Background and Aims Recent development of multiple treatments for human hepatocellular carcinoma (HCC) has allowed for the selection of combination therapy to enhance the effectiveness of monotherapy. Optimal selection of therapies is based on both HCC and its microenvironment. Therefore, it is critical to develop and validate preclinical animal models for testing clinical therapeutic solutions. Approach and Results We established cell line–based or patient‐derived xenograft–based humanized‐immune‐system mouse models with subcutaneous and orthotopic HCC. Mice were injected with human‐specific antibodies (Abs) to deplete human immune cells. We analyzed the transcription profiles of HCC cells and human immune cells by using real‐time PCR and RNA sequencing. The protein level of HCC tumor cells/tissues or human immune cells was determined by using flow cytometry, western blotting, and immunohistochemistry. The HCC tumor size was measured after single, dual‐combination, and triple‐combination treatment using N‐(1ʹ,2‐Dihydroxy‐1,2ʹ‐binaphthalen‐4ʹ‐yl)‐4‐methoxybenzenesulfonamide (C188‐9), bevacizumab, and pembrolizumab. In this study, human immune cells in the tumor microenvironment were strongly selected and modulated by HCC, which promoted the activation of the IL‐6/Janus kinase 2 (JAK2)/signal transducer and activator of transcription 3 (STAT3) signaling pathway in tumor cells and led to augmented HCC proliferation and angiogenesis by releasing angiogenic cytokines in humanized‐immune‐system mice with HCC. In particular, intratumor human cluster of differentiation–positive (hCD14+) cells could produce IL‐33 through damage‐associated molecular pattern/Toll‐like receptor 4/activator protein 1, which up‐regulated IL‐6 in other intratumor immune cells and activated the JAK2/STAT3 pathway in HCC. Specific knockdown of the CD14 gene in human monocytes could impair IL‐33 production induced by cell lysates. Subsequently, we evaluated the in vivo anti‐HCC effect of C188‐9, bevacizumab, and pembrolizumab. The results showed that the anti‐HCC effect of triple‐combination therapy was superior to that of single or dual treatments. Conclusions Humanized‐immune‐system HCC mouse models are suitable for identifying targets from cancer and immune components and for testing combinational therapies.

Differentiation of endometrial fibroblasts into specialized decidual cells controls embryo implantation and transforms the cycling endometrium into a semi-permanent, immune-protective matrix that accommodates the placenta throughout pregnancy. This process starts during the midluteal phase of the menstrual cycle with decidual transformation of perivascular cells (PVC) surrounding the terminal spiral arterioles and endometrial stromal cells (EnSC) underlying the luminal epithelium. Decidualization involves extensive cellular reprogramming and acquisition of a secretory phenotype, essential for coordinated placental trophoblast invasion. Secreted metabolites are an emerging class of signaling molecules, collectively known as the exometabolome. Here, we used liquid chromatography-mass spectrometry to characterize and analyze time-resolved changes in metabolite secretion (exometabolome) of primary PVC and EnSC decidualized over 8 days. PVC were isolated using positive selection of the cell surface marker SUSD2. We identified 79 annotated metabolites differentially secreted upon decidualization, including prostaglandin, sphingolipid, and hyaluronic acid metabolites. Secreted metabolites encompassed 21 metabolic pathways, most prominently glycerolipid and pyrimidine metabolism. Although temporal exometabolome changes were comparable between decidualizing PVC and EnSC, 32 metabolites were differentially secreted across the decidualization time-course. Further, targeted metabolomics demonstrated significant differences in secretion of purine pathway metabolites between decidualized PVC and EnSC. Taken together, our findings indicate that the metabolic footprints generated by different decidual subpopulations encode spatiotemporal information that may be important for optimal embryo implantation.

In recent decades, chimeric antigen receptor (CAR)–engineered immune effector cells have demonstrated promising antileukemic activity. Nevertheless, their efficacy remains unsatisfactory on solid cancers, plausibly due to the influence of tumor microenvironments (TME). In a novel mouse cancer model with a humanized immune system, tumor-infiltrating immunosuppressive leukocytes and exhausted programmed death protein-1 (PD-1) high T cells were found, which better mimic patient TME, allowing the screening and assessment of immune therapeutics. Particularly, membrane-bound programmed death ligand 1 (PD-L1) level was elevated on a tumor cell surface, which serves as an attractive target for natural killer (NK) cell–mediated therapy. Hematopoietic stem cell–derived CAR-NK (CAR pNK) cells targeting the PD-L1 showed enhanced in vitro and in vivo anti-solid tumor function. The CAR pNK cells and nivolumab resulted in a synergistic anti-solid tumor response. Together, our study highlights a robust platform to develop and evaluate the antitumor efficacy and safety of previously unexplored therapeutic regimens.