Delivery of disulfiram into breast cancer cells using folate-receptor-targeted PLGA-PEG nanoparticles: in vitro and in vivo investigations

Background

A folate-receptor-targeted poly (lactide-co-Glycolide) (PLGA)-Polyethylene glycol (PEG) nanoparticle is developed for encapsulation and delivery of disulfiram into breast cancer cells. After a comprehensive characterization of nanoparticles, cell cytotoxicity, apoptosis induction, cellular uptake and intracellular level of reactive oxygen species are analyzed. In vivo acute and chronic toxicity of nanoparticles and their efficacy on inhibition of breast cancer tumor growth is studied.

Results

The folate-receptor-targeted nanoparticles are internalized into the cells, induce reactive oxygen species formation, induce apoptosis and inhibit cell proliferation more efficiently compared to the untargeted nanoparticles. The acute and toxicity test show the maximum dose of disulfiram equivalent of nanoparticles for intra-venous injection is 6 mg/kg while show significant decrease in the breast cancer tumor growth rate.

Conclusion

It is believed that the developed formulation could be used as a potential vehicle for successful delivery of disulfiram, an old and inexpensive drug, into breast cancer cells and other solid tumors.Graphical abstract

The basis for folinic acid treatment in neuro-psychiatric disorders

Multiple factors such as genetic and extraneous causes (drugs, toxins, adverse psychological events) contribute to neuro-psychiatric conditions. In a subgroup of these disorders, systemic folate deficiency has been associated with macrocytic anemia and neuropsychiatric phenotypes. In some of these, despite normal systemic levels, folate transport to the brain is impaired in the so-called cerebral folate deficiency (CFD) syndromes presenting as developmental and psychiatric disorders. These include infantile-onset CFD syndrome, infantile autism with or without neurologic deficits, a spastic-ataxic syndrome and intractable epilepsy in young children expanding to refractory schizophrenia in adolescents, and finally treatment-resistant major depression in adults. Folate receptor alpha (FRα) autoimmunity with low CSF N(5)-methyl-tetrahydrofolate (MTHF) underlies most CFD syndromes, whereas FRα gene abnormalities and mitochondrial gene defects are rarely found. The age at which FRα antibodies of the blocking type emerge, determines the clinical phenotype. Infantile CFD syndrome and autism with neurological deficits tend to be characterized by elevated FRα antibody titers and low CSF MTHF. In contrast, in infantile autism and intractable schizophrenia, abnormal behavioral signs and symptoms may wax and wane with fluctuating FRα antibody titers over time accompanied by cycling changes in CSF folate, tetrahydrobiopterin (BH4) and neurotransmitter metabolites ranging between low and normal levels. We propose a hypothetical model explaining the pathogenesis of schizophrenia. Based on findings from clinical, genetic, spinal fluid and MRI spectroscopic studies, we discuss the neurochemical changes associated with these disorders, metabolic and regulatory pathways, synthesis and catabolism of neurotransmitters, and the impact of oxidative stress on the pathogenesis of these conditions. A diagnostic algorithm and therapeutic regimens using high dose folinic acid, corticosteroids and milk-free diet is presented which has proven to be beneficial in providing adequate folate to the brain and decreasing the FRα autoantibody titer in those positive for the antibody.

Label-free femtomolar cancer biomarker detection in human serum using graphene-coated surface plasmon resonance chips

Sensitive and selective detection of cancer biomarkers is vital for the successful diagnosis of early stage cancer and follow-up treatment. Surface Plasmon Resonance (SPR) in combination with different amplification strategies is one of the analytical approaches allowing the screening of protein biomarkers in serum. Here we describe the development of a point-of-care sensor for the detection of folic acid protein (FAP) using graphene-based SPR chips. The exceptional properties of CVD graphene were exploited to construct a highly sensitive and selective SPR chip for folate biomarker sensing in serum. The specific recognition of FAP is based on the interaction between folic acid receptors integrated through π-stacking on the graphene coated SPR chip and the FAP analyte in serum. A simple post-adsorption of human serum:bovine serum albumin (HS:BSA) mixtures onto the folic acid modified sensor resulted in a highly anti-fouling interface, while keeping the sensing capabilities for folate biomarkers. This sensor allowed femtomolar (fM) detection of FAP, a detection limit well adapted and promising for quantitative clinical analysis.

