Hyperpolarized [1-13C]-pyruvate has shown tremendous promise as an agent for imaging tumor metabolism with unprecedented sensitivity and specificity. Imaging hyperpolarized substrates by magnetic resonance is unlike traditional MRI because signals are highly transient and their spatial distribution varies continuously over their observable lifetime. Therefore, new imaging approaches are needed to ensure optimal measurement under these circumstances. Constrained reconstruction algorithms can integrate prior information, including biophysical models of the substrate/target interaction, to reduce the amount of data that is required for image analysis and reconstruction. In this study, we show that metabolic MRI with hyperpolarized pyruvate is biased by tumor perfusion, and present a new pharmacokinetic model for hyperpolarized substrates that accounts for these effects. The suitability of this model is confirmed by statistical comparison to alternates using data from 55 dynamic spectroscopic measurements in normal animals and murine models of anaplastic thyroid cancer, glioblastoma, and triple-negative breast cancer. The kinetic model was then integrated into a constrained reconstruction algorithm and feasibility was tested using significantly under-sampled imaging data from tumor-bearing animals. Compared to naïve image reconstruction, this approach requires far fewer signal-depleting excitations and focuses analysis and reconstruction on new information that is uniquely available from hyperpolarized pyruvate and its metabolites, thus improving the reproducibility and accuracy of metabolic imaging measurements.

SUMMARY Altered energy metabolism is a cancer hallmark as malignant cells tailor their metabolic pathways to meet their energy requirements. Glucose and glutamine are the major nutrients that fuel cellular metabolism and the pathways utilizing these nutrients are often altered in cancer. Here, we show that the long ncRNA CCAT2, located at the 8q24 amplicon on cancer risk associated rs6983267 SNP, regulates cancer metabolism in vitro and in vivo, in an allele-specific manner by binding the Cleavage Factor I (CFIm) complex with distinct affinities for the two subunits (CFIm25 and CFIm68). The CCAT2 interaction with the CFIm complex fine-tunes the alternative splicing of Glutaminase (GLS) by selecting the poly(A) site in intron 14 of the precursor mRNA. These findings uncover a complex, allele-specific regulatory mechanism of cancer metabolism orchestrated by alleles of a long ncRNA.

Anaplastic thyroid carcinoma (ATC) is one of the most aggressive human malignancies. The aggressive behavior of ATC and its resistance to traditional treatment limit the efficacy of radiotherapy, chemotherapy, and surgery. The purpose of this study is aimed at enhancing the therapeutic efficacy of radiotherapy (RT) combined with photothermal therapy (PTT) in murine orthotopic model of ATC, based on our developed single radioactive copper sulfide (CuS) nanoparticle platform. We prepare a new dual-modality therapy for ATC consisting of a single-compartment nanoplatform, polyethylene glycol-coated [64Cu]CuS NPs, in which the radiotherapeutic property of 64Cu is combined with the plasmonic properties of CuS NPs. Mice with Hth83 ATC were treated with PEG[64Cu]CuS NPs and/or near infrared laser. Antitumor effects were assessed by tumor growth and animal survival. We found that in mice bearing orthotopic human Hth83 ATC tumors, micro-PET/CT imaging and biodistribution studies showed that about 50% of the injected dose of PEG-[64Cu]CuS NPs was retained in tumor 48 h after intratumoral injection. Human absorbed doses were calculated from biodistribution data. In antitumor experiments, tumor growth was delayed by PEG-[64Cu]CuS NP-mediated RT, PTT, and combined RT/PTT, with combined RT/PTT being most effective. In addition, combined RT/PTT significantly prolonged the survival of Hth83 tumor-bearing mice compared to no treatment, laser treatment alone, or NP treatment alone without producing acute toxic effects. These findings indicate that this single-compartment multifunctional NPs platform merits further development as a novel therapeutic agent for ATC.

Fluorinated heterocycles play an important role in pharmaceutical and agrochemical industries. Herein, we report on the synthesis of four types of fluorinated heterocycles via rhodium(III)-catalyzed C-H activation of arenes/alkenes and versatile coupling with 2,2-difluorovinyl tosylate. With N-OMe benzamide being a directing group (DG), the reaction delivered a monofluorinated alkene with the retention of the tosylate functionality. Subsequent one-pot acid treatment allowed the efficient synthesis of 4-fluoroisoquinolin-1(2H)-ones and 5-fluoropyridin-2(1H)-ones. When N-OPiv benzamides were used, however, [4 + 2] cyclization occurred to provide gem-difluorinated dihydroisoquinolin-1(2H)-ones. Synthetic applications have been demonstrated and the ready availability of both the arene and the coupling partner highlighted the synthetic potentials of these protocols. Mechanistically, these two processes share a common process involving N-H deprotonation, C-H activation, and olefin insertion to form a 7-membered rhodacycle. Thereafter, different reaction pathways featuring β-F elimination and C-N bond formation are followed on the basis of density functional theory (DFT) studies. These two pathways are DG-dependent and led to the open chain and cyclization products, respectively. The mechanistic rationale was supported by detailed DFT studies. In particular, the origins of the intriguing selectivity in the competing β-F elimination versus C-N bond formation were elucidated. It was found that β-F elimination is a facile event and proceeds via a syn-coplanar transition state with a low energy barrier. The C-N bond formation proceeds via a facile migratory insertion of the Rh-C(alkyl) into the Rh(V) amido species. In both reactions, the migratory insertion of the alkene is turnover-limiting, which stays in good agreement with the experimental studies.

Anaplastic thyroid carcinoma (ATC) accounts for over 50% of thyroid cancer mortality and is generally refractory to conventional treatment. Based on recent studies, we hypothesized that ATC metabolism can be targeted to improve response to chemo-radiotherapy. Eight established and authenticated ATC cell lines were sequenced at 140 sites contained within 26 commonly mutated genes to identify novel potential therapeutic targets. Cellular proliferation, energy and reducing potential stores were measured under conditions of specific nutrient deprivation. Tumor metabolism was evaluated using hyperpolarized 13C magnetic resonance imaging (MRI) in a murine orthotopic xenograft model of ATC. Sensitivity to chemotherapeutic agents and radiation (XRT) was assayed using cytotoxicity assays. We identified mutations in BRAF, NRAS and KIT but failed to identify generalized novel targets for therapeutic intervention. ATC cell lines exhibited a mesenchymal phenotype and generalized dependence on glucose for energy, reducing potential and survival. Glycolytic inhibition using 2-deoxyglucose (2-DG) sensitized ATC cells to conventional chemotherapy and external beam radiation. In vivo, 2-DG induced a transient, but significant reduction in ATC metabolic activity. Generalized dependence of ATC cells on glucose catabolism makes them susceptible to the sensitizing effects of 2-DG for radiation therapy and chemotherapy. Under in vivo conditions, 2-DG can inhibit ATC metabolism. However, the modest magnitude and transient nature of this effect suggest the need for anti-metabolic agents with more favorable pharmacodynamics to achieve therapeutic effects.