Effect of Thuja occidentalis and its polysaccharide on cell-mediated immune responses and cytokine levels of metastatic tumor-bearing animals.

CONTEXT: Tumor microenvironment induces an active immune tolerance and escapes immune surveillance. In order to achieve an effective antitumor immune response, appropriately activated immune cells should maintain their antitumor activity to overcome the immune suppressive tumor microenvironment. OBJECTIVES: This study focuses on the effect of Thuja occidentalis L. (Cupressaceae) extract and its polysaccharide (TPS) on cell-mediated immune response (CMI) in metastasis bearing mice. MATERIALS AND METHODS: Metastasis was induced by injecting B16F-10 melanoma cells in mice through the tail vein and effector mechanisms of CMI was studied by analyzing cytotoxic T-lymphocyte (CTL) activity, natural killer (NK) cell activity, antibody-dependent cell-mediated cytotoxicity (ADCC) and antibody-dependent complement-mediated cytotoxicity (ACC). The effect of T. occidentalis and TPS on pro-inflammatory cytokines and tissue inhibitor matrix metalloproteinases (TIMP) levels were also analyzed. RESULTS AND DISCUSSION: Administration of T. occidentalis and TPS enhanced the NK cell activity, ADCC and ACC much earlier than the control tumor-bearing animals. T. occidentalis and TPS were also found to decrease the elevated level of pro-inflammatory cytokines such as interleukin (IL)-1ß, IL-6, GM-CSF and tumor necrosis factor (TNF)-α in the serum of metastatic tumor-bearing animals. The level of antitumor factors such as IL-2 and TIMP was elevated by the treatment with T. occidentalis and TPS in the serum, which was lowered in the untreated tumor-bearing animals. CONCLUSION: This study clearly suggests that T. occidentalis and TPS effectively stimulate cell-mediated immune system and decrease pro-inflammatory cytokines, thereby inhibiting metastasis of tumor cells.

Inhibition of chemically induced carcinogenesis by drugs used in homeopathic medicine.

Homeopathy is considered as one modality for cancer therapy. However, there are only very few clinical reports on the activity of the drugs, as well as in experimental animals. Presently we have evaluated the inhibitory effects of potentized homeopathic preparations against N'-nitrosodiethylamine (NDEA) induced hepatocellular carcinoma in rats as well as 3-methylcholanthrene-induced sarcomas in mice. We have used Ruta, Hydrastis, Lycopodium and Thuja, which are commonly employed in homeopathy for treating cancer. Administration of NDEA in rats resulted in tumor induction in the liver and elevated marker enzymes such as gamma-glutamyl transpeptidase, glutamate pyruvate transaminase, glutamate oxaloacetate transaminase and alkaline phosphatase in the serum and in liver. Concomitant administration of homeopathic drugs retarded the tumor growth and significantly reduced the elevated marker enzymes level as revealed by morphological, biochemical and histopathological evaluation. Out of the four drugs studied, Ruta 200c showed maximum inhibition of liver tumor development. Ruta 200c and phosphorus 1M were found to reduce the incidence of 3-methylcholanthrene-induced sarcomas and also increase the life span of mice harboring the tumours. These studies demonstrate that homeopathic drugs, at ultra low doses, may be able to decrease tumor induction by carcinogen administration. At present we do not know the mechanisms of action of these drugs useful against carcinogenesis.

Piper longum inhibits VEGF and proinflammatory cytokines and tumor-induced angiogenesis in C57BL/6 mice.

