MDR1 mediated drug resistance is one of the main problems for some cancer chemotherapies. Vincristine (VCR) is an effective drug used in clinical treatment of acute leukemias. The concentration of VCR was stepwise increased (1-50 nM) in the cell culture media of HL60 cells (AML cell line). The viability of cells was determined and the expression of MDR1 gene was studied by using reverse transcr...

2F-Adenine arabinoside (fludarabine, Fara-A) and 2-chloro-2'-deoxyadenosine (cladribine, CdA) are nucleoside analogues with antineoplastic activity in vitro and in vivo. Lack of clinical resistance between CdA and Fara-A has been demonstrated in patients with chronic lymphocytic leukemia (G. Juliusson et al., N. Engl. J. Med., 327: 1056-1061, 1992). To clarify the differences in mechanism of re...

Sanguinarine, a plant alkaloid, was identified as a potent and specific protein phosphatase (PP) 2C inhibitor. It inhibited PP2C competitively with respect to alpha-casein (Ki=0.68 microM) and showed selectivity for PP2C as compared with PP1, PP2A, and PP2B in vitro. In vivo, sanguinarine showed cytotoxicity toward human promyelocytic leukemia cell line HL60, with an IC(50) value of 0.37 microM...

A novel antibiotic tautomycin induced many blebs on the surface of K562 human chronic myeloid leukemia cells, similar to the morphological changes induced by phorbol esters. However, tautomycin did not induce nitroblue tetrazolium reducing activity, when HL60 human promyelocytic leukemia cells were caused to differentiate by quinomycin into mature granulocytes. It did not induce spread of HL60 ...

Etoposide (VP-16) is extensively used to treat cancer, yet its efficacy is calamitously associated with an increased risk of secondary acute myelogenous leukemia. The mechanisms for the extremely high susceptibility of myeloid stem cells to the leukemogenic effects of etoposide have not been elucidated. We propose a mechanism to account for the etoposide-induced secondary acute myelogenous leuk...

A series of tetrandrine derivatives were designed and synthesized using Suzuki coupling reaction. Eleven targeted compounds with over 50% inhibition against HL60 and A549 human cancer cell lines at 10 μM were further evaluated for the in vitro antitumor activities by MTT or SRB assay. The biological results revealed that some compounds exhibited potent antitumor activities. Thiophene derivative...