Mirvetuximab Soravtansine in FRα-Positive, Platinum-Resistant Ovarian Cancer.

BACKGROUND: Mirvetuximab soravtansine-gynx (MIRV), a first-in-class antibody-drug conjugate targeting folate receptor α (FRα), is approved for the treatment of platinum-resistant ovarian cancer in the United States. METHODS: We conducted a phase 3, global, confirmatory, open-label, randomized, controlled trial to compare the efficacy and safety of MIRV with the investigator's choice of chemotherapy in the treatment of platinum-resistant, high-grade serous ovarian cancer. Participants who had previously received one to three lines of therapy and had high FRα tumor expression (≥75% of cells with ≥2+ staining intensity) were randomly assigned in a 1:1 ratio to receive MIRV (6 mg per kilogram of adjusted ideal body weight every 3 weeks) or chemotherapy (paclitaxel, pegylated liposomal doxorubicin, or topotecan). The primary end point was investigator-assessed progression-free survival; key secondary analytic end points included objective response, overall survival, and participant-reported outcomes. RESULTS: A total of 453 participants underwent randomization; 227 were assigned to the MIRV group and 226 to the chemotherapy group. The median progression-free survival was 5.62 months (95% confidence interval [CI], 4.34 to 5.95) with MIRV and 3.98 months (95% CI, 2.86 to 4.47) with chemotherapy (P<0.001). An objective response occurred in 42.3% of the participants in the MIRV group and in 15.9% of those in the chemotherapy group (odds ratio, 3.81; 95% CI, 2.44 to 5.94; P<0.001). Overall survival was significantly longer with MIRV than with chemotherapy (median, 16.46 months vs. 12.75 months; hazard ratio for death, 0.67; 95% CI, 0.50 to 0.89; P = 0.005). During the treatment period, fewer adverse events of grade 3 or higher occurred with MIRV than with chemotherapy (41.7% vs. 54.1%), as did serious adverse events of any grade (23.9% vs. 32.9%) and events leading to discontinuation (9.2% vs. 15.9%). CONCLUSIONS: Among participants with platinum-resistant, FRα-positive ovarian cancer, treatment with MIRV showed a significant benefit over chemotherapy with respect to progression-free and overall survival and objective response. (Funded by ImmunoGen; MIRASOL ClinicalTrials.gov number, NCT04209855.).

Folate regulation of planar cell polarity pathway and F-actin through folate receptor alpha.

Folate deficiency contribute to neural tube defects (NTDs) which could be rescued by folate supplementation. However, the underlying mechanisms are still not fully understood. Besides, there is considerable controversy concerning the forms of folate used for supplementation. To address this controversy, we prepared culture medium with different forms of folate, folic acid (FA), and 5-methyltetrahydrofolate (5mTHF), at concentrations of 5 µM, 500 nM, 50 nM, and folate free, respectively. Mouse embryonic fibroblasts (MEFs) were treated with different folates continuously for three passages, and cell proliferation and F-actin were monitored. We determined that compared to 5mTHF, FA showed stronger effects on promoting cell proliferation and F-actin formation. We also found that FOLR1 protein level was positively regulated by folate concentration and the non-canonical Wnt/planar cell polarity (PCP) pathway signaling was significantly enriched among different folate conditions in RNA-sequencing analyses. We demonstrated for the first time that FOLR1 could promote the transcription of Vangl2, one of PCP core genes. The transcription of Vangl2 was down-regulated under folate-deficient condition, which resulted in a decrease in PCP activity and F-actin formation. In summary, we identified a distinct advantage of FA in cell proliferation and F-actin formation over 5mTHF, as well as demonstrating that FOLR1 could promote transcription of Vangl2 and provide a new mechanism by which folate deficiency can contribute to the etiology of NTDs.

Folate receptor α deficiency - Myelin-sensitive MRI as a reliable biomarker to monitor the efficacy and long-term outcome of a new therapeutic approach.