The antiangiogenic activity of Piper longum was studied using in vivo as well as in vitro models. In vivo, antiangiogenic activity was studied using B16F-10 melanoma cell-induced capillary formation in C57BL/6 mice. Intraperitoneal administration of the extract (10 mg/dose/animal) significantly inhibited (50.6%) the number of tumor-directed capillaries induced by injecting B16F-10 melanoma cells on the ventral side of C57BL/6 mice. The cytokine profile in the serum of these animals showed a drastically increased level of proinflammatory cytokines such as IL-1beta, IL-6, TNF-alpha, GM-CSF and the direct endothelial cell proliferating agent, VEGF. Administration of the methanolic extract of P. longum could differentially regulate the level of these cytokines. The level of IL-2 and tissue inhibitor of metalloprotease-1 (TIMP-1) was increased significantly when the angiogenesis-induced animals were treated with the extract. The extract of P. longum at non-toxic concentrations (10 microg/ml, 5 microg/ml, 1 microg/ml) inhibited the VEGF-induced vessel sprouting in rat aortic ring assay. Moreover, P. longum was able to inhibit the VEGF-induced proliferation, cell migration and capillary-like tube formation of primary cultured human endothelial cells. Hence, the observed antiangiogenic activity of the plant P. longum is related to the regulation of these cytokines and growth factors in angiogenesis-induced animals.

Protective effect of Thuja occidentalis against radiation-induced toxicity in mice.

The effect of Thuja occidentalis against damage induced by gamma radiation was studied. Whole-body exposure of Swiss albino mice to gamma-rays (6 Gy) reduced the total white blood cell count to 1900 cells/mm(3) on the third day, which was elevated to 2050 cells/mm(3) by the administration of alcoholic extract ofT occidentalis (5 mg/dose/animal, intraperitoneally). Six animals from each group were killed after 2, 7, and 11 days of irradiation to detect the bone marrow cellularity and radiation-induced toxicity. The number of bone marrow cells and alpha-esterase positive cells in control animals after 11 days was reduced to 12.2 x 10(6) cells/femur and 693.5/4000 cells, respectively. In T occidentalis-treated animals, bone marrow cellularity was increased to 16.9 x 10(6) cells/femur and alpha-esterase positive cells were 940/4000 cells, a nearly normal level. Alcoholic extract of T occidentalis reduced the elevated levels of GPT and alkaline phosphatase in liver and serum after irradiation. The lipid peroxidation levels were also lowered in the irradiated animals treated with the Thuja extract.

Expression of vascular endothelial growth factor (VEGF) and VEGF receptors in tumor angiogenesis and malignancies.

Angiogenesis is a process by which new blood vessels are formed from preexisting vessels. New blood vessel formation by angiogenesis involves the degradation of extra-cellular matrix combined with sprouting and migration of endothelial cells from preexisting capillaries. Solid tumors consist of several components, including normal and stromal cells, extracellular matrix, and vasculature. To grow and metastasize, tumors must stimulate the development of new vasculature through angiogenesis. Vascular endothelial growth factor (VEGF) is a potent angiogenic peptide with biologic effects that include regulation of hematopoietic stem cell development, extracellular matrix remodeling, and inflammatory cytokine regeneration. VEGF is both a vascular growth factor and a vascular permeability factor. Its expression can upregulate several proangiogenic and prometa-static molecules. As a central mediator of angiogenesis, VEGF has emerged as an important target for antiangiogenic therapy. In this review, the authors describe the essential characteristics of VEGF and the VEGF family of ligands and their receptors. They also provide an overview of the central role of VEGF in physiologic and pathologic angiogenesis, directly or indirectly. This review sheds light on the importance of VEGF-targeted antiangiogenic therapy based on the monoclonal antibodies against VEGF, small interfering RNA, and therapy directed against VEGF-VEGFR kinase. It also gives a brief overview of the natural products or dietary compounds that could be used as antiangiogenic agents. Therapeutic inhibition of vessel formation could be best suited to preventive strategies aimed at the suppression of angiogenesis in primary tumors in subjects at risk or of micrometastases after surgical removal of primary tumor.

Protective effect of Piper longum fruit ethanolic extract on radiation induced damages in mice: a preliminary study.

