5-FU therapeutic drug monitoring as a valuable option to reduce toxicity in patients with gastrointestinal cancer

The combination of SHP099 inhibits the malignant biological behavior of L-OHP/5-FU-resistant colorectal cancer cells by regulating energy metabolism reprogramming

BACKGROUND AND OBJECTIVE

Colorectal cancer (CRC) is one of the most common malignancies in China. At present, there is a problem that the CRC treatment drugs SHP099, L-OHP and 5-FU are insensitive to tumor cells. Combination medication is an important means to solve the insensitivity of medication alone. The purpose of this project was to explore the effect and molecular mechanism of SHP099 combination on the malignant biological behavior of L-OHP/5-FU resistant strains of CRC.

METHODS

HT29 and SW480 cells were cultured in media supplemented with L-OHP or 5-FU to establish drug-resistant strains. HT29 and SW480 drug-resistant cells were subcutaneously injected into the ventral nerves of nude mice at a dose of 5 × 106 to establish CRC drug-resistant animal models. CCK-8, Western blot, flow cytometry, Transwell and kit detection were used to detect the regulatory mechanism of energy metabolism reprogramming in drug-resistant CRC cells.

RESULTS

Compared with nonresistant strains, L-OHP/5-FU-resistant strains exhibited greater metabolic reprogramming. Functionally, SHP099 can restrain the metabolic reprogramming of L-OHP/5-FU-resistant strains and subsequently restrain the proliferation, colony formation, migration and spheroid formation of L-OHP/5-FU-resistant strains. Downstream mechanistic studies have shown that SHP099 interferes with the metabolic reprogramming of L-OHP/5-FU drug-resistant strains by suppressing the PI3K/AKT pathway, thereby restraining the malignant biological behavior of L-OHP/5-FU drug-resistant strains and alleviating CRC.

CONCLUSION

The combination of SHP099 can restrain the malignant biological behavior of L-OHP/5-FU-resistant CRC cells and alleviate the progression of CRC by interfering with the reprogramming of energy metabolism. This study explored the effect of SHP099 combination on dual-resistant CRC cells for the first time, and provided a new therapeutic idea for solving the problem of SHP099 insensitivity to CRC cells.

Review of Prodrug and Nanodelivery Strategies to Improve the Treatment of Colorectal Cancer with Fluoropyrimidine Drugs

Fluoropyrimidine (FP) drugs are central components of combination chemotherapy regimens for the treatment of colorectal cancer (CRC). FP-based chemotherapy has improved survival outcomes over the last several decades with much of the therapeutic benefit derived from the optimization of dose and delivery. To provide further advances in therapeutic efficacy, next-generation prodrugs and nanodelivery systems for FPs are being developed. This review focuses on recent innovative nanodelivery approaches for FP drugs that display therapeutic promise. We summarize established, clinically useful FP prodrug strategies, including capecitabine, which exploit tumor-specific enzyme expression for optimal anticancer activity. We then describe the use of FP DNA-based polymers (e.g., CF10) for the delivery of activated FP nucleotides as a nanodelivery approach with proven activity in pre-clinical models and with clinical potential. Multiple nanodelivery systems for FP delivery show promise in CRC pre-clinical models and we review advances in albumin-mediated FP delivery, the development of mesoporous silica nanoparticles, emulsion-based nanoparticles, metal nanoparticles, hydrogel-based delivery, and liposomes and lipid nanoparticles that display particular promise for therapeutic development. Nanodelivery of FPs is anticipated to impact CRC treatment in the coming years and to improve survival for cancer patients.

The cross talk of ubiquitination and chemotherapy tolerance in colorectal cancer

Ubiquitination, a highly adaptable post-translational modification, plays a pivotal role in maintaining cellular protein homeostasis, encompassing cancer chemoresistance-associated proteins. Recent findings have indicated a potential correlation between perturbations in the ubiquitination process and the emergence of drug resistance in CRC cancer. Consequently, numerous studies have spurred the advancement of compounds specifically designed to target ubiquitinates, offering promising prospects for cancer therapy. In this review, we highlight the role of ubiquitination enzymes associated with chemoresistance to chemotherapy via the Wnt/β-catenin signaling pathway, epithelial-mesenchymal transition (EMT), and cell cycle perturbation. In addition, we summarize the application and role of small compounds that target ubiquitination enzymes for CRC treatment, along with the significance of targeting ubiquitination enzymes as potential cancer therapies.

Nerolidol, Bioactive Compound Suppress Growth of HCT-116 Colorectal Cancer Cells Through Cell Cycle Arrest and Induction of Apoptosis

Colon cancer is the most prevalent cancer and causes the highest cancer-associated mortality in both men and women globally. It has a high incidence and fatality rate, which places a significant burden on the healthcare system. The current work was performed to understand the beneficial roles of nerolidol on the viability and cytotoxic mechanisms in the colon cancer HCT-116 cells. The MTT cytotoxicity assay was done to investigate the effect of nerolidol at different doses (5-100 µM) on the HCT-116 cell viability. The impacts of nerolidol on ROS accumulation and apoptosis were investigated using DCFH-DA, DAPI, and dual staining assays, respectively. The flow cytometry analysis was performed to study the influence of nerolidol on the cell cycle arrest in the HCT-116 cells. The outcomes of the MTT assay demonstrated that nerolidol at different doses (5-100 µM) substantially inhibited the HCT-116 cell viability with an IC50 level of 25 µM. The treatment with nerolidol appreciably boosted the ROS level in the HCT-116 cells. The findings of DAPI and dual staining revealed higher apoptotic incidences in the nerolidol-exposed HCT-116 cells, which supports its ability to stimulate apoptosis. The flow cytometry analysis demonstrated the considerable inhibition in cell cycle at the G0/G1 phase in the nerolidol-exposed HCT-116 cells. Our research showed that nerolidol can inhibit the cell cycle, increase ROS accumulation, and activate apoptosis in HCT-116 cells. In light of this, it may prove to be a potent and salutary candidate to treat colon cancer.

Homeostasis, injury, and recovery dynamics at multiple scales in a self-organizing mouse intestinal crypt

The maintenance of the functional integrity of the intestinal epithelium requires a tight coordination between cell production, migration, and shedding along the crypt-villus axis. Dysregulation of these processes may result in loss of the intestinal barrier and disease. With the aim of generating a more complete and integrated understanding of how the epithelium maintains homeostasis and recovers after injury, we have built a multi-scale agent-based model (ABM) of the mouse intestinal epithelium. We demonstrate that stable, self-organizing behaviour in the crypt emerges from the dynamic interaction of multiple signalling pathways, such as Wnt, Notch, BMP, ZNRF3/RNF43, and YAP-Hippo pathways, which regulate proliferation and differentiation, respond to environmental mechanical cues, form feedback mechanisms, and modulate the dynamics of the cell cycle protein network. The model recapitulates the crypt phenotype reported after persistent stem cell ablation and after the inhibition of the CDK1 cycle protein. Moreover, we simulated 5-fluorouracil (5-FU)-induced toxicity at multiple scales starting from DNA and RNA damage, which disrupts the cell cycle, cell signalling, proliferation, differentiation, and migration and leads to loss of barrier integrity. During recovery, our in silico crypt regenerates its structure in a self-organizing, dynamic fashion driven by dedifferentiation and enhanced by negative feedback loops. Thus, the model enables the simulation of xenobiotic-, in particular chemotherapy-, induced mechanisms of intestinal toxicity and epithelial recovery. Overall, we present a systems model able to simulate the disruption of molecular events and its impact across multiple levels of epithelial organization and demonstrate its application to epithelial research and drug development.

