Immunomodulatory influences of sialylated lactuloses in mice.

The aim of this study was to investigate the immune modulatory influences of sialylated lactuloses in mice. The effects of the four sialylated lactuloses by gavage methods on the weight gain rate, organ, serum and spleen immunoglobulin of mice were investigated. Neu5Ac-α2,3-lactulose group and Kdn-α2,3-lactulose group had significantly higher weight gain rate than control group. The weight gain rate, thymus index and spleen index of Kdn-α2,3-lactulose group were significantly higher than control group and lactulose group. Liver and small intestine of Neu5Ac-α2,3-lactulose group, Neu5Ac-α2,6-lactulose group and Kdn-α2,6-lactulose group showed different degree of damage. IgG levels of serum and spleen in Neu5Ac-α2,6-lactulose group and Kdn-α2,6-lactulose group were significantly higher than control group and lactulose group. The contents of IgG in serum and spleen of Kdn-α2,3-lactulose group were significantly lower than that of control group, while the contents of IgA and IgM in serum were significantly higher than those of control group. The IgA level increased by 12.23% and 58.77% comparing with lactulose group and control group, respectively. The IgM level in serum of Kdn-α2,3-lactulose group mice increased by 43.88% and 8.05% comparing with control group and lactulose group, respectively. The IgA level and IgM level in spleen of Kdn-α2,3-lactulose group mice increased by 49.05% and 47.25% comparing with control group. In short, Kdn-α2,3-lactulose is relatively safe and superior to use as a food supplement or potential drug candidate. Our results also indicate that some other sialylated oligosaccharides are potentially harmful to organisms, they may cause some side effects.

Effects of sialylated lactulose on the mouse intestinal microbiome using Illumina high-throughput sequencing.

Sialylated oligosaccharides are known to have beneficial effects, such as increasing the level of bifidobacteria, reducing the levels of blood endotoxin and blood ammonia, and enhancing the body's immune system. However, it is unknown whether sialylated lactuloses have modulatory effects on the intestinal microbiota. In this study, 60 healthy mice were randomly divided into six groups, namely, a normal control group, a lactulose group, a Kdn-α2,3-lactulose group, a Kdn-α2,6-lactulose group, a Neu5Ac-α2,3-lactulose group, and a Neu5Ac-α2,6-lactulose group. After 14 days of lactulose administration, the feces of three mice from each group were collected, and the intestinal microbiota were detected by Illumina MiSeq high-throughput sequencing targeting the V3-V4 region of the 16S rDNA gene. At the phylum level, the relative abundance of Firmicutes was increased in the sialylated lactulose groups, while the abundance of Bacteroidetes was decreased. At the family level, sialylated lactulose intervention decreased the relative abundance of Bacteroidales S24-7 group and Helicobacteraceae and enhanced the abundance of Lactobacillaceae, which reflects the modulatory effect of sialylated lactulose on intestinal microbiota. Diversity analysis indicated that the index of Chao was higher in the sialylated lactulose groups than in the normal control group, and the Shannon and Simpson diversity indices were higher in the Kdnα-2,6-lactulose group and the Neu5Ac-α2,3-lactulose group than in the normal control group. The results of the intestinal microbiota sample composition indicated that there were differences between the sialylated lactulose groups and the normal control group. Thus, sialylated lactulose could be used as a functional food component with potential therapeutic applications in manipulating intestinal microbiota to exert beneficial effects on the host's health.

Effects of Frozen Storage Time, Thawing Treatments, and Their Interaction on the Rheological Properties of Non-Fermented Wheat Dough.

In this study, the effects of frozen storage time, thawing treatments, and their interaction on the rheological properties of non-fermented dough were evaluated. Texture profile analysis (TPA), rheological measurements, including strain/frequency sweep, and creep-recovery measurement were applied to the dough. Compared with unfrozen fresh dough, the frozen storage time (S) and thawing treatment (T) influenced almost all indicators significantly, and their mutual effects (S × T) mainly affected the hardness and springiness. Frozen time was the main factor resulting in the destruction of non-fermented dough during the thawing treatments. Moreover, refrigerator thawing (4 °C) produced a dough with minimal changes in the rheological properties, regardless of the frozen storage time. Meanwhile, microwave thawing resulted in lower G' and lower zero shear viscosity (η0) values, as well as higher maximum creep compliance (Jmax) and hardness values. Moreover, the difference between the three thawing treatments was exacerbated after 30 days of frozen storage. SEM images also showed that long-term frozen storage combined with microwave thawing seriously destroyed the rheological properties, structural stability, and inner microstructure of the dough.

