Natural Products as Therapeutic Agents in Cancer Treatment

Cancer accounts for 25% of deaths in the United States, and brain tumors greatly contribute to this percentage. However, relative to other types of cancers, brain tumors prove difficult to treat because they are heterogeneous, highly proliferative, highly invasive, and resistant to the traditional cancer treatments of chemotherapy and radiotherapy. Past studies have shown that flavonoids and curcuminoids, two classes of compounds derived from natural sources, are effective in inhibiting the development and metastasis of breast and lung cancer cells. Research has also indicated that these compounds have potential for treating brain tumors. The purpose of this research is to further explore the potential of flavonoids as therapeutic options for the treatment of brain tumors. Specifically, flavonoids’ effect on cell proliferation, cell death, and tumor invasion will be studied. Another objective of this study is to identify the signaling mechanism by which flavonoids mediate their therapeutic effects on brain tumor cell lines. Three human brain tumor cell lines (U-1242, U-251, and U-87) will be studied. They will be treated with various flavonoids at increasing concentrations (10, 20, 40, and 80 µM). Cells will be counted following the trypan blue staining protocol. MTT assays and Western blot analyses will be used to assess cell proliferation. Cell death will be assessed with flow analyses and Western blot analyses. Unpaired t-tests will be run to compare treated and control cells at a 95% confidence interval. If necessary, one-way ANOVA with multiple comparisons will be used to compare multiple treatment groups and a control at a 95% confidence interval, and the Tukey post-hoc test will be utilized if appropriate. All statistical tests will be run in IBM SPSS 21®

The Antiproliferative and Apoptotic Effects of Apigenin on Glioblastoma Cells

OBJECTIVES: Glioblastoma (GBM) is highly proliferative, infiltrative, malignant and the most deadly form of brain tumour. The epidermal growth factor receptor (EGFR) is overexpressed, amplified and mutated in GBM and has been shown to play key and important roles in the proliferation, growth and survival of this tumour. The goal of our study was to investigate the antiproliferative, apoptotic and molecular effects of apigenin in GBM. METHODS: Proliferation and viability tests were carried out using the trypan blue exclusion, MTT and lactate dehydrogenase (LDH) assays. Flow cytometry was used to examine the effects of apigenin on the cell cycle check-points. In addition, we determined the effects of apigenin on EGFR-mediated signalling pathways by Western blot analyses. KEY FINDINGS: Our results showed that apigenin reduced cell viability and proliferation in a dose- and time-dependent manner while increasing cytotoxicity in GBM cells. Treatment with apigenin-induced is poly ADP-ribose polymerase (PARP) cleavage and caused cell cycle arrest at the G2M checkpoint. Furthermore, our data revealed that apigenin inhibited EGFR-mediated phosphorylation of mitogen-activated protein kinase (MAPK), AKT and mammalian target of rapamycin (mTOR) signalling pathways and attenuated the expression of Bcl-xL. CONCLUSION: Our results demonstrated that apigenin has potent inhibitory effects on pathways involved in GBM proliferation and survival and could potentially be used as a therapeutic agent for GBM

Luteolin Decreases EGFR-Mediated Cell Proliferation and Induces Apoptosis in Glioblastoma Cell Lines.

Glioblastomas are a subtype of gliomas, which are the most aggressive and deadly form of brain tumours. The epidermal growth factor receptor (EGFR) is over-expressed and amplified in glioblastomas. Luteolin is a common bioflavonoid found in a variety of fruits and vegetables. The aim of the present study was to explore the molecular and biological effects of luteolin on EGF-induced cell proliferation and the potential of luteolin to induce apoptosis in glioblastoma cells. In vitro cell viability assays demonstrated that luteolin decreased cell proliferation in the presence or absence of EGF. Immunoblots revealed that luteolin decreased the protein expression levels of phosphorylated Akt, mTOR, p70S6K, and MAPK in the presence of EGF. Furthermore, our results revealed the ability of luteolin to induce caspase and PARP cleavages in glioblastoma cells in addition to promoting cell cycle arrest. Our results demonstrated that luteolin has an inhibitory effect on downstream signalling molecules activated by EGFR, particularly the Akt and MAPK signalling pathways, and provided a rationale for further clinical investigation into the use of luteolin as a therapeutic molecule in the management of glioblastoma. This article is protected by copyright. All rights reserved

Evaluation of the Anticancer Activity of Bioactive Fraction G Extracted from \u3cem\u3ePavetta crassipes\u3c/em\u3e in Malignant Brain Tumor Cell Lines

Objective: Natural products have served as sources of lead compounds that are commonly used in the treatment of human diseases including cancer. Pavetta crassipes has been widely demonstrated to have ethnopharmacological potential in the management of malaria, gastrointestinal conditions, central nervous system behavioral disorders, hypertension, and cancer. The goal of our study was to evaluate the biological and molecular effects of Fraction G, obtained from the plant Pavetta crassipes, on glioblastoma invasive growth and survival. Methodology: The antiproliferative effects of Fraction G, obtained from Pavetta crassipes, was evaluated using the trypan blue exclusion, (3-(4, 5-Dimethylthiazol- 2yl)-2, 5-Diphenyltetrazolium Bromide; MTT), and lactate dehydrogenase (LDH) assays. Flow cytometry and Western blotting analyses were carried out to examine the effects of Fraction G on cell cycle check-points and its effects on epidermal growth factor receptor-mediated signaling of AKT and MAPK pathways. Results: In this paper, we report that the Fraction G obtained from the plant Pavetta crassipes induced a reduction in glioma cell viability and proliferation as well as induced an increase in apoptosis as evidenced by cleaved PARP, increased caspase 3/7 activity, and cell cycle arrest in the G0/G1 check point. Furthermore, we report that Fraction G inhibited the phosphorylation of AKT and MAPK following EGF treatment. Conclusion: Taken together, our results demonstrate that Fraction G has potent inhibitory effects on pathways involved in glioblastoma proliferation and survival

Eric Huseman

https://digitalcommons.cedarville.edu/white_coat_ceremony_gallery_2013/1011/thumbnail.jp