Pharmacodynamic and pharmacogenomic study of the nanoparticle conjugate of camptothecin CRLX101 for the treatment of cancer

CRLX101 is a nanopharmaceutical consisting of cyclodextrin-based polymer molecule and camptothecin. The CRLX101 nanoparticle is designed to concentrate and slowly release camptothecin in tumors over an extended period of time. Tumor biopsy and blood samples collected from patients with advanced solid malignancies before and after CRLX101 treatment are subjected to immunohistochemistry and pharmacogenomics. The expression of Topoisomerase-1, Ki-67, CaIX, CD31 and VEGF decreased after CRLX101 treatment. The expressions of these proteins are inversely proportional with survival duration of the patients. The Drug Metabolism Enzymes and Transporters (DMET) array shows an allele frequency in patients similar to global populations with none of the SNPs associated with toxicity. The results suggest that the observed lower toxicity is not likely to be due to different genotypes in SNPs. CRLX101 demonstrates a promising anti-tumor activity in heavily pre-treated or treatment-refractory solid tumor malignancies presumably by inhibition of proliferation and angiogenesis correlating with tumor growth inhibition.From the Clinical EditorIn this cancer treatment study clinical samples collected from patients were subjected to immunohistochemistry and pharmacogenomics. The expressions of key proteins that are inversely proportional with survival duration of the patients decreased after treatment with CRLX101, a camptothecin slow-release nanoparticle conjugate. This anti-tumor activity in heavily pre-treated and treatment resistant solid tumors, promises a novel therapeutic approach.     

Preclinical study of the cyclodextrin-polymer conjugate of camptothecin CRLX101 for the treatment of gastric cancer

Camptothecin showed remarkable anticancer activity in animal models of cancer but was restricted in clinical use for its adverse toxicity in patients. The preclinical efficacy of CRLX101, a nanoparticle (NP) assembly containing cyclodextrin-based polymer and camptothecin was evaluated by in vitro cytotoxicity in gastric cancer cell lines and in vivo antitumor effects in human gastric cancer cell line BGC823 xenografts. Treated tumor sections were analyzed for presence of NPs and compared with vehicle control tumors for hypoxia and angiogenesis. Gastric cancer cell lines showed high in vitro cytotoxicity for CRLX101 and also showed strong antitumor activity in vivo. Electron micrographs revealed the intracellular presence of NPs in close proximity to vesicles. A significant decrease in expressions of carbonic anhydrase, VEGF, and CD31 proteins in treated tumors indicated an inhibition of hypoxia and angiogenesis. The results provide preclinical data for gastric adenocarcinoma. FROM THE CLINICAL EDITOR: This study describes a nanoparticle assembly containing cyclodextrin-based polymer and camptothecin, resulting in increased bioavailability of camptothecin, an effective but toxic anti-cancer agent. The antitumor effects and safety profile were demonstrated in a gastric carcinoma cell line.     

Design and development of IT-101, a cyclodextrin-containing polymer conjugate of camptothecin

IT-101 (Insert Therapeutics-101) is a linear, cyclodextrin-containing polymer conjugate of camptothecin (CPT). When formulated properly, the polymer conjugate self-assembles into nanoparticles of ca. 30 nm diameter and near neutral zeta potential. The nanoparticles show long circulation half-lives in animals and humans and localize in tumors. The nanoparticles enter the tumor cells and slowly release the CPT causing them to disassemble into individual polymer chains that are sufficiently small to be cleared renally. IT-101 is currently being investigated in human clinical trials. Here, the design and development of IT-101 is described with emphasis on features distinguishing it from other polymer-containing therapeutics.     

