The two T cell inhibitory receptors PD-1 and TIM-3 are co-expressed during exhausted T cell differentiation, and recent evidence suggests that their crosstalk regulates T cell exhaustion and immunotherapy efficacy; however, the molecular mechanism is unclear. Here we show that PD-1 contributes to the persistence of PD-1+TIM-3+ T cells by binding to the TIM-3 ligand galectin-9 (Gal-9) and attenuates Gal-9/TIM-3-induced cell death. Anti-Gal-9 therapy selectively expands intratumoral TIM-3+ cytotoxic CD8 T cells and immunosuppressive regulatory T cells (Treg cells). The combination of anti-Gal-9 and an agonistic antibody to the co-stimulatory receptor GITR (glucocorticoid-induced tumor necrosis factor receptor-related protein) that depletes Treg cells induces synergistic antitumor activity. Gal-9 expression and secretion are promoted by interferon β and γ, and high Gal-9 expression correlates with poor prognosis in multiple human cancers. Our work uncovers a function for PD-1 in exhausted T cell survival and suggests Gal-9 as a promising target for immunotherapy.

Iron is an essential metal ion in the human body and usually dysregulated in cancers.However, a comprehensive overview of the iron-related genes and their clinical relevance in cancer is lacking. In this study, we utilized the expression profiling, proteomics, and epigenetics from the Cancer Genome Atlas database to systematically characterized the alterations of iron-related genes. There were multiple ironrelated genes with dysregulation across 14 cancers and some of these ectopic changes may be associated with aberrant DNA methylation. Meanwhile, a variety of genes were significantly associated with patient survival, especially in kidney renal clear cell carcinoma. Then differentially expressed genes were validated in clinical samples. Finally, we found deferoxamine and erastin could inhibit proliferation in various tumor cells and influence the expression of several iron-related genes.Overall, our study provides a comprehensive analysis of iron metabolism across cancers and highlights the potential treatment of iron targeted therapies for cancers. K E Y W O R D SDNA methylation, ferroptosis, iron metabolism, pan-cancer analysis, survival

In an ongoing investigation of 20-sulfonylamidine derivatives (9, YQL-9a) of camptothecin (1) as potential anticancer agents directly and selectively inhibiting topoisomerase (Topo) I, the sulfonylamidine pharmacophore was held constant, and a camptothecin derivatives with various substitution patterns were synthesized. The new compounds were evaluated for antiproliferative activity against three human tumor cell lines, A-549, KB, and multidrug resistant (MDR) KB subline (KBvin). Several analogues showed comparable or superior antiproliferative activity compared to the clinically prescribed 1 and irinotecan (3). Significantly, the 20-sulfonylamidine derivatives exhibited comparable cytotoxicity against KBvin, while 1 and 3 were less active against this cell line. Among them, compound 15c displayed much better cytotoxic activity than the controls 1, 3, and 9. Novel key structural features related to the antiproliferative activities were identified by structure-activity relationship (SAR) analysis. In a molecular docking model, compounds 9 and 15c interacted with Topo I-DNA through a different binding mode from 1 and 3. The sulfonylamidine side chains of 9 and 15c could likely form direct hydrogen bonds with Topo I, while hydrophobic interaction with Topo I and π-π stacking with double strand DNA were also confirmed as binding driving forces. The results from docking models were consistent with the SAR conclusions. The introduction of bulky substituents at the 20-position contributed to the altered binding mode of the compound by allowing them to form new interactions with Topo I residues. The information obtained in this study will be helpful for the design of new derivatives of 1 with most promising anticancer activity.

Edited by Xiao-Fan WangReactive oxygen species (ROS) are cellular by-products produced from metabolism and also anticancer agents, such as ionizing irradiation and chemotherapy drugs. The ROS H 2 O 2 has high rates of production in cancer cells because of their rapid proliferation. ROS oxidize DNA, protein, and lipids, causing oxidative stress in cancer cells and making them vulnerable to other stresses. Therefore, cancer cell survival relies on maintaining ROS-induced stress at tolerable levels. Hepatocyte growth factor receptor (c-MET) is a receptor tyrosine kinase overexpressed in malignant cancer types, including breast cancer. Full-length c-MET triggers a signal transduction cascade from the plasma membrane that, through downstream signaling proteins, up-regulates cell proliferation and migration. Recently, c-MET was shown to interact and phosphorylate poly(ADP-ribose) polymerase 1 in the nucleus and to induce poly(ADP-ribose) polymerase inhibitor resistance. However, it remains unclear how c-MET moves from the cell membrane to the nucleus. Here, we demonstrate that H 2 O 2 induces retrograde transport of membrane-associated full-length c-MET into the nucleus of human MCF10A and MCF12A or primary breast cancer cells. We further show that knocking down either coatomer protein complex subunit ␥1 (COPG1) or Sec61 translocon ␤ subunit (SEC61␤) attenuates the accumulation of full-length nuclear c-MET. However, a c-MET kinase inhibitor did not block nuclear c-MET transport. Moreover, nuclear c-MET interacted with KU proteins in breast cancer cells, suggesting a role of full-length nuclear c-MET in ROS-induced DNA damage repair. We conclude that a membrane-bound retrograde vesicle transport mechanism facilitates membrane-to-nucleus transport of c-MET in breast cancer cells.Reactive oxygen species (ROS) 2 are highly reactive molecules derived from oxygen metabolism mainly produced during metabolic processes, as well as from ionizing radiation (IR) and chemotherapy drugs (1). ROS can be grouped into either radical molecules, such as hydroxyl radical and superoxide anion, or nonradical compounds, such as H 2 O 2 , which plays a key role in physiological oxidative stress (2). Because ROS can lead to oxidation of macromolecules, including DNA, protein, and lipids, precise homeostasis control of ROS is crucial to both normal and cancer cells. A moderate level of ROS is important for physiological regulations but can also activate oncogenic signaling molecules, leading to human cancer initiation and progression (1,3,4). However, excessive ROS can also induce DNA damage and apoptosis in cancer cells (3). Therefore, enhancing ROS level is a strategy widely applied in cancer treatment (1,3,5). In cancer cells, the ROS H 2 O 2 can be generated during ligand-induced receptor tyrosine kinase (RTK) activation and can further enhance RTK autophosphorylation by inhibiting protein-tyrosine phosphatase activity (6). In addition to the alteration of RTK signaling, ROS also enhances the accumulation of nuclear RTKs such as c-MET and e...