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Vitamins
Published in John K. DiBaise, Carol Rees Parrish, Jon S. Thompson, Short Bowel Syndrome Practical Approach to Management, 2017
Folic acid (folate) functions as a coenzyme in DNA and amino acid metabolism. It participates in many metabolic pathways by contributing single carbon units [51]. Folate is required for normal hematopoietic and neurologic function. It is absorbed in the jejunum by a proton-coupled folate transporter. Zinc deficiency, alcohol consumption, and intestinal lumen pH >6 can limit folate absorption [12,51]. Patients with bypass or resection of the proximal jejunum are at risk of developing folate deficiency. Megaloblastic anemia is the main clinical manifestation of folate deficiency. It is rare in patients with SBS because dietary folate, found in enriched grain products, fruits, and vegetables, is easily absorbed in the proximal bowel and folate production by enteric bacteria is readily absorbed by the host.
RX-3117 (fluorocyclopentenyl cytosine): a novel specific antimetabolite for selective cancer treatment
Published in Expert Opinion on Investigational Drugs, 2019
Beatrice Balboni, Btissame El Hassouni, Richard J. Honeywell, Dzjemma Sarkisjan, Elisa Giovannetti, Julie Poore, Callie Heaton, Christine Peterson, Ely Benaim, Young B. Lee, Deog J. Kim, Godefridus J. Peters
An interesting aspect of the mechanism of action of RX-3117 is the inhibition of DNA methyltransferase 1 (DNMT1) [12,14], but not DNMT3a. Inhibition of DNMT1 has been demonstrated in different cancer cell lines and was related to their sensitivity to the drug. DNMT1 is crucial for maintenance methylation [30]. Different RX-3117 concentrations were needed in various cell lines to reach the same level of DNMT1 suppression. Interestingly, this effect was predominantly noticed at the protein level, since the effect on mRNA levels was less [31]. In a comparison with aza-CdR and aza-CR as reference hypomethylation agents, it was demonstrated that the decrease in DNMT1 levels exerts a functional effect as well. Methylation usually leads to suppression of the promoter of a number of genes; hypomethylation will result in the activation of these genes, as has been demonstrated for genes such as O-methylguanine DNA methyltransferase and tumor suppressor genes [32]. The proton-coupled folate transporter not only showed an increased protein and gene expression, but also an increased transport activity, similar to aza-CR and aza-CdR. Moreover, treatment with RX-3117 led to a decrease in overall methylation of the DNA.
Anti-proliferate and apoptosis triggering potential of methotrexate-transferrin conjugate encapsulated PLGA nanoparticles with enhanced cellular uptake by high-affinity folate receptors
Published in Artificial Cells, Nanomedicine, and Biotechnology, 2018
Ankush Parmar, Atul Jain, Shivani Uppal, S. K. Mehta, Khuswinder Kaur, Bhupinder Singh, Rajat Sandhir, Shweta Sharma
Folic acid (FA-vitamin B9) commonly abbreviated as folate (oxidized form of folic acid) is an essential vitamin, obligatory for successful completion of one carbon transfer reactions in numerous metabolic pathways [15]. Additionally, folic acid plays a vital role in catalysing the bio-synthesis of nucleotide bases and acts as a precursor material for fetching the appetite of proliferating cells. Cellular uptake of folic acid takes place through three major routes, viz [15];Proton-coupled folate transporter (PCFT/SLC46A1): responsible for intestinal uptake of FA under different physiological acidic pH.Reduced folate carrier (RFC/SLC19A1): responsible for ubiquitous uptake of FA by varied tissues under different physiological pH.Folate transporters (FRs): responsible for receptor-mediated endocytosis of FA.
Splicing deregulation, microRNA and notch aberrations: fighting the three-headed dog to overcome drug resistance in malignant mesothelioma
Published in Expert Review of Clinical Pharmacology, 2022
Dario P. Anobile, Giulia Montenovo, Camilla Pecoraro, Marika Franczak, Widad Ait Iddouch, Godefridus J Peters, Chiara Riganti, Elisa Giovannetti
As for the therapeutic agents of choice, the standard first-line chemotherapy treatment in MPM has been cisplatin and pemetrexed for more than 15 years [32], but resistance represents one of the most important challenges in MPM treatment [33]. The drug–drug interactions, cross resistance, and resistance mechanisms regarding these key drugs are not well understood in MPM [34]. However, only a few studies identified potential predictors of responsiveness to chemotherapy such as increased gene expression of thymidylate synthase and reduced expression of proton-coupled folate transporter (PCFT), which can cause resistance to pemetrexed [35,36].