ALDH1A1 confers resistance to RAF/MEK inhibitors in melanoma cells by maintaining stemness phenotype and activating PI3K/AKT signaling.

The mitogen-activated protein kinase (MAPK/ERK) pathway is pivotal in controlling the proliferation and survival of melanoma cells. Several mutations, including those in BRAF, exhibit an oncogenic effect leading to increased cellular proliferation. As a result, the combination therapy of a MEK inhibitor with a BRAF inhibitor demonstrated higher efficacy and lower toxicity than BRAF inhibitor alone. This combination has become the preferred standard of care for tumors driven by BRAF mutations. Aldehyde dehydrogenase 1A1 (ALDH1A1) is a known marker of stemness involved in drug resistance in several type of tumors, including melanoma. This study demonstrates that melanoma cells overexpressing ALDH1A1 displayed resistance to vemurafenib and trametinib through the activation of PI3K/AKT signaling instead of MAPK axis. Inhibition of PI3K/AKT signaling partially rescued sensitivity to the drugs. Consistently, pharmacological inhibition of ALDH1A1 activity downregulated the activation of AKT and partially recovered responsiveness to vemurafenib and trametinib. We propose ALDH1A1 as a new potential target for treating melanoma resistant to MAPK/ERK inhibitors.

Validity of Italian administrative healthcare data in describing the real-world utilization of infusive antineoplastic drugs: the study case of rituximab use in patients treated at the University Hospital of Siena for onco-haematological indications.

Introduction: Italian administrative healthcare databases are frequently used for studies on real-world drug utilization. However, there is currently a lack of evidence on the accuracy of administrative data in describing the use of infusive antineoplastics. In this study, we used rituximab as a case study to investigate the validity of the regional administrative healthcare database of Tuscany (RAD) in describing the utilization of infusive antineoplastics. Methods: We identified patients aged 18 years or older who had received ≥1 rituximab administration between 2011 and 2014 in the onco-haematology ward of the University Hospital of Siena. We retrieved this information from the Hospital Pharmacy Database (HPD-UHS) and linked the person-level information to RAD. Patients who had received ≥1dispensing of rituximab, single administration episodes, and patients treated for non-Hodgkin Lymphoma (nHL) or Chronic Lymphocytic Leukemia (CLL) were identified in RAD and validated using HPD-UHS as the reference standard. We identified the indications of use using algorithms based on diagnostic codes (ICD9CM codes, nHL=200*, 202*; CLL=204.1). We tested 22 algorithms of different complexity for each indication of use and calculated sensitivity and positive predictive value (PPV), with 95% confidence intervals (95%CI), as measures of validity. Results: According to HPD-UHS, 307 patients received rituximab for nHL (N=174), CLL (N=21), or other unspecified indications (N=112) in the onco-haematology ward of the University Hospital of Siena. We identified 295 rituximab users in RAD (sensitivity=96.1%), but PPV could not be assessed due to missing information in RAD on dispensing hospital wards. We identified individual rituximab administration episodes with sensitivity=78.6% [95%CI: 76.4-80.6] and PPV=87.6% [95%CI: 86.1-89.2]. Sensitivity of algorithms tested for identifying nHL and CLL ranged from 87.7% to 91.9% for nHL and from 52.4% to 82.7% for CLL. PPV ranged from 64.7% to 66.1% for nHL and from 32.4% to 37.5% for CLL. Discussion: Our findings suggest that RAD is a very sensitive source of information for identifying patients who received rituximab for onco-haematological indications. Single administration episodes were identified with good-to-high accuracy. Patients receiving rituximab for nHL were identified with high sensitivity and acceptable PPV, while the validity for CLL was suboptimal.

Uncovering Knowledge Gaps in the Safety Profile of Antiangiogenic Drugs in Cancer Patients: Insights from Spontaneous Reporting Systems Studies.

