5-Fluorouracil nano-delivery systems as a cutting-edge for cancer therapy

5-Fluorouracil Loaded Prebiotic-Probiotic Liposomes Modulating Gut Microbiota for Improving Colorectal Cancer Chemotherapy

The gut microbiota exerts inhibitory effects on the occurrence and progression of colorectal cancer (CRC) through various mechanisms. Compared to traditional microbiota regulation methods, prebiotics and probiotics demonstrate significant advantages in terms of safety and patient adaptability. Their synergy not only improves the intestinal environment but also enhances the host's anti-tumor immune response. 5-Fluorouracil (5-FU) is a first-line chemotherapy drug that has a short half-life and low bioavailability. However, if administered in an untargeted manner, 5-FU also causes adverse reactions. Liposomes can improve the pharmacokinetic profile of drugs and provide targeted delivery to the tumor site, thereby reducing side effects. In this work, a 5-FU-loaded liposome is modified with the prebiotic xylan derivative Sxy and the probiotic Akkermansia muciniphila active phospholipid homolog 1,2-dipalmitoylphosphatidy-lethanolamine (DPPE) to construct FLSK. The latter effectively prolongs the intestinal transport and release of 5-FU, maintaining high drug concentrations at the tumor site. FLSK is found to inhibit tumor growth and significantly extends the survival period of mice. In addition, FLSK promotes anti-tumor immunity and regulation of the gut microbiota. Combining the merits of prebiotics and probiotics, FLSK provides a potential strategy for integrating chemotherapy with gut microbiota regulation therapy for the treatment of CRC.

A Coarse-Grained Molecular Dynamics Perspective on the Release of 5-Fluorouracil from Liposomes

Liposomes, small bilayer phospholipid-containing vesicles, are frequently used to ensure slow drug release for a prolonged and improved therapeutic effect. Nevertheless, current findings on the membrane affinity and permeability of the anticancer agent 5-fluorouracil (5-FU) are confounding, which leads to a lack of a clear understanding of how lipid composition impacts the distribution of 5-FU within liposomal structures and its delivery. In the current work, we report a comprehensive coarse-grained molecular dynamics (CGMD) investigation on the influence of cholesterol (CHOL) and the cationic lipid 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP) on the partitioning of 5-FU in 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) double-bilayer systems, as well as its in vitro release from liposomes with identical lipid compositions. Our results show that 5-FU tends to accumulate at the water-lipid interface, in the vicinity of polar headgroups, without partitioning in the hydrophobic tail region. At the same time, the presence of CHOL proportionally increases the distribution of this drug in the interbilayer aqueous space, decreasing the drug's affinity toward the membrane polar head region, while DOTAP has only a slight effect on drug distribution. Thus, it is expected that 5-FU will be released slower from CHOL-containing DPPC liposomes but not DOTAP-containing vesicles. However, in vitro release studies showed that the release kinetics of 5-FU from DPPC vesicles is not influenced by the presence of CHOL and that the incorporation of 10 mol % DOTAP leads to the best release profile for 5-FU, highlighting the complexity of nanocarrier drug release kinetics. We hypothesize that the initial rapid release seen in dialysis experiments is not related to drug membrane permeability but rather to 5-FU adsorbed on the outer surface of liposomes.

Evaluation of the Clinical Safety of the Low-Cost Warburg Therapy for the Treatment of Patients With Advanced Cancers

BACKGROUND

Rising cancer care costs are becoming cost prohibitive for lower income people worldwide. We developed the Warburg protocol as a low-cost option for the treatment of cancer that was inspired. It was developed to exploit an Achilles heel which is a hallmark of cancer cells; the metabolic requirement for higher levels of glucose than normal cells.

OBJECTIVE

The purpose of this report is to assess the clinical safety and affordability of the Warburg therapy as an option for patients with advanced cancers.

METHODS

Between 2021 and 2023, 251 patients with advanced cancers received a total of 8542 treatments with the Warburg therapy. To restrict the supply of blood glucose to cancerous tumors, regular human insulin was administered (IV) sufficient to reduce blood glucose concentrations to hypoglycemic levels for 40-60 min. Subroutine doses of fluorouracil and cyclophosphamide were administered intravenously during this hypoglycemic period. Food or intravenous glucose was given as needed to return blood glucose to euglycemic levels after treatment. Patient symptoms, status, vitals, blood glucose, and hypoglycemic symptoms were monitored throughout treatment. Various blood parameters were measured before and after patients' course of treatment.

RESULTS

There were no irreversible adverse reactions in advanced tumor patients of different ages and different cancer types after treatment. There was no significant fluctuation in blood glucose levels in diabetic and non-diabetic patients after treatment, and the weight, vital index and blood biochemical index of patients before and after multiple treatments exhibited little variation.

CONCLUSION

Warburg therapy for the treatment of advanced tumors is clinically feasible, and safe for multiple treatments. It is inexpensive and widely applicable to different patient groups.

Advances in the delivery of anticancer drugs by nanoparticles and chitosan-based nanoparticles

Cancer is the leading cause of death globally, and conventional treatments have limited efficacy with severe side effects. The use of nanotechnology has the potential to reduce the side effects of drugs by creating efficient and controlled anticancer drug delivery systems. Nanoparticles (NPs) used as drug carriers offer several advantages, including enhanced drug protection, biodistribution, selectivity and, pharmacokinetics. Therefore, this review is devoted to various organic (lipid, polymeric) as well as inorganic nanoparticles based on different building units and providing a wide range of potent anticancer drug delivery systems. Within these nanoparticulate systems, chitosan (CS)-based NPs are discussed with particular emphasis due to the unique properties of CS and its derivatives including non-toxicity, biodegradability, mucoadhesivity, and tunable physico-chemical as well as biological properties allowing their alteration to specifically target cancer cells. In the context of streamlining the nanoparticulate drug delivery systems (DDS), innovative nanoplatform-based cancer therapy pathways involving passive and active targeting as well as stimuli-responsive DDS enhancing overall orthogonality of developed NP-DDS towards the target are included. The most up-to-date information on delivering anti-cancer drugs using modern dosage forms based on various nanoparticulate systems and, specifically, CSNPs, are summarised and evaluated concerning their benefits, limitations, and advanced applications.

Implications of RNA pseudouridylation for cancer biology and therapeutics: a narrative review

BACKGROUND

Pseudouridine (Ψ), a C5-glycoside isomer of uridine, stands as one of the most prevalent RNA modifications in all RNA types. Distinguishing from the C-N bond linking uridine to ribose, the link between Ψ and ribose is a C-C bond, endowing Ψ modified RNA distinct properties and functions in various biological processes. The conversion of uridine to Ψ is governed by pseudouridine synthases (PUSs). RNA pseudouridylation is implicated in cancer biology and therapeutics.

