Epigenetic dysregulation of eukaryotic initiation factor 3 subunit E (eIF3E) by lysine methyltransferase REIIBP confers a pro-inflammatory phenotype in t(4;14) myeloma

REIIBP is a lysine methyltransferase aberrantly expressed through alternative promoter usage of NSD2 locus in t(4;14)-translocated multiple myeloma (MM). Clinically, t(4;14) translocation is an adverse prognostic factor found in approximately 15% of MM patients. The contribution of REIIBP relative to other NSD2 isoforms as a dependency gene in t(4;14)-translocated MM remains to be evaluated. Here, we demonstrated that despite homology with NSD2, REIIBP displayed distinct substrate specificity by preferentially catalyzing H3K4me3 and H3K27me3, with little activity on H3K36me2. Furthermore, REIIBP was regulated through microRNAs by EZH2 in a Dicer-dependent manner, exemplifying a role of REIIBP in SET-mediated H3K27me3. ChIP-sequencing revealed chromatin remodeling characterized by changes in genome-wide and loci-specific occupancy of these opposing histone marks, allowing a bidirectional regulation of its target genes. Transcriptomics indicated that REIIBP induced a pro-inflammatory gene signature through upregulation of TLR7, which in turn led to B-cell receptor (BCR)-independent activation of BTK and driving NFĸB-mediated production of cytokines such as IL-6. Activation of this pathway is targetable using Ibrutinib and partially mitigated bortezomib resistance in an REIIBP xenograft model. Mechanistically, REIIBP upregulated TLR7 through eIF3E, and this relied on eIF3E RNA-binding function instead of its canonical protein synthesis activity, as demonstrated by direct binding to the 3'UTR of TLR7 mRNA. Altogether, we provided a rationale that coexistence of different NSD2 isoforms induced diversified oncogenic programs that should be considered in the strategies for t(4;14)-targeted therapy.

Super-enhancer-driven TOX2 mediates oncogenesis in Natural Killer/T Cell Lymphoma

BACKGROUND

Extranodal natural killer/T-cell lymphoma (NKTL) is an aggressive type of non-Hodgkin lymphoma with dismal outcome. A better understanding of disease biology and key oncogenic process is necessary for the development of targeted therapy. Super-enhancers (SEs) have been shown to drive pivotal oncogenes in various malignancies. However, the landscape of SEs and SE-associated oncogenes remain elusive in NKTL.

METHODS

We used Nano-ChIP-seq of the active enhancer marker histone H3 lysine 27 acetylation (H3K27ac) to profile unique SEs NKTL primary tumor samples. Integrative analysis of RNA-seq and survival data further pinned down high value, novel SE oncogenes. We utilized shRNA knockdown, CRISPR-dCas9, luciferase reporter assay, ChIP-PCR to investigate the regulation of transcription factor (TF) on SE oncogenes. Multi-color immunofluorescence (mIF) staining was performed on an independent cohort of clinical samples. Various function experiments were performed to evaluate the effects of TOX2 on the malignancy of NKTL in vitro and in vivo.

RESULTS

SE landscape was substantially different in NKTL samples in comparison with normal tonsils. Several SEs at key transcriptional factor (TF) genes, including TOX2, TBX21(T-bet), EOMES, RUNX2, and ID2, were identified. We confirmed that TOX2 was aberrantly overexpressed in NKTL relative to normal NK cells and high expression of TOX2 was associated with worse survival. Modulation of TOX2 expression by shRNA, CRISPR-dCas9 interference of SE function impacted on cell proliferation, survival and colony formation ability of NKTL cells. Mechanistically, we found that RUNX3 regulates TOX2 transcription by binding to the active elements of its SE. Silencing TOX2 also impaired tumor formation of NKTL cells in vivo. Metastasis-associated phosphatase PRL-3 has been identified and validated as a key downstream effector of TOX2-mediated oncogenesis.

CONCLUSIONS

Our integrative SE profiling strategy revealed the landscape of SEs, novel targets and insights into molecular pathogenesis of NKTL. The RUNX3-TOX2-SE-TOX2-PRL-3 regulatory pathway may represent a hallmark of NKTL biology. Targeting TOX2 could be a valuable therapeutic intervene for NKTL patients and warrants further study in clinic.

