Rociletinib (CO-1686) enhanced the efficacy of chemotherapeutic agents in ABCG2-overexpressing cancer cells in vitro and in vivo

Overexpression of adenosine triphosphate (ATP)-binding cassette subfamily G member 2 (ABCG2) in cancer cells is known to cause multidrug resistance (MDR), which severely limits the clinical efficacy of chemotherapy. Currently, there is no FDA-approved MDR modulator for clinical use. In this study, rociletinib (CO-1686), a mutant-selective epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI), was found to significantly improve the efficacy of ABCG2 substrate chemotherapeutic agents in the transporter-overexpressing cancer cells in vitro and in MDR tumor xenografts in nude mice, without incurring additional toxicity. Mechanistic studies revealed that in ABCG2-overexpressing cancer cells, rociletinib inhibited ABCG2-mediated drug efflux and increased intracellular accumulation of ABCG2 probe substrates. Moreover, rociletinib, inhibited the ATPase activity, and competed with [¹²⁵I] iodoarylazidoprazosin (IAAP) photolabeling of ABCG2. However, ABCG2 expression at mRNA and protein levels was not altered in the ABCG2-overexpressing cells after treatment with rociletinib. In addition, rociletinib did not inhibit EGFR downstream signaling and phosphorylation of protein kinase B (AKT) and extracellular signal-regulated kinase (ERK). Our results collectively showed that rociletinib reversed ABCG2-mediated MDR by inhibiting ABCG2 efflux function, thus increasing the cellular accumulation of the transporter substrate anticancer drugs. The findings advocated the combination use of rociletinib and other chemotherapeutic drugs in cancer patients with ABCG2-overexpressing MDR tumors.     

萆苓祛痛方对糖尿病痛风大鼠骨骼肌组织SIRT3蛋白表达及URAT1 mRNA的影响

目的:探讨萆苓祛痛方对糖尿病痛风大鼠骨骼肌组织去乙酰化酶3(SIRT3)蛋白表达及尿酸盐转运体1(URAT1) mRNA的影响。方法:选择健康雄性大鼠40只,除正常组外,其余组予高脂饲料喂养并联合小剂量链脲佐菌素(STZ)溶液40 mg·kg-1腹腔注射1次,以血糖≥16. 7 mmol·L-1,为糖尿病模型。4 d后关节腔注射5%尿酸钠溶液1次,诱导痛风模型,模型成功后,分为萆苓祛痛方组(萆苓组,10 g·kg-1),吲哚美辛组(5 mg·kg-1),吡格列酮组(10 mg·kg-1),均连续给药21 d,正常组、模型组予等量生理盐水;采用蛋白免疫印迹法(Western blot)测定骨骼肌组织SIRT3蛋白表达;实时荧光定量聚合酶链式反应(Real-time PCR)检测骨骼肌组织URAT1 mRNA表达,并进行病理检查,取血测定血糖(GLU),血尿酸(UA)及C反应蛋白(CRP)含量。结果:与正常组比较,模型组GLU,UA及CRP明显升高(P 0. 01);与模型组比较,萆苓组、吡格列酮组血糖下降(P 0. 05);各药物组UA及CRP明显下降(P 0. 01)。与正常组比较,模型组骨骼肌SIRT3蛋白表达量显著降低(P 0. 01);与模型组比较,萆苓组骨骼肌SIRT3蛋白表达量显著提高(P 0. 01),与西药组比较无明显差异;条带图的结果同样显示,与正常组比较,模型组表达亮度明显减弱,药物组表达亮度明显增强;与正常组比较,模型组关节组织URAT1 mRNA相对表达量明显升高(P 0. 01);与模型组比较,各药物组URAT1 mRNA相对表达量显著下调(P 0. 01)。电泳图同样提示,正常组表达亮度减弱,模型组表达亮度显著增强,萆苓组、西药组表达亮度明显减弱。关节病理提示,与正常组比较,模型组大鼠关节病理损伤严重,可见大量炎细胞浸润及纤维增生,滑膜细胞变性、坏死。与模型组比较,萆苓祛痛方关节病变程度明显减低,见少量炎细胞浸润,滑膜上皮轻度增生。结论:具有泻浊解毒通络作用的萆苓祛痛方可显著提高糖尿病痛风大鼠骨骼肌组织SIRT3的蛋白表达量,下调URAT1 mRNA的表达量,减轻骨骼肌组织病理损伤,减低血清炎症因子CRP的含量,降低模型大鼠的血糖、血尿酸水平,有保护关节功能的作用。     

