Biology subjects

Ambs, S.

Publications and source records attributed to Ambs, S..

5 recordsLinked to original sources

bioRxiv2023

Interferon-gamma is Quintessential for NOS and COX Expression in ER- Breast Tumors that Lead to Poor Outcome

A strong correlation between NOS2 and COX2 tumor expression and poor clinical outcomes in ER-breast cancer has been established. However, mechanisms of tumor induction of these enzymes are unclear. Analysis of The Cancer Genome Atlas (TCGA) revealed correlations between NOS2 and COX2 expression and Th1 cytokines. Herein, single cell RNAseq analysis of TNBC cells shows potent NOS2 and COX2 induction by IFN{gamma} combined with IL1{beta} or TNF. Given that IFN{gamma} is secreted by cytolytic lymphocytes, which improve clinical outcomes, this role of IFN{gamma}presents a dichotomy. To explore this conundrum, tumor NOS2, COX2, and CD8+ T cells were spatially analyzed in aggressive ER-, TNBC, and HER2+ breast tumors. High expression and clustering of NOS2-expressing tumor cells occurred at the tumor/stroma interface in the presence of stroma-restricted CD8+ T cells. High expression and clustering of COX2-expressing tumor cells extended into immune desert regions in the tumor core where CD8+ T cell penetration was limited or absent. Moreover, high NOS2-expressing tumor cells were proximal to areas with increased satellitosis suggestive of cell clusters with a higher metastatic potential. Further in vitro experiments revealed that IFN{gamma}+IL1{beta}/TNF increased elongation and migration of treated tumor cells. This spatial analysis of the tumor microenvironment provides important insight of distinct neighborhoods where stroma-restricted CD8+ T cells exist proximal to NOS2-expressing tumor niches that could have increased metastatic potential.

cancer biology↗

bioRxiv2023

SERPINB3 induces the basal-like/squamous subtype and enhances disease progression in pancreatic cancer

Pancreatic cancer is a heterogeneous disease with distinct subtypes. Here, we investigated candidate driver genes of the highly aggressive basal-like/squamous molecular subtype of pancreatic ductal adenocarcinoma (PDAC). Integrative transcriptomic analyses identified the upregulated serine/cysteine protease inhibitor, SERPINB3 (squamous cell carcinoma antigen 1, SCCA1) in basal-like/squamous PDAC using discovery and validation approaches. Upregulation of SERPINB3 associated with decreased patient survival and a transcriptome profile indicative of the basal-like/squamous subtype. In human PDAC cell lines, SERPINB3 transgene expression enhanced their invasion capability. Moreover, upregulated expression of SERPINB3 in AsPC-1 cells resulted in enhanced lung metastasis in an orthotopic xenograft model. Molecular analysis of the primary tumor xenografts indicated activation of pathways related to metastasis, increased oxidative damage, and angiogenesis when SERPINB3 was upregulated. Furthermore, metabolomic analysis, using patient cohorts and PDAC cell lines showed a distinct metabolic pattern closely associated with both SERPINB3 and the basal-like/squamous subtype, which included upregulation of carnitine/acylcarnitine, amino acid, glutathione, and purine metabolic pathways, and glycolysis. Further RNA-seq and metabolomic analyses indicated that SERPINB3 may potentially induce the basal-like/squamous subtype and metabolic reprogramming through MYC activation. Taken together, our findings identified SERPINB3 as a candidate marker gene for the basal-like/squamous subtype, which may contribute to the disease aggressiveness in this subtype of PDAC. Abbreviations8-Hydroxy-2-deoxyguanosine (8-OHdG), Diaminobenzene (DAB), Gene Set Enrichment Analysis (GSEA), Human Metabolome Technologies, Inc. (HMT), Immunohistochemistry (IHC), Ingenuity pathway analysis (IPA), Pancreatic ductal adenocarcinoma (PDAC), Serine/Cysteine Proteinase Inhibitor Family B Member 3 (SERPINB3) Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=132 SRC="FIGDIR/small/534766v1_ufig1.gif" ALT="Figure 1"> View larger version (50K): org.highwire.dtl.DTLVardef@8209f5org.highwire.dtl.DTLVardef@15be96dorg.highwire.dtl.DTLVardef@13a0c6corg.highwire.dtl.DTLVardef@58b2f_HPS_FORMAT_FIGEXP M_FIG C_FIG HighlightsO_LISERPINB3 is upregulated in basal-like/squamous PDAC and associates with decreased patient survival C_LIO_LISERPINB3 promotes differentiation into the basal-like/squamous subtype and enhances invasion and metastasis of PDAC C_LIO_LISERPINB3 induces metabolic reprogramming and MYC activation and a metabolic signature indicative of basal-like/squamous PDAC C_LI

cancer biology↗

bioRxiv2022

NOS2 and COX2 Blockade Limits TNBC Disease Progression and Alters CD8+ T Cell Spatial Orientation and Density

