5-Fluorouracil: forty-plus and still ticking. A review of its preclinical and clinical development

Protein Structure Inspired Discovery of a Novel Inducer of Anoikis in Human Melanoma

Drug discovery historically starts with an established function, either that of compounds or proteins. This can hamper discovery of novel therapeutics. As structure determines function, we hypothesized that unique 3D protein structures constitute primary data that can inform novel discovery. Using a computationally intensive physics-based analytical platform operating at supercomputing speeds, we probed a high-resolution protein X-ray crystallographic library developed by us. For each of the eight identified novel 3D structures, we analyzed binding of sixty million compounds. Top-ranking compounds were acquired and screened for efficacy against breast, prostate, colon, or lung cancer, and for toxicity on normal human bone marrow stem cells, both using eight-day colony formation assays. Effective and non-toxic compounds segregated to two pockets. One compound, Dxr2-017, exhibited selective anti-melanoma activity in the NCI-60 cell line screen. In eight-day assays, Dxr2-017 had an IC50 of 12 nM against melanoma cells, while concentrations over 2100-fold higher had minimal stem cell toxicity. Dxr2-017 induced anoikis, a unique form of programmed cell death in need of targeted therapeutics. Our findings demonstrate proof-of-concept that protein structures represent high-value primary data to support the discovery of novel acting therapeutics. This approach is widely applicable.

Esterase-Responsive Floxuridine-Tethered Multifunctional Nanoparticles for Targeted Cancer Therapy

Floxuridine is a potential clinical anticancer drug for the treatment of various cancers. However, floxuridine typically causes unfavorable side effects due to its very poor tumor selectivity, and, hence, there is a high demand for the development of novel approaches that permit the targeted delivery of floxuridine into cancerous cells. Herein, the design and synthesis of an esterase-responsive multifunctional nanoformulation for the targeted delivery of floxuridine in esterase-overexpressed cancer cells is reported. Photopolymerization of floxuridine-tethered lipoic acid results in the formation of amphiphilic floxuridine-tethered poly(disulfide). Self-assembly of the amphiphilic polymer results in the formation of nanoparticles with floxuridine decorated on the surfaces of the particles. Integration of aptamer DNA for nucleolin onto the surface of the nanoparticle is demonstrated by exploring the base-pairing interaction of floxuridine with adenine. Targeted internalization of the aptamer-decorated nanoparticle into nucleolin-expressed cancer cells is demonstrated. Esterase triggered cleavage of the ester bond connecting floxuridine with the polymer backbone, and the subsequent targeted delivery of floxuridine into cancer cells is also shown. Excellent therapeutic efficacy is observed both in vitro and also in the 3D tumor spheroid model. This noncovalent strategy provides a simple yet effective strategy for the targeted delivery of floxuridine into cancer cells in a less laborious fashion.

Polysaccharide-based emulsion gels for the prevention of postoperative adhesions and as a drug delivery system using 5-fluorouracil

Postoperative tissue adhesion is a well-recognized and common complication. Despite ongoing developments in anti-adhesion agents, complete prevention remains a challenge in clinical practice. Colorectal cancer necessitates both adhesion prevention and postoperative chemotherapy. Accordingly, drug-loading into an anti-adhesion agent could be employed as a treatment strategy to maximize the drug effects through local application and minimize side effects. Herein, we introduce an anti-adhesion agent that functions as a drug delivery system by loading drugs within an emulsion that forms a gel matrix in the presence of polysaccharides, xanthan gum, and pectin. Based on the rheological analysis, the xanthan gum-containing emulsion gel formed a gel matrix with suitable strength and mucosal adhesiveness. In vitro dissolution tests demonstrated sustained drug release over 12 h, while in vivo pharmacokinetic studies revealed a significant increase in the Tmax (up to 4.03 times) and area under the curve (up to 2.62 times). However, most of the drug was released within one day, distributing systemically and raising toxicity concerns, thus limiting its efficacy as a controlled drug delivery system. According to in vivo anti-adhesion efficacy evaluations, the xanthan gum/pectin emulsion gels, particularly F2 and F3, exhibited remarkable anti-adhesion capacity (P < 0.01). The emulsion gel formulation exhibited no cytotoxicity against fibroblasts or epithelial cell lines. Thus, the xanthan gum/pectin emulsion gel exhibits excellent anti-adhesion properties and could be developed as a drug delivery system.

Gynotoxic Effects of Chemotherapy and Potential Protective Mechanisms

Chemotherapy is one of the leading cancer treatments. Unfortunately, its use can contribute to several side effects, including gynotoxic effects in women. Ovarian reserve suppression and estrogen deficiency result in reduced quality of life for cancer patients and are frequently the cause of infertility and early menopause. Classic alkylating cytostatics are among the most toxic chemotherapeutics in this regard. They cause DNA damage in ovarian follicles and the cells they contain, and they can also induce oxidative stress or affect numerous signaling pathways. In vitro tests, animal models, and a few studies among women have investigated the effects of various agents on the protection of the ovarian reserve during classic chemotherapy. In this review article, we focused on the possible beneficial effects of selected hormones (anti-Müllerian hormone, ghrelin, luteinizing hormone, melatonin), agents affecting the activity of apoptotic pathways and modulating gene expression (C1P, S1P, microRNA), and several natural (quercetin, rapamycin, resveratrol) and synthetic compounds (bortezomib, dexrazoxane, goserelin, gonadoliberin analogs, imatinib, metformin, tamoxifen) in preventing gynotoxic effects induced by commonly used cytostatics. The presented line of research appears to provide a promising strategy for protecting and/or improving the ovarian reserve in the studied group of cancer patients. However, well-designed clinical trials are needed to unequivocally assess the effects of these agents on improving hormonal function and fertility in women treated with ovotoxic anticancer drugs.

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.

Biochemical hallmarks-targeting antineoplastic nanotherapeutics

Tumor microenvironments (TMEs) have received increasing attention in recent years as they play pivotal roles in tumorigenesis, progression, metastases, and resistance to the traditional modalities of cancer therapy like chemotherapy. With the rapid development of nanotechnology, effective antineoplastic nanotherapeutics targeting the aberrant hallmarks of TMEs have been proposed. The appropriate design and fabrication endow nanomedicines with the abilities for active targeting, TMEs-responsiveness, and optimization of physicochemical properties of tumors, thereby overcoming transport barriers and significantly improving antineoplastic therapeutic benefits. This review begins with the origins and characteristics of TMEs and discusses the latest strategies for modulating the TMEs by focusing on the regulation of biochemical microenvironments, such as tumor acidosis, hypoxia, and dysregulated metabolism. Finally, this review summarizes the challenges in the development of smart anti-cancer nanotherapeutics for TME modulation and examines the promising strategies for combination therapies with traditional treatments for further clinical translation.

Protein Structure Inspired Drug Discovery

Drug discovery starts with known function, either of a compound or a protein, in-turn prompting investigations to probe 3D structure of the compound-protein interface. As protein structure determines function, we hypothesized that unique 3D structural motifs represent primary information denoting unique function that can drive discovery of novel agents. Using a physics-based protein structure analysis platform developed by us, designed to conduct computationally intensive analysis at supercomputing speeds, we probed a high-resolution protein x-ray crystallographic library developed by us. We selected 3D structural motifs whose function was not otherwise established, that offered environments supporting binding of drug-like chemicals and were present on proteins that were not established therapeutic targets. For each of eight potential binding pockets on six different proteins we accessed a 60 million compound library and used our analysis platform to evaluate binding. Using eight-day colony formation assays acquired compounds were screened for efficacy against human breast, prostate, colon and lung cancer cells and toxicity against human bone marrow stem cells. Compounds selectively inhibiting cancer growth segregated to two pockets on separate proteins. The compound, Dxr2-017, exhibited selective activity against human melanoma cells in the NCI-60 cell line screen, had an IC50 of 19 nM against human melanoma M14 cells in our eight-day assay, while over 2100-fold higher concentrations inhibited stem cells by less than 30%. We show that Dxr2-017 induces anoikis, a unique form of programmed cell death in need of targeted therapeutics. The predicted target protein for Dxr2-017 is expressed in bacteria, not in humans. This supports our strategy of focusing on unique 3D structural motifs. It is known that functionally important 3D structures are evolutionarily conserved. Here we demonstrate proof-of-concept that protein structure represents high value primary data to support discovery of novel therapeutics. This approach is widely applicable.

