The Therapeutic Potential of AN-7, a Novel Histone Deacetylase Inhibitor, for Treatment of Mycosis Fungoides/Sezary Syndrome Alone or with Doxorubicin

Retrospective Analysis of 118 Patients With Cutaneous T-Cell Lymphomas: A Single-Center Experience

Cutaneous T-cell lymphomas (CTCL) represent rare non-Hodgkin lymphomas (NHL) with an incidence less than 1 per 100,000 inhabitants. The most common type of CTCL is mycosis fungoides (MF), which represents approximately 60% of all CTCL, followed by Sézary syndrome (SS), approximately 5%. We retrospectively analyzed the outcome of 118 patients with MF (n=96) and SS (n=22) treated between the years 1998 and 2021 at the Charles University General Hospital in Prague, Czech Republic. The ratio between men and women was 1.2:1 (62 men, and 56 women). The median age at diagnosis was 62 years (23 to 92 years). From the MF cohort 48 patients (50% out of MF cohort) presented with advanced stage disease. Ninety patients (77%) received a systemic treatment at any time from the diagnosis; the median number of therapy lines was two. At the time of database lock, the overall survival (OS) of 96 patients with MF reached 17.7 years with the median follow-up 4.0 years. With the median follow-up 2.6 years, the median OS of 22 patients with SS was 3.5 years. The most common type of systemic therapy for MF included low-dose methotrexate (61%), interferon-alpha (58%), bexarotene (28%), and chlorambucil (25%). The most common type of therapy for SS included bexarotene (64%), extracorporeal photopheresis (50%), and interferon-alpha (45%). Only the minority of patients received innovative targeted agents including brentuximab vedotin, mogamulizumab, or pembrolizumab. Besides the retrospective analysis of the CTCL cohort, current standards and future perspectives of selected innovative agents are summarized and discussed. The analyzed cohort represents the largest cohort of CTCL patients in the Czech Republic. Overall, the survival parameters of our CTCL cohort are comparable to those previously published by other groups. In conclusion, our analysis of 118 real world cohort of consecutive CTCL patients treated at the single center confirmed the efficacy of immune response modifiers and underlines the urgent need for ample implementation of innovative agents and their combinations into earlier lines of therapy.

Jak-STAT Inhibition Mediates Romidepsin and Mechlorethamine Synergism in Cutaneous T-Cell Lymphoma

Sézary syndrome is an aggressive and disseminated form of cutaneous T-cell lymphoma associated with dismal prognosis in which the histone deacetylase inhibitor romidepsin has shown remarkable activity as a single agent. However, clinical responses to romidepsin are typically transient, highlighting the need for more effective therapies. In this study, we show synergistic antilymphoma effects of romidepsin in combination with mechlorethamine, an alkylating agent, in cutaneous T-cell lymphoma cell lines and primary samples with strong antitumor effects in an in vivo model of Sézary syndrome. Mechanistically, gene expression profiling points to abrogation of Jak/signal transducer and activator of transcription (STAT) signaling as an important mediator of this interaction. Consistently, the combination of mechlorethamine plus romidepsin resulted in downregulation of STAT5 phosphorylation in romidepsin-sensitive cell lines and primary Sézary syndrome samples, but not in romidepsin-resistant tumors. Moreover, in further support of Jak/STAT signaling as a modulator of romidepsin activity in cutaneous T-cell lymphoma, treatment with romidepsin in combination with Jak inhibitors resulted in markedly increased therapeutic responses. Overall, these results support a role for romidepsin plus mechlorethamine in combination in the treatment of cutaneous T-cell lymphoma and uncover a previously unrecognized role for Jak/STAT signaling in the response to romidepsin and romidepsin-based combination therapies in Sézary syndrome.

Xenograft and cell culture models of Sézary syndrome reveal cell of origin diversity and subclonal heterogeneity

Sézary Syndrome (SS) is a rare aggressive epidermotropic cutaneous T-cell lymphoma (CTCL) defined by erythroderma, pruritis, and a circulating atypical CD4 + T-cell clonal population. The diversity of Sézary cell (SC) phenotype and genotype may reflect either plasticity or heterogeneity, which was difficult to evaluate dynamically until the achievement of long-term SC expansion. Therefore, we developed six defined culture conditions allowing for the expansion of SC defined by their phenotype and monoclonality in four of seven SS cases. Engraftment of SC through the intrafemoral route into immunodeficient NOD.Cg-Prkdc(scid)Il2rg(tm1Wjll)/SzJ (NSG) mice was achieved in 2 of 14 SS cases. Secondary xenograft by percutaneous injection mimicked most of the features of SS with dermal infiltration, epidermotropism, and blood spreading. These models also allowed assessing the intra-individual heterogeneity of patient SC. Subclones sharing the same TCR gene rearrangement evolved independently according to culture conditions and/or after xenografting. This clonal selection was associated with some immunophenotypic plasticity and limited genomic evolution both in vitro and in vivo. The long-term amplification of SC allowed us to develop eight new SC lines derived from four different patients. These lines represent the cell of origin diversity of SC and provide new tools to evaluate their functional hallmarks and response to therapy.

