In Vivo Antitumor Effect of Supercritical CO2 Extract of Mango Ginger ( Curcuma amada Roxb) in U-87MG Human Glioblastoma Nude Mice Xenografts.

Glioblastoma multiforme (GBM) is one the most aggressive and lethal human neoplasms with poor prognosis and very limited positive treatment options. The antitumor effect of supercritical CO2 extract of mango ginger ( Curcuma amada Roxb) (CA) with and without irinotecan (IR) was analyzed in U-87MG human glioblastoma multiforme (GBM) cells in vitro and in nude mice xenografts. CA is highly cytotoxic to GBM cells and is synergistic with IR as indicated by the combination index values of <1 in the CompuSyn analysis. CA inhibits tumor growth rate in GBM xenografts, the inhibition rate being higher than in IR treated group. GBM xenograft mice treated with IR + CA combination showed almost complete inhibition of tumor growth rate. Gene expression analysis of xenograft tumors indicated that IR + CA treatment significantly downregulated anti-apoptotic (Bcl-2 and mutant p53), inflammation-associated (COX-2) and cell division-associated (CCNB2) genes and upregulated pro-apoptotic genes (p21 and caspase-3). These results confirmed the therapeutic efficiency of IR + CA combination against GBM and the need for further clinical investigations.

Inhibition of AKT signaling by supercritical CO2 extract of mango ginger (Curcuma amada Roxb.) in human glioblastoma cells.

BACKGROUND: Mango ginger (Curcuma amada Roxb.) is a less-investigated herb for anticancer properties than other related Curcuma species. AKT (a serine/threonine protein kinase B, originally identified as an oncogene in the transforming retrovirus AKT8) plays a central role in the development and promotion of cancer. In this investigation, we have analyzed the effect of supercritical CO2 extract of mango ginger (CA) on the genetic pathways associated with AKT signaling in human glioblastoma cells. METHODS: The inhibitory effect of supercritical CO2 extract of mango ginger (Curcuma amada) on AKT signaling was investigated in U-87MG glioblastoma cells. RESULTS: CA was highly cytotoxic to glioblastoma cell line (IC50=4.92±0.81 µg/mL) compared to mHypoE-N1 normal mouse hypothalamus cell line (IC50=40.57±0.06 µg/mL). CA inhibits AKT (protein Kinase B) and adenosine monophophate -activated protein kinase α (AMPKα) phosphorylation significantly in a dose-dependent manner. The cell migration which is necessary for invasion and metastasis was also inhibited by CA treatment, with about 43% reduction at 20 µg/mL concentration. Analysis of mRNA and protein expression of genes associated with apoptosis, cell proliferation and angiogenesis showed that CA modulates expression of genes associated with apoptosis (Bax, Bcl-2, Bcl-X, BNIP3, caspase-3, mutant p53 and p21), cell proliferation (Ki67) and angiogenesis vascular endothelial growth factor (VEGF). Additionally, heat shock protein 90 (HSP90) and AMPKα genes interacting with the AKT signaling pathway were also downregulated by CA treatment. CONCLUSIONS: These results indicate the molecular targets and mechanisms underlying the anticancer effect of CA in human glioblastoma cells.

Therapeutic Effect of Supercritical CO2 Extracts of Curcuma Species with Cancer Drugs in Rhabdomyosarcoma Cell Lines.