Cerebral folate transport deficiency, caused by a genetic defect in folate receptor α, is a devastating neurometabolic disorder that, if untreated, leads to epileptic encephalopathy, psychomotor decline and hypomyelination. Currently, there are limited data on effective dosage and duration of treatment, though early diagnosis and therapy with folinic acid appears critical. The aim of this long-term study was to identify new therapeutic approaches and novel biomarkers for assessing efficacy, focusing on myelin-sensitive MRI. Clinical, biochemical, structural and quantitative MRI parameters of seven patients with genetically confirmed folate receptor α deficiency were acquired over 13 years. Multimodal MRI approaches comprised MR-spectroscopy (MRS), magnetization transfer (MTI) and diffusion tensor imaging (DTI) sequences. Patients started oral treatment immediately following diagnosis or in an interval of up to 2.5 years. Escalation to intravenous and intrathecal administration was performed in the absence of effects. Five patients improved, one with a presymptomatic start of therapy remained symptom-free, and one with inconsistent treatment deteriorated. While CSF 5-methyltetrahydrofolate and MRS parameters normalized immediately after therapy initiation, myelin-sensitive MTI and DTI measures correlated with gradual clinical improvement and ongoing myelination under therapy. Early initiation of treatment at sufficient doses, considering early intrathecal applications, is critical for favorable outcome. The majority of patients showed clinical improvements that correlated best with MTI parameters, allowing individualized monitoring of myelination recovery. Presymptomatic therapy seems to ensure normal development and warrants newborn screening. Furthermore, the quantitative parameters of myelin-sensitive MRI for therapy assessments can now be used for hypomyelination disorders in general.

Folate Receptor Alpha-A Novel Approach to Cancer Therapy.

Folate receptor α (FR) was discovered many decades ago, along with drugs that target intracellular folate metabolism, such as pemetrexed and methotrexate. Folate is taken up by the cell via this receptor, which also targeted by many cancer agents due to the over-expression of the receptor by cancer cells. FR is a membrane-bound glycosyl-phosphatidylinositol (GPI) anchor glycoprotein encoded by the folate receptor 1 (FOLR1) gene. FR plays a significant role in DNA synthesis, cell proliferation, DNA repair, and intracellular signaling, all of which are essential for tumorigenesis. FR is more prevalent in cancer cells compared to normal tissues, which makes it an excellent target for oncologic therapeutics. FRα is found in many cancer types, including ovarian cancer, non-small-cell lung cancer (NSCLC), and colon cancer. FR is widely used in antibody drug conjugates, small-molecule-drug conjugates, and chimeric antigen-receptor T cells. Current oncolytic therapeutics include mirvetuximab soravtansine, and ongoing clinical trials are underway to investigate chimeric antigen receptor T cells (CAR-T cells) and vaccines. Additionally, FRα has been used in a myriad of other applications, including as a tool in the identification of tumor types, and as a prognostic marker, as a surrogate of chemotherapy resistance. As such, FRα identification has become an essential part of precision medicine.

Developing Folate-Conjugated miR-34a Therapeutic for Prostate Cancer: Challenges and Promises.

Prostate cancer (PCa) remains a common cancer with high mortality in men due to its heterogeneity and the emergence of drug resistance. A critical factor contributing to its lethality is the presence of prostate cancer stem cells (PCSCs), which can self-renew, long-term propagate tumors, and mediate treatment resistance. MicroRNA-34a (miR-34a) has shown promise as an anti-PCSC therapeutic by targeting critical molecules involved in cancer stem cell (CSC) survival and functions. Despite extensive efforts, the development of miR-34a therapeutics still faces challenges, including non-specific delivery and delivery-associated toxicity. One emerging delivery approach is ligand-mediated conjugation, aiming to achieve specific delivery of miR-34a to cancer cells, thereby enhancing efficacy while minimizing toxicity. Folate-conjugated miR-34a (folate-miR-34a) has demonstrated promising anti-tumor efficacy in breast and lung cancers by targeting folate receptor α (FOLR1). Here, we first show that miR-34a, a TP53 transcriptional target, is reduced in PCa that harbors TP53 loss or mutations and that miR-34a mimic, when transfected into PCa cells, downregulated multiple miR-34a targets and inhibited cell growth. When exploring the therapeutic potential of folate-miR-34a, we found that folate-miR-34a exhibited impressive inhibitory effects on breast, ovarian, and cervical cancer cells but showed minimal effects on and targeted delivery to PCa cells due to a lack of appreciable expression of FOLR1 in PCa cells. Folate-miR-34a also did not display any apparent effect on PCa cells expressing prostate-specific membrane antigen (PMSA) despite the reported folate's binding capability to PSMA. These results highlight challenges in the specific delivery of folate-miR-34a to PCa due to a lack of target (receptor) expression. Our study offers novel insights into the challenges and promises within the field and casts light on the development of ligand-conjugated miR-34a therapeutics for PCa.

