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Venetoclax (VEN), in combination with low dose cytarabine (AraC) or a hypomethylating agent, is FDA approved to treat acute myeloid leukemia (AML) in patients who are over the age of 75 or cannot tolerate standard chemotherapy. Despite high response rates to these combination therapies, most patients succumb to the disease due to relapse and/or drug resistance, providing an unmet clinical need for novel therapies to improve AML patient survival. ME-344 is a potent isoflavone with demonstrated inhibitory activity toward oxidative phosphorylation (OXPHOS) and clinical activity in solid tumors. Given that OXPHOS inhibition enhances VEN antileukemic activity against AML, we hypothesized that ME-344 could enhance the anti-AML activity of VEN. Here we report that ME-344 synergized with VEN to target AML cell lines and primary patient samples while sparing normal hematopoietic cells. Cooperative suppression of OXPHOS was detected in a subset of AML cell lines and primary patient samples. Metabolomics analysis revealed a significant reduction of purine biosynthesis metabolites by ME-344. Further, lometrexol, an inhibitor of purine biosynthesis, synergistically enhanced VEN-induced apoptosis in AML cell lines. Interestingly, AML cells with acquired resistance to AraC showed significantly increased purine biosynthesis metabolites and sensitivities to ME-344. Furthermore, synergy between ME-344 and VEN was preserved in these AraC-resistant AML cells. These results translated into significantly prolonged survival upon combination of ME-344 and VEN in NSGS mice bearing parental or AraC-resistant MV4-11 leukemia. This study demonstrates that ME-344 enhances VEN antileukemic activity against preclinical models of AML by suppressing OXPHOS and/or purine biosynthesis.

Supplementary Method Descriptions Molecular modeling and computational studies Enzyme expression and purification. In vitro enzymatic assays and Ki determinations In vivo efficacy trials with MIA PaCa-2 pancreatic cancer xenografts. Cytochrome c oxidase assay Synthesis of AGF94 and 5-substituted pyrrolo[3,2-d]pyrimidine compounds

Folate-dependent one-carbon (C1) metabolism is compartmentalized into the mitochondria and cytosol and supports cell growth through nucleotide and amino acid biosynthesis. Mitochondrial C1 metabolism, including serine hydroxymethyltransferase (SHMT) 2, provides glycine, NAD(P)H, ATP, and C1 units for cytosolic biosynthetic reactions, and is implicated in the oncogenic phenotype across a wide range of cancers. Whereas multitargeted inhibitors of cytosolic C1 metabolism, such as pemetrexed, are used clinically, there are currently no anticancer drugs that specifically target mitochondrial C1 metabolism. We used molecular modeling to design novel small-molecule pyrrolo[3,2-d]pyrimidine inhibitors targeting mitochondrial C1 metabolism at SHMT2. In vitro antitumor efficacy was established with the lead compounds (AGF291, AGF320, AGF347) toward lung, colon, and pancreatic cancer cells. Intracellular targets were identified by metabolic rescue with glycine and nucleosides, and by targeted metabolomics using a stable isotope tracer, with confirmation by in vitro assays with purified enzymes. In addition to targeting SHMT2, inhibition of the cytosolic purine biosynthetic enzymes, β-glycinamide ribonucleotide formyltransferase and/or 5-aminoimidazole-4-carboxamide ribonucleotide formyltransferase, and SHMT1 was also established. AGF347 generated significant in vivo antitumor efficacy with potential for complete responses against both early-stage and upstage MIA PaCa-2 pancreatic tumor xenografts, providing compelling proof-of-concept for therapeutic targeting of SHMT2 and cytosolic C1 enzymes by this series. Our results establish structure–activity relationships and identify exciting new drug prototypes for further development as multitargeted antitumor agents.

