The chemical constituents from Cephalotaxus lanceolata were isolated and purified by using multiple chromatographic techniques, including octadecylsilane(ODS), silica gel, Sephadex LH-20 column chromatography, and semi-preparative high-performance liquid chromatography(HPLC). A total of 17 compounds obtained were identified by using spectroscopic methods such as nuclear magnetic resonance(NMR), mass spectrometry(MS), and ultraviolet(UV) combined with literature data. Compound 1 was a new alkaloid dimer, named cephalancetine E. The known compounds were determined as cephalancetine A(2), 11-hydroxycephalotaxine(3), 4-hydroxycephalotaxine(4), cephalotaxine(5), epicephalotaxine(6), cephalotaxine β-N-oxide(7), acetylcephalotaxine(8), cephalotine A(9), cephalotine B(10), 11-hydroxycephalotaxine hemiketal(11), 3-deoxy-3,11-epoxy-cephalotaxine(12), cephalotaxinone(13), isocephalotaxinone(14), 2,11-epoxy-1,2-dihydro-8-oxo-cephalotaxine(15), cephalotaxamide(16), and drupacine(17), respectively. Compounds 11, 12, and 15 were isolated from the Cephalotaxus genus for the first time. The biological activity was tested for compounds 1-17. The results reveal that compound 17 displays potent inhibitory activities against three human cancer cell lines(HepG-2, MCF-7, and SH-SY5Y).
Cephalotaxus/chemistry* ; Humans ; Cell Line, Tumor ; Drugs, Chinese Herbal/pharmacology* ; Harringtonines/pharmacology* ; Molecular Structure ; Dimerization ; Alkaloids/isolation & purification* ; Magnetic Resonance Spectroscopy

OBJECTIVETo explore the effects of BTZ plus HHT on proliferation and apoptosis of K562 cells, and to clarify the relationship between the mechanism inderlying the effect of BTZ plus HHT on K562 cells and BCL-2, BAX, MCL-1 proteins.

METHODSThe K562 cells were divided into 4 groups by different treatment: BTZ(20 nmol/L), HHT(40 ng/ml), BTZ(20 nmol/L)+HHT(40 ng/ml) and control. The proliferation inhibition rates of K562 cells in each group were detected by using MTT, and the early apoptosis rates of K562 cells in each group were assayed by using flow cytometry with Annexin V-FITC/PI staining. The proteins level of BCL-2, BAX and MCL-1 in each group were examined by using Western blot.

RESULTSThe inhibition rate of K562 cell proliferation in combined group was higher than that in BTZ, HHT alone group(P<0.01). The early apoptosis rate of K562 cells in combined group was increased significantly in comparison with BTZ and HHT alone group(P<0.05). The BCL-2 protein level of K562 cells in combined group was significantly lower than that in BTZ and HHT alone group(P<0.05). BAX protein level of K562 cells in combined group was higher than that in BTZ and HHT alone group(P<0.05). The Orders of the MCL-1 protein level of K562 cells in 4 groups were BTZ>Control>BTZ plus HHT>HHT(P<0.05 ).

CONCLUSIONThe combination of BTZ and HHT exerts the synergistic effect of anti-proliferative activity and induces apoptosis against K562 cells in vitro. The combination can induce apoptosis of K562 cells via suppression of BCL-2 protein and up-regulation of BAX protein. HHT can increase the sensitivity of K562 cells to BTZ by down-regulating the expression of MCL-1 protein.

Apoptosis ; Bortezomib ; pharmacology ; Cell Proliferation ; Harringtonines ; pharmacology ; Homoharringtonine ; Humans ; K562 Cells

This study was aimed to explore the change of K562 cell apoptosis at different time point after homoharringtonine (HHT) treatment and its mechanism. After treatment of K562 cells with 10 ng/ml HHT, the cell viability was tested with MTT assay; the expression of caspase-3 was detected with Western blot; the BCL-2 expression was analyzed with flow cytometry; the autophagosome was observed by electron microscopy. The results showed that the viability of K562 cells reduced gradually from day 1 to day 5 and ascended from day 6 to day 8 after HHT treatment. At the same time, the cleaved caspase-3 expression level of K562 cells increased gradually from day 1 to day 7, but reduced at the day 8 (P < 0.05). From day 1 to day 8 after HHT treatment, the BCL-2 expression level declined firstly and then went up (P < 0.05). Autophagosome was also seen remarkably at day 8 after HHT treatment. It is concluded that the apoptosis level of K562 cells after being treated with HHT enhances firstly and then declines , which may be associated with higher autophagy level in the late stage of HHT treatment.
Apoptosis ; drug effects ; Autophagy ; Caspase 3 ; metabolism ; Cell Proliferation ; drug effects ; Flow Cytometry ; Harringtonines ; pharmacology ; Humans ; K562 Cells ; Proto-Oncogene Proteins c-bcl-2 ; metabolism