Effect of low temperature on the aging characteristics of a potato starch gel.

In this work, the freezing curve of a potato starch gel with different concentrations was determined. The water migration, texture, microstructure and gelatinization of a potato starch gel with 8% starch concentration were studied during aging. The results showed that the freezing characteristics of the potato starch gel with different starch concentrations were quite different. NMR results showed that the relaxation time and proportion of water with different existing states (T21, T22 and T23) in the potato starch gel varied significantly under different aging temperatures. Under different aging temperatures, the texture characteristics and the gel strength of the starch gel were significantly different. The water retention of the gel was better under aging temperatures of 3 °C and -3 °C than for other gel samples. SEM and C-cell results showed that under aging temperatures of 3 °C and 0 °C, the formation of a gel network structure was accelerated, and the gel was relatively firm, with small and uniform pores and a larger pore area and number. The rapid viscosity analysis results showed that the peak viscosity, breakdown and setback of the vacuum freeze-dried gel powder changed differently under the aging temperatures.

[Enhancing effect of matrine on the tumor-inhibition by TIM2 gene-modified hepatocarcinoma H22 cells in mice].

OBJECTIVE: To investigate the effects of matrine on the anti-tumor efficiency of TIM2 gene-modified murine hepatocarcinoma H22 cells. METHODS: A combined eukaryotic expression vector pIRES2-EGFP-TIM2 was constructed and transfected into H22 cells by lipofectamin. The monoclone of positive H22-TIM2 cells and negative control H22-EGFP cells transfected with pIRES2-EGFP vector were selected by G418 pressure and limited dilution method in turn and were inoculated to establish the tumor-bearing mouse model. Next, matrine was administered to the tumor-bearing mice and the inhibitory effect of matrine was determined. RESULTS: The co-expression of EGFP protein and TIM2 gene was detected in H22 cells selected after TIM2 gene transfecion. After subcutaneous injection of H22-TIM2 cells, the rate of tumor formation (41%) was lower than that of H22 cells and H22-EGFP cells injection (92%) in mice. The tumor growth was significantly inhibited in mice vaccinated with H22-TIM2 cells. After the experiment was completed, the volume of tumors in mice of H22-TIM2 group was 31.34 +/- 9.21 mm3, smaller than those in H22-EGFP group (98.25 +/- 25.23)mm3 and H22 cells group (114.08 +/- 36.45)mm3 (P < 0.01). Matrine dramatically enhanced the anti-tumor efficiency of TIM2 gene-modified H22 cells, with the highest tumor inhibitory rate (IR) 90.6% among the H22-TIM2 group, matrine treatment group and H22-EGFP cells combined with matrine treatment group (69.2%, 67.5% and 70.8%, respectively) in the experimental mice. CONCLUSION: The tumorigenesity of H22 cells has been markedly impaired after modification by TIM2 gene. Matrine can enhance its inhibitory effect on tumors of H22-TIM2 cells in vivo. These data indicate importance to further study on the biological role of TIM2 gene in tumor immunity and explore the molecular mechanism of matrine in suppressing of tumor growth.

[Effects of matrine on oncogenicity of H22 cells modified by TIM2 gene in vivo].

OBJECTIVE: To investigate the effects of matrine on the anti-tumor efficiency of H22 murine hepatocarcinoma cell-based vaccine modified by TIM2 gene in vivo. METHOD: The combinant eukaryotic expression vector pIRES2-EGFP-TIM2 was constructed and transfected into H22 cells by lipofectamin. The monoclone of the positive H22-TIM2 cells and negative control H22-EGFP cells were selected by G418 pressure and limited dilution method in turn. The H22 whole-cell-based vaccine were inoculated to establish the tumor-bearing mouse model, and its oncogenicity and immunogenicity were observed in vivo. Then the matrine was administered to the tumor-bearing mice inoculated by H22-TIM2 cells, H22-EGFP cells and H22 cells, and the inhibitory effect of matrine on tumor was studied. RESULT: The co-expression of EGFP protein and TIM2 mRNA were detected in H22-TIM2 cells. The rate of tumor formation in mice injected of H22-TIM2 cells was 41%, lower than that of H22 cells and H22-EGFP cells injection (92%) in mice. The growth of tumor were significantly inhibited vaccinated with H22-TIM2 cells in mice. The inhibitory rate of tumor (IR) was 69.2% in mice of H22-TIM2 group, higher than that of mice treated with matrine and H22 cells injection, the later was 67.5%. Matrine could dramatically strengthen the anti-tumor efficiency of H22 cells modified by TIM2 gene, with the highest tumor inhibitory rate (IR) (90.6%) in all the experimental mice. The spleen index, populations of CD4-positive lymphocytes and the ratio of CD4-positive to CD8-positive lymphocytes of spleen in mice vaccinated of H22-TIM2 cells were obviously higher than those in the other groups. CONCLUSION: The oncogenicity of H22 cells is markedly impaired after modified by TIM2 gene. Matrine can strengthen the inhibitory effect of H22-TIM2 cells on tumor in mice. These data give us important clues to further study the biological role of TIM2 gene in tumor immunity and explore the molecular mechanism of matrine in suppressing tumor.