单羧酸转运蛋白1促进胰腺导管癌细胞浸润转移的机制研究

背景与目的：单羧酸转运蛋白1（monocarboxylate transporter 1，MCT1）是细胞转运乳酸、丙酮酸等代谢产物及能量物质的一种重要蛋白质，其在胰腺导管癌中的作用及机制鲜有研究报道。该研究旨在探讨MCT1在胰腺导管癌中的表达及临床病理学意义。方法：纳入78例胰腺导管癌患者的癌组织及癌旁正常组织，运用免疫组织化学技术检测MCT1在癌组织和癌旁正常组织中的表达水平并分析其临床病理学意义。在体外细胞系水平上，我们运用胰腺癌细胞系PANC-1和Capan-1，运用细胞克隆形成实验、细胞划痕和Transwell实验分析沉默MCT1后胰腺癌细胞增殖、迁移和浸润的改变。为明确MCT1的相关作用机制，我们通过生物信息学分析，预测miR-124-3p是MCT1的潜在调控微小RNA；为了进一步验证，我们运用双荧光素酶报告实验分析miR-124-3p对MCT1的调控效果；运用实时荧光定量聚合酶链反应（real-time fluorescence quantitative polymerase chain reaction，RTFQ-PCR）分别检测51对新鲜胰腺癌组织中MCT1和miR-124-3p的基因表达并分析两者的相关性。结果：MCT1的阳性表达主要位于细胞膜和细胞质。相比癌旁正常组织，MCT1在胰腺导管癌组织中显著高表达，其表达水平与胰腺导管癌的分化程度、临床分期、淋巴结转移和不良预后具有显著相关性。在体外细胞系水平上，沉默MCT1能够显著抑制胰腺癌细胞系PANC-1和Capan-1的增殖、迁移和浸润；miR-124-3p在胰腺癌组织中显著低表达，并且与MCT1 mRNA的表达具有显著负相关性，能够负调控MCT1的蛋白表达。结论：MCT1是胰腺导管腺癌的致癌基因，miR-124-3p能够负调控MCT1的表达。     

艳山姜挥发油通过调控巨噬细胞CD36和ABCA1表达抑制泡沫细胞的形成

目的:观察艳山姜挥发油对氧化低密度脂蛋白(ox-LDL)诱导巨噬细胞转化为泡沫细胞的抑制作用,并探索其机制。方法:使用佛波酯(PMA,100μg·L^-1)诱导人白血病单核细胞(THP-1)24 h后形成巨噬细胞,实验分为4组,分别为空白组(无血清RPMI 1640),模型组(80 mg·L^-1ox-LDL),艳山姜挥发油低剂量组(80 mg·L^-1ox-LDL+4μg·L^-1艳山姜挥发油),艳山姜挥发油高剂量组(80 g·L^-1ox-LDL+20μg·L^-1艳山姜挥发油)。噻唑蓝(MTT)比色法检测艳山姜挥发油对巨噬细胞的活性的影响,蛋白免疫印迹法(Western blot)检测巨噬细胞中白细胞分化抗原36(CD36)和三磷酸腺苷结合盒转运体A1(ABCA1)的表达,酶联免疫吸附测定(ELISA)检测巨噬细胞内胆固醇酯含量,油红O染色法检测巨噬细胞中脂质小滴的含量。结果:艳山姜挥发油对巨噬细胞无毒性。与空白组比较,模型组的巨噬细胞内脂滴和胆固醇酯的含量显著增加(P<0.01),CD36蛋白表达显著上升(P<0.01),ABCA1蛋白表达无显著变化;与模型组比较,艳山姜挥发油显著抑制巨噬细胞中脂滴和胆固醇酯的含量(P<0.01),下调CD36的蛋白表达(P<0.01),上调ABCA1蛋白的表达(P<0.01),艳山姜挥发油可抑制巨噬细胞向泡沫细胞的转化。结论:艳山姜挥发油对ox-LDL诱导的巨噬细胞向泡沫细胞的形成具有抑制作用,该药理作用与艳山姜挥发油下调巨噬细胞CD36和上调ABCA1蛋白的表达有关。     