Antitumor activity of beta-cyclodextrin polymer-camptothecin conjugates

Antitumor activity of linear, beta-cyclodextrin polymer (CDP)-camptothecin (CPT) conjugates (HGGG6, LGGG10, HG6, and HGGG10) is investigated in nude mice bearing human LS174T colon carcinoma tumors. These conjugates differ in polymer molecular mass [97 kDa (H) or 35 kDa (L)], CDP-CPT linker structure [glycine (G) or triglycine (GGG)], and CPT loading [ca. 6 wt % (6) or 10 wt % (10)]. Maximum tolerable doses (MTDs) of the three conjugates, LGGG10, HG6, and HGGG10, are determined to be 36, 9, and 9 mg of CPT/kg, respectively, while the MTD of the CDP alone exceeds 240 mg/kg (highest value investigated). The three CDP-CPT conjugates with high polymer molecular masses (HGGG6, HG6, and HGGG10) demonstrate antitumor activity at their MTDs superior to that of CPT at the same amount and to that of irinotecan at its optimal dose. They also show tumor growth inhibition that is superior to that of the conjugate containing the low-molecular mass polymer (LGGG10) at the same dose of CPT. No significant effects of CPT weight loading or linker structure on tumor growth delay are observed. However, conjugates containing G appear to be less toxic than these with GGG. These antitumor studies demonstrate that the CDP-based conjugates of CPT exhibit tumor growth inhibition superior to that of CPT or irinotecan at the conditions employed in this study. The striking observation is that a short course of treatment with the polymer conjugates gives long-term control of tumor growth that does not occur with either CPT or irinotecan. Intracellular CDPs are demonstrated by analyzing cells that were cultured in the presence of rhodamine-labeled CDP (HRhod) containing medium using both confocal microscopy and flow cytometry. The long-term therapeutic efficacy of CDP-CPT conjugates observed in mice may in part be due to the sustained release of CPT from these conjugates in the acidic, intracellular compartments since these conjugates are shown to have significantly slower release rates at acidic pH than at physiological pH.     

MF101: a multi-component botanical selective estrogen receptor beta modulator for the treatment of menopausal vasomotor symptoms

INTRODUCTION: The Women's Health Initiative Estrogen Plus Progestin clinical trial demonstrated the risks exceeded the benefits which have led to a decline in menopausal hormone therapy (MHT) by greater than 50%. MHT use was initiated long before there was a significant understanding of the molecular mechanisms of estrogens. It has become clear that the problem with the current estrogens in MHT is they act non-selectively as an agonist in all tissues that contain estrogen receptors. MF101 is an oral, botanically derived extract that was designed to selectively regulate estrogen receptor beta (ERβ) because the increased risk of breast and endometrial cancer is due to the activation of estrogen receptor alpha (ERα) by estrogens. Preclinical and clinical data support a role for selective ERβ agonists, such as MF101, for vasomotor symptoms without increasing cancer risks. AREAS COVERED: The review covers the biological, pharmacological and clinical advantages of MF101, and the unique ability of MF101 to selectively target the ERβ pathway for the treatment of hot flashes (HF). EXPERT OPINION: Preclinical and clinical studies indicate that MF101, a selective estrogen receptor beta agonist, represents a new class of drugs that is safe and effective for treating HF and nighttime awakenings.     

2型糖尿病引起的疲劳与骨骼肌5-羟色胺降解的相关性研究

疲劳是2型糖尿病(T2DM)常见的并发症。本文研究了T2DM性疲劳与骨骼肌5-羟色胺(5-HT)系统的关系。动物实验用高脂饲料喂养结合腹腔注射链脲佐菌素建立小鼠T2DM模型,用5-HT_2A受体(5-HT_2AR)拮抗剂盐酸沙格雷酯(SH)及5-HT合成抑制剂卡比多巴(CDP)分别或联合给药治疗。细胞实验用D-葡萄糖、棕榈酸或5-HT刺激C2C12细胞。用SH、CDP或单胺氧化酶A(MAO-A)抑制剂氯吉兰分别抑制5-HT_2AR、5-HT合成及5-HT降解。本文中动物福利和实验过程均遵循中国药科大学动物伦理委员会的规定。结果表明,小鼠骨骼肌及C2C12细胞均存在5-HT_2AR、5-HT合成酶及MAO-A表达。T2DM以及棕榈酸、D-葡萄糖刺激C2C12细胞时,它们的表达明显上调,且棕榈酸是比D-葡萄糖更敏感的刺激它们表达的因子。转棒实验及生化指标检测均表明,T2DM性疲劳起因于骨骼肌5-HT_2AR、5-HT合成及5-HT降解的增加。5-HT_2AR通过介导MAO...     

SDS-aided immobilization and controlled release of camptothecin from agarose hydrogel.

Camptothecin (CPT), known to be an effective anticancer drug, has a limited therapeutic utility because of its poor water solubility. In this work, an approach has been made to overcome the limitation. CPT was first incorporated into the micelles formed from an ionic surfactant, sodium dodecyl sulfate (SDS) and the micellar drug aqueous solution was then used in preparation of the agarose hydrogel. It has been found that the presence of SDS greatly increased the solubility of CPT in water. For example, in 1 ml of 1.0 wt.% SDS water solution, 0.11 mg CPT could be solubilized (0.318 mM), which was 83 times the solubility in pure water. It was the hydrophobic cores of the SDS micelles that were able to accept the lipophilic drug to form stable drug-immobilized micelles. The formulation of a hydrogel using the drug-immobilized micelles has allowed us to obtain a unique and novel drug release system where the drug molecules are encapsulated by the micelles and the drug-containing micelles are dispersed in the gel network. The release of CPT from the so deliberately fabricated agarose hydrogel system has been studied as a function of surfactant concentration at 37 degrees C. The diffusion coefficients of CPT obtained by fitting to Fick's law ranged from 2.12 to 7.36 x 10(-7)cm(2)s(-1). The results showed that SDS prolonged the drug release by reducing the diffusion coefficient of CPT in the gel.     

