infected and healthy control children, and to evaluate associations between viral infection and gingivitis and immunodeficiency. Saliva samples were collected from 48 HIV-infected and 48 healthy control children. Clinical and laboratory data were collected during dental visits and from medical records. A trained dentist determined gingival indices and extension of gingivitis. Saliva samples were tested for herpes simplex virus types 1 and 2 (HSV-1 and HSV-2), varicella zoster virus (VZV), Epstein-Barr virus (EBV), and cytomegalovirus (CMV) by nested polymerase chain reaction assays. Thirty-five HIV-infected and 16 control children had gingivitis. Seventeen (35.4%) HIV-infected children and 13 (27%) control children were positive for HHVs. CMV was the most commonly detected HHV in both groups (HIV-infected, 25%; control, 12.5%), followed by HSV-1 (6.2% in both groups) and HSV-2 (HIV-infected, 4.2%; control, 8.3%). The presence of HHVs in saliva was not associated with the presence of gingivitis in HIV-1-infected children (p = 0.104) or healthy control children (p = 0.251), or with immunosuppression in HIV-infected individuals (p = 0.447). Gingivitis was correlated with HIV infection (p = 0.0001). These results suggest that asymptomatic salivary detection of HHVs is common in HIV-infected and healthy children, and that it is not associated with gingivitis.

Acute promyelocytic leukemia (APL) is characterized by the expansion of blasts that resemble morphologically promyelocytes and harbor a chromosomal translocation involving the retinoic acid receptor α (RARα) and the promyelocytic leukemia (PML) genes on chromosomes 17 and 15, respectively. The expression of the PML/ RARα fusion gene is essential for APL genesis. In fact, transgenic mice (TM) expressing PML/RARα develop a form of leukemia that mimics the hematological findings of human APL. Leukemia is diagnosed after a long latency (approximately 12 months) during which no hematological abnormality is detected in peripheral blood (pre-leukemic phase). In humans, immunophenotypic analysis of APL blasts revealed distinct features; however, the precise immunophenotype of leukemic cells in the TM model has not been established. Our aim was to characterize the expression of myeloid antigens by leukemic cells from hCG-PML/RARα TM. In this study, TM (N = 12) developed leukemia at the mean age of 13.1 months. Morphological analysis of bone marrow revealed an increase of the percentage of immature myeloid cells in leukemic TM compared to pre-leukemic TM and wild-type controls (48.63 ± 16.68, 10.83 ± 8.11, 7.4 ± 5.46%, respectively; P < 0.05). Flow cytometry analysis of bone marrow and spleen from leukemic TM identified the asynchronous co-expression of CD34, CD117, and CD11b. This abnormal phenotype was rarely detected prior to the diagnosis of leukemia and was present at similar frequencies in hematologically normal TM and wild-type controls of different ages. The present results demonstrate that, similarly to human APL, leukemic cells from hCG-PML/RARα TM present a specific immunophenotype.

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As2O3 has been successfully been employed in the treatment of patients with acute promyelocytic leukemia (APL), however it is unavailable to most APL patients in Latin America, and the lack of alternative treatments lead to a very poor prognosis of relapsed/ATRA resistant patients. Here we investigate the anti-leukemic effect of alpha tocopherol succinate (VES) (a vitamin E analog with antiproliferative activity against several cancer cell types) which was shown to activate the intrinsic cell death mediators of caspase-9 and -3 by both its strong redox activity and inhibition of protein kinase C (PKC) and target Akt and JNK pathways. We used a syngenic transplantation model of APL: blasts from hCG-PML/RARalpha transgenic mice (TM) were IV injected in irradiated non-transgenic littermates. Massive infiltration of bone marrow (BM), spleen and liver was detected by 21st day post transplant. Recipient mice were treated with: VES (50UI/g/d) (n=15), As2O3 (2.5μg/g/d) (n=15), VES + As2O3 (n= 15) at the same doses, or vehicle (Control; n=15) starting from Day 4 for 21 days. Molecular remission was determined by RT-PCR for PML/RARalpha. The mean survival time in the Control group was of only 25,6 days (95% C.I. = 20,9 – 30,3), whereas in the VES it was 160,40 (95%CI = 134,2 – 185,6); in the As2O3 of 162,1 (95% CI = 137,97 −186,3) and in the VES+ As2O3 of 163 (95% CI = 139,93 – 186,1). Compared to controls, all treatments significantly prolonged survival. Molecular remission was attained in 86,5% of mice in the VES arm, 80% in the As2O3, and 86,5% in VES + As2O3. No significant organ toxicity was found by histopathological analyses. Another group of twelve recipients was treated with VES or DMSO for 6 days, and the percentage of apoptotic CD117+ leukemic cells in spleen and liver was determined by flow cytometry. Differentiation was evaluated morphologically on Leishman stained BM cytospin preparations after 72h of treatment with VES. The mean percentage of CD117+ apoptotic cells in VES treated mice was significantly higher (41,17 ± 5 versus 62,11 ± 4%, in spleen p<0,03; and 94,65 ± 1% versus 12,94 ± 11,95%, in liver, p<0,01). No significant difference in the number of mature granulocytic cells was detected. Furthermore, we compared the gene expression profile of BM cells obtained from leukemic mice treated with VES or DMSO (n=6, per group) using nylon microarrays representing 598 genes. Data mining from our microarray results revealed the higher expression of Mitogen Activated Protein Kinase 3, Protein Kinase C delta and BCL2 antagonist Killer-1 genes in VES treated samples. These were confirmed by Real Time-PCR. In conclusion, our results demonstrate that VES induces prolonged remissions and that it activates of MAPK and PKC signaling pathways leading to apoptosis.