Maternal GABAergic and GnRH/corazonin pathway modulates egg diapause phenotype of the silkworm Bombyx mori

Diapause represents a major developmental switch in insects and is a seasonal adaptation that evolved as a specific subtype of dormancy in most insect species to ensure survival under unfavorable environmental conditions and synchronize populations. However, the hierarchical relationship of the molecular mechanisms involved in the perception of environmental signals to integration in morphological, physiological, behavioral, and reproductive responses remains unclear. In the bivoltine strain of the silkworm Bombyx mori, embryonic diapause is induced transgenerationally as a maternal effect. Progeny diapause is determined by the environmental temperature during embryonic development of the mother. Here, we show that the hierarchical pathway consists of a γ-aminobutyric acid (GABA)ergic and corazonin signaling system modulating progeny diapause induction via diapause hormone release, which may be finely tuned by the temperature-dependent expression of plasma membrane GABA transporter. Furthermore, this signaling pathway possesses similar features to the gonadotropin-releasing hormone (GnRH) signaling system for seasonal reproductive plasticity in vertebrates.

To ensure survival under unfavorable environmental conditions and synchronize populations, most insect species enter diapause, which is a seasonal adaptation that evolved as a specific subtype of dormancy (1, 2). Diapause is not a passive response to changing conditions but rather an actively induced state that precedes adverse natural situations. Therefore, this diapause phenotype is accompanied by changes in energy metabolism or storage to improve cold/stress tolerance in later life stages, or progeny via reproductive switch (3). Although it has been generally suggested that brain/neuroendocrine systems are associated with this seasonal reproductive plasticity in both vertebrates and invertebrates (3, 4), the hierarchical relationship of the molecular mechanisms involved in the perception of environmental signals to integration into morphological, physiological, behavioral, and reproductive responses, known as the diapause syndrome, remains unclear (3).The silkworm Bombyx mori is a typical insect that arrests normal development during early embryogenesis, which is accompanied by metabolic changes in diapause (5, 6). The development of diapause-destined embryos is arrested during the G2 cell cycle stage immediately after the formation of the cephalic lobe and telson and sequential segmentation of the mesoderm (7). The bivoltine strain of B. mori has two generations per year, and progeny diapause is transgenerationally induced as a maternal effect and is determined by the environmental temperature, photoperiod, and nutrient conditions during embryonic and larval development of the mother (5, 6). The temperature signal during the mother’s embryonic development predominantly affects diapause determination, even if silkworms of the bivoltine Kosetsu strain are exposed to all cases of photoperiods during embryonic and larval development. In the Kosetsu strain, when eggs are incubated at 25 °C under continuous darkness, the resultant female moths (25DD) lay diapause eggs in almost all cases. In contrast, incubation of eggs at 15 °C in dark condition results in moths (15DD) that lay nondiapause eggs in almost all cases (6).Embryonic diapause is induced by the diapause hormone (DH) signaling pathway, which consists of highly sensitive and specific interactions between a neuropeptide, DH, and DH receptor (DHR) (6, 8). DH is exclusively synthesized in seven pairs of neurosecretory cells (DH-PBAN–producing neurosecretory cells [DHPCs]) located within the subesophageal ganglion (SG) in the mother’s generation (6). DH is released into the hemolymph during