Alterations of negative regulators of cytokine signalling in immunodeficiency-related non-Hodgkin lymphoma

SHP1 loss augments DLBCL cellular response to ibrutinib: a candidate predictive biomarker

SHP1, a tyrosine phosphatase, negatively regulates B-cell receptor (BCR) signaling. Ibrutinib selectively inhibits BTK and has been approved for the treatment of several types of B-cell lymphomas, but not yet in diffuse large B-cell lymphoma (DLBCL). A phase 3 clinical trial of ibrutinib-containing regimen has been completed to evaluate its activity in subtypes or subsets of DLBCL patients. Although the subtype of activated B-cell like (ABC) DLBCL is characterized by chronic active BCR signaling, only a fraction of ABC-DLBCL patients seem to benefit from ibrutinib-containing regimen. New alternative predictive biomarkers are needed to identify patients who better respond. We investigated if SHP1 plays a role in defining the level of the BCR activity and impacts the response to ibrutinib. A meta-analysis revealed that lack of SHP1 protein expression as well as SHP1 promoter hypermethylation is strongly associated with NHL including DLBCL. On a tissue microarray of 95 DLBCL samples, no substantial difference in SHP1 expression was found between the GCB and non-GCB subtypes of DLBCL. However, we identified a strong reverse correlation between SHP1 expression and promoter methylation suggesting that promoter hypermethylation is responsible for SHP1 loss. SHP1 knockout in BCR-dependent GCB and ABC cell lines increased BCR signaling activities and sensitize lymphoma cells to the action of ibrutinib. Rescue of SHP1 in the knockout clones, on the other hand, restored BCR signaling and ibrutinib resistance. Further, pharmacological inhibition of SHP1 in both cell lines and patient-derived primary cells demonstrate that SHP1 inhibition synergized with ibrutinib in suppressing tumor cell growth. Thus, SHP1 loss may serve as an alternative biomarker to cell-of-origin to identify patients who potentially benefit from ibrutinib treatment. Our results further suggest that reducing SHP1 pharmacologically may represent a new strategy to augment tumor response to BCR-directed therapies. Schematic diagram summarizing the major findings. Left panel. When SHP1 is present and functional, it negatively regulates the activity of the BCR pathway. Right pane. When SHP1 is diminished or lost, cells depend more on the increased BCR signaling and making them vulnerable to BTK inhibitor, ibrutinib. Diagram was generated using BioRender.

Phenogenomic heterogeneity of post-transplant plasmablastic lymphomas

Plasmablastic lymphoma (PBL) is a rare and clinically aggressive neoplasm that typically occurs in immunocompromised individuals, including those infected with human immunodeficiency virus (HIV) and solid organ allograft recipients. Most prior studies have focused on delineating the clinico-pathological features and genetic attributes of HIVrelated PBL, in which MYC deregulation, Epstein-Barr virus (EBV) infection and, more recently, mutations in JAK/STAT, MAP kinase, and NOTCH pathway genes have been implicated in disease pathogenesis. The phenotypic spectrum of post-transplant (PT)-PBL is not well characterized and data on underlying genetic alterations are limited. This led us to perform comprehensive histopathological and immunophenotypic evaluation and targeted sequencing of 18 samples from 11 patients (8 males, 3 females; age range, 12-76 years) with PT-PBL; eight de novo and three preceded by other types of post-transplant lymphoproliferative disorders. Post-transplant PBL displayed morphological and immunophenotypic heterogeneity and some features overlapped those of plasmablastic myeloma. Six (55%) cases were EBV positive and five (45%) showed MYC rearrangement by fluorescence in situ hybridization. Recurrent mutations in epigenetic regulators (KMT2/MLL family, TET2) and DNA damage repair and response (TP53, mismatch repair genes, FANCA, ATRX), MAP kinase (KRAS, NRAS, HRAS, BRAF), JAK/STAT (STAT3, STAT6, SOCS1), NOTCH (NOTCH1, NOTCH3, SPEN), and immune surveillance (FAS, CD58) pathway genes were observed, with the mutational profiles of EBV⁺ and EBV^– cases exhibiting both similarities and differences. Clinical outcomes also varied, with survival ranging from 0-15.9 years after diagnosis. Besides uncovering the biological heterogeneity of PT-PBL, our study highlights similarities and distinctions between PT-PBL and PBL occurring in other settings and reveals potentially targetable oncogenic pathways in subsets of the disease.

