Replacement Dose for Overt Hypothyroidism induced by Programmed Cell Death Protein 1 Antibodies.

BACKGROUND: The present recommendations, consensus, or guidelines for the replacement dosage for hypothyroidism induced by programmed cell death protein 1 (PD-1) therapy are not uniform, and there are very few special clinical trials that have examined the replacement dosage for it. OBJECTIVES: This article illustrates the clinical characteristics of hypothyroidism induced by PD-1 antibodies (Abs) and reports the recommended replacement dosage for hypothyroidism. METHODS: Eighteen patients with overt primary hypothyroidism induced by PD-1 Abs (group 1) were selected from 655 patients with different tumor types. Retrospective analysis was performed on patients in group 1 and 18 patients with natural courses of overt primary hypothyroidism who were age- and sex-matched with the patients in group 1 (group 2). The replacement dosages required for the patients in the two groups were compared. RESULTS: Thyroid dysfunction occurred in group 1 after approximately 3.0±1.4 cycles of PD-1 therapy (1-6 stages), with a median time of 61.5 days. The median time of onset of hypothyroidism among all patients was 87.5 days (30-240 days). Most of the patients with hypothyroidism were asymptomatic, and the onset of hypothyroidism was independent of age, sex, TPOAb, TgAb and TSH in group 1 (P>0.05). The average replacement dosage for patients in group 1 was 1.80.6 µg/kg/d (0.6-3.2 µg/kg/d). Multiple linear regression analysis showed that sex, age, TPOAb, TgAb and TSH were not correlated with drug dosage. CONCLUSION: It seemed that the average maintenance dosage of levothyroxine might need to be 1.8 µg/kg/day for patients with overt hypothyroidism induced by PD-1 Abs.

Unveiling the advantages of an ultrathin N-doped carbon shell on self-supported tungsten phosphide nanowire arrays for the hydrogen evolution reaction experimentally and theoretically.

Packaging electrocatalysts with carbon shells offers an opportunity to develop stable and effective hydrogen evolution reaction (HER) materials. Here, an ultrathin N-doped carbon-coated self-supported WP nanowire array (WP@NC NA) hybrid has been synthesized. Owing to the encapsulation of the ultrathin N-doped carbon shell on the WP surface, the as-prepared WP@NC NA hybrid exhibits enhanced physicochemical stability, more active sites, and superior conductivity compared with WP NA without carbon coating. Besides, density functional theory calculations demonstrate that the carbon shell can optimize the hydrogen adsorption step in the acidic HER, and simultaneously facilitate water physical adsorption, water dissociation, and hydroxyl group desorption steps during the alkaline HER. These findings demonstrate the intrinsic mechanism of how a carbon shell promotes the acidic and alkaline HER kinetics, and provide scientific guidance for the packaging design of promising carbon-encapsulating self-supported electrocatalysts.

[Progress in the mechanisms of response to different oxygen concentrations in Caenorhabditis elegans].

Oxygen levels are unequal in different living geographical locations of human and related to normal physiology of health. The reduction of oxygen level in the body can lead to a variety of diseases, such as stroke caused by cerebral ischemia and hypoxia. In the recent years, many studies have elucidated the molecular and cellular mechanisms of organism response to different oxygen concentrations by using the nematode Caenorhabditis elegans (C. elegans) as model organism. C. elegans can escape hypoxia or hyperoxia and adapt to the ambient oxygen environments, and there are different response and regulation mechanisms in different degrees of hypoxia environment. In this paper, recent advances in the reaction of nematodes to different oxygen concentrations and the underlying mechanism were reviewed.

A novel COL10A1 mutation in a Chinese pedigree with Schmid type metaphyseal chondrodysplasia.

