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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

In vivo therapeutic effect of Lipo-EF24 on MIAPaCa xenograft tumor growth. a Growth of subcutaneous MIAPaCa xenografts was significantly inhibited in nude mice after treatment with Lipo-EF24 and gemcitabine in combination as shown by measured tumor volumes (n = 8) for each treatment arm after 3 weeks. Lipo-EF24 or gemcitabine used as single agents did not show any significant effect when compared to void liposomes as control. b Tumor weights measured at the end of treatment also showed significant reduction in the combination treatment arm as compared to either single agents or void liposomal control. c During the course of treatment, no difference in the mean body weight of mice was observed between the respective treatment arms. d Lipo-EF24 in combination with gemcitabine suppressed NF-kappaB activation in MIAPaCa xenografts, as demonstrated by marked inhibition of the phosphorylated form of its inhibitor protein I-kappa-B-alpha as well as NF-kappaB-p65, determined by western blot analysis of frozen tumor tissues
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Fig8: In vivo therapeutic effect of Lipo-EF24 on MIAPaCa xenograft tumor growth. a Growth of subcutaneous MIAPaCa xenografts was significantly inhibited in nude mice after treatment with Lipo-EF24 and gemcitabine in combination as shown by measured tumor volumes (n = 8) for each treatment arm after 3 weeks. Lipo-EF24 or gemcitabine used as single agents did not show any significant effect when compared to void liposomes as control. b Tumor weights measured at the end of treatment also showed significant reduction in the combination treatment arm as compared to either single agents or void liposomal control. c During the course of treatment, no difference in the mean body weight of mice was observed between the respective treatment arms. d Lipo-EF24 in combination with gemcitabine suppressed NF-kappaB activation in MIAPaCa xenografts, as demonstrated by marked inhibition of the phosphorylated form of its inhibitor protein I-kappa-B-alpha as well as NF-kappaB-p65, determined by western blot analysis of frozen tumor tissues

Mentions: In vivo therapeutic efficacy of Lipo-EF24—administered as monotherapy as well as in combination with the standard-of-care cytostatic drug gemcitabine—was assessed using MIAPaCa pancreatic cancer xenografts. In line with previous reports gemcitabine caused significant growth retardation of MIAPaCa xenografts. As opposed to this, monotherapy with Lipo-EF24 lead to only marginal initial growth delay during the first 2 weeks of therapy (data not shown), but this effect did not persist during the following course of therapy, possibly due to in vivo selection of resistant subclones of neoplastic cells under monotherapy. This observation prompted investigation of a combinatorial regimen of Lipo-EF24 plus gemcitabine. Of note, significantly enhanced tumor growth inhibition was observed in mice that received a combination regimen of Lipo-EF24 plus gemcitabine as compared to single agent gemcitabine or Lipo-EF24 therapy, respectively (Fig. 8a). Likewise, significant decrease in the average final tumor weights was observed in the combination therapy as compared to the other three treatment arms (Fig. 8b). Thorough necropsy and histological examination of major organs was performed after the end of treatment and again did not reveal any apparent signs of toxicity or differences in mean body weights between the respective treatment arms (Fig. 8c). Xenograft tumor tissues were harvested at the end of treatment for analysis of drug target genes. Western blot analyses of excised tumors were found to be in line with previous in vitro results and showed decreased phosphorylation of I-kappa-B-alpha in both EF24 treatment arms (i.e. monotherapy or gemcitabine combination, respectively), while void liposomes or gemcitabine both did not show any such effect (Fig. 8d). Used as monotherapeutic agent, Lipo-EF24 failed to suppress NF-kappaB activation in vivo as observed in western blot analyses of resected xenograft tumor tissues. However, in combination with gemcitabine significant inhibition of phosphorylation of NF-kappaB-p65 and hence inactivation of NF-kappaB signaling could be detected even in the in vivo situation in resected tumor tissues.Fig. 8


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)

