We previously reported that MX2, a new morpholino anthracycline, showed marked effects on pleiotropic drug-resistant sublines of murine P388 leukemia in vivo as well as in vitro. In this study we examine the in vitro cytotoxicity against pleiotropic drug-resistant sublines of human tumor cell lines. MX2 was effective against multidrug-resistant sublines of four human tumor cell lines; these cel...

We examined the antileukemic effects of high concentrations of L-ascorbic acid (high AA) on human leukemic cells. In vitro, high AA markedly induced apoptosis in various leukemic cell lines by generating hydrogen peroxide (H2O2) but not in normal hematopoietic stem/progenitor cells. High AA significantly repressed leukemic cell proliferation as well as neoangiogenesis in immunodeficient mice. W...

K562-R, a pleiotropic drug-resistant cell line established in vitro, and K562-S, the chemotherapy-sensitive parent line, were used as targets in the natural killer cell (NK) system. At each of the effectortarget ratios studied, the K562-R demonstrated a decrease in their susceptibility to both unstimulated and interferon-activated NK cells, as compared to the K562-S line. This difference did no...

Basic fibroblast growth factor (bFGF) and transforming growth factor-beta 1 (TGF-beta) have both been shown to act on hematopoietic progenitor cells. bFGF is a hematopoietic cytokine that acts on progenitor cells in concert with other cytokines to promote their proliferation. TGF-beta induces erythroid differentiation in K562 cells. To determine whether bFGF might act on progenitor cells by ant...

The tumor-promoting phorbol ester, 12-O-tetradecanoylphorbol-13-acetate (TPA), induced specific changes in the cell surface glycoprotein profile of K562 human leukemic cells. TPA-treated K562 cells were examined by cell surface labeling followed by immunoprecipitation with anti-glycophorin antiserum or anti-K562 antiserum. TPA-treated K562 cells lost glycophorin and glycoprotein with a molecula...

Protein tyrosine phosphatase 1B (PTP1B) is a negative regulator of BCR-ABL-mediated transformation in vitro and in vivo. To investigate whether PTP1B modulates the biological effects of the abl kinase inhibitor STI571 in BCR-ABL-positive cells, we transfected Philadelphia chromosome-positive (Ph+) chronic myeloid leukemia cell-derived K562 cells with either wild-type PTP1B (K562/PTP1B), a subst...

Today, development of resistance to anticancer drugs (including cisplatin) is noticed as a major problem. Recently several studies demonstrated that palladium complexes showed remarkable cytotoxic effects against K562 cell line and could be used efficiently for treatment of many human cancers including leukemia. Hereof, K562 cells were made resistant to cisplatin using increasing concentration ...

Nilotinib, a second-generation tyrosine kinase inhibitor (TKI), has been approved for first-line chronic myeloid leukemia (CML) treatment. The improved clinical response of nilotinib over that of the first generation TKI, imatinib, has been thought to be a result of its high potency of inhibition of BCR-ABL kinase. This study aimed to characterize differences between nilotinib and imatinib in t...