Targeted delivery of 5-fluorouracil to cholangiocarcinoma cells using folic acid as a targeting agent

There are limits to the standard treatment for cholangiocarcinoma (CCA) including drug resistance and side effects. The objective of this study was to develop a new technique for carrying drugs by conjugation with gold nanoparticles and using folic acid as a targeting agent in order to increase drug sensitivity. Gold nanoparticles (AuNPs) were functionalized with 5-fluorouracil (5FU) and folic acid (FA) using polyethylene glycol (PEG) shell as a linker (AuNPs-PEG-5FU-FA). Its cytotoxicity was tested in CCA cell lines (M139 and M213) which express folic acid receptor (FA receptor). The results showed that AuNPs-PEG-5FU-FA increased the cytotoxic effects in the M139 and M213 cells by 4.76% and 7.95%, respectively compared to those treated with free 5FU+FA. It is found that the cytotoxicity of the AuNPs-PEG-5FU-FA correlates with FA receptor expression suggested the use of FA as a targeted therapy. The mechanism of cytotoxicity was mediated via mitochondrial apoptotic pathway as determined by apoptosis array. In conclusion, our findings shed some light on the use of gold nanoparticles for conjugation with potential compounds and FA as targeted therapy which contribute to the improvement of anti-cancer drug efficacy. In vivo study should be warranted for its effectiveness of stability, biosafety and side effect reduction.

Baicalin loaded in folate-PEG modified liposomes for enhanced stability and tumor targeting

Bioavailability of baicalin (BAI), an example of traditional Chinese medicine, has been modified by loading into liposome. Several liposome systems of different composition i.e., lipid/cholesterol (L), long-circulating stealth liposome (L-PEG) and folate receptor (FR)-targeted liposome (L-FA) have been used as the drug carrier for BAI. The obtained liposomes were around 80 nm in diameter with proper zeta potentials about -25 mV and sufficient physical stability in 3 months. The entrapment efficiency and loading efficiency of BAI in the liposomes were 41.0-46.4% and 8.8-10.0%, respectively. The morphology details of BAI lipsosome systems i.e., formation of small unilamellar vesicles, have been determined by cryogenic transmission electron microscopy (cryo-TEM) and small angle X-ray scattering (SAXS). In vitro cytotoxicity of BAI liposomes against HeLa cells was evaluated by MTT assay. BAI loaded FR-targeted liposomes showed higher cytotoxicity and cellular uptake compared with non-targeted liposomes. The results suggested that L-FA-BAI could enhance anti-tumor efficiency and should be an effective FR-targeted carrier system for BAI delivery.

Assessment of the specificity of a new folate-targeted photosensitizer for peritoneal metastasis of epithelial ovarian cancer to enable intraperitoneal photodynamic therapy. A preclinical study

BACKGROUND

Ovarian cancer's prognosis remains dire after primary therapy. Recurrence rate is disappointingly high as 60% of women with epithelial ovarian cancer considered in remission will develop recurrent disease within 5 years. Special attention to undetected peritoneal metastasis during surgery is necessary as they are the main predictive factors of recurrences. Folate Receptor α (FRα) shows promising prospects in targeting ovarian cancerous cells and intraperitoneal photodynamic therapy (PDT) could be a solution in addition to macroscopic cytoreductive surgery to treat peritoneal micrometastasis. The aim of this preclinical study is to assess the specificity of a folate-targeted photosensitizer for ovarian peritoneal micrometastasis.

METHODS

We used the NuTu-19 epithelial ovarian cancer cell line to induce peritoneal carcinomatosis in female Fischer 344 rats. Three groups of 6 rats were studied (Control (no photosensitizer)/Non-conjugated photosensitizer (Porph)/Folate-conjugated photosensitizer (Porph-s-FA)). Four hours after the administration of the photosensitizer, animals were sacrificed and intraperitoneal organs tissues were sampled. FRα tissue expression was evaluated by immunohistochemistry. Tissue incorporation of photosensitizers was assessed by confocal microscopy and tissue quantification.