A phase I open-label, dose-escalation study of NUC-3373, a targeted thymidylate synthase inhibitor, in patients with advanced cancer (NuTide:301)

PURPOSE

5-fluorouracil (5-FU) is inefficiently converted to the active anti-cancer metabolite, fluorodeoxyuridine-monophosphate (FUDR-MP), is associated with dose-limiting toxicities and challenging administration schedules. NUC-3373 is a phosphoramidate nucleotide analog of fluorodeoxyuridine (FUDR) designed to overcome these limitations and replace fluoropyrimidines such as 5-FU.

PATIENTS AND METHODS

NUC-3373 was administered as monotherapy to patients with advanced solid tumors refractory to standard therapy via intravenous infusion either on Days 1, 8, 15 and 22 (Part 1) or on Days 1 and 15 (Part 2) of 28-day cycles until disease progression or unacceptable toxicity. Primary objectives were maximum tolerated dose (MTD) and recommended Phase II dose (RP2D) and schedule of NUC-3373. Secondary objectives included pharmacokinetics (PK), and anti-tumor activity.

RESULTS

Fifty-nine patients received weekly NUC-3373 in 9 cohorts in Part 1 (n = 43) and 3 alternate-weekly dosing cohorts in Part 2 (n = 16). They had received a median of 3 prior lines of treatment (range: 0-11) and 74% were exposed to prior fluoropyrimidines. Four experienced dose-limiting toxicities: two Grade (G) 3 transaminitis; one G2 headache; and one G3 transient hypotension. Commonest treatment-related G3 adverse event of raised transaminases occurred in < 10% of patients. NUC-3373 showed a favorable PK profile, with dose-proportionality and a prolonged half-life compared to 5-FU. A best overall response of stable disease was observed, with prolonged progression-free survival.

CONCLUSION

NUC-3373 was well-tolerated in a heavily pre-treated solid tumor patient population, including those who had relapsed on prior 5-FU. The MTD and RP2D was defined as 2500 mg/m2 NUC-3373 weekly. NUC-3373 is currently in combination treatment studies.

TRIAL REGISTRATION

Clinicaltrials.gov registry number NCT02723240. Trial registered on 8th December 2015. https://clinicaltrials.gov/study/NCT02723240 .

IMPRINTS.CETSA and IMPRINTS.CETSA.app: an R package and a Shiny application for the analysis and interpretation of IMPRINTS-CETSA data

IMPRINTS-CETSA (Integrated Modulation of Protein Interaction States-Cellular Thermal Shift Assay) provides a highly resolved means to systematically study the interactions of proteins with other cellular components, including metabolites, nucleic acids and other proteins, at the proteome level, but no freely available and user-friendly data analysis software has been reported. Here, we report IMPRINTS.CETSA, an R package that provides the basic data processing framework for robust analysis of the IMPRINTS-CETSA data format, from preprocessing and normalization to visualization. We also report an accompanying R package, IMPRINTS.CETSA.app, which offers a user-friendly Shiny interface for analysis and interpretation of IMPRINTS-CETSA results, with seamless features such as functional enrichment and mapping to other databases at a single site. For the hit generation part, the diverse behaviors of protein modulations have been typically segregated with a two-measure scoring method, i.e. the abundance and thermal stability changes. We present a new algorithm to classify modulated proteins in IMPRINTS-CETSA experiments by a robust single-measure scoring. In this way, both the numerical changes and the statistical significances of the IMPRINTS information can be visualized on a single plot. The IMPRINTS.CETSA and IMPRINTS.CETSA.app R packages are freely available on GitHub at https://github.com/nkdailingyun/IMPRINTS.CETSA and https://github.com/mgerault/IMPRINTS.CETSA.app, respectively. IMPRINTS.CETSA.app is also available as an executable program at https://zenodo.org/records/10636134.

Herbal compounds as promising therapeutic agents in precision medicine strategies for cancer: A systematic review

BACKGROUND

The field of personalized medicine has gained increasing attention in cancer care, with the aim of tailoring treatment strategies to individual patients for improved outcomes. Herbal medicine, with its long-standing historical use and extensive bioactive compounds, offers a rich source of potential treatments for various diseases, including cancer.

OBJECTIVE

To provide an overview of the current knowledge and evidence associated with incorporating herbal compounds into precision medicine strategies for cancer diseases. Additionally, to explore the general characteristics of the studies included in the analysis, focusing on their key features and trends.

SEARCH STRATEGY

A comprehensive literature search was conducted from multiple online databases, including PubMed, Scopus, Web of Science, and CINAHL-EBSCO. The search strategy was designed to identify studies related to personalized cancer medicine and herbal interventions.

INCLUSION CRITERIA

Publications pertaining to cancer research conducted through in vitro, in vivo, and clinical studies, employing natural products were included in this review.

DATA EXTRACTION AND ANALYSIS

Two review authors independently applied inclusion and inclusion criteria, data extraction, and assessments of methodological quality. The quality assessment and biases of the studies were evaluated based on modified Jadad scales. A detailed quantitative summary of the included studies is presented, providing a comprehensive description of their key features and findings.

RESULTS

A total of 121 studies were included in this review for analysis. Some of them were considered as comprehensive experimental investigations both in vitro and in vivo. The majority (n = 85) of the studies included in this review were conducted in vitro, with 44 of them specifically investigating the effects of herbal medicine on animal models. Additionally, 7 articles with a combined sample size of 31,271 patients, examined the impact of herbal medicine in clinical settings.

CONCLUSION

Personalized medication can optimize the use of herbal medicine in cancer treatment by considering individual patient factors such as genetics, medical history, and other treatments. Additionally, active phytochemicals found in herbs have shown potential for inhibiting cancer cell growth and inducing apoptosis, making them a promising area of research in preclinical and clinical investigations. Please cite this article as: Tayeb BA, Kusuma IY, Osman AAM, Minorics R. Herbal compounds as promising therapeutic agents in precision medicine strategies for cancer: A systematic review. J Integr Med. 2024; 22(2): 137-162.

Tracking the binding site of anticancer drug fluxoridin with Fe-related proteins to achieve intelligent drug delivery

In cancer cells that need a lot of iron for growth and metastasis, halo-transferrin (TF-containing iron) enters the cell with the help of the transferrin receptor 1 (TFR1) protein. If the anticancer drug can bind to the iron site by interacting with apo-transferrin (iron-free FT), it can enter the cancer cell by the same mechanism. Two iron-related proteins, Bovine liver catalase (BLC) and apo-Transferrin (TF), that are important in cancer patients were selected and their interaction with the anti-cancer drug Floxuridine (FUDR) was investigated. Here, the protective role of FUDR was evaluated by several variables such as drug concentration, interaction time, and temperature-induced degradation of enzyme function. The results showed that the protective effect of the FUDR is greater in high concentrations (in 5 × 10-5 M:1.78 % and 2.59 % after 24 and 48 h). The interaction of the FUDR with both proteins can reduce the intensity of the fluorescence emission by a static mechanism. The binding strength of the FUDR with both proteins was almost similar and with the order of 104 M-1 (Kb = 3.90 ± 0.41 × 104 M-1 for BLC-FUDR and 5.01 ± 0.36 × 104 M-1 for TF-FUDR at 310 K). The thermodynamic calculations (in agreement with the docking results) indicated that FUDR-protein complex formation was exothermic and the main binding forces in the binding process were van der Waals interactions and hydrogen bonds. Both fluorophores tryptophan (Trp) and tyrosine (Tyr) of both proteins had significant roles in fluorescence quenching and the interaction process, the polarity of their microenvironment changed. CD results showed that the secondary structure changes of TF are slightly more than BLC. Molecular docking showed that the binding of the FUDR to TF is very close to the Fe-specific site and is placed in the cavity among the wrapping domain, N-Terminal arm, and β-barrel in BLC.