Reanalysis of exome sequencing data reveals a treatable neurometabolic origin in two previously undiagnosed siblings with neurodevelopmental disorder.

Neurodevelopmental disorders (NDDs) have broad heterogeneity both clinically and genetically. Inborn errors of metabolism can be one of the reasons of neurodevelopmental disruption causing specific NDDs. Although there is tremendous advance in molecular identification via next-generation sequencing (NGS), there are still many unsolved patients with NDD. Reanalysis of NGS data with different pipelines can at least partially accomplish this challenge. Herein, we report clinic and genetic components of an adult sib-pair with an undiagnosed NDD condition, which has been solved through reanalysis of whole-exome sequencing (WES). Parallel analysis of SNP-based genotyping and WES was performed to focus on variants only in loci with positive logarithm of the odds scores. WES data was analyzed through three different pipelines with two distinct bed files. Reanalysis of WES data led us to detect a homozygous FOLR1 variant (ENST00000393676.5:c.610C > T, p.(Arg204Ter), rs952165627) in the affected sib-pair. Surprisingly, the variant could not be detected in the first analysis as the variant region is not included in the first bed file which may frequently be used. Biochemical tests of CSF have confirmed the genetic analysis, CSF folic acid levels were detected low in sib-pair, and intravenous folinic acid treatment improved the disease course for the first 6 months of follow-up even at late diagnosis age. Although combined analysis of SNP-based genotyping and WES is a powerful tool to reveal the genetic components of heterogeneous diseases, reanalysis of genome data still should be considered in unsolved patients. Also, biochemical screening helps us to decipher undiagnosed NDD that may be a treatable neurometabolic condition.

A Paternal Methylation Error in the Congenital Hydrocephalic Texas (H-Tx) Rat Is Partially Rescued with Natural Folate Supplements.

Folate deficiencies, folate imbalance and associated abnormal methylation are associated with birth defects, developmental delays, neurological conditions and diseases. In the hydrocephalic Texas (H-Tx) rat, 10-formyl tetrahydrofolate dehydrogenase (FDH) is reduced or absent from the CSF and the nuclei of cells in the brain and liver and this is correlated with decreased DNA methylation. In the present study, we tested whether impaired folate metabolism or methylation exists in sexually mature, unaffected H-Tx rats, which may explain the propagation of hydrocephalus in their offspring. We compared normal Sprague Dawley (SD, n = 6) rats with untreated H-Tx (uH-Tx, n = 6 and folate-treated H-Tx (TrH-Tx, n = 4). Structural abnormalities were observed in the testis of uH-Tx rats, with decreased methylation, increased demethylation, and cell death, particularly of sperm. FDH and FRα protein expression was increased in uH-Tx males but not in folate-treated males but tissue folate levels were unchanged. 5-Methylcytosine was significantly reduced in untreated and partially restored in treated individuals, while 5-hydroxymethylcytosine was not significantly changed. Similarly, a decrease in DNA-methyltransferase-1 expression in uH-Tx rats was partially reversed with treatment. The data expose a significant germline methylation error in unaffected adult male H-Tx rats from which hydrocephalic offspring are obtained. Reduced methylation in the testis and sperm was partially recovered by treatment with folate supplements leading us to conclude that this neurological disorder may not be completely eradicated by maternal supplementation alone.

CIC missense variants contribute to susceptibility for spina bifida.