Global repositories of postmarketing safety reports improve understanding of real-life drug toxicities, often not observed in clinical trials. The aim of this scoping review was to map the evidence from spontaneous reporting systems studies (SRSs) of antiangiogenic drugs (AADs) in cancer patients and highlight if the found disproportionality signals of adverse events (AEs) were validated and thus mentioned in the respective Summary of product Characteristics (SmPC). This scoping review was conducted according to PRISMA guidelines for scoping reviews. A knowledge gap on the safety of AADs was found: firstly, several cardiovascular AEs were not mentioned in the SmPCs and no pharmacovigilance studies were conducted despite the well-known safety concerns about these drugs on the cardiovascular system. Second, a disproportionality signal (not validated through causality assessment) of pericardial disease was found in the literature for axitinib with no mention in SmPC of the drug. Despite the exclusion of pharmacoepidemiological studies, we believe that this scoping review, which focuses on an entire class of drugs, could be considered as a novel approach to highlight possible safety concerns of drugs and as a guide for the conduction of a target postmarketing surveillance on AADs.

Risk of Intraocular Pressure Increase With Intravitreal Injections of Vascular Endothelial Growth Factor Inhibitors: A Cohort Study.

PURPOSE: Intraocular pressure increase (IOPi) after intravitreal injections of vascular endothelial growth factor inhibitors (VEGFis) might be different among different VEGFis (bevacizumab, aflibercept, ranibizumab). The purpose of this study was to evaluate the risk of IOPi among new users of bevacizumab, ranibizumab, and aflibercept in nondiabetic patients in Tuscany, Italy. DESIGN: Retrospective cohort study. METHODS: Tuscan regional administrative database was used to identify subjects with a first VEGFi intravitreal injection between 2011 and 2020, followed to first incidence of IOPi. Diabetic subjects, those with pre-existing IOPi, or previous use of dexamethasone implants were excluded. Multivariable Cox regression analyses (intention-to-treat and as treated) were conducted to evaluate risk of IOPi among aflibercept, bevacizumab, and ranibizumab, adjusting for potential confounding variables. IOPi was defined as the first record of International Classification of Diseases, Ninth Revision (ICD-9-CM) code 365 or use of 2 glaucoma drugs dispensations within 180 days of each other. RESULTS: We identified 6585 new users of VEGFis: 1749 aflibercept, 1112 bevacizumab, and 3724 ranibizumab. Women made up 60% of the cohort, with a mean age of 73.6 years. In the intention-to-treat analysis, the adjusted hazard ratio (HR) for incident IOPi, compared with aflibercept, was higher for bevacizumab (HR = 2.20, 95% CI = 1.64-2.95) and ranibizumab users (HR = 1.88, 95% CI = 1.46-2.42), respectively. The HRs remained robust after exclusion of patients with proxy of retinal vascular occlusion. As treated analysis confirmed such results (bevacizumab: HR = 3.76, 95% CI = 2.30-6.17; ranibizumab: HR = 2.49, 95% CI = 1.62-3.82). CONCLUSIONS: This study found an increased risk of IOPi among nondiabetic patients with ranibizumab and bevacizumab compared with aflibercept. Future studies are needed to validate these findings.

Safety of Anti-Angiogenic Drugs in Pediatric Patients with Solid Tumors: A Systematic Review and Meta-Analysis.

Cancer is a clinical condition that can benefit from anti-angiogenic drugs (AADs). Given the low prevalence and the heterogeneity of childhood cancers, information about the safety of these drugs in pediatric patients is partially assessed. The aim of this study was to evaluate the safety of AADs in pediatric patients with solid tumors. Clinical trials and observational studies were searched in PubMed, ISI Web of Science, and ClinicalTrials database For each included study, adverse events (AEs) were extracted. A meta-analysis was conducted by pooling proportions of AEs using a random intercept logistic regression model. Seventy studies were retrieved. Most part were clinical trials (55 out of 70), and only fifteen observational studies were found. Overall, proportion of serious and non-serious AEs of AADs used as monotherapy was 46% and 89%, respectively. Proportions of serious AEs varied among drugs: sunitinib, 79%; lenvatinib, 64%; sorafenib, 48%; ramucirumab, 41%; pazopanib, 30%; and vandetanib, 27%. A higher proportion of non-serious hematological AEs was found in the patients receiving pazopanib with respect to sunitinib and lenvatinib. The safety profile of AADs has been extensively investigated for mostly drugs in phase I and II trials and is limited to acute toxicities. Overall, one out of two patients using AAD drugs in monotherapy experienced a serious AE despite proportions varied per single drugs. When AADs were combined with standard chemotherapy, the proportion of AEs varied in relation to the single combinations.

