The Effect of Biotinylated PAMAM G3 Dendrimers Conjugated with COX-2 Inhibitor (celecoxib) and PPARγ Agonist (Fmoc-L-Leucine) on Human Normal Fibroblasts, Immortalized Keratinocytes and Glioma Cells in Vitro

Abstract

Glioblastoma multiforme (GBM) is the most malignant type of central nervous system tumor that is resistant to all currently used forms of therapy. Thus, more effective GBM treatment strategies are being investigated, including combined therapies with drugs that may cross the blood brain barrier (BBB). Another important issue considers the decrease of deleterious side effects of therapy. It has been shown that nanocarrier conjugates with biotin can penetrate BBB. In this study, biotinylated PAMAM G3 dendrimers substituted with the recognized anticancer agents cyclooxygenase-2 (COX-2) inhibitor celecoxib and peroxisome proliferator-activated receptor γ (PPARγ) agonist Fmoc-L-Leucine (G3-BCL) were tested in vitro on human cell lines with different p53 status: glioblastoma (U-118 MG), normal fibroblasts (BJ) and immortalized keratinocytes (HaCaT). G3-BCL penetrated efficiently into the lysosomal and mitochondrial compartments of U-118 MG cells and induced death of U-118 MG cells via apoptosis and inhibited proliferation and migration at low IC50 = 1.25 µM concentration, considerably lower than either drug applied alone. Comparison of the effects of G3-BCL on expression of COX-2 and PPARγ protein and PGE2 production of three different investigated cell line phenotypes revealed that the anti-glioma effect of the conjugate was realized by other mechanisms other than influencing PPAR-γ expression and regardless of p53 cell status, it was dependent on COX-2 protein level and high PGE2 production. Similar G3-BCL cytotoxicity was seen in normal fibroblasts (IC50 = 1.29 µM) and higher resistance in HaCaT cells (IC50 = 4.49 µM). Thus, G3-BCL might be a good candidate for the targeted, local glioma therapy with limited site effects.

<p>PAMAM Dendrimer Nanomolecules Utilized as Drug Delivery Systems for Potential Treatment of Glioblastoma: A Systematic Review</p>

“…The dendrimer complex was also found to localize primarily in the lysosome and mitochondria of both control and glioma cell lines with subsequent increased caspase 3/7 activity which peaked at 2 μM of G3-BCL administration, indicating apoptosis. 79 These results are notable with respect to a novel targeting substrate in the treatment of glioblastoma and highlight the utility of dendrimers with multiple conjugated therapeutic agents. Looking ahead, in vivo investigations into the utility of such constructs would further potentiate the promising outlook of such constructs.…”

“…77 Like Wu and colleagues (2018), Uram and colleagues (2018, 2019) investigated two upregulated tumor protein targets for developing an appropriate inhibitor and cancer cell-targeting dendrimer. [77][78][79] Specifically, various cancer cell lines, including GB, are known to overexpress cyclooxygenase-2 (COX-2) and peroxisome proliferator-activated receptor ɣ (PPARɣ) proteins. 78 COX-2 has been shown to promote proliferation, migration, and invasion of cancer cells, resist apoptosis, and stimulate angiogenesis.…”

“…Uram and colleagues (2018) achieved this by utilizing the COX-2 inhibitor, celecoxib, and PPARɣ agonist, Fmoc-L -Leucine, to conjugate with biotinylated G3 PAMAM dendrimers (G3-BCL). 78,79 In their initial experiments, variable quantities of celecoxib were used per dendrimer construct for administration to glioblastoma and squamous cell carcinoma cell lines. The highest cytotoxicity in U118MG cancer cells was determined to be with a 1:1 combination of Fmoc-L -Leucine and celecoxib-conjugated dendrimer when compared to individual (ie, Fmoc-L -Leucine or celecoxib alone) drugconjugated dendrimers.…”

The molecular mechanisms of celecoxib in tumor development

“… [100] Therefore, celecoxib can inhibit the transduction of Wnt/β-catenin signaling pathway through COX-2 dependent and non-dependent mechanisms and has anti-cancer effects. [101] …”

Dendrimers as Modulators of Brain Cells

“…Similar to the principle of nanoparticle entry through BBB, the tumor targetability and cell uptake of nanodelivery systems are accomplished by ligand–receptor interactions. Uram et al employed biotinylated PAMAM G3 dendrimers and studied the synergistic effects by the loaded cycolxygenase-2 (COX-2) inhibitor, celecoxib, and the peroxisome proliferator-activated receptor γ (PPAR γ) agonist, Fmoc-L-leucine [ 106 , 107 ]. The nanoparticles obtained cell type-dependent cytotoxicity owing to the varied basal levels of biotin receptors, COX-2 and PPAR γ upon biotin-specific uptake by tumor cells and healthy controls.…”