A80-2-07 Spatial Transcriptomic Analysis Reveals Om-85’s Therapeutic Mechanisms in Malignant Pulmonary Nodules

Background Spatial transcriptomics technology (Xenium), featuring core advantages of high spatial resolution, in situ resolution of cellular heterogeneity, and molecular interactions, has been widely applied for dissecting tumor heterogeneity and exploring drug mechanisms. Previous clinical cohort studies have confirmed the therapeutic potential of the bacterial lysate OM-85 (Bacterial Lysates, OM Pharma) in patients with malignant pulmonary nodules, and this study aimed to elucidate its underlying therapeutic mechanisms using Xenium technology. Methods KrasG12DTgfbr2-/-mutant mice (validated as a suitable model for malignant pulmonary nodules) were used in the experiment, with two time points: 5 weeks old and 15 weeks old. Each time point included a control group and an experimental group. The experimental group received OM-85 intervention, while the control group was treated with an equal volume of normal saline as control. Three core research questions were focused on:spatial expression differences of key molecule(proliferation,inflammation, and immunity-related)between tumor regions and normal tissue regions; the regulatory effect of OM-85 on the cellular interaction network in tumor regions; and age-related characteristics of tumor progression and drug response in mice of different ages (5 weeks old vs. 15 weeks old). Results OM-85 intervention significantly increased the abundance of innate immune cells (e.g., natural killer cells) within and adjacent to tumor areas, accompanied by distinct changes in adaptive immune cell populations. Conclusions This study provides spatial molecular level experimental evidence for the immunomodulatory mechanism of OM-85 in the treatment of malignant pulmonary nodules, and offers scientific references for its clinical translation and the formulation of individualized treatment strategies.