Lifeng Ma

B lymphocytes are essential mediators of humoral immunity and play multiple roles in human cancer. To decode the functions of tumor-infiltrating B cells, we generated a B cell blueprint encompassing single-cell transcriptome, B cell-receptor repertoire, and chromatin accessibility data across 20 different cancer types (477 samples, 269 patients). B cells harbored extraordinary heterogeneity and comprised 15 subsets, which could be grouped into two independent developmental paths (extrafollicular versus germinal center). Tumor types grouped into the extrafollicular pathway were linked with worse clinical outcomes and resistance to immunotherapy. The dysfunctional extrafollicular program was associated with glutamine-derived metabolites through epigenetic-metabolic cross-talk, which promoted a T cell-driven immunosuppressive program. These data suggest an intratumor B cell balance between extrafollicular and germinal-center responses and suggest that humoral immunity could possibly be harnessed for B cell-targeting immunotherapy.

Hepatocellular carcinoma (HCC) is an angiogenesis-dependent tumor, and angiogenesis plays pivotal roles in progression and hematogenous metastasis. Upregulating NDRG2 expression could inhibit endothelial cell proliferation and tumor angiogenesis. However, the development of angiogenesis is a complicated and dynamic process, and the specific mechanisms that NDRG2 influences its progression are largely unknown. Conditioned media (CM) was collected from HCC cells. Cell viability, migration assay, tube formation, and western blot were used to evaluate the effect of NDRG2 on angiogenesis in HCC cells. ELISA assay was used to measure the level of VEGFA in CM. CM from NDRG2 knockdown cells significantly promoted HUVECs proliferation, migration, and tube formation compared with control cells. The level of VEGFA in CM was increased by NDRG2 knockdown relative to the control group. The expression of VEGFA, HIF-1α, and p-Akt was significantly increased in NDRG2 knockdown cells. CM from NDRG2 knockdown cells with VEGFA antibody failed to induce HUVEC proliferation, migration, and tube formation. YC-1 significantly inhibited the level of VEGFA in CM from NDRG2 knockdown cells. YC-1 also inhibited the expression of VEGFA and HIF-1α. Therefore, NDRG2 inhibition promoted the angiogenesis of HCC via VEGFA and may be used to be an anti-angiogenesis target.

LncRNAs have been reported to be involved in the initiation and progression of cholangiocarcinoma (CCA), although the mechanisms by which this occurs remains unknown. The current study aimed to reveal the clinico-pathological relationship of RHPN1-AS1 expressed with CCA, and also investigate the functions of RHPN1-AS1 both in vivo and in vitro. RHPN1-AS1 was overexpressed in CCA cell proliferation as well as promoted xenograft growth in vivo. Mechanistically, DANCR upregulated the expression of YAP1 by competitively binding to miR-345-5p. Importantly, RHPN1-AS1 level was positively correlated with YAP1 expression level in CCA tissues (P<0.05). Moreover, Kaplan-Meier curves showed that YAP1 overexpression predicted a poor outcome of CCA patients (P=0.004). Taken together, our results suggested that RHPN1-AS1 might be a remarkable biomarker to evaluate prognosis in CCA. The RHPN1-AS1/YAP1 axis may provide new strategies for CCA clinical practice.

BACKGROUND: Tumour suppressor genes, exemplified by TP53 (encoding the human p53), function as critical guardians against tumourigenesis. Germline TP53-inactivating mutations underlie Li-Fraumeni syndrome, a hereditary cancer predisposition disorder characterised by early-onset pan-tissue malignancies. However, the context-dependent tumour-suppressive mechanisms of p53 remain incompletely elucidated. This study aims to investigate the disruption of cellular homeostasis and tumourigenic mechanisms following p53 inactivation across distinct cell lineages. METHODS: Trp53 (encoding mouse p53) knockout mouse model was employed to study molecular alterations under p53-deficient conditions. Multi-omics analyses - including single-cell transcriptomics, single-cell ATAC-seq, spatial transcriptomics, whole genome sequencing, and CUT&Tag - were integrated to construct a Trp53 functional cell landscape. Deep learning-based gene network models were employed to reconstruct p53 regulatory networks and simulate in silico perturbations caused by p53 loss. RESULTS: Our analyses revealed transitional dynamics in immune, stromal, and epithelial cells from normal physiology to p53-deficient states and subsequent tumourigenesis. These transitions implicated critical pathways such as cell cycle regulation, stress response, metabolic reprogramming, and immune modulation, displaying both lineage-conserved and lineage-specific features. Tumour-prone cell populations exhibiting elevated differentiation plasticity were identified across lineages within tumourigenic trajectories. Spatial transcriptomic profiling confirmed the emergence of thymic tumour-initiating T-cell clusters characterised by deterministic chromatin architectural disruptions under p53-loss pressure. Notably, we uncovered a recurrent upregulation signature of ribosomal protein genes as an early pivotal molecular event preceding malignant transformation in p53-deficient oncogenesis. Finally, we decoded the p53 downstream regulatory network and computationally evaluated the perturbation effects of genetic inactivation at single-cell resolution. CONCLUSIONS: Our results elucidate the multiscale consequences of p53 inactivation while providing valuable resources for understanding tumour predisposition associated with p53-inactivating mutations and developing clinical interception strategies. KEY POINTS: Construction of a Trp53 functional cell landscape utilising single-cell multi-omics and spatial omics technologies. Reconstruction of p53 downstream regulatory relationships with lineage heterogeneity via machine learning-based gene network modelling. Dissection of shared and lineage-specific features during cross-lineage tumourigenesis under p53 deficiency.