Resistance of cutaneous anaplastic large-cell lymphoma cells to apoptosis by death ligands is enhanced by CD30-mediated overexpression of c-FLIP

Pathology and genetics of anaplastic large cell lymphoma

Anaplastic large cell lymphomas are a rare subtype of peripheral/mature T-cell lymphomas which are clinically, pathologically and genetically heterogeneous. Both ALK-positive (ALK+) and ALK-negative (ALK-) ALCL are composed of large lymphoid cells with abundant cytoplasm and pleomorphic features with horseshoe-shaped and reniform nuclei. ALK+ ALCL were considered as a definite entity in the 2008 World Health Organization classification of hematopoietic and lymphoid tissues. ALK-ALCL was included as a provisional entity in the WHO 2008 edition and in the most recent 2017 edition, it is now considered a distinct entity that includes cytogenetic subsets that appear to have prognostic implications (e.g. 6p25 rearrangements at IRF4/DUSP22 locus). ALK+ ALCLs are distinct in epidemiology and pathogenetic origin and should be distinguished from ALK-ALCL, cutaneous ALCL and breast implant associated ALCL which have distinct clinical course and pathogenetic features. Breast implant-associated ALCL is now recognized as a new provisional entity distinct from other ALK-ALCL; notably that it is a noninvasive disease associated with excellent outcome. In this article, we will provide an overview of the salient themes relevant to the pathology and genetic mechanisms in ALCL.

Countering TRAIL Resistance in Melanoma

Melanoma of the skin has become a prime example for demonstrating the success of targeted cancer therapy. Nevertheless, high mortality has remained, mainly related to tumor heterogeneity and inducible therapy resistance. But the development of new therapeutic strategies and combinations has raised hope of finally defeating this deadly disease. TNF-related apoptosis-inducing ligand (TRAIL) represents a promising antitumor strategy. The principal sensitivity of melanoma cells for TRAIL was demonstrated in previous studies; however, inducible resistance appeared as a major problem. To address this issue, combination strategies were tested, and survival pathway inhibitors were shown to sensitize melanoma cells for TRAIL-induced apoptosis. Finally, cell cycle inhibition was identified as a common principle of TRAIL sensitization in melanoma cells. Mitochondrial apoptosis pathways, pro- and antiapoptotic Bcl-2 proteins as well as the rheostat consisted of Smac (Second mitochondria-derived activator of caspase) and XIAP (X-linked inhibitor of apoptosis protein) appeared to be of particular importance. Furthermore, the role of reactive oxygen species (ROS) was recognized in this setting. Inducible TRAIL resistance in melanoma can be explained by (i) high levels of antiapoptotic Bcl-2 proteins, (ii) high levels of XIAP, and (iii) suppressed Bax activity. These hurdles have to be overcome to enable the use of TRAIL in melanoma therapy. Several strategies appear as particularly promising, including new TRAIL receptor agonists, Smac and BH3 mimetics, as well as selective kinase inhibitors.

Key Role of Reactive Oxygen Species (ROS) in Indirubin Derivative-Induced Cell Death in Cutaneous T-Cell Lymphoma Cells

Cutaneous T-cell lymphoma (CTCL) may develop a highly malignant phenotype in its late phase, and patients may profit from innovative therapies. The plant extract indirubin and its chemical derivatives represent new and promising antitumor strategies. This first report on the effects of an indirubin derivative in CTCL cells shows a strong decrease of cell proliferation and cell viability as well as an induction of apoptosis, suggesting indirubin derivatives for therapy of CTCL. As concerning the mode of activity, the indirubin derivative DKP-071 activated the extrinsic apoptosis cascade via caspase-8 and caspase-3 through downregulation of the caspase antagonistic proteins c-FLIP and XIAP. Importantly, a strong increase of reactive oxygen species (ROS) was observed as an immediate early effect in response to DKP-071 treatment. The use of antioxidative pre-treatment proved the decisive role of ROS, which turned out upstream of all other proapoptotic effects monitored. Thus, reactive oxygen species appear as a highly active proapoptotic pathway in CTCL, which may be promising for therapeutic intervention. This pathway can be efficiently activated by an indirubin derivative.