Dermatan Sulfate/Chitosan Nanoparticles Loaded with an Anti-Inflammatory Peptide Increase the Response of Human Colorectal Cancer Cells to 5-Fluorouracil

The gold standard drug for colorectal cancer (CRC) treatment, 5-Fluorouracil (5-FU), induces pharmacological tolerance in long-term management. The transcriptional factor nuclear factor kappa-light-chain-enhancer of activated B cells (NFκB) plays a key role in 5-FU resistance. The aim of this work is to study the capability of polyelectrolytes complex nanoparticles of dermatan sulfate (DS) and chitosan (CS), loaded with the anti-inflammatory tripeptide IRW, to sensitize colorectal cancer cells to 5-FU. Fluorescence and flow cytometry studies confirmed the recognition by the nanoformulation, of the cluster of differentiation 44 (CD44) receptor, involved in the initiation and progression of colorectal tumors. Dynamic light scattering (DLS) and flow cytometry reinforced the importance of DS and CD44 receptor in the interaction, as the addition of DS or anti-CD44 antibody blocked the binding. Moreover, the nanoformulation also interacts with 3D colon cancer cultures, namely colonospheres, enriched in cancer stem cells (CSC), subpopulation responsible for drug resistance and metastasis. To evaluate the consequences of this interaction, the subcellular distribution of the transcriptional factor NFκB, is determined by immunofluorescence analysis. Internalization and the intracellular release of IRW inhibited nuclear translocation of NFκB and increased cellular sensitivity to 5-FU. Altogether, the nanoformulation could provide a selective delivery platform for IRW distribution to colorectal tumors, being an innovative strategy toward overcoming 5-FU resistance in CRC therapy.

Evaluation of dried blood spots as an alternative sampling strategy for 5-fluorouracil monitoring: From method development to clinical application

Therapeutic drug monitoring (TDM) of 5-Fluorouracil (5-FU) is strongly recommended because of its large inter-individual pharmacokinetic variability, narrow therapeutic window, and incidence of toxicity. However, there are several factors that limit the application of TDM in clinical settings. Considering the intrinsic advantages of dried microsamples, such as minimally invasive sampling, analyte stability, and cost-effective logistics, this study aimed to develop a method for the determination of 5-FU in dried blood spots (DBS) using ultra-high liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) and to evaluate its clinical application. Sample preparation was based on an aqueous extraction followed by protein precipitation. Separation was performed in an Acquity UPLC® HSS C18 (150 ×2.1 mm, 1.8 µm), and the mobile phases were water and acetonitrile with 0.5% acetic acid. The total run time was 5.5 min. The method was linear from 100 to 2000 ng/mL, precise (maximum CV% of 7.5%), and accurate (98.3-115.4%). The average recovery was 70%. Blood hematocrit had a minimal impact on the assay. DBS samples were stable for 21 days at 4, 25, and 45 °C. A total of 40 paired samples of plasma, capillary DBS, and venous DBS were analyzed. Median 5-FU concentrations were 444.7, 637.0, and 499.7 ng/mL for plasma, capillary DBS, and venous DBS, respectively. Capillary and plasma concentrations were significantly correlated (r > 0.90), but there was a lack of agreement between the methods, as capillary DBS levels were on average 146% of plasma. Venous DBS corresponded to 110% of the measured plasma concentrations, with a strong correlation (r > 0.97) and agreement between the methods. Our study is the first to report the use of DBS samples to quantify 5-FU. Further studies are needed to establish whether capillary samples can replace plasma.

A dynamic model of the intestinal epithelium integrates multiple sources of preclinical data and enables clinical translation of drug-induced toxicity

We have built a quantitative systems toxicology modeling framework focused on the early prediction of oncotherapeutic-induced clinical intestinal adverse effects. The model describes stem and progenitor cell dynamics in the small intestinal epithelium and integrates heterogeneous epithelial-related processes, such as transcriptional profiles, citrulline kinetics, and probability of diarrhea. We fitted a mouse-specific version of the model to quantify doxorubicin and 5-fluorouracil (5-FU)-induced toxicity, which included pharmacokinetics and 5-FU metabolism and assumed that both drugs led to cell cycle arrest and apoptosis in stem cells and proliferative progenitors. The model successfully recapitulated observations in mice regarding dose-dependent disruption of proliferation which could lead to villus shortening, decrease of circulating citrulline, increased diarrhea risk, and transcriptional induction of the p53 pathway. Using a human-specific epithelial model, we translated the cytotoxic activity of doxorubicin and 5-FU quantified in mice into human intestinal injury and predicted with accuracy clinical diarrhea incidence. However, for gefitinib, a specific-molecularly targeted therapy, the mice failed to reproduce epithelial toxicity at exposures much higher than those associated with clinical diarrhea. This indicates that, regardless of the translational modeling approach, preclinical experimental settings have to be suitable to quantify drug-induced clinical toxicity with precision at the structural scale of the model. Our work demonstrates the usefulness of translational models at early stages of the drug development pipeline to predict clinical toxicity and highlights the importance of understanding cross-settings differences in toxicity when building these approaches.

3D-Printed Tumor-on-Chip for the Culture of Colorectal Cancer Microspheres: Mass Transport Characterization and Anti-Cancer Drug Assays

Tumor-on-chips have become an effective resource in cancer research. However, their widespread use remains limited due to issues related to their practicality in fabrication and use. To address some of these limitations, we introduce a 3D-printed chip, which is large enough to host ~1 cm3 of tissue and fosters well-mixed conditions in the liquid niche, while still enabling the formation of the concentration profiles that occur in real tissues due to diffusive transport. We compared the mass transport performance in its rhomboidal culture chamber when empty, when filled with GelMA/alginate hydrogel microbeads, or when occupied with a monolithic piece of hydrogel with a central channel, allowing communication between the inlet and outlet. We show that our chip filled with hydrogel microspheres in the culture chamber promotes adequate mixing and enhanced distribution of culture media. In proof-of-concept pharmacological assays, we biofabricated hydrogel microspheres containing embedded Caco2 cells, which developed into microtumors. Microtumors cultured in the device developed throughout the 10-day culture showing >75% of viability. Microtumors subjected to 5-fluorouracil treatment displayed <20% cell survival and lower VEGF-A and E-cadherin expression than untreated controls. Overall, our tumor-on-chip device proved suitable for studying cancer biology and performing drug response assays.