Molecular mechanism of matrine-induced apoptosis in leukemia K562 cells.

Matrine, a low toxic alkaloid purified from the Chinese herb Kushen, has been reported to induce apoptosis in leukemia K562 cells. In this study, the mechanism underling this apoptotic event was investigated. Treatment of K562 cells with matrine resulted in inhibition of cell survival more significantly than treatment of non-cancer fibroblast NIH3T3 cells. When K562 cells were incubated with matrine in higher than 0.2 mg/ml doses for 48 hours, the apoptotic cells were increased and both poly (ADP-ribose) polymerase (PARP) and caspase-3 were cleaved in a dose dependent manner. General caspase inhibitor (z-VAD-fmk) or caspase-3 inhibitor (z-DEVD-fmk) almost completely suppressed matrine-induced apoptosis. In addition, matrine increased proapoptotic protein bax and caused the release of cytochrome C. Taken together, the results suggest that matrine induces a cytochrome C-mediated, caspase-dependent apoptosis.

Ursolic acid-mediated apoptosis of K562 cells involves Stat5/Akt pathway inhibition through the induction of Gfi-1.

Ursolic acid (UA) is a promising natural compound for cancer prevention and therapy. We previously reported that UA induced apoptosis in CML-derived K562 cells. Here we show that the apoptotic process is accompanied by down-regulation of Bcl-xL and Mcl-1 expression and dephosphorylation of Bad. These events are associated with Stat5 inhibition, which is partially mediated through elevated expression of transcriptional repressor Gfi-1. Gfi-1 knockdown using siRNA abrogates the ability of UA to decrease Stat5b expression and attenuates apoptosis induction by UA. We also demonstrate that UA suppresses the Akt kinase activity by inhibiting Akt1/2 expression, which correlates with Stat5 inhibition. Stat5 activity inhibited by a chemical inhibitor or siRNA, Akt1/2 mRNA expression is suppressed. Moreover, we show that UA exerts growth-inhibition in Imatinib-resistant K562/G01. UA has synergistic effects when used in combination with Imatinib in both K562 and K562/G01. Altogether, the data provide evidence that UA's pro-apoptotic effect in K562 cells is associated with the Gfi-1/Stat5/Akt pathway. The findings indicate that UA could potentially be a useful agent in the treatment of CML.

Fractalkine gene therapy for neuroblastoma is more effective in combination with targeted IL-2.

The induction of tumor protective immunity against neuroblastoma remains a major challenge for active immunotherapy. Fractalkine is a unique Th1 CX3C chemokine known to induce adhesion and migration of leukocytes mediated by both, a membrane-bound and soluble form, respectively. Here, we tested the hypothesis that chemokine gene therapy with fractalkine (FKN) induces an effective anti-neuroblastoma immune response amplified by targeted IL-2 using the anti-GD2 antibody ch14.18 fused with IL-2 (ch14.18-IL-2). For this purpose, NXS2 cells were genetically engineered to stably produce murine FKN (NXS2-FKN). Transcription and expression of the mFKN gene in tumor tissue of mice inoculated with NXS2-FKN cells were demonstrated in vivo. Importantly, mFKN exhibited a reduction in primary tumor growth and spontaneous liver metastases in syngenic A/J mice. This effect was boosted by targeted IL-2 using small non-curative doses of ch14-18-IL-2. The amplification of the FKN induced immune response was specific, since a non-specific antibody-IL-2 fusion protein ch225-IL-2 was ineffective. In summary, we demonstrated for the first time that chemokine gene therapy is amplified by targeted IL-2 suggesting a combination of both strategies as an adjuvant therapy for neuroblastoma.

[Inhibition of tumor growth in tumor-bearing mice treated with matrine].

