Combinatorial strategies targeting NEAT1 and AURKA as new potential therapeutic options for multiple myeloma.

Multiple myeloma (MM) is a dreadful disease, marked by the uncontrolled proliferation of clonal plasma cells (PCs) within the bone marrow (BM). MM is characterized by a highly heterogeneous clinical and molecular background, supported by severe genomic alterations. Important deregulation of long non-coding RNAs (lncRNAs) expression has been reported in MM patients, influencing progression and therapy resistance. NEAT1 is a lncRNA essential for nuclear paraspeckles and involved in gene expression regulation. We showed that NEAT1 supports MM proliferation making this lncRNA an attractive therapeutic candidate. Here, we used a combinatorial strategy integrating transcriptomic and computational approaches with functional high-throughput drug screening, to identify compounds that synergize with NEAT1 inhibition in restraining MM cells growth. AUKA inhibitors were identified as top-scoring drugs in these analyses. We showed that the combination of NEAT1 silencing and AURKA inhibitors in MM profoundly impairs microtubule organization and mitotic spindle assembly, finally leading to cell death. Analysis of the large publicly CoMMpass dataset showed that in MM patients AURKA expression is strongly associated with reduced progression-free (p < 0.0001) and overall survival probability (p < 0.0001) and patients displaying high expression levels of both NEAT1 and AURKA have a worse clinical outcome. Finally, using RNA-sequencing data from NEAT1 knockdown (KD) MM cells, we identified the AURKA allosteric regulator TPX2 as a new NEAT1 target in MM and as a mediator of the interplay between AURKA and NEAT1, therefore providing a possible explanation of the synergistic activity observed upon their combinatorial inhibition.

Molecular and Histopathological Characterization of Metastatic Cutaneous Squamous Cell Carcinomas: A Case-Control Study.

BACKGROUND: A subset of patients affected by cutaneous squamous cell carcinoma (cSCC) can exhibit locally invasive or metastatic tumors. Different staging classification systems are currently in use for cSCC. However, precise patient risk stratification has yet to be reached in clinical practice. The study aims to identify specific histological and molecular parameters characterizing metastatic cSCC. METHODS: Patients affected by metastatic and non-metastatic cSCC (controls) were included in the present study and matched for clinical and histological characteristics. Skin samples from primary tumors were revised for several histological parameters and also underwent gene expression profiling with a commercially available panel testing 770 different genes. RESULTS: In total, 48 subjects were enrolled in the study (24 cases, 24 controls); 67 genes were found to be differentially expressed between metastatic and non-metastatic cSCC. Most such genes were involved in immune regulation, skin integrity, angiogenesis, cell migration and proliferation. CONCLUSION: The combination of histological and molecular profiles of cSCCs allows the identification of features specific to metastatic cSCC, with potential implications for more precise patient risk stratification.

Linc00941 fuels ribogenesis and protein synthesis by supporting robust cMYC translation in malignant pleural mesothelioma.

Malignant pleural mesothelioma is a rare and lethal cancer caused by exposure to asbestos. The highly inflammatory environment caused by fibers accumulation forces cells to undergo profound adaptation to gain survival advantages. Prioritizing the synthesis of essential transcripts is an efficient mechanism coordinated by multiple molecules, including long non-coding RNAs. Enhancing the knowledge about these mechanisms is an essential weapon in combating mesothelioma. Linc00941 correlates to bad prognosis in various cancers, but it is reported to partake in distinct and apparently irreconcilable processes. In this work, we report that linc00941 supports the survival and aggressiveness of mesothelioma cells by influencing protein synthesis and ribosome biogenesis. Linc00941 binds to the translation initiation factor eIF4G, promoting the selective protein synthesis of cMYC, which, in turn, enhances the expression of key genes involved in translation. We analyzed a retrospective cohort of 97 mesothelioma patients' samples from our institution, revealing that linc00941 expression strongly correlates with reduced survival probability. This discovery clarifies linc00941's role in mesothelioma and proposes a unified mechanism of action for this lncRNA involving the selective translation of essential oncogenes, reconciling the discrepancies about its function.

