OSdlbcl: An online consensus survival analysis web server based on gene expression profiles of diffuse large B-cell lymphoma

Ubiquitylation of unphosphorylated c-myc by novel E3 ligase SCFFbxl8

Overexpression of c-myc via increased transcription or decreased protein degradation is common to many cancer etiologies. c-myc protein degradation is mediated by ubiquitin-dependent degradation, and this ubiquitylation is regulated by several E3 ligases. The primary regulator is Fbxw7, which binds to a phospho-degron within c-myc. Here, we identify a new E3 ligase for c-myc, Fbxl8 (F-box and Leucine Rich Repeat Protein 8), as an adaptor component of the SCF (Skp1-Cullin1-F-box protein) ubiquitin ligase complex, for selective c-myc degradation. SCFFbxl8 binds and ubiquitylates c-myc, independent of phosphorylation, revealing that it regulates a pool of c-myc distinct from SCFFbxw7. Loss of Fbxl8 increases c-myc protein levels, protein stability, and cell division, while overexpression of Fbxl8 reduces c-myc protein levels. Concurrent loss of Fbxl8 and Fbxw7 triggers a robust increase in c-myc protein levels consistent with targeting distinct pools of c-myc. This work highlights new mechanisms regulating c-myc degradation.

The dual role of CD70 in B-cell lymphomagenesis

BACKGROUND

CD70 is a costimulatory molecule that is transiently expressed on a small set of activated lymphocytes and is involved in T-cell-mediated immunity. However, the role of CD70 in B-cell malignancies remains controversial.

METHODS

We investigated the clinical relevance of CD70 genetic alterations and its protein expression in two diffuse large B-cell lymphoma (DLBCL) cohorts with different ethnic backgrounds. We also performed transcriptomic analysis to explore the role of CD70 alterations in tumour microenvironment. We further tested the blockade of CD70 in combination with PD-L1 inhibitor in a murine lymphoma model.

RESULTS

We showed that CD70 genetic aberrations occurred more frequently in the Chinese DLBCL cohort (56/233, 24.0%) than in the Swedish cohort (9/84, 10.8%), especially in those with concomitant hepatitis B virus (HBV) infection. The CD70 genetic changes in DLBCL resulted in a reduction/loss of protein expression and/or CD27 binding, which might impair T cell priming and were independently associated with poor overall survival. Paradoxically, we observed that over-expression of CD70 protein was also associated with a poor treatment response, as well as an advanced disease stage and EBV infection. More exhausted CD8+ T cells were furthermore identified in CD70 high-expression DLBCLs. Finally, in a murine lymphoma model, we demonstrated that blocking the CD70/CD27 and/or PD1/PD-L1 interactions could reduce CD70+ lymphoma growth in vivo, by directly impairing the tumour cell proliferation and rescuing the exhausted T cells.

CONCLUSIONS

Our findings suggest that CD70 can play a role in either tumour suppression or oncogenesis in DLBCL, likely via distinct immune evasion mechanisms, that is, impairing T cell priming or inducing T cell exhaustion. Characterisation of specific dysfunction of CD70 in DLBCL may thus provide opportunities for the development of novel targeted immuno-therapeutic strategies.

High APLN Expression Predicts Poor Prognosis for Glioma Patients

Apelin (APLN) is an endogenous ligand of the G protein-coupled receptor APJ (APLNR). APLN/APLNR system was involved in a variety of pathological and physiological functions, such as tumorigenesis and development. However, its prognostic roles in patients with central nervous system (CNS) cancers remain unknown. The present study was designed to explore the expression profile, prognostic significance, and interaction network of APLN/APLNR by integrating data from Oncomine, GEPIA, LOGpc, STRING, GeneMANIA, and immunohistochemical staining. The results demonstrated that APLN and APLNR mRNA expression were significantly increased in CNS cancers, including both low-grade glioma (LGG) and glioblastoma (GBM), when compared with normal CNS tissues. The high APLN, but not APLNR, expression was significantly correlated with overall survival (OS), recurrence free survival (RFS), and progression free survival (PFS) of LGG patients. However, neither APLN nor APLNR expression was significantly related to prognostic value in terms of OS, disease free interval (DFI), disease specific survival (DSS), or progression free interval (PFI) for GBM patients. Additionally, immunohistochemistry staining confirmed the increased APLN expression in tissues of LGG patients with grade II than grade I. These results showed that an elevated APLN level could predict poor OS, RFS, and PFS for LGG patients, and it could be a promising prognostic biomarker for LGG.

Expression of L-type amino acid transporter 1 is a poor prognostic factor for Non-Hodgkin's lymphoma

L-type neutral amino acid transporter 1 (LAT1) is a heterodimeric membrane transport protein involved in neutral amino acid transport. LAT1 is highly expressed in various malignant solid tumors and plays an essential role in cell proliferation. However, its role in malignant lymphoma remains unknown. Here, we evaluated LAT1 expression level in tissues from 138 patients with Non-Hodgkin lymphoma (NHL). Overexpression of LAT1 was confirmed in all types of NHL and we found that there is a significant correlation between the level of LAT1 expression and lymphoma grade. The LAT1 expression was higher in aggressive types of lymphomas when compared with static types of lymphomas, suggesting that active tumor proliferation requires nutrient uptake via LAT1. The expression level of LAT1 was inversely correlated with patients’ survival span. Furthermore, pharmacological inhibition of LAT1 by a specific inhibitor JPH203 inhibits lymphoma cell growth. In conclusion, our study demonstrated that LAT1 expression can be used as a prognostic marker for patients with NHL and targeting LAT1 by JPH203 can be a novel therapeutic modality for NHL.