BACKGROUND: Schmid type metaphyseal chondrodysplasia (MCDS) is a kind of autosomal inherited epiphyseal dysplasia caused by a mutation of the COL10A1 gene. Clinical expression of this mutation includes a waddling gait, coxa vara, genu varus or genu valgus and shortened lower limbs among others. To date, over 40 kinds of heterozygous mutations have been identified in the collagen domain of COL10A1 but data on family pedigrees for these is lacking. METHODS: Nineteen people without a history of interbreeding were selected for the three generations pedigree of MCDS. The proband is a 13 year-old boy with short limbs, hip varus, and tibial varus. In this group, seven people had MCDS (two men, five women). Blood samples for DNA extraction and mutational analysis were collected to sequence the CLO10A1 gene. RESULTS: Chromas atlas analysis and monoclonal sequencing revealed that 7 of the patients in the family are missing a C nucleotide in the third exon of the COL10A1 gene (c.2005delC). CONCLUSIONS: The COL10A1 gene mutation results in a frameshift mutation from codon 669, the substitution of 7 amino acids, and premature termination of expression (p.his669thrfsX8). In contrast to the other mutations identified, c.2005delC is close to the C-terminus of the protein sequence and may result in genetic heterogeneity of the Chinese population.

Lead optimization of methionine aminopeptidase-2 (MetAP2) inhibitors containing sulfonamides of 5,6-disubstituted anthranilic acids.

A series of aryl sulfonamides of 5,6-disubstituted anthranilic acids were identified as potent inhibitors of methionine aminopeptidase-2 (MetAP2). Small alkyl groups and 3-furyl were tolerated at the 5-position of anthranilic acid, while -OCH(3), CH(3), and Cl were found optimal for the 6-position. Placement of 2-aminoethoxy group at the 6-position enabled interaction with the second Mn(2+) but did not result in enhancement in potency. Introduction of a tertiary amino moiety at the ortho-position of the sulfonyl phenyl ring gave reduced protein binding and improved cellular activity, but led to lower oral bioavailability.

Discovery and optimization of anthranilic acid sulfonamides as inhibitors of methionine aminopeptidase-2: a structural basis for the reduction of albumin binding.

Methionine aminopeptidase-2 (MetAP2) is a novel target for cancer therapy. As part of an effort to discover orally active reversible inhibitors of MetAP2, a series of anthranilic acid sulfonamides with micromolar affinities for human MetAP2 were identified using affinity selection by mass spectrometry (ASMS) screening. These micromolar hits were rapidly improved to nanomolar leads on the basis of insights from protein crystallography; however, the compounds displayed extensive binding to human serum albumin and had limited activity in cellular assays. Modifications based on structural information on the binding of lead compounds to both MetAP2 and domain III of albumin allowed the identification of compounds with significant improvements in both parameters, which showed good cellular activity in both proliferation and methionine processing assays.

Development of sulfonamide compounds as potent methionine aminopeptidase type II inhibitors with antiproliferative properties.

We have screened molecules for inhibition of MetAP2 as a novel approach toward antiangiogenesis and anticancer therapy using affinity selection/mass spectrometry (ASMS) employing MetAP2 loaded with Mn(2+) as the active site metal. After a series of anthranilic acid sulfonamides with micromolar affinities was identified, chemistry efforts were initiated. The micromolar hits were quickly improved to potent nanomolar inhibitors by chemical modifications guided by insights from X-ray crystallography.

3-Amino-2-hydroxyamides and related compounds as inhibitors of methionine aminopeptidase-2.

Substituted 3-amino-2-hydroxyamides and related hydroxyamides and acylhydrazines were identified as inhibitors of human methionine aminopeptidase-2 (MetAP2). Examination of substituents through parallel synthesis and iterative structure-based design allowed the identification of potent inhibitors with good selectivity against MetAP1. Diacylhydrazine 3t (A-357300) was identified as an analogue displaying inhibition of methionine processing and cellular proliferation in human microvascular endothelial cells (HMVEC).

Tumor suppression by a rationally designed reversible inhibitor of methionine aminopeptidase-2.