The triple-negative breast cancer (TNBC) subtype, regardless of their BRCA1 status, has the poorest outcome compared with other breast cancer subtypes, and currently there are no approved targeted therapies for TNBC. We have previously demonstrated the importance of RAD6-mediated translesion synthesis pathway in TNBC development/progression and chemoresistance, and the potential therapeutic benefit of targeting RAD6 with a RAD6-selective small-molecule inhibitor, SMI#9. To overcome SMI#9 solubility limitations, we recently developed a gold nanoparticle (GNP)-based platform for conjugation and intracellular release of SMI#9, and demonstrated its in vitro cytotoxic activity toward TNBC cells. Here, we characterized the in vivo pharmacokinetic and therapeutic properties of PEGylated GNP-conjugated SMI#9 in BRCA1 wild-type and BRCA1-mutant TNBC xenograft models, and investigated the impact of RAD6 inhibition on TNBC metabolism by 1H-NMR spectroscopy. GNP conjugation allowed the released SMI#9 to achieve higher systemic exposure and longer retention as compared with the unconjugated drug. Systemically administered SMI#9-GNP inhibited the TNBC growth as effectively as intratumorally injected unconjugated SMI#9. Inductively coupled mass spectrometry analysis showed highest GNP concentrations in tumors and liver of SMI#9-GNP and blank-GNP–treated mice; however, tumor growth inhibition occurred only in the SMI#9-GNP–treated group. SMI#9-GNP was tolerated without overt signs of toxicity. SMI#9-induced sensitization was associated with perturbation of a common set of glycolytic pathways in BRCA1 wild-type and BRCA1-mutant TNBC cells. These data reveal novel SMI#9 sensitive markers of metabolic vulnerability for TNBC management and suggest that nanotherapy-mediated RAD6 inhibition offers a promising strategy for TNBC treatment.

Contains Materials, Method of metabolite extraction and 1H-NMR analysis. Supplementary Table S1 shows size measurements of GNPs. Supplementary Table S2 shows summary of metabolic pathway analysis in SUM1315 triple negative breast cancer cells. Supplementary Table S3 shows summary of metabolic pathway analysis in MDA-MB-231 triple negative breast cancer cells. Supplementary Figure S1 shows PCA loading plots of SUM1315 and MDA-MB-231 cells treated with blank-GNP or SMI#9-GNP. Supplementary Figure S2 shows PLS-DA plots of SUM1315 and MDA-MB-231 cells treated with blank-GNP or SMI#9-GNP.

Supplementary Figure S1 shows in vitro antiproliferative activity and targeted pathways of previously reported AICARFTase and GARFTase inhibitors. Supplementary Figure S2 shows docking of AGF291, AGF320, and AGF347 (along with 5-formyl-THF) in human SHMT2 and rabbit SHMT1. Supplementary Figure S3 shows plasma membrane folate transporter expression levels in H460, HCT116, and MIA PaCa-2 human tumor cell lines as compared to those in the IGROV-1 epithelial ovarian cancer cell line. Supplementary Figure S4 shows in vitro antiproliferative activity and targeted pathways of AGF291, AGF320, and AGF347 along with previously reported GARFTase inhibitor AGF94 in H460, HCT116, and MIA PaCa-2 cell lines. Supplementary Figure S5 shows targeted metabolomics data on total serine, serine isotope labeling patterns, total GAR, total AICAR, total adenine nucleotides, and total dTTP along with isotope labeling patterns of H460, HCT116, and MIA PaCa-2 cell lines treated with AGF291, AGF320, and AGF347 not shown in main text Figure 4. Supplementary Figure S6 shows a Western blot confirming knockdown of SHMT2 in H460 SHMT2 KD cell line and knockout of SHMT2 in HCT116 SHMT2 KO cell line. Supplementary Figure S7 shows in vivo efficacies of AGF347 and gemcitabine towards MIA PaCa-2 early and late stage tumor xenograft models where mouse serum folate levels were not depleted to approximate those found in humans. Supplementary Figure S8 shows a cytochrome c oxidase assay on tumors harvested from the metabolomics arm of the late stage in vivo AGF347 trial. Table S1 shows docking scores of novel compounds in human SHMT2 and rabbit SHMT1 (corresponding to Supplementary Figure S2). Table S2 shows quantitative data from in vivo early- and late-stage trials of AGF347 and gemcitabine against MIA PaCa-2 tumor xenografts in NCR SCID mice.

