Single-cell RNA sequencing reveals cancer stem-like cells and dynamics in tumor microenvironment during cholangiocarcinoma progression

Cholangiocarcinoma is a malignancy of the bile ducts that is driven by activities of cancer stem-like cells and characterized by a heterogeneous tumor microenvironment. To better understand the transcriptional profiles of cancer stem-like cells and dynamics in the tumor microenvironment during the progression of cholangiocarcinoma, we performed single-cell RNA analysis on cells collected from three different timepoints of tumorigenesis in a YAP/AKT mouse model. Bulk RNA sequencing data from TCGA (The Cancer Genome Atlas program) and ICGC cohorts were used to verify and support the finding. In vitro and in vivo experiments were performed to assess the stemness of cancer stem-like cells. We identified Tm4sf1high malignant cells as cancer stem-like cells. Across timepoints of cholangiocarcinoma formation in YAP/AKT mice, we found dynamic change in cancer stem-like cell/stromal/immune cell composition. Nevertheless, the dynamic interaction among cancer stem-like cells, immune cells, and stromal cells at different timepoints was elaborated. Collectively, these data serve as a useful resource for better understanding cancer stem-like cell and malignant cell heterogeneity, stromal cell remodeling, and immune cell reprogramming. It also sheds new light on transcriptomic dynamics during cholangiocarcinoma progression at single-cell resolution

Towards the stable chelation of radium for biomedical applications with an 18-membered macrocyclic ligand.

Targeted alpha therapy is an emerging strategy for the treatment of disseminated cancer. [223Ra]RaCl2 is the only clinically approved alpha particle-emitting drug, and it is used to treat castrate-resistant prostate cancer bone metastases, to which [223Ra]Ra2+ localizes. To specifically direct [223Ra]Ra2+ to non-osseous disease sites, chelation and conjugation to a cancer-targeting moiety is necessary. Although previous efforts to stably chelate [223Ra]Ra2+ for this purpose have had limited success, here we report a biologically stable radiocomplex with the 18-membered macrocyclic chelator macropa. Quantitative labeling of macropa with [223Ra]Ra2+ was accomplished within 5 min at room temperature with a radiolabeling efficiency of >95%, representing a significant advancement over conventional chelators such as DOTA and EDTA, which were unable to completely complex [223Ra]Ra2+ under these conditions. [223Ra][Ra(macropa)] was highly stable in human serum and exhibited dramatically reduced bone and spleen uptake in mice in comparison to bone-targeted [223Ra]RaCl2, signifying that [223Ra][Ra(macropa)] remains intact in vivo. Upon conjugation of macropa to a single amino acid β-alanine as well as to the prostate-specific membrane antigen-targeting peptide DUPA, both constructs retained high affinity for 223Ra, complexing >95% of Ra2+ in solution. Furthermore, [223Ra][Ra(macropa-β-alanine)] was rapidly cleared from mice and showed low 223Ra bone absorption, indicating that this conjugate is stable under biological conditions. Unexpectedly, this stability was lost upon conjugation of macropa to DUPA, which suggests a role of targeting vectors in complex stability in vivo for this system. Nonetheless, our successful demonstration of efficient radiolabeling of the β-alanine conjugate with 223Ra and its subsequent stability in vivo establishes for the first time the possibility of delivering [223Ra]Ra2+ to metastases outside of the bone using functionalized chelators, marking a significant expansion of the therapeutic utility of this radiometal in the clinic

Nontranscriptional Role of Hif-1α in Activation of γ-Secretase and Notch Signaling in Breast Cancer

γ-Secretase is composed of four proteins that are obligatory for protease activity: presenilin, nicastrin, Aph1, and Pen-2. Despite the progress toward understanding the function of these individual subunits, there is no information available pertaining to the modulation of γ-secretase in response to environmental changes in cells. Here, we show that hypoxia upregulates γ-secretase activity through a direct interaction with Hif-1α, revealing an unconventional function for Hif-1α as an enzyme subunit, which is distinct from its canonical role as a transcription factor. Moreover, hypoxia-induced cell invasion and metastasis are alleviated by either γ-secretase inhibitors or a dominant-negative Notch coactivator, indicating that γ-secretase/Notch signaling plays an essential role in controlling these cellular processes. The present study reveals a mechanism in which γ-secretase can achieve temporal control through conditional interactions with regulatory proteins, such as Hif-1α, under select physiological and pathological conditions