Search

Whether glucose is predominantly metabolized via oxidative phosphorylation or glycolysis differs between quiescent versus proliferating cells, including tumor cells. However, how glucose metabolism is coordinated with cell cycle in mammalian cells remains elusive. Here, we report that mammalian cells predominantly utilize the tricarboxylic acid (TCA) cycle in G1 phase, but prefer glycolysis in S phase. Mechanistically, coupling cell cycle with metabolism is largely achieved by timely destruction of IDH1/2, key TCA cycle enzymes, in a Skp2-dependent manner. As such, depleting SKP2abolishes cell cycle-dependent fluctuation of IDH1 protein abundance, leading to reduced glycolysis in S phase. Furthermore, elevated Skp2 abundance in prostate cancer cells destabilizes IDH1 to favor glycolysis and subsequent tumorigenesis. Therefore, our study reveals a mechanistic link between two cancer hallmarks, aberrant cell cycle and addiction to glycolysis, and provides the underlying mechanism for the coupling of metabolic fluctuation with periodic cell cycle in mammalian cells.

One approach to creating more beneficial therapeutic antibodies is to develop bispecific antibodies (bsAbs), particularly IgG-like formats with tetravalency, which may provide several advantages such as multivalent binding to each target antigen. Although the effects of configuration and antibody-fragment type on the function of IgG-like bsAbs have been studied, there have been only a few detailed studies of the influence of the variable fragment domain order. Here, we prepared four types of hEx3-scDb-Fc, IgG-like bsAbs, built from a single-chain hEx3-Db (humanized bispecific diabody [bsDb] that targets epidermal growth factor receptor and CD3), to investigate the influence of domain order and fusion manner on the function of a bsDb with an Fc fusion format. Higher cytotoxicities were observed with hEx3-scDb-Fcs with a variable light domain (VL)–variable heavy domain (VH) order (hEx3-scDb-Fc-LHs) compared with a VH–VL order, indicating that differences in the Fc fusion manner do not affect bsDb activity. In addition, flow cytometry suggested that the higher cytotoxicities of hEx3-scDb-Fc-LH may be attributable to structural superiority in cross-linking. Interestingly, enhanced degradation resistance and prolonged in vivo half-life were also observed with hEx3-scDb-Fc-LH. hEx3-scDb-Fc-LH and its IgG2 variant exhibited intense in vivo antitumor effects, suggesting that Fc-mediated effector functions are dispensable for effective anti-tumor activities, which may cause fewer side effects. Our results show that merely rearranging the domain order of IgG-like bsAbs can enhance not only their antitumor activity, but also their degradation resistance and in vivo half-life, and that hEx3-scDb-Fc-LHs are potent candidates for next-generation therapeutic antibodies.

Background: There is an urgent need for early diagnosis and treatment of dementia to ease caregiver burden and medical costs associated with the increasing number of affected patients. Molecular imaging with target-specific ligands is contributing to the early diagnosis of dementia and the evaluation of anti-dementia therapy. Objective: This article reviews recent advances in the molecular imaging field applied to dementia. To illustrate the utility of molecular imaging in the clinical management of dementia, results from recently published papers using new imaging probes are compared with those from conventional imaging strategies. Conclusion: The recent development of β-sheet binding agents including FDDNP, PIB, SB-13, BF-227 and BAY94-9172 enables the non-invasive detection of amyloid deposition in the brain. These agents would be useful for the early and accurate diagnosis of Alzheimer's disease, patient selection for disease-modifying therapeutic trials and monitoring the effect of anti-amyloid therapy. Also, monitoring neurotransmitter function contributes to the differential diagnosis of dementia and refinement of treatment protocols. New targets for molecular imaging are focusing on protein misfolding diseases associated with the neurotoxic deposition of aggregated tau, α-synuclein and prion proteins.

Progressive deposition of amyloid plaques in the brain, which begins before the appearance of cognitive decline, is an initiating event in the pathogenesis of Alzheimers disease. Therefore, noninvasive detection of amyloid pathology is important for presymptomatic diagnosis and preventive therapy for Alzheimers disease. Recent research advances have enabled the in vivo imaging of amyloid pathology in humans using nuclear medicine technology. Several amyloid-binding agents have been developed and evaluated by positron emission tomography (PET) and single photon emission computed tomography (SPECT) for their use as contrast agents. Available clinical evidence indicates that amyloid imaging enables the early diagnosis of Alzheimers disease with high accuracy and suggests its usefulness for the prediction of progression to Alzheimers disease in subjects with mild cognitive impairment and probably also in cognitively normal individuals. Another application of this technology is as a surrogate marker for monitoring brain amyloid. In this review, we describe recent progress in the development of amyloid imaging technology and human clinical trials.

