Treatment of doxorubicin-resistant human myeloid leukemia cells with baicalin results
in decreased expression of Bcl-2, c-myc, procaspase-3, and poly(ADP-ribose) polymerase (PARP), increased expression of Bad and cleaved PARP, and enhanced sensitivity to doxorubicin [8]. The growth of certain types of cultured lymphoma cells has been found to be suppressed by treatment with Scutellaria baicalensis extracts containing 21% baicalin [9]. However, no studies that examine the effects of baicalin on lymphoma cell proliferation have been reported. Tipifarnib manufacturer The phosphatidylinositol-3-kinase (PI3K)/serine/threonine kinase (Akt) signaling pathway is essential to the survival and proliferation of human cells, and constitutive activation of this pathway is thought to play a critical role in the progression of human hematologic malignancies [10, 11]. Inhibitors of this pathway have been shown to induce apoptosis in isolated leukemia, lymphoma, and myeloma cells. The CA46 lymphoma cell line [12], which was 17-AAG mw derived from the ascites fluid of a patient with American-type Burkitt lymphoma, carries
the (8;14) translocation, overexpresses Bcl-2 and c-myc mRNAs, and has been proven a useful model of Burkitt lymphoma. The following NU7441 nmr study was undertaken to ascertain whether baicalin down-regulates the PI3K/Akt signaling pathway in CA46 cells concurrently with induction of apoptotic cell death. Materials and methods Materials Baicalin (C21H18O11, MW 446.35) was purchased from Qingzhe (Nanjing, Jiangsu, China). A 50 mM stock solution was prepared by dissolving 22.3 mg of the drug in 1 ml of dimethyl sulfoxide (DMSO; Sigma, St. Louis, MO, USA). The stock solution was maintained at −20°C and was diluted to appropriate concentrations with culture medium immediately before experimental Selleck Etoposide use. Under these conditions, no baicalin solubility issues were encountered. The highest final concentration of DMSO in baicalin-treated preparations was 0.08%; the viability of control preparations
was unaffected at this DMSO concentration. Cell culture The Jurkat, K562, HL-60, and CA46 Burkitt lymphoma cell lines were obtained from the China Center for Type Culture Collection (CCTCC; Wuhan, Hubei, China). Cultures were maintained in RPMI-1640 medium (Gibco, Grand Island, NY, USA) with 10% fetal bovine serum (FBS; Gibco, Grand Island, NY, USA) at 37°C in a humidified atmosphere containing 5% CO2. Proliferation assay The 3-(4,5-dimethylthiazol-2-yl)-2,5 diphenyltetrazolium bromide (MTT) assay was used to measure the rate of cell proliferation. Briefly, CA46 cells (1 × 104/well) were seeded in 96-well plates and treated with baicalin at varying concentrations. After varying incubation times, cells were treated with 20 μl of MTT solution (Sigma, St.