Chemosensitization effects of XIAP downregulation in K562 leukemia cells

The effect of downregulation of the expression of the antiapoptotic protein XIAP with antisense oligonucleotides was evaluated in the K562 chronic myeloid leukemia (CML) cell line. This was carried out by studying the effects of downregulation of XIAP expression on cellular viability, cellular apoptosis and on the response to two chemotherapeutical drugs, etoposide and doxorubicin. We document that downregulation of XIAP expression decreased cellular viability, increased cellular apoptosis and enhanced the effects of doxorubicin.

Comparative analysis of the trypanocidal activity and chemical properties of E-lychnophoric acid and its derivatives using theoretical calculations

E-Lychnophoric acid 1, its derivative ester 2 and alcohol 3 killed 100% of trypomastigote blood forms of Trypanosoma cruzi at the concentrations of 13.86, 5.68, and 6.48 µg/mL, respectively. Conformational distribution calculations (AM1) of 1, 2 and 3 gave minimum energies for the conformers a, b, c, and d, which differ from each other only in the cyclononene ring geometry. Calculations (DFT/BLYP/6-31G*) of geometry optimization and chemical properties were performed for conformers of 1, 2, and 3. The theoretical results were numerically compared to the trypanocidal activity. Calculated values of atomic charge, orbital population, and vibrational frequencies showed that the C-4-C-5 pi-endocyclic bond does not affect the trypanocidal activity of the studied compounds. Nevertheless, the structure of the group at C-4 strongly influences the activity. However, the theoretical results indicated that the intra-ring (C-1 and C-9) and pi-exocycle (C-8 and C-14) carbons of caryophyllene-type structures promote the trypanocidal activity of these compounds.

The PML-RAR alpha transcript in long-term follow-up of acute promyelocytic leukemia patients

BACKGROUND AND OBJECTIVES

Detection of PML-RAR alpha transcripts by RT-PCR is now established as a rapid and sensitive method for diagnosis of acute promyelocytic leukemia (APL). Although the majority of patients in long-term clinical remission are negative by consecutive reverse transcription polymerase chain reaction (RT-PCR) assays, negative tests are still observed in patients who ultimately relapse. Conversion from negative to positive PCR has been observed after consolidation and found to be a much stronger predictor of relapse. This study reports on 47 APL patients to determine the correlation between minimal residual disease (MRD) status and clinical outcome in our cohort of patients.

DESIGN AND METHODS

The presence of PML-RAR alpha t transcripts was investigated in 47 APL patients (37 adults and 10 children) using a semi-nested reverse transcriptase-polymerase chain reaction to evaluate the prognostic value of RT-PCR tests.

RESULTS

All patients achieved complete clinical remission (CCR) following induction treatment with all-trans retinoic acid (ATRA) and chemotherapy (CHT) or ATRA alone. Patients were followed up between 2 and 117.6 months (median: 37 months). Relapses occurred in 11 patients (9 adults and 2 children) between 11.4 and 19 months after diagnosis (median: 15.1 months) while 36 patients (28 adults and 8 children) remained in CCR. Seventy-five percent of patients carried the PML-RAR alpha long isoform (bcr 1/2) which also predominated among the relapsed cases (9 of 11) but did not associate with any adverse outcome (p= 0.37). For the purpose of this analysis, minimal residual disease tests were clustered into four time-intervals: 0-2 months, 3-5 months, 6-9 months and 10-24 months.

INTERPRETATION AND CONCLUSIONS

Children showed persisting disease for longer than adults during the first 2 months of treatment. At 2 months, 10 (50%) of 20 patients who remained in CCR and 4 (80%) of 5 patients who subsequently relapsed were positive. Patients who remained in CCR had repeatedly negative results beyond 5.5 months from diagnosis. A positive MRD test preceded relapse in 3 of 4 tested patients. The ability of a negative test to predict CCR (predictive negative value, PNV) was greater after 6 months (>83%), while the ability of a positive test to predict relapse (predictive positive value, PPV) was most valuable only beyond 10 months (100%). This study (i) highlights the prognostic value of RT-PCR monitoring after treatment of APL patients but only from the end of treatment, (ii) shows an association between conversion to a positive test and relapse and (iii) suggests that PCR assessments should be carried out at 3-month intervals to provide a more accurate prediction of hematologic relapses but only after the end of treatment.