Development and validation of a case-finding algorithm for the identification of non-small cell lung cancers in a region-wide Italian pathology registry.

PURPOSE: To develop and validate a case-finding algorithm for the identification of Non-Small Cell Lung Cancer (NSCLC) cases in a region-wide Italian pathology registry (PR). MATERIALS AND METHODS: Data collected between 2009 and 2017 in the PR and the Pharmacy Database of the University Hospital of Siena and the PR of Tuscany region were used. A NSCLC-identification algorithm based on free-text keywords and SNOMED morphology and topography codes was designed and tested on data from Siena: indication for drug use (i.e. NSCLC) was the reference standard for sensitivity (SE); positive predictive value (PPV) was estimated through manual review. Algorithm modifications were then tested to improve algorithm performance: PPV was calculated against validated dataset from PR of Siena; a range of SE [min-max] was estimated in PR of Tuscany using analytical formulae that assumed NSCLC incidence equal either to 80% or 90% of overall lung cancer incidence recorded in Tuscany. The algorithm modification with the best performance was chosen as the final version of the algorithm. A random sample of 200 cases was extracted from the PR of Tuscany for manual review. RESULTS: The first version of the algorithm showed a PPV of 74.7% and SE of 79% in PR of Siena. The final version of the algorithm had a SE in PR of Tuscany that grew with calendar time (2009 = [24.7%-28%]; 2017 = [57.9%-65.1%]) and a PPV of 93%. CONCLUSIONS: The final NSCLC-finding algorithm showed with very high PPV. SE was in line with the expected contribution of PR to overall cases captured in the regional Cancer Registry, with a trend of increase over calendar time. Given the promising algorithm validity and the wide use of SNOMED terminology in electronic pathology records, the proposed algorithm is expected to be easily adapted to other electronic databases for (pharmaco)epidemiology purposes.

ALDH1A1 overexpression in melanoma cells promotes tumor angiogenesis by activating the IL­8/Notch signaling cascade.

ALDH1A1 is a cytosolic enzyme upregulated in tumor cells, involved in detoxifying cells from reactive aldehydes and in acquiring resistance to chemotherapeutic drugs. Its expression correlates with poor clinical outcomes in a number of cancers, including melanoma. The present study hypothesized that the increased ALDH1A1 expression and activity upregulated the release of proangiogenic factors from melanoma cells, which regulate angiogenic features in endothelial cells (ECs) through a rearrangement of the Notch pathway. In vivo, when subcutaneously implanted in immunodeficient mice, ALDH1A1 overexpressing melanoma cells displayed a higher microvessel density. In a 3D multicellular system, obtained co­culturing melanoma cancer cells with stromal cells, including ECs, melanoma ALDH1A1 overexpression induced the recruitment of ECs into the core of the tumorspheres. By using a genes array, overexpression of ALDH1A1 in tumor cells also promoted modulation of Notch cascade gene expression in ECs, suggesting an interaction between tumor cells and ECs mediated by enrichment of angiogenic factors in the tumor microenvironment. To confirm this hypothesis, inactivation of ALDH1A1 by the pharmacological inhibitor CM037 significantly affected the release of angiogenic factors, including IL­8, from melanoma cells. High levels of ALDH1A1, through the retinoic acid pathway, regulated the activation of NF­kB­p65 and IL­8. Further, in a 2D co­culture system, the addition of an IL­8 neutralizing antibody to ECs co­cultured with melanoma cells forced to express ALDH1A1 dampened endothelial angiogenic features, both at the molecular (in terms of gene and protein expression of mediators of the Notch pathway) and at the functional level (proliferation, scratch assay, tube formation and permeability). In conclusion, these findings demonstrated the existence of a link between melanoma ALDH1A1 expression and EC Notch signaling modification that results in a pro­angiogenic phenotype. Based on the crucial role of ALDH1A1 in melanoma control of the tumor microenvironment, the enzyme seems a promising target for the development of novel drugs able to interrupt the cross­talk between cancer (stem) cells and endothelial cells.