Excessive amyloid-β (Aβ) deposition in the brain is one of the most crucial events in the early pathological stage of Alzheimer's disease (AD). Therefore, Aβ deposits have enough potential to become a useful biomarker for not only an early diagnosis of AD, but also for the assessment of the clinical efficacy of anti-Aβ therapies, if they can be measured non-invasively and reliably in living patients. As a potent candidate technique to measure this biomarker, PET amyloid imaging using a radioligand for Aβ deposits has received much attention. A large number of Aβ ligands have been synthesized and evaluated as candidates for amyloid imaging agents. These can be classified into six categories of derivatives: Congo-red, Thioflavine T, stilbene, vinylbenzoxazole, DDNP, and miscellaneous. Many of these derivatives exhibit high binding affinities to Aβ fibrils (below 20 nM) and some of them also show excellent brain pharmacokinetic profiles. The concept of amyloid imaging is currently being tested in human PET studies using optimized amyloid imaging agents. Despite the small number of subjects, these studies have demonstrated sufficiently promising results. This review article provides an overview of recent advances in the development of amyloid imaging agents, and includes: a summary of the fundamental basis and clinical significance of amyloid imaging; lists of binding affinity data for 135 compounds classified into 12 molecular frameworks; a comprehensive discussion of the in vitro and in vivo features of representative Aβ ligands; and a discussion of the current state of clinical evaluation of these amyloid imaging agents (PIB, SB-13, BF-227, and FDDNP).

Two positron-emitting analogues of tyrosine, O-[¹¹C]methyl-L-tyrosine and O-[¹⁸F]fluoromethyl-L-tyrosine were prepared as new tumor imaging agents. The alkylating agent, [¹¹C]methyl triflate or [¹⁸F]fluoromethyl triflate, was simply bubbled through a dimethylsulfoxide solution of L-tyrosine disodium salt at room temperature. After subsequent HPLC purification the labeled L-tyrosine analogues were obtained in decay-corrected radiochemical yields of over 50%, based on their corresponding labeling agent, with radiochemical purities always higher than 98%. The quite straightforward preparation, together with the high radiochemical yields achieved, make both these syntheses suitable for routine production. Copyright © 2003 John Wiley & Sons, Ltd.

Matrix metalloproteinases (MMPs) are key enzymes involved in cancer invasion and metastasis. New ¹⁸F-labeled MMP inhibitors (1a–c) has been designed and synthesized for cancer imaging by positron emmision tomography. The precursors were synthesized in four steps starting from D-form of amino acids. Radiosynthesis of 1a–c were carried out by simple one-pot synthesis. The resulting radiofluorinated MMP inhibitors were obtained in overall radiochemical yields of 13–43% (EOB, decay corrected) within 60–70 min (including final preparative HPLC separation). Copyright © 2002 John Wiley & Sons, Ltd.

An improved approach to the synthesis of 1-O-(8-[¹⁸F]fluorooctanoyl)-2-O-palmitoyl-rac-glycerol (rac-1,2-[¹⁸F]FDAG) has been developed. We designed and synthesized two new types of precursors for the radiosynthesis and investigated their general utility. Each precursor was smoothly radiofluorinated (5 min) and the protecting group at the 3-O-position was rapidly removed (1 min). The resulting rac-1,2-[¹⁸F]FDAG was obtained in overall radiochemical yields of 20–30% (EOB) within 70 min including final preparative HPLC separation. Copyright © 2000 John Wiley & Sons, Ltd.

A 4-nitrothiophenol (4-NTP, Ar-NO₂) modified electrode was prepared by dipping a gold electrode into a 4-NTP/dichloromethane solution (self-assembly method). The redox response of the electrode depended on the reduction stages of the nitro group in the 4-NTP molecule. When the 4-NTP on the electrode was partially reduced to 4-hydroxylaminothiophenol (Ar-NHOH) at -0.2 to -0.3 V vs SCE (the potential depends on the pH of the electrolyte solution), the electrode showed a pair of redox responses in an acidic aqueous solution. The responses are attributed to the redox cycling between 4-nitrosothiophenol (Ar-NO) and Ar-NHOH with two-electron and two-proton transfer. Copyright 1995, 1999 Academic Press

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

WITH the purpose of mapping representations of the finger and proximal arm in the human primary motor cortex (MI), we measured regional cerebral blood flow (rCBF) in eight right-handed normal volunteers during self-paced finger and proximal arm movements. Each movement activated two-different fields in MI, one located deep in the anterior lip of the central sulcus and the other relatively close to the surface of the precentral gyrus. Arm fields were located higher than finger fields. A superficial arm field and a deep finger field partially, overlapped. The results indicate that there are two spatially separate motor representations of the finger and proximal arm in the human MI.