Peripheral T-cell lymphomas: a review of current approaches and hopes for the future

Pharmacological Inhibition of Oncogenic STAT3 and STAT5 Signaling in Hematopoietic Cancers

Signal Transducer and Activator of Transcription (STAT) 3 and 5 are important effectors of cellular transformation, and aberrant STAT3 and STAT5 signaling have been demonstrated in hematopoietic cancers. STAT3 and STAT5 are common targets for different tyrosine kinase oncogenes (TKOs). In addition, STAT3 and STAT5 proteins were shown to contain activating mutations in some rare but aggressive leukemias/lymphomas. Both proteins also contribute to drug resistance in hematopoietic malignancies and are now well recognized as major targets in cancer treatment. The development of inhibitors targeting STAT3 and STAT5 has been the subject of intense investigations during the last decade. This review summarizes the current knowledge of oncogenic STAT3 and STAT5 functions in hematopoietic cancers as well as advances in preclinical and clinical development of pharmacological inhibitors.

18F-FDG PET/CT imaging findings in anaplastic large cell lymphoma, a rare subtype of lymphoma

OBJECTIVE

To investigate the 18F-FDG PET/CT imaging manifestations for anaplastic large cell lymphoma (ALCL), a rare subtype of T/NK cell lymphoma.

METHODS

Fifty patients with ALCL, including 32 anaplastic lymphoma kinase (ALK)-positive patients and 18 ALK-negative patients, were enrolled. The positive detection, maximal standardized uptake value (SUVmax), and distribution of nodal and extranodal involvement were recorded and analysed. Fifty patients with diffuse large B cell lymphoma (DLBCL) were collected as a control group.

RESULTS

ALCL lesions were demonstrated to be 18F-FDG-avid tumours with a mean SUVmax of 19.4 ± 12.6. Most (76%) ALCL patients presented with stage III-IV disease, and nodal and extranodal involvement occurred in 74.0 and 72.0% of the patients, respectively. ALCL and DLBCL showed many similarities in tumour stage, 18F-FDG uptake and tumour involvement (P > 0.05), although the preferred extranodal organs of involvement (bone and the gastrointestinal tract, respectively) were different (P < 0.05). Compared to ALK-negative lesions, a higher uptake of 18F-FDG was found in the ALK-positive lesions (SUVmax: 22.1 ± 14.3 vs. 15.1 ± 6.6, t = 2.354, P = 0.023). ALK-positive ALCL was more likely to involve the lymph nodes than ALK-negative ALCL (84.3% vs. 55.5%, χ2 = 4.973, P = 0.043), while ALK-negative ALCL was more prone to involve the extranodal organs compared to ALK-positive ALCL (88.9% vs. 62.5%, χ2 = 3.979, P = 0.046).

CONCLUSION

The present study demonstrated that ALCL is a systemic 18F-FDG-avid lymphoma with many imaging manifestations similar to DLBCL on PET/CT. The present study also showed that ALK expression actually influenced tumour 18F-FDG uptake and lesion distribution. These findings may be useful to improve the understanding of the biological characteristics of ALCL.

Refractory Septic Shock due to Underlying Immunocompromised Disease: A Case of Fatal Peripheral T-Cell Lymphoma Not Otherwise Specified in a Young Hispanic Woman

Peripheral T-cell lymphoma not otherwise specified (PTCL-NOS) is known as an unclassified group of non-Hodgkin lymphomas. PTCL-NOS is a subtype of peripheral T-cell lymphoma that accounts for 3% of all lymphomas in the United States. PTCL-NOS commonly presents as a disseminated disease, B symptoms (fever, night sweats, and weight loss), generalized lymphadenopathy, bone marrow infiltration, and extranodal involvement. Other rare and possible manifestations include peripheral eosinophilia, pruritus, or hemophagocytic syndrome. This type of lymphoma is aggressive in nature and carries a high mortality rate. There is no established standard-of-care treatment protocol for PTCL-NOS, several chemotherapy drug combinations are frequently used as a frontline treatment with an overall 5-year survival rate of 25%. We present a case of a 35-year old Hispanic woman who initially presented with a chief complaint of bilateral lower extremity swelling due to hypoalbuminemia and new-onset hyperkeratotic skin of the palms and soles.

STAT5 inhibition induces TRAIL/DR4 dependent apoptosis in peripheral T-cell lymphoma

Peripheral T-cell lymphoma (PTCL) is a rare, aggressive, heterogeneous, Non-Hodgkin's lymphoma with poor prognosis and inadequate response to current therapies. Recent sequencing studies indicate a prevalence of activating mutations in the JAK/STAT signaling pathway. Oncogenic mutations in STAT5B, observed in approximately one third of cases of multiple different PTCL subtypes, correlate with inferior patient outcomes. Therefore, interest in the development of therapeutic strategies for targeting STAT5 in PTCL is warranted. In this study, we show that the drug pimozide inhibits STAT5 in PTCL, leading to apoptotic cell death by means of the TRAIL/DR4 dependent extrinsic apoptotic pathway. Pimozide induced PTCL cell death is caspase 8 dependent, increases the expression of the TRAIL receptor, DR4, on the surface of pre-apoptotic PTCL cells, and enhances TRAIL induced apoptosis in a TRAIL dependent manner. In parallel, we show that mRNA and protein levels of intrinsic pathway BCL-2 family members and mitochondrial membrane potential remain unaffected by STAT5 knockdown and/or inhibition. In primary PTCL patient samples, pimozide inhibits STAT5 activation and induces apoptosis. Our data support a role for STAT5 inhibition in PTCL and implicate potential utility for inhibition of STAT5 and activation of the extrinsic apoptotic pathway as combination therapy in PTCL.

