Cationic Poly(amidoamine) Dendrimer Induces Lysosomal Apoptotic Pathway at Therapeutically Relevant Concentrations

Thomas, Thommey P.; Majoros, István J.; Kotlyar, Alina; Mullen, Douglas G.; Holl, Mark M. Banaszak; Baker, James R.

doi:10.1021/bm900683r

Cited by 112 publications

(101 citation statements)

References 59 publications

(201 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As shown in Table 2, the LC 50 of cationic PAMAM dendrimers increased from 2 ppm for G3 PAMAM-amine to 18 ppm for G6 PAMAM-amine dendrimers. Thiophosphoryl dendrimers induced no significant morbidity or mortality at any concentration tested (LC 50 . 250 ppm).…”

Section: Generation (Size) Effectsmentioning

confidence: 94%

“…49 Furthermore, evidence suggests cationic PAMAM dendrimers induce lyosomal instability through alkalinization. 50 The instability is likely due to a combination of both an increase in pH as well as a lipid bilayer instability through nanoscale hole formation. 19 Smaller PAMAM dendrimers (G1-G5) have been shown to prefer water (plasma), whereas higher generation (G6 and G8) dendrimers were demonstrated to partition at the octanol/water interface.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Comparative toxicological assessment of PAMAM and thiophosphoryl dendrimers using embryonic zebrafish

Pryor¹,

Harper²,

Harper³

2014

IJN

View full text Add to dashboard Cite

Dendrimers are well-defined, polymeric nanomaterials currently being investigated for biomedical applications such as medical imaging, gene therapy, and tissue targeted therapy. Initially, higher generation (size) dendrimers were of interest because of their drug carrying capacity. However, increased generation was associated with increased toxicity. The majority of studies exploring dendrimer toxicity have focused on a small range of materials using cell culture methods, with few studies investigating the toxicity across a wide range of materials in vivo. The objective of the present study was to investigate the role of surface charge and generation in dendrimer toxicity using embryonic zebrafish ( Danio rerio ) as a model vertebrate. Due to the generational and charge effects observed at the cellular level, higher generation cationic dendrimers were hypothesized to be more toxic than lower generation anionic or neutral dendrimers with the same core composition. Polyamidoamine (PAMAM) dendrimers elicited significant morbidity and mortality as generation was decreased. No significant adverse effects were observed from the suite of thiophosphoryl dendrimers studied. Exposure to ≥50 ppm cationic PAMAM dendrimers G3-amine, G4-amine, G5-amine, and G6-amine caused 100% mortality by 24 hours post-fertilization. Cationic PAMAM G6-amine at 250 ppm was found to be statistically more toxic than both neutral PAMAM G6-amidoethanol and anionic PAMAM G6-succinamic acid at the same concentration. The toxicity observed within the suite of varying dendrimers provides evidence that surface charge may be the best indicator of dendrimer toxicity. Dendrimer class and generation are other potential contributors to the toxicity of dendrimers. Further studies are required to better understand the relative role each plays in driving the toxicity of dendrimers. To the best of our knowledge, this is the first in vivo study to address such a broad range of dendrimers.

show abstract

Section: Generation (Size) Effectsmentioning

confidence: 94%

mentioning

confidence: 99%

Comparative toxicological assessment of PAMAM and thiophosphoryl dendrimers using embryonic zebrafish

Pryor¹,

Harper²,

Harper³

2014

IJN

View full text Add to dashboard Cite

show abstract

“…Because of this, titratable alkalinizing polycations, such as polyethylenimine, 16 chitosan, 17 and polyamidoamine dendrimers, 18 are used to induce endosomal/lysosomal disruption by the proton sponge mechanism. 16,[19][20][21] In this sense, some authors have found the uptake of nanoparticles by clathrindependent endocytosis to be better than by clathrinindependent endocytosis for effective transfection. 22 Other authors have found caveolin mediated endocytosis better suited than clathrindependent endocytosis for successful transfection because this pathway is thought to evade acid degradation.…”

Section: Introductionmentioning

confidence: 99%

Uptake and intracellular traffic of siRNA dendriplexes in glioblastoma cells and macrophages

