Combined antileukemic activity of pIXY 321 and ara-c against human acute myeloid leukemia cells

Caroline Tang, Yue Huang, Vidya S. Ponnathpur, Swapan Ray, Mary Ella Mahoney, Gloria Bullock, Ana Maria Ibrado, Kapil Bhalla

Research output: Contribution to journalArticlepeer-review

2 Scopus citations


Prolonged administration of conventional (100 mg/m2/day) or low dose Ara-C (20 mg/m2/day) has been associated with significant clinical antileukemic effects in AML and myelo-dysplastic syndromes. These doses and schedules of Ara-C yield plasma Ara-C concentrations in the range of 10 to 100 nM. Utilizing concentrations and a schedule of Ara-C treatment, representative of Ara-C exposures in these clinical situations, we performed in vitro studies to examine the effects of co-treatment with pIXY 321 on Ara-C induced apoptosis and Ara-C-mediated colony growth inhibition of human myeloid leukemia HL-60 cells. Significantly greater internucleosomal DNA fragmentation, higher percentage of morphologically recognizable apoptotic cells and increased colony growth inhibition were observed following treatment with 100 versus 10 nM Ara-C for 5 days. Simultaneous exposure to 10 ng/ml pIXY 321 resulted in significantly increased colony growth inhibition as well as DNA fragmentation and apoptosis due to 10 nM but not 100 nM Ara-C. These concentrations of Ara-C inhibited c-myc and did not induce c-jun mRNA expression. These effects of Ara-C on c-myc and c-jun expressions were not influenced by co-treatment with pIXY 321. Neither treatment with pIXY 321 or Ara-C alone, nor co-treatment with pIXY 321 and Ara-C, significantly altered the intracellular p26BCL-2 levels in HL-60 cells. These results indicate that co-treatment with pIXY 321 significantly increases low dose Ara-C-induced apoptosis and thereby its antileukemic activity.

Original languageEnglish (US)
Pages (from-to)445-451
Number of pages7
JournalLeukemia and Lymphoma
Issue number5-6
StatePublished - 1994


  • Apoptosis
  • bcl-2 gene
  • HL-60 cells
  • Low-dose Ara-C
  • pIXY 321

ASJC Scopus subject areas

  • Cancer Research
  • Hematology
  • Oncology


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