Differences in phenotype, growth factor requirements, pattern of expression of adhesion molecules and rate of apoptosis displayed by three new myeloid sister leukemic cell lines

We established three new human myeloid cell lines from one patient, in the presence of granulocyte-macrophage colony-stimulating factor (UPM1-GM), interleukin-3 (UMP1-IL-3) or without exogenous growth factors (UPM1). The 3 lines were characterized by phenotypic, genotypic and functional studies. These cell lines may provide useful tools to study different aspects of leukemic cell biology

Limited synergistic effect of antisense oligonucleotides against bcr-abl and transferrin receptor mRNA in leukemic cells in culture

The synergistic use of antisense oligonucleotides (ASOs) towards the bcr-abl and the transferrin receptor (TfR) mRNA was studied in a chronic myeloid leukemia (CML) cell line, aiming to improve the efficiency of individual ASO treatment. At 20 microM concentration, bcr-abl ASOs reduced cell growth by 40% and was specific for cells that have the translocation: there was a 34% reduction of BCR-ABL protein. The TfR ASO reduced cell growth by 20% and decreased TfR protein by 24%. The ASOs were more potent at reducing cell growth when used in combination (respectively, -20 and -17% than bcr-abl ASO and TfR ASO when used individually at the 10 microM concentration), thus we postulate that there is synergism of action. Cell cycle analysis also revealed that the sub-G1 peak was bigger in the synergistic treatment.

Configuration of immunoglobulin and T cell receptor beta and gamma genes in acute myeloid leukaemia: pitfalls in the analysis of 40 cases

AIMS

To evaluate the overall incidence of immunoglobulin (Ig) and T cell receptor (TCR) beta and gamma gene rearrangements in a series of 40 cases of acute myeloid leukaemia (AML) and to determine whether structural modifications of these genes could be correlated with the abnormal expression of lymphoid markers in malignant cells.

METHODS

All cases were classified according to the criteria of the FAB group and immunophenotyped with a panel of monoclonal antibodies reactive with myeloid and lymphoid differentiation antigens. DNA analysis was performed by the method of Southern using probes for the Ig JH, TCR-C beta 1, and TCR-J tau 1 regions.

RESULTS

Phenotypic analysis showed that in addition to myeloid markers, 10 cases expressed lymphoid antigens: CD7 in seven (of which three were TdT positive, one CD2 positive, and one CD19 positive) and CD19 in three. Southern blot analysis showed that bands with sizes different from the germ line control were present in the TCR beta genes in 11 cases: in six of 30 with pure myeloid phenotype and in five of 10 of those expressing lymphoid markers. A close observation of the size and patterns of those bands, however, showed that they could be artefactual. Indeed, further analysis showed that they were either due to resistant Eco RI/Hind III sites at the beta locus or to plasmid contamination. Rearranged genes were eventually found in only two of the 40 cases: at the Ig JH region in one of the 30 with pure myeloid phenotype (3.3%) and at the TCR gamma genes in one of 10 with lymphoid markers (10%).

CONCLUSIONS

These observations showed that Ig/TCR gene rearrangements were rare in this AML series (overall incidence of 5%) and that they were not significantly more common in cases with aberrant expression of lymphoid markers. The size and pattern of the potential non-germline bands that can be found in these loci must be carefully evaluated.

[Molluscacide activity of a mixture of 6-n-alkyl salicylic acids (anacardic acid) and 2 of its complexes with copper (II) and lead (II)]

The molluscicide activity of hexanic extract from Anacardium occidentale L. (cashew) nut shell, of copper (II) complex, of lead (II) complex and anacardic acid has been compared in the laboratory in an attempt to obtain better stability than anacardic acid. This was obtained from the hexanic extract of the cashew nut shell by precipitation with lead (II) hydroxide or cupric sulfate plus sodium hydroxide or (II) cupric hydroxide followed by treatment of lead (II) complex with a diluted solution of sulfuric acid. Ten products of the mixture obtained were tested on adults snails of Biomphalaria glabrata at 1 to 10 ppm. The most active products were copper (II) complex, obtained by cupric sulfate plus sodium hydroxide, and anacardic acid (sodium hydroxide) which presented activity at 4 ppm. The anacardic acid's lead content was above the limits accepted by the United States standards.