Indicator Of Diffuse Large B-cell Lymphoma Research Articles

KIAA1429 REGULATES HIPPO‐YAP PATHWAY TO MAINTAIN THE TUMORIGENICITY OF DIFFUSE LARGE B‐CELL LYMPHOMA VIA AN M6A‐DEPENDENT MANNER

Introduction: N6-methyladenosine (m6A) is the most abundant form of chemical modification in eukaryotes. m6A methylation is dynamically modulated by diverse types of regulators, including methyltransferases (‘writers’), RNA binding proteins (‘readers’), and demethylases (‘erasers’). Growing evidence has shown that m6A methylation plays an essential role in the development and progression of multiple cancers. However, the functions of m6A methyltransferase KIAA1429 in diffuse large B-cell lymphoma (DLBCL) remain undefined. Here, we aimed to unravel an epitranscriptomic mechanism mediated by the m6A methyltransferase KIAA1429 in DLBCL. Methods: Collecting lymph node biopsy samples from 60 de novo DLBCL patients and 20 reactive hyperplasia cases after informed consent. The biological function of KIAA1429 was evaluated using CRISPR/Cas9 mediated genomic deletion and CRISPR/dCas9-VP64 activation. RNA-seq, MeRIP-seq, RIP assays, luciferase activity assay, RNA stability experiments, and co-immunoprecipitation were performed to explore the regulatory mechanism of KIAA1429 in DLBCL. DLBCL cells were subcutaneously injected into SCID-Beige mice to establish xenograft models. The Institutional Animal Care guidelines were followed during the animal experiments. Results: m6A regulators were dysregulated in DLBCL, and a predictive model based on m6A score was developed. KIAA1429 expression was found to be elevated and associated with poor prognosis. KIAA1429 knockout inhibited DLBCL cell proliferation, induced cell cycle arrest in the G2/M phase, promoted apoptosis in vitro, and repressed tumor growth in vivo. Furthermore, KIAA1429 mediated m6A modification of CHST11 mRNA and recruited YTHDF2 to reduce the stability and expression of CHST11. By decreasing MOB1B expression, CHST11 inhibited Hippo-YAP signaling, reprogramming the expression of Hippo target genes (Figure 1). Conclusions: In summary, we identified for the first time that m6A methylation regulators were dysregulated, and its risk score could exert as an independent prognostic indicator in DLBCL. More importantly, our study identified a novel mechanism in which KIAA1429/YTHDF2-coupled epitranscriptional repression of CHST11 inactivates the Hippo-YAP pathway in DLBCL, highlighting the potential of KIAA1429 as a novel predictive biomarker and therapeutic target for DLBCL progression. Keywords: aggressive B-cell non-Hodgkin lymphoma, bioinformatics, computational and systems biology, genomics, epigenomics, and other -omics No conflicts of interests pertinent to the abstract.

The prognostic significance of whole-body and spleen MTV (metabolic tumor volume) scanning for patients with diffuse large B cell lymphoma

Positron Emission Tomography-Computed Tomography (PET-CT) has been changing diagnostic and therapeutic strategies for patients with cancers, and several PET-CT-related prognostic factors have been reported. We have focused on metabolic tumor volumes (MTVs) over the whole body and in specific organs using 18F-PET-CT imaging, and have compared clinical data to know the prognosis of patients with diffuse large B cell lymphoma (DLBCL). From January 2006 to December 2016, patients who were newly diagnosed for de novo DLBCL and who received 18F-FDG PET-CT scans for disease staging at Ehime University Hospital were reviewed. A total of forty out of 108 patients with DLBCL were analyzed. The median and the average follow-up were 3.9years and 3.6years. Both MTV50 and MTV60 whole-body searching indicated effective prognostic values for patients with DLBCL statistically (P = 0.027). However, analysis of MTVs in the spleen and in bone marrow did not provide any prognostic value. Receiver operating characteristic (ROC) analysis indicated that the cutoff level 25.8 in MTV60 is the most effective prognostic value (P = 0.022) which predicts patient survival after treatment with R-CHOP chemotherapy. MTV60 using whole-body scanning appears to be an effective indicator in DLBCL and indicates the patient prognosis.

Intralymphatic Spread is a Rare Finding Associated With Poor Prognosis in Diffuse Large B-Cell Lymphoma With Extranodal Involvements.