HELLS regulates transcription in T-cell lymphomas by reducing unscheduled R-loops and by facilitating RNAPII progression.

Chromatin modifiers are emerging as major determinants of many types of cancers, including Anaplastic Large Cell Lymphomas (ALCL), a family of highly heterogeneous T-cell lymphomas for which therapeutic options are still limited. HELLS is a multifunctional chromatin remodeling protein that affects genomic instability by participating in the DNA damage response. Although the transcriptional function of HELLS has been suggested, no clues on how HELLS controls transcription are currently available. In this study, by integrating different multi-omics and functional approaches, we characterized the transcriptional landscape of HELLS in ALCL. We explored the clinical impact of its transcriptional program in a large cohort of 44 patients with ALCL. We demonstrated that HELLS, loaded at the level of intronic regions of target promoters, facilitates RNA Polymerase II (RNAPII) progression along the gene bodies by reducing the persistence of co-transcriptional R-loops and promoting DNA damage resolution. Importantly, selective knockdown of HELLS sensitizes ALCL cells to different chemotherapeutic agents, showing a synergistic effect. Collectively, our work unveils the role of HELLS in acting as a gatekeeper of ALCL genome stability providing a rationale for drug design.

Accuracy of World Health Organisation-grade parameters (necrosis and mitotic activity) and foci of vascular invasion in predicting prognosis of papillary thyroid carcinoma. A case-control validation study.

AIMS: Tumour necrosis and/or increased mitoses define high-grade papillary thyroid carcinoma (PTC). It is unclear whether angioinvasion is prognostic for PTC. Cut-offs at five or more mitoses/2 mm2 and four or more angioinvasive foci have been empirically defined based upon data from all forms of aggressive non-anaplastic thyroid carcinomas. Performance of tumour necrosis, mitoses and vascular invasion in predicting distant metastases when specifically applied to PTC is undefined. METHODS: We analysed 50 consecutive PTC cases with distant metastases (DM-PTC): 16 synchronous and 34 metachronous. A total of 108 non-metastatic PTC (N-DM-PTC, 15.0-year median follow-up) were used as controls. Invasive encapsulated follicular variant PTC was excluded. Necrosis, mitoses and angioinvasion were quantified. Receiver operating characteristics (ROC) and area under the curve (AUC) analyses determined best sensitivity and specificity cut-offs predictive of distant metastases. RESULTS: Metastases correlated with necrosis (any extent = 43.8% all DM-PTC, 53.1% metachronous DM-PTC versus 5% N-DM-PTC; P < 0.001), mitoses (P < 0.001) and angioinvasion (P < 0.001). Mitoses at five or more per 2 mm2 was the best cut-off correlating with distant metastases: sensitivity/specificity 42.9%/97.2% all DM-PTC (AUC = 0.78), 18.8%/97.2% synchronous DM-PTC (AUC = 0.63), 54.6%/97.2% metachronous DM-PTC (AUC = 0.85). Angioinvasive foci at five or more was the best cut-off correlating with distant metastases: sensitivity/specificity 36.2%/91.7% all DM-PTC (AUC = 0.75), 25%/91.7% synchronous DM-PTC (AUC = 0.79) and 41.9%/91.7% metachronous DM-PTC (AUC = 0.73). Positive/negative predictive values (PPV/NPV) were: necrosis 22.6%/98.2%; five or more mitoses 32.3%/98.2%; five or more angioinvasive foci 11.8%/97.9%. After multivariable analysis, only necrosis and mitotic activity remained associated with DM-PTC. CONCLUSION: Our data strongly support PTC grading, statistically validating World Health Organisation (WHO) criteria to identify poor prognosis PTC. Angioinvasion is not an independent predictor of DM-PTC.

Mapping functional to morphological variation reveals the basis of regional extracellular matrix subversion and nerve invasion in pancreatic cancer.