First-Line Pharmacotherapies and Survival among Patients Diagnosed with Non-Resectable NSCLC: A Real-Life Setting Study with Gender Prospective.

(1) Purpose: To describe first-line pharmacotherapy and overall survival in non-resectable non-small cell lung cancer (nrNSCLC) patients by gender. (2) Methods: Incident cases of nrNSCLC recorded between 2009 and 2019 (cohort entry) in the pathology registry of the regional administrative healthcare database of Tuscany were identified. Records of antineoplastic therapies delivered up to 4 months following cohort entry were classified as chemotherapy, target therapies, immunotherapies, and undefined monoclonal antibodies. First-line treatment and survival of patients receiving drug treatment was described. Analyses were stratified according to histology, gender, and cohort entry year. (3) Results: 4393 incident cases of nrNSCLC were included. Women with non-squamous-NSCLC received target-therapy more frequently than men (14.9% vs. 6.5%). Immunotherapy incidence of use varied between 3.8% (2017) and 9.1% (2019). The 2-year survival rate increased over time: for non-squamous-NSCLC, it was 22.3% (2009-2011) and 30.6% (2018-2019), while for squamous-NSCLC, it was 13.5% and 22.5%, respectively. After multivariate analysis, a low reduction in mortality risk in 2018-2019 vs. 2009-2011 was found (non-squamous: HR: 0.95 CI95%: 0.92-0.98; squamous: HR: 0.94 CI95%: 0.90-0.98). Among non-squamous NSCLC, median survival was longer in women than in men (389 vs. 276 days). (4) Conclusion: In light of sex-related biomolecular differences, among non-squamous NSCLC, women received target-therapy more frequently than men. Survival seemed to slightly improve over the study period for both histologies, despite a poor reduction in mortality risk was still observed.

Molecular Mechanisms of Resistance to Anti-Angiogenic Drugs.

The problem of drug resistance in cancer patients has been well in mind from the beginning of modern medicine and oncology treatments with the so called conventional cytotoxic therapy. With the advent of target therapy against tumor angiogenesis and in particular against the vascular endothelial growth factor (VEGF)/VEGF receptor system, researchers thought that resistance could be no more a problem, since the low pattern of proliferation displayed by endothelial cells. However, beside the efficacy demonstrated by antiangiogenic drugs, resistance during prolonged drug treatments appears as a limiting feature. Nowadays, various mechanisms of resistance to antiangiogenic therapeutics have been discovered, either innate and depending on the host, or acquired by the tumor cells, especially as a consequence of induced hypoxia by antiangiogenic drugs and the redundancy of proangiogenic factors in the tumor microenvironment, and other forms of tumor neovascularization, than sprouting angiogenesis. Here, we have reviewed the preclinical and clinical evidence for mechanisms of resistance to antiangiogenic drugs reported so far. The knowledge of the mechanisms underneath antiangiogenic drug resistance could be of help in the choice of the more appropriate drug, the development of novel therapeutic strategies, the design of proper drug combination protocols or new formulations of antiangiogenic strategies.

Real-World Utilization of Target- and Immunotherapies for Lung Cancer: A Scoping Review of Studies Based on Routinely Collected Electronic Healthcare Data.

