The scaffold protein p140Cap limits ERBB2-mediated breast cancer progression interfering with Rac GTPase-controlled circuitries.

The docking protein p140Cap negatively regulates tumour cell features. Its relevance on breast cancer patient survival, as well as its ability to counteract relevant cancer signalling pathways, are not fully understood. Here we report that in patients with ERBB2-amplified breast cancer, a p140Cap-positive status associates with a significantly lower probability of developing a distant event, and a clear difference in survival. p140Cap dampens ERBB2- positive tumour cell progression, impairing tumour onset and growth in the NeuT mouse model, and counteracting epithelial mesenchymal transition, resulting in decreased metastasis formation. One major mechanism is the ability of p140Cap to interfere with ERBB2- dependent activation of Rac GTPase-controlled circuitries. Our findings point to a specific role of p140Cap in curbing the aggressiveness of ERBB2-amplified breast cancers and suggest that, due to its ability to impinge on specific molecular pathways, p140Cap may represent a predictive biomarker of response to targeted anti-ERBB2 therapies

Cancer Metabolic Subtypes and Their Association with Molecular and Clinical Features

The alterations of metabolic pathways in cancer have been investigated for many years, beginning long before the discovery of the role of oncogenes and tumor suppressors, and the last few years have witnessed renewed interest in this topic. Large-scale molecular and clinical data on tens of thousands of samples allow us to tackle the problem from a general point of view. Here, we show that transcriptomic profiles of tumors can be exploited to define metabolic cancer subtypes, which can be systematically investigated for associations with other molecular and clinical data. We find thousands of significant associations between metabolic subtypes and molecular features such as somatic mutations, structural variants, epigenetic modifications, protein abundance and activation, and with clinical/phenotypic data, including survival probability, tumor grade, and histological types, which we make available to the community in a dedicated web resource. Our work provides a methodological framework and a rich database of statistical associations, which will contribute to the understanding of the role of metabolic alterations in cancer and to the development of precision therapeutic strategies

Experimental approaches for studying semaphorin signals in tumor growth and metastasis in mouse models

Tumor growth and metastatic dissemination are complex multistep processes. They clearly depend on the intrinsic behavior of cancer cells, but are remarkably influenced by a variety of stromal cells present in the tumor microenvironment, which include those implicated in tumor angiogenesis, as well as bone marrow-derived cells recruited from the circulation. Moreover, multiple molecular signals exchanged between cancer cells and non-neoplastic stromal cells control tumor growth and metastasis; notably, members of the semaphorin family are emerging players in this scenario. In vivo tumor models represent the best setting for studying metastatic tumor progression, as they allow recapitulating the contribution of multiple cell types and signaling molecules in a complex tissue context, subject to pathophysiological local and systemic responses, such as metabolic changes, hypoxia, necrosis, fibrosis, inflammation, and cytokine release. Here, we describe some experimental approaches based on murine models to study the role of semaphorin signaling in tumor growth and metastatic progression in vivo

Acquired resistance to PRMT5 inhibition induces concomitant collateral sensitivity to paclitaxel

Significance Resistance to therapeutics is a challenge when treating cancer patients. Cancer can become resistant to therapies in distinct, unpredictable ways. Therefore, it is important to understand how resistance occurs to enable development of second-line or combination treatment strategies. This study develops cells that are resistant to inhibitors of protein arginine methyltransferase 5 (PRMT5), which is up-regulated in many cancers and being targeted in current clinical trials. We show that resistant lung adenocarcinoma cells are now sensitive to the widely used chemotherapy, paclitaxel, and identify a single gene, Stmn2 , that is responsible for both the resistance to inhibitors of PRMT5 and the collateral sensitivity to paclitaxel. Our data suggest that combined treatment with PRMT5 inhibitors and taxanes could be a success. </jats:p

Prostate-specific membrane antigen (PSMA) assembles a macromolecular complex regulating growth and survival of prostate cancer cells "in vitro" and correlating with progression "in vivo"