RESULTS

FRα is overexpressed in tumor, ovary, and liver whereas, peritoneum, colon, small intestine, and kidney do not express it. Cytoplasmic red endocytosis vesicles observed by confocal microscopy are well correlated to FRα tissue expression. Photosensitizer tissue quantification shows a mean tumor-to-normal tissue ratio of 9.6.

CONCLUSION

We demonstrated that this new generation folate-targeted photosensitizer is specific of epithelial ovarian peritoneal metastasis and may allow the development of efficient and safe intraperitoneal PDT procedure.

Synthesis and evaluation of perfluorooctylbromide nanoparticles modified with a folate receptor for targeting ovarian cancer: in vitro and in vivo experiments

BACKGROUND

Epithelial ovarian cancer is the leading cause of death among gynecologic malignancies. However, detecting ovarian cancer at an early stage remains challenging. In this work, we aimed to synthesize a folate-receptor-targeting perfluorooctylbromide nanoparticle (FR-TPNP) as a targeted computed tomography (CT) contrast agent for the early detection of ovarian cancer.

METHODS

Perfluorooctylbromide (PFOB) was encapsulated in Poly (lactic-co-glycolic acid) (PLGA) by a two-step emulsion technique to construct the nanoparticles. Folate-poly (ethylene glycol)-carboxylic acid (Fol-PEG-COOH) was introduced to modify the surface of the nanoparticles through attachment to the PLGA. The effects of different volume ratios of PFOB to PLGA on the characteristics of the FR-TPNP emulsions were compared. The size distribution and potential of the FR-TPNPs were assessed with a laser particle size analyzer system. The in vitro targeting ability of the FR-TPNPs was observed with a confocal laser scanning microscope (CLSM), and the in vivo transportation of the FR-TPNPs was evaluated with CT.

RESULTS

The sizes of the FR-TPNP emulsion with different volume ratios varied from 302.67 ± 27.83 nm to 563.68 ± 47.29 nm, and the mean CT value ranged from 233 ± 20.59 HU to 587.66 ± 159.51 HU. Both the size and mean CT value increased with the volume ratio. The FR-TPNPs showed greater cell affinity and targeting efficiency to SKOV3 cells than the control group and folic acid interference group in vitro, as observed by CLSM. A significant CT enhancement of ovarian cancer xenografts in the targeted group of a nude mice model was observed 2 h post-injection; it increased to a peak at 12 h and had a duration of 48 h. The mean CT value of the tumor in the targeted group was considerably higher than those in the non-targeted and other groups 6 h post-injection.

CONCLUSION

The synthesized FR-TPNP emulsion was an effective CT contrast agent with highly efficient targeting ability and a long circulation time, thus representing a potential strategy for the earlier detection of ovarian cancer.

Synthesis and Evaluation of (99m)Tc-Labeled Folate-Tripeptide Conjugate as a Folate Receptor-Targeted Imaging Agent in a Tumor-Bearing Mouse Model

PURPOSE

The folate receptor (FR) is an attractive molecular target since it is overexpressed in a variety of human tumors. The purpose of the present study was to synthesize and evaluate the feasibility of a novel (99m)Tc-ECG-EDA (Glu-Cys-Gly-ethylenediamine)-folate as an FR-positive tumor imaging agent in a mouse tumor model.

MATERIALS AND METHODS

ECG-EDA-folate was synthesized using solid phase peptide synthesis (SPPS) and radiolabeled with (99m)Tc using tripeptide ECG as a chelator. FR-positive KB cells were inoculated in athymic nude mice. Following injection of (99m)Tc-ECG-EDA-folate, serial scintigraphy and micro-SPECT/CT imaging were performed at various time points with and without pre-administration of excess free folate. Mean count densities (MCD) for regions of interest drawn on KB tumors and major normal organs at each time point were measured, and uptake ratios of tumor to normal organs were calculated.