TSG101蛋白在HIV-1出芽过程中的作用及其抑制剂

tsg101基因是一个抑制肿瘤基因，其翻译产物TSG101蛋白具有多重生物学功能。近年来的研究发现，TSG101蛋白通过与HIV-1 Gag蛋白结合，辅助HIV-1病毒颗粒从被感染细胞中释放出来，这说明TSG101可作为一个新的抗HIV-1靶点。基于TSG101蛋白与HIV Gag的相互作用和结构，研究人员设计合成了几类TSG101蛋白抑制剂，并通过测定这些抑制剂对TSG101蛋白的亲和力，发现其中某些化合物具有比野生型Gag更强的TSG101蛋白亲和力，值得进一步研究。     

A randomized cross-over trial to define neurophysiological correlates of AV-101 N-methyl-d-aspartate receptor blockade in healthy veterans

The kynurenine pathway (KP) is a strategic metabolic system that combines regulation of neuronal excitability via glutamate receptor function and neuroinflammation via other KP metabolites. This pathway has great promise in treatment of depression and suicidality. The KP modulator AV-101 (4-chlorokynurenine, 4-Cl-KYN), an oral prodrug of 7-chlorokynurenic acid (7-Cl-KYNA), an N-methyl-d-aspartate receptor (NMDAR) glycine site antagonist, and of 4-chloro-3-hydroxyanthranilic acid (4-Cl-3-HAA), a suppressor of NMDAR agonist quinolinic acid (QUIN), is a promising potential antidepressant that targets glutamate functioning via the KP. However, a recent placebo-controlled clinical trial of AV-101 in depression found negative results. This raises the question of whether AV-101 can penetrate the brain and engage the NMDAR and KP effectively. To address this problem, ten healthy US military veterans (mean age = 32.6 years ± 6.11; 1 female) completed a phase-1 randomized, double-blind, placebo-controlled, crossover study to examine dose-related effects of AV-101 (720 and 1440 mg) on NMDAR engagement measured by γ-frequency band auditory steady-state response (40 Hz ASSR) and resting EEG. Linear mixed models revealed that 1440 mg AV-101, but not 720 mg, increased 40 Hz ASSR and 40 Hz ASSR γ-inter-trial phase coherence relative to placebo. AV-101 also increased 4-Cl-KYN, 7-Cl-KYNA, 4-Cl-3-HAA, 3-HAA, and KYNA in a dose-dependent manner, without affecting KYN and QUIN. AV-101 was safe and well tolerated. These results corroborate brain target engagement of 1440 mg AV-101 in humans, consistent with blockade of interneuronal NMDAR blockade. Future studies should test higher doses of AV-101 in depression. Suicidal behavior, which has been associated with high QUIN and low KYNA, is also a potential target for AV-101.Subject terms: Biomarkers, Neurophysiology, Neuroscience     

XMT-1001, a novel polymeric camptothecin pro-drug in clinical development for patients with advanced cancer

An overview of XMT-1001 is provided in the context of other topoisomerase I inhibitors conjugated to polymers or encapsulated in liposomes. XMT-1001 is a novel polymeric pro-drug derivative of camptothecin (CPT) with a molecular weight of 70 kDa, in which CPT is chemically tethered to a hydrophilic, biodegradable polyacetal polymer, poly(1-hydroxymethylethylene hydroxymethylformal), also called PHF or Fleximer®. XMT-1001 releases CPT via intermediates camptothecin-20-O-(N-succinimidoglycinate) (CPT-SI), and camptothecin-20-O-(N-succinamidoyl-glycinate) (CPT-SA) over an extended time period. XMT-1001 has an improved therapeutic window compared to CPT and irinotecan in human tumor xenograft models, providing a compelling rationale for clinical development. A unique feature of XMT-1001 is its dual phase release mechanism for CPT which may result in lower levels of CPT in the urine and less bladder toxicity, a serious dose limiting toxicity associated with CPT and CPT conjugated to other polymers. XMT-1001 is being evaluated in patients with advanced cancer in an ongoing Phase 1 trial.     