OBJECTIVE: To investigate the inhibitory effect of matrine on tumor growth in tumor-bearing mice and explore its possible mechanisms of anti-tumor action in vivo. METHODS: Hepatocellular carcinoma cells H(22) were subcutaneously injected into BALB/c mice and matrine was administered to the tumor-bearing mice. The kinetics of tumor formation and tumor growth were measured, tumor growth inhibition rate (IR) was calculated, and tumor tissue samples were taken and examined by light and electron microscopy to assess the inhibitory effects of matrine on tumor growth in the mice. RESULTS: Marked inhibitory effect of matrine on the transplanted hepatocellular carcinoma H(22) was observed in the tumor-bearing mice. The inhibitory rates were 62.5% and 60.7% in the groups treated with high and low dosage of matrine, respectively (P < 0.01 vs. control group). The tumor formation was significantly retarded and tumor growth was inhibited in matrine-treated groups compared with those in control mice. Histopathological examination revealed widespread necrosis with massive accumulation of infiltrating lymphocytes and plasmacytes in the tumors. Numerous apoptotic cells and apoptotic bodies were observed in the tumors under the electron microscope. CONCLUSION: Matrine has marked inhibitory effects on tumor growth in vivo, which is probably related to inhibition of cell division and tumor cell proliferation, directly killing of tumor cells and/or induction of apoptosis and modulation of anti-tumor immune responses.

[Construction of eukaryotic expression vector of unknown KH gene and its effect on cell proliferation].

OBJECTIVE: To construct an eukaryotic expression vector of open reading frame of unknown KH gene (KH-ORF), and investigate its effect on cell proliferation. METHODS: The pCI-neo-KH-ORF expression vector was constructed by DNA recombinant technique and was introduced into COS-7 cells and K562 cells by lipofectactin-mediated DNA transfection. Expression of KH-ORF mRNA was detected by RT-PCR. The effect of KH-ORF on cell cycle of COS-7 cells and K562 cells was evaluated by flow cytometry (FCM). Effect on cell proliferation of COS-7 cells was tested by MTT assay and that on K562 cells was analyzed by growth curves and LDH activity measurement. RESULTS: (1) KH-ORF mRNA was expressed both in COS-7 cells and K562 cells. (2) The cell cycle and cell proliferation of COS-7 cells were unaffected significantly. (3) The proportion of cells in S phase was increased in pCI-neo-KH-ORF-transfected K562 cells; and growth curves and LDH activity indicated enhanced cell proliferation. CONCLUSION: KH gene may be a leukemia gene related to proliferation of K562 cells.

Sertoli cell-mediated differentiation of male germ cell-like cells from human umbilical cord Wharton's jelly-derived mesenchymal stem cells in an in vitro co-culture system.

BACKGROUND: Microenvironment signals play a critical role in directing the differentiation of stem cells. Sertoli cells (SCs) provide a unique microenvironment that is essential for germ cell differentiation. METHODS: Our previous study has demonstrated that human umbilical cord Wharton's jelly-derived mesenchymal stem cells (HUMSCs) could differentiate towards male germ cells in vitro, but HUMSC-derived germ-like cells expressed only few germ cell markers. The aim of this study was to investigate the effect of SCs on the differentiation of HUMSCs towards male germ cells using a co-culture system that mimicked the in vivo male germ cell microenvironment. RESULTS: HUMSCs formed clump-like features on SC monolayers after seeding for 3 weeks. Differentiated cells formed round colonies that share the morphological features of spermatogonial colonies. RT-PCR, immunofluorescence, confocal microscopy, and Western blot analyses revealed the expression of early germ cell markers STELLA and VASA and male germ cell-specific marker DAZL in differentiated HUMSCs, confirming the presence of cells with characteristics of male germ cells. CONCLUSION: The HUMSC-SC co-culture system mimics a native microenvironment for germ cell colonization without any in vitro artificial manipulation and can be used to explore the mechanisms controlling the differentiation of male germ cells from HUMSCs. Male germ cells derived from HUMSCs may be used in the therapy for male infertility.

Programming of human umbilical cord mesenchymal stem cells in vitro to promote pancreatic gene expression.