Review of 5-FU resistance mechanisms in colorectal cancer: clinical significance of attenuated on-target effects

The emergence of chemoresistant disease during chemotherapy with 5-Fluorouracil-based (5-FU-based) regimens is an important factor in the mortality of metastatic CRC (mCRC). The causes of 5-FU resistance are multi-factorial, and besides DNA mismatch repair deficiency (MMR-D), there are no widely accepted criteria for determining which CRC patients are not likely to be responsive to 5-FU-based therapy. Thus, there is a need to systematically understand the mechanistic basis for 5-FU treatment failure and an urgent need to develop new approaches for circumventing the major causes of 5-FU resistance. In this manuscript, we review mechanisms of 5-FU resistance with an emphasis on: (1) altered anabolic metabolism limiting the formation of the primary active metabolite Fluorodeoxyuridylate (5-Fluoro-2'-deoxyuridine-5'-O-monophosphate; FdUMP); (2) elevated expression or activity of the primary enzymatic target thymidylate synthase (TS); and (3) dysregulated programmed cell death as important causes of 5-FU resistance. Importantly, these causes of 5-FU resistance can potentially be overcome through the use of next-generation fluoropyrimidine (FP) polymers (e.g., CF10) that display reduced dependence on anabolic metabolism and more potent TS inhibitory activity.

An efficient cellular image-based platform for high-content screening of neuroprotective agents against chemotherapy-induced neuropathy

Chemotherapy-induced peripheral neuropathy (CIPN) is a major dose-limiting side effect, with no approved therapy for prevention or treatment. Here, we aimed to establish a high-content image platform based on the neurite outgrowth of dorsal root ganglia (DRG)-derived neuron cells for the discovery of neuroprotective agents against paclitaxel-induced CIPN. ND7/23 cells, an immortalized hybrid DRG cell line, were maturely differentiated by induction with nerve growth factor and upregulation of intracellular cAMP levels. High-content image analyses of the neurofilament-stained neurite network showed that paclitaxel disrupted the neurite outgrowth of well-differentiated ND7/23 DRG neuron cells, recapitulating characteristic effects of paclitaxel on primary cultured DRG neurons. This process coincided with the upregulated activity of store-operated Ca²⁺ entry, similar to those found in rodent models of paclitaxel-induced CIPN. The previously identified neuroprotective agents, minoxidil and 8-Br-cyclic adenosine monophosphate ribose (8-Br-cADPR), attenuated the reduction in total neurite outgrowth in paclitaxel-damaged ND7/23 cells. Additionally, the total neurite outgrowth of well-differentiated ND7/23 cells was concentration-dependently reduced by the neurotoxic chemotherapeutic agents, oxaliplatin and bortezomib, but not the less neurotoxic 5-fluorouracil. We demonstrated that high-content analyses of neurite morphology in well-differentiated DRG neuron-derived cells provide an effective, reproducible, and high-throughput strategy for developing therapeutics against CIPN.

Pyrazole-sulfonamide scaffold featuring dual-tail strategy as apoptosis inducers in colon cancer

Dual-tail strategy has been successfully utilized in the development of novel carbonic anhydrase IX (CA IX) inhibitors. Herein we adopted this approach in the design and synthesis of a series of novel pyridine sulfonamide-pyrazole hybrid scaffold mimicking dual-tail inhibitors of CA IX. A library of 15 compounds was synthesized and assessed for their potential cytotoxic effects against colorectal cancer cells. Compounds 3, and 11 induced potential cytotoxic effects against the three cancer cell lines (HCT-116, HT-29, and SW-620) with IC₅₀s' of 45.88, 28.27, and 16.57 uM, 25.01, 8.99, and 3.27 µM, respectively. Both compounds induced cellular apoptosis on HCT-116 and SW-620 cells, while compound 3 induced necrosis as well. In addition, both compounds induced cell cycle arrest on G0/G1, and S phases. Also, compound 11 showed potential autophagy induction on both colon cancer cell lines (HCT-116, and HT-29), and a little bit on metastatic type. Both compounds were less cytotoxic than the reference drug on normal epithelial cell. The migration rates of HCT-116 and the metastatic one SW-620 were reduced by both compounds. Finally, molecular docking of compounds 3 and 11 into the active site of CA IX confirmed in vitro inhibitory activity for both compounds.

EIF3D promotes resistance to 5-fluorouracil in colorectal cancer through upregulating RUVBL1

BACKGROUND

As EIF3D is oncogenic in colorectal cancer (CRC) and is associated with multidrug resistance, this study aims to investigate whether and how EIF3D regulates resistance to 5-fluorouracil (5-Fu) in CRC.

METHODS

EIF3D-associated genes in CRC were predicted using bioinformatics tools. CRC cells and nude mice received 5-Fu treatment. Then, the impacts of EIF3D and the interaction between EIF3D and RUVBL1 on cell viability, colony formation, apoptosis, and DNA damage were detected through MTT, colony formation, flow cytometry, and immunofluorescence assays, and those on in vivo tumorigenesis through murine xenograft assay. IC50 value of 5-Fu for CRC cells was determined by probit regression analysis. Expressions of EIF3D, eIF4E, EIF3D-associated genes, γH2AX, Bcl-2, Bax, and Cleaved Caspase-3/Caspase-3 in CRC tissues, cells, and/or xenograft tumors were analyzed by qRT-PCR and/or Western blot.

RESULTS

EIF3D and RUVBL1 were highly expressed and positively correlated with CRC tissues/cells. In CRC cells, except for eIF4E, both EIF3D and RUVBL1 levels were upregulated by 5-Fu treatment; in addition to that, RUVBL1 level was downregulated by EIF3D silencing rather than eIF4E. Meanwhile, EIF3D silencing diminished IC50 value of 5-Fu and potentiated 5-Fu-induced viability decrease, colony formation inhibition, apoptosis promotion, Bcl-2 downregulation, and γH2AX, Bax, and Cleaved Caspase-3/Caspase-3 upregulation but reversed 5-Fu-triggered RUVBL1 upregulation. RUVBL1 overexpression offsets EIF3D silencing-induced viability decrease and apoptosis promotion of 5-Fu-treated CRC cells, and tumorigenesis suppression and apoptosis promotion in 5-Fu-treated mice.

CONCLUSION

EIF3D promotes resistance to 5-Fu in CRC through upregulating RUVBL1 level.

Tadalafil increases the antitumor activity of 5-FU through inhibiting PRMT5-mediated glycolysis and cell proliferation in colorectal cancer

BACKGROUND

Protein arginine methyltransferase 5 (PRMT5) is upregulated in multiple tumors and plays a pivotal role in cancer cell proliferation. However, the role of PRMT5 in colorectal cancer remains poorly understood.

METHODS

We detected the expression level of PRMT5 and glycolytic enzymes using online databases and colorectal cancer cell lines by immunohistochemical staining, quantitative real-time polymerase chain reaction (qRT-PCR), and western blotting. And MTT and colony formation assays were conducted to investigate cell proliferation. Then, we evaluated ECAR and OCR levels using a biological energy analyzer to investigate the energy status of colorectal cancer, and the transcriptional regulation was detected by dual luciferase reporter assay and ChIP assay. Finally, the efficacy of combined treatment of tadalafil and 5-FU was verified.

