Expression of fatty acid synthase (FASN), the key enzyme in de novo synthesis of long-chain fatty acids, is normally low but increases in cancer. Consequently, FASN is a novel target for cancer therapy. However, because FASN inhibitors can lead to tumor stasis rather than shrinkage, noninvasive methods for assessing FASN inhibition are needed. To this end, we combined 1 H, 31 P, and 13 C magnetic resonance spectroscopy (MRS) (a) to monitor the metabolic consequences of FASN inhibition and (b) to identify MRS-detectable metabolic biomarkers of response. Treatment of PC-3 cells with the FASN inhibitor Orlistat for up to 48 h resulted in inhibition of FASN activity by 70%, correlating with 74% inhibition of fatty acid synthesis. Furthermore, we have determined that FASN inhibition results not only in lower phosphatidylcholine levels but also in a 59% drop in the phospholipid precursor phosphocholine (PCho). This drop resulted from inhibition in PCho synthesis as a result of a reduction in the cellular activity of its synthetic enzyme choline kinase.

Histone deacetylase (HDAC) inhibitors are new and promising antineoplastic agents. Current methods for monitoring early response rely on invasive biopsies or indirect blood-derived markers. Our goal was to develop a magnetic resonance spectroscopy (MRS) -based method to detect HDAC inhibition. The fluorinated lysine derivative Boc-Lys-(Tfa)-OH (BLT) was investigated as a 19 F MRS molecular marker of HDAC activity together with 31 P MRS of endogenous metabolites. In silico modeling of the BLT-HDAC interaction and in vitro MRS studies of BLT cleavage by HDAC confirmed BLT as a HDAC substrate. BLT did not affect cell viability or HDAC activity in PC3 prostate cancer cells. PC3 cells were treated, in the presence of BLT, with the HDAC inhibitor p-fluorosuberoylanilide hydroxamic acid (FSAHA) over the range of 0 to 10 Mmol/L, and HDAC activity and MRS spectra were monitored. Following FSAHA treatment, HDAC activity dropped, reaching 53% of control at 10 Mmol/L FSAHA. In parallel, a steady increase in intracellular BLT from 14 to 32 fmol/cell was observed. BLT levels negatively correlated with HDAC activity consistent with higher levels of uncleaved BLT in cells with inhibited HDAC. Phosphocholine, detected by 31

The anti-vascular function of platelet-derived growth factor receptor (PDGFR) inhibitor imatinib combined with paclitaxel has been demonstrated by invasive immunohistochemistry. The purpose of this study was 1. to noninvasively monitor the response to anti-PDGFR treatment and 2. to understand the underlying mechanism of this response. Thus, response to treatment was studied in a prostate cancer bone metastasis model using macromolecular (biotin-BSA-GdDTPA) dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). PC-3MM2 bone metastases that caused osteolysis and grew in neighboring muscle showed high blood volume fraction (fBV) and vascular permeability (PS) at the tumor periphery, compared to muscle tissue and intraosseous tumor. Imatinib alone or with paclitaxel significantly reduced PS by 35% (one-tailed paired t-test p=0.045) and 40% (p=0.0003) respectively, whereas paclitaxel alone or no treatment had no effect. Based on changes in PS we hypothesized that imatinib interferes with the signaling pathway of vascular endothelial growth factor (VEGF). This mechanism was verified by immunohistochemistry. It demonstrated reduced activation of both PDGFR-β and VEGFR2 in imatinib-treated mice. Our study therefore demonstrates that macromolecular DCE-MRI can be used to detect early vascular effects associated with response to therapy targeted to PDGFR and provides insight into the role played by VEGF in anti-PDGFR therapy.

