Assessment of the cellular response to the induced expression of defensin sense and antisense cDNA in acute promyelocytic leukemia cell lines.
Defensins are 20-30 amino acid-long, cystine- and arginine-rich peptides that constitute more than 5% of the total cellular proteins in mature granulocytes and at least 30% of proteins in primary granules. Human defensins were reported to have antimicrobial, antifungal, antiviral and tumor lysis activities. Defensin mRNA was isolated using the differential display technique from the well-characterized all-trans retinoic acid (ATRA)-responsive acute promyelocytic leukemia cell line, NB4. The differential display analysis showed an up-regulation of defensin mRNA in NB4 cells after treatment with 10(-7) M ATRA for 24 h. This expression was not seen in an NB4:R2 cell line, an ATRA-resistant subclone of NB4 cells. In order to investigate further the effects of this gene on our cellular model, we virally infected our cells with full-length defensin cDNA in the sense and antisense directions. Sense defensin induced cell growth arrest and cell death in both cell lines. While NB4 cells died within 48-73 h, NB4:R2 cells survived for 96 h before dying in culture. Phenotypic analysis showed high expression of Annexin V in sense-infected cells compared with antisense and uninfected cells in both cell lines. There was not a significant increase in CD11b expression in any of the 2 cell lines used. No cellular response was encountered in antisense-infected cells. Our data suggest that defensin is not only a reliable marker for granulocytic differentiation, but can also be considered a candidate target for molecular therapy in acute promyelocytic leukemia.
Al-Awadhi
Anwaar
A
Department of Haematology, Wales College of Medicine, Biology, Life and Health Sciences, Cardiff University, Cardiff, UK.
Mills
Ken
K
D017304:Annexin A5 / Q000096:biosynthesis; D000970:Antineoplastic Agents / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects / Q000235:genetics; D001483:Base Sequence; D015152:Blotting, Northern; D039481:CD11b Antigen / Q000096:biosynthesis; D002454:Cell Differentiation / Q000187:drug effects / Q000235:genetics; D045744:Cell Line, Tumor; D016373:DNA, Antisense / Q000235:genetics*; D018076:DNA, Complementary / Q000235:genetics*; D004273:DNA, Neoplasm / Q000235:genetics / Q000378:metabolism; D023082:Defensins / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000235:genetics*; D020869:Gene Expression Profiling; D006801:Humans; D015473:Leukemia, Promyelocytic, Acute / Q000235:genetics* / Q000378:metabolism / Q000473:pathology / Q000628:therapy; D008969:Molecular Sequence Data; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014162:Transfection; D014212:Tretinoin / Q000494:pharmacology
D017304:Annexin A5; D000970:Antineoplastic Agents; D039481:CD11b Antigen; D016373:DNA, Antisense; D018076:DNA, Complementary; D004273:DNA, Neoplasm; D023082:Defensins; D014212:Tretinoin