Formation of an invasion-permissive matrix requires TGFß/SNAIL1-regulated alternative splicing of fibronectin.

BACKGROUND: As in most solid cancers, the emergence of cells with oncogenic mutations in the mammary epithelium alters the tissue homeostasis. Some soluble factors, such as TGFß, potently modify the behavior of healthy stromal cells. A subpopulation of cancer-associated fibroblasts expressing a TGFß target, the SNAIL1 transcription factor, display myofibroblastic abilities that rearrange the stromal architecture. Breast tumors with the presence of SNAIL1 in the stromal compartment, and with aligned extracellular fiber, are associated with poor survival prognoses. METHODS: We used deep RNA sequencing and biochemical techniques to study alternative splicing and human tumor databases to test for associations (correlation t-test) between SNAIL1 and fibronectin isoforms. Three-dimensional extracellular matrices generated from fibroblasts were used to study the mechanical properties and actions of the extracellular matrices on tumor cell and fibroblast behaviors. A metastatic mouse model of breast cancer was used to test the action of fibronectin isoforms on lung metastasis. RESULTS: In silico studies showed that SNAIL1 correlates with the expression of the extra domain A (EDA)-containing (EDA+) fibronectin in advanced human breast cancer and other types of epithelial cancers. In TGFß-activated fibroblasts, alternative splicing of fibronectin as well as of 500 other genes was modified by eliminating SNAIL1. Biochemical analyses demonstrated that SNAIL1 favors the inclusion of the EDA exon by modulating the activity of the SRSF1 splicing factor. Similar to Snai1 knockout fibroblasts, EDA- fibronectin fibroblasts produce an extracellular matrix  that does not sustain TGFß-induced fiber organization, rigidity, fibroblast activation, or tumor cell invasion. The presence of EDA+ fibronectin changes the action of metalloproteinases on fibronectin fibers. Critically, in an mouse orthotopic breast cancer model, the absence of the fibronectin EDA domain completely prevents lung metastasis. CONCLUSIONS: Our results support the requirement of EDA+ fibronectin in the generation of a metastasis permissive stromal architecture in breast cancers and its molecular control by SNAIL1. From a pharmacological point of view, specifically blocking EDA+ fibronectin deposition could be included in studies to reduce the formation of a pro-metastatic environment.

Effect of Fractional Carbon Dioxide vs Sham Laser on Sexual Function in Survivors of Breast Cancer Receiving Aromatase Inhibitors for Genitourinary Syndrome of Menopause: The LIGHT Randomized Clinical Trial.

Importance: Survivors of breast cancer present more severe symptoms of genitourinary syndrome of menopause (GSM) than patients without history of breast cancer. Recently, new treatments, such as vaginal laser therapy, have appeared, but evidence of their efficacy remains scarce. Objective: To assess the safety and efficacy of carbon dioxide (CO2) vs sham vaginal laser therapy after 6 months of follow-up in survivors of breast cancer with GSM receiving aromatase inhibitors. Design, Setting, and Participants: This prospective double-blind sham-controlled randomized clinical trial with two parallel study groups was performed during October 2020 to March 2022 in a tertiary referral hospital. Survivors of breast cancer using aromatase inhibitors were assessed for eligibility, and eligible patients were randomized into the 2 treatment groups. Follow-up was conducted at 6 months. Data were analyzed in July 2022. Interventions: All patients from both groups were instructed to use the first-line treatment (FLT) based on nonhormonal moisturizers and vaginal vibrator stimulation. Patients for each group were allocated to 5 monthly sessions of fractional CO2 laser therapy (CLT) or sham laser therapy (SLT). Main Outcomes and Measures: The primary outcome was sexual function, evaluated through Female Sexual Function Index (FSFI) score. Other subjective measures of efficacy included a visual analog scale of dyspareunia, vaginal pH, a Vaginal Health Index, quality of life (assessed via Short-Form 12), and body image (assessed with the Spanish Body Image Scale). Objective measures of efficacy included vaginal maturation index, vaginal epithelial elasticity (measured in Pascals) and vaginal epithelial thickness (measured in millimeters). Measures were assessed before and after the intervention. Tolerance (measured on a Likert scale), adverse effects, and estradiol levels were recorded. Results: Among 211 survivors of breast cancer assessed, 84 women were deemed eligible and 72 women (mean [SD] age, 52.6 [8.3] years) were randomized to CLT (35 participants) or SLT (37 participants) and analyzed. There were no statistically significant differences between groups at baseline. At 6 months, both groups showed improvement in FSFI (mean [SD] score at baseline vs 6 months: CLT, 14.8 [8.8] points vs 20.0 [9.5] points; SLT, 15.6 [7.0] points vs 23.5 [6.5] points), but there was no significant difference between CLT and SLT groups in the improvement of sexual function evaluated through the FSFI test overall (mean [SD] difference, 5.2 [1.5] points vs 7.9 [1.2] points; P = .15) or after excluding women who were not sexually active (mean [SD] difference, 2.9 [1.4] points vs 5.5 [1.1] points; P = .15). There were also no differences between improvement of the 2 groups at 6 months of follow-up in the other assessed subjective outcomes, including dyspareunia (mean [SD] difference, -4.3 [3.4] vs -4.5 [2.3]; P = .73), Vaginal Health Index (mean [SD] difference, 3.3 [4.1] vs 5.0 [4.5]; P = .17), body image (mean [SD] difference, -3.7 [4.5] vs -2.7 [4.8]; P = .35), and quality of life (mean [SD] difference, -0.3 [3.6] vs -0.7 [3.2]; P = .39). Similarly, there were no differences in improvements in objective outcomes, including vaginal pH (mean [SD] difference, -0.6 [0.9] vs -0.8 [1.2]; P = .29), vaginal maturation index (mean [SD] difference, 10.2 [17.4] vs 14.4 [17.1]; P = .15), vaginal epithelial thickness (mean [SD] difference, 0.021 [0.014] mm vs 0.013 [0.012] mm; P = .30), vaginal epithelial elasticity (mean [SD] difference, -1373 [3197] Pascals vs -2103 [3771] Pascals; P = .64). There were significant improvements in the overall analysis regardless of group in many outcomes. The 2 interventions were well tolerated, but tolerance was significantly lower in the CLT group than the SLT group (mean [SD] Likert scale score, 3.3 [1.3] vs 4.1 [1.0]; P = .007). No differences were observed in complications or serum estradiol levels. Conclusions and Relevance: In this randomized clinical trial, vaginal laser treatment was found to be safe after 6 months of follow-up, but no statistically significant differences in efficacy were observed between CLT and SLT. Trial Registration: ClinicalTrials.gov identifier: NCT04619485.

