| Co-Investigator(Kenkyū-buntansha) |
TOBITA Tadasu Hamamatsu University School of Medicine, Senior Resident, 医学部附属病院, 医員
TAKESHITA Akihito Hamamatsu University School of Medicine, Research Associate, 医学部附属病院, 助手 (00242769)
OHNO Ryuzo Hamamatsu University School of Medicine, Professor, 医学部, 教授 (70093002)
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| Budget Amount *help |
¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 1996: ¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 1995: ¥1,800,000 (Direct Cost: ¥1,800,000)
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| Research Abstract |
Homeobox genes (HOX) may have a regulatory function in the differentiation process of hematopoiesis. We examined the change of HOX B6 and HOX B9 mRNA expressions during the in vitro differentiation of four myeloid leukemia cell lines because HOX B6 may be involved closely in myeloid differentiation. NKM-1, HL-60, NB4, and NOMO-1 were established from acute leudemia of M2, M2, M3, and M5 subtype of the French-American-British classification, respectively. All-trans retinoic acid (ATRA), TPA,and G-CSF were used as differentiation inducers. Each cell line was wltured with each inducer and total RNA was isolated on day 1,2,3, or 5. HOX B mRNA was detected by Northem blotting and RT-PCR methods. HOX B6 and HOX B9 mRNAs were constitutively expressed in NKM-1, NB4, and NOMO-1, but were expressed at very low levels in HL-60, HOX B6 and HOX B9 mRNAs were also expressed in fresh acute myelocytic leukemia blasts. HOX B6 mRNA expression in HL-60, NKM-1, and NB4 cultured with ATRA increased on day
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3 and decreased on day 5. HOX B6 mRNA expression in NKM-1 and NB4 cultured with TPA decreased on day 3. HOX B9 mRNA expression displayd changes similar to those of HOX B6 mRNA in NKM-1 and NB4. These results indicate that myeloid leukemia cell lines express HOX B6 and HOX B9, and that their respective mRNA expressions increase at an early stage of myeloid differentiation and then decrease during a late stage. HOX B6 mRNA expression decreased in NKM-1 which showed monocytoid differentiation by TPA induction. HOX B6 antisense-oligonucleotide inhibited the proliferation of NKM-1 and NB4, and it clearly did inhibit the proliferation of NKM-1, NB4, and HL-60 when stimulated with G-CSF.These results suggest that HOX B gene expression is related to simultaneous activation of cellular proliferation and differentiation, and that the aberrant expression may result in transcriptional regression of the genetic program of differentiation, and that HOX B gene expression plays a role in leukemogenesis. Less
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