DNA methylation alterations and their potential influence on macrophage in periodontitis

OBJECTIVES

To explore how various methylation mechanisms function and affect macrophages in periodontitis, with an aim of getting a comprehensive understanding of pathogenesis of the disease.

SUBJECT

Alterations in DNA methylation are associated with different periodontitis susceptible factors and disrupt immunity homeostasis. The host's immune response to stimulus plays a vital role in the progression of periodontitis. Macrophages are key immune cells of immune system. They act as critical regulators in maintaining issue homeostasis with their nature of high plasticity. The altered methylation status of genes may cause abnormal expression of proteins in the progress of periodontitis, thus, exert potential influence on macrophages.

RESULTS

Certain genes are selectively activated or silenced due to the changes in the methylation status, which causes the alteration of the expression level of cytokines/chemokines, signal molecules, extracellular matrix molecules, leads to the change in local microenvironment, affects activation states of immune cells including macrophages, thus influences the host immune response during periodontitis.. This results in differential susceptibility and therapeutic outcome.

CONCLUSION

DNA methylation alteration may cause aberrant expression level of genes associated with periodontal diseases, thus results in deregulation of macrophages, which supports the prospect of using DNA methylation-related parameter as a new biomarker for the diagnosis and treatment of periodontitis.

Curcumin Regulates Anti-Inflammatory Responses by JAK/STAT/SOCS Signaling Pathway in BV-2 Microglial Cells

Microglia play important physiological roles in central nervous system (CNS) homeostasis and in the pathogenesis of inflammatory brain diseases. Inflammation stimulates microglia to secrete cytokines and chemokines that guide immune cells to sites of injury/inflammation. Neuroinflammation is also strongly implicated in the pathogenesis of a number of neurodegenerative diseases, including Alzheimer’s disease and Parkinson’s disease, for which nutritional intervention could represent a benefit due to a lack of clinically efficacious drugs. To this end, the anti-inflammatory mechanisms of several phytochemicals, including curcumin, have been extensively studied. The present experiments show that the administration of curcumin is able to increase the production of the anti-inflammatory cytokines, IL-4 and IL-10, in murine BV-2 microglial cells treated with lipopolysaccharide (LPS). Consistent with these data, curcumin stimulation upregulates the expression of Suppressors of cytokine signaling (SOCS)-1, whereas phosphorylation of the JAK2 and STAT3 was reduced. Taken together, these results provide evidence that curcumin is able to regulate neuroinflammatory reactions by eliciting anti-inflammatory responses in microglia through JAK/STAT/SOCS signaling pathway modulation.

Downregulation of miR-152 contributes to DNMT1-mediated silencing of SOCS3/SHP-1 in non-Hodgkin lymphoma

