Simultaneous determination of LY3214996,abemaciclib,and M2 and M20 metabolites in human plasma,cerebrospinal fluid,and brain tumor by LC-MS/MS

A sensitive and rapid liquid chromatography tandem mass spectrometry(LC-MS/MS)method was established for the quantification of total and unbound concentrations of LY3214996,an extracellular signal-regulated kinase inhibitor;abemaciclib,a cyclin-dependent kinase 4/6 inhibitor;and abemaciclib active metabolites,M2 and M20,in human plasma,brain tumor,and cerebrospinal fluid samples.The method was validated over a concentration range of 0.2e500 nM within a total run time of 3.8 min using isocratic elution on a Kinetex^(TM) F_(5) column.Detection was performed on a Sciex QTRAP 6500t mass spectrometer employing multiple reaction monitoring mode under positive electrospray ionization.The intra-and inter-batch accuracy as well as the precision of the method for all matrices was within ±20% and ≤20% at the lower limit of quantification,and within ±15% and ≤15% for other quality control levels for all analytes.The unbound fractions of drugs and metabolites in spiked and patient samples were determined using an optimized equilibrium dialysis.The validated method was successfully applied in a phase 0/2 clinical trial to assess the central nervous system penetration of LY3214996 and abemaciclib.

Lack of Efficacy of Bevacizumab Plus Irinotecan in Children with Recurrent Malignant Glioma and Diffuse Brainstem Glioma:A Pediatric Brain Tumor Consortium Study

PURPOSE:A phase Ⅱ study of bevacizumab(BVZ) plus irinotecan(CPT-11) was conducted in children with recurrent malignant glioma(MG) and intrinsic brainstem glioma(BSG).PATIENTS AND METHODS:Eligible patients received two doses of BVZ

Histone modification as a drug resistance driver in brain tumors

Patients with brain tumors,specifically,malignant forms such as glioblastoma,medulloblastoma and ependymoma,exhibit dismal survival rates despite advances in treatment strategies.Chemotherapeutics,the primary adjuvant treatment for human brain tumors following surgery,commonly lack efficacy due to either intrinsic or acquired drug resistance.New treatments targeting epigenetic factors are being explored.Post-translational histone modification provides a critical regulatory platform for processes such as chromosome condensation and segregation,apoptosis,gene transcription,and DNA replication and repair.This work reviews how aberrant histone modifications and alterations in histone-modifying enzymes can drive the acquisition of drug resistance in brain tumors.Elucidating these mechanisms should lead to new treatments for overcoming drug resistance.

Brain stem cells as the cell of origin in glioma

Glioma incidence rates in the United States are near 20000 new cases per year, with a median survival time of 14.6 mo for high-grade gliomas due to limited therapeutic options. The origins of these tumors and their many subtypes remain a matter of investigation. Evidence from mouse models of glioma and human clinical data have provided clues about the cell types and initiating oncogenic mutations that drive gliomagenesis, a topic we review here. There has been mixed evidence as to whether or not the cells of origin are neural stem cells, progenitor cells or differentiated progeny. Many of the existing murine models target cell populations defined by lineage-specific promoters or employ lineagetracing methods to track the potential cells of origin. Our ability to target specific cell populations will likely increase concurrently with the knowledge gleaned from an understanding of neurogenesis in the adult brain. The cell of origin is one variable in tumorigenesis, as oncogenes or tumor suppressor genes may differentially transform the neuroglial cell types. Knowledge of key driver mutations and susceptible cell types will allow us to understand cancer biology from a developmental standpoint and enable early interventional strategies and biomarker discovery.

Nonmetabolic functions of pyruvate kinase isoform M2 in controlling cell cycle progression and tumorigenesis

Pyruvate kinase catalyzes the rate-limiting final step of glycolysis, generating adenosine triphosphate (ATP) and pyruvate. The M2 tumor-specific isoform of pyruvate kinase (PKM2) promotes glucose uptake and lactate production in the presence of oxygen, known as aerobic glycolysis or the Warburg effect. As recently reported in Nature, PKM2, besides its metabolic function, has a nonmetabolic function in the direct control of cell cycle progression by activating β-catenin and inducing expression of the β-catenin downstream gene CCND1 (encoding for cyclin D1). This nonmetabolic function of PKM2 is essential for epidermal growth factor receptor (EGFR) activation-induced tumorigenesis.