Routinely collected electronic healthcare data (rcEHD) have a tremendous potential for enriching pre-marketing evidence on target- and immunotherapies used to treat lung cancer (LC). A scoping review was performed to provide a structured overview of available rcEHD-based studies on this topic and to support the execution of future research by facilitating access to pertinent literature both for study design and benchmarking. Eligible studies published between 2016 and 2020 in PubMed and ISI Web of Science were searched. Data source and study characteristics, as well as evidence on drug utilization and survival were extracted. Thirty-two studies were included. Twenty-six studies used North American data, while three used European data only. Thirteen studies linked ≥1 data source types among administrative/claims data, cancer registries and medical/health records. Twenty-nine studies retrieved cancer-related information from medical records/cancer registries and 31 studies retrieved information on drug utilization or survival from medical records or administrative/claim data. Most part of studies concerned non-small-cell-LC patients (29 out of 32) while none focused on small-cell-LC. Study cohorts ranged between 85 to 81,983 patients. Only two studies described first-line utilization of immunotherapies. Results from this review will serve as a starting point for the execution of future rcEHD-based studies on innovative LC pharmacotherapies.

Repurposing of drugs for triple negative breast cancer: an overview.

Breast cancer (BC) is the most frequent cancer among women in the world and it remains a leading cause of cancer death in women globally. Among BCs, triple negative breast cancer (TNBC) is the most aggressive, and for its histochemical and molecular characteristics is also the one whose therapeutic opportunities are most limited. The REpurposing Drugs in Oncology (ReDO) project investigates the potential use of off patent non-cancer drugs as sources of new cancer therapies. Repurposing of old non-cancer drugs, clinically approved, off patent and with known targets into oncological indications, offers potentially cheaper effective and safe drugs. In line with this project, this article describes a comprehensive overview of preclinical or clinical evidence of drugs included in the ReDO database and/or PubMed for repurposing as anticancer drugs into TNBC therapeutic treatments.

Real word evidence on rituximab utilization: Combining administrative and hospital-pharmacy data.

PURPOSE: To describe patterns of utilization, survival and infectious events in patients treated with rituximab at the University Hospital of Siena (UHS) to explore the feasibility of combining routinely collected administrative and hospital-pharmacy data for examining the real-world use of intravenous antineoplastic drugs. METHODS: A retrospective, longitudinal cohort study was conducted using data from the Hospital Pharmacy of Siena (HPS) and the Regional Administrative Database of Tuscany (RAD). Patients aged ≥18 years with ≥1 rituximab administration recorded between January 2012 and June 2016 were identified in the HPS database. Anonymized patient-level data were linked to RAD. Rituximab utilization during the first year of treatment was described using HPS. Hospital diagnoses of adverse infectious events that occurred during the first year of follow-up and four-year survival were observed using RAD. RESULTS: A total of 311 new users of rituximab were identified: 264 patients received rituximab for non-Hodgkin's lymphoma (NHL) and 47 were treated for chronic lymphocytic leukemia (CLL). Among new users with one complete year of follow-up (n = 203) over 95% received rituximab as the first-line treatment, and approximately 70% of them received 5-8 doses. No patient in the CLL group received >8 administrations. Four-year survival was approximately 70% in both CLL and NHL patients. Sepsis was the most frequent infectious event observed (5.1%). CONCLUSION: HPS and RAD provided complementary information on rituximab utilization, demonstrating their potential for future pharmacoepidemiological studies on antineoplastic medications administered in the Italian hospital setting. Overall, this general description of the real-world utilization of rituximab in patients treated for NHL and CLL at UHS was in line with treatment guidelines and current knowledge on the rituximab safety profile.

How to conjugate the stemness marker ALDH1A1 with tumor angiogenesis, progression, and drug resistance.