Human umbilical cord mesenchymal stem cells (HUMSCs) are candidates for tissue engineering and may potentially be used for transdifferentiation into pancreatic endocrine cells. The adenoviral vector is effective in transducing genes into stem cells that are refractory to gene delivery by non­viral approaches. qPCR was used to detect the pancreatic endogenous gene expression of HUMSCs transfected by islet cell-specific transcription factors (TFs). In the present study, using adenoviruses, the mouse TFs, pancreatic and duodenal homeobox 1 (pdx1), V-maf musculoaponeurotic fibrosarcoma oncogene homolog A (mafa) and class B basic helix­loop­helix factor neurogenin 3 (ngn3), which are essential for pancreatic cell development, were introduced into HUMSCs to assess the expression of the pancreatic genes, glucagon, pdx1 and nk2 homeobox 2 (nkx2.2). When pdx1, mafa and ngn3 were cotransduced into HUMSCs, the expression of glucagon increased by 21­fold at days 3 and 7 following transduction, while the endogenous pdx1 gene expression was increased by 15­fold at day 3 and decreased by 70% at day 7. When mafa and ngn3 were cotransduced into HUMSCs, there was a 5­fold increase in pdx1 gene expression at day 7, but no activation was observed at day 3. When mafa alone was introduced into HUMSCs, the pdx1 gene expression was elevated by 6­fold at day 3 and decreased by 3­fold at day 7. Transduction of ngn3 alone into HUMSCs induced nkx2.2 gene expression at day 3 but the expression levels were decreased at day 7. However, when pdx1 and ngn3 were cotransduced into HUMSCs, the expression levels of glucagon, pdx1 and nks2.2 were all lower than those observed with pdx1 or ngn3 transduction alone. These results suggested that the transduction of pdx1, mafa and ngn3 genes into HUMSCs induced the expression of the pancreatic genes, glucagon, pdx­1 and nkx2.2, and that the expression was time dependent. In addition, different combinations of the TFs may demonstrate synergistic or antagonistic effects. This data may be beneficial for guiding future studies obtaining mature pancreatic endocrine cells from HUMSCs.

Pentamidine sensitizes chronic myelogenous leukemia K562 cells to TRAIL-induced apoptosis.

Pentamidine (PMD) is an anti-protozoa drug with potential anticancer activity. Here we show that PMD at clinically achievable plasma drug concentrations slightly inhibited the growth of human leukemia cell lines. PMD close to its therapeutic doses sensitized TRAIL-resistant K562 cells to the cytokine and potentiated TRAIL-induced apoptosis through activation of caspase-8 and -3. When we investigated the underlying mechanism, we observed that treatment with PMD increased DR5 expression at both mRNA and protein levels and down-regulated anti-apoptotic XIAP and Mcl-1 protein levels. This study provides a rationale for a more in-depth exploration into the combined treatment with PMD and TRAIL as a valuable strategy for leukemia therapy.

In vitro anti-tumour activities of quinolizidine alkaloids derived from Sophora flavescens Ait.

The dry root of Sophora flavescens Ait. (SF) has long been used in a variety of Chinese herbal formulations to treat patients with cancer. Alkaloids are commonly known to present in SF as main active constituents. Here, we report that among the six characterized SF-derived quinolizidine alkaloids including sophoridine, aloperine, sophocarpine, matrine, oxymatrine and cytisine, aloperine exerted the most potent in vitro cytotoxic activity against the human cancer cell lines and oxymatrine exhibited selective anti-cancer activity against hepatocellular carcinoma HepG2 cells. Analysis of DNA fragmentation and PARP cleavage revealed that aloperine treatment for 48 hr induced apoptosis in HL-60 cells. In addition, autophagic formation of acidic vacuole was also observed in HL-60 cells exposed to aloperine. These results suggest that aloperine may be a novel contributor to the anti-cancer properties of SF.

Growth-inhibiting effects of arsenic trioxide plus epigenetic therapeutic agents on leukemia cell lines.

Arsenic trioxide (ATO) is an effective therapeutic agent for acute promyelocytic leukemia (APL) and other hematopoietic malignancies. We found that ATO down-regulated the global DNA methylation level in HL-60 cells with high-performance capillary electrophoresis (HPCE) assay. Using combination index method of Chou and Talalay, interactions between ATO and epigenetic therapeutic agents were analyzed in three human leukemia cell lines (HL-60, U937, and K562). A synergistic interaction was observed in HL-60 cells between ATO and 5-Aza-2'-Deoxycytidine (DAC), while an antagonistic interaction was found in U937 cells between ATO and valproic acid (VPA). The combination of ATO with trichostatin A (TSA) caused an antagonistic interaction in U937 and K562 cells. These results not only highlight possible diversity of the anti-leukemia mechanisms of ATO, but also provide initial guide for further investigation of leukemia therapies based on the combination of ATO with epigenetic agents.