pupal–adult development and acts on the DHR, which belongs to the G protein-coupled receptors (GPCRs) (9). DH levels in the hemolymph are higher in the 25DD than 15DD pupae in the middle of pupal–adult development when the developing ovaries are sensitive to DH (6). Furthermore, the embryonic Bombyx TRPA1 ortholog (BmTRPA1) acts as a thermosensitive channel that is activated at temperatures above ∼21 °C and affects diapause induction through DH release (10). However, there remain questions about the thermal information that is received by BmTRPA1 and linked to DH signaling to induce diapause.From the 1950s, it has been suggested that the DH release was controlled by signals derived from certain region(s) in the brain based on surgical experiments, such as midsagittal bisection or transection (11–13). Especially, the operation in nondiapause producers changed them to diapause producers while transection of the protocerebrum had no effect on the diapause producers. These surgical results suggested the involvement of the protocerebrum in the inhibitory control of DH secretion (12, 14). Furthermore, the accumulation of the ovarian 3-hydroxykynurenine (3-OHK) pigment that accompanies the diapause syndrome was affected by injection with γ-aminobutyric acid (GABA) and the plant alkaloid picrotoxin (PTX), which is a widely used ionotropic GABA and glycine receptor antagonist (15, 16), and the selective ionotropic GABA receptor (GABAR) antagonist bicuculline. This suggests that a GABAergic neurotransmission via ionotropic GABAR is involved in DH secretion, which may be active in nondiapause producers but inactive in diapause producers throughout the pupal–adult development (14, 17). In general, ionotropic GABAR is composed of homo- or hetero-pentameric subunits. All known GABAR subunits display a similar structural scheme, with a large N-terminal extracellular domain involved in the formation of a ligand-binding pocket and a pore domain made of four transmembrane alpha-helices (TM1–TM4) (16, 18). Four homologous sequences of the ionotropic GABAR subunit genes were identified as RDL, LCCH3, GRD, and a GRD-like sequence named 8916 in various insects (19). However, the in vivo physiological roles of both signals derived from the brain and the GABAergic pathway in diapause induction have not been previously investigated.Corazonin (Crz) is an undecapeptide neurohormone sharing a highly conserved amino acid (a.a.) sequence across insect lineages and is involved in different physiological functions, such as heart contraction (20), stress response (21, 22), various metabolic activities (23–25), female fecundity (26), melanization of locust cuticles (27), regulation of ecdysis (28, 29), and control of caste identity (30). Moreover, Crz belongs to the gonadotropin-releasing hormone (GnRH) superfamily alongside adipokinetic hormone (AKH) and AKH/Crz-related peptide (ACP). Duplicates of an ancestral GnRH/Crz signaling system occurred in a common ancestor of protostomes and deuterostomes through coevolution of the ligand receptor (31, 32).Herein, we demonstrated that the hierarchical pathway consists of a GABAergic and Crz signaling system modulating progeny diapause induction by acting on DH release. We propose that the PTX-sensitive GABAergic signal may act to chronically suppress Crz release in dorsolateral Crz neurons (under nondiapause conditions) and that diapause conditions (or PTX injection) inhibits GABAergic signaling, resulting in accelerated Crz release, which in turn induces DH release. GABA signaling may be finely tuned by the temperature-dependent expression of the plasma membrane GABA transporter (GAT), which differs between the 25DD and 15DD conditions. Furthermore, this signaling pathway possesses similar features to the GnRH signaling system with respect to seasonal reproductive plasticity in vertebrates.     