Intralymphatic spread is common in solid cancers, but has been rarely studied in lymphomas. Review of 635 extranodal specimens from 475 diffuse large B-cell lymphoma (DLBCL) patients revealed intralymphatic spread in 10 surgical resection specimens from 10 patients including 9 de novo DLBCLs and 1 Richter transformation. The prevalence in de novo DLBCL with extranodal involvements was 1.65%. The most common involved site of intralymphatic spread was the gastrointestinal tract, followed by the female genital tract and breasts. Lymphatic vessels, lined by D2-40-positive endothelial cells, were expanded by lymphoma cells, reminiscent of intravascular lymphoma or tumor emboli. None of the involved lymphatic vessels were located in the mucosa. Patients with intralymphatic spread had a trend of lower overall response rate and a trend of higher progressive disease than those without intralymphatic spread. Compared with patients without intralymphatic spread, those patients with intralymphatic spread had a shorter median overall survival (14.3 vs. 96.2 mo; P=0.004) and a shorter median progression-free survival (11.2 vs. 64.2 mo; P=0.01), respectively. Multivariate analyses showed that intralymphatic spread was an independent poor prognostic factor for overall survival (hazard ratio, 3.029; 95% confidence interval, 1.315-6.978; P=0.009), irrespective of the National Comprehensive Cancer Network-International Prognostic Index, B symptoms, and serum albumin levels. Among patients who underwent surgical resection, intralymphatic spread was still an independent prognostic factor. In conclusion, our study demonstrated extranodal intralymphatic spread in DLBCL. Inspiringly, this rare morphologic finding may serve as a new negative prognostic indicator in DLBCL with extranodal involvements.

Role of the abnormal HIF‐1α‐glycolysis‐aerobic oxidation pathway in non‐Hodgkin lymphoma and the intervention study

Introduction: Diffuse large B-cell lymphoma is a highly heterogeneous entity with varied clinical manifestation and prognosis. Although the immunochemotherapy improves treatment responses, approximately 40% of the patients still eventually endure refractory/relapsed diseases. So how can we identify patients who are unlikely to be cured with conventional therapy and thus to optimize the strategy have become extremely meaningful. The metabolic reprogramming is a remarkably distinct character of tumor cells and is linked to proliferation, drug resistance, survival advantages, and tumor progression. Malignant tumor cells prefer glycolysis rather than aerobic oxidation even under aerobic surroundings. Furthermore, this altered metabolism is an active adjustment regulated by hypoxia inducible factor 1α (HIF-1α) in a reversible manner. The aim of this study is to clarify the role of the balance between glycolysis and aerobic oxidation in DLBCL and to explore the potential of targeting abnormal metabolic phenotype for NHL. Methods: Expressions of HIF-1α, key enzymes of glycolysis pathway hexokinase II (HKII), and aerobic oxidation pathway succinate dehydrogenase (SDHA) in lymphoma samples from DLBCL patients were detected by immunohistochemistry, and the association between expression levels and clinical outcomes were analyzed. SU-DHL-4 cells and Raji cells were stably transfected with lentiviral vectors carried with short hairpin RNA targeting either HIF-1α gene or HKII gene and control vectors encoding a nonmammalian shRNA. Results: Retrospective analysis of the 83 newly diagnosed DLBCL patients showed that HIF-1α+, HKIIhigh and SDHAlow were significantly correlated with inferior PFS and OS. A small subset of patients was identified that the H-H-S group (HIF-1α+HKIIhighSDHAlow), representing that critical regulator and enzymes of glycolysis-aerobic oxidation pathway are all abnormaly expressed, had significantly inferior PFS (3-year PFS, 14.3% vs 78.3%, P = .001) and OS (3-year OS, 14.3% vs 89.9%, P < .001) compared to the non–H-H-S group. Prognostic factors such as LDH, Ki67, SUVmax, IPI, and non-GCB subtype significantly differed between H-H-S group and non–H-H-S group. Furthermore, H-H-S group was demonstrated as an independent prognostic factor. HKII gene silencing significantly suppressed proliferation and abnormal glycolytic metabolism of lymphoma cells as well as enhanced cell apoptosis and sensitivity to chemotherapeutic drugs. Same phenomena were found while HIF-1α was interfered by specific shRNA. Conclusions: The abnormal HIF-1α-glycolysis-aerobic oxidation pathway might act as a prognostic indicator in DLBCL. Knocking down either HIF-1α gene or HKII gene could rescue malignant biological phenotypes of lymphoma cells, suggesting that targeting malignant metabolic phenotype may be a promising approach for refractory/relapsed lymphoma. Keywords: diffuse large B-cell lymphoma (DLBCL); prognostic indices; R-CHOP

Expression and Clinical Significance of CD68+ Lymphoma Associated Macrophage in Diffuse Large B-Cell Lymphoma