RESULTS

PRMT5 was highly expressed in colorectal cancer tissues compared with their normal counterparts and correlated with poor prognosis in CRC patients. Then, we demonstrated that PRMT5 knockdown or loss of function attenuated the viability of CRC cells, while overexpression of PRMT5 promoted cell proliferation. Mechanistically, PRMT5 enhanced glycolysis through transcriptionally activating LDHA expression. In addition, the PRMT5 inhibitor, tadalafil, rendered CRC cells sensitive to antitumor agent 5-FU in vitro and in vivo.

CONCLUSIONS

Our data indicates that PRMT5 promoted colorectal cancer proliferation partially through activating glycolysis and may be a potential target for colorectal cancer therapy.

Emerging Nanotheranostics for 5-Fluorouracil in Cancer Therapy: A Systematic Review on Efficacy, Safety, and Diagnostic Capability

The conventional concept of using nanocarriers to deliver chemotherapeutic drugs has advanced to accommodate additional diagnostic capability. Nanotheranostic agents (NTA), combining both treatment and diagnostic tools, are an ideal example of engineering-health integration for cancer management. Owing to the diverse materials used to construct NTAs, their safety, effectiveness, and diagnostic accuracy could vary substantially. This systematic review consolidated current NTAs incorporating 5-fluorouracil and elucidated their toxicity, anticancer efficacy, and imaging capability. Medline and Embase databases were searched up to March 18, 2022. The search, selection, and extraction were performed by the preferred reporting items for systematic reviews and meta-analysis (PRISMA) guidelines to ensure completeness and reproducibility. Original research papers involving 5-fluorouracil in the preparation of nanoparticles which reported their efficacy, toxicity, and diagnostic capability in animal cancer models were recruited. The quality of included studies was assessed using the Collaborative Approach to Meta-Analysis and Review of Animal Data from Experimental Studies (CAMARADES) checklist. Nine studies were eligible for the systematic review. There was no significant toxicity reported based on animal weight and organ histology. Complete tumor remission was observed in several animal models using chemo-thermal ablation with NTAs, proving the enhancement of 5-fluorouracil efficacy. In terms of imaging performance, the time to achieve maximum tumor image intensity correlates with the presence of targeting ligand on NTAs. The NTAs, which are composed of tumor-targeting ligands, hold promises for further development. Based on the input of current NTA research on cancer, this review proposed a checklist of parameters to recommend researchers for their future NTA testing, especially in animal cancer studies. Systematic Review Registration: website, identifier registration number.

Casticin Impacts Key Signaling Pathways in Colorectal Cancer Cells Leading to Cell Death with Therapeutic Implications

Colorectal cancer is the third most frequently encountered cancer worldwide. While current chemotherapeutics help to manage the disease to some extent, they have eluded achieving complete remission and are limited by their severe side effects. This warrants exploration of novel agents that are efficacious with anticipation of minimal adverse effects. In the current study, casticin, a tetramethoxyflavone, was tested for its ability to inhibit the viability of three human colorectal cancer cells: adenocarcinoma (DLD-1, Caco-2 cell lines) and human colorectal carcinoma cells (HCT116 cell line). Casticin showed potent inhibition of viability of DLD-1 and HCT116 cells. Clonogenic assay performed in DLD-1 cells revealed that casticin impeded the colony-forming efficiency of the cells, suggesting its impact on the proliferation of these cells. Further, a sustained effect of the inhibitory action upon withdrawal of the treatment was observed. Elucidation of the mechanism of action revealed that casticin impacted the extrinsic programmed cell death pathway, leading to an increase in apoptotic cells. Further, Bcl-2, the key moiety of cell survival, was affected. Notably, a significant number of cells were arrested in the G2/M phase of the cell cycle in DLD-1 cells. Due to the multifaceted action of casticin, we envision that treatment with casticin could provide an efficacious treatment option for colorectal adenocarcinomas with minimal side effects.

Oral cryotherapy for management of chemotherapy-induced oral mucositis in haematopoietic cell transplantation: a systematic review

Background

Oral mucositis (OM) is known to be the most common and challenging side effect of conditioning chemotherapy in haematopoietic cell transplant (HCT). This side effect causes significant morbidity and may delay the treatment plan, as well as increase therapeutic expenses. There are few clinical trials in the literature that indicate any kind of treatment or prevention methods are effective. Therefore, the aim of this study is to perform a systematic review of literature and examine the effectiveness of oral cryotherapy (OC) in management of chemotherapy-induced OM in patients with haematological malignancies undergoing a HCT.

Methods

A systematic literature search was conducted, using the electronic databases PubMed, Embase, MEDLINE and Scopus. A total of 322 papers were identified and 9 papers were analysed based on defined inclusion and exclusion criteria. The quality of the chosen primary studies was appraised using the COCHRANE risk of bias assessment tool.

Results

Nine randomized controlled trials, analysing 658 participants; control group (n = 289, age mean ± SD; 41.15 ± 21) and treatment group (n = 369, age mean ± SD; 39.15 ± 20), were included in this systematic review. Seven studies had significantly addressed the effectiveness of OC (p value < 0.05), in reducing the incidence of developing severe OM in the adult population undergoing HCT, especially when the conditioning regimen protocols included high dose of alkylating agent such as melphalan.

Conclusion

This review supports the use of OC for prevention of OM in patients undergoing HCT, with high-dose of melphalan conditioning protocols. It is recommended that more studies be conducted to compare efficacy and duration of OC with other chemotherapeutic agents with relatively short plasma half-lives. The heterogeneity of the trials demonstrated the need to regulate the validated assessment tools and similar interventions that would enable comparisons and analyses of treatment effects based on well-designed RCTs.

MicroRNAs and drug resistance in colorectal cancer with special focus on 5-fluorouracil

Colorectal cancer is globally one of the most common cancers in all age groups. The current chemotherapy combinations for colorectal cancer treatment include 5-fluorouracil-based regimens; however, drug resistance remains one of the main reasons for chemotherapy failure and disease recurrence. Many studies have determined colorectal cancer chemoresistance mechanisms such as drug efflux, cell cycle arrest, DNA damage repair, apoptosis, autophagy, vital enzymes, epigenetic, epithelial-mesenchymal transition, stem cells, and immune system suppression. Several microRNAs affect drug resistance by regulating the drug resistance-related target genes in colorectal cancer. These drug resistance-related miRNAs may be used as promising biomarkers for predicting drug response or as potential therapeutic targets for treating patients with colorectal cancer. This work reviews and discuss the role of selected microRNAs in 5-fluorouracil resistance and their molecular mechanisms in colorectal cancer.