This study was aimed to investigate the effect of homoharringtonine (HHT) on K562 cell proliferation, apoptosis and expression of BCL-2 and NF-κB proteins. The cells proliferation was assayed with MTT method, the cell apoptosis, cell cycle and BCL-2 expression were analyzed with flow cytometry, NF-κB protein expression was detected with Western blot. The results showed that HHT concentration-dependently inhibited proliferation of K562 cells, the IC50 at 48 h was 43.89 ng/ml. Treated with HHT 10 ng/ml for 48 h, K562 cell apoptosis significantly increased, cell cycle was blocked at G0/G1, the expression level of BCL-2 and NF-κB proteins was lower than that in control group (P < 0.05). It is concluded that HHT may inhibit the proliferation of K562 cells, and down-regulating expression levels of BCL-2 and NF-κB may be one of its anti-CML mechanisms.
Flow Cytometry ; Harringtonines ; pharmacology ; Humans ; K562 Cells ; NF-kappa B ; metabolism ; Proto-Oncogene Proteins c-bcl-2 ; metabolism

OBJECTIVETo clarify the effects and mechanisms of homoharringtonine (HHT) monomer therapy or combination therapy with arsenic trioxide (ATO) on human multiple myeloma (MM) cell line RPMI 8226 in in vitro researches.

METHODSEffects of HHT, ATO, and HHT combined ATO on the growth of MM cell line RPMI 8226 were detected using MTT assay. The morphological changes of cell apoptosis were detected by Hoechst staining. The early apoptosis rate was detected using flow cytometry. Expressions of Caspase-3, Caspase-9, poly-ADP-ribose polymerase (PARP), Bcl-2, Mcl-1, Bcl-xl, and AKT protein were detected by Western blot.

RESULTSHHT and ATO inhibited the proliferation of RPM1 8226 cell line in a time- and dose-dependent manner (P < 0.05). Synergistic effects was shown in the combination group (Cl < 1). HHT and ATO induced the apoptosis of RPMI 8226 in a dose-dependent manner with typical morphological changes of apoptosis and higher early stage apoptosis rate. The enhancement in apoptotic induction was seen when two agents were combined. HHT activated expressions of Caspase-3 and PARP in a dose dependent manner at 24 h. HHT at 40 ng/mL and ATO at 8.5 micromol/L could significantly activate expressions of Caspase-3 and Caspase-9, and down-regulate expressions of anti-apoptotic proteins Bcl-xl and Mcl-1. In addition, the combination therapy of HHT at 40 ng/mL and ATO at 8.5 micromol/L inhibited phosphorylation of AKT in a time-dependent manner.

CONCLUSIONHTT, ATO, and combination therapy of HHT and ATO induced the apoptosis of RPMI 8226 cell line possibly through activating Caspase pathways, regulating expressions of Bcl-2 families, and inhibiting phosphorylation of AKT.

Apoptosis ; drug effects ; Arsenicals ; administration & dosage ; pharmacology ; Caspase 3 ; metabolism ; Caspase 9 ; metabolism ; Cell Line, Tumor ; Harringtonines ; administration & dosage ; pharmacology ; Humans ; Multiple Myeloma ; metabolism ; pathology ; Myeloid Cell Leukemia Sequence 1 Protein ; metabolism ; Oxides ; administration & dosage ; pharmacology ; Phosphorylation ; Poly (ADP-Ribose) Polymerase-1 ; Poly(ADP-ribose) Polymerases ; metabolism ; Proto-Oncogene Proteins c-akt ; metabolism ; Proto-Oncogene Proteins c-bcl-2 ; metabolism ; bcl-X Protein ; metabolism

OBJECTIVETo investigate the growth inhibition effect, cytotoxicity and apoptotic induction of harringtonine (HT) in human acute promyelocytic leukemia (APL) NB4 cells,and the related mechanism.

METHODSNB4 cells were treated with HT. Total cell numbers were counted by hemocytometer, and cell viabilities were determined by trypan blue exclusion. Apoptotic cells were determined by fluorescence microscopy and FACS after staining with AO and EB or PI, respectively. The cleavage of PARP and the activation of Bax and the expression of anti-apoptotic proteins were determined by Western Blot. siRNA was used to silence the expression of target genes. Primary cells were isolated following Ficoll-Hypaque density gradient centrifugation method.

