CCL3 Signaling in the Tumor Microenvironment

Within the tumor microenvironment, chemokines play a key role in immune cell trafficking regulation and immune landscape formulation. CCL3 or macrophage inflammatory protein-1α (MIP-1α), an important chemokine implicated in both immune surveillance and tolerance, has emerged as a prognostic biomarker in both solid and hematological malignancies. CCL3 exerts both antitumor and pro-tumor behavior which is context dependent highlighting the complexity of the underlying interrelated signaling cascades. Current CCL3-directed therapeutic approaches are investigational and further optimization is required to increase efficacy and minimize adverse events.

Soluble PD-1 ligands regulate T-cell function in Waldenstrom macroglobulinemia

Although immune checkpoint molecules regulate the progression of certain cancers, their significance in malignant development of Waldenstrom macroglobulinemia (WM), an incurable low-grade B-cell lymphoma, remains unknown. Recently, cytokines in the bone marrow (BM) microenvironment are shown to contribute to the pathobiology of WM. Here, we investigated the impact of cytokines, including interleukin-6 (IL-6) and IL-21, on immune regulation and particularly on the programmed death-1 (PD-1) and its ligands PD-L1 and PD-L2. We showed that IL-21, interferon γ, and IL-6 significantly induced PD-L1 and PD-L2 gene expression in WM cell lines. Increased PD-L1 and PD-L2 messenger RNA was also detected in patients' BM cells. Patients' nonmalignant BM cells, including T cells and monocytes, showed increased PD-L1, but minimal or undetectable PD-L2 surface expression. There was also very modest PD-L1 and PD-L2 surface expression by malignant WM cells, suggesting that ligands are cleaved from the cell surface. Levels of soluble ligands were higher in patients' BM plasma and blood serum than controls. Furthermore, IL-21 and IL-6 increased secreted PD-L1 in the culture media of WM cell lines, implying that elevated levels of soluble PD-1 ligands are cytokine mediated. Soluble PD-1 ligands reduced T-cell proliferation, phosphorylated extracellular signal-regulated kinase and cyclin A levels, mitochondrial adenosine triphosphate production, and spare respiratory capacity. In conclusion, we identify that soluble PD-1 ligands are elevated in WM patients and, in addition to surface-bound ligands in WM BM, could regulate T-cell function. Given the capability of secreted forms to be bioactive at distant sites, soluble PD-1 ligands have the potential to promote disease progression in WM.

Elevated vWF Antigen Serum Levels Are Associated With Poor Prognosis, and Decreased Circulating ADAMTS-13 Antigen Levels Are Associated With Increased IgM Levels and Features of WM but not Increased vWF Levels in Patients With Symptomatic WM

BACKGROUND

Waldenström's macroglobulinemia (WM) is a rare malignancy characterized by bone marrow infiltration by lymphoplasmacytic cells and the presence of a monoclonal IgM paraprotein. The interactions of lymphoplasmacytic cells with other cells in their microenvironment, including mast cells and endothelial cells, support their survival and proliferation and can induce resistance to therapy. von Willebrand factor (vWF) plays a key role in primary hemostasis but is also a marker of endothelial "stimulation." High levels of vWF have been associated with an adverse prognosis in patients with symptomatic WM and might reflect the interactions between lymphoplasmacytic cells and other cells of their microenvironment.

MATERIALS AND METHODS

Considering vWF and ADAMTS-13 (a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13) as markers of endothelial dysfunction and activation, we evaluated the prognostic importance of vWF and ADAMTS-13 antigen levels in the serum of patients with previously untreated symptomatic WM to validate vWF as a possible prognostic marker for progression-free and overall survival. We also validated the measurement of vWF in the serum instead of citrated plasma and investigated the possible correlations of ADAMTS-13 antigen levels with disease characteristics. The analysis included 42 patients with symptomatic WM and 19 matched healthy controls.

RESULTS

The serum levels of vWF antigen provided significant prognostic information, and patients with levels ≥ 200 IU/dL had a very poor prognosis compared with patients with lower levels. The ADAMTS-13 antigen levels were decreased in WM patients and correlated with the IgM levels, β₂-microglobulin, and extent of bone marrow infiltration.

CONCLUSION

vWF levels measured in the serum could become an important prognostic marker in patients with WM and requires further investigation.

The association of CCL3 and CCL4 polymorphisms with HCV clearance in Chinese Han population

AIM

To explore the association of CCL3 (rs1063340) and CCL4 (rs1049807) polymorphisms with hepatitis C virus (HCV) clearance and sustained virologic response (SVR).

METHODS

Two populations were enrolled in the current study; one was a general population including 1585 untreated individuals, with HCV infection and the other was a treatment population comprising 353 HCV-infected patients treated with pegylated interferon-α and ribavirin (pegIFN-α/RBV). Two single nucleotide polymorphisms (SNPs) were genotyped, and the relationship between HCV clearance and treatment outcome was analysed.

RESULTS

The general population comprised 995 persistent HCV cases (both HCV RNA and anti-HCV were positive) and 590 spontaneous clearance cases (HCV RNA was negative, but anti-HCV was positive). An association between the SNPs and HCV clearance was not found in our study. The treatment population consisted of 235 patients who achieved SVR and 118 non-responders. Variants of both SNPs (rs1063340-C and rs1049807-G) were associated with a reduction in SVR following IFN treatment (dominant model: P = 0.026 for rs1063340 and P = 0.048 for rs1049807). In addition, the ancestral alleles of rs1063340 and rs1049807 increased the likelihood of virus clearance by 62% compared to both the derived and minor alleles of the two SNPs (P = 0.040).The interaction analysis showed that the level of glucose interacted with the association of rs1063340 and SVR.

CONCLUSIONS

Our results suggested that genetic variants at the CCL3 and CCL4 loci may be marker SNPs for risk of HCV treatment outcome.

Macrophage inflammatory protein 1 alpha (MIP-1α) may be associated with poor outcome in patients with extranodal NK/T-cell lymphoma

The macrophage inflammatory protein 1α (MIP-1α) is anticipated to have a role in extranodal natural killer (NK)/T-cell lymphoma (ENKTL) because the expression of MIP-1α is related to Epstein-Barr virus (EBV) latency in EBV-related non-Hodgkin lymphoma cells. Thus, we measured the serum level of MIP-1α in 69 patients with ENKTL using frozen serum samples that were archived at diagnosis. As serum level of MIP-1α was not detectable in 19 patients (range: 0-24.37 pg/mL), patients were dichotomized into positive (n = 50) and negative (n = 19) MIP-1α groups according to the presence of detectable level of MIP-1α in serum. MIP-1α-positive group showed a significantly poor overall survival (OS) in comparison with the MIP-1α-negative group (p = 0.004). In the subgroup analysis, the positivity of MIP-1α was significantly associated with OS in patients with stage IIIE/IV and a detectable level of EBV DNA (p = 0.002 and 0.032, respectively). Multivariate analysis also showed that the positivity of MIP-1α was independently associated with worse OS together with bone marrow involvement (p = 0.002). An in vitro study with patient-derived ENKTL tumour cells showed the expression of CCR1 and CCR5 on the surface of tumour cells (28% and 14%, respectively) , and the addition of MIP-1α to the culture media of tumour cells increased cell growth supporting the negative impact of MIP-1α on the prognosis of ENKTL patients. In conclusion, serum levels of MIP-1α could predict survival outcomes in patients with ENKTL. Therefore, MIP-1α should be considered for prognostication and a potential therapeutic target. Copyright © 2016 John Wiley & Sons, Ltd.