CD30-Positive Lymphoproliferative Disorders

Primary cutaneous CD30-positive lymphoproliferative disorders (CD30+ LPD) encompass lymphomatoid papulosis (LyP), primary cutaneous anaplastic large cell lymphoma (pcALCL), and borderline lesions [1]. CD30+ LPD are the second most common cutaneous T-cell lymphomas (CTCL) after mycosis fungoides (MF) and represent approximately 25% of all CTCL cases [2]. Their common phenotypic hallmark is an expression of the CD30 antigen, a cytokine receptor belonging to the tumor necrosis factor (TNF) receptor superfamily. Both LyP and pcALCL show numerous clinical, histological and immunophenotypic variants, and generally have an indolent course with a favorable prognosis. Overlapping features of LyP and pcALCL with other CD30+ T-cell lymphomas, inflammatory, and/or infectious conditions emphasize the importance of careful clinicopathologic correlation and staging.

Aurora Kinase A Is Upregulated in Cutaneous T-Cell Lymphoma and Represents a Potential Therapeutic Target

Cutaneous T-cell lymphomas (CTCLs) form a heterogeneous group of non-Hodgkin's lymphomas characterized by only poor prognosis in advanced stage. Despite significant progress made in the identification of novel genes and pathways involved in the pathogenesis of cutaneous lymphoma, the therapeutic value of these findings has still to be proven. Here, we demonstrate by gene expression arrays that Aurora kinase A is one of the highly overexpressed genes of the serine/threonine kinase in CTCL. The finding was confirmed by quantitative reverse transcriptase-PCR, western blotting, and immunohistochemistry in CTCL cell lines and primary patient samples. Moreover, treatment with a specific Aurora kinase A inhibitor blocks cell proliferation by inducing cell cycle arrest in G2 phase, as well as apoptosis in CTCL cell lines. These data provide a promising rationale for using Aurora kinase A inhibition as a therapeutic modality of CTCL.

Hyperthermia restores apoptosis induced by death receptors through aggregation-induced c-FLIP cytosolic depletion

TRAIL is involved in immune tumor surveillance and is considered a promising anti-cancer agent owing to its limited side effects on healthy cells. However, some cancer cells display resistance, or become resistant to TRAIL-induced cell death. Hyperthermia can enhance sensitivity to TRAIL-induced cell death in various resistant cancer cell lines, including lung, breast, colon or prostate carcinomas. Mild heat shock treatment has been proposed to restore Fas ligand or TRAIL-induced apoptosis through c-FLIP degradation or the mitochondrial pathway. We demonstrate here that neither the mitochondria nor c-FLIP degradation are required for TRAIL-induced cell death restoration during hyperthermia. Our data provide evidence that insolubilization of c-FLIP, alone, is sufficient to enhance apoptosis induced by death receptors. Hyperthermia induced c-FLIP depletion from the cytosolic fraction, without apparent degradation, thereby preventing c-FLIP recruitment to the TRAIL DISC and allowing efficient caspase-8 cleavage and apoptosis. Hyperthermia-induced c-FLIP depletion was independent of c-FLIP DED2 FL chain assembly motif or ubiquitination-mediated c-FLIP degradation, as assessed using c-FLIP point mutants on lysine 167 and 195 or threonine 166, a phosphorylation site known to regulate ubiquitination of c-FLIP. Rather, c-FLIP depletion was associated with aggregation, because addition of glycerol not only prevented the loss of c-FLIP from the cytosol but also enabled c-FLIP recruitment within the TRAIL DISC, thus inhibiting TRAIL-induced apoptosis during hyperthermia. Altogether our results demonstrate that c-FLIP is a thermosensitive protein whose targeting by hyperthermia allows restoration of apoptosis induced by TNF ligands, including TRAIL. Our findings suggest that combining TRAIL agonists with whole-body or localized hyperthermia may be an interesting approach in cancer therapy.