Super Enhancer-Mediated Upregulation of HJURP Promotes Growth and Survival of t(4;14)-Positive Multiple Myeloma

Multiple myeloma is an incurable malignancy with marked clinical and genetic heterogeneity. The cytogenetic abnormality t(4;14) (p16.3;q32.3) confers aggressive behavior in multiple myeloma. Recently, essential oncogenic drivers in a wide range of cancers have been shown to be controlled by super-enhancers (SE). We used chromatin immunoprecipitation sequencing of the active enhancer marker histone H3 lysine 27 acetylation (H3K27ac) to profile unique SEs in t(4;14)-translocated multiple myeloma. The histone chaperone HJURP was aberrantly overexpressed in t(4;14)-positive multiple myeloma due to transcriptional activation by a distal SE induced by the histone lysine methyltransferase NSD2. Silencing of HJURP with short hairpin RNA or CRISPR interference of SE function impaired cell viability and led to apoptosis. Conversely, HJURP overexpression promoted cell proliferation and abrogated apoptosis. Mechanistically, the NSD2/BRD4 complex positively coregulated HJURP transcription by binding the promoter and active elements of its SE. In summary, this study introduces SE profiling as an efficient approach to identify new targets and understand molecular pathogenesis in specific subtypes of cancer. Moreover, HJURP could be a valuable therapeutic target in patients with t(4;14)-positive myeloma. SIGNIFICANCE: A super-enhancer screen in t(4;14) multiple myeloma serves to identify genes that promote growth and survival of myeloma cells, which may be evaluated in future studies as therapeutic targets.

Beneficial protective effects of 2-allyl amino 4-methyl sulfanyl butyric acid on glucose metabolism and glycoprotein components in streptozotocin induced diabetic rats with molecular modeling

In the present study, the potential effects of 2-allyl amino 4-methyl sulfanyl butyric acid (AMSB) on the glucose metabolism and glycoprotein components in streptozotocin (STZ) induced experimental diabetic rats were determined. Further, molecular modeling was performed to investigate the modes of AMSB interaction with insulin receptor active sites. The blood glucose and plasma insulin levels were measured in the STZ induced diabetic rats, whereas the glucose metabolism and glycoprotein components were analyzed from the plasma and tissues. After oral treatment of AMSB there was a significant reduction in blood glucose, glucose-6-phosphatase, fructose-1,6-bisphosphatase and glycogen phosphorylase. On the other hand, the activity of the glycoprotein levels, such as hexose, hexosamine, fucose and sialic acid, were significantly reduced. In addition, a significant elevation in plasma insulin, hexokinase, glycogen and glycogen synthase were also observed in the AMSB treated rats. The molecular modeling study revealed that AMSB has a stable binding pattern to the active site of insulin, with a Gscore value of -7.34 Kcal mol^-1. From this study we conclude that AMSB has a potent antidiabetic activity in addition to its protective effect on glycoprotein metabolism.

Superiority of 18F-FDG PET compared to 111In-labelled leucocyte scintigraphy in the evaluation of fever of unknown origin

AIM

To compare the accuracy of positron emission tomography (PET) using (18)F-FDG (Fluorodeoxyglucose) PET with (111)In-labelled leucocytes scintigraphy (LS) in patients with fever of unknown origin (FUO).

METHODS

Twenty-three consecutive patients with FUO were prospectively studied using whole-body LS and PET. Performance of the two modalities for identifying a cause of FUO was evaluated. Final diagnosis was based on biopsy, microbiological tests, clinical and imaging follow-up.

RESULTS

Abnormal tracer uptake was seen in 3/23(13%) and 14/23(61%) patients on LS and PET respectively, suggesting a higher sensitivity (p < 0.01) for the latter. All LS positive cases were identified on PET and confirmed as infection. The causes of FUO in the other PET positive patients were: infection (n = 3), vasculitis (n = 3), non-infectious inflammatory conditions (n = 2) and cancer (n = 1). No specific diagnosis was reached in 2 patients. Of 13 patients without a definite diagnosis following PET and LS, 10 made a spontaneous recovery during the follow-up period and no definite cause for FUO was found on investigation. Still's disease, Polymyalgia rheumatica and Chronic fatigue syndrome/Myalgic encephalomyelitis were diagnosed in the remaining three patients during follow-up. The results thus showed an overall sensitivity of 86% for PET and 20% for LS (p < 0.01). The overall specificity for FDG PET was 78% as against 100% for LS. PET had a PPV of 86% and a NPV of 78% whereas LS had a PPV of 100% and a NPV of 40%.

CONCLUSION

PET has a higher sensitivity than LS in identifying the aetiology of FUO. PET/PET-CT, where available, should be used as the non-invasive investigation of choice in the assessment of patients with FUO.

Selective internal radiation therapy with 90Y-SIR-Spheres microspheres for non-resectable colorectal metastases in the liver

Almost half the patients with colorectal cancer will develop liver metastasis at some stage during their disease. Potentially curative surgical resection is possible in some of these patients. In those patients unsuitable for surgery, treatment with systemic chemotherapy and external radiation therapy is relatively ineffective. Many studies have described the successful use of selective internal radiation therapy (SIRT) with 90Y-SIR-Spheres microspheres in patients with inoperable liver metastasis. The authors report on a patient who has been in complete remission for 1 year after treatment with SIRT.