Early diagnosis of an isolated primary peripheral T-cell lymphoma masquerading as massive gingival enlargement in a pediatric patient

Lymphomas are malignant neoplasm of the lymphocyte cell lines, classified as either Hodgkin's or non-Hodgkin's lymphoma (NHL). NHL comprises a heterogeneous group of lymphoid neoplasm arising from B-cell, T-cell or natural killer cell with a spectrum of behavior ranging from relatively indolent to highly aggressive and potentially fatal. Peripheral T-cell lymphoma, a variant of NHL, is a disease characterized by the presence of diffuse lymphadenopathy, extranodal involvement, classical B symptoms such as fever (>100.4°F) for 3 consecutive days, weight loss exceeding 10% of body weight in 6 months and drenching night sweats with a tendency for recurrence. Among NHLs, extranodal presentations are relatively common. Extranodal presentation particularly in the oral cavity is very rare and may misinterpret the diagnosis. Lesions of this type should be cautiously dealt especially in pediatric patients and young adolescents. The present case report is about an atypical presentation of disease process in a 15-year-old male patient, which was diagnosed early with the help of a combination of histopathology and immunohistochemistry techniques.

Concurrent Mutations in ATM and Genes Associated with Common γ Chain Signaling in Peripheral T Cell Lymphoma

Peripheral T cell lymphoma (PTCL) is a heterogeneous malignancy with poor response to current therapeutic strategies and incompletely characterized genetics. We conducted whole exome sequencing of matched PTCL and non-malignant samples from 12 patients, spanning 8 subtypes, to identify potential oncogenic mutations in PTCL. Analysis of the mutations identified using computational algorithms, CHASM, PolyPhen2, PROVEAN, and MutationAssessor to predict the impact of these mutations on protein function and PTCL tumorigenesis, revealed 104 somatic mutations that were selected as high impact by all four algorithms. Our analysis identified recurrent somatic missense or nonsense mutations in 70 genes, 9 of which contained mutations predicted significant by all 4 algorithms: ATM, RUNX1T1, WDR17, NTRK3, TP53, TRMT12, CACNA2D1, INTS8, and KCNH8. We observed somatic mutations in ATM (ataxia telangiectasia-mutated) in 5 out of the 12 samples and mutations in the common gamma chain (γc) signaling pathway (JAK3, IL2RG, STAT5B) in 3 samples, all of which also harbored mutations in ATM. Our findings contribute insights into the genetics of PTCL and suggest a relationship between γc signaling and ATM in T cell malignancy.

Preclinical targeting of human T-cell malignancies using CD4-specific chimeric antigen receptor (CAR)-engineered T cells

Peripheral T-cell lymphomas (PTCLs) are aggressive lymphomas with no effective upfront standard treatment and ineffective options in relapsed disease, resulting in poorer clinical outcomes as compared with B-cell lymphomas. The adoptive transfer of T cells engineered to express chimeric antigen receptors (CARs) is a promising new approach for treatment of hematological malignancies. However, preclinical reports of targeting T-cell lymphoma with CARs are almost non-existent. Here we have designed a CAR, CD4CAR, which redirects the antigen specificity of CD8+ cytotoxic T cells to CD4-expressing cells. CD4CAR T cells derived from human peripheral blood mononuclear cells and cord blood effectively redirected T-cell specificity against CD4+ cells in vitro. CD4CAR T cells efficiently eliminated a CD4+ leukemic cell line and primary CD4+ PTCL patient samples in co-culture assays. Notably, CD4CAR T cells maintained a central memory stem cell-like phenotype (CD8+CD45RO+CD62L+) under standard culture conditions. Furthermore, in aggressive orthotropic T-cell lymphoma models, CD4CAR T cells efficiently suppressed the growth of lymphoma cells while also significantly prolonging mouse survival. Combined, these studies demonstrate that CD4CAR-expressing CD8+ T cells are efficacious in ablating malignant CD4+ populations, with potential use as a bridge to transplant or stand-alone therapy for the treatment of PTCLs.