Anaplastic large cell lymphomas: ALK positive, ALK negative, and primary cutaneous

Anaplastic large cell lymphomas (ALCLs) comprise a group of CD30-positive non-Hodgkin lymphomas that generally are of T-cell origin and share common morphologic and phenotypic characteristics. The World Health Organization recognizes 3 entities: primary cutaneous ALCL (pcALCL), anaplastic lymphoma kinase (ALK)-positive ALCL, and, provisionally, ALK-negative ALCL. Despite overlapping pathologic features, these tumors differ in clinical behavior and genetics. pcALCL presents in the skin and, while it may involve locoregional lymph nodes, rarely disseminates. Outcomes typically are excellent. ALK-positive ALCL and ALK-negative ALCL are systemic diseases. ALK-positive ALCLs consistently have chromosomal rearrangements involving the ALK gene with varied gene partners, and generally have a favorable prognosis. ALK-negative ALCLs lack ALK rearrangements and their genetic and clinical features are more variable. A subset of ALK-negative ALCLs has rearrangements in or near the DUSP22 gene and has a favorable prognosis similar to that of ALK-positive ALCL. DUSP22 rearrangements also are seen in a subset of pcALCLs. In this review, we discuss the clinical, morphologic, phenotypic, genetic, and biological features of ALCLs.

Increased Expression of Phosphorylated FADD in Anaplastic Large Cell and Other T-Cell Lymphomas

FAS-associated protein with death domain (FADD) is a major adaptor protein involved in extrinsic apoptosis, embryogenesis, and lymphocyte homeostasis. Although abnormalities of the FADD/death receptor apoptotic pathways have been established in tumorigenesis, fewer studies have analyzed the expression and role of phosphorylated FADD (pFADD). Our identification of FADD as a lymphoma-associated autoantigen in T-cell lymphoma patients raises the possibility that pFADD, with its correlation with cell cycle, may possess role(s) in human T-cell lymphoma development. This immunohistochemical study investigated pFADD protein expression in a range of normal tissues and lymphomas, particularly T-cell lymphomas that require improved therapies. Whereas pFADD was expressed only in scattered normal T cells, it was detected at high levels in T-cell lymphomas (eg, 84% anaplastic large cell lymphoma and 65% peripheral T cell lymphomas, not otherwise specified). The increased expression of pFADD supports further study of its clinical relevance and role in lymphomagenesis, highlighting phosphorylation of FADD as a potential therapeutic target.

Sensitization of melanoma cells for TRAIL-induced apoptosis by activation of mitochondrial pathways via Bax

The death ligand TRAIL (TNF-related apoptosis-inducing ligand) represents a promising therapeutic strategy for metastatic melanoma, however prevalent and inducible resistance limits its applicability and therapeutic use. Recent work has revealed that combinations with survival pathway inhibitors could efficiently sensitize melanoma cells for TRAIL. Here, a particular role was attributed to the activation of Bax, which is regulated by phosphorylation. Thus, TRAIL resistance in melanoma is explained by three major steps, namely high levels of antiapoptotic Bcl-2 proteins, high levels of inhibitor of apoptosis proteins (cIAPs) and suppressed Bax activity. Importantly, Bid was activated in response to TRAIL alone also in resistant cells to antagonize Bcl-2, and Bax was activated in response to pathway inhibitors. However, only in combinations, mitochondrial apoptosis pathways were opened to result in release of Smac/DIABLO, which functions as antagonist of cIAPs. Opening the caspase cascade by Smac then allowed efficient induction of apoptosis. Thus, direct or indirect targeting of Bax represents a suitable strategy to overcome TRAIL resistance in melanoma and may allow the establishment of TRAIL-based therapeutic approaches.

The role of charged multivesicular body protein 5 in programmed cell death in leukemic cells

The Homo sapiens charged multivesicular body protein 5 (CHMP5) is a member of the multivesicular body, which serves as an anti-apoptotic protein and is thought to participate in leukemogenesis. In this study, a short-hairpin RNA-based RNA interference approach was used to inhibit the expression of CHMP5 in the leukemic cell line U937. After CHMP5 was inhibited, antibody microarray and western blot analysis were used to study the changes in the programmed cell death (PCD) pathway. PCD can be classified into three types: apoptosis, necrosis, and autophagy. Results showed that caspase 3 was activated in CHMP5-deficient U937 cells, indicating that the apoptotic pathway was activated, although neither the intrinsic nor the extrinsic apoptotic pathways were activated. Our results also showed that the Granzyme B/Perforin apoptotic pathway was activated by CHMP5 silencing. Necrosis is activated by caspase-independent executioners. In this study, we showed that the apoptosis-inducing protein-mediated necrotic PCD pathway is activated after CHMP5 inhibition. It was found that autophagic PCD did not occur in CHMP5-deficient U937 cells. In conclusion, after CHMP5 inhibition, both Granzyme B/Perforin apoptotic pathway and apoptosis-inducing factor-mediated necrotic pathway were activated, while autophagic pathway was not activated.

