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A liposomal formulation of the synthetic curcumin analog EF24 (Lipo-EF24) inhibits pancreatic cancer progression: towards future combination therapies.

Bisht S, Schlesinger M, Rupp A, Schubert R, Nolting J, Wenzel J, Holdenrieder S, Brossart P, Bendas G, Feldmann G - J Nanobiotechnology (2016)

Bottom Line: Lipo-EF24 potently suppressed NF-kappaB nuclear translocation by inhibiting phosphorylation and subsequent degradation of its inhibitor I-kappa-B-alpha.In vivo, synergistic tumor growth inhibition was observed in MIAPaCa xenografts when Lipo-EF24 was given in combination with the standard-of-care cytotoxic agent gemcitabine.In line with in vitro observations, western blot analysis revealed decreased phosphorylation of I-kappa-B-alpha in excised Lipo-EF24-treated xenograft tumor tissues.

View Article: PubMed Central - PubMed

Affiliation: Department of Internal Medicine 3, Center of Integrated Oncology (CIO) Cologne-Bonn, University Hospital of Bonn, Sigmund-Freud-Str. 25, 53127, Bonn, Germany.

ABSTRACT

Background: Pancreatic cancer is one of the most lethal of human malignancies known to date and shows relative insensitivity towards most of the clinically available therapy regimens. 3,5-bis(2-fluorobenzylidene)-4-piperidone (EF24), a novel synthetic curcumin analog, has shown promising in vitro therapeutic efficacy in various human cancer cells, but insufficient water solubility and systemic bioavailability limit its clinical application. Here, we describe nano-encapsulation of EF24 into pegylated liposomes (Lipo-EF24) and evaluation of these particles in preclinical in vitro and in vivo model systems of pancreatic cancer.

Results: Transmission electron microscopy and size distribution studies by dynamic light scattering confirmed intact spherical morphology of the formed liposomes with an average diameter of less than 150 nm. In vitro, treatment with Lipo-EF24 induced growth inhibition and apoptosis in MIAPaCa and Pa03C pancreatic cancer cells as assessed by using cell viability and proliferation assays, replating and soft agar clonogenicity assays as well as western blot analyses. Lipo-EF24 potently suppressed NF-kappaB nuclear translocation by inhibiting phosphorylation and subsequent degradation of its inhibitor I-kappa-B-alpha. In vivo, synergistic tumor growth inhibition was observed in MIAPaCa xenografts when Lipo-EF24 was given in combination with the standard-of-care cytotoxic agent gemcitabine. In line with in vitro observations, western blot analysis revealed decreased phosphorylation of I-kappa-B-alpha in excised Lipo-EF24-treated xenograft tumor tissues.

Conclusion: Due to its promising therapeutic efficacy and favorable toxicity profile Lipo-EF24 might be a promising starting point for development of future combinatorial therapeutic regimens against pancreatic cancer.

No MeSH data available.


Related in: MedlinePlus

Synthesis and characterization of void and EF24-containing PEGylated liposomes. Pegylated liposomes synthesized using a lipid hydration method were further characterized using DLS and TEM. a DLS of void and EF24-loaded liposomes revealed a narrow size distribution with an average diameter of less than 150 nm. b Transmission electron microscopy of void (left panel) and EF24-containing liposomes (right panel) demonstrated spherical morphology and an average diameter of around 120 nm, in line with the data obtained by DLS. c The stabilities of void and EF24-loaded liposomes were determined at three different temperatures (4, 20 and 37 °C) using DLS over a period of 40 days
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Fig2: Synthesis and characterization of void and EF24-containing PEGylated liposomes. Pegylated liposomes synthesized using a lipid hydration method were further characterized using DLS and TEM. a DLS of void and EF24-loaded liposomes revealed a narrow size distribution with an average diameter of less than 150 nm. b Transmission electron microscopy of void (left panel) and EF24-containing liposomes (right panel) demonstrated spherical morphology and an average diameter of around 120 nm, in line with the data obtained by DLS. c The stabilities of void and EF24-loaded liposomes were determined at three different temperatures (4, 20 and 37 °C) using DLS over a period of 40 days

Mentions: Hydration technique was used to generate liposomes in the presence of EF24, followed by an extrusion procedure to obtain a homogenous particle size. Due to its lipophilic structure, EF24 was predominantly encapsulated in the interior of liposomal bilayers. The average diameter and size distribution of void and EF24-loaded liposomes were routinely measured using dynamic light scattering (DLS) as illustrated in Fig. 2a. Both void liposomes as well as liposomes loaded with EF24 showed a narrow size distribution with an average diameter of less than 150 nm. Likewise, transmission electron microscopy (TEM) of the obtained liposomal particles demonstrated intact, round vesicles with an average diameter of <150 nm, and no difference in mean size was observed between void and EF24-loaded liposomes. Moreover, mixing of phospholipids and EF24 at different ratios revealed a maximum encapsulation of 5 mol% of EF24 in liposomes without affecting the structural integrity of liposomes (Fig. 2b). Loading of EF24 in liposomes was determined using gel permeation chromatography and unencapsulated EF24 in the eluted buffer was quantified by means of gas chromatography–mass spectrometry (GC–MS). No EF24 was detected in different eluates thereby confirming complete and stable incorporation of EF24 within liposomal phospholipid bilayers. Next, liposomal particles thus prepared were tested for their stability and shelf life at different storage temperatures (4, 20, and 37 °C, respectively) using DLS. Of note, liposomes displayed high stability and showed no agglomeration or change in their average diameter over 40 days (Fig. 2c), possibly due to PEGylation of the liposomal surface.Fig. 2


A liposomal formulation of the synthetic curcumin analog EF24 (Lipo-EF24) inhibits pancreatic cancer progression: towards future combination therapies.