Synergistic effect of supercritical CO2 extracts of Curcuma species with conventional chemotherapeutic drugs was investigated in human alveolar (SJRH30) and embryonal (RD) rhabdomyosarcoma cell lines. The Curcuma amada (mango ginger) (CA) extract showed the highest levels of cytotoxicity with inhibitory concentration IC50 values of 7.133 µg/ml and 7.501 µg/ml for SJRH30 and RD cell lines, respectively, as compared with Curcuma longa (turmeric) and Curcuma xanthorrhiza (Javanese turmeric) extracts. CA showed synergistic cytotoxic effects with vinblastine (VBL) and cyclophosphamide (CP) as indicated by the combination index values of <1 for VBL + CA, CP + CA, and VBL + CP + CA combinations in both embryonal and alveolar rhabdomyosarcomas. When lower doses of CA (0.1-0.2 µg/ml) were combined with cancer drugs like CP and VBL, caspase-3 activity increased significantly compared with individual agents and correlated with the percentage of apoptotic cells. CA in combination with VBL and CP induced a higher percentage of apoptosis than single agents in both cell lines. CA also modulated the expression of genes associated with intrinsic pathway of apoptosis (Bcl-2, Bax, Bak, and p53) and also inhibited the expression of genes associated with inflammation such as COX-2 and NF-κB. Xenograft studies with SJRH30 tumors in nude mice showed that CA treatment inhibited tumor growth rate with and without VBL and increased the survival rate significantly. These results suggest that CA can be evaluated further as an adjuvant with cancer drugs for the treatment of rhabdomyosarcoma patients. Copyright © 2015 John Wiley & Sons, Ltd.

Anticancer potential and mechanism of action of mango ginger (Curcuma amada Roxb.) supercritical CO2 extract in human glioblastoma cells.

Mango ginger (Curcuma amada Roxb.) is among the less-investigated species of Curcuma for anticancer properties. We have investigated the anticancer potential and the mechanism of action of a supercritical CO2 extract of mango ginger (CA) in the U-87MG human glioblastoma cell line. CA demonstrated higher cytotoxicity than temozolomide, etoposide, curcumin, and turmeric force with IC50, IC75, and IC90 values of 4.92 µg/mL, 12.87 µg/mL, and 21.30 µg/mL, respectively. Inhibitory concentration values of CA for normal embryonic mouse hypothalamus cell line (mHypoE-N1) is significantly higher than glioblastoma cell line, indicating the specificity of CA against brain tumor cells. CompuSyn analysis indicates that CA acts synergistically with temozolomide and etoposide for the cytotoxicity with combination index values of <1. CA treatment also induces apoptosis in glioblastoma cells in a dose-dependent manner and downregulates genes associated with apoptosis, cell proliferation, telomerase activity, oncogenesis, and drug resistance in glioblastoma cells.

Improved neuroprotective effects by combining Bacopa monnieri and Rosmarinus officinalis supercritical CO2 extracts.

Ethnobotanical evidence suggests that herbs such as brahmi (Bacopa monnieri) and rosemary (Rosmarinus officinalis) may possess antioxidant and neuroprotective properties. We compared the antioxidant and neuroprotective effects of supercritical extract of Bacopa monnieri and rosemary antioxidant extract obtained from Rosmarinus officinalis as well as their combination to examine the effects on human glial (U-87 MG) and embryonic mouse hypothalamus cells. Bacopa monnieri extract, rosemary antioxidant extract, and their combination (1:1) are not cytotoxic in both glial and embryonic mouse hypothalamus cell lines up to 200 µg/mL concentration. The combination of extracts of Bacopa monnieri + rosemary antioxidant has better antioxidant potential and antilipid peroxidation activity than either agent alone. Although the extract of Bacopa monnieri + rosemary antioxidant showed almost similar inhibition of phospho tau expression as Bacopa monnieri or rosemary antioxidant extract alone, the combination has better inhibitory effect on amyloid precursor protein synthesis and higher brain-derived neurotrophic factor production in hypothalamus cells than single agents. These results suggest that the extract of Bacopa monnieri + rosemary antioxidant is more neuroprotective than Bacopa monnieri or rosemary antioxidant extract.

Potentiation of etoposide and temozolomide cytotoxicity by curcumin and turmeric force™ in brain tumor cell lines.

