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Curcuminoids Supress Cell Proliferation of Glioblastoma by Down‐regulation of CXCR4 Signaling Pathway
Author(s) -
Shivachar Amruthesh C.,
Nnamdiebere Joseph Ekeada,
Jordan Bryan C.,
Selvam Chelliah,
Mathews Omana P,
Ranganna Kasturi
Publication year - 2017
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.31.1_supplement.lb530
Subject(s) - propidium iodide , chemistry , apoptosis , programmed cell death , cell growth , fluorescence microscope , glioblastoma , cancer research , fluorescence , biology , biochemistry , physics , quantum mechanics
Glioblastoma multiforme is one of the glial‐derived malignant primary brain tumors in adults with a poor prognosis. The current average survival period still remains between 14–16 months despite various treatment modalities. The robust tumor progression is mainly attributed to its pro‐angiogenic and anti‐hypoxic targets that many current chemotherapeutics may miss. Curcumin (#1) is a plant derived dietary constituent, and has been shown to play a role in preventing many cancers. Here we investigated for the first time the potencies and the molecular mechanisms of action of #1 and its three pyrazole analogs (#7, #20, and #32) that were prepared through an acid catalyzed condensation with various hydrazine derivatives. Heterocyclic pyrazole modification introduces conformational constraint that is beneficial for improving potency and in vivo chemical stability for curcumin analogs. Cultures of grade IV glioblastoma multiforme (GBM) cells (10,000 cells/cm 2 ) in 24‐well plates were treated with various concentrations (0.01–10micrMole) of #1, #7, #20 or #32 for 24 hr. along with vehicle controls. Cell viability/toxicity was assessed using the fluorescent dyes Hoechst 33342 (1 mg/ml, 20 min at 37°C), which stains DNA of both living and dead cells and propidium iodide (PI; 5 mg/ml, 5 min, 37°C), which stains the DNA of cells with disrupted membranes. The cell death was calculated [pink cells × 100/total cells] from 3–5 non‐overlapping microscopic fields in an Olympus IX81 inverted fluorescent microscope: dead cells are double stained (pink), while viable ones remained blue and were quantified using Prism Graph Pad software. The cell proliferation was measured by the uptake of BrDU by immunofluorescent method. In the sister cultures, the effect of these analogs on the expression of chemokine receptor 4 (CXCR4) that is known to affect tumor progression and metastasis in these cells was measured by western blotting analyses. Our results show that the tested analogs dose‐dependently decreased cell viability and inhibited cell proliferation in the order #32> #20> #7> #1, suggesting that heterocyclic pyrazole modification increased the potency of the parent compound #1. Additionally, we noted that #1 and its pyrazole analogs significantly down‐regulated the expression of CXCR4 over vehicle‐treated controls. Thus our preliminary results demonstrate that curcuminoids may suppress cell proliferation of GBM by down‐regulation of CXCR4 signaling pathway. Support or Funding Information This work was supported, in part, by an Institutional seed grant (ACS), and by NIH‐RCMI‐Program Molecular Biology Core Facility (KR).