Inhibition of Glutathione and Thioredoxin Metabolism Enhances Sensitivity to Perifosine in Head and Neck Cancer Cells

The hypothesis that the Akt inhibitor, perifosine (PER), combined with inhibitors of glutathione (GSH) and thioredoxin (Trx) metabolism will induce cytotoxicity via metabolic oxidative stress in human head and neck cancer (HNSCC) cells was tested. PER induced increases in glutathione disulfide (%GSSG) in FaDu, Cal-27, and SCC-25 HNSCCs as well as causing significant clonogenic cell killing in FaDu and Cal-27, which was suppressed by simultaneous treatment with N-acetylcysteine (NAC). An inhibitor of GSH synthesis, buthionine sulfoximine (BSO), sensitized Cal-27 and SCC-25 cells to PER-induced clonogenic killing as well as decreased total GSH and increased %GSSG. Additionally, inhibition of thioredoxin reductase activity (TrxRed) with auranofin (AUR) was able to induce PER sensitization in SCC-25 cells that were initially refractory to PER. These results support the conclusion that PER induces oxidative stress and clonogenic killing in HNSCC cells that is enhanced with inhibitors of GSH and Trx metabolism

A preliminary analysis of interleukin-1 ligands as potential predictive biomarkers of response to cetuximab

The epidermal growth factor receptor (EGFR) monoclonal IgG1 antibody cetuximab is approved for first-line treatment of recurrent and metastatic (R/M) HNSCC as a part of the standard of care EXTREME regimen (platinum/5-fluorouracil/cetuximab). This regimen has relatively high response and disease control rates but is generally not curative and many patients will experience recurrent disease and/or metastasis. Therefore, there is a great need to identify predictive biomarkers for recurrence and disease progression in cetuximab-treated HNSCC patients to facilitate patient management and allow for treatment modification. The goal of this work is to assess the potential of activating interleukin-1 (IL-1) ligands (IL-1 alpha [IL-1α], IL-1 beta [IL-1β]) as predictive biomarkers of survival outcomes in HNSCC patients treated with cetuximab-based chemotherapy.2016 AACR-Bayer Innovation and Discovery Grant [16-80-44-SIMO]; National Institutes of Health (NIH) [R01DE024550, F99CA223062, R01 CA177669, P30 CA006973, P50 DE019032, T32 AI007511]; University of Iowa Department of Pathology Research Grant; University of Iowa Head and Neck Cancer Symposium Seed Grant; Johns Hopkins University Catalyst AwardOpen access journalThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

In situ immunization of a TLR9 agonist virus-like particle enhances anti-PD1 therapy

Background CMP-001 is a novel Toll-like receptor-9 agonist that consists of an unmethylated CpG-A motif-rich G10 oligodeoxynucleotide (ODN) encapsulated in virus-like particles. In situ vaccination of CMP-001 is believed to activate local tumor-associated plasmacytoid dendritic cells (pDCs) leading to type I interferon secretion and tumor antigen presentation to T cells and systemic antitumor T cell responses. This study is designed to investigate if CMP-001 would enhance head and neck squamous cell carcinoma (HNSCC) tumor response to anti-programmed cell death protein-1 (anti-PD-1) therapy in a human papilloma virus-positive (HPV+) tumor mouse model.Methods Immune cell activation in response to CMP-001±anti-Qβ was performed using co-cultures of peripheral blood mononuclear cells and HPV+/HPV- HNSCC cells and then analyzed by flow cytometry. In situ vaccination with CMP-001 alone and in combination with anti-PD-1 was investigated in C57BL/6 mice-bearing mEERL HNSCC tumors and analyzed for anti-Qβ development, antitumor response, survival and immune cell recruitment. The role of antitumor immune response due to CMP-001+anti-PD-1 treatment was investigated by the depletion of natural killer (NK), CD4+ T, and CD8+ T cells.Results Results showed that the activity of CMP-001 on immune cell (pDCs, monocytes, CD4+/CD8+ T cells and NK cells) activation depends on the presence of anti-Qβ. A 2-week ‘priming’ period after subcutaneous administration of CMP-001 was required for robust anti-Qβ development in mice. In situ vaccination of CMP-001 was superior to unencapsulated G10 CpG-A ODN at suppressing both injected and uninjected (distant) tumors. In situ vaccination of CMP-001 in combination with anti-PD-1 therapy induced durable tumor regression at injected and distant tumors and significantly prolonged mouse survival compared with anti-PD-1 therapy alone. The antitumor effect of CMP-001+anti-PD-1 was accompanied by increased interferon gamma (IFNγ)+ CD4+/CD8+ T cells compared with control-treated mice. The therapeutic and abscopal effect of CMP-001+ anti-PD-1 therapy was completely abrogated by CD8+ T cell depletion.Conclusions These results demonstrate that in situ vaccination with CMP-001 can induce both local and abscopal antitumor immune responses. Additionally, the antitumor efficacy of CMP-001 combined with α-PD-1 therapy warrants further study as a novel immunotherapeutic strategy for the treatment of HNSCC

The anti-tumor effects of cetuximab in combination with VTX-2337 are T cell dependent

Abstract The Toll-like receptor 8 (TLR8) agonist VTX-2337 (motolimod) is an anti-cancer immunotherapeutic agent that is believed to augment natural killer (NK) and dendritic cell (DC) activity. The goal of this work is to examine the role of TLR8 expression/activity in head and neck squamous cell carcinoma (HNSCC) to facilitate the prediction of responders to VTX-2337-based therapy. The prognostic role of TLR8 expression in HNSCC patients was assessed by TCGA and tissue microarray analyses. The anti-tumor effect of VTX-2337 was determined in SCCVII/C3H, mEERL/C57Bl/6 and TUBO-human EGFR/BALB/c syngeneic mouse models. The effect of combined VTX-2337 and cetuximab treatment on tumor growth, survival and immune cell recruitment was assessed. TLR8 expression was associated with CD8+ T cell infiltration and favorable survival outcomes. VTX-2337 delayed tumor growth in all 3 syngeneic mouse models and significantly increased the survival of cetuximab-treated mice. The anti-tumor effects of VTX-2337+ cetuximab were accompanied by increased splenic lymphoid DCs and IFNγ+ CD4+ and tumor-specific CD8+ T cells. Depletion of CD4+ T cells, CD8+ T cells and NK cells were all able to abolish the anti-tumor effect of VTX-2337+ cetuximab. Altogether, VTX-2337 remains promising as an adjuvant for cetuximab-based therapy however patients with high TLR8 expression may be more likely to derive benefit from this drug combination compared to patients with low TLR8 expression

BSO+AUR sensitized HNSCC cells to Erlotinib.

<p>Confluent FaDu, Cal-27, SCC-25 and SQ20B cells were treated with 1 mM BSO and or 0.5 µM AUR in combination with 10 µM Erlotinib (ERL) for 24 h. Clonogenic cell survival data were normalized to control (CON) cells. Error bars represent the standard error of the mean (SEM) of N = 3 experiments. *, p<0.05 versus CON; ¥, p<0.05 versus CON, BSO and AUR; £, p<0.05 versus ERL; §, p<0.05 versus all other treatment groups.</p