Apoptosis induction by SAHA in cutaneous T-cell lymphoma cells is related to downregulation of c-FLIP and enhanced TRAIL signaling

Suberoylanilide hydroxamic acid (SAHA) has been approved for the treatment of cutaneous T-cell lymphoma (CTCL), but its mode of action remained largely elusive. As shown here in four CTCL cell lines, loss of cell viability correlated with significant time- and dose-dependent induction of apoptosis, whereas cytotoxicity was less pronounced. Both extrinsic and intrinsic apoptosis pathways were activated, as seen by processing of initiator caspases 8 and 9, loss of mitochondrial membrane potential, and cytochrome c release. Characteristically, antiapoptotic mediators such as Mcl-1, XIAP, survivin, and c-FLIP were downregulated. Consistent with its critical function, c-FLIP overexpression resulted in a significant decrease of SAHA-mediated apoptosis. Enhanced sensitivity to TRAIL (TNF-related apoptosis-inducing ligand) and enhanced TRAIL signaling was seen in CTCL cell lines with high sensitivity, whereas cell lines with moderate response were characterized by downregulation of TRAIL-R2 and weaker TRAIL expression. Comparable proapoptotic responses to SAHA and to the combination with TRAIL were seen in ex vivo tumor T cells of CTCL patients. Thus, activation of extrinsic apoptosis pathways, related to c-FLIP downregulation and enhanced TRAIL signaling, appeared as characteristic for CTCL cell responsiveness to SAHA. An improved understanding of the pathways may facilitate its targeted use and the selection of suitable combinations.

TRAIL-activated EGFR by Cbl-b-regulated EGFR redistribution in lipid rafts antagonises TRAIL-induced apoptosis in gastric cancer cells

Most gastric cancer cells are resistant to tumour necrosis factor-related apoptosis-inducing ligand (TRAIL). Since TRAIL resistance is associated with lipid rafts, in which both death receptors and epidermal growth factor receptors (EGFR) are enriched, our aim is to identify how lipid raft-regulated receptor redistribution influences the sensitivity of TRAIL in gastric cancer cells. In TRAIL-resistant gastric cancer cells, TRAIL did not induce effective death-inducing signalling complex (DISC) formation in lipid rafts, accompanied with EGFR translocation into lipid rafts, and activation of EGFR pathway. Knockdown of casitas B-lineage lymphoma-b (Cbl-b) enhanced TRAIL-induced apoptosis by promoting DISC formation in lipid rafts. However, knockdown of Cbl-b also enhanced EGFR translocation into lipid rafts and EGFR pathway activation induced by TRAIL. Either using inhibitors of EGFR or depletion of EGFR with small interfering RNA (siRNA) prevented EGFR pathway activation, and thus increased TRAIL-induced apoptosis, especially in Cbl-b knockdown clones. Taken together, TRAIL-induced EGFR activation through Cbl-b-regulated EGFR redistribution in lipid rafts antagonised TRAIL-induced apoptosis. The contribution of DISC formation and the inhibition of EGFR signal triggered in lipid rafts are both essential for increasing the sensitivity of gastric cancer cells to TRAIL.

High soluble CD30, CD25, and IL-6 may identify patients with worse survival in CD30+ cutaneous lymphomas and early mycosis fungoides

Histopathology alone cannot predict outcome of patients with CD30+ primary cutaneous lymphoproliferative disorders (CD30CLPD) and early mycosis fungoides (MF). To test the hypothesis that serum cytokines/cytokine receptors provide prognostic information in these disorders, we measured soluble CD30 (sCD30), sCD25, and selected cytokines in cell cultures and sera of 116 patients with CD30CLPD and 96 patients with early MF followed up to 20 years. Significant positive correlation was found between sCD30 levels and sCD25, CD40L, IL-6, and IL-8, suggesting CD30+ neoplastic cells secrete these cytokines, but not Th2 cytokines. In vitro studies confirmed sCD30, sCD25, IL-6 and IL-8 are secreted by CD30CLPD-derived cell lines. CD30CLPD patients with above normal sCD30 and sCD25 had worse overall and disease-related survivals, but only sCD30 retained significance in Cox models that included advanced age. High sCD30 also identified patients with worse survival in early MF. Increased IL-6 and IL-8 correlated with poor disease-related survival in CD30CLPD patients, We conclude that: (1) neoplastic cells of some CD30CLPD patients do not resemble Th2 cells, (2) high serum sCD30, sCD25, IL-6, and perhaps IL-8 levels may provide prognostic information useful for patient management.