Anti-tumor immune polarization is a key predictor of clinical outcomes to cancer therapy. An emerging concept influencing clinical outcome involves the spatial location of CD8+ T cells, within the tumor. Our earlier work demonstrated immunosuppressive effects of NOS2/ COX2 tumor expression. Here, we show that NOS2/COX2 levels influence the polarization and spatial location of lymphoid cells including CD8+ T cells. Importantly, elevated tumor NOS2/COX2 correlated with exclusion of CD8+ T cells from the tumor epithelium. In contrast, tumors expressing low NOS2/COX2 had increased CD8+ T cell penetration into the tumor epithelium. Consistent with a causative relationship between these observations, pharmacological inhibition of COX2 with indomethacin dramatically reduced tumor growth of the 4T1 model of TNBC in both WT and Nos2-/- mice. This regimen led to complete tumor regression in [~]20% of tumor-bearing Nos2-/- mice, and these animals were resistant to tumor rechallenge. Th1 cytokines were elevated in the blood of treated mice and intratumoral CD4+ and CD8+ T cells were higher in mice that received indomethacin when compared to control untreated mice. Multiplex immunofluorescence imaging confirmed our phenotyping results and demonstrated that targeted Nos2/Cox2 blockade improved CD8+ T cell penetration into the 4T1 tumor core. These findings are consistent with our observations in low NOS2/COX2 expressing breast tumors` proving that COX2 activity is responsible for limiting the spatial distribution of effector T cells in TNBC. Together these results suggest that clinically available NSAIDs may provide a cost-effective, novel immunotherapeutic approach for treatment of aggressive tumors including triple negative breast cancer.

cancer biology↗

bioRxiv2022

Stabilization of E-cadherin adhesions by COX-2/GSK3β signaling is a targetable pathway in metastatic breast cancer

Metastatic progression and treatment-resistance of breast cancer has been associated with epithelial-mesenchymal-transition including downregulation of E-cadherin (CDH1) expression, which can be initiated by inflammatory mediators such as COX-2. Recently, E-cadherin-mediated, cluster-based metastasis and treatment resistance has become more appreciated, though the mechanisms that maintain E-cadherin expression in this context are unknown. Through studies of inflammatory breast cancer and an in vitro tumor cell emboli culture paradigm, we identified a role for COX-2, a target gene of C/EBP{delta}, or its metabolite PGE2 in promoting protein stability of E-cadherin, {beta}-catenin and p120 catenin through inhibition of GSK3{beta}, without affecting CDH1 mRNA. The COX-2 inhibitor celecoxib downregulated E-cadherin complex proteins and caused cell death. Co-expression of E-cadherin and COX-2 was seen in breast cancer patients with poor outcome and, along with inhibitory GSK3{beta} phosphorylation, in patient-derived xenografts of triple negative breast cancer. Celecoxib alone decreased E-cadherin protein expression within xenograft tumors, reduced circulating tumor cells and clusters, and in combination with paclitaxel attenuated or regressed lung metastases. This study uncovered a mechanism by which metastatic breast cancer cells can maintain E-cadherin-mediated cell-cell adhesions and cell survival, suggesting that patients with COX-2+/E-cadherin+ breast cancer may benefit from targeting of the PGE2 signaling pathway.

cancer biology↗

bioRxiv2022

Pharmacometabolomics reveals urinary diacetylspermine as a biomarker of doxorubicin effectiveness in triple negative breast cancer

Triple-negative breast cancer (TNBC) patients receive chemotherapy treatment, including doxorubicin, due to the lack of targeted therapies. Drug resistance is a major cause of treatment failure in TNBC and therefore, there is a need to identify biomarkers that determine effective drug response. Here, a pharmacometabolomics study was performed using TNBC patient-derived xenograft models to detect urinary metabolic biomarkers of doxorubicin effectiveness. Diacetylspermine was identified as a urine metabolite that robustly changed in response to effective doxorubicin treatment, which persisted after the final dose. Diacetylspermine was directly traced back to the tumor and correlated with tumor volume. Ex vivo tumor slices revealed that doxorubicin directly increases diacetylspermine production by increasing tumor spermidine/spermine N1-acetyltransferase 1 expression and activity, which was corroborated by elevated polyamine flux. In breast cancer patients, tumor diacetylspermine was elevated compared to matched non-cancerous tissue and increased in HER2+ and TNBC compared to ER+ subtypes. In addition, 12-hour urine diacetylspermine was associated with breast cancer tumor volume and poor tumor grade. This study describes a pharmacometabolomics strategy for identifying cancer metabolic biomarkers that indicate drug response. Our findings characterize urine diacetylspermine as a non-invasive biomarker of doxorubicin effectiveness in TNBC.

cancer biology↗