Intratumor morphological heterogeneity of pancreatic ductal adenocarcinoma (PDAC) predicts clinical outcomes but is only partially understood at the molecular level. To elucidate the gene expression programs underpinning intratumor morphological variation in PDAC, we investigated and deconvoluted at single cell level the molecular profiles of histologically distinct clusters of PDAC cells. We identified three major morphological and functional variants that co-exist in varying proportions in all PDACs, display limited genetic diversity, and are associated with a distinct organization of the extracellular matrix: a glandular variant with classical ductal features; a transitional variant displaying abortive ductal structures and mixed endodermal and myofibroblast-like gene expression; and a poorly differentiated variant lacking ductal features and basement membrane, and showing neuronal lineage priming. Ex vivo and in vitro evidence supports the occurrence of dynamic transitions among these variants in part influenced by extracellular matrix composition and stiffness and associated with local, specifically neural, invasion.

The pancancer overexpressed NFYC Antisense 1 controls cell cycle mitotic progression through in cis and in trans modes of action.

Antisense RNAs (asRNAs) represent an underappreciated yet crucial layer of gene expression regulation. Generally thought to modulate their sense genes in cis through sequence complementarity or their act of transcription, asRNAs can also regulate different molecular targets in trans, in the nucleus or in the cytoplasm. Here, we performed an in-depth molecular characterization of NFYC Antisense 1 (NFYC-AS1), the asRNA transcribed head-to-head to NFYC subunit of the proliferation-associated NF-Y transcription factor. Our results show that NFYC-AS1 is a prevalently nuclear asRNA peaking early in the cell cycle. Comparative genomics suggests a narrow phylogenetic distribution, with a probable origin in the common ancestor of mammalian lineages. NFYC-AS1 is overexpressed pancancer, preferentially in association with RB1 mutations. Knockdown of NFYC-AS1 by antisense oligonucleotides impairs cell growth in lung squamous cell carcinoma and small cell lung cancer cells, a phenotype recapitulated by CRISPR/Cas9-deletion of its transcription start site. Surprisingly, expression of the sense gene is affected only when endogenous transcription of NFYC-AS1 is manipulated. This suggests that regulation of cell proliferation is at least in part independent of the in cis transcription-mediated effect on NFYC and is possibly exerted by RNA-dependent in trans effects converging on the regulation of G2/M cell cycle phase genes. Accordingly, NFYC-AS1-depleted cells are stuck in mitosis, indicating defects in mitotic progression. Overall, NFYC-AS1 emerged as a cell cycle-regulating asRNA with dual action, holding therapeutic potential in different cancer types, including the very aggressive RB1-mutated tumors.

BET inhibitors drive Natural Killer activation in non-small cell lung cancer via BRD4 and SMAD3.

Non-small-cell lung carcinoma (NSCLC) is the most common lung cancer and one of the pioneer tumors in which immunotherapy has radically changed patients' outcomes. However, several issues are emerging and their implementation is required to optimize immunotherapy-based protocols. In this work, we investigate the ability of the Bromodomain and Extra-Terminal protein inhibitors (BETi) to stimulate a proficient anti-tumor immune response toward NSCLC. By using in vitro, ex-vivo, and in vivo models, we demonstrate that these epigenetic drugs specifically enhance Natural Killer (NK) cell cytotoxicity. BETi down-regulate a large set of NK inhibitory receptors, including several immune checkpoints (ICs), that are direct targets of the transcriptional cooperation between the BET protein BRD4 and the transcription factor SMAD3. Overall, BETi orchestrate an epigenetic reprogramming that leads to increased recognition of tumor cells and the killing ability of NK cells. Our results unveil the opportunity to exploit and repurpose these drugs in combination with immunotherapy.

DIS3 depletion in multiple myeloma causes extensive perturbation in cell cycle progression and centrosome amplification.