Potential of fluoropyrimidine to be an immunologically optimal partner of immune checkpoint inhibitors through inducing immunogenic cell death for thoracic malignancies

BACKGROUND

Immune checkpoint inhibitors (ICIs) are a revolutionary paradigm in the treatment of thoracic malignancies and chemoimmunotherapy is a current standard care in this field. Chemotherapeutic agents are known to induce not only direct cytotoxic effects on tumor cells but also immune modulating effects, such as stimulating immunogenic cell death (ICD). Currently, either pemetrexed (PEM) or taxane plus platinum are combined with ICIs for patients with non-small cell lung cancer (NSCLC); however, it is still unknown whether these agents are immunologically optimal partners for ICIs.

METHODS

To determine the immunologically optimal chemotherapeutic agent, we first evaluated the ability of several chemotherapeutic agents, including platinum, PEM, taxane, and 5-fluorouracil (5-FU) to induce ICD using several thoracic tumor cell lines in vitro. ICD was evaluated by the cell surface expression of calreticulin (CRT) and adenosine-triphosphate (ATP) secretion. We further performed an antitumor vaccination assay in vivo.

RESULTS

5-FU induced cell surface expression of CRT and ATP secretion most efficiently among the several chemotherapeutic agents. This effect was enhanced when it was combined with platinum. In the antitumor vaccination assay in vivo, we found that vaccination with dying-AB1-HA (a murine malignant mesothelioma cell line) cells treated with 5-FU, but neither PEM nor PTX, reduced the tumor growth of living-AB1-HA cells inoculated 1 week after vaccination by recruiting CD3+ CD8+ T cells into the tumor microenvironment.

CONCLUSION

Our findings indicate that fluoropyrimidine can be an immunologically optimal partner of ICIs through the induction of ICD for thoracic malignancies.

Treatment efficacy of low-dose 5-fluorouracil with ultrasound in mediating 5-fluorouracil-loaded microbubble cavitation in head and neck cancer

Over the past 50 years, 5-fluorouracil (5-FU) has played a critical role in the systemic chemotherapy of cancer patients. Bolus intravenous (IV) 5-FU infusion has been used due to the limitation of its extremely short half-life (10-15 min). This study used ultrasound (US) mediating 5-FU-loaded microbubbles (MBs) cavitation as a tool to increase local intratumoral 5-FU levels with a reduced dose of 5-FU (a single IV injection of 2.5 mg/kg instead of a single intraperitoneal injection of 25-200 mg/kg as used in previous studies in mice). The 5-FU-MBs were prepared with a 132 mg/mL albumin solution and a 0.30 mg/mL 5-FU solution. The diameters of the MBs and 5-FU-MBs were 1.24 ± 0.85 and 2.00 ± 0.53 µm (mean ± SEM), respectively, and the maximum loading efficiency of 5-FU on MBs was 19.04 ± 0.25%. In the in vitro study, the cell viabilities of 5-FU and 5-FU-MBs did not differ significantly, but compared with the 5-FU-MBs treatment-alone group, cell toxicity increased to 31% in the 5-FU-MBs + US group (p < 0.001). The biodistribution results indicated that the 5-FU levels of the tumors in small animals were significant higher for the 5-FU-MBs + US treatment than for either the 5-FU-MBs or 5-FU treatment with low 5-FU systemic treatment doses (2.5 mg/kg 5-FU IV). In small-animal treatment, 2.5 mg/kg 5-FU therapeutic IV doses injected into mice caused a more-significant reduction in tumor growth in the 5-FU-MBs + US group (65.9%) than in the control group after 34 days of treatment.

Crystal plane-integrated strontium oxide/hexagonal boron nitride nanohybrids for rapid electrochemical sensing of anticancer drugs in human blood serum samples

In this work, the crystal plane of strontium oxide (SrO) nanorods was integrated into hexagonal-boron nitride (h-BN) nanosheets to form 1D-2D (SrO/h-BN) composite were utilized for the electrochemical detection of the chemotherapeutic drug 5-fluorouracil (5-Fu). 5-Fu is a clinically proven and the third most frequently applied chemotherapeutic drug for treating solid tumours, such as colorectal, stomach, cutaneous and breast malignancies. Its overdoses lead to toxic metabolite accumulation that has serious adverse consequences on humans, including neurotoxicity, death and the induction of morbidity. Therefore, to improve the chemotherapy and predict the potential adverse effects of 5-Fu residues in the human body, susceptible and quick analytical methods for detecting 5-Fu in human body fluids (blood serum/plasma and urine) are needed. The effective interaction of the synthesized SrO/h-BN composite shows increased efficiency for the electrochemical detection of 5-Fu with good selectivity. Notably, a simple sonochemical method achieved a synergistic interaction between the (100) plane of SrO and the (002) plane of h-BN. Various analytical and spectroscopic techniques were used to characterize the SrO/h-BN nanocomposite, which provided useful insights into the composition and properties of the composite material. The crystalline, structural and chemical characteristics of the as-synthesized material were characterized by XRD, Raman spectroscopy, HR-TEM, XPS and HR-SEM. Furthermore, the proposed electrode's electrochemical sensing capability was analysed using CV, EIS, DPV and i-t curve methods. Numerous active sites created on a modified electrode enhanced the mass transport and electron transfer rate, thereby increasing the electrochemical activity towards the 5-Fu detection. Consequently, under optimized conditions, the SrO/h-BN/GCE exhibited remarkable selectivity, durability, low detection limit (0.003 μM) and wide linear range (0.02-56 μM) for 5-Fu. Finally, the successful application of this sensor for 5-Fu detection in biological samples was successfully tested with high recovery percentages.

A network pharmacology approach to investigate dehydrocostus lactone inhibits the proliferation and epithelial-mesenchymal transition of human gastric cancer cells via regulating the PI3K/Akt and extracellular signal-regulated kinases/mitogen-activated protein kinase signalling pathways

OBJECTIVES

Dehydrocostus lactone (DHE), a sesquiterpene lactone, has been proven the significant inhibition of multiple cancer cells. However, there are limited reports on the activity of DHE in gastric cancer (GC). In this research, Network pharmacology predicted the anti-GC mechanism of DHE, and the prediction was verified by in-vitro experiments.

METHODS

Network pharmacology confirmed the major effect signalling pathway of DHE in treating GC. Cell viability assay, colony formation assay, wound healing assay, cell migration and invasion assay, apoptosis assay, western blot and real-time quantitative polymerase chain reaction verified the mechanism of DHE in GC cell lines.

KEY FINDINGS

The results showed that DHE inhibited the growth and metastasis of MGC803 and AGS GC cells. Mechanistically, the analysis results indicated that DHE significantly induced the apoptosis process by suppressing the PI3K/protein kinase B (Akt) signalling pathway, and inhibited epithelial-mesenchymal transition by suppressing the extracellular signal-regulated kinases (ERK)/MAPK signalling pathway. The Akt activator (SC79) inhibited DHE induced apoptosis, and DHE had similar effects with the ERK inhibitor (FR180204).

CONCLUSIONS

All results suggested that DHE was a potential natural chemotherapeutic drug in GC treatment.