Gossypol inhibits phosphorylation of Bcl-2 in human leukemia HL-60 cells.

Gossypol is an attractive therapeutic anti-tumor agent as an apoptosis inducer and is being evaluated in preclinical tests. However, the molecular mechanisms underlying apoptosis induction by gossypol in malignant cells have not been completely enunciated. Here we investigate the alterations of Bcl-2/Bcl-xL/Mcl-1 protein levels and Bcl-2 phosphorylation in gossypol-induced apoptosis in human leukemia HL-60 cells. We found that gossypol treatment inhibited cell growth and induced apoptosis in HL-60 cells. Bcl-2/Bcl-xL/Mcl-1 protein levels were slightly reduced and phosphorylation of Bcl-2 at threonine 56 (phospho T56) was not altered. However, phosphorylation of Bcl-2 at serine 70 (phospho S70) was strikingly down-regulated in gossypol-exposed cells. This reduction was found to be not only in both dose- and time-dependent fashion but also obviated by phorbol l2,13-dibutyrate (PDBu), an activator of protein kinase C (PKC). In addition, pre-treatment of PDBu partially prevented gossypol-induced apoptosis in HL-60 cells. Collectively, gossypol treatment can reduce phosphorylation of Bcl-2 at serine 70 in leukemia HL-60 cells and gossypol may be a promising therapeutical candidate for leukemia patients especially expressing phosphorylated Bcl-2 at Ser70.

Lycorine induces apoptosis and down-regulation of Mcl-1 in human leukemia cells.

Lycorine is an alkaloid isolated from the bulb of the Amaryllidaceae Lycoris. Here, we report that treatment with lycorine resulted in survival inhibition and apoptosis induction in human leukemia cell lines. Lycorine induced apoptosis in human leukemia cells via intrinsic mitochondria pathway and caused a rapid-turnover of protein level of Mcl-1 which occurred before caspases activation. Furthermore, pronounced apoptosis accompanied by the down-regulation of Mcl-1 was also observed in blasts from patients with acute myeloid leukemia. Our findings suggest that lycorine may be a good candidate therapeutic agent against leukemia in worth of further evaluation.

Anticancer effects of the Chinese medicine matrine on murine hepatocellular carcinoma cells.

Matrine is a component of the traditional Chinese medical herb Sophora flavescens Ait, which is widely used to treat diseases such as viral hepatitis, cardiac arrhythmia and skin inflammations. As indicated by previous reports, the molecular mechanism of matrine's anti-cancer effect has been poorly clarified. In this study, we used both in vitro and in vivo models to investigate matrine's antitumor effect and its possible molecular mechanisms. Murine hepatocellular carcinoma H22 cells were cultured in the presence of matrine at various concentrations (0.2 - 2.0 mg/mL). A dose-dependent antiproliferation effect was observed. The 50 % inhibitory concentration (IC (50)) was 0.6 mg/mL. Antiproliferation effects of matrine were associated with an increase in cells arrested in the G (1) phase of the cell cycle. Morphological changes, flow cytometric analysis and expression of the proapoptotic protein Bax indicated that this anticancer effect was mediated via apoptosis. In vivo antitumor efficacy was evaluated following S. C. inoculation of H22 cells in BALB/c mice. Matrine administrated I. P. resulted in strong in vivo anticancer activity. Our results showed that seven doses of matrine at 50 mg/kg/dose inhibited 60.7 % of tumor growth. Transmission electron microscope (TEM) analysis and histoimmunochemical staining for Bcl-2 and Bax proteins also indicated induction of apoptosis in tumor tissues by matrine. Taken together, our results demonstrate that matrine possesses strong antitumor activities in vitro and in vivo. Inhibition of cell proliferation and induction of apoptosis are the likely mechanisms responsible for matrine's antitumor activities.

Induction of apoptosis and regulation of the MAPK pathway by ursolic acid in human leukemia K562 cells.

Ursolic acid (UA) is a pentacyclic triterpene acid naturally occurring in a number of foods and medicinal plants. It is one of the most promising chemopreventive agents and has been reported to induce apoptosis in many cancer cells. Here, we report that treatment with UA induces apoptosis in human leukemia K562 cells and down-regulates protein levels of bcl-xL. Treatment also increases phospho-JNK in a dose- and time-dependent manner but does not alter phospho-Erk1/2 and phospho-P38. These results suggest that JNK may participate in UA-induced apoptosis in K562 cells.