A TCF4-dependent gene regulatory network confers resistance to immunotherapy in melanoma.

To better understand intrinsic resistance to immune checkpoint blockade (ICB), we established a comprehensive view of the cellular architecture of the treatment-naive melanoma ecosystem and studied its evolution under ICB. Using single-cell, spatial multi-omics, we showed that the tumor microenvironment promotes the emergence of a complex melanoma transcriptomic landscape. Melanoma cells harboring a mesenchymal-like (MES) state, a population known to confer resistance to targeted therapy, were significantly enriched in early on-treatment biopsies from non-responders to ICB. TCF4 serves as the hub of this landscape by being a master regulator of the MES signature and a suppressor of the melanocytic and antigen presentation transcriptional programs. Targeting TCF4 genetically or pharmacologically, using a bromodomain inhibitor, increased immunogenicity and sensitivity of MES cells to ICB and targeted therapy. We thereby uncovered a TCF4-dependent regulatory network that orchestrates multiple transcriptional programs and contributes to resistance to both targeted therapy and ICB in melanoma.

Urokinase-type plasminogen activator (uPA) regulates invasion and matrix remodelling in colorectal cancer.

Background: Cancer cells remodel their local physical environment through processes of matrix reorganisation, deposition, stiffening and degradation. Urokinase-type plasminogen activator (uPA), which is encoded by the PLAU gene, is an extracellular proteolytic enzyme known to be involved in cancer progression and tumour microenvironment (TME) remodelling. Perturbing uPA therefore has a strong potential as a mechano-based cancer therapy. This work is a bioengineering investigation to validate whether 1) uPA is involved in matrix degradation and 2) preventing matrix degradation by targeting uPA can reduce cancer cell invasion and metastasis. Methods: To this aim, we used an engineered 3D in vitro model, termed the tumouroid, that appropriately mimics the tumour's native biophysical environment (3 kPa). A CRISPR-Cas9 mediated uPA knockout was performed to introduce a loss of function mutation in the gene coding sequence. Subsequently, to validate the translational potential of blocking uPA action, we tested a pharmacological inhibitor, UK-371,801. The changes in matrix stiffness were measured by atomic force microscopy (AFM). Invasion was quantified using images of the tumouroid, obtained after 21 days of culture. Results: We showed that uPA is highly expressed in invasive breast and colorectal cancers, and these invasive cancer cells locally degrade their TME. PLAU (uPA) gene knock-out (KO) completely stopped matrix remodelling and significantly reduced cancer invasion. Many invasive cancer gene markers were also downregulated in the PLAU KO tumouroids. Pharmacological inhibition of uPA showed similarly promising results, where matrix degradation was reduced and so was the cancer invasion. Conclusion: This work supports the role of uPA in matrix degradation. It demonstrates that the invasion of cancer cells was significantly reduced when enzymatic breakdown of the TME matrix was prevented. Collectively, this provides strong evidence of the effectiveness of targeting uPA as a mechano-based cancer therapy.

Women's Mental Health as a Factor Associated with Exclusive Breastfeeding and Breastfeeding Duration: Data from a Longitudinal Study in Greece.

BACKGROUND: This study investigated the relationship between exclusive breastfeeding and breastfeeding duration, and maternal psychological well-being in the perinatal period. METHODS: A longitudinal study involving a retrospective follow-up of a group of 1080 women from pregnancy to the 1st year postpartum, who gave birth during the 5-year period between January 2014 and January 2019 in Athens, Greece, was designed. Women's history and two psychometric tools-the Edinburg Postpartum Depression Scale (EPDS) and the Patient Health Questionnaire-9 (PHQ-9) administered at 5-time points-were used for data collection. Logistic regression analysis and a series of multiple analysis of variance (MANOVA) tests were performed. RESULTS: The chance for exclusive breastfeeding (giving only breast milk) appeared to decrease (a) with an increase of the scores for psychometric tools antenatally (PHQ-9, p = 0.030) or at the 6th week postpartum (EPDS, p < 0.001 and PHQ-9, p < 0.001), (b) with an increase in the number of psychotherapeutic sessions needed antenatally (p = 0.030), and (c) when the initiation of psychotherapy was necessary postpartum (p = 0.002). Additionally, a shorter duration of any breastfeeding (with or without formula or other types of food/drink) seems to be associated with (a) the occurrence of pathological mental health symptoms (p = 0.029), (b) increased PHQ-9 scores antenatally (p = 0.018), (c) increased EPDS scores at the 6th week (p = 0.004) and the 12th month postpartum (p = 0.031), (d) the initiation of psychotherapy postpartum (p = 0.040), and e) the need for more than 13 psychotherapeutic sessions (p = 0.020). CONCLUSIONS: This study demonstrates a negative relationship between exclusive breastfeeding and breastfeeding duration, and poor maternal mental health in the perinatal period.