Pharmacodynamic analysis of surgical glioblastoma tissue after short-term ribociclib treatment

Purpose:Testosterone suppression in prostate cancer is limited by serious side effects and resistance via restoration of androgen receptor (AR) functionality. ELK1 is required for AR-dependent growth in various hormone-dependent and castration-resistant prostate cancer models. The amino-terminal domain of AR docks at two sites on ELK1 to coactivate essential growth genes. This study explores the ability of small molecules to disrupt the ELK1–AR interaction in the spectrum of prostate cancer, inhibiting AR activity in a manner that would predict functional tumor selectivity.Experimental Design:Small-molecule drug discovery and extensive biological characterization of a lead compound.Results:We have discovered a lead molecule (KCI807) that selectively disrupts ELK1-dependent promoter activation by wild-type and variant ARs without interfering with ELK1 activation by ERK. KCI807 has an obligatory flavone scaffold and functional hydroxyl groups on C5 and C3′. KCI807 binds to AR, blocking ELK1 binding, and selectively blocks recruitment of AR to chromatin by ELK1. KCI807 primarily affects a subset of AR target growth genes selectively suppressing AR-dependent growth of prostate cancer cell lines with a better inhibitory profile than enzalutamide. KCI807 also inhibits in vivo growth of castration/enzalutamide-resistant cell line–derived and patient-derived tumor xenografts. In the rodent model, KCI807 has a plasma half-life of 6 hours, and maintenance of its antitumor effect is limited by self-induced metabolism at its 3′-hydroxyl.Conclusions:The results offer a mechanism-based therapeutic paradigm for disrupting the AR growth-promoting axis in the spectrum of prostate tumors while reducing global suppression of testosterone actions. KCI807 offers a good lead molecule for drug development.

Purpose:CDK4/6-dependent cell-cycle regulation is disrupted in most glioblastomas. This study assesses the central nervous system (CNS) pharmacokinetics and tumor pharmacodynamics of ribociclib, a highly selective CDK4/6 inhibitor, in patients with recurrent glioblastoma.Patients and Methods:Patients with recurrent glioblastoma with intact retinoblastoma protein (RB) expression and CDKN2A deletion or CDK4/6 amplification were treated with ribociclib daily (900 mg) for 5 days before tumor resection. Blood, tumor, and cerebrospinal fluid (CSF) samples were collected, and total and unbound ribociclib concentrations were determined. Pharmacodynamic effects, assessed by RB and FOXM1 phosphorylation, were compared with matched archival tissue. Patients with positive pharmacokinetic and pharmacodynamic effects were enrolled into the expansion cohort for preliminary assessment of progression-free survival (PFS).Results:Twelve patients were enrolled. The mean unbound ribociclib concentrations in CSF, nonenhancing, and enhancing tumor regions were 0.374 μmol/L, 0.560, and 2.152 μmol/kg, respectively, which were more than 5-fold the in vitro IC50 for inhibition of CDK4/6 (0.04 μmol/L). G1-to-S phase suppression was inferred by decreases in phosphorylation of RB (P < 0.01) and cellular proliferation (P < 0.05). Six of 12 patients were enrolled into the pharmacokinetic/pharmacodynamic-guided expansion cohort and demonstrated a median PFS of 9.7 weeks. Examination of recurrent tumors following monotherapy indicated upregulation of the PI3K/mTOR pathway.Conclusions:Ribociclib exhibited good CNS penetration, and target modulation was indicated by inhibition of RB phosphorylation and tumor proliferation. Ribociclib monotherapy showed limited clinical efficacy in patients with recurrent glioblastoma. Combination therapy with CDK4/6 and PI3K/mTOR inhibitors may be explored for treating recurrent glioblastoma.

Supplementary figures #1-#15

Supplementary Tables #1-4

SUPPLEMENTARY METHODS Supplementary Figure 1 Overall metabolic kinetics of AZD1775 in human liver and intestinal microsomes (HLM and HIM). Supplementary Figure 2 PBPK model simulations showing the impact of BBB integrity (i.e., PSB), transporter activity (i.e., CLefflux,vivo and CLuptake,vivo), and drug binding to brain tissues (i.e., fu,br) on the extent of AZD1775 BBB penetration (assessed by Kp,uu) and the rate of penetration (assessed by Tmax,br).

