t(11;18)(q21;q21) has been recognized as a characteristic chromosomal translocation in mucosa‐associated lymphoid tissue (MALT)‐type lymphoma, and recent studies have demonstrated that this ...translocation results in the chimaeric transcript of API2 (apoptosis inhibitor 2)‐MALT1 (mucosa‐associated lymphoid tissue lymphoma translocation gene 1). In this study, we used reverse transcription polymerase chain reaction (RT–PCR) to analyse the incidence of this fusion product in a large series of MALT lymphoma, nodal marginal zone B‐cell lymphoma (nMZBCL) and extranodal diffuse large B‐cell lymphoma (DLBL) cases. RT–PCR analysis revealed that 17 of the 95 (17·9%) MALT lymphomas but none of the nine nMZBCLs or 16 DLBLs had API2‐MALT1 fusion transcripts. The incidence of API2‐MALT1 varied among MALT lymphomas arising from different sites and was highest for pulmonary MALT lymphomas (10 out of 16 cases, 62·5%). The presence of the API2‐MALT1 fusion gene was also confirmed by long and accurate (LA)–PCR with genomic DNA, and the result correlated well with that obtained with the RT–PCR assay, thus demonstrating the usefulness of LA–PCR for the detection of the API2‐MALT1 fusion gene.
We measured the plasma concentrations of 7-ethyl-10-4-(1-piperidino)-1-piperidine carbonyloxycamptothecin (CPT-11) and the active metabolite 7-ethyl-10-hydroxycamptothecin (SN-38), after treatment ...with CPT-11 to rats pretreated with bis-p-nitrophenylphosphate (BNPP) which is a specific inhibitor of carboxylesterase, and non-pretreated rats. The plasma level of SN-38 was decreased in the BNPP-pretreated group compared with these of non-pretreated group, indicating that the esterase involved in CPT-11 metabolism is a carboxylesterase. We also characterized the molecular species of carboxylesterase involved in CPT-11 metabolism using enzyme preparations purified from liver microsomes. Thirteen carboxylesterase isozyme activities towards CPT-11 were compared and guinea pig GLP1 was found to have the highest activity, while human HU1 isozyme had relatively lower activity than those of animal species. In studies on the kinetic parameters of the hydrolysis of CPT-11 by the purified carboxylesterase isozymes the highest Vmax value of the isozymes was found in human HU1 and the smallest was seen in rat RL1. The Vmax/Km for RL1 showed the largest value of 21.7 nmol/mg protein/mM.
The biological function of the SART-1 gene product is demonstrated and its potential as a target for cancer gene therapy is discussed.
The SART-1 gene was transduced by a recombinant adenovirus ...vector and its expression was promoted by a CMV promoter.
The transduction efficiency by recombinant adenoviruses in A549 and MCF-7 cells was determined using a vector expressing luciferase, which showed high expression in the cells. Cell count analysis using Trypan-Blue dye exclusion showed that SART-1 gene transduction inhibited cell growth. Flow cytometry analysis suggested that SART-1 gene transduction induced cell cycle arrest followed by apoptosis. Western blot analysis confirmed that the apoptosis pathway was activated by SART-1 gene transduction.
These results show that SART-1 gene transduction induces cell cycle arrest leading to apoptosis and suggest the possibility of gene therapy against cancer. In addition, SART-1 is known to be a tumor antigen in a range of cancers recognized by T cells, thus a potential strategy would be the combination of suicide gene therapy with immuno-gene therapy.
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