Regulation of tumor cell migration by protein tyrosine phosphatase (PTP)-proline-, glutamate-, serine-,and threonine-rich sequence(PEST)

Protein tyrosine phosphatase (PTP)-proline-,glutamate-,serine-,and threonine-rich sequence (PEST) is ubiquitously expressed and is a critical regulator of cell adhesion and migration.PTP-PEST activity can be regulated transcriptionally via gene deletion or mutation in several types of human cancers or via post-translational modifications,including phosphorylation,oxidation,and caspase-dependent cleavage.PTP-PEST interacts with and dephosphorylates cytoskeletal and focal adhesion-associated proteins.Dephos-phorylation of PTP-PEST substrates regulates their enzymatic activities and/or their interaction with other proteins and plays an essential role in the tumor cell migration process.

Heme oxygenase-1 system and gastrointestinal tumors

Heme oxygenase-1(HO-1) system catabolizes heme into three products:carbon monoxide,biliverdin/bilirubin and free iron.It is involved in many physiological and pathophysiological processes.A great deal of data has demonstrated the roles of HO-1 in the formation,growth and metastasis of tumors.The interest in this system by investigators involved in gastrointestinal tumors is fairly recent,and few papers on HO-1 have touched upon this subject.This review focuses on the current understanding of the physiological significance of HO-1 induction and its possible roles in the gastrointestinal tumors studied to date.The implications for possible therapeutic manipulation of HO-1 in gastrointestinal tumors are also discussed.

The Expression of Estrogen Receptor Subtypes in Prolactinomas and Their Relationship to Tumor Biological Behavior

Dopamine agonists （DA） are a first-line therapy for prolactinomas （PA）. However, nearly 10% of prolactinomas do not respond to DA therapy. A considerable number of studies have shown that estrogen plays an important role in the development of prolactinomas. However, the expression of estrogen receptors （ER） in prolactinomas has not been fully explored. Accordingly, we examined the levels of ESR1 and its subtypes A5-DeI-ESR1 and ESR2 mRNA in prolactinomas. In the present study,

Suppressing tumor growth of nasopharyngeal carcinoma by hTERTC27 polypeptide delivered through adeno-associated virus plus adenovirus vector cocktail

Nasopharyngeal carcinoma(NPC) is a metastatic carcinoma that is highly prevalent in Southeast Asia. Our laboratory has previously demonstrated that the C-terminal 27-kDa polypeptide of human telomerase reverse transcriptase (hTERTC27) inhibits the growth and tumorigenicity of human glioblastoma and melanoma cells. In this study, we investigated the antitumor effect of hTERTC27 in human C666-1 NPC cells xenografted in a nude mouse model. A cocktail of vectors comprising recombinant adeno-associated virus (rAAV) and recombinant adenovirus (rAdv) that each carry hTERTC27 (rAAV-hTERTC27 and rAdv- hTERTC27; the cocktail was abbreviated to rAAV/rAdv-hTERTC27) was more effective than either rAAV- hTERTC27 or rAdv-hTERTC27 alone in inhibiting the growth of C666-1 NPC xenografts. Furthermore, we established three tumors on each mouse and injected rAAV/rAdv-hTERTC27 into one tumor per mouse. Although hTERTC27 expression could only be detected in the injected tumors, reduced tumor growth was observed in the injected tumor as well as the uninjected tumors, demonstrating that the vector cocktail could provoke an antitumor effect on distant, metastasized tumors. Further studies showed the observed antitumor effects included inducing necrosis and apoptosis and reducing microvessel density. Together, our data suggest that the rAAV/rAdv-hTERTC27 cocktail can potently inhibit NPC tumor growth in both local and metastasized tumors and should be further developed as a novel gene therapy strategy for NPC.

Exploring Chemovar-Specific Cannabis Extracts Quantification and Evaluation of Cytotoxic Compounds for Targeting Glioblastoma Multiforme

Glioblastoma Multiforme (GBM) represents one of the most aggressive and metastatic brain tumors, with a dismal success rate of less than three percent after five years, particularly in tumors with active immune checkpoints. This necessitates the development of targeted endogenous agents for precise GBM treatment. Previous experiments utilizing Chemovar Specific Cannabis Extractions (CSCEs), fractionated with polar solvents and quantified using Liquid and Gas Column Chromatography combined with Mass Spectrometry (LC/GCMS), have shown reduced viability and motility in human GBM cell lines. However, the complexity of the botanical substance has hindered the personalization of standard cannabis medicines for GBM due to unknown synergistic effects of multiple compounds. To address this limitation, our study focuses on exposing AM251 cells to chemovar fractions extracted using a non-polar solvent, thereby isolating a broader spectrum of constituents. By employing LC/GCMS in conjunction with Nuclear Magnetic Resonance (NMR), we have identified and quantified nine* compounds present in the non-polar CSCE that exhibit significant efficacy (0.1 μM) in inducing cytotoxicity* in GBM tumor cells. Conversely, the polar fraction in our experiment did not demonstrate efficacy against UM251 cells. The quantification of individual compounds within a cannabis extraction that selectively induces cell death in brain tumors holds promise for guiding future research and facilitating the development of a standardized CSCE for GBM therapy.

