It's about TIME - Gal-9 as a potential immunotherapeutic target in pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) remains one of the most lethal malignancies, characterized by an extremely poor prognosis and limited therapeutic options. Central to the progression and immune evasion of PDAC is the tumor (immune) microenvironment (TIME), where immune checkpoint proteins such as galectin-9 (Gal-9) play pivotal roles. Gal-9 significantly contributes to the immunosuppressive milieu of PDAC by interacting with various immune cells, such as T cells, macrophages, and myeloid-derived suppressor cells (MDSCs). These interactions suppress anti-tumor immunity, thus facilitating tumor growth and metastasis. This review comprehensively examines the multifaceted role of Gal-9 in the TIME of PDAC, detailing its mechanisms of action, including the induction of regulatory T cells, polarization of tumor-associated macrophages, and modulation of apoptotic pathways via Tim-3 and caspase activation. The therapeutic potential of targeting Gal-9, either alone or in combination with other immune checkpoint inhibitors such as anti-PD-L1, is also discussed, highlighting preclinical findings that suggest promising avenues for enhancing anti-tumor immune responses. By elucidating the complex biological activities of Gal-9 and its interactions within the TIME, this review underscores the importance of innovative therapeutic strategies aimed at mitigating the immunosuppressive effects of Gal-9 in PDAC.

Insights into the Identification of iPSC- and Monocyte-Derived Macrophage-Polarizing Compounds by AI-Fueled Cell Painting Analysis Tools

Macrophage polarization critically contributes to a multitude of human pathologies. Hence, modulating macrophage polarization is a promising approach with enormous therapeutic potential. Macrophages are characterized by a remarkable functional and phenotypic plasticity, with pro-inflammatory (M1) and anti-inflammatory (M2) states at the extremes of a multidimensional polarization spectrum. Cell morphology is a major indicator for macrophage activation, describing M1(-like) (rounded) and M2(-like) (elongated) states by different cell shapes. Here, we introduced cell painting of macrophages to better reflect their multifaceted plasticity and associated phenotypes beyond the rigid dichotomous M1/M2 classification. Using high-content imaging, we established deep learning- and feature-based cell painting image analysis tools to elucidate cellular fingerprints that inform about subtle phenotypes of human blood monocyte-derived and iPSC-derived macrophages that are characterized as screening surrogate. Moreover, we show that cell painting feature profiling is suitable for identifying inter-donor variance to describe the relevance of the morphology feature 'cell roundness' and dissect distinct macrophage polarization signatures after stimulation with known biological or small-molecule modulators of macrophage (re-)polarization. Our novel established AI-fueled cell painting analysis tools provide a resource for high-content-based drug screening and candidate profiling, which set the stage for identifying novel modulators for macrophage (re-)polarization in health and disease.