Development of a physiomimetic model of acute respiratory distress syndrome by using ECM hydrogels and organ-on-a-chip devices.

Acute Respiratory Distress Syndrome is one of the more common fatal complications in COVID-19, characterized by a highly aberrant inflammatory response. Pre-clinical models to study the effect of cell therapy and anti-inflammatory treatments have not comprehensively reproduced the disease due to its high complexity. This work presents a novel physiomimetic in vitro model for Acute Respiratory Distress Syndrome using lung extracellular matrix-derived hydrogels and organ-on-a-chip devices. Monolayres of primary alveolar epithelial cells were cultured on top of decellullarized lung hydrogels containing primary lung mesenchymal stromal cells. Then, cyclic stretch was applied to mimic breathing, and an inflammatory response was induced by using a bacteriotoxin hit. Having simulated the inflamed breathing lung environment, we assessed the effect of an anti-inflammatory drug (i.e., dexamethasone) by studying the secretion of the most relevant inflammatory cytokines. To better identify key players in our model, the impact of the individual factors (cyclic stretch, decellularized lung hydrogel scaffold, and the presence of mesenchymal stromal cells) was studied separately. Results showed that developed model presented a more reduced inflammatory response than traditional models, which is in line with what is expected from the response commonly observed in patients. Further, from the individual analysis of the different stimuli, it was observed that the use of extracellular matrix hydrogels obtained from decellularized lungs had the most significant impact on the change of the inflammatory response. The developed model then opens the door for further in vitro studies with a better-adjusted response to the inflammatory hit and more robust results in the test of different drugs or cell therapy.

Lung Extracellular Matrix Hydrogels Enhance Preservation of Type II Phenotype in Primary Alveolar Epithelial Cells.

One of the main limitations of in vitro studies on lung diseases is the difficulty of maintaining the type II phenotype of alveolar epithelial cells in culture. This fact has previously been related to the translocation of the mechanosensing Yes-associated protein (YAP) to the nuclei and Rho signaling pathway. In this work, we aimed to culture and subculture primary alveolar type II cells on extracellular matrix lung-derived hydrogels to assess their suitability for phenotype maintenance. Cells cultured on lung hydrogels formed monolayers and maintained type II phenotype for a longer time as compared with those conventionally cultured. Interestingly, cells successfully grew when they were subsequently cultured on a dish. Moreover, cells cultured on a plate showed the active form of the YAP protein and the formation of stress fibers and focal adhesions. The results of chemically inhibiting the Rho pathway strongly suggest that this is one of the mechanisms by which the hydrogel promotes type II phenotype maintenance. These results regarding protein expression strongly suggest that the chemical and biophysical properties of the hydrogel have a considerable impact on the transition from ATII to ATI phenotypes. In conclusion, culturing primary alveolar epithelial cells on lung ECM-derived hydrogels may facilitate the prolonged culturing of these cells, and thus help in the research on lung diseases.