Objective To investigate the expression and clinical significance of CD68+ lymphoma associated macrophage (LAM) in diffuse large B-cell lymphoma (DLBCL).Methods From October 2011 to April 2013,a total of 60 cases with DLBCL who were first diagnosed in the First Affiliated Hospital of Nanchang University were collected into this study,as the study group.And 20 cased with lymph node reactive hyperplasia who were first diagnosed in the same hospital during the same period were included into the control group.The number of CD68+ LAM of study group and control group was detected by two-step immunohistochemical staining method,and compared the number of CD68+ LAM among DLBCL patients with different clinical features.The study protocol was approved by the Ethical Review Board of Investigation in Human Being of the First Affiliated Hospital of Nanchang University.Informed consent was obtained from all participants.There were no significant differences of patients' general clinical features between two groups (P＞ 0.05).Results The number of CD68+ LAM among DLBCL patients with different ages,different Ann Arbor stage,with and without spinal cord invasion was different from each other and the differences were all statistically significant (F=2.946,3.798,2.214; P=0.024,0.009,0.043).While there were no statistically significant differences among DLBCL patients with different ages,different serum lactic dehydrogenase levels,with or without B symptom and with or without megalo-lump (P＞0.05).The number of CD68+ LAM in DLBCL patients with different international prognostic index (IPI) scores compared with that in control group,the difference was statistically significant (F=26.522,P＜0.05); And the number of CD68+ LAM in each IPI level group was higher than control group (P＜0.05).Among the 60 cases with DLBCL,there were 13 cases (21.7％) with high-density expression of CD68+ LAM and 47 cases (78.3％) with low-density expression.The therapy efficiency of CD68+ LAM high-density expression group (10/13,76.9 ％) was lower than the low-density expression group (44/47,93.6％),and the difference was statistically significant (Ridit z =12.152,P＜0.05).The median survival time of CD68+ LAM high-density expression group was 22.1 months,while the low-density expression group was 40.1 months,the difference was statistically significant (P ＜ 0.05).Conclusions The expression of CD68+ LAM in DLBCL patients with different malignant degree and prognosis risk differ from each other.And prognosis of DLBCL patients with different expression of CD68+ LAM also differs from each other.Clinical practice may try to use CD68+ LAM as a prognostic indicator of DLBCL. Key words: Lymphoma,large B-cell,diffuse; Macrophages; Lymphoma,non-Hodgkin

Non-immunoglobulin/ BCL6 Gene Fusion in Diffuse Large B-cell Lymphoma: Prognostic Implications

3q27 translocation affecting the BCL6 gene is one of the most common chromosomal abnormalities in diffuse large B-cell lymphoma (DLBCL). BCL6 translocation can involve not only one of the three immunoglobulin gene (Ig ) loci but also another non- Ig chromosomal locus. 5'-rapid amplification of cDNA ends and long-distance inverse polymerase chain reaction (PCR) methods have identified a total of 13 recurrent non- Ig partner genes to date. As the result of non- Ig / BCL6 translocation, many types of regulatory sequences of each partner gene substitute for the 5' untranslated region of the BCL6 and the rearranged BCL6 is presumed to be under the control of the replaced promoter activity. BCL6 translocation occurs more frequently in extranodal DLBCL than in node-based disease. However, the impact of BCL6 translocation on the treatment outcome of DLBCL has been the subject of controversy. We found that survival of DLBCL patients with non- Ig partners was inferior to that of those with Ig / BCL6 translocation, suggesting that non- Ig / BCL6 fusion is a poor prognostic indicator of DLBCL. We next created BCL6 expression plasmids containing a series of non- Ig / BCL6 fusion genes. COS-7 cells transiently transfected with these plasmids expressed high levels of Bcl-6 protein and showed characteristic punctate nuclear staining. These findings suggested that non- Ig / BCL6 translocation plays a pathogenetic role in a proportion of DLBCL.

Nonimmunoglobulin (non-Ig)/BCL6gene fusion in diffuse large B-cell lymphoma results in worse prognosis than Ig/BCL6

Chromosomal translocation involving the BCL6 gene affects not only immunoglobulin (Ig) genes but also a number of non-Ig genes as partners. The molecular anatomy of the BCL6 gene rearrangements in 39 cases with diffuse large B-cell lymphoma (DLBCL) by long-distance polymerase chain reaction–based assays was determined. The results showed that Iggenes were affected in 21 cases; non-Ig genes, 15 cases; a deletion of more than a 1-kb segment, 2 cases; and a point mutation, 1 case. Comparative studies between the 21 cases withIg gene partners and the 17 cases with non-Iggene partners, including 2 cases with the deletion, showed that the overall survival of the latter group of patients was significantly inferior to that of the former (P = .0440), and the estimated 2-year overall survival rates were 58.3% vs 17.6% (P = .005). Non-Ig/BCL6 fusion is a poor prognostic indicator of DLBCL, and DLBCL with BCL6translocation could be subclassified according to the individual partner locus and/or gene.