OBJECTIVES

In this review, we will summarize the methods for detecting Ψ, the process of Ψ generation, the impact of Ψ modification on RNA metabolism and gene expression, the roles of dysregulated Ψ and pseudouridine synthases in cancers, and the underlying mechanism.

METHODS

We conducted a comprehensive search of PubMed from its inception through February 2024. The search terms included "pseudouridine"; "pseudouridine synthase"; "PUS"; "dyskerin"; "cancer"; "tumor"; "carcinoma"; "malignancy"; "tumorigenesis"; "biomarker"; "prognosis" and "therapy". We included studies published in peer-reviewed journals that focused on Ψ detection, specific mechanisms involving Ψ and PUSs, and prognosis in cancer patients with high Ψ expression. We excluded studies lacking sufficient methodological details or appropriate controls.

RESULTS

Ψ has been recognized as a significant biomarker in cancer diagnosis and prognosis. Abnormal Ψ modifications mediated by various PUSs result in dysregulated RNA metabolism and impaired RNA function, promoting the development of various cancers. Overexpression of PUSs is common in cancer cells and predicts poor prognosis. PUSs inhibition arrests cell proliferation and enhances apoptosis in cancer cells, suggesting PUS-targeting cancer therapy may be a potential strategy in cancer treatment.

DISCUSSION

High Ψ levels in serum, urine, and saliva may suggest cancer, but do not specify the type, requiring additional lab markers and imaging for accurate diagnosis. Standardized detection methods are also crucial for reliable results. PUSs are linked to cancer, but more researches are needed to understand their mechanisms in different cancers. Anticancer treatments targeting PUSs are still under developed.

Review of METTL3 in colorectal cancer: From mechanisms to the therapeutic potential

N6-methyladenosine (m6A), the most abundant modification in mRNAs, affects the fate of the modified RNAs at the post-transcriptional level and participants in various biological and pathological processes. Increasing evidence shows that m6A modification plays a role in the progression of many malignancies, including colorectal cancer (CRC). As the only catalytic subunit in methyltransferase complex, methyltransferase-like 3 (METTL3) is essential to the performance of m6A modification. It has been found that METTL3 is associated with the prognosis of CRC and significantly influences various aspects of CRC, such as cell proliferation, invasion, migration, metastasis, metabolism, tumor microcirculation, tumor microenvironment, and drug resistance. The relationship between METTL3 and gut-microbiota is also involved into the progression of CRC. Furthermore, METTL3 might be a viable target for CRC treatment to prolong survival. In this review, we comprehensively summarize the function of METTL3 in CRC and the underlying molecular mechanisms. We aim to deepen understanding and offer new ideas for diagnostic biomarkers and therapeutic targets for colorectal cancer.

Delivery of 5-fluorouracil for cancer therapy using aptamer-based nonlinear hybridization chain reaction

5-Fluorouracil (5-FU) is a conventional nucleotide analogue used for cancer treatment. However, its clinical application faces challenges such as low stability and non-specific toxicity. With the remarkable advancements in DNA nanotechnology, DNA-based self-assembled nanocarriers have emerged as powerful tools for delivering nucleotide drugs. In this study, we have designed a non-linear hybrid chain reaction involving a fuel strand with AS1411 aptamer sequence to construct a dendritic structure capable of carrying 5-FU. This structure specifically targets cancer cells with overexpressed nucleolin on their surface, allowing the 5-FU to exert its anticancer effects and achieve therapeutic outcomes. Furthermore, we have also investigated the mechanistic action of this drug delivery system, aiming to establish a novel therapeutic platform for 5-FU treatment.

Production of 5-fluorouracil-loaded PLGA nanoparticles with toroidal microfluidic system and optimization of process variables by design of experiments

In recent decades, microfluidics has presented new opportunities for the production of nanoparticles (NPs). However, to achieve rapid clinical translation, the production of PLGA NPs in a single microfluidic channel for both the pharmaceutical research and industry without the need for scaling is still limited. The aim of this study was to accomplish the production of reproducible and stable 5-FU loaded Poly(lactic-co-glycolic acid) (PLGA) NPs, using an innovative toroidal microfluidic system, for cancer therapy. The toroidal microfluidic system enabled the production of spherical NPs ranging from 100 to 150 nm by adjusting both the TFR within the range of 5-15 mL/min and FRR between 1:3 and 1:7. A systematic assessment of critical process variables (total flow rate; TFR, flow rate ratio; FRR) for the production of PLGA NPs was conducted using Design of Experiment (DoE). The NPs, which exhibit a uniform size distribution, remained stable even after centrifugation and storage for 3 months at 4 °C. The encapsulation efficiency of drug and the concentration of NPs were not affected by changing process parameters. The effective 5-FU encapsulation into NPs resulted in a controlled in vitro drug release. Due to the controlled release profile of the 5-FU loaded PLGA NPs, the formulation was a promising candidate for mitigating the toxic side effects of free 5-FU and improving cancer treatment. In conclusion, toroidal microfluidic system enables high-volume production of stable PLGA NPs, both with and without 5-FU.

The smart nanocarrier containing zein/starch co-biopolymers enhanced by graphitic carbon nitride; exploring opportunities in brain cancer treatment

In this investigation, we present an innovative pH-responsive nanocomposite designed to address challenges associated with using 5-Fluorouracil (5-FU) in cancer therapy. The nanocomposite containing zein (Z), starch (S), and graphitic carbon nitride (g-C3N4) macromolecules is synthesized by a water-in-oil-in-water (W/O/W) double emulsion technique, serving as a carrier for 5-FU. The S/Z hydrogel matrix's entrapment and loading efficiency are greatly improved by adding g-C3N4 nanosheets, reaching noteworthy values of 45.25 % and 86.5 %, respectively, for drug loading efficiency and entrapment efficiency. Characterization through FTIR and XRD validates the successful loading of 5-FU, elucidating the chemical bonding within the nanocomposite and crystalline characteristics. Structural analysis using FESEM, along with DLS and zeta potential measurements, reveals an average nanocomposite size of 193.48 nm, indicating a controlled structure, and a zeta potential of -42.32 mV, signifying a negatively charged surface. Studies on the in vitro release of drugs reveal that 5-FU is delivered more effectively and sustainably in acidic environments than in physiological circumstances. This highlights the fact that the created nanocarrier is pH-sensitive. Modeling release kinetics involves finding the right mathematical conditions representing underlying physicochemical processes. Employing curve-fitting techniques, predominant release mechanisms are identified, and optimal-fitting kinetic models are determined. The Baker kinetic model performed best at pH 7.4, indicating that the leading cause of the drug release was polymer swelling. In contrast, the Higuchi model was most accurate for drug release at pH 5.4, illuminating the diffusion and dissolution mechanisms involved in diffusion. To be more precise, the mechanism of release at pH 7.4 and 5.4 was anomalous transport (dissolution-controlled), according to the Korsmeyer-Peppas mathematical model. The pH-dependent swelling and degradation behavior of S/Z/g-C3N4@5-FU nanocomposite showed higher swelling and faster degradation in acidic environments compared to neutral conditions. Crucially, outcomes from the MTT test affirm the significant cytotoxicity of the 5-FU-loaded nanocomposite against U-87 MG brain cancer cells, while simultaneously indicating non-toxicity towards L929 fibroblast cells. These cumulative findings underscore the potential of the engineered S/Z/g-C3N4@5-FU as a productive and targeted therapeutic approach for cancer cells.