DIS3 gene mutations occur in approximately 10% of patients with multiple myeloma (MM); furthermore, DIS3 expression can be affected by monosomy 13 and del(13q), found in roughly 40% of MM cases. Despite the high incidence of DIS3 mutations and deletions, the biological significance of DIS3 and its contribution to MM pathogenesis remain poorly understood. In this study we investigated the functional role of DIS3 in MM, by exploiting a loss-of-function approach in human MM cell lines. We found that DIS3 knockdown inhibits proliferation in MM cell lines and largely affects cell cycle progression of MM plasma cells, ultimately inducing a significant increase in the percentage of cells in the G0/G1 phase and a decrease in the S and G2/M phases. DIS3 plays an important role not only in the control of the MM plasma cell cycle, but also in the centrosome duplication cycle, which are strictly co-regulated in physiological conditions in the G1 phase. Indeed, DIS3 silencing leads to the formation of supernumerary centrosomes accompanied by the assembly of multipolar spindles during mitosis. In MM, centrosome amplification is present in about a third of patients and may represent a mechanism leading to genomic instability. These findings strongly prompt further studies investigating the relevance of DIS3 in the centrosome duplication process. Indeed, a combination of DIS3 defects and deficient spindle-assembly checkpoint can allow cells to progress through the cell cycle without proper chromosome segregation, generating aneuploid cells which ultimately lead to the development of MM.

Spatial Distribution of Immune Cells Drives Resistance to Neoadjuvant Chemotherapy in Triple-Negative Breast Cancer.

Neoadjuvant chemotherapy (NAC) alone or combined with target therapies represents the standard of care for localized triple-negative breast cancer (TNBC). However, only a fraction of patients have a response, necessitating better understanding of the complex elements in the TNBC ecosystem that establish continuous and multidimensional interactions. Resolving such complexity requires new spatially-defined approaches. Here, we used spatial transcriptomics to investigate the multidimensional organization of TNBC at diagnosis and explore the contribution of each cell component to response to NAC. Starting from a consecutive retrospective series of TNBC cases, we designed a case-control study including 24 patients with TNBC of which 12 experienced a pathologic complete response (pCR) and 12 no-response or progression (pNR) after NAC. Over 200 regions of interest (ROI) were profiled. Our computational approaches described a model that recapitulates clinical response to therapy. The data were validated in an independent cohort of patients. Differences in the transcriptional program were detected in the tumor, stroma, and immune infiltrate comparing patients with a pCR with those with pNR. In pCR, spatial contamination between the tumor mass and the infiltrating lymphocytes was observed, sustained by a massive activation of IFN-signaling. Conversely, pNR lesions displayed increased pro-angiogenetic signaling and oxygen-based metabolism. Only modest differences were observed in the stroma, revealing a topology-based functional heterogeneity of the immune infiltrate. Thus, spatial transcriptomics provides fundamental information on the multidimensionality of TNBC and allows an effective prediction of tumor behavior. These results open new perspectives for the improvement and personalization of therapeutic approaches to TNBCs.

The long non-coding RNA TAZ-AS202 promotes lung cancer progression via regulation of the E2F1 transcription factor and activation of Ephrin signaling.

Long non-coding RNAs (lncRNAs) are transcripts without coding potential that are pervasively expressed from the genome and have been increasingly reported to play crucial roles in all aspects of cell biology. They have been also heavily implicated in cancer development and progression, with both oncogenic and tumor suppressor functions. In this work, we identified and characterized a novel lncRNA, TAZ-AS202, expressed from the TAZ genomic locus and exerting pro-oncogenic functions in non-small cell lung cancer. TAZ-AS202 expression is under the control of YAP/TAZ-containing transcriptional complexes. We demonstrated that TAZ-AS202 is overexpressed in lung cancer tissue, compared with surrounding lung epithelium. In lung cancer cell lines TAZ-AS202 promotes cell migration and cell invasion. TAZ-AS202 regulates the expression of a set of genes belonging to cancer-associated pathways, including WNT and EPH-Ephrin signaling. The molecular mechanism underlying TAZ-AS202 function does not involve change of TAZ expression or activity, but increases the protein level of the transcription factor E2F1, which in turn regulates the expression of a large set of target genes, including the EPHB2 receptor. Notably, the silencing of both E2F1 and EPHB2 recapitulates TAZ-AS202 silencing cellular phenotype, indicating that they are essential mediators of its activity. Overall, this work unveiled a new regulatory mechanism that, by increasing E2F1 protein, modifies the non-small cell lung cancer cells transcriptional program, leading to enhanced aggressiveness features. The TAZ-AS202/E2F1/EPHB2 axis may be the target for new therapeutic strategies.

