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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

Lipo-EF24 blocks I-kappa-B-alpha (IkBa) phosphorylation and NF-kappaB activation. The effect of void liposomes (VL) or Lipo-EF24 (EL) on NF-kappaB pathway activity in a MIAPaCa or b Pa03C cells was assessed by quantifying the protein expression levels of phospho-I-kappa-B-alpha (p-IκBα), I-kappa-B-alpha (IκBα), phospho-NF-kappaB-p65 (p-NFκB p65) and NF-kappaBp-65 (NFκB p65) in cytoplasmic (CE) as well as nuclear (NE) extracts, GAPDH was used as loading control
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Fig5: Lipo-EF24 blocks I-kappa-B-alpha (IkBa) phosphorylation and NF-kappaB activation. The effect of void liposomes (VL) or Lipo-EF24 (EL) on NF-kappaB pathway activity in a MIAPaCa or b Pa03C cells was assessed by quantifying the protein expression levels of phospho-I-kappa-B-alpha (p-IκBα), I-kappa-B-alpha (IκBα), phospho-NF-kappaB-p65 (p-NFκB p65) and NF-kappaBp-65 (NFκB p65) in cytoplasmic (CE) as well as nuclear (NE) extracts, GAPDH was used as loading control

Mentions: The oncogenic NF-kappaB pathway is constitutively active in human pancreatic cancer [27], moreover curcumin has previously been identified as potent inhibitor of NF-kappaB signaling [28]. A recent study suggests that the curcumin derivative EF24 suppresses NF-kappaB activation by directly inhibiting the degradation of I-kappa-B-alpha [24], the inhibitory cytosolic subunit of NF-kappaB, whose phosphorylation and subsequent degradation is a prerequisite for activation of the NF-kappaB pathway. Hence, in order to measure the effects of Lipo-EF24 on NF-kappaB signaling, cytoplasmic and nuclear proteins were extracted from treated MIAPaCa and Pa03C cells, respectively, and subjected to western blot analysis. As shown in Fig. 5, liposomal EF24 effectively inhibited phosphorylation of I-kappa-B-alpha as well as NF-kappaB-p65 and subsequent nuclear translocation of NF-kappaB-p65 in a dose-dependent manner. Moreover, a marked increase in the expression levels of total I-kappa-B-alpha was also observed in MIAPaCa cells treated with Lipo-EF24 at a concentration of 10 µM, indicating that EF24 protects I-kappa-B-alpha from subsequent cytosolic degradation.Fig. 5


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)

Lipo-EF24 blocks I-kappa-B-alpha (IkBa) phosphorylation and NF-kappaB activation. The effect of void liposomes (VL) or Lipo-EF24 (EL) on NF-kappaB pathway activity in a MIAPaCa or b Pa03C cells was assessed by quantifying the protein expression levels of phospho-I-kappa-B-alpha (p-IκBα), I-kappa-B-alpha (IκBα), phospho-NF-kappaB-p65 (p-NFκB p65) and NF-kappaBp-65 (NFκB p65) in cytoplasmic (CE) as well as nuclear (NE) extracts, GAPDH was used as loading control
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

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

Fig5: Lipo-EF24 blocks I-kappa-B-alpha (IkBa) phosphorylation and NF-kappaB activation. The effect of void liposomes (VL) or Lipo-EF24 (EL) on NF-kappaB pathway activity in a MIAPaCa or b Pa03C cells was assessed by quantifying the protein expression levels of phospho-I-kappa-B-alpha (p-IκBα), I-kappa-B-alpha (IκBα), phospho-NF-kappaB-p65 (p-NFκB p65) and NF-kappaBp-65 (NFκB p65) in cytoplasmic (CE) as well as nuclear (NE) extracts, GAPDH was used as loading control
Mentions: The oncogenic NF-kappaB pathway is constitutively active in human pancreatic cancer [27], moreover curcumin has previously been identified as potent inhibitor of NF-kappaB signaling [28]. A recent study suggests that the curcumin derivative EF24 suppresses NF-kappaB activation by directly inhibiting the degradation of I-kappa-B-alpha [24], the inhibitory cytosolic subunit of NF-kappaB, whose phosphorylation and subsequent degradation is a prerequisite for activation of the NF-kappaB pathway. Hence, in order to measure the effects of Lipo-EF24 on NF-kappaB signaling, cytoplasmic and nuclear proteins were extracted from treated MIAPaCa and Pa03C cells, respectively, and subjected to western blot analysis. As shown in Fig. 5, liposomal EF24 effectively inhibited phosphorylation of I-kappa-B-alpha as well as NF-kappaB-p65 and subsequent nuclear translocation of NF-kappaB-p65 in a dose-dependent manner. Moreover, a marked increase in the expression levels of total I-kappa-B-alpha was also observed in MIAPaCa cells treated with Lipo-EF24 at a concentration of 10 µM, indicating that EF24 protects I-kappa-B-alpha from subsequent cytosolic degradation.Fig. 5

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