Preparation of Microsponge Drug Delivery System (MSDDS) Followed by a Scale-Up Approach

In 1987, Won invented the solid-phase porous microsphere (MS), which stores bioactive compounds in many interconnected voids. Spherical particles (5-300 μm), MS, may form clusters of smaller spheres, resulting in many benefits. The current investigation focussed on gel-encased formulation, which can be suitable for dermal usage. First, quasi-emulsion (w/o/w) solvent evaporation was used to prepare 5-fluorouracil (5 FU) MS particles. The final product was characterized (SEM shows porous structure, FTIR and DSC showed drug compatibility with excipients, and gel formulation is shear-thinning) and further scaled up using the 8-fold method. Furthermore, CCD (Central Composite Design) was implemented to obtain the optimized results. After optimizing the conditions, including the polymer (600 mg, ethyl cellulose (EC), eudragit RS 100 (ERS)), stirring speed (1197 rpm), and surfactant concentration (2% w/v), we achieved the following results: optimal yield (63%), mean particle size (152 µm), drug entrapment efficiency (76%), and cumulative drug release (74.24% within 8 h). These findings are promising for industrial applications and align with the objectives outlined in UN Sustainable Development Goals 3, 9, and 17, as well as the goals of the G20 initiative.

MiR-22-3p Inhibits 5-Fluorouracil Resistance in Cholangiocarcinoma Cells Through PTEN/PI3K/AKT Axis

Cholangiocarcinoma (CCA) is a prevalent and highly lethal form of cancer globally. Although microRNAs (miRNAs) have been implicated in the advancement of CCA, their potential influence on 5-fluorouracil (5-Fu) resistance in CCA remains to be fully elucidated. Here, in this study, we investigated the impact of miR-22-3p on CCA resistance. Our investigation involved bioinformatics analysis, which revealed an association between miR-22-3p and the progression, diagnosis, and patient survival of CCA. Furthermore, we validated a notable downregulation of miR-22-3p expression in CCA cell lines. Elevated levels of miR-22-3p inhibit the activity and proliferation of 5-Fu-resistant CCA cell lines. In addition, we confirmed that phosphatase and tensin homolog deleted on chromosome 10 (PTEN) is a target gene of miR-22-3p, and its expression correlates with the survival of CCA patients. Reduced PTEN expression enhances apoptosis in 5-Fu-resistant CCA cells. Meanwhile, we verified the existence of the miR-22-3p/PTEN/phosphatidylinositol-3 kinase (PI3K)/Protein kinase B (AKT) regulatory networks in CCA, influencing the sensitivity of CCA cells to 5-Fu. In conclusion, our findings suggest that miR-22-3p acts as a tumor suppressor. Its overexpression inhibits the PTEN/PI3K/AKT axis, promoting cell apoptosis and enhancing CCA sensitivity to 5-Fu.

Electrochemical Characterization of the Encapsulation and Release of 5-Fluorouracil in Nanocarriers Formed from Soy Lecithin Vesicles

5-Fluorouracil (5-FU) is an antineoplastic agent known for its low bioavailability and limited cellular penetration, often resulting in adverse effects on healthy cells. Thus, finding vehicles that enhance bioavailability, enable controlled release, and mitigate adverse effects is crucial. The study focuses on encapsulating 5-FU within soy lecithin vesicles (SLVs) and assessing its impact on the carrier's properties and functionality. Results show that incorporating 5-FU does not affect SLVs' size or polydispersity, even postlyophilization. Liberation of 5-FU from SLVs requires system disruption rather than spontaneous release, with an encapsulation efficiency of approximately 43% determined using Square Wave Voltammetry. Cytotoxicity assays on colorectal cancer cells reveal SLV-based delivery's significant efficacy, surpassing free drug solution effects with 45% cell viability after 72 h vs 73% viability. The research addresses 5-FU's limited bioavailability by creating a biocompatible nanocarrier for efficient drug delivery, highlighting SLVs as promising for targeted cancer therapy due to sustained antiproliferative effects and improved cellular uptake. The study underscores the importance of tailored drug delivery systems in enhancing therapeutic outcomes and suggests SLV/5-FU formulations as a potential advancement in cancer treatment strategies.

Parabacteroides distasonis-Derived Outer Membrane Vesicles Enhance Antitumor Immunity Against Colon Tumors by Modulating CXCL10 and CD8+ T Cells

Purpose

Given the potent immunostimulatory effects of bacterial outer membrane vesicles (OMVs) and the significant anti-colon tumor properties of Parabacteroides distasonis (Pd), this study aimed to elucidate the role and potential mechanisms of Pd-derived OMVs (Pd-OMVs) against colon cancer.

Methods

This study isolated and purified Pd-OMVs from Pd cultures and assessed their characteristics. The effects of Pd-OMVs on CT26 cell uptake, proliferation, and invasion were investigated in vitro. In vivo, a CT26 colon tumor model was used to investigate the anti-colon tumor effects and underlying mechanisms of Pd-OMVs. Finally, we evaluated the biosafety of Pd-OMVs.

Results

Purified Pd-OMVs had a uniform cup-shaped structure with an average size of 165.5 nm and a zeta potential of approximately -9.56 mV, and their proteins were associated with pathways related to immunity and apoptosis. In vitro experiments demonstrated that CT26 cells internalized the Pd-OMVs, resulting in a significant decrease in their proliferation and invasion abilities. Further in vivo studies confirmed the accumulation of Pd-OMVs in tumor tissues, which significantly inhibited the growth of colon tumors. Mechanistically, Pd-OMVs increased the expression of CXCL10, promoting infiltration of CD8+ T cells into tumor tissues and expression of pro-inflammatory factors TNF-α, IL-1β, and IL-6. Notably, Pd-OMVs demonstrated a high level of biosafety.