RESULTS

ECG-EDA-folate was labeled with (99m)Tc with high radiolabeling efficiency and stability (>96 %). FR-positive tumors were clearly visualized on both scintigraphy and micro-SPECT/CT images and the tumor uptake of (99m)Tc-ECG-EDA-folate was markedly suppressed with faint visualization of tumors by pre-administration of excess free folate on serial planar scintigraphy, indicating FR-specific binding of the agent. Furthermore, semiquantitative analysis of MCD data showed again that both tumor MCD and tumor-to-normal organ ratios decreased considerably by pre-administration of excess free folate, supporting FR-specific tumor uptake. Tumor-to-normal organ ratios approximately increased with time after injection until 4 h.

CONCLUSION

The present study demonstrated that (99m)Tc-ECG-EDA-folate can bind specifically to FR with clear visualization of FR-positive tumors in a mouse tumor model.

Folic-acid-conjugated pullulan/poly(DL-lactide-co-glycolide) graft copolymer nanoparticles for folate-receptor-mediated drug delivery

BACKGROUND

Nanoparticles have been extensively investigated for targeted delivery of anticancer drugs. Since the folate receptor is universally over-expressed on the tumor cell membrane, folic acid is often used to modify the fate of nanoparticles in biologicals.

METHODS

To fabricate targetable nanoparticles, folic acid was conjugated to a pullulan backbone and poly(DL-lactide-co-glycolide) (PLGA) (abbreviated as FAPuLG) was conjugated. KB cells and NIH3T3-cell-bearing mice were prepared to prove folate receptor targeting of FAPuLG nanoparticles.

RESULTS AND DISCUSSION

Nanoparticles of FAPuLG copolymer that self-assembled in water were small with diameters <200 nm. Doxorubicin (DOX) as a model drug was incorporated into the FAPuLG nanoparticles that were used to treat folate receptor over-expressing KB human carcinoma cells. Fluorescence microscopy revealed that DOX-incorporated FAPuLG nanoparticles induced strong red fluorescence in the KB cells in the absence of folic acid. However, fluorescence intensity was decreased by blocking folate receptors. Antitumor activity of FAPuLG nanoparticles against KB cells in vitro was also decreased by blocking folate receptors. In animal study using near-infrared dye-conjugated FAPuLG nanoparticles, fluorescence intensity was significantly higher at KB solid tumor than that of NIH3T3.

CONCLUSIONS

The results indicate that FAPuLG nanoparticles can target the folate receptor of tumor cells. FAPuLG nanoparticles are a promising candidate for active targeting of anticancer agents.

An investigation of antitumor efficiency of novel sustained and targeted 5-fluorouracil nanoparticles

Traditional chemotherapeutic drugs remain the major treatment for advanced colorectal cancer. However, due to the lack of tumor specificity these drug also destroy healthy tissue and organs, which has been the main reason for treatment failure and mortality. Folate-based drug delivery systems for improving nanoparticle endocytosis have been used to address these problems. Here, folic acid (FA) conjugated mPEG-b-P(CABCL-co-ACL) diblock copolymers were synthesized and characterized by TEM and NMR. Drug loaded nanoparticles were prepared using dialysis method and was obtained with a mean diameter of 45.2 nm with sustained in vitro release profile. In vitro cytotoxicity assay indicated that the cytotoxicity of folate modified nanoparticles were significantly increased compared to free drug and non-folate nanoparticles. In addition, results of hemolytic and histopathologic study suggested that the non-loaded nanoparticle (NL/NP) was non-toxic and biocompatible at the testing concentration. Moreover, in vivo results showed that FA/5-FU/NP effectively inhibited growth of HCT-8 cell-based xenograft tumors in BALB/c mice and revealed stronger antitumor efficacy than other treated groups. Thus, both in vitro and in vivo results exhibited that the folate conjugated mPEG-b-P(CABCL-co-ACL) copolymers have great potential to be used as sustainable and specific colon cancer targeting delivery system for anticancer agents.

Folinic acid treatment for schizophrenia associated with folate receptor autoantibodies

BACKGROUND

Auto-antibodies against folate receptor alpha (FRα) at the choroid plexus that block N(5)-methyltetrahydrofolate (MTHF) transfer to the brain were identified in catatonic schizophrenia. Acoustic hallucinations disappeared following folinic acid treatment. Folate transport to the CNS prevents homocysteine accumulation and delivers one-carbon units for methyl-transfer reactions and synthesis of purines. The guanosine derivative tetrahydrobiopterin acts as common co-factor for the enzymes producing dopamine, serotonin and nitric oxide.