The radioprotective property of an ethanolic extract of Piper longum fruits (EEPLF) was investigated in Swiss mice. The white blood cell (WBC) count in irradiated control mice was drastically reduced to 1900 cells/mm3 on third day but in treated animals the count was 2783.3 cells/mm3. The number of bone marrow cells and alpha-esterase positive cells was also enhanced by the EEPLF administration (16.7 x 10(6) cells/femur and 946.5/4000 cells, respectively) when compared to the radiation exposed control animals (12.2 x 10(6) cells/femur and 693.5/4000 cells, respectively). EEPLF reduced the elevated levels of glutathione pyruvate transaminase (GPT), alkaline phosphatase (ALP), and lipid peroxidation (LPO) in liver and serum of radiation treated animals. The extract administration also increased the reduced glutathione (GSH) production to offer the radioprotection.

Immunomodulatory and antitumor activity of Piper longum Linn. and piperine.

Alcoholic extract of the fruits of the plant Piper longum and its component piperine was studied for their immunomodulatory and antitumor activity. Alcoholic extract of the fruits was 100% toxic at a concentration of 500 microg/ml to Dalton's lymphoma ascites (DLA) cells and 250 microg/ml to Ehrlich ascites carcinoma (EAC) cells. Piperine was found to be cytotoxic towards DLA and EAC cells at a concentration of 250 microg/ml. Alcoholic extract and piperine was also found to produce cytotoxicity towards L929 cells in culture at a concentration of 100 and 50 microg/ml, respectively. Administration of alcoholic extract of Piper longum (10 mg/dose/animal) as well as piperine (1.14 mg/dose/animal) could inhibit the solid tumor development in mice induced with DLA cells and increase the life span of mice bearing Ehrlich ascites carcinoma tumor to 37.3 and 58.8%, respectively. Administration of Piper longum extract and piperine increased the total WBC count to 142.8 and 138.9%, respectively, in Balb/c mice. The number of plaque forming cells also enhanced significantly by the administration of the extract (100.3%) and piperine (71.4%) on 5th day after immunization. Bone marrow cellularity and alpha-esterase positive cells were also increased by the administration of Piper longum extract and piperine.

IRL-1620, an endothelin-B receptor agonist, enhanced radiation induced reduction in tumor volume in Dalton's Lymphoma Ascites tumor model.

ETB receptor agonist, IRL-1620 (or SPI-1620) presently in US Phase 1 clinical trial, has been demonstrated to selectively and transiently increase tumor blood flow. The present study was conducted to determine the effect of IRL-1620 on radiation therapy in tumor bearing mice inoculated with Dalton's Lymphoma Ascites cells. Tumors were allowed to grow for 30 days to a size of 1.10-1.29 cm3 before starting the treatment. The animals with or without IRL-1620 treatment were exposed to radiation (4 Gy/dose) on every alternate day for a total of 5 doses. Tumor volume was determined twice every week till the end of study. Radiation alone did not affect the tumor volume; however, animals treated with IRL-1620 followed by radiation produced a significant (64%) reduction in tumor volume. Survival of mice improved from 0/10 at 56 days after tumor inoculation in vehicle plus radiation group to 6/10 at 70 days in IRL-1620 (9 nmol/kg) plus radiation group. It is concluded that IRL-1620 improves the efficacy of radiation treatment in tumor bearing mice. (These findings have been earlier presented as an abstract ).

A preliminary study on antimetastatic activity of Thuja occidentalis L. in mice model.

The effect of Thuja occidentalis extract on the inhibition of lung metastasis induced by B16F-10 melanoma cells was studied in C57BL/6 mice. The extract was administered by three different modalities. A remarkable reduction in tumor-nodule formation was shown by simultaneous (74.4%) and prophylactic (71.5%) mode of administration. The effect was comparatively low in drug administration after tumor development (60.2%). Increased lung collagen hydroxyproline (21.13 microg/mg protein) in the metastasized lungs of control animals compared with normal animals (0.98 microg/mg protein) was significantly reduced in Thuja-treated animals. The elevated level of uronic acid (349.5 microg/100 mg tissue) and hexosamine contents in metastatic control animals was significantly reduced in the animals treated with alcoholic extract of Thuja. Similarly the elevated levels of serum sialic acid and serum gamma glutamyl transpeptidase activity in the untreated control animals was significantly reduced in the animals treated with the extract of Thuja. The lifespan of the Thuja treated animals also was seen to be significantly increased.