Conclusion

This paper elucidates that Pd-OMVs can exert significant anti-colon tumor effects by upregulating the expression of the chemokine CXCL10, thereby increasing the infiltration of CD8+ T cells into tumors and enhancing antitumor immune responses. This suggests that Pd-OMVs may be developed as a novel nanoscale potent immunostimulant with great potential for application in tumor immunotherapy. As well as developed as a novel nano-delivery carrier for combination with other antitumor drugs.

Identification and validation of a novel risk model based on cuproptosis‑associated m6A for head and neck squamous cell carcinoma

BACKGROUND

Head and neck squamous cell carcinoma (HNSCC) is a prevalent cancer with a poor survival rate due to anatomical limitations of the head and a lack of reliable biomarkers. Cuproptosis represents a novel cellular regulated death pathway, and N6-methyladenosine (m6A) is the most common internal RNA modification in mRNA. They are intricately connected to tumor formation, progression, and prognosis. This study aimed to construct a risk model for HNSCC using a set of mRNAs associated with m6A regulators and cuproptosis genes (mcrmRNA).

METHODS

RNA-seq and clinical data of HNSCC patients from The Cancer Genome Atlas (TCGA) database were analyzed to develop a risk model through the least absolute shrinkage and selection operator (LASSO) analysis. Survival analysis and receiver operating characteristic (ROC) analysis were performed for the high- and low-risk groups. Additionally, the model was validated using the GSE41613 dataset from the Gene Expression Omnibus (GEO) database. GSEA and CIBERSORT were applied to investigate the immune microenvironment of HNSCC.

RESULTS

A risk model consisting of 32 mcrmRNA was developed using the LASSO analysis. The risk score of patients was confirmed to be an independent prognostic indicator by multivariate Cox analysis. The high-risk group exhibited a higher tumor mutation burden. Additionally, CIBERSORT analysis indicated varying levels of immune cell infiltration between the two groups. Significant disparities in drug sensitivity to common medications were also observed. Enrichment analysis further unveiled significant differences in metabolic pathways and RNA processing between the two groups.

CONCLUSIONS

Our risk model can predict outcomes for HNSCC patients and offers valuable insights for personalized therapeutic approaches.

Revolutionizing Cancer Treatment: Biopolymer-Based Aerogels as Smart Platforms for Targeted Drug Delivery

Cancer stands as a leading cause of global mortality, with chemotherapy being a pivotal treatment approach, either alone or in conjunction with other therapies. The primary goal of these therapies is to inhibit the growth of cancer cells specifically, while minimizing harm to healthy dividing cells. Conventional treatments, often causing patient discomfort due to side effects, have led researchers to explore innovative, targeted cancer cell therapies. Thus, biopolymer-based aerogels emerge as innovative platforms, showcasing unique properties that respond intelligently to diverse stimuli. This responsiveness enables precise control over the release of anticancer drugs, enhancing therapeutic outcomes. The significance of these aerogels lies in their ability to offer targeted drug delivery with increased efficacy, biocompatibility, and a high drug payload. In this comprehensive review, the author discuss the role of biopolymer-based aerogels as an emerging functionalized platforms in anticancer drug delivery. The review addresses the unique properties of biopolymer-based aerogels showing their smart behavior in responding to different stimuli including temperature, pH, magnetic and redox potential to control anticancer drug release. Finally, the review discusses the application of different biopolymer-based aerogel in delivering different anticancer drugs and also discusses the potential of these platforms in gene delivery applications.

Enhanced In Vitro Antiviral Activity of Ivermectin-Loaded Nanostructured Lipid Carriers against Porcine Epidemic Diarrhea Virus via Improved Intracellular Delivery

Porcine epidemic diarrhea virus (PEDV) is an acute enteric coronavirus, inducing watery diarrhea and high mortality in piglets, leading to huge economic losses in global pig industry. Ivermectin (IVM), an FDA-approved antiparasitic agent, is characterized by high efficacy and wide applicability. However, the poor bioavailability limits its application. Since the virus is parasitized inside the host cells, increasing the intracellular drug uptake can improve antiviral efficacy. Hence, we aimed to develop nanostructured lipid carriers (NLCs) to enhance the antiviral efficacy of IVM. The findings first revealed the capacity of IVM to inhibit the infectivity of PEDV by reducing viral replication with a certain direct inactivation effect. The as-prepared IVM-NLCs possessed hydrodynamic diameter of 153.5 nm with a zeta potential of -31.5 mV and high encapsulation efficiency (95.72%) and drug loading (11.17%). IVM interacted with lipids and was enveloped in lipid carriers with an amorphous state. Furthermore, its encapsulation in NLCs could enhance drug internalization. Meanwhile, IVM-NLCs inhibited PEDV proliferation by up to three orders of magnitude in terms of viral RNA copies, impeding the accumulation of reactive oxygen species and mitigating the mitochondrial dysfunction caused by PEDV infection. Moreover, IVM-NLCs markedly decreased the apoptosis rate of PEDV-induced Vero cells. Hence, IVM-NLCs showed superior inhibitory effect against PEDV compared to free IVM. Together, these results implied that NLCs is an efficient delivery system for IVM to improve its antiviral efficacy against PEDV via enhanced intracellular uptake.

Recent advances in metal-organic frameworks for stimuli-responsive drug delivery

After entering the human body, drugs for treating diseases, which are prone to delivery and release in an uncontrolled manner, are affected by various factors. Based on this, many researchers utilize various microenvironmental changes encountered during drug delivery to trigger drug release and have proposed stimuli-responsive drug delivery systems. In recent years, metal-organic frameworks (MOFs) have become promising stimuli-responsive agents to release the loaded therapeutic agents at the target site to achieve more precise drug delivery due to their high drug loading, excellent biocompatibility, and high stimuli-responsiveness. The MOF-based stimuli-responsive systems can respond to various stimuli under pathological conditions at the site of the lesion, releasing the loaded therapeutic agent in a controlled manner, and improving the accuracy and safety of drug delivery. Due to the changes in different physical and chemical factors in the pathological process of diseases, the construction of stimuli-responsive systems based on MOFs has become a new direction in drug delivery and controlled release. Based on the background of the rapidly increasing attention to MOFs applied in drug delivery, we aim to review various MOF-based stimuli-responsive drug delivery systems and their response mechanisms to various stimuli. In addition, the current challenges and future perspectives of MOF-based stimuli-responsive drug delivery systems are also discussed in this review.

