Steven J. Melnick

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

Abstract An α-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 μg/ml. It activated different subsets of the lymphocytes such as natural killer (NK) cells (331%), T cells (102%), and B cells (39%) at 100 μg/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)-1β (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- γ (90.16 pg/ml), tumor necrosis factor (TNF)-α (2225 pg/ml) and monocyte chemoattractant protein (MCP)-1 (2307 pg/ml) at 100 μg/ml concentration, while it did not induce the production of IL-2, IL-4, IL-10, interferon (IFN)-α and TNF-β. 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 α-d-glucan.

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.

Multidrug resistance in human tumors--molecular diagnosis and clinical significance.

BACKGROUND Multidrug resistance (MDR) of human tumors is one of the major reasons for the failure of chemotherapy in refractory cancer patients. MDR can be intrinsic or acquired, depending on the time of its occurrence, either at diagnosis or during chemotherapy. Molecular investigations in MDR during the last two decades have resulted in the isolation and characterization of genes coding for P-glycoprotein, multidrug resistance-associated protein, lung resistance-related protein, drug resistance-associated protein, breast cancer resistance protein, and adenosine triphosphate-binding cassette protein. Several molecular probes, primer pairs, and monoclonal antibodies have been developed over these years to quantify the regulation and expression of these drug resistance markers in tumor cells. Methodologies have also been standardized to estimate the gene amplification, mRNA and protein expression, and functionality of drug resistance proteins in clinical specimens from cancer patients. METHODS AND RESULTS This review describes these drug resistance genes and techniques for detection and quantification of their expression and function. CONCLUSIONS Because these markers have clinical significance and usefulness, currently available technology warrants the application of these markers in clinical oncology.

Children's Oncology Group (COG) Nutrition Committee

The Childrens Oncology Group (COG) Nutrition Committee was established to further the knowledge of nutrition in children with cancer by education and the conduct of clinical trials. A survey of COG institutions revealed lack of conformity in evaluation and categorization of nutritional status, and criteria for nutritional intervention. The Committee subsequently established specific categories of malnutrition (Underweight and Overweight) based on ideal body weight or body mass index. An algorithm was developed as a guideline for nutritional intervention as well as references and resources for determining estimated needs. The Committee embarked on concepts for clinical trials of nutritional interventions. The first pilot study, evaluating the feasibility of using an immunoneutraceutical precursor for glutathione production, has been completed. This study showed weight gain and improvement in glutathione status. A pilot trial of proactive enteral feeding for patients at high risk of malnutrition has commenced. The Committee believes that nutrition is relevant to all aspects of cancer control. The paucity of nutritional investigation in children with cancer needs to be rectified. Pediatr Blood Cancer

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 IC50 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 G2+M phase‐arrest during cell cycle traverse in leukemia and colon carcinoma cell lines and the percentage of cells in G2+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 [3H]‐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.

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 µg/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 1–8µg/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 1–8µg/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 µg/ml concentrations. Our results suggest that AMR is a novel drug having potential for clinical development against human malignancies.

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 uM) 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 μM) 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 μM when combined with etoposide at 0–100 μM 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.

Activation of Human T-Helper/Inducer Cell, T-Cytotoxic Cell, B-Cell, and Natural Killer (NK)-Cells and induction of Natural Killer Cell Activity against K562 Chronic Myeloid Leukemia Cells with Modified Citrus Pectin

BackgroundModified citrus pectin (MCP) is known for its anti-cancer effects and its ability to be absorbed and circulated in the human body. In this report we tested the ability of MCP to induce the activation of human blood lymphocyte subsets like T, B and NK-cells.MethodsMCP treated human blood samples were incubated with specific antibody combinations and analyzed in a flow cytometer using a 3-color protocol. To test functionality of the activated NK-cells, isolated normal lymphocytes were treated with increasing concentrations of MCP. Log-phase PKH26-labeled K562 leukemic cells were added to the lymphocytes and incubated for 4 h. The mixture was stained with FITC-labeled active form of caspase 3 antibody and analyzed by a 2-color flow cytometry protocol. The percentage of K562 cells positive for PKH26 and FITC were calculated as the dead cells induced by NK-cells. Monosaccharide analysis of the MCP was performed by high-performance anion-exchange chromatography with pulse amperometric detection (HPAEC-PAD).ResultsMCP activated T-cytotoxic cells and B-cell in a dose-dependent manner, and induced significant dose-dependent activation of NK-cells. MCP-activated NK-cells demonstrated functionality in inducing cancer cell death. MCP consisted of oligogalacturonic acids with some containing 4,5-unsaturated non-reducing ends.ConclusionsMCP has immunostimulatory properties in human blood samples, including the activation of functional NK cells against K562 leukemic cells in culture. Unsaturated oligogalacturonic acids appear to be the immunostimulatory carbohydrates in MCP.

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 IC50 value of 2.9 μg/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 μg/ml to 60.5% at 100 μg/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 μg/ml to 59.2% at 100 μg/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‐XL 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.

Neoplasm as a cause of brachial plexus palsy in neonates

Two patients with neonatal onset of arm weakness resulting from neoplastic involvement of the brachial plexus who were initially considered to have obstetric brachial plexus palsies are reported. The first patient was a 7-day-old female who presented with a left supraclavicular mass that was first detected at 2 days of age and left proximal arm weakness. The weakness involved the whole arm within 3 days. The mass was a malignant rhabdoid tumor. The second patient was a 28-month-old male who presented with slowly progressive right arm weakness, which began at 3 weeks of age, and episodes of scratch marks on the arm that began at 4 months of age. Magnetic resonance imaging revealed a plexiform neurofibroma of the brachial plexus. The features that are suggestive of a brachial plexus palsy caused by a neoplasm rather than of obstetric brachial plexus palsy include the following: the onset of weakness after the first day of age, with a progressive course; a history of a normal delivery and birth weight; the absence of signs of a traumatic injury or injuries; the appearance before 7 days of age of a growing supraclavicular mass without radiographic evidence of a clavicular fracture; and recurrent scratch marks on the weak arm.