Melatonin Enhances Anti-tumoral Effects of Menadione on Colon Cancer Cells

BACKGROUND

Colon cancer is one of the most important causes of death in the entire world. New pharmacological strategies are always needed, especially in resistant variants of this pathology. We have previously reported that drugs such as menadione (MEN), D, L-buthionine-S,R-sulfoximine or calcitriol, used in combination, enhanced cell sensibility of breast and colon tumour models, due to their ability to modify the oxidative status of the cells. Melatonin (MEL), a hormone regulating circadian rhythms, has anti-oxidant and anti-apoptotic properties at low concentrations, while at high doses, it has been shown to inhibit cancer cell growth.

OBJECTIVE

The objective of this study is to determine the antitumoral action of the combination MEN and MEL on colon cancer cells.

METHODS

Caco-2 cells were employed to evaluate the effects of both compounds, used alone or combined, on cellular growth/morphology, oxidative and nitrosative stress, and cell migration.

RESULTS

MEN plus MEL dramatically reduced cell proliferation in a time and dose-dependent manner. The antiproliferative effects began at 48 h. At the same time, the combination modified the content of superoxide anion, induced the formation of reactive nitrogen species and enhanced catalase activity. Cell migration process was delayed. Also, changes in nuclear morphology consistent with cell death were observed.

CONCLUSION

The enhanced effect of simultaneous use of MEN and MEL on Caco-2 cells suggests that this combined action may have therapeutic potential as an adjuvant on intestinal cancer acting in different oncogenic pathways.

A narrative review of genetic factors affecting fluoropyrimidine toxicity

OBJECTIVE

Our objective is to document progress in developing personalized therapy with fluoropyrimidine drugs (FPs) to improve outcomes for cancer patients and to identify areas requiring further investigation.

BACKGROUND

FPs including 5-fluorouracil (5-FU), are among the most widely used drugs for treating colorectal cancer (CRC) and other gastrointestinal (GI) malignancies. While FPs confer a survival benefit for CRC patients, serious systemic toxicities, including neutropenia, occur in ~30% of patients with lethality in 0.5-1% of patients. While serious systemic toxicities may occur in any patient, patients with polymorphisms in DPYD, which encodes the rate-limiting enzyme for pyrimidine degradation are at very high risk. Other genetic factors affecting risk for 5-FU toxicity, including miR-27a, are under investigation.

METHODS

Literature used to inform the text of this article was selected from PubMed.gov from the National Library of Medicine while regulatory documents were identified via Google search.

CONCLUSIONS

Clinical studies to date have validated four DPYD polymorphisms (DPYD*2A, DPYD*13, c.2846A>T, HapB3) associated with serious toxicities in patients treated with 5-FU. Genetic screening for these is being implemented in the Netherlands and the UK and has been shown to be a cost-effective way to improve outcomes. Factors other than DPYD polymorphisms (e.g., miR-27a, TYMS, ENOSF1, p53) also affect 5-FU toxicity. Functional testing for deficient pyrimidine catabolism {defined as [U] >16 ng/mL or [UH2]:[U] <10} is being implemented in France and has demonstrated utility in identifying patients with elevated risk for 5-FU toxicity. Therapeutic drug monitoring (TDM) from plasma levels of 5-FU during first cycle treatment also is being used to improve outcomes and pharmacokinetic-based dosing is being used to increase the percent of patients within optimal area under the curve (AUC) (18-28 mg*h/L) values. Patients maintained in the optimal AUC range experienced significantly reduced systemic toxicities. As understanding the genetic basis for increased risk of 5-FU toxicity becomes more refined, the development of functional-based methods to optimize treatment is likely to become more widespread.

New insights into the mechanisms underlying 5-fluorouracil-induced intestinal toxicity based on transcriptomic and metabolomic responses in human intestinal organoids

5-Fluorouracil (5-FU) is a widely used chemotherapeutical that induces acute toxicity in the small and large intestine of patients. Symptoms can be severe and lead to the interruption of cancer treatments. However, there is limited understanding of the molecular mechanisms underlying 5-FU-induced intestinal toxicity. In this study, well-established 3D organoid models of human colon and small intestine (SI) were used to characterize 5-FU transcriptomic and metabolomic responses. Clinically relevant 5-FU concentrations for in vitro testing in organoids were established using physiologically based pharmacokinetic simulation of dosing regimens recommended for cancer patients, resulting in exposures to 10, 100 and 1000 µM. After treatment, different measurements were performed: cell viability and apoptosis; image analysis of cell morphological changes; RNA sequencing; and metabolome analysis of supernatant from organoids cultures. Based on analysis of the differentially expressed genes, the most prominent molecular pathways affected by 5-FU included cell cycle, p53 signalling, mitochondrial ATP synthesis and apoptosis. Short time-series expression miner demonstrated tissue-specific mechanisms affected by 5-FU, namely biosynthesis and transport of small molecules, and mRNA translation for colon; cell signalling mediated by Rho GTPases and fork-head box transcription factors for SI. Metabolomic analysis showed that in addition to the effects on TCA cycle and oxidative stress in both organoids, tissue-specific metabolic alterations were also induced by 5-FU. Multi-omics integration identified transcription factor E2F1, a regulator of cell cycle and apoptosis, as the best key node across all samples. These results provide new insights into 5-FU toxicity mechanisms and underline the relevance of human organoid models in the safety assessment in drug development.

Evolving Role of Pharmacogenetic Biomarkers to Predict Drug-Induced Hematological Disorders

ABSTRACT

Drug-induced hematological disorders constitute up to 30% of all blood dyscrasias seen in the clinic. Hematologic toxicity from drugs may range from life-threatening marrow aplasia, agranulocytosis, hemolysis, thrombosis to mild leukopenia, and thrombocytopenia. Pathophysiologic mechanisms underlying these disorders vary from an extension of the pharmacological effect of the drug to idiosyncratic and immune-mediated reactions. Predicting these reactions is often difficult, and this makes clinical decision-making challenging. Evidence supporting the role of pharmacogenomics in the management of these disorders in clinical practice is rapidly evolving. Despite the Clinical Pharmacology Implementation Consortium and Pharmacogenomics Knowledge Base recommendations, few tests have been incorporated into routine practice. This review aims to provide a comprehensive summary of the various drugs which are implicated for the hematological adverse events, their underlying mechanisms, and the current evidence and practical recommendations to incorporate pharmacogenomic testing in clinical care for predicting these disorders.

Population pharmacokinetic and pharmacodynamic modeling of capecitabine and its metabolites in breast cancer patients

PURPOSE

The present study was performed to examine relationships between systemic exposure of capecitabine metabolites (5-FU, 5'-DFCR and 5'-DFUR) and toxicity or clinical response in patients with metastatic breast cancer.

METHODS

A population pharmacokinetic model for capecitabine and its three metabolites was built. Typical parameter values, characteristics of random distributions, associated with parameters, and covariates impact were estimated. Area under the curve (AUC) were computed for 5-FU and compared with grades of toxicity. Pharmacokinetic modeling was based on data collected on the first treatment cycle. Toxicity was assessed on the two first treatment cycles.