eIF4A1与TrkA相互作用后抑制TrkA的泛素化（英文）

神经生长因子(NGF)结合细胞表面受体p75NTR (p75神经营养素受体)和TrkA (酪氨酸蛋白激酶A)后介导了细胞分化、细胞生存、凋亡、增殖和侵袭等多个重要的生理病理过程. TrKA能与细胞内多个蛋白质相互作用,但是由于NGF信号通路的复杂性,现在仍有必要发现与之相互作用的蛋白质以更准确地了解NGF信号通路.本研究中我们通过酵母双杂交的方法筛选到了一个新的与TrKA相互作用的蛋白质——真核生物翻译起始因子4A1 (eIF4A1),然后通过谷胱甘肽巯基转移酶融合蛋白沉降实验(GST-pull-down)和免疫共沉淀实验(Co-IP)证明了TrkA和eIF4A1的相互作用.此外NGF能够增强TrkA和eIF4A1的相互作用.在鉴定相互作用位点实验中,我们发现eIF4A1的氨基端结构域和TrkA的TK结构域参与了相互作用. TrkA和e IF4A1共定位在细胞膜上. NGF能够引起TrkA与泛素蛋白63位的赖氨酸连接,而eIF4A1与TrkA相互作用后能够抑制TrkA与泛素蛋白63位的赖氨酸连接.综上,得出结论 e IF4A1通过与TrkA相互作用抑制其泛素化调控NGF信号通路.

New insights into estrogenic regulation of O^6-methylguanine DNA-methyltransferase (MGMT) in human breast cancer cells： Co-degradation of ER-α and MGMT proteins by fulvestrant or O^6-benzylguanine indicates fresh avenues for therapy

Endocrine therapy using estrogen receptor-u （ER-α） antagonists for attenuating horm2one-driven cell proliferation is a major treatment modality for breast cancers. To exploit any DNA repair deficiencies associated with endocrine therapy, we investigated the functional and physical interactions of ER-α with O^6-methylguanine DNA methyltransferase （MGMT）, a unique DNA repair protein that confers tumor resistance to various anticancer alkylating agents. The ER-α -positive breast cancer cell lines （MCF-7, T47D） and ER- negative cell lines （MDAMB- 468, MDAMB-231）, and established inhibitors of ER-α and MGMT, namely, ICI-182,780 （Faslodex） and O^6- benzylguanine, respectively, were used to study MGMT- ER interactions. The MGMT gene promoter was found to harbor one full and two half estrogen-responsive elements （EREs） and two antioxidant-responsive elements （AREs）. MGMT expression was upregulated by estrogen, downregulated by tamoxifen in Western blot and promoter-linked reporter assays. Similarly, both transient and stable transfections of Nrf-2 （nuclear factor-erythroid 2-related factor-2） increased the levels of MGMT protein and activity 3 to 4-fold reflecting novel regulatory nodes for this dragresistance determinant. Of the different ER-α antagonists tested, the pure anti-estrogen fulvestrant was most potent in inhibiting the MGMT activity in a dose, time and ER-α dependent manner, similar to O^6-benzylguanine. Interestingly, fulvestrant exposure led to a degradation of both ER-α and MGMT proteins and O^6-benzylguanine also induced a specific loss of ER-a and MGMT proteins in MCF-7 and T47D breast cancer cells with similar kinetics. Immunoprecipitation revealed a specific association of ER-a and MGMT proteins in breast cancer cells. Furthermore, silencing of MGMT gene expression triggered a decrease in the levels of both MGMT and ER-a proteins. The involvement of proteasome in the drug-induced degradation of both proteins was also demonstrated. Fulvestrant enhanced the cytotoxicity of MGMT-targeted alkylating agents, namely, temozolomide and BCNU by 3 to 4-fold in ER-α positive cells, but not in ER-negative cells. We conclude that MGMT and ER-α proteins exist as a complex and are co-targeted for ubiquitin-conjugation and subsequent proteasomal degradation. The findings offer a clear rationale for combining alkylating agents with endocrine therapy.