镇心省睡益智方及其精油对AD模型小鼠学习记忆的影响

目的:观察镇心省睡益智方水提液及其精油对β淀粉样前体蛋白基因/早老素基因(APP/PS1)双转基因小鼠学习记忆的影响并探讨其可能机制。方法:采用APP/PS1双转基因痴呆小鼠及同月龄相同遗传背景C57BL/6JNju小鼠2种小鼠。C57BL/6JNju小鼠作为正常组,APP/PS1双转基因痴呆小鼠随机分为模型组,镇心省睡益智方精油低、高质量浓度组(12.13,48.50 mg·L~(-1)),镇心省睡益智方水提液组(0.46 g·kg~(-1)),每组12只。每天给药1次,连续给药22 d。给药结束后采用跳台实验、Morris水迷宫实验对小鼠行为学能力进行检测,采用尼氏染色观察海马CA1区神经元变化,采用硫磺素(Th S)染色观察海马DG区老年斑(SP)沉积,采用免疫组化法检测小鼠脑组织中葡萄糖转运蛋白1(GLUT1),胰岛素受体底物-1(IRS-1)的表达,采用酶联免疫吸附测定(ELISA)检测小鼠海马组织中乙酰胆碱(ACH),γ-氨基丁酸(GABA),谷氨酸(GLU)含量的变化。结果:与正常组比较,模型组小鼠跳台实验潜伏期显著缩短,错误次数显著增加(P0.01),Morris水迷宫实验定位航行逃避潜伏期明显延长(P0.05,P0.01),海马CA1区神经元出现缺失,DG区出现明显的老年斑沉积(P0.05),ACH,GLUT1含量均显著下降(P0.01),GABA,GLU水平及IRS-1的表达均显著升高(P0.01);与模型组比较,各给药组均可显著延长小鼠跳台实验潜伏期、减少跳台错误次数(P0.01),明显降低定位航行小鼠逃避潜伏期(P0.05,P0.01),可一定程度保护小鼠海马CA1区神经元,减少DG区老年斑沉积(P0.05,P0.01),明显增加小鼠脑组织中ACH,GLUT1表达(P0.05,P0.01),显著降低GABA,GLU水平及IRS-1的表达(P0.01)。结论:镇心省睡益智方水提液及其精油能够改善APP/PS1小鼠的学习记忆行为,保护神经元,增加脑组织GLUT1的表达,减少脑组织IRS-1的表达,减少老年斑沉积,升高ACH含量,降低GABA,GLU含量,可能是其防治阿尔茨海默症的机制。     

Drosophila ammonium transporter Rh50 is required for integrity of larval muscles and neuromuscular system

Rhesus glycoproteins (Rh50) have been shown to be ammonia transporters in many species from bacteria to human. They are involved in various physiological processes including acid excretion and pH regulation. Rh50 proteins can also provide a structural link between the cytoskeleton and the plasma membranes that maintain cellular integrity. Although ammonia plays essential roles in the nervous system, in particular at glutamatergic synapses, a potential role for Rh50 proteins at synapses has not yet been investigated. To better understand the function of these proteins in vivo, we studied the unique Rh50 gene of Drosophila melanogaster, which encodes two isoforms, Rh50A and Rh50BC. We found that Drosophila Rh50A is expressed in larval muscles and enriched in the postsynaptic regions of the glutamatergic neuromuscular junctions. Rh50 inactivation by RNA interference selectively in muscle cells caused muscular atrophy in larval stages and pupal lethality. Interestingly, Rh50-deficiency in muscles specifically increased glutamate receptor subunit IIA (GluRIIA) level and the frequency of spontaneous excitatory postsynaptic potentials. Our work therefore highlights a new role for Rh50 proteins in the maintenance of Drosophila muscle architecture and synaptic physiology, which could be conserved in other species.     

Vesicular nucleotide transporter-immunoreactive type I cells associated with P2X3-immunoreactive nerve endings in the rat carotid body

ATP is the major excitatory transmitter from chemoreceptor type I cells to sensory nerve endings in the carotid body, and has been suggested to be released by exocytosis from these cells. We investigated the mRNA expression and immunohistochemical localization of vesicular nucleotide transporter (VNUT) in the rat carotid body. RT-PCR detected mRNA expression of VNUT in extracts of the tissue. Immunoreactivity for VNUT was localized in a part of type I cells immunoreactive for synaptophysin (SYN), but not in glial-like type II cells immunoreactive for S100 and S100B. Among SYN-immunoreactive type I cells, VNUT immunoreactivity was selectively localized in the sub-population of tyrosine hydroxylase (TH)-immunorective type I cells associated with nerve endings immunoreactive for the P2X3 purinoceptor; however, it was not detected in the sub-population of type I cells immunoreactive for dopamine beta-hydroxylase. Multi-immunolabeling for VNUT, P2X3, and Bassoon revealed that Bassoon-immunoreactive products were localized in type I cells with VNUT immunoreactivity, and accumulated on the contact side of P2X3-immunoreactive nerve endings. These results revealed the selective localization of VNUT in the subpopulation of TH-immunoreactive type I cells attached to sensory nerve endings and suggested that these cells release ATP by exocytosis for chemosensory transmission in the carotid body.