High soluble CD30, CD25, and IL-6 may identify patients with worse survival in CD30+ cutaneous lymphomas and early mycosis fungoides

Histopathology alone cannot predict the outcome of patients with CD30+ primary cutaneous lymphoproliferative disorders (CD30CLPD) and early mycosis fungoides (MF). To test the hypothesis that serum cytokines/cytokine receptors provide prognostic information in these disorders, we measured soluble CD30 (sCD30), sCD25, and selected cytokines in cell cultures and sera of 116 patients with CD30CLPD and 96 patients with early MF followed up to 20 years. Significant positive correlation was found between sCD30 levels and sCD25, CD40L, IL-6, and IL-8, suggesting that CD30+ neoplastic cells secrete these cytokines, but not Th2 cytokines. In vitro studies confirmed that sCD30, sCD25, IL-6, and IL-8 are secreted by CD30CLPD-derived cell lines. CD30CLPD patients with above normal sCD30 and sCD25 levels had worse overall and disease-related survivals, but only sCD30 retained significance in Cox models that included advanced age. High sCD30 also identified patients with worse survival in early MF. Increased IL-6 and IL-8 levels correlated with poor disease-related survival in CD30CLPD patients. We conclude that (1) neoplastic cells of some CD30CLPD patients do not resemble Th2 cells, and that (2) high serum sCD30, sCD25, IL-6, and perhaps IL-8 levels may provide prognostic information useful for patient management.

Nonsteroidal anti-inflammatory drugs induce apoptosis in cutaneous T-cell lymphoma cells and enhance their sensitivity for TNF-related apoptosis-inducing ligand

Cutaneous T-cell lymphomas (CTCL) form a heterogeneous group of non-Hodgkin's lymphomas of the skin. In previous studies, we had characterized CTCL cells as resistant to the death ligand tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), which correlated to pronounced expression of the caspase-8/-10 inhibitor c-FLIP. For identification of proapoptotic strategies in CTCL cells and for overcoming their death ligand resistance, we investigated the effects of nonsteroidal anti-inflammatory drugs (NSAIDs) such as acetylsalicylic acid, sodium salicylate, and diclofenac (DF). These drugs strongly enhanced apoptosis, as well as decreased CTCL cell proliferation and vitality, and DF furthermore sensitized for TRAIL-induced apoptosis. Full activation of the caspase cascade (caspase-3, -8, -9) and decreased mitochondrial membrane potential were characteristic for NSAID treatment, whereas cytochrome c release was seen only for DF. Downregulation of Mcl-1 and enhanced surface expression of TRAIL were seen in response to NSAIDs. Most characteristic for apoptosis induction was the downregulation of c-FLIP. In agreement with the critical role of c-FLIP for apoptosis deficiency of CTCL cells, its overexpression decreased NSAID-mediated apoptosis and its downregulation by small hairpin RNA-enhanced apoptosis. The study provides a rationale for the use of NSAIDs as a new therapeutic option for CTCL patients. Supporting this concept, ex vivo lymphoma cells of CTCL patients also revealed significant sensitivity for NSAID treatment.

Extrinsic apoptotic pathways: a new potential "target" for more sufficient therapy in a case of cutaneous anaplastic large cd30+ alk-T-cell lymphoma

