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Background Triple-negative breast cancer (TNBC) has been associated with a robust tumor immune infiltrate. Tumor-infiltrating lymphocytes (TILs) in TNBC have been demonstrated a prognostic value. The mitogen-activated protein kinase (MAPK) signaling pathway have been shown to regulate the immune response with the production of immunomodulatory cytokines, such as TNFα, interleukin (IL)-1, IL-10, and IL-12. Clinical studies have shown that the high expression level of Extracellular signal–related kinase (ERK), a member of the MAPK pathway, correlates with shorter survival in TNBC patients. Accordingly, ERK is a potential target for anti-tumor and cancer immunotherapy. In this study, we aimed to investigate a MEK inhibitor cobimetinib and elucidate whether the MEK/ERK pathway is implicated in immunogenic cell death (ICD) and/or other immunomodulatory effects. Methods Mouse TNBC cell line 4T1 was treated with cobimetinib. The cell viability and cell apoptosis were determined by MTT assay and flow cytometric analysis. Cobimeinib-induced damage-associated molecular patterns (DAMPs), such as such as cell-surface translocation of calreticulin (CRT), extracellular release of ATP, and increase in high-mobility group box protein B1 (HMGB1) release from dying tumor cells, were examined by immunoblotting and flow cytometric analysis. Further, the molecular mechanisms involving cobimetinib-induced cell death were examined by Immunoblotting. Last but not least, establishment of 4T1 animal model in immunocompetent and immunodeficient mice was conducted to investigate the efficacy of cobimetinib in restoration of immunosurveillance and cancer metastasis in vivo. Results The results showed that cobimetinib impaired cell proliferation and induced cell apoptosis in a dose-dependent manner in 4T1 cells. Importantly, cobimetinib treated 4T1 cells elicited ICD, by increasing HMGB1 and ATP release, and by promoting membrane exposure of CRT. The molecular mechanisms involved in cobimetinib-induced DAMPs were partially through the downregulation of p-ERK expression. Moreover, cobimetinib induced processing of procaspase-3 and -8 in 4T1 cells, thereby resulting in caspase activation. In addition, 4T1 tumor bearing immunocompetent mice treated with cobimetinib showed reduced size of primary tumors, fewer lung metastases and increased survival. In addition, we noticed that the tumor-suppressive effects of cobimetinib were much stronger in immunocompetent mice than in immunodeficient mice, evident by distinct mice survival in drug-treated mice. Flow cytometric analysis of murine splenocytes also revealed that cobimetinib treatment increased total number of CD8+ T cells, dendritic cell maturation, and suppressed the number of Myeloid-derived suppressor cells (MDSCs) in immunocompetent mice. Conclusions Our findings suggested that the MEK/ERK inhibitor cobimetinib induces ICD in vitro and exerts additional immune-modulatory effects in immunocompetent TNBC mice model. Our study highlights the possibility for the use of cobimetinib as an ICD inducer and immunomodulator for therapeutic intervention in TNBC. Keywords Cobimetinib, immunogenic cell death, MAPK, ERK phosphorylation, immune regulation Citation Format: Liu C-Y, Lau K-Y, Chen J-L, Chu P-Y, Huang C-T, Wang W-L, Lien P-J, Tseng L-M. MEK inhibitor cobimetinib induces immunogenic cell death and immune-modulatory effects in triple negative breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P4-06-21.

Groundwater at many military factory, munition storage and maneuver sites is contaminated by explosives chemicals that were released into the subsurface. The 2,4,6-trinitrotoluene (TNT) is among the most common explosive pollutants. In this study, two TNT-degrading strains, isolated from TNT-contaminated soils and wastewater sludge, were applied for TNT biodegradation. Based on the 16S rDNA sequence analyses, these two bacterial strains were identified as Achromobacter sp. and Klebsiella sp. via biochemical and DNA analyses. Microcosm study was conducted to evaluate the feasibility and efficiency of TNT biodegradation under aerobic conditions. Results indicate that TNT degradation by-products were detected in microcosms (inoculated with Achromobacter sp. and Klebsiella sp.) with cane molasses addition. Klebsiella sp. and Achromobacter sp. used TNT as the nitrogen source and caused completely removal of TNT. Two possible TNT biodegradation routes could be derived: (1) part of the TNT was transformed to nitrotoluene then transformed to nitrobenzene followed by the nitro substitute process, and trinitrobenzene, dinitrobenzene, and nitrobenzene were detected; and (2) TNT was transformed via the nitro substitute mechanism, and dinitrotoluene followed by nitrotoluene isomers were detected. The initial TNT degradation involved the reduction or removal of the nitro substitute to an amino derivative or free nitrite. Results show that the second route was the dominant TNT biodegradation pathway. The produced by-products were also degraded without significant accumulation during the degradation process. These findings would be helpful in designing a practical system inoculated with isolated TNT degradation strains for the treatment of TNT-contained groundwater.

Petroleum hydrocarbon–contaminated soil and groundwater is a worldwide environmental problem, which results in environmental hazard and human health risk problems. Because petroleum is a complex composition mixture rather than a single compound, health risk assessment for a petroleum hydrocarbon–contaminated site is a complicated process. In this study, a modified total petroleum hydrocarbons (TPH) fraction method was applied to determine the health risk level for each TPH fraction. The concentrations and toxicity data of total of 13 TPH fraction categories were evaluated and used for risk calculation. Results show that up to 1,772 mg/kg of TPH concentration was observed in soils collected from the studied site. Results indicate that benzene was the most concerning chemical that appeared in TPH. The calculated cancer risk for benzene was 4.48×10−7, which was lower than the minimum total cancer risk level (1×10−6). The calculated hazard quotient for the noncarcinogenic compounds was slightly highe...