Autologous NK cells as consolidation therapy following stem cell transplantation in multiple myeloma.

Few approaches have been made toward exploring autologous NK cells in settings of cancer immunotherapy. Here, we demonstrate the feasibility of infusing multiple doses of ex vivo activated and expanded autologous NK cells in patients with multiple myeloma (MM) post-autologous stem cell transplantation. Infused NK cells were detected in circulation up to 4 weeks after the last infusion. Elevations in plasma granzyme B levels were observed following each consecutive NK cell infusion. Moreover, increased granzyme B levels were detected in bone marrow 4 weeks after the last infusion. All measurable patients had objective, detectable responses after NK cell infusions in terms of reduction in M-component and/or minimal residual disease. The present study demonstrates that autologous NK cell-based immunotherapy is feasible in a setting of MM consolidation therapy. It opens up the possibility for usage of autologous NK cells in clinical settings where patients are not readily eligible for allogeneic NK cell-based immunotherapies.

Thyroid receptor ligands. Part 4: 4'-amido bioisosteric ligands selective for the thyroid hormone receptor beta.

Based on the examination of the X-ray crystallographic structures of the LBD of TRalpha and TRbeta in complex with KB-141 (2), a number of novel 4'-hydroxy bioisosteric thyromimetics were prepared. Optimal affinity and beta-selectivity (33 times), was found with a medium-sized alkyl-substituted amido group; iso-butyl (12c). It can be concluded that bioisosteric replacements of the 4'-hydroxy position represent a new promising class of TRbeta-selective synthetic thyromimetics.

Selective thyroid hormone receptor-beta activation: a strategy for reduction of weight, cholesterol, and lipoprotein (a) with reduced cardiovascular liability.

Few treatments for obesity exist and, whereas efficacious therapeutics for hyperlipidemia are available, further improvements are desirable. Thyroid hormone receptors (TRs) regulate both body weight and cholesterol levels. However, thyroid hormones also have deleterious effects, particularly on the heart. The TR beta subtype is involved in cholesterol lowering and possibly elevating metabolic rate, whereas TR alpha appears to be more important for control of heart rate (HR). In the current studies, we examined the effect of TR beta activation on metabolic rate and HR with either TR alpha 1-/- mice or the selective TR beta agonist KB-141 in mice, rats, and monkeys. 3,5,3'-triiodi-l-thyronine (T3) had a greater effect on increasing HR in WT than in TR alpha-/- mice (ED15 values of 34 and 469 nmol/kg/day, respectively). T3 increased metabolic rate [whole body oxygen consumption (MVO2)] in both WT and TR alpha-/- mice, but the effect in the TR alpha 1-/- mice at the highest dose was half that of the WT mice. Thus, stimulation of MVO2 is likely due to both TR alpha and -beta. T3 had equivalent potency for cholesterol reduction in WT and TR alpha-/- mice. KB-141 increased MVO2 with selectivities of 16.5- and 11.2-fold vs. HR in WT and TR alpha 1-/- mice, respectively. KB-141 also increased MVO2 with a 10-fold selectivity and lowered cholesterol with a 27-fold selectivity vs. HR in rats. In primates, KB-141 caused significant cholesterol, lipoprotein (a), and body-weight reduction (up to 7% after 1 wk) with no effect on HR. TR beta-selective agonists may constitute a previously uncharacterized class of drugs to treat obesity, hypercholesterolemia, and elevated lipoprotein (a).

Thyroid receptor ligands. 1. Agonist ligands selective for the thyroid receptor beta1.

Endogenous thyroid receptor hormones 3,5,3',5'-tetraiodo-l-thyronine (T(4), 1) and 3,5,3'-triiodo-l-thyronine (T(3), 2) exert a significant effects on growth, development, and homeostasis in mammals. They regulate important genes in intestinal, skeletal, and cardiac muscles, the liver, and the central nervous system, influence overall metabolic rate, cholesterol and triglyceride levels, and heart rate, and affect mood and overall sense of well being. The literature suggests many or most effects of thyroid hormones on the heart, in particular on the heart rate and rhythm, are mediated through the TRalpha(1) isoform, while most actions of the hormones on the liver and other tissues are mediated more through the TRbeta(1) isoform of the receptor. Some effects of thyroid hormones may be therapeutically useful in nonthyroid disorders if adverse effects can be minimized or eliminated. These potentially useful features include weight reduction for the treatment of obesity, cholesterol lowering for treating hyperlipidemia, amelioration of depression, and stimulation of bone formation in osteoporosis. Prior attempts to utilize thyroid hormones pharmacologically to treat these disorders have been limited by manifestations of hyperthyroidism and, in particular, cardiovascular toxicity. Consequently, development of thyroid hormone receptor agonists that are selective for the beta-isoform could lead to safe therapies for these common disorders while avoiding cardiotoxicity. We describe here the synthesis and evaluation of a series of novel TR ligands, which are selective for TRbeta(1) over TRalpha(1). These ligands could potentially be useful for treatment of various disorders as outlined above. From a series of homologous R(1)-substituted carboxylic acid derivatives, increasing chain length was found to have a profound effect on affinity and selectivity in a radioreceptor binding assay for the human thyroid hormone receptors alpha(1) and beta(1) (TRalpha(1) and TRbeta(2)) as well as a reporter cell assay employing CHOK1-cells (Chinese hamster ovary cells) stably transfected with hTRalpha(1) or hTRbeta(1) and an alkaline phosphatase reporter-gene downstream thyroid response element (TRAFalpha(1) and TRAFbeta(1)). Affinity increases in the order formic, acetic, and propionic acid, while beta-selectivity is highest when the R(1) position is substituted with acetic acid. Within this series 3,5-dibromo-4-[(4-hydroxy-3-isopropylphenoxy)phenyl]acetic acid (11a) and 3,5-dichloro-4-[(4-hydroxy-3-isopropylphenoxy)phenyl]acetic acid (15) were found to reveal the most promising in vitro data based on isoform selectivity and were selected for further in vivo studies. The effect of 2, 11a, and 15 in a cholesterol-fed rat model was monitored including potencies for heart rate (ED(15)), cholesterol (ED(50)), and TSH (ED(50)). Potency for tachycardia was significantly reduced for the TRbeta selective compounds 11a and 15 compared with 2, while both 11a and 15 retained the cholesterol-lowering potency of 2. This left an approximately 10-fold therapeutic window between heart rate and cholesterol, which is consistent with the action of ligands that are approximately 10-fold more selective for TRbeta(1). We also report the X-ray crystallographic structures of the ligand binding domains of TRalpha and TRbeta in complex with 15. These structures reveal that the single amino acid difference in the ligand binding pocket (Ser277 in TRalpha or Asn331 in TRbeta) results in a slightly different hydrogen bonding pattern that may explain the increased beta-selectivity of 15.