Response to the FDA Decision Regarding DPYD Testing Prior to Fluoropyrimidine Chemotherapy

Fluoropyrimidine (FP) chemotherapy is associated with severe, life-threatening toxicities, particularly among patients who carry deleterious germline variants in the DPYD gene. Pretreatment DPYD testing is standard of care throughout most of Europe; however, it has not been recommended in clinical practice guidelines in the United States. Due to increased risk of severe toxicity, a Citizen's Petition asked the US Food and Drug Administration (FDA) to update language in FP drug labels to recommend DPYD testing as part of a boxed warning and recommend FP dose reduction in patients carrying deleterious germline variants. In response, the FDA updated the capecitabine package insert to inform patients about the toxicity risk and test availability and consider DPYD testing. However, the FDA did not include a testing recommendation or requirement, or a boxed warning. Additionally, the FDA did not recommend FP dose adjustment in DPYD variant carriers. This review provides a critical assessment of the DPYD-FP pharmacogenetic association using the FDA's previously published Pharmacogenetic Pyramid, demonstrating that the evidence is compelling for recommending DPYD testing prior to FP treatment. Additionally, the FDA's stated concerns about recommending DPYD testing and DPYD-guided FP dose adjustment are addressed and discussed in the context of the FDA's other genetic testing and dose adjustment recommendations. We call on the FDA to follow our European counterparts in recommending DPYD testing and genotype-based dose adjustment to ensure patients with cancer receive safe and effective FP chemotherapy.

High molecular weight hyaluronic acid drastically reduces chemotherapy-induced mucositis and apoptotic cell death

Oral and intestinal mucositis (OIM) are debilitating inflammatory diseases initiated by oxidative stress, resulting in epithelial cell death and are frequently observed in cancer patients undergoing chemo-radiotherapy. There are currently few preventative strategies for this debilitating condition. Therefore, the development of a safe and effective mucositis mitigating strategy is an unmet medical need. Hyaluronic acid (HA) preparations have been tentatively used in oral mucositis. However, the protective effects of HA in chemotherapy-induced mucositis and their underlying mechanisms remain to be fully elucidated. This study aimed to assess these mechanisms using multiple formulations of enriched HA (Mucosamin^®), cross-linked (xl-), and non-crosslinked high molecular weight HA (H-MW-HA) in an oxidative stress-induced model of human oral mucosal injury in vitro and an in vivo murine model of 5-flurouracil (5-FU)-induced oral/intestinal mucositis. All tested HA formulations protected against oxidative stress-induced damage in vitro without inducing cytotoxicity, with H-MW-HA also significantly reducing ROS production. Daily supplementation with H-MW-HA in vivo drastically reduced the severity of 5-FU-induced OIM, prevented apoptotic damage and reduced COX-2 enzyme activity in both the oral and intestinal epithelium. In 5-FU-injected mice, HA supplementation also significantly reduced serum levels of IL-6 and the chemokine CXCL1/KC, while the serum antioxidant activity of superoxide dismutase was elevated. Our data suggest that H-MW-HA attenuates 5-FU-induced OIM, at least partly, by impeding apoptosis, inhibiting of oxidative stress and suppressing inflammatory cytokines. This study supports the development of H-MW-HA preparations for preventing OIM in patients receiving chemotherapy.

Cancer chemotherapy and beyond: Current status, drug candidates, associated risks and progress in targeted therapeutics

Cancer is an abnormal state of cells where they undergo uncontrolled proliferation and produce aggressive malignancies that causes millions of deaths every year. With the new understanding of the molecular mechanism(s) of disease progression, our knowledge about the disease is snowballing, leading to the evolution of many new therapeutic regimes and their successive trials. In the past few decades, various combinations of therapies have been proposed and are presently employed in the treatment of diverse cancers. Targeted drug therapy, immunotherapy, and personalized medicines are now largely being employed, which were not common a few years back. The field of cancer discoveries and therapeutics are evolving fast as cancer type-specific biomarkers are progressively being identified and several types of cancers are nowadays undergoing systematic therapies, extending patients' disease-free survival thereafter. Although growing evidence shows that a systematic and targeted approach could be the future of cancer medicine, chemotherapy remains a largely opted therapeutic option despite its known side effects on the patient's physical and psychological health. Chemotherapeutic agents/pharmaceuticals served a great purpose over the past few decades and have remained the frontline choice for advanced-stage malignancies where surgery and/or radiation therapy cannot be prescribed due to specific reasons. The present report succinctly reviews the existing and contemporary advancements in chemotherapy and assesses the status of the enrolled drugs/pharmaceuticals; it also comprehensively discusses the emerging role of specific/targeted therapeutic strategies that are presently being employed to achieve better clinical success/survival rate in cancer patients.

Pharmaceuticals Promoting Premature Termination Codon Readthrough: Progress in Development

Around 11% of all known gene lesions causing human genetic diseases are nonsense mutations that introduce a premature stop codon (PTC) into the protein-coding gene sequence. Drug-induced PTC readthrough is a promising therapeutic strategy for treating hereditary diseases caused by nonsense mutations. To date, it has been found that more than 50 small-molecular compounds can promote PTC readthrough, known as translational readthrough-inducing drugs (TRIDs), and can be divided into two major categories: aminoglycosides and non-aminoglycosides. This review summarizes the pharmacodynamics and clinical application potential of the main TRIDs discovered so far, especially some newly discovered TRIDs in the past decade. The discovery of these TRIDs brings hope for treating nonsense mutations in various genetic diseases. Further research is still needed to deeply understand the mechanism of eukaryotic cell termination and drug-induced PTC readthrough so that patients can achieve the greatest benefit from the various TRID treatments.

Electrochemiluminescence immunoassay strategies based on a hexagonal Ru-MOF and MoS2@GO nanosheets: detection of 5-fluorouracil in serum samples

Herein, a competitive-type electrochemiluminescence immunosensor for ultrasensitive detection of 5-fluorouracil (5-FU) was fabricated. Ruthenium(II)-metal-organic framework (Ru-MOF) nanosheets were selected to act a promising ECL luminophore using tris(4,4'-dicarboxylic acid-2,2'-bipyridyl) ruthenium(II) dichloride (Ru(dcbpy)₃²⁺) as the organic ligand. The two-dimensional (2D) Ru-MOF nanosheets achieved an increased loading of Ru(dcbpy)₃²⁺ and effectively prevented leakage of the ECL emitter during application, which exhibited satisfactory ECL performance. Thin two-dimensional MoS₂@GO was used to modify the electrode as the sensing platform for improving the electron transfer rate and loading more 5-FU coating antigens due to its large specific surface area and piezoelectric catalytic efficiency. Under the optimized conditions, the proposed immunosensor presented high sensitivity, a wide detection range (0.0001 ng-100 ng mL^-1), a low limit of detection (0.031 pg mL^-1, S/N = 3), good specificity and stability. Furthermore, the immunosensor was successfully applied for the detection of 5-FU in human serum samples with satisfactory results, proving this strategy has potential applications in bioanalysis and clinical diagnosis.

Precision fluoropyrimidines dosing in a compound heterozygous variant carrier of the DPYD gene: a case report

BACKGROUND

Fluoropyrimidines (FPs) form still nowadays the backbone of chemotherapic schemes in colorectal cancer (CRC). Inter-patient variability of the toxicity profile of FPs may be partially accounted for by variable expression of dihydropyrimidine dehydrogenase (DPD). DPD rate activity is genetically determined by its extremely polymorphic coding gene DPYD. In spite of pharmacogenetic guideline-directed-dosing of FPs based regimens treating carrier of multiple variants of DPYD gene remains still challenging.