RESULTS

The study was conducted in 43 patients. The population pharmacokinetic model (a one-compartment model per compound) was able to capture the very complex absorption process of capecitabine. Statistically significant covariates were cytidine deaminase, alkaline phosphatase and dihydrouracilemia (UH2)/uracilemia (U) ratio. UH2/U ratio was the most significant covariate on 5-FU elimination and CDA on the transformation of 5'-DFCR in 5'-DFUR. A trend was observed between 5-FU AUC and thrombopenia toxicity grades, but not with other toxicities. Best clinical response was not linked to systemic exposure of capecitabine metabolites.

CONCLUSION

In our study, we propose a model able to describe, meanwhile, and its main metabolites, with a complex absorption process and inclusion of enzyme activity covariates such as CDA and UH2/U ratio. Trial registration Eudract 2008-004136-20, 2008/11/26.

Overcoming barriers to implementing precision dosing with 5-fluorouracil and capecitabine

Despite advances in targeted cancer therapy, the fluoropyrimidines 5-fluorouracil (5FU) and capecitabine continue to play an important role in oncology. Historically, dosing of these drugs has been based on body surface area. This approach has been demonstrated to be an imprecise way to determine the optimal dose for a patient. Evidence in the literature has demonstrated that precision dosing approaches, such as DPD enzyme activity testing and, in the case of intravenous 5FU, pharmacokinetic-guided dosing, can reduce toxicity and yield better patient outcomes. However, despite the evidence, there has not been uniform adoption of these approaches in the clinical setting. When a drug such as 5FU has been used clinically for many decades, it may be difficult to change clinical practice. With the aim of facilitating change of practice, issues and barriers to implementing precision dosing approaches for 5FU and capecitabine are identified and discussed with possible solutions proposed.

Fluorescent molecular rotors as sensors for the detection of thymidine phosphorylase

Three new fluorescent molecular rotors were synthesized with the aim of using them as sensors to dose thymidine phosphorylase, one of the target enzymes of 5-fluorouracil, a potent chemotherapic drug largely used in the treatment of many solid tumors, that acts by hindering the metabolism of pyrimidines. 5-Fluorouracil has a very narrowtherapeutic window, in fact, its optimal dosage is strictly related to the level of its target enzymes that vary significantly among patients, and it would be of the utmost importance to have an easy and fast method to detect and quantify them. The three molecular rotors developed as TP sensors differ in the length of the alkylic spacer joining the ligand unit, a thymine moiety, and the fluorescent molecular rotor, a [4-(1-dimethylamino)phenyl]-pyridinium bromide. Their ability to trigger an optical signal upon the interaction with thymidine phosphorylase was investigated by fluorescent measurements.

Case report: severe toxicity in an African-American patient receiving FOLFOX carrying uncommon allelic variants in DPYD

Cancers of the colon are commonly treated with fluoropyrimidines, which often cause severe toxicities in patients with certain variants in DPYD. Y186C (rs115232898) and a variant in the 3' untranslated region (rs12132152) are uncommon alleles previously observed in African-Americans. An African-American female underwent 5-fluorouracil-based therapy (400 mg/m2 bolus, 1200 mg/m2/day over 46 h). The patient experienced severe pancytopenia after the first cycle. After 5-fluorouracil (5-FU) dose reduction (600 mg/m2/day), the steady-state 5-FU plasma concentration became 474 ng/ml (range 301-619 ng/ml) and increased following a subsequence dose increase (800 mg/m2/day; 1248 ng/ml). After a 1000 mg/m2/day dose resulted in myelosuppression, 5-FU was again de-escalated for the remaining cycles (600 mg/m2). The observed complications are likely a function of uncommon genetic variants that affect DPYD metabolism.

Association of 5-FU Therapeutic Drug Monitoring to DPD Phenotype Assessment May Reduce 5-FU Under-Exposure

In order to limit 5-fluorouracil (5-FU) toxicity, some health agencies recommend evaluating dihydropyrimidine dehydrogenase (DPD) deficiency before any 5-FU treatment introduction. In our study, we investigated relationships between 5-FU clearance and markers of DPD activity such as uracilemia (U), dihydrouracilemia (UH₂)/U ratio, or genotype of the gene encoding DPD (DPYD). All patients with gastrointestinal cancers who received 5-FU-based regimens form March 2018 to June 2020 were included in our study. They routinely benefited of a pre-therapeutic DPYD genotyping and phenotyping. During 5-FU infusion, blood samples were collected to measure 5-FU steady-state concentration in order to adapt 5-FU doses at the following cycles. A total of 169 patients were included. Median age was 68 (40–88) years and main primary tumor sites were colorectal (40.8%) and pancreas (31.4%), metastatic in 76.3%. 5-FU was given as part of FOLFIRINOX (44.4%), simplified FOLFOX-6 (26.6%), or docetaxel/FOLFOX-4 (10.6%). Regarding DPD activity, median U and UH₂/U were, respectively, 10.8 ng/mL and 10.1, and almost 15% harbored a heterozygous mutation. On the range of measured U and UH₂/U, no correlation was observed with 5-FU clearance. Moreover, in patients with U < 16 ng/mL, 5-FU exposure was higher than in other patients, and most of them benefited of dose increase following 5-FU therapeutic drug monitoring (TDM). If recent guidelines recommend decreasing 5-FU dose in patients harboring U ≥ 16 ng/mL, our study highlights that those patients are at risk of under-exposure and that 5-FU TDM should be conducted in order to avoid loss of efficacy.

DPYD and UGT1A1 Pharmacogenetic Testing in Patients with Gastrointestinal Malignancies: An Overview of the Evidence and Considerations for Clinical Implementation

Gastrointestinal (GI) malignancies are among the most commonly diagnosed cancers worldwide. Despite the introduction of targeted and immunotherapy agents in the treatment landscape, cytotoxic agents, such as fluoropyrimidines and irinotecan, remain as the cornerstone of chemotherapy for many of these tumors. Pharmacogenetics (PGx) is a rapidly evolving field that accounts for interpatient variability in drug metabolism to predict therapeutic response and toxicity. Given the significant incidence of severe treatment-related adverse events associated with cytotoxic agents, utilizing PGx can allow clinicians to better anticipate drug tolerability while minimizing treatment interruptions or delays. In this review, the PGx profiles of drug-gene pairs with potential impact in GI malignancy therapy - DPYD-5-fluorouracil/capecitabine and UGT1A1-irinotecan - and the available clinical evidence of their roles in reducing severe adverse events are discussed. Considerations for clinical implementation, such as optimal laboratory workflows, electronic health record integration, and stakeholder engagement, as well as provider education, are addressed. Last, exploratory PGx markers in GI malignancy treatment are described. As the PGx knowledge base rapidly evolves, pharmacists will be vital in leveraging their pharmacology knowledge and clinical skills to implement PGx testing in the clinic.