The primary cutaneous T-cell lymphomas (CTCL) represent a clonal T-lymphocyte proliferation infiltrating the skin. CD30⁺T-cell lymphomas present clinically as nodules with a diameter between 1 and 15 cm, mostly in elderly patients. The role of the CD30 molecule in patients suffering from T-cell lymphomas is not completely clear yet. The signal transduction pathway which includes CD30 seems to play a key role in tumor progression. In certain forms of T-cellular lymphomas, the interaction between CD30/CD30-ligand is able to provoke apoptosis of the “tumor lymphocytes”. The modern conceptions of the pathogenesis of T-cell lymphomas include disorders in the pathways involved in programmed cellular death and disregulation in the expression of certain of its regulatory molecules. We are presenting an unusual case of a female patient with a primary cutaneous form of CD30⁺/ALK⁻ anaplastic large T-cell lymphoma. Upon the introduction of systemic PUVA, (psoralen plus ultraviolet light radiation) combined with beam therapy, a complete remission could be noticed. Eight months later, we observed a local recurrence, which was overcome by CHOP chemotherapy (Cyclophosphamide, Hydroxydaunorubicin (Doxorubicin), Vincristin (Oncovin®), Predniso(lo)n). Six months later, new cutaneous lesions had been noticed again. A new therapeutic hope for the patients with anaplastic large CTCL is actually based on the influence of the activity of the different apoptotic pathways. Death ligands, including tumor necrosis factor (TNF)-α, CD95L/FasL, and TRAIL, mediate also some important safeguard mechanisms against tumor growth in patients with CD30⁺ cutaneous anaplastic large T-cell lymphomas and critically contribute to lymphocyte homeostasis.

Anaplastic large cell lymphoma: twenty-five years of discovery

CONTEXT

The year 2010 commemorates the 25th year since the seminal publication by Karl Lennert and Harald Stein and others in Kiel, West Germany, describing an unusual large cell lymphoma now known as anaplastic large cell lymphoma (ALCL). Investigators at many universities and hospitals worldwide have contributed to our current in-depth understanding of this unique peripheral T-cell lymphoma, which in its systemic form, principally occurs in children and young adults.

OBJECTIVE

To summarize our current knowledge of the clinical and pathologic features of systemic and primary cutaneous ALCL. Particular emphasis is given to the biology and pathogenesis of ALCL.

DATA SOURCES

Search of the medical literature (Ovid MEDLINE In-Process & Other Non-Indexed Citations and Ovid MEDLINE: 1950 to Present [National Library of Medicine]) and more than 20 years of diagnostic experience were used as the source of data for review.

CONCLUSIONS

Based on immunostaining for activation antigen CD30 and the presence of dysregulation of the anaplastic lymphoma kinase gene (2p23), the diagnosis of ALCL has become relatively straightforward for most patients. Major strides have been made during the last decade in our understanding of the complex pathogenesis of ALCL. Constitutive NPM-ALK signaling has been shown to drive oncogenesis via an intricate network of redundant and interacting pathways that regulate cell proliferation, cell fate, and cytoskeletal modeling. Nevertheless, pathomechanistic, therapeutic, and diagnostic challenges remain that should be resolved as we embark on the next generation of discovery.

Enhanced death ligand-induced apoptosis in cutaneous SCC cells by treatment with diclofenac/hyaluronic acid correlates with downregulation of c-FLIP

Actinic keratosis (AK) occurs on sun-exposed skin and may progress to invasive squamous cell carcinoma (SCC). As for its topical treatment, diclofenac/hyaluronic acid (HA) has been recently approved. The NSAID diclofenac is an inhibitor of COX-2; however, its mode of action in cutaneous epithelial cancer cells is largely unknown. Here, the effects of diclofenac/HA were investigated in relation to death ligand-mediated apoptosis (TNF-alpha, TRAIL, and CD95 activation). Whereas diclofenac/HA only moderately induced apoptosis by itself, it resulted in pronounced enhancement of death ligand-mediated apoptosis in sensitive SCC cell lines (3/4). Apoptosis was associated with activation of initiator caspases of the extrinsic pathway (caspase-8/caspase-10). Furthermore, death ligand and diclofenac/HA-mediated apoptosis were blocked by the same caspase inhibitors, indicating related pathways. The proapoptotic effects of diclofenac/HA appeared independent of the p53 pathway. Also, upregulation of death receptors appeared less important; however, strong downregulation of c-FLIP isoforms was seen after diclofenac/HA treatment. The crucial role of c-FLIP was proven through overexpression and knockdown experiments. Thus, induction of apoptosis appears to be highly characteristic of the mode of action of diclofenac/HA, and the therapeutic effect may be related to sensitization of neoplastic keratinocytes for death ligand-induced apoptosis.