CASE PRESENTATION

We present a case of a 48-year-old Caucasian man, compound heterozygous variant carrier of the DPYD gene (HapB3 and c.2194G>A) who had a diagnosis of adenocarcinoma of the left colon and was safely treated with a pharmacogenetic-guided 25% dose reduction of the standard CAP adjuvant treatment. Compound heterozygosis may have been responsible for an earlier over exposure to CAP resulting into low-grade toxicity with an anticipated median time to toxicity of the c.2194G>A variant to the 4th vs. 6th cycles. Some haplotypes of DPYD variants may have an advantage in terms of survival compared to wild-type patients. Our patient may also have benefitted from compound heterozygosis, as shown by no evidence of disease (NED) at 6-month follow-up.

CONCLUSION

Pharmacogenetic-guided dosing of DPYD intermediate metabolizer compound heterozygous HapB3 and c.2194G>A variant carries should be managed by a multidisciplinary team with a dose reduction ranging from 25 to 50% to maintain effectiveness and close clinical monitoring for early detection of ADRs.

Is the combination of immunotherapy with conventional chemotherapy the key to increase the efficacy of colorectal cancer treatment?

Colorectal cancer (CRC) is among the most prevalent and deadly neoplasms worldwide. According to GLOBOCAN predictions, its incidence will increase from 1.15 million CRC cases in 2020 to 1.92 million cases in 2040. Therefore, a better understanding of the mechanisms involved in CRC development is necessary to improve strategies focused on reducing the incidence, prevalence, and mortality of this oncological pathology. Surgery, chemotherapy, and radiotherapy are the main strategies for treating CRC. The conventional chemotherapeutic agent utilized throughout the last four decades is 5-fluorouracil, notwithstanding its low efficiency as a single therapy. In contrast, combining 5-fluorouracil therapy with leucovorin and oxaliplatin or irinotecan increases its efficiency. However, these treatments have limited and temporary solutions and aggressive side effects. Additionally, most patients treated with these regimens develop drug resistance, which leads to disease progression. The immune response is considered a hallmark of cancer; thus, the use of new strategies and methodologies involving immune molecules, cells, and transcription factors has been suggested for CRC patients diagnosed in stages III and IV. Despite the critical advances in immunotherapy, the development and impact of immune checkpoint inhibitors on CRC is still under investigation because less than 25% of CRC patients display an increased 5-year survival. The causes of CRC are diverse and include modifiable environmental factors (smoking, diet, obesity, and alcoholism), individual genetic mutations, and inflammation-associated bowel diseases. Due to these diverse causes, the solutions likely cannot be generalized. Interestingly, new strategies, such as single-cell multiomics, proteomics, genomics, flow cytometry, and massive sequencing for tumor microenvironment analysis, are beginning to clarify the way forward. Thus, the individual mechanisms involved in developing the CRC microenvironment, their causes, and their consequences need to be understood from a genetic and immunological perspective. This review highlighted the importance of altering the immune response in CRC. It focused on drugs that may modulate the immune response and show specific efficacy and contrasted with evidence that immunosuppression or the promotion of the immune response is the answer to generating effective treatments with combined chemotherapeutic drugs.

Characterization of a novel dual murine model of chemotherapy-induced oral and intestinal mucositis

Oral and intestinal mucositis are debilitating inflammatory diseases observed in cancer patients undergoing chemo-radiotherapy. These are devastating clinical conditions which often lead to treatment disruption affecting underlying malignancy management. Although alimentary tract mucositis involves the entire gastrointestinal tract, oral and intestinal mucositis are often studied independently utilizing distinct organ-specific pre-clinical models. This approach has however hindered the development of potentially effective whole-patient treatment strategies. We now characterize a murine model of alimentary tract mucositis using 5-Fluorouracil (5-FU). Mice were given 5-FU intravenously (50 mg/kg) or saline every 48 h for 2 weeks. Post initial injection, mice were monitored clinically for weight loss and diarrhea. The incidence and extent of oral mucositis was assessed macroscopically. Microscopical and histomorphometric analyses of the tongue and intestinal tissues were conducted at 3 interim time points during the experimental period. Repeated 5-FU treatment caused severe oral and intestinal atrophy, including morphological damage, accompanied by body weight loss and mild to moderate diarrhea in up to 77.8% of mice. Oral mucositis was clinically evident throughout the observation period in 88.98% of mice. Toluidine blue staining of the tongue revealed that the ulcer size peaked at day-14. In summary, we have developed a model reproducing the clinical and histologic features of both oral and intestinal mucositis, which may represent a useful in vivo pre-clinical model for the study of chemotherapy-induced alimentary tract mucositis and the development of preventative therapies.

Advanced prodrug strategies in nucleoside analogues targeting the treatment of gastrointestinal malignancies

Gastrointestinal malignancies are common digestive system tumor worldwide. Nucleoside analogues have been widely used as anticancer drugs for the treatment of a variety of conditions, including gastrointestinal malignancies. However, low permeability, enzymatic deamination, inefficiently phosphorylation, the emergence of chemoresistance and some other issues have limited its efficacy. The prodrug strategies have been widely applied in drug design to improve pharmacokinetic properties and address safety and drug-resistance issues. This review will provide an overview of the recent developments of prodrug strategies in nucleoside analogues for the treatment of gastrointestinal malignancies.

Oligonucleotides Carrying Nucleoside Antimetabolites as Potential Prodrugs

BACKGROUND

Nucleoside and nucleobase antimetabolites are an important class of chemotherapeutic agents for the treatment of cancer as well as other diseases.

INTRODUCTION

In order to avoid undesirable side effects, several prodrug strategies have been developed. In the present review, we describe a relatively unknown strategy that consists of using oligonucleotides modified with nucleoside antimetabolites as prodrugs.

METHODS

The active nucleotides are generated by enzymatic degradation once incorporated into cells. This strategy has attracted large interest and is widely utilized at present due to the continuous developments made in therapeutic oligonucleotides and the recent advances in nanomaterials and nanomedicine.

RESULTS

A large research effort was made mainly in the improvement of the antiproliferative properties of nucleoside homopolymers, but recently, chemically modified aptamers, antisense oligonucleotides and/or siRNA carrying antiproliferative nucleotides have demonstrated a great potential due to the synergetic effect of both therapeutic entities. In addition, DNA nanostructures with interesting properties have been built to combine antimetabolites and enhancers of cellular uptake in the same scaffold. Finally, protein nanoparticles functionalized with receptor-binders and antiproliferative oligomers represent a new avenue for a more effective treatment in cancer therapy.

CONCLUSION

It is expected that oligonucleotides carrying nucleoside antimetabolites will be considered as potential drugs in the near future for biomedical applications.

When Two Maladies Meet: Disease Burden and Pathophysiology of Stroke in Cancer

Stroke and cancer are disabling diseases with an enormous global burden, disproportionately affecting vulnerable populations and low- and middle-income countries. Both these diseases share common risk factors, which warrant concerted attention toward reshaping population health approaches and the conducting of fundamental studies. In this article, an overview of epidemiological trends in the prevalence and burden of cancer and stroke, underlying biological mechanisms and clinical risk factors, and various tools available for risk prediction and prognosis are provided. Finally, future recommendations for research and existing gaps in our understanding of pathophysiology. Further research must investigate the causes that predispose patients to an increased risk of stroke and/or cancer, as well as biomarkers that can be used to predict growing morbidity and mortality.

Translational readthrough of nonsense mutant TP53 by mRNA incorporation of 5-Fluorouridine

TP53 nonsense mutations in cancer produce truncated inactive p53 protein. We show that 5-FU metabolite 5-Fluorouridine (FUr) induces full-length p53 in human tumor cells carrying R213X nonsense mutant TP53. Ribosome profiling visualized translational readthrough at the R213X premature stop codon and demonstrated that FUr-induced readthrough is less permissive for canonical stop codon readthrough compared to aminoglycoside G418. FUr is incorporated into mRNA and can potentially base-pair with guanine, allowing insertion of Arg tRNA at the TP53 R213X UGA premature stop codon and translation of full-length wild-type p53. We confirmed that full-length p53 rescued by FUr triggers tumor cell death by apoptosis. FUr also restored full-length p53 in TP53 R213X mutant human tumor xenografts in vivo. Thus, we demonstrate a novel strategy for therapeutic rescue of nonsense mutant TP53 and suggest that FUr should be explored for treatment of patients with TP53 nonsense mutant tumors.

