IL-6-induced STAT3 or STAT5 activation is a critical mechanism underlying PI3K inhibitor resistance in lymphoma, supporting the utility of IL-6 as an effective biomarker to predict therapeutic response to PI3K inhibitors.
While each malignancy within this group is characterized by unique clinicopathologic features, dysregulation in the Janus tyrosine family of kinases/Signal transducer and activator of transcription (JAK/STAT) signaling pathway, specifically aberrant STAT3 activation, is a common feature among these lymphomas.
These findings suggest that combined expression of p-ERK, MYC, and p-STAT3 is a useful immunohistochemical pattern for the diagnosis of EZH2-positive Hodgkin lymphomas and related lymphomas, in contrast to ABCLs.
Patients with loss-of-function (LOF) signal transducer and activator of transcription 3 (STAT3) mutations have dermatitis, enhanced IgE production despite a relative lack of immediate hypersensitivity, recurrent infection, and an increased rate of lymphoma in addition to a number of skeletal and connective tissue abnormalities.
Mutated STAT3 is mainly associated with large granular lymphocytic T-cell leukemia, whereas mutated STAT5B is associated with T-cell prolymphocytic leukemia, T-cell acute lymphoblastic leukemia and γδ T-cell-derived lymphomas.
Lymphomas in this model lacking Tyk2 have reduced STAT1 and STAT3 phosphorylation and reduced expression of Mcl1, a pro-survival member of the BCL2 family.
Blocking either STAT3 or IL-10 could significantly increase the susceptibility of MYD88 L265P mutant lymphomas toward CD8<sup>+</sup> T cell-mediated cytotoxicity.
When neonatal B-1 B1a cells express an antithymocyte/Thy-1 autoreactivity (ATA) BCR transgene in the C.B17 mouse background, ATA B cells increase in PBL and strongly develop lymphomas in aging mice that feature splenomegaly and mLN hyperplasia with heightened expression of CD11b, IL-10, and activated Stat3.
With the use of BTK and STAT3 inhibitors to treat B cell lymphomas in clinical trials, these findings highlight the possibility of using new pharmaceutical approaches to treat EBV-associated lymphomas that express LMP2A.
Accordingly, the combination of THZ1 and the BH3 mimetic obatoclax improves lymphoma growth control in a primary PTCL ex vivo culture and in two STAT3-mutant PTCL xenografts, delineating a potential targeted agent-based therapeutic option for these patients.
Top hits were further validated with additional models including STAT3-mutated natural killer (NK)-cell leukemia/lymphoma cell lines and primary large granular lymphocytic (LGL) leukemia cells to assess their ability to inhibit STAT3 phosphorylation and STAT3 dependent cell viability.
Although the significance of PD-L1/2 expressions on macrophages in lymphoma progression has never been clarified, an IL-27-Stat3 axis might be a target for immunotherapy for lymphoma patients.
Doxorubicin resistant Dalton's lymphoma is susceptible to dendritic cell derived TNF-α upon stimulation with the STAT3 inhibitor cucurbitacin-I, which downregulates STAT3 and other survival molecules.
Systemic delivery of the unformulated ASO, AZD9150, decreased STAT3 expression in a broad range of preclinical cancer models and showed antitumor activity in lymphoma and lung cancer models.
However, STAT3 activation is a key oncogenic pathway in natural killer (NK)-lineage large granular lymphomas, and we recently reported enhanced proliferation and function of human NK cells activated with IL-21, which signals primarily through STAT3.
Our investigation of the mechanisms underlying the decrease in miR-26a in this lymphoma revealed novel evidence that STAT3, a major downstream substrate of NPM-ALK tyrosine kinase activity, suppresses MIR26A1 gene expression.
In adolescence, three AD-HIES patients without STAT3 mutation died of myocardial infarction, staphylococcus sepsis, and proteus sepsis while receiving chemotherapy for lymphoma.
In vitro, Tim-3(+) ECs modulated T cell response to lymphoma surrogate antigens by suppressing activation of CD4(+) T lymphocytes through the activation of the interleukin-6-STAT3 pathway, inhibiting Th1 polarization, and providing protective immunity.