Perez¹,

Cosaka²,

Romero³

et al. 2011

IJN

View full text Add to dashboard Cite

Background: Gene silencing using small interfering RNA (siRNA) is a promising new therapeutic approach for glioblastoma. The endocytic uptake and delivery of siRNA to intra cellular compartments could be enhanced by complexation with polyamidoamine dendrimers. In the present work, the uptake mechanisms and intracellular traffic of siRNA/generation 7 dendrimer complexes (siRNA dendriplexes) were screened in T98G glioblastoma and J774 macrophages. Methods: The effect of a set of chemical inhibitors of endocytosis on the uptake and silenc ing capacity of dendriplexes was determined by flow cytometry. Colocalization of fluorescent dendriplexes with endocytic markers and occurrence of intracellular dissociation were assessed by confocal laser scanning microscopy. Results: Uptake of siRNA dendriplexes by T98G cells was reduced by methylβcyclodextrin, and genistein, and cytochalasine D, silencing activity was reduced by genistein; dendriplexes colocalized with cholera toxin subunit B. Therefore, caveolindependent endocytosis was involved both in the uptake and silencing activity of siRNA dendriplexes. On the other hand, uptake of siRNA dendriplexes by J774 cells was reduced by methylβcyclodextrin, genistein, chlorpromazine, chloroquine, cytochalasine D, and nocodazole, the silencing activity was not affected by chlorpromazine, genistein or chloroquine, and dendriplexes colocalized with transferrin and cholera toxin subunit B. Thus, both clathrindependent and caveolindependent endocytosis mediated the uptake and silencing activity of the siRNA dendriplexes. SiRNA dendriplexes were internalized at higher rates by T98G but induced lower silencing than in J774 cells. SiRNA dendriplexes showed relatively slow dissociation kinetics, and their escape towards the cytosol was not mediated by acidification independently of the uptake pathway. Conclusion: The extent of cellular uptake of siRNA dendriplexes was inversely related to their silencing activity. The higher silencing activity of siRNA dendriplexes in J774 cells could be ascribed to the contribution of clathrindependent and caveolindependent endocytosis vs only caveolindependent endocytosis in T98G cells.

show abstract

“…8,56,57 Lysosomal membrane disturbance and accumulation of nondegradable and slowly degrading dendrimers in lysosomes create other mechanisms of cytotoxicity. 8,58 Further studies are needed to recognize and verify the molecular mechanisms of these findings.…”

mentioning

confidence: 99%

In vitro cytotoxicity of the ternary PAMAM G3–pyridoxal–biotin bioconjugate

Uram

Szuster

Gargasz

et al. 2013

IJN

View full text Add to dashboard Cite

A third-generation polyamidoamine dendrimer (PAMAM G3) was used as a macromolecular carrier for pyridoxal and biotin. The binary covalent bioconjugate of G3, with nine molecules of biotin per one molecule of G3 (G3 9B ), and the ternary covalent bioconjugate of G3, with nine biotin and ten pyridoxal molecules (G3 9B10P ), were synthesized. The biotin and pyridoxal residues of the bioconjugate were available for carboxylase and transaminase enzymes, as demonstrated in the conversion of pyruvate to oxaloacetate and alanine to pyruvate, respectively, by in vitro monitoring of the reactions, using 1 H nuclear magnetic resonance spectroscopy. The toxicity of the ternary bioconjugate (BC-PAMAM) was studied in vitro on BJ human normal skin fibroblasts and human squamous cell carcinoma (SCC-15) cell cultures in comparison with PAMAM G3, using three cytotoxicity assays (XTT, neutral red, and crystal violet) and an estimation of apoptosis by confocal microscopy detection. The tests have shown that BC-PAMAM has significantly lower cytotoxicity compared with PAMAM. Nonconjugated PAMAM was not cytotoxic at concentrations up to 5 μM (NR) and 10 μM (XTT), and BC-PAMAM was not cytotoxic up to 50 μM (both assays) for both cell lines. It has been also found that normal fibroblasts were more sensitive than SCC to both PAMAM and BC-PAMAM. The effect of PAMAM and BC-PAMAM on the initiation of apoptosis (PAMAM in fibroblasts at 5 μM and BC-PAMAM at 10 μM in both cell lines) corresponded with cytotoxicity assays for both cell lines. We concluded that normal fibroblasts are more sensitive to the cytotoxic effects of the PAMAM G3 dendrimer and that modification of its surface cationic groups by substitution with biologically active molecules significantly decreases that effect, confirming that PAMAM G3 is a useful candidate as a carrier for active biocompound delivery.

show abstract

Cationic Poly(amidoamine) Dendrimer Induces Lysosomal Apoptotic Pathway at Therapeutically Relevant Concentrations

Cited by 112 publications

References 59 publications

Comparative toxicological assessment of PAMAM and thiophosphoryl dendrimers using embryonic zebrafish

Comparative toxicological assessment of PAMAM and thiophosphoryl dendrimers using embryonic zebrafish

Uptake and intracellular traffic of siRNA dendriplexes in glioblastoma cells and macrophages

In vitro cytotoxicity of the ternary PAMAM G3–pyridoxal–biotin bioconjugate

Contact Info

Product

Resources

About

Cationic Poly(amidoamine) Dendrimer Induces Lysosomal Apoptotic Pathway at Therapeutically Relevant Concentrations

Cited by 112 publications

References 59 publications

Comparative toxicological assessment of PAMAM and thiophosphoryl dendrimers using embryonic zebrafish

Comparative toxicological assessment of PAMAM and thiophosphoryl dendrimers using embryonic zebrafish

Uptake and intracellular traffic of siRNA dendriplexes in glioblastoma cells and macrophages

In vitro cytotoxicity of the ternary PAMAM G3&ndash;pyridoxal&ndash;biotin bioconjugate

Contact Info

Product

Resources

About

In vitro cytotoxicity of the ternary PAMAM G3–pyridoxal–biotin bioconjugate