Assessment of the Clinical Utility of Pretreatment DPYD Testing for Patients Receiving Fluoropyrimidine Chemotherapy

PURPOSE

Patients who carry pathogenic variants in DPYD have higher systemic fluoropyrimidine (FP) concentrations and greater risk of severe and fatal FP toxicity. Pretreatment DPYD testing and DPYD-guided FP dosing to reduce toxicity and health care costs is recommended by European clinical oncology guidelines and has been adopted across Europe, but has not been recommended or adopted in the United States. The cochairs of the National Comprehensive Cancer Network Guidelines for colon cancer treatment explained their concerns with recommending pretreatment DPYD testing, particularly the risk that reduced FP doses in DPYD carriers may reduce treatment efficacy.

METHODS

This special article uses previously published frameworks for assessing the clinical utility of cancer biomarker tests, including for germline indicators of toxicity risk, to assess the clinical utility of pretreatment DPYD testing, with a particular focus on the risk of reducing treatment efficacy.

RESULTS

There is no direct evidence of efficacy reduction, and the available indirect evidence demonstrates that DPYD-guided FP dosing results in similar systemic FP exposure and toxicity compared with standard dosing in noncarriers, and is well calibrated to the maximum tolerated dose, strongly suggesting there is minimal risk of efficacy reduction.

CONCLUSION

This article should serve as a call to action for clinicians and clinical guidelines committees in the United States to re-evaluate the clinical utility of pretreatment DPYD testing. If clinical utility has not been demonstrated, further dialogue is needed to clarify what additional evidence is needed and which of the available study designs, also described within this article, would be appropriate. Clinical guideline recommendations for pretreatment DPYD testing would increase clinical adoption and ensure that all patients receive maximally safe and effective FP treatment.

Case report: Acute toxic myocardial damage caused by 5-fluorouracil—from enigma to success

Considering the pandemic of both cardiovascular diseases and oncological diseases, there is an increasing need for the use of chemotherapy, which through various pathophysiological mechanisms leads to damage to heart function. Cardio toxicity of chemotherapy drugs can manifest itself in a variety of clinical manifestations, which is why establishing a valid diagnosis is a real mystery for clinicians. Acute systolic heart failure (AHF) due to the use of 5-fluorouracil (5-FU) is a rare occurrence if it is not associated with myocardial infarction, myocarditis or Takotsubo cardiomyopathy. Therefore, we decided to present a case of an 52-year-old male who was diagnosed with stage IV RAS wild-type adenocarcinoma of the rectum and in whom the direct toxic effect 5-FU is the main reason for the appearance of toxic cardiomyopathy.

Sensitization of Patient-Derived Colorectal Cancer Organoids to Photon and Proton Radiation by Targeting DNA Damage Response Mechanisms

Pathological complete response (pCR) has been correlated with overall survival in several cancer entities including colorectal cancer. Novel total neoadjuvant treatment (TNT) in rectal cancer has achieved pathological complete response in one-third of the patients. To define better treatment options for nonresponding patients, we used patient-derived organoids (PDOs) as avatars of the patient's tumor to apply both photon- and proton-based irradiation as well as single and combined chemo(radio)therapeutic treatments. While response to photon and proton therapy was similar, PDOs revealed heterogeneous responses to irradiation and different chemotherapeutic drugs. Radiotherapeutic response of the PDOs was significantly correlated with their ability to repair irradiation-induced DNA damage. The classical combination of 5-FU and irradiation could not sensitize radioresistant tumor cells. Ataxia-telangiectasia mutated (ATM) kinase was activated upon radiation, and by inhibition of this central sensor of DNA damage, radioresistant PDOs were resensitized. The study underlined the capability of PDOs to define nonresponders to irradiation and could delineate therapeutic approaches for radioresistant patients.

In Vitro Antioxidant and Pancreatic Anticancer Activity of Novel 5-Fluorouracil-Coumarin Conjugates

Molecular hybridization consists of the combination of two or more non-identical pharmacophores in a single molecule. It has emerged as a promising strategy that allows the design of molecular frameworks with enhanced activity and affinity compared to their parent drugs. In this work, two novel hybrids that combine the well-known anticancer chemotherapeutic agent 5-fluorouracil with antioxidant coumarin derivatives have been synthesized and characterized by means of a copper-catalyzed azide-alkyne cycloaddition (CuAAC). The conjugates showed good antioxidant properties and a high tendency to aggregate and form stable nanoparticles in aqueous media, with regular shape and uniform size. These materials have proven to be preferential cytotoxic agents in vitro against human pancreatic cancer cells PANC-1, with an activity superior to free 5-fluorouracil. These results open up the possibility of exploiting the synergistic combination between 5-fluorouracil and coumarin derivatives and warrant further investigation of these hybrids as promising pancreatic anticancer agents.

Protective Effects of Alpha-Lipoic Acid against 5-Fluorouracil-Induced Gastrointestinal Mucositis in Rats

Alpha-lipoic acid (ALA) is extensively utilized in multivitamin formulas and anti-aging products. The purpose of this study was to investigate the potential protective benefits of ALA on 5-fluorouracil (5-FU)-induced gastrointestinal mucositis in Wistar albino rats. Tissues from the stomach, small intestine, and large intestine were excised, and blood sera were obtained to identify biochemical indices such as TNF-α, IL-1β, MDA, GPx, SOD, MMP-1, -2, -8, and TIMP-1. A histopathological study was also performed. The results revealed mucositis-elevated TNF-, IL-1, MDA, MMP-1, -2, -8, and TIMP-1 levels in both tissues and sera, and these values dropped dramatically following ALA treatment. Reduced SOD and GPx activities in mucositis groups were reversed in ALA-treated groups. The damage produced by mucositis in the stomach and small intestine regressed in the ALA-treated group, according to histopathological evaluation. Consequently, the implementation of ALA supplementation in 5-FU therapy may act as a protective intervention for cancer patients with gastrointestinal mucositis. In light of the findings, ALA, a food-derived antioxidant with pleiotropic properties, may be an effective treatment for 5-FU-induced gastrointestinal mucositus, and prevent oxidative stress, inflammation, and tissue damage in cancer patients receiving 5-FU therapy.

Combination of 5-Fluorouracil with Photodynamic Therapy: Enhancement of Innate and Adaptive Immune Responses in a Murine Model of Actinic Keratosis

We previously showed that a combination of differentiation-inducing agents (5-fluorouracil, vitamin D3, or methotrexate) and aminolevulinate-based photodynamic therapy (PDT) improves clinical responses by enhancing protoporphyrin IX (PpIX) photosensitizer levels and cell death. Here, we show that in addition to its previously known effects, 5-fluorouracil (5FU) enhances PDT-induced tumor-regressing immunity. Murine actinic keratoses (AK) were treated with topical 5FU or vehicle for three days prior to ALA application, followed by blue light illumination (~417 nm). Lesions were harvested for time-course analyses of innate immune cell recruitment into lesions, i.e., neutrophils (Ly6G+) and macrophages (F4/80+), which peaked at 72 hours and 1 week post PDT, respectively, and was greater in 5FU treated lesions. Enhanced infiltration of activated T cells (CD3+) throughout the time course, and of cytotoxic T cells (CD8+) at 1 - 2 weeks post PDT, also occurred in 5FU treated lesions. 5FU pretreatment reduced the presence of cells expressing the immune checkpoint marker PD-1 at ~72 hours post PDT, favoring cytotoxic T cell activity. A combination of 5FU and PDT, each individually known to induce long-term tumor-targeting immune responses in addition to their more immediate effects on cancer cells, may synergize to provide better management of squamous precancers.