Hijacking 5-Fluorouracil Chemoresistance in Triple Negative Breast Cancer via microRNAs-Loaded Chitosan Nanoparticles

Chemotherapy is still the mainstay of treatment for triple-negative breast cancer (TNBC) patients. Yet only 20% of TNBC patients show a pathologic complete response (pCR) after neoadjuvant chemotherapy. 5-Fluorouracil (5-FU) is a stable cornerstone in all recommended chemotherapeutic protocols for TNBC patients. However, TNBC patients' innate or acquired chemoresistance rate for 5-FU is steeply escalating. This study aims to unravel the mechanism behind the chemoresistance of 5-FU in the aggressive TNBC cell line, MDA-MB-231 cells, to explore further the role of the tumor suppressor microRNAs (miRNAs), miR-1275, miR-615-5p, and Let-7i, in relieving the 5-FU chemoresistance in TNBC, and to finally provide a translational therapeutic approach to co-deliver 5-FU and the respective miRNA oligonucleotides using chitosan-based nanoparticles (CsNPs). In this regard, cellular viability and proliferation were investigated using MTT and BrdU assays, respectively. 5-FU was found to induce JAK/STAT and PI3K/Akt/mTOR pathways in MDA-MB-231 cells with contaminant repression of their upstream regulators miR-1275, miR-615-5p, and Let-7i. Moreover, CsNPs prepared using the ionic gelation method were chosen and studied as nanovectors of 5-FU and a combination of miRNA oligonucleotides targeting TNBC. The average particle sizes, surface charges, and morphologies of the different CsNPs were characterized using dynamic light scattering (DLS) and transmission electron microscopy (TEM), respectively. In addition, the encapsulation efficiency (EE%), drug loading capacity (DLC%), and release manner at two different pH values were assessed. In conclusion, the novel CsNPs co-loaded with 5-FU and the combination of the three miRNA oligonucleotides demonstrated synergistic activity and remarkable repression in cellular viability and proliferation of TNBC cells through alleviating the chemoresistance to 5-FU.

LINC00467 mediates the 5-fluorouracil resistance in breast cancer cells

Breast cancer is a prevalent global disease that requires the development of effective therapeutic approaches. The occurrence of 5-fluorouracil (5-FU) resistance in breast cancer is emerging, which urgently needs new way to overcome the obstacle. In this study, we validated that the expression of LINC00467 is up-regulated in the breast cancer patients and breast cancer cells. In addition, the high expression of LINC00467 is associated with the 5-FU resistance of breast cancer cells. Interestingly, LINC00467 induced the homologous recombination (HR) repair via promoting the expression of NBS1 in 5-FU resistant breast cancer cells. Furthermore, miR-205 was validated as a common target of LINC00467 and NBS1, indicating that LINC00467 may induce NBS1 via the miRNA-mRNA target. Importantly, we identified that XBP1, as a transcription factor, induced the expression of LINC00467, which resulted in the enhanced HR efficiency and 5-FU resistance. Silencing XBP1 sensitized the 5-FU resistant breast cancer cells to the 5-FU treatment, whereas the ectopic expression of LINC00467 abrogated the effect of XBP1 silencing. In conclusion, LINC00467 enhances the 5-FU resistance by inducing NBS1-mediated DNA repair. LINC00467 also mediates the function of XBP1 in 5-FU resistance in breast cancer cells.

An updated landscape on nanotechnology-based drug delivery, immunotherapy, vaccinations, imaging, and biomarker detections for cancers: recent trends and future directions with clinical success

The recent development of nanotechnology-based formulations improved the diagnostics and therapies for various diseases including cancer where lack of specificity, high cytotoxicity with various side effects, poor biocompatibility, and increasing cases of multi-drug resistance are the major limitations of existing chemotherapy. Nanoparticle-based drug delivery enhances the stability and bioavailability of many drugs, thereby increasing tissue penetration and targeted delivery with improved efficacy against the tumour cells. Easy surface functionalization and encapsulation properties allow various antigens and tumour cell lysates to be delivered in the form of nanovaccines with improved immune response. The nanoparticles (NPs) due to their smaller size and associated optical, physical, and mechanical properties have evolved as biosensors with high sensitivity and specificity for the detection of various markers including nucleic acids, protein/antigens, small metabolites, etc. This review gives, initially, a concise update on drug delivery using different nanoscale platforms like liposomes, dendrimers, polymeric & various metallic NPs, hydrogels, microneedles, nanofibres, nanoemulsions, etc. Drug delivery with recent technologies like quantum dots (QDs), carbon nanotubes (CNTs), protein, and upconverting NPs was updated, thereafter. We also summarized the recent progress in vaccination strategy, immunotherapy involving immune checkpoint inhibitors, and biomarker detection for various cancers based on nanoplatforms. At last, we gave a detailed picture of the current nanomedicines in clinical trials and their possible success along with the existing approved ones. In short, this review provides an updated complete landscape of applications of wide NP-based drug delivery, vaccinations, immunotherapy, biomarker detection & imaging for various cancers with a predicted future of nanomedicines that are in clinical trials.

Quercetin: A Potential Polydynamic Drug

The study of natural products as potential drug leads has gained tremendous research interest. Quercetin is one of those natural products. It belongs to the family of flavonoids and, more specifically, flavonols. This review summarizes the beneficial pharmaceutical effects of quercetin, such as its anti-cancer, anti-inflammatory, and antimicrobial properties, which are some of the quercetin effects described in this review. Nevertheless, quercetin shows poor bioavailability and low solubility. For this reason, its encapsulation in macromolecules increases its bioavailability and therefore pharmaceutical efficiency. In this review, a brief description of the different forms of encapsulation of quercetin are described, and new ones are proposed. The beneficial effects of applying new pharmaceutical forms of nanotechnology are outlined.

