The Role of Microbial Translocation and Immune Activation in AIDS-Associated Non-Hodgkin Lymphoma Pathogenesis: What Have We Learned?

Extracellular vesicles as biomarkers for AIDS-associated non-Hodgkin lymphoma risk

Introduction

Extracellular vesicles are membrane-bound structures secreted into the extracellular milieu by cells and can carry bioactive molecules. There is emerging evidence suggesting that EVs play a role in the diagnosis, treatment, and prognosis of certain cancers. In this study, we investigate the association of EVs bearing PD-L1 and molecules important in B-cell activation and differentiation with AIDS-NHL risk.

Methods

EVs were isolated from archived serum collected prior to the diagnosis of AIDS-NHL in cases (N = 51) and matched HIV+ controls (N = 52) who were men enrolled in the Los Angeles site of the MACS/WIHS Combined Cohort Study (MWCCS). Serum specimens of AIDS-NHL cases were collected at a mean time of 1.25 years (range of 2 to 36 months) prior to an AIDS-NHL diagnosis. The expression of PD-L1 and other molecules on EVs (CD40, CD40L, TNF-RII, IL-6Rα, B7-H3, ICAM-1, and FasL) were quantified by Luminex multiplex assay.

Results and discussion

We observed significantly higher levels of EVs bearing PD-L1, CD40, TNF-RII and/or IL-6Rα in AIDS-NHL cases compared with controls. Using multivariate conditional logistic regression models adjusted for age and CD4+ T-cell count, we found that EVs bearing PD-L1 (OR = 1.93; 95% CI: 1.10 - 3.38), CD40 (OR = 1.97, 95% CI: 1.09 - 3.58), TNF-RII (OR = 5.06; 95% CI: 1.99 - 12.85) and/or IL-6Rα (OR = 4.67; 95% CI: 1.40 - 15.53) were significantly and positively associated with AIDS-NHL risk. In addition, EVs bearing these molecules were significantly and positively associated with non-CNS lymphoma: PD-L1 (OR = 1.94; 95% CI: 1.01 - 3.72); CD40 (OR = 2.66; 95% CI: 1.12 - 6.35); TNF-RII (OR = 9.64; 95% CI: 2.52 - 36.86); IL-6Rα (OR = 8.34; 95% CI: 1.73 - 40.15). These findings suggest that EVs bearing PD-L1, CD40, TNF-RII and/or IL-6Rα could serve as biomarkers for the early detection of NHL in PLWH.

HSA Adductomics Reveals Sex Differences in NHL Incidence and Possible Involvement of Microbial Translocation

BACKGROUND

The higher incidence of non-Hodgkin lymphoma (NHL) in males is not well understood. Although reactive oxygen species (ROS) have been implicated as causes of NHL, they cannot be measured directly in archived blood.

METHODS

We performed untargeted adductomics of stable ROS adducts in human serum albumin (HSA) from 67 incident NHL cases and 82 matched controls from the European Prospective Investigation into Cancer and Nutrition-Italy cohort. Regression and classification methods were employed to select features associated with NHL in all subjects and in males and females separately.

RESULTS

Sixty seven HSA-adduct features were quantified by liquid chromatography-high-resolution mass spectrometry at Cys34 (n = 55) and Lys525 (n = 12). Three features were selected for association with NHL in all subjects, while seven were selected for males and five for females with minimal overlap. Two selected features were more abundant in cases and seven in controls, suggesting that altered homeostasis of ROS may affect NHL incidence. Heat maps revealed differential clustering of features between sexes, suggesting differences in operative pathways.

CONCLUSIONS

Adduct clusters dominated by Cys34 oxidation products and disulfides further implicate ROS and redox biology in the etiology of NHL. Sex differences in dietary and alcohol consumption also help to explain the limited overlap of feature selection between sexes. Intriguingly, a disulfide of methanethiol from enteric microbial metabolism was more abundant in male cases, thereby implicating microbial translocation as a potential contributor to NHL in males.

IMPACT

Only two of the ROS adducts associated with NHL overlapped between sexes and one adduct implicates microbial translocation as a risk factor.

Human microbiomes in cancer development and therapy

Colonies formed by bacteria, archaea, fungi, and viral groups and their genomes, metabolites, and expressed proteins constitute complex human microbiomes. An increasing evidences showed that carcinogenesis and disease progression were link to microbiomes. Different organ sources, their microbial species, and their metabolites are different; the mechanisms of carcinogenic or procancerous are also different. Here, we summarize how microbiomes contribute to carcinogenesis and disease progression in cancers of the skin, mouth, esophagus, lung, gastrointestinal, genital, blood, and lymph malignancy. We also insight into the molecular mechanisms of triggering, promoting, or inhibiting carcinogenesis and disease progress induced by microbiomes or/and their secretions of bioactive metabolites. And then, the strategies of application of microorganisms in cancer treatment were discussed in detail. However, the mechanisms by which human microbiomes function are still poorly understood. The bidirectional interactions between microbiotas and endocrine systems need to be clarified. Probiotics and prebiotics are believed to benefit human health via a variety of mechanisms, in particular, in tumor inhibition. It is largely unknown how microbial agents cause cancer or how cancer progresses. We expect this review may open new perspectives on possible therapeutic approaches of patients with cancer.

Lymphoma-Associated Biomarkers Are Increased in Current Smokers in Twin Pairs Discordant for Smoking

Simple Summary

Smoking is associated with a moderate increased risk of Hodgkin and follicular lymphoma. To help understand why, we examined lymphoma-related biomarker levels among 134 smoking and non-smoking twins (67 pairs) ascertained from the Finnish Twin Cohort. We validated self-reported smoking history by measuring serum cotinine, a metabolite of nicotine, from previously collected frozen serum samples. In total, 27 immune biomarkers were assayed using the Luminex Multiplex platform (R & D Systems). We found that four immune response biomarkers were higher and one was lower among smoking compared to non-smoking twins. The strongest association was observed for CCL17/TARC, a biomarker elevated in Hodgkin lymphoma patients. Immune biomarker levels were similar in former smokers and non-smokers. Current smoking may increase levels of immune proteins that could partially explain the association between smoking and risk of certain lymphomas.

Abstract

Smoking is associated with a moderate increased risk of Hodgkin and follicular lymphoma. To understand why, we examined lymphoma-related biomarker levels among 134 smoking and non-smoking twins (67 pairs) ascertained from the Finnish Twin Cohort. Previously collected frozen serum samples were tested for cotinine to validate self-reported smoking history. In total, 27 immune biomarkers were assayed using the Luminex Multiplex platform (R & D Systems). Current and non-current smokers were defined by a serum cotinine concentration of >3.08 ng/mL and ≤3.08 ng/mL, respectively. Associations between biomarkers and smoking were assessed using linear mixed models to estimate beta coefficients and standard errors, adjusting for age, sex and twin pair as a random effect. There were 55 never smokers, 43 current smokers and 36 former smokers. CCL17/TARC, sgp130, haptoglobin, B-cell activating factor (BAFF) and monocyte chemoattractant protein-1 (MCP1) were significantly (p < 0.05) associated with current smoking and correlated with increasing cotinine concentrations (P_trend < 0.05). The strongest association was observed for CCL17/TARC (P_trend = 0.0001). Immune biomarker levels were similar in former and never smokers. Current smoking is associated with increased levels of lymphoma-associated biomarkers, suggesting a possible mechanism for the link between smoking and risk of these two B-cell lymphomas.