Lysin (K)-specific demethylase 1 inhibition enhances proteasome inhibitor response and overcomes drug resistance in multiple myeloma.

BACKGROUND: Multiple myeloma (MM) is an incurable plasma cell malignancy, accounting for approximately 1% of all cancers. Despite recent advances in the treatment of MM, due to the introduction of proteasome inhibitors (PIs) such as bortezomib (BTZ) and carfilzomib (CFZ), relapses and disease progression remain common. Therefore, a major challenge is the development of novel therapeutic approaches to overcome drug resistance, improve patient outcomes, and broaden PIs applicability to other pathologies. METHODS: We performed genetic and drug screens to identify new synthetic lethal partners to PIs, and validated candidates in PI-sensitive and -resistant MM cells. We also tested best synthetic lethal interactions in other B-cell malignancies, such as mantle cell, Burkitt's and diffuse large B-cell lymphomas. We evaluated the toxicity of combination treatments in normal peripheral blood mononuclear cells (PBMCs) and bone marrow stromal cells (BMSCs). We confirmed the combo treatment' synergistic effects ex vivo in primary CD138+ cells from MM patients, and in different MM xenograft models. We exploited RNA-sequencing and Reverse-Phase Protein Arrays (RPPA) to investigate the molecular mechanisms of the synergy. RESULTS: We identified lysine (K)-specific demethylase 1 (LSD1) as a top candidate whose inhibition can synergize with CFZ treatment. LSD1 silencing enhanced CFZ sensitivity in both PI-resistant and -sensitive MM cells, resulting in increased tumor cell death. Several LSD1 inhibitors (SP2509, SP2577, and CC-90011) triggered synergistic cytotoxicity in combination with different PIs in MM and other B-cell neoplasms. CFZ/SP2509 treatment exhibited a favorable cytotoxicity profile toward PBMCs and BMSCs. We confirmed the clinical potential of LSD1-proteasome inhibition in primary CD138+ cells of MM patients, and in MM xenograft models, leading to the inhibition of tumor progression. DNA damage response (DDR) and proliferation machinery were the most affected pathways by CFZ/SP2509 combo treatment, responsible for the anti-tumoral effects. CONCLUSIONS: The present study preclinically demonstrated that LSD1 inhibition could provide a valuable strategy to enhance PI sensitivity and overcome drug resistance in MM patients and that this combination might be exploited for the treatment of other B-cell malignancies, thus extending the therapeutic impact of the project.

Spatially resolved, high-dimensional transcriptomics sorts out the evolution of biphasic malignant pleural mesothelioma: new paradigms for immunotherapy.

BACKGROUND: Malignant Pleural Mesothelioma (MPM) is a dreadful disease escaping the classical genetic model of cancer evolution and characterized by wide heterogeneity and transcriptional plasticity. Clinical evolution of MPM is marked by a progressive transdifferentiation that converts well differentiated epithelioid (E) cells into undifferentiated and pleomorphic sarcomatoid (S) phenotypes. Catching the way this transition takes place is necessary to understand how MPM develops and progresses and it is mandatory to improve patients' management and life expectancy. Bulk transcriptomic approaches, while providing a significant overview, failed to resolve the timing of this evolution and to identify the hierarchy of molecular events through which this transition takes place. METHODS: We applied a spatially resolved, high-dimensional transcriptomic approach to study MPM morphological evolution. 139 regions across 8 biphasic MPMs (B-MPMs) were profiled using the GeoMx™Digital Spatial Profiler to reconstruct the positional context of transcriptional activities and the spatial topology of MPM cells interactions. Validation was conducted on an independent large cohort of 84 MPMs by targeted digital barcoding analysis. RESULTS: Our results demonstrated the existence of a complex circular ecosystem in which, within a strong asbestos-driven inflammatory environment, MPM and immune cells affect each other to support S-transdifferentiation. We also showed that TGFB1 polarized M2-Tumor Associated Macrophages foster immune evasion and that TGFB1 expression correlates with reduced survival probability. CONCLUSIONS: Besides providing crucial insights into the multidimensional interactions governing MPM clinical evolution, these results open new perspectives to improve the use of immunotherapy in this disease.

