Single-cell proteo-transcriptomic profiling reveals altered characteristics of stem and progenitor cells in patients receiving cytoreductive hydroxyurea in early-phase chronic myeloid leukemia.

Hydroxyurea (HU) is frequently used in the early phase of chronic myeloid leukemia (CML) to achieve cytoreduction prior to tyrosine kinase inhibitor (TKI) therapy. However, its impact on CML stem and progenitor cells (SPC) remains largely unknown. This study utilized targeted proteo-transcriptomic expression data on 596 genes and 51 surface proteins in 60,000 CD14-CD34+ cells from chronic phase CML patients to determine effects of shortterm HU treatment (4-19 days) on CML SPC. Peripheral blood and bone marrow samples were obtained from 17 CML patients eligible for short-term HU treatment (three patients before and after HU; seven patients before HU; and seven patients after HU) and subjected to single-cell CITE-seq and/or flow cytometry analysis. The analysis revealed enhanced frequencies of hemoglobin-expressing (HBA1, HBA2, HBB) erythroid progenitor cells in blood and bone marrow following HU treatment. In addition, there was an accumulation of cell subsets with S/G2/M phase-related gene and protein expression, likely representing cells arrested in, or progressing slowly through, the cell cycle. The increased frequency of cells in S/G2/M phase after HU was observed already among the most immature leukemic stem cells (LSC), and patients with a high fraction of LSC in the S/G2/M phase showed poor responsiveness to TKI treatment. We conclude that short-term HU treatment entails differentiation of erythroid progenitor cells and alters the characteristics of LSC in CML. The results imply that studies of LSC and progenitor populations in CML should take effects of initial HU therapy into account.

Histamine dihydrochloride and low-dose interleukin-2 has antileukemic efficacy in NPM1-mutated and myelomonocytic/monocytic acute myeloid leukemia.

Not available.

Impact of Surgery-Induced Myeloid-derived Suppressor Cells and the NOX2/ROS Axis on Postoperative Survival in Human Pancreatic Cancer.

Preclinical studies imply that surgery triggers inflammation that may entail tumor outgrowth and metastasis. The potential impact of surgery-induced inflammation in human pancreatic cancer is insufficiently explored. This study included 17 patients with periampullary cancer [pancreatic ductal adenocarcinoma (PDAC) n = 14, ampullary carcinoma n = 2, cholangiocarcinoma n = 1] undergoing major pancreatic cancer surgery with curative intent. We analyzed the potential impact of preoperative and postoperative immune phenotypes and function on postoperative survival with >30 months follow-up. The surgery entailed prompt expansion of monocytic myeloid-derived suppressor cells (M-MDSC) that generated NOX2-derived reactive oxygen species (ROS). Strong induction of immunosuppressive M-MDSC after surgery predicted poor postoperative survival and coincided with reduced functionality of circulating natural killer (NK) cells. The negative impact of surgery-induced M-MDSC on survival remained significant in separate analysis of patients with PDAC. M-MDSC-like cells isolated from patients after surgery significantly suppressed NK cell function ex vivo, which was reversed by inhibition of NOX2-derived ROS. High NOX2 subunit expression within resected tumors from patients with PDAC correlated with poor survival whereas high expression of markers of cytotoxic cells associated with longer survival. The surgery-induced myeloid inflammation was recapitulated in vivo in a murine model of NK cell-dependent metastasis. Surgical stress thus induced systemic accumulation of M-MDSC-like cells and promoted metastasis of NK cell-sensitive tumor cells. Genetic or pharmacologic suppression of NOX2 reduced surgery-induced inflammation and distant metastasis in this model. We propose that NOX2-derived ROS generated by surgery-induced M-MDSC may be targeted for improved outcome after pancreatic cancer surgery. SIGNIFICANCE: Pancreatic cancer surgery triggered pronounced accumulation of NOX2+ myeloid-derived suppressor cells that inhibited NK cell function and negatively prognosticated postoperative patient survival. We propose the targeting of M-MDSC as a conceivable strategy to reduce postoperative immunosuppression in pancreatic cancer.

The effect of a single dose of nivolumab prior to isolated limb perfusion for patients with in-transit melanoma metastases: An interim analysis of a phase Ib/II randomized double-blind placebo-controlled trial (NivoILP trial).

OBJECTIVE: ILP has shown to achieve high response rates in patients with melanoma ITM. Possibly there is a synergistic mechanism of action of ILP and anti-PD1. The aim of this trial was to investigate the safety and efficacy of adding a single dose of systemic anti-PD1 to isolated limb perfusion (ILP) for patients with melanoma in-transit metastases (ITM). METHODS: In this placebo controlled double-blind phase Ib/II trial, patients with melanoma ITM were randomized 1:1 to either a single systemic dose of nivolumab or placebo one day prior to ILP. The primary endpoint was complete response (CR) rate at three months, and safety in terms of incidence and severity of adverse events (AEs). RESULTS: A total of 20 patients were included. AEs of any grade occurred in 90% of patients in the nivolumab arm and in 80% in the placebo arm within three months after ILP. Grade 3 AEs were reported in 40% and 30% respectively, most commonly related to wound infection, wound dehiscence, or skin necrosis. There were no grade 4 or 5 AEs reported. The CR rate was 75% in the nivolumab arm and 60% in the placebo arm. The 1-year local progression-free rate was 86% in the nivolumab arm and 67% in the placebo arm. The 1-year OS was 100% in both arms. CONCLUSION: For patients with melanoma ITM, the addition of a single systemic dose of nivolumab the day before ILP is considered safe and feasible with promising efficacy. Accrual will continue in a phase 2 trial.