METHODS

Our study selected patients with schizophrenia unresponsive to conventional treatment. Serum from these patients with normal plasma homocysteine, folate and vitamin B12 was tested for FR autoantibodies of the blocking type on serial samples each week. Spinal fluid was analyzed for MTHF and the metabolites of pterins, dopamine and serotonin. The clinical response to folinic acid treatment was evaluated.

RESULTS

Fifteen of 18 patients (83.3%) had positive serum FR auto-antibodies compared to only 1 in 30 controls (3.3%) (χ(2)=21.6; p<0.0001). FRα antibody titers in patients fluctuated over time varying between negative and high titers, modulating folate flux to the CNS, which explained low CSF folate values in 6 and normal values in 7 patients. The mean±SD for CSF MTHF was diminished compared to previously established controls (t-test: 3.90; p=0.0002). A positive linear correlation existed between CSF MTHF and biopterin levels. CSF dopamine and serotonin metabolites were low or in the lower normal range. Administration of folinic acid (0.3-1mg/kg/day) to 7 participating patients during at least six months resulted in clinical improvement.

CONCLUSION

Assessment of FR auto-antibodies in serum is recommended for schizophrenic patients. Clinical negative or positive symptoms are speculated to be influenced by the level and evolution of FRα antibody titers which determine folate flux to the brain with up- or down-regulation of brain folate intermediates linked to metabolic processes affecting homocysteine levels, synthesis of tetrahydrobiopterin and neurotransmitters. Folinic acid intervention appears to stabilize the disease process.

Development and pre-clinical evaluation of new 68Ga-NOTA-folate conjugates for PET imaging of folate receptor-positive tumors

In an attempt to develop new folate radiotracers with favorable biochemical properties for detecting folate receptor-positive cancers, we synthesized 68Ga-NOTA- and 68Ga-NOTAM-folate conjugates using a straightforward and a one-step simple reaction. Radiochemical yields were greater than 95% (decay-corrected) with total synthesis time of less than 20 min. Radiochemical purities were always greater than 98% without high-performance liquid chromatography (HPLC) purification. These synthetic approaches hold considerable promise as a rapid and simple method for 68Ga-folate conjugate preparation with high radiochemical yield in a short synthesis time. In vitro tests on the KB cell line showed that significant amounts of the radioconjugates were associated with cell fractions. Biodistribution studies in nude mice bearing human KB xenografts, demonstrated a significant tumor uptake and favorable biodistribution profile for 68Ga-NOTA-folate over the 68Ga-NOTAM-folate conjugate. The uptake in the tumors was blocked by excess injection of folic acid, suggesting a receptor-mediated process. These results demonstrate that the 68Ga-NOTA-folate conjugate may be useful as a molecular probe for detection and staging of folate receptor-positive cancers, such as ovarian cancer and their metastasis, as well as monitoring tumor response to treatment.

Novel serum-tolerant lipoplexes target the folate receptor efficiently

Gene transfer using non-viral vectors is a promising approach for the safe delivery of nucleic acid therapeutics. In this study, we investigate a lipid-based system for targeted gene delivery to malignant cells overexpressing the folate receptor (FR). Cationic liposomes were formulated with and without the targeting ligand folate conjugated to distearoylphosphatidyl ethanolamine polyethylene glycol 2000 (DSPE-PEG2000), the novel cytofectin 3β[N(N(1),N(1)-dimethlaminopropylsuccinamidoethane)-carbamoyl]cholesterol (SGO4), which contains a 13atom, 15Å spacer element, and the helper lipid, dioleoylphosphatidylethanolamine (DOPE). Physicochemical parameters of the liposomes and lipoplexes were obtained by zeta sizing, zeta potential measurement and cryo-TEM. DNA-binding and protection capabilities of liposomes were confirmed by gel retardation assays, EtBr intercalation and nuclease protection assays. The complexes were assessed in an in vitro system for their effect on cell viability using the MTT assay, and gene transfection activity using the luciferase assay in three cell lines; HEK293 (FR-negative), HeLa (FR(+)-positive), KB (FR(++)-positive). Low cytotoxicities were observed in all cell lines, while transgene activity promoted by folate-tagged lipoplexes in FR-positive lines was tenfold greater than that by untargeted constructs and cell entry by folate complexes was demonstrably by FR mediation. These liposome formulations have the design capacity for in vivo application and may therefore be promising candidates for further development.