Neural tube defects (NTDs) are congenital malformations resulting from abnormal embryonic development of the brain, spine, or spinal column. The genetic etiology of human NTDs remains poorly understood despite intensive investigation. CIC, homolog of the Capicua transcription repressor, has been reported to interact with ataxin-1 (ATXN1) and participate in the pathogenesis of spinocerebellar ataxia type 1. Our previous study demonstrated that CIC loss of function (LoF) variants contributed to the cerebral folate deficiency syndrome by downregulating folate receptor 1 (FOLR1) expression. Given the importance of folate transport in neural tube formation, we hypothesized that CIC variants could contribute to increased risk for NTDs by depressing embryonic folate concentrations. In this study, we examined CIC variants from whole-genome sequencing (WGS) data of 140 isolated spina bifida cases and identified eight missense variants of CIC gene. We tested the pathogenicity of the observed variants through multiple in vitro experiments. We determined that CIC variants decreased the FOLR1 protein level and planar cell polarity (PCP) pathway signaling in a human cell line (HeLa). In a murine cell line (NIH3T3), CIC loss of function variants downregulated PCP signaling. Taken together, this study provides evidence supporting CIC as a risk gene for human NTD.

Genetic and clinical landscape of childhood cerebellar hypoplasia and atrophy.

PURPOSE: Cerebellar hypoplasia and atrophy (CBHA) in children is an extremely heterogeneous group of disorders, but few comprehensive genetic studies have been reported. Comprehensive genetic analysis of CBHA patients may help differentiating atrophy and hypoplasia and potentially improve their prognostic aspects. METHODS: Patients with CBHA in 176 families were genetically examined using exome sequencing. Patients with disease-causing variants were clinically evaluated. RESULTS: Disease-causing variants were identified in 96 of the 176 families (54.5%). After excluding 6 families, 48 patients from 42 families were categorized as having syndromic associations with CBHA, whereas the remaining 51 patients from 48 families had isolated CBHA. In 51 patients, 26 aberrant genes were identified, of which, 20 (76.9%) caused disease in 1 family each. The most prevalent genes were CACNA1A, ITPR1, and KIF1A. Of the 26 aberrant genes, 21 and 1 were functionally annotated to atrophy and hypoplasia, respectively. CBHA+S was more clinically severe than CBHA-S. Notably, ARG1 and FOLR1 variants were identified in 2 families, leading to medical treatments. CONCLUSION: A wide genetic and clinical diversity of CBHA was revealed through exome sequencing in this cohort, which highlights the importance of comprehensive genetic analyses. Furthermore, molecular-based treatment was available for 2 families.

CIC de novo loss of function variants contribute to cerebral folate deficiency by downregulating FOLR1 expression.

Background Cerebral folate deficiency (CFD) syndrome is characterised by a low concentration of 5-methyltetrahydrofolate in cerebrospinal fluid, while folate levels in plasma and red blood cells are in the low normal range. Mutations in several folate pathway genes, including FOLR1 (folate receptor alpha, FRα), DHFR (dihydrofolate reductase) and PCFT (proton coupled folate transporter) have been previously identified in patients with CFD. Methods In an effort to identify causal mutations for CFD, we performed whole exome sequencing analysis on eight CFD trios and identified eight de novo mutations in seven trios. Results Notably, we found a de novo stop gain mutation in the capicua (CIC) gene. Using 48 sporadic CFD samples as a validation cohort, we identified three additional rare variants in CIC that are putatively deleterious mutations. Functional analysis indicates that CIC binds to an octameric sequence in the promoter regions of folate transport genes: FOLR1, PCFT and reduced folate carrier (Slc19A1; RFC1). The CIC nonsense variant (p.R353X) downregulated FOLR1 expression in HeLa cells as well as in the induced pluripotent stem cell (iPSCs) derived from the original CFD proband. Folate binding assay demonstrated that the p.R353X variant decreased cellular binding of folic acid in cells. Conclusion This study indicates that CIC loss of function variants can contribute to the genetic aetiology of CFD through regulating FOLR1 expression. Our study described the first mutations in a non-folate pathway gene that can contribute to the aetiology of CFD.

Upregulation of reduced folate carrier by vitamin D enhances brain folate uptake in mice lacking folate receptor alpha.