RESULTSHT inhibited cell growth and induced apoptosis of NB4 cells in a dose- and time-dependent manner. Apoptosis induced by HT was correlated with the down-regulation of Mcl-1 and the cleavage of PARP, while HT did not affect the protein level of Bax and Bak or change the protein level of Bcl-2. The silence of Bcl-XL sensitized HT-induced apoptosis in NB4 cells.Apoptosis induced by HT in primarily cultured APL cells was also correlated with the down-regulation of Mcl-1.

CONCLUSIONHT inhibits cell growth and induces apoptosis in NB4 cells and primarily cultured APL cells, which may be associated with down-regulation of Mcl-1.

Apoptosis ; drug effects ; Cell Line, Tumor ; Harringtonines ; pharmacology ; Humans ; Leukemia, Promyelocytic, Acute ; metabolism ; pathology ; Proteins ; metabolism ; Proto-Oncogene Proteins c-bcl-2 ; metabolism ; bcl-2 Homologous Antagonist-Killer Protein ; metabolism ; bcl-2-Associated X Protein ; metabolism

OBJECTIVETo investigate the effect of homoharringtonine (HHT) on leukemic stem-like cells (LSC) in human acute myeloid leukemia (AML) cell lines.

METHODSThe phenotypes of AML cell lines U937,Kasumi-1,and KG-1 cells were analyzed by flow cytometry (FACS). The effect of HHT on leukemia stem-like cells with immunophenotype of CD34(+)CD38(-)CD96(+) was detected with FACS. Cell growth was measured by MTT assay. Activation of Caspase pathway and expression of apoptosis-related regulator proteins were examined by Western blotting.

RESULTSFACS demonstrated that the 69% of KG-1 cells expressed LSC phenotype CD34(+)CD38(-)CD96(+), while 26.7% on Kasumi-1 cells expressed this marker. In contrast,U937 cells showed CD96 negative. HHT significantly inhibited cell growth of KG-1 cells with an IC(50) of 16.9 ng/ml at 48 h. The ratio of CD34(+)CD38(-)CD96(+) cells decreased from 63.6% to 17.1% after HHT treatment. Enhanced apoptosis was demonstrated in HHT group evidenced by strong activation of Caspase-9,Caspase-3 and PARP.HHT treatment resulted in down-regulation of expression of anti-apoptotic protein BCL-2 and phosphorylated-Akt.

CONCLUSIONHHT can effectively kill the leukemic stem-like cells in human AML cell line KG1 by inhibiting cell growth and inducing apoptosis which is associated with activation of Caspase pathway and down-regulation of anti-apoptotic proteins and phosphorylated-Akt.

Antineoplastic Agents, Phytogenic ; pharmacology ; Apoptosis ; drug effects ; Caspase 3 ; metabolism ; Caspase 9 ; metabolism ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Gene Expression Regulation, Neoplastic ; Harringtonines ; pharmacology ; Humans ; Leukemia, Myeloid, Acute ; metabolism ; pathology ; Neoplastic Stem Cells ; drug effects ; metabolism ; pathology

The study was aimed to investigate the synergistically effect of interferon-α (IFN-α) and homoharringtonine (HHT) on the proliferation, apoptosis, cell cycle of K562 cells and the expression of β-catenin. The proliferation, apoptosis, cell cycle and β-catenin mRNA expression of K562 cells treated with IFN-α and/or HHT were assayed with MTT, flow cytometry or RT-PCR respectively. The results showed that HHT alone, but not IFN-α alone, displayed a proliferation inhibition, apoptosis induction, G(0)/G(1) phase block and down-regulation of β-catenin expression in K562 cells with concentration- and time-dependent manners. The expression level of β-catenin mRNA after being treated with HHT was 0.5576 ± 0.0373, which were lower than that in control group (0.9369 ± 0.0142). The down-regulation of β-catenin expression in group of IFN-α combined with HHT was higher significantly than that in HHT group (0.3737 ± 0.0529 vs 0.5576 ± 0.0373, P < 0.05). Otherwise, HHT combined with IFN-α did not demonstrate obvious toxicologic effect on bone marrow mononuclear cells. It is concluded that IFN-α combined with HHT can enhance the cytotoxic effect of HHT on K562 cells, which may be associated with down-regulation of β-catenin expression.
Cell Proliferation ; drug effects ; Harringtonines ; pharmacology ; Humans ; Interferon-alpha ; pharmacology ; K562 Cells ; beta Catenin ; genetics ; metabolism

OBJECTIVETo establish a homoharringtonine (HHT)-resistant SKM-1 cell line and explore its biologic characteristics and mechanisms for drug resistance.