Development and preclinical evaluation of new (124)I-folate conjugates for PET imaging of folate receptor-positive tumors

In an attempt to develop new folate radiotracers with favorable biochemical properties for detecting folate receptor-positive cancers, we have synthesized [(124)I]-SIB- and [(124)I]-SIP-folate conjugates using a straightforward and two-step simple reactions. Radiochemical yields for [(124)I]-SIB- and [(124)I]-SIP-folate conjugates were greater than 90 and 60% respectively, with total synthesis time of 30-40min. Radiochemical purities were always greater than 98% without HPLC purification. These synthetic approaches hold considerable promise as rapid and simple method for (124)I-folate conjugate preparation with high radiochemical yield in short synthesis time. In vitro tests on KB cell line showed that the significant amounts of the radioconjugates were associated with cell fractions. In vivo characterization in normal Balb/c mice revealed rapid blood clearance of these radioconjugates and favorable biodistribution profile for [(124)I]-SIP-folate conjugate over [(124)I]-SIB-folate conjugate. Biodistribution studies of [(124)I]-SIP-folate conjugate in nude mice bearing human KB cell line xenografts, demonstrated significant tumor uptake. The uptake in the tumors was blocked by excess injection of folic acid, suggesting a receptor-mediated process. These results demonstrate that [(124)I]-SIP-folate conjugate may be useful as a molecular probe for detecting and staging of folate receptor-positive cancers, such as ovarian cancer and their metastasis as well as monitoring tumor response to treatment.

LRP2 mediates folate uptake in the developing neural tube

The low-density lipoprotein (LDL) receptor-related protein 2 (LRP2) is a multifunctional cell-surface receptor expressed in the embryonic neuroepithelium. Loss of LRP2 in the developing murine central nervous system (CNS) causes impaired closure of the rostral neural tube at embryonic stage (E) 9.0. Similar neural tube defects (NTDs) have previously been attributed to impaired folate metabolism in mice. We therefore asked whether LRP2 might be required for the delivery of folate to neuroepithelial cells during neurulation. Uptake assays in whole-embryo cultures showed that LRP2-deficient neuroepithelial cells are unable to mediate the uptake of folate bound to soluble folate receptor 1 (sFOLR1). Consequently, folate concentrations are significantly reduced in Lrp2(-/-) embryos compared with control littermates. Moreover, the folic-acid-dependent gene Alx3 is significantly downregulated in Lrp2 mutants. In conclusion, we show that LRP2 is essential for cellular folate uptake in the developing neural tube, a crucial step for proper neural tube closure.

Targeted uptake of folic acid-functionalized iron oxide nanoparticles by ovarian cancer cells in the presence but not in the absence of serum

Targeted delivery of nanoparticles to cells or tissues of interest is arguably the "holy grail" of nanomedicine. Using primary human macrophages and ovarian cancer cells, we evaluated the biocompatibility and specific targeting of folic acid (FA)-conjugated iron oxide nanoparticles with organic [poly(ethylene glycol), PEG] or inorganic (SiO2) intermediate surface coatings. Reduction of folate receptor-α expression using specific siRNA resulted in a significant decrease in cellular uptake of the SiO2-coated nanoparticles, but did not affect uptake of PEG-coated nanoparticles. Notably, specific (i.e. FA-dependent) uptake was observed only in the presence of serum proteins. The strategy presented here for receptor-mediated uptake of nanoparticles with pre-defined surface chemistry may enable targeting of nanoparticles for therapeutic and imaging applications. From the clinical editor: In this study the receptor specific uptake of folic acid-functionalized iron oxide nanoparticles was determined in ovarian cancer cells. It was found that the presence of serum proteins is an absolute requirement for the uptake of these nanoparticles. The described strategy for receptor-mediated uptake of nanoparticles with pre-defined surface chemistry may enable a better targeting of nanoparticles for additional therapeutic and imaging applications.

