Antifolates are a class of drugs effective for treating malignant pleural mesothelioma (MPM). The majority of antifolates inhibit enzymes involved in purine and pyrimidine synthesis such as dihydrofolate reductase (DHFR), thymidylate synthase (TYMS), and glycinamide ribonucleotide formyltransferase (GART). In order to select the most suitable patients for effective therapy with drugs targeting specific metabolic pathways, there is a need for better predictive metabolic biomarkers. Antifolates can alter global metabolic pathways in MPM cells, yet the metabolic profile of treated cells has not yet been clearly elucidated. Here we found that MPM cell lines could be categorized into two groups according to their sensitivity or resistance to pemetrexed treatment. We show that pemetrexed susceptibility could be reversed and DNA synthesis rescued in drug-treated cells by the exogenous addition of the nucleotide precursors hypoxanthine and thymidine (HT). We observed that the expression of pemetrexed-targeted enzymes in resistant MPM cells was quantitatively lower than that seen in pemetrexed-sensitive cells. Metabolomic analysis revealed that glycine and choline, which are involved in one-carbon metabolism, were altered after drug treatment in pemetrexed-sensitive but not resistant MPM cells. The addition of HT upregulated the concentration of inosine monophosphate (IMP) in pemetrexed-sensitive MPM cells, indicating that the nucleic acid biosynthesis pathway is important for predicting the efficacy of pemetrexed in MPM cells. Our data provide evidence that may link therapeutic response to the regulation of metabolism, and points to potential biomarkers for informing clinical decisions regarding the most effective therapies for patients with MPM.

Summary Aphanothece sacrum (Sur.) Okada is a species of cyanobacteria found in Japan. Although it has been used in local cuisine in Kyushu, Japan, for 250 y, little is known about its beneficial effect as food. The daily intake of health beneficial phytochemicals is believed to be useful for preventing lifestyle-related diseases, such as diabetic cataracts. In this study, the inhibitory effect of freeze-dried A. sacrum (Asa) on the formation of diabetic cataracts (DCs) was evaluated. Type 1 diabetes was induced in mice using streptozotocin (STZ). The mice were divided into two groups: one was fed a normal diet (DM-control group) and the other was fed a diet containing 1% Asa (DM-Asa group). During the study, changes in blood glucose levels and the amount of food and water consumed were measured. After 3 mo, the amount of N ε -(carboxymethyl)lysine (CML), an oxidative stress marker, in the lens was measured using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Although the blood glucose levels (pϭ0.91) and food consumption did not significantly change in any group, the oral administration of Asa tended to suppress CML accumulation (pϭ0.15) and significantly inhibited the progression of cataractogenesis in the diabetic lens compared with that reported for the normal diet (pϭ0.009). These results suggested that the daily intake of A. sacrum prevents the pathogenesis of cataracts, and indicated that may reduce the number of DC patients.

Estrogen receptor (ER) positive breast cancer represents 75% of all breast cancers in women. Although patients with ER+ cancers receive endocrine therapies, more than 30% develop resistance and succumb to the disease, highlighting the need to understand endocrine resistance. Here we show an unexpected role for the cell polarity protein SCRIB as a tumor-promoter and a regulator of endocrine resistance in ER-positive breast cancer cells. SCRIB expression is induced by estrogen signaling in a MYC-dependent manner. SCRIB interacts with SLC3A2, a heteromeric component of leucine amino acid transporter SLC7A5. SLC3A2 binds to the N-terminus of SCRIB to facilitate the formation of SCRIB/SLC3A2/LLGL2/SLC7A5 quaternary complex required for membrane localization of the amino acid transporter complex. Both SCRIB and SLC3A2 are required for cell proliferation and tamoxifen resistance in ER+ cells identifying a new role for the SCRIB/SLC3A2 complex in ER+ breast cancer.

Approximately 20％ of diabetic patients develop diabetic cataracts. As lens proteins are known to be only slightly metabolized during the lifetime, cataracts are di‹cult to recover from once they have progressed. Therefore, the daily intake of natural compounds would be an important strategy for the prevention of diabetic cataracts. Aphanothece sacrum OKADA (Asa) is a freshwater blue-green algae endemic to Japan. It has been eaten since the Edo period in Kyushu. In this study, the inhibitory eŠects of Asa on the pathogenesis of diabetic cataracts were evaluated. Furthermore, the inhibitory eŠects of Asa on the formation of N e -(carboxymethyl) lysine (CML), an oxidation-dependent advanced glycation end-product, were also measured. After 3-month administration, the CML contents in the lens were measured by liquid chromatography tandem mass spectrometry using an internal standard of CML or lysine. Asa sig-niˆcantly inhibited the progression of cataractogenesis and accumulation of CML in diabetic lens compared with the normal diet group. These results suggested that daily intake of Asa reduces oxidative stress and prevents the pathogenesis of cataracts.