In vivo therapeutic effect of Lipo-EF24 on MIAPaCa xenograft tumor growth. a Growth of subcutaneous MIAPaCa xenografts was significantly inhibited in nude mice after treatment with Lipo-EF24 and gemcitabine in combination as shown by measured tumor volumes (n = 8) for each treatment arm after 3 weeks. Lipo-EF24 or gemcitabine used as single agents did not show any significant effect when compared to void liposomes as control. b Tumor weights measured at the end of treatment also showed significant reduction in the combination treatment arm as compared to either single agents or void liposomal control. c During the course of treatment, no difference in the mean body weight of mice was observed between the respective treatment arms. d Lipo-EF24 in combination with gemcitabine suppressed NF-kappaB activation in MIAPaCa xenografts, as demonstrated by marked inhibition of the phosphorylated form of its inhibitor protein I-kappa-B-alpha as well as NF-kappaB-p65, determined by western blot analysis of frozen tumor tissues
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Related In: Results  -  Collection

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Fig8: In vivo therapeutic effect of Lipo-EF24 on MIAPaCa xenograft tumor growth. a Growth of subcutaneous MIAPaCa xenografts was significantly inhibited in nude mice after treatment with Lipo-EF24 and gemcitabine in combination as shown by measured tumor volumes (n = 8) for each treatment arm after 3 weeks. Lipo-EF24 or gemcitabine used as single agents did not show any significant effect when compared to void liposomes as control. b Tumor weights measured at the end of treatment also showed significant reduction in the combination treatment arm as compared to either single agents or void liposomal control. c During the course of treatment, no difference in the mean body weight of mice was observed between the respective treatment arms. d Lipo-EF24 in combination with gemcitabine suppressed NF-kappaB activation in MIAPaCa xenografts, as demonstrated by marked inhibition of the phosphorylated form of its inhibitor protein I-kappa-B-alpha as well as NF-kappaB-p65, determined by western blot analysis of frozen tumor tissues
Mentions: In vivo therapeutic efficacy of Lipo-EF24—administered as monotherapy as well as in combination with the standard-of-care cytostatic drug gemcitabine—was assessed using MIAPaCa pancreatic cancer xenografts. In line with previous reports gemcitabine caused significant growth retardation of MIAPaCa xenografts. As opposed to this, monotherapy with Lipo-EF24 lead to only marginal initial growth delay during the first 2 weeks of therapy (data not shown), but this effect did not persist during the following course of therapy, possibly due to in vivo selection of resistant subclones of neoplastic cells under monotherapy. This observation prompted investigation of a combinatorial regimen of Lipo-EF24 plus gemcitabine. Of note, significantly enhanced tumor growth inhibition was observed in mice that received a combination regimen of Lipo-EF24 plus gemcitabine as compared to single agent gemcitabine or Lipo-EF24 therapy, respectively (Fig. 8a). Likewise, significant decrease in the average final tumor weights was observed in the combination therapy as compared to the other three treatment arms (Fig. 8b). Thorough necropsy and histological examination of major organs was performed after the end of treatment and again did not reveal any apparent signs of toxicity or differences in mean body weights between the respective treatment arms (Fig. 8c). Xenograft tumor tissues were harvested at the end of treatment for analysis of drug target genes. Western blot analyses of excised tumors were found to be in line with previous in vitro results and showed decreased phosphorylation of I-kappa-B-alpha in both EF24 treatment arms (i.e. monotherapy or gemcitabine combination, respectively), while void liposomes or gemcitabine both did not show any such effect (Fig. 8d). Used as monotherapeutic agent, Lipo-EF24 failed to suppress NF-kappaB activation in vivo as observed in western blot analyses of resected xenograft tumor tissues. However, in combination with gemcitabine significant inhibition of phosphorylation of NF-kappaB-p65 and hence inactivation of NF-kappaB signaling could be detected even in the in vivo situation in resected tumor tissues.Fig. 8

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