Ex vivo mapping of enhancer networks that define the transcriptional program driving melanoma metastasis.

Mortality from vmelanoma is associated with metastatic disease, but the mechanisms leading to spreading of the cancer cells remain obscure. Spatial profiling revealed that melanoma is characterized by a high degree of heterogeneity, which is established by the ability of melanoma cells to switch between different phenotypical stages. This plasticity, likely a heritage from embryonic pathways, accounts for a relevant part of the metastatic potential of these lesions, and requires the rapid and efficient reorganization of the transcriptional landscape of melanoma cells. A large part of the non-coding genome cooperates to control gene expression, specifically through the activity of enhancers (ENHs). In this study, we aimed to identify ex vivo the network of active ENHs and to outline their cooperative interactions in supporting transcriptional adaptation during melanoma metastatic progression. We conducted a genome-wide analysis to map active ENHs distribution in a retrospective cohort of 39 melanoma patients, comparing the profiles obtained in primary (N = 19) and metastatic (N = 20) melanoma lesions. Unsupervised clustering showed that the profile for acetylated histone H3 at lysine 27 (H3K27ac) efficiently segregates lesions into three different clusters corresponding to progressive stages of the disease. We reconstructed the map of super-ENHs (SEs) and cooperative ENHs that associate with metastatic progression in melanoma, which showed that cooperation among regulatory elements is a mandatory requirement for transcriptional plasticity. We also showed that these elements carry out specialized and non-redundant functions, and indicated the existence of a hierarchical organization, with SEs on top as masterminds of the entire transcriptional program and classical ENHs as executors. By providing an innovative vision of how the chromatin landscape of melanoma works during metastatic spreading, our data also point out the need to integrate functional profiling in the analysis of cancer lesions to increase definition and improve interpretation of tumor heterogeneity.

Medullary Thyroid Carcinomas Classified According to the International Medullary Carcinoma Grading System and a Surveillance, Epidemiology, and End Results-Based Metastatic Risk Score: A Correlation With Genetic Profile and Angioinvasion.

Due to the lack of a standardized tool for risk-based stratification, the International Medullary Carcinoma Grading System (IMTCGS) has been proposed for medullary thyroid carcinomas (MTCs) based on necrosis, mitosis, and Ki67. Similarly, a risk stratification study using the Surveillance, Epidemiology, and End Results (SEER) database highlighted significant differences in MTCs in terms of clinical-pathological variables. We aimed to validate both the IMTCGS and SEER-based risk table on 66 MTC cases, with special attention to angioinvasion and the genetic profile. We found a significant association between the IMTCGS and survival because patients classified as high-grade had a lower event-free survival probability. Angioinvasion was also found to be significantly correlated with metastasis and death. Applying the SEER-based risk table, patients classified either as intermediate- or high-risk had a lower survival rate than low-risk patients. In addition, high-grade IMTCGS cases had a higher average SEER-based risk score than low-grade cases. Moreover, when we explored angioinvasion in correlation with the SEER-based risk table, patients with angioinvasion had a higher average SEER-based score than patients without angioinvasion. Deep sequencing analysis found that 10 out of 20 genes frequently mutated in MTCs belonged to a specific functional class, namely chromatin organization, and function, which may be responsible for the MTC heterogeneity. In addition, the genetic signature identified 3 main clusters; cases belonging to cluster II displayed a significantly higher number of mutations and higher tumor mutational burden, suggesting increased genetic instability, but cluster I was associated with the highest number of negative events. In conclusion, we confirmed the prognostic performance of the IMTCGS and SEER-based risk score, showing that patients classified as high-grade had a lower event-free survival probability. We also underline that angioinvasion has a significant prognostic role, which has not been incorporated in previous risk scores.

