Diterpenoid Vinigrol specifically activates ATF4/DDIT3-mediated PERK arm of unfolded protein response to drive non-apoptotic death of breast cancer cells.

Vinigrol is a natural diterpenoid with unprecedented chemical structure, driving great efforts into its total synthesis in the past decades. Despite anti-hypertension and anti-clot ever reported, comprehensive investigations on bioactions and molecular mechanisms of Vinigrol are entirely missing. Here we firstly carried out a complete functional prediction of Vinigrol using a transcriptome-based strategy coupled with multiple bioinformatic analyses and identified "anti-cancer" as the most prominent biofunction ahead of anti-hypertension and anti-depression/psychosis. Broad cytotoxicity was subsequently confirmed on multiple cancer types. Further mechanistic investigation on several breast cancer cells revealed that its anti-cancer effect was mainly through activating PERK/eIF2α arm of unfolded protein response (UPR) and subsequent non-apoptotic cell death independent of caspase activities. The other two branches of UPR, IRE1α and ATF6, were functionally irrelevant to Vinigrol-induced cell death. Using CRISPR/Cas9-based gene activation, repression, and knockout systems, we identified the essential contribution of ATF4 and DDIT3, not ATF6, to the death process. This study unraveled a broad anti-cancer function of Vinigrol and its underlying targets and regulatory mechanisms. It paved the way for further inspection on the structure-efficacy relationship of the whole compound family, making them a novel cluster of PERK-specific stress activators for experimental and clinical uses.

The Single-Cell Level Perspective of the Tumor Microenvironment and Its Remodeling by CAR-T Cells.

The tumor microenvironment (TME) is a complex milieu consisting of lymphoid cells, myeloid cells, fibroblasts, and multiple molecules, which play a key role in tumor progression and immunotherapy. TME is characterized by immune-suppressive features, which release anti-inflammatory cytokines such as IL-4 and TGFß to skew the T cells to a Th2 state as well to polarize tumor-associated macrophages (TAMs) to an anti-inflammatory phenotype to curb the immunotherapy. Considering the heterogeneity of the TME and its role in determining response to chimeric antigen receptor (CAR)-T cells, delineating TME at a single-cell level will provide useful information for cancer treatment. First, we discuss cellular and molecular features that curb the response to CAR-T cells, for example, high expression of immune checkpoint molecules (PD-1, LAG3) and anti-inflammatory cytokines (IL-4, TGFb) that block CAR-T cell function. Then, we summarize how newly invented single-cell technologies such as spatial multi-omics would benefit the understanding of cancer immunotherapy. Finally, we will further describe recent attempts of CAR-T to remodel TME by arming the CAR-T with anti-PD-1 single-chain variants or Th1 triggering cytokines (such as IL-7, IL-12) to remodel TME into a pro-inflammatory state. Herein, we review the single-cell-level signatures of TME and the strategies of CAR-T to remodel TME.

The Tumor Microenvironment Reprograms Immune Cells.

Tumor tissue comprises a highly complex network of diverse cell types. The tumor microenvironment (TME) can be mainly subdivided into cancer cells and stromal cell compartments, the latter include different types of immune cells, fibroblasts, endothelial cells, and pericytes. Tumor cells reprogram immune cells and other stromal cells in the TME to constrain their antitumor capacity by creating an immunosuppressive milieu and metabolism competition. Moreover, the reprogramming effect on immune cells is localized not only in the tumor but also at the systemic level. With wide application of single-cell sequencing technology, tumor-specific characteristics of immune cells and other stromal cells in the TME have been dissected. In this review, we mainly focus on how tumor cells reprogram immune cells both within the TME and peripheral blood. This information can further help us to improve the efficiency of current immunotherapy as well as bring up new ideas to combat cancer.

Novel Ferrocene Derivatives Induce Apoptosis through Mitochondria-Dependent and Cell Cycle Arrest via PI3K/Akt/mTOR Signaling Pathway in T Cell Acute Lymphoblastic Leukemia.

T cell acute lymphoblastic leukemia (T-ALL) is one of the most common causes of death in pediatric malignancies. However, the clinical chemotherapy for T-ALL has been limited by numerous side effects, emphasizing that novel anti-T-ALL drugs are urgently needed. Herein, a series of 2-acyl-1-dimethylaminomethyl-ferrocenes for cancer therapy have been evaluated. Among them, F1 and F3 exhibited potent cytotoxicity against T-ALL cell lines, especially Jurkat cells, with low cytotoxicity for normal cells. Further mechanistic studies revealed that F1 and F3 could induce apoptosis in Jurkat cells by destructing mitochondrial membrane, enhancing reactive oxygen species (ROS) generation, decreasing the Bcl-2/Bax ratio, releasing Cytochrome c, and increasing the expression of Cleaved Caspase-9/-3 and Cleaved PARP. Additionally, F1 and F3 could suppress cell proliferation and arrest the cell cycle at G0/G1 phase through the PI3K/Akt/mTOR signaling pathway by down-regulating the expression of CDK6, Cyclin D1, p-Akt, p-GSK-3ß, p-mTOR, p-p70 S6K, and up-regulating the expression of P21 and P27, which would also be a possible mechanism. Consequently, ferrocene derivatives F1 and F3 could induce apoptosis through a mitochondria-dependent pathway mediated by ROS, and cell cycle arrest at G0/G1 phase via the PI3K/Akt/mTOR signaling pathway in Jurkat cells. The present study provided fundamental insights into the clinical application of F1 and F3 for the treatment of T-ALL.