Protection against cancer therapy-induced cardiovascular injury by planed-derived polyphenols and nanomaterials

Cancer therapy-induced heart injury is a significant concern for cancer patients undergoing chemotherapy, radiotherapy, immunotherapy, and also targeted molecular therapy. The use of these treatments can lead to oxidative stress and cardiomyocyte damage in the heart, which can result in heart failure and other cardiac complications. Experimental studies have revealed that chemotherapy drugs such as doxorubicin and cyclophosphamide can cause severe side effects such as cardiac fibrosis, electrophysiological remodeling, chronic oxidative stress and inflammation, etc., which may increase risk of cardiac disorders and attacks for patients that underwent chemotherapy. Similar consequences may also be observed for patients that undergo radiotherapy for left breast or lung malignancies. Polyphenols, a group of natural compounds with antioxidant and anti-inflammatory properties, have shown the potential in protecting against cancer therapy-induced heart injury. These compounds have been found to reduce oxidative stress, necrosis and apoptosis in the heart, thereby preserving cardiac function. In recent years, nanoparticles loaded with polyphenols have also provided for the delivery of these compounds and increasing their efficacy in different organs. These nanoparticles can improve the bioavailability and efficacy of polyphenols while minimizing their toxicity. This review article summarizes the current understanding of the protective effects of polyphenols and nanoparticles loaded with polyphenols against cancer therapy-induced heart injury. The article discusses the mechanisms by which polyphenols protect the heart, including antioxidant and anti-inflammation abilities. The article also highlights the potential benefits of using nanoparticles for the delivery of polyphenols.

Pharmacomicrobiomics of cell-cycle specific anti-cancer drugs - is it a new perspective for personalized treatment of cancer patients?

Intestinal bacteria are equipped with an enzyme apparatus that is involved in the active biotransformation of xenobiotics, including drugs. Pharmacomicrobiomics, a new area of pharmacology, analyses interactions between bacteria and xenobiotics. However, there is another side to the coin. Pharmacotherapeutic agents can significantly modify the microbiota, which consequently affects their efficacy. In this review, we comprehensively gathered scientific evidence on the interplay between anticancer therapies and gut microbes. We also underlined how such interactions might impact the host response to a given therapy. We discuss the possibility of modulating the gut microbiota to increase the effectiveness/decrease the incidence of adverse events during tumor therapy. The anticipation of the future brings new evidence that gut microbiota is a target of interest to increase the efficacy of therapy.

Physicochemical Properties and Release Study of Antimetabolite-Incorporated Stearoyl Chitosan

Stearoyl chitosan (SC), derived from the acylation of chitosan, contributes to the efficiency of drug delivery systems because of its structure, which accommodates the drug in a particle. Nonetheless, its role in chemotherapy has been largely unexplored. The present study involves the synthesis of stearoyl chitosan through the reaction of depolymerized chitosan with stearoyl chloride under mild reaction conditions. The resulting compound was subjected to structural analysis utilizing Fourier-transform infrared (FTIR) spectroscopy, 1H NMR, and X-ray diffraction (XRD) spectroscopy. The dispersion of SC molecules in phosphate-buffered saline (PBS) forms SC nanoparticles. The best dispersion of SC in the solution was achieved at a 1:60 chitosan-to-stearoyl chloride weight ratio. Three antimetabolite drugs, methotrexate, pemetrexed, and raltitrexed, were selected to examine the loading efficacy of SC. Pemetrexed had the highest drug-loading value of 36.8% among the three antimetabolites incorporated into SC, along with an encapsulation efficiency of 85.1%. The size of SC loaded with antimetabolites ranged from 225 to 369 nm, and their spherical form was verified via a transmission electron microscope. The in vitro release study showed that SC demonstrated controlled drug release, suggesting that SC nanoparticles have significant promise as a delivery strategy for chemotherapy.

Quercetin and 5-Fu Loaded Chitosan Nanoparticles Trigger Cell-Cycle Arrest and Induce Apoptosis in HCT116 Cells via Modulation of the p53/p21 Axis

Nanoparticles (NPs) are encapsulating agents that exist in the nanometer range. They can be classified into different classes based on their properties, shapes, or sizes. Metal NPs, fullerenes, polymeric NPs, ceramic NPs, and luminescent nanoporous hybrid materials are only a few examples. This study explored the anticancer potential of quercetin and 5-fluorouracil-encapsulated chitosan nanoparticles (CS-5-FU-QCT NPs). The nanoparticles were prepared by ionic gelation, and their efficacy and mechanism of action were examined. CS-5-FU-QCT NPs were characterized using dynamic light scattering (DLS), atomic force microscopy (AFM), UV-visible spectroscopy, and Fourier transform infrared spectroscopy (FTIR); cytotoxicity was analyzed using an MTT assay. Cells were treated with CS-5-FU-QCT NPs and incubated for 12, 24, and 36 h, and apoptosis analysis (using Annexin V/FITC), cell-cycle analysis, Western blotting, and confocal microscopic analysis were performed. Biophysical analysis revealed that the CS-5-FU-QCT NPs fall in the range of 300-400 nm with a near-spherical shape. The in vitro drug release profile indicates sustained release of drugs over a period of about 36 h. The cytotoxicity of CS-5-FU-QCT NPs was more prominent in HCT116 cells than in other cancer cells. This particular nanoformulation caused G0/G1 phase cell-cycle arrest in HCT116 cells and induced intracellular ROS generation, thereby causing apoptosis. It also downregulated Bcl2, cyclin D1, and Cdk4 and upregulated BAX, p53, and p21, causing cell-cycle arrest and apoptosis. In summary, CS-5-FU-QCT NPs hindered proliferation of HCT116 cells via ROS generation and altered the expression of key proteins in the p53/p21 axis and apoptotic machinery in a time-dependent manner.

scFv biofunctionalized nanoparticles to effective and safe targeting of CEA-expressing colorectal cancer cells

Colorectal cancer (CRC) is one of the deadliest cancers worldwide, with the 5 year survival rate in metastatic cases limited to 12%. The design of targeted and effective therapeutics remains a major unmet clinical need in CRC treatment. Carcinoembryonic antigen (CEA), a glycoprotein overexpressed in most colorectal tumors, may constitute a promising molecule for generating novel CEA-targeted therapeutic strategies for CRC treatment. Here, we developed a smart nanoplatform based on chemical conjugation of an anti-CEA single-chain variable fragment (scFv), MFE-23, with PLGA-PEG polymers to deliver the standard 5-Fluorouracil (5-FU) chemotherapy to CRC cells. We confirmed the specificity of the developed CEA-targeted NPs on the internalization by CEA-expressing CRC cells, with an enhance of threefold in the cell uptake. Additionally, CEA-targeted NPs loaded with 5-FU induced higher cytotoxicity in CEA-expressing cells, after 24 h and 48 h of treatment, reinforcing the specificity of the targeted NPs. Lastly, the safety of CEA-targeted NPs loaded with 5-FU was evaluated in donor-isolated macrophages, with no relevant impact on their metabolic activity nor polarization. Altogether, this proof of concept supports the CEA-mediated internalization of targeted NPs as a promising chemotherapeutic strategy for further investigation in different CEA-associated cancers and respective metastatic sites.Authors: Please confirm if the author names are presented accurately and in the correct sequence (given name, middle name/initial, family name). Author 1 Given name: [Maria José] Last name [Silveira]. Author 7 Given name: [Maria José] Last name [Oliveira]. Also, kindly confirm the details in the metadata are correctokAffiliations: Please check and confirm that the authors and their respective affiliations have been correctly identified and amend if necessary.ok.

