In addition to oncogenic drivers, signaling nodes can critically modulate cancer-related cellular networks to strength tumor hallmarks. We identify G-protein-coupled receptor kinase 2 (GRK2) as a relevant player in breast cancer. GRK2 is up-regulated in breast cancer cell lines, in spontaneous tumors in mice, and in a proportion of invasive ductal carcinoma patients. Increased GRK2 functionality promotes the phosphorylation and activation of the Histone Deacetylase 6 (HDAC6) leading to de-acetylation of the Prolyl Isomerase Pin1, a central modulator of tumor progression, thereby enhancing its stability and functional interaction with key mitotic regulators. Interestingly, a correlation between GRK2 expression and Pin1 levels and de-acetylation status is detected in breast cancer patients. Activation of the HDAC6-Pin1 axis underlies the positive effects of GRK2 on promoting growth factor signaling, cellular proliferation and anchorage-independent growth in both luminal and basal breast cancer cells. Enhanced GRK2 levels promote tumor growth in mice, whereas GRK2 down-modulation sensitizes cells to therapeutic drugs and abrogates tumor formation. Our data suggest that GRK2 acts as an important onco-modulator by strengthening the functionality of key players in breast tumorigenesis such as HDAC6 and Pin1.

BackgroundRecent reports have identified distinct genomic patterns in ovarian carcinoma, including proliferative and mesenchymal-like groups, with worse outcome. The exact mechanisms driving the onset and progression of these tumors are still poorly understood. Additionally, researchers are concerned about the correct subtype stratification of the available cell line models, and the exploration of alternatives to monolayer culture. Identification of biomarkers to stratify cell lines, characterization of important processes as epithelial-mesenchymal transition (EMT), and the use of three-dimensional (3D) cultures as alternative models could be useful for cell line classification.Methods and ResultsIn this work, we present a descriptive analysis of 16 commonly used ovarian cancer cell lines. We have studied their morphology in 2- and 3D culture, and their response to cisplatin, observing in the majority of them an increased resistance in 3D. We have also performed an immunohistochemical analysis for proliferation marker Ki-67, and EMT related markers to establish phenotypes. Epithelial cells tend to show higher proliferative rates, and mesenchymal cells show an increase in EMT related markers, especially when cultured in 3D conditions.ConclusionsWe have stated the complex heterogeneity of ovarian cancer models, resembling primary tumors, agreeing with the argument that the cell line model for in vitro experiments must be carefully chosen. Our results also support that tridimensional culture could be a very helpful alternative in ovarian cancer research. Regarding EMT, a very important process for the development of this disease, some related biomarkers might be further characterized for their role in this disease development.

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Low-grade, early-stage endometrial carcinoma (EC) is the most frequent malignant tumor of the uterine corpus. However, the molecular alterations that underlie these tumors are far from being fully understood. The purpose of this study is to describe dysregulated molecular pathways from EC patients. Sixteen samples of tumor tissue and paired healthy controls were collected and both were subjected to mass spectrometry (MS)/MS proteomic analysis. Gene ontology and pathway analysis was performed to discover dysregulated pathways and/or proteins using different databases and bioinformatic tools. Dysregulated pathways were cross-validated in an independent external cohort. Cell signaling, immune response, and cell death-associated pathways were robustly identified. The SLIT/ROBO signaling pathway demonstrated dysregulation at the proteomic and transcriptomic level. Necroptosis and ferroptosis were cell death-associated processes aberrantly regulated, in addition to apoptosis. Immune response-associated pathways showed a dominance of innate immune responses. Tumor immune infiltrates measured by immunofluorescence demonstrated diverse lymphoid and myeloid populations. Our results suggest a role of SLIT/ROBO, necroptosis, and ferroptosis, as well as a prominent role of innate immune response in low-grade, early-stage EC. These results could guide future research in this group of tumors.