Supplementary Data from Mechanistic Modeling of Central Nervous System Pharmacokinetics and Target Engagement of HER2 Tyrosine Kinase Inhibitors to Inform Treatment of Breast Cancer Brain Metastases

Purpose: AZD1775, a first-in-class, small-molecule inhibitor of the Wee1 tyrosine kinase, is under evaluation as a potential chemo- and radiosensitizer for treating glioblastoma. This study was to prospectively, quantitatively, and mechanistically investigate the penetration of AZD1775 across the human blood–brain barrier (BBB).Experimental Design: AZD1775 plasma and tumor pharmacokinetics were evaluated in 20 patients with glioblastoma. The drug metabolism, transcellular passive permeability, and interactions with efflux and uptake transporters were determined using human derived in vitro systems. A whole-body physiologically based pharmacokinetic (PBPK) model integrated with a four-compartment permeability-limited brain model was developed for predicting the kinetics of AZD1775 BBB penetration and assessing the factors modulating this process.Results: AZD1775 exhibited good tumor penetration in patients with glioblastoma, with the unbound tumor-to-plasma concentration ratio ranging from 1.3 to 24.4 (median, 3.2). It was a substrate for ABCB1, ABCG2, and OATP1A2, but not for OATP2B1 or OAT3. AZD1775 transcellular passive permeability and active efflux clearance across MDCKII–ABCB1 or MDCKII–ABCG2 cell monolayers were dependent on the basolateral pH. The PBPK model well predicted observed drug plasma and tumor concentrations in patients. The extent and rate of drug BBB penetration were influenced by BBB integrity, efflux and uptake active transporter activity, and drug binding to brain tissue.Conclusions: In the relatively acidic tumor microenvironment where ABCB1/ABCG2 transporter-mediated efflux clearance is reduced, OATP1A2-mediated active uptake becomes dominant, driving AZD1775 penetration into brain tumor. Variations in the brain tumor regional pH, transporter expression/activity, and BBB integrity collectively contribute to the heterogeneity of AZD1775 penetration into brain tumors. Clin Cancer Res; 23(24); 7454–66. ©2017 AACR.See related commentary by Peer et al., p. 7437

Purpose:This study evaluated the central nervous system (CNS) pharmacokinetics and target engagement of lapatinib, neratinib, and tucatinib in patients with cancer, using a physiologically based pharmacokinetic (PBPK) modeling approach.Experimental Design:Drug-specific parameters for in vitro metabolism, binding to plasma proteins and brain tissues, transcellular passive permeability, and interactions with efflux transporters were determined. Whole-body PBPK models integrated with a 4-compartment permeability-limited brain model was developed and verified for predicting plasma and CNS pharmacokinetics. Target engagement ratio (TER), defined as the ratio of the average steady-state unbound drug brain concentration (Css,ave,br) to in vitro IC50 for HER2 inhibition, was used as a predictor of intracranial efficacy.Results:PBPK models predicted that following 1 cycle of standard dosing, tucatinib and lapatinib achieved similar Css,ave,br (14.5 vs. 16.8 nmol/L), while neratinib Css,ave,br (0.68 nmol/L) was 20-fold lower. Tucatinib and neratinib were equally potent for HER2 inhibition (IC50, 6.9 vs. 5.6 nmol/L), while lapatinib was less potent (IC50, 109 nmol/L). The model-predicted population mean TER in the human normal brain was 2.1 for tucatinib, but < 0.20 for lapatinib and neratinib.Conclusions:The PBPK modeling suggests that tucatinib induces sufficient HER2 inhibition (TER > 2.0) in not only brain metastases with a disrupted blood–brain barrier (BBB), but also micrometastases where the BBB largely remains intact. These findings, in line with available clinical pharmacokinetics and efficacy data, support the therapeutic value of tucatinib for treatment of brain metastases and warrant further clinical investigation for the prevention of brain metastases in patients with HER2-positive breast cancer.