5-Fluorouracil resistance mechanisms in colorectal cancer: From classical pathways to promising processes

Colorectal cancer (CRC) is a public health problem. It is the third most common cancer in the world, with nearly 1.8 million new cases diagnosed in 2018. The only curative treatment is surgery, especially for early tumor stages. When there is locoregional or distant invasion, chemotherapy can be introduced, in particular 5-fluorouracil (5-FU). However, the disease can become tolerant to these pharmaceutical treatments: resistance emerges, leading to early tumor recurrence. Different mechanisms can explain this 5-FU resistance. Some are disease-specific, whereas others, such as drug efflux, are evolutionarily conserved. These mechanisms are numerous and complex and can occur simultaneously in cells exposed to 5-FU. In this review, we construct a global outline of different mechanisms from disruption of 5-FU-metabolic enzymes and classic cellular processes (apoptosis, autophagy, glucose metabolism, oxidative stress, respiration, and cell cycle perturbation) to drug transporters and epithelial-mesenchymal transition induction. Particular interest is directed to tumor microenvironment function as well as epigenetic alterations and miRNA dysregulation, which are the more promising processes that will be the subject of much research in the future.

5-Fluorouracil Response Prediction and Blood Level-Guided Therapy in Oncology: Existing Evidence Fundamentally Supports Instigation

5-Fluorouracil (5-FU) response prediction and therapeutic drug monitoring (TDM) are required to minimize toxicity while preserving efficacy. Conventional 5-FU dose normalization uses body surface area. It is characterized by up to 100-fold interindividual variability of pharmacokinetic (PK) parameters, and typically >50% of patients have plasma 5-FU concentrations outside the optimal range. This underscores the need for a different dose rationalization paradigm, hence there is a case for 5-FU TDM. An association between 5-FU PK parameters and efficacy/toxicity has been established. It is believed that 5-FU response is enhanced and toxicity is reduced by PK management of its dosing. The area under the concentration-time curve is the most relevant PK parameter associated with 5-FU efficacy/toxicity, and optimal therapeutic windows have been proposed. Currently, there is no universally applied a priori test for predicting 5-FU response and identifying individuals with an elevated risk of toxicity. The following two-step strategy: prediction of response/toxicity and TDM for subsequent doses seems plausible. Approximately 80% of 5-FU is degraded in a three-step sequential metabolic pathway. Dihydropyrimidine dehydrogenase (DPD) is the initial and rate-limiting enzyme. Its deficiency can cause toxicity with standard 5-FU doses. DPD also metabolizes uracil (U) into 5,6-dihydrouracil (UH2). The UH2/U ratio is an index of DPD activity and a credible biomarker of response and toxicity. This article outlines the UH2/U ratio as a parameter for 5-FU response/toxicity prediction and highlights key studies emphasizing the value of 5-FU TDM. Broad application of 5-FU response/toxicity prediction and blood level-guided therapy remains unmet, despite ever-increasing clinical interest. Considered collectively, existing evidence is compelling and fundamentally supports universal instigation of response/toxicity prediction and TDM.

Pharmacogenomics of anticancer drugs: Personalising the choice and dose to manage drug response

The field of pharmacogenomics has made great strides in oncology over the last 20 years and indeed a significant number of pre-emptive genetic tests are now routinely undertaken prior to anticancer drug administration. Many of these gene-drug interactions are the fruits of candidate gene and genome-wide association studies, which have largely focused on common genetic variants (allele frequency>1%). Examples where there is clinical utility include genotyping or phenotyping for G6PD to prevent rasburicase-induced RBC haemolysis, and TPMT to prevent thiopurine-induced bone marrow suppression. Other associations such as CYP2D6 status in determining the efficacy of tamoxifen are more controversial because of contradictory evidence from different sources, which has led to variability in the implementation of testing. As genomic technology becomes ever cheaper and more accessible, we must look to the additional data our genome can provide to explain interindividual variability in anticancer drug response. Clearly genes do not act on their own and it is therefore important to investigate genetic factors in conjunction with clinical factors, interacting concomitant drug therapies and other factors such as the microbiome, which can all affect drug disposition. Taking account of all of these factors, in conjunction with the somatic genome, is more likely to provide better predictive accuracy in determining anticancer drug response, both efficacy and safety. This review summarises the existing knowledge related to the pharmacogenomics of anticancer drugs and discusses areas of opportunity for further advances in personalisation of therapy in order to improve both drug safety and efficacy.

Therapeutic Drug Monitoring by Pharmacists: Does It Reduce Costs

Therapeutic drug monitoring (TDM) has as its main objective to ensure that the plasma drug concentration remains within the appropriate range. Regarding the economic dimension of TDM, it is known that there are gains in health outcomes; however, there is still little evidence for the benefit of this procedure performed by pharmacists within the hospital context. With this project, we aimed to create a matrix of cost avoidance associated with TDM performed by pharmacists and to quantify the total avoided costs in 1 year, by implementing a TDM process in a tertiary hospital. For the studied period, we collected 362 pharmaceutical interventions related to TDM of antibiotics performed in adults. As a result, considering these data, the total cost avoidance in 1 year was 371,018 ($416,584.58) at one medical center. We conclude that TDM is highly cost-avoidant and that the implementation costs by pharmaceutical services is clearly lower than the benefit achieved.

Pharmacokinetics-based Dose Management of 5-Fluorouracil Clinical Research in Advanced Colorectal Cancer Treatment

Objective:

The study aimed to explore the efficacy of pharmacokinetic-based 5-fluorouracil dose management by plasma concentration test in advanced colorectal cancer treatment.

Methods:

153 samples of advanced colorectal cancer patients were enrolled and randomly assigned to a control group and an experimental group. All patients received double-week chemotherapy with 5- fluorouracil (four weeks were used as one period), and chemotherapy duration ranged from 2 to 6 periods. In the first period, all patients were administered with the classic strategy of body surface area (BSA).

Results:

In the subsequent periods, the control group (77 samples) continued with BSA guided chemotherapy, while the experimental group (76 samples) received pharmacokinetic AUC-based chemotherapy. The efficacy and toxic side effects were assessed during chemotherapy, and survival was recorded in a follow-up. In the AUC experimental group, the rate of diarrhea significantly decreased (37.50% vs. 70.00%, P=0.010), and incidence of oral mucositis reduced (54.17% vs. 82.50%, P=0.014). Compared with the control group, the clinical benefit rate of experimental group was much higher (90.79% vs. 79.22%, P=0.046).

Conclusion:

There was no significant difference in other 5-fluorouracil related toxic side effect events (nausea, vomiting, hand-foot syndrome) and progression-free survival between the two groups. Pharmacokinetic- based dose management of 5-Fluorouracil reduces the toxicity of chemotherapy and improves long-term efficacy of chemotherapy for advanced colorectal cancer patients.

Single-chain Antibody Against Reg4 Suppresses Gastric Cancer Cell Growth and Enhances 5-FU-induced Cell Death in vitro

BACKGROUND

Regenerating islet-derived gene family member 4 (Reg4), a well-investigated growth factor in the regenerative pancreas, has recently been reported to be highly associated with a majority of gastrointestinal cancers. Pathological hyper-expression or artificial over-expression of Reg4 causes acceleration of tumor growth, migration, and resistance to chemotherapeutic 5-Fluorouracil (5-FU). Until now, no method has been successfully established for eliminating the effects of Reg4 protein.