Understanding the molecular mechanisms for the development of non-Hodgkin lymphoma (NHL) will improve our ability to cure the patients. qRT-PCR was applied for the examination of the efficiency of shRNA for DNMT1, the expression of suppressor genes, miRNA-152. The MTT analysis, cell cycle analysis, clonal formation, and apoptotic analysis were used to examine the functions of DNMT1 and miR-152 in lymphoma cells. Methylation-specific polymerase chain reaction (MSP) was used to examine the methylation of tumor suppressor genes. The dual luciferase assay and western blot were used to validate if DNMT1 is the target of miR-152. For the in vivo experiments, the lymphoma cells were injected into the nude mice for quantification of the tumor growth after transfection of miR-152 mimics. Knockdown of DNMT1 by shRNA (sh-DNMT1) in OCI-Ly10 and Granta-159 cells significantly upregulated the expression of tumor suppressor genes (SOCS3, BCL2L10, p16, p14, and SHP-1) via decreasing their methylation level. At the cellular level, we found sh-DNMT1 inhibited the proliferation, clonal formation and cell cycle progression and induced the cell apoptosis of lymphoma cells. Furthermore, we found miR-152 can downregulates the expression of DNMT1 via directly targeting the gene. Overexpression of miR-152 also increased the expression of tumor suppressor genes SOCS3 and SHP-1. And miR-152 also can inhibit the cell proliferation and induce the cell apoptosis. Moreover, we found overexpression of miR-152 significantly repressed the tumor growth with decreased DNMT1 expression and increased expression of tumor suppressor genes in vivo. Our study demonstrates that miR-152 can inhibit lymphoma growth via suppressing DNMT1-mediated silencing of SOCS3 and SHP-1. These data demonstrate a new mechanism for the development of NHL and this may provide a new therapeutic target for NHL.

Downregulated SOCS1 expression activates the JAK1/STAT1 pathway and promotes polarization of macrophages into M1 type

Macrophage polarization is flexible, and involves in different signaling pathways and various transcription factors. Suppressor of cytokine signaling (SOCS) is an important inhibitor of cytokine signaling pathways and also a key physiological regulator for natural and acquired immunity systems. Following transfection of SOCS1 short hairpin (sh)RNA into mouse macrophage cells, reverse transcription‑quantitative polymerase chain reaction demonstrated that the mRNA levels of Janus kinase (JAK)1 and signal transducer and activator of transcription (STAT)1 increased significantly. In addition, western blotting indicated that JAK1, STAT1 and p‑STAT1 expression was significantly enhanced. Fludarabine can inhibit phosphorylation of STAT1 and SOCS1 expression. When fludarabine was added and SOCS1 shRNA was transfected, the inhibition of fludarabine was weakened, and p‑STAT1 expression was upregulated. Flow cytometry detection indicated that, following the downregulation of SOCS1 expression, M1‑type cells significantly increased, but the proportion of M2‑type cells did not change significantly. Fludarabine can reduce the effect of SOCS1 shRNA on promoting M1‑type cell polarization, and macrophages can polarize into both M1 and M2 phenotypes. Further ELISA results presented that, when downregulating SOCS1 expression, interleukin (IL)‑4 and IL‑10 expression was both downregulated, and tumor necrosis factor (TNF)‑α and interferon (IFN)‑γ expression was significantly upregulated. When adding fludarabine or injecting with the traditional Chinese medicine Xuebijing, IL‑4 and IL‑10 expression was both significantly upregulated, and TNF‑α and IFN‑γ expression was significantly downregulated. When adding fludarabine and downregulating SOCS1, IL‑4, IL‑10, TNF‑α and IFN‑γ expression presented no significant changes. The above results indicated that, when SOCS1 expression is downregulated, it will activate the JAK1/STAT1 pathway, and thereby promote the polarization of macrophages into M1 type. The findings are of great importance for understanding occurrence, development and treatment of various immune‑related diseases.

MiR-30a increases MDSC differentiation and immunosuppressive function by targeting SOCS3 in mice with B-cell lymphoma

Myeloid-derived suppressor cells (MDSCs), including granulocytic (G)-MDSCs and monocytic (M)-MDSCs, play a critical role in tumor-induced T cell tolerance. MDSC immunosuppressive function and differentiation are significantly promoted in patients and B-cell lymphoma model mice. However, the mechanisms regulating these processes remain largely unclear. In the present study, we observed increased microRNA (miR)-30a expression both in G-MDSCs and in M-MDSCs from B cell lymphoma model mice. After transfection with miR-30a mimics, the differentiation and suppressive capacities of MDSCs were significantly increased via up-regulation of arginase-1. Moreover, we showed that the 3'-UTR of suppressor of cytokine signaling 3 (SOCS3) mRNA is a direct target of miR-30a. Decreased SOCS3 expression and activated Janus kinase-signal transducer and activator of transcription 3 signaling promote MDSC differentiation and suppressive activities. These findings provide new insights into the molecular mechanisms underlying MDSC expansion and function during B cell lymphoma development.