Folates are critical for central nervous system function. Folate transport is mediated by 3 major pathways, reduced folate carrier (RFC), proton-coupled folate transporter (PCFT), and folate receptor alpha (FRα/Folr1), known to be regulated by ligand-activated nuclear receptors. Cerebral folate delivery primarily occurs at the choroid plexus through FRα and PCFT; inactivation of these transport systems can result in very low folate levels in the cerebrospinal fluid causing childhood neurodegenerative disorders. These disorders have devastating effects in young children, and current therapeutic approaches are not sufficiently effective. Our group has previously reported in vitro that functional expression of RFC at the blood-brain barrier (BBB) and its upregulation by the vitamin D nuclear receptor (VDR) could provide an alternative route for brain folate uptake. In this study, we further demonstrated in vivo, using Folr1 knockout (KO) mice, that loss of FRα led to a substantial decrease of folate delivery to the brain and that pretreatment of Folr1 KO mice with the VDR activating ligand, calcitriol (1,25-dihydroxyvitamin D3), resulted in over a 6-fold increase in [13C5]-5-formyltetrahydrofolate ([13C5]-5-formylTHF) concentration in brain tissues, with levels comparable to wild-type animals. Brain-to-plasma concentration ratio of [13C5]-5-formylTHF was also significantly higher in calcitriol-treated Folr1 KO mice (15-fold), indicating a remarkable enhancement in brain folate delivery. These findings demonstrate that augmenting RFC functional expression at the BBB could effectively compensate for the loss of Folr1-mediated folate uptake at the choroid plexus, providing a therapeutic approach for neurometabolic disorders caused by defective brain folate transport.

Profiling the Influence of Gene Variants Related to Folate-Mediated One-Carbon Metabolism on the Outcome of In Vitro Fertilization (IVF) with Donor Oocytes in Recipients Receiving Folic Acid Fortification.

Nutritional status and gene polymorphisms of one-carbon metabolism confer a well-known interaction that in pregnant women may affect embryo viability and the health of the newborn. Folate metabolism directly impacts nucleotide synthesis and methylation, which is of increasing interest in the reproductive medicine field. Studies assessing the genetic influence of folate metabolism on IVF treatments have currently been performed in women using their own oocytes. Most of these patients seeking to have a child or undergoing IVF treatments are advised to preventively intake folate supplies that restore known metabolic imbalances, but the treatments could lead to the promotion of specific enzymes in specific women, depending on their genetic variance. In the present study, we assess the influence of candidate gene variants related to folate metabolism, such as Serine Hydroxymethyltransferase 1 SHMT1 (rs1979276 and rs1979277), Betaine-Homocysteine S-Methyltransferase BHMT (rs3733890), Methionine synthase reductase MTRR (rs1801394), Methylenetetrahydrofolate reductase MTHFR (rs1801131 and rs1801133), methionine synthase MTR (rs12749581), ATP Binding Cassette Subfamily B Member 1 ABCB1 (rs1045642) and folate receptor alpha FOLR1 (rs2071010) on the success of IVF treatment performed in women being recipients of donated oocytes. The implication of such gene variants seems to have no direct impact on pregnancy consecution after IVF; however, several gene variants could influence pregnancy loss events or pregnancy maintenance, as consequence of folic acid fortification.

Association of periconceptional folate supplements and FOLR1 and FOLR2 gene polymorphisms with risk of congenital heart disease in offspring: A hospital-based case-control study. / æ¯äº²å›´å­•æœŸæœç”¨å¶é ¸åŠFOLR1和FOLR2åŸºå› å¤šæ€æ€§ä¸Žå­ä»£å ˆå¤©æ€§å¿ƒè„ç— å ³è”çš„ç— ä¾‹å¯¹ç §ç ”ç©¶.