Purpose: Ceritinib is an orally bioavailable, small-molecule inhibitor of anaplastic lympoma kinase (ALK), insulin-like growth factor 1 receptor (IGFR1), and focal adhesion kinase (FAK), which are highly expressed in glioblastoma and many brain metastases. Preclinical and clinical studies indicate that ceritinib has antitumor activity in central nervous system (CNS) malignancies. This phase 0 trial measured the tumor pharmacokinetics (PK) and pharmacodynamics (PD) of ceritinib in patients with brain metastasis or recurrent glioblastoma. Patients and Methods: Preoperative patients with brain tumors demonstrating high expression of pSTAT5b/pFAK/pIGFR1 were administered ceritinib for 10 days prior to tumor resection. Plasma, tumor, and cerebrospinal fluid (CSF) samples were collected at predefined timepoints following the final dose. Total and unbound drug concentrations were determined using LC-MS/MS. In treated tumor and matched archival tissues, tumor PD was quantified through IHC analysis of pALK, pSTAT5b, pFAK, pIGFR1, and pIRS1. Results: Ten patients (3 brain metastasis, 7 glioblastoma) were enrolled and no dose-limiting toxicities were observed. Ceritinib was highly bound to human plasma protein [median fraction unbound (Fu), 1.4%] and to brain tumor tissue (median Fu, 0.051% and 0.045% in gadolinium-enhancing and -nonenhancing regions respectively). Median unbound concentrations in enhancing and nonenhancing tumor were 0.048 and 0.006 μmol/L, respectively. Median unbound tumor-to-plasma ratios were 2.86 and 0.33 in enhancing and nonenhancing tumor, respectively. No changes in PD biomarkers were observed in the treated tumor samples as compared to matched archival tumor tissue. Conclusions: Ceritinib is highly bound to plasma proteins and tumor tissues. Unbound drug concentrations achieved in brain metastases and patients with recurrent glioblastoma were insufficient for target modulation.

Sensitivity enhancement in proton transfer reaction mass spectrometry (PTR-MS) is an important development direction. We developed a novel drift tube called a focusing quadrupole ion funnel (FQ-IF) for use in PTR-MS to improve the sensitivity. The FQ-IF consists of 20 layers of stainless steel electrodes, and each layer has 4 quarter rings. The first 6 layers have a constant inner hole diameter of 22 mm; the latter 14 layers taper the inner diameter down to 8 mm. The FQ-IF drift tube can also operate in the direct current (DC) mode (similar to a conventional drift tube) and ion funnel (IF) mode (similar to a conventional ion funnel drift tube) by changing the voltage loading method. The simulation results show that the transmission efficiency of the FQ-IF is significantly improved compared to that of the other two modes. Further experiments show that the product ions of limonene tend to convert into smaller

The increase in extreme precipitation in summer is one of the clearest changes in climate observed in Shanxi Province, China. The loess is dry, loose uncemented, and has well-developed internal pores in initial state. When extreme rainfall occurs, the special structure of loess provides a favorable channel for rainwater infiltration, which means decreasing the shear strength parameters. Loess landslide induced by extreme rainfall has caused great economic losses and casualties. This paper takes the Beiyin landslide as an example, the seepage field of the loess slope under rainfall infiltration is analyzed by the finite element method, and the stability of the loess slope is analyzed by the limit equilibrium method based on field survey. The pore water pressure, saturation zone, and horizontal seepage velocity at different altitudes of the loess landslide are investigated under various extreme precipitation. The results showed that the concentrated infiltration of extreme rainfall was in the trailing edge of the landslide, formed a saturated zone in the Tertiary water-resisting clay layer, and extended to the slope angle. When the saturated zone is formed in the middle shallow layer of the landslide and connects with the saturated zone of the trailing edge, the sliding force of each block is greater than the anti-sliding force in the sliding section and the slope will be unstable.