Enhancement of the effects of a complete inhibitor of enkephalin-catabolizing enzymes, RB 101, by a cholecystokinin-B receptor antagonist in diabetic rats

1. RB 101, a complete inhibitor of enkephalin-catabolizing enzymes, has been previously shown to produce antinociception in normal rats after systemic administration. Moreover, its coadministration with a cholecystokinin-B (CCK-B) receptor antagonist has been shown to strongly enhance its antinociceptive effect in normal rats. In this work, we determined whether RB 101 was able to reduce hyperalgesia and allodynia in diabetic rats, a model of neuropathic pain. The type of opioid receptors (mu or delta) involved was determined using naloxone and naltrindole, respectively, and the interactions between endogenous enkephalins and CCK on nociception control was investigated using coadministration of RB 101 and the CCK-B receptor antagonist CI-988. 2. RB 101 suppressed mechanical hyperalgesia (paw pressure-induced vocalization test), partially alleviated mechanical allodynia (von Frey hair test), and was ineffective in thermal allodynia (tail immersion test). The analgesic effect was completely cancelled by naloxone or naltrindole, suggesting that is requires the availability of mu- and/or delta-opioid receptors. 3. The combination of an inactive dose of CI-988 with the lowest effective dose of RB 101 resulted in a stronger increase in the vocalization threshold comparatively to RB 101 alone. 4. The present study demonstrates that the antinociception generated by RB 101 induced by elevation of extracellular levels of endogenous enkephalins, can be extended to neuropathic pain in diabetic rats and that blockade of CCK-B receptors potentiated antinociceptive effects elicited by RB 101.     

First‐in‐human,phase I/IIa study of CRLX301, a nanoparticle drug conjugate containing docetaxel,in patients with advanced or metastatic solid malignancies

Investigational New Drugs - Background This was a phase I/IIa study to investigate the tolerability, efficacy and pharmacokinetics (PK)/ pharmacodynamics (PD) of CRLX301, CDP-based nanoparticle...     

Effect of gomisin A (TJN-101) on the arachidonic acid cascade in macrophages

It has been reported that leukotrienes (LTs) may play a role in inflammatory liver diseases, and several inhibitors of LTs show an inhibitory effect on experimental liver injuries. In this study, the effect of Gomisin A (TJN-101), which is a lignan component of schisandra fruits, on the arachidonic acid cascade in macrophages was examined to explain the mechanisms of the inhibitory effect of TJN-101 on liver injuries. The production of leukotriene B4 was suppressed by treatment with TJN-101, while the activity of 5-lipoxygenase was not affected. The release of arachidonic acid from macrophages stimulated with fMet-Leu-Phe or the Ca++ ionophore A23187 was suppressed by treatment with TJN-101. The activity of phospholipase A2 was not affected by treatment with TJN-101. These results suggested that TJN-101 produces an inhibitory effect on the biosynthesis of LTs by preventing the release of arachidonic acid, and it was thought that the preventive effect on the arachidonic acid cascade may be partially associated with the inhibitory effect of TJN-101 on liver injuries.     

Organic anion-transporting polypeptide 1a4–mediated heterogeneous distribution of sulforhodamine-101 in rat hepatic lobules

It has been known that organic anion-transporting polypeptides (Oatps) involve hepatic transports several organic anionic compounds and drugs. This study aimed to investigate sulforhodamine-101 (SR-101) distribution in the rat liver, determine the molecules responsible for the distribution, and delineate the manner of distribution. After intravenous SR-101 administration, its distribution in frozen rat hepatic sections was examined. SR-101-derived signals were detected in regions around the hepatic central vein (CV), where immunohistochemistry (IHC) indicated high Oatp1a4 expression. The signals decreased with treatment by digoxin, a specific substrate for Oatp1a4. In vitro studies using isolated rat hepatocytes and rat Oatp1a4-expressing Xenopus laevis oocytes have suggested that SR-101 is an Oatp1a4 substrate and is taken up into rat hepatocytes mainly via Oatp1a4. Therefore, results suggested SR-101 zonation because of Oatp1a4 involvement and that Oatp1a4 function is dominant in the region around the hepatic CV in rat hepatic lobules.     

