Celastrol, which targets IL-2/CD25 binding inhibition, induces T cell-mediated antitumor activity in melanoma.

Interleukin-2 (IL-2) induces contrasting immune responses depending on its binding receptor subunit; thus, selective receptor binding is considered a key challenge in cancer therapeutic strategies. In this study, we aimed to investigate the inhibition of IL-2 action and antitumor activity of celastrol (CEL), a compound identified in a screen for IL-2/CD25 binding inhibitors, and to elucidate the underlying role of CEL in immune cells. We found that CEL selectively impairs the binding of IL-2 and CD25 and directly binds to IL-2 but not to CD25. CEL significantly suppressed the proliferation and signaling of IL-2-dependent murine T cells and interfered with IL-2-responsive STAT5 phosphorylation in IL-2 reporter cells and human PBMCs. After confirming the impact of CEL on IL-2, we evaluated its antitumor activity in C57BL/6 mice bearing B16F10 tumors and found that CEL significantly inhibited tumor growth by increasing CD8+ T cells. We also found that CEL did not inhibit tumor growth in T cell-deficient BALB/c nude mice, suggesting that its activity was mediated by the T-cell response. Moreover, combination therapy with low-dose CEL and a TNFR2 antagonist synergistically improved the therapeutic efficacy of the individual monotherapies by increasing the ratio of intratumoral CD8/Treg cells and suppressing Foxp3 expression. These findings suggest that CEL, which inhibits CD25 binding by targeting IL-2, exerts antitumor activity by mediating the T-cell response and could be a promising candidate for combination therapy in cancer immunotherapy against melanoma.

Chelerythrine, a novel small molecule targeting IL-2, inhibits melanoma progression by blocking the interaction between IL-2 and its receptor.

AIMS: In this study, we investigated the inhibition of IL-2 activity and anticancer efficacy of chelerythrine (CHE), a natural small molecule that targets IL-2 and inhibits CD25 binding, and elucidated the mechanism underlying the action of CHE on immune cells. MAIN METHODS: CHE was discovered by competitive binding ELISA and SPR analysis. The effect of CHE on IL-2 activity was evaluated in CTLL-2, HEK-Blue reporter and immune cells, and in ex vivo generation of regulatory T cells (Treg cells). The antitumor activity of CHE was evaluated in B16F10 tumor-bearing C57BL/6 or BALB/c nude mice. KEY FINDINGS: We identified that CHE, which acts as an IL-2 inhibitor, selectively inhibits the interaction between IL-2 and IL-2Rα and directly binds to IL-2. CHE inhibited the proliferation and signaling of CTLL-2 cells and suppressed IL-2 activity in HEK-Blue reporter and immune cells. CHE prevented the conversion of naive CD4+ T cells into CD4+CD25+Foxp3+ Treg cells in response to IL-2. CHE reduced tumor growth in C57BL/6 mice but not in T-cell-deficient mice, upregulated the expression of IFN-γ and cytotoxic molecules, and limited Foxp3 expression. Furthermore, the combination of CHE and a PD-1 inhibitor synergistically increased antitumor activity in melanoma-bearing mice and almost completely regressed the implanted tumors. SIGNIFICANCE: We found that CHE, which targets IL-2 and inhibits its binding to CD25, exhibits T cell-mediated antitumor activity and that combination therapy with CHE and PD-1 inhibitor induced synergistic antitumor effects, suggesting that CHE may be a promising anticancer agent for melanoma monotherapy and combination therapy.

Combination of LMT-28 and Metformin Improves Beneficial Anti-Inflammatory Effect in Collagen-Induced Arthritis.

OBJECTIVES: The interleukin-6 (IL-6)-mediated signaling pathway plays an essential role in the development of rheumatoid arthritis. LMT-28 suppresses the activation of the IL-6-mediated signaling by direct targeting of gp130. Although LMT-28 and metformin both possess anti-inflammatory activity, the beneficial effect of LMT-28 and metformin combination on a collagen-induced arthritis (CIA) model has not yet been investigated. This study aimed to investigate the anti-inflammatory effect and mechanism of a combination of LMT-28 and metformin in a CIA model. METHODS: In MH7A cells, cell proliferation and the IL-6-mediated signaling pathway following administration of LMT-28 and metformin combination was analyzed through MTT assay and Western blotting. The level of T helper 17 (Th17) cell differentiation from CD4+ T cells was analyzed in mouse splenocytes and human peripheral blood mononuclear cells. Arthritis score, incidence rate, inflammatory cytokine, and T-cell subsets were measured in CIA mice following administration of LMT-28 and metformin combination. RESULTS: Combination treatment with LMT-28 and metformin diminished proliferation of MH7A cells and IL-6-mediated gp130, STAT3, and ERK signaling more than in individual treatments. Furthermore, the differentiation of CD4+ T cells into Th17 cells was attenuated more by combination treatment with LMT-28 and metformin than individual treatments. The combination of LMT-28 and metformin ameliorated the arthritic score better than individual treatments. The combination significantly reduced tumor necrosis factor and IL-6 levels in the sera and had an anti-inflammatory effect on the distribution of Treg/Th17 cells in the lymph nodes. CONCLUSION: Combination treatment with LMT-28 and metformin significantly ameliorates arthritic symptoms in CIA by suppressing Th17 differentiation and IL-6 signaling.