Cancer is the second leading cause of death worldwide. The survival of cancer patients depends on the efficacy of therapies and the development of resistance. There are many mechanisms involved in the acquisition of drug resistance by cancer cells, including the acquisition of stem-like features. Cancer stem cells (CSCs) represent a major source of tumor progression and treatment resistance. CSCs are a subpopulation of cancer cells having the abilities to self-renew and form spheres in vitro. Aldehyde dehydrogenase 1A1 (ALDH1A1) is a cytosolic enzyme involved in the detoxification of cells from toxic aldehydes and belongs to the ALDH family. High ALDH1A1 activity is closely related to stemness phenotype of several tumors, possibly contributing to cancer progression and diffusion in the body. We have documented the contribution of ALDH1A1 in tumor angiogenesis in breast cancer cells by the activation of hypoxia inducible factor-1α and vascular endothelial growth factor signaling. This review discusses the involvement of ALDH1A1 in the development of different hallmarks of cancer to propose it as a novel putative target for cancer treatment to achieve better outcome. Here, we analyze the involvement of ALDH1A1 in the acquisition of stemness phenotype in tumor cells, the regulation of tumor angiogenesis and metastases, and the acquisition of anticancer drug resistance and immune evasion.

Targeting endothelial-to-mesenchymal transition: the protective role of hydroxytyrosol sulfate metabolite.

PURPOSE: Endothelial-to-mesenchymal transition (EndMT) plays an important role in pathogenesis of a number of inflammatory diseases. Hydroxytyrosol (HT) and, particularly, its major plasma metabolite HT-3O sulfate (HT-3Os) are known olive oil antioxidant and anti-inflammatory polyphenols which exert benefits against vascular diseases by improving endothelial function. However, to date the HT-3Os role in EndMT is not well known. METHODS: To investigate the HT-3Os effects on EndMT in the inflamed endothelium, we used an in vitro model of endothelial dysfunction, challenging endothelial cells (EC), human umbilical EC (HUVEC) and human retinal EC (HREC) with Interleukin-1ß (IL-1ß), an inflammatory agent. HREC were used as a specific model to investigate HT-3Os effects on vascular retinal diseases. RESULTS: We found that IL-1ß treatment-induced EndMT phenotype in both cell models, also changing cell morphology. HT-3Os protected EC against IL-1ß effects, recovering cell morphology and phenotype. Mechanistically, HT-3Os targeting fibroblast growth factor receptor 1 FGFR1 expression and let-7 miRNA, controlled transforming growth factor beta (TGF-ß) signalling in EC, downregulating transcription factors expression (SNAI1 and ZEB2) and gene expression of late EndMT markers (FN1, VIM, NOTCH3, CNN1, MMP2 and MMP9). CONCLUSION: These results demonstrate that HT-3Os blunts pathological EndMT in inflamed EC, maintaining high let-7 miRNA expression and preventing activation of TGF-ß signalling.

ALDH3A1 Overexpression in Melanoma and Lung Tumors Drives Cancer Stem Cell Expansion, Impairing Immune Surveillance through Enhanced PD-L1 Output.

Melanoma and non-small-cell lung carcinoma (NSCLC) cell lines are characterized by an intrinsic population of cancer stem-like cells (CSC), and high expression of detoxifying isozymes, the aldehyde dehydrogenases (ALDHs), regulating the redox state. In this study, using melanoma and NSCLC cells, we demonstrate that ALDH3A1 isozyme overexpression and activity is closely associated with a highly aggressive mesenchymal and immunosuppressive profile. The contribution of ALDH3A1 to the stemness and immunogenic status of melanoma and NSCLC cells was evaluated by their ability to grow in 3D forming tumorspheres, and by the expression of markers for stemness, epithelial to mesenchymal transition (EMT), and inflammation. Furthermore, in specimens from melanoma and NSCLC patients, we investigated the expression of ALDH3A1, PD-L1, and cyclooxygenase-2 (COX-2) by immunohistochemistry. We show that cells engineered to overexpress the ALDH3A1 enzyme enriched the CSCs population in melanoma and NSCLC cultures, changing their transcriptome. In fact, we found increased expression of EMT markers, such as vimentin, fibronectin, and Zeb1, and of pro-inflammatory and immunosuppressive mediators, such as NFkB, prostaglandin E2, and interleukin-6 and -13. ALDH3A1 overexpression enhanced PD-L1 output in tumor cells and resulted in reduced proliferation of peripheral blood mononuclear cells when co-cultured with tumor cells. Furthermore, in tumor specimens from melanoma and NSCLC patients, ALDH3A1 expression was invariably correlated with PD-L1 and the pro-inflammatory marker COX-2. These findings link ALDH3A1 expression to tumor stemness, EMT and PD-L1 expression, and suggest that aldehyde detoxification is a redox metabolic pathway that tunes the immunological output of tumors.