We have investigated on the potentiation of etoposide (ETP) and temozolomide (TMZ) cytotoxicity in U-87MG glioblastoma and D283 medulloblastoma cell lines by curcumin (CUR) and turmeric force (TF), a nutraceutical formulation of turmeric, with the objective of assessing the potential for their adjuvant use in brain tumor chemotherapy. While U-87MG cell line was generally resistant to TMZ, IC50 values for CUR and TF were 37.33 and 30.75 µg/ml, respectively. TF is the only agent that demonstrated efficacy at the IC90 level. When CUR or TF was combined with ETP and TMZ, increased chemotherapeutic efficiency in the U-87MG cells was observed. TF is highly cytotoxic to D283 Med cell line compared to curcumin with an IC50 value of 1.55 ug/ml. Although both CUR and TF potentiated ETP and TMZ cytotoxicity, TF is more efficient than CUR in both U-87MG and D283 Med cell lines. Treatment of U-87MG cells with the triple combination of TMZ+ETP+TF induced a high percentage of apoptotic cells. Potential mechanisms that may explain evidence of synergy include down regulation of p10 and p53 mRNAs and increase in BAX/Bcl-2 mRNA ratio. These pre-clinical results suggest that TF may be useful as an adjuvant with ETP and TMZ for brain tumor chemotherapy.

Potentiation of gemcitabine by Turmeric Force in pancreatic cancer cell lines.

Gemcitabine is a first line cancer drug widely used for the treatment of pancreatic cancer. However, its therapeutic efficiency is significantly limited by resistance of pancreatic cancer cells to this and other chemotherapeutic drugs. We have investigated the cytotoxic effect of Turmeric Force (TF), a supercritical and hydroethanolic extract of turmeric, alone and in combination with gemcitabine in two pancreatic carcinoma cell lines (BxPC3 and Panc-1). TF is highly cytotoxic to BxPC3 and Panc-1 cell lines with IC50 values of 1.0 and 1.22 microg/ml, respectively with superior cytotoxicity than curcumin. Gemcitabine IC50 value for both of these cell line is 0.03 microg/ml; however, 30-48% of the pancreatic cancer cells are resistant to gemcitabine even at concentrations >100 microg/ml. In comparison, TF induced cell death in 96% of the cells at 50 microg/ml. The combination of gemcitabine and TF was synergistic with IC90 levels achieved in both pancreatic cancer cell lines at lower concentrations. CalcuSyn analysis of cytotoxicity data showed that the Gemcitabine + Turmeric Force combination has strong synergism with combination index (CI) values of 0.050 and 0.183 in BxPC3 and Panc-1 lines, respectively at IC50 level. This synergistic effect is due to the increased inhibitory effect of the combination on nuclear factor-kappaB activity and signal transducer and activator of transcription factor 3 expression as compared to the single agent.

Isolation and characterization of an anticancer catechol compound from Semecarpus anacardium.

ETHNOPHARMACOLOGICAL RELEVANCE: The fruits and seeds of Semecarpus anacardium are used widely for the treatment of human cancers and other diseases in the Ayurvedic and Sidda systems of medicine in India. AIM OF THE STUDY: The principal aim of this investigation was to isolate and characterize the anticancer compound from the kernel of Semecarpus anacardium nut. MATERIALS AND METHODS: The bioactivity-tailored isolation and detailed chemical characterization were used to identify the active compound. Cytotoxicity, apoptosis, cell cycle arrest as well as synergism between the identified anticancer compound and doxorubicin in human tumor cell lines were analyzed. RESULTS: GC/MS, IR, proton NMR, carbon NMR and collisionally induced dissociation (CID) spectra analysis showed that the isolated active compound is 3-(8'(Z),11'(Z)-pentadecadienyl) catechol (SA-3C). SA-3C is cytotoxic to tumor cell lines with IC(50) values lower than doxorubicin and even multidrug resistant tumor cell lines were equally sensitive to SA-3C. SA-3C induced apoptosis in human leukemia cell lines in a dose-dependent manner and showed synergistic cytotoxicity with doxorubicin. The cell cycle arrest induced by SA-3C at S- and G(2)/M-phases correlated with inhibition of checkpoint kinases. CONCLUSION: SA-3C isolated from the kernel of Semecarpus anacardium can be developed as an important anticancer agent for single agent and/or multiagent cancer therapy.