Electron attachment to fluorodeoxyglucose: Dissociation dynamics in a molecule of near-zero electron affinity

Fluorodeoxyglucose (FDG) is a glucose derivative with fluorine at the C₂ position. The molecule containing the radioactive F-18 isotope is well known from its application in positron emission tomography as a radiotracer in tumor examination. In the stable form with the F-19 isotope, FDG was proposed as a potential radiosensitizer. Since reduction processes may be relevant in radiosensitization, we investigated low-energy electron attachment to FDG with a crossed electron-molecule beam experiment and with quantum chemical calculations as well as molecular dynamics at elevated temperatures to reveal statistical dissociation. We experimentally find that the susceptibility of FDG to low-energy electrons is relatively low. The calculations indicate that upon attachment of an electron with a kinetic energy of ∼0 eV, only dipole-bound states are accessible, which agrees with the weak ion yields observed in the experiment. The temporary negative ions formed upon electron attachment to FDG may decay by a large variety of dissociation reactions. The major fragmentation channels include H₂O, HF, and H₂ dissociation, accompanied by ring opening.

Diagnosis and management of 5-fluorouracil (5-FU)-induced acute leukoencephalopathy: lessons learnt from a single-Centre case series

Background

The administration of 5-fluorouracil (5FU) in the treatment of gastrointestinal (GI) malignancies is associated with common side effects such as mucositis, diarrhoea, and myelosuppression, which are easily managed with supportive measures and dose adjustments. Cardiotoxicity and neurotoxicity are rare but reversible side effects of 5-FU and are treated with withdrawal of the drug and conservative measures. The presenting symptoms of 5-FU-induced leukoencephalopathy are often confusing and pose a diagnostic dilemma in routine clinical practice.

Methods

We report a series of five patients with GI malignancies who developed 5-FU-induced leukoencephalopathy.

Results

All (n = 5) had Naranjo scores of 6–7, predictive of 5-FU-related adverse effects, with clinical and radiological findings suggestive of 5-FU-induced encephalopathy as described in prior literature. The median time to onset of symptoms from initiation of 5FU was 3 days (range: 2–4 days). All patients improved after conservative management with complete neurological recovery.

Conclusion

Prompt recognition of this rare yet severe adverse effect of 5-FU-based chemotherapy aids early withdrawal of the offending agent (5-FU) and timely initiation of supportive measures and helps plan alternative oncological interventions.

A novel thermosensitive poloxamer-hyaluronic acid- kappa-carrageenan-based hydrogel anti-adhesive agent loaded with 5-fluorouracil: a preclinical study in Sprague-Dawley rats

Although the first-choice treatment for colorectal cancer is cytoreductive surgery combined with chemotherapy, post-surgical peritoneal adhesion and extant malignancy can cause fatal complications. Studies examining hydrogel-based postoperative anti-adhesion treatments are still limited. In this study, several formulations of 5-fluorouracil (5-FU) loaded into hyaluronic acid (HA) and kappa-carrageenan (kCGN)-poloxamer 407 (P407)-based cross-linked hydrogels were prepared and evaluated in vitro and in vivo for their efficacy in preventing adhesion. These hydrogels met a set of desired specifications such as thermosensitive behavior, strong elasticity at body temperature (tan δ < 1.0 at 37°C), and ability to encapsulate hydrophilic drug and deliver it in a sustained released manner. Our secondary purpose is to provide in situ 5-FU for additional local antitumor effect when the anti-adhesion agent is spread over the tumor site. Over 60% of the total loaded drug was released within 4 hours, and about 80% of 5-FU was released after three days. Both the Higuchi and Korsmeyer-Peppas models showed that the mechanism of sustained drug release involved diffusion. The constructed hydrogels were evaluated for in vivo intra-abdominal anti-adhesion barrier efficiency; the HA/kCGN 1%/3% w/v hydrogel formulation showed the best anti-adhesion effect in this preclinical study using Sprague-Dawley rat models.

CETSA interaction proteomics define specific RNA-modification pathways as key components of fluorouracil-based cancer drug cytotoxicity

The optimal use of many cancer drugs is hampered by a lack of detailed understanding of their mechanism of action (MoA). Here, we apply a high-resolution implementation of the proteome-wide cellular thermal shift assay (CETSA) to follow protein interaction changes induced by the antimetabolite 5-fluorouracil (5-FU) and related nucleosides. We confirm anticipated effects on the known main target, thymidylate synthase (TYMS), and enzymes in pyrimidine metabolism and DNA damage pathways. However, most interaction changes we see are for proteins previously not associated with the MoA of 5-FU, including wide-ranging effects on RNA-modification and -processing pathways. Attenuated responses of specific proteins in a resistant cell model identify key components of the 5-FU MoA, where intriguingly the abrogation of TYMS inhibition is not required for cell proliferation.

DNA-Damage-Response-Targeting Mitochondria-Activated Multifunctional Prodrug Strategy for Self-Defensive Tumor Therapy

We report a novel multifunctional construct, M1, designed explicitly to target the DNA damage response in cancer cells. M1 contains both a floxuridine (FUDR) and protein phosphatase 2A (PP2A) inhibitor combined with a GSH-sensitive linker. Further conjugation of the triphenylphosphonium moiety allows M1 to undergo specific activation in the mitochondria, where mitochondria-mediated apoptosis is observed. Moreover, M1 has enormous effects on genomic DNA ascribed to FUDR's primary function of impeding DNA/RNA synthesis combined with diminishing PP2A-activated DNA repair pathways. Importantly, mechanistic studies highlight the PP2A obtrusion in FUDR/5-fluorouracil (5-FU) therapy and underscore the importance of its inhibition to harbor therapeutic potential. HCT116 cell xenograft-bearing mice that have a low response rate to 5-FU show a prominent effect with M1, emphasizing the importance of DNA damage response targeting strategies using tumor-specific microenvironment-activatable systems.

Discovery of a potent cytotoxic agent that promotes G2/M phase cell cycle arrest and apoptosis in a malignant human pharyngeal squamous carcinoma cell line

Squamous cell carcinoma is the major form of malignancy that arises in head and neck cancer. The modest improvement in the 5‑year survival rate underpins its complex etiology and provides the impetus for the discovery of new therapeutics. The present study describes the discovery of an indole‑based small molecule (24a) that was a potent cytotoxic agent with antiproliferative and pro‑apoptotic properties against a pharyngeal carcinoma cell line, Detroit 562, effectively killing the cells at a half‑maximal inhibitory concentration of 0.03 µM, as demonstrated using cell proliferation studies. The antiproliferative property of 24a was demonstrated by its ability to promote G₂/M blockade, as assessed by cell cycle analysis using flow cytometry and the monitoring of real‑time cell cycle progression by the fluorescence ubiquitination‑based cell cycle indicator. This pro‑apoptotic property is supported by the promotion of TUNEL‑staining and increase in the activities of caspases‑3/7 and ‑6, in addition to the expression of death receptors and the cleavage of poly (ADP‑ribose) polymerase 1 protein as demonstrated by western blotting. Given that Detroit 562 lacks functional p53, it is suggested that 24a acts independently of the tumor suppressor.

Somatic nuclear auto-antigenic sperm protein sensitizes human breast cancer cells to 5-Fluorouracil

PURPOSE

To assess the potential role of nuclear auto-antigenic sperm protein (NASP) in the cellular sensitivity to 5-Fluorouracil (5-FU) in breast cancer cells.