Application of LC/MS/MS in the quantitation of SU101 and SU0020 uptake by 3T3/PDGFr cells

SU101 or leflunomide, has been studied extensively because of its anti-cancer and immunomodulating properties. The parent isoxazole compound is converted in vitro and metabolized in vivo to an open ring isomeric form, SU0020. Several pharmacological activities have been reported for the parent and metabolite compounds including inhibition of platelet-derived growth factor (PDGF)-mediated signaling for the parent compound and inhibition of de novo pyrimidine biosynthesis for the metabolite. The inhibition of PDGF-mediated signaling and the anti-tumor properties have been ascribed to the parent compound. In spite of its short plasma half-life of the parent molecule, SU101 can be administered intermittently in animal tumor models and retain efficacy. Therefore, the relationship between plasma levels of SU101 and its efficacy in tumor-implanted immuno-compromised mice is not well established. This study was conducted to assess the concentration of SU101 in 3T3/PDGFr alpha and beta cells (NIH3T3 mouse fibroblasts engineered to overexpress human PDGFr alpha or beta) to better understand the cellular levels of SU101 and SU0020. Two strains of 3T3/PDGFr cells (alpha and beta) were incubated with 1, 25, and 100 microM concentrations of SU101 for 1, 6, 24, and 48 hours. Quantitation of SU101 and SU0020 in these cell lines was achieved by a specific and sensitive liquid chromatography-tandem mass spectrometry (LC/MS/MS) method. Interestingly, in both alpha and beta cell lysates SU101 was much more concentrated than SU0020. The greater concentration of SU101 versus SU0020 that was observed may be due to the preferential partitioning of SU101 into the cells and this shows that significant levels of the parent drug can reach the pharmacological site of action for inhibition of PDGF receptors. The data suggest that the conversion of SU101 to SU0020 is much slower in these cells than in the incubation media.     

Therapeutic effects of Lactobacillus paracasei subsp. paracasei NTU 101 powder on dextran sulfate sodium-induced colitis in mice

Ulcerative colitis (UC) is a form of inflammatory bowel disease (IBD) whose exact cause is still unclear. Disruption of the intestinal microflora is considered one of the main causes of the disease. Lactobacillus paracasei subsp. paracasei NTU 101 (NTU 101) is a multifunctional strain that has been shown in previous studies to possess anti-inflammatory properties and to exert a modulatory effect on intestinal bacteria associated with certain pathogenic mechanisms of IBD. In the current study, we investigated the effects of NTU 101 on dextran sulfate sodium (DSS)-induced colitis in a mouse model. Colitis was induced in male C57BL/6 mice (total number n = 60) via dissolved DSS in drinking water on days 15–21 of the experiment. The effects of continuous 25 d feeding (days 0–25) of either a half or a full dose [2.3 × 10⁹ colony-forming units (CFU)/kg body weight (BW)/d and 4.5 × 10⁹ CFU/kg BW/d, respectively] of NTU 101 was evaluated. Lactobacillus rhamnosus BCRC 16000 (BCRC 16000) and L. paracasei subsp. paracasei BCRC 14023 (BCRC 14023) strains were given to control groups. The results indicated that NTU 101 powder improved anti-oxidant capacity, reduced pro-inflammatory cytokine levels, increased anti-inflammatory cytokine levels, and slightly ameliorated body weight loss in DSS-treated mice during the final days of the study. This indicated that NTU 101 powder can relieve the clinical symptoms of DSS-induced colitis in mice.     

Behavioral and neurobiological effects of the enkephalinase inhibitor RB101 relative to its antidepressant effects

Nonpeptidic delta-opioid receptor agonists produce antidepressant-like effects in rodents, and compounds that inhibit the breakdown of endogenous opioid peptides have antidepressant-like effects in animal models. In this study, the behavioral effects of the enkephalinase inhibitor, RB101 (N-[(R, S)-2-benzyl-3-[(S)(2-amino-4-methyl-thio)-butyldithio]-1-oxopropyl]-l-phenylalanine benzyl ester), were examined. Specifically, the effects of RB101 on convulsive activity, locomotor activity, and antidepressant-like effects in the forced swim test were studied in Sprague-Dawley rats, and the opioid receptor types mediating these effects were examined by antagonist studies. In addition, the effects of RB101 on brain-derived neurotrophic factor (BDNF) mRNA expression were evaluated in relation to its antidepressant effects. RB101 produced delta-opioid receptor-mediated antidepressant effects (32 mg/kg i.v. and 100 mg/kg i.p.) and increased locomotor activity (32 mg/kg i.v.) in rats. RB101 did not produce convulsions or seizures and did not alter BDNF mRNA expression. In conclusion, RB101 has the potential to produce antidepressant effects without convulsions.