Preclinical investigation of new targeted combination therapies in cutaneous T-cell lymphoma
Poster
Sézary syndrome (SS), the leukemic variant of cutaneous T cell lymphoma (CTCL), shows high relapse rates and poor prognosis, which complicates the clinical course as well as the treatment. The circulating atypical T cells known as Sézary cells (SC) display a CD4+/CD8- T helper cell phenotype. A diagnostic marker profile of SC is defined by loss of CD7 and/or CD26 and increased CD158k expressions.
Due to frequent relapses and treatment-related side effects of current therapies as well as progressive therapy resistance of SS, there is an urgent need for the development of effective and well-tolerated therapeutic options.
Dimethyl fumarate (DMF) is a potent NFκB inhibitor and is being used in a clinical phase 2 study for CTCL patients. Our group has shown that DMF induces apoptosis, specifically in malignant CTCL cells while sparing the healthy T cells. Extracorporeal photopheresis (ECP) is an established standard treatment for erythrodermic CTCL such as SS.
We found in 3 SS patients that the new targeted combination therapy of DMF and ECP (in part with interferon-alpha) decreased the SC count drastically. All of these patients had received ECP and DMF separately as monotherapies before receiving the combination therapy, but had developed a resistance. However, with the combination therapy approach patients had long-term complete remissions in the blood and the interval between therapies, a parameter for the efficacy and tolerability of the treatment, was at least 3 times higher than for all other CTCL therapies.
In light of these interesting clinical findings, our aim is to investigate ECP and DMF as a novel combined therapy in CTCL cell lines and patient derived CD4+ T cells and understand their synergistic effects based on immunomodulation and cell death. Hence, the underlying cellular and molecular mechanisms of this new therapeutic approach will be identified.
CD4+ T cells isolated from peripheral blood monocytes of SS patients as well as the CTCL cell lines SeAx, HH and Hut-78 were treated ex vivo with UVA to mimic ECP therapy in combination with DMF treatment. SS patient cells show different cell death responses to the combination treatment depending on the previous therapies that the patients received. Additionally, in CTCL cell lines combination treatment led to distinctive cell death patterns as consequence of different signaling pathways and alterations that they represent.
We will further study the synergistic mechanism of the combination treatment and unveil involved pathways by performing single cell RNA sequencing analysis of CTCL patient cells and RNA sequencing analysis in cell lines. Furthermore, activity of NFKB subunits and the cytokine profile present in the serum of patients will be investigated before and after the combination treatment. In addition, we aim to study this combinatory effect also in vivo in a CTCL mouse model in order to eventually translate it into a clinical study.
Due to frequent relapses and treatment-related side effects of current therapies as well as progressive therapy resistance of SS, there is an urgent need for the development of effective and well-tolerated therapeutic options.
Dimethyl fumarate (DMF) is a potent NFκB inhibitor and is being used in a clinical phase 2 study for CTCL patients. Our group has shown that DMF induces apoptosis, specifically in malignant CTCL cells while sparing the healthy T cells. Extracorporeal photopheresis (ECP) is an established standard treatment for erythrodermic CTCL such as SS.
We found in 3 SS patients that the new targeted combination therapy of DMF and ECP (in part with interferon-alpha) decreased the SC count drastically. All of these patients had received ECP and DMF separately as monotherapies before receiving the combination therapy, but had developed a resistance. However, with the combination therapy approach patients had long-term complete remissions in the blood and the interval between therapies, a parameter for the efficacy and tolerability of the treatment, was at least 3 times higher than for all other CTCL therapies.
In light of these interesting clinical findings, our aim is to investigate ECP and DMF as a novel combined therapy in CTCL cell lines and patient derived CD4+ T cells and understand their synergistic effects based on immunomodulation and cell death. Hence, the underlying cellular and molecular mechanisms of this new therapeutic approach will be identified.
CD4+ T cells isolated from peripheral blood monocytes of SS patients as well as the CTCL cell lines SeAx, HH and Hut-78 were treated ex vivo with UVA to mimic ECP therapy in combination with DMF treatment. SS patient cells show different cell death responses to the combination treatment depending on the previous therapies that the patients received. Additionally, in CTCL cell lines combination treatment led to distinctive cell death patterns as consequence of different signaling pathways and alterations that they represent.
We will further study the synergistic mechanism of the combination treatment and unveil involved pathways by performing single cell RNA sequencing analysis of CTCL patient cells and RNA sequencing analysis in cell lines. Furthermore, activity of NFKB subunits and the cytokine profile present in the serum of patients will be investigated before and after the combination treatment. In addition, we aim to study this combinatory effect also in vivo in a CTCL mouse model in order to eventually translate it into a clinical study.