Histone deacetylase inhibitors (HDACis) are emerging as promising and selective antitumor agents. However, HDACis can lead to tumor stasis rather than shrinkage, in which case, traditional imaging methods are not adequate to monitor response. Consequently, novel approaches are needed. We have shown in cells that (19)F magnetic resonance spectroscopy (MRS)-detectable levels of the HDAC substrate Boc-Lys-TFA-OH (BLT) are inversely correlated with HDAC activity. We extended our investigations to a tumor xenograft model. Following intraperitoneal injection of BLT, its accumulation within the tumor was monitored by in vivo (19)F MRS. In animals treated with the HDACi suberoylanilide hydroxamic acid (SAHA), tumoral BLT levels were higher by 77% and 132% on days 2 and 7 of treatment compared with pretreatment levels (n = 6; p < .05). In contrast, tumoral BLT levels remained unchanged in control animals and in normal tissue. Thus, (19)F MRS of BLT detected the effect of HDACi treatment as early as day 2 of treatment. Importantly, tumor size confirmed that SAHA treatment leads to inhibition of tumor growth. However, difference in tumor size reached significance only on day 6 of treatment. Thus, this work identifies BLT as a potential molecular imaging agent for the early noninvasive MRS detection of HDAC inhibition in vivo.

Objective Automated analysis of vaccine postmarketing surveillance narrative reports is important to understand the progression of rare but severe vaccine adverse events (AEs). This study implemented and evaluated state-of-the-art deep learning algorithms for named entity recognition to extract nervous system disorder-related events from vaccine safety reports. Materials and Methods We collected Guillain-Barré syndrome (GBS) related influenza vaccine safety reports from the Vaccine Adverse Event Reporting System (VAERS) from 1990 to 2016. VAERS reports were selected and manually annotated with major entities related to nervous system disorders, including, investigation, nervous_AE, other_AE, procedure, social_circumstance, and temporal_expression. A variety of conventional machine learning and deep learning algorithms were then evaluated for the extraction of the above entities. We further pretrained domain-specific BERT (Bidirectional Encoder Representations from Transformers) using VAERS reports (VAERS BERT) and compared its performance with existing models. Results and Conclusions Ninety-one VAERS reports were annotated, resulting in 2512 entities. The corpus was made publicly available to promote community efforts on vaccine AEs identification. Deep learning-based methods (eg, bi-long short-term memory and BERT models) outperformed conventional machine learning-based methods (ie, conditional random fields with extensive features). The BioBERT large model achieved the highest exact match F-1 scores on nervous_AE, procedure, social_circumstance, and temporal_expression; while VAERS BERT large models achieved the highest exact match F-1 scores on investigation and other_AE. An ensemble of these 2 models achieved the highest exact match microaveraged F-1 score at 0.6802 and the second highest lenient match microaveraged F-1 score at 0.8078 among peer models.

PurposeAbnormal fatty acid (FA) synthesis is one of the common features of cancer. Fatty acid synthase (FASN), a multifunctional enzyme playing a key role in biosynthesis of FA, is up-regulated in prostate, breast, and lung carcinomas. Orlistat is a FDA-approved anti-obesity drug that inhibits the thioesterase domain of FASN, interferes with cellular FA synthesis, can arrest tumor cell proliferation, and induces tumor cell apoptosis. The current study was aimed to investigate the metabolic changes associated with FASN inhibition by orlistat and to understand the molecular mechanisms behind the observed metabolic changes in non-small cell lung carcinoma (NSCLC) cell lines.ProceduresChanges in metabolite pools in four NSCLC cell lines (H441, H1975, H3255, and PC14) with different mutational profiles were studied using NMR spectroscopy before and after in vitro incubation with sub-toxic concentration of orlistat and [1-13C]d-glucose or [1,2-13C2]choline. In vitro radiotracer accumulation assays in cells were performed with [3H]acetate, [14C]fluoroacetate, and 2-deoxy-2-[18F]fluoro-d-glucose. In parallel, microarray profiling of genes involved in the regulation of carbohydrate and lipid metabolism was performed.ResultsIn orlistat-treated NSCLC cells, FASN inhibition results in characteristic changes in intermediary metabolites (FAs, choline, phospholipids, and TCA cycle metabolites) as observed by magnetic resonance spectroscopy. Further, FASN inhibition by orlistat induces multiple adaptive changes in FA synthetic pathway and associated metabolic pathways, including induction of ketone metabolism and glutaminolysis, as well as the up-regulation of 5' adenosine monophosphate-activated protein kinase.ConclusionsThese observed changes in metabolic pools in orlistat-treated cells demonstrate the critical role of fatty acid de novo synthesis and metabolism for cellular energy production, especially in tumor cells with low glycolytic activity, which goes beyond the widely accepted concept that FA synthesis is important for cell membrane biosynthesis in rapidly proliferating tumor cells.Electronic supplementary materialThe online version of this article (doi:10.1007/s11307-012-0587-6) contains supplementary material, which is available to authorized users.