Mutation at the folate receptor 4 locus modulates gene expression profiles in the mouse uterus in response to periconceptional folate supplementation

Periconceptional supplementation of folic acid to the diet of women is considered a great success for a public health intervention. Higher folate status, either by supplementation, or via the mandatory fortification of grain products in the United States, has led to significant reduction in the incidence of neural tube defects. Besides birth defects, folate deficiency has been linked to a variety of morbidities, most notably to increased risk for cancer. However, recent evidence suggests that excess folate may be detrimental - for birth defect incidence or in the progression of cancer. How folate mediates beneficial or detrimental effects is not well understood. It is also unknown what molecular responses are elicited in women taking folate supplements, and thus experience a bolus of folate on top of the status achieved by fortification. To characterize the response to a periconceptional regimen of supplementation with folinic acid, we performed gene expression profiling experiments on uterus tissue of pregnant mice with either wildtype alleles or targeted disruption at the folate receptor 4 locus. We observed that, depending on the genetic background, folinic acid supplementation affects expression of genes that contribute to lipid metabolism, protein synthesis, mitochondrial function, cell cycle, and cell activation. The extent of the response is strongly modulated by the genetic background. Finally, we provide evidence that folinic acid supplementation in the mutant paradigm affects histone methylation status, a potential mechanism of gene regulation in this model.

Targeted fluoromagnetic nanoparticles for imaging of breast cancer mcf-7 cells

PURPOSE

To achieve simultaneous imaging and therapy potentials, targeted fluoromagnetic nanoparticles were synthesized and examined in human breast cancer MCF-7 cells.

METHODS

Fe3O4 nanoparticles (NPs) were synthesized through thermal decomposition of Fe(acac)3. Then, magnetic nanoparticles (MNPs) modified by dopamine-poly ethylene glycol (PEG)-NH2; finally, half equivalent fluorescein isothiocyanate (FITC) and half equivalent folic acid were conjugated to one equivalent of it. The presence of Fe3O4-DPA-PEG-FA/FITC in the folate receptor (FR) positive MCF-7 cells was determined via fluorescent microscopy to monitor the cellular interaction of MNPs.

RESULTS

FT-IR spectra of final compound confirmed existence of fluorescein on folic acid grafted MNPs. The Fe3O4-DPA-PEG-FA/FITC NPs, which displayed a size rang about 30-35 nm using scanning electron microscopy (SEM) and transmission electron microscopy (TEM), were able to actively recognize the FR-positive MCF-7 cells, but not the FR-negative A549 cells.

CONCLUSION

The uniform nano-sized Fe3O4-DPA-PEG-FA/FITC NPs displayed great potential as theranostics and can be used for targeted imaging of various tumors that overexpress FR.

Transforming a Targeted Porphyrin Theranostic Agent into a PET Imaging Probe for Cancer

Porphyrin based photosensitizers are useful agents for photodynamic therapy (PDT) and fluorescence imaging of cancer. Porphyrins are also excellent metal chelators forming highly stable metallo-complexes making them efficient delivery vehicles for radioisotopes. Here we investigated the possibility of incorporating (64)Cu into a porphyrin-peptide-folate (PPF) probe developed previously as folate receptor (FR) targeted fluorescent/PDT agent, and evaluated the potential of turning the resulting (64)Cu-PPF into a positron emission tomography (PET) probe for cancer imaging. Noninvasive PET imaging followed by radioassay evaluated the tumor accumulation, pharmacokinetics and biodistribution of (64)Cu-PPF. (64)Cu-PPF uptake in FR-positive tumors was visible on small-animal PET images with high tumor-to-muscle ratio (8.88 ± 3.60) observed after 24 h. Competitive blocking studies confirmed the FR-mediated tracer uptake by the tumor. The ease of efficient (64)Cu-radiolabeling of PPF while retaining its favorable biodistribution, pharmacokinetics and selective tumor uptake, provides a robust strategy to transform tumor-targeted porphyrin-based photosensitizers into PET imaging probes.