OBJECTIVES: Maternal periconceptional folic acid supplement is by far the most effective primary prevention strategy to reduce the incidence of congenital heart disease (CHD) in offspring. It was revealed that the underlying mechanisms are complex, including a combination of genetic and environmental factors. The purpose of this study is to investigate the association between periconceptional folic acid supplement, the genetic polymorphisms of maternal folic acid receptor 1 gene (FOLR1) and folic acid receptor 2 gene (FOLR2) and the impact of their interaction on the risk of CHD in offspring, and to provide epidemiological evidence for individualized folic acid dosing in hygienic counseling. METHODS: A case-control study on 569 mothers of CHD infants and 652 mothers of health controls was performed. The interesting points were periconceptional folate supplements, single nucleotide polymorphisms (SNPs) of maternal FOLR1 gene and FOLR2 gene. RESULTS: Mothers who took folate in the periconceptional period were observed a decreased risk of CHD [adjusted odds ratio (aOR)=0.58, 95% CI 0.35 to 0.95]. Our study also found that polymorphisms of maternal FOLR1 gene at rs2071010 (G/A vs G/G: aOR=0.67, 95% CI 0.47 to 0.96) and FOLR2 gene at rs514933 (T/C vs T/T: aOR=0.60, 95% CI 0.43 to 0.84; C/C vs T/T: aOR=0.55, 95% CI 0.33 to 0.90; the dominant model: T/C+ C/C vs T/T: aOR=0.59, 95% CI 0.43 to 0.81; and the addictive model: C/C vs T/C vs T/T: aOR=0.70, 95% CI 0.56 to 0.88) were significantly associated with lower risk of CHD [all P<0.05, false discovery rate P value (FDR_P)<0.1]. Besides, significant interaction between periconceptional folate supplements and rs2071010 G→A (aOR=0.59, 95% CI 0.41-0.86) and rs514933 T→C (aOR=0.52, 95% CI 0.37 to 0.74) on CHD risk were observed (all P<0.05, FDR_P<0.1). CONCLUSIONS: Periconceptional folate supplements, polymorphisms of FOLR1 gene and FOLR2 gene and their interactions are significantly associated with risk of CHD. However, more studies in different ethnic populations with a larger sample and prospective designs are required to confirm our findings.

Quantitative proteomics identifies FOLR1 to drive sorafenib resistance via activating autophagy in hepatocellular carcinoma cells.

Sorafenib is commonly used to treat advanced human hepatocellular carcinoma (HCC). However, clinical efficacy has been limited by drug resistance. In this study, we used label-free quantitative proteomic analysis to systematically investigate the underlying mechanisms of sorafenib resistance in HCC cells. A total of 1709 proteins were confidently quantified. Among them, 89 were differentially expressed and highly enriched in the processes of cell-cell adhesion, negative regulation of apoptosis, response to drug and metabolic processes involving in sorafenib resistance. Notably, folate receptor α (FOLR1) was found to be significantly upregulated in resistant HCC cells. In addition, in vitro studies showed that overexpression of FOLR1 decreased the sensitivity of HCC cells to sorafenib, whereas siRNA-directed knockdown of FOLR1 increased the sensitivity of HCC cells to sorafenib. Immunoprecipitation-mass spectrometry analysis suggested a strong link between FOLR1 and autophagy-related proteins. Further biological experiments found that FOLR1-related sorafenib resistance was accompanied by the activation of autophagy, whereas inhibition of autophagy significantly reduced FOLR1-induced cell resistance. These results suggest the driving role of FOLR1 in HCC resistance to sorafenib, which may be exerted through FOLR1-induced autophagy. Therefore, this study may provide new insights into understanding the mechanism of sorafenib resistance.

Fourth-generation chimeric antigen receptor T cells targeting folate receptor alpha antigen expressed on breast cancer cells for adoptive T cell therapy.

PURPOSE: Treatment of breast cancer (BC) by standard methods is effective in the early stage, but ineffective in the advanced stage of disease. To develop an adoptive T cell therapy for advanced and severe BC, we generated fourth-generation chimeric antigen receptor (CAR) T cells targeting folate receptor alpha antigen (FRα) expressed on BC cells, and preclinically evaluated their anti-BC activities. METHODS: The fourth-generation FRα-CAR T cells containing extracellular FRα-specific single-chain variable fragment (scFv) and three intracellular costimulatory domains (CD28, 4-1BB, and CD27) linked to CD3ζ were generated using a lentiviral system, and then were evaluated for their anti-BC activities in two-dimensional and three-dimensional (spheroid) cultures. RESULTS: When our fourth-generation FRα-CAR T cells were cocultured with FRα-expressing MDA-MB-231 BC cell line at an effector to target ratio of 20:1, these CAR T cells specifically lysed 88.7 ± 10.6% of the target cells. Interestingly, the cytotoxic lysis of FRα-CAR T cells was more pronounced in target cells with higher surface FRα expression. This specific cytotoxicity of the CAR T cells was not observed when cocultured with FRα-negative MCF10A normal breast-like cell line at the same ratio (34.3 ± 4.7%). When they were cocultured with MDA-MD-231 spheroid, the FRα-CAR T cells exhibited antitumor activity marked with spheroid size reduction and breakage. CONCLUSION: This proof-of-concept study thus shows the feasibility of using these fourth-generation FRα-CAR T cells for adoptive T cell therapy in BC.