Long non-coding RNA mitophagy and ALK-negative anaplastic lymphoma-associated transcript: a novel regulator of mitophagy in T-cell lymphoma.

Long non-coding RNA (lncRNA) are emerging as powerful and versatile regulators of transcriptional programs and distinctive biomarkers of progression of T-cell lymphoma. Their role in the aggressive anaplastic lymphoma kinase-negative (ALK-) subtype of anaplastic large cell lymphoma (ALCL) has been elucidated only in part. Starting from our previously identified ALCL-associated lncRNA signature and performing digital gene expression profiling of a retrospective cohort of ALCL, we defined an 11 lncRNA signature able to discriminate among ALCL subtypes. We selected a not previously characterized lncRNA, MTAAT, with preferential expression in ALK- ALCL, for molecular and functional studies. We demonstrated that lncRNA MTAAT contributes to an aberrant mitochondrial turnover restraining mitophagy and promoting cellular proliferation. Functionally, lncRNA MTAAT acts as a repressor of a set of genes related to mitochondrial quality control via chromatin reorganization. Collectively, our work demonstrates the transcriptional role of lncRNA MTAAT in orchestrating a complex transcriptional program sustaining the progression of ALK- ALCL.

An Innovative Drug Repurposing Approach to Restrain Endometrial Cancer Metastatization.

BACKGROUND: Endometrial cancer (EC) is the most common gynecologic tumor and the world's fourth most common cancer in women. Most patients respond to first-line treatments and have a low risk of recurrence, but refractory patients, and those with metastatic cancer at diagnosis, remain with no treatment options. Drug repurposing aims to discover new clinical indications for existing drugs with known safety profiles. It provides ready-to-use new therapeutic options for highly aggressive tumors for which standard protocols are ineffective, such as high-risk EC. METHODS: Here, we aimed at defining new therapeutic opportunities for high-risk EC using an innovative and integrated computational drug repurposing approach. RESULTS: We compared gene-expression profiles, from publicly available databases, of metastatic and non-metastatic EC patients being metastatization the most severe feature of EC aggressiveness. A comprehensive analysis of transcriptomic data through a two-arm approach was applied to obtain a robust prediction of drug candidates. CONCLUSIONS: Some of the identified therapeutic agents are already successfully used in clinical practice to treat other types of tumors. This highlights the potential to repurpose them for EC and, therefore, the reliability of the proposed approach.

Endogenous Extracellular Matrix Regulates the Response of Osteosarcoma 3D Spheroids to Doxorubicin.

The extracellular matrix (ECM) modulates cell behavior, shape, and viability as well as mechanical properties. In recent years, ECM disregulation and aberrant remodeling has gained considerable attention in cancer targeting and prevention since it may stimulate tumorigenesis and metastasis. Here, we developed an in vitro model that aims at mimicking the in vivo tumor microenvironment by recapitulating the interactions between osteosarcoma (OS) cells and ECM with respect to cancer progression. We long-term cultured 3D OS spheroids made of metastatic or non-metastatic OS cells mixed with mesenchymal stromal cells (MSCs); confirmed the deposition of ECM proteins such as Type I collagen, Type III collagen, and fibronectin by the stromal component at the interface between tumor cells and MSCs; and found that ECM secretion is inhibited by a neutralizing anti-IL-6 antibody, suggesting a new role of this cytokine in OS ECM deposition. Most importantly, we showed that the cytotoxic effect of doxorubicin is reduced by the presence of Type I collagen. We thus conclude that ECM protein deposition is crucial for modelling and studying drug response. Our results also suggest that targeting ECM proteins might improve the outcome of a subset of chemoresistant tumors.

Adding pieces to the puzzle of differentiated-to-anaplastic thyroid cancer evolution: the oncogene E2F7.