Preparation and characterization of pH-sensitive chitosan/starch/MoS2 nanocomposite for control release of curcumin macromolecules drug delivery; application in the breast cancer treatment

In this work, chitosan (CS), Starch (S), and Molybdenum Disulfide (MoS2) were combined to create a nanocarrier that was utilized to treat breast cancer using the MCF-7 cell line. To analyze the features of the nanocarrier, Fourier-transform infrared spectroscopy (FTIR) and X-Ray diffraction (XRD) tests were performed, respectively, to discover physical interactions and chemical bonding. Field emission scanning electron microscopy (FE-SEM), Dynamic light scattering (DLS), and zeta potential analyses were performed and reported to determine the structural characteristics and morphology of nanoparticles, size distribution, and surface charge of nanocarriers, respectively. The average size of the nanocomposite was measured at around 279 nm, and the surface charge of the nanocarrier was determined to be +86.31 mV. The entrapment and drug loading efficiency of nanocarriers were 87.25 % and 46.5 %, respectively, which is an acceptable value. The kinetics and release mode of the drug were investigated, and it was found that the synthesized nanocarrier was sensitive to pH and that its release was stable. The amount of the nanocarriers' toxicity and cell death were evaluated using MTT tests and flow cytometry, respectively. In the present study, the nanocarrier was wholly nontoxic and had anticancer properties against the MCF-7 cell line. This nanocarrier is very important due to its non-toxicity and sensitivity to pH and can be used in drug delivery and medical applications.

The improving strategies and applications of nanotechnology-based drugs in hepatocellular carcinoma treatment

Hepatocellular carcinoma (HCC) is one of the leading causes of tumor-related death worldwide. Conventional treatments for HCC include drugs, radiation, and surgery. Despite the unremitting efforts of researchers, the curative effect of HCC has been greatly improved, but because HCC is often found in the middle and late stages, the curative effect is still not satisfactory, and the 5-year survival rate is still low. Nanomedicine is a potential subject, which has been applied to the treatment of HCC and has achieved promising results. Here, we summarized the factors affecting the efficacy of drugs in HCC treatment and the strategies for improving the efficacy of nanotechnology-based drugs in HCC, reviewed the recent applications' progress on nanotechnology-based drugs in HCC treatment, and discussed the future perspectives and challenges of nanotechnology-based drugs in HCC treatment.

Thermosensitive Hydrogel-Functionalized Mesoporous Silica Nanoparticles for Parenteral Application of Chemotherapeutics

Hydrogels can offer many opportunities for drug delivery strategies. They can be used on their own, or their benefits can be further exploited in combination with other nanocarriers. Intelligent hydrogels that react to changes in the surrounding environment can be utilized as gatekeepers and provide sustained on-demand drug release. In this study, a hybrid nanosystem for temperature- and pH-sensitive delivery was prepared from MCM-41 nanoparticles grafted with a newly synthesized thermosensitive hydrogel (MCM-41/AA-g-PnVCL). The initial particles were chemically modified by the attachment of carboxyl groups. Later, they were grafted with agar (AA) and vinylcaprolactam (VCL) by free radical polymerization. Doxorubicin was applied as a model hydrophilic chemotherapeutic drug. The successful formulation was confirmed by FT-IR and TGA. Transmission electron microscopy and dynamic light scattering analysis showed small particles with negative zeta potential. Their release behaviour was investigated in vitro in media with different pH and at different temperatures. Under tumour simulating conditions (40 °C and pH 4.0), doxorubicin was almost completely released within 72 h. The biocompatibility of the proposed nanoparticles was demonstrated by in vitro haemolysis assay. These results suggest the possible parenteral application of the newly prepared hydrogel-functionalized mesoporous silica nanoparticles for temperature-sensitive and pH-triggered drug delivery at the tumour site.

A pH-responsive bi-MIL-88B MOF coated with folic acid-conjugated chitosan as a promising nanocarrier for targeted drug delivery of 5-Fluorouracil

Cancer has remained one of the leading causes of death worldwide, with a lack of effective treatment. The intrinsic shortcomings of conventional therapeutics regarding tumor specificity and non-specific toxicity prompt us to look for alternative therapeutics to mitigate these limitations. In this regard, we developed multifunctional bimetallic (FeCo) bi-MIL-88B-FC MOFs modified with folic acid-conjugated chitosan (FC) as drug delivery systems (DDS) for targeted delivery of 5-Fluorouracil (5-FU). The bi-MIL-88B nanocarriers were characterized through various techniques, including powder X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray, thermogravimetric analysis, and Fourier transform infrared spectroscopy. Interestingly, 5-FU@bi-MIL-88B-FC showed slower release of 5-FU due to a gated effect phenomenon endowed by FC surface coating compared to un-modified 5-FU@bi-MIL-88B. The pH-responsive drug release was observed, with 58% of the loaded 5-FU released in cancer cells mimicking pH (5.2) compared to only 24.9% released under physiological pH (5.4). The in vitro cytotoxicity and cellular internalization experiments revealed the superiority of 5-FU@bi-MIL-88B-FC as a highly potent targeted DDS against folate receptor (FR) positive SW480 cancer cells. Moreover, due to the presence of Fe and Co in the structure, bi-MIL-88B exhibited peroxidase-like activity for chemodynamic therapy. Based on the results, 5-FU@bi-MIL-88B-FC could serve as promising candidate for smart DDS by sustained drug release and selective targeting.