Pamiparib (BGB-290) is an orally bioavailable, small molecule inhibitor of poly (ADP-ribose) polymerase 1 (PARP1) and PARP2. A reversed-phase LC with tandem mass spectrometry method was developed and fully validated for determining total and unbound pamiparib concentrations in human plasma and brain tumor tissue. Plasma and tissue homogenate samples were prepared by methanol protein precipitation. Pamiparib and the internal standard [(13)C(2),(15)N(2)]pamiparib were separated on a Waters BEH C(18) (50 × 2.1 mm, 1.7 μm) column, with a gradient elution consisting of mobile phases A (0.1% formic acid in water) and B (0.1% formic acid in acetonitrile) at a flow rate of 0.25 mL/min. The analytes were monitored with multiple reaction monitoring mode under positive electrospray ionization. The method was fully validated for specificity, linearity, accuracy and precision, matrix effect and recovery, and short- and long-term stability. The lower limit of quantitation was 0.5 nM of pamiparib in plasma or tissue homogenate. The calibration curve was linear over the pamiparib concentration range of 0.5–1000 nM in plasma. The intra- and inter-day precision and accuracy were within the generally accepted criteria for bioanalytical method. Pamiparib was stable in plasma at −80°C for at least 6 months. The method was successfully applied to assess the plasma and tumor pharmacokinetics of total and unbound pamiparib in patients with glioma.

Suicide is commonly found in patients with major depressive disorder (MDD), while the associations among depressive symptoms and their relationships with suicidal risk remain unclear. This study identified the symptoms associated with suicidal risk and the most central symptoms in the MDD networks based on both self-reported and clinical-interview scales. A total of 446 outpatients with MDD were recruited. The Mini International Neuropsychiatric Interview (MINI) was used to assess the suicidal risk. The 13-item Beck Depression Inventory (BDI-13) and 17-item Hamilton Depression Rating Scale (HAMD-17) were used to measure the depressive symptoms. Network analysis was used to estimate the network models. Ten symptoms in the BDI-13 network were related to suicidal risk, among which sadness had the strongest association. Among the six symptoms in the HAMD-17 network that were associated with suicidal risk, guilty feeling was the strongest. Sense of failure was the most central symptom in the BDI-13 network, while depressed mood had the highest centrality in the HAMD-17 network. The depressive symptoms related to suicide risk and the clinical features of MDD showed different characteristics based on different assessment types. Combining self-reported and clinician-rated assessments in future studies and clinical practice might lead to some new findings.

Childhood trauma and empathy deficits have been found to be related to borderline personality disorder (BPD), but the mechanisms of action remain unclear. This study aims to investigate the charact...

This study determined absolute transporter protein abundances in isolated microvessels of human noncancerous cerebral cortex as well as brain metastases of patients with lung and breast cancer, using a validated targeted proteomics approach. As compared with those in microvessels of noncancerous cerebral cortex, the median protein abundances of glucose transporter 1 (a brain endothelial marker) and sodium‐potassium pump (Na/K ATPase, a plasma membrane marker) were decreased by ~ 80% in brain metastasis microvessels. The major efflux transporters (ABCB1 and ABCG2) fell to undetectable in microvessels of more than 80% of brain metastasis specimens. Monocarboxylate transporter 1 was undetectable in microvessels of more than 80% of brain metastases, whereas large neutral amino acid transporter 1 levels remained unchanged. In conclusion, the integrity of the physical and biochemical barrier with respect to transporter protein expression is largely disrupted in brain metastasis tumor vasculatures. Differential transporter protein abundances at the blood‐brain barrier and blood‐brain tumor barrier provided mechanistic and quantitative basis for prediction of heterogeneous drug penetration into human brain and brain tumors, which is critical not only to the understanding of the success or failure of systemic chemotherapy in the treatment of brain tumors but also to the development of more effective therapeutic strategies.

We have developed and characterized a novel drift tube called the direct current-ion funnel (DC-ion funnel) drift tube, consisting of 20 traditional ring electrodes and 5 new DC-focusing electrodes (DC-FEs) for use in proton transfer reaction mass spectrometry (PTR-MS). Ion trajectory simulations demonstrate the ion focusing effect of the DC-FE and DC-ion funnel drift tube. Further comparative experiments show that the PTR-MS with the novel DC-ion funnel drift tube has a higher sensitivity (3.8-7.3 times for the volatile organic compounds considered in this work) than the PTR-MS with a traditional drift tube. Different from conventional radiofrequency (rf) focusing methods, the DC-ion funnel drift tube can realize ion focusing with only a DC electric field and no additional rf power supply, which makes it especially suitable for instruments requiring miniaturization and low power consumption to improve detection sensitivity. In addition, the DC-ion funnel drift tube can easily be coupled to other types of mass spectrometers to increase their detection sensitivity.