Glioblastoma stem cells:Molecular characteristics and therapeutic implications

Glioblastoma Multiforme(GBM)is a grade IV astrocytoma,with a median survival of 14.6 mo.Within GBM,stem-like cells,namely glioblastoma stem cells(GSCs),have the ability to self-renew,differentiate into distinct lineages within the tumor and initiate tumor xenografts in immunocompromised animal models.More importantly,GSCs utilize cell-autonomous and tumor microenvironment-mediated mechanisms to overcome current therapeutic approaches.They are,therefore,very important therapeutic targets.Although the functional criteria defining GSCs are well defined,their molecular characteristics,the mechanisms whereby they establish the cellular hierarchy within tumors,and their contribution to tumor heterogeneity are not well understood.This review is aimed at summarizing current findings about GSCs and their therapeutic importance from a molecular and cellular point of view.A better characterization of GSCs is crucial for designing effective GSCtargeted therapies.

Mouse models of medulloblastoma

Medulloblastoma is the most common malignant pediatric brain tumor. Despite its prevalence and importance in pediatric neuro-oncology, the genes and pathways responsible for its initiation, maintenance, and progression remain poorly understood. Genetically engineered mouse models are an essential tool for uncovering the molecular and cellular basis of human diseases, including cancer, and serve a valuable role as preclinical models for testing targeted therapies. In this review, we summarize how such models have been successfully applied to the study of medulloblastoma over the past decade and what we might expect in the coming years.

Anti-porcine circovirus type 2(PCV2) antibody placental barrier leakage from sow to fetus: impact on the diagnosis of intra-uterine PCV2 infection

Dear Editor,Fetuses develop antibodies when they are infectedwith porcine circovirus type 2(PCV2).At abortion orbirth,both PCV2 and/or anti-PCV2 antibodies can thenbe detected.Finding anti-PCV2 antibodies in aborted fe-tuses or stillborn piglets is generally used as evidence ofan intra-uterine PCV2 infection.However,a recent anal-ysis of fetuses sent in for PCV2 diagnosis and caesare-an-derived,colostrum-deprived pigs revealed that

Glioma extent of resection and its impact on patient outcome

Neurosurgery. 2008 Apr;62(4):753-64; discussion 264-246.OBJECTIVE: There is still no general consensus in the literature regarding the role of extent of glioma resection in im-proving patient outcome. Although the importance of resection in obtaining tissue diagnosis and alleviating symptoms is clear,

EA-IL-15溶瘤腺病毒的构建及其对胶质瘤细胞特异性及有效性研究

目的构建插入EA-IL-15双基因的溶瘤腺病毒(oAD-EA-IL-15),探讨其在体外对胶质瘤细胞的杀伤效果和特异性。方法PCR法将EA-IL-15双基因插入腺病毒穿梭载体pXC1,将穿梭质粒pXC1-EA-IL-15及辅助质粒pBHG loxΔE1,3 Cre质粒共转染HEK393细胞,获得溶瘤腺病毒oAD-EA-IL-15。通过CCK-8细胞毒性实验,测定细胞相对活性,绘制剂量反应曲线。结果成功构建溶瘤腺病毒载体(oAD)及含EA-IL-15双基因的溶瘤腺病毒载体(oAD-EA-IL-15);体外包装获得相应的溶瘤腺病毒oAD和oAD-EA-IL-15;oAD对小鼠胶质瘤细胞GL261有明显杀伤作用(P<0.05),对小胶质细胞BV2(非肿瘤细胞)的杀伤作用明显低于对GL261(P<0.05),说明oAD具有特异性;oAD-EA-IL-15和oAD分别感染GL261、BV2细胞,对于GL261,oAD-EA-IL-15的半抑制浓度(IC 50)值为0.58×107±1.30×105 PFU/ml较oAD的IC 50值1.13×107±1.98×105PFU/ml低,对肿瘤细胞的杀伤作用强于oAD(P<0.01),对于BV2,oAD-EA-IL-15对其活性的影响低于oAD(P<0.01),说明oAD-EA-IL-15病毒的特异性优于oAD病毒。结论携带EA-IL-15双基因的溶瘤腺病毒在体外对胶质瘤细胞具有明显的杀伤作用和特异性,可为胶质瘤治疗提供更加特异有效的途径。