JAK-STAT signaling in inflammatory breast cancer enables chemotherapy-resistant cell states

Inflammatory breast cancer (IBC) is a difficult-to-treat disease with poor clinical outcomes due to high risk of metastasis and resistance to treatment. In breast cancer, CD44+CD24- cells possess stem cell-like features and contribute to disease progression, and we previously described a CD44+CD24-pSTAT3+ breast cancer cell subpopulation that is dependent on JAK2/STAT3 signaling. Here we report that CD44+CD24- cells are the most frequent cell-type in IBC and are commonly pSTAT3+. Combination of JAK2/STAT3 inhibition with paclitaxel decreased IBC xenograft growth more than either agent alone. IBC cell lines resistant to paclitaxel and doxorubicin were developed and characterized to mimic therapeutic resistance in patients. Multi-omic profiling of parental and resistant cells revealed enrichment of genes associated with lineage identity and inflammation in chemotherapy resistant derivatives. Integrated pSTAT3 ChIP-seq and RNA-seq analyses showed pSTAT3 regulates genes related to inflammation and epithelial to mesenchymal transition (EMT) in resistant cells, as well as PDE4A, a cAMP-specific phosphodiesterase. Metabolomic characterization identified elevated cAMP signaling and CREB as a candidate therapeutic target in IBC. Investigation of cellular dynamics and heterogeneity at the single cell level during chemotherapy and acquired resistance by CyTOF and single cell RNA-seq identified mechanisms of resistance including a shift from luminal to basal/mesenchymal cell states through selection for rare pre-existing subpopulations or an acquired change. Lastly, combination treatment with paclitaxel and JAK2/STAT3 inhibition prevented the emergence of the mesenchymal chemo-resistant subpopulation. These results provide mechanistic rational for combination of chemotherapy with inhibition of JAK2/STAT3 signaling as a more effective therapeutic strategy in IBC

The relevance of the lymph node ratio as predictor of prognosis is higher in HPV-negative than in HPV-positive oropharyngeal squamous cell carcinoma

Objectives: Lymph node ratio (LNR) is an established predictor in different entities of carcinoma, including head and neck malignancies. In oropharyngeal squamous cell carcinoma (OPSCC), lymph node involvement differs between human papilloma virus (HPV)-positive and HPV-negative tumours. Herein, we evaluate the impact of HPV association on the concept of LNR. Methods: 88 surgically treated patients were included in this retrospective chart review. HPV-positive and HPV-negative OPSCC were evaluated for prediction of outcome by LNR separately. The endpoints were 5-year overall survival (OS) and recurrence-free survival (RFS). Results: The OS of all patients was 60.1%. In univariate analysis, LNR was a significant predictor of overall survival rate (P=. 008) in OPSCC independently of the HPV status, as well as extracapsular spread (ECS). T-classification was only a significant predictor in the univariate analysis in HPV-positive OPSCC carcinoma. However, in the multivariate analysis LNR remained predictor of prognosis in all OPSCC and in HPV-negative OPSCC. In patients with HPV-positive OPSCC, only T-classification reached significance to predict OS. Conclusion: Prognosis of primarily operated HPV-positive patients might be more dependent on the extent of primary tumour site, whereas prognosis of HPVnegative patients is based more on cervical metastatic spread, represented by LNR

Downregulation of the (1)- and (1)-subunit of sGC in Arterial Smooth Muscle Cells of OPSCC Is HPV-Independent

The nitric oxide (NO)-sensitive soluble guanylyl cyclase (sGC) is a heterodimeric enzyme with an and subunit. NO binds to heme of the (1)-subunit of sGC, activates the enzyme in the reduced heme iron state in vascular smooth muscle cells (VSMCs), and generates cGMP-inducing vasodilatation and suppression of VSMC proliferation. In the complex tumor milieu with higher levels of reactive oxygen species (ROS), sGC heme iron may become oxidized and insensitive to NO. To change sGC from an NO-insensitive to NO-sensitive state or NO-independent manner, protein expression of sGC in VSMC is required. Whether sGC(11) exists at the protein level in arterial VSMCs of oropharyngeal squamous cell carcinoma (OPSCC) is unknown. In addition, whether differences in the genetic profile between human papillomavirus (HPV)-positive and HPV-negative OPSCC contributes to the regulation of sGC(11) is unclear. Therefore, we compared the effects of HPV-positive and HPV-negative OPSCC on the expression of sGC(11) in arterial VSMCs from tumor-free and tumor-containing regions of human tissue sections using quantitative immunohistochemistry. In comparison to the tumor-free region, we found a decrease in expression of both (1)- and (1)-subunits in the arterial VSMC layer of the tumor-containing areas. The OPSCC-induced significant downregulation of the (1)- and (1)-subunits of sGC in arterial VSMC was HPV-independent. We conclude that the response of sGC to NO in tumor arterial VSMCs may be impaired by oxidation of the heme of the (1)-subunit, and thus, (1)- and (1)-subunits of sGC could be targeted to degradation under oxidative stress in OPSCC in an HPV-independent manner. The degradation of sGC(11) in VSMCs may result in increased proliferation of VSMCs, promoting tumor arteriogenesis in OPSCC. This can be interrupted by preserving the active heterodimer sGC(11) in arterial VSMCs

DS_10.1177_0022034518774531 – Supplemental material for Downregulation of the α₁- and β₁-subunit of sGC in Arterial Smooth Muscle Cells of OPSCC Is HPV-Independent

<p>Supplemental material, DS_10.1177_0022034518774531 for Downregulation of the α₁- and β₁-subunit of sGC in Arterial Smooth Muscle Cells of OPSCC Is HPV-Independent by Y. Korkmaz, H.C. Roggendorf, O.G. Siefer, J. Seehawer, T. Imhof, M. Plomann, W. Bloch, A. Friebe and C.U. Huebbers in Journal of Dental Research</p

PTBP1-mediated alternative splicing regulates the inflammatory secretome and the pro-tumorigenic effects of senescent cells

Oncogene-induced senescence is a potent tumor-suppressive response. Paradoxically, senescence also induces an inflammatory secretome that promotes carcinogenesis and age-related pathologies. Consequently, the senescence-associated secretory phenotype (SASP) is a potential therapeutic target. Here, we describe an RNAi screen for SASP regulators. We identified 50 druggable targets whose knockdown suppresses the inflammatory secretome and differentially affects other SASP components. Among the screen candidates was PTBP1. PTBP1 regulates the alternative splicing of genes involved in intracellular trafficking, such as EXOC7, to control the SASP. Inhibition of PTBP1 prevents the pro-tumorigenic effects of the SASP and impairs immune surveillance without increasing the risk of tumorigenesis. In conclusion, our study identifies SASP inhibition as a powerful and safe therapy against inflammation-driven cancer