Mechanism of macrophage activation by (1,4)-alpha-D-glucan isolated from Tinospora cordifolia.

The signaling mechanism of the novel (1,4)-alpha-D-glucan (RR1) isolated from the medicinal plant Tinospora cordifolia was investigated in macrophages to evaluate its immunostimulating properties. When RAW264.7 macrophages were incubated with RR1 at 4 degrees C, the novel glucan inhibited the phagocytosis of unopsonized zymosan A bioparticles in a dose-dependent manner. RR1 also inhibited the binding and internalization of opsonized zymosan A bioparticles, although at a lower level than laminarin. Incubation of macrophages with anti-CD11b mAb followed by RR1 failed to show any inhibitory effect on RR1-induced TNF-alpha synthesis confirming that complement receptor 3 (CR3) is not involved in the opsonic binding and internalization of RR1 in macrophages unlike zymosan A. The anti-CD11b mAb has significant inhibitory effect on the zymosan A-induced tumor necrosis factor (TNF)-alpha synthesis. RR1 induced TNF-alpha synthesis in macrophages in a dose-dependent manner which can be completely inhibited by the NF-kappaB inhibitor caffeic acid phenethyl ester (CAPE) or curcumin. RR1 activated NF-kappaB in a time- and dose-dependent manner and this modulation of nuclear NF-kappaB activity is associated with the degradation of I-kappaB alpha thus facilitating the translocation of NF-kappaB into the nucleus. RR1-induced NF-kappaB activity peaks at 8 h of RR1 stimulation while I-kappaB alpha degradation occurred within 1 h of stimulation. RR1-induced NF-kappaB activation occurred through TLR6 signaling as evidenced by the synthesis of IL-8 in TLR6-transfected HEK293 cells. These results show that the novel (1,4)-alpha-D-glucan from Tinospora cordifolia activates the immune system through the activation of macrophages that occurs through TLR6 signaling, NF-kappaB translocation and cytokine production.

Anticancer effects of amooranin in human colon carcinoma cell line in vitro and in nude mice xenografts.

Amooranin (AMR), a natural triterpenoid drug isolated and characterized from Amoora rohituka stem bark, is cytotoxic to SW620 human colon carcinoma cell line with an IC(50) value of 2.9 microg/ml. This novel compound caused depolarization of mitochondrial membrane and decrease of membrane potential, indicating initial signal of apoptosis induction. The percentage of cells with decreased mitochondrial potential ranged from 7.4% at 1 microg/ml to 60.5% at 100 microg/ml AMR. Flow cytometric analysis of apoptosis using Annexin-V-FITC staining showed that the percentage of apoptotic cells ranged from 7.5% at 1 microg/ml to 59.2% at 100 microg/ml AMR. AMR-induced apoptosis was accompanied by redistribution of cytochrome c from mitochondria to cytosol as well as down regulation of Bcl-2 and Bcl-X(L) proteins in a dose-dependent manner. SW620 human colon carcinoma xenograft mice treated with AMR showed significant reduction in tumor growth rates compared to saline- and doxorubicin-treated groups. The reduction in tumor growth rate was better in xenografts treated with 2 mg/kg AMR than 5 and 10 mg/kg treated mice. The analysis of global gene expression changes induced by AMR in xenograft tumors by microarray hybridization revealed that several genes involved in energy pathways, transport, apoptosis, immune response, nucleic acid metabolism, protein metabolism, cell growth and/or maintenance, signal transduction and cell communication, were affected by this natural cancer drug. These results suggest that the anticancer properties of AMR in SW620 human colon carcinoma cell line are mediated through its effects on functional genomics, targeting the apoptotic process.

Expression profiles of apoptotic genes induced by curcumin in human breast cancer and mammary epithelial cell lines.