Deregulation of metabolism and disruption of genome integrity are hallmarks of cancer1. Increased levels of the metabolites 2-hydroxyglutarate, succinate and fumarate occur in human malignancies owing to somatic mutations in the isocitrate dehydrogenase-1 or -2 (IDH1 or IDH2) genes, or germline mutations in the fumarate hydratase (FH) and succinate dehydrogenase genes (SDHA, SDHB, SDHC and SDHD), respectively2-4. Recent work has made an unexpected connection between these metabolites and DNA repair by showing that they suppress the pathway of homology-dependent repair (HDR)5,6 and confer an exquisite sensitivity to inhibitors of poly (ADP-ribose) polymerase (PARP) that are being tested in clinical trials. However, the mechanism by which these oncometabolites inhibit HDR remains poorly understood. Here we determine the pathway by which these metabolites disrupt DNA repair. We show that oncometabolite-induced inhibition of the lysine demethylase KDM4B results in aberrant hypermethylation of histone 3 lysine 9 (H3K9) at loci surrounding DNA breaks, masking a local H3K9 trimethylation signal that is essential for the proper execution of HDR. Consequently, recruitment of TIP60 and ATM, two key proximal HDR factors, is substantially impaired at DNA breaks, with reduced end resection and diminished recruitment of downstream repair factors. These findings provide a mechanistic basis for oncometabolite-induced HDR suppression and may guide effective strategies to exploit these defects for therapeutic gain.

Sodium-ion batteries (SIBs) are recognized as attractive alternatives for grid-scale electrochemical energy storage applications. Transition metal oxide cathodes represent one of the most dynamic materials for industrialization among the various cathodes for SIBs. Here, a cation-doped cathode Na

Butanol is a common organic solvent used in latex paint, and one of its isomers, tert-butanol, is toxic and can cause potential harm to the human body. Therefore, it is of great significance to develop a qualitative and quantitative detection method for butanol isomers. In this study, we combined the advantages of rapid detection of proton transfer reaction mass spectrometry (PTR-MS) with the separation and qualitative capabilities of gas chromatography-mass spectrometry (GC-MS) to achieve the detection of isomers, building a fast gas chromatography proton transfer reaction mass spectrometry (FastGC-PTR-MS) equipment. Firstly, the developed technology was optimized using standard samples of several common volatile organic compounds. The retention times of acetonitrile, acetone, and alcohols were less than 50 s, and the retention times of the benzene series were less than 110 s, on the premise that these isomers could be basically separated (resolution R 1.0). Compared with a commercial GC-MS equipment, the detection times were shortened by 5-6 times and 2-4 times, respectively. Then the FastGC-PTR-MS was applied to detect the isomers of butanol in latex paint. The results showed that the headspace of brand D latex paint mainly contained five substances: tert-butanol, n-butanol, acetaldehyde, methanol, and acetone. Tert-butanol and n-butanol could be completely separated (R 1.5). The concentration of tert-butanol was 4.41 ppmv, far below the 100 ppmv maximum allowable workplace concentration. The developed FastGC-PTR-MS can be used for rapid qualitative and quantitative detection of butanol isomers in latex paint. The new equipment has the potential to play an important role in indoor environmental safety applications.