METHODS

The expression of two NASP isotypes, namely somatic NASP (sNASP) and testis NASP (tNASP) in breast cancer lines were detected under 5-FU treatment using real-time polymerase chain reaction and western blot assays. NASP effect on cellular viability and apoptosis under 5-FU treatment were evaluated. The interaction between NASP and its downstream proteins were evaluated using the co-immunoprecipitation (Co-IP) assays.

RESULTS

5-FU significantly decreased the mRNA and protein expression levels of sNASP. Inhibition of sNASP increased cellular viability, colony formation ability, but reduced apoptosis in tested cell lines in response to 5-FU, which were reversed by sNASP over-expression. Further study reveals 5-FU disrupts sNASP/TNF receptor-associated factor 6 (TRAF6) complex, potentiates cellular sensitivity to 5-FU via NK-kB.

CONCLUSION

Our findings suggest sNASP is a novel molecular target having potential to overcome the resistance to 5-FU in breast cancer cells.

Myricetin (3,3',4',5,5',7-Hexahydroxyflavone) Prevents 5-Fluorouracil-Induced Cardiotoxicity

5-Fluorouracil (5-FU) is a strong anti-cancer drug used to manage numerous cancers. Cardiotoxicity, renal toxicity, and liver toxicity are some of the adverse effects which confine its clinical use to some extent. 5-FU-induced organ injuries are associated with redox imbalance, inflammation, and damage to heart functioning, particularly in the present study. Myricetin is an abundant flavonoid, commonly extracted from berries and herbs having anti-oxidative and anti-cancer activities. We planned the current work to explore the beneficial effects of myricetin against 5-FU-induced cardiac injury in Wistar rats through a biochemical and histological approach. Prophylactic myricetin treatment at two doses (25 and 50 mg/kg) was given to rats orally for 21 days against cardiac injury induced by a single injection of 5-FU (150 mg/kg b.wt.) given on the 20th day intraperitoneally. The 5-FU injection induced oxidative stress, inflammation, and extensive cardiac damage. Nevertheless, myricetin alleviated markers of inflammation, apoptosis, cardiac toxicity, oxidative stress, and upregulated anti-oxidative machinery. The histology of heart further supports our biochemical findings mitigated by the prophylactic treatment of myricetin. Henceforth, myricetin mitigates 5-FU-induced cardiac damage by modulating oxidative stress, inflammation, and cardiac-specific markers, as found in the present study.

Molecular mechanisms associated with chemoresistance in esophageal cancer

Esophageal cancer (EC) is one of the most incident and lethal tumors worldwide. Although surgical resection is an important approach in EC treatment, late diagnosis, metastasis and recurrence after surgery have led to the management of adjuvant and neoadjuvant therapies over the past few decades. In this scenario, 5-fluorouracil (5-FU) and cisplatin (CISP), and more recently paclitaxel (PTX) and carboplatin (CBP), have been traditionally used in EC treatment. However, chemoresistance to these agents along EC therapeutic management represents the main obstacle to successfully treat this malignancy. In this sense, despite the fact that most of chemotherapy drugs were discovered several decades ago, in many cases, including EC, they still represent the most affordable and widely employed treatment approach for these tumors. Therefore, this review summarizes the main mechanisms through which the response to the most widely chemotherapeutic agents used in EC treatment is impaired, such as drug metabolism, apoptosis resistance, cancer stem cells (CSCs), cell cycle, autophagy, energetic metabolism deregulation, tumor microenvironment and epigenetic modifications.

pH-Sensitive nanoparticles containing 5-fluorouracil and leucovorin as an improved anti-cancer option for colon cancer

Background: Parenteral administration of chemotherapeutic drugs, 5-fluorouracil (5-FU) and leucovorin (LV), is commonly used to treat large bowel carcinomas such as colon cancer (CC) and colorectal carcinoma (CRC). Aim: Our study aims to design a novel nanoparticulate drug-delivery vehicle for oral use capable of colon-specific release. Methods: A modified double-emulsion solvent evaporation method was used in the preparation of pH-responsive Eudargit^® S100 polymeric nanoparticles, loaded with 5-FU/LV combination (5-FU/LV-loaded Eudargit S100 NPs). Results: Our optimized drug-loaded NP showed a pH-responsive drug release and exhibited significantly more cytotoxic actions in cancer-cell lines than free drugs. Conclusion: These findings open the way for conducting clinical trials for colon malignancies treated with nanoparticles.

Risk for Myocardial Infarction Following 5-Fluorouracil Treatment in Patients With Gastrointestinal Cancer

Background

Myocardial infarction is a cardiac adverse event associated with 5-fluorouracil (5-FU). There are limited data on the incidence, risk, and prognosis of 5-FU-associated myocardial infarction.

Objectives

The aim of this study was to examine the risk for myocardial infarction in patients with gastrointestinal (GI) cancer treated with 5-FU compared with age- and sex-matched population control subjects without cancer (1:2 ratio).

Methods

Patients with GI cancer treated with 5-FU between 2004 and 2016 were identified within the Danish National Patient Registry. Prevalent ischemic heart disease in both groups was excluded. Cumulative incidences were calculated, and multivariable regression and competing risk analyses were performed.

Results

A total of 30,870 patients were included in the final analysis, of whom 10,290 had GI cancer and were treated with 5-FU and 20,580 were population control subjects without cancer. Differences in comorbid conditions and select antianginal medications were nonsignificant (P > 0.05 for all). The 6-month cumulative incidence of myocardial infarction was significantly higher for 5-FU patients at 0.7% (95% CI: 0.5%-0.9%) versus 0.3% (95% CI: 0.3%-0.4%) in population control subjects, with a competing risk for death of 12.1% versus 0.6%. The 1-year cumulative incidence of myocardial infarction for 5-FU patients was 0.9% (95% CI: 0.7%-1.0%) versus 0.6% (95% CI: 0.5%-0.7%) among population control subjects, with a competing risk for death of 26.5% versus 1.4%. When accounting for competing risks, the corresponding subdistribution hazard ratios suggested an increased risk for myocardial infarction in 5-FU patients, compared with control subjects, at both 6 months (hazard ratio: 2.10; 95% CI: 1.50-2.95; P < 0.001) and 12 months (hazard ratio: 1.39; 95% CI: 1.05-1.84; P = 0.022).

Conclusions

Despite a statistically significantly higher 6- and 12-month risk for myocardial infarction among 5-FU patients compared with population control subjects, the absolute risk for myocardial infarction was low, and the clinical significance of these differences appears to be limited in the context of the significant competing risk for death in this population.

Cardiotoxicity of Fluoropyrimidines: Epidemiology, Mechanisms, Diagnosis, and Management

Cancer is a growing public health problem; it is responsible annually for millions of deaths worldwide. Fluoropyrimidines are highly effective and commonly prescribed anti-neoplastic drugs used in a wide range of chemotherapy regimens against several types of malignancies. 5-fluorouracil and its prodrugs affect neoplastic cells in multiple ways by impairing their proliferation, principally through the inhibition of thymidylate synthase. Fluoropyrimidine-induced cardiotoxicity was described more than 50 years ago, but many details such as incidence, mechanisms, and treatment are unclear and remain disputed. Severe cardiotoxicity is not only life-threatening, but also leads to withdrawal from an optimal chemotherapy regimen and decreases survival rate. Differences in the frequency of cardiotoxicity are explained by different chemotherapy schedules, doses, criteria, and populations. Proposed pathophysiological mechanisms include coronary vasospasm, endothelial damage, oxidative stress, Krebs cycle disturbances, and toxic metabolites. Such varied pathophysiology of the cardiotoxicity phenomenon makes prevention and treatment more difficult. Cardiovascular disturbances, including chest pain, arrhythmias, and myocardial infarction, are among the most common side effects of this class of anti-neoplastic medication. This study aims to summarize the available data on fluoropyrimidine cardiotoxicity with respect to symptoms, incidence, metabolism, pathophysiological mechanism, diagnosis, management, and resistance.