METHODSThe HHT-resistant SKM-1 cell line was established by repeatedly exposing the cells to comparatively large doses of HHT with a short-time duration, and gradually elevating the drug concentration to an endurable level. The morphology of the resistant and parental cell lines was observed through optical microscope. The MTT assay was used to determine the doubling time and the resistance index to draw growth curve. The immunophenotype, cell cycle distribution and DNR accumulation between SKM-1 and SKM-1/HHT were analyzed by flow cytometry, and the karyotypes by R-banding. Semi-quantitative real-time PCR was performed to evaluate the expression levels of mdr1, MRP and topo-IIa.

RESULTSThe HHT-resistant cell line SKM-1/HHT was eventually established following 7-month drug induction. Both the resistant and the parental cell lines were similar with regard to morphology and immunophenotype. The karyotypes of the former was more complicated with differences located in chromosome 20, X, 4, 5, 9 and 11. The resistant cell line had more G(1) phase cells (64.04% vs 41.91%), less S phase cells (34.92% vs 53.53%), and less G(2) phase cells (1.04% vs 4.56%) compared with the parental cell line. The SKM-1/HHT cell line showed significant drug resistance to HHT, VCR, DNR and etoposide, the resistance indices of HHT, VCR, DNR and etoposide were 17.94, 8.75, 5.99 and 13.76 respectively. DNR accumulation was impaired in SKM-1/HHT cell line as less fluorescence of DNR (698 ± 36 vs 858 ± 54). The expression of mdr1 increased dramatically in the resistant cell line, its 2(-ΔCt) value was 20.1 higher than that of the parental cell line \[(3.42 ± 0.46)×10(-2) vs (0.17 ± 0.01)×10(-2), P < 0.05\], while MRP also increased in the resistant by 3.56 folds \[(4.77 ± 0.87)×10(-3) vs (1.34 ± 0.56)×10(-3), P < 0.05\]; However there was a slightly decrease of topo-IIa, the ratio of the resistant to the parental calculated by their 2(-ΔCt) values was 0.619:1 \[(1.91 ± 0.30)×10(-4) vs (3.08 ± 0.21)×10(-4), P < 0.05\].

CONCLUSIONA HHT-resistant cell line SKM-1/HHT was established. The prominent overexpression of mdr1 may be the main cause for multidrug resistance.

Cell Line, Tumor ; Drug Resistance, Neoplasm ; Harringtonines ; pharmacology ; Humans ; Leukemia, Myeloid, Acute ; pathology ; Myelodysplastic Syndromes ; metabolism ; pathology

This study was aimed to explore the effect of homoharringtonine in combination with AG490 on JAK2-STAT5 associated signal pathway in HEL cells, and analyze its mechanism so as to provide theoretical basis for therapy of chronic myeloproliferative neoplasma by new program. The cell survival rates were tested by MTT, apoptosis was tested by flow cytometry after HEL cells were treated by 20 ng/ml HHT, 100 µmol/L AG490 and 20 ng/ml HHT in combination with 100 µmol/L AG490, while the signal proteins such as P-JAK2, P-STAT5 and BCL-xL activated by abnormal activated JAK2 were tested by Western blot. The results showed that both HHT and AG490 could inhabit the HEL cell proliferation after being treated for 24 hours, and Annexin V-PI double staining confirmed early apoptosis while HHT effect was more obvious, Western blot showed that the expressions of P-JAK2 and P-STAT5 were down-regulated, while the total protein levels of JAK2 and STAT5 were stable. It is concluded that HHT combined with AG490 can obviously inhibit the proliferation and induce early apoptosis of HEL cells, and there is synergistic effect between the two drugs. HHT possibly acts as a broad-spectrum PTK inhibitor and synergistically with AG490 inhibits the phosphorylation of signal proteins caused by JAK2V617F, thus down-regulating the transcription of STAT5.
Cell Line, Tumor ; Harringtonines ; pharmacology ; Humans ; Janus Kinase 2 ; metabolism ; STAT5 Transcription Factor ; metabolism ; Signal Transduction ; drug effects ; Tyrphostins ; pharmacology