Celecoxib Prevents Doxorubicin-Induced Multidrug Resistance in Canine and Mouse Lymphoma Cell Lines

Background: Treatment of malignancies is still a major challenge in human and canine cancer, mostly due to the emergence of multidrug resistance (MDR). One of the main contributors of MDR is the overexpression P-glycoprotein (Pgp), which recognizes and extrudes various chemotherapeutics from cancer cells. Methods: To study mechanisms underlying the development of drug resistance, we established an in vitro treatment protocol to rapidly induce Pgp-mediated MDR in cancer cells. Based on a clinical observation showing that a 33-day-long, unplanned drug holiday can reverse the MDR phenotype of a canine diffuse large B-cell lymphoma patient, our aim was to use the established assay to prevent the emergence of drug resistance in the early stages of treatment. Results: We showed that an in vitro drug holiday results in the decrease of Pgp expression in MDR cell lines. Surprisingly, celecoxib, a known COX-2 inhibitor, prevented the emergence of drug-induced MDR in murine and canine lymphoma cell lines. Conclusions: Our findings suggest that celecoxib could significantly improve the efficiency of chemotherapy by preventing the development of MDR in B-cell lymphoma.

Cutaneous T Cell Lymphoma: A Difficult Diagnosis Demystified

Cutaneous T cell lymphoma (CTCL) represents a heterogeneous group of extranodal non-Hodgkin lymphomas in which monoclonal T lymphocytes infiltrate the skin. The mechanism of CTCL development is not fully understood, but likely involves dysregulation of various genes and signaling pathways. A variety of treatment modalities are available, and although they can induce remission in most patients, the disease may recur after treatment cessation. Owing to relatively low incidence and significant chronicity of disease, and the high morbidity of some therapeutic regimens, further clinical trials are warranted to better define the ideal treatment option for each subtype of CTCL.

Histone Deacetylases (HDACs) Guided Novel Therapies for T-cell lymphomas

T-cell lymphomas are a heterogeneous group of cancers with different pathogenesis and poor prognosis. Histone deacetylases (HDACs) are epigenetic modifiers that modulate many key biological processes. In recent years, HDACs have been fully investigated for their roles and potential as drug targets in T-cell lymphomas. In this review, we have deciphered the modes of action of HDACs, HDAC inhibitors as single agents, and HDACs guided combination therapies in T-cell lymphomas. The overview of HDACs on the stage of T-cell lymphomas, and HDACs guided therapies both as single agents and combination regimens endow great opportunities for the cure of T-cell lymphomas.

Cutaneous T-cell lymphomas: modern data of pathogenesis, clinics and therapy

Cutaneous T-cell lymphomas (CTCL) are a heterogeneous group of extranodal non-Hodgkin’s lymphomas that are characterized by skin infiltration with malignant monoclonal T lymphocytes. More common in adults aged 55 to 60 years, the annual incidence is about 0.5 per 100 000 people. Mycosis fungoides, Sézary syndrome and CD30+ lymphoproliferative diseases are the main subtypes of CTCL. To date, CTCL have a complex concept of etiopathogenesis, diagnosis, therapy and prognosis. The article presented summary data on these issues.

AN-7, a butyric acid prodrug, sensitizes cutaneous T-cell lymphoma cell lines to doxorubicin via inhibition of DNA double strand breaks repair

We previously found that the novel histone deacetylase inhibitor (HDACI) butyroyloxymethyl diethylphosphate (AN-7) had greater selectivity against cutaneous T-cell lymphoma (CTCL) than SAHA. AN-7 synergizes with doxorubicin (Dox), an anthracycline antibiotic that induces DNA breaks. This study aimed to elucidate the mechanism underlying the effect of AN-7 on Dox-induced double-strand DNA breaks (DSBs) in CTCL, MyLa and Hut78 cell lines. The following markers/assays were employed: comet assay; western blot of γH2AX and p-KAP1; immunofluorescence of γH2AX nuclear foci; Western blot of repair protein; quantification of DSBs-repair through homologous recombination. DSB induction by Dox was evidenced by an increase in DSB markers, and DSBs-repair, by their subsequent decrease. The addition of AN-7 slightly increased Dox induction of DSBs in MyLa cells with no effect in Hut78 cells. AN-7 inhibited the repair of Dox-induced DSBs, with a more robust effect in Hut78. Treatment with AN-7 followed by Dox reduced the expression of DSB-repair proteins, with direct interference of AN-7 with the homologous recombination repair. AN-7 sensitizes CTCL cell lines to Dox, and when combined with Dox, sustains unrepaired DSBs by suppressing repair protein expression. Our data provide a mechanistic rationale for combining AN-7 with Dox or other DSB inducers as a therapeutic modality in CTCL.

An overview of cutaneous T cell lymphomas

Cutaneous T cell lymphomas (CTCLs) are a heterogeneous group of extranodal non-Hodgkin’s lymphomas that are characterized by a cutaneous infiltration of malignant monoclonal T lymphocytes. They typically afflict adults with a median age of 55 to 60 years, and the annual incidence is about 0.5 per 100,000. Mycosis fungoides, Sézary syndrome, and primary cutaneous peripheral T cell lymphomas not otherwise specified are the most important subtypes of CTCL. CTCL is a complicated concept in terms of etiopathogenesis, diagnosis, therapy, and prognosis. Herein, we summarize advances which have been achieved in these fields.