Purpose: This study evaluated the central nervous system (CNS) pharmacokinetics and target engagement of lapatinib, neratinib, and tucatinib in patients with cancer, using a physiologically based pharmacokinetic (PBPK) modeling approach. Experimental Design: Drug-specific parameters for in vitro metabolism, binding to plasma proteins and brain tissues, transcellular passive permeability, and interactions with efflux transporters were determined. Whole-body PBPK models integrated with a 4-compartment permeability-limited brain model was developed and verified for predicting plasma and CNS pharmacokinetics. Target engagement ratio (TER), defined as the ratio of the average steady-state unbound drug brain concentration (Css,ave,br) to in vitro IC50 for HER2 inhibition, was used as a predictor of intracranial efficacy. Results: PBPK models predicted that following 1 cycle of standard dosing, tucatinib and lapatinib achieved similar Css,ave,br (14.5 vs. 16.8 nmol/L), while neratinib Css,ave,br (0.68 nmol/L) was 20-fold lower. Tucatinib and neratinib were equally potent for HER2 inhibition (IC50, 6.9 vs. 5.6 nmol/L), while lapatinib was less potent (IC50, 109 nmol/L). The model-predicted population mean TER in the human normal brain was 2.1 for tucatinib, but < 0.20 for lapatinib and neratinib. Conclusions: The PBPK modeling suggests that tucatinib induces sufficient HER2 inhibition (TER > 2.0) in not only brain metastases with a disrupted blood–brain barrier (BBB), but also micrometastases where the BBB largely remains intact. These findings, in line with available clinical pharmacokinetics and efficacy data, support the therapeutic value of tucatinib for treatment of brain metastases and warrant further clinical investigation for the prevention of brain metastases in patients with HER2-positive breast cancer.

These studies characterize the critical role of the Reduced Folate Carrier (RFC) and the Proton Coupled Folate Transporter (PCFT) as determinants of cancer cell reliance on mitochondrial vs cytosolic one carbon (C1) metabolism, to identify a unique susceptibility towards SHMT1 and SHMT2 inhibition in cancer cells. C1 metabolism is frequently reprogrammed in cancer cells to provide nucleotides, amino acids, and glutathione, and to maintain redox homeostasis for proliferation. The mitochondrial C1 converting enzymes serine hydroxymethyltransferase (SHMT) 2 and methylene tetrahydrofolate (THF) dehydrogenase 2 (MTHFD2) are among the top overexpressed metabolic enzymes in human cancers, suggesting these are important cancer-specific targets. We previously discovered novel 5-substituted pyrrolo[3,2-d]pyrimidine antifolates (with AGF347 being the lead) that potently inhibit mitochondrial SHMT2, as well as SHMT1. Folates are essential cofactors for C1 converting reactions; folates and antifolates primarily rely on the major facilitative folate transporters RFC and PCFT for internalization by tumor cells. In these studies, we explore the effects of folate transporter expression on the compartmentalization of C1 metabolism in the mitochondria and cytosol and the potential impact on SHMT1 and SHMT2 inhibition. We used a tetracycline inducible system for RFC expression in RFC/PCFT-null HeLa cells, with and without constitutive PCFT, and characterized the impact on transport and accumulation of folates and AGF347 in response to folate transporter expression. Increased accumulation of folates was observed with increasing RFC in the absence of PCFT. In the presence of PCFT, baseline folate accumulation was substantial and independent of RFC expression, indicating a major role of PCFT as a facilitative folate transporter. SHMT2 catalyzes the conversion of serine and THF to glycine and 5, 10-methylene THF in the mitochondria, while SHMT1 catalyzes the reverse reaction in the cytosol, producing THF and serine. To determine how folate transporter expression affects the C1 flux through SHMT1 vs SHMT2, [2,3,3-2H]serine tracer experiments were performed; increased mitochondrial C1 flux through SHMT2 was observed with increasing RFC in the absence of PCFT, whereas the mitochondrial flux through SHMT2 predominated in the presence of PCFT. By cell proliferation assays it was discovered that cells with lower RFC expression exhibit a hypersensitive phenotype towards AGF347 in the absence of PCFT, indicating a unique therapeutic opportunity for targeting SHMT forms in cancer cells with low folate transport activity. Here we identify RFC and PCFT as key determinants for the compartmentalization of C1 flux in the mitochondria vs the cytosol, in turn affecting the sensitivity of cancer cells towards SHMT inhibition. Citation Format: Mathew Joseph Schneider, Carrie O'connor, Xun Bao, Md. Junayed Nayeen, Zhanjun Hou, Jing Li, Aleem Gangjee, Larry H. Matherly. Levels of folate transporters impact the compartmentalization of one-carbon metabolism in the mitochondria vs cytosol providing a unique vulnerability to SHMT inhibition. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4903.