Targeting Cutaneous T-Cell Lymphoma Cells by Ingenol Mebutate (PEP005) Correlates with PKCδ Activation, ROS Induction as Well as Downregulation of XIAP and c-FLIP

New therapeutic strategies are needed for cutaneous T-cell lymphoma (CTCL), and the plant extract ingenol mebutate (PEP005) may be considered. PEP005 has been approved for actinic keratosis, and proapoptotic activities were described in different cancer cells. Here, we aimed to investigate its efficacy in four CTCL cell lines and its mode of action. While HuT-78 and HH responded with induced apoptosis as well as with loss of cell viability and cell proliferation, MyLa and SeAx remained resistant. Interestingly, both sensitive and resistant cells showed caspase-8 activation and enhanced levels of reactive oxygen species (ROS), while final caspase-3 activation was restricted to sensitive cells. Apoptosis induction was prevented by the caspase inhibitor QVD-Oph as well as by the antioxidant vitamin E. Caspase activation by PEP005 may be explained to some extent by the downregulation of the caspase antagonistic proteins c-FLIP and XIAP in sensitive cells, whereas both proteins were strongly expressed in resistant cells. Finally, PEP005 resulted in the activation of proapoptotic PKCδ, and the PKC inhibitor bisindolylmaleimide I reduced apoptosis, caspase-3 processing and ROS production, as well as restored cell viability. In conclusion, PKCδ appeared as a central player in apoptosis regulation in CTCL cells, also suggesting its therapeutic targeting.

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Analysis of the Effect of the Novel Histone Deacetylase Inhibitor, Depsipeptide (FK228/FR901228) on Mantle Cell Lymphoma.

Blood ◽

10.1182/blood.v104.11.2499.2499 ◽

2004 ◽

Vol 104 (11) ◽

pp. 2499-2499

Author(s):

Gladell P. Paner ◽

Serhan Alkan

Keyword(s):

T Cell ◽

Mantle Cell Lymphoma ◽

Cell Line ◽

Cell Lymphoma ◽

T Cell Lymphoma ◽

Cutaneous T Cell Lymphoma ◽

Mantle Cell ◽

Induced Apoptosis ◽

Hodgkin's Lymphomas ◽

H3 Acetylation

Abstract Background: Mantle cell lymphoma (MCL) comprises approximately 3–5% of the non-Hodgkin’s lymphomas and the vast majority of these patients are incurable. Histone deacetylases (HDAC) inhibitors are a new class of chemotherapeutic drugs that have been shown to inhibit cell proliferation and induce apoptosis in a variety of malignancies. Depsipeptide (FK228/FR901228) is a novel inhibitor of class I HDAC and was shown to be effective in patients with cutaneous T-cell lymphoma. Design: A MCL cell line, JeKo-1 was treated with varying concentrations of depsipeptide and analyzed for evidence of apoptosis. Apoptosis was analyzed by flow cytometry (Annexin and 7AAD staining) and by microscopic examination. The effect on the status of H3 histone acetylation and changes in the expression of the Bcl-2 family proteins (Bcl-2, Bcl-xl and Mcl-1) following treatment with depsipeptide were investigated by flow cytometric evaluation. Requirement for de novo protein synthesis and activation of JNK in depsipeptide-induced apoptosis was analyzed by treatment with cycloheximide (CHX) and JNK inhibitor (SP600125) prior to addition of depsipeptide respectively. The effect of depsipeptide in 5 primary MCL patient samples was then analyzed for morphologic evidence of apoptosis. Results: Depsipeptide (0.25 mM/L; 80%apoptosis) induced marked apoptosis in JeKo-1 cells and this was shown to be a dose dependent fashion following 12 hours incubation. There was increase in H3 acetylation, after treatment with depsipeptide. Bcl-2, Bcl-xl and Mcl-1 showed decreased expression in the depsipeptide treated samples. Treatment with CHX (100ng/ml and 500ng/ml) and SP600125 (20ml/L) had no effect to the ability of depsipeptide-induced apoptosis. Primary MCL cells of 5 patients also showed marked apoptosis with depsipeptide treatment. Conclusion: Depsipeptide causes increased H3 acetylation and induces apoptosis in MCL cell line and primary MCL cells. The mitochondrial apoptotic pathway is possibly altered by the depsipeptide treatment causing apoptosis, by down-regulation of Bcl-2, Bcl-xl and Mcl-1 proteins. Based on the recent phase I clinical trial demonstrating clinical response in cutaneous T cell lymphoma, our study supports the potential clinical utilization of depsipeptide in patients with MCL.