Cerebral folate transporter deficiency syndrome in three siblings: Why genetic testing for developmental and epileptic encephalopathies should be performed early and include the FOLR1 gene.

Cerebral folate transporter deficiency syndrome, caused by FOLR-1 mutations is characterized by late infantile onset, severe developmental regression, epilepsy, and leukodystrophy. An extremely low concentration of 5-methyltetrahydrofolate in the cerebrospinal fluid provides a crucial clue to its diagnosis and is a treatment target. Oral or intravenous folinic acid (5-formyltetrahydrofolate) administration improves clinical symptoms and brain magnetic resonance imaging (MRI) findings. We describe three siblings carrying a novel homozygous FOLR1 nonsense mutation, that were referred due to intractable epilepsy and progressive neurological decline. Brain MRI showed hypomyelination and cerebellar atrophy. Folinic acid (oral and intravenous) supplementation, initiated after over 15 years illness, has failed to result in any sizeable clinical or neurophysiological improvement. Cerebral folate transport deficiency bears overlapping clinical features with many severe developmental encephalopathies. It is crucial to recognize FOLR1 signs and establish an early clinical and molecular diagnosis in order to provide timely folinic acid treatment and improve outcome.

Folate Receptor Alpha Is Preferentially Expressed in the Carcinoma Component of Endometrial Carcinosarcomas: A Potential Target for Adjuvant Therapy.

Carcinosarcomas (CSs) of the endometrium are biphasic malignancies, composed of high-grade carcinomatous and sarcomatous components. Surgical stage and pathologic characteristics are the most important prognostic findings, with a 5-yr survival of 15% to 30% in advance stage disease. Folate receptor alpha (FRA) overexpression has been observed in endometrial carcinomas and not yet studied in CSs. This study evaluates semiquantitative expression of FRA in both carcinomatous and sarcomatous components of CSs on whole tissue sections. Immunohistochemistry for FRA expression was performed and extent and intensity of staining were recorded for each case for both histologic components. A total of 46 cases were stained for FRA. The majority of these (40/46, 87%) showed FRA staining at variable intensity in the carcinomatous component, stronger in serous carcinomas and high-grade endometrioid, while only a small subset of tumors demonstrated weak staining in the sarcomatous component (2/46, 4.35%). CS is known to be associated with poor prognosis and adjuvant therapy is recommended even in low stage disease. Serous and high-grade endometrioid carcinomas are the most common carcinomatous components of CSs and are known to show consistently high FRA expression. Folate plays a role in tumor cell migration and loss of cellular adhesion, which are key steps in epithelial-mesenchymal transition, the process by which CS develops from carcinoma cells. Our study shows expression of FRA in the carcinomatous component of almost all CS cases (87%), further favoring FRA as a target for adjuvant treatment. While expression of FRA in the sarcomatous component was rarely observed, the carcinomatous component being associated with metastatic potential underscores the importance of anti-FRA therapy for systemic disease control.

Folate-appended cyclodextrin carrier targets ovarian cancer cells expressing the proton-coupled folate transporter.