Curcumin (diferuloyl methane), the yellow-colored dietary pigment from the rhizomes of turmeric, has been recognized as a chemopreventive agent because of its antitumor, antioxidant and antiproliferative effects. The cytotoxic, apoptotic and gene regulatory effects of both turmeric and curcumin were investigated in the MCF-7 human breast cancer carcinoma cell line and compared with the effects in MCF-10A human mammary epithelial cells. MCF-7 cells were more sensitive to turmeric and curcumin than MCF-10A cells. MCF-10A cells retained comparatively less curcumin in the medium than MCF- 7 cells after 24 h, thereby reducing the cytotoxic effect. Curcumin induced a significantly higher percentage of apoptosis in MCF-7 than MCF-10A cells at all doses. Microarray hybridization of Clonetech apoptotic arrays with labeled first-strand probes of total RNA was performed to identify and characterize the genes regulated by curcumin in tumor cells. Of the 214 apoptosis-associated genes in the array, the expression of 104 genes was altered by curcumin treatment. The gene expression was altered up to 14-fold levels in MCF-7 as compared to only up to 1.5-fold in the MCF-10A cell line by curcumin. Curcumin up-regulated (>3 fold) 22 genes and down-regulated (<3-fold) 17 genes at both 25 microg/ml and 50 microg/ml doses in the MCF-7 cell line. The up-regulated genes include HIAP1, CRAF1, TRAF6, CASP1, CASP2, CASP3, CASP4, HPRT, GADD45, MCL-1, NIP1, BCL2L2, TRAP3, GSTP1, DAXX, PIG11, UBC, PIG3, PCNA, CDC10, JNK1 and RBP2. The down-regulated genes were TRAIL, TNFR, AP13, IGFBP3, SARP3, PKB, IGFBP, CASP7, CASP9, TNFSF6, TRICK2A, CAS, TRAIL-R2, RATS1, hTRIP, TNFb and TNFRSF5. While a dose-dependent gene expression change was noticed in some genes, opposite regulatory effects were induced by different curcumin doses in three apoptotic genes. These results suggest that curcumin induces apoptosis in breast cancer cells by regulation of multiple signaling pathways, indicating its potential use for prevention and treatment of cancer.

Immune stimulating properties of a novel polysaccharide from the medicinal plant Tinospora cordifolia.

An alpha-D-glucan (RR1) composed of (1-->4) linked back bone and (1-->6) linked branches with a molecular mass of >550 kDa and exhibiting unique immune stimulating properties is isolated and characterized from the medicinal plant Tinospora cordifolia. This novel polysaccharide is noncytotoxic and nonproliferating to normal lymphocytes as well as tumor cell lines at 0-1000 microg/ml. It activated different subsets of the lymphocytes such as natural killer (NK) cells (331%), T cells (102%), and B cells (39%) at 100 microg/ml concentration. The significant activation of NK cells is associated with the dose-dependent killing of tumor cells by activated normal lymphocytes in a functional assay. Immune activation by RR1 in normal lymphocytes elicited the synthesis of interleukin (IL)-1beta (1080 pg/ml), IL-6 (21,833 pg/ml), IL-12 p70 (50.19 pg/ml), IL-12 p40 (918.23 pg/ml), IL-18 (27.47 pg/ml), IFN- gamma (90.16 pg/ml), tumor necrosis factor (TNF)-alpha (2225 pg/ml) and monocyte chemoattractant protein (MCP)-1 (2307 pg/ml) at 100 microg/ml concentration, while it did not induce the production of IL-2, IL-4, IL-10, interferon (IFN)-alpha and TNF-beta. The cytokine profile clearly demonstrates the Th1 pathway of T helper cell differentiation essential for cell mediated immunity, with a self-regulatory mechanism for the control of its overproduction. RR1 also activated the complements in the alternate pathway, demonstrated by a stepwise increase in C3a des Arg components. Incidentally, RR1 stimulation did not produce any oxidative stress or inducible nitric oxide synthase (iNOS) in the lymphocytes or any significant increase in nitric oxide production. The water solubility, high molecular mass, activation of lymphocytes especially NK cells, complement activation, Th1 pathway-associated cytokine profile, together with a low level of nitric oxide synthesis and absence of oxidative stress confer important immunoprotective potential to this novel alpha-D-glucan.