Bisht S, Schlesinger M, Rupp A, Schubert R, Nolting J, Wenzel J, Holdenrieder S, Brossart P, Bendas G, Feldmann G - J Nanobiotechnology (2016)

Synthesis and characterization of void and EF24-containing PEGylated liposomes. Pegylated liposomes synthesized using a lipid hydration method were further characterized using DLS and TEM. a DLS of void and EF24-loaded liposomes revealed a narrow size distribution with an average diameter of less than 150 nm. b Transmission electron microscopy of void (left panel) and EF24-containing liposomes (right panel) demonstrated spherical morphology and an average diameter of around 120 nm, in line with the data obtained by DLS. c The stabilities of void and EF24-loaded liposomes were determined at three different temperatures (4, 20 and 37 °C) using DLS over a period of 40 days
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4940769&req=5

Fig2: Synthesis and characterization of void and EF24-containing PEGylated liposomes. Pegylated liposomes synthesized using a lipid hydration method were further characterized using DLS and TEM. a DLS of void and EF24-loaded liposomes revealed a narrow size distribution with an average diameter of less than 150 nm. b Transmission electron microscopy of void (left panel) and EF24-containing liposomes (right panel) demonstrated spherical morphology and an average diameter of around 120 nm, in line with the data obtained by DLS. c The stabilities of void and EF24-loaded liposomes were determined at three different temperatures (4, 20 and 37 °C) using DLS over a period of 40 days
Mentions: Hydration technique was used to generate liposomes in the presence of EF24, followed by an extrusion procedure to obtain a homogenous particle size. Due to its lipophilic structure, EF24 was predominantly encapsulated in the interior of liposomal bilayers. The average diameter and size distribution of void and EF24-loaded liposomes were routinely measured using dynamic light scattering (DLS) as illustrated in Fig. 2a. Both void liposomes as well as liposomes loaded with EF24 showed a narrow size distribution with an average diameter of less than 150 nm. Likewise, transmission electron microscopy (TEM) of the obtained liposomal particles demonstrated intact, round vesicles with an average diameter of <150 nm, and no difference in mean size was observed between void and EF24-loaded liposomes. Moreover, mixing of phospholipids and EF24 at different ratios revealed a maximum encapsulation of 5 mol% of EF24 in liposomes without affecting the structural integrity of liposomes (Fig. 2b). Loading of EF24 in liposomes was determined using gel permeation chromatography and unencapsulated EF24 in the eluted buffer was quantified by means of gas chromatography–mass spectrometry (GC–MS). No EF24 was detected in different eluates thereby confirming complete and stable incorporation of EF24 within liposomal phospholipid bilayers. Next, liposomal particles thus prepared were tested for their stability and shelf life at different storage temperatures (4, 20, and 37 °C, respectively) using DLS. Of note, liposomes displayed high stability and showed no agglomeration or change in their average diameter over 40 days (Fig. 2c), possibly due to PEGylation of the liposomal surface.Fig. 2

Bottom Line: Lipo-EF24 potently suppressed NF-kappaB nuclear translocation by inhibiting phosphorylation and subsequent degradation of its inhibitor I-kappa-B-alpha.In vivo, synergistic tumor growth inhibition was observed in MIAPaCa xenografts when Lipo-EF24 was given in combination with the standard-of-care cytotoxic agent gemcitabine.In line with in vitro observations, western blot analysis revealed decreased phosphorylation of I-kappa-B-alpha in excised Lipo-EF24-treated xenograft tumor tissues.

View Article: PubMed Central - PubMed

Affiliation: Department of Internal Medicine 3, Center of Integrated Oncology (CIO) Cologne-Bonn, University Hospital of Bonn, Sigmund-Freud-Str. 25, 53127, Bonn, Germany.

ABSTRACT

Background: Pancreatic cancer is one of the most lethal of human malignancies known to date and shows relative insensitivity towards most of the clinically available therapy regimens. 3,5-bis(2-fluorobenzylidene)-4-piperidone (EF24), a novel synthetic curcumin analog, has shown promising in vitro therapeutic efficacy in various human cancer cells, but insufficient water solubility and systemic bioavailability limit its clinical application. Here, we describe nano-encapsulation of EF24 into pegylated liposomes (Lipo-EF24) and evaluation of these particles in preclinical in vitro and in vivo model systems of pancreatic cancer.

Results: Transmission electron microscopy and size distribution studies by dynamic light scattering confirmed intact spherical morphology of the formed liposomes with an average diameter of less than 150 nm. In vitro, treatment with Lipo-EF24 induced growth inhibition and apoptosis in MIAPaCa and Pa03C pancreatic cancer cells as assessed by using cell viability and proliferation assays, replating and soft agar clonogenicity assays as well as western blot analyses. Lipo-EF24 potently suppressed NF-kappaB nuclear translocation by inhibiting phosphorylation and subsequent degradation of its inhibitor I-kappa-B-alpha. In vivo, synergistic tumor growth inhibition was observed in MIAPaCa xenografts when Lipo-EF24 was given in combination with the standard-of-care cytotoxic agent gemcitabine. In line with in vitro observations, western blot analysis revealed decreased phosphorylation of I-kappa-B-alpha in excised Lipo-EF24-treated xenograft tumor tissues.

Conclusion: Due to its promising therapeutic efficacy and favorable toxicity profile Lipo-EF24 might be a promising starting point for development of future combinatorial therapeutic regimens against pancreatic cancer.

No MeSH data available.


Related in: MedlinePlus