Folate receptor alpha (FRα) is overexpressed in >80% of epithelial ovarian cancer (EOC). Accordingly, folate is attracting attention as a targeting ligand for EOC. For EOC patients, paclitaxel (PTX) is generally used as a first-line chemotherapeutic agent in combination with platinum-based drugs. Cyclodextrin (CyD) is a potential new formulation vehicle for PTX that could replace Cremophor-EL, a traditional formulation vehicle that causes significant side effects, including neutropenia. Several years ago, folate-appended ß-CyD (Fol-c1 -ß-CyD) was developed as an FRα-targeting drug carrier, but its efficacy as a treatment for EOC remains to be determined. In this study, we assessed the antitumor activity of PTX in Fol-c1 -ß-CyD (PTX/Fol-c1 -ß-CyD) in EOC-derived cell lines. We found that PTX/Fol-c1 -ß-CyD killed not only FRα-expressing cells but also FRα-negative cells. In the FRα-negative A2780 cells, knockdown of proton-coupled folate transporter (PCFT) significantly decreased the cytotoxicity of PTX/Fol-c1 -ß-CyD, whereas knockdown of FRα did not. By contrast, knockdown of either FRα or proton-coupled folate transporter (PCFT) decreased the cytotoxicity of PTX/Fol-c1 -ß-CyD in FRα-expressing SK-OV-3 cells. Furthermore, the cytotoxicity of PTX/Fol-c1 -ß-CyD in A2780 cells was increased at acidic pH, and this increase was suppressed by PCFT inhibitor. In mice intraperitoneally inoculated with FRα-expressing or PCFT-expressing EOC cells, intraperitoneal administration of PTX/Fol-c1 -ß-CyD significantly suppressed the growth of both types of EOC cells relative to PTX alone, without inducing a significant change in the neutrophil/white blood cell ratio. Our data suggest that Fol-c1 -ß-CyD targets not only FRα but also PCFT, and can efficiently deliver anticancer drugs to EOC cells in the peritoneal cavity.

Folate receptor 1 is necessary for neural plate cell apical constriction during Xenopus neural tube formation.

Folate supplementation prevents up to 70% of neural tube defects (NTDs), which result from a failure of neural tube closure during embryogenesis. The elucidation of the mechanisms underlying folate action has been challenging. This study introduces Xenopus laevis as a model to determine the cellular and molecular mechanisms involved in folate action during neural tube formation. We show that knockdown of folate receptor 1 (Folr1; also known as FRα) impairs neural tube formation and leads to NTDs. Folr1 knockdown in neural plate cells only is necessary and sufficient to induce NTDs. Folr1-deficient neural plate cells fail to constrict, resulting in widening of the neural plate midline and defective neural tube closure. Pharmacological inhibition of folate action by methotrexate during neurulation induces NTDs by inhibiting folate interaction with its uptake systems. Our findings support a model in which the folate receptor interacts with cell adhesion molecules, thus regulating the apical cell membrane remodeling and cytoskeletal dynamics necessary for neural plate folding. Further studies in this organism could unveil novel cellular and molecular events mediated by folate and lead to new ways of preventing NTDs.

Synthesis of folic acid functionalized terbium-doped dendritic fibrous nano-silica and Interaction with HEK 293 normal, MDA breast cancer and HT 29 colon cancer cells.

A novel folic acid functionalized terbium-doped dendritic fibrous nanoparticle (Tb@KCC-1-NH2 -FA) with high surface area was synthesized using a novel hydrothermal protocol. In the present work, we report the fluorescent Tb-doted nanomaterial with emission wavelength at 497 nm which confirms the formation of Tb@KCC-1-NH2 -FA. Synthesized nanoparticles were investigated through transmission electron microscope, field emission scanning electron Microscopy, Fourier transform infrared spectra, Brunauer-Emmett-Teller, energy dispersive X-ray, Zeta potential and particle size distribution values and AFM (Atomic force microscopy) techniques. Specially, our desired nanomaterial which has FA moieties on the surface of Tb@KCC-1-NH2-FA where interact with folate receptor (FR) which there is on the surface of the various cancer cells. For this purpose, fluorescence microscopy images were used to prove the uptake of FA based nanomaterial with FR-positive MDA breast cancer and HT 29 colon cancer cells. Also HEK 293 normal cells as FR-negative cells verified the specificity of our desired nanomaterial toward the FR-positive cells. The cytotoxicity survey of Tb@KCC-1-NH2 -FA was examined by MTT assays against MDA breast cancer, HT 29 colon cancer and HEK 293 Normal cell lines which confirmed their biocompatible nature with any significant cytotoxic effects even for concentration higher than 900 µg/mL which could be used as a non-toxic catalyst or carrier in biological ambient. Hence, Tb@KCC-1-NH2 -FA were synthesized using green and hydrothermal method; the process was simple with good productivity and desired nanocomposite was non-toxic.