Targets, Toxins, and T Cells--a Review of New Monoclonal Antibodies in the Treatment of Peripheral T Cell Lymphomas

The peripheral T cell lymphomas (PTCLs) are a heterogeneous group of neoplasms for which standardized treatment approaches remain elusive. A number of new therapeutic agents have become available, of which monoclonal antibodies (MAbs) represent a powerful tool for targeted treatment of PTCLs. Therapeutic MAbs vary in their structure, targets, and mechanisms of action. Common mechanisms of action include antibody-dependent cell-mediated cytotoxicity, complement-dependent cytotoxicity, direct apoptosis, blocking of receptors or signaling pathways, delivery of cytotoxic agents to tumor cells, and binding to and blocking biologically active molecules. This review will focus on recent published evidence for the various MAbs used in the treatment of PTCLs. The results overall have been very promising, and the future will see more trials with these antibodies alone and in various therapy combinations, as well as newer ones with novel modifications, conjugates, and targets.

Persistent complete remission of acute leukemic-phase CCR4-positive gamma-delta peripheral T-cell lymphoma by autologous stem cell transplantation with mogamulizumab

Peripheral T-cell lymphoma, not otherwise specified (PTCL-NOS), frequently shows a poor outcome. Especially, expressions of CC chemokine receptor 4 (CCR4) and γδ T-cell receptor (TCR) are associated with worse prognosis in PTCL-NOS. We here report successful treatment with autologous peripheral blood stem cell transplantation (auto-PBSCT) combined with anti-CCR4 antibody mogamulizumab for a very rare case of CCR4+γδTCR+ PTCL-NOS that coexisted with Hodgkin's lymphoma. PTCL-NOS in this patient progressed to leukemic phase, whereas Hodgkin's lymphoma disappeared with standard chemotherapies within 4 years of the initial diagnosis. Leukemic-phase PTCL-NOS was refractory to several chemotherapies. However, auto-PBSCT following high-dose chemotherapy combined with pre- and post-transplant mogamulizumab, which is a humanized monoclonal antibody to CCR4, provided persistent complete remission of PTCL-NOS, despite residual γδTCR+ in the transplanted stem cell product, suggesting a purging effect of mogamulizumab. At 15 months after transplantation, we also found markedly fewer effector regulatory T cells, which may have contributed to prolonged remission. This case suggests that autologous stem cell transplantation combined with mogamulizumab may have a potential to cure T-cell neoplasms that express CCR4 including leukemic-phase PTCL-NOS.

Integrin αvβ3 acting as membrane receptor for thyroid hormones mediates angiogenesis in malignant T cells

The interaction of lymphoid tumor cells with components of the extracellular matrix via integrin αvβ3 allows tumor survival and growth. This integrin was demonstrated to be the membrane receptor for thyroid hormones (THs) in several tissues. We found that THs, acting as soluble integrin αvβ3 ligands, activated growth-related signaling pathways in T-cell lymphomas (TCLs). Specifically, TH-activated αvβ3 integrin signaling promoted TCL proliferation and angiogenesis, in part, via the upregulation of vascular endothelial growth factor (VEGF). Consequently, genetic or pharmacologic inhibition of integrin αvβ3 decreased VEGF production and induced TCL cell death in vitro and in human xenograft models. In sum, we show that integrin αvβ3 transduces prosurvival signals into TCL nuclei, suggesting a novel mechanism for the endocrine modulation of TCL pathophysiology. Targeting this mechanism could constitute an effective and potentially low-toxicity chemotherapy-free treatment of TCL patients.

Past, present and future treatment strategies in peripheral T-cell lymphomas

SUMMARY 

Nodal peripheral T-cell lymphomas (PTCLs) are very aggressive tumors characterized by poor response to conventional chemotherapy and dismal prognosis. Recent evidence has indicated that, at least for patients aged less than 60 years, frontline high-dose chemotherapy followed by autologous stem cell transplantation can be an effective strategy. Unfortunately, however, a significant fraction of patients cannot benefit from this approach, due to age, poor performance status or early relapse. In addition, a percentage of transplanted patients eventually relapse. In this article, based on their experience and on the most recent literature, the authors review the current concept on PTCL treatment, focusing on the most common PTCL nodal subtypes.

The changing landscape of peripheral T-cell lymphoma in the era of novel therapies

Peripheral T-cell lymphomas (PTCLs) are the most common sub-entity of mature T-cell lymphomas, and apart from particular presentations, share a poor prognosis with frequent short-term, agressive, and chemorefractory relapses. Because of the rarity and also the heterogeneity of the disease, we lack randomized clinical trials. However, to date, neither intensification of frontline chemotherapy or autologous transplant has led to any improvement of survival, and the standard CHOP (cyclophosphamide, doxorubicine, vincristine, and prednisone) regimen remains the most employed as induction therapy. In the past few years, new chemotherapeutic agents, with the capability to encompass the resistance to conventional chemotherapy, such as pralatrexate or bendamustine, have been evaluated. Furthermore, identification of cell surface molecular markers (CD52, CD30, CCR4) has led to the development of new monoclonal antibodies. Similarly, the better comprehension of physiopathological mechanisms and detection of deregulated intracellular pathways encouraged the use of novel therapies such as histone deacetylase inhibitors or immunomodulatory drugs. Some of these compounds have been approved for relapse, and are currently evaluated upfront in ongoing clinical trials. Despite these efforts, the global prognosis still remains much inferior to those of B-cell lymphomas, highlighting the necessity of multicenter clinical trials.