mPGES-1 as a new target to overcome acquired resistance to gefitinib in non-small cell lung cancer cell lines.

Epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) as gefitinib are standard treatment of non-small cell lung cancer (NSCLC), but resistance often occurs. This study demonstrates that NSCLC cells resistant to gefitinib (GR cells) displayed a significantly higher microsomal prostaglandin E synthase-1 (mPGES-1) expression and activity than parental cells. Overexpression of mPGES-1/prostaglandin E-2 (PGE-2) signaling in GR cells was associated with acquisition of mesenchymal and stem-like cell properties, nuclear EGFR translocation and tolerance to cisplatin. mPGES-1 inhibition reduced mesenchymal and stem-like properties, and nuclear EGFR translocation in GR cells. Consistently, inhibition of mPGES-1 activity enhanced sensitivity to cisplatin and responsiveness to gefitinib in GR cells. We propose the mPGES-1/PGE-2 signaling as a potential target for treating aggressive and resistant lung cancers.

Correction to: Stemness marker ALDH1A1 promotes tumor angiogenesis via retinoic acid/HIF-1α/VEGF signalling in MCF-7 breast cancer cells.

ᅟ.

Stemness marker ALDH1A1 promotes tumor angiogenesis via retinoic acid/HIF-1α/VEGF signalling in MCF-7 breast cancer cells.

BACKGROUND: Aldehyde dehydrogenase 1A1 (ALDH1A1), a member of aldehyde dehydrogenase family, is a marker of stemness in breast cancer. During tumor progression cancer stem cells (CSCs) have been reported to secrete angiogenic factors to orchestrate the formation of pathological angiogenesis. This vasculature can represent the source of self-renewal of CSCs and the route for further tumor spreading. The aim of the present study has been to assess whether ALDH1A1 controls the output of angiogenic factors in breast cancer cells and regulates tumor angiogenesis in a panel of in vitro and in vivo models. METHODS: Stemness status of breast cancer cells was evaluated by the ability to form turmorspheres in vitro. A transwell system was used to assess the angiogenic features of human umbilical vein endothelial cells (HUVEC) when co-cultured with breast cancer cells MCF-7 harboring different levels of ALDH1A1. Under these conditions, we survey endothelial proliferation, migration, tube formation and permeability. Moreover, in vivo, MCF-7 xenografts in immunodeficient mice allow to evaluate blood flow, expression of angiogenic factors and microvascular density (MVD). RESULTS: In MCF-7 we observed that ALDH1A1 activity conferred stemness property and its expression correlated with an activation of angiogenic factors. In particular we observed a significant upregulation of hypoxia inducible factor-1α (HIF-1α) and proangiogenic factors, such as vascular endothelial growth factor (VEGF). High levels of ALDH1A1, through the retinoic acid pathway, were significantly associated with VEGF-mediated angiogenesis in vitro. Co-culture of HUVEC with ALDH1A1 expressing tumor cells promoted endothelial proliferation, migration, tube formation and permeability. Conversely, downregulation of ALDH1A1 in MCF-7 resulted in reduction of proangiogenic factor release/expression and impaired HUVEC angiogenic functions. In vivo, when subcutaneously implanted in immunodeficient mice, ALDH1A1 overexpressing breast tumor cells displayed a higher expression of VEGF and MVD. CONCLUSION: In breast tumors, ALDH1A1 expression primes a permissive microenvironment by promoting tumor angiogenesis via retinoic acid dependent mechanism. In conclusion, ALDH1A1 might be associated to progression and diffusion of breast cancer.