Fbxl8 suppresses lymphoma growth and hematopoietic transformation through degradation of cyclin D3

Overexpression of D-type cyclins in human cancer frequently occurs as a result of protein stabilization, emphasizing the importance of identification of the machinery that regulates their ubiqutin-dependent degradation. Cyclin D3 is overexpressed in ~50% of Burkitt’s lymphoma correlating with a mutation of Thr-283. However, the E3 ligase that regulates phosphorylated cyclin D3 and whether a stabilized, phosphorylation deficient mutant of cyclin D3, has oncogenic activity are undefined. We describe the identification of SCF-Fbxl8 as the E3 ligase for Thr-283 phosphorylated cyclin D3. SCF-Fbxl8 poly-ubiquitylates p-Thr-283 cyclin D3 targeting it to the proteasome. Functional investigation demonstrates that Fbxl8 antagonizes cell cycle progression, hematopoietic cell proliferation, and oncogene-induced transformation through degradation of cyclin D3, which is abolished by expression of cyclin D3T283A, a non-phosphorylatable mutant. Clinically, the expression of cyclin D3 is inversely correlated with the expression of Fbxl8 in lymphomas from human patients implicating Fbxl8 functions as a tumor suppressor.

Fbxl8 suppresses cell division, cell proliferation, and tumorigenesis through phosphorylation-dependent degradation of cyclin D3.

Fbxl8 suppresses oncogene-induced transformation of hematopoietic cells and lymphoma cell proliferation through cyclin D3 degradation.

OSluca: An Interactive Web Server to Evaluate Prognostic Biomarkers for Lung Cancer

Lung cancer is the principal cause of leading cancer-related incidence and mortality in the world. Various studies have excavated the potential prognostic biomarkers for cancer patients based on gene expression profiles. However, most of these reported biomarkers lack independent validation in multiple cohorts. Herein, we collected 35 datasets with long-term follow-up clinical information from TCGA (2 cohorts), GEO (32 cohorts), and Roepman study (1 cohort), and developed a web server named OSluca (Online consensus Survival for Lung Cancer) to assess the prognostic value of genes in lung cancer. The input of OSluca is an official gene symbol, and the output web page of OSluca displays the survival analysis summary with a forest plot and a survival table from Cox proportional regression in each cohort and combined cohorts. To test the performance of OSluca, 104 previously reported prognostic biomarkers in lung carcinoma were evaluated in OSluca. In conclusion, OSluca is a highly valuable and interactive prognostic web server for lung cancer. It can be accessed at http:// bioinfo.henu.edu.cn/LUCA/LUCAList.jsp.

OSdlbcl: An online consensus survival analysis web server based on gene expression profiles of diffuse large B-cell lymphoma

Diffuse large B‐cell lymphoma (DLBCL) is the most common subtype of non‐Hodgkin lymphoma (NHL) and is a clinical, pathological, and molecular heterogeneous disease with highly variable clinical outcomes. Currently, valid prognostic biomarkers in DLBCL are still lacking. To optimize targeted therapy and improve the prognosis of DLBCL, the performance of proposed biomarkers needs to be evaluated in multiple cohorts, and new biomarkers need to be investigated in large datasets. Here, we developed a consensus Online Survival analysis web server for Diffuse Large B‐Cell Lymphoma, abbreviated OSdlbcl, to assess the prognostic value of individual gene. To build OSdlbcl, we collected 1100 samples with gene expression profiles and clinical follow‐up information from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases. In addition, DNA mutation data were also collected from the TCGA database. Overall survival (OS), progression‐free survival (PFS), disease‐specific survival (DSS), disease‐free interval (DFI), and progression‐free interval (PFI) are important endpoints to reflect the survival rate in OSdlbcl. Moreover, clinical features were integrated into OSdlbcl to allow data stratifications according to the user's special needs. By inputting an official gene symbol and selecting desired criteria, the survival analysis results can be graphically presented by the Kaplan‐Meier (KM) plot with hazard ratio (HR) and log‐rank p value. As a proof‐of‐concept demonstration, the prognostic value of 23 previously reported survival associated biomarkers, such as transcription factors FOXP1 and BCL2, was evaluated in OSdlbcl and found to be significantly associated with survival as reported (HR = 1.73, P < .01; HR = 1.47, P = .03, respectively). In conclusion, OSdlbcl is a new web server that integrates public gene expression, gene mutation data, and clinical follow‐up information to provide prognosis evaluations for biomarker development for DLBCL. The OSdlbcl web server is available at https://bioinfo.henu.edu.cn/DLBCL/DLBCLList.jsp.