Tamoxifen modulation of etoposide cytotoxicity involves inhibition of protein kinase C activity and insulin-like growth factor II expression in brain tumor cells.

Tamoxifen, a non-steroidal anti-estrogen widely used against breast cancer, is also useful for treatment of other malignancies, due to its sensitizing effect on other chemotherapeutic agents and radiation. We have investigated the advantages of combining tamoxifen with one of the commonly used cancer chemotherapeutic drug, etoposide (VP-16) in brain tumor cell lines. While tamoxifen (10 microM) increased etoposide cytotoxicity 8.3-fold in the human glioma cell line (HTB-14), it increased etoposide cytotoxicity 47.5- and 40-fold in two primary cell lines established from pediatric medulloblastoma patients (MCH-BT-31 and MCH-BT-39), respectively. Similarly, in the pediatric ependymoma cell lines (MCH-BT-30 and MCH-BT-52), tamoxifen enhanced etoposide cytotoxicity 6- and 2.68-fold, respectively. CalcuSyn analysis of cytotoxicity data showed that tamoxifen and etoposide combinations were synergistic with combination index values ranging from 0.243 to 0.369 at IC50 level among different pediatric brain tumor cell lines. Tamoxifen is also cytotoxic at higher concentrations (> 20 microM) in brain tumor cells. To understand the mechanism underlying the tamoxifen modulation of etoposide cytotoxicity, we analyzed expression of P-glycoprotein (P-gp), insulin-like growth factor-I receptor (IGF-IR), IGF-I, IGF-II and estrogen receptor as well as protein kinase C (PKC) activity. While P-gp, IGF-IR and IGF-I were not affected, enhanced inhibition of PKC, and IGF-II were observed in brain tumor cells treated with tamoxifen and etoposide combination as compared to cells treated with either drug alone. Tamoxifen at 10 microM when combined with etoposide at 0-100 microM concentrations reduced PKC activity 77% compared to only 58% without tamoxifen. IGF-II expression decreased to 48.6% of the untreated control in the combination treatment as compared to 31.2% for etoposide alone and 26.2% for tamoxifen alone treatments. These results suggest that inhibitory effect of tamoxifen on brain tumor cells manifest through different mechanisms involving inhibition of targets such as PKC and IGF-II.

Acute lymphocytic leukemia in a child with Beckwith-Wiedemann syndrome.

Beckwith-Wiedemann syndrome (BWS) is an overgrowth syndrome characterized by neonatal hypoglycemia, abdominal wall defects, macroglossia, organomegaly, ear pits and creases, hemihypertrophy, and increased birthweight. Children with BWS have an increased risk of malignancy. The authors present the case of a 3-year-old boy diagnosed with both BWS and acute lymphocytic leukemia (ALL). This case report will elaborate on the possibilities as to how BWS and ALL may be associated due to abnormal genomic imprinting and IGF dysregulation.

Novel drug amooranin induces apoptosis through caspase activity in human breast carcinoma cell lines.

Amooranin (AMR) is a triterpene acid isolated from the stem bark of a tropical tree (Amoora rohituka) grown wild in India. A. rohituka stem bark is one of the components of a medicinal preparation used in the Indian Ayurvedic system of medicine for the treatment of human malignancies. We investigated the mechanism of cell death associated with AMR cytotoxicity in human mammary carcinoma MCF-7, multidrug resistant breast carcinoma MCF-7/TH and breast epithelial MCF-10A cell lines. AMR IC50 values ranged between 3.8-6.9 microg/ml among MCF-7, MCF-7/TH and MCF-10A cells. AMR induced oligonucleosome-sized DNA ladder formation characteristic of apoptosis when tumor cells were treated with 1-8 microg/ml AMR for 48 h. In situ cell death detection assay indicated that AMR caused 37.3-72.1% apoptotic cells in MCF-7, 32-48.7% in MCF-7/TH and 0-37.1% in MCF- 10A cells at 1-8 microg/ml concentrations. The induction of apoptosis in AMR treated cells was accompanied by the elevation of total caspase and caspase-8 activities. Flow cytometric analysis showed that AMR induced caspase-8 activation in 40.8-71% MCF-7, 28.5-43.2% MCF-7/TH and 4-32.8% MCF-10A cells at 1-8 microg/ml concentrations. Our results suggest that AMR is a novel drug having potential for clinical development against human malignancies.