The expression of Prostate Specific-Membrane Antigen (PSMA) increases in high-grade prostate carcinoma envisaging a role in growth and progression. We show here that clustering PSMA at LNCaP or PC3-PSMA cell membrane activates AKT and MAPK pathways thus promoting proliferation and survival. PSMA activity was dependent on the assembly of a macromolecular complex including filamin A, beta1 integrin, p130CAS, c-Src and EGFR. Within this complex beta1 integrin became activated thereby inducing a c-Src-dependent EGFR phosphorylation at Y1086 and Y1173 EGF-independent residues. Silencing or blocking experiments with drugs demonstrated that all the complex components were required for full PSMA-dependent promotion of cell growth and/or survival in 3D culture, but that p130CAS and EGFR exerted a major role. All PSMA complex components were found assembled in multiple samples of two high-grade prostate carcinomas and associated with EGFR phosphorylation at Y1086. The expression of p130CAS and pEGFRY1086 was thus analysed by tissue micro array in 16 castration-resistant prostate carcinomas selected from 309 carcinomas and stratified from GS 3+4 to GS 5+5. Patients with Gleason Score 645 resulted negative whereas those with GS 655 expressed p130CAS and pEGFRY1086 in 75% and 60% of the cases, respectively.Collectively, our results demonstrate for the first time that PSMA recruits a functionally active complex which is present in high-grade patients. In addition, two components of this complex, p130CAS and the novel pEGFRY1086, correlate with progression in castration-resistant patients and could be therefore useful in therapeutic or surveillance strategies of these patients

SP1 and STAT3 Functionally Synergize to Induce the RhoU Small GTPase and a Subclass of Non-canonical WNT Responsive Genes Correlating with Poor Prognosis in Breast Cancer

Breast cancer is a heterogeneous disease whose clinical management is very challenging. Although specific molecular features characterize breast cancer subtypes with different prognosis, the identification of specific markers predicting disease outcome within the single subtypes still lags behind. Both the non-canonical Wingless-type MMTV Integration site (WNT) and the Signal Transducer and Activator of Transcription (STAT)3 pathways are often constitutively activated in breast tumors, and both can induce the small GTPase Ras Homolog Family Member U RhoU. Here we show that RhoU transcription can be triggered by both canonical and non-canonical WNT ligands via the activation of c-JUN N-terminal kinase (JNK) and the recruitment of the Specificity Protein 1 (SP1) transcription factor to the RhoU promoter, identifying for the first time SP1 as a JNK-dependent mediator of WNT signaling. RhoU down-regulation by silencing or treatment with JNK, SP1 or STAT3 inhibitors leads to impaired migration and invasion in basal-like MDA-MB-231 and BT-549 cells, suggesting that STAT3 and SP1 can cooperate to induce high RhoU expression and enhance breast cancer cells migration. Moreover, in vivo concomitant binding of STAT3 and SP1 defines a subclass of genes belonging to the non-canonical WNT and the Interleukin (IL)-6/STAT3 pathways and contributing to breast cancer aggressiveness, suggesting the relevance of developing novel targeted therapies combining inhibitors of the STAT3 and WNT pathways or of their downstream mediators

NAMPT in drug-resistant melanoma: linking NAMPT-dependent metabolic reprogramming and immune regulation

Introduction Targeted-therapy and immune checkpoint inhibitors (ICIs) have notably improved the treatment of BRAF-mutated metastatic melanoma (MM) patients; however resistance to treatment dramatically impacts on the survival of patients. BRAF(i)nhibitors-resistant MM cells showed increased amounts of NAD, an essential redox cofactor, supporting their metabolic adaptations underlying the acquisition of drug resistance. This was obtained selectively overexpressing the rate-limiting NAD-biosynthetic enzyme nicotinamide phosphoribosyltransferase (NAMPT). NAMPT-NAD axis becomes a driver of melanoma progression and resistance to BRAFi, that it may be therapeutically targeted. Material and Method NAMPT-NAD axis was studied using biochemical, enzymatic, immunohistochemical assays. Immunoprecipitation of NAMPT following mass spectrometry (MS) analysis was used to define NAMPT interactome. In silico analysis using TCGA database, western blot analysis and RT-PCR were used to detect and confirm protein expression and signaling pathways activation. Results and discussion The BRAF oncogenic signaling and NAMPT expression are molecularly linked. We found that mutations in the BRAF oncogene positively correlate with NAMPT expression in TCGA melanoma cohort and in tissue from MM patients. The over-expression of NAMPT correlates with its gene amplification. Analyzing the nature of this genetic amplification we found a co-amplification of others genes including PIK3CG that we started to evaluate functionally. A second set of preliminary data revealed a significant increase in the nuclear localization of NAMPT in resistant cells, also as NAMPT nuclear fraction chromatin-bound. We performed NAMPT immunoprecipitation following MS in cellular extract to identify NAMPT-interacting proteins. Data showed enrichment of NAMPT-interacting nuclear proteins and proteins involved in RNA processing, translation, metabolic processes, cellular response to stress and immune response among others. Starting to analyze NAMPT-immune gene signature relationship we found in TCGA melanoma cohort a positive correlation between NAMPT expression and interferon signaling, including CD274, IRF1, STAT1 genes that will be further investigated. Conclusion The multiple roles of NAMPT as intracellular and soluble protein are known; here we speculate that NAMPT could have an essential and unknown function in the nucleus and in regulating immune responses, with a possible impact on ICIs activities