Targeting C-type lectin-like molecule-1 for antibody-mediated immunotherapy in acute myeloid leukemia

Background

C-type lectin-like molecule-1 is a transmembrane receptor expressed on myeloid cells, acute myeloid leukemia blasts and leukemic stem cells. To validate the potential of this receptor as a therapeutic target in acute myeloid leukemia, we generated a series of monoclonal antibodies against the extracellular domain of C-type lectin-like molecule-1 and used them to extend the expression profile analysis of acute myeloid leukemia cells and to select cytotoxic monoclonal antibodies against acute myeloid leukemia cells in preclinical models.

Design and Methods

C-type lectin-like molecule-1 expression was analyzed in acute myeloid leukemia cell lines, and in myeloid derived cells from patients with acute myeloid leukemia and healthy donors. Anti-C-type lectin-like molecule-1 antibody-mediated in vitro cytotoxic activity against acute myeloid leukemia blasts/cell lines and in vivo anti-cancer activity in a mouse xenograft model were assessed. Internalization of C-type lectin-like molecule-1 monoclonal antibodies upon receptor ligation was also investigated.

Results

C-type lectin-like molecule-1 was expressed in 86.5% (45/52) of cases of acute myeloid leukemia, in 54.5% (12/22) of acute myeloid leukemia CD34⁺/CD38⁻ stem cells, but not in acute lymphoblastic leukemia blasts (n=5). Selected anti-C-type lectin-like molecule-1 monoclonal antibodies mediated dose-dependent complement-dependent cytotoxicity and antibody-dependent cellular cytotoxicity specifically against acute myeloid leukemia-derived cell lines. Exogenous expression of the transmembrane receptor in HEK293 cells rendered the cells susceptible to antibody-mediated killing by monoclonal antibodies to the receptor. Furthermore, these monoclonal antibodies demonstrated strong complement-dependent cytotoxicity against freshly isolated acute myeloid leukemia blasts (15/16 cases; 94%). The monoclonal antibodies were efficiently internalized upon binding to C-type lectin-like molecule-1 in HL-60 cells. Moreover, a lead chimeric C-type lectin-like molecule-1 monoclonal antibody reduced the tumor size in xenograft mice implanted with HL-60 cells.

Conclusions

Our results demonstrate that targeting C-type lectin-like molecule-1 with specific cytotoxic monoclonal antibodies is an attractive approach which could lead to novel therapies for acute myeloid leukemia.     

Short-Term PCB (Aroclor 1254) Toxicity on Few Phosphatases in Mice Brain

The present communication reports the dose and duration dependent toxicity of a PCB, Aroclor 1254, to a few ion dependent ATPases, Acid phosphatase, Alkaline phosphatase and Glucose-6-phosphatase in the whole brain tissue of mice. Two groups of mice were subjected to two sublethal doses (0.1 and 1 mg kgbw⁻¹ day⁻¹) of PCB orally and exposed for 4, 8 or12 days. A separate control group received the corn oil vehicle for the same exposure times. The observed results indicated exposure duration dependent changes in the enzymatic levels in the brain. The results suggest that the alteration in the enzymatic activity was possibly due to imposed oxidative stress generated by Aroclor 1254 on membrane-bound ion-dependent ATPases and other phosphatases in the brain tissue.     

Indirect treatment comparison of two non-invasive patient-controlled analgesia treatments for acute post-operative pain management

Objectives: To evaluate the relative clinical efficacy, safety, and tolerability associated with two non-invasive patient-controlled analgesia (PCA) treatments, sufentanil sublingual tablet system (SSTS) and fentanyl iontophoretic patient-controlled transdermal system (PCTS). These two treatments have recently been approved in the EU for the management of acute moderate-to-severe post-operative pain in adult patients.

Methods: As no head-to-head trials comparing SSTS and PCTS currently exist, indirect treatment comparison (ITC) analyses were conducted to evaluate SSTS or PCTS versus intravenous (IV) morphine PCA.

Results: Five studies, four assessing PCTS and one assessing SSTS, were included in this analysis. SSTS had statistical or numerical advantages over PCTS for both patient global assessment (PGA) and healthcare professional global assessment (HPGA) outcomes at all time points investigated. SSTS was also associated with greater patient ease of use (weighted mean difference [WMD]: 0.13; 95% confidence interval [CI]: ?0.02–0.28) and a higher patient satisfaction score (WMD: 0.31; 95% CI: 0.05–0.57; p?=?.019) compared with PCTS. In terms of tolerability, all-cause withdrawals from treatment were reported to be less likely with SSTS (risk ratio: 0.65; 95% CI: 0.42–1.02). No significant differences were observed between SSTS and PCTS in terms of safety and adverse events.

Conclusions: In the absence of direct head-to-head data, the combination of promising phase III trial results compared to IV morphine PCA, a SLR comparison against other opioid treatments, and the results of this exploratory analysis present a strong rationale in support of SSTS as a key option for management of post-operative pain.     

Discovery of Imidazopyridines as Potent Inhibitors of Indoleamine 2,3-Dioxygenase 1 for Cancer Immunotherapy

Indoleamine 2,3-dioxygenase 1 (IDO1) has been identified as a target for small-molecule immunotherapy for the treatment of a variety of cancers including renal cell carcinoma and metastatic melanoma. This work focuses on the identification of IDO1 inhibitors containing replacements or isosteres for the amide found in BMS-986205, an amide-containing, IDO1-selective inhibitor currently in phase III clinical trials. Detailed subsequently are efforts to identify a structurally differentiated IDO1 inhibitor via the pursuit of a variety of heterocyclic isosteres, leading to the discovery of highly potent, imidazopyridine-containing IDO1 inhibitors.     

Incidence and Risk of Intestinal and Extra-intestinal Complications in Medicaid Patients with Inflammatory Bowel Disease: A 5-Year Population-Based Study

Background and Aim  

Intestinal and extra-intestinal complications are associated with inflammatory bowel disease (IBD) but their exact incidence is not well known. In order to improve our understanding of their incidence and impact, we assessed the complications associated with ulcerative colitis (UC) and Crohn’s disease (CD) in a population-based study in Medicaid patients.     

Sorting in early endosomes reveals connections to docking- and fusion-associated factors

The early endosomes constitute a major sorting platform in eukaryotic cells. They receive material through fusion with endocytotic vesicles or with trafficking vesicles from the Golgi complex and later sort it into budding vesicles. While endosomal fusion is well understood, sorting is less characterized; the 2 processes are generally thought to be effected by different, unrelated machineries. We developed here a cell-free assay for sorting/budding from early endosomes, by taking advantage of their ability to segregate different cargoes (such as transferrin, cholera toxin subunit B, and low-density lipoprotein, LDL) into different carrier vesicles. Cargo separation required both carrier vesicle formation and active maturation of the endosomes. Sorting and budding were insensitive to reagents perturbing clathrin coats, coatomer protein complex-I (COPI) coats, dynamin, and actin, but were inhibited by anti-retromer subunit antibodies. In addition, the process required Rab-GTPases, phosphatidylinositol-3-phosphate, and, surprisingly, the docking factor early endosomal autoantigen 1 (EEA1). Sorting also required the function of the N-ethylmaleimide-sensitive factor (NSF), a well-known fusion cofactor, while it did not depend on preceding fusion of endosomes. We conclude that fusion, docking, and sorting/budding are interconnected at the molecular level.