TC-PTP and PTP1B: Regulating JAK-STAT signaling, controlling lymphoid malignancies

Lymphoid malignancies are characterized by an accumulation of genetic lesions that act co-operatively to perturb signaling pathways and alter gene expression programs. The Janus kinases (JAK)-signal transducers and activators of transcription (STATs) pathway is one such pathway that is frequently mutated in leukemia and lymphoma. In response to cytokines and growth factors, a cascade of reversible tyrosine phosphorylation events propagates the JAK-STAT pathway from the cell surface to the nucleus. Activated STAT family members then play a fundamental role in establishing the transcriptional landscape of the cell. In leukemia and lymphoma, somatic mutations have been identified in JAK and STAT family members, as well as, negative regulators of the pathway. Most recently, inactivating mutations in the protein tyrosine phosphatase (PTP) genes PTPN1 (PTP1B) and PTPN2 (TC-PTP) were sequenced in B cell lymphoma and T cell acute lymphoblastic leukemia (T-ALL) respectively. The loss of PTP1B and TC-PTP phosphatase activity is associated with an increase in cytokine sensitivity, elevated JAK-STAT signaling, and changes in gene expression. As inactivation mutations in PTPN1 and PTPN2 are restricted to distinct subsets of leukemia and lymphoma, a future challenge will be to identify in which cellular contexts do they contributing to the initiation or maintenance of leukemogenesis or lymphomagenesis. As well, the molecular mechanisms by which PTP1B and TC-PTP loss co-operates with other genetic aberrations will need to be elucidated to design more effective therapeutic strategies.

Mutations and chromosomal rearrangements of JAK2: not only a myeloid issue

Until today, JAK2 alterations have been mainly associated with myeloid malignancies among which they play a key pathogenic role in chronic myeloproliferative neoplasms. More recently, aberrations involving the JAK2 gene have also been reported in lymphoid diseases, including acute leukemia and lymphomas. In addition, the constitutively activating JAK2V617F mutation has been identified in some patients affected by B-chronic lymphocytic leukemia with a concomitant myeloproliferative neoplasm. Interestingly, these cases could help us to better understand the pathogenesis of these myeloid and lymphoid diseases and reveal if they share a common ancestral progenitor or just coincide. The involvement of JAK2 in lymphoid neoplasms may suggest the possibility of new therapeutic approaches broadening the use of JAK1-2 inhibitors also to these malignancies.

The role of suppressors of cytokine signalling in human neoplasms

Suppressors of cytokine signalling 1-7 (SOCS1-7) and cytokine-inducible SH2-containing protein (CIS) are a group of intracellular proteins that are well known as JAK-STAT and several other signalling pathways negative feedback regulators. More recently several members have been identified as tumour suppressors and dysregulation of their biological roles in controlling cytokine and growth factor signalling may contribute to the development of many solid organ and haematological malignancies. This review explores their biological functions and their possible tumour suppressing role in human neoplasms.