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miR-122 Regulates p53/Akt Signalling and the Chemotherapy-Induced Apoptosis in Cutaneous T-Cell Lymphoma

PLoS ONE ◽

10.1371/journal.pone.0029541 ◽

2012 ◽

Vol 7 (1) ◽

pp. e29541 ◽

Cited By ~ 67

Author(s):

Valentina Manfè ◽

Edyta Biskup ◽

Anne Rosbjerg ◽

Maria Kamstrup ◽

Anne Guldhammer Skov ◽

...

Keyword(s):

T Cell ◽

Cell Lymphoma ◽

T Cell Lymphoma ◽

Cutaneous T Cell Lymphoma ◽

Induced Apoptosis

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Notch1 as a potential therapeutic target in cutaneous T-cell lymphoma

Blood ◽

10.1182/blood-2009-12-260216 ◽

2010 ◽

Vol 116 (14) ◽

pp. 2504-2512 ◽

Cited By ~ 61

Author(s):

Maria R. Kamstrup ◽

Lise Mette Rahbek Gjerdrum ◽

Edyta Biskup ◽

Britt Thyssing Lauenborg ◽

Elisabeth Ralfkiaer ◽

...

Keyword(s):

T Cell ◽

Notch Signaling ◽

Mycosis Fungoides ◽

Cell Lymphoma ◽

Skin Lesions ◽

T Cell Lymphoma ◽

Sézary Syndrome ◽

Sezary Syndrome ◽

Cutaneous T Cell Lymphoma ◽

Induced Apoptosis

AbstractDeregulation of Notch signaling has been linked to the development of T-cell leukemias and several solid malignancies. Yet, it is unknown whether Notch signaling is involved in the pathogenesis of mycosis fungoides and Sézary syndrome, the most common subtypes of cutaneous T-cell lymphoma. By immunohistochemistry of 40 biopsies taken from skin lesions of mycosis fungoides and Sézary syndrome, we demonstrated prominent expression of Notch1 on tumor cells, especially in the more advanced stages. The γ-secretase inhibitor I blocked Notch signaling and potently induced apoptosis in cell lines derived from mycosis fungoides (MyLa) and Sézary syndrome (SeAx, HuT-78) and in primary leukemic Sézary cells. Specific down-regulation of Notch1 (but not Notch2 and Notch3) by siRNA induced apoptosis in SeAx. The mechanism of apoptosis involved the inhibition of nuclear factor-κB, which is the most important prosurvival pathway in cutaneous T-cell lymphoma. Our data show that Notch is present in cutaneous T-cell lymphoma and that its inhibition may provide a new way to treat cutaneous T-cell lymphoma.

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Cotreatment with BCL-2 antagonist sensitizes cutaneous T-cell lymphoma to lethal action of HDAC7-Nur77–based mechanism

Blood ◽

10.1182/blood-2008-08-176024 ◽

2009 ◽

Vol 113 (17) ◽

pp. 4038-4048 ◽

Cited By ~ 34

Author(s):

Jianguang Chen ◽

Warren Fiskus ◽

Kelly Eaton ◽

Pravina Fernandez ◽

Yongchao Wang ◽

...

Keyword(s):

T Cell ◽

Histone Deacetylase ◽

Histone Deacetylase Inhibitors ◽

Cell Lymphoma ◽

Ectopic Expression ◽

T Cell Lymphoma ◽

Orphan Receptor ◽

Cutaneous T Cell Lymphoma ◽

Induced Apoptosis

Abstract Pan-histone deacetylase inhibitors, for example, vorinostat and panobinostat (LBH589; Novartis Pharmaceuticals, East Hanover, NJ), have shown clinical efficacy against advanced cutaneous T-cell lymphoma (CTCL). However, the molecular basis of this activity remains unclear. HDAC7, a class IIA histone deacetylase (HDAC), is overexpressed in thymocytes, where it represses expression of the proapoptotic nuclear orphan receptor Nur77. Here, we demonstrate that treatment with panobinostat rapidly inhibits the in vitro and intracellular activity, as well as the mRNA and protein levels of HDAC7, and induces expression and translocation of Nur77 to the mitochondria. There, Nur77 converts death resistance protein Bcl-2 into a killer protein, promoting cell death of cultured and patient-derived human CTCL cells. Treatment with panobinostat improved survival of athymic nude mice implanted with human CTCL cells. Ectopic expression of Nur77 induced apoptosis and sensitized HH cells to panobinostat, whereas combined knockdown of Nur77 and its family member Nor1 was necessary to inhibit panobinostat-induced apoptosis of CTCL cells. Cotreatment with the Bcl-2/Bcl-xL antagonist ABT-737 decreased resistance and synergistically induced apoptosis of human CTCL cells. These findings mechanistically implicate HDAC7 and Nur77 in sensitizing human CTCL cells to panobinostat as well as suggest that cotreatment with an anti–Bcl-2 agent would augment the anti-CTCL activity of panobinostat.

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