Novel plant triterpenoid drug amooranin overcomes multidrug resistance in human leukemia and colon carcinoma cell lines.

Amooranin (AMR), a plant terpenoid, isolated from Amoora rohituka, was investigated for its ability to overcome multidrug resistance in human leukemia and colon carcinoma cell lines. AMR IC(50) values of multidrug-resistant leukemia (CEM/VLB) and colon carcinoma (SW620/Ad-300) cell lines were higher (1.9- and 6-fold) than parental sensitive cell lines (CEM and SW620). AMR induced G(2)+M phase-arrest during cell cycle traverse in leukemia and colon carcinoma cell lines and the percentage of cells in G(2)+M phase increased in a dose-dependent manner. Coincubation of tumor cells with both DOX and AMR reversed DOX resistance in 104-fold DOX-resistant CEM/VLB and 111-fold DOX-resistant SW620/Ad-300 cell lines with a dose modification factor of 50.9 and 99.6, respectively. Flow cytometric assay showed that AMR causes enhanced cellular DOX accumulation in a dose-dependent manner. AMR inhibits photolabeling of P-glycoprotein (P-gp) with [(3)H]-azidopine and the blocking effect enhanced with increasing concentrations of AMR. Our results show that AMR competitively inhibits P-gp-mediated DOX efflux, suggestive of a mechanism underlying the enhanced DOX accumulation and reversal of multidrug resistance by AMR.

Molecular studies in pediatric medulloblastomas.

Ten pediatric medulloblastoma patients were analyzed for DNA content, cell cycle, expression of drug resistance, apoptosis, cell proliferation, and N-myc genes to determine their prognostic significance. Medulloblastoma patients with progressive disease had fourth ventricle foraminal extension and larger tumors in the imaging studies. Patients with aneuploid tumors responded well to treatment regimens as compared with those with diploid tumors. Cell cycle analysis showed that the patients with progressive disease had a high S-phase fraction in the tumor cell population as compared with patients with favorable response to treatment. The correlation coefficients between Bcl-2 and MRP, Bcl-2 and Bax, p53 and p21, as well as Ki67 and PCNA were positive and significant, indicating their possible coregulated expression. The relationship between these markers indicates their relative and cumulative effect on cellular drug resistance, apoptosis, and/or cell proliferation in pediatric medulloblastomas.

Curcumin inhibits telomerase activity through human telomerase reverse transcritpase in MCF-7 breast cancer cell line.

The inhibitory effect of curcumin, the yellow-colored pigment from turmeric, on telomerase activity was analyzed in human mammary epithelial (MCF-10A) and breast cancer (MCF-7) cells. Telomerase activity in MCF-7 cells is 6.9-fold higher than that of human mammary epithelial cells. In MCF-7 cells, telomerase activity decreased with increasing concentrations of curcumin, inhibiting about 93.4% activity at 100 microM concentration. The inhibition of telomerase activity in MCF-7 cells may be due to down-regulation of hTERT expression. Increasing concentrations of curcumin caused a steady decrease in the level of hTERT mRNA in MCF-7 cells whereas the level of hTER and c-myc mRNAs remained the same. Our results suggest that curcumin inhibits telomerase activity by down-regulating hTERT expression in breast cancer cells and this down-regulation is not through the c-myc pathway.