Calcium Orthophosphate in Liposomes for Co-Delivery of Doxorubicin Hydrochloride/Paclitaxel in Breast Cancer

Nanoparticles (NPs) show great advantages in cancer treatment by enabling controlled and targeted delivery of payloads to tumor sites through the enhanced permeability and retention (EPR) effect. In this study, highly effective pH-responsive and biodegradable calcium orthophosphate@liposomes (CaP@Lip) NPs with a diameter of 110 ± 20 nm were designed and fabricated. CaP@Lip NPs loaded with hydrophobic paclitaxel and hydrophilic doxorubicin hydrochloride achieved excellent drug loading efficiencies of 70 and 90%, respectively. Under physiological conditions, the obtained NPs are negatively charged. However, they switched to positively charged when exposed to weak acidic environments by which internalization can be promoted. Furthermore, the CaP@Lip NPs exhibit an obvious structural collapse under acid conditions (pH 5.5), which confirms their excellent biodegradability. The "proton expansion" effect in endosomes and the pH-responsiveness of the NPs facilitate the release of encapsulated drugs from individual channels. The effectiveness and safety of the drug delivery systems were demonstrated through in vitro and in vivo experiments, with a 76% inhibition of tumor growth. These findings highlight the high targeting ability of the drug-loaded NPs to tumor sites through the EPR effect, effectively suppressing tumor growth and metastasis. By combining CaP NPs and liposomes, this study not only resolves the toxicity of CaP but also enhances the stability of liposomes. The CaP@Lip NPs developed in this study have significant implications for biomedical applications and inspire the development of intelligent and smart drug nanocarriers and release systems for clinical use.

Sorafenib-Based Drug Delivery Systems: Applications and Perspectives

As a Food and Drug Administration (FDA)-approved molecular-targeted chemotherapeutic drug, sorafenib (SF) can inhibit angiogenesis and tumor cell proliferation, leading to improved patient overall survival of hepatocellular carcinoma (HCC). In addition, SF is an oral multikinase inhibitor as a single-agent therapy in renal cell carcinoma. However, the poor aqueous solubility, low bioavailability, unfavorable pharmacokinetic properties and undesirable side effects (anorexia, gastrointestinal bleeding, and severe skin toxicity, etc.) seriously limit its clinical application. To overcome these drawbacks, the entrapment of SF into nanocarriers by nanoformulations is an effective strategy, which delivers SF in a target tumor with decreased adverse effects and improved treatment efficacy. In this review, significant advances and design strategies of SF nanodelivery systems from 2012 to 2023 are summarized. The review is organized by type of carriers including natural biomacromolecule (lipid, chitosan, cyclodextrin, etc.); synthetic polymer (poly(lactic-co-glycolic acid), polyethyleneimine, brush copolymer, etc.); mesoporous silica; gold nanoparticles; and others. Co-delivery of SF and other active agents (glypican-3, hyaluronic acid, apolipoprotein peptide, folate, and superparamagnetic iron oxide nanoparticles) for targeted SF nanosystems and synergistic drug combinations are also highlighted. All these studies showed promising results for targeted treatment of HCC and other cancers by SF-based nanomedicines. The outlook, challenges and future opportunities for the development of SF-based drug delivery are presented.

Current Principles, Challenges, and New Metrics in pH-Responsive Drug Delivery Systems for Systemic Cancer Therapy

The paradigm of drug delivery via particulate formulations is one of the leading ideas that enable overcoming limitations of traditional chemotherapeutic agents. The trend toward more complex multifunctional drug carriers is well-traced in the literature. Nowadays, the prospectiveness of stimuli-responsive systems capable of controlled cargo release in the lesion nidus is widely accepted. Both endogenous and exogenous stimuli are employed for this purpose; however, endogenous pH is the most common trigger. Unfortunately, scientists encounter multiple challenges on the way to the implementation of this idea related to the vehicles' accumulation in off-target tissues, their immunogenicity, the complexity of drug delivery to intracellular targets, and finally, the difficulties in the fabrication of carriers matching all imposed requirements. Here, we discuss fundamental strategies for pH-responsive drug delivery, as well as limitations related to such carriers' application, and reveal the main problems, weaknesses, and reasons for poor clinical results. Moreover, we attempted to formulate the profiles of an "ideal" drug carrier in the frame of different strategies drawing on the example of metal-comprising materials and considered recently published studies through the lens of these profiles. We believe that this approach will facilitate the formulation of the main challenges facing researchers and the identification of the most promising trends in technology development.

Therapeutic applications of nanobiotechnology

Nanobiotechnology, as a novel and more specialized branch of science, has provided a number of nanostructures such as nanoparticles, by utilizing the methods, techniques, and protocols of other branches of science. Due to the unique features and physiobiological characteristics, these nanostructures or nanocarriers have provided vast methods and therapeutic techniques, against microbial infections and cancers and for tissue regeneration, tissue engineering, and immunotherapies, and for gene therapies, through drug delivery systems. However, reduced carrying capacity, abrupt and non-targeted delivery, and solubility of therapeutic agents, can affect the therapeutic applications of these biotechnological products. In this article, we explored and discussed the prominent nanobiotechnological methods and products such as nanocarriers, highlighted the features and challenges associated with these products, and attempted to conclude if available nanostructures offer any scope of improvement or enhancement. We aimed to identify and emphasize the nanobiotechnological methods and products, with greater prospect and capacity for therapeutic improvements and enhancements. We found that novel nanocarriers and nanostructures, such as nanocomposites, micelles, hydrogels, microneedles, and artificial cells, can address the associated challenges and inherited drawbacks, with help of conjugations, sustained and stimuli-responsive release, ligand binding, and targeted delivery. We recommend that nanobiotechnology, despite having few challenges and drawbacks, offers immense opportunities that can be harnessed in delivering quality therapeutics with precision and prediction. We also recommend that, by exploring the branched domains more rigorously, bottlenecks and obstacles can also be addressed and resolved in return.

A Facile Fluorometric Assay of Orotate Phosphoribosyltransferase Activity Using a Selective Fluorogenic Reaction for Orotic Acid

Orotate phosphoribosyltransferase (OPRT) exists as a bifunctional enzyme, uridine 5'-monophosphate synthase, in mammalian cells and plays an important role in pyrimidine biosynthesis. Measuring OPRT activity has been considered important for understanding biological events and development of molecular-targeting drugs. In this study, we demonstrate a novel fluorescence method for measuring OPRT activity in living cells. The technique utilizes 4-trifluoromethylbenzamidoxime (4-TFMBAO) as a fluorogenic reagent, which produces selective fluorescence for orotic acid. To perform the OPRT reaction, orotic acid was added to HeLa cell lysate, and a portion of the enzyme reaction mixture was heated at 80 °C for 4 min in the presence of 4-TFMBAO under basic conditions. The resulting fluorescence was measured using a spectrofluorometer, which reflects the consumption of orotic acid by the OPRT. After optimization of the reaction conditions, the OPRT activity was successfully determined in 15 min of enzyme reaction time without further procedures such as purification of OPRT or deproteination for the analysis. The activity obtained was compatible with the value measured by the radiometric method with [³H]-5-FU as the substrate. The present method provides a reliable and facile measurement of OPRT activity and could be useful for a variety of research fields targeting pyrimidine metabolism.