In vivo treatment with the herbal phenylethanoid acteoside ameliorates intestinal inflammation in dextran sulphate sodium-induced colitis

Recently we demonstrated that in inflammatory bowel disease (IBD) macrophage-oxidative burst activity is increased and NADPH oxidase mRNA is induced. The herbal phenylethanoid acteoside isolated from Plantago lanceolata L. was shown to exhibit anti-oxidative potential. Using the dextran sulphate sodium (DSS)-induced colitis model, in this study we have assessed whether systemic application of acteoside affects colitis. Colitis was induced by DSS in Balb/c mice. Treatment with acteoside (120, 600 microg/mouse/day) was performed intraperitoneally. The colon lengths were determined. Colonic tissue was scored histologically (max. score 8) by a blinded investigator. T cells isolated from mesenteric lymph nodes (MLN) were stimulated with anti-CD3 antibody in the presence of interleukin (IL)-2 (final concentration 10 U/ml). After incubation for 24 h, IL-1beta, IL-6, IL-12 tumour necrosis factor (TNF)-alpha and interferon (IFN)-gamma levels in supernatants were analysed by the beadlyte cytokine detection system. Histological scoring of colonic tissue revealed that application of acteoside was followed by a significantly improved histological score. In acute colitis the histological score was 3.2 with acteoside versus 5.2 with phosphate-buffered saline (PBS) (P < 0.02). In chronic colitis both 120 microg (3.3 versus 5.2) or 600 microg acteoside (3.0 versus 5.2) significantly ameliorated colitis (both P < 0.02). Stimulated MLN from mice with chronic DSS-induced colitis treated with acteoside showed a significant down-regulation of IFN-gamma secretion (195 pg/ml with 600 microg acteoside versus 612 pg/ml with PBS, P < 0.02). Inhibition of oxidative burst activity with acteoside reduced mucosal tissue damage in DSS colitis and could be a therapeutic alternative for IBD treatment. Further studies of this agent are warranted.

A review of the surgical management of metastatic gastrointestinal stromal tumours (GISTs) on imatinib mesylate (Glivec™)

Gastrointestinal stromal tumours (GISTs) are defined as a group of C-KIT positive mesenchymal tumours of the gastrointestinal tract. Although they may arise throughout the gut, the commonest sites are stomach and small intestine. Over 80% of metastases are to the liver and omentum. Targeted therapy (imatinib) can inhibit C-KIT and thereby aberrant tumoural proliferation. Imatinib may induce shrinkage of lesions and cystic change. Such physical changes often correspond with reduced metabolic activity demonstrated by (18-FDG)PET scans. These changes may enable metastatectomy reducing tumour pain and the risk of haemorrhage and rupture in the short term. In the long term, resection may lessen the risk of recurrence by removing potentially resistant clones. The precise role of palliative resection for GIST metastases on imatinib remains unclear. Imatinib has changed the natural history of metastatic GISTs, with increased survival times. Surgery remains an important management strategy in the metastatic setting because complete pathological responses are rare with imatinib. Surgery is likely to provide the best palliation, greatest reduction in tumour burden and eliminate resistant clones. A multidisciplinary team approach with expertise concentrated in a few centres specialising in the management of these rare tumours is vital to the successful outcome. Future issues regarding the management of differential response of the metastases to imatinib are highlighted. With the emergence of techniques enabling identification of the precise mutational status of the C-KIT oncogene, the imatinib/surgery sequence could be tailored to the type of C-KIT mutation.

Oral prednisolone metasulphobenzoate in the treatment of active ulcerative colitis

BACKGROUND

Corticosteroids are one of the mainstays of treatment for active ulcerative colitis, but they are associated with numerous side effects. The sparingly absorbed corticosteroid prednisolone metasulphobenzoate is used topically in the treatment of distal disease. A targeted-release oral preparation (Predocol) has been developed to allow delivery of this drug to the whole colon. We have studied the effect of oral Predocol on inflammation as measured by 99Tc(m)-HMPAO leucocyte scintigraphy in patients with symptomatic and sigmoidoscopic relapse of known extensive ulcerative colitis.

METHODS

Fourteen patients were recruited and received Predocol 47.1 mg twice daily, 8 for 7 days and 6 for 14 days. Scintigraphy was performed prior to and at the end of treatment. Each segment of colon was graded (0-4) and individual scores summed to give a total scintigraphic score.

RESULTS

Total scintigraphic score improved by a mean of 2.5 (P = 0.027). Mean individual scores improved in the rectum by 0.7 (P = 0.038) and in the descending colon by 0.8 (P = 0.033).

CONCLUSIONS

Predocol is an oral preparation of a poorly absorbed salt of prednisolone that is effective in reducing inflammation over short treatment periods in patients with active ulcerative colitis.