Methionine aminopeptidase (MetAP)-2 has been suggested as a novel target for cancer therapy because the anticancer agent TNP-470 irreversibly inactivates the catalytic activity of this enzyme. However, the importance of MetAP2 in cell growth and tumor progression was uncertain because previous data were based on the chemically reactive TNP-470. Here we show that a rationally designed reversible MetAP2 inhibitor, A-357300, suppresses tumor growth preclinically without the toxicities observed with TNP-470. We have synthesized this bestatin-type MetAP2 inhibitor with the aid of crystal structures of the enzyme-inhibitor complexes and parallel synthesis. A-357300 induces cytostasis by cell cycle arrest at the G(1) phase selectively in endothelial cells and in a subset of tumor cells, but not in most primary cells of nonendothelial type. A-357300 inhibits angiogenesis both in vitro and in vivo and shows potent antitumor efficacy in carcinoma, sarcoma, and neuroblastoma murine models. These data affirm that MetAP2 plays a pivotal role in cell growth and establish that reversible MetAP2 inhibitors are promising novel cancer therapeutic agents.

Physiologically relevant metal cofactor for methionine aminopeptidase-2 is manganese.

The identity of the physiological metal cofactor for human methionine aminopeptidase-2 (MetAP2) has not been established. To examine this question, we first investigated the effect of eight divalent metal ions, including Ca(2+), Co(2+), Cu(2+), Fe(2+), Mg(2+), Mn(2+), Ni(2+), and Zn(2+), on recombinant human methionine aminopeptidase apoenzymes in releasing N-terminal methionine from three peptide substrates: MAS, MGAQFSKT, and (3)H-MASK(biotin)G. The activity of MetAP2 on either MAS or MGAQFSKT was enhanced 15-25-fold by Co(2+) or Mn(2+) metal ions in a broad concentration range (1-1000 microM). In the presence of reduced glutathione to mimic the cellular environment, Co(2+) and Mn(2+) were also the best stimulators (approximately 30-fold) for MetAP2 enzyme activity. To determine which metal ion is physiologically relevant, we then tested inhibition of intracellular MetAP2 with synthetic inhibitors selective for MetAP2 with different metal cofactors. A-310840 below 10 microM did not inhibit the activity of MetAP2-Mn(2+) but was very potent against MetAP2 with other metal ions including Co(2+), Fe(2+), Ni(2+), and Zn(2+) in the in vitro enzyme assays. In contrast, A-311263 inhibited MetAP2 with Mn(2+), as well as Co(2+), Fe(2+), Ni(2+), and Zn(2+). In cell culture assays, A-310840 did not inhibit intracellular MetAP2 enzyme activity and did not inhibit cell proliferation despite its ability to permeate and accumulate in cytosol, while A-311263 inhibited both intracellular MetAP2 and proliferation in a similar concentration range, indicating cellular MetAP2 is functioning as a manganese enzyme but not as a cobalt, zinc, iron, or nickel enzyme. We conclude that MetAP2 is a manganese enzyme and that therapeutic MetAP2 inhibitors should inhibit MetAP2-Mn(2+).

Paclitaxel at ultra low concentrations inhibits angiogenesis without affecting cellular microtubule assembly.

Many conventional chemotherapeutics, such as the microtubule-stabilizing anticancer drug paclitaxel (Taxol), have been shown to have anti-angiogenic activity and clinical application of a continuous low dose of these agents has been suggested for cancer therapy. In this study, we show that paclitaxel selectively inhibits the proliferation of human endothelial cells (ECs) at ultra low concentrations (0.1-100 pM), with an IC50 = 0.1 pM, while it inhibits non-endothelial type human cells at 10(4) - to 10(5) -fold higher concentrations, with IC50 = 1-10 nM. The selectivity of paclitaxel inhibition of cell proliferation is also species specific, as mouse ECs are not sensitive to paclitaxel at ultra low concentrations. They are inhibited by higher concentrations of paclitaxel with IC50 = 1-10 nM. Inhibition of human ECs by paclitaxel at ultra low concentrations does not affect the cellular microtubule structure, and the treated cells do not show G2/M cell cycle arrest and apoptosis, suggesting a novel but as yet unidentified mechanism of action. In an in vitro angiogenesis assay, paclitaxel at ultra low concentrations blocks human ECs from forming sprouts and tubes in the three-dimensional fibrin matrix. In summary, paclitaxel selectively inhibits human EC proliferation and in vitro angiogenesis at low picomolar concentrations. The data support a clinical application of continuous ultra-low-dose paclitaxel to treat cancer.