Bradykinin B2 Receptor Contributes to Inflammatory Responses in Human Endothelial Cells by the Transactivation of the Fibroblast Growth Factor Receptor FGFR-1.

Elevated levels of bradykinin (BK) and fibroblast growth factor-2 (FGF-2) have been implicated in the pathogenesis of inflammatory and angiogenic disorders. In angiogenesis, both stimuli induce a pro-inflammatory signature in endothelial cells, activating an autocrine/paracrine amplification loop that sustains the neovascularization process. Here we investigated the contribution of the FGF-2 pathway in the BK-mediated human endothelial cell permeability and migration, and the role of the B2 receptor (B2R) of BK in this cross-talk. BK (1 µM) upregulated the FGF-2 expression and promoted the FGF-2 signaling, both in human umbilical vein endothelial cells (HUVEC) and in retinal capillary endothelial cells (HREC) by the activation of Fibroblast growth factor receptor-1 (FGFR-1) and its downstream signaling (fibroblast growth factor receptor substrate: FRSα, extracellular signal⁻regulated kinases1/2: ERK1/2, and signal transducer and activator of transcription 3: STAT3 phosphorylation). FGFR-1 phosphorylation triggered by BK was c-Src mediated and independent from FGF-2 upregulation. Either HUVEC and HREC exposed to BK showed increased permeability, disassembly of adherens and tight-junction, and increased cell migration. B2R blockade by the selective antagonist, fasitibant, significantly inhibited FGF-2/FGFR-1 signaling, and in turn, BK-mediated endothelial cell permeability and migration. Similarly, the FGFR-1 inhibitor, SU5402, and the knock-down of the receptor prevented the BK/B2R inflammatory response in endothelial cells. In conclusion, this work demonstrates the existence of a BK/B2R/FGFR-1/FGF-2 axis in endothelial cells that might be implicated in propagation of angiogenic/inflammatory responses. A B2R blockade, by abolishing the initial BK stimulus, strongly attenuated FGFR-1-driven cell permeability and migration.

PGE2 mediates EGFR internalization and nuclear translocation via caveolin endocytosis promoting its transcriptional activity and proliferation in human NSCLC cells.

Prostaglandin E2 (PGE2) contributes to tumor progression by promoting cancer cell growth, invasion and by creating a favorable pro-tumor microenvironment. PGE2 has been reported to transactivate and internalize into the nucleus receptor tyrosine kinases such as Epidermal growth factor receptor (EGFR), thereby supporting tumor progression. Here we demonstrate that in non-small cell lung carcinoma (NSCLC) cells, PGE2 induces EGFR nuclear translocation via different dynamin-dependent endocytic pathways, promotes the formation of an EGFR-STAT3 complex, affects nuclear EGFR target gene expression and mediates tumor cell proliferation. Indeed, we find that PGE2 induces EGFR internalization and consequent nuclear import through Clathrin- and Caveolin-mediated endocytosis and through the interaction of EGFR with Importin ß1. Within the nucleus, EGFR forms a complex with STAT3, an event blocked by ablation of Clathrin Heavy Chain or Caveolin-1. The combination of EGF and PGE2 prolongs nuclear EGFR transcriptional activity manifested by the upregulation of CCND1, PTGS2, MYC and NOS2 mRNA levels and potentiates nuclear EGFR-induced NSCLC cell proliferation. Additionally, NSCLC patients with high expression of a nuclear EGFR gene signature display shorter survival times than those with low expression, thus showing a putative correlation between nuclear EGFR and poor prognosis in NSCLC. Together, our findings indicate a complex mechanism underlying PGE2-induced EGF/EGFR signaling and transcriptional control, which plays a key role in cancer progression.