Anaplastic Thyroid Cancer (ATC) is the most aggressive and de-differentiated subtype of thyroid cancer. Many studies hypothesized that ATC derives from Differentiated Thyroid Carcinoma (DTC) through a de-differentiation process triggered by specific molecular events still largely unknown. E2F7 is an atypical member of the E2F family. Known as cell cycle inhibitor and keeper of genomic stability, in specific contexts its function is oncogenic, guiding cancer progression. We performed a meta-analysis on 279 gene expression profiles, from 8 Gene Expression Omnibus patient samples datasets, to explore the causal relationship between DTC and ATC. We defined 3 specific gene signatures describing the evolution from normal thyroid tissue to DTC and ATC and validated them in a cohort of human surgically resected ATCs collected in our Institution. We identified E2F7 as a key player in the DTC-ATC transition and showed in vitro that its down-regulation reduced ATC cells' aggressiveness features. RNA-seq and ChIP-seq profiling allowed the identification of the E2F7 specific gene program, which is mainly related to cell cycle progression and DNA repair ability. Overall, this study identified a signature describing DTC de-differentiation toward ATC subtype and unveiled an E2F7-dependent transcriptional program supporting this process.

BETi enhance ATGL expression and its lipase activity to exert their antitumoral effects in triple-negative breast cancer (TNBC) cells.

BACKGROUND: Triple-Negative Breast Cancer (TNBC) is a subtype of breast cancer that differs from other types of breast cancers in the faster spread and worse outcome. TNBC presented limited treatment options. BET (Bromodomain and extra-terminal domain) proteins are epigenetic readers that control the expression of different oncogenic proteins, and their inhibition (BETi) is considered a promising anti-cancer strategy. Recent evidence demonstrated the involvement of BET proteins in regulation of metabolic processes. METHODS: MDA-MB231 cells treated with JQ1 followed by RNA-sequencing analysis showed altered expression of lipid metabolic genes; among these, we focused on ATGL, a lipase required for efficient mobilization of triglyceride. Different in vitro approaches were performed to validate the RNA-sequencing data (qRT-PCR, immunofluorescence and flow cytometry). NMR (Nuclear Magnetic Resonance) was used to analyze the lipid reprogramming upon treatment. ATGL expression was determined by immunoblot and qRT-PCR, and the impact of ATGL function or protein knockdown, alone and in combination with BETi, was assessed by analyzing cell proliferation, mitochondrial function, and metabolic activity in TNBC and non-TNBC cells culture models. RESULTS: TNBC cells treated with two BETi markedly increased ATGL expression and lipolytic function and decreased intracellular lipid content in a dose and time-dependent manner. The intracellular composition of fatty acids (FAs) after BETi treatment reflected a significant reduction in neutral lipids. The short-chain FA propionate entered directly into the mitochondria mimicking ATGL activity. ATGL KD (knockdown) modulated the levels of SOD1 and CPT1a decreasing ROS and helped to downregulate the expression of mitochondrial ß-oxidation genes in favor of the upregulation of glycolytic markers. The enhanced glycolysis is reflected by the increased of the mitochondrial activity (MTT assay). Finally, we found that after BETi treatment, the FoxO1 protein is upregulated and binds to the PNPLA2 promoter leading to the induction of ATGL. However, FoxO1 only partially prompted the induction of ATGL expression by BETi. CONCLUSIONS: The anti-proliferative effect achieved by BETi is helped by ATGL mediating lipolysis. This study showed that BETi altered the mitochondrial dynamics taking advantage of ATGL function to induce cell cycle arrest and cell death. Schematic representation of BETi mechanism of action on ATGL in TNBC cells. BETi induce the expression of FoxO1 and ATGL, lowering the expression of G0G2, leading to a switch in metabolic status. The induced expression of ATGL leads to increased lipolysis and a decrease in lipid droplet content and bioavailability of neutral lipid. At the same time, the mitochondria are enriched with fatty acids. This cellular status inhibits cell proliferation and increases ROS production and mitochondrial stress. Interfering for ATGL expression, the oxidative phenotypic status mildly reverted to a glycolytic status where neutral lipids are stored into lipid droplets with a consequent reduction of oxidative stress in the mitochondrial.