METHODS

This study reports the production of an engineered immunoglobin, a single-chain variable fragment (scFv-Reg4), to specifically bind Reg4 and block the bioactivity. The complementary-determining regions (CDRs) against Reg4 were assigned using MOE and ZDOCK servers. The binding affinity (KD) was determined by bio-layer interferometry (BLI). MKN45 and AGS cell proliferation was determined by Thiazolyl blue tetrazolium bromide (MTT) method and the cell apoptosis was detected by flow cytometry assay.

RESULTS

The KD of scFv-Reg4 to Reg4 was determined to be 1.91×10-8. In MKN45 and AGS cell lines, scFv- Reg4 depressed Reg4-stimulated cell proliferation and the inhibitory rates were 27.7±1.5% and 17.3±2.6%, respectively. Furthermore, scFv significantly enhanced 5-FU-induced cell death, from 23.0±1.0% to 28.4±1.2% in MKN45 and 28.2±0.7% to 36.6±0.6% in AGS cells. Treatment with scFv alone could lyse cancer cells to a certain extent, but no significance has been observed.

CONCLUSION

The single-chain antibody (scFv-Reg4) significantly inhibited gastric cancer cell proliferation and synergistically enhanced the lethal effect of 5-FU. Thus, traditional chemo-/radio- therapeutics supplemented with scFv-Reg4 may provide advances in the strategy for gastrointestinal cancer treatment.

Fuplatin: An Efficient and Low-Toxic Dual-Prodrug

As FDA-approved chemotherapeutic agents, cisplatin, oxaliplatin, and 5-fluorouracil are widely used in clinic but limited by severe side-effects. To ameliorate their respective defects, a series of "dual-prodrug" by linking oxoplatin and 5-FU were designed and synthesized. The assembled compounds 10-17, named Fuplatin, exhibited much higher cytotoxicity against the tested cancer cells while lower cytotoxicity toward the human normal lung cells than free drugs or their combinations. Among them, 14 enhanced cellular accumulation with 62- and 825-fold amount of oxaliplatin and 8 at 9 h, respectively, significantly induced DNA damage and cell apoptosis, and inhibited migration and invasion in HCT-116 cells. Compound 14 arrested the cell cycle at S and G2 phases and up-regulated thymidylate synthase and p53, consistent with the results of the combination, suggesting 14 adopted a collaborative mode of 5-FU and oxaliplatin to kill cancer cells. In vivo, compound 14 showed high antitumor effect and no observable toxicity in NOD/SCID mice bearing HCT-116 tumors.

Therapeutic drug monitoring as a tool to optimize 5-FU-based chemotherapy in gastrointestinal cancer patients older than 75 years

AIMS

Most clinical trials exclude elderly people, leading to a limited understanding of the benefit-to-risk ratio in this population. Despite existing data regarding the oncological management of elderly receiving fluorouracil (5-FU)-based regimen, our objective was to investigate 5-FU exposure/toxicity relationship in patients ≥75 years and compare the effectiveness of 5-FU therapeutic drug monitoring between elderly and younger patients.

METHODS

Hundred fifty-four patients (31 of whom are older than 75 years) with gastrointestinal cancers, who were to receive 5-FU-based regimens, were included in our study. At cycle 1 (C1), the 5-FU dose was calculated using patient's body surface area, then a blood sample was drawn to measure 5-FU concentration and 5-FU dose was adjusted at the subsequent cycles based on C1 concentration. Assessments of toxicity were performed at the beginning of every cycle.

RESULTS

Seventy-one percent of elderly patients required dose adjustments after C1, compared with 50% for younger patients. Percentages of patients within 5-FU area under the curve range at cycle 2 were 64% and 68%, respectively, for elderly and younger patients. The proportion of elderly patients experiencing severe toxicities fell from 15% at C1 to only 5% at cycle 3.

CONCLUSION

Pharmacokinetic-guided 5-FU-dosing algorithm, leading to an improved tolerability while remaining within therapeutic concentration range, is even more valuable for patients older than 75 years than in younger patients.

How can we best monitor 5-FU administration to maximize benefit to risk ratio?

INTRODUCTION

5-Fluorouracil (5-FU) is currently used as a chemotherapy in several cancers such as head-and-neck (H&N) and colorectal cancers. 5-FU dosing is traditionally based on body surface area (BSA), but this strategy is usually associated with severe toxicities. 5-FU is mainly catabolized by dihydropyrimidine dehydrogenase (DPD), and 5-FU dosage adaptation according to DPD status at the first cycle of treatment is now recommended. To further optimize 5-FU-based chemotherapy, a body of evidences justifies therapeutic drug monitoring (TDM). Areas covered: 5-FU pharmacokinetics, relationships between pharmacokinetics and efficacy or toxicity of 5-FU, proofs of interest of 5-FU TDM and its practical considerations are discussed. Expert opinion: BSA-adjusted 5-FU administration is associated with a large inter-individual variability, and according to this strategy, many patients experience under- or overexposure. Moreover, relationships between 5-FU area under the curve (AUC) and its toxicity or efficacy have been demonstrated, at least in patients with colorectal or H&N cancers. 5-FU therapeutic index has been validated and algorithms of 5-FU dosage adaptation according to its AUC are now available. Advances in pre-analytical and analytical steps of 5-FU TDM make its use feasible in clinical practice. Thus, there are consistent evidences to recommend 5-FU TDM in patients with advanced colorectal or H&N cancers.

[5-fluorouracil therapeutic drug monitoring: Update and recommendations of the STP-PT group of the SFPT and the GPCO-Unicancer]

Despite being 60-years old now, 5-FU remains the backbone of numerous regimen to treat a variety of solid tumors such as breast, head-and-neck and digestive cancers either in neo-adjuvant, adjuvant or metastatic settings. Standard 5-FU usually claims 15-40% of severe toxicities and up to 1% of toxic-death. Numerous studies show a stiff relationship between 5-FU exposure and toxicity or efficacy. In addition, 5-FU pharmacokinetics is highly variable between patients. Indeed, 80% of the 5-FU dose is catabolized in the liver by dihydropyrimidine dehydrogenase (DPD) into inactive compounds. It is now well established that DPD deficiency could lead to severe toxicities and, thus, require dose reduction in deficient patients. However, despite dosage adaptation based on DPD status, some patients may still experience under- or over-exposure, leading to inefficacy or major toxicity. The "Suivi thérapeutique pharmacologique et personnalisation des traitements" (STP-PT) group of the "Société française de pharmacologie et de thérapeutique" (SFPT) and the "Groupe de pharmacologie clinique oncologique" (GPCO)-Unicancer, based on the latest and most up-to-date literature data, recommend the implementation of 5-FU Therapeutic Drug Monitoring in order to ensure an adequate 5-FU exposure.