A Comparison of the Anti-Inflammatory Effects of Four Combined Statin and Antiplatelet Therapies on Tumor Necrosis Factor-Mediated Acute Inflammation in vivo.

BACKGROUND: Combination therapy has been administered to patients with chronic or complex diseases due to its improved therapeutic effects compared with the results of monotherapy. Due to the pleiotropic effects of statins and antiplatelets, these drugs have been studied in combination with other drugs, but not all combinations exerted obvious beneficial effects compared with individual drugs. In this study, we aimed to compare the anti-inflammatory effects of 4 different combination therapies of statins and antiplatelets on the tumor necrosis factor (TNF)-mediated inflammation in vivo. METHODS: Mice were orally administered cilostazol plus pravastatin (CILOP) or cilostazol plus rosuvastatin (CILOR), clopidogrel plus pravastatin (CLOP), or clopidogrel plus rosuvastatin (CLOR); then, acute inflammation was induced by the injection of lipopolysaccharide (LPS) or TNF. Serum TNF levels, macrophage accumulation in the lesioned aortas, and mouse mortality were observed to be comparable to the anti-inflammatory effects of the combination therapies. RESULTS: In mice with LPS-induced inflammation, CILOP and CILOR substantially reduced macrophage infiltration of aortic lesions and the serum TNF levels compared with CLOP and CLOR. Moreover, among the 4 combinations, CILOP significantly improved the survival rate of mice with TNF-mediated acute lethal inflammation. CONCLUSIONS: The combination therapy comprising cilostazol and statins, particularly pravastatin, exerted the best anti-TNF effect compared with clopidogrel and statin therapy; thus, a suitable combination therapy, such as CILOP, can be a potential remedy to cure TNF-related diseases.

Beneficial anti-inflammatory effects of combined rosuvastatin and cilostazol in a TNF-driven inflammatory model.

BACKGROUND: Due to anti-inflammatory and anti-thrombotic functions, statins and antiplatelets are widely used for patients with cardiovascular-related or coronary artery diseases. Patients with systemic or complex diseases are commonly prescribed multiple targeted medications; thus, a proper combination of two or more drugs for beneficial efficacy is considered in clinical therapy. Recent studies have suggested that combinational therapy with statins and other medications accelerates their single effect to suppress inflammatory responses. However, the therapeutic efficacy and underlying mechanism of combination treatment with rosuvastatin and cilostazol have been poorly studied. METHODS: Mice were administered rosuvastatin alone, cilostazol alone or rosuvastatin and cilostazol in combination, and then injected with LPS or TNF to induce acute inflammation. The serum TNF level, macrophage infiltration of the lesioned aortas and mice mortality were observed in the acute inflammation model. The phosphorylation of MAPK was analyzed in TNF-stimulated HeLa cells. RESULTS: Compared to the treatment with cilostazol alone, the combination treatment with rosuvastatin and cilostazol significantly reduced not only the levels of TNF in the sera but also macrophage infiltration in aortic lesions. In addition, the combination therapy decreased TNF-mediated phosphorylation of the MAPK signaling pathway and improved the survival rate in the TNF-driven inflammatory mice model. CONCLUSION: Rosuvastatin combined with cilostazol therapy can greatly improve the anti-inflammatory effect of monotherapies, resulting in reduced mortality of mice; thus, we propose the potential of use of this combination therapy as anti-TNF agent.

The key position: influence of staple location on constrained peptide conformation and binding.