Brachytherapy, a radiotherapy technique for treating prostate cancer, involves the implantation of numerous radioactive seeds into the prostate. While the implanted seeds can be easily identified on a CT image, distinguishing the prostate and surrounding soft tissues is not as straightforward. Magnetic Resonance Imaging (MRI) offers superior anatomical delineation, but the seeds appear as dark voids and are difficult to identify, thus creating a conundrum. Cobalt dichloride-N-acetyl-cysteine (C4) has previously been shown to be promising as an encapsulated contrast agent marker. We performed spin-lattice relaxation time (T1) and spin-spin relaxation time (T2) measurements of C4 solutions with varying cobalt dichloride concentrations to determine the corresponding relaxivities, r1 and r2. These relaxation parameters were investigated at different field strengths, temperatures and orientations. T1 measurements obtained at 1.5 T and 3.0 T, as well as at room and body temperature, showed that r1 is field-independent and temperature-independent. Conversely, the T2 values at 3.0 T were shorter than at 1.5 T, while the T2 values at body temperature were slightly higher than at room temperature. By examining the relaxivities with the C4 vials aligned in three different planes, we found no orientation-dependence. With these relaxation characteristics, we aim to develop pulse sequences that will enhance the C4 signal against prostatic stroma. Ultimately, the use of C4 as a positive contrast agent marker will encourage the use of MRI to obtain an accurate representation of the radiation dose delivered to the prostate and surrounding normal anatomical structures.

δ‐Aminolevulinic acid–photodynamic therapy (ALA‐PDT) has emerged as a useful technique in the treatment of superficial basal cell carcinoma, actinic keratosis, squamous cell carcinoma and tumors of other organs. Earlier reports mention that there is reappearance of protoporphyrin IX (PpIX) after photoirradiation of tumors. This property of reappearance of PpIX is being utilized to treat nodular tumors by fractionated light dose delivery. However, there is still no unanimously accepted reason for this reappearance phenomenon and the rate of resynthesis after PDT. On account of this, studies are carried out on the estimation of the pharmacokinetics of the ALA‐induced PpIX in mice tumor models and the surrounding normal tissues before and after PDT. Further, a mathematical model based on a multiple compartment system is proposed to estimate the rate parameter for the diffusion of PpIX from the surrounding normal tissues into the tumor tissue (km) caused by photobleaching during PDT with irradiating fluences of 36.0 and 57.6 J/cm2. The km value at two different fluences, 36.0 and 57.6 J/cm2, are estimated as 3.0636 ± 0.7083 h−1 and 6.9231 ± 2.17651 h−1, respectively. Further, the rate parameter for the cleavage and efflux of ALA (k1) and the rate parameter for the evasion of PpIX from the tumor tissues after PDT (kt) were also estimated by fitting the experimental data to the developed mathematical model. The statistical significance of the estimated parameters was determined using Student's t‐test. The experimental results and the rate parameters obtained using the proposed compartment model suggest that in addition to the earlier reported reasons, the invasion or diffusion of PpIX from the surrounding tissues to the tumor tissues after photoirradiation might also contribute to the reappearance of PpIX after PDT.