SOCS1 hypermethylation mediated by DNMT1 is associated with lipopolysaccharide-induced inflammatory cytokines in macrophages

Macrophages activation which releases the pro-inflammatory cytokines is an essential event in the process of inflammation. SOCS1 has been shown to act as a negative regulator of cytokine signals and plays a key role in the suppression of tissue injury and inflammatory diseases. DNA methylation mediated by specific DNA methyltransferases1 (DNMT1) which contributes to the epigenetic silencing of multiple genes. SOCS1 promoter hypermethylation is by far the best categorized epigenetic change in tumors. Our study with a view to investigate whether the loss of SOCS1 due to SOCS1 promoter methylation was involved in the course of inflammatory cytokines released from lipopolysaccharide (LPS)-stimulated macrophages. Here, we found that treatment of LPS-induced RAW264.7 macrophage cells with the DNA methylation inhibitor 5-aza-2'-deoxycytidine (5-azadC) reduced aberrant promoter hypermethylation of SOCS1 and prevented the loss of the expression of SOCS1 in macrophages which secret inflammatory cytokines. Knockdown of DNMT1 gene not only attenuated the SOCS1 gene promoter methylation but also up-regulated the expression of SOCS1 in activated RAW264.7 cells. Furthermore, silencing of DNMT1 prevented the activation of JAK2/STAT3 pathway in LPS-induced RAW264.7 cells. These studies demonstrated that DNMT1-mediated SOCS1 hypermethylation caused the loss of SOCS1 expression results in negative regulation of activation of the JAK2/STAT3 pathway, and enhanced the release of LPS-induced pro-inflammatory cytokines such as TNF-α and IL-6 in macrophages.

SOCS1 mutation subtypes predict divergent outcomes in diffuse large B-Cell lymphoma (DLBCL) patients

Suppressor of cytokine signaling 1 (SOCS1) is frequently mutated in primary mediastinal and diffuse large B-cell lymphomas (DLBCL). Currently, the prognostic relevance of these mutations in DLBCL is unknown. To evaluate the value of the SOCS1 mutation status as a prognostic biomarker in DLBCL patients, we performed full-length SOCS1 sequencing in tumors of 154 comprehensively characterized DLBCL patients. We identified 90 SOCS1 mutations in 16% of lymphomas. With respect to molecular consequences of mutations, we defined two distinct subtypes: those with truncating (major) and those with non-truncating mutations (minor), respectively. The SOCS1 mutated subgroup or the minor/major subtypes cannot be predicted on clinical grounds; however, assignment of four established gene-expression profile-based classifiers revealed significant associations of SOCS1 major cases with germinal center and specific pathway activation pattern signatures. Above all, SOCS1 major cases have an excellent overall survival, even better than the GCB-like subgroup. SOCS1 minor cases had a dismal survival, even worse than the ABC gene signature group. The SOCS1 mutation subsets retained prognostic significance in uni- and multivariate analyses. Together our data indicate that assessment of the SOCS1 mutation status is a single gene prognostic biomarker in DLBCL.

Critical analysis of the potential for targeting STAT3 in human malignancy

The signal transducer and activator of transcription (STAT) family of proteins was originally discovered in the context of normal cell biology where they function to transduce intracellular and extracellular signals to the nucleus, ultimately leading to transcription of specific target genes and downstream phenotypic effects. It was quickly appreciated that the STATs, especially STAT3, play a fundamental role in human malignancy. In contrast to normal biology in which transient STAT3 signaling is strictly regulated by a tightly coordinated network of activators and deactivators, STAT3 is constitutively activated in human malignancies. Constitutive STAT3 signaling has been associated with many cancerous phenotypes across nearly all human cancers, including the upregulation of cell growth, proliferation, survival, and motility, among others. Studies involving candidate preclinical STAT3 inhibitors have further demonstrated that the reversal of these phenotypes results from pharmacologic or genetic inhibition of STAT3, suggesting that STAT3 may be a promising target for clinical interventions. Indeed, a Phase 0 clinical trial involving a STAT3 decoy oligonucleotide demonstrated that STAT3 is a drug-gable target in human tumors. Because of the ubiquity of overactive STAT3 in cancer, its role in promoting a wide variety of cancerous phenotypes, and the strong clinical and preclinical studies performed to date, STAT3 represents a promising target for the development of inhibitors for the treatment of human cancers.