Constrained α-helical peptides are showing potential as biological probes and therapeutic agents that target protein-protein interactions. However, the factors that determine the optimal constraint locations are still largely unknown. Using the ß-integrin/talin protein interaction as a model system, we examine the effect of constraint location on helical conformation, as well as binding affinity, using circular dichroism and NMR spectroscopy. Stapling increased the overall helical content of each integrin-based peptide tested. However, NMR analysis revealed that different regions within the peptide are stabilised, depending on constraint location, and that these differences correlate with the changes observed in talin binding mode and affinity. In addition, we show that examination of the atomic structure of the parent peptide provides insight into the appropriate placement of helical constraints.

MicroRNAs differentially expressed in Behçet disease are involved in interleukin-6 production.

BACKGROUND: Behcet's disease (BD) is characterized by systemic recurrent inflammation with increased production of tumor necrosis factor (TNF)-α and interleukin (IL)-6 by peripheral blood mononuclear cells (PBMCs). To gain insight into the underlying mechanisms of this disease, the expression levels of distinct microRNAs in PBMCs of BD patients were determined and their association with TNF-α and IL-6 production was evaluated. FINDINGS: The expression levels of microRNAs, miR-638 and miR-4488, were reduced in patients with stable BD in comparison with healthy controls. In addition, the expression of miR-3591-3p was increased in patients with active BD when compared to patients with stable BD. Transfection of miR-638 and miR-4488 inhibitors, together with miR-3591-3p mimics, increased IL-6 mRNA levels in THP-1 cells in response to LPS stimulation. CONCLUSIONS: We observed differential expression of microRNAs associated with increased production of IL-6 in BD patients.

Relevance of interleukin-10RB to chronic hepatitis B virus infection and biological activities of interferon-λ and interleukin-22.

PURPOSE: The association of a single nucleotide polymorphism of interleukin (IL)-10RB codon 47 with the chronic hepatitis B virus (HBV) infection has been reported in two ethnic populations with different results, but not in a Korean population. IL-10RB is a subunit of receptor complexes for interferon-lambda (IFN-λ) and IL-22, which have antiviral and hepatocyte-protective activity, respectively. This study examined the association of IL-10RB K47E with the outcomes of HBV infection in Korean subjects and the cellular response to these cytokines. METHODS: Genotypes of IL-10RB and the outcomes of HBV infection were analyzed in 1,000 Korean patients. The effect of IFN-λ or IL-22 on HBV replication and cell viability was assessed in hepatoma cells expressing IL-10RB K47 or E47. The transcript level of IL-10RB was examined in Epstein Barr virus-transformed B cells and hepatoma cells. RESULTS: IL-10RB K47E was associated with chronic HBV infection but not with hepatoma in the Korean population. IL-10RB K47E was associated with the transcript level of IL-10RB in transformed B cells but not with the responses in hepatoma cells to IFN-λ or IL-22. HBV replication or 5-fluorouracil-induced cell death was suppressed by treatment of IFN-λ or IL-22 in an IL-10RB K47E-independent manner. CONCLUSIONS: IL-10RB K47E is related to chronic HBV infection in a Korean population, but not to cellular responsiveness to IFN-λ and IL-22.

IFN-lambda endocytosis and IFN-lambda responsive promoter activation are dependent on cholesterol.

Recently, a relationship between receptor endocytosis and downstream signaling has been documented for several immunomodulatory molecules. However, endocytosis of interferon-lambdas (IFN-lambdas) and its impact on IFN-lambda function has not been studied. We show that IFN-lambda is internalized through a cholesterol-dependent, dynamin-independent, and Rho family of GTPase-independent pathway in HepG2 cells. Furthermore, we demonstrate that inhibition of IFN-lambda endocytosis by cholesterol depletion suppresses the activation of IFN-lambda responsive promoters. These results suggest that IFN-lambda endocytosis participates in regulating antiviral gene induction and thus may affect antiviral immunity.

Effect of interferon-lambda on replication of hepatitis B virus in human hepatoma cells.

The antiviral activity of interferon-lambda (IFN-lambda) against several viruses has been reported, but it has not been investigated whether human IFN-lambda can affect replication of the hepatitis B virus (HBV) in human hepatocyte-derived cells. We found that replication of HBV in a human hepatoma cell line was reduced by approximately 30% following treatment with a high concentration of IFN-lambda. Furthermore, we showed that replication of HBV in another human hepatoma cell line was not suppressed by IFN-lambda. However, these cell lines showed a similar level of transcription for the heterodimeric IFN-lambda receptor and the IFN-lambda-induced antiviral proteins. Our results suggest that the antiviral activity of IFN-lambda against HBV may be limited in human cells.